Biportal Endoscopic TransOrbital and transMaxillary Approach to the Cranio-Orbital Region and Middle Cranial Fossa: A Preliminary Analysis of Maneuverability.

BACKGROUND AND OBJECTIVES: Traditional and well-established transcranial approaches to the spheno-orbital region and middle cranial fossa guarantee optimal intracranial exposure, and additional orbital and zygomatic osteotomies provide further control over extracranial components to be resected; however, these techniques come at the cost of additional morbidity. The introduction of minimally invasive endoscopic approaches and the conceptualization of the so-called "multiportal" paradigm might provide an alternative route. This preliminary study investigates the feasibility of the combined Biportal Endoscopic TransOrbital and transMaxillary Approach (bETOMA) approach to the spheno-orbital and middle cranial fossa regions. METHODS: Using 4 silicon-injected adult cadaver heads (8 sides; 16 approaches), we systematically dissected through superior eyelid ETOA and endoscopic TMA approaches. The analysis focused on pterygopalatine, infratemporal, anterior and middle cranial fossae, Meckel cave, and cavernous sinus access. We evaluated the feasibility of bETOMA using linear distances, angles of attack, and exposure areas. We also introduced volume of operative maneuverability, its standardized derivative (sVOM), target distance, visuo-operative angle, and working zone volume as novel metrics. RESULTS: The analysis revealed comparable angles of attack between approaches. ETOA and TMA exposure areas were 918.38 ± 223.93 mm2 and 257.07 ± 86.07 mm2, respectively. TMA showed a larger VOM in the greater sphenoid wing, but ETOA offered superior distal maneuverability (sVOM: 5.39 ± 1.94 vs 2.54 ± 0.79 cm3) and closer intracranial space access (27.45 vs 50.83 mm). The combined approaches yielded a mean working zone volume of 13.75 ± 3.73 cm3 in the spheno-orbital interface. CONCLUSION: The bETOMA approach provides adequate neurovascular exposure and maneuverability to the spheno-orbital region, infratemporal, and anterior and middle cranial fossae, addressing significant limitations of previously investigated monoportal techniques (ie, optic nerve decompression, hyperostotic bone resection, and infratemporal exposure). This combined minimally invasive approach might help manage lesions harbored within the cranio-orbital interface region invading the extracranial space.

Exoscopic supracerebellar approach to the pineal region.

The advent of the 3D exoscope represents a significant technological breakthrough in contemporary surgical practice. While the operating microscope has long been the preferred surgical visualization tool, its limitations in accessibility and ergonomics have prompted the development of a more advanced, 3D version [1,2]. The 3D exoscope has been one such recent development aimed at addressing these limitations. By delivering intense illumination and magnification to the deepest parts of the surgical field, 3D exoscopes are high-definition digital camera systems that give surgeons high-magnification views of the operative field [2]. Additionally, the design of the 3D exoscope allows for improved surgeon ergonomics, decreasing overall fatigue while providing a similar view of the procedure for all personnel in the operating room [3,4]. In this article, we discuss the advantages and limitations of the 3D exoscope in neurosurgery and highlight its use in a patient case. This is a case of a 25-year old female who was noted to have an incidental 13 mm pineal cystic mass on imaging work up for a first time generalized seizure. We discuss the use of an exoscopic supracerebellar approach to the pineal gland for resection of the mass and highlight the various considerations for use of an exoscope in such a case.

Surgical anatomy and technical nuances of the endoscopic endonasal approach to the anterior cranial fossa.

Endoscopic endonasal approaches (EEA) to the skull base have significantly impacted the management of lesions located in the cranial base. Specifically, lesions arising from the anterior cranial fossa, such as pituitary macroadenomas, craniopharyngiomas meningiomas and craniofacial malignancies have benefited from the development of such approaches. Understanding of the anatomy of the anterior fossa is of utmost importance for the successful selection of the approach and application of surgical techniques in EEA. In the current manuscript, we review the most relevant points of surgical anatomy and nuances of the surgical technique of EEA to the anterior fossa. Anatomical landmarks for the transtuberculum transplanum and transcribriform approaches are discussed and a step-by-step description for those approaches is presented. We reinforce that safe and effective application of such techniques follow the same principles of other skull base surgery techniques: mastering of surgical anatomy, adequate case selection, correct instrumentation and surgical experience.