Device for a medical instrument for applying a surgical suture

Abstract

The invention relates to a device for a medical instrument for applying a surgical suture, comprising a base unit (1) to which two jaws (2a, 2b) are pivotably attached, each jaw having at least one needle holder which can be switched between a locking position and a release position in order to releasably hold a needle (3). Provided in the base unit (1) is a hydraulic cylinder (5) with a front piston (6) which is connected to a transmission mechanism which actuates a switching element which switches the needle holder between the locking position and the release position. A rear piston (7) controls the movement of the jaws (2a, 2b).

Description

[0001] Device for a medical instrument for applying a surgical suture

[0002] The invention relates to a device for a medical instrument for applying a surgical suture, with a base unit to which two jaws are pivotably attached, each having at least one needle holder to hold a needle releasably.

[0003] Many surgical procedures require the placement of a surgical suture. Thanks to innovative instruments, surgical methods have improved to such an extent that numerous procedures can now be performed endoscopically, thus minimizing the burden on the patient. EP 2 083 727 Bl describes a device of the type mentioned above, in which a forceps-like end effector is configured to place a surgical suture. Similar devices are also described in EP 2 462 877 A2.

[0004] EP 3 376 966 A describes a solution in which a mechanical device alternately opens and closes the needle holders, thus transferring a needle from one needle holder to the opposite needle holder each time the jaws close. While this device functions well in principle, the mechanism is complex and malfunctions can occur if the closing mechanism switches incorrectly.

[0005] US Patent 5,814,054 A discloses a medical device in which a needle is alternately transferred back and forth between two jaws. The necessary locking and unlocking of the needle holders is actuated by a switching mechanism. This solution also has a complex mechanism, and malfunctions can occur if the mechanism switches incorrectly.

[0006] It is an object of the invention to further develop the known devices and in particular to provide a device that has a simple design and is insensitive to operating errors.

[0007] This problem is solved according to the invention by the device mentioned at the outset in that a hydraulic cylinder with a front piston is provided in the base unit, which is connected to a transmission mechanism that actuates a switching element that switches the needle holder between the locking position and the release position, and that a rear piston controls the movement of the jaws.

[0008] Hydraulic actuation, instead of a mechanical solution, allows for safe and efficient power transmission even at sharp angles, while also enabling precise and sensitive control by a single operator. As with similar medical devices, a water-glycol mixture is used as the hydraulic fluid.

[0009] A particular advantage of the hydraulic solution compared to the known devices with clockwork-like needle transfer mechanisms is that it is impossible for the clockwork to skip a tooth and enter a non-functional position due to excessive force application or blockage.

[0010] A key feature of the present invention is that a suture with multiple stitches can be performed without having to remove the device from the patient's body, which is the case with known devices that use staples.

[0011] The device is preferably designed such that the needle is fixed in the locking position without any external holding force. This ensures that the needle cannot be lost even if the hydraulic system fails.

[0012] Preferably, the transmission mechanism comprises a slide in each jaw, which is particularly preferably movable in the longitudinal direction of the jaw and has a switching element at one end. This allows for efficient and reliable power transmission from the hydraulic cylinder to the needle holder. To optimally accommodate the movement of the jaws, it has proven advantageous for the slides to be moved via a driver that engages with counterparts on the slides when the jaws are closed. This has the additional advantage that adjustment of the slides when the jaws are open is prevented even in the event of operator error, since the driver and the counterparts are not engaged when the jaws are open.

[0013] A particularly compact solution is achieved by providing a front piston and a rear piston in the hydraulic cylinder, arranged one behind the other in the axial direction. The hydraulic cylinder is preferably divided into a front cylinder chamber and a rear cylinder chamber by a partition. It is particularly advantageous from a design perspective if the front piston is connected to an outer piston rod and the rear piston to an inner piston rod.

[0014] To ensure sufficient jaw closing force, the rear piston is connected via a piston rod to a drive head that controls the jaw movement. For example, pins on the drive head exert a force on arms that support the jaws, causing them to pivot. It is particularly advantageous if the pins are guided in elongated holes in the arms.

[0015] A particularly advantageous embodiment of the invention provides that the switching element arranged on the sliders consists of a keyhole-shaped recess through which the needle can be guided.

[0016] A particularly compact solution is achieved by providing grooves on the outside of the hydraulic cylinder to guide the hydraulic medium.

[0017] The invention is explained in more detail below with reference to a non-restrictive embodiment and the accompanying figures. These figures show:

[0018] • Fig. 1 and Fig. 2 show the device according to the invention in two different positions, each in an oblique longitudinal section;

[0019] • Fig. 3 shows the device in an oblique front view with the base unit omitted;

[0020] • Fig. 4 shows another oblique sectioned view of a detail in a half-open state;

[0021] • Figs. 5 to 8 show side views without the housing from four different directions;

[0022] • Figs. 9 and 10 show the two slides; and

[0023] • Fig. 11 shows a side view of the pistons and jaws.

