title: High-resolution Anorectal Manometry for Identifying Defecatory Disorders and Rectal Structural Abnormalities in Women.
abstract: Contrary to conventional wisdom, the rectoanal gradient during evacuation is negative in many healthy people, undermining the utility of anorectal high-resolution manometry (HRM) for diagnosing defecatory disorders. We aimed to compare HRM and magnetic resonance imaging (MRI) for assessing rectal evacuation and structural abnormalities.
  
  
  
  We performed a retrospective analysis of 118 patients (all female; 51 with constipation, 48 with fecal incontinence, and 19 with rectal prolapse; age, 53 ± 1 years) assessed by HRM, the rectal balloon expulsion test (BET), and MRI at Mayo Clinic, Rochester, Minnesota, from February 2011 through March 2013. Thirty healthy asymptomatic women (age, 37 ± 2 years) served as controls. We used principal components analysis of HRM variables to identify rectoanal pressure patterns associated with rectal prolapse and phenotypes of patients with prolapse.
  
  
  
  Compared with patients with normal findings from the rectal BET, patients with an abnormal BET had lower median rectal pressure (36 vs 22 mm Hg, P = .002), a more negative median rectoanal gradient (-6 vs -29 mm Hg, P = .006) during evacuation, and a lower proportion of evacuation on the basis of MRI analysis (median of 40% vs 80%, P < .0001). A score derived from rectal pressure and anorectal descent during evacuation and a patulous anal canal was associated (P = .005) with large rectoceles (3 cm or larger). A principal component (PC) logistic model discriminated between patients with and without prolapse with 96% accuracy. Among patients with prolapse, there were 2 phenotypes, which were characterized by high (PC1) or low (PC2) anal pressures at rest and squeeze along with higher rectal and anal pressures (PC1) or a higher rectoanal gradient during evacuation (PC2).
  
  
  
  In a retrospective analysis of patients assessed by HRM, measurements of rectal evacuation by anorectal HRM, BET, and MRI were correlated. HRM alone and together with anorectal descent during evacuation may identify rectal prolapse and large rectoceles, respectively, and also identify unique phenotypes of rectal prolapse.
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research Program, Mayo Clinic, Rochester, Minnesota.
authors.forename: David O
authors.initials: DO
authors.lastname: Prichard
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research Program, Mayo Clinic, Rochester, Minnesota.
authors.forename: Taehee
authors.initials: T
authors.lastname: Lee
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research Program, Mayo Clinic, Rochester, Minnesota.
authors.forename: Gopanandan
authors.initials: G
authors.lastname: Parthasarathy
authors.affiliation: Department of Radiology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Joel G
authors.initials: JG
authors.lastname: Fletcher
authors.affiliation: Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Zinsmeister
authors.affiliation: Clinical Enteric Neuroscience Translational and Epidemiological Research Program, Mayo Clinic, Rochester, Minnesota. Electronic address: bharucha.adil@mayo.edu.
authors.forename: Adil E
authors.initials: AE
authors.lastname: Bharucha
mesh_terms: D000328:Adult; D000368:Aged; D003672:Defecation / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008365:Manometry / Q000379:methods*; D008875:Middle Aged; D008910:Minnesota; D012002:Rectal Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012007:Rectum / Q000002:abnormalities*; D012189:Retrospective Studies
keywords: Anismus; Balloon Expulsion; Diagnosis; Pelvic Floor Dysfunction