Spreading tool for use in dorsal procedures on a spine

Abstract

Spreading tool (1) for use in dorsal procedures on a spine, comprising a first and second spreading arm (41, 42) connected to each other via a joint (3) with a handle section (340) arranged on a first end section (31) for operating the spreading tool (1) and a first and second tool section (310, 320) arranged on a second end section (32) opposite the first end section (31) for clamping against a first and second spinous process (21, 22) of a spine, so that the adjacent tool sections (310, 320) are clamped, wherein the tool sections (310, 320) each comprise at least one first and one second recess (321, 322) on their end faces in order to be brought into positive contact with the spinous process (21, 22) of a vertebral body and in each of the recesses (321,322) on the inside each of which an inwardly directed engagement projection (330) is arranged for fixing the spreading tool (1) in the spinous process (21, 22).

Description

[0001] The invention relates to a spreading tool for use in dorsal procedures on a spine according to the independent claim.

[0002] The invention lies in the technical field of an interspinous spreading system for spinal surgery, for opening, enlarging and stabilizing a spinous process space for the surgical treatment of position-related diseases and deformities of the spine.

[0003] From CN 104161580 A, an expansion instrument for the intervertebral space of the lumbar spine is known. This spreading instrument can effectively widen the space between the spinous processes of the lumbar spine and enlarge the intervertebral space of the lumbar spine. Simultaneously, it effectively prevents the spinous processes from detaching from the spreading instrument. An expander body is formed by connecting two expander rods via a rotating shaft. The front ends of the expander rods are curved and connected to the respective spreading openings. The spreading openings can adapt to spinous processes of varying thicknesses, and screw holes of different lengths are provided at the upper ends of the spreading openings.Since the screws for temporary fixation are inserted according to the height of a patient's spinous processes, it can be prevented that the spinous processes detach from the expansion holes during treatment of the intervertebral space, thus preventing an expander from sinking in and pressing on the dural sac.

[0004] In the center of the spreader bars is a parallel spreader consisting of sliding chutes and an X-shaped component with sliding wheels. The rear ends of the spreader bars are equipped with handles, and the locking devices at the ends of the handles are connected via a threaded rod and a lock nut. This expansion instrument for the intervertebral space of the lumbar spine is easy to use, convenient to apply, and can safely and reliably expand the intervertebral space of the lumbar spine, thus facilitating the exposure of the surgical field. Furthermore, it reduces operating time, solves the problem of the lack of safe, specialized expansion tools for the intervertebral space of the lumbar spine in existing orthopedic instruments, and can be widely used for procedures involving the decompression of the posterior spinal canal of the lumbar spine.

[0005] The spinal canal is a cylindrical space in the center of the vertebral column, running axially (vertically in humans, horizontally in domestic animals). Within this space lie the spinal cord and the nerve bundle of the cauda equina, protected by the spinal cord. Diseases of the segmental bony structure can lead to changes such as bony outgrowths (spondylophytes, spondylosis), ligament thickening, and osteoarthritis of the facet joints (spondylarthrosis), which can result in narrowing of the spinal canal (spinal stenosis). These disease-related changes in the shape and position of the bony structures affect the spinal nerves exiting the spinal canal at each segment. Any movement, especially in cases of lumbosacral instability, can lead to progressive narrowing of the spinal canal and painful irritation of the nerves exiting it.

[0006] Over the course of a person's life, the joints undergo progressive degeneration. This particularly affects the small vertebral joints. Considerable scientific research has already been undertaken to explain the underlying causes. That degeneration is a factor is undisputed. The fact remains that, regardless of the specific causes, the joints and their components change to such an extent that it ultimately leads to misalignments and therapy-resistant spinal pain, significantly impacting quality of life.

[0007] Spinal surgeries have therefore increased significantly in recent years and require a very long operating time. The complexity of procedures within spinal surgery is also developing rapidly. This development includes technical innovations that continually present surgeons with new challenges.

[0008] Surgical treatment of dorsal spondylodesis takes some time. This is primarily due to the fact that, despite good development, the surgical instruments used only partially fulfill their function intraoperatively.

[0009] For dorsal spinal fusion surgery, a monosegmental interspinous spreader is used. The Chiari spreader is designed so that the angled arms are equipped with teeth at the end to grip the bone. This also further expands the facet joint. Then, the superior articular process, as part of the facet joint, is forcefully and bluntly removed.

[0010] Such rough manipulation often leads to dislocation of the retractor and frequently results in injuries to anatomical structures such as dural tears or nerve root damage. This represents a major disadvantage of current surgical retractors.

[0011] The invention aims to provide a spreading device that overcomes the disadvantages of the prior art and enables better fixation in the bone.

