Understanding the Patient's Pelvic-Floor-Driven Sexual Sensation
The Physiological Mechanism
The sensation your patient describes—a wave-like arousal triggered by voluntary pelvic floor contraction—is mediated by the bulbocavernosus muscle (BCM), which is anatomically continuous with the external anal sphincter (EAS) and plays a direct role in erectile function and sexual response. 1
The BCM functions as a "suction-ejection pump" during sexual activity by:
- Compressing the penile bulb and dorsal penile vein to enhance rigidity 1
- Generating rhythmic contractions that contribute to orgasmic sensation 1
- Responding to voluntary pelvic floor engagement, which your patient was able to consciously trigger before his injury 1
This explains why he could previously "imagine his rectal and/or pelvic region constrict or contract" and experience heightened arousal—he was voluntarily activating the BCM-EAS complex. 1
How Anal Fissure Disrupts This Sensation
The Pain-Spasm-Dysfunction Cycle
Anal fissures cause internal anal sphincter (IAS) hypertonia and painful spasm that radiates to the penis and is exacerbated during erection and sexual activity, directly interfering with the BCM's function. 1
In a study of 32 men with acute anal fissures and 21 with chronic fissures:
- All men with acute fissures developed erectile dysfunction that had not existed before the fissure 1
- 16 of 21 men with chronic fissures experienced erectile dysfunction 1
- Anal pain radiated to the penis and worsened with erection and thrusting 1
- Electromyographic studies showed increased resting IAS activity (the hypertonic spasm), while BCM and EAS activity remained normal 1
Critically, when the fissures healed—30 of 32 acute cases and 19 of 21 chronic cases—the erectile dysfunction resolved completely. 1 The four patients whose ED persisted were the same four whose fissures failed to heal. 1
Will Fissure Treatment Abolish or Restore the Sensation?
The Evidence Strongly Suggests Restoration, Not Abolition
Treatment that successfully heals the fissure should restore—not eliminate—your patient's ability to experience pelvic-floor-driven arousal, because the therapeutic goal is to normalize IAS tone while preserving BCM-EAS function. 1, 2
Here's the mechanistic reasoning:
The problem is IAS hypertonia and pain, not BCM dysfunction—EMG studies confirm the BCM remains electrically normal during fissure-related ED. 1
Medical therapy (topical calcium channel blockers) reduces IAS tone without affecting the EAS or BCM. Compounded 0.3% nifedipine with 1.5% lidocaine blocks L-type calcium channels specifically in IAS smooth muscle, achieving 95% healing while leaving the voluntary striated muscle of the EAS-BCM complex intact. 2, 3
Lateral internal sphincterotomy (LIS) divides only the IAS, not the EAS or BCM. 2 The procedure targets the hypertonic smooth muscle responsible for pain and ischemia, while the striated muscle responsible for voluntary contraction and sexual function remains untouched. 2
The clinical outcome data confirm functional restoration: 30 of 32 men with acute fissures and 19 of 21 with chronic fissures regained normal erectile function after fissure treatment. 1 This demonstrates that eliminating IAS spasm allows the BCM to resume its role in sexual response.
Treatment Algorithm to Preserve Sexual Function
Step 1: First-Line Medical Therapy (6–8 Weeks)
Start with compounded 0.3% nifedipine + 1.5% lidocaine applied three times daily, combined with:
- Dietary fiber 25–30 g/day 2, 4
- Adequate hydration 2, 4
- Warm sitz baths 2–3 times daily to promote sphincter relaxation 2, 4
This regimen achieves 95% healing and should restore sexual function without any risk to the BCM-EAS complex. 2, 3
Step 2: Botulinum Toxin Injection (If Medical Therapy Fails)
If the fissure persists after 6–8 weeks, botulinum toxin injection into the IAS achieves 75–95% cure rates and is sphincter-sparing. 2 This temporarily paralyzes the hypertonic IAS smooth muscle while leaving the voluntary EAS-BCM intact. 2
Step 3: Lateral Internal Sphincterotomy (For Chronic Refractory Cases)
If both medical therapy and botulinum toxin fail, LIS is the gold standard with >95% healing and 1–3% recurrence. 2 The procedure divides only the IAS at the 3 or 9 o'clock position, preserving the EAS and BCM. 2
The risk of minor permanent incontinence (typically flatus) is 1–10%, far lower than the 10–30% risk with manual dilation, which is absolutely contraindicated. 2
Critical Pitfalls to Avoid
Never Perform Manual Anal Dilation
Manual dilation is absolutely contraindicated because it causes uncontrolled injury to both the IAS and EAS-BCM complex, resulting in 10–30% permanent incontinence. 2 This would directly damage the anatomical structures responsible for your patient's sexual sensation. 2
Do Not Assume All Treatments Lower Tone Equally
- Topical calcium channel blockers and botulinum toxin are IAS-selective and do not weaken the EAS or BCM. 2, 3
- LIS divides only the IAS, leaving the voluntary sphincter mechanism intact. 2
- Manual dilation injures both sphincters indiscriminately and should never be used. 2
Counsel the Patient on Expected Timeline
- Pain relief typically occurs after 14 days of topical therapy 3
- Full healing requires 6–8 weeks of consistent treatment 2, 3
- Sexual function should improve in parallel with fissure healing, as demonstrated in the clinical series where ED resolved when fissures healed 1
Explaining the Prognosis to Your Patient
Reassure him that the goal of fissure treatment is to eliminate the painful IAS spasm that is blocking his sexual response, not to weaken the pelvic floor muscles he voluntarily contracts for arousal. 1, 2
The evidence shows:
- His BCM and EAS are structurally and electrically normal—the problem is IAS hypertonia and pain 1
- Successful fissure treatment restored erectile function in 94% of acute cases and 90% of chronic cases 1
- Medical therapy and LIS target only the IAS, preserving the voluntary sphincter complex 2, 3
He should expect his ability to consciously engage his pelvic floor and experience wave-like arousal to return once the fissure heals and the pain-spasm cycle is broken. 1