WO2025146363A1

WO2025146363A1 - Surgical distractor

Info

Publication number: WO2025146363A1
Application number: PCT/EP2024/087455
Authority: WO
Inventors: Heiko Koller; Daniel Fluri; Silas Zurschmiede
Original assignee: 41medical AG
Current assignee: 41medical AG
Priority date: 2024-01-05
Filing date: 2024-12-19
Publication date: 2025-07-10
Anticipated expiration: 2026-07-05

Abstract

The present application relates to a surgical distractor (1) suitable for temporary distraction of two adjacent vertebral bodies of a patient's spine during a surgical procedure. The surgical distractor (1) comprises a guide rod (2) extending in a first direction (x) and a first pin (3) and a second pin (4) during operation interconnected to the guide rod (2) by a first joint (5) and a second joint (6) linearly displaceable with respect to each other, and at least one locking mechanism (7) which provides a locked position in which the first and the second pin (3, 4) are arranged non-tiltable with respect to each other, and an unlocked position, in which the first pin (3) and the second pin (4) are arranged tiltable with respect to each other.

Description

Surgical Distractor

FIELD OF THE DISCLOSURE

The present disclosure relates to a surgical distractor for temporary distraction of two adjacent vertebral bodies of a patient’s spine during a surgical procedure.

BACKGROUND OF THE DISCLOSURE

WO20221 25692A1 was published in June 2022 on behalf of Alphatec Spine Inc. It relates to a retractor assembly that includes a base portion in slidable engagement with two or more retractor arms with at least one of the retractor arms re- leasably securing a retractor blade configured to be anchored to a bone anchor. The retractor blade includes an elongate blade portion with a retractor engagement portion positioned at the proximal end of the elongate blade portion and an anchor mechanism positioned at the distal end of the elongate blade portion. The anchor mechanism includes a first jaw and second jaw configured to engage the bone implant. When closed around or anchored to the bone implant-which may be a shank of a modular screw system-the components of the modular screw are able to be assembled to the shank without adjusting, loosening, or opening the anchor mechanism.

US2018085105A1 was first published in March 2018 on behalf of K2M Inc. It relates to a method of distracting adjacent vertebral bodies. The method includes inserting a first pin into a first vertebral body and inserting a second pin into a second vertebral body adjacent the first vertebral body, thereafter positioning a first retractor blade over the first pin, positioning a second retractor blade over the second pin, attaching a first arm of a frame to the first retractor blade and a second arm of the frame to the second retractor blade, displacing the second arm of the frame away from the first arm to distract the first and second vertebral bodies, inserting prongs of a lateral protector into respective channels defined in the first and second retractor blades, and retracting tissue by a transverse blade of the lateral protector.

WO2015116624A1 was published in December 2016 on behalf of Spinal USA Inc. It relates to a surgical system for surgical retraction. The surgical system can include anchor extensions that can be attached to bone screws. The bone screws can be inserted into a pedicle of a vertebral body. A retractor can be attached to anchor extensions connected to adjacent vertebrae on an operational side. The retractor can be attached to anchor extensions connected to adjacent vertebrae on a contralateral side. The retractor can be used to distract the vertebral disc space between the adjacent vertebrae.

US9307972B2 was published in April 2016 on behalf of NuVasive Inc. The extensive publication relates to implants, instruments, and methods for performing surgical procedures on the spine, including one or more of creating an operative corridor to the spine, delivering implants to the spine, fusing one or more segments of the spine, and fixing one or more segments of the spine. The publication describes various embodiments of a fixation system that includes bone anchors, spinal rods, and an inserter for delivering and attaching the fixation system to the spine. The patent also describes various embodiments of a retractor system that includes retractor blades, a hoop, and a retractor frame for creating an operative corridor to the spine and retracting tissue during the procedure. The patent further describes various embodiments of a method for performing the transforaminal lumbar interbody fusion (TLIF) procedure using the fixation system and the retractor system.

