Can the outcome of open carpal tunnel release be predicted?: a review of the literature.

Carpal tunnel syndrome is a common condition affecting 1% of the population. Open carpal tunnel release is the most commonly performed procedure for this condition. About 70-90% of patients have good to excellent long-term outcomes with open carpal tunnel release. The remainder have poor outcomes. An understanding of factors which predict a poor outcome following open carpal tunnel release would be of benefit during preoperative counselling, and provides more accurate expectations of outcomes after surgery. We reviewed the published literature in the English language over the last 20 years in an attempt to ascertain predictors of poor outcomes following open carpal tunnel release. Patient factors such as age, sex and weight were not found to be predictors of a poor outcome following open carpal tunnel release. Similarly, physical examination had little usefulness, save for abductor pollicis wasting, for predicting post-surgical functional limitations, symptoms or satisfaction. Co-morbid conditions such as diabetes, poor health status, thoracic outlet syndrome, double crush, alcohol and smoking have a worse prognosis. Normal nerve conduction studies preoperatively, direct nerve surgery such as neurolysis, abductor pollicis brevis muscle wasting and workers' compensation cases which involve lawyers preoperatively are all associated with worse outcomes. Postoperative physiotherapy may accelerate recovery but neither modifies functional recovery or reduces symptom occurrence.