Surgical Retractor Device

Abstract

The present invention relates to a surgical retractor device comprising a housing (7), a first press arm (2) pivotally connected to the housing, and a second press arm (3) pivotally connected to the housing, said first and second arms having rotational movement in a first plane, each press arm comprising a gripping member (4a, 4b) pivoting about an axis at the outer end of each press arm perpendicular to the first plane, and attachment means at the inner end of the arm, and the housing comprising an opening and closing mechanism. The housing (7) comprises an opening / closing mechanism (6) comprising first and second rotatable press arm mounting structures (10a, 10b) symmetrically spaced apart from a centerline of the surgical device for mounting the mounting means (5a, 5b) of the press arm to the housing (7), first and second rotatable handle mounting structures (13a, 13b) and a transmission mechanism for transmitting rotation from the first and second handle mounting structures (13a, 13b) to the first and second press arm mounting structures (10a, 10b). The device further comprises first and second handles (8, 9) for operating the opening / closing mechanism (6). The first and second handles (8, 9) comprise handle mounting means (14a, 14b) at inner ends of the handles for mounting the handles to the first and second handle mounting structures (13a, 13b), respectively, and a handle structure operable by a user. The first and second handles (8, 9) have rotational movement in a first plane and are symmetrically spaced apart from the centerline of the surgical device (1).

Description

[Technical Field]

[0001] The present invention relates to surgical retractor devices, and more particularly, the present invention relates to surgical retractor devices used in performing surgical exposures. [Background technology]

[0002] In the field of cardiothoracic surgery, such as sternotomy or thoracotomy, it is necessary to use self-retaining retractors to access the target anatomical region. Standard incisions in cardiothoracic surgery include sternotomy and thoracotomy. During thoracotomy procedures, retractors are used to spread the ribs and soft tissue, thereby allowing access to the pleural cavity. A complete or partial sternotomy is performed through a midline incision along the sternum, and the halves of the sternum are then separated by a sternal retractor to provide access to the heart and associated tissues. Retractors used in these procedures have jaws that open in a single plane. While any surgical exposure may provide sufficient access to the thoracic cavity, the procedure may place the patient under significant stress, and the extent and type of exposure must be weighed against morbidity. Consequently, these procedures are associated with significant postoperative pain and prolonged patient recovery times.

[0003] The force that the surgeon applies to the surgical incision through the device varies according to the angle of the hand lever in the Finochietto retractor design. The rotation speed of the hand lever is not linearly proportional to the arm opening speed, leaving the user without a sense of opening speed and force. One disadvantage of traditional retractors is the lack of force feedback, which makes it difficult for the surgeon to judge the amount of force to apply when accessing the anatomical site of interest. This means that the surgeon has a limited ability to know how much force to apply. It would be advantageous to precisely control the jaw opening so that the operator can avoid unnecessary damage to bone and tissue during retraction. Traditional retractors do not allow the operator to fine-tune and feel the force being exerted during retraction. The Finochietto retractor has moving metal-on-metal parts that require lubrication for optimal function; failure to lubricate the device after each sterilization will result in the device not functioning optimally. Additionally, the Finochietto retractor has a rotating lever on one side that moves transversely with the device as it rotates. Thus, the lever moves along the transverse plane of the surgical incision, which creates greater momentum for the device during operation due to the transverse deflection of the lever during retraction. When the Finochietto retractor is in the open position, the bar with the notches is exposed and can be awkwardly positioned. Primarily, the exposed notches can interfere with and damage surgical instruments, such as tubing and cords, and prevent the free movement of surgical instruments during surgery. A worst-case scenario is when the lever system straddles a crowded pacemaker cable, severing the fragile pacemaker cable.

[0004] Finally, following advances in the field of cardiothoracic surgery, additional types of surgical incisions are routinely performed. Traditional retractors have few interchangeable parts and do not always cater to the surgeon's particular preferences or patient needs.

[0005] Several other types of rib retractors have been developed to attempt to mitigate the disadvantages of the Finochietto retractor.

[0006] U.S. Patent No. 10,603,025 B2 discloses a surgical rib retractor having a housing with a first shoulder 70 and a second shoulder 74. The retractor further has first and second arm units 76, 78 pivotally coupled to the first and second shoulders. The surgical rib retractor further has first and second arm actuators 80, 82 for pivoting the first and second arms up and down. The surgical rib retractor of U.S. Patent No. 10,603,025 B2 further includes a rotatable knob 84 connected to a single actuator 84 for spreading the arms 76, 78 apart.

[0007] The disadvantages of the solution disclosed in US Patent No. 10,603,025 B2 are the same as those for the Finochietto retractor, mainly because the force is applied obliquely through the device by twisting the operating wheel and thereby applying a rotational moment. Moreover, the user must rotate the operating wheel the same number of times to close the retractor after surgery, which transmits uneven forces to the patient and delays closure of the device after the surgery is completed.

