A.O. CHURAKOVA¹, R.I. GABIDULLINA^1, 2, F.I. FATKULLIN^1, 2, T.N. SHIGABUTDINOVA²

 ¹Kazan State Medical University, Kazan

²City Clinical Hospital No. 7 named after M.N. Sadykov, Kazan

Contact details:

Gabidullina R.I. — MD, Professor, Head of the Department of Obstetrics and Gynecology named after V.S. Gruzdev

Address: 49 Butlerov St., 420012 Kazan, Russian Federation, tel.: +7 (843) 236-06-23, e-mail: ru.gabidullina@yandex.ru

The purpose — to systematize current data on the impact of cesarean section surgical techniques on uterine scar healing, niche formation, residual myometrial thickness, and the risk of urological complications. We conducted an analytical review of randomized controlled trials, systematic reviews, meta-analyses, and clinical guidelines based on the search in national electronic resources and international systems (eLIBRARY, PubMed, MedLine, Crossref, and Google Scholar) from 2009 to 2026.

Results. Scar niche formation is associated with the features of the surgical technique — the incision level and the myometrial suturing method. However, a convincing association between residual myometrial thickness and adverse obstetric outcomes is not proven. Impaired subendometrial peristalsis and endometrial involvement in the suture may contribute to defective healing. Refusal to routinely form a vesical flap does not increase the complication rate and reduces the surgical time.

Conclusions. Caesarean section technique influences scar formation and complication rates. Optimizing the incision, myometrial suturing, and manipulation of the vesicouterine fold reduces the risk of niche formation and urological damage. Further prospective studies with a standardized assessment of scar formation and reproductive outcomes are needed.

Key words: niche formation, isthmocele, uterine suture, residual myometrial thickness, vesical flap

