Roadmap to Ventral Craniocervical Junction Through the Endonasal Corridor: Anatomic Evaluation of Inverted U-Shaped Nasopharyngeal Flap Exposure in a Cadaveric Study.

BACKGROUND: There is a paucity of data in the literature describing quantitative exposure of the ventral craniocervical junction through the endonasal corridor in a safe manner mindful of locoregional anatomy. OBJECTIVE: To quantify ventromedial exposure of O-C1 and C1-2 articular structures after turning an inverted U-shaped nasopharyngeal flap (IUNF) and to obtain measurements assessing the distance of flap margins to adjacent neurovascular structures. METHODS: In 8 cadaveric specimens, an IUNF was fashioned using a superior incision below the level of the pharyngeal tubercule of the clivus and lateral incisions in the approximate region of Rosenmuller fossae bilaterally. Measurements with calipers and/or neuronavigation software included flap dimensions, exposure of O-C1 and C1-2 articular structures, inferior reach of IUNF, and proximity of the internal carotid artery (ICA) and hypoglossal nerve to IUNF margins. RESULTS: The IUNF facilitated exposure of an average of 9 mm of the medial surfaces of the right/left O-C1 joints without transgression of the carotid arteries or hypoglossal nerves. The C1-2 articulation could not be routinely accessed. The margins of the IUNF were not in close (<5 mm) proximity to the ICA in any of the 8 specimens. In 6 of 8 specimens, the dimensions of the IUNF were in close (<5 mm) horizontal or vertical proximity to the hypoglossal foramina. CONCLUSION: The IUNF provided safe and reliable access to the medial O-C1 articulation. Given the close proximity of the exocranial hypoglossal foramen, neuronavigation assistance and neuromonitoring with attention to the superolateral IUNF margin are recommended.

Management of a complex glomus jugulare tumor with severe brainstem compression.

Surgery of glomus jugulare tumors is complex, but when these tumors have a large intradural component and cause brainstem compression they became a challenge to the surgeon. It is crucial to preoperatively understand the anatomy of the tumor and analyze its relationship with the temporal bone, facial nerve, and foramen jugular neurovascular structures. We present a case of a male patient with a complex glomus jugulare tumor causing severe brainstem compression. Nuances of technique and surgical pearls related to the management of complex jugulare tumors are discussed and illustrated in this operative video. The video can be found here: https://youtu.be/oCjzp0kFRGc.

Subtemporal approach for the resection of a midbrain cavernous malformation: evaluation of safe surgical corridors.

Brainstem cavernous malformation management is complex due to its critical location and deleterious effect when bleeding. Therefore, every case should be thoroughly analyzed preoperatively. We present the case of a female patient with a midbrain cavernous malformation. A comprehensive anatomical and clinical analysis of the surgical corridors is done to decide the safest route. A subtemporal approach was done and the lateral mesencephalic sulcus and vein were important anatomical landmarks to guide the safe entry zone. Nuances of technique and surgical pearls related to the safe entry zones of the midbrain are discussed and illustrated in this operative video. The video can be found here: https://youtu.be/vYA-IgiT2lU.