Extracranial-intracranial bypass surgery at high magnification using a new high-resolution operating microscope: technical note

Background: We report a precise technique for EC-IC bypass surgery using a stereoscopic high-resolution microscope at magnifications of 40x and 50x. Methods: A stereoscopic operating microscope (Mitaka MM50 Surgical Microscope; Mitaka Kohoki Co, Tokyo, Japan) was used in STA-MCA anastomosis. This microscope has 2 optical systems, a standard zooming system, a newly developed high-magnification system, and 4 fixed working distances of 200, 250, 300 and 350 mm, with highest magnifications of 50.4x at 200 mm and 40.3x at 250 mm. High resolution is achieved by a new lens design in the optical system, which makes the image of the object very clear at high magnification. The magnification can be changed depending on the circumstances in a given procedure. The STA-MCA anastomoses were performed using this microscope. Results: Very small vessels were observable, and arterial anastomosis could be performed precisely at high magnification. All anastomoses were patent on postoperative angiograms. Conclusions: Use of the new microscope allows visualization and manipulation of small vessels at high magnification and high resolution and may be very useful in EC-IC bypass surgery. (C) 2009 Elsevier Inc. All rights reserved.