Balancing features for reusable trocars

Abstract

The surgical access device assembly includes a cannula hub and a cannula tube. The cannula tube extends distally from the cannula hub along a longitudinal axis. The cannula tube defines a working channel. The cannula tube includes a tissue engagement feature and a balancing feature. The balancing feature is configured to promote lateral stability of the cannula tube and the cannula hub relative to a wall of a patient's body cavity. The balancing feature includes a proximal portion of the cannula tube having a first wall thickness. The balancing feature also includes a distal portion of the cannula tube having a second wall thickness greater than the first wall thickness. At least a portion of the proximal portion is proximal to the tissue engagement feature. At least a portion of the distal portion is distal to the tissue engagement feature.

Description

Technical Field

[0001] (Priority) This application claims the benefit of U.S. Provisional Patent Application No. 63 / 018,558, filed May 1, 2020, entitled "Balancing Feature for Reusable Trocar".

Background Art

[0002] Some surgical procedures may require a clinician to access a surgical site through a patient's abdominal cavity. To obtain such access, first, an opening is formed through the abdominal wall tissue above the abdominal cavity. In some surgical procedures (referred to as "laparoscopic" or "endoscopic" surgeries), a relatively small opening is created through the abdominal wall tissue, and then the surgical site is accessed with an elongated instrument inserted through an access device commonly referred to as a "trocar" positioned within the opening. Conventional trocars generally include a cannula assembly and an obturator removably received within the working channel of the cannula assembly. In use, the obturator is mated with the cannula assembly, and the combined structure (i.e., the trocar) is directed downward by the clinician through the patient's abdominal wall, such that the distal ends of the obturator and the cannula assembly extend into the abdominal cavity. The clinician then withdraws the obturator from the cannula assembly so that a surgical instrument can be directed downward through the working channel of the cannula assembly to access the surgical site.

[0003] Trocars, merely exemplary variations of their components, and other types of surgical access devices are disclosed in U.S. Patent No. 7,981,092 entitled "Vibratory Trocar" issued on July 19, 2011, U.S. Patent No. 8,226,553 entitled "Access Device with Insert" issued on July 24, 2012, U.S. Patent No. 8,251,900 entitled "Surgical Access Devices and Methods Providing Seal Movement in Predefined Paths" issued on August 28, 2012, U.S. Patent No. 8,579,807 entitled "Absorbing Fluids in a Surgical Access Device" issued on November 12, 2013, U.S. Patent No. 8,568,362 entitled "Surgical Access Device with Sorbents" issued on October 29, 2013, U.S. Patent No. 8,636,686 entitled "Surgical Access Device" issued on January 28, 2014, U.S. Patent No. 8,690,831 entitled "Gas Jet Fluid Removal in a Trocar" issued on April 8, 2014, and U.S. Patent Application Publication No. 2019 / 0000496 entitled "Method of Suturing a Trocar Path Incision" published on January 3, 2019. The disclosure of each of the above-cited U.S. patents and U.S. patent application publications is hereby incorporated by reference into this specification.

[0004] Various types of surgical instruments, including surgical access devices and end effectors, and other related components have been made and used, but prior to the present inventors, no one is believed to have made or used the inventions recited in the appended claims.

Brief Description of the Drawings

[0005] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description of the invention given above and the detailed description of the embodiments below, serve to explain the principles of the invention.

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[0006] The drawings are not intended to limit in any way, and it is contemplated that various embodiments of the present invention may be implemented in various other ways, including those not necessarily depicted in the drawings. The accompanying drawings, which are incorporated herein and form a part hereof, illustrate some aspects of the present invention and serve to explain the principles of the present invention in conjunction with the description. However, it is understood that the present invention is not limited to the exact arrangements shown.

DETAILED DESCRIPTION OF THE INVENTION

[0007] The following description of specific embodiments of the invention should not be used to limit the scope of the invention. Other embodiments, features, aspects, embodiments, and advantages of the invention will become apparent to those skilled in the art from the following description, which is one of the best modes contemplated for practicing the invention by way of illustration. As will be understood, the invention is capable of other different and distinct aspects without departing from the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

[0008] For purposes of clarity in this disclosure, the terms “proximal” and “distal” are defined herein with respect to a surgeon or other operator holding a surgical device. The term “proximal” refers to the position of an element that is closer to the surgeon, and the term “distal” refers to the position of an element that is farther from the surgeon. Also, to the extent that spatial terms such as “above,” “below,” “upper,” “lower,” “vertical,” “horizontal,” etc. are used herein with reference to the drawings, it will be understood that such terms are used for illustrative descriptive purposes only and are not intended to be limiting or absolute in any way. In that regard, it will be understood that surgical instruments such as those disclosed herein may be used in a variety of orientations and positions not limited to those illustrated and described herein.

[0009] Furthermore, terms such as “about,” “substantially,” etc. used herein in relation to any numerical values, or ranges of numerical values, are intended to include a suitable margin of error that allows the referenced exact value, as well as the referenced feature, or combination of features, to function for the intended purposes described herein.

[0010] I. Exemplary Single-Use and Reusable Trocars Figures 1-5 illustrate exemplary surgical access devices in the form of a single-use first trocar (10) and a reusable second trocar (110), each configured to provide access to a surgical site in laparoscopic surgery. Each trocar (10, 110) includes a cannula assembly (12, 112) having a working channel (14, 114) and an obturator (16, 116) configured to be removably inserted coaxially into the working channel (14, 114), such that the assembled trocar (10, 110) can be directed distally through the patient's abdominal wall, as described below in connection with FIGS. 3A-3D, for example.

[0011] A. Exemplary single-use trocar As shown in FIGS. 1-2, the cannula assembly (12) of the single-use trocar (10) includes a cannula (20) and a seal housing (30). The cannula (20) and the seal housing (30) cooperate to define a working channel (14) that extends longitudinally along the central axis (A) of the trocar (10). In particular, the working channel (14) is defined by the lumen of the cannula (20) that communicates with the hollow interior of the seal housing (30). The cannula assembly (12) is configured to receive a distally elongate surgical instrument through the working channel (14) to provide access to a surgical site within the patient's abdominal cavity. As described in more detail below, the seal housing (30) houses a pair of seal structures that define a seal assembly configured to maintain insufflation of the patient's abdominal cavity while allowing passage of surgical instruments and tissue fragments along the working channel (14).

[0012] The cannula (20) of this variant may include, at its proximal end, a bell-shaped hub (not shown) and an elongated cylindrical tube (22) that extends distally from the hub and terminates at an angled cannula tip (24). The outer surface of the cannula tube (22) includes a plurality of tissue gripping features in the form of annular ribs (26) disposed axially along an inner portion of the cannula tube (22). The ribs (26) are configured to grip a layer of abdominal wall tissue into which the cannula (20) is inserted, thereby assisting in stabilizing the cannula (20) axially and radially while the cannula (20) is positioned within an opening formed in the patient's abdominal wall.

