Rectal Anatomy After Rectopexy: Cinedefecography Versus MR-Defecography

Imaging modalities for the detection of posterior pelvic floor disorders in women with obstructed defaecation syndrome

BACKGROUND

Obstructed defaecation syndrome (ODS) is difficulty in evacuating stools, requiring straining efforts at defaecation, having the sensation of incomplete evacuation, or the need to manually assist defaecation. This is due to a physical blockage of the faecal stream during defaecation attempts, caused by rectocele, enterocele, intussusception, anismus or pelvic floor descent. Evacuation proctography (EP) is the most common imaging technique for diagnosis of posterior pelvic floor disorders. It has been regarded as the reference standard because of extensive experience, although it has been proven not to have perfect accuracy. Moreover, EP is invasive, embarrassing and uses ionising radiation. Alternative imaging techniques addressing these issues have been developed and assessed for their accuracy. Because of varying results, leading to a lack of consensus, a systematic review and meta-analysis of the literature are required.

OBJECTIVES

To determine the diagnostic test accuracy of EP, dynamic magnetic resonance imaging (MRI) and pelvic floor ultrasound for the detection of posterior pelvic floor disorders in women with ODS, using latent class analysis in the absence of a reference standard, and to assess whether MRI or ultrasound could replace EP. The secondary objective was to investigate differences in diagnostic test accuracy in relation to the use of rectal contrast, evacuation phase, patient position and cut-off values, which could influence test outcome.

SEARCH METHODS

We ran an electronic search on 18 December 2019 in the Cochrane Library, MEDLINE, Embase, SCI, CINAHL and CPCI. Reference list, Google scholar. We also searched WHO ICTRP and clinicaltrials.gov for eligible articles. Two review authors conducted title and abstract screening and full-text assessment, resolving disagreements with a third review author.

SELECTION CRITERIA

Diagnostic test accuracy and cohort studies were eligible for inclusion if they evaluated the test accuracy of EP, and MRI or pelvic floor ultrasound, or both, for the detection of posterior pelvic floor disorders in women with ODS. We excluded case-control studies. If studies partially met the inclusion criteria, we contacted the authors for additional information.

DATA COLLECTION AND ANALYSIS

Two review authors performed data extraction, including study characteristics, 'Risk-of-bias' assessment, sources of heterogeneity and test accuracy results. We excluded studies if test accuracy data could not be retrieved despite all efforts. We performed meta-analysis using Bayesian hierarchical latent class analysis. For the index test to qualify as a replacement test for EP, both sensitivity and specificity should be similar or higher than the historic reference standard (EP), and for a triage test either specificity or sensitivity should be similar or higher. We conducted heterogeneity analysis assessing the effect of different test conditions on test accuracy. We ran sensitivity analyses by excluding studies with high risk of bias, with concerns about applicability, or those published before 2010. We assessed the overall quality of evidence (QoE) according to GRADE.