REFERENCES

1. Betrán A.P., Ye J., Moller A.B. et al. The increasing trend in caesarean section rates: global, regional and national estimates: 1990–2014. PLoS One, 2016, vol. 11 (2). e0148343. DOI: 10.1371/journal.pone.0148343
2. Boerma T., Ronsmans C., Melesse D.Y. et al. Global epidemiology of use of and disparities in caesarean sections. Lancet, 2018, vol. 392 (10155), pp. 1341–1348. DOI: 10.1016/S0140-6736(18)31928-7
3. Qiao L., Lu J., Zhang B., Liu A., Wang X., Wang M. et al. Accuracy of multimodal vaginal ultrasound in the detection and assessment of scar healing after caesarean section: a correlational meta-analysis. Ann. Med, 2025, vol. 57 (1). 2523558. DOI: 10.1080/07853890.2025.2523558
4. Vervoort A.J., Uittenbogaard L.B., Hehenkamp W.J. et al. Why do niches develop in Caesarean uterine scars? Hypotheses on the aetiology of niche development. Hum. Reprod., 2015, vol. 30 (12), pp. 2695–2702. DOI: 10.1093/humrep/dev240
5. Meyer J.A., Silverstein J., Timor-Tritsch I.E. et al. The effect of uterine closure technique on cesarean scar niche development after multiple cesarean deliveries. J. Perinat. Med., 2023, vol. 52 (2), pp. 150–157. DOI: 10.1515/jpm-2023-0211
6. Dominoni M., Torella M., Molitierno R. et al. Single-versus double-layer uterine closure at the time of cesarean delivery and risk of uterine scar niche: a systematic review and meta-analysis of randomized trials. Arch. Gynecol. Obstet, 2025, vol. 312 (4), pp. 1095–1106. DOI: 10.1007/s00404-025-08151-y
7. Gialdini C., Chamillard M., Diaz V. et al. Evidence-based surgical procedures to optimize caesarean outcomes: an overview of systematic reviews. EClinicalMedicine, 2024, vol. 72. 102632. DOI: 10.1016/j.eclinm.2024.102632
8. Swift B.E., Shah P.S., Farine D. Sonographic lower uterine segment thickness after prior cesarean section to predict uterine rupture: A systematic review and meta-analysis. Acta Obstet. Gynecol. Scand, 2019, vol. 98 (7), pp. 830–841. DOI: 10.1111/aogs.13585
9. Ramasauskaite D., Nassar A., Ubom A.E. et al. FIGO Childbirth and Postpartum Hemorrhage Committee. FIGO good practice recommendations for cesarean delivery on maternal request: Challenges for medical staff and families. Int. J. Gynaecol. Obstet, 2023, vol. 163 (suppl 2), pp. 10–20. DOI: 10.1002/ijgo.15118
10. ACOG Practice Bulletin No. 205: Vaginal Birth After Cesarean Delivery. Obstet. Gynecol, 2019, vol. 133 (2), pp. e110–e127. DOI: 10.1097/AOG.0000000000003078
11. 2021 exceptional surveillance of caesarean birth — maternal request (NICE guideline NG192). London: National Institute for Health and Care Excellence (NICE), 2021.
12. CORONIS Collaborative Group; Abalos E., Addo V., Brocklehurst P. et al. Caesarean section surgical techniques (CORONIS): a fractional, factorial, unmasked, randomised controlled trial. Lancet, 2013, vol. 382 (9888), pp. 234–248. DOI: 10.1016/S0140-6736(13)60441-9
13. CORONIS collaborative group; Abalos E., Addo V., Brocklehurst P. et al. Caesarean section surgical techniques: 3 year follow-up of the CORONIS fractional, factorial, unmasked, randomised controlled trial. Lancet, 2016, vol. 388 (10039), pp. 62–72. DOI: 10.1016/S0140-6736(16)00204-X
14. Dodd J., Anderson E., Gates S., Grivell R. Surgical techniques for uterine incision and uterine closure at the time of caesarean section. Cochrane Database Syst. Rev., 2014, no. 7. CD004732. DOI:10.1002/14651858.CD004732.pub3
15. Dahlke J.D., Mendez-Figueroa H., Maggio L. et al. Prevention and management of postpartum hemorrhage: a comparison of 4 national guidelines. Am. J. Obstet. Gynecol, 2015, vol. 213 (1), pp. 76.e1–76.e10. DOI: 10.1016/j.ajog.2015.02.023
16. Spong C.Y., Landon M.B., Gilbert S. et al. National Institute of Child Health and Human Development (NICHD) Maternal-Fetal Medicine Units (MFMU) Network. Risk of uterine rupture and adverse perinatal outcome at term after cesarean delivery. Obstet. Gynecol, 2007, vol. 110 (4), pp. 801–807. DOI: 10.1097/01.AOG.0000284622.71222.b2
17. Betran A.P., Torloni M.R., Zhang J.J. et al.; WHO Working Group on Caesarean Section. WHO Statement on caesarean section rates. BJOG, 2016, vol. 123 (5), pp. 667–670. DOI: 10.1111/1471-0528.13526
18. Qayum K., Kar I., Sofi J. et al. Single-versus double-layer uterine closure after cesarean section delivery: a systematic review and meta-analysis. Cureus, 2021, vol. 13 (9), p. e18405. DOI: 10.7759/cureus.18405
19. Barnea E.R., Inversetti A., Di Simone N. FIGO Childbirth and Postpartum Hemorrhage Committee. FIGO good practice recommendations for cesarean delivery: Prep-for-Labor triage to minimize risks and maximize favorable outcomes. Int. J. Gynaecol. Obstet, 2023, vol. 163 (suppl 2), pp. 57–67. DOI: 10.1002/ijgo.15115
