Influence of Preoperative Nerve Conduction Studies on the Outcome of Carpal Tunnel Release Surgery

Nerve conduction study (NCS) is the most common investigative tool used in diagnosing and determining the severity of carpal tunnel syndrome (CTS). We aimed to evaluate the relationship between preoperative NCS and the outcome of patients who underwent carpal tunnel release (CTR). Medical records of patients who underwent CTR from January 2018 to December 2023 were reviewed retrospectively. Demographic, clinical characteristics and NCS reports were extracted. CTS severity was graded according to the Canterbury criteria. The outcome was defined as improved or not improved based on subjective symptoms at 2 months post-surgery. A total of 283 CTR cases were identified, with a mean patients age of 58.0±15.1 years and predominantly females (n=189, 75.0%). The main risk factors were obesity (34.6%) and diabetes mellitus (27.0%). Surgeries were performed on the right hand in 60.4% of cases. The mean duration of symptoms and the interval between NCS and surgery were 16.4±21.6 months and 10.1±13.4 months, respectively. Of the 201 reports of NCS, the majority had very severe CTS (25.4%), followed by mild (20.4%), moderate (18.9%), severe (17.4%), extremely severe (11.4%), normal (6.0%) and very mild (0.5%). From multivariate analysis, younger age (OR 0.95; 95% CI 0.91-0.99; p=0.024), more items of preoperative history and physical examination (OR 1.58; 95% CI 1.01-2.47; p=0.045) and preoperative NCS severity (p=0.006) were associated with improved outcomes. In addition to known prognostic factors, the utilization of NCS before CTR is crucial as the severity of preoperative NCS can be a predictor of postoperative outcomes.