Constrictive amniotic bands, amniotic adhesions, and limb‐body wall complex: Discrete disruption sequences with pathogenetic overlap

Abstract

In a fetopathologic evaluation of 18 cases with amniotic bands, we discerned 3 types of lesions: (1) constrictive tissue bands, (2) amniotic adhesions, and (3) more complex anomaly patterns, designated as limb-body wall complex (LBWC). Constrictive bands are caused by primary amnion rupture with subsequent entanglement of fetal parts (mostly limbs) by shriveled amniotic strands. Adhesive bands are the result of a broad fusion between disrupted fetal parts (mostly cephalic) and an intact amniotic membrane. Most of the craniofacial defects (encephaloceles and/or facial clefts) occurring in these fetuses are not caused by constrictive amniotic bands, but are the result of a vascular disruption sequence with or without cephalo-amniotic adhesion. Our observations confirm the fact that amnion rupture is not a conditio sine qua non for the development of LBWC. However, LBWC is often complicated by rupture of the unsupported amnion with ensuing formation of constrictive bands. We think that the concept that considers the 3 lesions in question as a single pathogenetic entity is erroneous and will inevitably lead to a never-ending debate between followers of the 2 prevailing theories. In our view, the theories of Streeter and Torpin are not mutually exclusive but rather apply to different types of lesions. The recognition of constrictive amniotic bands, amniotic adhesions, and LBWC as discrete but often combined disruption sequences with important pathogenetic overlap may resolve many dilemmas in interpretation when a fetus exhibits classical constrictive bands beside more severe defects.

Limb–body wall defect. Is there a defensible hypothesis and can it explain all the associated anomalies?

“…Other authors have disagreed [e.g., Pagon et al, 1979;Russo and Vecchione, 1996;Craven et al, 1997;Luehr et al, 2002]. Similarly the idea that a singular pathogenetic mechanism can explain the spectrum of associated findings has been questioned [e.g., Luebke et al, 1990;Moerman et al, 1992], and furthermore there has been concern that such lumping may impede discovery of the underlying pathogenesis [Russo et al, 1993;Craven et al, 1997]. Even the definition of LBWD that allows inclusion of cases that have craniofacial and limb defects but lack an abdominal wall defect, or have a body wall and craniofacial malformation but no limb anomaly is debated [Martinez-Frias, 1997].…”

“…This hypothesis has been accepted as reasonable by some subsequent authors [Colpaert et al, 2000;Pumberger et al, 2001], while others have rejected the notion. Moerman et al [1992] claim it to be unlikely because it would be expected to be associated with familial recurrence, but they ignore the possibility of new dominant mutations accounting for this lethal malformation, and there is at least one reported recurrence of LBWD [Luehr et al, 2002].…”

Amniotic Constriction Band: A Multidisciplinary Assessment of Etiology and Clinical Presentation

“…In another review, fifty-four subjects with limb and body-wall defects and a variety of internal organ anomalies were reported as having lower-limb lesions (amelia in seven subjects; limb hypoplasia in five; rotational abnormality in three; split foot in two; and a complex defect in one), but no upper-extremity abnormalities were reported 26 . On the basis of a series of eighteen fetuses with amniotic constriction band, twelve of whom were also diagnosed with limb and body-wall defects 27 , the authors noted that the nine amputations in that series were not typical of amniotic constriction band (one amputation involved an absent radius and several involved ''rudimentary'' arms), and they concluded that amniotic constriction band and limb and body-wall defects were likely from separate etiologies with a phenotype overlap.…”

Síndrome de bridas amnióticas, a propósito de 3 casos clínicos

“…Una evaluación fetopatológica de 18 casos con SBA, por Moerman y col 7 , discernieron tres tipos de lesiones: bandas constrictivas de tejido, adhesiones amnióticas y patrones más complejos de la anomalía designados como complejo de pared cuerpo-miembro. Las bandas constrictivas son causadas por la RPA, donde se compromete subsecuentemente las partes fetales y sobre todo las extremidades.…”