Marketers know that “new and improved” means people will pay attention. And in many cases, a product with this label is the best choice, one that will enrich our lives. But in medicine, doctors and patients sometimes need to be wary, because new is not always better.
Neurosurgery is a particularly fast-evolving field of medicine, and neurosurgeons are often faced with a variety of increasingly sophisticated techniques. They want to choose one that is effective in treating the patient’s problem, yet they don’t want to do any harm. This weighing of options and examining their possible consequences is known in medical language as looking at the “risk/benefit ratio”; the surgeon carefully studies the possible outcomes of doing a procedure as well as those of not doing one.
How do they decide what to do? And are there still situations when the time-worn plan of simply watching and waiting is the most appropriate choice?
Issues like this that arise in developing a patient treatment plan are considered very carefully by Dr. Sean D. Lavine, a neurosurgeon at Columbia University Irving Medical Center/NewYork-Presbyterian Hospital. At the American Heart Association International Stroke conference, he shared his expertise in the endovascular surgical treatment of brain and spinal cord arteriovenous malformations.
An arteriovenous malformation, or AVM for short, is the result of an abnormal connection between blood vessels. In order to look more closely at how a neurosurgeon might approach this condition, it’s worth talking a little bit about the brain’s blood vessels—the normal ones as well as the ones involved in an AVM.
Normally, blood vessels known as arteries bring oxygen and nutrients to all the tissues in the body including the brain. To deliver their cargo into the cells of those tissues, the arteries branch out into smaller and smaller blood vessels until they become tiny capillaries. These tiniest of blood vessels are in direct contact with cells, delivering oxygen and nutrients. In exchange, the cells release carbon dioxide and waste products which are carried away from the cells by other tiny blood vessels that branch out and become veins.
When blood arrives at any tissue through an artery it is under high pressure–that pressure is needed to push blood throughout the body. The branching into capillaries helps lower that pressure so that by the time the blood enters the veins it is under significantly less pressure.
With an AVM, a connection forms directly between arteries and veins, bypassing the capillaries in the area. Without the capillaries in place, there is nothing to slow down the flow of blood from the arteries. Arteries then deliver relatively high-pressure blood to the veins. This pressure can prove too much for the walls of the veins, leading to bleeding into the brain, or cerebral hemorrhage. This can subsequently lead to a stroke.
Also, since it’s the capillaries that deliver nutrients to the brain cells, without the presence of capillaries, an AVM may deprive the surrounding tissues of necessary nutrients. The larger the AVM, the bigger the blood flow problem. Also, if an AVM grows large enough it can compress nearby structures in the brain, causing further damage, or it may cause the patient to have seizures.
Due to the potentially serious complications caused by an AVM, neurosurgeons will closely monitor patients and develop a treatment plan tailored to each case. They will look at patient characteristics such as age and overall health and weigh the risks of doing any procedure versus the risks of treating without surgery.
The fact that there is a choice of treatments for AVMs is certainly good news. And according to Dr. Lavine, the great majority of patients improve after these procedures and have low rates of complications. Yet neurosurgeons want to be sure that the chance of a complication from any of these procedures is lower than the risk to the patient if nothing is done.
Dr. Lavine notes that at times performing the procedure is not worth the risk. In addition to the patient’s age, other medical issues, and general health, the surgeon will look at characteristics of the AVM itself. An AVM with any of the following traits may mean that watching and waiting is a better option than doing a procedure:
While any decision to perform a procedure is considered very carefully, specific AVM and patient features are evaluated on an individual basis. Thus, surgeons will look closely at these considerations and make their best decision with the patient.
We should feel fortunate that there have been so many advances in neurosurgery that physicians can now pick from a number of treatments for a potentially serious condition such as an AVM. It’s the neurosurgeon’s job to thoroughly evaluate and monitor the patient and weigh all factors prior to proceeding. As Dr. Lavine indicates, we strive to do what’s best rather than simply what’s possible.
Learn more about Dr. Lavine on his bio page here.
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