Predictors of surgical outcomes after in situ ulnar nerve decompression for cubital tunnel syndrome

Background In the treatment of cubital tunnel syndrome (CuTS), in situ ulnar nerve decompression is commonly used. This study aims to investigate predictive factors for poor recovery and ulnar nerve instability following this procedure. Methods We enrolled 235 patients who underwent in situ ulnar nerve decompression for the treatment of CuTS from January 2010 to December 2014. All patients underwent >2 years' follow-up. The primary outcome was postoperative recovery, which was assessed by Messina's criteria, and the secondary outcome was postoperative ulnar nerve instability. Potential risk factors were collected from demographic data and electrodiagnostic test, which included age, gender, body mass index, history of tobacco or alcohol use, history of major medical comorbidities, disease duration, preoperative severity, motor conduction velocity, and sensory conduction velocity. Results A total of 208 patients (88.5%) had satisfactory outcomes, while the other 27 patients (11.5%) had not. There were 25 patients (10.6%) showing postoperative ulnar nerve instability during follow-up. The multivariate analysis showed that only severe preoperative symptom (odds ratio [OR], 3.06; 95% confidence interval [CI], 2.16-4.32) was associated with unsatisfactory postoperative outcomes in patients with CuTS (P<0.001). In the model investigating independent factors associated with postoperative ulnar nerve instability, we found that young age (OR, 2.41; 95% CI, 1.63-3.58) was associated with the incidence of postoperative ulnar nerve instability (P<0.001). Conclusion We found that severe preoperative symptom was associated with unsatisfactory postoperative outcomes, and young age was a risk factor for the incidence of postoperative ulnar nerve instability. Patients with these risk factors should be informed of the possibility of worse surgical outcomes.