In a man with preserved continence, does reduced internal anal sphincter (IAS) or external anal sphincter (EAS) pressure affect his ability to achieve orgasm?

Reduced Anal Sphincter Pressure Does Not Directly Impair Orgasm in Men with Preserved Continence

In men with preserved continence, reduced internal anal sphincter (IAS) or external anal sphincter (EAS) pressure alone does not directly affect the ability to achieve orgasm. However, if sphincter dysfunction is severe enough to cause actual fecal incontinence or involves injury to the bulbocavernosus muscle complex, orgasmic and ejaculatory function may be impaired.

Key Physiological Distinctions

Sphincter Pressure and Continence Are Separate from Orgasmic Function

• The IAS maintains resting anal tone and is responsible for most passive continence, while the EAS provides voluntary squeeze pressure 1.
• Research demonstrates that men engaging in anoreceptive intercourse can have significantly reduced resting anal pressures (70.7 vs. 91.4 mm Hg) without any complaints of fecal incontinence or sexual dysfunction 2.
• Studies using topical anal anesthesia show that abolishing anal sensation and reducing voluntary squeeze amplitude does not impair continence in healthy volunteers, and some subjects actually retained more rectal volume when the anal canal was anesthetized 3.

The Critical Exception: Bulbocavernosus Muscle Injury

• If EAS injury extends to involve the bulbocavernosus muscle, erectile and ejaculatory dysfunction can occur 4.
• In 16 men with post-surgical anal sphincter injury, the bulbocavernosus reflex was absent, and they experienced erectile dysfunction with inability to maintain erection until ejaculation 4.
• The bulbocavernosus muscle contracts rhythmically during orgasm to raise cavernosal pressure above systolic blood pressure, enabling both sustained erection and forceful ejaculation in jets 4.
• Surgical repair of the external anal sphincter in these patients restored both fecal continence and normal erectile/ejaculatory function 4.

Clinical Algorithm for Assessment

When Sphincter Pressure Reduction Does NOT Affect Orgasm:

• Patient maintains fecal continence despite reduced IAS/EAS pressures 2
• No injury to the bulbocavernosus muscle or perineal nerve complex 4
• Erectile rigidity is adequate for penetration 5
• No concurrent medications impairing orgasm (antidepressants, antihypertensives) 5

When to Suspect Sphincter-Related Sexual Dysfunction:

• History of anorectal surgery (particularly anal fistula repair) with subsequent onset of both fecal incontinence AND erectile/ejaculatory problems 4
• Absent bulbocavernosus reflex on examination 4
• Ejaculation occurs without forceful jets or is absent entirely 4
• Inability to maintain erection through ejaculation despite adequate initial tumescence 4

Management Approach

For Isolated Sphincter Pressure Reduction with Preserved Continence:

• No specific intervention is required for the sphincter dysfunction itself, as it does not impair orgasmic function 3, 2.
• Assess for concurrent erectile dysfunction using standard ED evaluation and treatment protocols 5.
• Review medications that may impair orgasm independently of sphincter function 5.
• Consider psychosexual counseling if true anorgasmia is present, as psychological factors are often contributory 5.

For Sphincter Injury with Bulbocavernosus Involvement:

• Surgical repair of the external anal sphincter should be considered, as this can restore both continence and sexual function 4.
• Electromyography of the EAS and bulbocavernosus muscle can document the extent of injury 4.
• Measurement of anal and penile bulb pressures at rest and during voluntary squeeze provides objective assessment 4.

Important Clinical Caveats

• The mere presence of reduced sphincter pressures does not predict sexual dysfunction if continence is maintained 2.
• Anal sensation itself is not critical for preserving continence, and its loss does not explain incontinence after anorectal surgery 3.
• Pelvic autonomic nerve injury from anorectal surgery can cause bladder sensory loss and sexual arousal deficits through a completely separate mechanism from sphincter dysfunction 6.
• If sexual dysfunction persists beyond 6 months after pelvic surgery, irreversible autonomic nerve damage should be considered, requiring adaptation strategies rather than expectation of full restoration 6.