Anal fissure definition

What is an anal fissure?

An anal fissure is linear or oval ulcer in the anal canal. It usually extends from the linea dentata to the verge of the anal orfice. This small crack in the epithelial surface may cause severe pain after bowel movements. Small amounts of bright red blood could be present and that is why anal fissures are often mistakenly self-diagnosed as hemorrhoids. Fissures are usually caused by the passage of hard feces or extreme diarrhea. Chron’s disease is recognized as a predisposing factor. Other factors include: previous anal surgery (such as hemorrhoidectomy) or the presence of another anorectal disease (hemorrhoids, anal stenosis, perianal fistula and others).

Patients often mistake anal fissures for hemorrhoids due to similar symptoms.

Anal fissure causes

Studies have shown that high resting tone and disturbance of the internal anal sphincter are also factors at work. The normal relaxation reflex of the internal anal sphincter is impaired and instead the patient might feel spasms (contractions of the sphincter muscle). The anal fissure tends to occur more often in younger men and women (range, 20-40 years). However, it can occur in any age and the sex distribution is equal. Anal fissures are most commonly located in the posterior midline (at 6 o’clock if we imagine the anus as an clock dial), less so in the anterior midline (at 12 o’clock, usually in women after childbirth).

Anal fissure symptoms

Patients with acute fissures complain of severe (pulsating) anal pain during and after the process of defecation. The pulsation is due to spasms of the internal anal sphincter. The pain usually lasts from several minutes to several hours. Some patients even claim that the pain is persisting all day. This feeling is compared to “passing razor blades” from the rectum. The severe anal pain often leads to fear from having a bowel movement. However, avoiding defecation is only going to do more harm. If you are delaying your bowel movements, the feces will harden and a fecal impaction (a hard mass of feces) might form, which will further worsen the condition.

Home remedies for anal fissure

The treatment of an anal fissure depends on its progression. Acute anal fissures are painful, but they might heal with conservative management. Sometimes fissures might heal on their own and the patient won’t even know that he had one. Clinical trials show that about 40% of the fissures can be healed with home remedies. To treat an acute anal fissure one should avoid constipation and hard stools. Hard feces and constipation can delay and setback the treatment or even lead to recurrence of the anal fissure. To achieve good results you should follow some simple steps that will make the stool bulky and soft:

  • Switch to high-fiber diet and drink at least 2l of water (or more depending on the weight).
  • Dip into hot water for 10-15 minutes, two-three times per day. The so-called “sitz baths” with warm water can have a soothing effect and are recommended if you experience pain after defecation.
  • Apply topical anesthetics (i.e. lidocaine) or even better – sphincter relaxing anal creams (i.e. diltiazem cream). Application of anal creams in the perianal region (outside the anus) has no effect on the fissure.
  • Taking natural stool softeners or bulk forming agents, such as psyllium fiber (usually sold as Metamucil or unprocessed bran will aid the effort.
  • Rectal suppositories can be used to soften hard stools or stools with hard tip. The suppositories can help you avoid further retearing. They will prompt you to defecate in 10-30 minutes after insertion.

Chronic anal fissure

An acute (fresh) anal fissure should heal in 4-6 weeks. If the fissure doesn’t heal, it will proceed to a chronic state (after 6-8 weeks). Chronic anal fissures are less painful, but severe symptoms tend to reoccur. Chronic fissures can develop the so-called sentinel piles. These small skin tags can persist permenently, even after the fissure has healed. In addition, a hyperthrophied anal papillae can appear in the anal canal. In a chronic fissure, the floor of the ulcer is actually uncovering the muscle fibers of the internal sphincter. Once the internal sphincter is bared with scarring and fibrosis, the fissure won’t be able to heal easily without an operation.

Anal fissure photos (click to see)
Chronic anal fissures are easy to spot.

Anal fissure treatment

One of the predisposing factors for the development of an anal fissure is the increased sphincter tone. This is why researchers have been purposing numerous topical, oral and injectable agents to lower the resting pressure and therefore – relax the sphincter until the fissure is healed. Some of the most popular agents include – glyceryl trinitrate (GTN/nitroglycerin), calcium channel blockersdiltiazem or nifedipine, and botulinum toxin, which is injected locally.

The available comparative data shows mixed results. However, most authors agree that all these agents are useful and can be employed as first-line treatment of anal fissures (the so-called “pharmacologic sphincterotomy”). Each agent has its proponents. The glyceryltrinitrate has been very popular during the 90s, but it has some drawbacks. Topical treatment with nitroglycerin may cause some side effects, such as headaches.

The calcium channel blockers have demonstrated similar effectiveness with lower frequency of side effects. There is less data available on these agents, but they have a growing support. Botulinumtoxin injections are also frequently applied for anal fissure treatment. The efficacy of the Botox treatment falls in long-standing chronic anal fissures. Surgical treatment has proven to be more effective in curing chronic fissures, with much less recurrences recorded.

