Endonasal resection of craniopharyngiomas

Abstract

Gardner and colleagues have described their series of 16 patients who underwent an endoscopic, expanded endonasal approach (EEA) for craniopharyngioma between 1999 and 2006. The primary outcomes of their study included the following: endocrine and ophthalmological results, extent of resection, and complications. The majority of their patients underwent planned complete resection. In these patients, 73% (8 of 11) had a gross-total resection without recurrence during a mean follow-up of 34 months. No patient in the series experienced visual worsening. The postoperative rate of permanent diabetes insipidus (DI) was 8%. Cerebrospinal fluid (CSF) leaks were documented in 58% of patients. In 1 patient, a stroke occurred from a perforating vessel from a posterior cerebral artery injury. Of interest here is the classification of craniopharyngiomas into a system that is best appreciated by the endoscopic, endonasal neurosurgeon: Type I, preinfundibular; Type II, transinfundibular; and Type III, retroinfundibular. In theory, this is an attractive classification system. In practice, however, there will be instances in which the craniopharyngiomas are either too large and the stalk obscured, or the MR images will be inadequate to fully ascertain the location of the tumor with respect to the infundibulum. I would like to commend the authors on their willingness to tackle some of the more difficult types of craniopharyngiomas (for example, the Type IIIa and IIIb lesions) through an EEA. Years ago, I would have thought such an approach to the “retrochiasmatic” craniopharyngioma would have been impossible. Now, with the advent of the techniques that have been uniquely shared by the minimally invasive neurosurgeon and otolaryngologist and which are expounded on in this study, craniopharyngiomas of all types can be the target of EEA. As with all new techniques that come forward for analysis when compared with established, conventional ones, a critical review of the complications must be undertaken. Here, it is clear that EEA for craniopharyngioma is well tolerated, and the vast majority of patients do well after tumor resection. Endocrine and ophthalmological functions were reasonably well preserved and/or maintained. The one area, of course, where greater strides will need to be taken and where improvements in technique will be mandatory is with the rate of CSF leakage. However, it sounds as though the authors are well on their way to improving their outcomes with CSF leaks by using vascularized mucosal flaps together with local reinforcement of the sellar floor. This report by Gardner and associates is more than a technical note, but is not yet quite at the level of the larger published series on craniopharyngioma1–4 in which more patients with craniopharyngioma have been studied and followed, in some instances, for longer periods of time. In all series, however, including the present one, recurrences of craniopharyngioma are a fact of life. The rate of recurrence may be as high as 40% in some series. The treatment of the recurrent craniopharyngioma is a vexing problem, and one wonders whether patients who were first treated using the EEA would again be candidates for a repeated procedure using this approach. The EEA described here was performed in adults. As craniopharyngiomas commonly occur in children, it would be interesting to use this approach in the child with a craniopharyngioma. In this regard, the limitations would likely be similar to those observed with the transsphenoidal approach in this age group: small nares, nonpneumatized sella, and smaller midline corridor between the carotid arteries. Finally, as the authors expand their series and gather more patients for analysis, I exhort them to analyze the effects of EEA on the neuropsychology of their patients. It is here that I suspect that EEA may be a beneficial approach over craniotomy and subfrontal or pterional approaches to craniopharyngioma.