The Quadrangular Space, Endonasal Access to the Meckel Cave: Technical Considerations and Clinical Series.

OBJECTIVE: An anteromedial corridor via an expanded endoscopic endonasal approach to the Meckel cave (MC) was described more than a decade ago. However, few clinical series or endoscopic endonasal technical contributions exist concerning this type of approach to this complex region. METHODS: We present a detailed description of the surgical technique for this approach reviewing the original technique and adding clarifying conceptual notions. We conducted a multicenter retrospective study selecting patients who underwent endonasal endoscopic surgery for lesions exclusively limited to the MC in the past 6 years. Intraoperative and postoperative complications were analyzed. The study of 10 cadaveric specimens provides additional information. RESULTS: We performed a fully endoscopic anteromedial corridor to the MC in 18 patients. The most prevalent pathologic finding was schwannoma of the V nerve in 4 patients. Sixth cranial nerve palsy (13 patients) and trigeminal dysfunction (10 patients) were the predominant preoperative clinical signs. There were no remarkable intraoperative complications. Corneal keratopathy caused by dry eye syndrome affected 3 patients and V2 residual neuralgia appeared postoperatively in 2 patients. Six patients recovered from sixth cranial nerve palsy, and 2 showed improvement in preoperatively referred facial pain. CONCLUSIONS: The front door to the MC via the endonasal anteromedial corridor could be a good option. Understanding of the anatomy and the concept of the quadrangular space is crucial to performing this technique safely, which has few complications in experienced hands. Recovery from sixth nerve palsy is possible with this approach. Corneal keratopathy in these patients is a potential complication.

How I do it: endoscopic endonasal approach to the inferior third of the clivus.

BACKGROUND: Nowadays, endoscopic endonasal expanded approach targeting for the clival lower third is well described in literature. Nonetheless, great variations can be found among surgical groups, specially during the earlier stages of this procedure. METHOD: We present a step by step description of the clival lower third approach until entering the dural space, setting its bony limits. We describe the basipharyngeal flap tailoring as a helpful option for latter reconstruction. The study of cadaveric specimens adds clarifying dissections. CONCLUSIONS: The expansion in the coronal plane is providential in most of the intradural lesions of the inferior clivus. Basipharyngeal flap may help seal the surgical defects in this area.

Endoscopic radical hypophysectomy: how I do it.

BACKGROUND: Total hypophysectomy it is a classical procedure that currently has many indications especially in patients with Cushing syndrome without good endocrine control. Expanded endonasal endoscopic techniques grant us an alternative standpoint to the classic trans-sphenoidal microscopic approach and a comprehensive assessment of the process METHOD: The author provides technical nuances and describe step by step the radical endoscopic hypophysectomy. The study of cadaveric specimens adds clarifying dissections. CONCLUSIONS: Radical hypophysectomy is an easily replicable and safe procedure. The most important morbidity is the intraoperative cerebrospinal fluid (CSF) leakage, which is inherent to this technique and can be successfully prevented with a pedicled nasoseptal flap reconstruction.