At a glance
If you are considering LIS for a chronic fissure, the question of incontinence is probably weighing heavily on your mind. It is the most common fear people describe. It is also the most common reason people delay a procedure that has a high chance of resolving months or years of pain.
This guide covers what the research actually says, what people who have had LIS describe, the difference between gas control and fecal continence, the factors that affect individual risk, and the real cost of letting this fear delay treatment.
It is not here to dismiss the concern. Incontinence risk is real. But the gap between what people fear and what most people experience is significant, and understanding that gap is part of making an informed decision.
What the research says vs what the forums fear
Forum discussions about LIS and incontinence tend to amplify the worst outcomes. This is natural — people who had surgery without issues are less likely to post than people who had complications. What you read online is not a representative sample. It is weighted towards the difficult experiences.
Here is what large-scale research reviews generally report:
- Fecal incontinence — involuntary loss of stool — is uncommon after LIS. Most large studies report rates in the low single digits.
- Gas control changes — reduced ability to hold gas — are more commonly reported, particularly in the early weeks. Published rates vary widely depending on how the question is asked and when it is asked after surgery.
- Any continence disturbance — when studies use broad definitions that include any change in gas control, urgency, or soiling — reported rates range from roughly 5 to 15 percent across major reviews.
- Most changes are minor — when continence changes are reported, they are overwhelmingly described as minor and manageable rather than severe.
The number that circulates most often in forums is the low-end figure — sometimes cited as less than 1 percent for fecal incontinence from NHS data. This is not wrong, but it reflects a specific definition and a specific study. The honest answer is that the range depends on how you measure it and who you ask.
What the research consistently shows is that most people who have LIS do not experience significant continence problems. A minority experience some change — usually in gas control. A small number experience persistent issues that affect daily life.
Temporary changes vs permanent changes
This distinction matters because people often hear “incontinence risk” and imagine the worst-case scenario as permanent. Here is how it tends to break down.
What tends to be temporary
- Early gas control issues — many people notice reduced gas control in the first 2 to 6 weeks. The sphincter has just been partially cut and is healing. The body has not yet adapted.
- Urgency — some people describe a temporarily reduced window between feeling the urge and needing to reach a toilet. This tends to improve as healing progresses.
- Minor soiling — a small number of people report occasional minor soiling in the early weeks, particularly with loose stools. This is usually self-limiting.
What can be permanent
- Slight reduction in gas control — some people describe a lasting, minor change in their ability to hold gas. They can still control it most of the time, but there is less margin than before.
- Reduced urgency window — a small number of people describe a permanent slight reduction in how long they can comfortably wait after feeling the urge to go.
- Significant fecal incontinence — this is rare, but it does happen. It is more likely in people with pre-existing risk factors.
The majority of people who report any change describe it as temporary or minor and permanent. The severe, life-altering incontinence that people fear when they picture “walking around in a diaper” is a very uncommon outcome.
Gas control vs fecal continence
These are different things, and conflating them is where a lot of the fear comes from.
Gas control refers to the ability to hold gas and choose when to release it. The internal sphincter — the muscle that LIS partially cuts — plays a role in this. Some reduction in gas control is the most commonly reported continence change after LIS.
Fecal continence refers to the ability to control the passage of stool. This involves multiple mechanisms — the external sphincter (which LIS does not touch), the pelvic floor muscles, rectal sensation, and stool consistency. Fecal continence after LIS is preserved in the vast majority of people.
When someone in a forum says “I lost continence after LIS,” it is worth understanding what they specifically mean. In most cases, they are describing gas control changes, not fecal incontinence. Both are valid concerns, but they are very different experiences in terms of daily impact.
What gas control changes look like in practice
People who describe lasting gas control changes after LIS tend to report:
- Occasionally not being able to hold gas in situations where they previously could
- Gas passing with less warning than before
- Needing to be slightly more aware of gas sensations
- Some uncomfortable moments in social settings, particularly in the first few months
Most of these people also describe the change as a trade-off they would make again. When the alternative was months or years of daily fissure pain, a slight reduction in gas control was, in their view, an acceptable price.
Risk factors that increase the chance
Not everyone faces the same level of risk. Several factors are known to affect the likelihood of continence changes after LIS.
Previous anal surgery
If you have had previous surgery in the anal area, including a prior sphincterotomy, your residual sphincter function may already be reduced. A second procedure that further reduces muscle mass carries higher risk.
Vaginal deliveries
Multiple vaginal deliveries can affect sphincter integrity and pelvic floor function. This is one reason some surgeons are more cautious about recommending LIS to women who have had several births, and may prefer fissurectomy with botox instead.
Age
Sphincter function naturally decreases with age. Older adults may have less reserve capacity, meaning even a small reduction has more noticeable effects.
Pre-existing sphincter damage or weakness
Conditions or injuries that have already compromised the sphincter — whether from previous surgery, obstetric injury, or other causes — increase the risk profile.
Surgeon assessment matters
This is why the pre-operative conversation with your surgeon is so important. A good surgeon will assess your specific anatomy, ask about your history, and in some cases use investigations like endoanal ultrasound to evaluate sphincter integrity before recommending a procedure.