SUMMARY OF THE DISCLOSURE

The degeneration of spinal bones and intervertebral disc can be congenital or caused by trauma, disease or aging. Such a degeneration can cause abnormal positioning and movement of the vertebrae, which can put pressure on nerves that pass between the vertebral bodies, thereby causing pain and possible nerve damage. To alleviate the caused pain, it is helpful to maintain or restore the natural distance between the vertebral bodies and to re-align the C-spine in order to reduce the pressure on the nerves running between the vertebrae. The most commonly use approach to re-aligning the C-spine and correction of the kyphosis is referred to Anterior Cervical Disectomy/Corpectomy and Fusion (ACDF), whereby hyperlordotic cervical cage designs or anterior cervical plating techniques facilitate the lordosis reconstruction. During the anterior cervical surgery for degenerative, traumatic, congenital and destructive lesions, re-aligning the C- spine to a physiologic and lordotic shape is important. Thereby, the changes of the neck and cervical spine alignment must be achieved safely in a stepwise, gradually controlled and reproducible manner. Therefore, a position change during surgery has to be ensured. Although this challenge is well known, alternative surgical distractors have not yet yielded satisfactory results and the exact restoration and achievement of target alignment remains inconvenient. Especially in the case of not very flexible spines, the results are particularly unsatisfactory. This, because the known distractors either only have a pure distraction or the ratched-like change of angulation of two adjacent vertebral bodies is achieved by a vertebral body pin rigidly connected to the cervical distractors.

It is therefore an object of the present disclosure to advance the state of the art with respect to surgical distractors. In particular, it is an object to provide an anterior cervical lordosis distractor to enable an exact, gradual, safe and reproducible distraction restoration of cervical lordosis and to enable intervertebral distraction with pins moving along the arch of the physiologic cervical lordosis and surgical center of correction.

The present disclosure relates to a surgical distractor suitable for temporary distraction of two adjacent vertebral bodies of a patient’s spine during a surgical procedure. The surgical distractor usually comprises a guide rod extending in a first direction. It further comprises and a first pin and a second pin, which during operation are interconnected to the guide rod by a first joint and a second joint assigned to them. The first and the second joint are linearly displaceable with respect to each other. The surgical distractor further comprises at least one locking mechanism which provides a locked position, in which the first and the second pin are arranged non-tiltable with respect to each other, and an unlocked position, in which the first pin and the second pin are arranged tiltable with respect to each other. The unlocked position therefore allows a change in the angulation of the two adjacent vertebral bodies with a simultaneous distraction. Thereby it can be achieved that during displacement the center of rotation is located such that the two adjacent vertebral bodies move in a natural way without building up residual forces which may result in an unwanted distortion and potential injury. In a preferred variation, the at least one locking mechanism provides an open position in which the first and the second pin are detachable from the respective joint. Good results can be achieved when the first and/or the second joint incorporate the at least one locking mechanism.

A simple and robust construction can be achieved when the at least one locking mechanism comprises a shaft extending in a second direction arranged essentially perpendicular to the guide rod. A sleeve is arranged rotatable with respect to the shaft between the locked position, the unlocked position, and the open position. As will be explained hereinafter in more detail, the first and the second pin are in the mounted position arranged in a third direction essentially perpendicular to the guide rod and the shaft. In a preferred variation the sleeve comprises a recess in which a locator is arranged protruding from the shaft. The recess in combination with the locator preferably defines the relative movement possible between the sleeve and the shaft during operation. If appropriate, a design with inverse arrangement is possible in which the locator is arranged at the sleeve and the recess at the shaft. The locking mechanism may in addition comprise a positioning element to indicate during operation at least one of the locked position and/or the unlocked position and/or the open position. If appropriate the locking mechanism may comprise a first notch, a second notch, and a locking element which in combination define the locked position, the unlocked position and the open position. Further details are again provided hereinafter.

