Predictors of Future Contralateral Carpal Tunnel Release at the Time of Unilateral Surgery

Purpose: We assessed factors at the time of unilateral carpal tunnel release (CTR) for carpal tunnel syndrome to create a prediction formula for future CTR. Methods: We retrospectively identified 1,013 patients who underwent CTR at a tertiary care referral center from July 2008 to June 2013. A multivariable logistic regression model was used to identify independent factors associated with future contralateral CTR. A prediction formula was created and its validity was assessed by calculating the C-statistic for model discrimination and the Hosmer-Lemeshow goodness-of-fit test and calibration slope for model calibration. We tested the external validity of our formula using a sample of 100 random patients who underwent CTR at a second tertiary care referral center from October 2004 to August 2016. Results: Contralateral carpal tunnel symptoms and preoperative contralateral electrodiagnostic study severity were associated with increased likelihood of contralateral CTR, whereas black race and chronic kidney disease were associated with decreased likelihood of contralateral CTR. We constructed a prediction formula for the probability of undergoing contralateral CTR at 5.5 years’ follow-up. Conclusions: The probability of future contralateral CTR may be useful in preoperative counseling for select patients who are reasonable candidates for unilateral, staged bilateral, or simultaneous bilateral CTR. Our prediction formula can be an adjunct tool for shared decision making but it does not replace the experienced clinician's judgment based on the patient's history, physical examination, and confirmatory testing. Type of study/level of evidence: Prognostic III.