[Enlarged transbasal approach by mobilization of the medial fronto-orbital ridge].

Tumors involving the base of the skull are best approached by the transbasal route as described by Derome. However this approach can be improved by mobilization of the medial part of the supra-orbital ridge according to the technical principles used in treatment of craniosynostosis. This allows a wide exposure of the ethmoido-sphenoidal area with minimal retraction of the frontal lobes. The axis of working becomes parallel and even inferior to the plane of the cribriform plate and gives a better access to the upper part of the clivus. Rhinologic complementary approach (rhinoseptal or transfacial) can be associated with this technique. However a more anterior part of the nasal mucosae is exposed by this procedure: one can control the mucosae in front of the tumor and avoid a complementary rhinoseptal route. This simple technical trick has been used in seven cases with satisfactory results.