RU2750025C1 - Plate for ventral subaxial cervicospondylodesis and set of tools for its installation - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: plate for ventral subaxial cervicospondylodesis is made with a thickness of 0.4 mm and has a U-shaped cross-section and through holes for attaching the plate to each of the vertebral bodies with a single anchor. Punching is made across the entire surface of the plate to drain the sub-plate space. The plate shelves are at right angle to its wall and are made with a wavy edge for pressing into the bone. Perpendicular to the plate longitudinal axis, a rigid element of the “frame” type is placed. The set of tools for installing the above-mentioned plate includes tools for installing the above-mentioned plate – a stamp for making furrows and an impactor. The stamp for making furrows consists of a handle with a firing pin and a truss with a double blade placed on it for cutting a furrow in the anterior surface of the vertebral bodies. The impactor consists of a handle with a firing pin and a punch that follows the shape of the outer surface of the plate.

EFFECT: inventions provide for the implementation of ventral subaxial cervicospondylodesis without significantly changing the relief of the anterior surface of the mating vertebral bodies, the possibility of using the canal after removing the Kaspar distractor pin for anchor fixation without creating additional canals, the reduction in the plate standing in relation to the anterior surfaces of the vertebral bodies, the possibility of creating a low-profile plate, that is, reduction in the plate thickness, which will reduce the risk of postoperative dysphagia and simplify endoscopic examination, the possibility of using two types of fixation – pressing into the bone and anchor fixation, which is more effective in countering the tearing force, the possibility of modeling the plate shape, the improvement in the drainage of the sub-plate space and the possibility of increasing the load on the implant, which will create better conditions for the fusion of the vertebrae.

4 cl, 4 dwg

Description

The group of inventions relates to medicine, in particular to neurosurgery and traumatology, and is intended for fixing the vertebrae in ventral subaxial cervicospondylodesis in trauma and diseases of the lower cervical spine.

The most common surgical method for treating lower cervical spine injury with compression of the spinal cord and its roots is decompression with ventral subaxial cervicospondylodesis [1, 2].

An incision of the skin with subcutaneous tissue and platysma in the projection of the anterior edge of the sternocleidomastoid muscle. The scapular-hyoid muscle is retracted or, if necessary, transected. The scapular-hyoid muscle is adjacent to the fascia surrounding the neurovascular bundle, consisting of the common carotid artery, jugular vein and vagus nerve. The neurovascular bundle is retracted laterally. The pretracheal fascia surrounding the thyroid gland, esophagus, trachea, and the fascia surrounding the neurovascular bundle are separated. The anterior surface of the vertebral bodies is visualized, the intervertebral discs with the prevertebral fascia located above them, during the dissection of which the esophagus, located anterior to the vertebral bodies, should be medially retracted. After removal of the anterior sections of the disc, the pins of the Caspar interbody distractor are screwed into the middle third of the bodies of adjacent vertebrae parallel to the endplates [3]. Depending on the nature of the injury or disease, discectomy or corporectomy followed by corporodesis is performed.

To stabilize one or more of the operated spinal motion segments, the anterior cervical plate is applied.

Surgical treatment of trauma of the lower cervical spine is carried out by the method of interbody corporodesis in combination with a bone plate [4]. Stabilization with the anterior cervical plate contributes to the maintenance of the operatively obtained segmental distraction and lordosis after anterior cervical discectomy [5].

Known anterior cervical plate uNion ™ (From the material posted on the Internet at http://www.ulrichmedicalusa.com/home/spinal-implants/union/, date of treatment 07/27/2020), which is a rectangular titanium alloy implant with one or more windows, having 2 holes at each level, designed with a lordosis angle of 8 ° in the craniocaudal direction and an angle of 5 ° in the coronal plane of the plate, and has plate options from 1 to 4 levels (from 12 mm to 84 mm ) with a locking mechanism for self-drilling and self-tapping screws, which are used for fixation [6].

