Ultrasound Cross-Sectional Area of the Median Nerve Is Not a Predictor of Patient Reported Outcomes After Carpal Tunnel Release

Abstract

Background: The purpose of this study was to evaluate the relationship between cross sectional area (CSA) of the median nerve on ultrasound (US) with pre- and postoperative Boston Carpal Tunnel Questionnaire (BCTQ) scores. We hypothesize that there is a positive correlation between CSA and the ΔBCTQ after carpal tunnel release (CTR). Methods: This was a single center study. During a 6-year period (2014-2020), CSA of the median nerve on US and BCTQ scores were collected prospectively for patients presenting with the chief complaint of numbness and tingling in the upper extremity. Patients who underwent CTR and presented for their 6-week follow-up had repeat measurements of the CSA and BCTQ. These patients were included in this study. Patients were then divided into ultrasound positive (CSA ≥ 10) and ultrasound negative (CSA < 10) groups. These groups were compared on the basis of demographics, preoperative BCTQ scores, postoperative BCTQ scores, and 6-week ΔBCTQ score. Results: US-positive and-negative groups did not differ significantly in their preoperative BCTQ, postoperative BCTQ, or ΔBCTQ scores. Both groups did, however, experience significant improvement when comparing preoperative to postoperative BCTQ scores within their respective US group. Conclusion: Regardless of the preoperative CSA of the median nerve, patients who underwent CTR experienced a significant improvement in their BCTQ results. US-positive patients experienced no greater improvement than US-negative patients. These results would suggest that US is not a good predictor of subjective surgical outcome measures such as the BCTQ.