# Contralateral mononostril endoscopic chopsticks technique for an intracavernous epidermoid cyst. Technical case report and systematic review of the literature

## TL;DR

A new minimally invasive endoscopic technique is used to treat a rare brain cyst, offering a safer alternative with good outcomes.

## Contribution

The contralateral mononostril endoscopic chopsticks technique is introduced as a novel surgical approach for intracavernous epidermoid cysts.

## Key findings

- The ECsT approach achieved complete cyst content removal with minimal morbidity in a 23-year-old patient.
- Partial capsule resection was performed due to adherence to neurovascular structures, with no recurrence at one year.
- A systematic review found transcranial approaches used in 92.5% of cases, with partial capsule resection in 58.5%.

## Abstract

Pure intracavernous epidermoid cysts (pIECs) are rare pathologies developing within the cavernous sinus (CS), typically displacing the internal carotid artery medially and cranial nerves laterally. When symptomatic, surgical treatment is indicated, and the approach must be tailored to anatomy.

Which surgical approach best balances morbidity with the complex anatomy of the CS in pIECs, and can anatomical classification guide surgical planning?

We report the resection of a left pIEC via a contralateral mononostril endoscopic endonasal approach using the Endoscopic Chopsticks Technique (ECsT). A systematic review of the literature was conducted to contextualize the case.

A 23-year-old man with progressive left oculomotor nerve palsy due to a pIEC underwent contralateral mononostril endoscopic surgery using the ECsT. Complete cyst content removal with partial capsule resection was achieved because of adherence to CS neurovascular structures. Sphenoid sinus cranialization and rostral mucosal suture were performed. The postoperative course was uneventful, with recovery of oculomotor deficit and no recurrence at one year. This represents the sixth reported case of a pIEC. The literature review identified 53 cases from 18 articles: transcranial approaches were used in 92.5% of cases, extended endonasal and transorbital approaches in 3.8% each. Partial capsule resection was performed in 58.5% of cases and in 66.6% of pIECs.

Epidermoid cysts of the CS should be treated when symptomatic, with surgical strategy guided by anatomical classification. In selected pIECs, a contralateral mononostril ECsT offers a minimally invasive option that minimizes morbidity while ensuring effective cyst control.

•Pure intracavernous epidermoid cysts represent an extremely rare surgical entity.•Anatomical classification is key to anticipate nerve displacement and guide the surgical approach.•Contralateral mononostril ECsT enables target access with minimal endonasal morbidity.•Total resection is often unsafe; planned subtotal capsule resection may be preferable.

Pure intracavernous epidermoid cysts represent an extremely rare surgical entity.

Anatomical classification is key to anticipate nerve displacement and guide the surgical approach.

Contralateral mononostril ECsT enables target access with minimal endonasal morbidity.

Total resection is often unsafe; planned subtotal capsule resection may be preferable.