[0013] More specifically, the tissue gripping ribs (26) of the present embodiment are formed as annular scallops in the sidewall of the cannula tube (22) such that each rib (26) tapers radially inwardly in the distal direction from the radially outermost edge of the rib (26). Accordingly, the radially outermost edge of the rib (26) is generally coplanar with the non-ribbed proximal and distal portions of the cannula tube (22). The resulting configuration of the ribs (26) facilitates the advancement of the cannula tube (22) through the tissue layer in the distal direction and resists the withdrawal of the cannula tube (22) through the tissue layer in the reverse proximal direction. Advantageously, this configuration protects against the unintentional withdrawal of the cannula tube (22) from the patient's abdominal wall during surgery. However, it will be appreciated that the cannula tube (22) may be provided with various other types of tissue gripping features in other variants of the trocar (10). For example, the cannula tube (22) may include tissue gripping features in the form of one or more helical ribs that extend around at least an inner portion of the cannula tube (22) and are scalloped similar to the ribs (26).

[0014] The seal housing (30) of the cannula assembly (12) includes a proximal housing portion (32) and a distal housing portion (34) to which the proximal housing portion (32) is removably attached. The proximal housing portion (32) includes a proximal head (36) and a distal base (38) fixed together. The distal housing portion (34) includes a distal shroud (40) that surrounds a proximal hub (not shown) of the cannula (20), a cap plate (42) fixed to the proximal end of the distal shroud (40), and a latch ring (44) rotatably disposed therebetween and having a radially outwardly projecting tab (46). The latch ring (44) is selectively rotatable about the central axis (A) of the trocar (10) via the tab (46) between a locked position and an unlocked position. In the locked position, the latch ring (44) locks the proximal housing portion (32) to the distal housing portion (34). In the unlocked position, the latch ring (44) allows the proximal housing portion (32) to be separated from the distal housing portion (34) to provide direct access, for example, to a distal seal structure (not shown) housed within the distal housing portion (34). In some variations, the distal shroud (40) may be integrally formed with the proximal end of the cannula tube (22) such that the distal shroud (40) is a component of the cannula (20).

[0015] Although not shown, the proximal housing portion (32) houses a proximal (or "outer") seal structure and the distal housing portion (34) houses a distal (or "inner") seal structure, both being disposed along the central axis (A) of the trocar (10). The proximal and distal seal structures cooperate to define a seal assembly that allows passage of surgical instruments and tissue fragments along the working channel (14) while maintaining insufflation of the patient's abdominal cavity during a surgical procedure. For example, the proximal seal structure may include an annular seal member configured to sealingly engage the shaft of a laparoscopic surgical instrument directed through the working channel (14). The distal seal structure may include a duckbill seal member configured to maintain the sealed working channel (14) described in the absence of a surgical instrument shaft.

[0016] The cannula assembly (12) is operably coupled to the proximal end of the cannula (20) and further includes a blowing port (50) having an adjustable valve in the form of a stopcock (52). The blowing port (50) is configured to direct a blowing fluid, such as carbon dioxide, distally from a fluid source (not shown) through the working channel (14) into the patient's abdominal cavity, thereby expanding (or "blowing") the cavity with the fluid. This expansion of the abdominal cavity creates additional space for performing laparoscopic surgery with improved ease.

[0017] As shown in FIGS. 1 and 2, the obturator (16) of the trocar (10) includes a proximal head (60), an elongated cylindrical shaft (62) extending distally from the head (60), and a tapered distal tip (64). The obturator shaft (62) is configured to be received within the working channel (14) of the cannula assembly (12) such that the obturator tip (64) extends distally through the cannula tip (24). The obturator head (60) includes a domed upper body (66), a base plate (68), and an operable latch member (70) including a pair of latch arms (72) and a corresponding pair of latch buttons (74). The latch arms (72) are configured to be captured within respective slots (not shown) formed in the upper surface of the seal housing head (36) for coupling the obturator (16) to the cannula assembly (12). The latch buttons (74) are operable to release the latch arms (72) from the slots, thereby enabling separation of the obturator (16) from the cannula assembly (12). The obturator (16) further includes a central passageway (76) extending longitudinally therethrough through the obturator head (60) and obturator shaft (62) and configured to receive an endoscope (not shown) therein to provide visualization during insertion of the trocar (10) through the patient's abdominal wall. The clamp lever (78) of the obturator head (60) is pivotable to selectively secure the endoscope within the central passageway (76). The central passageway (76) and clamp lever (78) are merely optional features and may be omitted from the obturator (16) in other variations.

[0018] The cannula assembly (12) and the obturator (16) can be constructed to be disposed of after single use with a patient. In other variations, one or more components of the trocar (10) can be suitably constructed to withstand sterilization and multiple reuses, as will be described in more detail below, for example, in connection with the trocar (110) of FIGS. 4-5.

[0019] B. Exemplary Deployment of a Trocar within a Patient's Abdomen FIGS. 3A-3D illustrate an exemplary method of accessing a patient's peritoneal cavity (1) through the patient's abdominal wall (2) using the trocar (10) described above. It will be appreciated that the abdominal wall (2) includes an outer surface layer and an inner deep layer. Generally, the surface layer includes an outer layer of skin (3) and an inner layer of fat (4). On the other hand, the deeper layer includes an alternative layer of muscle (5) and fascia (6), which is more highly tensioned, fibrous, and flexible than the surface layer.

[0020] As shown in FIG. 3A, with the occluder (16) received within the cannula assembly (12) and connected to the seal housing (30), the clinician operates the trocar (10) via the occluder head (60) and the seal housing (30), rotating the trocar (10) back and forth while pressing the distal end of the occluder (64) inwardly against the skin (3) and in the direction of the peritoneal cavity (1). As shown in FIG. 3B, by continuing to press the trocar (10) inwardly, the distal end of the occluder (64) and the distal end of the cannula (24) are further directed distally through the fat layer (4) and fascia (5) and into the cavity (1). As described above, this step can be facilitated by visualization provided by an endoscope (not shown) mounted within the occluder (16). When the cannula (20) reaches the desired insertion depth into the cavity (1), the clinician releases the occluder head (60) from the seal housing (30) via depression of the latch button (74) and then, as shown in FIG. 3C, withdraws the occluder (16) proximally from the cannula assembly (12). Thereby, the working channel (14) of the cannula assembly (12) becomes free to receive surgical instruments distally therethrough for performing laparoscopic surgery. As described above, the tissue engaging ribs (26) provided on the cannula tube (22) grip the layers of tissue (3, 4, 5) of the abdominal wall (2), thus providing a cannula assembly (12) having at least a minimum of stability with respect to the abdominal wall (2). At the completion of the laparoscopic surgery, the clinician, as shown in FIG. 3D, grips the seal housing (30) and withdraws the cannula assembly (12) proximally from the abdominal wall (2).

