Lateral internal sphincterotomy is an

operation Operation or Operations may refer to: Arts, entertainment and media * ''Operation'' (game), a battery-operated board game that challenges dexterity * Operation (music), a term used in musical set theory * ''Operations'' (magazine), Multi-Ma ...

performed on the

internal anal sphincter The internal anal sphincter, IAS, (or sphincter ani internus) is a ring of smooth muscle that surrounds about 2.5–4.0 cm of the anal canal; its inferior border is in contact with, but quite separate from, the external anal sphincter. It is ...

muscle for the treatment of chronic

anal fissure An anal fissure is a break or tear in the skin of the anal canal. Anal fissures may be noticed by bright red anal bleeding on toilet paper and undergarments, or sometimes in the toilet. If acute they are painful after defecation, but with chronic ...

. The internal anal sphincter is one of two muscles that comprise the anal

sphincter A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning. Sphincters are found in many animals. There are over 60 types in the hum ...

which controls the passage of

feces Feces ( or faeces), known colloquially and in slang as poo and poop, are the solid or semi-solid remains of food that was not digested in the small intestine, and has been broken down by bacteria in the large intestine. Feces contain a relati ...

. The procedure helps by lowering the resting pressure of the internal anal sphincter, which improves blood supply to the fissure and allows faster healing. The procedure has been shown to be very effective, with 96% of fissures healing at a median of 3 weeks in one trial.

Indications

Lateral internal sphincterotomy is the preferred method of surgery for persons with chronic anal fissures, and is generally used when medical therapy has failed. It is associated with a lower rate of side effects than older techniques such as posterior internal sphincterotomy and anoplasty, and has also been shown to be superior to topical

glyceryl trinitrate Nitroglycerin (NG), (alternative spelling of nitroglycerine) also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive liquid most commonly produced by nitrating ...

(GTN 0.2% ointment) in long term healing of fissures, with no difference in fecal continence.

Surgical technique

Lateral internal sphincterotomy is a minor operation which can be carried out under either

local Local may refer to: Geography and transportation * Local (train), a train serving local traffic demand * Local, Missouri, a community in the United States * Local government, a form of public administration, usually the lowest tier of administrat ...

general anaesthesia General anaesthesia (UK) or general anesthesia (US) is a medically induced loss of consciousness that renders the patient unarousable even with painful stimuli. This effect is achieved by administering either intravenous or inhalational general ...

; a report in 1981 showed that general anaesthesia is preferable due to high rates of fissure recurrence in patients treated under local anaesthesia. This operation is generally carried out as a day case procedure. It can be performed with either "open" or "closed" techniques: * the open technique involves making an incision across the intersphincteric groove, separating the internal sphincter from the anal mucosa by blunt dissection, and dividing the internal sphincter using scissors. * the closed technique or subcutaneous technique involves making a small incision at the intersphincteric groove, inserting a

scalpel A scalpel, lancet, or bistoury is a small and extremely sharp bladed instrument used for surgery, anatomical dissection, podiatry and various arts and crafts (either called a hobby knife or an X-acto knife.). Scalpels may be single-use disposa ...

with the blade parallel to the internal sphincter and advancing it along the intersphincteric groove, and then rotating the scalpel towards the internal sphincter and dividing it. In both techniques the lower one third to one half of the internal sphincter is divided, to lower the resting pressure without destroying the effect of the sphincter. The closed technique results in a smaller wound, but both techniques appear to be similarly effective.

Complications

* Minor

fecal incontinence Fecal incontinence (FI), or in some forms encopresis, is a lack of control over defecation, leading to involuntary loss of bowel contents, both liquid stool elements and mucus, or solid feces. When this loss includes flatus (gas), it is referred ...

and difficulty controlling flatulence are common side effects following surgery. Persistent minor fecal incontinence has been reported in 1.2% to 35% of patients; however, this does not appear to be significantly different to the rate of minor fecal incontinence experienced by patients treated with topical GTN. *

Hemorrhage Bleeding, hemorrhage, haemorrhage or blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vag ...

can occur, more often with the open technique, and may require suture ligation. *

Perianal abscess Anorectal abscess (also known as an anal/rectal abscess, or perianal/perirectal abscess) is an abscess adjacent to the anus. Most cases of perianal abscesses are sporadic, though there are certain situations which elevate the risk for developin ...

occurs in about 1% of closed sphincterotomies, generally in association with

anal fistula Anal fistula is a chronic abnormal communication between the epithelialised surface of the anal canal and usually the perianal skin. An anal fistula can be described as a narrow tunnel with its internal opening in the anal canal and its externa ...

caused by a breach of the anal mucosa by the scalpel.

Incision and drainage Incision and drainage (I&D), also known as clinical lancing, are minor surgical procedures to release pus or pressure built up under the skin, such as from an abscess, boil, or infected paranasal sinus. It is performed by treating the area with an ...

of the abscess and

fistulotomy A fistulotomy is the surgical opening of a fistulous tract. They can be performed by excision of the tract and surrounding tissue, simple division of the tract, or gradual division and assisted drainage of the tract in a ''seton''; a cord passed th ...

are required.

References

{{Operations and other procedures on the digestive system Digestive system surgery

Indications

Surgical technique

Complications

See also

References