Microsurgery versus Stereotactic Radiosurgery for Treatment of Patients with Brain Arteriovenous Malformation: A Systematic Review and Meta-analysis

Introduction: Treatment decision-making for brain arteriovenous malformations (bAVMs) with microsurgery or stereotactic radiosurgery (SRS) is often controversial given the lack of a high level of evidence. This is the first systematic review and meta-analysis effort to bridge this gap.

Methods: Medline and PubMed were searched from inception to June 21, 2022. The primary outcomes were obliteration and follow-up hemorrhage, and secondary outcomes were permanent neurological deficit (PND), worsened modified Rankin scale (mRS), follow-up mRS>2, and mortality. The GRADE approach was used for grading the level of evidence.

Results: Eight studies were included, which yielded 817 patients, of which 432 (52.8%) and 385 (47.1%) patients underwent microsurgery and SRS, respectively. Two cohorts were comparable in age, sex, Spetzler-Martin grade, nidus size, location, and eloquence. The meta-analysis showed that in the microsurgery group the odds ratio (OR) of obliteration was higher (95% vs. 53%, OR=18.51[11.05, 31.01], p< 0.000001) and the hazard ratio (HR) of follow-up hemorrhage was lower (HR=0.47[0.23, 0.97], p=0.04). Furthermore, the meta-analysis showed that the OR of PND was higher within the microsurgery cohort (14.6% vs. 5.3%, OR=2.85[1.63, 4.97], p=0.0002), while the OR of worsened mRS (14% vs. 12%, OR=1.24[0.65, 2.38], p=0.52), follow-up mRS>2 (15% vs. 12%, OR=0.78[0.36, 1.7], p=0.53), and mortality (2.9% vs. 1.5%, OR=1.17[0.41, 3.3], p=0.77) were comparable between the groups. The certainty of the evidence was high and moderate for primary and secondary outcomes, respectively.

Conclusion : Surgical intervention was superior at obliterating bAVMs and preventing further hemorrhage. Despite a higher rate of the postoperative neurologic deficit with microsurgery, functional status and mortality were comparable to patients who underwent SRS. Surgical intervention should remain the first-line consideration for bAVMs, with SRS reserved for inaccessible locations, highly eloquent areas, and medically high-risk or unwilling patients.