In an adult post‑lateral sphincterotomy and trans‑sphincteric fistulotomy patient with low internal anal sphincter resting pressure, loss of pressure sensation but preserved continence, is external pelvic‑floor therapy as effective as internal pelvic‑floor therapy for restoring anorectal sensory feedback and sexual arousal?

External vs Internal Pelvic Floor Therapy After Sphincterotomy

For post-lateral sphincterotomy patients with low internal anal sphincter resting pressure and altered sensations but preserved continence, pelvic floor physical therapy must include both internal and external components—external therapy alone is insufficient to address the underlying myofascial dysfunction and neuropathic pain that drives these symptoms. 1, 2

Understanding the Post-Surgical Problem

The altered sensations and sexual dysfunction following lateral internal sphincterotomy represent primarily neuropathic pain and dysesthesia rather than structural sphincter damage. 2 This is a critical distinction because:

• Patients typically maintain intact continence despite experiencing altered pressure sensation and sexual arousal issues 1
• The problem stems from pelvic floor muscle tension and protective guarding patterns that developed during the painful fissure period and persist after surgery 1, 2
• These protective patterns affect both superficial (external) and deep (internal) pelvic floor musculature 3

Why Internal Therapy Is Essential

Internal pelvic floor work is mandatory because:

• The internal anal sphincter dysfunction and rectal sensory feedback impairment cannot be adequately addressed through external techniques alone 4
• Biofeedback therapy specifically targets rectal sensation, tolerance of rectal distention, and internal sphincter coordination—outcomes that require internal assessment and treatment 4
• Internal myofascial release directly addresses the hypertonic pelvic floor muscles adjacent to the surgical site 1, 2

Evidence-Based Treatment Protocol

The recommended approach includes 2-3 sessions weekly with the following components 1, 2:

Internal Components (Cannot Be Omitted)

• Internal myofascial release targeting hypertonic pelvic floor muscles 1, 2
• Rectal balloon training to restore anorectal sensory feedback and improve rectal distension tolerance 5
• Internal biofeedback using electronic devices to improve pelvic floor sensation and contraction 4

External Components (Necessary But Insufficient Alone)

• External myofascial release 1, 2
• Accessory muscle isolation and discrimination training 3
• Pelvic floor muscle strengthening and endurance training 3, 6

Adjunctive Measures

• Gradual desensitization exercises guided by a physical therapist 1, 2
• Topical lidocaine 5% ointment for neuropathic pain control 1, 2
• Warm sitz baths to promote muscle relaxation 1, 2

Supporting Evidence for Combined Approach

A randomized controlled trial of 80 patients with fecal incontinence demonstrated that rectal balloon training (internal therapy) added to pelvic floor muscle training produced superior outcomes in lifestyle quality of life scores, global perceived effect, maximum tolerable rectal volume, and external anal sphincter fatigue compared to external pelvic floor muscle training alone. 5 While this study addressed fecal incontinence rather than post-sphincterotomy dysfunction specifically, the physiologic principles of restoring anorectal sensory feedback are directly applicable.

The standardized pelvic muscle rehabilitation protocol emphasizes that diagnostic assessment must include internal evaluation (electromyography and manometry) to guide treatment selection, and therapeutic modalities must address both internal and external dysfunction. 3

Expected Timeline and Prognosis

• Dysesthesia and altered sensations typically improve significantly over 6-12 months with appropriate combined internal and external pelvic floor therapy 1
• Most patients show improvement, though the degree varies based on severity of initial dysfunction 5, 6

Critical Pitfalls to Avoid

• Never pursue additional surgical interventions for these symptoms, as surgery would likely worsen the neuropathic component rather than improve it 1, 2
• Do not attempt external-only therapy expecting equivalent results—the internal component is essential for restoring anorectal sensory feedback 4, 5
• Avoid manual anal dilatation entirely, as it carries a 30% temporary and 10% permanent incontinence rate 1, 2

Alternative Prevention Strategy

For future patients, botulinum toxin injection represents a safer alternative to lateral internal sphincterotomy, achieving 75-95% cure rates with no risk of permanent incontinence or sexual dysfunction. 1, 2 This should be considered after 8 weeks of failed topical therapy with calcium channel blockers. 2