Intraoperative aneurysm rupture refers to the tearing (bleeding) of a brain aneurysm during aneurysm surgery — that is, while the surgeon is operating on the aneurysm itself. It is one of the most feared and critical complications in neurosurgery.

Let me explain briefly:

An aneurysm is a balloon-like bulging and widening of a weak area in the wall of a brain blood vessel. The goal of surgical treatment is to isolate this balloon from the circulation — usually by placing a small metal clip on the neck of the aneurysm (clipping), or by filling its interior with coils via an endovascular approach.

Intraoperative rupture is the bursting of the aneurysm before this procedure is completed. It most often occurs during the following stages: while the tissues are being separated to reach the aneurysm (during dissection), during manipulation of the aneurysm neck while attempting to place the clip, and due to the tension created when the brain is retracted (retraction).

When it happens, the surgical field suddenly fills with blood, vision is lost, and the surgeon must act quickly. The principal techniques used in its management include temporary clipping (temporarily closing the feeding vessel to stop the bleeding), clearing the field with suction, and then placing the permanent clip. Coordination with the anesthesia team (for example, lowering the blood pressure) is also critical.

Its importance stems from this: intraoperative rupture can adversely affect the patient’s neurological outcome by increasing both the blood loss during surgery and the risk of ischemia due to the temporary interruption of blood flow to the brain.