[0021] C. Exemplary Reusable Trocar Having a Disposable Seal Assembly In some cases, it may be desirable to configure the trocar such that one or more of its components can be sterilized and reused for multiple surgical procedures, while one or more other components can be easily and economically disposed of and replaced after each procedure. FIGS. 4 - 5 show another exemplary trocar (110) configured in such a manner and having a structure and function similar to the trocar (10) described above, except as otherwise separately described below.

[0022] Similar to the trocar (10), the trocar (110) includes a working channel (114) and a cannula assembly (112) having an obturator (116) configured to be coaxially inserted into the cannula assembly (112) along the working channel (114). The cannula assembly (112) includes a cannula (120) having a bell-shaped hub (122) at its proximal end and an elongated cylindrical tube (124) extending distally from the hub (122) and terminating at an angled cannula tip (126). The outer surface of the cannula tube (124) includes a plurality of tissue gripping features in the form of annular ribs (128) that are axially disposed along the inner portion of the cannula tube (124) and are similar to the ribs (26) described above.

[0023] The cannula assembly (112) further includes a seal assembly (130). Unlike the seal assembly defined by the seal housing (30) of the trocar (10), the seal assembly (130) is constructed as a modular replaceable unit configured to releasably mate with the proximal hub (122) of the cannula (120). As best shown in FIG. 5, the seal assembly (130) of this embodiment generally includes an upper frame member (132), an intermediate frame member (134), and a lower frame member (136) fixed to each other in a coaxial arrangement. Although not shown, the proximal (or "outer") seal structure is supported within the upper frame member (132), and the distal (or "inner") seal structure is supported within the lower frame member (136). Such seal structures may be similar in structure and function to the proximal and distal seal structures of the trocar (10) described above. The seal assembly (130) further includes a blow port (140) having an adjustable valve in the form of a stopcock (142).

[0024] The lower portion of the seal assembly (130) of the blow port (140) is configured to seat within the proximal hub (122) of the cannula (120), such that an annular seal member (144) circumferentially disposed around the lower portion is in sealing engagement with the inner surface of the cannula hub (122). In this way, the interior of the seal assembly (130) is in fluid communication with the lumen of the cannula (120) to define a working channel (114) of the cannula assembly (112) through which insufflation fluid, surgical instruments, and tissue fragments can be directed generally in the manner described above in relation to the trocar (10). The seal assembly (130) may be further configured in accordance with one or more teachings of U.S. Patent Application Publication No. 2019 / 0090905, published on March 28, 2019, entitled "Trocar Seal Assemblies", the disclosure of which is incorporated herein by reference, and / or U.S. Patent Application Publication No. 2019 / 0380742, published on December 19, 2019, entitled "Asymmetric Shaft Seal", the disclosure of which is incorporated herein by reference.

[0025] As best shown in FIG. 5, the obturator (116) of the trocar (110) includes a proximal head (150), an elongated cylindrical shaft (152) extending distally from the head (150), and a tapered distal tip (154) at the distal end of the shaft (152). The obturator head (150) includes a domed upper body (156), a base plate (158), and an operable latch member (160) including a pair of latch arms (162) and a corresponding pair of downwardly extending latch buttons (164). The latch arms (162) are configured to be captured within respective slots (138) formed in the upper surface of the upper frame member (132) of the seal assembly (130) to couple the obturator (116) to the cannula assembly (112). The latch buttons (164) are operable to release the latch arms (162) from the slots (138), thereby enabling separation of the obturator (116) from the cannula assembly (112).

[0026] The cannula (120) and obturator (116) of the present embodiment are preferably constructed of a robust material such as surgical steel, such that they can be sterilized and reused for a plurality of surgical procedures. In contrast, as described above, the seal assembly (130) is constructed as a disposable unit intended to be separated from the cannula (120) and replaced after each procedure. For example, the seal assembly (130) can be constructed of various polymeric materials including plastics and rubbers such that the seal assembly (130) can be easily manufactured and sold at a price suitable for disposing of the seal assembly (130) in the same manner as the trocar (10) described above.

[0027] II. Exemplary Balancing Features for a Reusable Trocar As best shown in FIG. 6, the center of gravity (CG1) of the cannula assembly (112) is located near the proximal end of the elongated cylindrical tube (124) and near the bell-shaped hub (122). Further, the cross-sectional thickness of the elongated cylindrical tube (124) can be substantially uniform at the proximal and distal ends of the elongated cylindrical tube (124) and can have a slight deviation in cross-sectional thickness to accommodate the annular rib (128). In other words, the inner and outer diameters of the proximal and distal portions of the cylindrical tube (124) can be substantially the same.

[0028] Since the cannula (120) and the obturator (116) are constructed from a robust material, the cannula (120) and the obturator (116) can have a greater mass and resulting weight compared to the cannula (12) and the obturator (16) of the single-use trocar (10) described above. As will be explained in more detail below, the greater mass and weight of the cannula (120) can cause instability and / or deficiency of the balance of the cannula (120) with respect to the abdominal wall (2) in the transverse (i.e., radial, or lateral) direction, whereby the cannula (120) can tilt or incline to the side, and thus the working channel (114) can become misaligned with the targeted surgical area (T) during exemplary use in accordance with the description herein.

[0029] FIG. 7A shows a cannula assembly (112) that provides suitable access to a patient's cavity (1) via a working channel (114) in accordance with the teachings herein. Therefore, prior to accessing the position shown in FIG. 7A, the obturator (116) and the cannula assembly (112) may be used in combination with each other such that the obturator tip (154) and the cannula tip (126) are biased distally through the layers of skin (3), fat (4), and fascia (5) to access the cavity (1). Once access is provided, the clinician may remove the obturator (116) in accordance with the description herein. Next, as shown in FIG. 7A, the clinician may position the cannula assembly (112) at a desired location relative to the patient such that the central axis (A1) is aligned with the targeted surgical area (T). Similar to the tissue engagement ribs (26) described above, tissue engagement ribs (128) provided on the cannula tube (124) grip the layers of tissue (3, 4, 5) of the abdominal wall (2), and thus provide a cannula assembly (112) having at least a minimum of stability axially and transversely relative to the abdominal wall (2).

[0030] During exemplary use, in accordance with the description herein, after the clinician releases the cannula assembly (112) to access the cavity (1) via the working channel (114), it may be desirable to maintain proper alignment with the targeted surgical area (T) of the central axis (A1). However, in some cases, as shown in FIGS. 7A and 7B, when the clinician releases the cannula assembly (112), the cannula assembly (112) may become unbalanced and "tilt", whereby the working channel (114) becomes misaligned with the targeted surgical area (T).