[0012] The problem is solved by a spreading device for maintaining a predetermined distance between adjacent spinous processes of a vertebral body, comprising the features of independent claim 1. Advantageous embodiments are the subject of the dependent claims.

[0013] The invention comprises a spreading tool for use in dorsal procedures on a spine, comprising a first and second spreading arm connected to each other via a joint, each with a handle section arranged at a first end section for operating the spreading tool, and each with a first and second tool section arranged at a second end section opposite the first end section, for clamping against a first and second spinous process of a spine, so that the adjacent tool sections are clamped, wherein the tool sections each have at least one first and second recess on their end faces in order to be brought into positive contact with the spinous process of a vertebral body, and in each of the recesses an inwardly directed engagement projection is arranged on the inside for fixing the spreading tool in the spinous process.This results in improved fixation of the spreading tool in the bone and thus prevents the tool from unintentionally slipping off the spinous process.

[0014] One advantageous aspect is that the recesses each have a U-shape. This allows the tool to optimally grip the mandible and ensures that the tool remains in the correct position even under high mechanical stress, such as hammer blows.

[0015] It is particularly advantageous if the U-shape of the recess has a radius at the open end. This prevents damage to the spinous process and surrounding tissue from the spreading instrument, thus ensuring the greatest possible medical and biological tolerability of the surgical procedure and avoiding undesirable side effects.

[0016] According to one preferred design feature, the insertion projection has a V-shape. This allows the insertion projection to be anchored particularly well in the bone, giving the spreading tool improved torsional stability.

[0017] Advantageously, the engagement projection is positioned centrally in the recess on a base section of the U-shape. This allows for precise positioning of the spreading tool on the vertebral body.

[0018] It has proven advantageous if the engagement projection is directed towards the open end of the U-shape of the recess. This allows the spreading tool to be attached particularly securely to the spinous process.

[0019] One advantageous aspect is that the engagement projection extends less than 50%, preferably between 10% and 40%, into the recess. This enables optimal force transmission and thus prevents the tool from slipping or twisting during the operation.

[0020] It is particularly advantageous if a bridge with locking elements is arranged on the first end section between the two spreading arms to engage with a projection on the opposite first end section, thus fixing the spreading tool in an extended position. This allows the spreading tool to be set very precisely to a specific position.

[0021] The invention will now be explained in more detail with reference to a drawing. The drawing shows: Fig. 1 a schematic representation of a spreading tool according to the invention for use in dorsal procedures on a spine; Fig. 2 a schematic detailed representation of tool sections of a spreading tool according to the invention, each with a recess; Fig. 3 A schematic representation of a spreading tool according to the invention arranged between two adjacent spinous processes of a vertebral body in a spine from two perspectives of the spine; and Fig. 4 a conventional spreading tool for surgical procedures on a spine according to the state of the art.

[0022] Fig. Figure 1 shows a spreading tool 1 according to the invention for use in dorsal procedures on a spine, comprising a first and second spreading arm 41, 42 connected to each other via a joint 3, each with a handle section 340 arranged on a first end section 31, 32 for operating the spreading tool 1, and each with a first and second tool section 310, 320 arranged on a second end section 32 opposite the first end section 31, for clamping against a first and second spinous process 21, 22 of a spine, so that the adjacent tool sections 310, 320 are clamped, wherein the tool sections 310, 320 each comprise at least one first and second recess 321, 322 on their end faces in order to be brought into positive contact with the spinous process 21, 22 of a vertebral body and in each of the recesses 321,322, each of which has an inwardly directed engagement projection 330 on the inside for fixing the spreading tool 1 in the spinous process 21, 22.

[0023] At the first end section 31 between the two spreading arms 41, 42, a web 5 with locking elements arranged on it is arranged for engagement with a projection arranged on the opposite first end section 31 in order to fix the spreading tool 1 in an open position.

[0024] After the spreading tool 1 is fixed between the two spinous processes 21, 22, a predetermined distance between the two adjacent spinous processes 21, 22 of the vertebral body is set and maintained during the intervention via the detent elements arranged on the web 5 and the corresponding projection located on the opposite end section 31.

[0025] The opposite end section 31 is in each case the end section 31 opposite the first end section 31, on which the web 5 is arranged.

[0026] In Fig. Figure 2 shows a schematic detail of tool sections 310, 320 of a spreading tool 1 according to the invention, each with a recess 321, 322. It can be seen that the engagement projection 330 for fixing the spreading tool 1 in the mandrel process 21, 22 is arranged on a base section of the U-shape of the recess 321, 322. The recess 321, 322 each has a U-shape.

[0027] The U-shape of the recess 321, 322 has a radius at the open end, i.e., at the outwardly directed end of the leg.

