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Objectives/Hypothesis This cadaveric study analyzes the endoscopic endonasal anatomy of the ophthalmic division of the trigeminal nerve (V1), from the middle fossa to its orbital entry via the superior orbital fissure. Anatomical relationships with the surrounding cranial nerves and blood vessels are described, with emphasis on their clinical correlation during surgery in this region. Our objective was to describe the anatomical relationships of the ophthalmic division of the trigeminal nerve. Study Design Cadaveric study. Methods Thirty middle cranial fossae, in adult human cadaveric specimens, were dissected endonasally under direct endoscopic visualization. During the dissection, we noted the relationships of the V1 nerve with the other trigeminal branches, as well as with the oculomotor and trochlear nerves, the paraclival and cavernous portions of the internal carotid artery, and the superior orbital fissure (SOF). Results The V1 nerve is the most superior trigeminal branch and runs upward and obliquely, along the middle portion of the lateral wall of the cavernous sinus. The V1 nerve joins the oculomotor and trochlear nerves to exit the cavernous sinus and enter the orbit through the SOF. Ten percent of the specimens displayed the trochlear nerve running along as a mate of the V1 nerve. The V1 nerve borders two key triangles in the lateral wall of the cavernous sinus, and the Parkinson's and anteromedial triangles. Conclusions In this study, the V1 nerve was a constant and reliable landmark, thus allowing the identification of the anteromedial triangle. This potential space can serve as an adequate window to access the temporal lobe. Knowledge of this anatomy is essential when planning and executing endonasal surgery in this region. Level of Evidence NA Laryngoscope, 125:1284-1290, 2015 [ABSTRACT FROM AUTHOR]

Background: The origin of the ophthalmic artery is within the surgical field of endoscopic endonasal approaches (EEAs) to the suprasellar and parasellar regions. However, its anatomy from the endoscopic point-of-view has not been adequately elucidated., Objective: To highlight the anatomy of the ophthalmic artery origin from an endoscopic endonasal perspective., Methods: The origin of the ophthalmic artery was studied bilaterally under endoscopic visualization, after performing transplanum/transtubercular EEAs in 17 cadaveric specimens (34 arteries). Anatomic relationships relevant to surgery were evaluated. To complement the cadaveric findings, the ophthalmic artery origin was reviewed in 200 "normal" angiographic studies., Results: On the right side, 70.6% of ophthalmic arteries emerged from the superior aspect, while 17.6% and 11.8% emerged from the superomedial and superolateral aspects of the intradural internal carotid artery, respectively. On the left, 76.5%, 17.6%, and 5.9% of ophthalmic arteries emerged from the superior, superomedial, and superolateral aspects of the internal carotid, respectively. Similar findings were observed on angiography. All ophthalmic arteries emerged at the level of the medial opticocarotid recess. Overall, 47%, 26.5%, and 26.5% of ophthalmic arteries (right and left) were inferolateral, inferior, and inferomedial to the intracranial optic nerve segment, respectively. On both sides, the intracranial length of the ophthalmic artery ranged from 1.5 to 4.5 mm (mean: 2.90 ± standard deviation of 0.74 mm)., Conclusion: Awareness of the endoscopic nuances of the ophthalmic artery origin is paramount to minimize the risk of sight-threatening neurovascular injury during EEAs to the suprasellar and parasellar regions., (Copyright © 2018 by the Congress of Neurological Surgeons.)

Object: Skull base chondrosarcomas are slow-growing, locally invasive tumors that arise from the petroclival synchondrosis. These characteristics allow them to erode the clivus and petrous bone and slowly compress the contents of the posterior fossa progressively until the patient becomes symptomatic, typically from cranial neuropathies. Given the site of their genesis, surrounded by the petrous apex and the clival recess, these tumors can project to the middle fossa, cervical area, and posteriorly, toward the cerebellopontine angle (CPA). Expanded endoscopic endonasal approaches are versatile techniques that grant access to the petroclival synchondrosis, the core of these lesions. The ability to access multiple compartments, remove infiltrated bone, and achieve tumor resection without the need for neural retraction makes these techniques particularly appealing in the management of these complex lesions., Methods: Analysis of the authors' database yielded 19 cases of skull base chondrosarcomas; among these were 5 cases with predominant CPA involvement. The electronic medical records of the 5 patients were retrospectively reviewed for age, sex, presentation, pre- and postoperative imaging, surgical technique, pathology, and follow-up. These cases were used to illustrate the surgical nuances involved in the endonasal resection of CPA chondrosarcomas., Results: The male/female ratio was 1:4, and the patients' mean age was 55.2 ±11.2 years. All cases involved petrous bone and apex, with variable extensions to the posterior fossa and parapharyngeal space. The main clinical scenario was cranial nerve (CN) palsy, evidenced by diplopia (20%), ptosis (20%), CN VI palsy (20%), dysphagia (40%), impaired phonation (40%), hearing loss (20%), tinnitus (20%), and vertigo/dizziness (40%). Gross-total resection of the CPA component of the tumor was achieved in 4 cases (80%); near-total resection of the CPA component was performed in 1 case (20%). Two patients (40%) harbored high-grade chondrosarcomas. No patient experienced worsening neurological symptoms postoperatively. In 2 cases (40%), the symptoms were completely normalized after surgery., Conclusions: Expanded endoscopic endonasal approaches appear to be safe and effective in the resection of select skull base chondrosarcomas; those with predominant CPA involvement seem particularly amenable to resection through this technique. Further studies with larger cohorts are necessary to test these preliminary impressions and to compare their effectiveness with the results obtained with open approaches.