Normalization of Subendometrial Peristalsis in Women with a Large Uterine Niche Following Laparoscopic Niche Repair: A Prospective Cohort Study

Objective: To study the impact of laparoscopic niche repair on subendometrial peristalsis in women with a large niche.

Methods: A explorative prospective cohort study that included women with a large niche (residual myometrium ≤ 3 mm), actual wish to conceive who were scheduled for laparoscopic niche repair. To analyse the effect of a laparoscopic niche repair on the uterine anatomy and subendometrial peristalsis, all participants underwent a 4-5 min transvaginal ultrasound before surgery and three months post-surgery during the mid-luteal phase of the menstrual cycle. Subendometrial peristalsis was evaluated by strain analysis using a dedicated two-dimensional optical flow speckle tracking method. The following features were extracted from the strain signals: frequency, amplitude, velocity, coordination and direction of coordination.

Results: Post-surgery, the mean niche volume significantly decreased, with a mean reduction of 963.9 mm (95 % CI 382.0-1545.7). Additionally, the residual myometrium thickness increased significantly, with a mean difference of 5.8 mm (95 % CI 6.8 to 4.7). Of the subendometrial peristalsis, a significant improvement of the frequency was observed. Although amplitude, velocity, and direction of the contractions shifted towards normal values, these changes did not reach statistical significance in this pilot study. The improvements in individual peristaltic characteristics were closely associated with reductions in niche volume and enlargement of residual myometrium.

Conclusion: Subendometrial peristalsis is disturbed in women with a large niche. Individual contraction parameters such as velocity, amplitude and frequency decreased following laparoscopic niche repair which might be favourable for fertility purposes. These changes were associated with a reduction in niche volume and enlargement of the residual myometrium and warrant further validation in a larger cohort study.