Endonasal Endoscopic Anatomy of the Orbito-Cavernous-Pterygopalatine Interface: Multilayer Anatomical Description and Landmarks to Define the Limits of the Compartments.

BACKGROUND: Despite growing interest in the endoscopic endonasal approach (EEA) to the medial orbital apex (OA), a comprehensive description of the multilayer topology lying at the intersection of the regional compartments is missing. METHODS: An EEA to the OA, pterygopalatine fossa, and cavernous sinus was performed in 20 specimens. A 360° layer-by-layer dissection was performed taking into consideration relevant anatomical aspects of the interface and documented with 3-dimensional technologies. Endoscopic landmarks were analyzed to provide an outline of the compartments and identify critical structures. Additionally, the consistency of a previously described reference called orbital apex convergence prominence was analyzed and a method to identify its position was introduced. RESULTS: The orbital apex convergence prominence was an inconsistent finding (15%). However, a craniometric method introduced in this study proved to be reliable to reach the orbital apex convergence point. Additional structures such as the sphenoethmoidal suture and a 3-suture junction (sphenoethmoidal-palatoethmoidal-palatosphenoidal) helped to identify the posterior limit of the OA and define a keyhole to access the compartments of the interface. We defined the bone limits of the "optic risk zone," an area where the optic nerve is more susceptible to damage. Furthermore, an orbital fusion line (periorbita-dura-periosteum) was identified and divided into 4 segments according to adjacent structures: optic, cavernous, pterygopalatine, and infraorbital. CONCLUSIONS: Understanding cranial landmarks and the folds of the layers covering the orbito-cavernous-pterygopalatine interface can facilitate tailoring an EEA to the medial orbital space and avoid unnecessary exposure of sensitive anatomy in the vicinity.

Morphometric Analysis of the Ophthalmic and Central Retinal Arteries via the Endoscopic Endonasal Trans-ethmoidal Approach: Surgical Relevance of Vascular Components Within the Medial Intraconal Zones.

BACKGROUND: The endoscopic endonasal approach (EEA) offers a minimally invasive route to treat medial intraconal space (MIS) lesions. Understanding the configuration of the ophthalmic artery (OphA) and the central retinal artery (CRA) is crucial. METHODS: An EEA to the MIS was performed on 30 orbits. The description of the intraorbital part of the OphA was divided into 3 segments and classified as type 1 and type 2 and the MIS was divided into three surgical zones (A, B, C). The CRA's origin, course, and point of penetration (PP) were analyzed. The relationship between the position of the CRA in the MIS and the OphA type was analyzed. RESULTS: The OphA type 2 was present in 20% of specimens. The site of origin of the CRA from the OphA was found on the medial surface in type 1 and on the lateral surface of type 2. The point of penetrationof the central retinal arterywas found in 87% of the specimens on the inferomedial surface, just anterior to the inferior muscular trunk, at an average distance of 9.5 mm ± 1 from the globe and 17 mm ± 1.5 from the AZ. The presence of the CRA in Zone C was associated only with OphA type 1. CONCLUSIONS: OphA type 2 is a common finding and can compromise the feasibility of an EEA to the MIS. A detailed preoperative analysis of the OphA and CRA should be conducted prior to approaching the MIS due to the implications of the anatomical variations that can compromise safe intraconal maneuverability during an EEA.

A Severe Case of Brain Myiasis: Treatment Rationale and Review of Literature.

Cerebral myiasis is a rare condition caused by a parasitic infestation of fly larvae feeding on the host's necrotic or living tissue. Only 16 cases of cerebral myiasis have been published. We presented the case of a 72-year-old man with a neglected infestation of an extensive ulcerative cancer of the scalp. A large cranial lesion, with exposed brain and dura mater and severe Sarcophaga carnaria maggot infestation, was evident. We gently removed the maggots and covered the defect with thick gauze and sodium hypochlorite solution dressing. We additionally present a review of the literature to highlight shared features and suggestions for care management. In all cases, there was an absence of fatal meningitis and encephalitis, which is surprising given the open skull erosion with prolonged cortical exposure and points to the protective effects of larvae wound infestation.