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The meningo-orbital band (MOB) is the most superficial dural band that tethers the fronto-temporal dura to the periorbita. It is usually encountered when performing a pterional or fronto-temporo-sphenoidal approach, and it disrupts surgical access to deeper regions. Our objective was to perform a detailed anatomy study and a stepwise method to successfully detach the MOB using cadaveric specimens. We used six formalin-fixed, silicone-injected cadaveric heads. On each side, we performed a pterional approach plus mini-peeling of the anterior third of the middle fossa and/or extradural anterior clinoidectomy. We also applied this technique in three clinical cases to prove its safety and efficacy. The detachment of the MOB consists in four steps, 1) detachment of the temporal and frontal dura, 2) cutting of the MOB, 3) exposure and drilling of the anterior clinoid process, and 4) pealing of the lateral wall of the cavernous sinus. Using clinical cases, we explain how to adapt the technique depending on the localization of the lesion. The detachment of the MOB is the key to safely expose the cavernous sinus and the anterior clinoid process. The authors proposed a step-by-step method for the safe and effective detachment of the MOB. It is recommended, particularly to less experienced neurosurgeons that are starting with skull base surgery, and also to experts that want to expand their knowledge.

Purpose: Cavernous sinus syndrome is a rare phenomenon, characterized by simultaneous neuropathies of cranial nerves III–VI. Various pathological processes have been reported as precipitating etiologies, including infection, inflammation, vascular lesions, and neoplasms. Purpose: We report a unique case series of cavernous sinus syndrome attributable to prolonged Trendelenburg or prone positioning during non-cranial procedures and review the pertinent literature to enlighten on this rare but catastrophic phenomenon. Methods: Retrospective case series. Results: In the past year we encountered two patients who presented with acute cavernous sinus syndrome upon awakening from non-cranial operations. One patient underwent an extensive urologic resection of a bladder malignancy positioned in Trendelenburg for approximately 4h. The second patient underwent a lumbar laminectomy and discectomy in prone position. Both patients were discovered to have infarcted large pituitary macroadenomas as the etiology of their acute ophthalmoplegias, and transnasal, transsphenoidal resection was performed acutely to decompress the cavernous sinus contents. Pathologic analysis of the resected specimens in each case confirmed necrotic, infarcted pituitary adenoma. Both patients made a complete recovery with no evidence of residual or recurrent tumor in short term follow-up. Conclusion: We report a brief case series of acute cavernous sinus syndrome resulting from dependent positioning during non-cranial operations in patients with pituitary macroadenoma. Although rare, this highlights a potential danger of “head down” positioning in patients with intracranial pathology—particularly in or around the sella and cavernous sinus. Despite multiple cranial neuropathies upon presentation, both patients made complete recovery following surgical decompression of the cavernous sinuses.

Multiple carotid cavernous fistula (CCF) classifications have been proposed. However, they lacked predictive factors for the clinical presentation, natural history, and hemorrhagic risk. Our aim was to externally validate a new classification according to venous drainage (i.e., the Thomas classification [TC]) to assess its relationship with symptoms, endovascular treatment, and outcomes.We performed a multicenter retrospective review of CCFs at 2 major academic institutions. The CCFs were classified using the Barrow classification (BC) and TC systems.The data from 94 patients with a diagnosis of CCF were collected during a study period 23 years, 4 months. Of these 94 patients, 89 had undergone CCF treatment and 5 had experienced spontaneous occlusion. Complete occlusion was achieved in 89.9% of the treated patients. Complications occurred in 5.3% of the patients, including permanent deficits in 2.1%. TC type 4 was associated with cortical symptoms compared with type 2 (P = 0.003) and type 3 (P0.001). The BC was not able to detect significant differences among the symptom types. Significant differences were found using the TC for the transarterial-only, transvenous anterior-only, and transvenous posterior-only approaches (P0.001, P = 0.03, and P = 0.001, respectively). The transvenous posterior and transvenous anterior approach were significantly associated with type 2 and 3 TC, respectively. Excluding direct CCFs, the BC was not related to the treatment approach. No significant differences in the outcomes were found. However, a trend toward a lower occlusion rate for TC type 4 compared with type 3 was observed.The TC provided useful information regarding the fistula anatomy and venous hemodynamics, which correlated with the clinical symptoms and treatment strategy.

OBJECTIVEExposure of the cavernous sinus is technically challenging. The most common surgical approaches use well-known variations of the standard frontotemporal craniotomy. In this paper the authors describe a novel ventral route that enters the lateral wall of the cavernous sinus through an interdural corridor that includes the removal of the greater sphenoid wing via a purely endoscopic transorbital pathway.METHODSFive human cadaveric heads (10 sides) were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. To expose the lateral wall of the cavernous sinus, a superior eyelid endoscopic transorbital approach was performed and the anterior portion of the greater sphenoid wing was removed. The meningo-orbital band was exposed as the key starting point for revealing the cavernous sinus and its contents in a minimally invasive interdural fashion.RESULTSThis endoscopic transorbital approach, with partial removal of the greater sphenoid wing followed by a “natural” ventral interdural dissection of the meningo-orbital band, allowed exposure of the entire lateral wall of the cavernous sinus up to the plexiform portion of the trigeminal root and the petrous bone posteriorly and the foramen spinosum, with the middle meningeal artery, laterally.CONCLUSIONSThe purely endoscopic transorbital approach through the meningo-orbital band provides a direct view of the cavernous sinus through a simple and rapid means of access. Indeed, this interdural pathway lies in the same sagittal plane as the lateral wall of the cavernous sinus. Advantages include a favorable angle of attack, minimal brain retraction, and the possibility for dissection through the interdural space without entering the neurovascular compartment of the cavernous sinus. Surgical series are needed to demonstrate any clinical advantages and disadvantages of this novel route.