Tag Archives: LIS

What is Sphincterotomy?

Sphincterotomy is a surgical procedure to cut or stretch sphincter. Sphincter is the circular muscles around the anus that control bowel movement (BM).

Sphincterotomy is a treatment for patients that suffers from anal fissures, piles or sometimes described as passing of glass. The purpose of sphincterotomy is to loosen the sphincter muscles and facilitate healing.



The procedure or operation is not to be confused with fistulotomy. Fistulotomy is a surgical operation on fistula, an abnormal growth in various tracts in the body organ. However, it is common to have both sphincterotomy and fistulotomy performed in the same operation.

There are 2 types of sphincterotomy :

  1. Lateral Internal Sphincterotomy (LIS) – This the only type of sphincterotomy used to treat anal fissure.
  2. Endoscopy Sphincterotomy (EST) – This is a type of surgery using endoscope to remove gallstones from bile (not a treatment for anal fissure)

Sphincterotomy is not the only treatment available for anal fissures. Below are some other common treatments, usually for less serious cases of anal fissure :

  • High fibre diet
  • Stool softneners
  • Botox

Botox (botulinum toxin) treatment is also known as chemical sphincterotomy. It is performed by injecting Botox into the internal sphincter. It involves no surgical procedure.

In many anal fissure cases, sphincterotomy usually is the final solution suggested when all other treatments failed.

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Lateral Internal Sphincterotomy

Lateral internal sphincterotomy (LIS) is the name for the surgical operation to make a cut on the sphincter muscle of the anus. LIS is a treatment for anal fissure. More accurately, the main purpose is to help the fissure to heal by itself, by relaxing the sphincter muscle through sphincterotomy.

“Lateral” is the surgical approach to start the incision entry. For some types of surgery, all lateral, posterior and anterior approaches can be used. For sphincterotomy, however, lateral approach is the only method used.

“Internal” refers to the internal sphincter, where the incision is targeted. The cut is often made to the superficial sphincter as this reduces the chance of side effects later.



Despite its rather complex-sounding name, lateral internal sphincterotomy is really a simple surgery to make one small cut to the anal muscle. It generally takes about 20 to 30 minutes to perform. And patients are admitted and discharged on the same day.

Lateral internal sphincterotomy operation itself does not remove skin tag. Anal skin tag can be removed by either ligation or cauterizing. Nevertheless, it is not uncommon to have both sphincterotomy and skin tag removal performed in the same operation.

Other related operation that might be performed with sphinterotomy (depending on the anal fissure conditions) are :

  • hemorrhoidectomy
  • fissurectomy
  • fistulotomy

Again, these operations can be performed together during lateral internal sphincterotomy. You should check with your surgeon the exact name of the operation to be performed. It is a good idea to confirm this with your nurse too, as they are the ones usually checking you into the operation theatre.

Overall, lateral internal sphincterotomy is not a risky procedure and complication rarely happens. Similarly, probability of side effects appears to be low, although there are no official statistics on patients sampling. With the right post-operation care, most patients can expect a full recovery and a normal life again.

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