When might surgery be preferable to radiosurgery for abnormal blood vessels in the brain?

Details

The best management of brain arteriovenous malformations (bAVM) remains uncertain. The Spetzler-Martin grade (SMG), however, has been validated as an effective determinant of surgical risk. This systematic review sought the best evidence on bAVM management from case series that analyzed results by SMG.

The researchers searched Medline, Embase, Scopus and Cochrane for series from January 2000 to January 2018 that included at least 100 cases and stratified results by SMG. They selected series that divided treatment-complication outcomes at the boundary between modified Rankin Scale (mRS) scores of 1 and 2, or reported a favorable outcome (FO), defined as complete occlusion, no neurological deterioration and no post-treatment hemorrhage. Case series using population subsets defined by criteria other than SMG, or involving a prior history of hemorrhage, were excluded.

The outcomes examined were treatment complications causing a new permanent neurological deficit with an mRS score >1, termed an adverse outcome; post-treatment hemorrhage; occlusion rate; and FO. Where more than one treatment modality could be examined, the review compared surgery, radiosurgery, embolization or multiple treatment modalities within specific Spetzler-Ponce classes (SPC): A (SMG I and II), B (SMG III) and C (SMG IV and V).

The initial search found 116 papers. After reviewing publications and removing papers with duplicated patient outcomes, 11 publications met the analysis criteria: 5 exclusively surgical, 4 exclusively radiosurgical, 1 exclusively endovascular and 1 using multiple modalities.

The following outcome comparisons were statistically significant. For SPC A and B, respectively, FO rates were higher after surgery—98.6% (95% CI: 97.5–99.2%) and 76.4% (95% CI: 70.0–81.7%)—than after radiosurgery—70.8% (95% CI: 66.8–74.6%) and 61.0% (95% CI: 56.0–65.8%) (P<0.01).

For SPC A and B, respectively, the proportions of bAVM remaining unobliterated were lower after surgery—0.5% (95% CI: 0.2–1.4%) and 3.0% (95% CI: 1.4–5.8%)—than after radiosurgery—23.9% (95% CI: 20.4–27.8%) and 30.9% (95% CI: 27.9–34.0%). Surgery also had a lower unobliterated proportion than embolization in SPC A, for which the embolization figure was 7.6% (95% CI: 4.3–12.9%) (P<0.01).

In SPC B, adverse outcomes were more frequent after surgery, at 15.6% (95% CI: 11.8–20.0%), than after radiosurgery, at 3.3% (95% CI: 2.3–4.8%) (P<0.01). This significant difference was not found for SPC A. No analysis of SPC C was possible.

The authors concluded that surgery generally remains the best choice for SPC A bAVM. For SPC B, treatment choice should hinge on the likelihood of obliteration by radiosurgery; when that likelihood is high, radiosurgery should be preferred. The analysis provided insufficient information to recommend embolization for cure. For SPC C, there is no satisfactory standardized treatment, and treatment must remain individualized.