A proposed grading system for arteriovenous malformations

TLDR

Estimating surgical risk is essential for treating patients with arteriovenous malformations. The authors propose a simple, broadly applicable grading system to predict morbidity and mortality associated with operative treatment of AVMs. The grading system classifies AVMs into six grades based on size, venous drainage pattern, and eloquence of adjacent brain, ranging from small superficial lesions in non‑eloquent cortex (Grade I) to large deep lesions in critical areas (Grade V) and essentially inoperable lesions (Grade VI). Retrospective analysis shows the grading scheme correlates with postoperative neurological complications, enabling comparison across series and aiding management decisions.

Abstract

✓ An important factor in making a recommendation for treatment of a patient with arteriovenous malformation (AVM) is to estimate the risk of surgery for that patient. A simple, broadly applicable grading system that is designed to predict the risk of morbidity and mortality attending the operative treatment of specific AVM's is proposed. The lesion is graded on the basis of size, pattern of venous drainage, and neurological eloquence of adjacent brain. All AVM's fall into one of six grades. Grade I malformations are small, superficial, and located in non-eloquent cortex; Grade V lesions are large, deep, and situated in neurologically critical areas; and Grade VI lesions are essentially inoperable AVM's. Retrospective application of this grading scheme to a series of surgically excised AVM's has demonstrated its correlation with the incidence of postoperative neurological complications. The application of a standardized grading scheme will enable a comparison of results between various clinical series and between different treatment techniques, and will assist in the process of management decision-making.