Orbital Rim Removal in Endoscopic Transorbital Approaches: Unveiling Indications and Technical Nuances

Area of Science:

• Neurosurgery
• Surgical Oncology
• Anatomy

Background:

• Endoscopic transorbital approach (ETOA) is a minimally invasive technique for accessing skull base pathologies.
• Orbital rim removal (ORR) is a modification of ETOA that may improve surgical access.
• Indications and outcomes of ORR within ETOA require further elucidation.

Purpose of the Study:

• To define the indications and technical aspects of orbital rim removal (ORR) during endoscopic transorbital approach (ETOA).
• To compare clinical outcomes between patients undergoing ETOA with and without ORR.
• To introduce a novel anatomical landmark, the sphenoarcuate line (SpAL), for surgical planning.

Main Methods:

• Retrospective analysis of 121 patients who underwent ETOA between August 2016 and October 2023.
• Anatomical study using 3 cadaveric specimens and 3D photogrammetry to demonstrate the ORR technique.
• Introduction and validation of the sphenoarcuate line (SpAL) as a surgical planning metric.

Main Results:

• ORR was performed in 54 patients (44.6%). Overall good outcomes (gross total or near-total resection) were achieved in 74.3% of patients.
• No significant difference in good outcome rates between ORR (73.1%) and non-ORR (75.9%) groups.
• ORR significantly improved good outcome rates for meningiomas (P=.04) and tumors extending laterally beyond the SpAL (P=.03).
• 3D photogrammetry confirmed significant expansion of surgical exposure after ORR.

Conclusions:

• Orbital rim removal (ORR) is a valuable technique that expands surgical exposure in the endoscopic transorbital approach (ETOA).
• ORR significantly improves outcomes for specific tumor types, including meningiomas and laterally extending lesions.
• The combination of clinical data and anatomical studies supports ORR as an important tool for complex transorbital surgeries.