A reliable and slim design which does not affect the line of sight can be achieved, when the sleeve comprises a spring tongue configured to, during operation, clamp the first and the second pin with respect to the respective shaft. The spring tongue usually extends essentially parallel to the shaft and is preferably formed integrally with the sleeve, wherein the spring tongue is preferably separated from the sleeve by a gap. In this case, the respective shafts preferably comprise a receptacle configure to receive a thereto corresponding pin. Good results can be achieved, when the receptacle is a channel arranged laterally in the shaft. The thickness of the shaft is such that the channel reaches approximately to the middle of the shaft. The channel preferably is curved (bend inwardly) in its longitudinal direction, i.e. in the third direction, and comprises a first section and a second section merging into each other. The first section is essentially perpendicular to the guide rod and the second section is arranged at a maximum tilting angle a of the pin with respect to the guide rod. In the unlocked position, the sleeve is arranged rotatable around the shaft, when the pin is arranged in the channel, such that during tilting of the pin with respect to the shaft the sleeve can follow the pin.

Alternatively or in addition, the surgical distractor may comprise features to determine the alignment of the pins based on the linear distraction. Good results can be achieved when a scale is attached to the linear guide rod which helps to indicate the relative displacement of the first pin with respect to the second pin. The scale may be linear or non-linear depending on the values to be indicated.

The first and the second pin, each may comprise at a distal end a threaded portion configured to, during operation, penetrate and temporarily lock to the respective vertebral body. Good results can be achieved, when each of the first and the second pin comprise above the threaded portion a support. The support protruding laterally above a side surface of the pin and provide in a mounted position when the threaded portion of the pin is inserted into a vertebral body, a torque support. In addition, the support may prevents the pins from being penetrating to deeply into the vertebral body as the support engages on the vertebral body and therefore limits the insertion of the respective pin. The support may be essentially disc shaped and/or arranged off-center with respect to a center axis of the corresponding pin and protruding away from each other in an outward direction. An off-center arrangement of the support may provide better access during the surgical procedure. The support shall face cranially or caudally of the intended area of correction in such a manner that a cervical anterior plate can be easily placed with its ends caudal or cranial to the respective pin without impinging to the support part of the pin. To arrange the support in the correct position, i.e. protruding away from each other, while the respective pin is inserted into a vertebral body, the support is advantageously arranged rotatably about the corresponding pin.

To prevent movements in the third direction, perpendicular to the guide rod and the shaft, of the pin, the first and the second pin may comprise a protrusion which interacts in a mounted position with the locking mechanism.

Alternatively or in addition, the first and the second pin, each may comprise at a proximal end a handle. The handle may facilitate the manual insertion of the threaded portion of the pins into the vertebral bodies.

For linear displacement of the first pin with respect to the second pin or the first joint with respect to the second joint respectively, along the guide rod, the surgical distractor comprises usually an expanding mechanism. The expanding mechanism may comprises a sled which is linearly displaceable with respect to the guide rod. The expanding mechanism may further comprise a latching tongue which is displaceable in an expanding direction along the first direction, and self-locking in an opposite contracting direction along the first direction. Good results can be achieved when the expanding mechanism comprises a toothed gear which is ar- ranged rotatable with respect to the sled and interacts with a linear gear which is arranged at the guide rod. Thereby, the toothed gear may act as a driver in combination with the linear gear to displace the sled with respect to the guide rod.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure described herein will be more fully understood from the details description given herein below and the accompanying drawings, which should not be considered limiting to the disclosure described in the appended claims.

The drawings show:

Fig. 1 A schematic top down view of a variation of a surgical distractor according to the disclosure; Fig. 2 A schematic bottom up view of the variation of Fig. 1 ;

Fig. 3 An exploded view of the variation of Fig. 1 ;

Fig. 4 A surgical distraction of the variation of Fig. 1 in an open position;

Fig. 4a: A detailed view of section A of Fig. 4;

Fig. 5: A surgical distraction of the variation of Fig. 1 in an open position; Fig. 5a: A detailed view of section B of Fig. 5;

Fig. 6: A surgical distraction of the variation of Fig. 1 in an unlocked position;

Fig. 6a: A detailed view of section C of Fig. 6;

Fig. 7: A surgical distraction of the variation of Fig. 1 in a locked position;

Fig. 7a: A detailed view of section D of Fig. 7.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Indeed, embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

