Cerebellar Arteriovenous Malformations: Anatomic Subtypes, Surgical Results, and Increased Predictive Accuracy of the Supplementary Grading System

Neurosurgery. 2012 Dec;71(6):1111-24. doi: 10.1227/NEU.0b013e318271c081.

Abstract

Background: Anatomic diversity among cerebellar arteriovenous malformations (AVMs) calls for a classification that is intuitive and surgically informative. Selection tools like the Spetzler-Martin grading system are designed to work best with cerebral AVMs but have shortcomings with cerebellar AVMs.

Objective: To define subtypes of cerebellar AVMs that clarify anatomy and surgical management, to determine results according to subtypes, and to compare predictive accuracies of the Spetzler-Martin and supplementary systems.

Methods: From a consecutive surgical series of 500 patients, 60 had cerebellar AVMs, 39 had brainstem AVMs and were excluded, and 401 had cerebral AVMs.

Results: Cerebellar AVM subtypes were as follows: 18 vermian, 13 suboccipital, 12 tentorial, 12 petrosal, and 5 tonsillar. Patients with tonsillar and tentorial AVMs fared best. Cerebellar AVMs presented with hemorrhage more than cerebral AVMs (P < .001). Cerebellar AVMs were more likely to drain deep (P = .04) and less likely to be eloquent (P < .001). The predictive accuracy of the supplementary grade was better than that of the Spetzler-Martin grade with cerebellar AVMs (areas under the receiver-operating characteristic curve, 0.74 and 0.59, respectively). The predictive accuracy of the supplementary system was consistent for cerebral and cerebellar AVMs, whereas that of the Spetzler-Martin system was greater with cerebral AVMs.

Conclusion: Patients with cerebellar AVMs present with hemorrhage more often than patients with cerebral AVMs, justifying an aggressive treatment posture. The supplementary system is better than the Spetzler-Martin system at predicting outcomes after cerebellar AVM resection. Key components of the Spetzler-Martin system such as venous drainage and eloquence are distorted by cerebellar anatomy in ways that components of the supplementary system are not.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Arteriovenous Malformations* / classification
  • Arteriovenous Malformations* / pathology
  • Arteriovenous Malformations* / surgery
  • Cerebellum / pathology*
  • Cerebellum / surgery*
  • Cerebral Angiography / methods*
  • Chi-Square Distribution
  • Child
  • Embolization, Therapeutic
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Postoperative Complications
  • Predictive Value of Tests
  • ROC Curve
  • Retrospective Studies
  • Treatment Outcome
  • Young Adult