Detection of Obstetric Anal Sphincter Injuries With ONIRY Device

The main purpose of the study is to confirm the clinical performance and safety of impedance spectroscopy using the ONIRY device for the detection of anal sphincter injuries arising from vaginal deliveries. The whole study is divided into 2 parts. Part I is a clinical trial; after completion of Part I, an analytical classification model will be established (during Part II) based on data from pilot studies and Part I of the study. It will be then built into the ONIRY Meter as a machine-learning-based interpretation module; proposed for ultimate marketing authorisation. Part I of the study will be prospective, multicentre, international. The study group comprises 150 primiparous or multiparous women up to 8 weeks after the vaginal (spontaneous or assisted) delivery of singleton, live foetus, in any presentation, in gestational week 34 or more. The timeline for each subject in the study will be up to 5 weeks and will include 3 visits (V1-V3). After obtaining written consent, at the first study visit (V1) each patient will undergo a general physical examination, proctological and gynaecological examination, ECG recording, 3-D EUS (endoanal ultrasound, used as a reference and for the study group allocation) and once V1 visit is conducted 3 or more days after delivery Wexner score will be used to assess the clinical symptoms of faecal incontinence. Based on the physical proctological examination and EUS at the V1 visit, all participants will be divided into 3 groups: A, B, C. Group A - subjects with no perineal tear signs, Group B - subjects with the presence of perineal skin injury or perineum injury involving crotch muscles but not involving anal sphincters (grade 1 or 2 per OASIS classification) and Group C - subjects with the presence of perineal injury involving anal sphincters (damage of the external anal sphincter thickness, damage to both the external and internal anal sphincters, or damage to the perineum, anal sphincteric complex and anal epithelium; grade 3-4). On the visit V2 performed on the same day as V1 or scheduled up to 7 days after the V1, after the final verification of inclusion/exclusion criteria, blood samples for laboratory tests and stool samples for calprotectin concentration assessment will be collected, ONIRY recording will be made, 10 minutes after the end of the impedance measurement 12-lead ECG recording will also be performed in each patient. On the third visit (V3) 1-28 days after visit V2, high-resolution Anorectal Manometry will be conducted. No control group is planned. However, study participants will be controls for themselves (test and reference diagnostic methods will be applied and evaluated in each subject). In Part I of the study, the ONIRY system will provide only preliminary interpretations of the impedance measurements based on models established from the data collected during Pilot Studies No. 1/1/2018 (NCT03769792) and No. 2/1/2019 (NCT04181840). The web-based app will be used to provide the interpretations.