Introduction: Spetzler-Martin Grade III arteriovenous malformations (AVMs) represent a heterogeneous group of lesions. In this study we evaluate predictors of outcomes following microsurgery of Grade III lesions and assess a revision of the grading scale.
Methods: From a consecutive series of 264 patients with cerebral arteriovenous malformations treated with microsurgery, 81 were Spetzler-Martin Grade III. We conducted a retrospective review of patient and AVM characteristics. Univariate predictors of outcome (p<0.15) were included in multivariate analysis.
Results: Sixty-three patients (77.8%) had small AVMs (S1V1E1), 15 (18.5%) were medium and eloquent (S2V0E1), 3 (3.7%) were medium and deep (S2V1E0), and none were large (S3V0E0). Complete microsurgical resection was accomplished in all patients. Permanent surgical complications occurred in 8 patients (9.9%), including death in 4 (4.9%). Permanent surgical complications occurred in 2 of 63 patients (3.2%) with small AVMs, 5 of 15 (33.3%) with medium/eloquent AVMs, and 1 of 3 (33%) with medium/deep AVMs. Patients with medium Grade III AVMs were significantly more likely to have complications than small Grade III AVMs (OR=15.3l; 95% CI 2.74-84.81, p=0.002). Additional univariate predictors of new deficits or death following microsurgery included size (OR=15.3; 95% CI 2.74-84.81, p=0.002), deep venous drainage (OR=10.50; 95% CI 2.16-51.02, p=0.004), and hyperlipidemia (OR=5.00; 95% CI3.03-33.33). In multivariate analysis the only factor predictive of outcome was medium and eloquent and medium/deep AVM.
Conclusions: Grade III AVMs are a diverse group of lesions that are associated with a varied risk profile following microsurgery. Small Grade III lesions are associated with a similar risk profile as Grade I and II lesions. Medium Grade III lesions are associated with greater risk following surgical therapy and conservative or multimodality therapy may be the best therapeutic option.
Patient Care: Improve patient selection for treatment of AVMs
Identify predictors out outcome following treatment
Refine grading of Spetzler Martin Grade III AVMs
Learning Objectives: 1.Assess morbidity and mortality following surgery for Spetzler Martin Grade III AVMs
2.Determine predictors of outcome in Spetzler Martin Grade III AVMs
3.Revise the grading scale and risk of treatment for select grade III lesions