[0031] When the center of gravity (CG1) is laterally spaced from the portion of the tissue engagement rib (128) that engages the abdominal wall (2), a fulcrum force and consequently torque can occur. The fulcrum force created by the weight of the cannula assembly (112) and acting at the center of gravity (CG1) is imparted as torque on the portion of the rib (128) that engages the abdominal wall (2) and can become unduly large, whereby the cannula assembly (112) tilts, thereby displacing the position of the working channel (114) from the targeted surgical area (T). The cannula assembly (112) can be more prone to tilting compared to the cannula assembly (12) described above, due in part to the increased weight of the cannula assembly (112), which results in a greater fulcrum force acting on the center of gravity and thus creates a greater tilting torque around the portion of the cannula assembly (112) positioned within the abdominal wall (2). Therefore, the location of the center of gravity that was acceptable for the lightweight single-use cannula (20) may not be acceptable for the heavier cannula (120) formed from a robust material to facilitate sterilization and reuse for multiple surgical procedures.

[0032] As described above, the cannula assembly (112) can become unbalanced and "tilt", whereby the working channel (114) will undesirably shift out of alignment with the targeted surgical area (T). Therefore, it may be desirable for the cannula assembly (112) to have a balancing feature that can help promote a desirable arrangement of the cannula assembly (112) relative to the abdominal wall (2) such that (A) the working channel (114) can remain properly aligned with the targeted surgical area (T) during exemplary use in accordance with the description herein and (B) the cannula (120) can be formed of a robust material for sterilization and reuse purposes.

[0033] Figures 8-11 illustrate an exemplary cannula (220) that may be used in place of the cannula (120) described above. Figures 12A and 12B illustrate an exemplary use of a cannula assembly (212) formed from the cannula (220) and the seal housing (130). The cannula assembly (220) includes a bell-shaped hub (222) at its proximal end, and an elongate cylindrical tube (224) that extends distally from the hub (222) and terminates at an angled cannula tip (226), all of which define a working channel (214). The outer surface of the cannula tube (224) includes a plurality of tissue gripping features in the form of annular ribs (228) disposed axially along an inner portion of the cannula tube (224). The bell-shaped hub (222), the elongate cylindrical tube (224), the angled cannula tip (226), the working channel (214), and the annular ribs (228) may be substantially similar to the bell-shaped hub (122), the elongate cylindrical tube (124), the angled cannula tip (126), the working channel (114), and the annular ribs (128) described above, with differences detailed below.

[0034] The cannula (220) also includes a balancing feature (235) incorporated into the cannula tube (224). As described in more detail below, the balancing feature (235) is configured to inhibit tipping of the cannula assembly (212) when the clinician releases the cannula assembly (212), such that the working channel (214) may remain aligned with the targeted surgical area (T).

[0035] The balancing feature (235) includes a proximal thin section (230) having a relatively thin wall thickness, a distal thick section (232) having a relatively thick wall thickness, and a transition section (234) between the proximal and distal sections (230, 232). The proximal thin section (230) may extend from the bell-shaped hub (222) to the proximal portion of the elongate cylindrical tube (224), while the distal thick section (232) may extend along the distal portion of the elongate cylindrical tube (224).

[0036] The bell-shaped hub (222) includes a distal stem (225) sized to receive the proximal end of the elongated cylindrical tube (224). The bell-shaped hub (222) is fixed to the cylindrical tube (224) via a distal stem (225) via a coupling (236). As will be apparent to those skilled in the art in view of the teachings herein, any suitable coupling (236) may be used. For example, the coupling (236) may include welding, adhesives, interference fits, and the like.

[0037] As best shown in FIG. 9, the proximal thin section (230) may be sized to have a smaller wall thickness compared to the distal thick section (232). The reduced wall thickness of the proximal thin section (230) may allow the proximal portion of the cannula (220) to be formed of less material compared to the corresponding portion of the cannula (120) described above. Therefore, the weight of the proximal thin section (230) may be smaller compared to the corresponding portion of the cannula (120) described above.

[0038] In this example, the bell-shaped hub (222) and the portion of the cylindrical tube (224) that defines the proximal thin section (230) have similar wall thicknesses. However, this is merely optional. In some cases, the bell-shaped hub (222) may have a different wall thickness compared to the portion of the cylindrical tube (224) that defines the proximal thin section (230). In some cases, the tip of the bell-shaped hub (222) may be cut so that it is formed of less material. In some cases, the bell-shaped hub (222) may be entirely optional such that the seal housing (130) is configured to operably couple to the proximal end of the elongated tube (224) without the need for a complete bell-shaped hub (222).

[0039] The distal thick section (232) can be formed to have a greater wall thickness compared to the proximal thin section (230). The increased wall thickness of the distal thick section (232) can enable the distal portion of the cannula (220) to be formed of more material compared to the corresponding portion of the cannula (120) described above. Therefore, the weight of the distal thick section (232) can be greater compared to the corresponding portion of the cannula (120) described above.

[0040] The transition portion (234) is located between the proximal thin section (230) and the distal thick section (232). In this example, as shown in FIG. 10, the transition portion (234) is located immediately proximal to the proximal end of the annular rib (228). In this example, the transition portion (234) is located adjacent to the proximal end of the annular rib (228), and the transition portion (234) can be disposed at any suitable location as will be apparent to those skilled in the art in view of the teachings herein.

[0041] As also shown in FIG. 10, the wall thickness of the thinner section (230) defined by the tube (224) is determined by the distance between the inner surface (240) of the tube (224) and the proximal outer surface (242) of the tube (224). In this example, the distance between the surfaces (240, 242) is substantially uniform along the length of the proximal section (230). In other words, the inner diameter defined by the inner surface (240) and the outer diameter defined by the proximal outer surface (242) are substantially uniform along the length of the proximal section (230). However, this is merely optional. In some cases, the distance between the surfaces (240, 242) can vary along the length of the proximal section (230).

[0042] As best shown in FIG. 11, the wall thickness of the thicker section (232) is determined by the distance between the inner surface (240) of the tube (224) and either (A) the distal outer surface (244) of the tube (224) or (B) a portion of the annular rib (228). Each annular rib (228) is formed from a shoulder portion (250) and a tapered portion (252), and the shoulder portion (250) and the tapered portion (252) are connected at their outer edges. The distal outer surface (244) may not project laterally away from the working channel (214) farther than the shoulder portion (250) of the annular rib (228). This may help ensure that the annular rib (228) still appropriately grips tissue to promote the stability of the cannula (220) during exemplary use.

[0043] In this example, the distance between the surfaces (240, 244) is substantially uniform along the length of the tube (224) including the distal outer surface (244). In other words, the inner diameter defined by the inner surface (240) and the outer diameter defined by the distal outer surface (244) are substantially uniform along the length of the distal section (232) having the distal outer surface (244). However, this is merely optional. In some cases, the distance between the surfaces (240, 244) may vary along the length of the distal section (232).

