DISCOGRAPHY AND EPIDUROGRAPHY FOR EVALUATION OF THE LUMBOSACRAL JUNCTION IN DOGS WITH CAUDA-EQUINA SYNDROME

Cauda equina syndrome in the dog is a common neurologic disorder cause d by compression of the spinal cord, nerve roots and spinal nerves cau dal to the fifth lumbar vertebra. This paper describes the clinical si gns, radiographic findings of discography and/or epidurography, and co mparison with surgery or necropsy of 21 dogs with cauda equina syndrom e. Discograms were performed by using a 20- or 22-gauge spinal needle introduced in a sagittal plane into the lumbosacral (LS) disc space un der fluoroscopic guidance. Epidurograms were performed following disco graphy by injecting contrast medium after repositioning the tip of the needle into the ventral epidural space at the level of the LS junctio n. Direct examination of the LS junction was performed in all dogs by surgical exploration and/or necropsy. On survey radiographs, the most common findings were spondylosis, malalignment of the sacrum to the la st lumbar vertebra, collapse of the LS disc space, stenosis of the ver tebral canal at the LS junction, and transitional vertebral segments. Discography was considered of diagnostic quality in 19/21 (90%) of the dogs, showing disc protrusion in 14/21 (67%). Epidurography was of di agnostic quality in 18/18 (100%) dogs, showing abnormal findings in 14 /18 (78%). No adverse reaction was noted to the radiographic procedure when dogs were allowed to recover from anesthesia before surgery. Bas ed on macroscopic findings, combination of survey radiographs and disc oepidurography was correctly positive in 16/18 dogs (89%). It is concl uded that discography associated with epidurography is a valuable proc edure for evaluation of the LS junction in the dog. A combination of b oth procedures reduces the possibility of technical artifacts by outli ning both sides of the compressive lesion, i.e., the disc and the epid ural space.