Patterns of nerve injury and recovery rates of infraclavicular brachial plexus lesions following anterior shoulder dislocation.

Abstract

Purpose: We reviewed our cases of infraclavicular brachial plexus injuries associated with anterior shoulder dislocation to determine patterns of injury, recovery rates, and factors associated with a poor motor outcome.

Methods: This was a retrospective review of patients who had sustained a concomitant nerve injury following dislocation of the glenohumeral joint treated with closed manipulation. The data collected included patient demographics, injury factors, and patterns of neurological deficits. The Medical Research Council (MRC) grade for motor power was the primary outcome measure, where a grade of 4 or 5 was regarded as achieving good motor recovery. Univariate and multivariable analyses were used to identify factors associated with persistent motor weakness (MRC grades 0-3) at the final follow-up.

Results: Between 2015 and 2019, 61 patients were assessed. There were 36 males and 25 females, with a median age of 64 years (interquartile range [IQR], 53-73 years). Four patterns of injury were identified: (1) isolated axillary nerve lesions; (2) single cord lesions; (3) combined lesions involving the medial and posterior cords; and (4) diffuse lesions affecting all 3 cords. Of 28 patients with isolated axillary nerve injuries, 22 recovered. All lateral cord injuries (11/11) and 20 of 24 posterior cord injuries recovered spontaneously. Recovery of hand intrinsic function from medial cord injuries had the worst outcome, with 14 of 27 patients not recovering beyond MRC grades 0 to 3. The median duration of dislocation before reduction was 6 hours (IQR, 3-12 hours). A multivariate analysis showed an association between the duration of shoulder dislocation and the likelihood of persistent motor weakness.

Conclusions: Shoulder dislocations with motor deficits should be regarded as orthopedic emergencies and reduced expediently. Persistent motor weakness may be associated with a prolonged duration of dislocation prior to glenohumeral relocation.

Type of study/level of evidence: Prognostic IV.