RU2229271C1 - Method and device for treating the cases of retrospondylolisthesis - Google Patents

Abstract

FIELD: medicine; medical engineering. SUBSTANCE: method involves accessing lesion zone of injured lumbar vertebral column segment by applying retroperitoneal access method. Pulpous core remnants and a part of pulpous ring between the shifted and inferior vertebra are removed. Device has a plate having ends bent towards opposite sides. One end of the plate is deflected under an acute angle and has cutting edge, the other one being bent at right angle and an opening is produced therein for receiving fixing screw. Implant repeating intervertebral disk shape is introduced between vertebra bodies. A device shaped as plate having ends bent towards opposite directions in a way that the cutting plate edge makes engagement with superior vertebra body. The plate is rotated in sagittal plane as far as possible until it thrusts against implant groove end face. In continuing plate rotation in sagittal plane, the superior vertebra is set to normal position from retrolisthesis one. Then, fixing screw is introduced through opening in the plate into inferior vertebra body. EFFECT: enhanced effectiveness of fixation; reduced risk of traumatic complications. 3 cl, 3 dwg

Description

The invention relates to medicine and is intended for the surgical treatment of retrospondylolisthesis (posterior displacement of the vertebra) in the lumbar spine.

A known method of treating vertebral displacements and a device for its implementation (Pat. RF No. 2155550, 2000), used in the treatment of spondylolysis spondylolisthesis (displacement of the anterior vertebra) in the lumbar spine. The method includes the introduction of the implant between the displaced and the underlying vertebrae, reduction and fixation of the displaced vertebra using a device for repositioning, which is inserted into a special groove of the implant. The implant has grooved supporting surfaces and repeats the shape of the intervertebral disc. The device for positioning includes a chisel-reponator with a locking rod.

However, it is impossible to use the known method for posterior vertebral displacements in the lumbar spine, since the pubic joint of the pelvic ring interferes with the rotation of the reponator bit in the sagittal plane from top to bottom.

A vertebral prosthesis is known (ed. St. USSR No. 1591973, IPC A 61 F 2/44, 1990), which is fixed by rods with curved ends.

However, the known solution can be used to completely replace the vertebral body and stabilize the vertebral segment, but it does not solve the problem of eliminating vertebral displacement during retrospondylolisthesis.

The task is to eliminate posterior displacement of the vertebra (retrospondylolisthesis), restore the height of the intervertebral gap and stabilize the damaged segment of the spine with the correct positioning of the vertebrae.

The problem is solved as follows.

In the method of treating retrospondylolisthesis, including the introduction of an implant between the displaced and the underlying vertebrae, the reduction and simultaneously fixation of the displaced vertebra using a device inserted into the groove of the implant, which repeats the shape of the intervertebral disk, according to the invention, the groove of the implant is made through and the device is inserted through it in the form of a plate with curved in opposite directions with the ends until the cutting edge of the insert adheres to the displaced vertebra, then the insert is rotated in the sagittal plane direction of the vertebra shifted posteriorly and stabilize it in the set position, fixing the end of the plate with a screw to the underlying vertebra. In this case, one end of the plate is bent at an acute angle and has a cutting edge, and the other is bent at a right angle and a hole is made for a fixing screw, while the bending angle of the end of the plate with the cutting face is determined based on the parameters necessary for the vertebra to be adjusted.

A through groove in the implant allows you to enter the adjusting device, create an emphasis for it and carry out the reduction of the shifted vertebra according to the type of lever of the second kind.

The design of the device in the form of a plate with oppositely curved ends allows the engagement of the cutting face with the body of the displaced vertebra, the support of the plate on the implant and the direction of the vertebra shifted posteriorly to achieve the correct relative position of the vertebrae in the vertebral segment and at the same time to stabilize the damaged segment of the spine by introducing a fixing screw.

As a rule, with retrospondylolisthesis, the posterior vertebral displacement is no more than 3-6 mm. Depending on this, the end of the insert with a cutting edge is bent at an angle calculated by the theorem of a right-angled triangle, while the amount of reduction will correspond to a small leg of the triangle.

