Radially expandable cannula devices and systems and methods for using the same

Abstract

Cannula devices, systems, and methods for introducing one or more instruments into a patient's body to perform a procedure are provided.SOLUTION: In one example, a cannula device includes first and second housings defining a through hole and a plurality of elongate members extending distally from the housings and cooperatively defining a passageway axially aligned with the through hole between proximal ends and distal tips of the elongate members. The first housing may be axially movable relative to the second housing such that the proximal end of the elongate member moves outwardly to increase the size of the passage, and optionally may be tapered when expanded. Optionally, one or more secondary devices may be provided that may be inserted into the passageway through the through-hole prior to expansion of the passageway, e.g., an obturator having a sharp tip, or an obturator and a tubular access device.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] Related application data This application claims the benefit of U.S. Provisional Application No. 62 / 989,520, filed March 13, 2020, and is a continuation-in-part of U.S. Application No. 16 / 801,088, filed February 25, 2020, which is a continuation-in-part of co-pending International Application No. PCT / CA2018 / 051072, filed September 5, 2018, which claims the benefit of U.S. Provisional Application No. 62 / 554,802, filed September 6, 2017, and Canadian Patent Application No. 2,993,590, filed January 31, 2018, the disclosures of which are expressly incorporated herein by reference.

[0002] The technical field relates generally to methods and devices used in minimally invasive or keyhole surgery. For example, the technical field relates to cannula and trocar devices for insertion into incisions. [Background technology]

[0003] In most minimally invasive abdominal surgeries (laparoscopic surgery), a skin incision is made on the surface of the abdominal wall and several fixed diameter ports (trocars) are inserted into the abdomen to facilitate instrumentation during surgery. Typically, these ports are in the five to twelve millimeter (5-12 mm) diameter range. The fixed diameter ports on the market are concentrated into very similar product offerings with little to no variation, and come with their own set of problems.

[0004] Generally, the force of trocar insertion into tissue is directly proportional to the trocar's diameter. The greater the entry force, the less control the surgeon has during entry, and the more dangerous and risky it becomes for the patient, as the port may accidentally pierce the patient and puncture an internal organ or major blood vessel. This forceful trocar entry remains the leading cause of complications during laparoscopic surgery, contributing to approximately half of all complications that occur during laparoscopic surgery.

[0005] In some cases, it may be necessary to enlarge the diameter of a small port to accommodate larger instruments. These situations may be planned in advance or may be based on emergency situations, such as sudden bleeding requiring the use of a laparoscopic stapler, clip applier, or suture, or a difficult-to-navigate anatomy requiring repositioning of the endoscope or camera. In these situations, the small port is removed and a larger diameter port is inserted through the same trajectory to accommodate the enlargement.

[0006] Oversizing a fixed-diameter port can prove to be an inefficient task for surgeons because larger ports may not be readily available in the operating room, where nurses may need to leave the room to obtain larger devices. Oversizing can also be dangerous to the patient because loss of abdominal pneumoperitoneum occurs when the smaller trocar is removed, resulting in loss of surgical visibility. Pneumoperitoneum must be re-established after inserting a larger trocar to re-establish surgical visibility. Oversizing also poses an additional risk of injury to the patient because abdominal tissues re-approximate after the smaller trocar is removed, causing loss of the original trocar pathway. This is particularly difficult in obese patients, where larger-diameter ports may be inserted all together through different pathways, resulting in additional trauma to the patient and requiring additional punctures that may result in injury.

[0007] In other cases, constant diameter ports can become dislodged and pulled out of the abdominal wall with time and use, which can also result in loss of pneumoperitoneum and add further risk of injury from re-entry.

[0008] For larger fixed diameter ports, especially those larger than ten millimeters (10 mm), the tissue scarring can be significant, necessitating manual suturing of the fascia or the use of a fascial closure (suture) device to reduce the risk of developing a postoperative incisional hernia. This consumes a significant amount of time at the end of the surgery during which the patient must remain under general anesthesia. For patients requiring a fascial closure device, this adds additional time and cost to the surgery.

[0009] The differentiating features among constant diameter ports are subtle and often aim to solve one problem while preventing another. For example, many constant diameter ports have ridges around the cannula that improve fixation within the abdominal wall, but this causes greater insertion forces and potentially larger wound sizes due to the ridges. Other constant diameter ports have bladed tips that reduce insertion forces by cutting through tissue, but they can be more dangerous if they accidentally puncture a viscera or major blood vessel with the blade. Other ports have blunt tips that increase insertion forces, but can dilate tissue fibers instead of cutting them as bladed trocars do, which can result in smaller wounds in the tissue later.

[0010] One way to alleviate some of these problems is to use expansion ports. The first radial expansion port, and currently the only one on the market, is Innerdyne's (now Medtronic) VersaStepPort (U.S. Pat. No. 5,431,676(A), U.S. Pat. No. 20060212062(A1), U.S. Pat. No. 7,896,897(B2)). It includes a mesh sleeve with an outer polymer coating that is inserted into the abdomen with a Veress needle. The Veress needle is then removed, leaving a passageway for a larger member (dilator) to be inserted and expand the mesh sleeve within the abdomen.

[0011] Although the Versa Step Port reduces initial insertion force, it has proven ineffective in other areas. First, the dilator still requires significant brute force to be inserted because it must be inserted through a small passageway and penetrate the solid polymer coating to expand the mesh sleeve. The FDA MAUDE database reports frequent occurrences of polymer coating fragments detaching from the mesh sleeve and being unable to be repaired. Additionally, both the polymer coating and mesh sleeve are made of lubricious materials and often slip off during surgery. This necessitates re-entry, again increasing the risk of injury. If the sleeve slips off the body, its lubricious coating dislodges, preventing easy re-insertion. This necessitates the wasteful use of new mesh sleeve units. Due to the flexible nature of the mesh sleeve and the lack of a solid component to guide the dilator entry in a concentric manner, surgeons may accidentally penetrate the side of the mesh sleeve and perforate abdominal tissue during dilator entry. Upsizing this system is also difficult because a small trocar must be removed from the mesh sleeve while the surgeon attempts to hold the sleeve in place to maintain the same trajectory. The sleeve does not provide protection against gas loss during either upsizing process. Upsizing is wasteful with this system because it requires opening a new, larger-diameter unit containing a new mesh sleeve. If the mesh sleeve fails to hold in the abdomen and slips off, a new sleeve must be utilized as well. Despite these limitations, this system remains an accepted approach for minimally invasive trocar entry, particularly in pediatric procedures. However, issues that arise prevent it from being a widely adopted option, and therefore, there remains a need for a minimally invasive expandable port that performs well and addresses these gaps.

[0012] Problems also exist within the neurosurgical environment, where, for example, a dichotomy exists between the risks and benefits of brain tumor resection. While resection has been shown to increase survival rates, surgeons are limited in their ability to intervene due to the risk of neurological injury. Traditionally, open resections have been performed using flat retractors that apply high pressure over a small surface area, potentially damaging brain tissue, specifically white matter tracts (due to reduced perfusion and localized ischemia), leading to poor outcomes. A limited number of tubular retractor access devices have been developed to address these issues, in which a fixed-diameter (approximately 13 mm) tubular retractor is placed within the brain tissue. The circular / tubular profile of this device helps distribute pressure evenly and radially to the surrounding tissue, thereby reducing the high pressure points and potential damage caused by traditional flat retractors. However, these retractors have not been widely adopted for deep-seated tumors due to the inherent safety risks associated with a large, fixed-diameter entry that can further damage white matter tracts and therefore critical neurological function. As in laparoscopic surgery, there is a need in neurosurgery for a port that provides minimally invasive and single-step radial expansion that reduces trauma to brain tissue.

[0013] Thus, devices, systems, and methods that facilitate access to a subject's body, for example, for the introduction of one or more instruments, would be useful. Summary of the Invention

[0014] The present application is directed to devices, systems, and methods for accessing a subject's body, for example to access a laparoscopic or other surgical space, and more particularly to cannula and trocar devices for insertion into an incision to allow for the introduction of one or more instruments into a subject's body.

[0015] To address one or more of the issues discussed above, particularly those related to the application of high force / brute force, in one example, a method is provided for expanding a port by creating an internal conical taper (or guide) in an elongated rigid member that facilitates easy and controllable entry of a large diameter member into a smaller cannula with less force, the mechanism for creating this conical taper utilizing a novel mechanism that uses the application of force perpendicular to an internal housing to create such a taper, all of which can be done intuitively and efficiently in a surgical environment.

[0016] The vertical expansion mechanism can be used in reverse to cause contraction and does not require the use of a biasing element such as a spring to return the elongated rigid member to its initial position, thereby reducing the amount of force required to cause expansion in tissue.

[0017] Applying a vertical force to create the internal conical taper of the elongated, rigid member also allows a larger member to be inserted in a continuous, single step. The internal conical taper can be created in two ways: 1) by manually or electromechanically applying a vertical force downward (distal) to the first housing within the second housing, causing the proximal region of the elongated, rigid member to increase in cross-sectional area and create the internal conical taper or guide; or 2) by inserting a large, derating member into the first housing containing the resistance member, causing the large member to apply a force downward (distal) to the resistance member, acting on an expansion mechanism within the housing, causing the elongated, rigid member to create the internal conical taper (guide) at the proximal region of the cannula and the proximal region of the tissue. Thus, the interaction of the large member and the resistance member creates the internal conical taper while simultaneously facilitating the single-step movement of inserting the large member and expanding the port. Such a mechanism can also be actuated using electromechanical or robotic systems.

[0018] By creating an internal conical taper using a perpendicular application of force prior to inserting the larger member, insertion becomes less forceful, controllable, and safer. It does not pull or shear internal tissue as a twisting / torquing mechanism would, but instead expands radially so that tissue is less affected.

[0019] The rate of expansion / contraction can be controlled so that the inner conical taper creates a gradual conical passage, preventing any sudden movement and preventing tissue from being subjected to high pressure / force in a short period of time. The user can insert the large member at a speed that is comfortable for them. Given a constant / known amount of force applied by the user or the electromechanical system for a given time interval, the design can also be modified to control the size of the expansion, the degree and size of the inner conical taper created, and how quickly it is created. This can be modified by varying the angle of the angled elongated rigid member, along with the overall length and diameter of the first housing and the diameter of the second housing. Furthermore, in other embodiments, the material selection for the resistance member (e.g., a flat backup valve) and the sheath or cover (sealing elastic member) surrounding the elongated rigid member can be fine-tuned to control the rate of expansion / contraction when applying a known amount of force to expand / contract.

[0020] The larger members can also vary in diameter and do not need to have a predetermined size before expansion. For example, the smaller members may be inserted first, and when the user realizes they need the larger members, they can remove them and seamlessly insert and position the larger members into the tissue without loss of trocar functionality or loss of pneumoperitoneum.

[0021] In addition to the primary expansion mechanism, further embodiments include: an obturator having a distal tip with a complementary geometry on the distal inner surface of the rigid elongated member that creates a seamless internal and external interface with the rigid elongated member in a contracted state (which requires less force to penetrate tissue and completely penetrate the fascial layer compared to conventional fixed diameter trocars and obturators; the tip shape may be blunt, sharp, or have a Veress needle); In one embodiment, the distal regions of the elongate rigid members together form a seamless, closed tip, allowing the expandable cannula device to be used without an obturator; a sealing resilient member around the device that creates a fluid seal within the cannula that prevents fluid communication between the lumen of the cannula and the external environment with and without the use of an instrument, the sealing resilient member being capable of having different geometric shapes and being assembled onto the elongated rigid member, the first and second housings in a variety of ways; an incision guide comprising a slot or blade on an elongated rigid member; an alternative expansion mechanism in which expansion of the elongated rigid member is actuated by a hinge system connecting the first housing to the elongated rigid member; a mount secured to an outer surface of the second housing that can be attached to an arm of a robotic surgical system with or without the ability of the mount to initiate expansion of the expandable cannula device using a mechanical mechanism; an embodiment of an expandable cannula device having a stopcock, a sealing resilient member, a one-way valve, and a backup valve that can prevent gas leakage with and without an instrument, and a constant diameter cannula shown with an array of holes, a backup valve, and a one-way valve that can also prevent gas leakage with and without an instrument, wherein the valve system and sealing resilient member of the expandable cannula device and the constant diameter cannula work together to prevent gas leakage from the entire device; For example, a constant diameter cannula containing a conical backup valve and one-way valve whose head can be separated from the distal cylindrical body via a latching mechanism to provide a full diameter open passageway for rapid degassing, which may be important during an emergency situation that may cause an embolism or if CO2 pressure is too high, or for specimen retrieval. Small and large instruments inserted through the cylindrical passage of the fixed diameter cannula while maintaining an airtight seal; and / or a dilation assembly having a non-vented obturator and a constant diameter cannula, which can be used as a cannula device in its own right and in a manner similar to a conventional trocar; may include one or more of:

[0022] According to one exemplary embodiment, a cannula device is provided that includes: a first housing defining a first throughbore aligned along a central axis; a second housing defining a second throughbore aligned with the first throughbore along the central axis, the second housing being axially movable along the central axis relative to the first housing; a plurality of elongate members cooperatively defining a passageway between proximal ends and distal tips of the elongate members that is axially aligned with the first throughbore along the central axis; and a plurality of guide elements on the proximal ends of the elongate members and the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly relative to the central axis and away from each other to increase the size of the passageway, the elongate members being configured such that when the proximal ends move radially outward, the distal tips are constrained, the elongate members define a tapered shape extending from the proximal ends toward the distal tips.

[0023] According to another exemplary embodiment, a cannula device includes a first housing defining a first throughbore aligned along a central axis, a second housing defining a second throughbore aligned with the first throughbore along the central axis, the first housing being axially movable along the central axis at least partially into the second throughbore of the second housing, a plurality of elongated members cooperatively defining a passageway between proximal and distal ends of the elongated members axially aligned with the first throughbore along the central axis, and a plurality of elongated members axially movable relative to the second housing along the central axis. A cannula device is provided that includes: a plurality of guide elements on the proximal ends of the elongated members and the first and second housings configured to cooperate so that axial movement of the housings causes the proximal ends of the elongated members to move outward relative to the central axis and away from each other, increasing the size of the passage; and a resistance member in the first housing adjacent an inlet communicating with the first through hole, the resistance member configured to receive a secondary device therethrough when the secondary device is inserted into the inlet and the first through hole and to couple the axial movement of the first housing to the axial movement of the secondary device.

[0024] According to yet another embodiment, a cannula device for use with an obturator includes an elongate shaft defining an outer diameter and an obturator tip at a distal end of the shaft having a cross section larger than the outer diameter, the cannula device including: a first housing defining a first throughbore aligned along a central axis; a second housing defining a second throughbore aligned with the first throughbore along the central axis, the first housing being axially movable along the central axis relative to the second housing; and a plurality of elongate members, each of which is axially movable between the proximal end and distal tip of the elongate members and the first throughbore along the central axis. A cannula device is provided that includes a plurality of elongate members that cooperatively define a passageway aligned in a axial direction, and a plurality of guide elements on the proximal ends of the elongate members and the first and second housings that are configured to cooperate so that axial movement of the first housing relative to the second housing along a central axis causes the proximal ends of the elongate members to move outward relative to the central axis and away from each other, increasing the size of the passageway, and the distal tips of the elongate members include an internal taper from the passageway to the outlet of the elongate members that is sized to receive a portion of the obturator tip when the shaft is positioned within the passageway.

[0025] According to yet another embodiment, a cannula device includes a first housing defining a first throughbore aligned along a central axis, a second housing defining a second throughbore aligned with the first throughbore along the central axis, the first housing being axially movable along the central axis relative to the second housing, and a plurality of elongate members cooperatively defining passages between proximal and distal ends of the elongate members axially aligned with the first throughbore along the central axis, wherein axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly relative to the central axis to expand. and a plurality of guide elements on the proximal ends of the first and second housings, the guide elements being configured to cooperate to move away from one another to a tensioned configuration and increase the size of the passageway, wherein longitudinal side edges of the elongated members are disposed adjacent to one another to surround the passageway when the first and second housings are in a first position before the elongated members are moved outwardly, and the side edges are disposed away from one another when the first and second housings are in a second position in which the elongated members are moved away from one another to increase the size of the passageway, and distal tips of the elongated members are tapered inward to surround the passageway in the first position.

[0026] According to yet another embodiment, there is provided a cannula device including: a first housing defining a first throughbore aligned along a central axis; a second housing defining a second throughbore aligned with the first throughbore along the central axis, the first housing being axially movable along the central axis relative to the second housing; a plurality of elongate members cooperatively defining a passageway between proximal ends and distal tips of the elongate members axially aligned with the first throughbore along the central axis; a plurality of guide elements on the proximal ends of the elongate members and the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly and away from each other relative to the central axis to increase the size of the passageway; and a membrane overlying the elongate members from the proximal ends at least partially toward the distal tips to provide a fluid-tight seal to prevent gas within the passageway from escaping between the elongate members.

[0027] According to yet another embodiment, there is provided a cannula device including: a first housing defining a first throughbore aligned along a central axis; a second housing defining a second throughbore aligned with the first throughbore along the central axis, the first housing being axially movable along the central axis relative to the second housing; a plurality of elongated rigid members cooperatively defining passageways between proximal ends and distal tips of the rigid members axially aligned with the first throughbore along the central axis; and a plurality of linkages on the proximal ends of the rigid members and the first housing configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the rigid members to move outwardly and away from each other relative to the central axis, increasing the size of the passageways.

[0028] According to yet another embodiment, a cannula device is provided that includes: a first housing defining a first throughbore aligned along a central axis; a second housing defining a second throughbore aligned with the first throughbore along the central axis, the first housing being axially movable along the central axis relative to the second housing; and a plurality of elongate members that cooperatively define passageways between proximal and distal ends of the elongate members that are axially aligned with the first throughbore along the central axis, wherein the elongate members and a plurality of guide elements on the proximal ends of the first and second housings are configured to cooperate such that axial movement of the first housing in a first direction relative to the second housing along the central axis moves the proximal ends of the elongate members outward and away from each other relative to the central axis to increase the size of the passageway; and after dilating the passageway, axial movement of the first housing in a second direction opposite the first direction moves the proximal ends of the elongate members inward to decrease the size of the passageway.

[0029] According to another exemplary embodiment, a system for introducing one or more instruments into a patient's body to perform a procedure is provided, the cannula device comprising: a. first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; b. a plurality of elongated members extending distally from the first and second housings, the elongated members cooperatively defining passages axially aligned with the throughbore along the central axis between proximal ends and distal tips of the elongated members; and c. axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongated members to move outwardly relative to the central axis and away from one another. a cannula device including a proximal end of an elongate member and a plurality of guide elements on the first and second housings configured to move in a direction perpendicular to the passageway and cooperate to increase the size of the passageway, wherein the distal tip of the elongate member includes an interior that tapers from the passageway to the outlet of the elongate member so that the outlet has a diameter larger than the passageway; and an obturator including: a. an elongate shaft configured to be inserted through the throughbore into the passageway and defining an outer diameter; and b. an obturator tip at the distal end of the shaft having a cross-section larger than the outer diameter, the taper of the distal tip being sized to receive a portion of the obturator tip when the shaft is positioned within the passageway.

[0030] According to yet another exemplary embodiment, a system for introducing one or more instruments into a patient's body to perform a procedure is provided, the cannula device comprising: a. first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; b. a plurality of elongated members extending distally from the first and second housings, the elongated members cooperatively defining passages axially aligned with the throughbore along the central axis between proximal ends and distal tips of the elongated members; and c. axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongated members to move relative to the central axis. a proximal end of the elongate member and a plurality of guide elements on the first and second housings configured to cooperate to move outward relative to the first housing and move away from each other to increase the size of the passageway, a distal tip of the elongate member having an interior tapered from the passageway to an outlet of the elongate member such that the outlet has a diameter larger than the passageway, and a secondary device sized for insertion into the passageway through the throughbore, the secondary device configured to engage the first housing to move the first housing distally relative to the second housing to move the elongate members away from each other and increase the size of the passageway.

