RU2307625C1 - Arrangement for spondylosyndesis - Google Patents

Abstract

FIELD: medicine; neurosurgery; traumatic surgery; orthopedics.

SUBSTANCE: arrangement has implant of vertebrae's body. The latter as top and lower bases made of porous titanium nickelide. There are central openings for mounting demountable connection in form of cylinder provided with flange, mounted in one base, and screw provided with flange entering the other base. Cylinder is mounted for movement and fixation. Arrangement additionally has on-bone rectangular plate, on-bone plate's lock to attach it to implant, and bone screws. On-bone plate is made in form of rectangle. It is curved along arc and it has opening in center for lock. It also has two oval-shaped openings in top part and two round openings at lower part for bone screws. Lock is provided with keeper. Bases are made in form of rings. Flanges of cylinder and screw are made hexahedral. Trough openings provided with thread for lock are made in side faces of flange. Flange of cylinder is disposed under top base. Flange of screw is disposed onto lower base. Edges of screw and cylinder are provided with central protrusions for being sunken into vertebra's bodies. Migration and development of implant is prevented; axial, kyphotic and scoliotic deformation of operated spinal column is reduced. Height of vertebrae's implant can be changed depending on size of bone wound formed after body of damaged vertebrae is removed.

EFFECT: improved reliability; higher degree of secure.

2 dwg

Description

The invention relates to medicine, namely to neurosurgery, traumatology, orthopedics for compression and compression-comminuted fractures of the vertebral bodies to restore support function of the spine, and can be used for unstable compression-comminuted fractures of the vertebrae.

A device for vertebral distraction is known (US patent 4553273, A61F 2/24, 1965), containing supporting elements and means for their dilution, made in the form of a nut mounted on a threaded rod and interacting with a threaded pusher.

However, there is a risk of spontaneous twisting, angular displacement and a repeated reduction in the distance between the vertebrae.

Endoprosthesis distractor N.A. Markova (A.S. USSR 1470289, А61В 17/60, 1989). The endoprosthesis distractor contains a housing with a threaded rod, while the ends of the housing and the rod have supporting platforms. The endoprosthesis distractor is equipped with an intermediate sleeve installed in the housing with the possibility of axial movement, and the rod is placed inside the intermediate sleeve. Basic platforms are supplied with teeth. The outer surface of the housing is made with longitudinal faces.

However, the supporting pads are made on the end surfaces of the housing and the rod, forming a single whole with them, which makes the structure rigid. Even at the slightest displacements of the vertebral bodies, the support areas with teeth destroy their bone structure, which ultimately leads to pathological mobility.

The closest in technical essence to the claimed invention is the “Endoprosthesis of the vertebral body” (AS USSR 1739989, A61B F 2/44, bull. No. 22, 06/15/1992), which contains two bases made of porous titanium nickelide, connected interconnected by a threaded flange connection containing a hollow cylinder with a flange and a thread on the inner surface and a screw with a flange and a protrusion that enters the upper base and serves to fix the screw in it in order to prevent reverse twisting. The screw has a longitudinal groove along the threaded part and is secured by a fixing screw, which passes through the lower base of the endoprosthesis and through the wall of the hollow cylinder, performing at the same time the function of the lock preventing it from rolling in the lower base of the full cylinder.

However, this endoprosthesis, without additional fixation with the bodies of neighboring vertebrae involved in the formation of fusion, cannot prevent scoliotic and kyphotic deformation of the operated portion of the spine during unstable compression-comminuted fractures of the vertebral bodies due to damage to the posterior supporting complex of the spine.

The objective of the invention is to increase the reliability of fixation of the endoprosthesis, preventing its migration and development after axial, kyphotic and scoliotic deformation of the operated spine, and the possibility of changing the height of the endoprosthesis of the vertebra depending on the size of the bone wound formed after removal of the damaged vertebral body.

