Endoscopic reconstruction of posterior cranial fossa defects

Posterior skull base reconstruction via an endoscopic endonasal approach is challenging not only for the size of the defects but mainly because of high-flow cerebrospinal fluid (CSF) leak, the effect of gravity, and the lack of supporting structures with critical neurovascular structures around the defect such as the internal carotid artery and cranial nerves. For these reasons, posterior skull base approaches are traditionally considered high-risk surgical procedures associated with non-negligible rates of postoperative complications, including leaks recurrence, meningitis, encephalitis, and pneumocephalus. Recent experiences on posterior skull base reconstruction, however, are encouraging, with improved outcomes compared with the past. This might be related to refinements of the free grafting techniques, such as multilayer repair and gasket-seal technique, which reduced the CSF leak rate even in this critical area. Moreover, many pedicled vascularized flaps have been introduced, including the Hadad-Bassagasteguy flap, the middle turbinate flap, and the U-shaped nasopharyngeal flap, with a global decrease in CSF leak incidence. In selected cases, regional vascularized flap such as the temporoparietal fascial flap and microvascular free flaps have been proposed to manage complex cases. This chapter illustrates current trends in posterior skull base reconstruction, analyzing surgical options available and the most appropriate recommendations for postoperative management. Recent pertinent literature has been also reviewed to offer a comprehensive overview of up-to-date clinical recommendations.