Type of Surgery
Last updated: 11/24/2009
The exact timing for surgical treatment of cerebral aneurysms is historically a controversial subject in neurosurgery and is dependent on many factors including patient age, aneurysm size, aneurysm location, density of SAH, and whether the patient...
is comatose. Research indicates that early treatment, within the first 48 hours after hemorrhage, is generally associated with better outcomes, particularly because of the reduction of two serious complications of rupture: re-bleeding and vasospasm.
Re-bleeding is the most important cause of death if a patient survives the initial bleed and will happen in approximately 50% of all patients with a ruptured aneurysm who do not undergo surgical treatment. The peak occurrence of re-bleeding is within the first few days after rupture. About 60% of patients who re-bleed die.
The second major cause of death after rupture is vasospasm, a condition where the arteries at the base of the brain become irritated and constrict so tightly that blood cannot flow to critical brain regions. This spasm may result in further brain damage or induce re-bleeding, and much of the medical treatment after the aneurysm ruptures and prior to surgical treatment is designed to prevent this complication.
The procedure itself begins with general anesthesia of the patient and shaving of the area of the skull where the craniotomy, or opening of the skull bone, will occur. The exact position of the opening depends on the approach that the neurosurgeon will use to reach the aneurysm. The approach varies with the exact location of the aneurysm within the brain's cardiovascular system.
Once the bone flap is removed, the various layers of tissue are cut away to expose the brain. Blocking brain tissue is gently retracted back to expose the area containing the abnormal vessel formation. Surgical techniques performed through a microscope are then utilized to dissect the aneurysm away from the feeding vessels and expose the neck to receive the clip. Clips are manufactured in various types, sizes, shapes, and lengths to accommodate the needs for the various positions, shapes, and sizes of aneurysms. Clips are made of different kinds of materials, with titanium being popular because the material will not interfere with later magnetic resonance imaging (MRI) testing.
The clip is placed on the neck of the aneurysm in order to isolate it from the normal circulation. Careful clip placement will stop the flow of blood into the aneurysm, causing it to deflate or obliterate. Proper placement causes aneurysm obliteration and avoids damage to the adjacent vessels or their branches. Once the clip is in place, the brain tissue is carefully lowered back into place, the various layers sutured closed, and the bone flap is reseated for healing. The skin and other outer layers are also sutured closed. Bandages protect the area during healing.
An artist's representation of what nerves and nerve bundles look like at the microscopic level. It also shows how the anatomy of a nerve allows it to transmit electrical signals and communicate with other neurons (nerves).
Cerebral aneurysm repair involves corrective treatment of an abnormal blood-filled sac formed by localized expansion of an artery or vein within the brain. These sacs tend to form at the juncture between a primary vessel and a branch. If the vessel involved is an artery, the lesion is also known as a berry aneurysm because of its round, berry-like appearance.
The purpose of the surgical treatment of cerebral aneurysms is to isolate the weakened vessel area from the blood supply. This is commonly done through the strategic placement of small, surgical clips to the neck of the lesion. Thus, the aneurysm becomes isolated from the normal circulation without damaging adjacent vessels or their branches and shrinks in size to become undetectable, a process known as aneurysm obliteration.
Select comparative data from 1999 to 2006 include a decrease of 14 percent in the number of neurosurgeons in private practice and a decrease of 13 percent in the number of neurosurgeons in solo practice.
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