[0008] European Patent EP 2080480 A1 discloses a sternum retractor device comprising a pair of jaws 1a, 1b; 20a, 20b configured to be inserted between two sternum halves and shaped to tightly engage the halves, and an actuation means 2 comprising a hydraulic cylinder 3 and a piston 4 between the pair of jaws 1a, 1b; 20a, 20b. The hydraulic cylinder is actuated by a syringe. The device is not suitable for surgical exposure because the actuator and actuator arm obscure the surgical site. The use of a syringe to actuate the actuator does not provide the user with feedback regarding the force being applied to the patient. Furthermore, the member forcing the jaws apart includes hinges and sliding parts that could pinch and damage surgical equipment such as pacemaker wires and tubing.

[0009] Document WO2012040206A1 discloses a surgical retractor device including a first press arm 122 coupled to a pivotal holder assembly 104, a second press arm 126 coupled to the holder assembly 104, and a third press arm (316) slidably connected to the holder assembly 104. The solution disclosed in WO2012040206A1 exposes all mechanisms to the operation site, making disinfection difficult, exposing the surgical site to moving parts that may pinch and injure the patient, and exposing the surgical site to non-sterile equipment.

[0010] It is therefore an object of the present invention to provide a device that can be operated with one hand, where the force applied to operate the device is in the same plane as the opening of the arms, and where the applied force does not result in rotational movement of the device. It is also an object of the present invention to achieve a device that is easy to use, provides the user with the ability to fine-tune the device, requires little force to operate, can be closed in a rapid manner, and leaves the input lever in a stationary position.

[0011] It is a further object of the present invention to provide a device that can provide feedback to the user regarding the force being applied.

[0012] A further object of the present invention is to overcome the drawbacks of the known prior art.

[0013] To achieve these objects, a device according to the independent claims is provided. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] U.S. Patent No. 10603025B2 [Patent Document 2] European Patent EP2080480A1 [Patent Document 3] International Publication No. 2012040206A1 Summary of the Invention [Means for solving the problem]

[0015] The present invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention.

[0016] In a preferred embodiment of the present invention, the device includes a housing, a first press arm pivotally coupled to the housing, and a second press arm pivotally coupled to the housing, the first and second arms having rotational movement in a first plane. Each press arm includes a gripping member pivoting about an axis at an outer end of each press arm perpendicular to the first plane, and an attachment means at an inner end of the arm. The housing includes an opening / closing mechanism including first and second rotatable press arm attachment structures symmetrically spaced apart from a centerline of the surgical device for attaching the attachment means of the press arms to the housing, first and second rotatable handle attachment structures, and a transmission mechanism for transmitting rotation from the first and second handle attachment structures to the first and second press arm attachment structures. The device further comprises first and second handles for operating the opening and closing mechanism, each handle comprising handle attachment means at an inner end thereof for attaching said handle to first and second handle attachment structures, respectively, and a handle structure operable by a user, the first and second handles having rotational movement in a first plane and being symmetrically spaced apart from a centerline of the surgical device, the two handles being pretensioned in an open state, and opposite rotational movement of the first and second handles toward the centerline causing opposite rotational movement of the first and second press arms away from the centerline.

[0017] In another embodiment of the present invention, the transmission mechanism includes first and second cam arms, each cam arm coupled to a first and second handle mounting structure, first and second actuation arms, each actuation arm coupled to a first and second arm mounting structure, and a gear train including a reduction gear and / or a transmission gear coupled to a pinion gear, the pinion gear coupled to a worm gear. The gear train is rotatably coupled at one end to at least one of the first and second cam arms, and at the other end to at least one of the first and second actuation arms. The transmission mechanism is thereby adapted to convert rotational motion from at least one of the first and second cam arms to at least one of the first and second actuation arms.

[0018] In yet another embodiment of the invention, the transmission mechanism comprises first and second cam arms, each cam arm connected to a first and second handle mounting structure, respectively; first and second actuation arms, each actuation arm connected to a first and second press arm mounting structure, respectively; and at least a hydraulic actuator comprising a piston rod and a cylinder, the hydraulic actuator coupled at one end to at least one of the first and second cam arms and the hydraulic actuator coupled at the other end to at least one of the first and second actuation arms, whereby the transmission mechanism is adapted to translate rotational motion from the first and second cam arms to the first and second actuation arms.

[0019] In yet another embodiment of the invention, the transmission mechanism further comprises a further hydraulic actuator having a further piston rod and a further cylinder, the further hydraulic actuator coupled at one end to the second cam arm and at the other end to the second actuation arm, and the hydraulic actuator coupled at one end to the first cam arm and at the other end to the first actuation arm, whereby the transmission mechanism is adapted to translate rotational motion from the first and second cam arms to the first and second actuation arms, respectively.

