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Anal sphincter tear — Clinical Guidelines

Overview

Obstetric anal sphincter injury (OASIS) involves damage to the anal sphincter muscles during vaginal delivery, often leading to fecal incontinence and other pelvic floor dysfunctions. Proper diagnosis and management are crucial for improving patient outcomes 1 2 3 4.

Diagnosis

Key Diagnostic Criteria: Identification of sphincter tear during delivery, clinical signs of perineal trauma, and symptoms of incontinence 1 2 3.

Recommended Tests: Endoanal ultrasound (EAUS) and transperineal ultrasound (TPUS) for assessing sphincter integrity and defect angles 7.

Grading: Classification based on the extent of injury (e.g., third-degree, fourth-degree) 27.

Management

First-Line Treatments: Surgical repair by experienced obstetricians using techniques like end-to-end anastomosis 24.

Antibiotics: Use of metronidazole during repair remains debated; evidence is limited 14.

Rehabilitation: Pelvic floor physiotherapy recommended post-repair to enhance recovery 1 2 3.

Follow-Up: Regular anorectal evaluations, including EAUS, to monitor sphincter integrity and functional outcomes 4 7 26.

Special Populations

Pregnancy: Perineal protection techniques and mode of delivery choices in subsequent pregnancies vary among practitioners 1 21.

Operator Experience: Higher risk of OASIS in vacuum extraction deliveries with less experienced operators 16.

Key Recommendations

Implement Simulation Training: Use of simulation models significantly improves residents' skills in repairing OASIS (Evidence: Moderate) 1 6 8 19.

Enhance Resident Exposure: Increase exposure to OASIS repair during residency training to improve competency (Evidence: Moderate) 2 17.

Perineal Protection Programs: Adoption of perineal protection programs can reduce OASIS incidence (Evidence: Moderate) 20.

Regular Post-Repair Evaluation: Conduct regular anorectal evaluations, including EAUS, to assess long-term outcomes (Evidence: Moderate) 4 26.

Consider Mode of Delivery Carefully: In subsequent pregnancies, consider mode of delivery based on individual risk factors and practitioner expertise (Evidence: Expert opinion) 21.

