Transorbital endoscopic approaches to the skull base: current concepts and future perspectives.

INTRODUCTION: Transorbital endoscopic surgery is one of the most recent fields of skull base surgery. This paper presents the emerging applications of transorbital endoscopic approaches to the skull base and their current results on the treatment of selected extradural and intradural lesions, based on a review of meta-analysis and recent clinical series.

EVIDENCE ACQUISITION: A PubMed, Cochrane and Ovid search for articles published from 2000 to 2015 was performed using the search terms "endoscopic skull base surgery", "transorbital endoscopic approach", and "transorbital neuroendoscopic surgery". No anatomical or preclinical studies were included in the present review. Among the clinical case series available, only those describing transorbital approaches to the skull base have been considered, excluding from the analysis the studies addressing the orbit and orbital pathologies.

EVIDENCE SYNTHESIS: Although performed in extremely selected cases, there is a growing body of evidence suggesting that this technique may be effective for the treatment of cerebrospinal fluid leaks, for the drainage of epidural abscess or hematoma, and for the removal of several skull base tumors such as spheno-orbital meningioma. For the treatment of intradural pathologies there is only anecdotal evidence suggesting effectiveness and safety. Factors that may contribute to the enhanced efficacy compared to traditional external approaches were the acceptable complication rates, the reduced hospitalization time and limited morbidity for the patients, avoiding the need for large external craniotomies and brain retraction.

CONCLUSIONS: Minimally-invasive endoscopic skull base surgery has substantially evolved in the last decades through the collaboration of different teams around the world. The transorbital endoscopic approaches directed to the anterior and middle cranial base may represent safe and feasible techniques with great potential for new applications in the nearby future.