This object is achieved in that the device for fusion contains an endoprosthesis of the vertebral body, consisting of an upper and lower base of porous titanium nickelide with central holes for installing a detachable connection in the form of a cylinder with a flange installed in one base, and a screw with a flange included in another base. The cylinder is mounted with the ability to move and fix. The device further comprises a osseous rectangular plate, a fixator of the osseous plate to the endoprosthesis and bone screws. In this case, the osseous plate is made rectangular, curved in an arc, with an oval hole in the center under the retainer, two oval holes in the upper part and two round holes in the lower part for bone screws. The lock is equipped with a lock nut. The bases are made in the form of rings. The flanges of the cylinder and screw are made hexagonal, and through holes with a threaded lock are made in the lateral faces of the cylinder flange. The cylinder flange is located under the upper base, and the screw flange is located on the lower base. The ends of the screw and cylinder are equipped with central protrusions for recession in the vertebral bodies.

Novelty of invention

- The device further comprises a osseous rectangular plate, a fixator of the osseous plate to the endoprosthesis and bone screws. In this case, the osseous plate is made rectangular, curved in an arc, with an oval hole in the center under the retainer, two oval holes in the upper part and two round holes in the lower part for bone screws. The lock is equipped with a lock nut. The plate, when fixed by bone screws through openings located in its upper and lower parts, to adjacent vertebral bodies and to the endoprosthesis by means of a fixator through an oval hole located in the center, allows for a more tight fit to adjacent vertebral bodies, which have a conditionally cylindrical shape. This prevents the endoprosthesis from moving after it is installed in all directions relative to the axis of the spine. The oval shape of the Central hole for the retainer and the oval shape of the holes in the upper part of the plate for bone screws allow you to install locking elements regardless of the height of the endoprosthesis.

- The bases are made in the form of rings. The base rings are made of titanium nickelide with an open porous structure (through porosity) close to the pore structure of the bone tissue.

- The flanges of the cylinder and screw are made hexagonal, and through holes with a threaded lock are made in the lateral faces of the cylinder flange. The cylinder flange is located under the upper base, and the screw flange is located on the lower base. The shape of the hexagon allows for the rotation of the cylinder to untwist the detachable joint, as a result of which the height of the endoprosthesis increases to the required size corresponding to the distance between the bodies of adjacent vertebrae. The latch is equipped with a lock nut, preventing its spontaneous unscrewing. The screw flange located on the lower base also has the shape of a hexagon, which contributes to its retention at the time of rotation of the cylinder. Through holes in the lateral faces of the hexagonal flange of the cylinder allow the cylinder to be fixed with an additional rotation of no more than 15 ° when installing the latch through the central oval hole of the osseous plate.

- The ends of the screw and cylinder are equipped with central protrusions for recessing the vertebrae into the body, to prevent the displacement of the endoprosthesis elements relative to adjacent vertebrae involved in the formation of fusion.

Using the proposed device for spinal fusion, a new result is achieved: the possibility of developing kyphotic and scoliotic deformity of the operated spine is prevented; it is possible to increase the height of the endoprosthesis depending on the required distance between the cortical plates of adjacent vertebral bodies; improved conditions for manipulating wrenches when changing the height of the endoprosthesis; the reliability of fixation is increased due to an additional plate fixed by bone screws to the bodies of adjacent vertebrae and a retainer to the endoprosthesis, as well as due to protrusions at the ends of the screw and cylinder while maintaining cortical plates of the bodies of adjacent vertebrae, which allows them to maintain their bearing ability.

The invention is illustrated by the drawings shown in figures 1 and 2

In Fig.1 - the device is assembled in longitudinal section,

figure 2 - plate in two projections (A is a front view, B is a bottom view).

The invention is directed to the creation of a device for fusion, providing reliable stabilization of the spine, consisting of an endoprosthesis of the vertebral body that has lost its support-fixation ability due to damage, and an additionally installed plate. The endoprosthesis of the vertebral body for spinal fusion contains the upper 1 and lower 2 bases of porous titanium nickelide in the form of rings with central holes for installing a detachable connection. The detachable connection includes a cylinder 3 with a hexagonal flange 4. The cylinder 3 is installed in the upper base 1, and the hexagonal flange 4 is located under the upper base. The detachable connection also contains a screw 5 with a hexagonal flange 6. A screw 5 enters the lower base 2, the hexagonal flange 6 is located on the lower base 2. The cylinder 3 is mounted with the possibility of movement and fixation relative to the screw 5. Through holes are made in the lateral faces of the hexagonal flange 4 with a thread 7 for a retainer 8, equipped with a lock nut 9. The ends of the screw 5 and cylinder 3 are provided with central protrusions 10. Additionally, the device includes a osseous rectangular plate 11, curved in an arc, with an oval hole in the center 12 under the retainer 8, two oval holes in the upper part 13 and two round holes in the lower part 14 for the bone screws 15.

