Clinical aspects of surgical treatment of thoracolumbar disc disease in dogs. A retrospective study of 300 cases.

The clinical records of 300 dogs with thoracolumbar disc disease treated by decompressive surgery at the Clinic of Surgery and Orthopedics at Universi ty of Veterinary and Pharmaceutical Sciences in Brno during a four year per iod(April 1994 through March 1998) were reviewed. The breed, age and sex pr edisposition, the frequency of disc extrusion at each intervertebral disc s pace in thoracolumbar region of spine, and the location of extruded disc ma terial relative to the spinal cord were recorded. The number of patients wi th multiple disc herniations was also recorded. Dogs were grouped by clinic al signs of disease into five groups (I, II, III, IVA NB and NC grades). Re covery rates depending on the preoperative neurological grade of spinal inj ury and duration of clinical signs were compared. Patients were observed at least 9 months after surgery. AU dogs were treated by hemilaminectomy with out prophylactic fenestration of other disc spaces. The results of treatmen t in ten dogs with grade II involvement were excellent in 80% of these dogs , very good in 10%, and fair in 10%. The results of treatment in 68 dogs wi th grade III involvement were excellent in 80.88% of these patients, very g ood in 8.82%, and fair in 10.29%. The results of treatment in 111 dogs with grade IV A involvement in which decompression was performed within 48 hour s of the onset of clinical signs were excellent in 71.17% of these patients , very good in 12.61%, fair in 14.42%, and poor in 1.80%. The results of tr eatment in 56 dogs with grade IV A involvement in which decompression was p erformed later than 48 hours after onset of paraplegia were excellent in 46 .43%, very good in 25.00%, fair in 17.87%, and poor in 10.70%. Hemilaminect omy was performed in thirty-one dogs with severe neurological dysfunction ( group IV B) within 48 hours after onset of paraplegia. Outcome of the surge ry was excellent in 22.58% of these patients, very good in 6.45%, fair in 4 8.39%, and poor in 22.58%. The results of treatment in 5 dogs with grade TV C involvement were excellent in 40% of these patients, and fair in 60%. Nineteen dogs died in the perioperative or early postoperative period and t hus were lost to follow-up. Recurrence of neurological deficits in the rema ining group of 281 clinical patients was assessed. The recurrence rate obse rved from 9 to 51 months after surgery, was 14.59% (41 cases). Fourteen dog s had a recurrence of paraparesis (grade II and III) and twenty-seven dogs had paraplegia (grade IV) 1 to 30 months (mean 10.27 +/- 7.25 months) after surgery. In all 41 cases cause of the recurrence was extrusion of other di sc.