The disadvantage is the significant thickness of the plate (2 mm), more traumatic twin-screw fixation to each of the mating vertebral bodies, a rather high risk of migration of the structure, the complexity of performing revision operations in case of incompetent fusion.

Known cervical arthrodesis plate ABC2 [7] rectangular with oval holes, allowing the screw to adapt to the graft subsidence, and the screw has a spring-loaded locking mechanism.

The disadvantage is the significant thickness of the plate, fixation to each of the mating vertebral bodies with two screws, which is more traumatic, a rather high risk of migration of the structure, the complexity of performing revision operations.

Known system of front neck plates Trinica® Select [8] rectangular, which are contoured lordosely with paired round holes and a locking mechanism available between them for self-drilling or self-tapping, in various designs, screws.

The disadvantages include the need to take into account their trajectory when placing self-drilling screws. If the angle of the screw trajectory is too large, it may be impossible to completely seat the screw into the plate, which will cause difficulties in closing the locking mechanism, the significant thickness of the plate, fixation to each of the mating vertebral bodies with two screws, a rather high risk of migration of the structure, and the complexity of performing revision operations.

The known system of anterior cervical plates [9], which includes an elongated plate having paired holes for bone screws at opposite ends of the plate and slots for screws in the middle of the plate, located diagonally. At each end, there is one fixing screw that secures the heads of the bone screws in the sockets in the grooves around the perimeter of the plate holes. The locking screw provides a rigid fixation of the screws to the plate, while the screw heads do not protrude above the plate surface.

Known device [10], which includes a base plate and screw assemblies. Different abutment plates can span two or more vertebral bodies depending on the needs of a particular medical application. The plate has an elongated, preferably longitudinal opening with preferably serrated opposite edges. At the level of the discs, the plate has constrictions. There are claws on the lateral edges of the plate on the surface adjacent to the vertebrae. An alternative version of the plate has elongated horizontal, longitudinal and oblique holes. The screw assembly includes bone and internal screws having a thread, preferably tapered. The bone screw has a threaded channel coaxial to its longitudinal axis and an expandable head. Preferably, the expandable head has external teeth. Among the disadvantages can be called the complexity of the installation, which provides for the exact observance of the trajectory of insertion of the external screw into the vertebral body, in which its head would be optimally aligned with the slot in the plate, the difficulty of revision operations, the low efficiency of the claws as an element for fixing the plate, the low reliability of the conical threaded connection external and internal screws, a rigid toothed connection of the screw system can lead to loosening of the structure, especially in monosegmental fusion.

Known device for fixing vertebral segments [11], including a plate and screws. The plate is a rectangle with concave sides and rounded corners and four holes at the corners, as well as in the form of a section of a toroidal surface with a radius of curvature 39.7-40.3 mm in width and 170.5-171.5 mm in length. The screws are made in the form of a head and a rod with a threaded part and a smooth undercut. And the holes are in the form of a cylindrical part and a spherical seat for the screw head, and the axis of the cylindrical part of each hole is perpendicular to the chord of the lower surface of the plate with a large radius of curvature. The axis of each hole is directed at an angle of convergence of 5 ° to the axis of symmetry of the plate in the transverse direction. The diameter of the cylindrical part of the holes is equal to the diameter of the screw. The outer diameter of the screw thread is equal to the diameter of the smooth undercut. The screw head is made in the form of a parallelepiped in the upper part and a spherical surface in the lower part, and the profile of the spherical surface of the screw head corresponds to the profile of the spherical surface of the plate hole seat. The height of the screw head is equal to the height of the seat of the plate hole. The threaded part of the screw is made in the form of a thrust thread, and the inner diameter of the thread is made conical with a taper angle less than the self-locking angle. The length of a smooth undercut is 0.25-0.34 of the total length of the screw shaft.

The disadvantage is the significant thickness of the plate, fixation to each of the mating vertebral bodies with two screws without using for fixing the canals after removing the pins of the distractor, a rather high risk of migration of the structure, the complexity of performing revision operations.

