Validation of the supplemented Spetzler-martin grading system for brain Arteriovenous malformations in a Multicenter cohort of 1009 surgical patients

Helen Kim, Adib A. Abla, Jeffrey Nelson, Charles E. McCulloch, David Bervini, Michael K. Morgan, Christopher Stapleton, Brian P. Walcott, Christopher S. Ogilvy, Robert F. Spetzler, Michael T. Lawton*

*Corresponding author for this work

Research output: Contribution to journalArticle

78 Citations (Scopus)


BACKGROUND: The supplementary grading system for brain arteriovenous malformations (AVMs) was introduced in 2010 as a tool for improving preoperative risk prediction and selecting surgical patients. OBJECTIVE: To demonstrate in this multicenter validation study that supplemented Spetzler-Martin (SM-Supp) grades have greater predictive accuracy than Spetzler-Martin (SM) grades alone. METHODS: Data collected from 1009 AVM patients who underwent AVM resection were used to compare the predictive powers of SM and SM-Supp grades. Patients included the original 300 University of California, San Francisco patients plus those treated thereafter (n = 117) and an additional 592 patients from 3 other centers. RESULTS: In the combined cohort, the SM-Supp system performed better than SM system alone: area under the receiver-operating characteristics curve (AUROC) = 0.75 (95% confidence interval, 0.71-0.78) for SM-Supp and AUROC = 0.69 (95% confidence interval, 0.65-0.73) for SM (P <001). Stratified analysis fitting models within 3 different follow-up groupings (<6 months,±months>2 years, and .2 years) demonstrated that the SM-Supp system performed better than SM system for both medium (AUROC = 0.71 vs 0.62; P = .003) and long (AUROC = 0.69 vs 0.58; P = .001) follow-up. Patients with SMSupp grades ≤6 had acceptably low surgical risks (0%-24%), with a significant increase in risk for grades<.6 (39%-63%). CONCLUSION: This study validates the predictive accuracy of the SM-Supp system in a multicenter cohort. An SM-Supp grade of±is a cutoff or boundary for AVM operability. Supplemented grading is currently the best method of estimating neurological outcomes after AVM surgery, and we recommend it as a starting point in the evaluation of AVM operability.

Original languageEnglish
Pages (from-to)25-31
Number of pages9
Issue number1
Publication statusPublished - 2015


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