Glyceryl trinitrate ointment for anal fissure

Many researchers have tried to demonstrate the beneficial effects of glyceryl trinitrate (GTN, nitroglycerin) for treatment of anal fissures. The nitroglycerin acts as a nitric oxide, which is the predominant neurotransmitter in the internal anal sphincter. The idea is that the release of nitric oxide is aiding the relaxation of the internal anal sphincter. Clinical trials have shown that the topical application of 0.2% or 0.4% glyceryl trinitrate ointment will lead to reduction of the pressure in the anal sphincter and thus promote faster fissure healing.

The topical glyceryl trinitrate ointment is to be applied for 4-8 weeks, with dosing frequencies varying from two to three times a day. The ointment should be applied inside the anal canal. Available data shows that it promotes healing in about 40-70% of the chronic anal fissures. Recurrence rates are relatively low (20-30%). Anal fissures with a long-standing history are less likely to heal (>6 months). However, the application of nitroglycerin has been associated with some significant adverse effects. Headache has been reported as the primary side effect from nearly 70% of the patients. Due to the headaches some patients might find it difficult to continue the treatment. In this case the physician might prescribe another topical solution.

Treatment of anal fissure with calcium channel blockers

Given the high frequency of side effects reported by patients treated with Glyceryl trinitrate ointment, researchers have started to evaluate the effects of calcium channel blockers (nifedipine or diltiazem) for treatment of anal fissures. Diltiazem is primarily used in the treatment of hypertension and some types of arrhythmia. It relaxes the smooth muscles in the walls of arteries, which improves the blood flow and lowers the blood pressure. The idea is that a diltiazem cream can be used to lower the resting anal pressure and promote fissure healing. The agent is available as oral preparation and in topical form. Studies have shown that the topical treatment with 2% diltiazem cream is much more effective and it will promote healing in about 70% of the fissures. The diltiazem solution has to be applied inside the anal canal every 6-12 h, preferably in the morning after defecation and in the evening.  The main side effects of the treatment with diltiazem are mild headaches, flushing of the face (or the limbs). The reports of side effects are very inconsistent, but they are to be expected in about 10% of the patients.

Nifedipine is a medication used to manage angina and high blood pressure. It’s usually administrated in oral form, but a topical solution can be prepared. Controlled trials have shown that topical nifedipine ointment is more effective in treatment of anal fissures than other gels and ointments available over-the-counter (usually containing lidocaine and hydrocortisone). Trials with 0.3% nifedipine ointment applied inside the anal canal every several hours have demonstrated improvement in 60% of the patients.

Topical treatment with diltiazem (or nifedipine) is usually administrated for 4 to 8 weeks. If there is no effect, the physician might purpose a surgical treatment of the anal fissure. Comparative studies have shown that Glyceryl trinitrate and the calcium channel blockers can both promote healing of anal fissures. The side effects are the main concern in treatment with glyceryl trinitrate based ointments and most researchers agree that the topical application of diltiazem/nifedipine solution should be preferred as first-line treatment.

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Botox for anal fissure

Botulinum toxin (also known as Botox) is a product of the diverse group of pathogenic bacteria clostridium botulinum. The relaxation effects of the botulinum toxin on the local muscles been examined extensively. Several researchers have suggested that it could be used in the treatment of anal fissure. The toxin is injected in the internal anal sphincter and causes paresis that lasts for weeks. This leads to a decrease in the anal resting pressure and promotes anal fissure healing.

The method of injection and the injection site of the botulinum toxin agent aren’t very well determined. Some physicians inject it in the external sphincter muscle and other inject it in the internal. One of the primary pathogenesis in anal fissure formation is the high resting pressure of the internal sphincter. That’s why the injection should be made in the internal sphincter. In patients with posterior fissure the injection could be made anteriorly. The botox injection for anal fissure is well tolerated and easy to perform as an outpatient procedure, that doesn’t require any time off. However, there is certain controversy over the safety and the side effects of the treatment of anal fissure with botox. Skin and allergic reactions, perianal hematomas and other complications have been recorder after anal fissure treatment with botox injection. Temporary incontinence has been noted in about 5-30% of the patients. Another problem is that there is no agreement on the optimal dose, which should be administrated. Some physicians are suggesting that 20 units injection of botulinum toxin should be used. If the fissure persist, higher doses can be administrated. Different studies have demonstrated that the botox injection is effective in about 70% of the cases. We can conclude that it is less effective than the operative solution. Unfortunately, relatively high recurrence rate has been recorded in the long-run (in 30-50% of the cases) after botox treatment.

Surgery for anal fissure

Fissures that don’t respond to the indicated medical treatment or don’t resolve on their own in about 6 weeks can be considered for surgical treatment. Both the patient and the physician should evaluate certain factors before proceeding. Failure of surgical treatment or recurrence of the anal fissure is possible. Impaired sphincter control after sphincterotomy is a major complication. Various procedures exists for the treatment of chronic or recurrent fissures. However, none of them can guarantee 100% results. These procedures include anal dilation, the classic excision of the fissure (fissurectomy), advancement flaps (anoplasty), and the lateral internal sphincterotomy (LIS).