The closest thing to the claimed device is the Osmium cervical system for anterior stabilization of the spine, which we have chosen as a prototype. (From the material posted on the Internet at http://www.ulrichmedicalusa.com/home/spinal-implants/union/, date of treatment 07/27/2020) [12], selected as a prototype. Rectangular plate with rounded corners and screw holes at each level, secured with expansion screws. There is a hole in the center of the plate. The Osmium screw consists of two parts, a large screw and a small screw. The latter is screwed into the larger screw and thereby expands its distal part. The design we have chosen as a prototype is shown in Fig. one.

The disadvantages of the device chosen as a prototype include:

1. Exclusively screw fixation of the plate, which leads to the fact that when the implant sags, the plate gains degrees of freedom in the vertical direction and to the right-left, thus creating a lever, the length of which is equal to the distance from the center of the screw to the edge of the plate, reinforcing the pull-out effect on the plate.

2. Traumatic fixation with 2 screws at each level, in which, in addition to the canals formed for the screws, a canal remains in the vertebral body, which remains after the distractor pin is removed.

3. Possibility of screw expulsion in the postoperative period, as well as migration of the structure and associated instability of fusion and the risk of esophageal perforation.

4. The high profile of the plate contributes to its significant standing relative to the anterior surfaces of the vertebral bodies.

5. The altered relief along the anterior surface of the vertebrae caused by the presence of the central hole and protruding screw heads, as well as the high profile of the plate, creating an obstacle in the form of the plate end, cause difficulties in endoscopic examinations and the risk of dysphagia.

6. Difficult drainage of the subplate space.

7. Osmium anterior spine stabilization cervical system reduces the load on the implant, which complicates consolidation (stress screening).

8. Inability to simulate the shape of the plate.

The objective of the invention is:

• reducing the trauma of fixing the plate;

• increasing the reliability of plate fixation and thereby reducing the risk of screw expulsion, as well as structure migration and associated unstable fusion and esophageal perforation;

• reducing the risk of postoperative dysphagia;

• simplification of endoscopic examinations performed through the esophagus, as well as reducing the risk of complications that may occur after these examinations.

The technical result of the invention is:

• performing ventral subaxial cervicospondylodesis without significant changes in the relief of the anterior surface of the bodies of the mating vertebrae;

• the possibility of using the canal after removing the pin of the Caspar distractor for anchoring without creating additional canals;

• decrease in the standing of the plate in relation to the anterior surfaces of the vertebral bodies;

• the possibility of creating a low-profile plate, that is, reducing the thickness of the plate, which will reduce the risk of postoperative dysphagia and simplify the endoscopic examination;

• the possibility of using two types of fixation - pressing into the bone and anchoring, which is more effective in countering the pulling force;

• the ability to simulate the shape of the plate;

• improved drainage of the subplate space;

• the possibility of increasing the load on the implant, which will create better conditions for the fusion of the vertebrae.

The technical result of the invention is achieved in that the claimed group of inventions includes a plate for ventral subaxial cervicospondylodesis and a set of tools for installing a plate for ventral subaxial cervicospondylodesis. The plate is made with a thickness of 0.4 mm, has a U-shaped section, and is equipped with through holes for attaching the plate to each of the vertebral bodies with one anchor. Notches are made over the entire surface of the plate to drain the sub-plate space. The shelves of the plate are at right angles to its wall and are made with a wavy edge for pressing into the bone. A stiffener of the "frame" type is located perpendicular to the longitudinal axis of the plate.

The technical result of the invention is also achieved in that the plate for ventral subaxial cervicospondylodesis is made in the form of a monosegmental plate with two holes, between which the frame is located or in the form of a two-segment plate having an additional stiffening element - the frame, and is made with three holes, between which the frames are located.

The technical result of the invention is also achieved in that the set of tools for installing a plate for ventral subaxial cervicospondylodesis includes a stamp for making grooves and an impactor. The stamp for making grooves consists of a handle with a striker and a truss with a double blade placed on it for cutting a groove in the anterior surface of the vertebral bodies. The impactor consists of a handle with a striker and a punch that repeats the shape of the outer surface of the plate.

