Lateral internal sphincterotomy is an operation

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

 performed on the internal anal sphincter muscle for the treatment of chronic anal fissure

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 the toilet paper, sometimes in the toilet. If acute they may cause severe periodic pain after defecation but with chronic fissures pain intensity is often less...

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

Sphincter

A sphincter is an anatomical structure, or a circular muscle, that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning...

 which controls the passage of feces

Feces

Feces, faeces, or fæces is a waste product from an animal's digestive tract expelled through the anus or cloaca during defecation.-Etymology:...

. 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 (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 anesthetic

A local anesthetic is a drug that causes reversible local anesthesia, generally for the aim of having local analgesic effect, that is, inducing absence of pain sensation, although other local senses are often affected as well...

 or general anaesthesia

General anaesthesia

General anaesthesia is a state of unconsciousness and loss of protective reflexes resulting from the administration of one or more general anaesthetic agents...

; 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
  Scalpel
  A scalpel, or lancet, is a small and extremely sharp bladed instrument used for surgery, anatomical dissection, and various arts and crafts . Scalpels may be single-use disposable or re-usable. Re-usable scalpels can have attached, resharpenable blades or, more commonly, non-attached, replaceable...
  
   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
  Fecal incontinence is the loss of regular control of the bowels. Involuntary excretion and leaking are common occurrences for those affected. Subjects relating to defecation are often socially unacceptable, thus those affected may be beset by feelings of shame and humiliation...
  
   and difficulty controlling flatulence are common side effects following surgery. Persistent minor fecal incontinence has been reported in 1.2% to 3.5% 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
  Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
  
   can occur, more often with the open technique, and may require suture ligation.
• Perianal abscess
  Perianal abscess
  Anorectal abscess is an abscess adjacent to the anus. It arises from an infection at one of the anal crypts of Morgagni which leads to inflammation and abscess formation...
  
   occurs in about 1% of closed sphincterotomies, generally in association with anal fistula
  Anal fistula
  Anal fistula, or fistula-in-ano, is an abnormal connection between the epithelialised surface of the anal canal and the perianal skin....
  
   caused by a breach of the anal mucosa by the scalpel. Incision and drainage
  Incision and drainage
  Incision and drainage and 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...
  
   of the abscess and fistulotomy
  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 by means of a seton; a cord passed through the tract in a loop which is slowly...
  
  are required.

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