MICROSURGICAL TREATMENT OF ARTERIOVENOUS-MALFORMATIONS - ANALYSIS ANDCOMPARISON WITH STEREOTAXIC RADIOSURGERY

Object. To compare microsurgical and stereotactic radiosurgical treatm ent of arteriovenous malformations (AVMs), the authors analyzed a pros pective series of 72 consecutive patients who were treated microsurgic ally for cerebral AVMs by one neurosurgeon. The authors then compared the results of microsurgical treatment with published results of stere otactic radiosurgical treatment of small AVMs. Methods. Patients were categorized by age, gender, presentation, and preoperative neurologica l status. The AVMs were categorized by size, location, presence of dee p venous drainage, and Spetzler-Martin grade. Outcome was assessed for angiographic obliteration, hemorrhage following treatment, presence o f a new, persistent postoperative neurological deficit, and Glasgow Ou tcome Scale (GOS) score. Ordinal logistic regression was used to model the GOS score and to predict new postoperative deficits. Generalized estimating equations were used to compare published results of microsu rgical and stereotactic radiosurgical treatment of AVMs. Kaplan-Meier event-free survival plots were generated to compare the two modalities with respect to hemorrhage following treatment. Overall, six patients (8.3%) exhibited a new persistent neurological deficit postoperativel y. Sixty-five patients (90.3%) had a GOS score of 5. Three patients we re moderately disabled and four patients were severely disabled. No pa tient was observed to be in a vegetative state and there were no treat ment-related deaths. Seventy-one patients (98.6%) underwent intra-or p ostoperative angiography. Total excision of the AVM was angiographical ly confirmed in 70 patients (98.6% of those who underwent angiography) . To date no patient has suffered from hemorrhage since the microsurgi cal treatment. When analysis was confined to patients whose AVMs were smaller than 3 cm in maximum diameter, the authors found a 100% angiog raphic obliteration rate, no new postoperative neurological deficit, a nd a good recovery in all patients. An analysis of all patients with S petzler-Martin Grades I to III resulted in a 100% rate of angiographic obliteration, one patient with a new postoperative neurological defic it, and good recovery in 93% of the patients. Size of the AVM, preoper ative neurological status, and patient age are associated with GOS sco re (for all, p < 0.02). The Spetzler-Martin grading system as well as each component of this system are associated with the development of a new postoperative neurological deficit (for all, p < 0.01). For the e ntire series there were fewer postoperative hemorrhages and deaths tha n those mentioned in published series of small AVMs treated with stere otactic radiosurgery. When these patients and published series of pati ents with microsurgically treated AVMs classified as Grade I to III we re compared with similar patients treated radiosurgically there were s ignificantly fewer postoperative hemorrhages (odds ratio = 0.210, p = 0.001), fewer deaths (odds ratio = 0.659, p = 0.019), fewer new posttr eatment neurological deficits (odds ratio = 0.464, p = 0.013), and a h igher incidence of obliteration (odds ratio = 28.2, p = 0.001) for the microsurgical group. Lifetable analysis confirms the statistically si gnificant difference in hemorrhage-free survival time between the two groups (p = 0.002). Conclusions. Based on this analysis, microsurgical treatment of Grades I to III AVMs is superior to stereotactic radiosu rgery.