Defecating Proctogram: Pooping the poo and holding the fart studyDr Srividya Arya, Dr Jugal N Patel, Dr Suzanne Ryan

Learning objectives

• Be able to describe the appearances of a normal

resting anorectal anatomy as seen on fluoroscopic

defecating proctogrm study.

• Be able to describe the normal change in anatomy and

the physiological process of defecation.

• Be able to recognize the common abnormalities seen

on a defecating proctograms, in particular enterocele,

rectocele, rectal mucosal prolapse and paradoxical

puborectalis.

• Develop an understanding of what important positive

and negative findings should be reported back to the

referring clinician.

Common indications

• Constipation/obstructed defecation

• faecal incontinence

• suspected pelvic floor weakness

Contraindications

• Pregnancye

Equipment

Figure 1: Equipment; 1x EzPaque, 2xEzHD, 3x60mls syringe,1x10mls syringe. Gastrografin for female patients.

Set up of screening room

Preparation

Need for oral contrast:

Males- not required.

Females- required to opacify small bowel, to demonstrate any enteroceles which are common in females. 10ml Gastrografinand 100ml EzHD can be mixed in 200ml water and given to the patient to drink 1hr before the examination.

Preparing the rectal contrast:

45ml warm water is mixed with a pot of EzHD (or 35ml water per sachet) to give a tooth paste consistency. Contrast is administered prior to transferring the patient to the proctrogram chair.

Instructions to the patient

“Squeeze as though you are trying to hold a fart at a wedding”

“Now just poop it out”

Proctography requires images to be obtained at rest and whist the patient is squeezing and defecating. This can be very embarrassing for patients. Using simple everyday language can help the patient feel more ease.

Normal defecating mechanism

At rest the anal canal is closed with an anal rectal angle <100° made by puborectalis. The pelvic floor is above the ischial tuberosity.

During pelvic contraction, the rectum is elevated and the anal canal lengthens.

During Expulsion, there is pelvic floor descent and wideningOf the anal rectal angle.

Mild-to-moderate rectal descent. There is an anterior rectocele with a small amount of barium trapping (arrow). There is an Oxford grade 1 retorectal intussusception (*).

Patient is unable to empty completely (anismus), with ineffective evacuatoryeffort. Patient had a history of defunctioned bowel.

A low rectal intussusception to the level of the anal verge (arrow)

Significant small bowel enterocoelepresent (arrows).

Rectal Prolapse

Rectal prolapse may be internal (also known as intussusception) or external, where the bowel descends outside of the anus [3].

Risk factors:• Age,• Childbirth, • Constipation and straining. • Can be associated with prolapse of other pelvic organs• Patients may have a predisposition because of collagen

abnormalities.

Symptoms:• Obstructed defaecation syndrome (discomfort, pain,

constipation, difficult evacuation)• faecal incontinence with discharge of blood/mucus.• Rectocele (vaginal bulge) in women• Painful intercourse, • Lower back pain, • Urinary dysfunction, • Vaginal prolapse• enterocele.

Figure 3: Normal evacuation proctogram: Images during defecation [1]. At rest (a), the posterior anorectal angle (dotted white line) measures 100°; the level of the anorectal junction (ARJ) is marked by the solid black line; and the site of the closed anal canal (AC) is represented by the white arrow. During expulsion (b), the anorectal angle opens to 178°, the anorectal junction descends, and the anal canal opens

Figure 4: Defecating proctogram [1] (mechanics of a patient’s defecation are visualized in real time using a fluoroscope)

Figure 5: Oxford classification of intussusception [2] a) Normalb) Grade 1; recto-rectal intussusception (high rectal)c) Grade 2; Grade 1; recto-rectal intussusception (low rectal)d) Grade 3; recto-anal intussusception (high anal)e) Grade 4; recto-anal intussusception (low anal)f) Grade 5; external rectal prolapse.

a

d

cb

fe

Example cases

Mild rectal descent on squeezing and an anterior rectocele with a small amount of barium trapping. There is an Oxford grade 1 (arrow) retorectal intussusception.

*

References:1. PALIT et al. 2012. The physiology of defecation. Dig Dis Sci (2012) 57:1445–14642. COLLINSON, R. et al. 2009. Rectal intussusception and unexplained faecal incontinence: findings of a

proctographic study. Colorectal dis, 11; 77-833. Lalwani N et al. 2019. Imaging and clinical assessment of functional defecatory disorders with emphasis

on defecography. Abdom Radiol (NY). 2019 Jul 22.

Figure 2:

The X ray machine and proctogramchair are aligned such that sagittal images are obtained of the patient during the study.