[0024] The device according to the invention has a base unit 1 to which two jaws 2a, 2b are movably hinged in the manner of pliers. A needle 3 is provided at the front end of the jaws 2a, 2b, which is selectively held by one of the two jaws 2a, 2b in order to apply a surgical suture. In the closed state, the base unit 1 and the two jaws 2a, 2b are arranged in the form of a thin cylinder in order to allow the device to be easily inserted into a body orifice, such as through the mouth into the esophagus to apply a suture in the stomach.

[0025] The basic unit 1 consists of a housing 4 in which a hydraulic cylinder 5 is arranged, in which two pistons 6, 7 are axially arranged one behind the other and are independently movable. The front piston 6 controls the movement of the jaws 2a, 2b and the rear piston 7 controls the transfer of the needle 3 by means of a transmission mechanism.

[0026] Figures 1 and 2 show that the rear piston 7 controls an inner piston rod 8, at the front end of which a driver 9 is attached. When the jaws 2a, 2b are closed, the driver 9 engages in two counterparts 10a, 10b, which are slidable along the longitudinal direction of the jaws 2a, 2b. Each of the counterparts 10a, 10b is rigidly connected to a sliding slide 11a, 11b, which is shown separately in Figures 9 and 10. Each slide 11a, 11b has a keyhole-shaped recess 12a, 12b at its front end through which the needle 3 can pass. Depending on the position of the slides 11a, 11b, the needle 3 is either held in place or released. The keyhole-shaped recesses 12a, 12b are oriented in reverse, so that when the sliders 11a, 11b are in the forward-pushed position (Fig.l), the needle 3 is held by the upper slide 11a and released by the lower slide 11b, while in the rearward pushed position it is the other way around.

[0027] Each of the jaws 2a, 2b is pivotally connected to a retaining projection 16a, 16b at the front end of the base unit 1 via two arms 13a, 14a and 13b, 14b respectively, about an axis 15a, 15b. For clarity, arms 13a and 13b have been omitted in Figures 1 to 4.

[0028] The jaws 2a, 2b are opened by pushing the front piston 6 back from its forward position (Figs. 1 and 2). A drive head 18 is arranged on an outer piston rod 17, which is rigidly connected to the front piston 6. This drive head carries two pins 19 laterally. Each of the pins 19 engages in two oblique elongated holes in the arms 13a, 14a and 13b, 14b, respectively, as can be seen in Figs. 5 to 8. In the rear position of the front piston 6, the jaws 2a, 2b are maximally open.

[0029] Figures 1 and 2 show various seals 20 that are required for proper functioning.

[0030] The hydraulic actuation of the pistons 6 and 7 is effected via hydraulic connections 21, hydraulic lines 22 in the hydraulic cylinder 5, and grooves 23 on the outside of the hydraulic cylinder 5, in order to fill or empty the cylinder chamber through bores 24 in the wall of the hydraulic cylinder 5. The grooves 23 are sealed by the housing 4. Figures 5 to 8 show an example of the course of the grooves 23.

[0031] The hydraulic connections 21 are used to connect flexible hydraulic lines (not shown), which are supplied via a control unit. This control unit (not shown) applies pressure to the hydraulic lines according to the user's desired function in order to move the pistons 6, 7, which control the movement of the jaws 2a, 2b and the transfer of the needle 3. The control unit is also programmed to ensure that the rear piston 7 can only move when the jaws 2a, 2b are closed, so that the needle transfer can only occur under these conditions. Furthermore, when the jaws 2a, 2b are open, the driver 9 cannot be moved to a position that would block the closing of the jaws 2a, 2b.

[0032] The inner piston rod 8 is tubular and has a lumen 37 through which, for example, a tissue retractor (not shown here) can be inserted. The interior of the hydraulic cylinder 5 is divided by a fixed partition 25 into a front cylinder chamber 26 and a rear cylinder chamber 27 in order to control the two pistons 6 and 7 independently of each other.

[0033] Figures 9 and 10 show the slides 11a, 11b in detail. At the front end of each slide, a keyhole-shaped recess 12a, 12b is visible, consisting of a circular section 28 with an adjoining slot 29. The circular section 28 has a diameter larger than that of the needle 3 to allow it to pass through unimpeded. The slot 29, on the other hand, is adapted to grooves 30 in the needle 3 to hold it securely without the application of external force when the keyhole-shaped recess 12a, 12b is in the holding position. The ends of the needle 3 are received with play in receiving bores 36 in the jaws 2a, 2b.

[0034] At their opposite, rear ends, the slides 11a, 11b each have a rectangular recess 31 in which the counterparts 10a, 10b are attached. Laterally, the slides 11a, 11b have tongues 32 formed by corresponding recesses 33. At the end of each tongue 32, a projection 34 is arranged, which projects laterally beyond the contour of the slides 11a, 11b. The projections 34 are designed to engage resiliently in corresponding recesses 35 in the jaws 2a, 2b when these are in the open or closed end position. This is particularly important for the closed end position to ensure that the needle transfer takes place reliably with the jaws 2a, 2b fully closed, to prevent unintentional opening of the jaws 2a, 2b during the needle transfer, and to ensure that the device remains closed in the event of a hydraulic system failure.

