Reawakening Neuritis of the Median Nerve after Carpal Tunnel Release: Defining and Predicting Patients at Risk

Patients with long-standing carpal tunnel symptoms may develop transient and, paradoxically, worsened neuropathic pain immediately following release. The authors have termed this "reawakening phenomenon." The purpose of this study was to compare the characteristics of patients with this phenomenon to those with a standard postoperative course.

A retrospective chart review was performed on all patients who underwent carpal tunnel release at a single institution between January of 2012 to December of 2017. Patients demonstrating increased neuropathic pain in the median nerve distribution postoperatively without evidence of complex regional pain syndrome were included. A comparison cohort was composed of the remaining patients identified. Demographic data, medical history, carpal tunnel history, and electromyogram and nerve conduction study findings were recorded.

A total of 640 patients were identified; 440 met criteria. Seventeen patients were found to have symptoms consistent with median nerve reawakening phenomenon. The reawakening cohort was older (71.1 versus 56.8 years), more likely to have evidence of thenar muscle atrophy (58.8 percent versus 13.48 percent), and more likely to have fibrillations and sharp waves on electrodiagnostic studies. Although not statistically significant, they also had a longer duration of symptoms (4.9 versus 2.9 years). Of those patients with reawakening phenomenon, 14 had resolution of their symptoms at an average period of 4.4 months. Three remaining patients who were subjectively symptomatic had normal or improved postoperative electromyogram and nerve conduction studies.

Reawakening of the median nerve has not been previously described but occurs in 3.9 percent of hands following routine carpal tunnel release. Preoperative counseling of patients at high risk for reawakening phenomenon is recommended.

Risk, III.