Free Flap Reconstruction of Skull Base Defects: A Retrospective Review

Due to the anatomic challenges of surgery of the anterior and lateral skull base, defects in these regions pose complex reconstructive challenges, given the need to anatomically isolate the intracranial cavity to prevent CSF leak and infection. While microvascular free tissue transfer is an increasingly used reconstructive technique for large or complex skull base defects following oncologic ablative surgery, the risk of perioperative morbidity is not well described. A retrospective chart review was conducted in an effort to better understand the risk factors, complications, and outcomes of free tissue transfer for skull base reconstruction. 28 patients were identified with tumors requiring anterior and/or lateral skull base resection and reconstruction using microvascular free flaps at a tertiary care hospital from 2009 to 2015. Of these patients, 22 were male and 6 were female. The most common initial diagnosis was squamous cell carcinoma (60.71%). The majority of tumors invading the skull base had a sinonasal origin (71.43%). Of the 19 skull base tumors that had staging data available, 7 were classified as stage 4a, 5 as stage 3, 4 as stage 4b, and 2 as stage 2. The most common flaps used were anterolateral thigh free flaps (57.14%), followed by scapular (14.28%), and rectus abdominis (10.71%) flaps. There were 8 relevant complications, which included a CSF leak, airway edema after neck dissection, a serious incident of postoperative bleeding from a donor site that required an emergent surgical evacuation of a hematoma, and acute blood loss anemia requiring multiple blood transfusions. There were a total of three free-flap–specific complications. The first complication was flap ischemia caused by an arterial thrombus in a known smoker that required debridement, removal, and replacement of the flap. The second complication involved pneumocephalus and removal of the free flap secondary to swelling and compression of the brain at the surgical site. The third complication involved venous congestion that required revision surgery. In this preliminary study, we found that in this high-risk patient population, skull base defects can be repaired utilizing free flap reconstruction with a similar morbidity profile to other head and neck subsites. By adding to the fund of knowledge for free tissue transfer for skull base reconstruction, we hope to decrease complication rates and improve surgical outcomes while reducing hospital length of stay and costs.