Overview
Definition:
Pelvic floor dyssynergia (PFD), also known as anismus or functional defecatory disorder, is characterized by discoordination of the pelvic floor muscles during attempted defecation
This involves paradoxical contraction of the external anal sphincter and/or puborectalis muscle, along with inadequate relaxation of these muscles, leading to impaired expulsion of stool
It is a subtype of chronic constipation.
Epidemiology:
PFD is a common cause of chronic constipation, affecting a significant proportion of patients presenting with defecatory dysfunction
Prevalence estimates vary, but it is found in up to 50% of patients referred to tertiary defecation disorders clinics
It can affect both men and women, with some studies suggesting a slightly higher prevalence in women.
Clinical Significance:
Understanding the surgical interface of PFD is crucial for surgeons dealing with chronic constipation and defecatory dysfunction
Inadequate diagnosis and management can lead to persistent symptoms, reduced quality of life, and psychological distress
Surgical interventions are typically reserved for refractory cases after conservative management has failed, and require careful patient selection and procedural execution.
Clinical Presentation
Symptoms:
Feeling of incomplete evacuation
Straining during defecation
Need for manual maneuvers (e.g., digital evacuation, perineal pressure) to defecate
Frequent bowel movements with passage of small amounts of hard stool
Bloating and abdominal discomfort
Rectal pain or pressure
Sensation of anal blockage.
Signs:
Physical examination may reveal an hypertrophied or poorly relaxed external anal sphincter on digital rectal examination (DRE)
Rectal prolapse or intussusception may be present
Paradoxical contraction of the puborectalis muscle may be elicited during attempted defecation maneuvers.
Diagnostic Criteria:
Diagnosis is primarily based on clinical symptoms and confirmed by anorectal manometry, specifically demonstrating paradoxical contraction of the puborectalis or external anal sphincter during attempted defecation, or inadequate relaxation
Rome IV criteria for Functional Constipation or Obstructed Defecation Syndrome are often met.
Diagnostic Approach
History Taking:
Detailed history of bowel habits, including frequency, consistency, straining, sensation of incomplete evacuation, and need for manual maneuvers
Assess for red flags such as rectal bleeding, unintentional weight loss, family history of colorectal cancer, or change in stool caliber suggesting obstruction
Evaluate prior treatments and response.
Physical Examination:
General abdominal examination
Digital rectal examination (DRE) to assess sphincter tone, presence of stool, rectal masses, and assess for paradoxical contraction during attempted defecation
Perineal inspection for prolapse or scarring
Assessment for pelvic organ prolapse in women.
Investigations:
Anorectal manometry: Gold standard for diagnosing PFD, demonstrating inadequate relaxation or paradoxical contraction of pelvic floor muscles during defecation attempt
Balloon expulsion test: Assesses ability to expel a balloon, which may be impaired in PFD
Defecography or dynamic MRI: Can identify rectal intussusception, rectocele, or perineal descent, often co-existing with PFD
Colon transit study: To assess overall colonic motility and rule out slow transit constipation.
Differential Diagnosis:
Other causes of obstructed defecation: Rectal prolapse, rectocele, intussusception, anal stricture, fecal impaction
Irritable bowel syndrome with constipation (IBS-C)
Pudendal neuralgia
Hirschsprung's disease (in younger patients)
Slow transit constipation.
Management
Initial Management:
Biofeedback therapy: First-line treatment for PFD, aims to retrain pelvic floor muscle coordination by providing visual or auditory feedback
Dietary modifications: High-fiber diet and adequate fluid intake
Bowel training program: Regular toileting and establishing a defecation routine.
Medical Management:
Laxatives: Osmotic laxatives (e.g., polyethylene glycol) or stimulant laxatives may be used cautiously to facilitate bowel movements, but are not curative for PFD itself
Prokinetics are generally not effective for PFD.
Surgical Management:
Surgical intervention is reserved for severe, refractory cases of PFD unresponsive to comprehensive conservative management, especially when co-existing structural abnormalities are identified
Indications include severe symptoms, significant structural defects, and failure of biofeedback and medical therapy
Procedures may include rectocele repair, rectopexy (for rectal prolapse), STARR (stapled transanal rectal resection) procedure for obstructed defecation, or sacral neuromodulation
The surgical approach is individualized based on the specific anatomical derangement identified on defecography/MRI and manometry findings.
Supportive Care:
Psychological support: Addressing anxiety and depression associated with chronic constipation
Pelvic floor physiotherapy beyond biofeedback for core muscle strengthening and relaxation techniques.
Complications
Early Complications:
Postoperative pain
Bleeding
Infection
Urinary retention
Fecal incontinence (temporary or persistent).
Late Complications:
Recurrence of symptoms
Anal stricture
Persistent fecal incontinence
Development of rectovaginal or rectourethral fistula (rare)
Failure of surgery.
Prevention Strategies:
Careful patient selection for surgery
Meticulous surgical technique
Appropriate postoperative care and rehabilitation
Avoiding unnecessary surgical intervention.
Prognosis
Factors Affecting Prognosis:
Severity of PFD
Presence of co-existing structural abnormalities
Patient adherence to biofeedback and lifestyle modifications
Successful correction of anatomical defects
Surgeon's experience.
Outcomes:
Biofeedback therapy has a high success rate for PFD, often leading to significant symptom improvement
Surgical outcomes are variable and depend on the procedure performed and the underlying pathology
Success rates for STARR procedures and sacral neuromodulation vary but can provide relief in carefully selected patients
Long-term outcomes require ongoing management and lifestyle adjustments.
Follow Up:
Regular follow-up with a specialist is essential, particularly after surgical intervention
This includes monitoring bowel function, assessing for recurrence of symptoms, and managing any late complications
Continued participation in physiotherapy or bowel training programs may be beneficial.
Key Points
Exam Focus:
PFD is a motility disorder requiring diagnosis via manometry
Biofeedback is the cornerstone of non-surgical management
Surgery is reserved for refractory cases with identifiable structural defects, often involving procedures like STARR or rectopexy.
Clinical Pearls:
Always consider PFD in patients with chronic constipation and straining despite adequate fiber and fluid intake
Digital rectal examination during attempted defecation can be highly informative
Co-existing conditions like rectocele or prolapse often need to be addressed surgically alongside PFD management.
Common Mistakes:
Over-reliance on laxatives without addressing the underlying coordination issue
Performing surgery without adequate pre-operative workup and failed conservative trials
Inadequate biofeedback training leading to poor patient compliance
Misinterpreting manometry findings or overlooking structural abnormalities.