Use of a compact high-definition two-dimensional exoscope in surgical treatment of large vestibular schwannoma

Abstract

Background:Extra-corporeal video telescope operating monitor system provides a necessary instrument to perform high-precision neurosurgical procedures that could substitute or supplement the traditional surgical microscope. The present study was designed to evaluate a compact high-definition two-dimensional exoscope system for assisting in surgical removal of large vestibular schwannoma (VS), as an alternative to a binocular surgical microscope.Methods:Patients with Koos grade 3 and grade 4 VS undergoing surgery were enrolled in this prospective cohort study between January 2013 and June 2018. The demographics and tumor characteristics (size, Koos grade, composition [cystic or solid mass]) were matched between the two groups of patients. The following outcome measurements were compared between the two groups: duration of surgery, volume of blood loss, extent of tumor resection, number of operating field adjustments, pre- and post-operative facial and cochlear nerve function evaluated at 3 months post-surgery, complications and surgeons' comfortability.Results:A total of 81 patients received tumor resection through the retrosigmoid approach under either an exoscope (cases, n=39) or a surgical microscope (control, n=42). Patients in the two groups had comparable tumor location (P=0.439), Koos grading (P=0.867), and composition (P=0.891). While no significant differences in the duration of surgery (P=0.172), extent of tumor resection (P=0.858), facial function (P=0.838), and hearing ability (P=1.000), patients operated on under an exoscope had less blood loss (P=0.036) and a fewer field adjustments (P<0.001). Both primary and assistant surgeons reported a high level of comfort operating under the exoscope (P=0.001 and P<0.001, respectively).Conclusions:The compact high-definition two-dimensional exoscope system provides a safe and efficient means to assist in removing large VSs, as compared to a surgical microscope. After the acquaintance with a visual perception through a dynamic hint and stereoscopically viewing corresponding to the motion parallax, the exoscope system provided a comfortable, high-resolution visualization without compromising operational efficiency and patient safety.