What is the diagnosis and treatment of a rectocele (rectal prolapse) identified on a computed tomography (CT) scan?

Rectocele on CT Scan: Diagnosis and Management

CT scan is not an appropriate imaging modality for diagnosing or evaluating rectocele; if a rectocele is incidentally noted on CT, proceed directly to clinical examination followed by either MR defecography or fluoroscopic cystocolpoproctography (CCP) for proper assessment. 1

Why CT is Inadequate

• CT has no established role in rectocele evaluation - the American College of Radiology states there is no relevant literature supporting CT use (with or without IV contrast) for assessment of pelvic organ prolapse or functional defecatory dysfunction 1
• CT cannot perform dynamic/functional assessment during defecation, which is essential for rectocele diagnosis 1, 2
• While CT may incidentally show large levator muscle defects or masses causing obstruction, it cannot evaluate the severity, functional impact, or associated pelvic floor abnormalities that guide treatment 1

Proper Diagnostic Pathway After CT Finding

Step 1: Clinical Examination

• Perform digital rectal examination in left lateral decubitus position with buttocks separated 2
• Observe for perineal descent during simulated defecation and assess for posterior vaginal wall bulging 2
• Evaluate resting sphincter tone, puborectalis contraction during squeeze, and expulsionary forces when patient attempts to "expel my finger" 2
• Critical caveat: Normal physical examination does not exclude rectocele - physical exam detects only 7% of rectoceles compared to imaging 2

Step 2: Definitive Imaging (Choose One)

MR Defecography with Rectal Contrast (Preferred for comprehensive evaluation):

• One of the initial imaging tests of choice with high soft-tissue contrast resolution 1, 2
• Detects clinically occult abnormalities beyond clinical diagnosis in 34% of cases 1, 2
• Must include dynamic/defecation phase - static imaging is inadequate 1, 2
• Superior for detecting multi-compartment defects (enteroceles, sigmoidoceles, cystoceles) that coexist in many patients 1, 3
• Moderate to good correlation with surgical findings 2

Fluoroscopic CCP (Alternative, particularly for isolated posterior compartment):

• One of the initial imaging tests of choice, especially for posterior compartment prolapse 1, 2
• 94% sensitivity for rectocele detection compared to physical examination 1, 2
• Good agreement with surgical findings for rectocele, with 88% sensitivity for internal rectal prolapse 1
• Performed with patient in physiologic upright sitting position on fluoroscopic commode during rest, strain, and defecation 1
• Detects clinically occult rectoceles and enteroceles that physical examination misses 1, 2

Clinical Context and Associated Findings

• Rectoceles typically present with obstructive defecation symptoms: incomplete evacuation, straining, sensation of vaginal bulging, pelvic heaviness, and constipation 2
• 30-50% prevalence in women over age 50 4
• Frequently coexists with other pelvic floor defects - approximately one-third of patients with posterior vaginal wall bulging have enteroceles or sigmoidoceles 1
• Internal rectal prolapse may simulate rectocele or enterocele clinically 5

Treatment Considerations After Proper Diagnosis

Conservative management first - surgery only after failure of medical treatment and based on symptom intensity and quality of life deterioration 4

Surgical approach depends on rectocele characteristics 4:

• Low/mid rectum or isolated rectocele: Approach from below (transanal, transperineal, or transvaginal) 4, 6
• High rectocele or multi-compartment prolapse: Transabdominal rectopexy more suitable 4, 5

Recent comparative data (2021):

• Laparoscopic ventral mesh rectopexy (LVMR) shows better functional outcomes, anatomic correction, and quality of life compared to transvaginal posterior colporrhaphy 7
• LVMR associated with greater improvement in constipation scores (Cleveland Clinic Constipation Score: 6 vs 9.2 at 1 year) and sexual function (PISQ-12: 39.3 vs 35.8) 7
• Comparable complication rates between approaches, though LVMR has longer operative time 7

Key Clinical Pitfalls

• Never rely on CT findings alone - proceed to appropriate dynamic imaging 1
• Don't assume isolated rectocele - imaging frequently reveals multi-compartment defects that alter surgical planning 1, 3
• Ensure imaging includes defecation phase - significant proportion of enteroceles only visible upon complete rectal emptying or postdefecation strain 1
• Consider rectal prolapse in differential - internal prolapse may simulate rectocele and requires defecography to distinguish 5