Q What is Anal Fissure or Fissure-in-ano?
Anal Fissure is a tear in the anus causing a painful linear ulcer at the margin of the anus. It may cause itching, pain or bleeding. Fissures canextend upward into the lower rectal mucosa; or extend downward causing a swollen skin tag to develop at the anal verge, also known as a sentinel pile.
Q What are the causes of Anal Fissure?
Either extreme constipation or diarrhea, usually combined with nervous tension over a prolonged period of time, may produce anal abrasions, simple slit-like fissures, or acute ulcers at the anal verge. With constipation, this condition is usually caused by the passage of a hard dry stool that tears the anal lining upon defecation. With diarrhea, this condition is usually caused by an over use and over-wiping of an inflamed anal canal.
In some patients, the anal fissure doesn’t heal and becomes a painful sore that is constantly re-injured or torn with each bowel movement. The fissure usually develops a white fibrous base over time. Additionally, an external anal skin tag called a sentinel pile, and an enlarged papillae at the superior anal margin may develop.
Human body has a spontaneous reflex in which any pain in the sensitive lower part of anus causes reflex contraction (spasm) of the sphincter muscle. So the tear caused in the lower anal canal leads to sphincter muscle spasm .The resultant sphincter muscle spasm makes passage of even normal stools difficult and painful which further increases the spasm of sphincter muscle thereby starting a vicious cycle in which pain and sphincter muscle spasm increasing each other.
Q What are the symptoms of Anal Fissure?
Severe pain is the main symptom of acute anal fissure. Fissure produced pain at defecation may persists for hours. A small amount of bright red blood, which may or may not be mixed with stool, is common. A fissure produces pain disproportionate to its size . An inadequately treated fissure may lead to chronic fissure in which pain is relatively less and persists intermittently for weeks and months.
Q How is Fissure diagnosed?
Diagnosis can be made by inspection. Closer inspection will frequently reveal a tag or sentinel pile. After gentle separation of the skin of the anal verge, the ulcer usually posterior can be seen. Frequently the fibers of the internal anal sphincter muscle can be seen at the base of this punched-out ulcer. A well-lubricated finger with lidocaine ointment and a small caliber anoscope will help delineate the extent of the lesion. A colonoscope or sigmoidoscope exam might be useful to rule out abscesses, colitis, and other causes of rectal bleeding.
A fissure should be distinguished from an ulcer caused by Crohn’s disease, leukemia, or malignant tumors, because it is not shaggy, large or indolent. Fissures are seldom multiple. A biopsy can help to determine the diagnosis
Q How is Anal Fissure treated?
1) Medical treatment
At least 50 percent of fissures heal by themselves without the need for an operation. The longer that a fissure has persisted over time, the less likely it will be to heal by itself. Oftentimes, acute fissures heal by themselves spontaneously, with good anal hygiene consisting of a thorough cleansing after each bowel movement. The use of sitz baths (soaking the anal area in plain warm water for 20 minutes, several times a day) helps to relieve fissure symptoms, but may not actually aid in the healing process. A topical hydrocortisone preparation applied to the folds of the anal verge several times a day will help to relieve symptoms and aids the healing process.
A high fiber, well balanced diet, and encouragement of regular normal stools are important in helping to heal the fissure. If pain is severe, an anesthetic ointment can be introduced freely and frequently with the finger, utilizing finger cots.
Chemical sphincterotomy has been attempted using a wide range of agents, including nitric oxide and botulinum toxin. Since anal fissures are characterized by spasm of the internal anal sphincter and a reduction in mucosal blood flow, the aim of treatment is to relieve ischemia by reducing resting anal pressure and improving mucosal perfusion.
It has been shown that a local application of topical nitrates reduces anal sphincter pressure and improves anodermal blood flow. This dual effect results in fissure healing in more than 80% of patients. The principal side effect is headaches in 20%-100% of cases.
It has also been shown that a local injection of botulinum toxin near the fissure, causes denervation, sphincter muscle weakness, and reduction of resting anal sphincter pressure, which allows the fissure to heal. Fissure healing occurs in more than 60% of patients. The principal side effect is incontinence of flatus and or feces, which last for up to two months in 2% to 21% of cases.
2) Surgical Treatment
When surgical excision is required, the chronic fissure along with the sentinel pile, papilla, and adjacent crypts are dissected free from the underlying muscle. Associated internal and external hemorrhoids are removed. Usually the scar tissue in the posterior anal quadrant is completely denuded. The criteria for excision of fissures are chronicity and association with other anorectal disease such as hemorrhoids, mucosal prolapse, skin tags, enlarged papillae, anal contraction, and diseased crypts.
Sometimes, an anal dilation is performed to gently disrupt the scar tissue in the base of the fissure. Other times, cauterization by: laser, electrosurgical, or a chemical (i.e., silver nitrate) method; is used to simply denude or resurface the fissure base, to encourage the growth of new anal tissue.
Lateral partial internal sphincterotomy has been utilized for uncomplicated fissures. This surgery consists of a small operation to cut a portion of the anal muscle. This helps the fissure to heal by preventing pain and spasm, which interferes with healing. Cutting this muscle rarely interferes with the ability to control bowel movements.
At least 90% of patients who require surgery for this problem have no further trouble from fissures. More than 95% of patients achieve prolonged symptomatic improvement. About 5-percent of patients with fissures are “chronic fissure formers”, and for a variety of reasons (i.e., chronic constipation, failure to heal without scar tissue, etc.), will continue to develop new fissures despite all the efforts of medical and surgical treatment.