What is the recommended evaluation and management for an adult with chronic reduced bladder‑filling sensation, now more apparent after recent fistulotomy, who voids completely with a normal post‑void residual and no neurologic red‑flags?

Management of Chronic Reduced Bladder-Filling Sensation After Fistulotomy with Complete Voiding

In an adult with chronic reduced bladder-filling sensation that became more apparent after fistulotomy but who voids completely with normal post-void residual, reassurance and conservative monitoring are appropriate—this represents a sensory abnormality without functional impairment that does not require intervention.

Understanding the Clinical Picture

Your patient presents with an unusual constellation of findings that requires careful interpretation:

• Complete bladder emptying with normal PVR indicates preserved detrusor function 1, 2. The ability to void completely argues strongly against significant bladder dysfunction requiring treatment.

• Reduced bladder-filling sensation without elevated PVR suggests a sensory rather than motor problem 1. This is fundamentally different from neurogenic bladder dysfunction, which typically presents with both sensory and motor abnormalities 1.

• The temporal relationship to fistulotomy is likely coincidental rather than causative 3. Anal fistulotomy affects the anal sphincter complex and pelvic floor, but direct injury to bladder innervation from this procedure is anatomically implausible. The surgery more likely heightened the patient's awareness of pre-existing subtle sensory changes 3.

Initial Assessment and Risk Stratification

Following the AUA/SUFU neurogenic bladder guidelines, even though this patient doesn't have classic neurogenic dysfunction, the framework is useful 1:

• Confirm normal voiding function with repeat PVR measurements 1, 2. Due to marked intra-individual variability, obtain 2-3 measurements on separate occasions to establish reliability 2.

• Document complete medical and neurologic history 1. Specifically inquire about:

  • Diabetes with peripheral neuropathy
  • Prior pelvic surgery or radiation
  • Spinal cord pathology or disc disease
  • Multiple sclerosis or other demyelinating conditions
  • Medications affecting bladder sensation (anticholinergics, opioids, alpha-agonists)

• Perform focused neurologic examination 1. Test perineal sensation, lower extremity reflexes, and rectal tone to exclude occult neurologic disease.

When Urodynamic Studies Are NOT Indicated

In this specific clinical scenario, urodynamic testing is not warranted 1. The AUA urodynamics guideline is clear that urodynamic studies are performed to reproduce symptoms and determine their cause when symptoms suggest dysfunction 1. Your patient has:

• Normal bladder emptying (complete voiding, normal PVR) 1, 2
• No storage symptoms (urgency, frequency, incontinence)
• No obstructive symptoms (hesitancy, weak stream, straining)
• No upper tract risk factors 1

Urodynamics would only be indicated if 1:

• PVR becomes elevated (>200-300 mL) on repeat measurements 2
• New storage or voiding symptoms develop
• Recurrent urinary tract infections occur 4
• Neurologic examination reveals abnormalities 1

Conservative Management Strategy

Implement a monitoring protocol rather than active intervention 1, 2:

• Schedule follow-up at 3-6 month intervals initially 1. Assess for:

  • Development of elevated PVR (repeat measurement at each visit) 1, 2
  • New lower urinary tract symptoms 1
  • Urinary tract infections 1
  • Changes in neurologic status 1

• Educate the patient on timed voiding 1. Since bladder-filling sensation is reduced, recommend voiding every 3-4 hours by the clock rather than waiting for urgency 2. This prevents bladder overdistension even without normal sensory cues.

• Teach double-voiding technique 2, 5. Have the patient void, wait 2-3 minutes, then attempt to void again—particularly useful given the sensory deficit 5.

• Maintain adequate hydration 2. Paradoxically, concentrated urine can irritate the bladder and worsen any subtle dysfunction.

Critical Pitfalls to Avoid

Do not initiate antimuscarinic medications 2. These agents would worsen any potential emptying issues and are contraindicated in patients with sensory deficits who may not perceive retention 2.

Do not assume this represents neurogenic bladder requiring aggressive management 1. The patient lacks the hallmarks of true neurogenic dysfunction: elevated PVR, detrusor overactivity, or upper tract changes 1.

Do not attribute all symptoms to the recent fistulotomy 3. While pelvic floor surgery can affect voiding, the chronic nature of these sensory changes suggests they preceded the procedure 3. The surgery likely made pre-existing subtle deficits more noticeable.

Do not delay evaluation if PVR becomes elevated 1, 2. A single PVR >200 mL should be confirmed with repeat measurement, but persistently elevated values (>200-300 mL) warrant urodynamic evaluation to distinguish obstruction from detrusor underactivity 2.

When to Escalate Care

Refer to urology if any of the following develop 1:

• Persistently elevated PVR (>200-300 mL on multiple measurements) 2
• Recurrent urinary tract infections (≥2 in 6 months) 1, 4
• New neurologic symptoms or examination findings 1
• Development of hydronephrosis on imaging 1
• Worsening or new lower urinary tract symptoms 1

Long-Term Prognosis

Patients with isolated sensory deficits and preserved motor function typically remain stable 1. The key is vigilant monitoring to detect any progression to functional impairment early, when intervention is most effective 1. The normal PVR is highly reassuring and suggests this will remain a sensory curiosity rather than a clinically significant problem 2, 6.