Transanal Hemorrhoidal Dearterialization (THD)
The medical condition known as hemorrhoids occurs when the veins lining the anal canal become swollen. As a result of this swelling, the connective tissue surrounding and supporting the veins can become lax, causing the swollen hemorrhoid to prolapse. Transanal hemorrhoidal dearterialization, or THD is a minimally invasive operation designed to treat both the swollen hemorrhoid and the excess connective tissue surrounding the hemorrhoid.
While the patient is sedated, an anoscope is inserted into the rectum and a Doppler ultrasound probe is inserted through the anoscope. The Doppler ultrasound helps the surgeon identify six areas of arterial blood flow, where the blood flows into the hemorrhoid. At the area of arterial flow, a suture is used to place an apical stitch, which occludes the artery and stops blood from flowing into the hemorrhoid. The same suture that is used to ligate the artery is then used to make a continuous stitch along the lax connective tissue. The end of the suture is tied back to the original apical stitch, lifting the excess hemorrhoidal tissue. This series of stitches is made at all six points of arterial flow.
One of the factors that make this procedure unique is that it cuts off blood flow into the hemorrhoid but leaves open the vein that takes blood away from the hemorrhoid. This combination helps to shrink the swollen hemorrhoid. Also, the procedure causes significantly less pain because it is performed entirely above the dentate line, where there are no pain nerves. This is a 20-minute operation that can be performed on an out-patient basis.