Residual AVMs

Introduction

The primary goal in the management of intracranial arteriovenous malformations (iAVMs) is the total obliteration or resection of the AVM nidus. This is the only way to eliminate the risk of future hemorrhage. The cure rate for iAVMs treated with microsurgical resection ranges from 70% to more than 90%, depending on the characteristics of the lesion. With radiosurgery, cure rates range from 60% to 80%, and a long period of observation is required until obliteration occurs. AVM cure with embolization alone is rare, but possible in select cases.

Given the complexity of this disease entity and the various treatment options available, posttreatment residual can occur. The incidence of residual iAVMs varies based on the Spetzler-Martin grade of the lesion and the initial treatment that is utilized. For example, resection of an iAVM with a low Spetzler-Martin grade is unlikely to result in a residual nidus, whereas staged embolization as the sole treatment of a high-grade iAVM will almost certainly leave the patient with residual nidus. Thus the proper initial management of iAVMs is of the utmost importance. The management of residual iAVMs is challenging, and as in initial iAVM treatment, there are multiple modalities available to clinicians, including observation, stereotactic radiosurgery (SRS), microsurgical resection, or embolization, which can be done alone or in combination with radiosurgery or open surgery. The decision-making involved in selecting subsequent treatments is complex and can vary based on the initial treatment modality used, the patient’s clinical status, and the anatomical characteristics of the patient’s AVM. To better understand how to treat residual iAVMs, clinicians must first appreciate how residuals occur and how best to avoid them.

Types of Residual