[0044] In addition, in this example, the dimensions of the inner surface (240) are substantially uniform along the length of the tube (224). In other words, the inner diameter defined by the inner surface (240) is substantially uniform along the length of the tube (224). However, this is merely optional, as those skilled in the art will appreciate in view of the teachings herein, since the dimensions of the working channel (214) defined by the inner surface (240) may have any suitable geometric shape. For example, the inner surface (240) may have a tapered geometry, a corrugated geometry, etc.

[0045] The shift in weight distribution caused by the dimensional changes of the proximal thin section (230) and the distal thick section (232) can shift the center of gravity (CG2) of the cannula (220) distally compared to the center of gravity (CG1) of the cannula (120) described above. As will be explained in more detail below, this can enable the balancing feature (235) to prevent accidental tilting of the cannula assembly (220) during exemplary use.

[0046] FIG. 12A shows a cannula assembly (212) that provides suitable access to a patient's cavity (1) via a working channel (214) in accordance with the teachings of this specification. Therefore, prior to accessing the position shown in FIG. 12A, the obturator (116) and the cannula assembly (212) may be used in combination with each other such that the obturator tip (154) and the cannula tip (226) are biased distally through the layers of skin (3), fat (4), and fascia (5) to access the cavity (1). Once access is provided, the clinician may remove the obturator (116) in accordance with the description herein. Next, as shown in FIG. 12A, the clinician may position the cannula assembly (212) at a desired location relative to the patient such that the central axis (A2) is aligned with the targeted surgical area (T). Similar to the tissue engagement ribs (26) described above, tissue engagement ribs (228) provided on the cannula tube (224) grip the layers of tissue (3, 4, 5) of the abdominal wall (2) and thus provide a cannula assembly (212) having at least a minimum stability axially and transversely with respect to the abdominal wall (2).

[0047] During exemplary use, following the description herein, after the clinician releases the cannula assembly (212) to access the cavity (1) through the working channel (214), it may be desirable to maintain proper alignment of the central axis (A2) with the targeted surgical area (T). As shown in FIGS. 12A and 12B, when the clinician releases the cannula assembly (212), the equilibration feature (235) of the cannula (220) prevents the cannula assembly (212) from tilting, thereby allowing the working channel (214) to remain aligned with the targeted surgical area (T).

[0048] The placement of the center of gravity (CG2) closer to the portion of the elongate cylindrical tube (224) designed to engage the abdominal wall (2) can reduce the fulcrum forces and resulting torques imparted to the portion of the tissue engagement rib (228) that engages the abdominal wall (2) due to the weight of the cannula (220), as compared to the fulcrum forces and torques imparted by the center of gravity (CG1) of the cannula (120) described above. This reduction in fulcrum forces can result, at least in part, from a reduction in the lateral distance between the center of gravity (CG2) and the portion of the tissue engagement rib (228) that engages the abdominal wall (2). Therefore, shifting the center of gravity (CG2) closer to the portion of the tube (224) that engages the abdominal wall (2) can enable the clinician to more easily equilibriate the cannula (220) with respect to the patient's abdominal wall (2) and keep the working channel (214) aligned with the targeted surgical area (T).

[0049] In other words, although the total weight of the cannula (220) formed from a robust, sterilizable, and reusable material may not be able to be significantly reduced, the geometric shape of the cannula (220) can be modified so as to effectively shift the center of gravity (CG2) closer to the portion of the tube (224) configured to engage the abdominal wall (2), thereby reducing the fulcrum force applied to the engagement between the tube (224) of the cannula (220) and the patient's abdominal wall (2) and the resulting torque. Therefore, the modified center of gravity (CG2) can help reduce the chance that the cannula assembly (212) will tilt during use.

[0050] FIG. 13 shows another exemplary cannula (270) that can be used in place of the cannulas (120, 220) described above. The cannula (270) is substantially similar to the cannula (220) described above, except that the balancing feature (285) includes a large difference in mass and the resulting weight between the proximal thin section (280) and the distal thick section (282), whereby the center of gravity (CG3) is shifted further distally.

[0051] The cannula (270) includes a bell-shaped hub (272) at its proximal end and an elongate cylindrical tube (274) extending distally from the hub (272) and terminating in an angled cannula tip (276), all of which define a working channel (264). The outer surface of the cannula tube (274) includes a plurality of tissue gripping features in the form of annular ribs (278) disposed axially along the inner portion of the cannula tube (274). The bell-shaped hub (272), the elongate cylindrical tube (274), the angled cannula tip (276), the working channel (264), and the annular ribs (278) can be substantially similar to the bell-shaped hub (222), the elongate cylindrical tube (224), the angled cannula tip (226), the working channel (214), and the annular ribs (228) described above, with differences detailed below.

[0052] The balancing feature portion (285) includes a proximal thin section (280), a distal thick section (282), and a transition section (284), which may be substantially similar to the proximal thin section (230), distal thick section (232), and transition section (234) described above, and differences will be detailed herein. Therefore, the bell-shaped hub (272) is coupled to the tube (274) via a coupling (286), while the thickness of the thinner section (280) defined by the tube (274) is determined by the distance between the inner surface (290) of the tube (274) and the proximal outer surface (292) of the tube (274). Additionally, the wall thickness of the thicker section (282) is determined by the distance between the inner surface (290) of the tube (274) and either (A) the distal outer surface (294) of the tube (274) or (B) a portion of the annular rib (278).

[0053] As described above, the balancing feature portion (285) includes a significant difference in mass and resulting weight between the proximal thin section (280) and the distal thick section (282), whereby the center of gravity (CG3) is shifted further distally. In this example, this is achieved by having a larger distal thick section (282) in both length and wall thickness compared to the proximal thin section (280). Therefore, it should be understood that the geometric shape of the cannula (270) can be modified to adjust the center of gravity (CG3) to a desired location along the tube (274) in order to provide optimal balancing of the cannula (270) by minimizing the fulcrum forces and resulting torques applied to the portion of the tube (274) that engages the abdominal wall (3) due to the weight of the cannula (270).

[0054] The proximal thin sections (230, 280) and the distal thick sections (232, 282) can have any suitable dimensions, as will be apparent to those skilled in the art in view of the teachings herein. Additionally, the proximal thin sections (230, 280) and the distal thick sections (232, 282) can form any suitable wall thickness ratio, as will be apparent to those skilled in the art in view of the teachings herein. For example, the proximal thin sections (230, 280) can have a wall thickness of 0.020 inches, while the distal thick sections (232, 282) can have a wall thickness of 0.042 inches, resulting in a wall thickness ratio of 0.47619. As another example, the proximal thin sections (230, 280) can have a wall thickness of 0.010 inches, while the distal thick sections (232, 282) can have a wall thickness of 0.045 inches, resulting in a wall thickness ratio of 0.2222. Other suitable wall thickness ratios include, but are not limited to, 1:2, 1:4, 1:5, etc.

