OMS-IV UNTHSC-TCOM Fort Worth, Texas, United States
Case Diagnosis: Median Nerve Entrapment at the Ligament of Struthers
Case Description: Patient with prior history of bilateral carpal tunnel release presented with pain, numbness, and tingling from the right elbow to thumb five weeks after lifting a heavy object. Patient had weakness in wrist pronation and flexor pollicis longus activation. Initial electrodiagnostic studies showed median neuropathy across the right wrist and appeared to be a recurrence of carpal tunnel syndrome. However, after three weeks the patient returned with worsening symptoms. Repeat electrodiagnostics revealed new fibrillations and sharp waves with needle evaluation of the right pronator teres and flexor digitorum profundus of the second digit, reflecting a more proximal lesion and raising concerns for median nerve entrapment under the Ligament of Struthers (LS).
Discussions: The LS is a structure that originates from a supracondylar process and inserts into the medial condyle of the humerus. Both the median nerve and brachial artery pass under here creating a potential source of compression. This can lead to paresthesias and numbness of the hand and forearm, also known as supracondylar process syndrome. Overall this process is rare due to the prevalence of the LS being 0.1% and 2.7% in the human population. Electromyography, ultrasonography, and MRI can help confirm clinical findings. In symptomatic cases, conservative measures were often insufficient and most surgical interventions were curative.
Conclusions: Entrapment of the median nerve under the LS is a rare process that can lead to supracondylar process syndrome that presents similarly to carpal tunnel syndrome in addition to symptoms in a more proximal distribution. Further evaluation with studies such as electromyography, ultrasonography, and MRI is warranted in such cases to rule out other causes of median nerve compression and guide further management. Subsequent referral to surgery for decompression of the entrapped nerve provides definitive treatment, as was the case here.