Can a Fissure Come Back After Surgery?

Anal fissures can come back after surgery, though the risk is relatively low. Across multiple studies of lateral internal sphincterotomy, the most common surgical procedure for chronic fissures, recurrence rates generally fall between about 3% and 11%. That means the vast majority of people who undergo surgery stay healed, but a meaningful minority do experience a return of symptoms months or even years later. What determines whether you end up in that unlucky group depends on the type of surgery, the surgeon’s technique, your anatomy, and what you do (or don’t do) afterward.

How Often Fissures Return After Sphincterotomy

Lateral internal sphincterotomy, or LIS, is the gold-standard surgical treatment for chronic fissures that have not responded to conservative care. It involves cutting a small portion of the internal anal sphincter muscle to reduce the elevated resting pressure that prevents healing. The procedure has high cure rates, but the reported recurrence numbers vary depending on how long researchers follow patients.

In one long-term study, recurrent fissures appeared in about 8% of patients, and two thirds of those recurrences healed with conservative management alone, meaning only a small fraction ultimately needed further surgery.¹ A large series of over 400 patients found an even lower recurrence rate of about 3.6%, though it also flagged that anterior fissures (those toward the front of the anal canal, more common in women) recurred at a strikingly higher rate.² A meta-analysis pooling data from randomized trials put the overall recurrence after LIS at about 3.7%.³ An older study with longer follow-up found somewhat higher rates around 10–12%, which may partly reflect how recurrence tends to creep up the longer you track patients.⁴

So if you’re looking for a single number, something in the range of 3–10% is a reasonable expectation for recurrence after sphincterotomy, depending on the study and how many years of follow-up are included. That compares very favorably with non-surgical options, as we’ll see below.

Why Fissures Come Back

A fissure recurring after surgery is not simply bad luck. There are identifiable reasons it happens, and understanding them can help you reduce the risk.

The most common surgical reason is an incomplete sphincterotomy. If the cut in the internal sphincter muscle is too shallow or too short, resting anal pressure may not drop enough to allow full and lasting healing. The muscle essentially “wins” over time, tightening back up and recreating the conditions that caused the original fissure. This is one reason some surgeons extend the cut further up the sphincter. But that creates a real tension with the other major concern: cutting too much muscle risks permanent changes to continence.

Beyond the surgical technique itself, patient-related factors play a significant role. Constipation and straining are the most obvious culprits. Hard stools passing through an anal canal that has been weakened by surgery can re-tear the lining, especially at the original fissure site where scar tissue forms. Chronic diarrhea can be just as irritating. One study found that only about 14% of fissure patients actually had infrequent, hard bowel movements as the stereotypical pattern, suggesting the triggers are more varied than most people assume.

Anterior fissures, which sit on the front wall of the anal canal, have a notably higher recurrence rate. In the large series mentioned earlier, two thirds of all recurrences occurred in patients with anterior fissures.² Anterior fissures are more common in women and can be associated with obstetric injury or anatomic differences in how the sphincter is supported at the front of the canal. When the sphincter is already thinner or weaker anteriorly, the surgery has less margin for error.

The Surgical Trade-Off Between Healing and Continence

Every sphincterotomy involves a balancing act. Cut more muscle, and the fissure is more likely to heal quickly and stay healed. Cut less, and you preserve more sphincter strength, but the fissure may not heal fully or may return. This trade-off is the central challenge in fissure surgery.

A randomized trial directly compared two approaches: cutting the sphincter up to the level of the fissure itself (a more conservative cut) versus cutting up to the dentate line (a longer, more aggressive cut). The longer cut produced faster pain relief and faster healing, but it came with a meaningful increase in postoperative continence changes. The researchers specifically cautioned about women with a history of obstetric trauma, in whom the sphincter may already be compromised.⁵

The numbers illustrate the contrast sharply. One study found that sphincterotomy up to the dentate line carried about an 11% rate of some postoperative incontinence, compared to 3% when the cut was limited to the height of the fissure.⁶ Most surgeons today lean toward the more conservative cut and accept the small additional recurrence risk rather than compromising continence. The reasoning is straightforward: a recurrent fissure can be treated again, but permanent incontinence is much harder to fix.

Open Versus Closed Sphincterotomy

LIS can be performed as either an “open” procedure (where a small incision is made in the skin to expose the sphincter before cutting it) or a “closed” procedure (where the muscle is divided through a small puncture using a blade passed under the skin). Patients often wonder whether one technique is more likely to lead to recurrence.

