Traumatic and iatrogenic sciatic nerve injury in 38 dogs and 10 cats: Clinical and electrodiagnostic findings

Abstract

Background: Reports describing sciatic nerve injuries (SNI) and their outcome are scarce in veterinary medicine. Hypothesis: Describe the causes of traumatic and iatrogenic SNI and evaluate which clinical and electrodiagnostic findings predict outcome. Animals: Thirty-eight dogs and 10 cats with confirmed SNI referred for neurologic and electrodiagnostic evaluation. Methods: Clinical and electrodiagnostic examination results, including electromyography (EMG), motor nerve conduction studies, muscle-evoked potential (MEP), F-waves, sensory nerve conduction studies, and cord dorsum potential (CDP), were retrospectively evaluated. Quality of life (QoL) was assessed based on owner interviews. Results: Surgery (42%) and trauma (33%) were the most common causes of SNI; in dogs, 24% were caused by bites from wild boars. Ability to flex and extend the tarsus was significantly associated with positive outcome in dogs. Mean time from onset of clinical signs until electrodiagnostic evaluation was 67 ± 65 (range, 7-300) days and 65 ± 108 (range, 7-365) days for dogs and cats, respectively. A cut-off amplitude of 1.45 mV for compound motor action potentials (CMAP) was predictive of positive outcome in dogs (P =.01), with sensitivity of 58% and specificity of 100%. Conclusions and Clinical Importance: Clinical motor function predicts recovery better than sensory function. Electrodiagnostic findings also may play a role in predicting the outcome of SNI. Application of the proposed CMAP cut-off amplitude may assist clinicians in shortening the time to reassessment or for earlier suggestion of salvage procedures. Owners perceived a good quality of life (QoL), even in cases of hindlimb amputation.