gms | German Medical Science

The surgical approach to the anterior skull base tumors is still under discussion either for the different microsurgical approaches, or in comparison with the possibilities offered by the endonasal endoscopic alternative. Tumors localized in the ethmoido-sphenoidal planum, with involvement of the lamina cribrosa, between the chiasm and the small sphenoid wing, are suitable for these alternatives. These lesions are traditionally treated with fronto-temporal approaches (pterional and its variants) and subfrontal (coronal and its variants). The endoscopic endonasal approach, mainly for the treatment of pituitary adenomas, may be "extended" to treat lesions of the parasellar, clinoid, clivus and the crista galli, allowing to work from the bottom without retraction of the brain and minimizing manipulation of brain structures, mainly the chiasm and the optic nerves. Although the great advantages offered for pituitary tumours, the endoscopic endonasal approach has not replaced the microsurgical technique in the anterior cranial base tumours, mainly meningiomas. The not infrequent complications, primarily csf fistula and cranial base bleeding - mainly during the learning curve course- have limited the wide diffusion of the endonasal approaches and taken the argument to a re-evaluation. Indeed the cranial approaches to the anterior skull base have advanced with less invasive surgical options, small craniotomies, using the wide CSF release – the so-called "virtual spatula" – without brain retraction under both endoscopic and high magnification microsurgery. The modern thin instrumentation and probes, like the new ultrasonic aspirators, laser technologies and 3D endoscopes, allow a new less invasive cranial surgery. The development of the craniotomies over the years has seen a progressive decrease in the extension of the bone flap, reserving the bifrontal approaches only to selected cases; also the classic pterional and fronto-orbital flaps are progressively being replaced by the unilateral sopraorbital approaches. From 2003 to 2013 at the San Camillo Neurosurgical Department 254 tumors of the anterior skull base have been operated with different surgical techniques and approaches, including the endonasal and the supraorbital. In our series we focus on the indication to the different approaches chosen based on the nature, location and extent of the lesion, with particular attention "to what is above" (enchasement rather than vascular displacement, chiasm, pituitary stalk, etc.) We discuss the surgical approaches in our series and reasons for the choices made.

The goal is to give a contribution to the present discussion on the various approaches to such lesions, to provide the best surgical solution for the best outcome.