Clinical Predictors of C5 Spinal Nerve Viability in Pan-Brachial Plexus Injuries.

Background: In pan-brachial plexus injury, distinguishing between preganglionic and postganglionic injuries is crucial to reconstructive planning. This study aimed to identify preoperative factors that would accurately predict a reconstructible C5 spinal nerve.

Methods: Patients with pan-brachial plexus injury from a single institution between 2001 and 2018 were reviewed. Patient demographics, clinical examination, diagnostic imaging, and electrodiagnostic results were recorded. C5 viability was determined based on supraclavicular exploration and intraoperative electrophysiologic testing. Univariate analysis identified significant factors for regression analysis. A multivariable parsimonious model was created using stepwise high-performance logistic regression.

Results: A total of 311 patients (mean age, 29.9 years; 46 women and 265 men; mean Injury Severity Score, 17.2) were included. A total of 134 patients (43%) had a viable C5 nerve, and 50 patients (12%) had a viable C6 nerve. Intact C5 spinal nerve on computed tomographic (CT) myelogram (OR, 5.4), positive Tinel test (OR, 2.6), muscle strength greater than or equal to 4 (according to the modified British Medical Research Council scale) for the rhomboid (OR, 1.3) or greater than or equal to 4 for the serratus anterior (OR, 1.4), and rhomboid needle electromyography (OR, 1.8) were predictive of having a viable C5 spinal nerve. The multivariable parsimonious stepwise model (area under the curve, 0.77) included four factors: positive Tinel test, intact C5 spinal nerve on CT myelogram, hemidiaphragmatic elevation, and midcervical paraspinal fibrillations.

Conclusions: In this cohort of pan-brachial plexus patients with major polytrauma, there was a 43% incidence of viable C5 spinal nerve. A positive Tinel test (OR, 2.1) and intact C5 spinal nerve on CT myelogram (OR, 4.9) predicted a viable C5 nerve. In contrast, hemidiaphragmatic elevation (OR, 3.1) and midcervical paraspinal fibrillations (OR, 2.92) predicted root avulsion.

Clinical Question/level Of Evidence: Risk, III.