[0055] III. Exemplary Combinations The following examples relate to various non-exhaustive ways in which the teachings herein can be combined or applied. It should be understood that the following examples are not intended to limit the claims that may be presented at any time in this application or in a subsequent application of this application. No waiver of any rights is intended. The following examples are provided for illustrative purposes only. It is contemplated that the various teachings herein can be configured and applied in many other ways. Also, in some variations, it is contemplated that certain features mentioned in the following examples may be omitted. Accordingly, none of the aspects or features mentioned below should be considered important unless so explicitly indicated later by the inventors or their successors in interest. If the claims presented in this application or in a subsequent application related to this application include additional features other than those mentioned below, those additional features should not be considered to have been added for any reason related to patentability.

Example

[0056] A surgical access device assembly comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube. The cannula tube comprises: (i) tissue engagement features disposed along the outer surface of the cannula tube, the tissue engagement features being configured to stabilize the cannula tube and the cannula hub against the body cavity wall when the cannula tube is inserted distally through the body cavity wall of a patient; and (ii) balancing features configured to promote the lateral stability of the cannula tube and the cannula hub against the body cavity wall of the patient. The balancing features comprise: (A) a proximal portion of the cannula tube having a first wall thickness, at least a portion of the proximal portion being disposed proximal to the tissue engagement features; and (B) a distal portion of the cannula tube having a second wall thickness, the second wall thickness of the distal portion being greater than the first wall thickness of the proximal portion, at least a portion of the distal portion being disposed distal to the tissue engagement features.

Example

[0057] The surgical access device according to Example 1, wherein the cannula tube comprises an inner surface defining the working channel, the inner surface extending from the proximal portion to the distal portion and having a uniform inner diameter extending between the proximal portion and the distal portion.

Example

[0058] The surgical access device according to Example 1 or 2, wherein the balancing features comprise a transition portion located between the proximal portion and the distal portion, the transition portion coinciding with the proximal end of the tissue engagement features.

Example

[0059] The surgical access device according to any one or two or more of Examples 1 to 3, wherein the tissue engagement feature portion includes a tissue engagement rib having shoulder portions and tapered portions that are joined to each other at the outer edge.

Example

[0060] The surgical access device according to Example 4, wherein the proximal portion has a proximal outer surface, the distal portion has a distal outer surface, and the proximal outer surface is closer to the working channel as compared to the distal outer surface.

Example

[0061] The surgical access device according to Example 5, wherein the distal outer surface is closer to the working channel than the outer edge of the tissue engagement rib.

Example

[0062] The surgical access device according to any one or two or more of Examples 1 to 6, wherein the cannula hub includes a bell-shaped body sized to receive a disposable seal assembly.

Example

[0063] The surgical access device according to Example 7, wherein the cannula hub further includes a distal stem coupled to the proximal portion of the cannula tube.

Example

[0064] The surgical access device according to any one or two or more of Examples 1 to 8, wherein the surgical access device is formed from surgical steel.

Example

[0065] The surgical access device according to any one or two or more of Examples 1 to 9, wherein the cannula tube terminates within an angled cannula tip.

Example

[0066] The surgical access device according to any one or more of Examples 1 to 10, wherein the tissue engagement feature portion includes a plurality of tissue engagement ribs extending along a distal segment of the distal portion.

Example

[0067] The surgical access device according to Example 11, wherein the plurality of tissue engagement ribs terminate distally relative to the proximal portion of the cannula tube.

Example

[0068] The surgical access device according to any one or more of Examples 1 to 12, further comprising an obturator configured to be removably coupled to the cannula tube along a longitudinal axis to facilitate insertion of the surgical access device through the patient's body wall.

Example

[0069] The surgical access device according to any one or more of Examples 1 to 13, wherein the cannula hub is configured to selectively couple with a seal assembly.

Example

[0070] The surgical access device according to any one or more of Examples 1 to 14, wherein the proximal portion and the distal portion define a wall thickness ratio of 1:2.

Example

[0071] A surgical access device assembly comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, the cannula tube comprising: (i) a proximal portion of the cannula tube having a first wall thickness; (ii) tissue engagement features disposed along an outer surface of the cannula tube, the tissue engagement features being configured to stabilize the cannula tube and the cannula hub against a body cavity wall when the cannula tube is inserted distally through the body cavity wall of a patient; and (iii) a distal portion of the cannula tube having a second wall thickness, the tissue engagement features being interposed between the proximal portion and the distal portion, and the second wall thickness of the distal portion being greater than the first wall thickness of the proximal portion.

Example

[0072] The surgical access device according to Example 16, wherein the tissue engagement features include a plurality of tissue engagement ribs.

Example

[0073] The surgical access device according to Example 16, wherein a maximum wall thickness of the tissue engagement ribs is greater than the second wall thickness of the distal portion.

Example

[0074] The surgical access device according to any one or more of Examples 16 to 18, wherein the cannula hub comprises a bell-shaped body.

Example

[0075] A surgical access device assembly comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, the inner surface of the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, the cannula tube comprising: (i) a proximal portion of the cannula tube including a first wall thickness defined by an inner surface and a proximal outer surface; and (ii) a distal portion of the cannula tube including a second wall thickness defined by an inner surface and a distal outer surface, the distal portion terminating within an open distal end, the second wall thickness of the distal portion being greater than the first wall thickness of the proximal portion.

[0076] IV. Others It should be understood that any one or more of the teachings, expressions, embodiments, examples, etc. described herein can be combined with any one or more of the other teachings, expressions, embodiments, examples, etc. described herein. Therefore, the above teachings, expressions, embodiments, examples, etc. should not be considered in isolation from each other. Various suitable ways of combining the teachings of this specification will be readily apparent to those skilled in the art upon consideration of the teachings of this specification. Such modifications and variations are intended to be included within the scope of the claims.

[0077] Furthermore, any one or more of the teachings of this specification are incorporated herein by reference in their entirety from U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP1] (entitled "Pinch-To-Release Cannula Depth Limiter"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP2] (entitled "Multi-Diameter Cannula Depth Limiter"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP3] (entitled "Pinch-To-Clamp Cannula Depth Limiter"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP4] (entitled "Universal Size Multi-Walled Elastomer Cannula Depth Limiter"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP5] (entitled "Threaded Cannula Depth Limiter"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP6] (entitled "Tilting Tang Cannula Depth Limiter"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP7] (entitled "Two Piece Separable Obturator"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP8] (entitled "Latchless Obturator with Interference Fit Feature"), filed on the same date as this application; U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP10] (entitled "Airflow Channels and Patterns in Lumen for Cannula"), filed on the same date as this application; and / or U.S. Patent Application No. [Agent Docket No. REF NO END9247USNP11] (entitled "Stabilizer for Surgical Shafts orIt can be combined with any one or more of the teachings disclosed in (entitled "Cannulas"). The disclosure of each of these patent applications is incorporated herein by reference.

