Transanal Dearterialization of Hemorrhoid (THD)

Overview of THD hemorrhoid procedure

Recent medical advancements in hemorrhoid surgery had resulted in a patient-friendly alternative treatment procedure called the THD Doppler surgery. THD is the short form of Transanal Hemorrhoidal dearterialization. This procedure has proven to be very effective in treating hemorrhoids without modifying the anal anatomy. It involves ligation of the arteries; dearterialization. Ligation of hemorrhoidal arteries and folding the rectal submucosa reduces blood overflow to the affected tissue. The reduced blood flow will help your surgeon to visually find the right position of the displaced prolapsed hemorrhoid tissues. Your surgeon can now put back the tissues into its original site in the anal track without removal of any tissues. THD procedure intervenes in the pathophysiological processes of hemorrhoidal disease. THD surgical method can be used to treat all grades of hemorrhoids.

THD procedure

Usually, the THD procedure is performed on a patient only after a complete analysis of the hemorrhoidal history of the patient. This analysis helps the doctor in determining whether arterial hemorrhoidal ligation is enough or should be followed by the dearterialization of mucopexy for treating the hemorrhoids in the patient. To assess spontaneous bleeding, hemorrhoidal engorgement, and prolapse of pile tissue and rectal mucosa both anorectal examination and anoscopy are performed while the patient rests and strains. THD procedure is normally performed in patients with active hemorrhoidal even after changes in diet/lifestyle, medications and minor procedures like rubber band ligation or sclerotherapy have not proven effective. The patient is administrated with general anesthesia or local anesthesia before the onset of surgery. The patient is also given one or two enemas as the surgery is performed in the anal canal. The surgeon may position the patient in either the lithotomy position or the prone position depending on his preference. The former position allows realistic locating of rectal mucosa and prolapsed hemorrhoids. THD is commonly performed using a specific device produced in Italy. This device consists of a proctoscope mantled with a light source and a Doppler probe. The double crystal in the Doppler probe helps in the better focusing of the ultrasound waves. This in turn helps in easy identification of large-diameter arteries positioned in the upper layers of the rectal wall. Both are crystals are placed apart with sufficient space in between them which allows the adequate vibration of the crystals. The hemorrhoidal artery located using the Doppler probe mounted on oblique support should lie within the operative window so that it can be ligated selectively. First, the anal area is completely lubricated. Then, the lower rectum is reached by inserting a proctoscope through the anal canal. The operation is started by the surgeon at any point about 5 – 6 cm from the anal verge. The Doppler system is turned on. The surgeon rotates or tilts the proctoscope to identify the Doppler signal corresponding to the 6 branches of the hemorrhoidal arteries that are positioned at 1, 3, 5, 7, 9, and 11 o’clock of the anal rectal circumference. Doppler signal also helps in the accurate identification of the arteries positioned at unusual positions. Then the proctoscope is moved back slowly to follow the hemorrhoid artery leading up to its apex to locate the best Doppler signal. The signal is usually clear at the hemorrhoidal site. Anatomical and acoustic findings have confirmed that the prime place to located the hemorrhoidal arteries will be the distal part of the anal rectum. This is the principle of Doppler-guided dearterialization. Once, the best place is located, the Doppler set up is turned off. When the artery is identified in a patient requiring dearterialization alone, the artery is ligated immediately at the point of best Doppler signal with a ‘Z-stitch’. When a patient has to undergo mucopexy as well, the mucosa is marked with a marker point (electro-cautery) at the location of the best Doppler signal. Once the hemorrhoidal artery is marked, the proctoscope is pushed into the rectum, and as a ‘fixation point’ of the mucopexy, a ‘z-stitch’ is sutured. The length of the submucosa and prolapsing mucosa determines the proximal end of the mucopexy. Then, the artery is ligated. The sliding part of the proctoscope is moved back to expose the rectal mucosa. Then, the mucopexy is performed. A continuous suture is used in the mucopexy along the longitudinal axis in a proximal-to-distal direction. The sutures are sutured with an optimal distance of 0.5 cm between them. This helps too tight sutures or too loose sutures. The surgeon makes sure to put two sutures above and below the marker point to trap the hemorrhoidal artery. So, the artery is entrapped within the sutures and the dearterialization is performed using the Doppler-guided dearterialization principle. To ensure blood flow from hemorrhoids, the vertical rows should be spaced from each other. At the apex of the hemorrhoid, the mucopexy running suture is stopped to avoid it being included in the mucopexy. Lastly, the running suture is softly tied. This method is called a hemorrhoid-sparing procedure due to its effectiveness.

Post-operative complications

This procedure has very little after complications. If the sutures are tight it may lead to tissue ischemia or if too loose causes the early rupture of the suture leading to the collapse of the hemorrhoidal artery. The risk of thrombosis is increased due to the circumferential obliteration of the anal tissue. Urinary retention and Tenesmus are other post-operative complications of the THD procedure. Tenesmus is the condition in which the patient feels the urge to defecate even without the presence of feces. Doctors usually prescribe medications to reduce the pain.

Advantages of THD procedure

  • This is suitable for patients with hemorrhoids who are immune to conservative hemorrhoid treatments.
  • This is a minimally invasive procedure that reduces the pain (during and post-operative) which is the main complication in the conservative methods.
  • The hemorrhoidal reoccurrence rate is very low.
  • It has a shorter recovery time and the patient returns to normal condition in 2-3 days.
  • THD is repeatable and is the most effective procedure for the treatment of prolapsed and thrombosed hemorrhoids.
  Additional Resources: 
  1. THD Doppler Brief Overview
  2. Treating haemorrhoids (piles) by tying off their blood supply
  3. THD technique paper

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