[0031] According to yet another embodiment, a system for introducing one or more instruments into a patient's body to perform a procedure is provided, the cannula device comprising: a. first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; b. a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining a passageway axially aligned with the throughbore along the central axis between proximal and distal ends of the elongate members; and c. proximal ends of the elongate members configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outward and away from each other relative to the central axis, increasing the size of the passageway. A system is provided that includes a cannula device including a cannula device having a first housing and a second housing, a plurality of guide elements on the first and second housings, an obturator removably received through the through hole and passage with the rigid member at a reduced profile so that the distal tip of the obturator extends beyond the distal end of the elongated member, the distal tip of the obturator being sharpened to pierce tissue and create an entry hole in the subject's body to facilitate insertion of the cannula device through the tissue, and a set of secondary members sized for insertion through the through hole and into the passage, each secondary member configured to engage the first housing to move the first housing distally relative to the second housing, move the elongated members away from each other, and increase the size of the passage.

[0032] According to yet another embodiment, a system for introducing one or more instruments into a patient's body to perform a procedure is provided, the cannula device comprising: a. first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing, one of the first and second housings including a side port in communication with the throughbore such that a pressurized gas source connected to the side port can deliver gas into the throughbore through one or more openings; b. a plurality of elongated members extending distally from the first and second housings, the elongated members defining passages axially aligned with the throughbore along the central axis between proximal and distal ends of the elongated members; A system is provided that includes a cannula device including: c. a plurality of guide elements on the proximal ends of the elongated members and the first and second housings that cooperate to define a passageway; and c. a plurality of guide elements on the proximal ends of the elongated members and the first and second housings that cooperate to cause axial movement of the first housing relative to the second housing along the central axis to move the proximal ends of the elongated members outwardly relative to the central axis and away from each other, increasing the size of the passageway; and an elongated tubular member having a proximal end, a distal end sized for insertion into the passageway through the through hole, and a lumen extending between the proximal and distal ends, the tubular member having one or more openings in its side wall that communicate with the lumen so that pressurized gas introduced from the side port passes through the one or more openings and enters the lumen.

[0033] According to another exemplary embodiment, a method of performing a medical procedure within a subject's body is provided, comprising: connecting a cannula device to an arm of a robotic surgical system, the cannula device comprising first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing, a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passageways axially aligned with the throughbore along the central axis between proximal and distal ends of the elongate members; inserting the distal tips of the elongate members with the arm into the subject's body through tissue; expanding the cannula device by moving the first housing relative to the second housing along the central axis, thereby moving the proximal ends of the elongate members outwardly relative to the central axis and moving the elongate members away from each other to increase the size of the passageways; and introducing one or more instruments through the expanded cannula device to perform the medical procedure within the subject's body.

[0034] The features described herein below can be better understood in light of the detailed description of the exemplary embodiments.

[0035] Other aspects and features of the present invention will become apparent from consideration of the following detailed description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0036] The present invention is best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, in accordance with common sense, the various features and design elements in the drawings are not drawn to scale. Conversely, the dimensions of the various features and design elements have been arbitrarily expanded or reduced for clarity. The drawings include the following figures:

[0037] [Figure 1]1A-1D are isometric and side cross-sectional views of an example of an expandable cannula device in an initial (contracted) state (FIGS. 1A and 1C) and an expanded state (FIGS. 1B and 1D). [Figure 2] 2A-2F are side cross-sectional views of an expandable cannula device in which the proximal region of the elongated rigid member is first expanded to create a lumen of a larger cross-section than the distal region, allowing the expansion assembly to be inserted with less force, thereby expanding the distal region of the lumen. [Figure 3] 3A-3F are side cross-sectional views of the device of FIGS. 2A-2F, but shown inverted, illustrating removal of the expansion assembly and subsequent retraction of the expanded cannula. [Figure 4] 4A-4F are side cross-sectional views of another example of an expandable cannula device having a resistance member sealed within a first housing that also serves as a backup valve. These figures show the expansion assembly engaging the resistance member, which in turn engages the expansion mechanism shown in the previous figures. [Figure 5] 5A-5E are side cross-sectional views of the device of FIGS. 4A-4F, but shown inverted, illustrating the automatic retraction of the expanded cannula as a result of removal of the expansion assembly and subsequent engagement with the resistance member. [Figure 6] 6A-6E are side cross-sectional views of the expandable cannula of FIGS. 4A-4F in which, by engaging the resistance member with the expansion assembly, the proximal region of the elongated rigid member expands, creating a larger cross-sectional lumen than the distal region, allowing for less forceful insertion of the expansion assembly, which itself expands the distal region of the lumen. [Figure 7] 7A-7D are side cross-sectional views of the device shown in FIGS. 6A-6E, but shown inverted, illustrating the automatic retraction of the expanded cannula as a result of removal of the expansion assembly and subsequent engagement with the resistance member. [Figure 8]8A-8E are side cross-sectional views of an alternative embodiment of an expandable cannula device similar to the device shown in FIGS. 6A-6E, in which the resistance member includes a plurality of rigid strips that, when engaged with an expansion assembly, behave in a manner similar to the resistance member shown in FIGS. 6A-7D. [Figure 9] 9A-9D are cross-sectional side views of the device of FIGS. 8A-8E, but shown inverted, illustrating removal of the expansion assembly and subsequent retraction of the expanded cannula. [Figure 10] 10A-10E are side cross-sectional views of another embodiment of an expandable cannula device including a taper in the distal tip that cooperates with the obturator so that when the obturator is fully inserted into the passageway of the cannula device, the obturator tip cooperates with the recess to create a seamless, smooth interface with the distal tip of the elongated rigid member, thus facilitating low-force entry into tissue. [Figure 11] 11A-11E are side cross-sectional and overall side views of an alternative method of inserting an obturator into a cannula device similar to that shown in FIGS. 10A-10E to create a seamless distal interface. [Figure 12] 12A-12D are side cross-sectional views illustrating the removal of the obturator from the expandable cannula device in the reverse order from that shown in FIGS. 10A-10E. [Figure 13] 13A-13C are side cross-sectional views of exemplary embodiments of obturator tips that may be provided on obturators used with the cannula devices of FIGS. 10A-11E. [Figure 14] 14A-14E are side cross-sectional views of an example of an "obturator-less" cannula device including multiple elongated rigid members with distal tips that form a seamless interface to facilitate insertion of a navigation element into the passageway of the device prior to expansion, with a constant diameter cannula shown inserted into the device showing the expanded configuration. [Figure 15]15A-15B are side cross-sectional views of an example of an expandable cannula device including first and second resilient sealing members covering the exterior surface of the cannula device in contracted and expanded states, and FIGURES 15C-15D are side cross-sectional views of an alternative embodiment in which the first resilient sealing member is assembled to the proximal region of the first housing using an O-ring approach to create an airtight seal. [Figure 16] 16A-16B are side cross-sectional views of an alternative embodiment of an expandable cannula device including first and second elastic sealing members covering the outer surface of the cannula device in contracted and expanded states, and a proximal section including a bellows-like feature. [Figure 17] 17A-17B are side cross-sectional views of one exemplary embodiment of an expandable cannula device including a single sealing resilient member. [Figure 18] 18A-18B are side cross-sectional and detail views of various embodiments of a "u-shaped" elongated rigid member in which the distal end of the sealing resilient member is protected within a groove of the "u-shaped" feature. [Figure 19] 19A-19B are side cross-sectional and detail views of various embodiments of a "u-shaped" elongated rigid member in which the distal end of the sealing resilient member is protected within a groove of the "u-shaped" feature. [Figure 20] 20A-20B are side cross-sectional and detail views of various embodiments of a "u-shaped" elongated rigid member in which the distal end of the sealing resilient member is protected within a groove of the "u-shaped" feature. [Figure 21] 21A-21B are side cross-sectional and detailed views, respectively, of an alternative embodiment including an elongated rigid member including a distal-most ridge that is larger than proximal ridges spaced apart along the length of the rigid member to create a proximal surface to which the distal end of the elastic sealing member is attached and which is protected from direct contact with tissue. [Figure 22] 22A-22D are cross-sectional views of various alternative configurations for a "u-shaped" elongated rigid member. [Figure 23] 23A-23D are cross-sectional views of various alternative configurations for a "u-shaped" elongated rigid member. [Figure 24] 24A-24D are cross-sectional views of various alternative configurations for a "u-shaped" elongated rigid member. [Figure 25] 25A-25B are cross-sectional views of various alternative configurations for a "u-shaped" elongated rigid member. [Figure 26] 26A-26D show side and front views of one exemplary embodiment of a "u-shaped" elongated rigid member having an incision creation guide. [Figure 27] 27A-27D are side and front views of one exemplary embodiment of a "u-shaped" elongated rigid member for an expandable cannula device having blades for widening an incision in tissue when the cannula device is expanded. [Figure 28] 28A-28E are side and front views of an alternative embodiment of a "u-shaped" elongated rigid member having a blade and a protective cover. [Figure 29] 29A-29D are side cross-sectional and plan views of another embodiment of an expandable cannula device in which the elongated rigid member is radially guided within the second housing and connected to the first housing via a linkage or hinge that allows movement of the first housing relative to the second housing to initiate expansion and contraction of the cannula device. [Figure 30] 30A-30D show side, top, and isometric views of one exemplary embodiment of an expandable cannula device including the illustrated mount attached to a robotic arm for use with a robotic surgical system. [Figure 31] 31A-31F are side cross-sectional views of an alternative embodiment of an expandable cannula device attached to a robotic arm configured to actuate movement of a housing of the cannula device to expand and contract the expandable cannula device. [Figure 32]32A-32B are side cross-sectional views of an exemplary embodiment of an expandable cannula device including a side port with a stopcock, a sealing resilient member, a one-way valve, and a backup valve that collectively provide airtight protection during insufflation and desufflation of gases into an operable cavity of a subject into which the device is introduced and when instruments are inserted into the lumen of the expandable cannula device. FIGURES 32C-32D are side cross-sectional views of an exemplary embodiment of a constant diameter cannula including a one-way valve, a backup valve, and an array of holes that allow for insufflation and desufflation of gases when the constant diameter cannula is inserted into the lumen of the expandable cannula device. [Figure 33] 33A-33E are isometric and side cross-sectional views of one embodiment of an expandable cannula device in its expanded state with a constant diameter cannula inserted therein, showing the one-way valve and backup valve of the constant diameter cannula housed within a removable housing that can be removed for rapid gas degassing or specimen retrieval through the lumen of the constant diameter cannula. [Figure 34] 34A-34D are side cross-sectional views of an exemplary embodiment of an expandable cannula device in an expanded state with a constant diameter cannula, in which instruments of different diameters are inserted and manipulated at different angles within the lumen of the constant diameter cannula, and the expandable cannula device and constant diameter cannula cooperatively prevent loss of gas from its lumen. [Figure 35] 35A-35D are side and cross-sectional views of an alternative exemplary embodiment of a constant diameter cannula and obturator without holes in the wall of the constant diameter cannula, allowing the component to be used as a conventional trocar or a conventional optical trocar. DETAILED DESCRIPTION OF THE INVENTION

[0038] Before describing exemplary embodiments, it is to be understood that this invention is not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims.

[0039] Where a range of values ​​is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limits of that range, unless the context clearly dictates otherwise, is also specifically disclosed. Each smaller range between any stated or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the scope of the invention. The upper and lower limits of these smaller ranges may independently be included or excluded within the range, and each range in which either limit, neither limit, or both limits are included within the smaller range is also encompassed within the scope of the invention, subject to any specifically excluded limits in the stated range. When a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, some potential and exemplary methods and materials are now described.

[0041] It should be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a compound" includes a plurality of such compounds, reference to "a polymer" includes reference to one or more polymers and equivalents thereof known to those skilled in the art, and so forth.

[0042] Throughout the detailed description, references to an "upper" movement or position generally refer to a proximal movement or position. Similarly, references to a "lower" movement or position generally refer to a distal movement or position. Additionally, some references to the term "vertical" may mean axial, and vice versa, as can be discerned from the reference figures.

[0043] 1A-1D, an exemplary embodiment of an expandable cannula device 100 is shown, in which a system of a cylindrical first housing 1100, a plurality of elongated rigid members 1300, and a second housing 1200 are operatively connected such that certain axial movements cause the components to remove relative to one another to expand a passageway of the expandable cannula device 100 for use as an access port in a surgical environment.

[0044] With particular reference to FIGS. 1A and 1B, expandable cannula device 100, as shown in FIGS. 1B and 1D, includes a cylindrical first housing 1100 defining a first throughbore 1110, a plurality of elongated rigid members 1300 connected to first housing 1100 and cooperatively defining a passageway / lumen 1340 axially aligned with first throughbore 1110, and a cylindrical second housing 1210 defining a second throughbore 1210. 1. An exemplary embodiment of expandable cannula device 100 is shown, comprising: first housing 1100, elongated rigid members 1300, and second housing 1200 axially movable relative to first housing 1100, where second housing 1200 is operatively connected to elongated rigid members 1300 such that axial movement of second housing 1200 relative to first housing 1100 moves elongated rigid members 1300 away from one another, increasing the cross-sectional area of ​​passageway 1350. Axial movement of second housing 1200 in the opposite direction relative to first housing 1100 moves elongated rigid members 1300 closer to one another, decreasing the cross-sectional area of ​​passageway 1340.

[0045] In this embodiment, the first housing 1100 and the second housing 1200 are axially aligned with one another, although in alternative embodiments they need not be cylindrical in shape. For example, the first housing 1100 or the second housing 1200 or both may be rectangular, triangular, or polygonal in shape.

[0046] In some embodiments, the second housing 1200 surrounds the first housing 1100 and is axially guided by a plurality of tongues 1120 in the outer surface of the first housing 1100 and a plurality of complementary grooves 1220 on the inner surface of the second housing 1200. The plurality of tongues 1120 and grooves 1220 allow only one axis of movement to occur between the first housing 1100 and the second housing 1200. The first housing 1100 and the second housing 1200 can be made of reinforced plastic, which can be injection molded.

[0047] In alternative embodiments, the plurality of tongues 1120 and grooves 1220 can be in the form of a single tongue in the second housing 1200 and a single complementary groove in the first housing 1100 (or vice versa), the complementary shapes comprising a lock and key mechanism, or optionally having multiple tongues in the first housing 1100 and multiple complementary grooves in the second housing 1200, or having extruded flat surfaces in the second housing 1200 and complementary extruded cut surfaces in the first housing 1100 (or vice versa), or other guide mechanisms and designs known in the art. Further examples of guide elements that may be provided on the housings 1100, 1200 and / or the elongated rigid member 1300 can be found in International Publication WO 2019 / 046940, the entire disclosure of which is expressly incorporated herein by reference.

[0048] In alternative embodiments, the second housing 1200 may be made of two or more pieces that may be attached together to surround the first housing 1100 .

[0049] 1C and 1D , in some embodiments, the plurality of elongated rigid members 1300 includes distal inner and outer surfaces 1311, 1312, a proximal diagonal rail 1321, and a distal horizontal rail 1322 perpendicular to the longitudinal axis of the elongated rigid member 1300, the diagonal rail 1321 being complimentary to the diagonal groove 1130 in the first housing 1100, and the horizontal rail 1322 being complimentary to the horizontal groove 1230 in the second housing 1200. The distal inner surface 1311 of the plurality of elongated rigid members 1300 defines the cross-sectional area of ​​the cannula passageway 1340.

[0050] The elongated rigid member 1300 should be made of a durable material with high tensile strength, such as stainless steel or plastic, so that it cannot be fractured by external radial and torsional forces. For example, the elongated rigid member 1300 can be substantially rigid axially between its proximal and distal ends so that it has sufficient column strength to facilitate introduction of the distal tip into a subject's body. Optionally, the elongated rigid member 1300 can be semi-rigid radially so that the elongated rigid member 1300 is locally deflectable perpendicular to the central axis, as described elsewhere herein, for example, to allow the elongated member to define a tapered shape and / or to accommodate a relatively larger obturator tip to be introduced between the elongated rigid members 1300.

[0051] In some embodiments, the outer surface 1312 of the elongate rigid member 1300 can have surface modifications 1313, such as extrusions in the form of ridges or peaks and / or other features spaced apart from one another along the length of the elongate rigid member 1300, which can improve retention of the expandable cannula device 100 within tissue. In alternative embodiments, there can be more than one elongate rigid member 1300, although only two are shown in this embodiment for simplicity of explanation.

[0052] A conventional Cartesian coordinate system is shown to describe the relative movement of the rightmost elongated rigid member 1300 and the first housing 1100 shown in cross-sectional views 1C-1D. For purposes of explanation, the second housing 1200 is fixed in motion relative to the origin of the coordinate system, and the movement of the rightmost elongated rigid member 1300 and the first housing 1100 is relative to the second housing 1200. However, it will be understood by those skilled in the art that any combination of relative motion is possible in this context (e.g., the second housing moves relative to a fixed first housing). In this embodiment, the first housing 1100 is concentric with the second housing 1200, the first housing 1100 moves vertically in the ±z directions, and the rightmost elongated rigid member 1300 moves horizontally in the ±x directions.

[0053] This coordinate system will be referred to in other descriptions and figures in subsequent sections and will refer to the rightmost rigid elongate member 1300 in such figures and cross-sectional views, respectively, such that the second housing 1200 remains fixed relative to the origin of the coordinate system. Because the movements of the other rigid elongate members 1300 are similar but in various radial directions about the central axes of the expandable cannula device 100 and the rightmost rigid elongate member 1300, their movements will not be described in sufficient detail that one skilled in the art can apply the same principles to understand them.

[0054] The diagonal rail 1321 of the elongated rigid member 1300 is shown received within the diagonal groove 1130 of the first housing 1100, and the horizontal rail 1322 of the elongated rigid member 1300 is shown received within the horizontal groove 1230 of the second housing 1200. The material between the diagonal rail 1321 and the horizontal rail 1322 of the elongated rigid member 1300 is rigid such that they always maintain the geometric shape shown and a constant distance from each other. For example, the rightmost edge of the horizontal rail 1322 is always vertically displaced a constant amount from the rightmost edge of the diagonal rail 1321. The distal region 1310 of the elongated rigid member 1300 is also shown to be just distal to the horizontal rail 1322, and the entire elongated rigid member and all of its features are made from solid material such that movement of one feature of this portion along the z-axis or x-axis implies movement of the entire elongated rigid member 1300.

[0055] When a vertical force in the -z direction is applied to the first housing 1100 while it is within the second housing 1200, it causes the first housing 1100 to move downward (distal) in the -z direction, displacing it downward (distal) from its initial position. Because the diagonal rail 1321 is housed within the first housing 1100 and must simultaneously maintain a certain distance away from the horizontal rail 1322, the vertical displacement of the first housing 1100 in the -z direction causes the diagonal rail 1321 to slide diagonally outward along the diagonal groove 1130 of the first housing 1100. At the same time, because the diagonal rail 1321 of the elongated rigid member 1300 is spaced a certain distance from the horizontal rail 1322, this diagonal outward movement causes the horizontal rail 1322 to slide horizontally outward in the +X direction within the horizontal groove 1230. This causes the entire rigid elongate member 1300 to move outward relative to its initial position, thus increasing the cross-sectional area of ​​the passageway created by the inner distal surface 1311 of the rigid elongate member 1300 and widening the passageway 1350 of the expandable cannula device 100. The combination of these effects also creates a cam follower mechanism or a double cam follower mechanism.

