[Is high resolution ultrasound of the median nerve helpful before reintervention after failed carpal tunnel surgery?]

A common reason for persisting or new complaints after carpal tunnel surgery is an incomplete release of the retinaculum flexorum. Traction neuropathy, a real recurrent carpal tunnel syndrome and iatrogenic nerve lesions occur less frequently. In the case of an incomplete release of the flexor retinaculum the clinical symptoms in most of the patients can be resolved with revision surgery. Electrodiagnostic testing can only support the indication for a reoperation if a preoperative examination exists but is not able to demonstrate the exact cause of a failed carpal tunnel surgery. The 4 cases presented here show that high resolution ultrasound provides valuable information in addition to electrodiagnostic testing before a reintervention.