to those that are complex, difficult to manage, are often associated with other anomalies, and have a poor functional prognosis.
Anorectal malformations are congenital anomalies that occur in approximately 1 in 5000 live births.
Imperforate anus has been a well-known condition since antiquity. For many centuries, physicians, as well as individuals who practiced medicine, created an orifice in the perineum of children with imperforate anus. Those that survived most likely suffered from a type of defect that would now be recognized as "low". Those with a "high" defect did not survive that treatment. Amussat, in 1835 was the first individual who sutured the rectal wall to the skin edges, which could be considered the first anoplasty. During the first 60 years of the 20th century, surgeons performed a perineal operation without a colostomy for the so-called low malformations. High imperforate anus was usually treated with a colostomy performed in the newborn period, followed by an abdomino-perineal pull-through some time later in life, but surgeons lacked objective anatomic guidelines. Unfortunately this left many patients incontinent and was not an appropriate solution to the spectrum of malformations. The surgical approach to repairing these defects changed dramatically in 1980 with the introduction of the posterior sagittal approach, which allowed surgeons to view the anatomy of these defects clearly, to repair them under direct vision, and to learn about the complex anatomic arrangement of the junction of rectum and genitourinary tract [1–6]. It has become the predominant surgical method for anorectal anomalies. In cases when the rectum or the vagina are very high and an abdominal approach as well is needed, laparoscopy can be used in combination with the posterior sagittal approach.
Comparing the results of reported series has always been a problem with anorectal malformations because different surgeons use different terminology when referring to types of imperforate anus. The clearest fact is that there is a spectrum of defects, so every attempt to classify them is arbitrary and somewhat inaccurate. Consequently, the traditional classification of "high", "intermediate", and "low" defects renders the results dubious. The classification presented here attempts to group together defects that have common diagnostic, therapeutic, and prognostic features (Tables 1 and 2).
The posterior approach and direct visualization of the anatomy have allowed us to learn about important features. For instance, rectovaginal fistula are almost nonexistent, in retrospect it seems that most of the previously reported "rectovaginal fistula" cases were misdiagnosed cloacas. This assertion is supported by the authors' experience of cloaca reoperations where it has been found that most patients who were originally operated on by a surgeon who classified the defect as a "rectovaginal fistula" had only the rectal component of the cloaca repaired and had been left with a persistent urogenital sinus. Such patients have become categorized as instances of "rectovaginal fistula" and the true diagnosis of cloaca has become evident only many years later. In addition, many patients had undergone a abdominoperineal pull-through at another institution to repair a "rectovaginal fistula," and years later had been referred because of fecal incontinence. When these girls were examined, the little pouch of what used to be the rectum was found opening into the vestibule, indicating that these patients were been born with a rectovestibular fistula. The cloaca itself represents a spectrum and certainly defies the classification "high", "intermediate", and "low".
Also included in the "high" category in male patients were those with completely different defects requiring differing treatments and carrying a different prognosis (e.g., rectourethral fistula and rectobladderneck fistula). A rectourethral fistula can be treated without an abdominal approach, but a rectobladderneck fistula always requires the abdomen to be entered either with laparoscopy or laparotomy. The