Anal dilation (Lord’s procedure)

The procedure has been described in the 60s. It utilizes manual dilation of the anus with several fingers. The goal is to stretch the sphincter and reproduce a temporary paralysis of the muscle fibers. The procedure can be done with several fingers (4 to 8) or with other devices, such a retractor or rectosigmoid balloon. The idea is that it will extent the sphincter stretch without causing any wounds to the anal canal. Several complications following the anal dilation have attracted widespread criticism. The most concerning of them being the damage inflicted on the internal sphincter, which can lead to fecal incontinence. The reported disturbance of incontinence is in range from 0% to as high as 20%. The incidence of recurrence is rather high (10-50%). Proponents of the procedure have suggested a modified technique that utilizes anal dilators to stretch the sphincter. There is not enough data available to support this method. But patients might find it uncomfortable, given that cold foreign object has to be inserted into the anal canal on regular basis for several weeks.


The classic excision with or without division of the sphincter muscle is not frequently used procedure nowadays. The excision itself leaves the patient with a painful external wound that requires a long time to heal. Numerous studies report different complications after the procedure, including: bleeding, abscess formation, anal stenosis, and fecal incontinence. The procedure is otherwise effective with low recurrence rate (<5%).

Advancement flaps technique for treatment of anal fissure

This method combines excision of the anal fissure with advancement flap of the anoderm (also called anoplasty). The anal fissure is excised and then covered with sliding skin gaft with broad base. The anoplasty has several advantages. It’s relatively painless and the postoperative wound care is easier. The wound will also heal faster. Complications are relatively rare, most of them involve postoperative bleeding. However, the procedure is less effective than lateral internal sphincterotomy (LIS) for patients with high-pressure fissures (about 80% efficiency versus nearly 95% for LIS). Advancement flaps should be therefore employed for patients with low-pressure fissure or as a second line of surgical treatment for patients who have failed lateral sphincterotomy.

Lateral sphincterotomy for the treatment of anal fissure

The lateral internal sphincterotomy (LIS) is considered to be the gold standard for treatment of anal fissures all over the world. It’s also recommended by the American Society of Colon and Rectal Surgeons (ASCCRS). It was first introduced by Eisenhammer in 1951. The goal of the operation is to promote healing by decreasing the resting anal pressure and breaking the cycle of spasm and pain. There are some variations of the lateral sphincterotomy, it can be performed with an open or closed technique. The procedure itself is done under anesthesia (general or regional).

The open technique is not as popular these days. The surgeon would make a direct incision, exposing the intersphincteric groove. Then the internal sphincter would be carefully divided. The wound is closed with suture.

The closed technique utilizes a scalpel to laterally divide the internal sphincter. The division is usually up to linea dentata. The closed technique has been demonstrated as safer and less postoperative care is required.

However, both methods could lead to some complications. These include: postoperative hemorrhage, perianal abscess, anal fistula, prolapsed hemorrhoids, and fecal incontinence. The most serious of them being long-term fecal incontinence. Numerous studies have reported mixed results, with postoperative incontinence in ranges from 0% to 30%. Patients will usually complain of inability to control gas, mild soiling of the underwear or even uncontrolled bowel movements. Most of these complications are temporary and to be expected. The rate of persistent fecal incontinence is usually as low as 5%. Researchers have noted that the reason for incontinence after LIS surgery is the length of the incision and the amount of internal sphincter divided. The internal sphincterotomy should be tailored according to the patient’s needs, as in women the internal sphincter might be shorter due to anatomical differences of the anal canal. Careful examination is needed before the division. Special attention should be paid to women who gave vaginal birth, as incontinence rates are higher in this specific group.

Anal fissure surgery recovery and aftercare

Pain relief is immediate after the procedure. Studies have shown that LIS is effective in more than 95% of the cases. Hospital stay is short as the operation can be done as an outpatient procedure in the office. Recovery is light and lasts from 2 to 4 weeks. Physicians will usually see the patient 1 month after the procedure. The postoperative course is aimed at keeping the stool soft and easy to pass.

  • Switch to high-fiber diet and drink at least 64-70 oz (aprox. 2 litres) of water (or more depending on the weight).
  • Dip into hot water or sitz baths for 10-15 minutes, two-three times per day.
  • Additional topical agents are not required. The patient shouldn’t apply any other agents used for treatment of anal fissure without prescription.
  • Taking natural stool softeners of bulk forming agents, such as psyllium fibe or unprocessed bran will aid the effort.

Other complications after anal fissure surgery

Some complications may arise from the presence of other anorectal diseases, mainly large internal hemorrhoids. One of the complications after lateral sphincterotomy is prolapsing hemorrhoids. The surgeon should inform the patient and perform hemorrhoidectomy to excise any adjacent hemorrhoidal tissue. This will help avoid any further complications. If the chronic fissure has developed any sentinel piles or hypertrophied anal papillae, they can be removed.

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Article author
Dr. Trayan Seliminsky, Gastroenterology, Medical University-Varna

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