[0078] It should be understood that all or part of any patent, publication, or other disclosure referred to as being incorporated herein by reference is incorporated herein only to the extent that the incorporated content does not conflict with existing definitions, opinions, or other disclosure in this disclosure. By itself, and to the extent necessary, the disclosure clearly set forth herein shall supersede any conflicting description incorporated herein by reference. Any content, or portions thereof, referred to as being incorporated herein by reference but which conflict with the current definitions, opinions, or other disclosure set forth herein shall be incorporated only to the extent that no conflict arises between the incorporated content and the current disclosure.

[0079] The above-described variations of the device can be applied not only to conventional medical procedures and surgeries performed by medical professionals, but also to robot-assisted medical procedures and surgeries. As just one example, the various teachings herein can be readily incorporated into robotic surgical systems such as the DAVINCI (trademark) system by Intuitive Surgical, Inc. (Sunnyvale, California). Similarly, one of ordinary skill in the art will recognize that the various teachings herein can be readily combined with any of the following various teachings: U.S. Patent No. 5,792,135, entitled "Articulated Surgical Instrument For Performing Minimally Invasive Surgery With Enhanced Dexterity and Sensitivity," issued August 11, 1998, the disclosure of which is incorporated herein by reference; U.S. Patent No. 8,783,541, entitled "Robotically-Controlled Surgical End Effector System," issued July 22, 2014, the disclosure of which is incorporated herein by reference; U.S. Patent No. 8,479,969, entitled "Drive Interface for Operably Coupling a Manipulatable Surgical Tool to a Robot," issued July 9, 2013; U.S. Patent No. 8,800,838, entitled "Robotically-Controlled Cable-Based Surgical End Effectors," issued August 12, 2014 (the disclosure of which is incorporated herein by reference); and / or U.S. Patent No. 8,573,465, entitled "Robotically-Controlled Surgical End Effector System with Rotary Actuated Closure Systems," issued November 5, 2013 (the disclosure of which is incorporated herein by reference).

[0080] The variations of the above device can be designed to be disposed of after a single use, or they can be designed to be used multiple times. The variations can, in either or both cases, be reconditioned for reuse after at least one use. Reconditioning can include any combination of a device disassembly process, followed by a cleaning or replacement process of specific parts, and then a reassembly process. In particular, some variations of the device can be disassembled, and any number of specific parts or components of the device can be selectively replaced or removed in any combination. When cleaning and / or replacing specific parts, some variations of the device can be reassembled for subsequent use at a reconditioning facility or by the user immediately prior to treatment. One skilled in the art will understand that various techniques for disassembly, cleaning / replacement, and reassembly can be utilized in the reconditioning of the device. The use of such techniques, and the resulting reconditioned device, are all within the scope of this application.

[0081] Merely by way of example, the variations described herein may be sterilized before and / or after treatment. In one sterilization technique, the device is placed in a sealed and enclosed container such as a plastic or TYVEK bag. Next, the container and device may be placed in a radiation field that can penetrate the container, such as gamma rays, X-rays, or high-energy electron beams. The radiation may kill bacteria on the device and within the container. Next, the sterilized device may be stored in the sterilized container for later use. The device can also be sterilized using any other technique well known in the art, including but not limited to beta or gamma rays, ethylene oxide, or steam.

[0082] Although various embodiments of the present invention have been shown and described, further adaptations of the methods and systems described herein can be achieved by those skilled in the art with appropriate modifications without departing from the scope of the present invention. Some of such possible modifications have been described, but other modifications will be apparent to those skilled in the art. For example, the above-described examples, embodiments, geometric shapes, materials, dimensions, ratios, processes, etc. are illustrative and not essential. Therefore, the scope of the present invention should be considered with respect to the following claims and it is understood that it is not limited to the details of the structures and operations shown and described in this specification and the drawings.

[0083] 〔Embodiment〕 (1) A surgical access device assembly, (a) A cannula hub, and (b) A cannula tube extending distally from the cannula hub along a longitudinal axis, the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, the cannula tube comprising: (i) A tissue engagement feature disposed along an outer surface of the cannula tube, the tissue engagement feature being configured to stabilize the cannula tube and the cannula hub relative to the body cavity wall when the cannula tube is inserted distally through the body cavity wall of a patient; (ii) An equilibration feature configured to promote lateral stability of the cannula tube and the cannula hub relative to the body cavity wall of the patient, the equilibration feature comprising: (A) A proximal portion of the cannula tube having a first wall thickness, at least a portion of the proximal portion being disposed proximal to the tissue engagement feature; and (B) A distal portion of the cannula tube having a second wall thickness, wherein the second wall thickness of the distal portion is greater than the first wall thickness of the proximal portion, and at least a portion of the distal portion is disposed distally of the tissue engagement feature, the surgical access device assembly comprising a distal portion. (2) The cannula tube comprises an inner surface defining the working channel, the inner surface extending from the proximal portion to the distal portion, and the inner surface having a uniform inner diameter extending between the proximal portion and the distal portion, the surgical access device according to embodiment 1. (3) The balancing feature comprises a transition portion located between the proximal portion and the distal portion, the transition portion coinciding with the proximal end of the tissue engagement feature, the surgical access device according to embodiment 1. (4) The tissue engagement feature includes a tissue engagement rib having a shoulder portion and a tapered portion joined to each other at an outer edge, the surgical access device according to embodiment 1. (5) The proximal portion comprises a proximal outer surface, the distal portion comprises a distal outer surface, and the proximal outer surface is closer to the working channel compared to the distal outer surface, the surgical access device according to embodiment 4.

[0084] (6) The distal outer surface is closer to the working channel than the outer edge of the tissue engagement rib, the surgical access device according to embodiment 5. (7) The cannula hub comprises a bell-shaped body sized to receive a disposable seal assembly, the surgical access device according to embodiment 1. (8) The cannula hub further comprises a distal stem coupled to the proximal portion of the cannula tube, the surgical access device according to embodiment 7. (9) The surgical access device is formed from surgical steel, the surgical access device according to embodiment 1. (10) The cannula tube terminates within an angled cannula tip, the surgical access device according to embodiment 1.

[0085] (11) The surgical access device according to embodiment 1, wherein the tissue engagement feature portion includes a plurality of tissue engagement ribs extending along a segment of the distal portion. (12) The surgical access device according to embodiment 11, wherein the plurality of tissue engagement ribs terminate distally with respect to the proximal portion of the cannula tube. (13) The surgical access device according to embodiment 1, further comprising an obturator configured to be removably coupled to the cannula tube along the longitudinal axis to facilitate insertion of the surgical access device through the body wall of the patient. (14) The surgical access device according to embodiment 1, wherein the cannula hub is configured to selectively couple with a seal assembly. (15) The surgical access device according to embodiment 1, wherein the proximal portion and the distal portion define a wall thickness ratio of 1:2.

