VATS phrenic nerve harvesting for brachial plexus neurotization: literature review and our experience

Introduction: Brachial plexus traumatic lesions often lead to severe upper extremity deficits that dramatically compromise quality of life of mostly young patients. Optimal treatment aims to restore elbow flexion transferring various donor nerves. Phrenic nerve (PN) is a powerful source of transferable axons and, despite supraclavicular sectioning being the most used technique, it can be harvested through video-assisted thoracoscopic surgery (VATS). Evidence acquisition: About PN harvesting, less than 20 articles were found in Literature. Most of them are clinical case-reports or case-series or expert opinions. Most of these studies are from China and East Asia and very rarely from Europe; none from Italy. Therefore, we present our experience in PN VATS harvesting in two patients, first cases reported in Italy. Evidence synthesis: Few papers explore risks and benefits of PN as a donor site for brachial plexus reconstruction. There is no clear consensus in the literature whether a traditional approach or minimally invasive surgery is advisable to harvest PN for neurotization. Currently there's no clear indication nor a definitive contraindication about routine use of PN for surgical treatment of BPTLs, it's mostly a matter of choosing the best donor nerve for every single patient. This choice depends on the patient's characteristics, type of traumatic lesion, time from the traumatic event and on the center's experience. The only real concern about using PN as a donor is the potential loss of pulmonary function. In our center two patients with complete brachial plexus avulsion underwent PN transfer via VATS in 2021. Usually, recovery of muscle function depends on time between injury and surgical repair. A commonly accepted recommendation is to perform surgery within six months from the traumatic lesion12. In our experience, the time between trauma and surgery was five months for patient A and six months for patient B. Even if some authors13 consider previous thoracic trauma with rib fractures a major contraindication for homolateral PN harvesting, we believe that the presence of pleural adhesions should not exclude a patient from surgery. No intra or postoperative complications were observed. Both patients were discharged on IV postoperative day. An intense rehabilitation program within three months after surgery is mandatory and regular follow-up is needed to monitor any improvement. No respiratory symptoms or discomfort is recorded up to now. Conclusions: Nerve transfer is a safe and reliable surgical reconstructive procedure and phrenic nerve, due to its pure motor nature, is a very good donor for brachial plexus injuries14. VATS is a valid procedure to guarantee a much longer nerve, avoiding any graft use, and doesn't seem to determine significant pulmonary function loss. Previous thoracic trauma, rib fractures and pneumothorax are commonly considered contraindications for VATS harvesting. However, a major trauma leading to BPTL often implies homolateral thoracic trauma with or without rib fracture or pneumothorax. This could be a reasonable justification to reconsider those contraindications and extend the potential cohort of patients that could benefit from this technique.