What is an anal fissure?
Anal fissures are a break or tear in the skin of the anal canal, usually seen as a linear ulcer at the anal verge. Anal fissures are most commonly located posteriorly in the midline [6 o clock position], but may be sometimes anteriorly at 12 o clock position. Lateral fissures are also seen sometimes and may be associated with underlying intestinal diseases like tuberculosis or inflammatory bowel disease. Acute fissure may be a superficial erosion of the anal mucosa. Chronic fissures are deep down to the internal anal sphincter muscle and usually accompanied with hypertrophied anal papillae and a sentinel tag. The internal sphincter muscle of anal canal is usually in spasm and thus the fissures are painful.
They occur equally frequently in men and women and most often occur in young adults.
Symptoms of anal fissure
Acute fissures cause pain during and after defecation [painful or difficult evacuation]. Anal fissures may also cause bright red anal bleeding on the toilet. Blood may be seen alongside of the stools while defecation. In chronic fissures pain is less intense. Chronic fissures may cause mucous discharge, soiling of the undergarment and pruritis in the anal region.
Most anal fissures are caused by overstretching of the anal mucosa beyond its capacity. In adults, fissures may be caused by constipation, passing of large, hard stools, by prolonged diarrhea or due to anal sex. In older adults, anal fissures may be caused by decreased blood flow to the area.
It has been seen that fissures are associated with increased resting anal pressure due to spasm of internal sphincter muscle of anal canal. The most common reason for development of fissure is spasm of the internal sphincter muscle of anal canal. Sphincter spasm results in impaired blood supply to the anal mucosa. The result is a non-healing ulcer, which may become infected by fecal bacteria. Resting pressures of anal canal in patients with fissures are twice as high as normal subjects. Restoration of anal canal pressure by lateral sphincterotomy is associated with improvement of symptoms and healing of fissures in 98% of patients.
Other causes of anal fissures include:
§ Poor toileting in young children.
§ Childbirth trauma in women.
§ Inflammatory bowel disease [crohn’s disease or ulcerative colitis], tuberculosis, gonorrhea, syphilis, herpes and AIDS.
§ Fissures may be associated with leukemia, underlying cancer of anal canal/ rectum etc.
§ Anal sex.
§ High fiber diet.
§ Avoiding constipation and straining when defecating.
§ Prompt treatment of diarrhea may reduce anal strain.
§ Maintaining cleanliness and good anal hygiene. Using soft toilet paper or cleaning with water.
§ Frequent diaper changes and keeping the area dry can prevent anal fissure in newborn and children.
§ Avoid coffee, alcoholic beverages, smoking and spicy food.
Superficial anal fissures will often heal within a few weeks on conservative management. However anal fissures which are deep and become chronic will not heal spontaneously, and may require medications or surgery.
Medical management of fissure
General measures like warm sitz bath, topical anesthetic agents, stool softeners and high fiber diet are usually advised.
Non-surgical treatments to reduce resting anal pressure may be tried initially. These include topical ointments [nitroglycerine or nifedepine or diltiazem]. Local application of these ointments will relax the sphincter muscle and thus allow the fissure to heal. A common side effect and drawback of nitroglycerine and other ointments is headache, which limits patient acceptability. Topical ointments used for relaxation of anal sphincter may result in healing of acute fissures in 50 - 75% of patients but carries a high recurrence rates.
Injection of botulinum toxin (Botox) into the anal sphincter to relax it is another treatment for anal fissures, used by colorectal surgeons. However, in many cases of Botox injections the patients eventually had to undergo surgery as the injection failed to cure the fissure. The success rate for botox injection is 75% at the end of one year and drops to 55% on long term follow up. Side effects of botox include urinary retention, heart block, muscle weakness, postural hypotension and allergic skin reactions.
Various surgical options used for treatment of anal fissures are:
 Anal stretch
 Lateral sphincterotomy [open or closed]
 Anoplasty [V-Y Advancement flap]
Anal sphincter stretch is done to disrupt the sphincter fibers and reduce the resting anal pressure. It is associated with anal incontinence in a small proportion of cases and has been given up by most of the surgeons. Anal stretch should be avoided in women and elderly patients because of increased likelihood of incontinence.
Lateral sphincterotomy is presently the Gold Standard treatment for curing anal fissures associated with high resting anal pressures, chronic anal fissures and fissures associated with underlying fistula. In this procedure the internal anal sphincter muscle is partially divided in order to reduce spasm. This results in decrease in resting anal pressure and improvement of the blood supply. The sentinel pile and hypertrophied anal papillae are also excised. Lateral sphincterotomy is considered as a superior method of treating anal fissures because it has a higher rate of fissure healing [98%], fewer side effects and better long term symptomatic improvement.
Anoplasty [V-Y Advancement flap] is used for treatment of fissures associated with anal stenosis and fissures with normal resting anal pressure.
These operations may be done as day care surgery under local or general anesthesia.