SPINAL-CORD SWELLING AS A MYELOGRAPHIC INDICATOR OF PROGNOSIS - A RETROSPECTIVE STUDY IN DOGS WITH INTERVERTEBRAL DISC DISEASE AND LOSS OF DEEP PAIN PERCEPTION

The association of myelographic spinal cord swelling with neurological outcome was examined in 46 dogs with intervertebral disc disease and absence of deep pain perception (DPP). Spinal cord swelling was measur ed by calculating a ratio of the length of the loss of the myelographi c dye column to the length of the second lumbar vertebra (L2). A posit ive neurological outcome was defined as return of voluntary motor func tion. A cut-off value for swelling: L2 of 5.0 was established by the c reation of a receiver operator characteristic curve. Using a swelling: L2 ratio of 5.0 as a cutoff for indication of neurological recovery y ielded a sensitivity of 74% and a specificity of 61%. Overall neurolog ical recovery rate was 43%. Dogs with spinal cord swelling: L2 ratios less than 5.0 had a recovery rate of 61%, whereas dogs with a ratio gr eater than or equal to 5.0 had a recovery rate of 26%. Evaluation of t hese data by chi square analysis confirmed that a ratio less than 5.0 was associated with a positive outcome, and a ratio greater than or eq ual to 5.0 was associated with a negative outcome, (P < .05). Although other factors, such as duration of neurological signs, affect neurolo gical outcome in dogs with no DPP, evaluation of myelographic spinal c ord swelling can assist in establishing a prognosis. (C) 1996 by The A merican College of Veterinary Surgeons.