[0056] FIG. 1D shows that the second housing 1200 remains fixed at the origin while the first housing 1100 is displaced in the −z direction relative to the second housing 1200 to its farthest distal position and the right elongated rigid member 1300 is displaced in the +x direction relative to the second housing 1200 to its rightmost position.

[0057] The effects described herein occur simultaneously for the other elongated members 1300 shown in these figures, but it will be understood by those skilled in the art that describing each in this or a different coordinate system is an iterative exercise. As a simple example, the leftmost rigid elongated member 1300 is moving in the -x direction using the above coordinate system.

[0058] When the device is expanded, applying a normal force to the first housing 1100 in the +z direction causes a set of opposing movements, thus contracting the elongated rigid members 1300 inward and closer to each other, thus reducing the cross-sectional area of ​​the passage created by the distal inner surface 1311 of the elongated rigid members 1300 and contracting the expanded cannula 100.

[0059] In alternative embodiments, the size and shape of the diagonal rail 1321, diagonal groove 1130, horizontal rail 1322, and horizontal groove 1230 may be different, as long as their geometries are complementary to allow for smooth movement. The angle of the diagonal rail 1321 of the plurality of elongated rigid members 1300 and the angle of the diagonal groove 1130 in the first housing 1100 can also be increased or decreased to vary the vertical movement speed of the first housing 1100 within the second housing 1200, and therefore the expansion / contraction speed of the plurality of elongated rigid members 1300. Varying the expansion / contraction speed can improve surgical workflow, especially in emergency situations requiring larger instruments to be inserted into the cannula device. It also allows for quicker and easier removal of the expandable cannula device after surgery.

[0060] In this embodiment, a downward (distal) or upward (proximal) normal force applied to the first housing 1100 at a given time interval can control the amount of expansion or contraction by controlling the cross-sectional area of ​​the passageway created by the distal inner surface 1311 of the elongated rigid member 1300, thereby expanding or contracting the passageway 1350 of the expandable cannula device 100.

[0061] Furthermore, the expansion and contraction described herein occurs in a smooth, continuous, analogous manner (i.e., from inner diameter A to inner diameter B), not in a finite or stepped manner, as would be understood by one of ordinary skill in the art.

[0062] In alternative embodiments, the height and inner and outer cross-sectional areas of the first housing 1100 and the second housing 1200 can be increased or decreased to accommodate changes in the angle of the plurality of diagonal grooves 1130 in the first housing 1100 or changes in the inner and outer cross-sectional areas of the required passageways. In alternative embodiments, the height and / or outer cross-sectional area of ​​the first housing 1100 and the second housing 1200 can remain the same and can accommodate changes in the angle of the plurality of diagonal grooves 1130 in the first housing 1100.

[0063] 2A-2F show an exemplary method of using the expandable cannula device 100 (shown in FIGS. 1A-1D) in which vertical movement of the first housing 1100 relative to the second housing 1200 causes the proximal regions 1320 of the elongate rigid members 1300 to move away from each other, creating a larger proximal cross-sectional lumen 1361, allowing the expansion assembly 1500 to be inserted to expand the expandable cannula device 100 for use in a surgical environment.

[0064] 2A-2B , vertical movement of first housing 1100 relative to second housing 1200 causes proximal regions 1320 of elongate rigid member 1300 to move away from one another, creating a larger proximal cross-sectional lumen 1361, while distal regions 1310 of elongate rigid member 1300 remain closer together with a smaller distal cross-sectional lumen 1362, creating a gradually tapered lumen 1360 (or gradually tapered conical lumen 1360) throughout passageway 1360, with gradually tapered lumen 1360 comprising a larger proximal cross-sectional lumen 1361 and a smaller distal cross-sectional lumen 1362. The effect of gradually tapered lumen 1360 can occur when elongate rigid member 1300 is subjected to pressure from surrounding tissue or an external member (e.g., sealing resilient member 1740, described in a subsequent section). This is particularly likely when the rigid elongated member is made of a hard but flexible plastic or metal that can bend or deflect like a cantilever when subjected to external pressure. Nevertheless, this mechanism creates an internal passageway within the rigid elongated member 1300 of the cannula device 100 having a tapered conical shape 1360 that allows for smoother entry of the large expansion assembly 1500 into the expandable cannula device 100 with less force by avoiding direct contact with the proximal portion of the rigid elongated member 1300. The reduced friction of the expansion assembly 1500 with the rigid elongated member 1300 during its entry reduces the large, uncontrollable force required by the user to otherwise overcome frictional resistance. With other devices described in the existing art, this excessive force could cause serious harm or injury to the patient, or could accidentally break the device and / or puncture the patient's tissue.

[0065] In this embodiment, an external force is applied onto the outer surface 1312 of the elongate rigid member 1300. This can occur when the expandable cannula device 100 is inserted into resilient tissue, which applies a force to the outer surface 1312 of the distal region 1310 of the elongate rigid member 1300, causing the distal passage cross-sectional area 1362 to remain smaller than the proximal passage cross-sectional area 1361.

[0066] As previously discussed, with reference to the coordinate system of FIG. 1C and the rightmost elongated rigid member 1300 shown in this cross-sectional view, a vertical force in the -z direction applied to the first housing 1100 within the second housing 1200 will cause the first housing to move downward (distally) in the -z direction, and the vertical force in the -z direction will cause the rightmost elongated rigid member 1300 to move outward to the right in the +x direction, with the diagonal rails 1321 of the elongated rigid member 1300 moving outward along the diagonal grooves 1130 in the first housing 1100 and the horizontal rails 1322 moving outward along the horizontal grooves 1230 in the second housing 1200. The plurality of elongated rigid members 1300 results in a proximal region of the inner surface 1323 of the elongated rigid member 1300 creating a larger passage cross-sectional area 1361 than the distal inner surface 1311 of the elongated rigid member 1300, indicated by a gradual taper of decreasing cross-sectional area (internal conical taper) 1360 throughout the passage.

[0067] In an alternative embodiment, expandable cannula device 100 can have a resilient covering (e.g., sealing resilient member 1740 described in a subsequent section) surrounding elongated rigid member 1300 and second housing 1200, which can apply a force to the outer surface of the distal region of elongated rigid member 1300, causing distal passage cross-sectional area 1362 to remain smaller than proximal passage cross-sectional area 1361. In an alternative embodiment, expandable cannula device 100 can have a resilient covering and can be inserted into tissue.

[0068] 2C , in this exemplary embodiment, the expansion assembly 1500 includes an obturator 1510 having an obturator head, handle, or hub 1511 and a distal tip 1513, and a constant diameter cannula 1520 having a head, handle, or hub 1535, such that the obturator 1510 can be inserted and removed from the constant diameter cannula 1520, and the entire expansion assembly 1500 can be inserted into the expandable cannula device 100. The purpose of inserting the constant diameter cannula 1520 into the passageway of the expanded cannula device 100 is to create a completely enclosed lumen inside the expansion region created by the rigid elongate member 1300. This completely enclosed lumen of the constant diameter cannula 1520 allows for the safe passage of instruments from the intermediate space of the expanded rigid elongate member 1300 into the patient without the possibility of such instruments penetrating the patient's tissue. In this embodiment, the expansion assembly 1500 is inserted downward (distally) through the passageway 1340 created by the through-hole 1110 of the first housing 1100 and the distal inner surface 1311 of the elongate rigid member 1300. The distal tip 1513 of the obturator 1510 in the expansion assembly 1500 initiates contact with the distal inner surface 1311 of the elongate rigid member 1300 at the distal region of the conical taper 1362, expanding the distal region 1310 of the elongate rigid member 1300 such that the distal inner surface 1311 of the elongate rigid member 1300 surrounds the expansion assembly 1500. It will be understood by those skilled in the art that because the contact area between the expansion assembly 1500 and the distal inner surface 1311 of the elongate rigid member 1300 is minimized by the inner taper 1360, less force is required to expand the distal region 1310 of the elongate rigid member 1300 than would be required if the inner taper 1360 were not created.

[0069] In alternative embodiments, the cross-sectional area of ​​the expansion assembly 1500 may be larger or smaller than that shown, ranging in diameter from 2.5 mm (or less) to greater than 15 mm to accommodate a variety of instruments, including various sizes. The constant diameter cannula 1520 may have an angled cut at its distal end, which is flush with the obturator 1510 to reduce the resistance of the constant diameter cannula 1520 during insertion into the expandable cannula 100.

[0070] In an alternative embodiment, the elongated rigid members 1300 may be made of flexible plastic, allowing them to be tapered only in the proximal region and not in the distal region 1310, and the expansion assembly 1500 causes the elongated rigid members 1300 to expand only when the distal tip 1513 of the expansion assembly 1500 passes through the respective axial cross-sectional area of ​​the elongated rigid members 1300.

[0071] In alternative embodiments, the obturator 1510 and constant diameter cannula 1520 can be made from a variety of different materials that have high tensile strength, such as injection molded plastic or metal, and will not break under high pressure.

[0072] With particular reference to FIG. 2D , in this exemplary embodiment, the expansion assembly 1500 is fully inserted as indicated by the distal surface of the head 1522 contacting the proximal surface 1140 of the first housing 1100, causing the elongated rigid member 1300 to straighten and no longer tapered.

[0073] In other embodiments, the expanded cannula device 100 can be used to be placed into the patient like a conventional trocar.

[0074] In alternative embodiments, the distal tip 1513 of the obturator 1510 may have a different shape and / or configuration, for example, a sharp or bladed tip or a blunt tip with different taper angles, and / or the obturator 1510 may be hollow. In other embodiments, the hollow obturator 1510 may have an optically clear tip 1513 and can be used as a conventional optical obturator for use with an endoscope.

[0075] 2E-2F, in this exemplary embodiment, the obturator 1510 is removed from the constant diameter cannula 1520 to allow an instrument to be inserted through the hollow passage 1521 within the constant diameter cannula 1520. The obturator 1510 is removed by applying a normal force upward (proximally) to the distal face 1512 of the obturator head 1511 such that the constant diameter cannula 1520 remains in place within the expandable cannula by the elongated rigid member 1300.

[0076] In an alternative embodiment, a valve system may be provided including one or more seals and / or valves, for example, a one-way valve 1190 and / or resistance member 1610 (further described elsewhere herein) located within a proximal region of the through hole 1110 in the first housing 1100 to prevent gas loss through the first housing 1100 during the procedure.

[0077] 3A-3F, the operation of the expandable cannula device 100 described above (of FIG. 2) is shown in reverse, in that the same mechanism that expands the elongated rigid member 1300 can also be used to contract / retract / compress the elongated rigid member 1300 back to its minimum cross-sectional area.

[0078] With particular reference to Figures 3A-3C, in this exemplary embodiment, the obturator 1510 is reinserted through a constant diameter cannula 1520 located within the expandable cannula device 100, which is surrounded by the expanded elongated rigid member 1300.

[0079] With particular reference to Figures 3D-3E, the obturator 1510 and constant diameter cannula 1520 are simultaneously removed by applying an upward (proximal) force to the distal face of the constant diameter cannula head 1522, also moving the elongated rigid member 1300 starting at the distal region 1310 together and creating a gradually tapered lumen 1360 (or a gradually tapered conical lumen 1360) after the distal tip 1513 of the obturator 1510 as the expansion assembly 1500 is removed.

[0080] The distal surface 1150 of the first housing 1100 remains close to the inner proximal surface 1260 of the second housing 1200, the horizontal rail 1322 of the elongated rigid member 1300 remains horizontally outwardly facing (the elongated rigid member 1300 to the right in the +x direction) within the horizontal groove 1230 in the second housing 1200, and the proximal region 1361 of the distal inner surface 1311 of the elongated rigid member 1300 maintains a larger passage cross-sectional area than the distal region 1362 of the contracted elongated rigid member 1300, as indicated by the gradual conical taper that reduces the cross-sectional area 1360 throughout the passage.

[0081] 3F , and with particular reference to the coordinate system of FIG. 1C and the right-most elongated rigid member 1300 shown in this cross-sectional view, the elongated rigid member 1300 is contracted to create a minimum internal passageway cross-sectional area 1340, and a normal force in the +z direction is applied to the first housing 1100 relative to the second housing 1200, causing the first housing to move upward (proximally) in the +z direction, and the right-most elongated rigid member 1300 to move inward to the left in the −x direction, with the diagonal rails 1321 of the elongated rigid member 1300 moving inward along the diagonal grooves 1130 in the first housing 1100 and the horizontal rails 1322 moving inward along the horizontal grooves 1230 in the second housing 1200. This reduces the cross-sectional area of ​​the passageway created by the distal inner surfaces 1311 of the plurality of elongated rigid members 1300, causing the passageway to contract. The expandable cannula device 100 can be removed from tissue at this small cross-sectional area 1340 in a manner that reduces damage.

[0082] In an alternative embodiment (not shown), the constant diameter cannula 1520 may be removed without the need for the obturator 1510 to be inserted first.

[0083] In an alternative embodiment, the expandable cannula device 100 is not deflated prior to removal from the tissue.

[0084] In an alternative embodiment, the expandable cannula device 100 can have an elastic cover (e.g., the sealing elastic member 1740 described in the section that follows) surrounding the elongated rigid member 1300 and the second housing 1200, the taut elastic cover exerting an inward force on the outer surface of the elongated rigid member 1300 and causing the elongated rigid member 1300 to contract as described above.

[0085] 4A-4F, another exemplary embodiment of expandable cannula device 100 (generally similar to that shown in FIGS. 1A-1F) is shown in which first housing 1100 includes resistance member 1610 and expansion assembly 1500 can initiate vertical movement of first housing 1100 relative to second housing 1200, thus causing elongated rigid members 1300 to move away from or toward each other. This mechanism can be used to improve safety by reducing the force required to insert the expansion assembly into first housing 1100 and the distal portion of the passageway, while also streamlining expansion in a one-stop process, which can be particularly useful during emergency situations requiring quick reaction and response.

[0086] 4A , in this exemplary embodiment, the first housing 1100 includes a resistance member 1610 concentrically housed in a rotation cavity 1160 within a proximal region of the through-hole 1110 above the highest point of the diagonal rail 1321 of the elongated rigid member 1300. The resistance member 1610 includes a backup valve, which is common in laparoscopic trocars on the market. It serves to reduce or prevent gas loss from the proximal end of the passageway through the through-hole of the first housing 1100 when instruments are inserted and manipulated through the unexpanded device shown in FIG. 4A . The resistance member 1610 (backup valve) is made of an elastic member having a concentric bore 1611 that can stretch to fit the expansion assembly 1500 therein and contract to return to its original bore cross-sectional area after the expansion assembly 1500 is removed, the concentric bore 1611 having a cross-sectional area smaller than the cross-sectional area of ​​the members and instruments inserted therethrough.

[0087] In one exemplary embodiment, the elastic member 1610 may be made of a thin polymer such as polyisoprene or silicone, which may be made from a sheet polymer into which holes 1611 can be punched. In an alternative embodiment, the resistance member 1610 may be in the form of a flexible, but non-stretchable member, valve, spring, or bracket. In an alternative embodiment, there may be more than one resistance member 1610. In an alternative embodiment, varying the geometry and material of the resistance member 1610 may change the rate and ease of expansion and contraction.

[0088] In an alternative embodiment, the cavity 1160 in which the resistance member 1610 is housed may be in the form of a rectangular cutout and may be located anywhere within the first housing 1100 above the diagonal groove 1130 .

[0089] With particular reference to FIG. 4B, in this exemplary embodiment, the expansion assembly 1500 engages the resistance member 1610 to effect vertical movement of the first housing 1100 relative to the second housing 1200, thus moving the elongated rigid members away from each other.

[0090] In this embodiment, the expansion assembly 1500 is guided toward the through-hole 1110 in the first housing 1100, the distal tip 1513 of the obturator 1510 applies a downward (distal) force to the resistance member 1610, the bore 1611 in the resistance member 1610 begins to expand to accommodate the increasing cross-sectional area of ​​the distal tip 1513 of the obturator 1510, and the material of the resistance member 1610 begins to stretch distally to create a partially expanded tapered passageway 1613. At the same time, because the resistance member 1610 is housed within the cavity 1160 in the proximal region of the first housing 1100, applying the downward (distal) force to the resistance member 1610 in the −z direction causes downward vertical movement of the first housing 1100 relative to the second housing 1200. This causes the rightmost elongated rigid member 1300 to move outward to the right in the +x direction, with the diagonal rail 1321 of the elongated rigid member 1300 moving outward along the diagonal groove 1130 in the first housing 1100 and the horizontal rail 1322 moving outward along the horizontal groove 1230 in the second housing 1200. The same outward movement occurs for the other elongated rigid members 1300, where they move away from each other, thus increasing the cross-sectional area of ​​the passageway created by the distal inner surfaces 1311 of the elongated rigid members 1300 and expanding the passageway 1350 of the expandable cannula device 100.

[0091] 4C-4D , as the expansion assembly 1500 is further inserted to its potential maximum cross-sectional area 1514, the hole 1611 in the resistance member 1610 expands to a cross-sectional area equal to the outer cross-sectional area of ​​the expansion assembly 1500, and material is stretched to a distal position 1614, at which point the horizontal rail 1322 and the diagonal rail 1321 of the elongate rigid member 1300 are displaced / expanded, and the cross-sectional area of ​​the passageway created by the distal inner surface 1311 of the elongate rigid member 1300 is expanded such that the passageway they create is large enough in cross-section to allow entry of the expansion assembly 1500. This creates an open passageway 1350 through which the expansion assembly 1500 can be inserted until the distal face of the constant diameter cannula head 1522 contacts the proximal face 1140 of the first housing 1100.

[0092] In an alternative embodiment, the same effect described above is produced using a constant diameter cannula 1520 alone and without an obturator 1510.

[0093] 4E-4F, in this exemplary embodiment, the obturator 1510 is separated from the constant diameter cannula 1520 to allow an instrument to be inserted through a hollow passage 1521 within the constant diameter cannula 1520. The obturator 1510 is removed by applying a normal force upward (proximally) to the distal face 1512 of the obturator head 1511 such that the constant diameter cannula 1520 remains in place by the elongated rigid member 1300.

[0094] 5A-5E, the previously described expandable cannula device 100 (of FIGS. 4A-4F) is shown operated in reverse, where the same mechanism that expands the elongated rigid member 1300 using the resistance member 1610 can be used to contract / compress the elongated rigid member 1300 back to its minimum cross-sectional area 1340.

[0095] With particular reference to FIGS. 5A-5B, in this exemplary embodiment, the obturator 1510 is reinserted through a constant diameter cannula 1520 located within the expandable cannula device 100, which is surrounded by the rigid elongate member 1300.

[0096] With particular reference to FIG. 5C , the obturator 1510 and constant diameter cannula 1520 begin to be removed simultaneously by applying an upward (proximal) force to the distal face of the constant diameter cannula head 1522, causing the resistance member 1610 to conform to the expansion assembly 1500 and extend proximally to create an opposing tapered passageway 1615.

[0097] With particular reference to FIG. 5D , when the distal tip 1513 of the obturator 1510 moves upward (proximally) in the +z direction through the hole 1611 in the resistance member 1610 and is no longer in contact with the distal inner surface 1311 of the elongated rigid member 1300, the cross-sectional area of ​​the hole 1611 in the resistance member 1610 shrinks to accommodate the tapered obturator tip 1513 being removed, at which point the first housing 1100 moves axially (vertically) upward (proximally) in the +z direction due to the upward (proximal) force created by the expansion assembly 1500 and the resistance member 1610 following the direction of the expansion assembly 1500, and the elongated rigid member 1300 move together again, reducing the cross-sectional area of ​​the passage created by the distal inner surface 1311 of the elongated rigid member 1300.