The evidence suggests the two approaches are broadly similar in outcomes. The meta-analysis of randomized trials found a slightly higher recurrence rate with closed LIS compared to open, but the difference was not statistically significant.³ A head-to-head trial comparing the two found recurrence rates of about 2% for open and 3% for closed, again without a meaningful statistical difference. Interestingly, incontinence was somewhat higher with the closed approach in that study, at about 5% versus 0% with the open technique.⁷ The reasoning is that the closed approach can sometimes lead to an incomplete or uneven cut, since the surgeon cannot directly see the muscle being divided. That said, the differences are small enough that surgeon experience and preference likely matter more than the technique label.

How Surgery Compares to Non-Surgical Treatments

For context on recurrence, it helps to know how surgery stacks up against the alternatives. The two most common non-surgical approaches for chronic fissures are topical nitroglycerin (or similar medications that relax the sphincter) and botulinum toxin injections.

Topical nitroglycerin can heal about 75% of chronic fissures, but the recurrence rate at nine months is striking: roughly 67%.⁸ That means two thirds of the fissures that healed with medication came back within less than a year. Botulinum toxin fares somewhat better initially but runs into similar problems with time. One randomized trial found that botulinum toxin and sphincterotomy looked roughly equivalent at six months, but by twelve months the botulinum group’s success rate had dropped to about 75% while the surgery group held steady at 94%.⁹ Another randomized trial confirmed that botulinum toxin had a significantly higher recurrence rate than LIS.¹⁰

The pattern is clear: surgery has the lowest recurrence of any treatment for chronic anal fissures. Non-surgical treatments are reasonable first steps, particularly for people who want to avoid the small continence risk of surgery, but their Achilles’ heel is durability. If you’ve already tried medication and the fissure returned, the recurrence numbers for surgery should be reassuring.

Advancement Flaps and Other Procedures

Not every fissure surgery involves cutting the sphincter. For patients where sphincterotomy poses too great a continence risk (such as women who have had obstetric injuries, people who have already had one sphincterotomy, or those with pre-existing weakness), advancement flap procedures offer an alternative. These involve moving a small flap of healthy tissue to cover the fissure wound, promoting healing without further weakening the sphincter muscle.

A large retrospective study found a recurrence rate of about 3.3% after anocutaneous advancement flap, with only 0.2% experiencing mild incontinence symptoms.¹¹ A smaller randomized trial comparing two types of advancement flaps (mucosal versus cutaneous) found an overall healing rate of 90%, though that trial had a limited number of patients.¹² These procedures are less commonly performed than sphincterotomy, but they fill an important niche for patients in whom cutting more sphincter muscle is not advisable.

What Happens If Your Fissure Does Come Back

A recurrence is frustrating, but it’s far from hopeless. The approach depends on what was done the first time and how much sphincter function remains.

Many post-surgical recurrences are mild enough to heal with conservative treatment: fiber supplementation, stool softeners, warm sitz baths, and topical medications. As noted in the long-term sphincterotomy study, about two thirds of recurrences after surgery responded to these measures without a second operation.¹

For those whose recurrence doesn’t respond to conservative care, a repeat sphincterotomy (redo-LIS) on the opposite side of the anal canal is an option. A study specifically examining redo sphincterotomy for surgically recurrent fissures reported a 98% healing rate, with only 4% developing minor incontinence (gas or slight seepage).¹³ Patients in that study reported significant quality-of-life improvements, with satisfaction scores averaging nearly 10 out of 10. A comparison study confirmed that redo-LIS produced reliable results in terms of both recurrence prevention and pain relief.¹⁴

Before a second surgery, surgeons typically assess sphincter integrity using imaging such as endoanal ultrasound. This helps determine how much sphincter muscle remains and whether another cut is safe or whether an advancement flap would be more appropriate. For some patients with recurrence, particularly those who already have signs of compromised sphincter function, botulinum toxin injection may be used as a bridge or alternative to additional surgery.

Preventing Recurrence After Surgery

What you do after the wound heals matters as much as the surgery itself. The fissure may be gone, but the conditions that caused it in the first place, whether that’s hard stools, straining, prolonged sitting on the toilet, or chronic tension in the pelvic floor, are still present unless you address them.

