Diagnosis, surgery, and outcome of tethered cord syndrome in 12 dogs.

Abstract

BACKGROUND: Tethered cord syndrome (TCS) results from tension on the conus medullaris (CM), causing pain, bladder or bowel dysfunction, and lower limb neurologic deficits in humans. It is underrecognized in dogs; diagnosis is difficult and depends on improvement after surgery. HYPOTHESIS/OBJECTIVES: Describe clinical signs, advanced imaging results, surgical procedures, and outcomes of dogs with TCS. Develop objective measurements of CM and dural sac (DS) movement on dynamic magnetic resonance imaging (MRI) in dogs that benefitted from TCS surgery. ANIMALS: Twelve client-owned dogs that underwent TCS surgery with follow-up. METHODS: Retrospective study. Diagnosis was based on clinical signs and MRI or computed tomography (CT). The MRI measurements were performed retrospectively in extension and flexion. RESULTS: Median age at presentation was 52 months (range, 1-12 years). All the dogs had lumbar pain and transient paresthesias such as biting at their hindquarters, sitting urgently or looking at their hindquarters. Dynamic imaging identified minimal craniocaudal movement of the DS and CM between flexion and extension. The mean movement of the CM and DS was 0 mm (range, -1.79 to -2.6 mm), and 0.93 mm (range, -1.4 to -2.9 mm), respectively. All the dogs had a taut external or internal filum terminale, extradural adhesions, or both, which were transected during surgery. All the dogs showed improvement at short-term and long-term follow-up. CONCLUSIONS AND CLINICAL IMPORTANCE: Dogs with unexplained lumbar pain and transient paresthesias should be evaluated using dynamic MRI. If minimal movement of the DS or CM is noted, surgical detethering is indicated.