The essence of the invention is illustrated in FIG. 2-4.

FIG. 2 shows a monosegmental plate, where:

5 - plate shelves with a wavy edge for pressing into the bone;

6 - a stiffening element of the "frame" type;

7 - through holes;

12 - notches for drainage of the sub-plate space.

FIG. 3 shows a two-segment plate, where:

5 - plate shelves with a wavy edge for pressing into the bone;

6 - a stiffening element of the "frame" type;

7 - through holes;

8 - additional stiffening element of the "frame" type.

FIG. 4 shows a set of instruments for inserting a plate for ventral subaxial cervicospondylodesis, where:

1 - stamp for making grooves;

2 - handle with a die striker;

3 - double blade placed on the stamp farm;

4 - stamp farm;

9 - impactor;

10 - impactor punch;

11 - impactor handle with striker.

The device works as follows:

After discectomy is performed and the interbody space is filled with autogenous bone material or its synthetic analogs, the place for the plate is marked. In the case of discectomy after replacement of the disc with an implant, a monosegmental plate is used (Fig. 2). In the case of corporectomy, after replacing the resected body with an implant from one's own bone or its synthetic analogue, a two-segment plate is used (Fig. 3). With a stamp for making grooves (1), grooves are made in the cortical layer of the bone, for which the stamp is placed on the anterior surface of the vertebral bodies in the place where the plate will subsequently be placed. A hammer is used to strike a handle with a stamp striker (2), a double blade (3), placed on the stamp farm (4), cuts grooves in the anterior surface of the vertebral bodies. The connection of the double blade (3) with the handle with the striker (2) of the stamp through the truss (4) provides an overview of the cutting of the grooves, in which the shelves of the plate with a wavy edge are placed for pressing into the bone (5), the relief of which facilitates pressing into the bone, and the stiffening element of the "frame" type (6) is placed between two through holes (7) at the level of the middle of the remote disc in a monosegmental plate (Fig. 2). An additional stiffening element of the "frame" type (8) is placed between three through holes (7) in a two-segment plate (Fig. 3). The plate is pressed into the bone with shelves with a wavy edge (5). The plate is pressed using an impactor (9) with a poison (10), the impactor (9) is placed on the front surface of the plate and the impactor handle with a striker (11) is hit with a hammer. Notches (12) in the plate will further facilitate the drainage of the sub-plate space.

Distinctive essential features of the invention and the causal relationship between them and the achieved technical result:

• Plate thickness - 0.4 mm, that is, the plate is made low-profile, which reduces its standing relative to the anterior surfaces of the vertebral bodies, reducing the risk of dysphagia and does not interfere with endoscopic examinations.

• The plate has a U-shaped cross-section, which, along with the anchor one, allows the "thorn-groove" attachment due to the lateral pressing into the bone and increases the rigidity of the structure, allows low-amplitude rotational movements in the stabilized segment, which favors fusion.

• The plate is equipped with through holes for attachment to each of the vertebral bodies with one anchor, which reduces the trauma of fusion. In addition, in comparison with screw, anchoring is more reliable and more resistant to pulling out.

• Notches made across the entire surface of the plate facilitate better drainage of the space created under the plate.

• The flanges of the plate are at right angles to its wall and are made with a wavy edge.

The arrangement of the plate shelves at right angles to its wall increases the strength of the plate and excludes deformation of the plate during pressing.

The wavy edges of the flanges of the plate experience less resistance when the plate is pressed in.

• Perpendicular to the longitudinal axis of the plate there is a stiffening element of the "frame" type, due to which the lateral sides of the plate do not move apart and do not converge at the corners during pressing.

• The plate is made two-segment, which makes it possible to use it in the case of corpectomy after replacing the resected body with an implant from its own bone or its synthetic analogue.

• The plate is made monosegmental, which can be used for discectomies.

• A stamp for making furrows consists of a handle with a striker and a truss with a double blade placed on it.

