Nizzola, Mariagrazia

Purpose of review The purpose of this review is to provide a comprehensive anatomical appraisal of the neurosurgical anatomy exposed through the endonasal and paranasal sinuses routes, focusing on the most common expanded endonasal approaches (EEAs) as well as recent advances in this surgical field. Recent findings The EEAs are redefining the management of skull base pathology. Neurovascular structures previously considered a limitation, can be now approached through these surgical corridors. Advances in this field include the development of new surgical techniques and routes that allow better visualization and access to pathologies located in the ventral skull base. Understanding the surgical anatomy related to EEAs is essential not only for neurosurgeons but also for rhinologists. Summary Knowledge of the surgical anatomy of the most common EEAs that utilize paranasal sinuses as a surgical corridor enables more effective management of complex skull base pathologies. Comprehensive anatomical knowledge of these corridors and the surrounding neurovascular structures is crucial to maximize benefits of EEAs and improve outcomes.

Background: The transorbital approaches (TOAs) have acquired growing notoriety, thanks to their ability to offer alternative corridors to the skull base. However, the limited access and the unfamiliarity with this surgical perspective make recognition of key landmarks difficult, especially for less experienced surgeons. The study wants to offer a detailed description of the anatomy to comprehend the potential and limitations of TOAs. Methods: Measurements of the orbit region and the surrounding areas were performed on two hundred high-resolution CT scans and thirty-nine dry skulls. Five specimens were dissected to illustrate the TOA, and one was used to perform the extradural clinoidectomy. Three clinical cases highlighted the surgical applications. Results: A step-by-step description of the key steps of the TOA was proposed and a comparison with the transcranial anterior clinoidectomy was discussed. The mean work distance was 6.1 ± 0.4 cm, and the lateral working angle increased 20 ± 5.4° after removing the lateral orbital rim. Conclusions: TOAs are indicated in selected cases when tumor involves the lateral portion of the cavernous sinus or the middle skull base, obtaining a direct decompression of the optic nerve and avoiding excessive manipulation of the neurovascular structures. Comprehension of surgical anatomy of the orbit and its surrounding structures is essential to safely perform these approaches.