[0020] In yet another embodiment of the invention, each of the first and second cam arms comprises a protruding surface area adapted to receive an end face of the piston rod and an at least partially toothed area comprising teeth or cogs, the at least partially toothed areas of the first and second cam arms intermeshing with each other to ensure synchronous rotation of the first and second handles in conjunction with each other.

[0021] In yet another embodiment of the invention, at least a spring pretensions the first and second handles in the open direction away from each other.

[0022] In yet another embodiment of the invention, the handle attachment means is removably attachable, and a surface of the handle attachment means is adapted to receive a corresponding surface of the handle attachment structure.

[0023] In yet another embodiment of the invention, the arm attachment means is removably attachable and a surface of the arm attachment means is adapted to receive a corresponding surface of the arm attachment structure.

[0024] In yet another embodiment of the invention, the opening and closing mechanism includes an open valve switch and an open valve fluidly coupled to the hydraulic actuator, whereby the open valve switch opens the valve to release pressure in the actuator, so that the first and second press arms are movable from an open state toward a closed state.

[0025] These and other characteristics of the invention will become apparent from the following description of preferred forms of embodiment given as non-limiting examples with reference to the accompanying schematic drawings. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 illustrates a surgical retractor device in a closed state. [Figure 2] FIG. 1 illustrates a surgical retractor device in an open state. [Figure 3] 1A-1C show a surgical retractor device with the inner workings of the housing exposed. [Figure 4] FIG. 1 is a close-up view of the housing exposing the inner workings of the housing. [Figure 5] A close-up view of the housing with the inner workings of the opening and closing mechanism. [Figure 6] A close-up view of the internal workings of the opening and closing mechanism. [Figure 7] A close-up view of the gear train of the opening and closing mechanism. [Figure 8] FIG. 1 illustrates a surgical retractor device with the handles in an open position. [Figure 9] 1A-1C illustrate a surgical retractor device in multiple states. DETAILED DESCRIPTION OF THE INVENTION

[0027] The following description uses terms such as "horizontal," "vertical," "lateral," "front-to-back," "upper," "lower," "inner," "outer," "forward," and "rearward." The central axis of the instrument is defined as extending horizontally along the central axis of the housing and the centerline between the press arms. The longitudinal direction is defined as the direction along the central axis. These terms generally refer to the views and orientations associated with standard usage of the present invention as seen in the drawings. The terms are used solely for the convenience of the reader and are not limiting. Similar numbers on different drawings describe the same features. Numbers with an apostrophe represent additional features represented by the same number; for example, the number 11 represents one or the first of a plurality or all of a plurality, and the number 11' represents additional or further features of the same feature, such as a second or multiple of the same feature.

[0028] FIG. 1 shows a surgical retractor device 1 in a closed state. The device comprises a watertight housing 7, a first press arm 2 pivotally coupled to the housing, and a second press arm 3 pivotally coupled to the housing, the first and second arms 2, 3 having rotational movement in a first plane. Each press arm comprises a gripping member 4a, 4b or jaw that pivots about an axis at the outer end of each press arm that is perpendicular to the first plane. The gripping members 4a, 4b are adapted to be inserted into a surgical incision. The pivoting of the gripping members 4a, 4b in conjunction with the first and second arms 2, 3 ensures that the arms 2, 3 are always parallel to the gripping side of the surgical incision when moved apart. The arms further comprise respective attachment means 5a, 5b at their inner ends for removably attaching the arms to the housing 7 or a part thereof. The gripping members 4a, 4b can be interchangeable with different shapes and sizes to meet different needs. While the gripping members 4a, 4b are shown as being relatively flat or square, they may also be elongated, curved, or deeper. The gripping members 4a, 4b may also have deeper or shallower gripping surfaces to provide a firmer grip on the surfaces being pulled apart.

[0029] The opening / closing mechanism 6 is located inside the housing. The housing must be watertight to facilitate sterilization and contain impurities such as oil, dust, and grease from the opening / closing mechanism. For the housing 7 to be watertight, the housing material may be watertight, and any openings or excess portions may be equipped with gaskets and / or seals to prevent the ingress or egress of any impurities or fluids. The housing may preferably be made of a structurally rigid material to withstand the applied force. The purpose of the mechanism 6 is to open and close the press arms 2 and 3 in a controllable, precise, and reliable manner. Figure 2 shows the device in an open state, and retraction of the press arms 2 and 3 exposes the surgical site. As shown in Figure 2, when the device is in the open position, the press arms 2 and 3 are curved toward the centerline of the device, i.e., each arm has a convex shape relative to the centerline, thus preserving the surgical space in the central area of ​​the chest or surgical site. Furthermore, all lubrication required for the device is limited to the interior of the housing 7 and any external sterilization of the device does not require lubrication of the opening and closing mechanism 6 .

