RU2063730C1 - Device for spondylodesis - Google Patents

Abstract

FIELD: medicine and can be used in neurosurgery, neurotraumatology, neuroorthopedics and traumatology. SUBSTANCE: device for spondylodesis is made as pin 1 of porous titanium nickeled with screw thread 2. The pin is built up of four radial sectors 5 formed by mutually perpendicular diametric longitudinal cuts; a through, axial, conically contracting in the distal third of the canal, hole passes inside the pin; the hole has a screw thread for screw 9, which is installed in the hole on the side of the proximal end for longitudinal movement with a successive uniform releasing of the sectors in the distal part of the pin. EFFECT: enhanced efficiency. 2 dwg

Description

 The invention relates to medicine and can be used in neurosurgery, neurotraumatology, neuroorthopedics and traumatology.

 A known construction [1] consisting of a rod with spirally fixed stationary spacer elements made in the form of ellipse rings with jumpers along the minor axis of material with shape memory, and the window is made in the rod, in which jumpers of spacer elements are installed.

 A known design for inter-articular atlanto-axial fusion [2] consisting of a metal pin with a screw thread, in the grooves of which are laid the wire and the head, selected as a prototype.

 The design is used as follows: after paratracheal access and exposure of the anterior surface of the upper cervical vertebrae, articular processes of the axis and lateral masses of the atlas are skeletonized. The design is screwed through the articular process of the axis into the cavity of the atlanto-axial joint into the lateral mass of the atlas on both sides.

 However, the design has a number of significant drawbacks.

 1. After the operation, a long external immobilization of the spine with a corset is required for a period of 8-10 months, the time of formation of the bone block in the area of the operation.

 2. Even with reliable external immobilization, after 3-4 weeks there will be a resorption of the spongy bone tissue around the metal, in connection with which the strength of the fixation of the rod is violated, the design is loosened because the bone block by this time does not have time to form, which leads to the inconsistency of fusion.

 3. The design head injures the surrounding soft tissue, as it does not enter the bone canal and causes swelling of the surrounding tissue.

 Thus, with the help of the above constructions, it is not possible to perform an initially reliable fusion.

 The purpose of the invention is the creation of a device for initially stable reliable fusion, which can significantly reduce the time of bed rest and external immobilization.

 The essence of the invention lies in the fact that a screw is inserted into the pin, and inside the pin made of porous titanium nickelide, there is a through axial hole with a screw thread, which is tapered in the distal third of its channel, and the pin is made up of four separate sectors formed mutually perpendicular diametrical longitudinal cuts, and the screw is installed in the hole from the side of the proximal end with the possibility of longitudinal movement to extend the sectors in the distal part.

 The through hole is made to move the screw. The cone-shaped narrowing of the channel in the distal third is intended for dosed expansion of the distal parts of the pin when moving the screw. After expanding the distal part of the sectors, a cone-shaped pin is created that reliably fixes the structure and the operated segment.

 The specified design allows to achieve the following advantages.

 1. Due to additional fixation by the divergent ends of the pin, migration, prolapse of the graft, trauma to the spinal cord and surrounding vessels are eliminated.

 2. Uniform compression by the sectors of the pin with a reliable exclusion of movements in the operated segment leads to initially stable spinal fusion and accelerate the formation of bone block.

 3. After the operation, the period of immobilization is reduced to 6 months, and bed rest to 7-10 days, which is of great importance for the early activation of patients and the prevention of complications. 4. The design is universal and can be applied in all parts of the spine.

 5. The use of porous titanium nickelide as the material for the pin eliminates the resorption of bone tissue around the structure and the violation of the fixation of the segment in a separate period of time.

 The invention is illustrated in the drawing, where figure 1 shows a General view of the device; figure 2 diagram of the installation of the pin between the bodies of the vertebrae.

 The device consists of a pin 1 with a screw thread 2, in the groove of which the wire 3 is helically laid, while the diameter of the wire is less than the depth of the groove. The pin is divided by two mutually perpendicular cuts 4 into four radial sectors 5. An axial through hole 6 is made inside the rod 6. The hole 6 in the distal third of the rod has a cone-shaped truss 7. The rest of the hole has a cylindrical shape. Hole 6 has no screw thread 8 over its entire length.

 A screw 9 is inserted into the hole 6, which, as it moves forward, gently pushes the sectors 5, fixing the structure in the segment being operated 10. The wire 11 serves to fix the radial sectors of the pin while screwing the pin between the vertebral bodies.

 The construction is used as follows.

 Under general anesthesia, access to the vertebral bodies is provided. A bone channel is formed between the vertebral bodies with a diameter less than a pin by a milling cutter. The pin 1, consisting of four radial sectors 5, fastened by a wire 3, laid in the grooves of the screw thread 2, is screwed into the groove between the vertebral bodies. Then screw 9 is screwed into the axial hole 6. Moving to the distal cone-shaped part 7, the screw extends the sectors 5 and fixes the structure and the operated segment. The wound is sutured in layers.

 After the operation, the term of bed rest is reduced to 7 days and external immobilization to 6 months.

 Thus, with the help of the proposed design, reliable interbody fusion is performed, the number of complications is reduced, the results of treatment of patients with spinal pathology are improved.

Example
The medical history N 1263. Patient M. was admitted to the HXO-1 GB September 29, 1990 with complaints of pain in the lumbar spine, aggravated after physical exertion, in an upright position. Sick for about 10 years, conservative treatment without effect. Objectively: orthopedic disorders in the lumbar spine in the form of a deepening lordosis, step-like deformation of the spinous processes of L4-5.

 Radiography: L5 spondylolisthesis of the vertebra due to spondylolysis of the second degree. Functional radiographs in the L5-C1 segment revealed instability. For the operation, the above construction was prepared. The pin length is 25 mm, the diameter is 24 mm, the diameter of the through channel is 12 mm, with a decrease in the distal third to 5 mm. 09.16.90. operation: interbody fusion L5-C1 device for interbody fusion with left-side retroperitoneal access. On the left, access to the spinal column was made between the left and right iliac veins, the L5-C1 disk was allocated. A discectomy was performed with a cutter with a diameter of 28 mm, grooves were formed in the bodies L5 and C1, 26 mm long. A pin is screwed into the groove, then a screw is screwed into the through hole of the pin. When screwing in the distal portions of the canal, the distal portions of the sectors parted with reliable fixation of the structure and segment of the spine. The wound is sutured in layers. The postoperative course is smooth, primary healing. On the 7th day after the operation, the patient was raised to a vertical position, on the 20th day he was discharged for outpatient treatment in a semi-rigid corset. He used the corset for 6 months, after a year the condition was satisfactory, no complaints.

 On the control functional radiographs, there are no movements in the operated segment; spinal fusion is consistent.

 1. The author's certificate of the USSR N 1584939, A 61 B 17/60, 1990.

 2. The author's certificate of the USSR N 1279629, A 61 V 17/60, 1986.

Claims (1)

 A device for spinal fusion containing a pin with an external screw thread, in the grooves of which a wire is laid, characterized in that a screw is inserted into it, and a screw axial hole passes through the pin made of porous titanium nickelide, which is in the distal third of its channel tapered, the pin is made up of four separate sectors formed by mutually perpendicular diametrical longitudinal cuts, and the screw is installed in the hole from the side of the proximal end with the ability to move longitudinally to move apart sectors in the distal part.

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