MAIN RESULTS

Thirty-nine studies covering 2483 participants were included into the meta-analyses. We produced pooled estimates of sensitivity and specificity for all index tests for each target condition. Findings of the sensitivity analyses were consistent with the main analysis. Sensitivity of EP for diagnosis of rectocele was 98% (credible interval (CrI)94%-99%), enterocele 91%(CrI 83%-97%), intussusception 89%(CrI 79%-96%) and pelvic floor descent 98%(CrI 93%-100%); specificity for enterocele was 96%(CrI 93%-99%), intussusception 92%(CrI 86%-97%) and anismus 97%(CrI 94%-99%), all with high QoE. Moderate to low QoE showed a sensitivity for anismus of 80%(CrI 63%-94%), and specificity for rectocele of 78%(CrI 63%-90%) and pelvic floor descent 83%(CrI 59%-96%). Specificity of MRI for diagnosis of rectocele was 90% (CrI 79%-97%), enterocele 99% (CrI 96%-100%) and intussusception 97% (CrI 88%-100%), meeting the criteria for a triage test with high QoE. MRI did not meet the criteria to replace EP. Heterogeneity analysis showed that sensitivity of MRI performed with evacuation phase was higher than without for rectocele (94%, CrI 87%-98%) versus 65%, CrI 52% to 89%, and enterocele (87%, CrI 74%-95% versus 62%, CrI 51%-88%), and sensitivity of MRI without evacuation phase was significantly lower than EP. Specificity of transperineal ultrasound (TPUS) for diagnosis of rectocele was 89% (CrI 81%-96%), enterocele 98% (CrI 95%-100%) and intussusception 96% (CrI 91%-99%); sensitivity for anismus was 92% (CrI 72%-98%), meeting the criteria for a triage test with high QoE. TPUS did not meet the criteria to replace EP. Heterogeneity analysis showed that sensitivity of TPUS performed with rectal contrast was not significantly higher than without for rectocele(92%, CrI 69%-99% versus 81%, CrI 58%-95%), enterocele (90%, CrI 71%-99% versus 67%, CrI 51%-90%) and intussusception (90%, CrI 69%-98% versus 61%, CrI 51%-86%), and was lower than EP. Specificity of endovaginal ultrasound (EVUS) for diagnosis of rectocele was 76% (CrI 54%-93%), enterocele 97% (CrI 80%-99%) and intussusception 93% (CrI 72%-99%); sensitivity for anismus was 84% (CrI 59%-96%), meeting the criteria for a triage test with very low to moderate QoE. EVUS did not meet the criteria to replace EP. Specificity of dynamic anal endosonography (DAE) for diagnosis of rectocele was 88% (CrI 62%-99%), enterocele 97% (CrI 75%-100%) and intussusception 93% (CrI 65%-99%), meeting the criteria for a triage test with very low to moderate QoE. DAE did not meet the criteria to replace EP. Echodefaecography (EDF) had a sensitivity of 89% (CrI 65%-98%) and specificity of 92% (CrI 72%-99%) for intussusception, meeting the criteria to replace EP but with very low QoE. Specificity of EDF for diagnosis of rectocele was 89% (CrI 60%-99%) and for enterocele 97% (CrI 87%-100%); sensitivity for anismus was 87% (CrI 72%-96%), meeting the criteria for a triage test with low to very low QoE.

AUTHORS' CONCLUSIONS

In a population of women with symptoms of ODS, none of the imaging techniques met the criteria to replace EP. MRI and TPUS met the criteria of a triage test, as a positive test confirms diagnosis of rectocele, enterocele and intussusception, and a negative test rules out diagnosis of anismus. An evacuation phase increased sensitivity of MRI. Rectal contrast did not increase sensitivity of TPUS. QoE of EVUS, DAE and EDF was too low to draw conclusions. More well-designed studies are required to define their role in the diagnostic pathway of ODS.

The use of dynamic MR imaging in patients with clinical pelvic floor disorders

OBJECTIVES

To determine the differences and challenging aspects of dynamic magnetic resonance defecography (MRD) compared to conventional defecography (CD) in diagnostic of clinical symptomatic pelvic floor dysfunction.

METHODS

Fifty patients (44 females, 6 males; mean age: 57 years) with symptomatic pelvic floor dysfunction underwent both examinations, CD and MRD. Results were retrospectively intra-individual and interindividual evaluated in this multicentre study. Visibility and accuracy in diagnosis and classification of rectal prolapse, rectocele, enterocele, sigma diverticula and Cul-de-sac phenomenon/syndrome were observed. Differences were analysed using Mann-Whitney U test. P-values < 0.05 were considered as statistically significant.

RESULTS

CD was significantly superior to MRD in diagnosis and grading of rectal prolapse (p < .001), diagnosis and metric measurements of rectoceles (p = .016), diagnosis of elongated sigmoid colon (p = .008) and Cul-de-sac phenomenon and syndrome, respectively (p = .015; p = .008). MRD revealed equal results to CD in detection, localization, tendency to retention and enlargement of rectoceles (p = .337) and findings of enteroceles (p = .604) as well as sigma diverticula (p = .149).

CONCLUSIONS

The complementary use of both examination methods, CD and MRD, is important to achieve a comprehensive look on every aspect of pelvic floor disorders and gain optimal results in detection and evaluation of all major disorders of the pelvic floor.

Dynamic Magnetic Resonance Imaging and pelvic floor disorders: how and when?