[0030] The opening and closing mechanism must be activated manually or by an operator-controlled power source. The mechanism includes first and second rotatable press arm mounting structures 10a, 10b symmetrically spaced apart from the centerline of the surgical instrument for mounting the press arm mounting means 5a, 5b to the housing 7. The arm mounting means 5a, 5b may be removably attachable to the arm mounting structures for convenient sterilization and cleaning of the device. The arms 2, 3 may be replaced with arms 2, 3 of different lengths having different angles to meet different needs. The arms 2, 3 may also be angled in the first plane and in some relationship to the first plane. The surfaces of the arm mounting means 5a, 5b are adapted to receive corresponding surfaces of the arm mounting structures 10a, 10b in a manner that prevents relative rotation. The surface of the arm attachment means 5a, 5b may be a polygonal hollow or concave shape, and the surface of the arm attachment structure 10a, 10b may be a corresponding protruding or convex surface of said first shape, or vice versa, whereby the convex protrusions can fit into the holes or recesses but do not rotate relative to each other in the first plane. The attachment structures and attachment means of both the hand and arm may be provided with a locking mechanism, such as a safety pin or locking pin, to secure the attachment.

[0031] The opening / closing mechanism further includes first and second rotatable handle mounting structures 13a, 13b. The first and second handle mounting structures 13a, 13b protrude from the housing and are adapted to receive first and second handles 8, 9, respectively, for operating the opening / closing mechanism 6. The first and second handles 8, 9 include respective handle mounting means 14a, 14b at their inner ends for mounting the handles to the first and second handle mounting structures 13a, 13b, respectively. Surfaces of the handle mounting means 14a, 14b are adapted to receive corresponding surfaces of the handle mounting structures 13a, 13b in a manner that prevents relative rotation. The handle mounting means 13a, 13b may be removably attachable to the handle mounting structures for convenience in sterilizing and cleaning the device and for changing to differently shaped handles to meet user needs. The surfaces of the handle attachment means 14a, 14b may be polygonal, hollow, or concave, and the surfaces of the handle attachment structures 13a, 13b may be corresponding protruding or convex surfaces of the first shape, or vice versa, whereby the convex protrusions can fit into the holes or recesses but do not rotate relative to each other in the first plane. Each handle 8, 9 comprises a handle structure adapted for operation by a user with one hand. The attachment structures and attachment means of both the hand and arm may include a locking mechanism, such as a safety pin or locking pin, to secure the attachment. Furthermore, the handle attachment means (14a, 14b) may be removably attachable to the handle attachment structure.

[0032] When a user wishes to transition the device from a first, closed state to a second, open state in which the press arms 2, 3 are spread apart, the first and second handles are rotated toward each other, and the transmission mechanism transmits the rotation from the handles 8, 9 operated by the user to the first and second press arm mounting structures 10a, 10b via the first and second handle mounting structures 13a, 13b. To achieve this, the first and second handles 8, 9 have rotational motion in a first plane and are symmetrically spaced apart from the centerline of the surgical instrument. The two handles 8, 9 are pretensioned in the open direction, i.e., positioned relative to each other with at least a positive angle between them, and opposing rotational motion of the first and second handles 8, 9 toward the centerline causes opposing rotational motion of the first and second press arms 2, 3 away from the centerline. The opposing rotational movement of the first and second handles 8, 9 should be understood to be movement caused by squeezing or pressing the ends, i.e., outer ends, of the first and second handles 8, 9 that are not attached to the respective handle mounting structures 13a, 13b, toward each other. The two handles are pretensioned in the opening direction, thus creating a pumping action that is transferred to the controlled movement of the press arms 2, 3 by the opening / closing mechanism 6. Both handles move symmetrically about a centerline.

[0033] At least a spring 25 applies pretension to the first and second handles 8, 9, urging them apart in the open position. In Figures 4 and 5, the spring 25 is mounted in the housing 7 surrounding at least a portion of the longitudinally movable piston rod 16, urging the piston rod 16 toward the cam arms 15a, 15b and thereby spreading the first and second handles 8, 9. In an embodiment not shown, the spring 25 directly presses against the cam arms 15a, 15b; in other embodiments, the spring 25 directly presses against at least one of the first and second handle mounting structures 13a, 13b or at least one or part of the first and second handles 8, 9.

[0034] Because the force required to open the device 1 and retract the patient's ribs or sternum may be greater than the force generated by the hands in a single closing motion, the device, in an embodiment of the present invention, includes a transmission mechanism that transmits and multiplies the force input into the handles 8, 9 to the press arms 2, 3. This means that pressing the handles 8, 9 multiple times will force the arms to be pushed apart a certain distance with each press of the first and second handles 8, 9. As the force acting from the patient on the arms 2, 3 increases, the user will experience increasing resistance against the handles 8, 9, giving the user a tactile and palpable sense of the force being applied to the patient. The mechanism may be a mechanical gear and ratchet mechanism or a hydraulic mechanism.