[0098] With particular reference to FIG. 5E, when the expansion assembly 1500 is completely removed, the resistance member 1610 contracts back to its original bore cross-sectional area and is no longer extended distally or proximally 1612, and the elongate rigid member 1300 contracts back to its minimum cross-sectional area 1340.

[0099] In another embodiment, the same effect described above can be produced by removing the constant diameter cannula 1520 alone and without the obturator 1510 to deflate the expandable cannula device 100 .

[0100] 6A-6E, the expandable cannula device 100 described above (of FIGS. 4A-4F) is shown in which the resistance member 1610 within the first housing 1100 and the expansion assembly 1500 can initiate vertical movement of the first housing 1100 relative to the second housing 1200, causing the inner surfaces 1323 of the proximal regions of the elongated rigid member 1300 to move away from each other, creating a larger proximal cross-sectional area 1361, while the distal regions of the elongated rigid member 1300 remain closer together with a smaller distal cross-sectional area 1362, creating a gradual conical taper of decreasing cross-sectional area 1360 throughout the passageway to initiate a smooth expansion.

[0101] With particular reference to Figures 6A-6C, as previously described, with respect to the coordinate system of Figure 1C and the rightmost elongated rigid member 1300 shown in this cross-sectional view, the expansion assembly 1500 is guided toward the through hole 1110 in the first housing 1100, the distal tip 1513 of the obturator 1510 applies a downward (distal) force to the resistance member 1610, the hole 1611 in the resistance member 1610 expands to correspond to the cross-sectional area of ​​the distal tip 1513 of the obturator 1510, and the material of the resistance member 1610 extends distally to create a fully expanded tapered passage 1614. At the same time, because the resistance member 1610 is housed within the cavity 1160 in the proximal region of the first housing 1100, applying a downward (distal) force to the resistance member 1610 in the -z direction causes a downward vertical movement of the first housing 1100 relative to the second housing 1200. This causes the rightmost elongated rigid member 1300 to move outward to the right in the +x direction, with the diagonal rail 1321 of the elongated rigid member 1300 moving outward along the diagonal groove 1130 in the first housing 1100 and the horizontal rail 1322 moving outward along the horizontal groove 1230 in the second housing 1200. A plurality of elongated rigid members 1300 follow, with the proximal region of the inner surface 1323 of the elongated rigid members 1300 creating a larger passage cross-sectional area 1361 than the distal inner surface 1311 of the elongated rigid members 1300, indicated by a gradual taper that reduces the cross-sectional area 1360 throughout the passage.

[0102] In an alternative embodiment, the expandable cannula device 100 may be inserted into tissue, and the tissue may apply a force to the outer surface 1312 of the distal region 1310 of the elongate rigid member 1300, causing the distal passage cross-sectional area 1362 to remain smaller than the proximal passage cross-sectional area 1361.

[0103] In an alternative embodiment, the expandable cannula device 100 can have an elastic cover surrounding the elongated rigid member 1300 and the second housing 1200, which can apply a force to the outer surface of the distal region of the elongated rigid member 1300, causing the passage cross-sectional area to remain smaller than the proximal passage cross-sectional area.

[0104] In an alternative embodiment, the expandable cannula device 100 has an elastic covering and is capable of being inserted into tissue.

[0105] As the expansion assembly 1500 is inserted further to the point of its potential maximum cross-sectional area 1514, the hole 1611 in the resistance member 1610 reaches its maximum cross-sectional area (equal to the outer cross-sectional area of ​​the expansion assembly 1500) and the material is stretched to a distal position 1614, at which point the horizontal rail 1322 and diagonal rail 1321 of the elongate rigid member 1300 are displaced from their contracted state and the cross-sectional area of ​​the passageway created by the distal inner surface 1311 of the elongate rigid member 1300 is expanded. This creates an open passageway 1350 through which the expansion assembly 1500 is inserted until the distal face of the constant diameter cannula head 1522 contacts the proximal face 1140 of the first housing 1100.

[0106] In an alternative embodiment, the same effect described above is produced using a constant diameter cannula 1520 alone and without an obturator 1510.

[0107] 6D-6E, in this exemplary embodiment, the obturator 1510 is separated from the constant diameter cannula 1520 to allow an instrument to be inserted through a hollow passage 1521 within the constant diameter cannula 1520. The obturator 1510 is removed by applying a normal force upward (proximally) to the distal face 1512 of the obturator head 1511 such that the constant diameter cannula 1520 remains in place by the elongated rigid member 1300.

[0108] 7A-7D, the previously described expandable cannula device 100 (of FIGS. 6A-6E) is shown operated in reverse, where the same mechanism that expands the elongated rigid member 1300 using the resistance member 1610 can also be used to contract / compress the elongated rigid member 1300 back to its minimum cross-sectional area.

[0109] With particular reference to FIGS. 7A-7B, in this exemplary embodiment, the obturator 1510 is reinserted through a constant diameter cannula 1520 located within the expandable cannula device 100, which is surrounded by the rigid elongate member 1300.

[0110] With particular reference to FIG. 7C , the obturator 1510 and constant diameter cannula 1520 begin to be removed simultaneously by applying an upward (proximal) force to the distal face of the constant diameter cannula head 1522, causing the resistance member 1610 to conform to the expansion assembly 1500 and extend proximally to create an opposing taper 1615.

[0111] As the distal tip 1513 of the obturator 1510 moves upward (proximally) in the +z direction through the hole 1611 in the resistance member 1610 and no longer contacts the distal inner surface 1311 of the elongate rigid member 1300, the cross-sectional area of ​​the hole 1611 in the resistance member 1610 contracts to correspond to the decreasing taper of the obturator distal tip 1513 being removed, at which point the first housing 1100 moves vertically upward (proximally) in the +z direction due to the upward (proximal) force created by the expansion assembly 1500 and the resistance member 1610 following the direction of the expansion assembly 1500. The proximal region of the inner surface 1323 of the elongate rigid member 1300 maintains a larger passage cross-sectional area than the distal region of the contracted elongate rigid member 1300, indicated by the gradual taper of the decreasing cross-sectional area 1360 throughout the passage.

[0112] With particular reference to FIG. 7D , when the expansion assembly 1500 is completely removed, the resistance member 1610 contracts back to its original bore cross-sectional area and is no longer extended distally or proximally 1612, and the elongate rigid member 1300 contracts back to its minimum cross-sectional area 1340.

[0113] In another embodiment, the same effect described above can be produced by removing the constant diameter cannula 1520 alone and without the obturator 1510 to deflate the expandable cannula device 100 .

[0114] In other embodiments, the functionality of the resistance member 1610 described in Figures 4A-7D may be achieved via a one-way valve 1190 or a combination of the resistance member 1610 and the one-way valve 1190, for example, as further described elsewhere herein.

[0115] 8A-8D, an alternative exemplary embodiment of the expandable cannula device 100 (generally similar to that shown in FIGS. 6A-6E) is shown, except that the resistive member 1600 includes at least one or more rigid strips 1620, which behave similarly to the flexible metal strips commonly found in battery cases, such as (negative lead contacts) or car power adapter heads.

[0116] With particular reference to FIG. 8A , in this embodiment, the rigid strip 1620 is bent into a horizontal U-shape, with the distal end 1621 pinned within the cavity 1160 in the proximal region of the through hole 1110 in the first housing 1100, and the proximal end 1622 being free to allow the rigid strip 1620 to deform under horizontal compression and to move radially outward toward the wall of the cavity 1160 in the first housing 1100 to expand the passage 1623 created by the rigid strip 1620, and when the compression is released, the rigid strip 1620 can return to its original shape and create the small passage 1623 created by the rigid strip 1620.

[0117] In this embodiment, the plurality of rigid strips 1620 are initially positioned such that the inner surfaces of the rigid strips 1620 form small passages 1623 within the through-holes 1110 of the first housing 1100 .

[0118] The rigid strip 1620 can be made of a rigid material that is not ductile so that it does not plastically deform but is still flexible.

[0119] In an alternative embodiment, the passageway created by the inner surfaces 1623 of the rigid strips 1620 can be any polygonal shape depending on the number of rigid strips 1620 .

[0120] 8b-8c, as previously described, with respect to the coordinate system of FIG. 1C, the rightmost elongated rigid member 1300 shown in this cross-sectional view, and particularly with respect to the rightmost rigid strip 1620, the expansion assembly 1500 is guided toward the through-hole 1110 in the first housing 1100, and the distal tip 1513 of the obturator 1510 exerts a downward (distal) force in the −z direction on the rigid strip 1620, which pushes the right rigid strip 1620 in the +x direction, deforming it horizontally and moving its free end 1622 radially outward toward the wall of the cavity in the first housing 1100. Each of the other rigid strips 1620 behaves similarly, thus fully expanding the passageway 1623 created by the rigid strip 1620 to accommodate the gradually increasing cross-sectional area of ​​the distal obturator tip 1513. At the same time, because the rigid strip 1620 is housed within the cavity 1160 in the proximal region of the first housing 1100, applying a force to the rigid strip 1620 in the -z direction causes a downward vertical movement of the first housing 1100 relative to the second housing 1200, which causes the rightmost elongated rigid member 1300 to move outward to the right in the +x direction, with the diagonal rail 1321 of the elongated rigid member 1300 moving outward along the diagonal groove 1130 in the first housing 1100 and the horizontal rail 1322 moving outward along the horizontal groove 1230 in the second housing 1200. A plurality of elongated rigid members 1300 follow, with the proximal region of the inner surface 1323 of the elongated rigid members 1300 creating a larger passage cross-sectional area 1361 than the distal inner surface 1311 of the elongated rigid members 1300, indicated by a gradual taper that reduces the cross-sectional area 1360 throughout the passage.

[0121] As the expansion assembly 1500 is further inserted to the point of its maximum possible cross-sectional area 1514, the rigid strips 1620 are forced to deform to their minimum outward position, thus creating an inner passageway 1623 equal to the outer cross-sectional area of ​​the expansion assembly 1500, at which point the horizontal rails 1322 and diagonal rails 1321 of the elongated rigid member 1300 are displaced, expanding the cross-sectional area of ​​the passageway created by the distal inner surface 1311 of the elongated rigid member 1300. This creates an open passageway 1350 through which the expansion assembly 1500 is inserted until the distal face of the constant diameter cannula head 1522 contacts the proximal face 1140 of the first housing 1100.

[0122] 8D-8E, in this embodiment, the obturator 1510 is separated from the constant diameter cannula 1520 to allow an instrument to be inserted through a hollow passage 1521 within the constant diameter cannula 1520. The obturator 1510 is removed by applying a normal force upward (proximally) to the distal face 1512 of the obturator head 1511 such that the constant diameter cannula 1520 remains in place within the expandable cannula by the elongated rigid member 1300.

[0123] 9A-9D, the previously described expandable cannula device 100 (of FIGS. 8A-8E) is shown operated in reverse, where the same mechanism for expanding the elongated rigid member 1300 with multiple rigid strips 1620 can be used to contract / compress the elongated rigid member 1300 back to its minimum cross-sectional area.

[0124] With particular reference to FIGS. 9A-9B, in this exemplary embodiment, the obturator 1510 is reinserted through a constant diameter cannula 1520 located within the expandable cannula device 100, which is surrounded by the rigid elongate member 1300.

[0125] With particular reference to FIG. 9C , the obturator 1510 and constant diameter cannula 1520 are simultaneously begun to be removed by applying an upward (proximal) force to the distal surface of the constant diameter cannula head 1522 while the rigid strip 1620 remains in place and applies a horizontal force to the expansion assembly 1500.

[0126] As the distal tip 1513 of the obturator 1510 moves upward (proximally) in the +z direction through the passageway 1623 created by the plurality of rigid strips 1620 and no longer contacts the distal inner surface 1311 of the elongate rigid member 1300, the rigid strips 1620 gradually contract inward to correspond to the decreasing taper of the distal obturator tip 1513 being removed. The force on the expansion assembly 1500 by the rigid strips 1620 causes the first housing 1100 to move vertically upward (proximally) in the +z direction to follow the direction of the expansion assembly 1500. The proximal region of the inner surface 1323 of the elongate rigid member 1300 maintains a larger passage cross-sectional area than the distal region of the contracted elongate rigid member 1300, indicated by the gradual taper of the decreasing cross-sectional area 1360 throughout the passageway.

[0127] With particular reference to FIG. 9D , when the expansion assembly 1500 is completely removed, the rigid strip 1620 contracts back to its original shape, the passage created by the inner surface of the rigid strip 1620 returns to its smallest passage 1623, and the elongated rigid member 1300 contracts back to its smallest cross-sectional area 1340.

[0128] In another embodiment, the same effect described above can be produced by removing the constant diameter cannula 1520 alone and without the obturator 1510 to collapse the expandable cannula device 100 .

[0129] 10A-10E, another exemplary embodiment of an expandable cannula device 100 (generally similar to the device of FIGS. 1A-1F) is shown, in which the obturator 1000 has a distal tip 1030 with a complementary geometry to the distal tip inner surface 1331 of the elongated rigid member 1300, for example, to create a substantially seamless internal and external interface with the elongated rigid member 1300 in the contracted state. Current obturators and cannulas do not have a seamless interface and therefore may result in higher insertion forces, and the cannula may tug and drag on the tissue into which it is inserted, causing further trauma. Sometimes, they may not completely penetrate either the tissue or the fascial layer. The seamless interface created in this embodiment can greatly reduce insertion forces and tissue damage and will be recognized as novel and non-obvious by those skilled in the art.

[0130] 10A , in this exemplary embodiment, the obturator 1000 includes a solid shaft 1020 having a cross-sectional area less than or equal to the inner cross-sectional area of ​​a passageway 1340 created by an elongated rigid member 1300 in a contracted state, extending distally to a tapered distal tip 1030, the proximal portion of which increases in cross-sectional area to a point where cross-section 1032 corresponds in area to the cross-section defined by the distal-most region 1330 of the elongated rigid member 1300 in its unexpanded (contracted) state 1340. The obturator tip 1030 continues to extend distally past cross-section 1032 but decreases in cross-sectional area until it has created the desired tip shape, which may be sharp, blunt, dolphin-nose, or may comprise a Veress needle or other alternative (as shown in FIGS. 13A-13C ).

[0131] In this embodiment, the distal tip inner surface 1331 of the elongate rigid member 1300 tapers outward at the distal end, with the angled taper parallel to the taper of the obturator tip 1031, such that the distal-most tip 1330 of the elongate rigid member 1300 creates a larger inner cross-sectional area than the region proximal to the taper.

[0132] In an alternative embodiment, the first housing 1100 may house a resistance member 1600 within the cavity 1160 .

[0133] 10B-10C, in this exemplary embodiment, the obturator 1000 is inserted concentrically through the first housing 1100 and guided toward the passageway 1340 created by the inner surface of the rigid elongate member 1300. When the larger cross-sectional area region 1032 of the obturator tip 1030 contacts the distal inner surface 1311 of the rigid elongate member 1300, the obturator tip 1030 exerts a force on the distal inner surface 1311 such that it momentarily creates a convex bend 1370 in the rigid elongate member 1300 at the point of contact. This cannot be achieved with conventional trocars that use a rigid, constant-diameter cannula, because the rigid cylinder prevents the passage of any object with a cross-sectional area larger than its inner diameter.

[0134] With particular reference to Figures 10D-10E, the obturator also includes a cylindrical head 1010 having an inner diameter greater than the outer diameter of the first housing 1100 but less than the outer diameter of the second housing 1200, and a height greater than the exposed height of the first housing 1100.

[0135] In another embodiment, the height of the cylindrical head 1010 can be at least equal to the exposed height of the first housing 1100, such that the distal surface 1011 of the obturator head 1010 contacts the proximal surface 1240 of the second housing 1200. It can also have cutouts 1013 throughout to improve grip for the hand and fingers.

[0136] When the obturator 1000 is fully inserted, the obturator tip taper 1031 lies flush with the inner surface 1331 of the rigid elongate member 1300 as their complementary tapers align, causing the rigid elongate member 1300 to contract around the obturator shaft 1020, losing its convex curvature 1370 and creating a tight, straight fit 1380 with the obturator 1000. The distal interface between the rigid elongate member 1300 and the obturator tip 1030 has a seamless internal and external interface, and the larger internal cross-sectional area created by the distal tip 1330 of the rigid elongate member 1300 is not only not parallel to the obturator tip 1032, but is also aligned with and contacts the maximum diameter of the obturator tip 1032, thereby providing a seamless interface for smooth insertion should the expandable cannula device 100 be inserted into tissue.

[0137] At the same time, the distal surface 1011 of the obturator head 1010 contacts the proximal surface 1240 of the second housing 1200, preventing the obturator 1000 from being inserted further, thereby creating a mechanical stop. In this embodiment, the mechanical stop interface still forms a seamless interface, but in other embodiments, the mechanical stop interface may not form a seamless interface. If the obturator 1000 were to be inserted further, because the obturator head 1010 does not extend all the way to the proximal surface 1240 of the second housing 1200, the obturator tip 1030 could protrude from the elongated rigid member 1300, losing the seamless interface, and the obturator head 1010 could apply a force to the first housing 1100, moving the first housing 1100 vertically downward (distal), potentially causing unwanted extension of the elongated rigid member 1300.

[0138] In an alternative embodiment, the complementary geometry (shape, size, and angle) 1031 of the distal tip 1030 and the distal inner surface 1331 of the elongate rigid member 1300 may be different, for example, having a cylindrical interface.

[0139] In alternative embodiments, the obturator head 1010 and distal face 1011 can include a user-controlled detachable mechanism for engaging and disengaging with the second housing 1200 and proximal face 1240. Examples of such mechanisms include a cantilever latch mechanism, or a twist lock mechanism, or other mechanisms known in the art.

[0140] 11A-11E, the expandable cannula device 100 described above (of FIGS. 10A-10E) is shown with the passageway created by the distal inner surface 1311 of the elongated rigid member 1300 expanded prior to entry of the obturator 1000.

[0141] With particular reference to FIG. 11A , as previously described, with respect to the coordinate system of FIG. 1C and with respect to the rightmost elongated rigid member 1300 shown in this cross-sectional view, a normal force in the −z direction is applied to the first housing 1100 relative to the second housing 1200, causing the rightmost elongated rigid member 1300 to move outward to the right in the +x direction, with the diagonal rail 1321 of the elongated rigid member 1300 moving along the diagonal groove 1130 in the first housing 1100 and the horizontal rail 1322 moving along the horizontal groove 1230 in the second housing 1200. The same outward movement occurs for the other elongated rigid members 1300, which move away from each other, thus increasing the cross-sectional area of ​​the passage created by the distal inner surfaces 1311 of the elongated rigid members 1300 and slightly expanding the passage 1390 of the expandable cannula device 100 to make room for the obturator 1000.

[0142] With particular reference to FIG. 11B, in this exemplary embodiment, the obturator 1000 is inserted through the first housing 1100 and guided toward a passage 1390 created by the inner surface of the elongated rigid member 1300, the inner cross-sectional area of ​​which is greater than the outer cross-sectional area of ​​the obturator tip 1030.

[0143] With particular reference to Figures 11C-11D, in this exemplary embodiment, when the obturator head 1010 contacts the proximal surface of the second housing 1200, the first housing 1100 remains downward (distal), causing the elongated rigid member 1300 to expand, so that the obturator tip 1030 is not flush with the inner surface taper of the distal tip 1331 of the elongated rigid member 1300.

