Combined Endoscopic and Open Cranial Approach for Treatment of Skull Base Lesions: A Case Series and Lessons Learned.

Introduction: Surgical treatment of skull base pathologies is frequently discussed in the context of endoscopic endonasal or transcranial approaches. Combined endoscopic and open approaches have been utilized in a staged or sequential fashion, with the goal of reducing the risk of postoperative cerebrospinal fluid leak, morbidity, wound infection/complication, and failure to achieve adequate reconstruction. However, few studies have described the concurrent use of endoscopic endonasal and transcranial approaches to safely address complex skull base pathologies. Methods: We treated 13 patients with primary skull base tumors (sinonasal undifferentiated carcinoma/esthesioneuroblastoma), recurrent tumors, infection, and skull base defect/encephalocele. Out of the thirteen patients, eight had undergone prior endoscopic and/or open transcranial approaches for resection of their pathologies. Additionally, 3/13 patients underwent radiation or chemotherapy radiation prior to the combined approach. Results: The desired clinical outcome (i.e., gross total tumor resection, resolution of infection, and skull base resection/repair) was achieved in 12/13 cases. One case had subtotal resection (Simpson grade III) of an olfactory groove meningioma. Postoperatively, there was one 30-day mortality due to pulmonary infarction, one case with hydrocephalus requiring ventriculoperitoneal shunt placement, and one flap infection due to postoperative cocaine use resulting in revisions and hospice. Importantly, no patients experienced postoperative CSF leaks, including those who underwent postoperative chemotherapy/radiation. Conclusion: This case series suggests that a concurrent combined endoscopic transcranial approach, in carefully selected patients, can treat a wide range of complex and recurrent skull base pathologies resistant to previous treatment, with a reasonable rate of postoperative wound/leak complications.