Ventilation and exercise performance after phrenic nerve and multiple intercostal nerve transfers for avulsed brachial plexus injury

Background: Diaphragmatic excursion, lung function, exercise performance, and clinical symptoms have not been previously described in patients after phrenic nerve transfer (PNT) and/or multiple intercostal nerve transfer (MIT) for the repair of avulsed brachial plexus injury (ABPI) to prevent functional musculoskeletal impairment in the shoulder. Setting: A university-based hospital. Methods: Dyspnea scores, chest ultrasonography to assess diaphragmatic excursion, and pulmonary function testing were performed to assess ventilation in patients sustaining trauma to their brachial plexus. In addition, cardiopulmonary exercise testing was also performed. These studies were obtained prior to surgical intervention, and were repeated postoperatively at 6, 12, 18, 24, and 36 months. The results obtained preoperatively were compared to those obtained throughout the postoperative monitoring period. Results: This study demonstrates that the PNT-MIT procedure results in permanent ipsilateral diaphragmatic paralysis accompanied by an approximately 8% decrease in inspiratory capacity, FVC, and total lung capacity. There was also an 11% increase in diffusing capacity noted during the period between 6 months and 3 years after PNT-MIT procedure. Despite these measurable changes in lung function, the patients reported amelioration of their dyspnea complaint within 6 months of undergoing this procedure, which was due mainly to an improvement in their cardiovascular exercise performance related to increased daily activity. Conclusions: This study demonstrates that the PNT-MIT procedure is a safe method for the restoration of drop shoulder incurred by ABPI. This surgery has an impact on measurable diaphragmatic and lung function but with minimal impact in terms of postoperative clinical symptoms and exercise performance.