[0144] To contract the elongated rigid member 1300 and create a flush interface between the obturator tip 1030 and the inner surface taper of the distal tip 1331 of the elongated rigid member 1300, an upward (proximal) force is applied to the first housing 1100 through the cut in the obturator head 1010, moving the first housing 1100 vertically upward (proximally) in the +z direction relative to the second housing 1200, again moving the elongated rigid member 1300 together and reducing the cross-sectional area of ​​the passageway created by the distal inner surface 1311 of the elongated rigid member 1300. The distal interface of the elongated rigid member 1300 and the obturator tip 1030 has a seamless inner and outer interface 1380, thereby allowing for smooth insertion should the expandable cannula device 100 be inserted into tissue.

[0145] With particular reference to FIG. 11E, in this exemplary embodiment, the obturator head 1010 has a notch in its side 1013 that allows the first housing 1100 to be pulled upward (proximally).

[0146] In an alternative embodiment, the obturator head 1010 may contact and be flush with the second housing 1200 in a different manner.

[0147] 12A-12D, the previously described expandable cannula device 100 (of FIGS. 10A-11E) is shown operated in reverse, where the obturator tip 1030, having a complementary geometry to the distal inner surface 1311 of the elongated rigid member 1300, is removed from the expandable cannula device 100, causing the elongated rigid member 1300 to contract back to its minimum cross-sectional area.

[0148] 12A-12C, in this exemplary embodiment, an upward (proximal) force is applied to the distal surface 1011 of the obturator head 1010 to begin removal of the obturator 1000. As the obturator 1000 is removed, the larger cross-sectional area 1032 of the obturator tip 1030 applies a force to the distal inner surface 1311 of the elongated rigid member 1300, increasing the inner cross-sectional area of ​​the passageway created by the distal inner surface 1311 of the elongated rigid member 1300 to a diameter equal to the outer cross-sectional area of ​​the obturator tip 1030. The force applied by the obturator tip 1030 to the distal inner surface 1311 of the elongated rigid member 1300 causes a convex bending.

[0149] With particular reference to FIG. 12D, when the obturator tip 1030 is no longer in contact with the inner distal surface 1311 of the rigid elongate member 1300, the rigid elongate member 1300 contracts back to its minimum cross-sectional area 1340.

[0150] In an alternative embodiment, the obturator 1000 is removed by first moving the first housing 1100 vertically downward (distal) relative to the second housing 1200, causing the elongated rigid members 1300 to move away from each other, before removing the obturator 1000.

[0151] 13A-13C, an exemplary embodiment of an obturator tip 1030 is shown in which the proximal surface of the obturator tip region 1031, which has a complementary geometry to the inner surface 1331 of the elongate rigid member 1300, remains the same, but the exposed tip has several possible geometries.

[0152] For example, with particular reference to FIG. 13A , an exemplary embodiment of the obturator tip 1030 described above is shown, in which the proximal surface of the obturator tip region 1031, having a complementary geometry to the inner surface 1331 of the elongate rigid member 1300, remains the same, but the exposed tip is in the shape of a sharp tip 1033.

[0153] With particular reference to FIG. 13B, the obturator tip 1030 previously described in FIG. 13A is shown, with the proximal surface of the obturator tip region 1031 having a complementary geometry to the inner surface 1331 of the elongate rigid member 1300 remaining the same, but the exposed tip being in the shape of a dolphin nose 1034 indicated by a concave edge and a blunt tip.

[0154] 13C , another exemplary embodiment of an obturator tip 1030 is shown in which the proximal surface of the distal tip region 1031, having a complementary geometry to the inner surface 1331 of the elongate rigid member 1300, remains the same, but the exposed tip 1037 includes a Veress needle 1035. The Veress needle tip is spring-loaded such that when the Veress needle tip contacts surface 1036, surface 1036 exerts an upward (proximal) force on the Veress needle tip 1035, causing it to retract upward (proximally) in the +z direction within the obturator shaft 1020, allowing the sharp face of the tip 1037 to pierce surface 1036. Veress needle tips are commonly used in laparoscopic procedures.

[0155] 14A-14E, another exemplary embodiment of the expandable cannula device 100 is shown that is generally similar to the previous embodiment, except that the distal regions 1330 of the elongated rigid members 1300 together form a seamless, closed tip 1332, which replicates the functionality of the obturator 1000, allowing the expandable cannula device 100 to be used without the obturator 1000, and can also be used with the navigation member 2500 or expanded to a larger diameter with the expansion assembly 1500.

[0156] With particular reference to Figures 14A-14B, in this exemplary embodiment, the distal regions 1330 of the elongate rigid members 1300 together form a seamless closed tip 1332 that allows the expandable cannula device 100 to be used without the obturator 1000 as the closed tip 1332 replicates the functionality of the obturator 1000.

[0157] In alternative embodiments, the closed tip 1332 may have various angles and shapes and may be sharp or blunt.

[0158] 14C-14D , in this exemplary embodiment, a navigation member 2500, such as an optical or electromagnetic navigation probe, can be inserted through the lumen 1340 of the elongate rigid member 1300 and rest on the flat inner surface 1333 of the closed tip 1332 of the expandable cannula device 100 to provide positional data about the closed tip 1332 when inserted into tissue. This embodiment is useful for neurosurgical applications where navigation probes are often used to identify tip location within the brain. The navigational probe 2500 can also be proximally locked relative to the first housing 1100, the second housing 1200, or both, by a set screw mechanism or resistance member 1600 located within the first housing, as previously described.

[0159] With particular reference to FIG. 14E, in this exemplary embodiment, the expandable cannula device 100 can be inserted into tissue and the expansion assembly 1500 can be inserted to expand the elongated rigid member 1300 as in the previously described embodiment, with the distal surface 1525 of the constant diameter cannula 1520 being flat and resting on the flat inner surface 1333 of the closed tip 1332 of the elongated rigid member 1300.

[0160] In alternative embodiments, the distal surface 1525 of the constant diameter cannula 1520 can connect to the inner surface 1333 of the closed tip 1332 of the rigid elongate member 1300 in a variety of different complimentary ways and shapes.

[0161] 15A-15D , another exemplary embodiment of an expandable cannula device 100 is shown in an unexpanded state 1340 and an expanded state 1350 that is generally similar to the previous embodiment, except that the cannula device includes a first sealing resilient member 1710 and a second sealing resilient member 1720 that covers the exterior surface of the expandable cannula device 100, with the second sealing resilient member 1720 assembled differently. A one-way valve 1190 and resistance member in the form of a backup valve 1610 is located within a cavity 1160 in the proximal region of the first housing 1100 and provides a fluid seal that prevents fluid communication between the cannula lumen and the external environment, even when an instrument is placed within the cannula.

[0162] 15A, in this exemplary embodiment, the first sealing resilient member 1710 is a resilient member that covers the outer surface 1312 of the elongated rigid member 1300 from the distal tip 1330 upward (proximally) to the outer surface 1270 of the second housing 1200. The first sealing resilient member 1710 may be an elastomer having a low Shore hardness and high elongation and tensile strength, such as silicone, polyisoprene, or neoprene, and may be manufactured by dip molding, coating, or casting methods, and potentially multi-cycle dip coating.

[0163] The proximal portion 1713 of the first sealing resilient member 1710 may be maintained in place on the second housing 1200 using an adhesive. The distal portion 1714 of the first sealing resilient member 1710 may be maintained in place on the distal tip 1330 of the elongate rigid member 1300 using an adhesive.

[0164] In an alternative embodiment, the first sealing resilient member 1710 may be stretched to an unexpanded state 1340 of the elongated rigid member 1300 in which the resilience is sufficient to maintain the first sealing resilient member 1710 in firm contact with the outer surface of the elongated rigid member 1300 without the use of permanent adhesives.

[0165] The first sealing elastic member 1710 can be assembled onto the expandable cannula device 100 by being rolled up from the distal end 1330 of the elongated rigid member 1300 and held permanently or non-permanently by the second housing 1200.

[0166] In an alternative embodiment, the first seal member 1710 may have surface modifications such as thicker areas or ribs to provide better retention within tissue.

[0167] In this embodiment, the second sealing elastic member 1720 is an elastic member that covers the area between the proximal surface 1140 of the first housing 1100 where the through hole 1110 begins and the second housing 1200 .

[0168] The second sealing resilient member 1720 may be an elastomer made from the same material as the first sealing resilient member 1710 as previously described.

[0169] The proximal portion 1723 of the second sealing elastic member 1720 can be maintained in place on the first housing 1100 by compressing or pinching it under a cap 1180 that is attached to the first housing 1100 by a press fit or screw mechanism, which simultaneously compresses the resistance member 1610 to create a tight seal and prevent gas loss.

[0170] The combination of the first sealing resilient member 1710 and the second sealing resilient member 1720, when it completely seals the expandable cannula device 100 from the tip 1330 of the elongated rigid member 1300 to the proximal face 1140 of the first housing 1100, prevents fluid leakage between the concentric interfaces of the first housing 1100 and the second housing 1200 and around the elongated rigid member 1300 between the elongated rigid member 1300 and the second housing 1200. However, the first sealing resilient member 1710 and the second sealing resilient member 1200 do not prevent leakage through the cannula through-hole when this is done using a valve system ( FIG. 32 ) described below.

[0171] 15B , in this exemplary embodiment, as expandable cannula device 100 expands, first seal resilient member 1710 stretches 1712 to accommodate the increasing cross-sectional area of ​​outer surface 1312 of elongate rigid member 1300, while second seal resilient member 1720 contracts 1722 to accommodate first housing 1100 moving vertically downward (distally) relative to second housing 1200. Both first seal resilient member 1710 and second seal resilient member 1720 remain intact during expansion and contraction to maintain a fluid seal and prevent fluid from transmitting between the cannula lumen and the external environment.

[0172] In an alternative embodiment, seal members 1710 and 1720 may be constructed of two or more layers of material and / or may include a mesh structure.

[0173] In an alternative embodiment, seal members 1710 and 1720 may be detachable from expandable cannula device 100 .

[0174] In an alternative embodiment, the seal members 1710 and 1720 may be heat shrinkable.

[0175] In an alternative embodiment, the first seal resilient member 1710 can help contract the expandable cannula device 100 in the absence of the expansion assembly 1500. When the first seal resilient member 1710 is in its expanded state 1712, it is under tension, which exerts a radially inward force on the outer surfaces 1312 of the elongate rigid members 1300, causing them to contract to the unexpanded state 1340, thereby returning the first seal resilient member 1710 to its initial state with minimal or no tension 1711.

[0176] In an alternative embodiment, as in FIGS. 5A-5E , contraction of the expandable cannula device 100 may be initiated by removal of the expansion assembly 1500 using the resistance member 1610, with superior (proximal) removal of the obturator tip 1513. 1) the distal region 1310 of the rigid elongate member 1300 contracts as a result of the first seal resilient member 1710 exerting a radially inward force on the outer surface 1312 of the rigid elongate member 1300, as described above; 2) The resistance member 1600 begins to move the first housing 1100 upward (proximally) in accordance with the obturator tip 1523, causing the proximal region 1320 of the elongated rigid member 1300 to contract back to its minimum cross-sectional area 1340.

[0177] 15C-15D , an alternative exemplary embodiment is shown in which the proximal portion 1723 of the second sealing resilient member 1720 may be maintained in place on the first housing 1100 by placing an O-ring 1750 or similar resilient component over the second sealing resilient member 1720 in a groove created between the first housing 1100 and the cap 1180, and then covering the proximal portion 1723 over the O-ring 1750. This creates a tight seal and prevents gas loss from the moving parts enclosed within the second sealing resilient member 1720.

[0178] The distal portion 1724 of the second sealing resilient member 1720 may be maintained in place on the second housing 1200 using adhesive or an O-ring 1750 arrangement, as described above.

[0179] 16A-16B, an alternative embodiment of the first and second sealing resilient members 1710, 1720 previously described (of FIGS. 15A-15D) is shown, where the first sealing resilient member 1710 remains the same and the second sealing member is flexible but non-stretchable, and may be accordion-shaped or serrated 1730 such that when the cannula 100 is expanded, the surfaces of the accordion-shaped 1735 come closer together, increasing the outer cross-sectional area of ​​the second sealing member 1730.

[0180] In some embodiments, the second seal member 1730 can resemble bellows, serrated, corrugated, zigzag folded, and other accordion-style shapes.

[0181] In some embodiments, the second seal member 1730 can be made of a woven or polymeric material that is relatively difficult to stretch, for example, with an elastic modulus in the range of 12-2000 MPa.

[0182] 17A-17B, another exemplary embodiment of an expandable cannula device is shown that is generally similar to the previous embodiment, except that a single sealing resilient member 1740 is provided, and functionality remains the same, remaining intact during expansion and contraction to maintain a fluid seal and prevent fluid transmission between the cannula lumen and the external environment.

[0183] The single sealing resilient member 1740 can be constructed from a variety of different elastomeric materials with high elongation and tensile strength, such as dip-molded silicone, polyisoprene, or neoprene, and can be hydrophobic or hydrophilic.

[0184] As previously described, the single sealing elastic member 1740 can be assembled by pulling the entire member over the expandable cannula device 100 from the distal tip 1330 of the elongated rigid member 1300 upward (proximally) to the proximal face 1140 of the first housing 1100, where it can be maintained in place by compressing it under the valve cap 1180, by using adhesive, or by holding it in place by an O-ring 1750 mechanism.

[0185] 18A-18B, another exemplary embodiment of an expandable cannula device is shown that is generally similar to the previous embodiment. As with the previous embodiment, the first seal resilient member 1710 or the single seal resilient member 1740 are both referred to interchangeably in this embodiment and set of figures. This is because the first seal resilient member 1710 further describes the distal section and surrounds the outer surface 1312 of the elongated rigid member 1300. Thus, the seal member 1710 is exposed to external forces, such as friction, from tissue during insertion, which can cause the first seal member 1710 to catch on the surface and tear or roll up the elongated rigid member 1300. In this alternative embodiment, the previously described elongated rigid members 1300 are described that protect the first seal member 1710 using a U-shaped geometry 1400.

[0186] With particular reference to Figures 18A-18B, in this exemplary embodiment, the elongated rigid member is u-shaped 1400 and the groove 1411 is located along the outer surface 1412 of the straight portion of the elongated rigid member 1400 and resembles a u-channel or slot 1411 into which the first seal member 1710 can be inserted.

[0187] In this embodiment, the first seal member 1710 is disposed within a u-channel 1411. The outer surface 1412 of the u-shaped elongated rigid member 1400 protects the first seal member 1710 by preventing external forces from acting directly on it and potentially curling or tearing the distal end 1714 during initial entry into tissue.

[0188] The U-shaped elongated rigid member 1400 can also help prevent gas loss from the distal end of the expandable cannula device as it eliminates any possible gaps between the distal end of the U-shaped elongated rigid member 1400 and the distal end 1714 of the first seal member 1710.

[0189] The first seal member 1710 may be adhered to the u-shaped elongated rigid member 1400 on either surface within the u-channel 1411 .

[0190] In the following embodiments, as shown in Figures 26-28, the U-shaped elongated rigid member 1400 not only protects the first seal member 1710, but also allows optional surface modifications to the outer surface 1412 of the elongated rigid member 1400 to enhance fixation, guide the incision, or allow for the accommodation of a blade to create the incision.

[0191] In an alternative embodiment, as shown in FIG. 20, the u-channel 1411 may not be as deep and may resemble a small groove in the proximal end of the current u-shaped elongated rigid member 1400 .

[0192] 19A-19B, an alternative exemplary embodiment of the previously described u-shaped elongated rigid member 1400 (FIG. 18) is shown. In this embodiment, the outer surface 1412 of the u-shaped elongated rigid member 1400 has a surface modification 1413 thereon to enhance anchoring of the expandable cannula device 100 in tissue, such that the surface modification 1413 increases contact and friction with the tissue, reducing the likelihood of the cannula slipping out of the tissue.

[0193] In alternative embodiments, the surface modification 1413 may be in the form of ridges, peaks, any extrusion, or extrusion kerfs.

[0194] 20A-20B, an alternative exemplary embodiment of the previously described u-shaped elongated rigid member 1400 (FIGS. 18-19) is shown. In this example, the outer surface 1412 of the u-shaped elongated rigid member 1400 has a surface modification 1413, and the u-channel is in the form of a small groove 1420 in a distal-most surface modification 1430 of the u-shaped elongated rigid member 1400, which may be wider than the proximal surface modification.

[0195] The first seal member 1710 is inserted into the groove 1420 in the distal-most surface modification 1430 and can wrap tightly around the additional surface modification. The distal-most surface modification 1430 prevents the seal member from rolling up due to friction when the expandable cannula device 100 is inserted into tissue.

[0196] First seal member 1710 may or may not be bonded within a groove in distal-most surface modification 1430 .

[0197] 21A-21B, there is shown an alternative exemplary embodiment of the previously described rigid elongate member 1400. In this embodiment, the outer surface of the rigid elongate member 1400 has a surface modification 1413, with the distal-most surface modification having a larger diameter, thickness, or cross-sectional area than the proximal surface modification feature.

[0198] The first seal member 1710 can be wrapped tightly around the proximal surface modification and positioned proximal to the distal-most surface modification 1430 so that the first seal member 1710 creates a leading edge and front surface in the tissue, which can prevent the first seal member 1710 from directly contacting the tissue and preventing it from rolling up due to friction from inserting the expandable cannula device 100 into the tissue.

[0199] The first seal member 1710 may be adhered behind the distal-most surface modification 1430 .

[0200] 22A-22D and 23A-23D, an alternative exemplary embodiment of the previously described u-shaped elongated rigid member 1400 (FIGS. 18-19) is shown. In this embodiment, the u-shaped elongated rigid member 1400 can be separated into an inner part 1451 and an outer part 1452, and the outer part 1452 can be attached to the inner part 1451 to form a u-channel 1411 into which the first seal member 1710 is inserted.

[0201] With particular reference to Figures 22A-22D, in this exemplary embodiment, the outer component is a tongue 1452 and the inner component is a groove 1451 in the distal tip 1440, and the outer component 1452 can slide into the inner component 1451 and lock into place.

[0202] In alternative embodiments, the external component 1452 may be locked in place by a press fit or adhesive / epoxy and / or may have a surface modification 1413 .

[0203] In an alternative embodiment, the fit may be in the form of a lock and key, or may be detachable.

[0204] 23A-23D, in this alternative exemplary embodiment, the outer component is a groove 1453 in the distal tip 1440 and the inner component 1454 is a tongue. The inner component 1454 can slide into the groove in the outer component 1453 and lock into place.

[0205] In alternative embodiments, the external component 1453 may be locked in place by a press fit or adhesive / epoxy and / or may have a surface modification 1413 .

[0206] The first seal member 1710 can be inserted into the u-channel 1411 and locked into place either before or after the inner and outer components are assembled.

[0207] 24A-24D, in this alternative exemplary embodiment, the outer part has an extruded surface modification 1461 that presses into a cut surface modification in the inner part 1462, which can penetrate the first seal member 1710 to compress or lock it in place.

[0208] 25A-25B, in this alternative exemplary embodiment, outer component 1471 comprises distal tip 1440 and two grooves 1472 within the inner surface of region 1473 where the distal tip ends and the u-channel begins, and inner component 1474 comprises the entire elongated rigid member 1400, with the distal region having two rails along either side 1475. Rails 1475 and grooves 1472 allow outer component 1471 to slide distally over inner component 1474 and be glued in place to form the u-channel. In alternative embodiments, the geometry of the rail configuration may be different.

[0209] 26A-26D, in this alternative exemplary embodiment, the outer surface 1412 of the proximal region of the u-shaped elongated rigid member 1400 includes a vertical groove / guide 1480 for making an incision with a blade to create an incision of a predetermined size and shape when the expandable cannula device 100 must be expanded to a larger size.

