In the June issue of Journal of Neurosurgery Pandey et al present their retrospective series of 100 patients with treated Spetzler-Martin Grade III AVMs (1). The patients were treated between 1984 and 2010. The authors subdived the Grade III AVMs into four group according to size, eloquence, and presence of deep venous drainage. Most of the patients were treated with endovascular embolization combined with microsurgery (41%), and endovascular embolization combined with radio surgery (25%). The complete obliteration rate was 87.6%. The overall mortality was 1% and 14% had new neurological deficits. The authors end up recommending the division of Grade III AVMs into two groups: small (<3cm) and large (>3cm) since this reflects well with the risks related to the treatment of these lesions.

This is a carefully conducted study. During the study period the endovascular treatment of these lesions has taken giant leaps and many of the patients are now cured with very low morbidity. The Spetzler-Martin grading is originally surgical but with new modifications can be used in the risk evaluation for multi-modal treatment.