Application of the Endoscopic Micro-Inspection Tool QEVO® in the Surgical Treatment of Anterior Circulation Aneurysms—A Technical Note and Case Series

The authors prospectively compared a new technique of surgical microscope-based indocyanine green (ICG) videoangiography with intraoperative or postoperative digital subtraction (DS) angiography. The technique was performed during 187 surgical procedures in which 124 aneurysms in 114 patients were clipped. Using a newly developed setup, the ICG technique has been integrated into an operating microscope (Carl Zeiss Co., Oberkochen, Germany). A microscope-integrated light source containing infrared excitation light illuminates the operating field. The dye is injected intravenously into the patient, and intravascular fluorescence from within the blood vessels is imaged using a video camera attached to the microscope. The patency of parent, branching, and perforating arteries and documentation of clip occlusion of the aneurysm as shown by ICG videoangiography were compared with intraoperative or postoperative findings on DS angiography. The results of ICG videoangiography corresponded with intra- or postoperative DS angiography in 90% of cases. The ICG technique missed mild but hemodynamically irrelevant stenosis that was evident on DS angiography in 7.3% of cases. The ICG technique missed angiographically relevant findings in three cases (one hemodynamically relevant stenosis and two residual aneurysm necks [2.7% of cases]). In two cases the missed findings were clinically and surgically inconsequential; in the third case, a 4-mm residual neck may require a second procedure. Indocyanine green videoangiography provided significant information for the surgeon in 9% of cases, most of which led to clip correction. Microscope-based ICG videoangiography is simple and provides real-time information about the patency of vessels of all sizes and about the aneurysm sac. This technique may be useful during routine aneurysm surgery as an independent form of angiography or as an adjunct to intra- or postoperative DS angiography.

To evaluate the orbitopterional approach to anterior communicating artery (AComA) aneurysms, on the basis of the quantification of this surgical exposure, compared with the pterional approach, in a cadaveric study and a retrospective review of data for 40 patients who underwent clipping of AComA aneurysms via the orbitopterional approach. In an anatomic study, four cadaveric heads underwent pterional craniotomies on the left side and orbitopterional craniotomies on the right side. A fifth head was initially subjected to bilateral pterional craniotomies and then underwent bilateral orbital osteotomies, for direct comparison of these approaches. Using frameless stereotaxy, we quantified the angles of exposure and surgical field depths provided by the pterional and orbitopterional craniotomies. In a clinical study, 40 patients who underwent clipping of AComA aneurysms via orbitopterional approaches were evaluated for basal brain injury, the need for resection of the gyrus rectus, dissection of the sylvian fissure, and approach-related complications. The incidence of postoperative hydrocephalus among patients with subarachnoid hemorrhage who underwent lamina terminalis fenestration was also reviewed. The angles of observation were increased 46% in the axial plane (orbitopterional, 72.92 +/- 6.57 degrees; pterional, 49.75 +/- 2.27 degrees; P < 0.01) and 137.5% in the projection plane (orbitopterional, 8 +/- 2.19 degrees; pterional, 19 +/- 1.78 degrees; P < 0.01). The surgical window depth was decreased 13% with the orbitopterional approach (P < 0.05). Clinically, there was no incidence of frontobasal hypodensities on postoperative computed tomographic scans. Three patients (7.5%) required resection of the gyrus rectus. No patient required sylvian fissure dissection for aneurysm exposure. Two of 29 patients (6.9%) who survived subarachnoid hemorrhage required ventriculoperitoneal shunts despite lamina terminalis fenestration. No approach-related complications were recognized. The orbitopterional approach improved the observation of the AComA complex and seemed to decrease the risk of intraoperative brain damage.

Endoscope-assisted microneurosurgery (EAM) combines endoscopic and microsurgical techniques for the treatment of deeply located intracranial lesions. During aneurysm surgery, endoscopic assistance may aid in the visualization of perforating arteries, especially when minimally invasive approaches are used. Between 2002 and 2015, a total of 183 patients with 208 intracranial aneurysms were surgically treated in our department. EAM was performed in 191 procedures. In all, 159 aneurysms were located in the anterior circulation and 49 in the posterior circulation. Of these, 135 aneurysms were ruptured. Lesions were exposed through standard skull base microsurgical approaches. The endoscope was employed during three steps: initial inspection, true operative time, and final inspection. Complications directly related to endoscopic procedures were rare; no surgical mortality was observed in this series. A retrospective analysis of each procedure showed that the usefulness of EAM depended on the anatomical location and size of the lesions. Its advantages were especially evident when dedicated scopes and holders were used.