1603 - Caught in the Groove: Bilateral Radial Nerve Entrapment Masquerading as Polyneuropathy

Friday, February 20, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

KF

Kris Foley, MD

Resident
Mount Sinai Hospital
New York, New York, United States

Co-Author(s)

SN

Subhadra Nori, MD

Attending
NYCHHC Elmhurst
Elmlhurst, New York, United States

Submitter(s)

KF

Kris Foley, MD

Mount Sinai Hospital
New York, New York, United States

Case Diagnosis: Bilateral radial neuropathy with compression at the spiral groove in the setting of alcohol-related polyneuropathy.

Case Description: A 52-year-old male with a history of alcohol use disorder (AUD) was admitted for alcohol withdrawal. He reported progressive bilateral wrist weakness, right wrist weakness for 6 months, left wrist weakness for 2 months. On exam, he demonstrated severe bilateral wrist drop (0/5 wrist extension), weakness in finger flexion and abduction, and atrophy of the intrinsic hand and forearm muscles. NCS demonstrated severe bilateral sensorimotor axonal and demyelinating radial neuropathy at the spiral groove. EMG revealed abnormal electrical activity (PSW, Fibs, late recruitment, incomplete interference pattern) and no viable motor units in all radially innervated muscles distal to the triceps bilaterally. Triceps and non-radial muscles had normal electrical activity. NCS of the bilateral median and ulnar nerves demonstrated prolonged distal and peak latencies, but normal conduction velocities. Findings were consistent with severe bilateral sensorimotor axonal and demyelinating radial neuropathies at the spiral groove, superimposed on a generalized alcohol-related sensorimotor polyneuropathy.

Discussions: Radial neuropathy at the spiral groove is most often due to compression by humerus fracture, though can also occur from external pressures. Bilateral involvement is rare and suggests systemic predispositions such as metabolic or toxic neuropathies. In this patient, chronic alcohol use likely contributed to a baseline polyneuropathy. Although he had no trauma to the upper arms, his history of frequent heavy alcohol intoxications increased susceptibility to external compression secondary to poor sleeping positions, leading to compression of the radial nerves at the spiral grooves on separate occasions. The EMG findings were crucial in distinguishing focal radial entrapments from diffuse neuropathy or central causes.

Conclusions:

This case highlights the role of EMG in differentiating focal mononeuropathies from systemic neuropathic processes in AUD. Identifying superimposed compressive neuropathies is essential for targeted rehabilitation, counseling, and prevention of recurrence.