Lateral recess sphenoid sinus encephaloceles treated via transorbital neuroendoscopic surgery: illustrative case.

BACKGROUND: Lateral recess sphenoid sinus encephaloceles (LRSSEs) are considered a rare condition. Conventional surgical treatments include open approaches and endonasal endoscopy. These approaches are associated with approach-specific comorbidities. Alternatively, transorbital neuroendoscopy surgery (TONES) has been shown to provide a direct, minimally invasive approach to the middle fossa. Only a limited number of publications have reported using TONES as the primary surgical method for LRSSEs. OBSERVATIONS: A 57-year-old female presented to our hospital with a 1-month history of increased quantity and frequency of left nostril rhinorrhea and was found to have a left LRSSE. CT cisternography and MRI confirmed left temporal brain matter entering through the middle fossa floor into a well-pneumatized sphenoid sinus. The patient's LRSSE was successfully repaired using a lateral TONES approach. In addition, a systematic review conducted in accordance with PRISMA guidelines identified 9 patients from 7 studies spanning the years 2016 to 2025. LESSONS: This case illustrates that TONES provides a direct, minimally invasive corridor for the surgical treatment of LRSSEs, with minimal comorbidities. An ideally positioned LRSSEs might suggest that TONES is the most suitable choice. https://thejns.org/doi/10.3171/CASE26124.