Endoscopic Transorbital Surgery for Middle Cranial Fossa Tumors

Objective: Although endoscopic endonasal approach for the skull base lesion recently has been evolved, it is still difficult to access to the middle cranial fossa including the petrous apex. That reason is why transcranial approaches (TCA) have been used to manage pathologies in these anatomic spaces. Recently, purely endoscopic transorbital surgery (ETOS) has been emerging as an alternative surgical approach for the lateral aspect of the skull base. We aimed to share experiences of ETOS.

Method: We started ETOS in June 2017 and collected data from patients who had undergone ETOS. And preoperative and postoperative magnetic resonance imaging (MRI), gross-total removal (GTR) rate, operative time, intraoperative blood loss, hospital stay, surgical morbidities were obtained. Post-op wound pictures were taken when they visited out-patient department.

Results: Ten patients underwent ETOS surgery until June 2018. One of them was combined with endoscopic endonasal approach. Upper eyelid incision and dissection to orbital margin was performed by a plastic surgeon. There were eight patients with meningioma, one patient with trigeminal schwannoma and one patient with plasma cell tumor. The mean tumor size was 3.4 cm. Gross-total removal of tumor was achieved in 7 patients (70%). Mean operation time was 4 hours 12 minutes. Mean intraoperative blood loss was 758 cc. Mean hospital days was 12 days. One patient experienced cerebrospinal fluid leakage as surgical morbidity and improved after lumbar puncture.

Conclusion: ETOS is considerable options for the lateral aspect of the skull base due to its less destructive, shorter operation time, fewer amount of intraoperative blood loss, faster recovery after surgery, and unremarked scar. As the number of ETOS cases increases, the indication of ETOS will be extending. However, there are lack of long-term follow-up and narrowing surgical field, so careful patient selection is necessary.