Post-Anorectal Surgery Sexual and Urinary Dysfunction
Most Likely Diagnosis
This patient most likely has iatrogenic pelvic autonomic nerve injury from the lateral sphincterotomy and/or fistulotomy procedures, causing denervation of deep pelvic structures responsible for sexual arousal and bladder sensation. The normal pudendal nerve pin-prick test excludes pudendal neuralgia but does not assess the autonomic pelvic nerve branches that mediate deep pelvic sensation, sexual arousal, and bladder fullness awareness 1.
Understanding the Neuroanatomy
The key to understanding this presentation is recognizing two distinct nerve systems:
- Pudendal nerve (somatic): Provides superficial perineal sensation and external sphincter control—this was tested and found normal 1
- Pelvic nerve (autonomic): Provides deep pelvic sensation, bladder detrusor sensation, and sexual arousal mechanisms—this was likely injured and was NOT tested 1
The pelvic nerve travels inferolateral to the rectum within the endopelvic fascial sleeve and sends branches to the bladder detrusor and urinary sphincter at the level of the prostatic apex (or bladder neck in females) 1. During lateral sphincterotomy and particularly during fistulotomy with revision for granulation tissue, these autonomic nerve branches are vulnerable to injury 1, 2.
Clinical Evidence Supporting Nerve Injury
The temporal relationship strongly supports iatrogenic nerve damage:
- Initial blunted sexual arousal after sphincterotomy (3 years ago) suggests partial autonomic nerve injury 2
- Worsening after fistulotomy with revision (7 months ago) indicates progressive or additional nerve damage 2
- New urinary blunting suggests injury to bladder sensory branches of the pelvic nerve 1, 2
Studies of deep pelvic surgery show that 10% of patients have persistent bladder dysfunction beyond 6 months, indicating irreversible nerve damage, while 90% recover within 6 months 2. At 7 months post-revision, this patient falls into the concerning category of likely permanent injury.
Specific Diagnostic Workup Required
Obtain the following assessments to confirm autonomic nerve dysfunction:
- Urodynamic testing with cystometry: Assess bladder sensation thresholds (first sensation, first desire to void, strong desire to void) and detrusor compliance to document sensory denervation 3
- Post-void residual measurement: Rule out detrusor denervation causing retention 1, 2
- Detailed sexual function questionnaire: Use standardized tools like the Female Sexual Function Index or Brief Index of Sexual Functioning to document specific domains (desire, arousal, lubrication, orgasm) 3
- Lumbosacral MRI: Rule out cauda equina syndrome or Tarlov cysts, which can present with similar symptoms of impaired perineal sensation and bladder/sexual dysfunction 3, 4
The absence of pain does NOT exclude nerve injury—denervation typically causes sensory loss rather than pain 3.
Management Algorithm
Immediate Actions (Now)
Refer to urogynecology or urology for formal urodynamic testing to document the extent of bladder sensory denervation 3
Obtain lumbosacral MRI to exclude central causes (cauda equina syndrome, Tarlov cysts) that could be surgically correctable 3, 4
Refer to pelvic floor physical therapy specializing in pelvic nerve dysfunction—this can address pelvic floor muscle dysfunction that may be contributing to symptoms 3
If Peripheral Nerve Injury Confirmed (Most Likely)
The prognosis for recovery is poor given the 7-month timeframe since the last surgery 2. However, pursue the following:
Pelvic floor physical therapy: Can improve pelvic floor muscle coordination and may partially compensate for sensory deficits 3
Sex therapy and psychosexual counseling: Essential to help adapt to altered sexual response patterns and explore alternative arousal mechanisms 3, 5
Consider referral to peripheral nerve specialist: If MRI shows nerve entrapment (unlikely in this case but possible), surgical decompression may be curative 4
Bladder retraining program: Timed voiding every 2-3 hours to compensate for reduced sensation of bladder fullness 3
Medications to Consider
For bladder sensory loss: No medications restore sensation, but timed voiding prevents overflow 3
For sexual arousal dysfunction: No FDA-approved medications exist for female sexual arousal disorder related to nerve injury 3
Topical estrogen (if postmenopausal): May improve vaginal tissue health and indirect arousal mechanisms, though it will not restore nerve function 3
Critical Pitfalls to Avoid
Do not assume this is psychological or will resolve with time—the 7-month timeframe and progressive worsening indicate structural nerve injury 2. The patient correctly identified reliance on a "deep pelvic pressure anchor point" for arousal, which represents autonomic nerve-mediated sensation that has been disrupted 1, 4.
Do not repeat pudendal nerve testing—it was already normal and tests the wrong nerve system 1. The pelvic autonomic nerves cannot be assessed with simple pin-prick testing 1.
Do not delay urodynamic testing—bladder sensory denervation can lead to chronic overdistension and permanent detrusor damage if not managed with timed voiding 3, 2.
Long-Term Expectations
Based on pelvic surgery literature, patients with persistent bladder and sexual dysfunction beyond 6 months post-surgery typically have irreversible nerve damage 2. The focus should shift from expecting full recovery to maximizing adaptation and quality of life through:
- Compensatory strategies (timed voiding, alternative sexual techniques) 3
- Psychological support for adjustment to altered function 3, 5
- Ongoing pelvic floor physical therapy 3
The patient should be counseled that complete restoration of the previous "deep pelvic anchor point" sensation is unlikely, but meaningful improvement in overall sexual satisfaction and bladder management is achievable with comprehensive rehabilitation 3, 2.