Endoscopic anterior transmaxillary "transalisphenoid" approach to Meckel's cave and the middle cranial fossa: an anatomical study and clinical application.

OBJECTIVE Multiple approaches have been designed to reach the medial middle fossa (for lesions in Meckel's cave, in particular), but an anterior approach through the greater wing of the sphenoid (transalisphenoid) has not been explored. In this study, the authors sought to assess the feasibility of and define the anatomical landmarks for an endoscopic anterior transmaxillary transalisphenoid (EATT) approach to Meckel's cave and the middle cranial fossa. METHODS Endoscopic dissection was performed on 5 cadaver heads injected intravascularly with colored silicone bilaterally to develop the approach and define surgical landmarks. The authors then used this approach in 2 patients with tumors that involved Meckel's cave and provide their illustrative clinical case reports. RESULTS The EATT approach is divided into the following 4 stages: 1) entry into the maxillary sinus, 2) exposure of the greater wing of the sphenoid, 3) exposure of the medial middle fossa, and 4) exposure of Meckel's cave and lateral wall of the cavernous sinus. The approach provided excellent surgical access to the anterior and lateral portions of Meckel's cave and offered the possibility of expanding into the infratemporal fossa and lateral middle fossa and, in combination with an endonasal transpterygoid approach, accessing the anteromedial aspect of Meckel's cave. CONCLUSIONS The EATT approach to Meckel's cave and the middle cranial fossa is technically feasible and confers certain advantages in specific clinical situations. The approach might complement current surgical approaches for lesions of Meckel's cave and could be ideal for lesions that are lateral to the trigeminal ganglion in Meckel's cave or extend from the maxillary sinus, infratemporal fossa, or pterygopalatine fossa into the middle cranial fossa, Meckel's cave, and cavernous sinus, such as schwannomas, meningiomas, and sinonasal tumors and perineural spread of cutaneous malignancy.