Preliminary Experience with the use of a 3-Dimensional Exoscope for Excision of Unruptured Brain Arteriovenous Malformations: Case Series and Comparative Analysis.

Objective: To assess the use of a 3-dimensional exoscope in the resection of unruptured brain arteriovenous malformations (AVMs).

Methods: Unruptured brain AVMs resected by a single surgeon using 3-dimensional exoscope ORBEYE (Olympus-Tokyo-Japan) were compared with AVMs (matched for size and Spetzler-Martin [SM] grade) resected using the operating microscope (OM), prospectively collected over more than 2 years.

Results: 14 patients (7 females) with AVMs resected using the exoscope formed a case series and were compared with 21 patients (7 females) operated using the OM. All AVMs were SM grades 1 and 2. Median nidus size was 2.5 cm both in the exoscope (interquartile range [IQR]: 1.7-2.8) and the OM (IQR: 2-3) groups. Preoperative embolization was not used. There were no conversions to the microscope for the exoscope group. Median operating time was 136 minutes (IQR: 89-175) and 235 minutes (IQR: 135-295) (P = 0.02) for the exoscope and OM groups, respectively. Median blood loss was 75 mls (IQR: 50-200) and 200 mls (IQR: 127-300) (P = 0.04) for the exoscope and OM groups, respectively. There were 3 and 4 patients with temporary neurological deficits in the exoscope and OM groups, respectively. In either group, there were no postoperative deaths and no permanent neurological deficits. Postoperative digital subtraction angiography confirmed complete AVM excision in all cases. All patients were discharged home.

Conclusions: Surgery for unruptured low-grade brain AVMs can be performed safely using an exoscope with clinical and radiographic outcomes comparable to the OM. In this small series, the use of an exoscope was associated with shorter operative times and lower blood loss compared to the OM, in unruptured brain AVMs matched for size and SM grade.