Hernias of Intervertebral Discs of Various Spine Segments: Transcutaneous Laser Vaporization

A.Yu. Vasilyev, V.M. Kaznacheev, B.V. Fomin, G.A. Pakhomov, I.V. Luppova, T.M. Shumailova

Chief Clinical Hopsital of the Russian Ministry of Internal Affairs,
Chair of Neurosurgery of the Moscow State Medical-Stomatologic University, Moscow, Russia

 

The goal of the present study was to determine optimum parameters of laser irradiation and to estimate results of treatment in patients with hernias of the cervical, thoracic and lumbar spine.

Materials and Methods. The first stage consisted in laser irradiation of 8 (cervical), 5 (thoracic) and 10 (lumbar) explanted human disks of 12 cadavers. Irradiation was carried out with the Dornier Medilas Fiberton 5060/5100 neodymium YAG laser with a wavelength of 1060 nm. The experiment resulted in determining of those parameters of laser irradiation for discs of all spinal segments, which led to reduction of dimensions of a pulpous nucleus due to vaporization of its fluid constituent. Absence of damage of a disk morphologic structure was confirmed by histological examination.

We used puncture laser irradiation in 247 cases. Interventions were performed on the lumbar spine (184 patients), thoracic spine (18 cases) and cervical spine (45 cases). A mean age of patients was 42.7±5.9 years. Disease duration varied from3 months up to 10 years.

Puncture laser vaporization was performed under local anesthesia and control of the Picker Q-2000 computer tomograph with the Karl Storz needle (a diameter of 0.8 mm). Lumbar and thoracic discs were punctured with applying a posterolateral approach. An anterolateral approach was used in manipulations on the cervical spine. A level, corresponding to a middle part of the impaired disk, was marked after CT scanning. It was followed by a puncture of a pulpous nucleus; we strived for placing the needle tip at a distance of not less than 7 mm from a fibrous capsule (a good-effect zone of the neodymium laser). A light guide was inserted through the needle lumen 1 mm farther than its tip. Vaporization was carried out, using a standard pulse mode + LPS (a mode, preventing carbonization of a light guide tip). A pulse duration, an interval between pulses and current intensity were equal to 1 sec, 1 sec and 15 W respectively.

Patients with lesions of the cervical spine were in a supine position with a pad under their neck. An impaired disk was punctured along a medial edge of the right sternomastoid muscle under the control of CT; a neurovascular bundle was displaced laterally with the help of index and middle fingers. In contrast to operations on the lumbar or thoracic spine, a vector of laser irradiation spread was directed to the spinal cord in interventions at a cervical level. Thus, any doubt, concerning correct location of the needle tip, resulted in additional CT scanning. In case of necessity, the needle was put in an optimum position. As for cervical discs, pulse duration, an interval between pulses and current intensity were 1 sec, 2 sec and 10 W respectively.

Total energy, determined during intervention, was individual for each patient. It was conditioned by patient's complaints, a character of discharge from the puncture needle cannula and data of in vitro experiment. Its average value was 900-1500 J (lumbar spine), 600-900 J (thoracic spine) and 350-500 (cervical spine).

Patients, wearing a semi-rigid corset, were allowed to walk within the limits of a ward in 3-4 hours after operation. Anti-edematous (I/M dexazon in a dose of 8mg 2 times a day) and desensitizing (suprastin, pipolfen, etc.) therapy was carried out during 3 days. Medical gymnastics, aimed at eliminating static disorders, restoring a volume of motion and strengthening of muscles, started on the 2nd day. If a course of a postoperative period was favorable, patients were discharged for further out-patient treatment. They were recommended to continue a course of medical gymnastics and to wear a corset in physical load during 2-3 months.

Results. The analysis demonstrated, that decrease or disappearance of radicular pain syndrome was watched in 82.2% of patients immediately after intervention. Estimation of tension symptoms was indicative of increased volume of motion (by 15-30o) in 80.9% of cases. Control MRI-examination, carried out 2 months after vaporization at a lumbar level, showed decrease of hernia protrusion, which made 50% of initial dimensions in 67 out of 184 patients; hernia was absent in 5.7% of cases. No change of hernia dimensions was observed in 27 patients; however, there was regression of pain syndrome with preservations of such minor manifestations, as hypesthesia and hyporeflexes. Hernia protrusion at a cervical level reduced by 50% in 14 out of 45 cases. As for the thoracic spine, hernia dimensions remained unchanged in all cases, but there was a positive clinical effect.

Conclusion. Transcutaneous laser vaporization of degenerated discs can become one of the effective, low-invasive methods of treatment of hernias, located in all spinal segments. It allows to reduce treatment cost and duration of a rehabilitation period.