RU2568345C2 - Laminar hook electrode for posterior spinal fixation and epidural electric stimulation of medullar structures - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medical equipment. A laminar hook electrode for posterior spinal fixation and epidural electric stimulation of medullar structures comprises a hook body and a curved hook-shaped fixing part. The curved hook-shaped fixing part is configured as a one-piece base intraoperatively insertable under vertebral arches into a posterior epidural space. The curved hook-shaped fixing part envelopes an electrically conductive surface for medullar structure stimulation. The electrically conductive surface is limited from the electrode hook body by a dielectric pad and has a blind hole for cable electrode fixation. Dimensions of the electrically conductive surface surrounded by the dielectric pad make 0.5-1% of those of the laminar hook electrode. The cable electrode 0.5-1.0 mm in diameter consists of an electrically-conductive cord and an insulating dielectric sheath, and connected by the electrically-conductive cord to a surface stimulating the medullar structures.

EFFECT: using the invention provides both the posterior spinal fixation, and the epidural electric stimulation of the medullar structures simultaneously.

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Description

The invention relates to medicine, namely to traumatology and orthopedics, neurosurgery, and can be used to treat spinal disorders - vertebral myelopathies.

Currently, it is known that the treatment of patients with the neuroorthopedic consequences of tuberculosis, osteomyelitis and spinal injury is primarily associated with surgical operations, the ultimate goal of which is decompression of the spinal cord and restoration of supporting function of the spine.

Decompression of the spinal cord is ineffective or has little effect in more than 40-58% of operated patients, especially in cases with progressive vertebrogenic post-traumatic myelopathy. This category of patients needs new approaches and methods of postoperative stimulation of activation of mechanisms for restoration of lost functions of the spinal cord.

A disadvantage of the known methods of surgical treatment is the fact that the decompressive part of the intervention provides only the possible appearance of restorative functional prerequisites for the spinal cord, while stabilization of the spinal column with various types of metal structures acts as the restoration of only support function, without solving the problems of treating the neurological consequences of compression of the structures of the spinal cord brain, namely progressive myelopathy and, as its manifestations disabling, is expressed spinal disorders.

It is proved that the most complete stabilization of the spine is achieved by a combination of front and rear fixation of the spine.

One of the varieties of the posterior instrumental fixation of the spine is the use of a CD type construction consisting of laminar hooks and rods connecting them.

For postoperative treatment of vertebral spinal disorders - myelopathies, the method of epidural electrostimulation is used, which is usually associated with puncture or intraoperative implantation of cable electrodes on the dura mater [1].

It is known the use of multifunctional electrically conductive implants in anterior spinal fusion [5]. However, they do not provide an electrical stimulation effect on the posterior structures of the spinal cord, which is necessary to achieve the most complete clinical positive effect of treatment.

For instrumental fixation of the spine, a CD construction made of titanium alloy is used, characterized in that in order to increase the efficiency of surgical posterior stabilization of the spinal column, sub- and supralaminar implantation of laminar hooks rigidly fixed with titanium rods using screws is used [2, 3, 4]. However, the therapeutic potentialities of elements of the CD construct in cases with vertebral spinal disorders have not been used and are not currently used in world practice. In particular, in the available literature there is no information indicating the use of a laminar hook at the same time for stabilization of the spine and electrostimulating or any other effects on the structures of the spinal cord, i.e. the existing functional potential of laminar hooks inserted into the posterior epidural space is not used to combine with the procedures of electrical stimulation in the affected area of the structures of the spinal cord.

Thus, the failure to use the potential capabilities of posterior fixation elements of the CD construct type in the treatment of vertebrogenic myelopathy significantly limits the effectiveness of surgical treatment of vertebral spinal disorders in general, being a serious drawback.

The objective of the invention is to develop a laminar hook-electrode, which provides both back fixation of the spine and treatment of vertebral spinal disorders - myelopathy by epidural electrical stimulation of the structures of the spinal cord.

