What are the methods to diagnose a rectocele?

Diagnosis of Rectocele

Rectocele diagnosis begins with a thorough digital rectal examination in the left lateral position, specifically observing perineal descent during simulated defecation and assessing for posterior vaginal wall bulging, though imaging with MR defecography or cystocolpoproctography (CCP) is essential for definitive diagnosis and surgical planning, as physical examination alone detects only 7% of rectoceles identified on imaging. 1

Clinical Examination

Physical examination should include:

• Patient positioning in left lateral decubitus with buttocks separated to observe perineal descent during simulated evacuation and elevation during squeeze maneuvers 1

• Digital rectal examination evaluating:

  • Resting sphincter tone and augmentation with squeezing
  • Puborectalis muscle contraction during squeeze
  • Patient instructed to "expel my finger" to assess expulsionary forces 1
  • Palpation for posterior vaginal wall bulging suggestive of rectocele 1

• Important caveat: A normal digital rectal examination does not exclude rectocele or other defecatory disorders 1. Physical examination detects only 7% of rectoceles compared to CCP, making imaging critical for accurate diagnosis 1

Imaging Modalities (Essential for Definitive Diagnosis)

MR Defecography (Preferred Initial Imaging)

MR defecography with rectal contrast is one of the initial imaging tests of choice for suspected rectocele 1

• Advantages:

  • High soft-tissue contrast resolution allows direct visualization of pelvic organs, pelvic floor muscles, fascia, and anatomic abnormalities 1
  • Detects clinically occult abnormalities in 34% of cases beyond clinical diagnosis 1
  • Moderate to good correlation with surgical findings for rectocele detection 1
  • Detects 45% of enteroceles seen on physical examination, while physical examination only demonstrates 30% of enteroceles seen on MR defecography 1

• Technical requirements:

  • Must use rectal contrast and imaging during defecation phase 1
  • Patients should perform repeated strain/defecation maneuvers to maximize detection 1
  • Upright positioning preferred but most centers use supine positioning (may underestimate rectocele size) 1

Cystocolpoproctography (CCP) - Fluoroscopic Defecography

CCP is one of the imaging tests of choice, particularly for posterior compartment prolapse 1

• Diagnostic performance:

  • Sensitivity of 94% for rectocele detection compared to physical examination 1
  • Good agreement with surgical findings for rectocele detection 1
  • Detects clinically occult rectoceles that physical examination misses 1

• Advantages:

  • Functional evaluation in physiologic upright seated position 1
  • Assesses barium contrast retention within rectoceles, distinguishing clinically relevant from incidental findings 1
  • Sensitivity of 83% for peritoneocele detection 2

• Limitations:

  • Lacks soft-tissue contrast resolution 1
  • Cannot directly visualize pelvic floor muscles and fascia 1
  • Requires contrast installation in bladder, vagina, and oral contrast administration 1

Diagnostic Algorithm

1. Begin with detailed digital rectal examination in left lateral position with simulated defecation maneuvers 1

2. If rectocele suspected clinically OR patient has obstructive defecation symptoms, proceed to imaging regardless of examination findings, as physical examination alone is inadequate 1

3. Choose imaging modality:

   • MR defecography if available and if comprehensive pelvic floor evaluation needed or suspicion of multiple compartment defects 1
   • CCP for focused posterior compartment evaluation, particularly if MRI unavailable or contraindicated 1

4. Imaging must include dynamic/defecation phase to adequately assess rectocele 1

Clinical Presentation Supporting Diagnosis

Patients typically present with 3, 4:

• Obstructive defecation symptoms
• Need for digital vaginal splinting or disimpaction to effectuate bowel movement
• Sensation of vaginal bulging or pelvic heaviness
• Incomplete evacuation
• Constipation requiring straining

Critical pitfall: Rectoceles are common (30-50% prevalence in women over 50) but not all are symptomatic 3. Correlation between imaging findings and symptoms is essential before considering surgical intervention 3, 5.