20. Verberkt C.A., Stegwee S.I., Van der Voet L.F. et al. 2Close Study Group. Single-layer vs double-layer uterine closure during cesarean delivery: 3-year follow-up of a randomized controlled trial (2Close study). Am. J. Obstet. Gynecol, 2024, vol. 230 (4), pp. 401.e1–401.e11. DOI: 10.1016/j.ajog.2023.10.019
21. Jordans I.P.M., de Leeuw R.A., Stegwee S.I. et al. Sonographic examination of uterine niche in non-pregnant women: a modified Delphi procedure. Ultrasound Obstet. Gynecol., 2019, vol. 53 (1), pp. 107–115. DOI: 10.1002/uog.19049
22. Babu K., Magon N. Uterine closure in cesarean delivery: a new technique. N Am. J. Med. Sci, 2012, vol. 4 (8), pp. 358–361. DOI: 10.4103/1947-2714.99519
23. Vejnović T.R., Costa S.D., Ignatov A. New technique for caesarean section. Geburtshilfe Frauenheilkd, 2012, vol. 72 (9), pp. 840–845. DOI: 10.1055/s-0032-1315347
24. Kabatin N.A., Kalinin V.V., Sorokina A.L. Clinical experience of using the T. Vejnovic technique for uterine suturing after cesarean section. Akusherstvo i ginekologiya, 2021, no. 1, pp. 88–93 (in Russ.). DOI: 10.18565/aig.2021.1.88-93
25. Klein Meuleman S.J.M., Murji A., van den Bosch T. et al. CSDi Study Group. Definition and criteria for diagnosing cesarean scar disorder. JAMA Netw. Open, 2023, vol. 6 (3). e235321. DOI: 10.1001/jamanetworkopen.2023.5321
26. Budny-Winska J., Pomorski M. Uterine niche after cesarean section: a review of diagnostic methods. Ginekol. Pol, 2021, vol. 92 (10), pp. 726–730. DOI: 10.5603/GP.a2021.0195
27. Soares D.M., Junior H.W., Bittencourt L.K., Lopes F.P.P.L., de Oliveira M.A.P. The role of cine MR imaging in the assessment of uterine function. Arch. Gynecol. Obstet, 2019, vol. 300 (3), pp. 545–553. DOI: 10.1007/s00404-019-05222-9
28. Di Spiezio Sardo A., Saccone G., McCurdy R. et al. Risk of Cesarean scar defect following single- vs double-layer uterine closure: systematic review and meta-analysis of randomized controlled trials. Ultrasound Obstet. Gynecol, 2017, vol. 50 (5), pp. 578–583. DOI: 10.1002/uog.17401
29. Bamberg C., Dudenhausen J.W., Bujak V. et al. A prospective randomized clinical trial of single vs. double layer closure of hysterotomy at the time of cesarean delivery: the effect on uterine scar thickness. Ultraschall Med, 2018, vol. 39 (3), pp. 343–351. DOI: 10.1055/s-0042-112223
30. Stegwee S.I., Jordans I.P.M., van der Voet L.F. et al. Single-versus double-layer closure of the caesarean (uterine) scar in the prevention of gynaecological symptoms in relation to niche development — the 2Close study: a multicentre randomised controlled trial. BMC Pregnancy Childbirth, 2019, vol. 19 (1), p. 85. DOI: 10.1186/s12884-019-2221-y
31. Mashiach R., Burke Y.Z. Optimal isthmocele management: hysteroscopic, laparoscopic, or combination. J. Minim. Invasive Gynecol, 2021, vol. 28 (3), pp. 565–574. DOI: 10.1016/j.jmig.2020.10.026
32. Mackeen A.D., Sullivan M.V., Berghella V. Evidence-based cesarean delivery: intraoperative management from skin incision until placental delivery (Part 8). Am. J. Obstet. Gynecol. MFM, 2025, vol. 7 (1). 101576. DOI: 10.1016/j.ajogmf.2024.101576
33. Dahlke J.D., Mendez-Figueroa H., Maggio L. et al. The case for standardizing cesarean delivery technique: seeing the forest for the trees. Obstet. Gynecol, 2020, vol. 136 (5), pp. 972–980. DOI: 10.1097/AOG.0000000000004120
34. Omar Mona, Farahat Manal. Omission of the bladder flap suggests short term and long-term benefits. Open J. Obstet. Gynecol, 2019, no. 9, pp. 566–577. DOI: 10.4236/ojog.2019.95055
35. Gupta P., Kumari S. Comparative study to assess the outcome of omitting bladder flap formation from caesarean delivery. Int. J. Reprod. Contracep. Obstet. Gynecol, 2019, vol. 8 (3), p. 882. DOI: 10.18203/2320-1770.ijrcog20190849
36. O’Boyle A.L., Mulla B.M., Lamb S.V. et al. Urinary symptoms after bladder flap at the time of primary cesarean delivery: a randomized controlled trial (RTC). Int. Urogynecol. J, 2018, vol. 29 (2), pp. 223–228. DOI: 10.1007/s00192-017-3369-5
37. Gül K., Şolt A. Effects of creation of bladder flap during cesarean section on long-term residual urine volume and postoperative urinary retention. J. Surg. Med, 2020, vol. 4 (12), pp. 1190–1194. DOI: 10.28982/josam.832595
38. Saaqib S., Iqbal A., Naheed M. et al. A randomized controlled trial of cystoinflation to prevent bladder injury in the adhesive disease of multiple caesarean sections. Sci. Rep, 2020, vol. 10 (1), p. 15297. DOI: 10.1038/s41598-020-71132-5
39. Ibrahim N., Spence A.R., Czuzoj-Shulman N. et al. Incidence and risk factors of bladder injury during cesarean delivery: a cohort study. Arch. Gynecol. Obstet, 2023, vol. 307 (2), pp. 401–408. DOI: 10.1007/s00404-022-06447-x
40. Pelosi M.A. 2nd, Pelosi M.A. 3rd. The Pelosi cesarean delivery technique. Am. J. Obstet. Gynecol, 2026, vol. 233 (6S), pp. S69–S81. DOI: 10.1016/j.ajog.2025.07.047