Axillary Nerve Transection After Removal of An Axillary Merkel Cell Carcinoma
Matthew Peter Fahrenkopf, MD1, John P Kelpin, MD1, Joshua P Kelley, MD1, Paul G Wright, MD2 and Johanna R Krebiehl, MD2,3, (1)Spectrum Health/Michigan State University, Grand Rapids, MI, (2)Spectrum Health, Grand Rapids, MI, (3)Plastic Surgery Associates, Grand Rapids, MI
Introduction: Oncologic resection of malignant masses involves inclusion of surrounding healthy tissue. Often, the clinical distinction between normal and neoplastic tissue is difficult to discern. Extrinsic factors such as chemotherapy, radiation, prior resection can all contribute to distortion of the surgical field. This makes it challenging to preserve vital structures while obtaining pathologic clear margins. Tumors of the axilla pose additional challenges, given their proximity to the brachial plexus, subclavian and brachial vasculature, and the lungs. Peripheral nerve injuries are therefore not uncommon in upper extremity oncologic surgery and early recognition is imperative to preserve patient function and reduce morbidity.
Materials & Methods: A 40 year old woman underwent neoadjuvant chemoradiation therapy for a Merkel cell carcinoma of the left axilla. Post treatment scans demonstrated a substantial reduction in tumor bulk, but residual disease around the axillary neurovascular structures. Consequently, she underwent resection and lymphadenectomy by the surgical oncology team. Postoperative day one, the patient had an inability to externally rotate the shoulder, flex at the shoulder, or extent at the elbow or wrist. The patient was urgently taken back to the operating room for exploration and identification of a potential brachial plexus injury.
Results: Surgical exploration demonstrated complete transection of the axillary nerve just distal to the bifurcation from the radial nerve. Proximal and distal stumps were identified with the aid of an intraoperative nerve stimulator and then preliminarily suture tagged. The nerve gap was measured and found to be 6 centimeters. Autologous cable nerve grafting from the patient's right sural nerve was performed to span the gap between axillary nerve ends. Repair was completed with epineural sutures and fibrin glue. The radial nerve was also assessed with an intraoperative nerve stimulator and found to be in continuity. The patient continues to be monitored for ongoing clinical improvement and return of muscular function.
Conclusions: Peripheral nerve injuries are not uncommon in upper extremity oncologic resections. Normal anatomic boundaries and structures can become blurred by neoplastic invasion and presurgical treatments. All patient's undergoing resection should be examined postoperatively for nerve deficits. Physicians should have a low threshold for returning to the operating room should a brachial plexus or peripheral nerve be suspected. Time is function, and delays in diagnosis and treatment can drastically affect patient morbidity. Autologous nerve grafting still remains the gold standard for repair.
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