Rapid ventricular pacing for flow arrest during cerebrovascular surgery: revival of an old concept.

BACKGROUND: Intraoperative rupture of a cerebral aneurysm can be a devastating event that increases operative morbidity and mortality. Rapid ventricular pacing (RVP) is a technique used in interventional cardiology to obtain flow arrest for short periods of time. OBJECTIVE: To present our experience using RVP for flow arrest during cerebrovascular surgery. METHODS: We used RVP to produce flow arrest for periods of 40 seconds in 12 patients who underwent craniotomy for a cerebrovascular disorder (11 aneurysms and 1 arteriovenous malformation). RESULTS: During RVP, there was an immediate and significant reduction of blood pressure in each patient. The maximum degree of hypotension was obtained 3.2 ± 0.7 seconds (mean ± SD) after the start of RVP. When RVP was terminated, normal sinus rhythm returned instantaneously, along with recovery of indexes of hemodynamic function. Subjectively, the decrease in blood pressures facilitated dissection, and during clipping, the aneurysm sac felt softer and was easier to manipulate. No complications related to RVP occurred. CONCLUSION: Rapid ventricular pacing during cerebrovascular surgery is an effective method for lowering the arterial blood pressure in a controlled and directly reversible manner. Advances in cardiology now make RVP a promising and safe technique that can facilitate complex cerebrovascular surgery.

A simple method for evaluating the quality of microvascular anastomoses performed in vitro.

OBJECTIVE: The aim of this paper is to describe a simple and effective method for evaluating the quality of microvascular anastomoses performed in vitro. METHODS: After the microvascular anastomosis has been performed in vitro, the vessel is cannulated at a distance of several millimeters from the anastomosis site with a catheter that is connected to a syringe filled with commercially available silicone glue. The silicone glue is slowly injected into the artery until the whole specimen is filled. Small leaks at the anastomosis site can be seen directly as the silicone glue will slowly extrude at the point of a leak. Then, the catheter is withdrawn and the specimen, filled with silicone, is left for several hours to solidify. Subsequently, the specimen is immersed in H(2)O(2) for several hours in order to dissolve the tissue from the silicone cast. In this manner, the cast of the silicone represents the virtual lumen of the blood vessel and the print of the lumen surface. RESULTS: Using this method, several important technical aspect of the anastomosis can be easily evaluated, such as diameter differences of the blood vessel, stricture, narrowing, irregularities of the vessel wall, leakage through the anastomotic site, and the alignment of the vessel walls. CONCLUSION: The silicone cast method as described in this study can be used to evaluate some technical aspect of a microvascular anastomosis performed in vitro. Moreover, it can be used to monitor the progress of the trainee and as an aid in improving and mastering vascular microsurgery.

Microsurgical removal of Onyx HD-500 from an aneurysm for relief of brainstem compression. Case report.

The authors report the successful removal of Onyx HD-500 from an aneurysm sac by means of ultrasonic aspiration. This 46-year-old woman presented with progressive spasms of her left arm and leg due to mass effect and compression on the right cerebral peduncle 5 years after endovascular treatment of an unruptured giant posterior communicating artery aneurysm with Onyx HD-500. No filling of the aneurysm was detected on angiography. The patient underwent a right pterional craniotomy and the aneurysm was opened to remove the Onyx mass. However, contrary to expectations, the aneurysm was still patent, filling with blood between the Onyx mass and the aneurysm wall. Under temporary clipping of the carotid artery, the Onyx mass within the aneurysm was removed in a piecemeal fashion using an ultrasonic aspirator and the aneurysm was then successfully clipped. The patient experienced significant improvement of the spasm after surgery. Angiography showed complete occlusion of the posterior communicating artery aneurysm. It is rarely necessary to remove embolization material such as Onyx HD-500, and little is known about the most appropriate surgical technique. This case report demonstrates that removal can be safely accomplished by means of ultrasonic aspiration.