The case details and the results of treatment of 34 dogs with thoracolumbar intervertebral disc disease, without deep pain perception, that had been treated by laminectomy and fenestration, are presented. The association of a number of potential prognostic factors with the neurological outcome is examined. Twenty-one dogs (62 per cent) recovered neurological function, seven (21 per cent) failed to recover neurological function and three (9 per cent) developed progressive myelomalacia postoperatively, while three dogs (9 per cent) were euthanased intraoperatively because of diffuse myelomalacia. Twenty of the dogs that recovered neurological function showed a return of deep pain perception within two weeks of decompressive surgery. Statistical analysis showed significant differences in the outcome between dogs that took less than one hour to lose the ability to ambulate and dogs with a longer duration of onset of inability to ambulate. The extent of spinal cord swelling determined by myelography was not found to be a useful prognostic indicator.