Background: Transorbital neuroendoscopic surgery (TONES) is a novel approach to address challenging skull base lesions that are poorly accessible via the transnasal approach due to their positioning or proximity to neurovascular structures. It allows for access to the orbit, anterior cranial fossa, middle cranial fossa, and lateral cavernous sinus. It has been utilized in recent years for specific skull base pathologies with success.
Objectives: The objective of this study is to describe our institution’s recent experience with TONES and analyze preliminary patient outcomes.
Methods: A retrospective chart review was performed of all patients who underwent TONES from January 1, 2017 through August 31, 2017 at the University of North Carolina Hospital. Demographic data, intraoperative details, intraoperative outcomes, and postoperative outcomes were assessed. Descriptive analysis was then performed.
Results: Five patients who underwent TONES were identified. Mean age at time of surgery was 43.2 ± 20.8 years. 60% of patients were female. Mean duration of follow-up was 50.5 ± 26.3 days. Pathologies were encephalocele (n=2), intracranial/intraorbital abscess (n=1), ossifying fibroma (n=1), and sinonasal squamous cell carcinoma (n=1). All five patients underwent a superior eyelid approach. For the patient with the intradural abscess, adequate visualization could not be obtained using TONES and a separate frontal craniotomy was performed. Two patients, one with a large encephalocele extending into the nasal cavity and the second with sinonasal squamous cell carcinoma extending into the orbit, required extension of the superior eyelid incision medially to a Lynch incision. Gross total resection was achieved in the four patients who underwent TONES without the need for a separate craniotomy. It was also achieved in the patient who required a separate frontal craniotomy. There were no intraoperative or postoperative cerebrospinal fluid (CSF) leaks. Two patients, including the patient who underwent a frontal craniotomy, reported postoperative diplopia and one of them also endorsed decreased sensation in the V1 distribution at follow-up. None of the patients endorsed vision loss or long-term diplopia. There were no cases of stroke or mortality.
Conclusion: TONES is a new surgical technique that provides access to certain skull base lesions. Its use has only been reported in select institutions. In this institution, TONES has led to gross total resection of skull base lesions in four patients without requiring a separate craniotomy. There have been no cases of intraoperative or postoperative CSF leaks. Out of the four patients who had complete resections with TONES, one had postoperative diplopia and none showed signs of cerebrovascular compromise. While these results are promising, future studies will be necessary to compare the outcomes of TONES with those of other approaches.