[0028] The engagement projection 330 has a V-shape.8 The engagement projection 330 is directed towards the open end of the U-shape of the recess 321, 322. The engagement projection 330 extends less than 50%, preferably between 10% and 40%, into the recess 321, 322.

[0029] Fig. Figure 3 shows a schematic representation of a spreading tool 1 according to the invention arranged between two adjacent spinous processes 21, 22 of a vertebral body in a vertebral column from two perspectives of the vertebral column. This illustration shows the use of a spreading tool 1 according to the invention during a dorsal procedure on a vertebral column.

[0030] A method for using a spreading tool 1 according to the invention on a spine during dorsal procedures comprises the following steps: a. Providing a spreading tool 1; b. Forming a positive-locking connection between a first recess 321 of a tool section 310 and a first mandrel extension 21; c. Forming a positive-locking connection between a second recess 322 of a second tool section 320 and a second mandrel extension 22; d. Spreading a first and second spreading arm 41, 42 around the first and second recess 321, 322 to clamp against the first and second mandrel extension 21, 22, so that the adjacent tool sections 310, 320 are clamped and a engagement projection 330 arranged in the recess 321, 322 engages in the mandrel extension 21, 22; e. Setting a distance between the first and second spreading arms 41, 42, in which at least one projection arranged on a first end section 31 engages in a detent element arranged on a web 5 arranged on the first end section 31 between the two spreading arms 41, 42 and thus fixes the spreading tool 1 in an extended position; f. Removal of a tissue structure of the spine; g. Release of the positive locking connection between the first recess 321 of the tool section 310 and the first mandrel extension 21; h. Release of the positive locking connection between the second recess 322 of the second tool section 320 and the second mandrel extension 22; and i. Removal of the spreader 1 from an operating area on the spine.

[0031] In step f, for example, the superior articular process, a component of the facet joint, is removed. Removing such a tissue structure requires considerable force; therefore, it is extremely important that the spreader 1 does not dislocate during the forceful, blunt removal of the superior articular process as part of the facet joint. Dislocation of the spreader 1 not infrequently leads to injuries of anatomical structures such as dural tears or nerve root injuries, causing the patient significant discomfort after the procedure. The insertion of the surgical projection 330 into the spinous processes 21, 22 ensures that the spreader 1 does not slip out of place.

[0032] Fig.Figure 4 shows a conventional, prior art retractor 1 for use in dorsal procedures on the spine. Such retractors 1 are a unique instrument designed for a variety of surgical procedures, such as laminectomies or other operations requiring spinal cord retraction. These retractors 1 are equipped with teeth that provide a secure grip on the tissue being manipulated without slippage. This retractor allows the muscle and soft tissue layers directly overlying the spinal cord to be moved aside. The ring handles and ratchet mechanism facilitate manual operation and locking at the appropriate width. Furthermore, this retractor features sharp prongs and articulated arms that ensure a firm grip on the tissue being retracted.

Claims

[1] Spreading tool (1) for use in dorsal procedures on a spine, comprising a first and second spreading arm (41, 42) connected to each other via a joint (3) with a handle section (340) arranged at a first end section (31) for operating the spreading tool (1) and a first and second tool section (310, 320) arranged at a second end section (32) opposite the first end section (31) for clamping against a first and second spinous process (21, 22) of a spine, so that the adjacent tool sections (310, 320) are clamped, wherein the tool sections (310, 320) each comprise at least one first and one second recess (321, 322) on their end faces in order to be brought into positive contact with the spinous process (21, 22) of a vertebral body and in each of the recesses (321,322) on the inside, an inwardly directed engagement projection (330) is arranged for fixing the spreading tool (1) in the spinous process (21, 22). [2] Spreading tool (1) according to claim 1, wherein the recess (321, 322) each has a U-shape. [3] Spreading tool (1) according to one of the preceding claims, wherein the U-shape of the recess (321, 322) has a radius at the open end. [4] Spreading tool (1) according to one of the preceding claims, wherein the engagement projection (330) has a V-shape. [5] Spreading tool (1) according to one of the preceding claims, wherein the engagement projection (330) is arranged centrally in the recess (321, 322) on a bottom section of the U-shape. [6] Spreading tool (1) according to one of the preceding claims, wherein the engagement projection (330) is directed in the direction of the open end of the U-shape of the recess (321, 322). [7] Spreading tool (1) according to one of the preceding claims, wherein the engagement projection (330) extends less than 50%, preferably between 10% and 40%, into the recess (321, 322). [8] Spreading tool (1) according to one of the preceding claims, wherein a web (5) with locking elements arranged thereon is arranged on the first end section (31) between the two spreading arms (41, 42) for engagement with a projection arranged on the opposite first end section (31) in order to fix the spreading tool (1) in an open position.

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