The problem is solved due to the fact that for the complex treatment a laminar hook is used, the fixing curved hook-shaped part of which is made in the form of a monolithic base with the possibility of introducing during the operation under the arches of the vertebrae into the posterior epidural space, inside which an electrically conductive surface is formed to stimulate the structure of the spinal cord, delimited from the bulk of the hook-electrode with a dielectric gasket and having at least one blind hole for fixing the cable-electrode, while the volume of the electrically conductive surface surrounded by the dielectric gasket is 0.5-1% of the volume of the laminar hook electrode, and the cable electrode with a diameter of 0.5-1.0 mm consists of an electrically conductive core and an insulating dielectric sheath and is connected by an electrically conductive core with a stimulating structure spinal cord surface.

The device is illustrated by drawings in FIG. 1, 2, 3 and 4.

FIG. 1 is a view of a laminar electrode hook in 3 projections indicating the average dimensions of the individual parts in mm and a 3: 1 scale.

A is a bottom view of the working active fixing part of the laminar hook inserted into the posterior epidural space under the arc of the vertebra.

3 - electrically conductive surface in contact with the dura mater of the spinal cord.

2 - non-conductive insulating part surrounding the electro-stimulating surface of the hook.

B-B - side view of the active fixing part of the laminar hook-electrode, 2 - insulating, 3 - electrically conductive surface.

BB - view of the lateral section of the laminar hook-electrode assembly.

1 - the body of the hook electrode:

- along arrows B — section of the fixing part;

- along arrow A - the active stimulating surface adjacent to the dura mater with: 2 - a non-conductive insulating part surrounding the stimulating surface of the hook inside the titanium working fixing, 3 - an electrically conductive surface connecting to the cable electrode, which consists of: 5 - an insulating shell, 4 - conductive core of the cable electrode;

- on the back surface of the laminar hook - view along arrows B - the surface of the laminar hook electrode in the front projection.

FIG. 2 is a sectional view of an electrode hook:

1 - hook body;

2 - non-conductive insulating part surrounding the conductive surface of the hook inside the titanium working fixing;

3 - conductive surface of the hook-electrode;

4 - conductive core of the cable electrode;

5 - insulating sheath of the cable electrode.

FIG. 3 is a view of the ratios of the installed hooks-electrodes relative to:

6 - an arch of a vertebra;

7 - spinal cord;

8 - the core of the CD design.

Figure 4 - intraoperative view of the CD instrumental assembly, fixing the lumbar spine of the patient with two hooks-electrodes:

1 - hook-electrode inserted into the posterior epidural space supralaminar;

4-5 - cable electrode;

8 - fixing CD design rod.

The device is used as follows.

The laminar hook for CD fixation and epidural electrical stimulation of the structures of the spinal cord is brought into operation in the following sequence.

After skeletonization of the vertebral arches at the necessary levels, they are prepared - the inter-fissures expand, the yellow ligament is mobilized. Simulation of the laminar hook-electrode. For this, a cable electrode of an arbitrary required length, bare from the insulating sheath, is installed in the hole in the electrically conductive surface of the working stabilizing part of the hook. The hook-electrode is inserted epidurally sub- or supralaminar, depending on the clinical task, is rigidly fixed to the titanium rod by a screw to the body of the hook.

Separately, by perforation of the skin, the end of the cable electrode is displayed on the surface of the skin and is fixed with an atraumatic thread. The surgical wound is sutured in layers.

For epidural electrical stimulation, 2 laminar electrode hooks are used above (at the level) and (or) below the affected segments of the spinal cord.

At the end of the course of treatment, the cable electrodes are removed almost painlessly for the patient in the dressing room by pulling from the tissues for cutaneous leads.

After removal of the electrodes, laminar hooks acquire an independent function, remaining the supporting stabilizing structure of the CD stabilization system.

Clinical example.

Patient P., born in 1979, was hospitalized in the spine surgery department of the Federal State Budgetary Institution St. Petersburg Research Institute of Phthisiopulmonology of the Ministry of Health of Russia on March 15, 12 with complaints of pain in the thoracolumbar spine with radiation to the lower extremities, general weakness, lack of voluntary movements in the lower extremities, dysfunctions of the pelvic organs, lack of ability to sit and walk. Diagnosis: Generalized tuberculosis: Focal tuberculosis of the apices of both lungs. Tuberculous spondylitis Th10-L2, instability of the spine, leaky abscesses, gross compression of the spinal cord, lower spastic paraplegia, impaired pelvic organs (Fraenkel type AB).

