Introduction: The most feared event during AVM surgery is AVM intraoperative rupture. The bleeding is torrential, more difficult to control than an aneurysm rupture, and significantly impacts the rest of the resection. Our objective is to analyze factors leading to such event and the tenets to avoid it and successfully deal with it.
Methods: During a 15 year period 600 brain AVMs were microsurgically treated by the senior author and prospectively collected in the cerebrovascular service database. 32 patients (5.3%) had an intraoperative rupture. AVM characteristics, operative strategy and outcomes were analyzed in these patients. Causes of AVM rupture were categorized into: 1) rupture of feeding arteries; 2) premature venous occlusion; and 3) nidal penetration.
Results: Out of 32 patients with an intraoperative rupture, 14 (44%) were Spetzler-Martin grade III and 23 (72%) had a supratentorial AVM. Most intraoperative bleeding events were due to the presence of small, friable, uncoagulable vessels (12 patients, 38%); nidal penetration (7 patients, 22%) or premature occlusion of the draining vein (5 patients, 16%). Age and AVM location were not related with the likelihood of an intraprocedural bleed. Two patients died from complications directly related with the intraoperative event. Sixteen out of the 32 intraoperative ruptures (50%) happened during the first 5 years of the senior author’s experience.
Conclusions: Uncontrolled bleeding from a brain AVM is the one thing above all others that unnerves surgeons in the operating room and tests their skills. Intraoperative bleeds are associated with intrinsic AVM characteristics (small friable uncoagulable vessels) but also with technical mistakes like underestimated nidus border or unintentional occlusion of venous drainage . Surgeon’s experience translates into a lower likelihood of intraoperative rupture of the AVM. The learning curve in AVM surgery diminishes errors in judgment and technique closely related to the intraoperative rupture.
Patient Care: This research project intends to improve patient care by:
1) Identifying brain AVM patients that may have a higher risk of intraoperative rupture
2) Better assess patient’s outcome after such complication
3)Helping the surgeon to recognize and address the technical mistakes that can lead to an intraoperative rupture
Learning Objectives: By the conclusion of this session, participants should be able to:
1)Describe the causes of brain arteriovenous malformations rupture
2)Describe the microsurgical techniques to deal with this complication
3)Understand the impact of an intraoperative bleed in patient’s outcome
4)Identify the role of surgeon’s experience in the related judgment and technical errors