-Connie Pennington, MD
Acute anal fissures, or tears in the anoderm, are the most common cause of acute anal pain. An anal fissure is a small, oval-shaped tear in the skin that lines the opening of the anus. Fissures typically cause severe pain and bleeding with bowel movements. Fissures are quite common, but are often confused with other causes of pain and bleeding, such as hemorrhoids. Anal fissures can occur at any age and have an equal gender distribution. Most fissures occur in the posterior midline, or back of the anus, while fewer occur in the anterior midline, or front of the anus. A small number of patients may actually have fissures in both the front and the back locations. Fissures located elsewhere, like off to the sides of the anus, raise suspicion for other diseases and should be examined further.
The typical symptoms of an anal fissure include pain and bleeding with bowel movements. Patients note severe pain during and especially after a bowel movement, lasting from several minutes to a few hours. Patients often notice bright red blood from the anus that can be seen on the toilet paper or on the stool. Between bowel movements, patients with anal fissures are often relatively symptom-free. Many patients are fearful of having a bowel movement and may try to avoid defecation secondary to the pain.
Fissures are usually caused by trauma to the inner lining of the anus. A hard, dry bowel movement is typically responsible, but loose stools and diarrhea can also be the cause. The inciting trauma to the anus produces severe anal pain, resulting in anal sphincter spasm and a subsequent increase in anal sphincter muscle pressure. The increase in anal sphincter muscle pressure results in a decrease in blood flow to the site of the injury, thus impairing healing of the wound. Ensuing bowel movements result in more pain, more anal spasm, diminished blood flow to the area, and the cycle is propagated. Treatment strategies are aimed at interrupting this cycle to promote healing of the fissure.
Anal fissures may be acute (recent onset) or chronic (typically lasting more than 8-12 weeks). Acute fissures may have the appearance of a simple tear in the anus, whereas chronic fissures may have swelling and scar tissue present. Chronic fissures may be more difficult to treat and may also have an external lump associated with the tear, called a sentinel pile or skin tag, as well as extra tissue just inside the anal canal, referred to as a hypertrophied papilla.
Quite commonly, anal fissures are misdiagnosed as hemorrhoids due to some similar symptoms between the two. This delay in diagnosis may lead to an acute fissure becoming a chronic one and becoming more difficult to treat. Misdiagnosis of an anal fissure may also allow other conditions to go undetected and untreated, such as serious infections or even cancer. These less common causes of fissures include inflammatory conditions and certain anal infections, such as Crohn’s disease, ulcerative colitis, syphilis, tuberculosis, leukemia, HIV/AIDS, or anal cancer. These diseases cause atypical fissures that are often located off the midline, are multiple, painless, or nonhealing after proper treatment.
The majority of anal fissures do not require surgery. The most common treatment for an acute anal fissure consists of making one’s stool more formed and bulky with a diet high in fiber as well as utilizing over-the-counter fiber supplementation (totaling 25-35 grams of fiber/day). Stool softeners and increasing water intake may be necessary to promote soft bowel movements and aid in the healing process. Topical anesthetics, such as lidocaine, can be used for anal pain and warm tub baths (sitz baths) for 10-20 minutes several times a day (especially after bowel movements) are soothing and promote relaxation of the anal muscles, helping the healing process. Narcotic pain medications are not recommended for anal fissures as they promote constipation. These non-operative measures will help achieve resolution of pain and bleeding, and potentially heal greater than half of acute fissures.
Stress reduction is also important. Fissures are often seen in the "type A personality" and can be related to stress. Some stress manifests as a tightening of the muscles of the pelvis, even when one is unaware of this happening. Muscle relaxation techniques and breathing exercises can become very important in the conscious release of tension.
Sometimes medications typically used for hypertension can be compounded by your pharmacist into ointments or creams that, when applied to the anus, reduce the anal resting pressure, allowing increased blood flow to the site and promoting the healing of fissures. Nitroglycerin ointment was first used, but due to the side effect of headaches, compliance was poor. Calcium channel blockers, like diltiazem cream, are more commonly prescribed and does not cause headache. Many patients experience near-complete healing of anal fissures with this approach.
Fissures can recur easily, and it is quite common for a fully healed fissure to recur after a hard bowel movement or other trauma. Even when the pain and bleeding have subsided, it is very important to continue good bowel habits and a diet high in fiber as a lifestyle change. If the problem returns without an obvious cause, further assessment may be warranted.
A fissure that fails to respond to conservative measures should be re-examined. Persistent hard or loose bowel movements, scarring or spasm of the internal anal muscle all contribute to delayed healing. Other medical problems such as inflammatory bowel disease (Crohn’s disease), infections or anal tumors can cause symptoms similar to anal fissures. Patients suffering from persistent anal pain should be examined to exclude these diseases. This may include a colonoscopy and an exam in the operating room under anesthesia with biopsies and tissue cultures.
Surgery for an anal fissure is a Lateral Internal Sphincterotomy. This is where a portion of the anal canal muscles are carefully cut, to allow relaxation of the anal canal. The anal canal muscles are round, and if there is a tear (fissure), the muscles are pulling from both sides on the tear. The cut is a counter-incison to reduce anal canal pressure. The fissure generally heals on its own. If there are associated skin tags, they may be removed as well.
Precise and controlled partial division of the internal anal sphincter muscle is a highly effective and commonly used method to treat chronic and refractory anal fissures, with success rates reported to be over 90%. Recurrence rates after sphincterotomy are exceedingly low when properly performed by a surgeon. The surgery is performed as an outpatient, same-day procedure. The main risks of internal sphincterotomy are variable degrees of stool or gas incontinence, and this is why patient selection is important, as is the surgery itself. A woman may tear the same group of muscles during childbirth, and caution is used in women of childbearing age. Patients undergoing sphincterotomy generally notice decreased pain with the next bowel movement. Healing is usually rapid and patients may resume daily activities and return to work in just a couple days.
All surgical procedures carry some risk of bleeding and infection, and can rarely interfere with one’s long-term ability to control gas and stool. The most important factors are pre-exisitng conditions. Special consideration is given to patients with established anal incontinence, known anal sphincter muscle injury (such as after obstetric injury) or diarrheal conditions (i.e. Crohn’s disease or Celiac diseasse). In these select patients, surgical sphincterotomy must be considered carefully. A thorough discussion preoperatively will identify any of these risk factors so that the most appropriate treatment can be provided. If you suffer from an anal fissure, please discuss all treatment options with a colorectal surgeon.