The HysNiche trial: hysteroscopic resection of uterine caesarean scar defect (niche) in patients with abnormal bleeding, a randomised controlled trial

Abstract

Background: A caesarean section (CS) can cause a defect or disruption of the myometrium at the site of the uterine scar, called a niche. In recent years, an association between a niche and postmenstrual spotting after a CS has been demonstrated. Hysteroscopic resection of these niches is thought to reduce spotting and menstrual pain. However, there are no randomised trials assessing the effectiveness of a hysteroscopic niche resection.

Methods/design: We planned a multicentre randomised trial comparing hysteroscopic niche resection to no intervention. We study women with postmenstrual spotting after a CS and a niche with a residual myometrium of at least 3 mm during sonohysterography. After informed consent is obtained, eligible women will be randomly allocated to hysteroscopic resection of the niche or expectant management for 6 months. The primary outcome is the number of days with postmenstrual spotting during one menstrual cycle 6 months after randomisation. Secondary outcomes are menstrual characteristics, menstruation related pain and experienced discomfort due to spotting or menstrual pain, quality of life, patient satisfaction, sexual function, urological symptoms, medical consultations, medication use, complications, lost productivity and medical costs. Measurements will be performed at baseline and at 3 and 6 months after randomisation. A cost-effectiveness analysis will be performed from a societal perspective at 6 months after randomisation.

Discussion: This trial will provide insight in the (cost)effectiveness of hysteroscopic resection of a niche versus expectant management in women who have postmenstrual spotting and a niche with sufficient residual myometrium to perform a hysteroscopic niche resection.

Trial registration: Dutch Trial Register NTR3269 . Registered 1 February 2012. ZonMw Grant number 80-82305-97-12030.

Fig. 1

Sonohysterographic visualisation of a niche. The arrow indicates a disruption of the myometrium in the anterior wall of the uterus over a distance of approximately 15 mm

Fig. 2

Niche surface during hysteroscopic evaluation of proximal part of the niche, several small vessels that easily bleed can be visualised

Fig. 3

Niche measurement during sonohysterography in the sagittal plane (a), transversal plane (b) with the thinnest residual myometrium and niche shape will be registered in both planes (c). a Measuring a niche in the sagittal plane. Schematic drawing demonstrating how to measure a niche in the sagittal plane. The depth of the niche is measured from the usual limit of the uterine cavity until the apex of the niche (1), the residual myometrium from the apex of the niche until the serosa (2). a is an adapted figure of the one that was published by Bij de Vaate et al. 2011 [5]. b Measuring a niche in the transversal plane. Schematic drawing demonstrating how to measure a niche in the transversal plane. The depth of the niche is measured from the usual limit of the uterine cavity until the apex of the niche (1) and the residual myometrium from the apex of the niche until the serosa (2). c Niche shape. Schematic diagram demonstrating classification used to assess niche shape as published by Bij de Vaate et al. 2011: triangle, semicircle, rectangle, circle, droplet and inclusion cysts [5]

Fig. 4

Flowchart. * Questionnaires: Menstruation questionnaire, SF-36 (Short Form-36 [29, 30]), Euro-Qol 5D [31], FSFI (Female Sexual Function Index) [32], menstruation chart [28], costs and consultation diary, HLQ (Health and Labour Questionnaire) [33]

Fig. 5

Schematic diagram of niche characteristics during hysteroscopy

Fig. 6

Resection of the distal part of the niche. Is a modified figure of the one that was published by Gubbini et al. 2008 [18] and v.d. Voet et al. [26]