The location and shape of the blades follows the location and shape of the sides of the plate to facilitate insertion.

• The impactor consists of a handle with a striker and a punch that repeats the shape of the outer surface of the plate to evenly distribute the load over the entire surface of the plate during pressing.

We give clinical examples of approbation of the invention: Clinical example 1. Patient S., 56 years old, was injured when falling into the basement. In neurological status: Clinical presentation of the complete transverse spinal cord. With RCT - examination there is a dislocation of the C4 vertebra. Performed open reduction of dislocation, ventral subaxial cervicospondylodesis C4-C5 with fixation by the claimed device - a monosegmental low-profile U-shaped plate with anchor fixation for subaxial cervicospondylodesis. With control CT on the next day and X-ray on the 7th day after the operation - the dislocation is adjusted, the position of the plate is satisfactory. Significant regression of neurological deficit was noted within the first days after reduction and stabilization.

When transferred to rehabilitation treatment on the 23rd day, a decrease in the muscle strength of the hands and weakness of the left deltoid muscle remain in the neurological status. On examination after 4 months, complete restoration of impaired functions was observed; with CT, normal ratios of the vertebrae with the formation of a bone block at the level of injury, the position of the plate and anchors was satisfactory.

Clinical example 2. Patient L, 19 years old, was admitted after an injury while doing parkour. In the neurological status - the syndrome of complete impaired conduction of the spinal cord (grade A), upper coarse paraparesis, lower flaccid paraplegia, pain and temperature hypesthesia in dermatomes C6-C7, anesthesia distal to C8 according to the conductive type of all types of sensitivity. Dysfunction of the pelvic organs by the type of delay. When RCT examination - comminuted compression fracture 01 ,. type C with 60% deficit of the lumen of the spinal canal, kyphotic deformity. Diagnosis: "Closed complicated spinal cord injury. Compression comminuted fracture 01. Spinal cord injury with compression at the level of the fracture." Operated urgently: corporectomy 01. Ventral cervicospondylodesis of the Sb-DI own bone with fixation with a bony plate. Control CT 2 days and 3 weeks after surgery showed that compression and kyphotic deformity were eliminated, and the position of the bone implant, plate and anchors was satisfactory. Transferred to rehabilitation treatment for 27 days. In neurological status - an increase in strength in the arms, spasticity in the legs. Pelvic and sensory disorders persist.

Clinical example 3. Patient O., 52 years old, was admitted with complaints of pain in the cervical spine with irradiation to the left upper extremity, feeling of "cottony" legs. Movement in the cervical spine is limited forward and to the left. Muscle tone of the left shoulder is reduced, muscle wasting of the left hand. Tendon and periosteal reflexes are sharply revitalized. Pathological foot marks are not identified. Radicalgia C5-C6 on the left. Hypesthesia in dermatomes C5-C6 on the left.

According to MRI and RCT of the cervical spine, stenosis of the spinal canal at the level of C5-C6. Diagnosis: "Degenerative-dystrophic disease of the spine. Degenerative stenosis of the spinal canal at the C6 level." The planned operation was performed - corporectomy C6. Ventral cervicospondylodesis C5-C7 with own bone with fixation by the claimed device. After the operation, the neurological deficit and pain syndrome completely regressed. Control CT after 2 days and X-ray 10 days after the operation showed that the compression was eliminated, the position of the bone implant, plate and anchors was satisfactory. Discharged on the 12th day after surgery.

The claimed invention has been successfully tested in 12 patients, of whom 7 were operated on due to trauma of the cervical spine, 5 - in connection with degenerative-dystrophic diseases of the lower cervical spine.

Titanium, polyetheretherketone, carbon fiber and their combinations are used as materials for the manufacture of the group of inventions.