The presence of common tuberculous spondylitis, neurological complications was an indication for multistage surgical treatment: on 11/11/12 and 06/28/12, radical reconstructive operations were performed in the amount of: Abscessotomy of the Th9-L1 vertebral body resection. Decompression of the spinal cord, removal of epidural abscess. Implantation of electrodes on the front surface of the TMT. Mesh anterior fusion with 2 fragments of an auto rib. Psoas abscessotomy on the right. Audit of retroperitoneal space.

The absence of significant neurological positive dynamics and residual instability of the spinal column served as an indication for the 3rd stage of surgical treatment. September 20, 12, the back instrumental CD fixation of the spine was performed at the level of the Th7-L2 vertebrae using Medtronic Sofamour Danec hooks and the laminar electrode hooks we proposed for subsequent epidural electrical stimulation (Figure 4).

On the control x-ray of the thoracolumbar spine from 09/14/12: The position of the implant is correct, the same. The hooks of the posterior instrumental fixation are attached supralaminarly to the arches of Th7, L1 on both sides, sublaminarly to the arches of Th8, L2 of the vertebrae. The position of the structure is correct. The shadows of the cable electrodes are determined.

The postoperative period was uneventful. Using the laminar electrode hooks we proposed, we conducted a course of epidural electrical stimulation of the spinal cord and its roots with frequencies in the range of 1-67 Hz.

After 2 months, the patient got to his feet, began to independently move along the corridor with the help of orthopedic walkers. The functions of the bladder and intestines were restored.

As a result, a regression of neurological symptoms from type A to type D was achieved on the Frankel scale. Cable electrodes removed from laminar hooks. The patient was discharged to continue rehabilitation therapy at the place of residence.

Thus, laminar electrode hooks effectively performed 2 functions: one - stabilization of the spine, the second - simultaneous electrical stimulation of the spinal cord and its roots, providing treatment for myelopathy - vertebral spinal disorders.

Literature

1. Pat. 2145242. Epidural electrode / Makarovsky A.N., Garbuz A.E., Gerasimenko Yu.P.

2. Pat. 2271165. A method of instrumental fixation of the lumbosacral spine in inflammatory diseases of the spine / Mushkin A.Yu., Garbuz A.E., Kuklin D.V., Evseev V.A.

3. Moon M.S. et al. Posterior instrumentation and anterior interbody fusion for tuberculous kyphosis of dorsal and lumbar spines // Spine. - 1995. - No. 17. - P. 1910-1916.

4. Agazzi S., Reverdin A., May D. Posterior lumbar interbody fusion with cages: an independent review of 71 cases // J. Neurosurg. Spine - 1999. - Vol. 91. - P.186-192.

5. Pat. 2153864. A multifunctional implant with shape memory for the surgical treatment of the consequences of tuberculous spondylitis / Makarovsky AN, Garbuz AE, Gerasimenko Yu.P. (prototype).

Claims (3)

1. Laminar hook-electrode for posterior fixation of the spine and epidural electrostimulation of the structures of the spinal cord, including the body of the hook and the curved hook-shaped fixing part, characterized in that the fixing curved hook-shaped part is made in the form of a monolithic base with the possibility of insertion under the arc of the vertebrae during the operation into the posterior epidural space, inside which an electrically conductive surface is formed to stimulate the structure of the spinal cord, delimited from the main mass of the hook-elec kind dielectric strip and having at least one blind hole for fixing an electrode cable. 2. The laminar electrode hook according to claim 1, characterized in that the volume of the electrically conductive surface surrounded by the dielectric gasket is 0.5-1% of the volume of the laminar electrode hook. 3. The laminar electrode hook according to claim 1, characterized in that the cable electrode with a diameter of 0.5-1.0 mm consists of an electrical conductive core and an insulating dielectric sheath and is connected to an electrical conductive core with a stimulating structure of the spinal cord surface.

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