Does Pelvic Floor Dysfunction Cause Typical Anal Fissures?
Pelvic floor dysfunction does not cause typical anal fissures, but it is a significant contributing factor that perpetuates and prevents healing of chronic fissures through increased internal anal sphincter tone and dyssynergia. 1, 2
Understanding the Relationship
The exact etiology of typical anal fissures remains incompletely understood, but the evidence points to a multifactorial process rather than a single causative mechanism 1:
Mechanical trauma alone is insufficient to explain anal fissure development, as less than 25% of patients with anal fissures actually complain of constipation or report passage of hard stools 1, 3
Internal anal sphincter hypertonia is strongly correlated with decreased anodermal vascular blood flow, supporting the ischemic ulcer theory as a primary pathophysiologic mechanism 1, 3
Pelvic floor dysfunction is present in a large percentage of patients with chronic anal fissures, manifesting as dyssynergia and increased pelvic floor muscle tone 2
The Clinical Evidence
The most compelling recent evidence comes from a 2022 randomized controlled trial that directly examined this relationship 2:
140 patients with chronic anal fissure and documented pelvic floor dysfunction were randomized to receive pelvic floor physical therapy with EMG biofeedback versus delayed treatment 2
Pelvic floor physical therapy significantly improved resting EMG values (p < 0.001) and demonstrated superior outcomes compared to controls across all measures 2
Fissure healing occurred in 55.7% of the intervention group versus only 21.4% in controls, with sustained improvements at 20-week follow-up 2
This provides strong evidence that pelvic floor dysfunction perpetuates chronic fissures and that addressing it facilitates healing 2
The Pathophysiologic Sequence
Based on the available evidence, the relationship appears to be:
Initial fissure development likely results from the combination of mechanical trauma, sphincter spasm, and local ischemia 4
Pelvic floor dysfunction then perpetuates the fissure by maintaining elevated sphincter tone and preventing adequate blood flow for healing 2, 5
This creates a vicious cycle where pain leads to sphincter spasm, which worsens ischemia and prevents healing 5, 4
Clinical Implications for Typical Fissures
Typical anal fissures are defined by their location (90% posterior midline, with anterior fissures in 10% of women versus 1% of men) and should not be confused with atypical fissures that suggest underlying pathology 1, 6, 3
For typical fissures, the treatment approach should address pelvic floor dysfunction 2:
Acute fissures should receive conservative management including dietary fiber, increased water intake, and sitz baths as first-line treatment 1, 6
Chronic fissures (persisting >8-12 weeks) benefit from pelvic floor physical therapy as adjuvant treatment alongside standard conservative measures 2, 7
Surgical sphincterotomy remains indicated for chronic fissures unresponsive to 8 weeks of medical management, as it directly addresses the sphincter hypertonia 6, 8
Common Pitfalls to Avoid
Do not assume all patients with fissures have constipation as the primary problem—the majority do not report this symptom 1, 3
Do not perform manual anal dilatation, which carries up to 30% risk of temporary incontinence and 10% risk of permanent incontinence 9
Do not overlook pelvic floor dysfunction assessment in patients with chronic or recurrent fissures, as this treatable component may be preventing healing 2