Integration of ultrasonography and endoscopy into transsphenoidal surgery with a "picture-in-picture" viewing system--technical note.

Abstract

A technique to integrate ultrasonography and endoscopy is described for transsphenoidal surgery to prevent intraoperative internal carotid artery (ICA)-related, life-threatening complications such as aneurysmal formation and carotid-cavernous fistula. The ultrasound unit helps avoid direct injury to the ICA. The technical advantage of this system is the miniature 1-mm diameter microvascular probe, which does not disturb the operative field. An arterial or venous flow source of even an invisible vessel can be detected easily, noninvasively, and reproducibly. Real-time information with a 100% detection rate for the ICA is helpful for predicting localization even in the intracavernous portion, where the ICA is invisible. The endoscope unit can visualize the dead angle areas of the operating microscope by varying the endoscopic gateways and display on a "picture-in-picture" system. The advantage of both devices is the integration with a video processor, so that the real-time information from each unit can be switched intraoperatively onto the display as required. This method is of particular help for removing lesions with intracavernous invasion or encasement of the ICA.