Ml. Martinez-frias et al., Exstrophy of the cloaca and exstrophy of the bladder: Two different expressions of a primary developmental field defect, AM J MED G, 99(4), 2001, pp. 261-269
Exstrophy of the bladder (EB) and exstrophy of the cloaca (EC) are generall
y recognizable as distinct clinical entities. In patients with EB, the post
erior bladder wall is exposed through a midline defect of the abdomen, The
umbilicus is inferiorly displaced and located close to the superior margin
of the exstrophic bladder. Genital abnormalities are common in boys and gir
ls who may present epispadias and a small, split phallus or a split clitori
s, a bifid uterus, and a duplicate or exstrophic vagina. In contrast to cla
ssic EB, EC is commonly associated with omphalocele, spinal defects, and in
completely formed external genitalia and is always associated with imperfor
ate anus. Some authors state that EC and EB constitute two distinct disorde
rs, but others consider them part of a "continuum," representing different
levels of severity within the same spectrum. The use of the acronym OEIS to
refer to the combination of omphalocele, exstrophy, imperforate anus, and
spinal defects, in our opinion, has not helped to clarify the clinical defi
nition, pathogenesis, or cause of this multiple congenital anomaly (MCA) pa
ttern, mostly because the term makes no distinction between EC or EB, Here
we present the epidemiological analysis of a group of characteristics in in
fants with EC and infants with EB to determine if they constitute two diffe
rent entities. We also analyze if the different combinations of omphalocele
, imperforate anus, and spinal defects are more frequent in infants with EC
than in infants with MCA patterns other than EC and EB. The prevalence in
our data for EC was 1:200,233 live births and 1:35,597 for EB. The clinical
analysis indicated that the study defects (omphalocele, spine defects, spi
na bifida, and imperforate anus) tend to occur together in the same child w
ith a higher frequency if the child has the EC defect than in infants with
MCA patterns that did not include EC or EB, Our findings of low birth weigh
t, twinning, single umbilical artery, and preferentially associated malform
ations suggest that EC is the result of damage occurring very early in deve
lopment and that EC and EB are two different expressions of a primary polyt
opic developmental field defect. (C) 2001 Wiley-Liss, Inc.