An anal fissure is a small, linear tear in the lining of the anal canal that often fails to heal due to excessive muscle tension. When conservative treatments fail, a chronic fissure is treated surgically to relieve the underlying pressure. The most common procedure is a Lateral Internal Sphincterotomy (LIS), which is highly effective in promoting long-term healing. Patients often wonder if this painful condition can return, a question dependent on the mechanics of the surgery and the patient’s self-care.
The Mechanism of Surgical Healing
Chronic anal fissures are caused by a vicious cycle of pain, muscle spasm, and reduced blood flow. The internal anal sphincter, a muscle that operates involuntarily, spasms when irritated, creating high pressure in the anal canal. This elevated pressure constricts local blood vessels, starving the tissue of the oxygen and nutrients needed for repair.
Surgery is designed to break this cycle by targeting muscle tension. A Lateral Internal Sphincterotomy (LIS) involves making a precise, controlled cut in a small portion of the internal sphincter muscle. This division immediately lowers the resting pressure within the anal canal.
The decrease in pressure allows blood vessels to dilate, substantially increasing blood flow to the site of the tear. With improved circulation and lower mechanical stress, the chronic wound is able to receive the necessary cellular components to close and heal permanently. The procedure creates the optimal biological environment for the body to complete the healing process, typically leading to a successful outcome within a few weeks.
Probability of Recurrence and Contributing Factors
The success rate of Lateral Internal Sphincterotomy (LIS) is consistently high, making it the standard surgical treatment for chronic fissures. Studies show that LIS leads to successful healing in approximately 96% to 99% of patients. Consequently, the probability of the fissure returning after a successful procedure is low, with recurrence rates generally falling within a range of 1% to 9%.
A primary cause for recurrence is the persistence of the underlying problem. In some cases, the initial sphincterotomy may have been inadequate, meaning an insufficient portion of the hypertonic muscle was divided to fully relieve the pressure. If the internal sphincter’s tension remains too high, the cycle of spasm and ischemia can re-establish itself over time.
Recurrence can also be a sign of an underlying systemic condition that was not initially identified. Fissures not located in the typical posterior or anterior position may suggest conditions like Crohn’s disease or other inflammatory bowel diseases. These secondary causes require specific medical management, and surgical repair alone cannot prevent the tear from returning if the underlying inflammatory process is not controlled.
Another factor involves the formation of excessive scar tissue at the surgical site. This dense, non-elastic tissue can become a new source of rigidity and tension in the anal canal. Mechanical stress from passing a hard stool can then cause a new tear adjacent to the healed area, mimicking a recurrence of the original fissure.
Sustaining Healing Through Lifestyle Management
While the mechanical correction provided by surgery is effective, long-term success relies on preventing trauma from bowel movements. The most important daily preventative measure is maintaining soft, bulky stool consistency to ensure smooth passage. This is achieved through a high-fiber diet, with a recommended daily intake of 25 to 35 grams of fiber from sources like whole grains, fruits, and vegetables.
Adequate fluid intake is equally important, as fiber absorbs water to add bulk and softness to the stool. Without sufficient hydration, a high-fiber diet can lead to hard, difficult-to-pass stools that can tear the delicate lining. Drinking plenty of water throughout the day helps the fiber work effectively, creating a smoother process for defecation.
Patients should actively avoid straining during bowel movements, which creates high pressure and can re-injure the healed site or cause a new tear. Limiting time spent sitting on the toilet to five minutes or less is a practical way to reduce pressure on the anal canal. Using warm water soaks, known as sitz baths, after a bowel movement can also soothe the area and promote muscle relaxation.
Regular physical activity helps stimulate normal bowel function and prevents the sluggish movement that can lead to constipation. Recognizing the earliest signs of discomfort or slight bleeding and consulting a physician promptly is advisable, as minor adjustments to diet or the temporary use of a stool softener can often prevent a small irritation from progressing into a full recurrence.