Endoscopic Endonasal Transseptal Approach to the Contralateral Medial Orbital Region

 

Introduction: Several lateral, purely endoscopic, and combined approaches to the orbit have previously been described. Traditional external approaches, including the transconjunctival, transcranial, and lateral orbitotomy, have been associated with potential cosmetic morbidity. Additionally, they present a limitation accessing the orbit’ most medial segments. The use of the endoscopic endonasal trans-septal approach (EETSA) to access the contralateral parapharyngeal and infratemporal fosse was described and quantified. The utilization of this approach to access the contralateral medial orbital region has been reported but poorly quantified. The use of the EETSA as a single approach to access this region may present several advantages.

Objective: To study and compare the surgical corridor's freedom, area exposure, and extreme point angle of attacks obtained by purely simple EEA and EETSA to the contralateral medial orbital region.

Methods: Five cadaveric specimens (10 sides) were dissected and used for morphometric analysis. A simple EEA (simple posterior septectomy) followed by an EETSA (partial septal cartilage) to the contralateral medial orbital region was performed to avoid data overlapping. The area of exposure, surgical freedom, and angle of attack to the most extreme points was measured with neuronavigation assistance and compared. Additionally, an illustrative clinical case employing the EETSA was analyzed.

Results: The simple EEA and EETSA offer the benefits of minimally invasive access, including the lack of skin incision and brain or orbital retraction through the access. The EETSA, as expected, presents a significantly higher area of exposure and corridor’ surgical freedom than the simple EEA. Furthermore, the angle of attack was also higher in the EETSA than in simple EEA, but only in the horizontal plane. The EETSA improves the exposure, allowing safe handling of the tumor.

A surgical case demonstrating the advantages of the EETSA is analyzed. A 50-year-old male presented with an incidental unilateral proptosis of his right eye and normal vision. A left EETSA to the right medial orbital region was performed with a gross total resection of a schwannoma. No cosmetic or other comorbidities were described with twelve months of follow-up.

Conclusion: The purely EETSA to the contralateral orbital region represents a valuable technique in the skull base surgery armamentarium, counting with minimally invasive approaches advantages, and facilitating safe resection of orbital lesions, particularly those with an anterior extension.

Publication History

Article published online:
15 February 2022

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