If your surgeon does not raise these factors, you should. The questions to ask are straightforward:
- Given my history, what is my individual risk?
- Do you recommend any investigations to assess my sphincter before surgery?
- Would fissurectomy with botox be more appropriate for my risk profile?
What people who had LIS actually describe
Across the many accounts people share, some consistent patterns emerge about continence after LIS.
The majority report no significant change
Most people who have LIS describe their continence as unchanged or only very mildly affected. These accounts are less dramatic and therefore less visible in forums, but they represent the most common outcome.
Early anxiety is nearly universal
Even people who ultimately have no continence issues describe being hypervigilant about it in the early weeks. Every sensation is scrutinised. Every moment of gas becomes a test. This anxiety itself can be distressing, and it tends to fade as confidence builds.
Gas control issues that resolve
A common pattern: reduced gas control in weeks 1 to 4, gradual improvement over months 2 to 3, and return to something close to normal by month 3 to 6. People describe learning to trust their body again during this period.
Minor permanent changes that are accepted
Some people describe a lasting slight reduction in gas control that they notice but that does not significantly affect their daily life. The common sentiment is: “It is not perfect, but compared to what I was living with, it is nothing.”
The rare difficult outcome
A small number of people describe persistent continence changes that do affect their daily life. These accounts are real, they are distressing, and they deserve to be acknowledged. They are also uncommon, and they are more likely in people with identifiable risk factors.
Does botox carry the same risk?
No. Botox and LIS affect the sphincter in fundamentally different ways.
Botox temporarily relaxes the sphincter muscle. Its effect wears off over 2 to 3 months. Any continence changes that occur during this period are typically temporary and resolve as the botox effect fades.
LIS permanently cuts a portion of the sphincter muscle. The change is structural and lasting. The body adapts, but the muscle does not regenerate.
For people who are particularly concerned about incontinence risk, this distinction is often central to their treatment decision. Fissurectomy combined with botox offers a way to address a chronic fissure without permanently altering the sphincter. The trade-off is that success rates for fissurectomy with botox, while good, are generally reported as somewhat lower than for LIS.
This is a nuanced decision and one of the most valuable conversations you can have with your surgeon.
How fear of incontinence delays treatment
This is worth addressing directly, because the delay itself has a cost.
People commonly describe spending months — sometimes over a year — putting off a decision about LIS because of incontinence fear. During that time:
- The fissure continues to cause daily pain
- Quality of life remains significantly affected
- The cycle of fear around bowel movements continues
- Emotional wellbeing deteriorates
- Work, relationships, and daily activities are curtailed
- Some people develop secondary issues like anxiety, depression, or disordered eating from food avoidance
The incontinence concern is valid. It should be taken seriously. It should be discussed thoroughly with a surgeon. But when the fear of a low-probability outcome prevents someone from addressing a condition that is causing certain, daily suffering, the calculus deserves honest examination.
People who eventually have LIS and recover well overwhelmingly describe their primary regret as waiting too long. Not because the fear was silly — it was not — but because the months spent paralysed by that fear were months of unnecessary pain.
This is not pressure. If you are not ready, you are not ready, and that is okay. But if the only thing standing between you and treatment is the word “incontinence,” it is worth making sure you fully understand what that risk actually looks like for someone with your specific history and anatomy.
Preparing for the conversation with your surgeon
If incontinence risk is your primary concern — and for many people it is — make it the focus of your pre-operative conversation. Your surgeon should be willing to discuss it in detail.
Questions that people find helpful:
- What is the incontinence risk for someone with my specific history? — Not general statistics. Your risk, based on your anatomy, your births, your previous surgeries, your age.
- Do you recommend any investigations before surgery? — Endoanal ultrasound, for example, can assess existing sphincter integrity.
- What type of sphincterotomy do you perform? — Tailored (partial) sphincterotomy, where the cut length is matched to the fissure length, is associated with lower continence risk than a full-length division.
- Would fissurectomy with botox be appropriate for me? — Understanding whether there is a sphincter-preserving alternative for your situation.
- If continence changes did occur, what would management look like? — Knowing there are options (pelvic floor exercises, dietary management, specialist referral) can reduce the fear of an unknowable outcome.
- What is your own experience with continence outcomes? — A surgeon’s personal data is more relevant to your decision than published averages.
If your surgeon dismisses the concern or does not engage with it thoroughly, that is worth noting. This is a legitimate worry that deserves a detailed, personalised answer.
Talking to your doctor
If you are currently living with a chronic fissure and the fear of incontinence is the primary barrier to considering surgery, bring that specific concern to your next appointment. A good surgeon or specialist will not minimise it. They will assess your individual risk, discuss alternatives, and help you understand what the realistic outcomes look like for someone in your situation.
If you have already had LIS and are experiencing continence changes that concern you, speak with your surgeon. Early assessment and intervention — including pelvic floor physiotherapy — can make a meaningful difference. Changes in the early weeks are common and often improve. But if something does not feel right, you deserve to have it addressed rather than dismissed.
If you are trying to organise your thoughts before an appointment, our AI experience navigator offers a private, anonymous space to talk through what you are worried about. It does not give medical advice, but it can help you articulate your concerns and prepare your questions.