Search

Objective To describe an endoscopic anterolateral surgical route to the lateral portion of Meckel's cave. Methods A sublabial transmaxillary transpterygoid approach was performed in 6 cadaveric heads (12 sides). A craniectomy was drilled between the foramen rotundum (FR) and foramen ovale (FO) with defined borders. Extradural dissection was performed up to the V2–V3 junction of the trigeminal ganglion. The working space was analyzed using anatomic measurements. Results The approach allowed for extradural dissection to the lateral aspect of Meckel's cave and provided excellent exposure of V2, V3, and the V2–V3 junction at the gasserian ganglion. The mean distance between the FR and FO along the pterygoid process of the sphenoid bone was 21.3 ± 2.8 mm (range, 18–24.4 mm). The mean distance of V2 and V3 segments from their foramina to the gasserian ganglion junction was 12.0 ± 2.3 mm (range, 9.2–14.6 mm) and 15.2 ± 2.7 mm (range, 12.3–18.5 mm), respectively (6 sides). A potential working area (mean area, 89 mm 2 ) is described. Its superior edge is from the FR to the V2–V3 junction at the gasserian ganglion, its inferior edge is from the FO to the V2–V3 junction at the gasserian ganglion, and its base is from the FO to the FR. The surgical anatomy of the infratemporal fossa, pterygopalatine fossa, and lateral Meckel's cave is highlighted. Conclusions An endoscopic anterolateral sublabial transmaxillary transpterygoid approach between the FR and FO avoids crossing critical neurovascular structures within the cavernous sinus and pterygopalatine fossa and can provide a safe surgical corridor for laterally based lesions in Meckel's cave. [ABSTRACT FROM AUTHOR]

Objective Surgical freedom and the angle of attack influence approach selection for open cranial base approaches, but these concepts have not been well studied in minimal-access endoscopic approaches. We therefore developed a methodology to study surgical freedom and angle of attack in two endoscopic transmaxillary transpterygoid approaches, the endonasal ipsilateral uninostril medial maxillotomy and the sublabial Caldwell-Luc anterior maxillotomy. Methods Dissections were performed bilaterally in three formalin-fixed cadaver heads (six sides). For each approach, three progressively lateral and posterior anatomic targets were identified. Utilizing frameless stereotaxy, surgical freedom using the vector cross-product method was calculated for both approaches for each target. The mean and maximum possible angles of attack were calculated in the axial and sagittal planes. Results Compared to the endoscopic endonasal-transmaxillary approach, the endoscopic Caldwell-Luc approach offered significantly greater surgical freedom to the genu of the internal carotid artery ( P = 0.02), foramen rotundum ( P = 0.03), and foramen ovale ( P = 0.03). Mean and maximum possible angles of attack were also significantly different between the two approaches for each target. The Caldwell-Luc approach offered a more bottom-up approach in the sagittal plane and a more head-on approach in the axial plane to each target ( P < 0.05). Conclusions We have successfully developed a model for comparing endoscopic skull base approaches. Both the endonasal medial maxillotomy approach and Caldwell-Luc approach provided endoscopic access to each target. However, the sublabial Caldwell-Luc approach offered greater surgical freedom and a more head-on approach than the endonasal medial maxillotomy. These differences in surgical freedom and angles of attack may be useful to consider when planning minimal-access approaches. [ABSTRACT FROM AUTHOR]