[0035] The intended use of the device according to the invention will then be explained briefly and by way of example.

[0036] The device is attached to the front end of a flexible endosurgical instrument. It is inserted into the stomach via the patient's esophagus and, by means of a corresponding bend, is guided to the section of the stomach wall where a procedure is to be performed. The previously closed jaws 2a, 2b are then opened by applying pressure to the hydraulic cylinder 5.

[0037] A tissue retractor, inserted into lumen 37, is then inserted into the stomach wall in a corkscrew-like fashion and subsequently withdrawn to form a tissue fold that lies between the opened jaws 2a, 2b. The jaws 2a, 2b are then closed, allowing needle 3 to penetrate the tissue fold. While closed, the rear piston 7 is switched, thereby transferring needle 3 from one jaw 2a, 2b to the other. The jaws 2a, 2b are then opened again, and a thread (not shown) fixed in needle 3 is pulled through the tissue fold. This process can be repeated until the suture is complete.

[0038] The cylinder chambers of the hydraulic cylinder 5, namely the front cylinder chamber 26 and the rear cylinder chamber 27, are controlled via bores 24 extending from the grooves 23. Front bores 24 are provided for each cylinder, initiating movement of the respective piston 6, 7 in a proximal direction, and rear bores 24 for initiating movement of the respective piston 6, 7 in a distal direction. In addition, central bores 24 are provided for each cylinder, which are connected to vent lines via grooves 23 and are not required during normal operation. However, they facilitate the filling of the device's hydraulic system by allowing the air initially present in the cylinder chambers 26, 27 to be expelled.

[0039] 1 base unit;

[0040] 2a, 2b Baking; 3 Needle;

[0041] 4 Housing; 5 Hydraulic cylinder; 6 Front piston; 7 Rear piston; 8 Inner piston rod; 9 Drive pin;

[0042] 10a, 10b counterpart; 11a, 11b slide; 12a, 12b keyhole-shaped recess; 13a, 13b arms; 14a, 14b arms; 15a, 15b axle; 16a, 16b retaining projection; 17 outer piston rod; 18 drive head; 19 pins; 20 seals; 21 hydraulic connections; 22 hydraulic lines; 23 grooves; 24 bores; 25 partition; 26 front cylinder chamber; 27 rear cylinder chamber; 28 circular section; 29 slot; 30 grooves; 31 rectangular recesses; 32 tongues; 33 clearances; 34 projection; 35 recesses; 36 receiving bores; 37 lumen; 38 pinhole.

Claims

PATENT CLAIMS 1. Device for a medical instrument for applying a surgical suture, comprising a base unit (1) to which two jaws (2a, 2b) are pivotably attached, each having at least one needle holder which is switchable between a locking position and a release position in order to hold a needle (3) releasably, characterized in that a hydraulic cylinder (5) with a front piston (6) is provided in the base unit (1) which is connected to a transmission mechanism which actuates a switching element which switches the needle holder between the locking position and the release position, and that a rear piston (7) controls the movement of the jaws (2a, 2b).

2. Device according to claim 1, characterized in that the needle (3) is fixed in the locking position without an external holding force.

3. Device according to one of claims 1 or 2, characterized in that the transmission mechanism comprises a slide (11a, 11b) in each jaw (2a, 2b).

4. Device according to claim 3, characterized in that the slides (11a, 11b) are movable in the longitudinal direction of the respective jaw (2a, 2b) and have a switching element at one end.

5. Device according to one of claims 3 or 4, characterized in that the slides (11a, 11b) are moved via a driver (9) which, in a closed position of the jaws (2a, 2b), engages in counterparts (10a, 10b) on the respective slides (11a, 11b).

6. Device according to one of claims 1 to 5, characterized in that the front piston (6) and the rear piston (7) are provided one after the other in the hydraulic cylinder (5) in the axial direction.

7. Device according to claim 6, characterized in that the hydraulic cylinder (5) is divided by a partition (25) into a front cylinder chamber (26) and a rear cylinder chamber (27).

8. Device according to one of claims 6 or 7, characterized in that the front piston (6) is connected to an outer piston rod (17) and the rear piston (7) is connected to an inner piston rod (8).

9. Device according to one of claims 1 to 8, characterized in that the rear piston (7) is connected via a piston rod (8) to a drive head (18) which controls the movement of the jaws (2a, 2b).

10. Device according to one of claims 3 to 9, characterized in that the switching element arranged on the slides (11a, 11b) consists of a keyhole-shaped recess (12a, 12b) through which the needle (3) can be guided.

11. Device according to one of claims 1 to 10, characterized in that grooves (23) for guiding the hydraulic medium are provided on the outside of the hydraulic cylinder (5).

12. Device according to claim 11, characterized in that cylinder chambers (26, 27) of the hydraulic cylinder (5) are connected to the grooves (23) by bores (36).

13. Device according to claim 12, characterized in that the cylinder chambers (26, 27) of the hydraulic cylinder (5) are each connected to the grooves (23) by front, middle and rear bores (36).

14. Device according to claim 13, characterized in that the middle bores (36) are designed as vent bores.

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