**6.5 Amniotic band syndrome (ABS)**

Amniotic band syndrome can lead to fetal death from umbilical cord strangulation and/or congenital limb deformity or loss, presumed to result from ischemia caused by constriction bands that interfere with vascular perfusion. There is increasing experience with intrauterine release of congenital constrictions and evidence is mounting that this therapy may help save/restore some limb function and morphology. The location of the bands and timing of fetal damage will affect the presentation, severity, and outcome of the condition. For example, pseudosyndactyly or limb amputation can be the results of constriction bands at the extremities, whereas more midline bands can result in craniofacial, thoracic, or abdominal defects, and may be fatal. The etiology of this syndrome is unknown, and theories range from a genetic basis or early disruption of the germinal disc to traumatic disruption of the membranes later in fetal development. Fetoscopic release of amniotic bands using minimally invasive surgery, can help in preservation of life and or limb saving in cases of ABS. The present acceptable functional outcome in 50% of cases is promising, although, clear selection criteria are needed to justify the risk of this in-utero invasive procedure, through increased experience and larger studies on this type of therapy for ABS (**Figure 4**).

In cases of extremity involvement by amniotic band syndrome, the band must be released using fetoscope to save the normal development of the limb and allow for normal limb function. Ultrasound imaging can easily diagnose the problem, showing; distal limb edema and interrupted blood flow by Doppler, with or without visualization of the constricting band. Although, the available reports include small case series, its results suggest that fetuses must have distal arterial limb flow detected by Doppler in order to benefit from intervention. Moreover, data from recent studies reported that fetuses with single limb involvement tend to do better than those with multiple involved limbs. Surprising, the incidence of PROM with this procedure seem to be higher than for other fetoscopic procedures, (reported rates up to 78%). Although, small number of cases were reported in all available studies, and considering the learning curve in this studies, it could also be related to inherent membrane problems in these fetuses [76, 77].
