Diaphragmatic Paralysis Following Thoracic Outlet Decompression: An Evaluation of Secondary Phrenic Nerve Reconstruction for Salvage

BACKGROUND: Thoracic outlet syndrome (TOS) involves the compression of neurovascular structures within the thoracic outlet, defined as a space at the base of the neck, superior to the first rib and posterior to the clavicle. Surgical management most commonly requires a supraclavicular approach to allow for anterior and middle scalene muscle resection, cervical and first rib resection, and brachial plexus decompression. Pectoralis minor tenotomy and vascular decompression may also be indicated. While these interventions may successfully relieve compression within the thoracic outlet, they carry a risk of iatrogenic phrenic nerve injury (PNI). PNI-induced diaphragm paralysis often results in symptomatic pulmonary dysfunction. Phrenic nerve reconstruction may offer an effective treatment for functional diaphragm salvage after PNI following TOS surgery. METHODS: We performed a retrospective review of seventeen patients with PNI following TOS surgery referred for management at a tertiary referral center who underwent phrenic nerve reconstruction to restore functional diaphragm activity. RESULTS: There were seventeen patients (10 females and 7 males with a mean age of 47) who were treated for chronic, symptomatic PNI following TOS surgery. Two patients were lost to follow-up. The mean interval from PNI to secondary phrenic nerve reconstruction was 19 months. Following phrenic nerve intervention, twelve of fifteen patients (80%) reported improvement, ten of whom demonstrated partial or complete functional diaphragm recovery on objective analyses. CONCLUSIONS: Surgical treatment for TOS has demonstrable therapeutic benefits to patients suffering from this disease. However, PNI is a potential complication associated with TOS surgery. Secondary phrenic nerve reconstruction to achieve salvage of diaphragm function can successfully address this risk and reduce or eliminate the morbidity associated with TOS-related PNI.