Suprasellar Meningiomas

Abstract

To the Editor: We read with interest the recent article by Drs. Ciric and Rosenblatt (3) concerning the operative technique used in the surgical excision of suprasellar meningiomas. In our opinion, these authors wrote a clear, step-by-step description of the surgical strategy. Nevertheless, herein we add some observations and ask the authors some questions: The authors presented a series of 24 patients who had undergone surgery between 1971 and 2001. Among these patients, three had meningiomas arising at the level of the anterior clinoid that “also involved the dura of the tuberculum sellae, the diaphragma sellae, or both” (3, p 1372). Why did the authors include these cases in their surgical series? The general consensus is that meningiomas of the clinoid must be distinguished from suprasellar meningiomas because of differences in operative strategy, difficulties encountered, and overall morbidity and mortality (1, 4). Meningiomas of the suprasellar area can be handled safely with the use of a pterional approach. The removal of the orbital rim does not improve a craniotomy cut flush with the roof of the orbit if an adequate extradural resection of the greater and lesser wings of the sphenoid and the opening of the superior orbital fissure have been performed already. We add the extradural removal of the anterior clinoid process if the tumor presents as an extension of the floor of the sella and/or the optic canal, information that is obtained from the MRI scan. In our experience the wide opening of the sylvian fissure with release of cerebrospinal fluid allows to minimize the necessity of brain retraction by means of spatulas, as it appear in the pictures presented through the whole article. We think that the sucker itself can be often used as the only instrument to perform a minimal brain retraction. In the Results, the authors report 7 of 24 patients in whom a subtotal resection of the tumor was achieved and 1 patient in whom partial resection was performed. In such cases, the tumor “straddled (rather than displaced), and in some cases engulfed, the pituitary stalk” (3, p 1377). In our experience, we have found that the main hindrance in performing a radical excision of the tumor is the engulfment of some perforating branches of the anterior communicating artery. The pituitary stalk usually presents its own arachnoidal sheath, which permits a relatively safe microsurgical dissection. Concerning the patient with a “tuberculum clinoid” meningioma infiltrating the optic nerve sheath (3, p 1377), the subtotal resection of the tumor did not result in the regression of a preoperative visual deficit. The same patient showed a “near-complete recovery of vision” (3, p 1377) after radiotherapy focused on the tumor residual. This statement is hard to accept. Radiotherapy in the area of the optic nerve is always a high-risk procedure. Last, we emphasize that the preoperative differential diagnosis between diaphragma sellae meningiomas and nonsecreting pituitary macroadenomas with suprasellar extension may be difficult. This is particularly true in cases of subdiaphragmatic meningiomas—so-called type C meningiomas—according to Kinjo et al. (4). We have collected 42 cases of suprasellar meningiomas from our own surgical series. Among these cases, five patients underwent transsphenoidal surgical exploration because of preoperative misdiagnosis (2). Enrico de Divitiis Giuseppe Mariniello Paolo Cappabianca