[Laser ablation of intervertebral disc: animal experiment].

The lumbar intervertebral discs (L3-6) were ablated through a transperitoneal approach in 12 adult dogs by using Nd: YAG laser (1.06 microns) with a 600 microns quartz fiber. The status of limbs motion and sphincter (bladder, bowel) was observed for evaluating the safety of laser irradiation. After irradiation, the animals were sacrificed at prescribed intervals of up to 40 weeks (2, 4, 8, 12 and 40 weeks after operation). The lumbar intervertebral discs were harvested and subjected to light microscopic observation. No dog had suffered from neurogenic dysfunction of limb motion and sphincter. Histological findings immediately after the irradiation showed the disc was vaporized and a cavity was made. After 2 and 4 weeks, fibrous tissues began to proliferate, but cartilaginous tissues replaced the fibrous tissues 12 weeks after the laser irradiation. No new bone formation was found within 40 weeks after operation. On the basis of this study and our previous cadaveric study, percutaneous laser disc decompression (PLDD) was applied in clinical practice in march of 1993. 10 patients underwent PLDD utilizing the same laser equipment. The average follow-up was 3 months. According to the Macnab's criteria, there was an excellent response in 7 patients and a good response in 3.

Cervical spondylotic myelopathy treated by anterior multilevel decompression and fusion. Follow-up report of 214 cases.

From 1974 to 1982, 214 patients were treated for cervical spondylotic myelopathy by anterior multilevel decompression and the Robinson anterior interbody fusion and followed for an average of three years and 11 months. Postoperative results were superior to those obtained previously using posterior decompression. The average patient age was 50.1 years (range, 30-75); there were 187 men and 27 women. Overall, the percent of patients with excellent and good results was 59.3%; with fair results, 29%, no change; 7.9%, and deterioration, 3.8%. Of the 111 patients who had the disease less than one year before treatment, 74% were categorized after surgery as excellent or good. In contrast, only 36% of the 66 patients who had the disease more than two years were rated excellent and good. Myelography is valuable in diagnosing and locating lesions. The average number of discs removed was 3.1 per patient. The number of cases with excellent and good results was the same whether or not union of the graft occurred. Reoperation was required in 12 patients, and a third operation was performed in three patients. Eventually, 93% of the patients were able to lead independent lives.