Niche definition and guidance for detailed niche evaluation

With interest we read the correspondence of Bamberg et al.1 and Scioscia et al.2 about the randomized controlled trial of the first authors concerning the uterine niche after caesarean section (CS).3 They state that at the time of the trial it was not established which technique should be used in the evaluation of a caesarean scar or niche in daily practice and future research. Both authors underline the need for a uniform evaluation of the CS scar establishing an internationally accepted definition of a niche. In their study a niche was defined as an anechogenic area at the site of the uterine scar with a depth of at least 1 mm

A practical guideline for examining a uterine niche using ultrasonography in non-pregnant women: a modified Delphi method amongst European experts

To generate a uniform, internationally recognized guideline for detailed uterine niche evaluation by ultrasonography in non-pregnant women using a modified Delphi method amongst international experts.status: publishe

Sonographic examination of uterine niche in non-pregnant women: a modified Delphi procedure

Objective To generate guidance for detailed uterine niche evaluation by ultrasonography in the non‐pregnant woman, using a modified Delphi procedure amongst European experts. Methods Twenty gynecological experts were approached through their membership of the European Niche Taskforce. All experts were physicians with extensive experience in niche evaluation in clinical practice and/or authors of niche publications. By means of a modified Delphi procedure, relevant items for niche measurement were determined based on the results of a literature search and recommendations of a focus group of six Dutch experts. It was predetermined that at least three Delphi rounds would be performed (two online questionnaires completed by the expert panel and one group meeting). For it to be declared that consensus had been reached, a consensus rate for each item of at least 70% was predefined. Results Fifteen experts participated in the Delphi procedure. Consensus was reached for all 42 items on niche evaluation, including definitions, relevance, method of measurement and tips for visualization of the niche. A niche was defined as an indentation at the site of a Cesarean section with a depth of at least 2 mm. Basic measurements, including niche length and depth, residual and adjacent myometrial thickness in the sagittal plane, and niche width in the transverse plane, were considered to be essential. If present, branches should be reported and additional measurements should be made. The use of gel or saline contrast sonography was preferred over standard transvaginal sonography but was not considered mandatory if intrauterine fluid was present. Variation in pressure generated by the transvaginal probe can facilitate imaging, and Doppler imaging can be used to differentiate between a niche and other uterine abnormalities, but neither was considered mandatory. Conclusion Consensus between niche experts was achieved regarding ultrasonographic niche evaluation. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology