Incidence of residual intracranial AVMs after surgical resection and efficacy of immediate surgical re-exploration

Background. The true incidence of residual lesions after surgical resection of AVMs is not well documented in the literature. Partial surgical resection is thought to not confer any improvement over the natural history risk of hemorrhage of AVMs, and in certain cases may actually increase the risk of hemorrhage. Over the past 11 years, we have adopted a policy of immediate postoperative angiography with immediate surgical re-exploration if a residual lesion is seen. The purpose of the present study was to review our experience to determine the incidence of residual lesions and subsequent outcome. Methods. From June 1991 to June 2002, 324 patients underwent craniotomy and surgical AVM resection. As per protocol, all patients underwent immediate postoperative angiography. We have a protocol for immediate surgical re-exploration if a residual lesion is seen on postoperative angiographic exam. Findings. There were total six patients (1.8% of patients operated with intracranial AVMs) with residual lesions on postoperative angiography. All six patients underwent immediate surgical re-exploration with complete 100% obliteration; two patients required two re-exploration procedures. There was one operative complication: posterior cerebral artery and superior cerebellar artery infarcts after re-exploration of residual lesion after surgical resection of a large occipito-temperal-parietal AVM. There were no other morbidities and no mortalities. Conclusions. The incidence of residual lesions seen on postoperative angiography after AVM surgery at an experienced center is 1.8%. Because of the potential imminent danger of hemorrhage from a residual lesion, we recommend a policy of immediate postoperative angiography (or intraoperative angiography if image quality is satisfactory) for all AVM surgery and early surgical re-exploration if a residual lesion is seen.