Journal of Neurogastroenterology and Motility : eISSN 2093-0887 / pISSN 2093-0879

Table. 2.

Evidence-based Summary of the Utility of the Diagnostic Tests in Patients With Suspected Colonic or Anorectal Motility Disorders (Modified From Sackett73)

Test Clinical utility Strength/Weakness Comment
Blood tests (basic metabolic panel, complete blood count, thyroid function tests, etc) Rule out systemic or metabolic disorder Low yield Not recommended for routine evaluation particularly in the absence of alarm features
Easily obtainable in the clinic Likely not cost-effective strategy
Imaging tests
Plain abdominal X-ray Identify excessive amount of stool in the colon Lack of controlled studies Recommended for routine evaluation particularly in the absence of alarm features
Simple, inexpensive, widely available Purely qualitative data
Barium enema Identify megacolon, megarectum, stenosis, diverticulosis, extrinsic compression and intraluminal masses High radiation exposure Not recommended for routine evaluation particularly in the absence of alarm features
Difficult to tolerate for patients
Expensive
Defecography Recognize dyssynergia, rectocele and prolapse, excessive descent, megarectum, Hirschsprung’s disease High radiation exposure Used as an adjunct to anorectal manometry
Tolerability
Inconsistent methodology
Anorectal ultrasound Visualization of the internal anal sphincter and puborectalis muscles Interobserver bias Primarily experimental
Low availability
MRI Simultaneous evaluation of global pelvic floor anatomy and dynamic motion Expensive Used as an adjunct to anorectal manometry
Lack of standardization
Reveals pathology outside anorectum and sphincter morphology Likely not cost effective
Endoscopy
Flexible sigmoidoscopy and colonoscopy Direct visualization of the colon to exclude mucosal lesions such as solitary rectal ulcer syndrome, inflammation, or malignancy Invasive Indicated in patients with warning symptoms in patients under 50 years
Risks of procedure
Typically not high yield in cases of constipation and anorectal pain Indicated in all subjects older than 50 years for colorectal cancer screening
Physiologic testing
Colonic transit study with radiopaque markers Evaluate presence of slow, normal or rapid colonic transit Inconsistent methodology Useful to classify patients according to the pathophysiological subtypes
Questionable validity
Colonic transit study with scintigraphy Inexpensive and widely available Radiation Useful to classify patients according to the pathophysiological subtypes
Evaluate presence of slow, normal, or rapid colonic transit Expensive
Time consuming
Provide evaluation of the whole gut transit Low availability
Radiation
Wireless motility capsule Evaluate presence of slow, normal, or rapid colonic transit Standardized method Useful to categorize patients into slow transit and normal transit
Limited availability in North America and Europe Identifies upper GI dysmotility
Provides evaluation of regional (gastric, small bowel) and whole gut transit time No radiation Testing performed under physiological conditions
Anorectal manometry Identify dyssynergic defecation, rectal hyposensitivity, rectal hypersensitivity, impaired compliance, Hirschsprung’s disease Can be uncomfortable for patients Useful to establish the diagnoses of Hirschsprung’s disease and dyssynergic defecation
Low availability
Questionable standardization Identify rectal hyposensitivity and rectal hypersensitivity in IBS
Balloon expulsion test Simple, non expensive, bedside assessment of the ability to expel a simulated stool Lack of standardization Normal balloon expulsion test does not exclude dyssynergia
Identify dyssynergic defecation Should be interpreted alongside the results of the other anorectal tests
Colonic manometry Identify colonic myopathy, neuropathy or normal function facilitating selection of patients for surgery Invasive, not widely available, lack of standardization Adjunct to colorectal function tests
Translumbosacral anorectal magnetic stimulation Measures conduction velocity of spinal nerves responsible for defecation Standardized Able to identify lumbar plexus and sacral plexus neuropathy contributing to lower GI symptoms, particularly fecal incontinence and anorectal pain disorders
Not widely available Identify neuropathy at rectum and anal region

GI, gastrointestinal; IBS, irritable bowel syndrome.

J Neurogastroenterol Motil 2020;26:423~436 https://doi.org/10.5056/jnm20012
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