[PUBLICATION] Median nerve entrapment syndrome in the elbow and proximal forearm. Anatomic causes and results for a 55-case surgical series at a mean 7 years' follow-up

Abstract

Background: Proximal median nerve (MN) neuropathy represents 1% of upper-limb compressive neuropathies. The literature reports two clinical presentations, depending on the location of the entrapment: pronator teres (PT), and anterior interosseous nerve (AIN) syndrome.

Hypothesis: There is no correlation between symptoms and location of proximal compressive structures on the MN trunk or AIN.

Patients and methods: Clinical and paraclinical data from 55 surgical MN releases around the elbow and proximal forearm were analyzed retrospectively. Mean age at diagnosis was 56±15years. Preoperative sensory and motor deficit signs were present in 89% of cases. Reduced MN conduction velocity and/or neurogenic anomalies in the MN territory were present in 94% of cases. Intraoperative details of compressive structures were collected. Patients were followed up in consultation to assess progression of symptoms and deficits.

Results: Mean follow-up was 84±70months. Objective motor deficit signs persisted in 18 of the 35 patients (18 cases), and objective sensory signs in 19 cases. A compressive anatomical structure was systematically found. There were at least two MN entrapment sites in 13 cases (24%). No isolated AIN entrapment was found. There was a significant correlation between symptom duration and persistence of objective sensory signs (p=0.002).

Discussion: There was no correlation between entrapment site and clinical signs on examination. Surgery requires exploring all potential entrapment sites. Improvement may be incomplete in case of late treatment.

Level of evidence: IV; retrospective study.

Keywords

Anterior interosseous nerve; Anterior interosseous nerve syndrome; Compressive neuropathy; Median nerve; Pronator teres syndrome.