Lumbosacral intervertebral disk extrusions in 13 dogs

Objective To describe the clinical presentation, magnetic resonance imaging (MRI) findings, and outcome of dogs treated surgically for lumbosacral intervertebral disk extrusion (IVDE). Study design Retrospective study. Animals Thirteen dogs. Methods Records and MRI studies of dogs with intraoperatively confirmed lumbosacral IVDE were reviewed. MRI features of thoracolumbar IVDE were applied to all cases. Postoperative outcome was subjectively assessed as excellent, good, or poor. Results All dogs had an acute or subacute onset of lumbosacral pain and nerve root signature. Seven dogs had neurological deficits. MRI revealed lateralized herniated disk material and partial to complete disk degeneration in all cases; the extradural material extended cranial and/or caudally from the disk space in 10 cases. All dogs underwent L7-S1 dorsal laminectomy and removal of extruded disk material. In six dogs, surgery was complicated by inflammatory changes, including one case of epidural steatitis. On reexamination 4-6 weeks postsurgery, outcome was judged as excellent in 11 dogs and poor in the remaining 2 due to contralateral nerve root signature in one case and nonambulatory paraparesis and urinary incontinence in the case with steatitis. Conclusion Lumbosacral IVDE in dogs was characterized by acute/subacute onset of lumbosacral pain and nerve root signature and lateralized and often dispersed extradural material over a degenerated L7-S1 intervertebral disk on MRI. Early decompressive dorsal laminectomy generally resulted in excellent clinical outcome. Clinical significance Observation of these clinical and imaging features in dogs should prompt clinical suspicion of lumbosacral IVDE.