Figures 1 to 7 show a variation of a surgical distractor 1 according to the disclosure. The surgical distractor 1 comprises a guide rod 2 extending in a first direction x and a first pin 3 and a second pin 4 interconnected to the guide rod 2 by a first joint 5 and a second joint 6 assigned to them. The first joint 5 and the second joint 6 are linear displaceable with respect to each other along the guide rod 2 by an expanding mechanism 27. In this variation, the first joint 5 is directly interconnected to the guide rod 2 while the second joint 6 is interconnected to the guide rod 2 by the expanding mechanism 27. The surgical distractor 1 further comprises two locking mechanisms 7 one incorporated in the first joint 5 and one incorporated in the second joint 6. Each of the locking mechanisms 7 comprise a shaft 8 extending in the second direction y and a sleeve 9. Each of the shafts 8 comprise a receptacle 17 configured to receive the first pin 3 respective the second pin 4. In this variation, the receptacle 17 is a channel 17 and is arranged laterally in the respective shaft 8. The channels 17 are curved in the third direction z and each comprise a first section 18 and a second section 19 merging into each other. The first section 18 is essentially perpendicular to the guide rod 2 and the second section 19 is arranged at the maximum tilting angle a the first pin 3 and the second pin 4 with respect to the guide rod 2. The sleeve 9 is arranged rotatable with respect to the shaft 8. The sleeve 9 comprises a recess 10, wherein in the recess 10, a locator 1 1 is arranged which is attached to the shaft 8. Moreover, the sleeve 9 comprises a spring tongue configured to clamp the first and the second pin 3, 4 with respect to the respective shaft 8, in the locked and the unlocked position of the locking mechanism 7. To indicate the locked, unlocked and open position of the locking mechanism 7, each of the locking mechanism 7 further comprises a positioning element 12. In this variation, both of the two locking mechanism 7 shown in Figure 1 are in the unlocked position in which the first and the second pin 3, 4 are arranged tiltable with respect to each other.

As shown in Figures 1 to 7, each of the first and the second pin 3, 4 comprise at the distal end 20 a threaded portion 21 . The threaded portion 21 is configured to penetrate and temporarily lock the first and the second pin 3, 4 to the respective vertebral body during operation. Above the threaded portion 21 , the first and the second pin 3, 4 each comprise a support 22 protruding above the side surface 23 of the pin 3, 4. In this variation, the support is essentially disc shaped and arranged off-center with respect to the center axis 24 of the corresponding pin 3, 4 and the two supports 22 protruding away from each other in outward direction. In this variation, the two supports 22, are arranged rotatable about the corresponding pin 3, 4. Furthermore, in this variation the first and the second pin 3, 4 comprise a protrusion 25 which interacts in a mounted position with the locking mechanism 7 to prevent movements of the first and the second pin 3, 4 in the third direction z and a handle 26.

As shown in Figure 2 and 3, the expanding mechanism 27 comprises a sled 28 which is linearly displaceable with respect to the guide rod 2 and a latching tongue 29 which is displaceable in the expanding direction along the first direction x and self-locking in the opposite contracting direction along the first direction x. The expanding mechanism 27 comprises a toothed gear 30 which is arranged rotatable with respect to the sled 28 and interacts with a linear gear 31 arranged at the guide rod 2. In combination, the toothed gear 30 and the linear gear 31 acts as a driver 32 to displace the sled 28 with respect to the guide rod 2.

Each of the locking mechanism 7 or each of the positioning element 12 respectively, further comprises a first notch 13, a second notch 14, and a locking element 15 which in combination define the locked position, the unlocked position and the open position of the locking mechanism 7 as shown in Figure 3. In this variation, the locking element 15 is a spring-loaded locking ball.

Figure 4 and 4a show a surgical distractor 1 in which the locking mechanism 7 of the first joint 5 is in the open position and the first pin 3 in an unmounted state. As can be seen in Figure 4a, in the open position of the locking mechanism 7, the spring tongue 16, which is integrally formed with the sleeve 9, leaves the channel 17 of the shaft 8, which is configured to receive the corresponding pin 3, free. In other words, in the open position of the locking mechanism 7, the receptacle 17 or channel 17 respectively, is not covered by the spring tongue 16. Thereby, the locator 1 1 is located in the recess 10 in the foremost possible position in second direction y.

