Carotid microendarterectomy.

The illumination and magnification provided by the operating microscope allow for the accurate and complete removal of atherosclerotic plaque from the carotid arterial wall, for precise arterial repair at the distal end of the internal carotid endarterectomy, and for a fine, nonstenosing arteriotomy closure. A high dissection of the internal carotid artery, allowing arterial exposure above the plaque, is particularly helpful in the performance of carotid microendarterectomy. The technique of carotid microendarterectomy has been used in a consecutive series of 60 patients with symptomatic carotid stenosis, all but 5 of whom had carotid stenoses of 70% or more. In this series, there were no deaths and only one postoperative stroke, due to occlusion at the operative site. Emergency thrombectomy and angioplasty restored blood flow, and the patient recovered. In this and all other patients, carotid patency after surgery has been confirmed (angiography in 6 and Doppler examination in 54). Although postoperative stroke risk is dependent upon many factors, we feel that the refinements afforded by the operating microscope help reduce the risks associated with surgical technique to a minimum.

Gauze-induced granuloma ("gauzoma"): an uncommon complication of gauze reinforcement of berry aneurysms.

Incompletely and even adequately clipped berry aneurysms are often reinforced with finely shredded gauze. In seven female patients this practice led to a series of events including headache, pyrexia, seizures, cranial nerve deficits, endocrinopathy, cerebrospinal fluid pleocytosis, and an enhancing mass demonstrated by computerized tomography at the aneurysm site. One patient with blindness, hydrocephalus, and panhypopituitarism died and was examined at autopsy. Three additional female patients have been identified in the literature with similar case histories. It is suggested that in these patients the gauze induced a foreign-body granuloma, accompanied by progressive occlusion of neighboring small arteries. It would seem prudent to reserve gauze reinforcement for aneurysms that cannot be securely obliterated surgically.

A technique for rapid non-suture vascular anastomosis.

In an attempt to overcome some of the difficulties inherent in vascular anastomosis using standard suture methods, we have developed a technique that allows for rapid non-suture anastomosis of blood vessels. The technique has been used in over 400 anastomoses, including interposition vein grafts in rat, rabbit and dog vessels ranging in size from 0.7 mm to 3 mm in diameter. Animals have been followed for over 1 year postoperatively with serial angiography and histological evaluation including scanning electron microscopy. Stress studies have compared the biomechanical properties of both non-suture and suture anastomosis. The overall patency rate in non-suture end-to-end anastomoses using an interposition vein graft was 85% at 1 year follow up. Histological evaluation revealed a healing pattern that was temporally similar to that of the suture technique. Stress tests revealed no significant difference between suture and non-suture technique. These studies reveal that the non-suture technique compares favourably with the suture technique, and demonstrate the feasibility of applying this technique to man.

Effect of perioperative platelet inhibition on postcarotid endarterectomy mural thrombus formation. Results of a prospective randomized controlled trial using aspirin and dipyridamole in humans.

A prospective randomized double-blind trial was conducted to study the effect of platelet-inhibiting drugs on mural thrombus formation after carotid endarterectomy. Twenty-two patients undergoing carotid endarterectomy were randomly assigned to perioperative administration of an aspirin/dipyridamole combination or a placebo, and the postoperative results were compared. Autologous indium-111-labeled platelets were injected postoperatively, and platelet deposition was measured at the endarterectomy site. It was found that the treated group had a significant reduction in platelet accumulation compared with the placebo group. The results suggest that the perioperative use of aspirin/dipyridamole may reduce the risk of operative stroke and the long-term risk of repeat carotid stenosis.

Monitoring of sensory evoked potentials during surgery of skull base tumours.

Despite advances in instrumentation and the use of microsurgical techniques, neurosurgical procedures involving extensive areas of skull base or other critical areas of brain still carry significant risk for neurological injury. The use of intraoperative recording of sensory evoked potentials (SEP) has been advocated to monitor neurologic function during these major neurosurgical procedures to reduce the risk of injury to neural structures. This report summarizes our experience with intraoperative monitoring of SEP in over 200 patients, and details our findings in a group of 12 patients with skull base and posterior fossa tumours. Somatosensory evoked potentials (SSEP) were monitored in all patients, and brain stem auditory evoked potentials (BAEP) in five. While minor changes in BAEP and SSEP parameters were noted in most patients, significant changes occurred in five. Irreversible loss of BAEP in one patient was associated with complete hearing loss postoperatively. Marked, persistent alteration of both BAEP and SSEP was associated with postoperative brainstem dysfunction. No patient with stable BAEP and SSEP at the end of the procedure suffered additional neurological deficit. We conclude that intraoperative SEP monitoring may be valuable in minimizing neural injury during major neurosurgical procedures.

Thromboendarterectomy for total occlusion of the internal carotid artery: a reappraisal of risks, success rate and potential benefits.

Forty consecutive patients undergoing thromboendarterectomy for total internal carotid artery occlusion were studied in an attempt to determine a) whether careful case selection could be expected to reduce future postoperative mortality and morbidity, b) whether the achieved patency rate justified early operation and c) whether patients in whom patency was restored and maintained had a better long-term prognosis. The results show that a group of patients can be selected that will have low postoperative mortality and morbidity. The success rate for restoration of blood flow is high, particularly if the operation is performed soon after occlusion. The long-term prognosis in patients in whom patency of the internal carotid artery is restored and maintained appears to be better than in those with persistent occlusion of the carotid artery.