Preoperative increase in neuromuscular jitter and outcome following surgery for faecal incontinence.

Background: Long-term results of surgery for faecal incontinence remain disappointing. Previous studies have demonstrated that pudendal neuropathy may progress in incontinent patients managed either conservatively or operatively. This progression of pudendal neuropathy may underlie poor long-term results.

Methods: Measurement of neuromuscular jitter by single-fibre electromyography allows the stability of terminal motor axons and end-plates to be assessed before operation. An increase in jitter implies progressive denervation.

Results: In this study, patients with increased jitter before operation (n = 14) had significantly worse symptom scores (median (interquartile range (i.q.r)) 14 (9-18) versus 3 (2-8), P = 0.007) and lower squeeze pressures (median (i.q.r.) 23 (21-36) versus 53 (46-60) mmHg, P = 0.015) at 6-month follow-up compared with those with normal jitter before operation (n = 22).

Conclusion: This study implies that the poor results of surgery are related to progressive denervation and that this may be assessed before operation.