[0210] 27A-27D, in this alternative exemplary embodiment, a u-shaped elongated rigid member 1400 comprises a cannula having at least one blade 1490 located on an outer surface 1412 of a proximal region of the u-shaped elongated rigid member 1400. In situations where the expandable cannula device 100 must be expanded to a larger size, the incision in the skin is widened using a scalpel, but in this embodiment, the blade 1490 is incorporated into the u-shaped elongated rigid member 1400 so that the incision can be widened to provide a streamlined expansion without surgeon's intervention.

[0211] When the elongate rigid member 1400 expands, the blades 1490 contact the tissue and immediately apply a force that cuts the tissue. When the device is expanded, the blades 1490 no longer apply a force to the tissue and therefore do not cut further.

[0212] In an alternative embodiment, the user can angle the expandable cannula device 100 towards the blade 1490 to apply force to the tissue, thereby cutting.

[0213] 28A-28E, in this alternative exemplary embodiment, the blade 1490 may have a cover 1491 to prevent unwanted actuation of the blade 1490. The blade cover 1491 may be in the form of a sliding door or a removable cover.

[0214] 29A-29D, an exemplary embodiment of the expandable cannula device 100 is shown, in which the expansion of the elongated rigid member 2000 is actuated by a hinge system 2100 connecting the first housing 1800 to the elongated rigid member 2000.

[0215] With particular reference to FIGS. 29A-29B, expandable cannula device 100 includes a cylindrical first housing 1800 defining a first throughbore 1810, a plurality of elongated rigid members 2000 cooperatively defining passages axially aligned with first throughbore 1810, a hinge system 2100 connecting elongated rigid members 2000 to first housing 1800, and a second housing 1900 defining a second throughbore 1910, wherein second housing 1900 is hinged to first housing 1800. 18. An exemplary embodiment of an expandable cannula device 100 is shown in which a second housing 1900 is concentric with a first housing 1800 and is vertically movable relative to the first housing 1800, and a second housing 1900 is operably connected to the elongated rigid members 2000 such that vertical movement of the first housing 1800 relative to the second housing 1900 causes a hinge system 2100 to move the elongated rigid members 2000 away from each other, increasing the cross-sectional area of ​​the passageway 2040.

[0216] In this embodiment, the plurality of rigid elongate members 2000 comprises an inner surface 2010 and an outer surface 2011, a proximal horizontal rail 2030 perpendicular to the long axis of the rigid elongate members 2000 that is complimentary to the horizontal groove 1920 in the second housing 1900, and a pin 2130 on the outermost edge of the horizontal rail 2030 perpendicular to the horizontal groove 1920 in the second housing 1900. The inner surface 2010 of the plurality of rigid elongate members 2000 defines the cross-sectional area of ​​the passageway.

[0217] In this embodiment, the first housing 1800 has a plurality of vertical grooves / kerfs 1820, each having a pin 2120 fixed on either side of the groove near the edge of the through hole 1810 perpendicular to the kerf 1820 that connects to the elongated rigid link 2110.

[0218] In an alternative embodiment, the first housing may resemble a hollow cylinder or ring.

[0219] In this embodiment, the second housing 1900 has a plurality of horizontal grooves or cutouts 1920, each horizontal groove 1920 complementary to a horizontal rail 2030 of the elongated rigid member 2000 and cut out on the proximal surface of the second housing 1900 to allow the elongated rigid link 2110 to move freely.

[0220] In this embodiment, the hinge system 2100 includes a plurality of elongated rigid links 2110 with symmetrical holes on their distal and proximal ends 2111, 2112, a proximal pin 2120 in the first housing 1800, and a parallel distal pin 2130 in the elongated rigid member 2000, with the holes in the elongated rigid links 2110 being complementary in diameter to the pins. The elongated rigid links 2110 are connected to each of these pins to allow rotational movement to occur about the long axis of the pin. The plurality of proximal pins 2120 in the first housing 1800 are closer to the z-axis of the center of the through-hole 1810 of the first housing 1800 than the distal pin 2130 in the elongated rigid member 2000, creating an initial acute angle when the elongated rigid member is unexpanded 2040.

[0221] In an alternative embodiment, this initial angle may be increased or decreased to vary the rate of axial movement of the first housing 1800 within the second housing 1900, and therefore the rate of expansion of the multiple elongated rigid members 2000.

[0222] In an alternative embodiment, the number of elongated rigid links 2110, proximal pins 2120, and distal pins 2130 may be increased.

[0223] 29C-29D, as previously described, with respect to the illustrated coordinate system, which is the same as in FIG. 1C and in which the second housing 1900 is fixed at the origin, when a normal force in the -z direction is applied to the first housing 1800, the proximal portion 2112 of the right elongated rigid link 2110 moves downward (distally) in the -z direction while rotating on the proximal pin 2120 in the first housing 1800. Because the elongated rigid link 2110 is rigid, its length must remain the same, and because it is pinned at both ends, it must move while maintaining its stiffness. Thus, when the proximal portion 2112 of the right elongated rigid link 2110 is forced downward (distally) in the −z direction, this causes the distal portion 2111 of the right elongated rigid link 2110 to move downward (distally), but because it is attached to the distal pin 2130 in the horizontal rail 2030 of the right elongated rigid member 2000, the right elongated rigid link 2110 causes the horizontal rail 2030 of the right elongated rigid member 2000 to move outward in the +x direction within the horizontal groove 1920 in the second housing 1900. The same outward movement occurs for the other elongated rigid members 2000, moving them away from each other, thus increasing the cross-sectional area of ​​the passageway created by the inner surfaces 2010 of the elongated rigid members 2000 and expanding the passageway 2050 of the expandable cannula device 100.

[0224] The second housing 1900 remains fixed at the origin, while the first housing 1800 is displaced in the -z direction relative to the second housing 1900, the elongated rigid link 2110 has an angle that is smaller than the starting position (in an alternative embodiment, the angle may be zero), and the multiple elongated rigid members 2000 are displaced radially outward relative to the second housing 1900.

[0225] In an alternative embodiment, the hinge system 2100 can resemble a slider-crank mechanism.

[0226] In an alternative embodiment, the same mechanism of expansion can be used to contract the elongate rigid member 2000 by reversing the movement of the first housing 1800 relative to the second housing 1900, i.e., moving it in the +z direction relative to the second housing.

[0227] 30A-30D, another exemplary embodiment of the expandable cannula device 100 is shown, which may be substantially similar to any of the previous embodiments, although showing a single sealing resilient member 1740. In this embodiment, the cannula device may be attached to the robotic surgical system 2200 using a mount 2300 secured to the outer surface 1270 of the second housing 1200 and to the robotic arm 2200.

[0228] With particular reference to Figures 30A-30B, in this exemplary embodiment, the mount 2300 comprises a circular body 2310 having an inner cross-sectional area complimentary to the outer cross-sectional area of ​​the second housing 1200, and an extruded adapter 2320 that may be operably connected to the robot arm 2200 by any detachable mechanical fastening mechanism known in the art.

[0229] In alternative embodiments, the circular body 2310 of the mount 2300 may have a different geometric shape, and the inner geometric shape may be complimentary to and operably connected to the outer surface 1270 of the second housing 1200.

[0230] 30C-30D, the mount 2300 can be attached to the expandable cannula device 100 using any form of mechanical fastening, including pins, a press or friction fit, screws, a series of grooves / rails, a latching mechanism, etc. The mount 2300 can be made from a variety of different rigid materials, including injection molded plastic or metal.

[0231] 31A-31F, another example of an expandable cannula device that can be attached to a robotic arm is shown. In this exemplary embodiment, a compressible mount 2400 is provided that may or may not be connected to the robotic arm 2200 and can initiate expansion of the expandable cannula device 100 using a mechanical mechanism.

[0232] With particular reference to Figures 31A-31B, the mount 2400 comprises a proximal part 2410 and a distal part 2420 connected by a mechanical mechanism 2430, such as a linear actuator, that can be actuated to move the proximal part 2410 and the distal part 2420 closer together or further apart.

[0233] The mount mechanism 2430 can be pneumatic, hydraulic, spring-loaded, electric, electromechanically powered, or any other actuation system. The mount 2400 can be actuated to initiate expansion by pressing a button on the mount itself, or independently using a remote, wired, or wireless controller.

[0234] The mount 2400 is attached to the expandable cannula device 100 in contact with the proximal surface 1140 of the first housing 1100 and the distal surface 1250 of the second housing 1200, such that actuation of the mechanical mechanism 2430 causes the proximal component 2410 to apply a force to the proximal surface 1140 of the first housing 1100 and the distal component 2420 to apply a force to the distal surface 1250 of the second housing 1200, causing compression that initiates expansion of the expandable cannula device 100. The compression can be controlled such that either the proximal component 2410 or the distal component 2420 can be stationary while the other component moves toward the other, causing actuation that can be useful in situations where the depth of the expandable cannula device 100 in tissue must not change during expansion.

[0235] In this embodiment, the proximal region of the inner surface 1323 of the elongate rigid member 1300 creates a larger passage cross-sectional area 1361 than the distal inner surface 1311 of the elongate rigid member 1300, indicated by a gradual taper that reduces the cross-sectional area 1360 throughout the passage.

[0236] 31C-31D , in this exemplary embodiment, the expansion assembly 1500 is inserted downward (distally) through the passageway 1340 created by the through-hole 1110 of the first housing 1100 and the distal inner surface 1311 of the elongated rigid member 1300. The distal tip 1513 of the obturator 1510 within the expansion assembly 1500 initiates contact with the distal inner surface 1311 of the elongated rigid member 1300 at the smaller passage cross-sectional area 1362, causing the distal region 1310 of the elongated rigid member 1300 to expand such that the distal inner surface 1311 of the elongated rigid member 1300 surrounds the expansion assembly 1500.

[0237] 31E-31F, in this exemplary embodiment, the obturator 1510 is removed from the constant diameter cannula 1520 to allow an instrument to be inserted through the hollow passage 1521 within the constant diameter cannula 1520. The obturator 1510 is removed by applying a normal force upward (proximally) to the distal face 1512 of the obturator head 1511 such that the constant diameter cannula 1520 remains in place within the expandable cannula by the elongated rigid member 1300.

[0238] In an alternative embodiment not shown, the robotic arm 2200 can guide the expansion assembly 1500 downward (distally) and concentrically into the expandable cannula device 100, utilizing the expansion initiated by the resistance member 1600 described above and in connection with Figures 4A-9D to expand the cannula device 100 to a larger diameter.

[0239] 32A-32D , another exemplary embodiment of an expandable cannula device 100 is shown, which may be generally similar to any of the previous embodiments, except that the cannula device includes a side port with a stopcock 1280. As shown, the cannula device also includes a single sealing resilient member 1740, as well as a one-way valve 1190 and a backup valve 1610 that can prevent gas leakage with and without an instrument. The cannula device can be used in cooperation with a constant diameter cannula 1520 that includes one or more holes, e.g., an array of holes 1524, disposed around the periphery of the proximal region of the cannula 1520. The constant diameter cannula 1520 can also include a valve system 1540 having a backup valve 1541 and a one-way valve 1542 that can also prevent gas leakage with and without an instrument. The expandable cannula device 100 and constant diameter cannula 1520 are shown together, with the combination of the valve system and single sealing resilient member 1740 working together to prevent gas leakage from the entire device 100.

[0240] 32A-32B, this exemplary embodiment shows an expandable cannula device 100 having a stopcock 1280 configured to vent or release gas through the lumen of the cannula. The stopcock 1280 is connected to the expandable cannula device 100 through a hole 1290 in the second housing 1200, which results in an extrusion slit 1170 in the first housing 1100 that allows gas to travel into the passageway created by the through-holes 1110 in the first housing 1100 and the rigid elongate member 1300. The stopcock 1280 may comprise a lever that controls the flow rate of gas in and out.

[0241] In this embodiment, expandable cannula device 100 is covered by a single sealing resilient member 1740, and first housing 1100 houses a one-way valve 1190 in the form of a flat backup valve (referred to interchangeably in this regard) and resistance member 1610 that are compressed by resistance member cap 1180. All of these components interact together in preventing gas loss from expandable cannula device 100 when there is no instrument inserted therethrough, and even when there is an instrument inserted therethrough. Single sealing resilient member 1740 seals gaps surrounding elongated rigid member 1300 and gaps between first housing 1100 and second housing 1200, as well as gaps between elongated rigid member 1300 and second housing 1200, all of which have been described in detail in the previous sections of this description, and particularly in the sections associated with FIGS. 15A-17B.

[0242] In this exemplary embodiment, one-way valve 1190 is a cross-slit valve made from silicone or similar material in this embodiment which in the rest position prevents gas from flowing all the way up to valve 1190, however, when an instrument is present, one-way valve 1190 will open, thus the need for backup valve 1610. In other embodiments, one-way valve 1190 can be in the form of a duckbill valve or other one-way valve known in the art.

[0243] 4-7, the backup valve 1610 is made from a resilient member having a concentric hole 1611 that can stretch to fit the expansion assembly 1500 or instrument 2511 therein and contract to return to its original hole cross-sectional area after the expansion assembly 1500 or instrument is removed, the concentric hole 1611 having a cross-sectional area that is smaller than the cross-sectional area of ​​the member inserted therethrough. The backup valve 1610 can be made from a thin polymer such as polyisoprene or silicone, which can be made from a sheet polymer from which the hole 1611 can be punched.

[0244] Thus, in the rest position, one-way valve 1190 prevents gas from escaping through through-hole 1110, and when an instrument 2511 is present, one-way valve 1190 opens and no longer prevents gas from escaping. Backup valve 1610 then stretches around the instrument without a gap to create an airtight seal. This system is important to maintain gas ventilated to the patient because one-way valve 1190 and backup valve 1610 do not work independently, so that one-way valve 1190 leaks when an instrument is inserted through it, and backup valve 1610 leaks in the rest position when no instrument 2511 is inserted because it has a hole 1611 that does not close.

[0245] In an alternative embodiment, the backup valve 1610 seals around the obturator 1000 to prevent gas loss during initial entry in the tissue.

[0246] In alternative embodiments of the backup valve 1610, it may be flat, floating, jagged, wavy, laminar, or have any combination thereof as known and described in the prior art.

[0247] 32C , one exemplary embodiment of a constant diameter cannula 1520 is shown having a head 1535 with an array of holes 1524 surrounding the area of ​​a hollow cylindrical passageway 1521 that allows gas to enter and leave the constant diameter cannula 1520, and a valve system 1540 having a backup valve 1541 and a one-way valve 1542. In this embodiment, the backup valve 1541 is a conical backup valve 1541, but in other embodiments, the backup valve 1541 may be flat, floating, jagged, wavy, laminar, or any combination thereof known and described in the prior art. In this embodiment, the one-way valve 1542 is shown as a cross-slit valve (referred to interchangeably herein), but in other embodiments, the one-way valve 1542 may be a duckbill valve or other known one-way valve known in the art.

[0248] The one-way valve 1542 in the head 1535 is similar to the cross-slit valve 1190 in the expandable cannula device 100 in terms of material properties, cross-slit shape, and function, but is slightly smaller because it only needs to fit instruments smaller than the diameter of a given cannula device hollow passage 1521, whereas the one-way valve 1190 in the expandable cannula device 100 must fit the entire expansion assembly 1500, which has a larger diameter. It functions the same in that in the rest position it prevents gas from flowing through the valve 1542, but when an instrument or obturator 1510 is present, the one-way valve 1542 is opened, hence the need for the conical backup valve 1541.

[0249] The conical backup valve 1541 has a central bore 1546 with an inner diameter that can be stretched to accommodate a range of obturator 1510 and instrument sizes and then contracts back to its original inner diameter using its elastic properties. The conical backup valve 1541 may be an elastomer with low Shore hardness and high elongation and tensile strength, such as silicone or polyisoprene, and can be manufactured by injection or compression molding. Just as the flat backup valve 1610 prevents gas leakage from the through-hole 1110 of the expandable cannula device 100 when an instrument is present, the conical backup valve 1541 prevents gas leakage from the through-hole 1521 of the constant diameter cannula 1520. However, whereas the flat backup valve 1610 can only prevent gas leakage when the instrument is perfectly concentric, the conical valve 1541 also has the ability to pivot with the instrument to always prevent gas leakage (as further described in FIG. 34 ).

[0250] In alternative embodiments, the conical backup valve 1541 and the one-way valve 1542 may have different geometries.

[0251] In an alternative embodiment, as shown in FIG. 33, the valve system 1540 is removable for quick degassing or specimen withdrawal.

[0252] 32D, in this exemplary embodiment, constant diameter cannula 1520 within expandable cannula device 100 is shown expanded to a larger diameter, allowing gas to be transmitted through stopcock 1280 and through holes 1524 in constant diameter cannula 1520, allowing gas to flow through cylindrical passageway 1521 of constant diameter cannula 1520 into the enclosed area undergoing surgery, and vice versa. Elongated rigid member 1300 is not visible in this particular cross section due to its different orientation relative to stopcock 1280.

[0253] The holes 1524 are configured so that gas can enter / leave through at least one of the holes 1524 independent of the direction in which the constant diameter cannula 1520 is inserted into the expandable cannula device 100. In alternative embodiments, the holes 1524 may be distributed in different arrangements to affect the flow of gas.

[0254] In this embodiment, the single sealing resilient member 1740, the backup valve 1610, the one-way valve 1190 in the first housing 1100, the conical backup valve 1541, and the one-way valve 1542 in the constant diameter cannula 1520 all work collectively to prevent gas leakage. The single sealing resilient member 1740 completely seals the expandable cannula device 100 from the tip 1330 of the elongated rigid member 1300 to the proximal face 1140 of the first housing 1100, preventing gas leakage between the concentric interfaces of the first housing 1100 and the second housing 1200, and between the elongated rigid member 1300 and the second housing 1200, around the elongated rigid member 1300 in both the contracted and expanded states (as shown in FIGS. 15-17 ).

[0255] When the constant diameter cannula 1520 is inserted into the expandable cannula device 100, the constant diameter cannula 1520 impairs the ability of the one-way valve 1190 to seal out the gas. However, at the same time, it stretches the backup valve 1610 within the first housing 1100 until it is fully inserted, where the bore 1524 of the constant diameter cannula 1520 is located distal to the stretched resistance member 1610 (backup valve), as described in the previous embodiment. The backup valve 1610 thereby ensures that the gas seal is maintained for the entire assembly. This allows expansion to occur with minimal gas loss, which is important during surgery because it prevents collapse of the ventilated working space during emergency expansion.

[0256] Conical backup valve 1541 and one-way valve 1542 in constant diameter cannula 1520 then prevent gas leakage from through-hole 1521 with and without an instrument (further explained in FIG. 34), as described above.

[0257] 33A-33E, another exemplary embodiment of the expandable cannula device 100 is shown that is generally similar to the previous embodiment, but is shown surrounded by a single sealing resilient member 1740 having a constant diameter cannula 1520 therein, wherein the head 1535 housing the conical backup valve 1541 and one-way valve 1542 can be separated from the distal cylindrical body 1521 by a latching mechanism 1536 to provide a full diameter open passageway 1521 for rapid degassing of gas, which can be important during an emergency situation when the CO2 pressure is too high and could, for example, cause an embolism, or for specimen retrieval 2522.

[0258] With particular reference to Figures 33A-33D, in this exemplary embodiment, the head 1535 is released by twisting the latch mechanism 1536 counterclockwise to position it back and guide it upward (proximally) and out of the cylindrical body 1521, or vice versa.

[0259] In alternative embodiments, the latch mechanism 1536 can be any type of unlocking mechanism, such as a snap lock and push release.

[0260] In an alternative embodiment, the latch 1536 can house only the backup valve 1541 , with the one-way valve 1542 remaining within the cylindrical passage 1521 .

