Lateral Internal Sphincterotomy: Impact on Anal Sexual Function vs Continence

Understanding the Dual Impact

The World Journal of Emergency Surgery identifies altered sensations and sexual dysfunction following LIS as primarily neuropathic pain and dysesthesia rather than structural sphincter damage 1
Patients with sexual dysfunction typically have intact continence and altered sensations rather than mechanical problems 1
Pelvic floor muscle tension commonly develops after anorectal surgery and contributes to altered sensations during sexual activity 1

Specialized pelvic floor physical therapy, 2-3 times weekly focusing on internal and external myofascial release, is recommended for post-LIS sexual dysfunction 1
Topical lidocaine 5% ointment can be applied to affected areas for neuropathic pain management 1
Gradual desensitization exercises, guided by a physical therapist, can help improve sexual function 1
Warm sitz baths can promote muscle relaxation and reduce symptoms 1
Muscle coordination retraining can help reduce protective guarding patterns that developed during the painful fissure period 1

Botulinum toxin injection represents a safe alternative to LIS, achieving 75-95% cure rates with no risk of permanent incontinence or sexual dysfunction 2, 3
The mechanism of botulinum toxin involves temporary paresis of the anal sphincter, reducing resting tone and allowing fissure healing through reversible sphincter relaxation without permanent damage 3
Botulinum toxin should be considered after 8 weeks of failed topical therapy, with calcium channel blockers as the first-line treatment and nitroglycerin as the second-line treatment 4, 3

Additional surgical interventions should not be pursued for post-LIS sexual dysfunction, as this would likely worsen the neuropathic component 1
Manual anal dilatation should be avoided entirely, as it carries a 30% temporary and 10% permanent incontinence rate 5
The distinction between sexual dysfunction after LIS being typically neuropathic/myofascial rather than mechanical sphincter failure should be recognized, requiring physical therapy rather than surgical revision 1

Continence after anorectal procedures depends chiefly on the resting tone generated by the internal anal sphincter (IAS), which provides the majority of anal sphincter resting pressure, together with voluntary contraction of the external anal sphincter (EAS)【6】.
During surgical repair the IAS should be identified and re‑approximated because it supplies most of the resting tone necessary to maintain continence【6】.

Botulinum toxin injection is a safe alternative to lateral internal sphincterotomy, producing cure rates of approximately 75‑95 % while avoiding permanent incontinence or sexual dysfunction【7】.

Internal and external myofascial release targeting pelvic floor trigger points and muscle contractures is a core component of pelvic floor physical therapy for patients with post‑LIS/fistulotomy pain and dyssynergia. 8

The American Gastroenterological Association advises the use of manual physical‑therapy techniques that resolve pelvic, abdominal, and hip muscular trigger points, lengthen contractures, and release painful scar or connective‑tissue restrictions in individuals presenting with pelvic‑floor tenderness. (Expert consensus) 8
Pelvic‑floor strengthening (Kegel) exercises should be avoided in patients with pelvic‑floor tenderness because they may exacerbate muscle tension and spasm. (Expert consensus) 8

A randomized controlled trial demonstrated that 59 % of patients receiving myofascial physical therapy reported moderate or marked improvement at 3 months, compared with 26 % of patients receiving general therapeutic massage, indicating a significant superiority of the targeted myofascial approach. (Level I evidence) 8

Patients should seek a pelvic‑floor physical therapist who has specific training in anorectal dysfunction and internal myofascial release techniques to ensure appropriate management of post‑surgical pelvic‑floor disorders. (Expert consensus) 8