Can pelvic‑floor (Kegel) training increase baseline resting anal sphincter pressure in a male patient after fistulotomy that removed the internal anal sphincter?

Can Kegel Exercises Raise Baseline Resting Anal Sphincter Pressure After Fistulotomy?

No, Kegel exercises cannot directly increase baseline resting anal sphincter pressure in a male patient after fistulotomy that removed the internal anal sphincter, because resting pressure is generated exclusively by the internal anal sphincter (IAS), which is smooth muscle under autonomic control and cannot be voluntarily strengthened. 1, 2

Understanding the Anatomy and Physiology

The internal anal sphincter contributes approximately 15–20% of resting anal pressure and is the sole determinant of baseline resting tone. 1 This smooth muscle operates under autonomic control and cannot be influenced by voluntary exercises. 2

Kegel exercises target only the external anal sphincter (EAS) and puborectalis muscle, which are skeletal muscles innervated by the pudendal nerve (S2–S4). 2, 3 These muscles contribute to voluntary squeeze pressure, not resting tone. 1

What Happens After IAS Removal

When the IAS is surgically removed or damaged during fistulotomy:

• The EAS and puborectalis develop compensatory hypertonicity to preserve continence, attempting to compensate for lost resting pressure. 2
• This compensation manifests as paradoxically increased squeeze pressure on manometry despite low resting tone. 2, 3
• Division of the IAS leads to incontinence in approximately 31% of patients, primarily urge and gas incontinence. 4

The Role of Kegel Exercises in This Context

Kegel exercises after IAS division serve a completely different purpose than raising resting pressure—they reduce compensatory hypertonicity and improve functional continence through neuromuscular retraining. 2, 4

Evidence for Kegel Exercises Post-Fistulotomy

In a 2022 study of 102 patients who underwent partial IAS division during fistula surgery, regular Kegel exercises (50 repetitions daily for 1 year) significantly reduced incontinence scores from 1.19 ± 1.96 to 0.26 ± 0.77 (P = 0.00001). 4 The exercises did not restore resting pressure but improved functional continence by:

• Training the EAS to provide more effective voluntary augmentation during urgency 4
• Reducing maladaptive compensatory hypertonicity that interferes with normal defecation 2
• Improving coordination between abdominal and pelvic floor muscles 2

Recommended Management Algorithm

Step 1: Diagnostic Evaluation

• Perform anorectal manometry to quantify IAS resting pressure (expected to be low), EAS squeeze augmentation (may be paradoxically high), and detect dyssynergic patterns. 2, 3
• Conduct digital rectal examination to assess resting tone and identify localized puborectalis tenderness indicating compensatory hypertonicity. 2, 3

Step 2: Conservative Therapy (First-Line, 6–12 Months)

• Initiate pelvic floor biofeedback therapy 2–3 times weekly, which achieves symptom improvement in >70% of patients with compensatory hypertonicity. 2, 5 Biofeedback uses real-time EMG feedback to teach muscle isolation, relaxation timing, and coordination. 2, 5
• Prescribe Kegel exercises 50 times daily, starting 10 days postoperatively and continuing for 1 year. 4 These exercises strengthen voluntary squeeze capacity without affecting resting tone. 4
• Add fiber supplementation (25–30 g daily) with adequate fluid intake to optimize stool consistency and reduce straining. 2, 3
• Recommend warm sitz baths to promote muscle relaxation. 2

Step 3: Adjunctive Symptom Management

• Apply topical lidocaine 5% ointment for perianal neuropathic dysesthesia. 2

Step 4: Advanced Interventions (If Conservative Therapy Fails)

• Consider dextranomer microspheres in hyaluronic acid (NASHA Dx), the only FDA-approved bulking agent for fecal incontinence, which achieves ≥50% reduction in incontinence episodes in 52% of patients at 6 months. 2, 3
• Refer for sacral nerve stimulation (SNS) targeting S2–S4 roots for patients who fail conservative therapy and bulking agents. 2, 3

Critical Contraindications

• Never perform manual anal dilatation—it causes permanent incontinence in 10–30% of patients. 2, 3
• Surgical revision of the sphincter complex is contraindicated for compensatory hypertonicity because the problem is neuromuscular, not mechanical. 2

Prognostic Factors

Significant improvement in pelvic floor function typically requires 6–12 months of consistent conservative therapy, with neuroplasticity continuing for 12–24 months. 2 However:

• Patients with baseline squeeze pressure <80 mmHg on manometry have poor prognosis—only 4 of 24 such patients achieved satisfactory continence improvement with biofeedback. 6
• Co-existing neurological disorders (diabetes, Parkinson's disease) limit retraining success due to secondary visceral neuropathy. 2, 3
• Prior intersphincteric dissection may have damaged inferior rectal branches of the pudendal nerve, potentially rendering compensatory patterns partially irreversible. 2, 3

Common Pitfalls to Avoid

• Do not expect Kegel exercises to restore resting pressure—this is physiologically impossible when the IAS is absent. 1, 2
• Do not rush to surgical intervention—all patients must receive an optimal trial of conservative therapy first. 3
• Do not assume normal digital rectal examination rules out pelvic floor dysfunction—objective testing with manometry is warranted when clinical suspicion persists. 3