Evaluation of the Anopress® device in assessment of obstetric anal sphincter injuries in a specialist urogynaecology service

Published:November 24, 2020DOI:


      • Women with obstetric anal sphincter injuries should be offered postnatal follow up.
      • History, examination, endoanal ultrasound and anal manometry are important in the evaluation of these women.
      • Anopress is a new portable anal manometry device which can be used in an outpatient clinic setting.
      • This study shows that anal canal pressures measured with Anopress appear to correlate well with symptoms and endoanal ultrasound findings in women with obstetric anal sphincter injury.
      • Anopress may be useful in setting up one-stop specialist perineal clinics, reducing hospital attendances.



      THD Anopress® is a new portable anal manometry device which can be used in an outpatient clinic setting. In this study, we aimed to:
      • Evaluate anal canal resting average pressure (RAVP) and maximal squeeze pressure (MSP) as measured with Anopress in women with Obstetric Anal Sphincter Injury (OASI).
      • Study the relationship between anal canal pressures measured with Anopress with patient symptoms and Endoanal Ultrasound Scan (EAUSS) findings.

      Study design

      A retrospective analysis was conducted of women with OASI seen in a specialist clinic at 3- and 6-months post-delivery from November 2016 to December 2019. 72 women who attended their 6-month appointment and underwent anal manometry with Anopress were included. St Mark’s Faecal incontinence score (FI) was calculated and for the purpose of analysis patients were classified into two groups – FI score less than 5 and 5 or more. EAUSS findings were classified as sphincter defect or no defect. RAVP and MSP were measured with Anopress and compared with the variables (symptoms and EAUSS findings) using the Mann-Whitney U test.


      A total of 72 women were included in the study. There were 19 (27 %), 41 (57 %), 6 (8 %) and 6 (8 %) 3a, 3b, 3c and 4th degree perineal tears respectively. The median RAVP was 17 mm Hg (Inter-Quartile Range 10.75–24 mmHg) and median MSP was 47.5 mm Hg (IQR 33−68 mmHg).
      38 patients (53 %) had a demonstrable sphincter defect on EAUSS. 37 patients (51.3 %) had FI score < 5 and 35 patients (48.6 %) had FI score of 5 or more. RAVP and MSP were significantly lower with EAUSS demonstrable sphincter defect (p < 0.001). Symptom severity correlated with RAVP (p = 0.016) though its correlation with MSP was not statistically significant (p = 0.096).


      Anopress seems promising in the assessment of anal sphincter function in women with OASI and can potentially make anal manometry testing easily accessible to urogynecologists.


      RAVP (Anal canal resting average pressure), MSP (Maximum squeeze pressure), OASI (Obstetric anal sphincter injury), EAUSS (Endo-anal ultrasound scan), FI (St Mark’s Faecal incontinence score), IQR (Inter-quartile range), ePAQ-PF (electronic personal assessment questionnaire – pelvic floor), EAS (external anal sphincter), IAS (internal anal sphincter)


      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


        • Turel F.D.
        • Langer S.
        • Shek K.L.
        • Dietz H.P.
        Medium- to long-term follow-up of obstetric anal sphincter injury.
        Dis Colon Rectum. 2019; 62: 348-356
        • Sultan A.H.
        • Kamm M.A.
        • Hudson C.N.
        • Thomas J.M.
        • Bartram C.I.
        Anal-sphincter disruption during vaginal delivery.
        N Engl J Med. 1993; 329: 1905-1911
        • RCOG
        The management of third- and fourth-degree perineal tears. Green top guideline no 29June.
        • Heinrich H.
        • Misselwitz B.
        High-resolution anorectal manometry - new insights in the diagnostic assessment of functional anorectal disorders.
        Visc Med. 2018; 34: 134-139
        • Lee T.H.
        • Bharucha A.E.
        How to perform and interpret a high-resolution anorectal manometry test.
        J Neurogastroenterol Motil. 2016; 22: 46-59
        • Carrington E.V.
        • Scott S.M.
        • Bharucha A.
        • Mion F.
        • Remes-Troche J.M.
        • Malcolm A.
        • et al.
        Advances in the evaluation of anorectal function.
        Nat Rev Gastroenterol Hepatol. 2018; 15: 309-323
      1. Italy TS. THD Anopress. In:, editor.

        • AH. S
        Obstetric perineal injury and anal incontinence.
        Clin Risk. 1999; : 193-196
        • Vaizey C.J.
        • Carapeti E.
        • Cahill J.A.
        • Kamm M.A.
        Prospective comparison of faecal incontinence grading systems.
        Gut. 1999; 44: 77-80
        • Jones G.L.
        • Radley S.C.
        • Lumb J.
        • Jha S.
        Electronic pelvic floor symptoms assessment: tests of data quality of ePAQ-PF.
        Int Urogynecol J Pelvic Floor Dysfunct. 2008; 19: 1337-1347
        • McCooty S.
        • Latthe P.
        Electronic pelvic floor assessment questionnaire: a systematic review.
        Br J Nurs. 2014; 23: S32-7
        • Dobben A.C.
        • Terra M.P.
        • Deutekom M.
        • Gerhards M.F.
        • Bijnen A.B.
        • Felt-Bersma R.J.F.
        • et al.
        Anal inspection and digital rectal examination compared to anorectal physiology tests and endoanal ultrasonography in evaluating fecal incontinence.
        Int J Colorectal Dis. 2007; 22: 783-790
        • Law P.J.
        • Bartram C.I.
        Anal endosonography: technique and normal anatomy.
        Gastrointest Radiol. 1989; 14: 349-353
        • Leo C.A.
        • Cavazzoni E.
        • Thomas G.P.
        • Hodgkison J.
        • Murphy J.
        • Vaizey C.J.
        Evaluation of 153 asymptomatic subjects using the anopress portable anal manometry device.
        J Neurogastroenterol Motil. 2018; 24: 431-436
        • Dickinson K.J.
        • Pickersgill P.
        • Anwar S.
        Functional and physiological outcomes following repair of obstetrics anal sphincter injury. A case.
        Int J Surg. 2013; 11: 1137-1140
        • Leo C.
        • Murphy J.
        • Cavazzoni E.
        • Thomas G.
        • Shaikh S.
        • Hodgkinson J.
        • et al.
        Evaluation of the portable THD® anopress device in patients with faecal incontinence.
        2018: 8
        • Leo C.A.
        • Cavazzoni E.
        • Leeuwenburgh M.M.N.
        • Thomas G.P.
        • Dennis A.
        • Bassett P.
        • et al.
        Comparison between high-resolution water-perfused anorectal manometry and THD((R)) Anopress anal manometry: a prospective observational study.
        Colorectal Dis. 2020;