Short- and long-term results of microvascular anastomosis in the vertebrobasilar system, a critical analysis.

During the past five years, 22 patients were operated on and 21 occipital artery-caudal, loop-posterior, inferior cerebellar artery anastomoses were completed. All but one patient had suffered either TIAs of the vertebrobasilar system or brain stem stroke with complete or partial recovery. All the patients had significant atherosclerotic occlusive disease of both vertebral arteries and bilateral hypoplasia of the posterior communicating arteries. Three patients died shortly after surgery because of brain stem infarction and myocardial infarction. In one of these patients no anastomosis was performed. Two other patients also died 2.5 years after the operations because of a metastatic carcinoma and a stroke. Diplopia and cerebellar ataxia were developed in one patient and meningitis in another patient postoperatively with partial and complete recovery, respectively. Fifteen of the remaining 16 patients have either improved or remained the same. One patient has gotten worse. Sixteen patients had anastomosis, a patency rate of 87.5 percent. The blood flow of the occipital artery was measured intraoperatively following the completion of anastomosis in 5 patients. The mean blood flow varied between 15-80 ML/min. with an average of 46 ML/min. The neurological mortality and morbidity in this operation, in addition to the neurological condition of the patient prior to surgery, seem to be significantly related to the position of the patient during the surgery and how well his vital signs, especially blood pressure, are kept within normal limits. A lateral semiprone position, with the head and neck flexed and about 5 degrees above the heart level, seems to be a satisfactory position. With careful selection of the patients and the maintenance of normal vital signs, especially during surgery, good results can be obtained.