Agosti, Edoardo

Abstract Introduction The endoscopic endonasal transpterygoid approach (EETPA) with or without the addition of the endoscopic-assisted sublabial anterior transmaxillary approach (ESTA) has become increasingly utilized for lesions posterior to the pterygopalatine fossa (PPF), including infratemporal fossa (ITF), lateral recess of the sphenoid sinus, Meckel's cave, petrous apex, and parapharyngeal space. The main goal of this study is to develop an educational resource to learn the steps of the EETPA for trainees. Methods EETPA and ESTA were performed in 12 specimens by neurosurgery trainees, under supervision from the senior authors. One EETPA and one ESTA were performed on each specimen on opposite sides. Dissections were supplemented with representative cases. Results After a wide unilateral sphenoidotomy, ethmoidectomy, and partial medial maxillectomy, the anteromedial bone limits of the PPF were identified and drilled out. The pterygoid progress was modularly removed. By enlarging the opening of the posterior and lateral walls of the maxillary sinus through EETPA and ESTA, respectively, the neurovascular and muscular compartments of the PPF and ITF were better identified. The EETPA opens direct corridors to the PPF, medial ITF, middle cranial fossa, cavernous sinus, Meckel's cave, petrous apex, and internal carotid artery. If a more lateral exposure of the ITF is needed, the ESTA is an appropriate addition. Conclusion Despite the steep learning curve of the EETPA, granular knowledge of its surgical anatomy and basic surgical steps are vital for those advancing their learning in complex endoscopic approaches to the ventral skull base when expanding the approach laterally in the coronal plane.

BACKGROUND: The lingual process of the sphenoid bone (LP) and the petrolingual ligament (PLL) surround laterally the internal carotid artery within the middle cranial fossa (MCF). OBJECTIVE: To study the LP and the PLL and anatomical variations considering their relationships with different structures and landmarks within the MCF, especially oriented toward the endoscopic endonasal approaches. METHODS: Seventy-two sides of dry skulls and 20 sides of embalmed specimens were studied. The measurements of the LP and the PLL were obtained, considering important landmarks in the MCF. RESULTS: The LP had a mean length and height of 5 mm and 3 mm, respectively. Its distance from the foramen lacerum was 6 mm, from the foramen ovale 10 mm, foramen rotundum 15 mm, and petrous apex 9 mm. In 44 sides (61.11%), the LP partially closed the lateral aspect of the carotid sulcus; in 17 sides (23.61%), it was found as a near-ring; and in 11 sides (15.2%), it was considered rudimentary. Considering the PLL, its length and height were, respectively, 9 mm, and 4 mm. CONCLUSION: The LP and PLL separate the carotid artery at the inferior aspect of Meckel's cave and constitute important landmarks for endoscopic endonasal approaches to Meckel's cave and MCF, and their identification and removal is essential for internal carotid artery mobilization in this area.