Clipping an intracranial aneurysm is among the most delicate of all operative procedures. One tiny slip and the artery bursts and a patient can die before the neurosurgeon can regain control and locate and stop the bleeding with a clamp. This is because the aneurysm is located deep inside the brain and the magnified surgical microscopic view must be abandoned because the operative field is suddenly filled with pulsatile blood flow everywhere. As the anesthesiologist my job is to immediately lower the patient's blood pressure using a rapidly acting vasodilator to a.) decrease blood loss to a minimum and b.) enable the neurosurgeon to better visualize the flooded operative field. Suction sometimes cannot clear the field enough to find the damaged blood vessel. I have watched this happen on several occasions from a vantage point 1-2 feet away on the other side of the surgical drapes in major teaching hospitals (UCLA and the University of Virginia).
The gold standard of neurosurgical care in these institutions translates as follows: 1. A senior neurosurgery resident ((in year 6 or 7 of their 7-year-long residency) preps and drapes the patient and after anesthesia induction, proceeds to locate and expose the aneurysm. This can take 2-4 hours under a high-powered surgical microscope.
2. The attending is contacted and told the aneurysm is ready for clipping. The attending may be anywhere, in or out of the building, doing anything. Sometimes they're in a nearby OR doing another case. I've waited as long as an hour for the attending to arrive, with the operative field covered with wet dressings and music playing to pass the time. That's some pretty expensive OR time BTW for which the patient will be billed.
3. The attending arrives, clips the aneurysm, and leaves. This can take anywhere from 15 minutes to several hours depending on the complexity of the case.
4. The neurosurgical resident closes the brain/dura/skull/scalp, taking anywhere from 2-4 hours.
My bona fides: https://scholar.google.com/citations?user=5DdrMc8AAAAJ&hl=en