Pelvic Floor Disorders (PFD) are a major public health problem in the world and decrease seriously the patient's quality of life. In case of recurrence after surgery or complex prolapse, imaging techniques can be used. Dynamic MRI, introduced in the early 1990s, offers information of the four compartments of the pelvis with a high resolution and a direct visualization of muscles and fascias in multiple planes. But for a practical use, such an expensive exam should be well correlated to symptoms and clinical examination or change surgical approach. The aim of our review was to precise the evidence regarding techniques, and indication of dynamic MRI in the assessment of pelvic floor disorders in daily practice. The first part is a review of available studies on methods of carrying out the dynamic MRI. The second part consists on the comparison of dynamic MRI to other assessment methods in case of pelvic floor disorders. Results emphasize the lack of strong level studies about the interest of dynamic MRI in the diagnosis and surgical management of pelvic organ prolapse. Although dynamic MRI appears highly reproducible between examiners, especially for the anterior compartment, its correlation with the degree of prolapse or the symptoms appears low. The most interesting field of application seems the detection of levator ani (LA) avulsion with a higher risk of prolapse and recidive in case of LA defects. More prospective, randomized, comparative studies have to be done.

Posterior pelvic floor disorders and obstructed defecation syndrome: clinical and therapeutic approach

There are no clear recommended imaging guidelines for the assessment of patients presenting primarily with obstructed defecation syndrome and defecation difficulty. The gold standard has always been the defecating proctogram which may require a rather poorly tolerated extended technique involving high-radiation exposure in young women which includes cystography, vaginography, small bowel opacification, and occasional peritoneography. The development of dynamic magnetic resonance imaging has obviated many of these extended techniques and may be supplemented by novel ultrasonographic methods including dynamic transperineal sonography, real-time 3D translabial ultrasound and 3D dynamic echodefecography. Patients potentially suitable for surgical treatment display a multiplicity of pelvic floor and perineal soft-tissue anomalies where one pathology (such as rectocele or enterocele) are considered dominant. Despite the introduction of recent stapled and robotic technologies, there is a dual dialog concerning the functional outcome of these procedures. Imaging and surgical algorithms for these patients are provided.

Evaluation and surgical treatment of rectal prolapse: an international survey

AIM

Validated guidelines for the surgical and non-surgical treatment of rectal prolapse (RP) do not exist. The aim of this international questionnaire survey was to provide an overview of the evaluation, follow-up and treatment of patients with an internal or external RP.

METHOD

A 36-question questionnaire in English about the evaluation, treatment and follow-up of patients with RP was distributed amongst surgeons attending the congresses of the European Association for Endoscopic Surgery and the European Society of Coloproctology in 2010. It was subsequently sent to all the members of the American Society of Colon and Rectal Surgeons and the European Society of Coloproctology by e-mail.

RESULTS

In all, 391 surgeons in 50 different countries completed the questionnaire. Evaluation, surgical treatment and follow-up of patients with RP differed considerably. For healthy patients with an external RP, laparoscopic ventral rectopexy was the most popular treatment in Europe, whereas laparoscopic resection rectopexy was favoured in North America. There was consensus only on frail and/or elderly patients with an external prolapse, with a preference for a perineal technique. After failure of conservative therapy, internal RP was mostly treated by laparoscopic resection rectopexy in North America. In Europe, laparoscopic ventral rectopexy and stapled transanal rectal resection were the most popular techniques for these patients.

CONCLUSION

The treatment of RP differs between surgeons, countries and regions. Guidelines are lacking. Prospective comparative studies are warranted that may result in universally accepted protocols.

[Anorectal diagnostics for proctological diseases]

The majority of proctological diseases can be defined by a structured evaluation of the symptoms and a physical examination. Magnetic resonance imaging (MRI) and anal endosonography can detect complex anal fistulas with a high accuracy but MRI should be preferred because of its objective visualization. Functional anorectal disorders are multifactorial and show morphological and functional irregularities in different compartments of the pelvic floor which is why MR defecography is now one of the most important methods in diagnostic algorithms. Interpreting the results of anal endosonography, anal manometry and neurophysiological testing is highly demanding because of large interindividual variability. Scores are used for objective measurement of symptom severity and quality of life. In clinical practice, well validated scores evaluated in large patient groups with predetermined circumstances are needed. Bringing together morphological results with scores based on subjective perception is required to optimize diagnostics and therapy evaluation in proctology.