[0035] FIG. 3 shows the device with its internal workings exposed. In FIG. 3, this embodiment of the present invention illustrates a transmission mechanism including first and second cam arms 15a, 15b. Each cam arm is coupled to a first and second handle mounting structure 13a, 13b, respectively. It should be understood that the first cam arm 15a is coupled to the first handle mounting structure 13a, and the second cam arm 15b is coupled to the second handle mounting structure 13b. The cam arms 15a, 15b are coupled to their respective handle mounting structures 13a, 13b in a fixed manner, i.e., a manner that does not allow relative rotation between the cam arms and their respective handle mounting structures, so that when the handle mounting structures 13a, 13b are rotated by one of the handles 8, 9, the cam arms also rotate. The transmission mechanism shown in FIG. 3 further includes first and second actuation arms 12a, 12b. Each actuation arm is connected to a first and second press arm mounting structure 10a, 10b, respectively. The first and second press arms 2 and 3 are pretensioned in the closed position, i.e., pressed together, by arm springs 26, 26' connected at least at one end to or part of the housing 7 and at the other end to or part of at least one of the arm mounting structures 10a, 10b.

[0036] In the illustrated embodiment of the present invention, the mechanism further comprises a hydraulic actuator 18 having a piston rod 16 and a cylinder 11. The hydraulic actuator 18 is coupled at one end to both the first and second cam arms 15a, 15b by being mounted against both the first and second cam arms 15a, 15b, and at the other end to both the first and second actuation arms 12a, 12b by being mounted against both the first and second actuation arms 12a, 12b. The transmission mechanism is thereby adapted to convert rotational motion from the first and second cam arms 15a, 15b to the first and second actuation arms 12a, 12b. Each actuation arm 12a, 12b is coupled to a first and second arm mounting structure 10a, 10b, respectively. This should be understood as meaning that the first actuation arm 12a is coupled to the first arm mounting structure 10a, and the second actuation arm 15b is coupled to the second arm mounting structure 10b. The actuation arms 12a, 12b are connected to their respective arm mounting structures 10a, 10b in a fixed rotational manner, i.e., in a manner that does not allow relative rotation between the actuation arms and their arm mounting structures, so that when the hydraulic actuator 18 extends and compresses the actuation arms 12a, 12b, it causes the actuation arms 12a, 12b to rotate about axes that pass through their respective mounting structures, which in turn rotate the rotatable arm mounting structures 10a, 10b, thereby spreading the press arms 2, 3.

[0037] FIG. 4 shows the device with the internal workings of the housing 7. In FIG. 4, an embodiment of the present invention illustrates a transmission mechanism comprising first and second hydraulic actuators 18, 18'. When multiple hydraulic actuators are disclosed, it should be understood that the hydraulic actuator 18 and one additional hydraulic actuator 18' are equivalent to at least the first hydraulic actuator 18 and the second hydraulic actuator 18'. In this embodiment, the actuator comprises a piston rod 16 and an additional cylinder 11, and the additional hydraulic actuator 18' comprises an additional piston rod 16' and an additional cylinder 11'. The additional hydraulic actuator 18' is coupled at one end to the second cam arm 15b and at the other end to the second actuation arm 12b. The hydraulic actuator 18 is coupled at one end to the first cam arm 15a and at the other end to the first actuation arm 12a. Thereby, when the handles 8, 9 are pressed together, the transmission mechanism is adapted to translate rotational motion from the first and second cam arms 15a, 15b to the first and second actuation arms 12a, 12b, respectively. In Figure 4, the first and second handles 8, 9 are shown in an open state and symmetrically spaced apart.

[0038] FIG. 5 shows a detailed view of the transmission mechanism. In the illustrated embodiment of the invention shown in FIG. 5, the transmission mechanism includes two hydraulic actuators 18, 18'. Each actuator includes a movable piston rod 16, 16', the piston rod having an end face mounted against at least one of the protruding surface areas 17, 17' of the cam arms 15a, 15b, respectively, and thus movably coupled to at least one of the surface areas 17, 17'. The opposite end of the piston rod 16, 16' includes a sealing portion that seals a hydraulic fluid volume defined by a piston chamber, which is in fluid communication with a check valve. The check valve is further fluidly coupled to a fluid volume 29, 29' defined by the primary cylinder 11, 11' and the sealing end portion of a primary cylinder rod 27, 27' within the primary cylinder 11, 11'. The primary cylinder 11, 11' is capable of translational movement in conjunction with the primary cylinder rod 27, 27'. In another embodiment not shown, the cylinder rods press against the handle mounting structures 13a, 13b and the main cylinders 11, 11' are stationary.

