The Impact of Uterine Incision Closure Techniques on Post-cesarean Delivery Niche Formation and Size: Sonohysterographic Examination of Nonpregnant Women

Abstract

Objective: To compare the prevalence and size of residual niche in the nongravid uterus following Cesarean delivery (CD) with different hysterotomy closure techniques (HCTs).

Methods: Saline infusion sonohysterogram (SIS) was performed in women after one prior CD, documenting the presence or absence of a postoperative niche and measuring its depth, width, length, and residual myometrial thickness. Women were grouped by HCT: Technique A (endometrium-free) and Technique B (routine non-endometrium-free). The primary outcome was the prevalence of a clinically significant niche, defined as a depth of >2 mm. HCT groups were compared using χ² , T-test (ANOVA), and analyzed using logistic regression and two-sided test (P < .05).

Results: Forty-five women had SIS performed, 25 and 20 via Technique A and B, respectively. Technique groups varied by average interval time from CD to SIS (13.6 versus 74.5 months, P = 0.006) but were otherwise similar. Twenty niches were diagnosed, 85% of which were clinically significant, including five following Technique A, nine following Technique B with double-layer closure, and three following Technique B with single-layer (P = .018). The average niche depth was 2.4 mm and 4.9 mm among the two-layer subgroups following Techniques A and B, respectively (P = .005). A clinically significant niche development was six times higher with Technique B when compared to Technique A (OR 6.0, 95% CI 1.6-22.6, P = .008); this significance persisted after controlling for SIS interval on multivariate analysis (OR 4.4, 95% CI 1.1-18.3, P = .04). The average niche depth was 5.7 ± 2.9 mm following Technique B with single-layer.

Conclusion: Hysterotomy closure techniques determine the prevalence of post-Cesarean delivery niche formation and size. Exclusion of the endometrium at uterine closure reduces the development of significant scar defects.

Keywords: cesarean scar defect; cesarean section; endometrium-free closure technique; niche; sonohysterography; uterine closure.