Dietary fiber is the single best-studied preventive measure. A double-blind, placebo-controlled trial found that patients who took a meaningful dose of unprocessed bran daily after healing had a recurrence rate of just 16%, compared to 60–68% in the low-dose and placebo groups.¹⁵ That’s a dramatic difference, and it underscores how much ongoing stool quality matters. If fiber supplements cause bloating or discomfort, increasing dietary fiber through whole grains, fruits, and vegetables can accomplish the same thing with better tolerability. Adequate water intake is the obvious companion strategy.

Beyond diet, avoiding straining is critical. Spending excessive time on the toilet (particularly while reading or using a phone) keeps the sphincter under sustained pressure and can contribute to both new fissures and recurrence. If constipation is a recurring problem despite fiber, osmotic laxatives can help keep stools soft without the dependency risks of stimulant laxatives.

The Pelvic Floor Connection

One area that has gained attention recently is the role of pelvic floor muscle tension in driving chronic fissures. In many patients, the problem isn’t just high sphincter pressure from the internal sphincter alone; the entire pelvic floor is overactive. These patients may clench their pelvic muscles habitually or in response to pain, creating a cycle where tension prevents healing and pain reinforces tension.

A randomized controlled trial found that pelvic floor physical therapy significantly reduced pelvic floor muscle tone in patients with chronic fissures, and healed the fissure in about 56% of patients, compared to 21% in the control group.¹⁶ Long-term follow-up of that same trial showed the benefits were sustained at one year, with lasting improvements in muscle tone, pain ratings, and quality of life.¹⁷

Pelvic floor therapy isn’t a substitute for surgery in severe cases, but it may be an underutilized tool for patients with recurrent fissures, particularly those whose muscle tension seems disproportionate to their anatomy. If you’ve had surgery and the fissure keeps returning, asking about pelvic floor evaluation is worth considering. The therapy typically involves biofeedback exercises that teach you to recognize and relax the pelvic floor muscles, and it carries essentially no risk of harm.

Quality of Life After Sphincterotomy

Chronic fissures are disproportionately miserable relative to their medical seriousness. The pain during and after bowel movements can dominate daily life, cause anxiety about eating, and disrupt sleep. So how much does surgery actually improve things beyond just healing the wound?

A study that tracked quality of life using validated scoring instruments found a substantial and significant improvement after sphincterotomy. By twelve months, only about 3% of patients had any measurable continence changes, and even among those few, overall quality-of-life scores were comparable to patients without complications. The one group that did not share in the improvement was patients whose fissures recurred, whose quality-of-life scores remained notably low.¹⁸ That finding highlights why recurrence, even when it’s technically uncommon, looms so large in patients’ minds. A healed fissure transforms daily life; a recurrent one puts you back where you started.

Wound Healing Complications That Mimic Recurrence

Not every return of symptoms after surgery is a true fissure recurrence. A couple of postoperative complications can produce similar pain and bleeding and get mistaken for a new fissure.

Keyhole deformity is one such complication. It occurs when the sphincterotomy wound heals in a way that leaves a small groove or divot in the anal canal, creating a pocket where moisture collects and the skin remains irritated. A case series from a high-volume center found keyhole deformity in about 15 out of nearly 800 sphincterotomy patients. Most required surgical correction with an advancement flap, though a couple healed with conservative care. The symptoms, persistent discomfort, minor soiling, and a sense that the fissure never fully healed, can convincingly mimic recurrence.

Anal abscess or fistula formation after sphincterotomy is another possibility. These are infections or abnormal channels that develop in the tissue around the surgical site, and they require their own treatment pathway. If you have worsening pain, swelling, or discharge after initially feeling better, the problem may not be a recurrent fissure at all but one of these secondary issues, which a colorectal specialist can distinguish on examination.

Emerging Treatments Worth Watching

A few newer approaches have shown early promise for fissure treatment, though their specific role in preventing post-surgical recurrence is still being worked out. Platelet-rich plasma (PRP) injection, which uses concentrated growth factors from your own blood, has shown encouraging results in a randomized trial. Patients receiving PRP alongside standard topical treatment had a 96% healing rate at six months, compared to 66% with topical treatment alone.¹⁹ Whether PRP could reduce recurrence specifically after sphincterotomy hasn’t been tested yet, but the underlying idea of improving wound healing and tissue quality at the fissure site is logical enough that larger trials are likely coming.

Combined approaches that pair a sphincter-relaxing agent (like botulinum toxin) with a tissue-repair component (like a flap or PRP) are also being explored for complex or multiply recurrent fissures. These aren’t standard practice yet, but for the small group of patients who have failed two or more treatments, they represent directions worth discussing with a specialist.