Ankh-Habashy sign, a novel sonographic marker for isthmocele using 3D-TVUS surface mode: an observational study and review of literature

El-Habashy Ahmed

Objectives: The isthmocele or cesarean scar defect (CSD) is an evolving iatrogenic long-term complication of cesarean section (CS). It represents an incomplete healing of the CS scar that lead to the presence of a wedge-shaped anechoic area of myometrial discontinuity at the CS site with at least 2 mm depth. The aim of our study is to evaluate the shape of the uterus in the coronal plane in cases who has isthmocele using the surface mode of the three-dimensional transvaginal ultrasound (3D-TVUS). To our best knowledge this is the first study to describe the coronal sonomorphology of the CSD using 3D-TVUS. Methods: This retrospective observational study that enrolled 84 cases over a period of 2 years (from august 2017- august 2019) from a single tertiary center. All are in the reproductive age window: 18- 42 years old. All had complained AUB in the form of postmenstrual spotting with or without chronic pelvic pain (CPP) and/or secondary infertility. All cases are scanned postmenstrually by the same sonographer using TVUS. Isthmocele is defined as a wedge-shaped hypoechoic area of myometrial discontinuity at the CS site in the sagittal plane of the uterus with a depth of ≥ 2mm. We measured the residual myometrial thickness (RMT) and the adjacent myometrial thickness (AMT) in all cases. After obtaining an optimal 2D sagittal uterine view, the 3D box was set to include the whole uterus from the fundal serosa till the external os. Our target was to produce a panoramic volumetric image of the uterus that include the cavity above, the cervical canal below and the isthmus in between. Results: We noticed a lateral bulge or shadow at the level of the isthmus in 82.1% of cases of isthmocele. The lateral bulge produced by the isthmocele simulates the “ankh”; an ancient Egyptian hieroglyphic symbol of life. We call this sonomorphology the “Ankh-Habashy sign”. The mean age of patients was 29.5 years. The mean number of previous CS was 2. The mean interval from the last CS was 3 years. All cases were complained of AUB in the form of postmenstrual spotting. 42.9% of cases had an associated secondary infertility. 66.7% of cases had an associated chronic pelvic pain (CPP). 56% of the cases were RVF uterus, 26% were erect uterus and 19% were AVF uterus. Conclusion: Lateral bulge at the level of the isthmus in the coronal panoramic view of the uterus using 3D-TVUS-surface mode; “the Ankh-Habashy sign” is a reproducible sonographic sign that is present in most cases of isthmocele.