At a glance
If you have been recommended LIS surgery but do not experience the painful spasms that others describe, it is natural to wonder whether the surgery makes sense for your situation. This guide addresses that specific question.
The role of spasm in fissure disease
The classic explanation of chronic anal fissure involves a cycle: the fissure causes pain, pain triggers sphincter spasm, spasm reduces blood flow, reduced blood flow prevents healing, and the fissure persists.
LIS works by interrupting this cycle — cutting a portion of the sphincter muscle to reduce the spasm and restore blood flow.
When spasm is not obvious
Not everyone experiences spasm in the same way. Some people have:
- Elevated resting tone without obvious spasm — the muscle is chronically tight, but there are no dramatic clenching episodes
- Spasm that they do not recognise — the tension has been present so long it feels normal
- Mild spasm relative to others — enough to impair healing but not enough to cause the intense post-bowel-movement episodes others describe
- Low or normal sphincter pressure — the fissure persists for reasons other than spasm
What manometry tells you
Anorectal manometry is a test that measures the pressure in the anal canal. It provides objective data about:
- Resting sphincter pressure (the baseline tone)
- Squeeze pressure (the voluntary contraction)
- The relationship between the two
If your resting pressure is elevated, LIS has a clear rationale — reducing that pressure should improve blood flow and healing conditions.
If your resting pressure is already normal or low, the picture is less clear. LIS would reduce an already normal pressure, which may not improve healing and could increase continence risk without corresponding benefit.
The conversation with your surgeon
If you are scheduled for LIS but have concerns about the absence of spasm, these questions are worth raising:
- Have you assessed my resting sphincter pressure?
- Is manometry appropriate before we proceed?
- Given my specific presentation, is LIS the best approach?
- Are there alternative approaches that might be more appropriate for my situation?
- What is the evidence for LIS when resting pressure is not significantly elevated?
A good surgeon will welcome these questions. The goal is to choose the treatment that matches your specific anatomy and physiology, not to follow a one-size-fits-all pathway.
Alternative considerations
If LIS is not the right fit, options that may be discussed include:
- Botox injection — temporary sphincter relaxation to assess whether reducing tone helps healing
- Fissurectomy — removing the chronic fissure tissue to promote fresh healing
- Investigation for other causes — Crohn’s disease, pelvic floor dysfunction, or other conditions that impair healing
- Extended conservative care — with optimised stool management and topical treatment
The absence of obvious spasm does not mean treatment is impossible. It means the right treatment may look different.