Does pelvic floor dysfunction cause atypical anal fissures?

Does Pelvic Floor Dysfunction Cause Atypical Anal Fissures?

Pelvic floor dysfunction does not cause atypical anal fissures; rather, atypical fissures indicate serious underlying pathology such as inflammatory bowel disease, sexually transmitted infections, anorectal cancer, or tuberculosis that must be ruled out. 1

Understanding Atypical vs. Typical Anal Fissures

Location and characteristics distinguish atypical from typical fissures:

• Approximately 90% of typical anal fissures are located posteriorly in the midline, while anterior fissures occur in 10% of women versus 1% of men 1
• Atypical fissures are lateral in location or multiple in number, which should immediately raise suspicion for associated diseases 1
• When atypical fissures are present, you must investigate for inflammatory bowel disease (IBD), sexually transmitted diseases (HIV, syphilis, herpes), anorectal cancer, or tuberculosis 1

The Relationship Between Pelvic Floor Dysfunction and Anal Fissures

While pelvic floor dysfunction does not cause atypical fissures, there is an important bidirectional relationship:

Pelvic floor dysfunction commonly coexists with chronic anal fissures:

• A large percentage of patients with chronic anal fissures experience pelvic floor dysfunction, specifically dyssynergia and increased pelvic floor muscle tone 2
• In one randomized controlled trial, 140 patients with chronic anal fissure demonstrated significant pelvic floor dysfunction that improved with targeted pelvic floor physical therapy 2
• The exact etiology of typical anal fissures involves internal anal sphincter (IAS) hypertonia and decreased anodermal vascular blood flow, not pelvic floor dysfunction per se 1

Chronic straining is a shared risk factor:

• Chronic straining during defecation is a risk factor for both pelvic floor dysfunction and hemorrhoids, but this represents a common predisposing factor rather than a causal pathway to atypical fissures 3, 4

Clinical Approach to Atypical Fissures

For patients with atypical anal fissures, the WSES-AAST guidelines recommend:

• Collect a focused medical history and perform complete physical examination 1
• Perform laboratory tests based on suspected associated illness 1
• Conduct investigations (endoscopy, CT scan, MRI, or endoanal ultrasound) only when there is suspected concomitant inflammatory bowel disease, anal or colorectal cancer, or occult perianal sepsis 1

Treatment Implications

If pelvic floor dysfunction is identified alongside chronic anal fissures:

• Pelvic floor physical therapy including electromyographic biofeedback is highly effective, with 55.7% healing rates compared to 21.4% in controls 2
• This therapy significantly improves resting electromyographic values, reduces pain, diminishes dyssynergia, and decreases pelvic floor muscle tone 2
• Pelvic floor physical therapy should be considered as adjuvant treatment alongside regular conservative management for chronic anal fissures with documented pelvic floor dysfunction 2

Key Clinical Pitfall

The critical error is attributing atypical fissures to pelvic floor dysfunction and missing serious underlying pathology. Lateral or multiple fissures demand investigation for malignancy, IBD, or infection—not reassurance that pelvic floor dysfunction is the culprit 1, 5. Secondary fissures require further investigation and multidisciplinary management, particularly when malignancy is suspected 5.