[Preservation of olfaction in frontal transbasal approach]

Lesions in the frontal base and clival area have conventionally been approached using the transbasal approach described by Derome and Guiot. However, this approach necessitates removal of the crista galli and sectioning of the olfactory rootlets with the associated risk of anosmia and cerebrospinal fluid leak and, in addition, complex reconstruction of the frontal base is required. We describe a new approach to deeply situated tumors in the frontal base, parasellar and clival area which is a modification of Spetzler's craniofacial approach with preservation of olfaction. In this approach, circumferential osteotomy cuts are made around the cribriform plate to permit en block removal with its attachment to both the dura and underlying mucosa. Opening of the dura is avoided and the cribriform bone is used to reconstruct the frontal base. Three patients underwent surgery using this approach for treatment of recurrent pituitary adenoma in two cases and for clivus chordoma in one. In one patient, olfactory function was not preserved because resection of nasal mucosa was small. In the other two patients, however, olfaction was preserved by creating a cribriform plate complex with a sufficient area of resection of nasal mucosa and tumors were completely removed. Olfaction can be preserved, CSF leakage can be prevented, and facial skin incision and complex frontal base reconstruction can be avoided when this technique for maintaining normal olfactory-cribriform anatomy is used in frontal transbasal approaches.