[0039] The user initiates opening of the press arms 2, 3 by pressing the first and second handles 8, 9 together, which are connected to the first and second handle mounting structures 13a, 13b, causing the first and second cam arms 15a, 15b to rotate, which in turn presses the piston rods 16, 16', causing translational movement of the rods and reducing the volume of hydraulic fluid in the piston chambers. At least a portion of the hydraulic fluid in the piston chambers is then forced through the check valves and into the volumes 29, 29' in the primary cylinders 11, 11'. This causes the cylinders 11, 11' and primary cylinder rods 27, 27' to extend relative to one another—as the volume of hydraulic fluid in the primary cylinders 11, 11' increases—and the primary cylinders 11, 11' are pushed away from the cylinder rods 27, 27' toward and away from the actuation arms 12a, 12b. This causes the arm mounting structures 10a, 10b to rotate, thereby opening the press arms 2, 3.

[0040] When the handles 8, 9 are released, the springs 25, 25' push the pistons 16, 16' in the opposite direction, causing translation of the piston rods 16, 16' against the cam arms 15a, 15b. This rotates the handles 8, 9, while simultaneously drawing hydraulic fluid from the fluid reservoir 28 through the second check valve into the increasing volume of the piston chamber. Further tightening of the handles 8, 9 results in another repetition of the above sequence, forcing the press arms 2, 3 to a greater width. By repeatedly tightening the handles 8, 9, the user can expand the press arms 2, 3 to the desired width. Symmetry along the centerline is maintained during use of the handles 8, 9. As the external force applied to the press arms, such as from a surgical wound or similar, increases, so does the force that must be applied by the user to the handles. This ensures that the user feels and assesses the force applied by the arms 2, 3 against the patient or object. In a non-illustrated embodiment of the invention, the device may include strain gauges and / or momentum meters and / or torque measuring devices to measure the force being applied to the arms 2, 3, i.e., the resistance from the body acting on the device. The device may further include a force or momentum indicator, either as a visual indicator with a scale or as an indicator that prevents the handles 8, 9 from being activated when a certain force on the arms 2, 3 is reached. This indication may be achieved by a torque wrench-type instrument, such as a deflection beam-type indicator, a slipper-type indicator, a click-type indicator, or an electronic device including a strain gauge. The indication may also indicate the pressure of the working fluid to indicate the achieved pressure of the press arms 2, 3.

[0041] The user's method for returning the device 1 to the closed state, i.e., closing the press arms 2, 3 together, involves the user activating the release valve switch 24. The release valve switch 24 is in communication with the release valve, which is fluidly coupled to the main cylinders 11, 11' and the reservoirs 28, 28'. When the release valve switch 24 is activated, the release valve fully opens, allowing hydraulic fluid to flow from the main cylinders 11, 11' into the fluid reservoirs 28, 28', restoring fluid pressure within the main cylinders 11, 11'. The pretensioned arm springs 26, 16' then pull the arms 2, 3 together, along with any external forces that may be acting on the arms 2, 3. In Figure 5, the first and second handles 8, 9 are shown symmetrically in the closed state. The release valve switch 24 and corresponding release valve ensure smooth and rapid closure of the arms 2, 3. The release valve switch 24 can be actuated to partially or fully close the arms 2, 3 either in a single fluid movement or in a step-wise closure, so that the user partially or fully closes the arms 2, 3 and, if adjustment is required, engages the handles 8, 9 to open the arms 2, 3. The instantaneous release of internal pressure in the main cylinders 11, 11' by actuation of the release valve results in a quick closure of the arms 2, 3, which can be beneficial when the device is used for surgery so that any surgical wound is not exposed longer than absolutely necessary.

[0042] In Figure 5, springs 26, 26' are connected at one end to housing 7 (not shown) or a part thereof and at the other end to at least one of arm mounting structures 10a, 10b via mounting means 30, 30' protruding from arm mounting structures 10a, 10b.

[0043] FIG. 3 illustrates an embodiment of the present invention using one hydraulic actuator 18. The transmission mechanism for this embodiment may have the same features as the previously disclosed embodiment shown in FIG. 5, except for the inclusion of one hydraulic actuator 18, and includes a movable piston rod 16 mounted against at least one of the protruding surface areas 17, 17′ of each of the cam arms 15a, 15b and thus having an end face movably coupled to at least one of the protruding surface areas 17, 17′. The opposite end of the piston rod 16 includes a sealing portion (not shown) that seals a working fluid volume defined by a piston chamber, which is in fluid contact with a check valve. The check valve is further fluidly coupled to a fluid volume defined by the primary cylinder 11 and a sealing end portion of a primary cylinder rod (not shown) within the primary cylinder 11. The primary cylinder 11 is capable of translational movement in conjunction with the primary cylinder rod 27.

