# Elbow Flexion Recovery and Respiratory Function in Total Traumatic Brachial Plexus Injury Patients Treated with Phrenic Nerve Transfer

## TL;DR

This study examines how phrenic nerve transfer helps restore elbow movement and breathing in patients with severe brachial plexus injuries.

## Contribution

The study provides empirical evidence on elbow flexion recovery and respiratory outcomes following phrenic nerve transfer in traumatic brachial plexus injury patients.

## Key findings

- 37.5% of patients achieved MRC level III elbow flexion, and 43.8% reached level IV.
- Elbow flexion strength averaged 9.1% compared to the unaffected arm.
- No severe respiratory impairment was observed, and neuroplasticity enhanced arm motor control over time.

## Abstract

To evaluate the outcomes of phrenic nerve transfer in total traumatic brachial plexus injury, focusing on elbow flexion and respiratory function.

The present is a case series of 16 patients undergoing phrenic nerve transfer between 2014 and 2021. Patients over 18 years old, operated on for more than 6 months, and without other orthopedic conditions of the upper limb were included. Elbow flexion strength was assessed by Medical Research Council (MRC) scale and an isokinetic dynamometer, along with an electromyograph. Respiratory function was assessed by spirometry.

The patients were mainly young men affected by motorcycle accidents. Level III on the MRC was achieved by 37.5% of patients, with 43.8% reaching level IV. On average, elbow flexion strength was of 9.1% compared with that of the unaffected arm. The study identified inconsistent deficits in respiratory function, with no severe impairment in forced vital capacity and forced expiratory volume. Respiratory symptoms were not reported. Involuntary activation of the biceps brachii during forced respiratory cycles was observed, peaking after an initial recovery period.

Phrenic nerve transfer effectively restored elbow flexion in most patients. We found signs of neuroplasticity that enhanced the motor control of the arm over time. We found no evidence of severe pulmonary impairment in these patients.