In Figures 5 and 5a the surgical distractor 1 is shown wherein the locking mechanism 7 of the first joint 5 is in the open position and the first pin 3 is detachable from the first joint 5. As well as in Figures 4 and 4a, the channel 17 of the shaft 8 is not covered by the spring tongue 16 formed integrally with the sleeve 9 and the locator 1 1 is located in the recess 10 in the foremost possible position in second direction y.

Figures 6 and 6a show the surgical distractor 1 wherein the first pin 3 is in a mounted state and the locking mechanism 7 of the first joint 5 is in the unlocked position. Thereby, the spring tongue 16 covers the laterally to the shaft 8 attached receptacle and the first pin 3 arranged therein to clamp the first pin 3 to the shaft 8. The sleeve 9 is arranged rotatable around the shaft 8 while the recess 10 in combination with the locator 1 1 defines the relative movement possible between the sleeve 9 and the shaft 8 such that during tilting of the first pin 3 with respect to the shaft 8 the sleeve 9 can follow the first pin 3 and the first pin 3 can move from the first section 18 of the channel 17 into the second section 19, which is arranged at the maximum tilting angle a of the pin with respect to the guide rod

2. Figures 7 and 7a show the surgical distractor 1 wherein the first pin 3 is in a mounted state and the locking mechanism of the first joint 5 is in the locked position. As well as in Figures 6 and 6a, the spring tongue 16 covers the laterally to the shaft 8 attached receptacle and the first pin 3 arranged therein to clamp the first pin 3 to the shaft 8. In the locked position, the sleeve 9 is arranged not rotatable around the shaft 8 while the locator 11 is in a fixed and non-movable position in the recess 10. Therefore, the first pin 3 is fixed in the first section 18 of the channel 17 in a non-tiltable position essentially perpendicular to the guide rod 2 and the shaft 8.

LIST OF DESIGNATIONS

1 Surgical distractor 22 Support (pin)

2 Guide rod 23 Side surface (pin)

3 First pin 24 Center axis

4 Second pin 25 Protrusion

5 First joint 26 Handle

6 Second joint 27 Expanding mechanism

7 Locking mechanism 28 Sled (expanding mecha

8 Shaft nism)

9 Sleeve 29 Latching tongue

10 Recess 30 Toothed gear

11 Locator 31 Linear gear

12 Positioning element 32 Driver

13 First notch 50 Vertebral body

14 Second notch x first direction

15 Locking element y second direction

16 Spring tongue (sleeve) z third direction

17 Receptacle I channel (shaft)

18 First section (channel)

19 Second section (channel)

20 Distal end (pin)

21 Threaded portion (pin)

Claims

PATENT CLAIMS

1 . A surgical distractor (1 ), suitable for temporary distraction of two adjacent vertebral bodies of a patient’s spine during a surgical procedure, the surgical distractor (1 ) comprising: a. a guide rod (2) extending in a first direction (x) and a first pin (3) and a second pin (4) during operation interconnected to the guide rod (2) by a first joint (5) and a second joint (6) linearly displaceable with respect to each other, and b. at least one locking mechanism (7) which provides i. a locked position in which the first and the second pin (3, 4) are arranged non-tiltable with respect to each other, and ii.an unlocked position in which the first and the second pin (3, 4) are arranged tiltable with respect to each other.

2. Surgical distractor (1 ) according to claim 1 , wherein the at least one locking mechanism (7) provides an open position in which the first and the second pin (3, 4) are detachable from the respective joint (5, 6).

3. Surgical distractor (1 ) according to any of the preceding claims, wherein the first and/or the second joint (6) incorporate the at least one locking mechanism (7).

4. Surgical distractor (1 ) according to claim any of the preceding claims, wherein the at least one locking mechanism (7) comprises a shaft (8) extending in a second direction (y) and a sleeve (9) arranged rotatable with respect to the shaft (8) between the locked position, the unlocked position, and the open position.