[0044] FIG. 6 shows the internal workings of the housing 7 in an embodiment of the present invention, including a means for ensuring that the user rotates the first and second handles 8, 9 at the same speed and distance. This ensures that the press arms 2, 3 open at the same speed and the same distance from the centerline. A user may use either their left or right hand to operate the device, but the device does not favor one hand over the other, as if one handle were stationary relative to the other. To ensure that additional pressure is transferred from both hands to the press arms 2, 3 through the transmission mechanism, each of the first and second cam arms 15a, 15b includes at least a partially toothed area 23, 23' having teeth or cogs. The respective partially toothed areas 23, 23' protrude away from the handle mounting structures 13a, 13b, and the at least a partially toothed area 23, 23' of the first and second cam arms 15a, 15b interlock with each other to ensure synchronous rotation of the first and second handles 8, 9 in conjunction with each other.

[0045] 7 further shows that each of the first and second cam arms 15a, 15b includes a respective protruding surface area 17, 17' adapted to receive an end of a hydraulic actuator 18, 18'. In the illustrated example, the hydraulic actuators 18, 18' are mounted against the protruding surface areas 17, 17' of the cam arms 15a, 15b, respectively, and thus include an end surface on the piston rod 16, 16' adapted to be movably coupled to the protruding surface areas 17, 17'.

[0046] 7 shows a device with the internal workings of the housing 7 in an alternative embodiment of the invention, where the transmission mechanism comprises a gear train 19, said gear train 19 comprising a reduction gear and / or transmission gear 20 coupled to a pinion gear 21, said pinion gear being coupled to a worm gear 22. At one end, the gear train 19 is rotatably coupled to at least one of the first and second cam arms 15a, 15b via a toothed area 23, 23' on its periphery. At the other end, the gear train 19 is rotatably coupled to at least one of the first and second actuation arms 12a, 12b, at least one of the first and second actuation arms 12a, 12b comprising a toothed section corresponding to the worm gear screw. A transmission mechanism comprising a gear train 19 is adapted to translate rotational motion from at least one of the first and second cam arms 15a, 15b to at least one of the first and second actuation arms 12a, 12b. The handle mounting structure may include a pawl and ratchet mechanism (not shown) for repeated tightening of the handles to open the press arms 2, 3.

[0047] 8 shows the device 1 with the first and second handles 8, 9 in a fully open position, whereby the handles are either fully open or partially folded over or under the housing 7. In this way, when used for the purpose, the handles protrude minimally from the edges of the housing, but do not thereby interfere with or catch on any surgical instruments such as tubes and wires.

[0048] Figure 9 shows the device with the press arms 2, 3 in positions between open and closed, including fully closed, fully open, and partially open and closed. In Figure 8, a centerline CL is shown, but the arms 2, 3 are symmetrically positioned around the centerline in the open state, and the gripping members 4a, 4b meet at the centerline in the closed state.

[0049] Although not shown, the handle mounting structures 13a, 13b and arm mounting structures 10a, 10b, and thus the arms 2, 3 and handles 8, 9, may protrude from the housing 7 on the same side, either the upward or downward side of the housing, or on opposite sides, such that the arm mounting structures 10a, 10b protrude from the housing 7 on the upward side and the arm mounting structures 10a, 10b protrude from the housing 7 on the downward side, or vice versa. Both the arms 2, 3 and handles may be positioned so as not to impede the user's movement and not to interfere with tubes or cords used for other means. The arms 2, 3 and handles 8, 9 may also extend from side portions of the housing 7.

[0050] While particular embodiments of the present invention have been described and illustrated herein, it is recognized that modifications and variations will readily occur to those skilled in the art and, consequently, it is intended that the claims be interpreted to cover such modifications and equivalents. [Explanation of symbols]

[0051] 1 Surgical Retractor Instrument 2. First Press Arm 3 Second Press Arm 4a, 4b gripping members 5a, 5b Arm mounting means 6 Opening and closing mechanism 7. Housing 8 First Handle 9 Second Handle 10a, 10b Arm mounting structure 11, 11' Main cylinder 12a, 12b First and second actuation arms 13a, 13b Handle mounting structure 14a, 14b Handle attachment means 15a, 15b First and second cam arms 16, 16' Piston Rod 17, 17' Cam protruding surface area 18, 18' Hydraulic Actuator 19 Gear Train 20 gears 21 Pinion gear 22 Worm Gear 23, 23' Toothed area 24 Release valve switch 25 Lever spring 26 Arm spring 27, 27' Main cylinder rod 28, 28' Hydraulic fluid reservoir 29, 29' Limited fluid volume in the main cylinder 30, 30' spring mounting means

