Defecography
Defecography | |
---|---|
Caulking gun used for defecating proctogram | |
MeSH | D019841 |
Defecography (also known as proctography, defecating/defecation proctography, evacuating/evacuation proctography or dynamic rectal examination) is a type of medical
History
Defecating proctography was pioneered in 1945, during
It has fallen out of favor due to inadequate training in the technique. It is now only performed at a few institutions. Many radiology residents refer to the procedure as the "Def Proc", "Defogram", or "Stool Finale".[citation needed]
Indications
Defecography may be indicated for the following reasons:
- Evaluation of rectal outlet obstruction (obstructed defecation) symptoms
- Evaluation of all types of rectal (fecal) incontinence.
- Suspected conditions such as internal rectal intussusception, enterocele, anismus, rectocele or sigmoidocele.
- To compare pre- and post-surgical repair of rectal outlet obstruction (obstructed defecation).[2]
Specifically, defecography can differentiate between anterior and posterior rectocele.[4] Also, in external rectal prolapse that was not directly visualized during examination, this radiographic projection will demonstrate its presence.
Technique
In females, pre-procedural preparation involves smearing a small amount of barium contrast agent in the vagina, which will help to identify if anterior rectocele, enterocele or sigmoidocele is present.
The technique itself involves the insertion of a
Diagnostic yield and interpretation
Anatomical and physiological parameters that can be objectively measured by this investigation include:[2]
- Anorectal angle: This is the "mid-axial longitudinal axis of the rectum and the anal canal", created by the anterior pull of the puborectalis sling at the level of the anorectal junction. At rest, it is held at 90 - 100°. This becomes more acute (70 - 90°) when the patient contracts the anal sphincters and pelvic floor muscles, and more obtuse (110 - 180°)during defecation.
- ).
- Efficiency of emptying/evacuation: Normally, there is 90-100% evacuation of rectal contents.
- Anal canal length: This is measured during maximal evacuation.
- Anal canal width: Again measured during maximal evacuation, this is usually less than 2.5 cm.
Conditions which may be demonstrated include:[2]
- Anismus (pelvic floor dyssynergia): It has been suggested that some patients may be embarrassed by this procedure, which give findings of abnormal defecation.[2] For example, the patient may not be able to relax under the conditions, leading to relaxation failure of puborectalis and false positive diagnosis of anismus. It has also been reported that there is a high false positive rate of anismus diagnosis with anorectal manometry for similar reasons.[5]
- Rectocele: This is the most common finding with this type of imaging. Almost always, this is an anterior rectocele where the anterior rectal wall bulges forward, into the vagina in females. In males, the prostate gland gives more support in this area compared to the vaginal cavity, so rectoceles, especially anterior rectoceles are uncommon in males. Less commonly and in males, there may be posterior rectoceles, where the rectum bulges posteriorly. Both the size and the efficiency of emptying can be assessed with proctography. Since many rectoceles are asymptomatic, this may only be a significant finding if there are symptoms of obstructed defecation. Usually rectoceles greater than 3 cm and those that do not empty are clinically significant.
- Enterocele and sigmoidocele: Enterocele is a prolapse of peritoneum that contains a section of small intestine. Sigmoidocele is a prolapse of peritoneum that contains a section of sigmoid colon. In females, these prolapses usually descend between the rectum and the vagina. They are most likely to be seen during straining.
- Internal rectal intussusception:
The rectum may be seen to prolapse, whether internally or externally. There can be difficulty differentiating between internal intussusception and a normal rectal fold. The thickness of the intussusception is half the width of the intussusception (the intussusception is a doubled over layer of rectal wall). This is most likely to be seen during straining.
- Megarectum: This is excessive width (>9 cm) of the rectum at the level of the distal sacrum and incomplete evacuation.
- Descending perineum syndrome: If the perineum descends >4 cm, descending perineum syndrome may be diagnosed.
- Fecal incontinence: If the barium paste does not stay in the rectum.
Cinedefecography and MRI defecography
Cinedefecography is a technique that is an evolution of defecography. The defecation cycle is recorded as a continuous series rather than individual still radiographs.[2] More recent techniques involve the use of advanced, cross-sectional imaging modalities such as magnetic resonance imaging.[6] This is known as dynamic pelvic MRI, or MRI proctography.[2] The MRI proctography also called MRI defecography is not as efficient as conventional X-ray defecography for some problems.[citation needed]
See also
References
- ^ "Defecating proctogram from Bristol Laparoscopic Surgery". Archived from the original on 2016-03-04. Retrieved 2010-07-17.
- ^ ISBN 978-0-387-24846-2.)
{{cite book}}
:|first=
has generic name (help)CS1 maint: multiple names: authors list (link - ^ "ASCRS: Pelvic Floor Dysfunction". Archived from the original on 2015-02-10. Retrieved 2010-07-17.
- ^ Wiersma, Tjeerd. "Dynamic rectal examination on the Radiology assistant". Archived from the original on 13 October 2012. Retrieved 19 October 2012.
- PMID 9301508.
- ^ MRI Defecating Proctogram
External links
- Dynamic rectal examination on "the Radiology Assistant", many example defecating proctograms with interpretation.