Endonasal versus transcranial resection.

Anterior skull base meningiomas are among the easiest to remove completely with a very low morbidity rate and excellent long-term outcome.11 This goal can be reached in nearly all frontobasal midline meningiomas by using a small minimally invasive frontolateral craniotomy. The approach allows one to achieve optimal functional results (both ophthalmological and endocrinological) and to avoid new deficits and complications in general, which is the second goal of their treatment. From a historical point of view larger craniotomies have been favored because they offer a better overview of the whole tumor and of the surrounding structures, as well as more space for manipulations, giving a feeling of safety to the surgeon. The anatomical location and relations of some meningiomas to the surrounding vital structures restrict the operative radicality, whatever approach is used. Examples of such tumors are the cavernous sinus and the petroclival meningiomas. The introduction of the surgical microscope improved intraoperative illumination and visualization. Tumor removal became feasible through smaller craniotomies. However, the use of the microscope did not necessarily mean that a less invasive technique was applied. Such lessinvasive miscrosurgical techniques were developed later by neurosurgical masters, such as Yaşargil and Samii. The keyhole concept, which benefits from the application of both microscope and endoscope, was elaborated by Perneczky. In the case of frontobasal meningiomas, the gentle dissection of the tumor capsule from the optic nerve/tract and from the hypothalamopituitary system with their sophisticated vascular supply became possible. Samii described recently his interindividual improvement in terms of achieving more radical resection and better functional results. In a series of 72 cases with tuberculum sellae meningiomas, in which the bifrontal, then the pterional and then—the frontolateral approach were used, total resection was achieved in 92%. 10 Notably, the rate of visual improvement increased from 46% to 64%, and then to 78% with each of the approaches. Fahlbusch published a series of 47 patients operated on in the period 1982–2002: 46 of 47 of the meningiomas were removed totally and the rate of visual improvement was 80%. 6 Until 2006, additional 22 cases were operated and further improvement of the results was possible: all tumors were resected completely and the visual improvement rate was 85%. Mathiesen,9 who favors the routine opening of both optic foramina, achieved even better rate of visual improvement—90%. Currently at the International Neuroscience Institute, we approach all frontobasal midline, including the large and giant olfactory meningiomas, via the minimally invasive frontolateral craniotomy.5 We cannot avoid the impression that some neurosurgeons—those that are not satisfied with their own surgical results, those who have never had the chance to be trained in microsurgery by experts, and those who started their neurosurgical training with endoscopy and want to expand its indications—are inclined to favor the endonasal transsphenoidal, respectively transethmoidal approach to the anterior skull base. Harvey Cushing himself, who had pioneered the transsphenoidal approach for pituitary adenomas, changed from the transsphenoidal to the transcranial technique, which offered better visualisation and allowed more radical tumor resection. The first renaissance of transsphenoidal surgery occurred with the introduction of operating microscope; the second one, with the introduction of the endoscope. The latter technique, pioneered first by Jho, and then by Diviitis and Cappabianca, allows for even better illumination and visualisation of all structures, a panoramic overview of the operative field, and a possibility to “look around the corner. ” The excellent operative results of microsurgery for pituitary adenomas in experienced hands are meanwhile going to be achieved also with the pure endoscopic technique. Adequate publications on the outcome of endoscopic surgery should be expected. The extended transsphenoidal approach to suprasellar lesions via the tuberculum sellae is best suited for surgery of small lesions.2 Larger tumors, such as craniopharyngiomas extending to the foramen of Monro or tumors with lateral parasellar extension, are less suitable. For us, the main domain of the extended endonasal transsphenoidal approach is not the anterior but the posterior parasellar and clival area, for example, in cases of chordomas. In this article, the authors from Rochester and Bologna present a series of 13 patients with frontobasal meningiomas, surgically treated by Frank and Pasquini in Bologna.12 Meta-analysis of the literature is also perEditorial See the corresponding article in this issue (E15).