Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Jun;33(6):1473-1479.
doi: 10.1007/s00192-021-05051-y. Epub 2022 Feb 12.

Under-classified obstetric anal sphincter injuries

Joanna C Roper  1 , Ranee Thakar  1   2 , Abdul H Sultan  3   4
Affiliations

Under-classified obstetric anal sphincter injuries

Joanna C Roper et al. Int Urogynecol J. 2022 Jun.

Abstract

Introduction and hyposthesis: Obstetric anal sphincter injuries (OASIs) that are missed at delivery can have long-term consequences. OASIs that are under-classified at delivery are likely to be inadequately repaired, resulting in a persistent anal sphincter defect. We aimed to identify women who have persistent defects on endoanal ultrasound, inconsistent with the original diagnosis, and compare the effect on St Mark's incontinence scores (SMIS). We also aimed to look for changes in numbers of under-classification over time.

Methods: Records of women attending a perineal clinic who had endoanal ultrasound from 2012 to 2020 were reviewed. Women who had a modified Starck score implying a defect greater than the classification [indicated by the depth of external anal sphincter or internal anal sphincter (IAS) defect] at delivery were identified.

Results: A total of 1056 women with a diagnosis of 3a or 3b tears were included. Of these, 120 (11.36%) were found to have a defect greater than the original diagnosis and therefore were incorrectly classified at delivery. Women who had a 3b tear diagnosed at delivery, but had an IAS defect, had a significantly higher SMIS (p < 0.01). When comparing two 4-year periods, there was a significant improvement in the diagnosis of IAS tears.

Conclusion: Some women with OASIs that have under-classified OASIs are associated with worse anorectal symptoms. This is likely because of an incomplete repair. Some improvement in diagnosis of IAS tears has been noted. We propose improved training in OASIs can help reduce the number of incorrectly classified tears and improve repair.

Keywords: Diagnosis of third-degree tears; Endoanal ultrasound; Obstetric anal sphincter injuries; St Mark’s incontinence score; Starck score.

PubMed Disclaimer

References

    1. Royal College of Obstetrics and Gynaecology. Management of third and fourth degree perineal tears. Greentop guideline number 29 2015.
    1. Sultan AH. Editorial: obstetrical perineal injury and anal incontinence. AVMA Medical & Legal Journal. 1999;5:193–6. https://doi.org/10.1177/135626229900500601 . - DOI
    1. Roper JC, Sultan AH, Thakar R. Diagnosis of perineal trauma: getting it right first time. Br J Midwifery. 2020;28:710–7. https://doi.org/10.12968/bjom.2020.28.10.710 . - DOI
    1. Andrews V, Sultan AH, Thakar R, Jones PW. Occult anal sphincter injuries—myth or reality? BJOG. 2006;113:195–200. https://doi.org/10.1111/j.1471-0528.2006.00799.x . - DOI - PubMed
    1. Sioutis D, Thakar R, Sultan AH. Overdiagnosis and rising rate of obstetric anal sphincter injuries (OASIS): time for reappraisal. Ultrasound Obstet Gynecol. 2017;50:642–7. https://doi.org/10.1002/uog.17306 . - DOI - PubMed