Thus, the proposed method for the treatment of retrospondylolisthesis and a device for its implementation allows simultaneous reduction of the vertebra from the position of the retrolisthesis (posterior displacement) with minimal trauma to the vertebral bodies and at the same time stabilization of the vertebra in the corrected position, while the device reliably holds the implant in the intervertebral space.

The drawings show: FIG. 1. Intervertebral disc implant, general view; figure 2. Device for the treatment of retrospondylolisthesis; figure 3 (A-D). The treatment regimen for retrospondylolisthesis.

To implement the method, an implant and a device for the treatment of retrospondylolisthesis are used.

The implant (figure 1) repeats the shape of the intervertebral disc with grooved surfaces and has a through groove. The implant allows you to maintain a normal height of the intervertebral space, in addition, the corrugated surfaces of the implant contribute to the stability of the fixation of the intervertebral segment. Ceramic or titanium implants are used. The device for treating retrospondylolisthesis (Fig. 2) has the form of a plate with ends bent to opposite sides: one end is bent at an acute angle and has a cutting face, the other is bent at right angles and has an opening for a fixing screw. The plate material is titanium. Depending on the degree of vertebral displacement (3-6 mm), plates with different bending angles of the end with a cutting face are used. For example, suppose a vertebra needs to be adjusted from a position of posterior displacement of 6 mm. Then, based on the theorem of a right-angled triangle, the large leg (b) corresponds to the height of the intervertebral space (normal 12 mm), the minor leg (a) is 6 mm of the required reduction. Therefore, the bending angle of the end of the insert with the cutting face should be equal to 60 degrees (see the diagram of figa, g).

The method is as follows. By operative retroperitoneal access according to the method of V.D. Chaklin, the area of the affected lumbar segment is opened. The remains of the pulpous nucleus and part of the pulpous ring between the shifted and underlying vertebrae are removed. An implant repeating the shape of the intervertebral disc is inserted between the vertebral bodies (Fig. 3A). Then, a insert with ends curved in opposite directions is inserted into the through groove of the implant so that the cutting edge of the insert engages with the body of the overlying vertebra (Fig. 3B). The plate is rotated in a sagittal plane from top to bottom until it stops at the end of the groove in the implant. In this case, the cutting face moves further into the body of the overlying vertebra, creating a reliable grip of the face with the vertebral plate (Fig.3B). Continue the rotation of the plate in the sagittal plane until the overlying vertebra is repositioned from the position of the retrolisthesis (posterior displacement) to normal (Fig. 3G). Then the vertebra is stabilized in the set position, for which a fixing screw is inserted through the hole at the end of the plate into the body of the underlying vertebra. On this operational reception is completed.

The proposed method for the treatment of retrospondylolisthesis (posterior displacement of the vertebra) provides an open simultaneous, slightly traumatic and effective reduction of the displaced vertebra and at the same time its reliable stabilization in the repositioned position.

Claims (3)

1. A method of treating retrospondylolisthesis, including the introduction of an implant between the displaced and the underlying vertebrae, reduction and simultaneously fixing the displaced vertebra with the device, the implant repeats the shape of the intervertebral disc and has a groove, characterized in that the groove of the implant is made through and a special device is inserted through it in the form of a plate with ends bent in opposite directions, until the cutting edge of the plate adheres to a displaced vertebra, then turning the plate in the sagittal plane the direction of the vertebra shifted posteriorly is removed and stabilized in the repositioned position, fixing the plate with a screw to the underlying vertebra. 2. A device for the treatment of retrospondylolisthesis, made in the form of a plate with curved ends, characterized in that the ends are curved in opposite directions by the ends, while one end of the plate is curved at an acute angle and has a cutting face, and the other is curved at a right angle. hole for the fixing screw. 3. The device for the treatment of retrospondylolisthesis according to claim 2, characterized in that the end of the plate with a cutting edge is bent at an angle that is determined based on the parameters necessary for the management of the vertebra.

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