Claims

1. a housing (7); a first press arm (2) pivotally coupled to the housing; a second press arm (3) pivotally coupled to the housing, the first press arm and the second press arm (2, 3) having a rotational movement in a first plane; A surgical retractor device (1) comprising: - each press arm: - gripping members (4a, 4b) pivoting about axes at the outer ends of each press arm and perpendicular to said first plane; - attachment means (5a, 5b) at the inner ends of said arms, - said housing (7) An opening and closing mechanism (6) is provided, - first and second rotatable press arm mounting structures (10a, 10b), spaced symmetrically from the centerline of the surgical retractor device, for mounting the mounting means (5a, 5b) of the press arms to the housing (7); - first and second rotatable handle mounting structures (13a, 13b); a transmission mechanism for transmitting rotation from said first and second handle mounting structures (13a, 13b) to said first and second press arm mounting structures (10a, 10b), The surgical retractor device further comprises first and second handles (8, 9) for operating the opening and closing mechanism (6), each handle comprising: - handle attachment means (14a, 14b) at the inner end of said handle for attaching said handle to said first and second handle attachment structures (13a, 13b), respectively; a handle structure operable by a user; - said first and second handles (8, 9) have a rotational movement in said first plane and are spaced symmetrically from said centerline of the surgical retractor device (1); - the two handles (8, 9) are pretensioned in the open direction, a surgical retractor device (1), wherein opposing rotational movements of said first and second handles (8, 9) towards said centre line cause opposing rotational movements of said first and second press arms (2, 3) away from said centre line;

2. The transmission mechanism is - first and second cam arms (15a, 15b), each cam arm being connected to said first and second handle mounting structures (13a, 13b), respectively; - first and second actuation arms (12a, 12b), each actuation arm being connected to said first and second press arm mounting structures (10a, 10b), respectively; a gear train (19) comprising a reduction gear and / or a transmission gear (20) connected to a pinion gear (21), said pinion gear being connected to a worm gear (22); the gear train is rotatably coupled at one end to at least one of the first and second cam arms (15a, 15b); the gear train (19) is rotatably coupled at its other end to at least one of the first and second actuation arms (12a, 12b); 2. The device of claim 1, whereby the transmission mechanism is adapted to translate rotational motion from at least one of the first and second cam arms (15a, 15b) to at least one of the first and second actuation arms (12a, 12b).

3. The transmission mechanism is - first and second cam arms (15a, 15b), each cam arm being connected to said first and second handle mounting structures (13a, 13b), respectively; - first and second actuation arms (12a, 12b), each actuation arm being connected to said first and second press arm mounting structures (10a, 10b), respectively; - at least a hydraulic actuator (18) comprising a piston rod (16) and a cylinder (11); the hydraulic actuator (18) is coupled at one end to at least one of the first and second cam arms (15a, 15b); a hydraulic actuator (18) coupled at the other end to at least one of the first and second actuation arms (12a, 12b); 2. The device of claim 1, whereby the transmission mechanism is adapted to translate rotational motion from the first and second cam arms (15a, 15b) to the first and second actuation arms (12a, 12b).

4. The transmission mechanism is - further comprising a further hydraulic actuator (18') with a further piston rod (16') and a further cylinder (11'), said further hydraulic actuator (18') is coupled at one end to said second cam arm (15b) and at the other end to said second actuation arm (12b); the hydraulic actuator (18) is coupled at one end to the first cam arm (15a) and at the other end to the first actuation arm (12a); 4. The device of claim 3, whereby the transmission mechanism is adapted to translate rotational motion from the first and second cam arms (15a, 15b) to the first and second actuation arms (12a, 12b), respectively.

5. Each of the first and second cam arms (15a, 15b) - a projecting surface area (17, 17') adapted to receive the end face of said piston rod (16, 16'); - at least partially toothed areas (23, 23') with teeth or cogs, 5. A device according to claim 3 or 4, wherein the at least partially toothed areas (23, 23') of the first and second cam arms (15a, 15b) intermesh with each other to ensure synchronous rotation of the first and second handles (8, 9) in conjunction with each other.

6. 6. A device according to any one of claims 1 to 5, wherein at least a spring (25) pretensions the first and second handles (8, 9) in the direction of the open position away from each other.

7. 7. A device according to any one of claims 1 to 6, wherein the first and second handle attachment means (14a, 14b) are removably attachable, and surfaces of the handle attachment means (14a, 14b) are adapted to receive corresponding surfaces of the first and second handle attachment structures (13a, 13b).

8. A device as described in any one of claims 1 to 7, wherein the mounting means (5a, 5b) of the press arm are removably mountable and surfaces of the mounting means (5a, 5b) of the press arm are adapted to receive corresponding surfaces of the first and second press arm mounting structures (10a, 10b).

9. 5. The device according to claim 3, wherein the opening and closing mechanism (6) comprises an open valve switch (24) and an open valve fluidly coupled to the hydraulic actuator, whereby the open valve switch (24) opens the open valve to release pressure in the hydraulic actuator (18, 18′), thereby allowing the first and second press arms (2, 3) to move from an open state toward a closed state.

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