Wednesday, July 18, 2007

Neurological Surgery

Kidney Transplant

This past week, I had the chance to observe several more procedures in the OR, including observing a kidney transplant surgery with Dickson. I watched the removal of the kidney from one patient, handling of the kidney while the recipient was opened up, and attachment of the kidney into the recipient. The connections that must be attached when put in the recipient are shown in the figure. I found the handling of the kidney external to the human body to be especially interesting. Since there were delays in opening up the recipient, the transplant doctor kept the kidney in slush. Then, when the recipient was ready to receive the kidney, the doctor wrapped the kidney in some wet cloths packed with slush in what he described as a ‘sushi roll’. He used this as an ice pack to keep the kidney cold while attaching the kidney to the patient and mentioned the need for a better kidney preservation machine that could mimic the human body and would not require cooling the kidney down.

www.surgeryencyclopedia.com

Neurological Surgery Aneurysm Treatment

As I’ve mentioned previously, there are two major techniques to treat brain aneurysms – clipping the aneurysm or using filling the aneurysm with coils through endovascular means, also known as coil embolization. Coil embolization is much more attractive because it is less invasive, however there are limitations on when coil embolization can be used, depending on aneurysm shape, as well as problems with aneurysm recurrence (defined as aneurysm neck enlargement or recanalization) when the aneurysm is not adequately occluded.

Computer illustration of process of clipping an aneurysm. www.thejns-net.org

Figure illustrates filling of aneurysm with coil. www.brainaneurysm.com

Traditionally, coils have been made out of platinum. One popular coil is the gugliemi detachable coil (GDC) which has a shape memory effect. It is routed into the aneurysm and detached from a pusher wire using a low current. Due to the problems demonstrated with significant recurrence rates, researchers have been trying to come up with techniques to increase the percent occlusion (defined as the volume of the coil over the volume of the aneurysm). A modification of the GDC coil was introduced, called the Matrix coil, which has an absorbable polyglycolic-polylactic acid (PLGA) copolymer coating on platinum coils. The PLGA is absorbed by the body within 90 days. The premise for why this technology is an improvement over GDC is that it provides a much higher initial occlusion. I am working on analyzing clinical data to investigate and compare the outcomes of the different treatments.

Figure illustrates mechanism for inserting matrix coils as well as different configurations of coils. www.bostonscientific.co.uk

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