5. Surgical distractor (1 ) according to claim 4, wherein the sleeve (9) comprises a recess (10) in which a locator (1 1 ) attached to and protruding from the shaft (8) is arranged, wherein the recess (10) in combination with the locator (1 1 ) defines the relative movement possible between the sleeve (9) and the shaft during operation.

6. Surgical distractor (1 ) according to any of the preceding claims, wherein the locking mechanism (7) comprises a positioning element (12) to indicate during operation at least one of the locked position and/or the unlocked position and/or the open position.

7. Surgical distractor (1 ) according to any of the preceding claims, wherein the locking mechanism (7) comprises a first notch (13), a second notch (14), and a locking element (15) which in combination define the locked position, the unlocked position and the open position.

8. Surgical distractor (1 ) according to any of the preceding claims 4 to 7, wherein the sleeve (9) comprises a spring tongue (16) configured to, during operation, clamp the first and the second pin (3, 4) with respect to the respective shaft (8).

9. Surgical distractor (1 ) according to any of the preceding claims 4 to 8, wherein at least one shaft (8) comprises a receptacle (17) configure to receive a pin (3, 4).

10. Surgical distractor (1 ) according to claim 9, wherein the receptacle (17) is a channel (17) arranged laterally in the shaft (8).

1 1. Surgical distractor (1 ) according to claim 10, wherein the channel (17) is curved in its longitudinal direction and comprises a first section (18) and a second section (19) merging into each other.

12. Surgical distractor (1 ) according to claim 1 1 , wherein the first section (18) is essentially perpendicular to the guide rod (2) and the second section (19) is arranged at a maximum tilting angle (a) of the pin with respect to the guide rod (2).

13. Surgical distractor (1 ) according to any of the preceding claims, wherein in the unlocked position, the sleeve (9) is arranged rotatable around the shaft (8), when the pin (3, 4) is arranged in the channel (17), such that during tilting of the pin (3, 4) with respect to the shaft (8) the sleeve (9) can follow the pin (3, 4).

14. Surgical distractor (1 ) according to any of the preceding claims, wherein the first and the second pin (3, 4) each comprise at a distal end (20) a threaded portion (21 ) configured to, during operation, penetrate and temporarily lock to the respective vertebral body.

15. Surgical distractor (1 ) according to claim 14, wherein the first and the second pin (3, 4) each comprise above the threaded portion (21 ) a support (22) laterally protruding above a side surface (23) of the pin (3, 4) for providing in a mounted position when the threaded portion (21 ) of the pin (3, 4) is inserted into a vertebral body (50) a torque support.

16. Surgical distractor (1 ) according to claim 15, wherein the support (22) is essentially disc shaped and/or arranged off-center with respect to a center axis (24) corresponding pin (3, 4) and protruding away from each other in an outward direction.

17. Surgical distractor (1 ) according to claim 15 or 16, wherein the support (22) is arranged rotatable about the corresponding pin (3, 4).

18. Surgical distractor (1 ) according to any of the preceding claims, wherein the first and the second pin (3, 4) comprise a protrusion (25) which interacts in a mounted position with the locking mechanism (7) and prevents movement in a third direction (z) of the pin (3, 4).

19. Surgical distractor (1 ) according to any of the preceding claims, wherein the first and the second pin (3, 4) comprise at the proximal end a handle (26).

20. Surgical distractor (1 ) according to any of the preceding claims, wherein the surgical distractor (1 ) comprises an expanding mechanism (27) for linear displacement of the first pin (3) with respect to the second pin (4) along the guide rod (2).

21 . Surgical distractor (1 ) according to claim 20, wherein the expanding mechanism (27) comprises a. a sled (28) which is linearly displaceable with respect to the guide rod (2) and b. a latching tongue (29) which is displaceable in an expanding direction and self-locking in an opposite contracting direction.

22. Surgical distractor (1 ) according to claim 20 or claim 21 , wherein the expanding mechanism (27) comprises a toothed gear (30) which is arranged rotatable with respect to the sled (28) and interacts with a linear gear (31 ) arranged at the guide rod (2), wherein said toothed gear (30) in combination with said linear gear (31 ) act as a driver (32) to displace the sled (28) with respect to the guide rod (2).