A device for fusion is installed as follows.

In the position of the extension of the axis of the spine after a complete or partial resection of the vertebral body damaged as a result of an injury or other pathological process, an endoprosthesis of the vertebral body is installed in its place. In this case, grooves are formed in the cortical plates of the adjacent vertebral bodies for the central end protrusions 10 of the cylinder 3 and screw 5. In the twisted state, when the endoprosthesis is of the lowest height, it is installed in the bone wound, while screw 5 with the lower base 2 is fixed with a key for the hexagonal flange 6 in the position when the lower base 2 is adjacent to the cortical plate of the lower body of the vertebra, and the central protrusion 10 is recessed from the end into the groove prepared for it in this vertebra. Using another key, the cylinder 3 with the upper base 1 is twisted, increasing the height of the endoprosthesis, until the upper base 1 completely stops in the cortical plate of the body of the overlying vertebra, while the central protrusion 10 of the end face of the cylinder 1 is recessed into the body of this vertebra. With further unwinding of the cylinder 3 with the upper base 1 relative to the screw 6 with the lower base 2, it allows to increase the distance between the bodies of neighboring vertebrae, thereby eliminating kyphotic deformation and restoring the axis of the spine. Re-extension of the spine is eliminated. A preliminary fitting of an additional plate 11 is carried out, which is placed on a body of adjacent vertebrae with a concave surface so that its holes in the upper 13 and lower 14 parts are above the vertebral bodies, and the central hole 12 coincides with one of the through holes 7 of the hexagonal flange 4 of cylinder 3. When The need for this coincidence can be achieved by additional rotation of the cylinder 3 for the hexagonal flange 4 to 15 ° in both directions or in one to 30 °. After preliminary fitting, a clamp 8 is installed in the central hole of the plate 12 from the side of its convex surface, onto which the fixing nut 9 is screwed from the concave side of the plate 11. The plate 11 is finally placed on the vertebral bodies above the endoprosthesis of the vertebral body. The latch 8 is screwed into the through hole 7 of the hexagonal flange 4 of the cylinder 3. To prevent the latch from being unscrewed with the curved key from the ventral side of the plate 11, the nut 9 is finally tightened until the latch is immobilized. Bone screws 15 are screwed into the vertebral bodies through round holes 14 in the lower part of the plate 11 and oval holes 13 in the upper part.

Large fragments of the removed body of the damaged vertebra can be laid on the abdominal and lateral surfaces of the endoprosthesis of the vertebral body between the vertebrae. In the future, these fragments will be the basis for the formation of bone-nitinol block between the vertebrae. The surgical wound is sutured in layers. After removing the stitches, after 10 days, the patient is transferred to a vertical position. Seating is excluded for a month.

The inventive device for spinal fusion provides: reliable fixation and stabilization of the spine with elimination of kyphotic deformation of the axis of the damaged spine, early activation of patients, prevents kyphotic, axial and scoliotic deformity of the spinal column in the postoperative period.

Claims (1)

A device for fusion containing an endoprosthesis of the vertebral body, consisting of an upper and lower base made of porous titanium nickelide with central holes for installing a detachable connection in the form of a cylinder with a flange installed in one base, and a screw with a flange included in another base, the cylinder is installed with the ability to move and fix, characterized in that it further comprises a rectangular osseous plate, a fixative of the osseous plate to the prosthesis and bone screws, while the osseous plate it is rectangular, curved in an arc, with an oval hole in the center under the retainer, two oval holes in the upper part and two round holes in the lower part for bone screws, the retainer is equipped with a lock nut, the bases are made in the form of rings, the cylinder and screw flanges are made hexagonal, moreover, through holes with threaded fastener are made in the lateral faces of the cylinder flange, the cylinder flange is located under the upper base, and the screw flange is located on the lower base, the ends of the screw and cylinder are provided with a central E projections for embedding into vertebral body.

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