Background: Approximately 50-60% of paraplegic deep pain negative (DPN) dogs with thoracolumbar intervertebral disc extrusion (TL-IVDE) recover ambulation after surgery. F-wave duration has been associated with injury severity in TL-IVDE but the relationship to outcome is unknown.Hypothesis/
Objectives: Evaluate the prognostic utility of F-waves in DPN dogs with TL-IVDE. Animals: Nineteen client-owned dogs presented between 2021-2024.
Methods: Multi-center prospective, observational study. Acutely, paraplegic DPN dogs with TL-IVDE managed surgically were included. F-waves were performed within 24 hours post-operatively. F-wave parameters included persistence, minimum latency, duration, amplitude, conduction velocity, F ratio, F:M ratio and after-discharge activity (scored from 0/none to 3/severe). Outcome was categorized as successful or unsuccessful with success defined as recovery of pain perception and independent ambulation at 3-months post-operatively. Wilcoxon rank-sum test compared F-wave variables between dogs with a successful or unsuccessful outcome.
Results: Twelve dogs had a successful outcome and 11 dogs were unsuccessful; 7 dogs were removed from analysis. In dogs with unsuccessful outcomes compared to those with successful outcomes (data displayed as median (range)), mean F-wave duration was longer (30.9 ms (11.4-60.8) vs 15.0 ms (9.5-25.3), p = 0.0097), maximum F-wave amplitude was larger (1340 µV (400-2380) vs 590 µV (330-1400), p = 0.019), and after-discharge activity score was higher (2.7 (0.1-3.0) vs 1.4 (0-2.5), p = 0.024). Conclusions and clinical importance: F-waves could aid in predicting outcome in DPN dogs with TL-IVDE treated surgically.