[0261] 33E , in this embodiment, if a user intends to remove a specimen 2522 that is larger than the inner diameter of the conical backup valve bore 1546, the head 1535 should be removed so that the specimen 2522 can be guided down to the cylindrical passage 1521 without interfering with the valve system 1540. A user can insert an instrument 2511, such as a grasping forceps, through the lumen 1520 of the constant diameter cannula to grasp the specimen 2522 and pull it proximally through the cylindrical passage 1521, and the head 1535 can be separated and pulled proximally along with the instrument 2511 and specimen 2522.

[0262] 34A-34D, another exemplary embodiment of the expandable cannula device 100 is shown that is generally similar to the previous embodiment surrounded by a single sealing resilient member 1740 having a constant diameter cannula 1520 therein, with a head 1535 containing a conical backup valve 1541, a serrated shield 1543, and a one-way valve 1542 compressed by a valve cap 1537, allowing various instruments to be inserted through the cylindrical passageway 1521 of the constant diameter cannula 1520 while maintaining an airtight seal.

[0263] 34A , in this exemplary embodiment, the serrated shield 1543 comprises a proximal cylindrical portion with tongues that fit into complementary grooves 1544 in the conical backup valve 1541, and a distal portion with a non-resilient serrated strip 1545 that overlaps and forms a conical passageway that is complementary to the conical backup valve 1541. The serrated shield 1543 acts as a barrier to prevent the softer resilient conical backup valve 1541 immediately below from being punctured when a sharp or multi-pronged instrument (such as a needle or clip applier instrument) is inserted. The serrated strip 1545 is hinged proximally and presses against the resilient conical valve 1541 beneath it when such an instrument is inserted, preventing the conical backup valve 1541 from being punctured. The serrated shield 1543 can be made of a flexible, high Shore hardness, injection-molded plastic such as polyethylene or polypropylene. In other embodiments, the serrated shield 1543 can be flat, floating, jagged, wavy, layered, or have any combination thereof as known and described in the prior art.

[0264] As described in the previous embodiment, the conical backup valve 1541 has a central bore 1546 with an inner diameter that can be stretched to accommodate both the smallest instrument 2511 and the largest instrument 2533 and then contracted using its elastic properties to return to its original inner diameter.

[0265] In alternative embodiments, the serrated shield 1543 can be attached to the conical backup valve 1541 in a variety of different ways, such as with adhesive or epoxy, an inverted tongue and groove mechanism, or can be overmolded.

[0266] In this embodiment, a large instrument 2533, such as a clip applier, is inserted into the constant diameter cannula 1520 and is concentrically guided by the conical opening of the valve cap 1537, which contacts the serrated shield 1543, thereby shielding the conical backup valve 1541 and concentrically guiding the instrument 2533 distally toward the bore opening 1546 of the conical backup valve 1541, which then expands the diameter of the bore 1546 to correspond to the diameter of the instrument 2533, while simultaneously creating a tight seal that prevents gas from escaping.

[0267] The serrated shield 1543 and conical backup valve 1541, and / or the instrument itself, may be lubricated to reduce frictional forces as the instrument is guided axially through the constant diameter cannula 1520.

[0268] With particular reference to FIG. 34B, in this exemplary embodiment, the conical backup valve 1541 has a distal conical section 1547 and a proximal u-shaped section 1548 (shown in cross section even though the contours of the shape extend circumferentially about the axis of the conical backup valve 1541) to allow for vertical movement in the z-direction, and can pivot at different angles to accommodate small instruments being manipulated at different angles through the lumen 1520 of the constant diameter cannula.

[0269] In alternative embodiments, the u-shaped geometry 1548 may be different and may have at least one or more "u" sections. The "u" sections may be accordion-shaped, zigzag in shape, or folded in various ways known in the art.

[0270] In this embodiment, a small instrument 2511, such as a grasping forceps, is inserted into the constant diameter cannula 1520 and guided concentrically, as is a larger instrument 2533, and the diameter of the hole 1546 is stretched to accommodate the instrument 2511 while preventing gas loss.

[0271] With particular reference to Figures 34C-34D, in this exemplary embodiment, the small instrument 2512 is manipulated within the constant diameter cannula 1520 to an angle 2512, pivoting the conical backup valve 1541 so that one side of the proximal U-shaped section 1548 (shown on the left in this figure) extends fully out 1551, moving the same side of the distal conical section 1547 distally, while the opposite side of the proximal U-shaped section 1548 (shown on the right in this figure) bends further 1552 and converges under the valve cap 1537, allowing the opposite side of the distal conical section 1547 to move proximally, such that the entire distal conical section 1547 of the conical backup valve 1541 and complementary serrated shield 1543 is in an angled position 1550 with little or no extension.

[0272] Because the outer diameter of the small instrument 2511 is much smaller than the inner diameter of the constant diameter cannula 1520, the small instrument 2511 can be manipulated at different angles, and the conical backup valve 1541 and serrated shield 1543 can pivot accordingly, with the hole 1546 staying tight around the small instrument 2511 and preventing gas loss.

[0273] In an alternative embodiment, the degree of angled small instrument 2512 can be controlled by varying the length and inner diameter of constant diameter cannula 1520 .

[0274] 35A-35D, in this exemplary embodiment, an expansion assembly 1500 having an obturator 1510 and a constant diameter cannula 1520 without a vent hole 1523 is shown, which can be used as a cannula device in its own right and in a manner similar to a conventional trocar.

[0275] With particular reference to Figures 35A-35B, in this particular embodiment, an expansion assembly 1500 is shown without ventilation holes 1523 which may be removed during the manufacturing process, covered with removable tape, or blocked with known sealing materials.

[0276] In an alternative embodiment, the obturator 1510 may include an optical tip and a hollow lumen to allow entry of an endoscope, and thus may be used as an "optical" obturator, and the entire assembly 1500 may be used as an "optical trocar," as known and understood by those skilled in the art.

[0277] In an alternative embodiment, the constant diameter cannula may have surface modifications, such as surface modifications on the rigid elongate member 1300, to provide better fixation.

[0278] With particular reference to Figures 35C-35D, in an exemplary embodiment, a cross-sectional view is shown in which a head 1535, which can be attached and detached by the latch mechanism 1536 described above, houses a conical backup valve 1541, a serrated shield 1543, and a one-way valve 1542, thereby preventing gas leakage through the constant diameter cannula 1520.

[0279] The foregoing disclosure of exemplary embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many variations and modifications of the embodiments described herein will be apparent to those skilled in the art in light of the above disclosure.

[0280] Furthermore, in describing representative embodiments, the specification may present a method and / or process as a particular order of steps. However, to the extent that the method or process does not rely on the particular order of steps described herein, the method or process should not be limited to the particular order of steps described. As one skilled in the art will appreciate, other orders of steps may be possible. Accordingly, the particular order of steps described herein should not be construed as a limitation on the scope of the claims.

[0281] While the invention is susceptible to various modifications and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not limited to the particular forms or methods disclosed, but on the contrary, the invention includes all modifications, equivalents, and alternatives falling within the scope of the appended claims.

Claims

1. a first housing defining a first throughbore aligned along a central axis; a second housing defining a second through hole aligned with the first through hole along the central axis, the second housing being axially movable along the central axis relative to the first housing; a plurality of elongate members cooperatively defining a passageway between proximal and distal ends of the elongate members axially aligned with the first throughbore along the central axis; and a plurality of guide elements on the proximal ends of the elongated members and the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongated members to move outwardly relative to the central axis and away from each other to increase the size of the passageway; The elongate member is configured such that when the proximal end moves radially outward and the distal tip is constrained, the elongate member defines a tapered shape extending from the proximal end toward the distal tip. Cannula device.

2. 2. The cannula device of claim 1, wherein the elongate member is substantially rigid axially between the proximal end and the distal tip so that the elongate member has sufficient column strength to facilitate introduction of the distal tip into the body of a subject, and is semi-rigid radially so that the elongate member is locally deflectable perpendicular to the central axis to enable the elongate member to define the tapered shape.

3. a first housing defining a first throughbore aligned along a central axis; a second housing defining a second through-hole aligned with the first through-hole along the central axis, the first housing being axially movable at least partially into the second through-hole of the second housing along the central axis; a plurality of elongate members cooperatively defining a passageway between proximal and distal ends of the elongate members axially aligned with the first throughbore along the central axis; a plurality of guide elements on the proximal ends of the elongated members and the first and second housings configured to cooperate to cause the proximal ends of the elongated members to move outwardly relative to the central axis and away from each other, increasing the size of the passageway, upon axial movement of the first housing relative to the second housing along the central axis; a resistance member within the first housing adjacent an inlet communicating with the first through-hole, the resistance member configured to receive the secondary device therethrough when the secondary device is inserted into the inlet and first through-hole and to couple axial movement of the first housing to axial movement of the secondary device; A cannula device comprising:

4. 4. The cannula device of claim 3, wherein the resistance member comprises a resilient member extending across the entrance including an opening therethrough having a cross section smaller than an outer cross section of the secondary device, the resilient member resiliently expanding the opening to accommodate insertion of the secondary device while applying friction to the secondary device to couple movement of the first housing to axial movement of the secondary device.

5. The cannula device of claim 4 , wherein the resilient member includes an elastomeric seal.

6. The cannula device of claim 5 , wherein the elastomeric seal is configured to close the opening when the secondary device is removed to provide a fluid-tight seal.

7. 4. The cannula device of claim 3, wherein the resistance member comprises a plurality of deformable elements surrounding the entrance, the deformable elements configured to deform to accommodate insertion of the secondary device while applying friction to the secondary device to couple movement of the first housing to axial movement of the secondary device.

8. 8. The cannula device of claim 7, wherein the deformable element comprises bendable strips spaced apart from one another around the entrance, the strips configured to bend to accommodate insertion of the secondary device while applying friction to the secondary device.

9. 1. A cannula device for use with an obturator comprising: an elongate shaft defining an outer diameter; and an obturator tip at a distal end of the shaft having a cross section larger than the outer diameter, a first housing defining a first throughbore aligned along a central axis; a second housing defining a second through hole aligned with the first through hole along the central axis, the first housing being axially movable along the central axis relative to the second housing; a plurality of elongate members cooperatively defining a passageway between proximal and distal ends of the elongate members axially aligned with the first throughbore along the central axis; and a plurality of guide elements on the proximal ends of the elongated members and the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongated members to move outwardly relative to the central axis and away from each other to increase the size of the passageway; A cannula device, wherein the distal tip of the elongated member includes an internal taper from the passage to the outlet of the elongated member sized to receive a portion of the obturator tip when the shaft is positioned within the passage.

10. 10. The cannula device of claim 9, wherein the obturator tip comprises a proximal region tapering outward from the distal end of the shaft and a distal region tapering inward to a nose of the obturator tip, the taper of the distal tip being configured to receive the proximal region of the obturator tip such that the nose extends from the outlet of the elongate member, and the distal tip of the elongate member presents a substantially smooth outer contour from the elongate member to the nose.

11. 10. The cannula device of claim 9, wherein the elongated member is substantially axially rigid between the proximal end and the distal tip such that the elongated member has sufficient column strength to facilitate introduction of the distal tip into the subject's body, and is radially semi-rigid such that the elongated member is locally deflectable perpendicular to the central axis to accommodate insertion of the obturator tip through the passage until the obturator tip is received by the internal taper of the distal tip of the elongated member.

12. The cannula device of claim 9 , wherein the distal tip of the elongate member has a substantially uniform outer diameter.

13. 10. The cannula device of claim 9, wherein each said distal tip has a barbed outer surface including a blunt proximal surface and a tapered distal surface tapering inward from the blunt proximal surface to the outlet.

14. a first housing defining a first throughbore aligned along a central axis; a second housing defining a second through hole aligned with the first through hole along the central axis, the first housing being axially movable along the central axis relative to the second housing; a plurality of elongate members cooperatively defining a passageway between proximal and distal ends of the elongate members axially aligned with the first throughbore along the central axis; a plurality of guide elements on the elongate member and the proximal ends of the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly relative to the central axis and away from each other to an expanded configuration, increasing the size of the passageway; A cannula device comprising: longitudinal side edges of the elongated members are disposed adjacent to one another to surround the passage when the first and second housings are in a first position before the elongated members are moved outwardly, and the side edges are disposed away from one another when the first and second housings are in a second position in which the elongated members are moved away from one another to increase the size of the passage; The cannula device, wherein the distal tip of the elongate member tapers inwardly to surround the passageway at the first position.

15. The cannula device of claim 14 , wherein the distal tip defines an obturator tip.

16. a first housing defining a first throughbore aligned along a central axis; a second housing defining a second through hole aligned with the first through hole along the central axis, the first housing being axially movable along the central axis relative to the second housing; a plurality of elongate members cooperatively defining a passageway between proximal and distal ends of the elongate members axially aligned with the first throughbore along the central axis; a plurality of guide elements on the proximal ends of the elongated members and the first and second housings configured to cooperate to cause the proximal ends of the elongated members to move outwardly relative to the central axis and away from each other, increasing the size of the passageway, upon axial movement of the first housing relative to the second housing along the central axis; a membrane overlying the elongate members from the proximal end at least partially toward the distal tip to provide a fluid-tight seal to prevent gas within the passage from escaping between the elongate members; A cannula device comprising:

17. 17. The cannula device of claim 16, wherein the membrane at least partially covers one or both of the first and second housings to prevent gas within the first and second through holes from escaping through side walls of the first and second housings.

18. The cannula device of claim 17 , wherein the membrane substantially encases the first and second housings except for an entrance region.

19. The cannula device of claim 16, wherein each elongate member includes a recess adjacent the distal tip, the distal end of the membrane being received within the recess.

20. 20. The cannula device of claim 19, wherein each distal tip comprises a tapered outer surface tapering inwardly to the outlet of the passageway, the recess being located at a proximal end of the tapered region.

21. 17. The cannula device of claim 16, wherein each distal tip comprises a tapered tip including a blunt proximal surface extending radially outward from the elongate member to an outer edge and a tapered distal surface tapering inward from the outer edge to an exit of the passageway, the distal end of the membrane being attached adjacent the proximal surface.

22. The cannula device of claim 16 , wherein the distal end of the membrane is permanently attached to the elongate member.

23. a first housing defining a first throughbore aligned along a central axis; a second housing defining a second through hole aligned with the first through hole along the central axis, the first housing being axially movable along the central axis relative to the second housing; a plurality of elongated rigid members cooperatively defining a passageway between proximal and distal ends thereof that is axially aligned with the first throughbore along the central axis; a plurality of linkages on the proximal ends of the rigid members and the first housing configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the rigid members to move outwardly relative to the central axis and away from each other, increasing the size of the passageway; A cannula device comprising:

24. 24. The cannula device of claim 23, wherein each linkage comprises a first end rotatably coupled to the proximal end of one of the rigid members and a second end rotatably coupled to the first housing to provide a set of hinges such that the proximal end of the rigid member moves radially outward relative to the second housing when the first housing moves distally relative to the second housing.

25. a first housing defining a first throughbore aligned along a central axis; a second housing defining a second through hole aligned with the first through hole along the central axis, the first housing being axially movable along the central axis relative to the second housing; a plurality of elongate members cooperatively defining a passageway between proximal and distal ends of the elongate members axially aligned with the first throughbore along the central axis; a plurality of guide elements on the proximal ends of the elongated members and the first and second housings configured to cooperate such that axial movement of the first housing in a first direction relative to the second housing along the central axis causes the proximal ends of the elongated members to move outward relative to the central axis to move away from each other, increasing the size of the passageway and expanding the passageway, and thereafter axial movement of the first housing in a second direction opposite the first direction causes the proximal ends of the elongated members to move inward to decrease the size of the passageway; A cannula device comprising:

26. 26. The cannula device of claim 25, further comprising a resistance member within the inlet of one of the first and second housings, the resistance member configured to receive the secondary device therethrough when the secondary device is inserted into the inlet and second through hole and to couple axial movement of the first housing to axial movement of the secondary device.

27. 26. A cannula device according to any one of claims 1 to 10 and claims 12 to 25, wherein the elongate member is substantially rigid axially between the proximal end and the distal tip so that the elongate member has sufficient column strength to facilitate introduction of the distal tip into the body of a subject, and is radially semi-rigid so that the elongate member is deflectable perpendicular to the central axis to allow the proximal end to move radially outward while the distal tip is constrained, such that the elongate member defines a tapered shape extending from the proximal end towards the distal tip.

28. side edges of the elongated members are disposed adjacent to one another to surround the passage when the first and second housings are in a first position prior to outward movement of the elongated members; 26. The cannula device of any one of claims 1 to 25, wherein the side edges are positioned apart from each other when the first and second housings are in a second position in which the elongated members move away from each other, increasing the size of the passageway.

29. 26. A cannula device according to any one of claims 1 to 15 and claims 23 to 25, further comprising a tubular membrane overlying the elongate members from the proximal end at least partially towards the distal tip to provide a fluid-tight seal to prevent gas within the passage from escaping between the elongate members.

30. 30. The cannula device of claim 29, wherein the membrane at least partially covers one or both of the first and second housings to prevent gas within the first and second through holes from escaping through side walls of the first and second housings.

31. 30. The cannula device of claim 29, wherein the membrane substantially encases the first and second housings except for an entrance region.

32. 30. The cannula device of claim 29, wherein each elongate member includes a recess adjacent the distal tip, the distal end of the membrane being received within the recess.

33. 33. The cannula device of claim 32, wherein each distal tip comprises a tapered outer surface tapering radially inward to the outlet of the passageway, the recess being located at a proximal end of the tapered region.

34. 30. The cannula device of claim 29, wherein each distal tip comprises a tapered tip including a blunt proximal surface extending radially outward from the elongate member to an outer edge and a tapered distal surface tapering inward from the outer edge to an exit of the passage, the distal end of the membrane being attached adjacent the proximal region.

35. 35. The cannula device of any one of claims 29 to 34, wherein the distal end of the membrane is permanently attached to the elongate member.

36. 26. The cannula device of any one of claims 1 to 25, wherein each elongate member comprises a plurality of engagement features on an outer surface thereof that engage surrounding tissue to prevent migration of the cannula device.

37. 37. The cannula device of claim 36, wherein the engagement features are spaced apart from one another along the length of each elongate member.

38. The cannula device of claim 36, wherein each engagement feature includes a tapered distal surface and a blunt proximal surface.

39. 26. The cannula device of any one of claims 1 to 25, wherein one of the first and second housings comprises a mount for docking the cannula device to an arm of a robotic surgical system.

40. 26. The cannula device of any one of claims 1 to 25, wherein one of the first and second housings includes a side port in communication with one or both of the first and second through holes.

41. 41. The cannula device of claim 40, wherein the side port includes one or both of a stopcock for an opening and for closing the side port, and a connector for connecting a pressurized gas source coupled to the side port for delivering insufflation gas.

42. 26. The cannula device of any one of claims 1 to 25, wherein the guide element is configured such that the proximal end of the rigid member moves obliquely proximally relative to the first housing and radially outward relative to the second housing when the first housing moves distally along the central axis relative to the second housing.

43. 26. The cannula device of any one of claims 1 to 25, wherein the guide element comprises a first track including an interengaging first tongue and first guide oriented obliquely relative to the central axis, and the second housing and the elongated rigid member comprise a second track including a second tongue and second guide such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the rigid members to move outward relative to the central axis and obliquely relative to the first housing, moving away from each other and increasing the size of the passageway.

44. 44. The cannula device of claim 43, wherein each said rigid member includes a first tongue that slides within a corresponding first guide in the first housing.

45. 45. The cannula device of claim 44, wherein each of the rigid members includes a second tongue that slides within a corresponding second guide in the second housing, the second track being oriented radially relative to the central axis.

