Surgical approach to midline skull base tumors with olfactory preservation.

Abstract

Through the frontal approach, a skull base tumor in the deep midline region is obscured by the cribriform plate. This paper demonstrates our experience of operating on seven patients with midline skull base tumors posterior to the cribriform plate using a technique of maintaining the olfactory-cribriform anatomy. Following a bifrontal craniotomy and an orbitonaso-glabellar osteotomy, a circumferential osteotomy of the cribriform plate and horizontal incision of the nasal mucosa permitted mobilization of the cribriform plate unit along with the frontal lobe, providing a wide exposure of the posterior midline area. Tumors were resected from the posterior nasopharynx, ethmoid sinus, sphenoid sinus, and upper portion of the clivus. The skull base defects were repaired with the bipedicled temporoparietal galeal flap. Two patients lost olfaction because of poor preservation of the nasal mucosa and intradural dissection of the olfactory bulb. Five patients showed complete recovery of olfaction in 8 weeks. None of the patients developed cerebrospinal fluid leakage, infection, or increased neurologic deficits. En bloc mobilization of the cribriform plate and the bipedicled temporoparietal galeal flap are very useful for the management of midline cranial base tumors posterior to the cribriform plate as long as the olfactory unit is not involved with tumors.