[0086] (16) A surgical access device assembly, comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, the cannula tube including: (i) a proximal portion of the cannula tube having a first wall thickness; and (ii) a tissue engagement feature disposed along an outer surface of the cannula tube, the tissue engagement feature being configured to stabilize the cannula tube and the cannula hub with respect to the body cavity wall when the cannula tube is inserted distally through the body cavity wall of the patient. (iii) The distal portion of the cannula tube having a second wall thickness, wherein the tissue engagement feature is interposed between the proximal portion and the distal portion, and the second wall thickness of the distal portion is greater than the first wall thickness of the proximal portion, a distal portion, comprising a surgical access device assembly. (17) The surgical access device according to embodiment 16, wherein the tissue engagement feature includes a plurality of tissue engagement ribs. (18) The surgical access device according to embodiment 16, wherein the maximum wall thickness of the tissue engagement rib is greater than the second wall thickness of the distal portion. (19) The surgical access device according to embodiment 16, wherein the cannula hub comprises a bell-shaped body. (20) A surgical access device assembly, comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, wherein an inner surface of the cannula tube defines a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, the cannula tube comprising: (i) a proximal portion of the cannula tube including a first wall thickness defined by the inner surface and a proximal outer surface; and (ii) a distal portion of the cannula tube including a second wall thickness defined by the inner surface and a distal outer surface, the distal portion terminating in an open distal end, and the second wall thickness of the distal portion being greater than the first wall thickness of the proximal portion, a distal portion, comprising a surgical access device assembly.

Claims

1. A surgical access device assembly comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, wherein the cannula tube comprises: (i) a tissue engagement feature disposed along an outer surface of the cannula tube, the tissue engagement feature being configured to stabilize the cannula tube and the cannula hub relative to a body cavity wall when the cannula tube is inserted distally through the body cavity wall of a patient; and (ii) a balancing feature configured to promote lateral stability of the cannula tube and the cannula hub relative to the body cavity wall of the patient, wherein the balancing feature comprises: (A) a proximal portion of the cannula tube having a first wall thickness, at least a portion of the proximal portion being disposed proximal to the tissue engagement feature; and (B) a distal portion of the cannula tube having a second wall thickness, the second wall thickness of the distal portion being greater than the first wall thickness of the proximal portion, at least a portion of the distal portion being disposed distal to the tissue engagement feature, wherein the tissue engagement feature comprises a tissue engagement rib comprising a shoulder portion and a tapered portion joined to each other at an outer edge.

2. A surgical access device assembly comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, wherein the cannula tube comprises: (i) a tissue engagement feature disposed along an outer surface of the cannula tube, the tissue engagement feature being configured to stabilize the cannula tube and the cannula hub relative to a body cavity wall when the cannula tube is inserted distally through the body cavity wall of a patient; (ii) a balancing feature configured to promote the lateral stability of the cannula tube and the cannula hub with respect to the body cavity wall of the patient, the balancing feature comprising: (A) a proximal portion of the cannula tube having a first wall thickness, at least a portion of the proximal portion being disposed proximal to the tissue engagement feature; and (B) a distal portion of the cannula tube having a second wall thickness, the second wall thickness of the distal portion being greater than the first wall thickness of the proximal portion, at least a portion of the distal portion being disposed distal to the tissue engagement feature, the tissue engagement feature including a plurality of tissue engagement ribs extending along a segment of the distal portion, a surgical access device assembly. **Claim 3** The cannula tube comprises an inner surface defining the working channel, the inner surface extending from the proximal portion to the distal portion, the inner surface having a uniform inner diameter extending between the proximal portion and the distal portion, the surgical access device assembly according to claim 1 or 2. **Claim 4** The balancing feature comprises a transition portion located between the proximal portion and the distal portion, the transition portion coinciding with the proximal end of the tissue engagement feature, the surgical access device assembly according to claim 1 or 2. **Claim 5** The proximal portion comprises a proximal outer surface, the distal portion comprises a distal outer surface, the proximal outer surface being closer to the working channel compared to the distal outer surface, the surgical access device assembly according to claim 1. **Claim 6** The distal outer surface is closer to the working channel than the outer edge of the tissue engagement rib, the surgical access device assembly according to claim 5. **Claim 7** The cannula hub comprises a bell-shaped body dimensioned to receive a disposable seal assembly, the surgical access device assembly according to claim 1 or 2. **Claim 8** The cannula hub further comprises a distal stem coupled to the proximal portion of the cannula tube, the surgical access device assembly according to claim 7. **Claim 9** The surgical access device assembly is formed from surgical steel, the surgical access device assembly according to claim 1 or 2. **Claim 10** The surgical access device assembly according to claim 1 or 2, wherein the cannula tube terminates within a angled cannula tip.

11. The surgical access device assembly according to claim 2, wherein the plurality of tissue engagement ribs terminate distally relative to the proximal portion of the cannula tube.

12. The surgical access device assembly according to claim 1 or 2, further comprising an obturator configured to removably couple with the cannula tube along the longitudinal axis to facilitate insertion of the surgical access device assembly through the body wall of a patient.

13. The surgical access device assembly according to claim 1 or 2, wherein the cannula hub is configured to selectively couple with a seal assembly.

14. The surgical access device assembly according to claim 1 or 2, wherein the proximal portion and the distal portion define a wall thickness ratio of 1:

2.

15. A surgical access device assembly, comprising: (a) a cannula hub; and (b) a cannula tube extending distally from the cannula hub along a longitudinal axis, the cannula tube defining a working channel configured to guide a surgical instrument along the longitudinal axis of the cannula tube, the cannula tube comprising: (i) a proximal portion of the cannula tube having a first wall thickness; (ii) a tissue engagement feature disposed along an outer surface of the cannula tube, the tissue engagement feature being configured to stabilize the cannula tube and the cannula hub relative to a body cavity wall when the cannula tube is inserted distally through the body cavity wall of a patient; and (iii) a distal portion of the cannula tube having a second wall thickness, the tissue engagement feature being interposed between the proximal portion and the distal portion, the second wall thickness of the distal portion being greater than the first wall thickness of the proximal portion. The surgical access device assembly, wherein the tissue engagement feature includes a tissue engagement rib having a shoulder portion and a tapered portion joined to each other at an outer edge.

16. The surgical access device assembly according to claim 15, wherein the tissue engagement feature portion includes a plurality of tissue engagement ribs.

17. The surgical access device assembly according to claim 16, wherein a maximum wall thickness of the plurality of tissue engagement ribs is greater than the second wall thickness of the distal portion.

18. The surgical access device assembly according to claim 15, wherein the cannula hub comprises a bell-shaped body.

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