Outcomes of Corticosteroid Injection for Lacertus Syndrome

Lacertus syndrome is a proximal median nerve compression neuropathy characterized by weakness of flexor pollicis longus (FPL), index finger flexor digitorum profundus (FDP), and flexor carpi radialis (FCR) and pain with compression of the median nerve at the lacertus fibrosus. The purpose of this study was to investigate the efficacy of corticosteroid injection (CSI) for symptom management in lacertus syndrome.

A retrospective review of patients with lacertus syndrome who underwent lacertus CSI between 2016 and 2021 was performed. Patient demographics, history, and physical examination were extracted from the electronic medical record. Outcomes included subjective improvement in symptoms, physical examination findings, incidence of repeat lacertus CSI, and/or subsequent surgical lacertus fibrosus release.

A total of 64 patients met the inclusion criteria. Chief complaint included hand/forearm pain in 44 patients (69%), median nerve paresthesias in 49 patients (77%), and hand weakness in 9 patients (14%). On examination, 63 (98%) had tenderness at the lacertus fibrosus. Manual motor testing identified weakness of the index FDP in 50 patients, FPL weakness in 42 patients, and FCR weakness in 23 patients. Forty-eight (75%) patients had subjective improvement in symptoms following CSI. Seventeen patients who had an initial response to CSI subsequently underwent surgical lacertus release, with 16 of 17 surgical patients reporting postoperative symptom relief.

Seventy-five percent of patients with lacertus syndrome who underwent CSI at the lacertus fibrosus experienced at least temporary subjective symptomatic relief. Of the 35% of patients who had recurrent symptoms after CSI and underwent surgery, the vast majority experienced symptom relief.