References

1 Wahyuningtyas R, Kurniawati EM, Hardianto G, Paraton H, Hadi THS, Kuswanto D. Randomized Comparison of Video Demonstration, Simulation-Based Training, and Combination Using Silicone-Latex Simulation for Anal Sphincter Injury Repair in Obstetrics and Gynecology Residents. International urogynecology journal 2025. link 2 Pfeuti CK, Gugerty L, Occhino JA, Chauhan SP. Residents' Exposure to Obstetric Anal Sphincter Injury: A 16-Year Temporal Trend. Urogynecology (Philadelphia, Pa.) 2025. link 3 Cormier J, Mirouse L, Barbot J, Goffinet F, Le Ray C. Evolution of Episiotomy Incidence and Obstetric Anal Sphincter Injury Over 10 Years: A Mixed-Methods Study. BJOG : an international journal of obstetrics and gynaecology 2025. link 4 Elsaid N, Thomas GP, Dutta S, Fernando RJ, Carrington EV, Vaizey CJ. Care pathways and anorectal evaluation for obstetric anal sphincter injury-related incontinence: A UK survey of obstetricians. Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland 2025. link 5 Muraca GM, Desai A, Hébert V, Mann GK, Park M, Lisonkova S et al.. Variation in Episiotomy Use Among Nulliparous Individuals by Maternity Care Provider and Associated Rates of Obstetric Anal Sphincter Injury. Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC 2024. link 6 Tang P, Zhong Y, Yin J, Song Y. Effects of a structural simulation curriculum for the repair of obstetrical anal sphincter injuries. International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics 2023. link 7 Okeahialam NA, Thakar R, Sultan AH. Comparison of diagnostic criteria for significant anal sphincter defects between endoanal and transperineal ultrasound. Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology 2022. link 8 Wahyuningtyas R, Kurniawati EM, Utomo B, Hardianto G, Paraton H, Hastono T et al.. Obstetrics and gynecology residents' satisfaction and self-confidence after anal sphincter injury simulation-based workshop in Indonesia: a pre- and post-intervention comparison study. Journal of educational evaluation for health professions 2022. link 9 Baumfeld Y, Yohay D, Rotem R, Yohay Z, Weintraub AY. Temporal decline in the improved detection rates following OASIS workshops. International urogynecology journal 2021. link 10 Gachon B, Schmitz T, Artzner F, Parant O, De Tayrac R, Ducarme G et al.. A core outcome set development for a French national prospective study about the effect of mediolateral episiotomy on obstetric anal sphincter injury during operative vaginal delivery (INSTRUMODA). BMC pregnancy and childbirth 2021. link 11 Eston M, Stephenson-Famy A, McKenna H, Fialkow M. Perineal Laceration and Episiotomy Repair Using a Beef Tongue Model. MedEdPORTAL : the journal of teaching and learning resources 2020. link 12 Divakova O, Khunda A, Ballard PA. Episcissors-60™ and obstetrics anal sphincter injury: a systematic review and meta-analysis. International urogynecology journal 2020. link 13 Kim EK, Lovejoy DA, Patterson D, Handa VL. Lessons Learned From a Review of Malpractice Litigations Involving Obstetric Anal Sphincter Injury in the United States. Female pelvic medicine & reconstructive surgery 2020. link 14 Rotem R, Mastrolia SA, Rottenstreich M, Yohay D, Weintraub AY. The use of metronidazole in women undergoing obstetric anal sphincter injuries: a systematic review of the literature. Archives of gynecology and obstetrics 2020. link 15 Ducarme G, Pizzoferrato AC, de Tayrac R, Schantz C, Thubert T, Le Ray C et al.. Perineal prevention and protection in obstetrics: CNGOF clinical practice guidelines. Journal of gynecology obstetrics and human reproduction 2019. link 16 Bergendahl S, Lindberg P, Brismar Wendel S. Operator experience affects the risk of obstetric anal sphincter injury in vacuum extraction deliveries. Acta obstetricia et gynecologica Scandinavica 2019. link 17 Abdelrahman M, Geary M, Eogan M. Obstetric Anal Sphincter Injuries: A Survey of Clinical Practice and Education among Obstetricians and Gynaecologists in Ireland. Irish medical journal 2019. link 18 Stecher AM, Yeung J, Crisp CC, Pauls RN. Awareness Regarding Perineal Protection, Obstetric Anal Sphincter Injury, and Episiotomy Among Obstetrics and Gynecology Residents; Effects of an Educational Workshop. Female pelvic medicine & reconstructive surgery 2018. link 19 Knobel R, Volpato LK, Gervasi LC, Viergutz RA, Trapani A. A Simple, Reproducible and Low-cost Simulator for Teaching Surgical Techniques to Repair Obstetric Anal Sphincter Injuries. Revista brasileira de ginecologia e obstetricia : revista da Federacao Brasileira das Sociedades de Ginecologia e Obstetricia 2018. link 20 Yeung J, Stecher A, Crisp CC, Mazloomdoost D, Smith B, Kleeman SD et al.. Incidence of Obstetric Anal Sphincter Injuries After Training to Protect the Perineum. Female pelvic medicine & reconstructive surgery 2018. link 21 Donners JJAE, Kluivers KB, de Leeuw JW, van Dillen J, van Kuijk SMJ, Weemhoff M. Choice of mode of delivery in a subsequent pregnancy after OASI: a survey among Dutch gynecologists. International urogynecology journal 2017. link 22 Rahman N, Vinayakarao L, Pathak S, Minden D, Melson L, Vitue E et al.. Evaluation of training programme uptake in an attempt to reduce obstetric anal sphincter injuries: the SUPPORT programme. International urogynecology journal 2017. link 23 Temtanakitpaisan T, Bunyacejchevin S, Koyama M. Obstetrics anal sphincter injury and repair technique: a review. The journal of obstetrics and gynaecology research 2015. link 24 Salim R, Peretz H, Molnar R, Braverman M, Hatokay A, Shalev E. Long-term outcome of obstetric anal sphincter injury repaired by experienced obstetricians. International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics 2014. link 25 Evans C, Archer R, Forrest A, Barrington J. Management of obstetric anal sphincter injuries (OASIS) in subsequent pregnancy. Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology 2014. link 26 Pronk P, van Leeuwen E, Albicher C, Dermout SM, Doornbos JP, Engel AF. Temporal endosonographic evaluation of anal sphincter integrity after primary repair for obstetric ruptures: a case for specific training of obstetricians. Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland 2010. link 27 Uppal S, Harmanli O, Rowland J, Hernandez E, Dandolu V. Resident competency in obstetric anal sphincter laceration repair. Obstetrics and gynecology 2010. link 28 Chao TT, Wendel GD, McIntire DD, Corton MM. Effectiveness of an instructional DVD on third- and fourth-degree laceration repair for obstetrics and gynecology postgraduate trainees. International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics 2010. link 29 Rottenberg GT, Williams AB. Endoanal ultrasound. The British journal of radiology 2002. link 30 Fernando RJ, Sultan AH, Radley S, Jones PW, Johanson RB. Management of obstetric anal sphincter injury: a systematic review & national practice survey. BMC health services research 2002. link

Anal sphincter tear