Original articleAssociated malformations in patients with anorectal anomalies
Introduction
Anal atresia is the most frequent congenital anal anomalies; it is a complex condition that can be subdivided into high, intermediate, and low atresia according to the level of termination of the rectum or anal canal in relation to the levator ani muscle. It is often associated with anal fistula, which may be recto-vesical, recto-prostatic, recto-urethral, or perineal (ano-cutaneous) in males, or recto-vaginal, recto-vestibular, or perineal in females. The level of atresia is a key factor that affects surgical prognosis. Atresia above the levator ani muscle is also known as anorectal agenesis; it is associated with a poor prognosis for fecal continence. In atresia below the levator ani, the prognosis is better. Atresia involving the anus, namely imperforate anal membrane and completely covered anus, carries the best prognosis following surgery [3]. The classification into high, intermediate, or low anal anomalies was proposed in 1970 at an international meeting in Melbourne, and is now generally accepted with minor modifications [14]. Anal atresia may be considered to be part of the broader spectrum of anorectal malformations (ARM) that also includes anal stenosis, ectopic anus, congenital anal fistula, and persistence/exstrophy of the cloaca [4]. Anorectal malformations (ARM) are frequently associated with other congenital defects. However, the reported prevalence at birth and the type of associated malformations reported vary considerably among diverse studies, between 20% and 70% [1], [2], [3], [4], [5], [6], [7], [11], [13].
It has also not been established whether ARM are related to specific types of other congenital defects and there are differences in reports concerning which organ system is most often affected by associated malformations. For example, Hassink et al. [7] noted that 16% of the patients with ARM had facial anomalies whereas in the series of Cho et al. [3], 34% of the patients with ARM had also facial anomalies.
Moreover, comparisons between older and more recent studies are difficult because a number of what have formerly been regarded as associated malformations are now recognized to be specific syndromes, associations or sequences. The purpose of this investigation was to assess the prevalence of associated malformations in patients with ARM in a geographically defined population.
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Materials and methods
The malformations for this study came from 334,262 consecutive births of known outcome registered by our registry of congenital anomalies, described previously [15]. The newborns and fetuses of 11 maternity-hospitals were examined from January 1, 1979, to December 31, 2003. The region of investigation was the city of Strasbourg, France (an urban area), and the area defined by the “departement du Bas-Rhin” in which Strasbourg is situated (a rural area). All newborns including live births and
Prevalence of anorectal malformations at birth
The number of children with ARM during the study period was 174 resulting in a prevalence of anorectal malformations at birth of 5.2 per 10,000.The number of cases registered per year varied from 1 in 1994 to 15 in 1992. Related to the number of live births, this gave an annual range of 0.8 to 10.9 per 10,000 live births. Of these 174 patients, 88 (50.6%) were isolated anomalies giving a prevalence of 2.6 per 10,000 births (Table 1). The remaining 86 cases (49.4%) involved one or more
Discussion
Anorectal malformations are not uncommon congenital anomalies. The incidence of ARM was approximately 1 in 2000 births in our patient population. Additional congenital anomalies are often present in patients with ARM, and it is these coexisting anomalies that account for the high morbidity and mortality associated with this condition [3], [7], [12]. We observed additional congenital anomalies in 49.4% of patients affected with ARM in our population. The range incidence of additional anomalies
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