What is the management approach for an adult female with a history of pelvic surgery or conditions affecting the pelvic floor who presents with fat dissection into the rectovaginal septum?

Fat Dissection into the Rectovaginal Septum

In an adult female with fat dissection into the rectovaginal septum (peritoneocele), the primary management approach is advanced imaging with MR defecography or dynamic cystocolpoproctography to fully characterize the defect and identify occult multicompartment pelvic floor dysfunction, followed by pelvic floor biofeedback therapy as first-line treatment, reserving surgical repair only for symptomatic patients who fail conservative management.

Initial Diagnostic Approach

Obtain advanced dynamic imaging to characterize the full extent of pelvic floor dysfunction:

• MR defecography with rectal contrast is the preferred imaging modality because it provides direct visualization of pelvic organs and floor muscles, allows assessment of pelvic fascia and postsurgical changes, and facilitates defecation to improve detection of prolapse compared to dynamic pelvic floor MRI without rectal contrast 1

• Dynamic cystocolpoproctography (fluoroscopic CCP) is an alternative that shows good agreement with surgical findings for detection of peritoneocele, rectocele, and full-thickness rectal prolapse 2

• Critical pitfall to avoid: Physical examination alone is limited in depicting multicompartment involvement—92% of patients with posterior compartment defects have associated pelvic floor disorders in other compartments 3. Imaging prevents missing occult defects that would otherwise require reoperation 1

Understanding the Pathophysiology

Fat dissection into the rectovaginal septum represents a peritoneocele:

• This occurs when peritoneal fat from the posterior cul-de-sac herniates into the rectovaginal space 1, 2

• The underlying mechanism involves chronic straining during defecation and conditions causing chronic increases in intra-abdominal pressure, leading to weakening of pelvic floor support structures 4

• Direct or denervation injury to pelvic floor musculature increases stress on the fascia and leads to progressive weakening 4

First-Line Conservative Management

Initiate pelvic floor biofeedback therapy before considering surgical intervention:

• Structural abnormalities like peritoneoceles may at least partly result from excessive straining and/or pelvic floor dysfunction, making them primarily manageable with pelvic floor biofeedback therapy 1

• In a randomized trial of patients with rectal intussusception or rectocele, 33% of biofeedback patients reported greater than 50% reduction in obstructed defecation scores, with improvement in constipation-related quality of life 1

• Address underlying risk factors: Advanced age, menopause, vaginal multiparity, obesity, chronic straining, and conditions causing chronic increases in intra-abdominal pressure 4

Surgical Intervention Criteria

Reserve surgery only for patients with disabling symptoms who fail conservative management:

• Surgical options include transvaginal mesh repair of the rectovaginal septum with polypropylene mesh sutured to lateral bundles of the puborectal muscle 3

• Critical selection criteria: Surgery should only be considered for clinically significant defects (large defects that fill preferentially and/or fail to empty on defecating proctogram) and symptomatic patients (those requiring vaginal stenting during defecation) 1

• Important caveat: The correlation between symptoms and anatomic abnormalities is weak—symptoms may improve despite modest effects on anatomy and vice versa 1. Anatomic abnormalities are often caused by the underlying functional disorder (impaired pelvic floor relaxation and excessive straining), which surgery does not correct 1

Surgical Approach When Indicated

If surgery is pursued after failed conservative management:

• Transvaginal perineoplasty with polypropylene mesh placement in the rectovaginal septum, with complete dissection of the rectovaginal space and lateral suturing to puborectal muscle bundles, provides excellent anatomical results 3

• In one series of 77 patients, this approach resulted in only 1.2% rectocele recurrence and 2.6% mesh complications requiring partial extirpation 3

• Surgical pitfall: Patients should be counseled that advancement flap surgery carries risk of worsening symptoms in those in whom the operation fails, and some women may choose to accept residual symptoms over surgical complications to optimize overall quality of life 1

Special Considerations

Rule out serious underlying pathology before attributing symptoms to benign pelvic floor dysfunction:

• While rare, malignant transformation can occur in the rectovaginal septum, including endometrioid adenocarcinoma or gastrointestinal stromal tumors 5, 6

• Red flags requiring further investigation: Atypical presentation, lateral or multiple lesions, vaginal bleeding, or tissue alterations at vaginal or rectal openings 7, 8