Thus, the claimed low-profile U-shaped plate with anchor fixation for subaxial cervicospondylodesis, in contrast to the prototype, provides:

• performing ventral subaxial cervicospondylodesis without significant changes in the relief of the anterior surface of the bodies of the mating vertebrae;

• the possibility of using the canal after removing the pin of the Caspar distractor for anchoring without creating additional canals;

• decrease in the standing of the plate in relation to the anterior surfaces of the vertebral bodies;

• the possibility of creating a low-profile plate, that is, reducing the thickness of the plate, which will reduce the risk of postoperative dysphagia and simplify the endoscopic examination;

• the possibility of using two types of fixation - pressing into the bone and anchor fixation, which is more effective in countering the pulling force;

• the ability to simulate the shape of the plate;

• improved drainage of the subplate space;

• the possibility of increasing the load on the implant, which will create better conditions for the fusion of the vertebrae, which together:

• reduces the trauma of fixing the plate;

• increases the reliability of plate fixation and thereby reduces the risk of expulsion of screws, as well as migration of the structure and associated unstable fusion and perforation of the esophagus;

• reduces the risk of postoperative dysphagia;

• simplifies the conduct of endoscopic examinations performed through the esophagus, and also reduces the risk of complications that may occur after these examinations.

Literature:

1. Kwon BK, Vaccaro AR, Grauer JN, Fisher CG, Dvorak MF. Subaxial cervical spine trauma. J Am AcadOrthop Surg. 2006; 14 (2): 78-89. doi: 10.5435 / 00124635-200602000-00003

2. Oner C, Rajasekaran S, Chapman JR, et al. Spine Trauma-What Are the Current Controversies ?. J Orthop Trauma. 2017; 31Suppl 4: S1-S6. doi: 10.1097 / BOT.0000000000000950.

3. Baskov Andrey Vladimirovich. Technique and principles of surgical treatment of diseases and injuries of the spine: a practical guide / A.V. Baskov, I.A. Borshchenko. - Moscow: GEOTAR-Media, 2007 .-- 131 p.

4. Valeev E.K., Valeev I.E. Surgical aspects of the treatment of injuries of the cervical spine // Practical medicine. 2013. No. 1-2 (69).

5. Herrmann AM, Geisler FH. Geometric results of anterior cervical plate stabilization in degenerative disease. Spine (PhilaPa 1976). 2004; 29 (11): 1226-1234.

6. From the material posted on the Internet at the website http://www.ulrichmedicalusa.com/home/spinal-implants/union/, date of access 07/27/20),

7.https://www.bbraun.ru/ru/products/b/abc2.html

8.http: //altermedica.ru/wp-content/uploads/2015/03/SHejny-e-plastiny-_TrinicaSelect.pdf

9. Patent US5364399A, 1994.

10. US patent 6776781 B1, 2004

11. Patent RU 2711612 C1, 2020.

12. From the material posted on the Internet at the website http://www.ulrichmedicalusa.com/home/spinal-implants/union/, date of access 27.097.20

Claims (4)

1. Plate for ventral subaxial cervicospondylodesis, characterized in that the plate is 0.4 mm thick and has a U-shaped cross-section, is equipped with through holes for attaching the plate to each of the vertebral bodies with one anchor, while on the entire surface of the plate there are cutouts for drainage of the subplate space, and the flanges of the plate are at right angles to its wall and are made with a wavy edge for pressing into the bone, in addition, a stiffening element of the "frame" type is placed perpendicular to the longitudinal axis of the plate. 2. Plate for ventral subaxial cervicospondylodesis according to claim 1, characterized in that the plate is made monosegmental with two holes, between which the frame is located. 3. The plate for ventral subaxial cervicospondylodesis according to claim 1, characterized in that it has an additional stiffening element - a frame and is made three-segment with three holes, between which the frames are located. 4. A set of tools for installing the plate according to PP. 1-3 for ventral subaxial cervicospondylodesis, including tools for installing the above plate - a stamp for making grooves and an impactor, while the stamp for making grooves consists of a handle with a striker and a truss with a double blade placed on it for cutting a groove in the anterior surface of the bodies vertebrae; the impactor consists of a handle with a striker and a punch that repeats the shape of the outer surface of the plate.

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