46. 23. The cannula device of any one of claims 1 to 22, wherein axial movement of the first housing relative to the second housing in a first direction along the central axis moves the proximal ends of the elongated members outward relative to the central axis and away from each other, increasing the size of the passage and dilating the passage, and then axial movement of the first housing in a second direction opposite the first direction moves the proximal ends of the elongated members inward to decrease the size of the passage.

47. 26. The cannula device of any one of claims 1 to 25, wherein the first and second housings include cooperating tongues and grooves that allow the first housing to move relative to the second housing along the central axis without rotating.

48. 26. A cannula device according to any one of claims 1 to 25, further comprising one or more seals within the first housing to seal the passageway but allow one or more devices to be inserted into the passageway through the first through-hole.

49. 49. The cannula device of claim 48, wherein the one or more seals prevent pressurized gas from escaping the through-hole and comprise a one-way valve configured to accommodate insertion of a secondary device therethrough.

50. 50. The cannula device of claim 49, wherein the one-way valve comprises a cross-slit valve.

51. 51. The cannula device of claim 49 or 50, wherein the one or more seals further comprise a backup valve adjacent the one-way valve configured to prevent pressurized gas from escaping through the through-hole when a secondary device is inserted therethrough.

52. 26. The cannula device of any one of claims 1 to 25, further comprising a first obturator configured to be inserted into the first through-hole through an entire undilated passage so that a tip of the first obturator is exposed before inserting the cannula device into tissue.

53. 53. The cannula device of claim 52, wherein a second obturator having a larger diameter than the first obturator is configured to engage the first housing when inserted into the through hole to move the first housing distally relative to the second housing, moving the elongated members away from each other and increasing the size of the passageway.

54. 54. The cannula device of claim 53, wherein the first housing includes a resistance member disposed across the first through hole, and the second obturator is configured to engage the resistance member to couple axial movement of the first housing to corresponding movement of the second obturator.

55. 55. The cannula device of claim 54, wherein the resistance member comprises a seal formed from an elastic membrane disposed across the first through hole, the membrane having a hole therethrough that can be expanded when an obturator is inserted through the membrane into the first through hole, and the membrane elastically closes the hole when the obturator is removed.

56. 26. A cannula device according to any one of claims 1 to 25, wherein the rigid member defines a curved or tapered inner surface extending between its proximal and distal ends that at least partially defines the passageway.

57. 26. The cannula device of any one of claims 3 to 25, wherein the elongate members are configured such that axial movement of the first housing relative to the second housing causes the proximal ends of the elongate members to move away from each other without substantially moving the distal ends of the rigid members such that the rigid members taper inwardly from the proximal ends to the distal ends.

58. 26. The cannula device of any one of claims 1-15 and 22-25, further comprising a resilient membrane surrounding the rigid members to seal the passageway along the length of the rigid members when the rigid members move away from each other.

59. 26. A cannula device according to any one of claims 1 to 15 and claims 22 to 25, further comprising an elastic membrane extending at least partially between adjacent rigid members between the proximal and distal ends of the rigid members.

60. 60. The cannula device of claim 59, wherein the elastic membrane extends proximally from the distal end of adjacent rigid members a predetermined distance to provide a low friction interface with tissue to facilitate insertion of the rigid members through tissue.

61. 1. A system for introducing one or more instruments into a patient's body to perform a procedure, comprising: i. A cannula device comprising: a. first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; b. a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passages between proximal and distal ends of the elongate members axially aligned with the throughbore along the central axis; and c. a plurality of guide elements on the proximal ends of the elongated members and the first and second housings configured to cooperate to cause the proximal ends of the elongated members to move outwardly relative to the central axis and away from each other to increase the size of the passageway upon axial movement of the first housing relative to the second housing along the central axis, the distal tip of the elongated member including an interior that tapers from the passageway to the outlet of the elongated member such that the outlet has a diameter greater than the passageway; a cannula device comprising: ii. an obturator, a. an elongate shaft configured to be inserted into the passageway and through the throughbore, the shaft defining an outer diameter; b. an obturator tip at a distal end of the shaft having a cross-section larger than the outer diameter, the taper at the distal tip being sized to receive a portion of the obturator tip when the shaft is positioned within the passageway.

62. 62. The system of claim 61, wherein the obturator tip comprises a proximal region tapering outward from the distal end of the shaft and a distal region tapering inward to a nose of the obturator tip, the taper of the distal tip being formed to receive the proximal region of the obturator tip so that the nose extends from the outlet of the elongate member.

63. 63. The system of claim 62, wherein the distal tip of the elongate member presents a substantially smooth outer contour from the elongate member to the nose.

64. 64. The system of claim 63, wherein the nose comprises one of a sharp nose and a dolphin nose, or the obturator tip comprises a Veress needle.

65. 62. The system of claim 61, wherein the obturator comprises a proximal portion or handle that engages with a portion of the second housing to create a stop feature that controls the distance the obturator tip can advance distally within the passageway.

66. 1. A system for introducing one or more instruments into a patient's body to perform a procedure, comprising:

42. A cannula device according to claim 41 ; A system comprising: a positioning probe holding one or more track elements, the positioning probe having a distal end sized for introduction into a passageway of the cannula device at a first position to enable the cannula device to be introduced into the body of a subject using the probe.

67. 1. A system for introducing one or more instruments into a patient's body to perform a procedure, comprising: i. A cannula device comprising: a. first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; b. a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passages between proximal and distal ends of the elongate members axially aligned with the throughbore along the central axis; and c) a cannula device comprising: a plurality of guide elements on the proximal ends of the elongate members and the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly relative to the central axis and away from each other to increase the size of the passageway; ii. a secondary device sized for insertion through the throughbore and into the passageway, the secondary device configured to engage the first housing to move the first housing distally relative to the second housing, moving the elongate members apart and increasing the size of the passageway; A system comprising:

68. The secondary device is an elongate tubular member having a proximal end, a distal end, and a lumen extending between the proximal and distal ends; 68. The system of claim 67, comprising an obturator received within the lumen such that a distal tip of the obturator extends beyond the distal end of the tubular member.

69. 69. The system of claim 68, wherein one of the first and second housings includes a side port that communicates with one or both of the first and second through holes, and the tubular member includes one or more openings in its side wall that communicate with the lumen such that a pressurized gas source connected to the side port can deliver gas into the lumen through the one or more openings.

70. 70. The system of claim 69, wherein the side port comprises one or both of a stopcock for an opening and for closing the side port, and a connector for connecting a pressurized gas source connectable to the side port.

71. 70. The system of claim 68 or 69, further comprising one or more seals adjacent an inlet in communication with said through hole for sealing said through hole.

72. 72. The system of claim 71, wherein the one or more seals comprise a one-way valve configured to prevent pressurized gas from escaping through the through-hole.

73. 73. The system of claim 72, wherein the one-way valve comprises a cross-slit valve.

74. 74. The system of claim 72 or 73, wherein the one or more seals further comprise a backup valve adjacent the one-way valve configured to prevent pressurized gas from escaping from the through-hole when a secondary device is inserted therethrough.

75. 76. The system of claim 75, wherein the backup valve includes an opening therethrough to accommodate insertion of the secondary device while preventing pressurized gas from escaping through the through-hole.

76. 69. The system of claim 68, further comprising one or more seals within the proximal end of the tubular member to seal the lumen.

77. 77. The system of claim 76, wherein the one or more seals prevent pressurized gas from escaping the lumen and comprise a one-way valve configured to accommodate insertion of an instrument into the lumen through the one-way valve.

78. 78. The system of claim 77, wherein the one or more seals further comprise a backup valve adjacent the one-way valve configured to prevent pressurized gas from escaping through the through-hole when an instrument is inserted through the one-way valve.

79. 77. The system of claim 76, wherein at least a portion of the tubular member is removable to remove the one or more seals from the proximal end to provide for rapid degassing or analyte removal without interference from the seal.

80. 69. The system of claim 68, wherein the distal tip of the obturator comprises a sharp tip configured to penetrate tissue to create an entry hole in a subject's body and facilitate insertion of the cannula device through the tissue.

81. 69. The system of claim 68, wherein the tubular member includes a hub or handle at its proximal end.

82. 69. The system of claim 68, wherein the obturator is removable from the tubular member to provide an open lumen for introducing one or more instruments through the lumen and into the patient's body.

83. 68. The system of claim 67, wherein the secondary device comprises a first elongate member having a first outer diameter configured to move the elongate members away from each other to expand the passageway to a first expanded configuration, the system further comprising a second elongate member having a second outer diameter greater than the first outer diameter, the second elongate member insertable into the cannula device after removing the first elongate member to expand the passageway to a second expanded configuration.

84. 68. The system of claim 67, wherein the elongate members are biased toward one another such that removal of the tubular member causes the elongate members to move inward toward one another to automatically reduce the size of the passageway.

85. 68. The system of claim 67, wherein the first housing includes a seal configured to prevent backflow of fluid proximally through the passage and the through hole, and the elongated member is configured to engage the seal to couple axial movement of the first housing to movement of the elongated member.

86. 68. The system of claim 67, wherein the first housing comprises a resistance member disposed across the through hole, and the elongated member is configured to engage the resistance member to couple axial movement of the first housing to movement of the elongated member.

87. 87. The system of claim 86, wherein the resistance member comprises a seal formed from an elastic membrane disposed across the through hole, the membrane having a hole therethrough that can be expanded when the elongated member is inserted through the membrane into the through hole, and the membrane elastically closes the hole when the elongated member is removed.

88. 87. The system of claim 86, wherein the resistance member comprises a seal disposed across the through hole, the seal having a hole therethrough that can expand when an obturator is inserted into the through hole through a membrane, the seal resisting insertion through the hole such that insertion of the elongated member causes the first housing to move distally relative to the second housing, moving rigid members away from each other to automatically expand the passage during insertion of the elongated member.

89. 87. The system of claim 86, wherein the resistance member comprises one or more seals disposed across the through hole configured to resiliently expand when the elongated member is inserted into the through hole, the one or more seals frictionally and slidably engaging an outer surface of the elongated member such that insertion of the elongated member causes the first housing to move distally relative to the second housing, moving the rigid members away from each other to automatically expand the passage during insertion of the elongated member.

90. 90. The system of claim 89, wherein when the elongated member is removed from the cannula device, the one or more seals are configured to frictionally and slidably engage the outer surface of the elongated member to move the first housing proximally relative to the second housing and move the rigid members inward toward each other during removal of the elongated member, automatically reducing the passageway.

91. 1. A system for introducing one or more instruments into a patient's body to perform a procedure, comprising: i. A cannula device comprising: a. first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; b. a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passages between proximal and distal ends of the elongate members axially aligned with the throughbore along the central axis; and c) a cannula device comprising: a plurality of guide elements on the proximal ends of the elongate members and the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly relative to the central axis and away from each other to increase the size of the passageway; ii. an obturator removably received through the through-hole and passageway with a rigid member at a reduced profile such that a distal tip of the obturator extends beyond the distal end of the elongate member, the distal tip of the obturator being sharpened to pierce tissue and create an entry hole in a subject's body to facilitate insertion of the cannula device through tissue; a set of secondary members sized for insertion through the throughbore and into the passageway, each secondary member configured to engage the first housing to move the first housing distally relative to the second housing to move the elongate members away from each other and increase the size of the passageway.

92. 92. The system of claim 91, wherein the set of secondary members comprises a first secondary member having a first outer diameter configured to move the elongated members away from each other to expand the passageway to a first expanded configuration, and a second secondary member having a second outer diameter greater than the first outer diameter, the second secondary member being insertable into the cannula device after removing the first elongated member to expand the passageway to the second expanded configuration.

93. 1. A system for introducing one or more instruments into a patient's body to perform a procedure, comprising: i. A cannula device comprising: a) first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing, one of the first and second housings including a side port in communication with the throughbore such that a pressurized gas source connected to the side port can deliver gas into the throughbore through one or more openings; b. a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passages between proximal and distal ends of the elongate members axially aligned with the throughbore along the central axis; and c) a cannula device comprising: a plurality of guide elements on the proximal ends of the elongate members and the first and second housings configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly relative to the central axis and away from each other to increase the size of the passageway; ii. an elongate tubular member having a proximal end, a distal end sized for insertion into the passageway through the through-hole, and a lumen extending between the proximal and distal ends, the tubular member having one or more openings in a side wall thereof communicating with the lumen such that pressurized gas introduced through the side port passes through the one or more openings and into the lumen.

94. 94. The system of claim 93, further comprising one or more seals adjacent an inlet communicating with the through hole for sealing the through hole when the tubular member is inserted into or removed from the through hole.

95. 95. The system of claim 93 or 94, further comprising one or more seals within the proximal end of the tubular member.

96. 96. The system of claim 95, wherein the one or more seals comprise a one-way valve configured to prevent pressurized gas from escaping the lumen but to accommodate insertion of a secondary device therethrough.

97. 97. The system of claim 96, wherein the one-way valve comprises a cross-slit valve.

98. 98. The system of claim 96 or 97, wherein the one or more seals further comprise a backup valve adjacent to the one-way valve configured to prevent pressurized gas from escaping the lumen when a secondary device is inserted therethrough.

99. 96. The system of claim 95, wherein at least a portion of the tubular member is removable to remove the one or more seals from the proximal end to provide for rapid deairing.

100. 94. The system of claim 93, further comprising an obturator received within the lumen such that a distal tip of the obturator extends beyond the distal end of the tubular member, the obturator and tubular member configured to engage the first housing to move the first housing distally relative to the second housing, moving the elongated members away from each other and increasing the size of the passage.

101. 1. A method of performing a medical procedure within a subject's body, comprising: providing a cannula device comprising: first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; and a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passages between proximal and distal ends thereof that are axially aligned with the throughbore along the central axis; inserting the distal tip of the elongate member through tissue into the subject's body; expanding the cannula device by moving the first housing relative to the second housing along the central axis, whereby the proximal ends of the elongate members move outwardly relative to the central axis, moving the elongate members away from each other and increasing the size of the passageway; and introducing one or more instruments through the expanded cannula device to perform the medical procedure within the subject's body.

102. connecting a source of insufflation gas to a side port of said cannula device; delivering insufflation gas from the source through the through-holes and passageways into the subject's body; 102. The method of claim 101, further comprising:

103. 103. The method of claim 102, wherein the insufflation gas is delivered prior to expanding the cannula device, and the cannula device is expanded without allowing the insufflation gas to escape from the subject's body.

104. 102. The method of claim 101, wherein the cannula device further comprises a plurality of guide elements on the proximal ends of the elongate members, and wherein the first and second housings are configured to cooperate such that axial movement of the first housing relative to the second housing along the central axis causes the proximal ends of the elongate members to move outwardly relative to the central axis and away from each other, increasing the size of the passageway.

105. 102. The method of claim 101, wherein the cannula is expanded to open the passageway to a diameter of between 3 mm and 12 mm.

106. 102. The method of claim 101, wherein the step of inserting the distal tip of the elongate member through tissue into the subject's body creates an entry hole through tissue into the subject's body.

107. 102. The method of claim 101, further comprising inserting an obturator through the passageway to expose an obturator tip before inserting the distal tip of the elongate member through tissue, the obturator tip being used to penetrate the tissue to create an entry hole in the subject's body.

108. 108. The method of claim 107, further comprising removing the obturator from the cannula device before expanding the cannula device.

109. 102. The method of claim 101, wherein expanding the cannula device includes inserting a secondary elongate member through the through hole and into the passageway, the secondary elongate member engaging the first housing to move the first housing distally relative to the second housing, moving the elongate members away from each other and increasing the size of the passageway.

110. 110. The method of claim 109, wherein the secondary member comprises an elongate tubular member having a proximal end, a distal end, and a lumen extending between the proximal and distal ends, and an obturator received within the lumen such that a distal tip of the obturator extends beyond the distal end of the tubular member, and the tubular member and obturator are simultaneously inserted into the passage through the through hole to move the first housing distally relative to the second housing, moving the elongate members away from each other and increasing the size of the passage.

111. The method of claim 110, further comprising the step of removing the obturator from the lumen after inserting the tubular member and obturator through the through-hole and passage, wherein the one or more instruments are introduced into the subject's body through the lumen.

112. 110. The method of claim 109, wherein the first housing includes a seal configured to prevent backflow of fluid proximally through the passage and the through hole, and when the secondary member is inserted into the through hole, the secondary member engages the seal to couple axial movement of the first housing to movement of the secondary member.

113. 110. The method of claim 109, wherein when the secondary member is inserted into the through hole, the secondary member engages a resistance member within the first housing to couple axial movement of the first housing to movement of the secondary member.

114. 114. The method of claim 113, wherein the resistance member comprises a seal formed from an elastic membrane disposed across the through hole, the membrane having a hole therethrough that expands when the secondary member is inserted through the membrane into the through hole, and the membrane elastically closes the hole when the secondary member is removed.

115. 114. The method of claim 113, wherein the resistance member comprises a seal disposed across the through hole, the seal having a hole therethrough that expands when the secondary member is inserted through the membrane into the through hole, and the seal resists insertion through the hole such that during insertion of the secondary member, insertion of the secondary member causes the first housing to move distally relative to the second housing, moving the elongated members away from each other and automatically expanding the passage.

116. 114. The method of claim 113, wherein the resistance member comprises one or more seals disposed across the through hole that elastically expand when the secondary member is inserted into the through hole, the one or more seals frictionally and slidably engaging an outer surface of the secondary member such that insertion of the secondary member moves the elongated members such that the first housing moves distally relative to the second housing and away from each other, automatically expanding the passage during insertion of the secondary member.

117. 117. The method of claim 116, wherein when the secondary member is removed from the cannula device, the one or more seals frictionally and slidably engage the outer surface of the secondary member to move the first housing proximally relative to the second housing and move the elongated members inward toward each other to automatically reduce the passageway during removal of the secondary member.

118. 1. A method of performing a medical procedure within a subject's body, comprising: providing a cannula device comprising: first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing; and a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passages between proximal and distal ends thereof that are axially aligned with the throughbore along the central axis; inserting the distal tip of the elongate member through tissue into the subject's body; inserting a first elongated tubular member through the through-hole and passageway to move the first housing relative to the second housing along the central axis, thereby moving the proximal ends of the elongated members outwardly relative to the central axis, moving the elongated members away from each other and increasing the size of the passageway; and introducing one or more instruments through the first tubular member to perform the medical procedure within the subject's body.

119. removing the first elongated tubular member from the cannula device; moving the first housing relative to the second housing along the central axis, thereby moving the proximal ends of the elongated members outwardly relative to the central axis, moving the elongated members away from each other, and inserting a second elongated member through the throughbore and passageway to further increase the size of the passageway; 119. The method of claim 118, further comprising:

120. 1. A method of performing a medical procedure within a subject's body, comprising: connecting a cannula device to an arm of a robotic surgical system, the cannula device comprising first and second housings defining a throughbore along a central axis, the first housing being axially movable along the central axis relative to the second housing, and a plurality of elongate members extending distally from the first and second housings, the elongate members cooperatively defining passages between proximal and distal ends of the elongate members that are axially aligned with the throughbore along the central axis; inserting the distal tip of the elongate member into the subject's body through tissue using the arm; expanding the cannula device by moving the first housing relative to the second housing along the central axis, thereby moving the proximal ends of the elongate members outwardly relative to the central axis, moving the elongate members away from each other and increasing the size of the passageway; and introducing one or more instruments through the expanded cannula device to perform the medical procedure within the subject's body.

121. 121. The method of claim 120, wherein the cannula device is expanded by manually moving the first housing relative to the second housing.

122. 121. The method of claim 120, wherein the cannula device is expanded by the robotic arm moving the first housing relative to the second housing.

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