Introduction
Anorectal malformations (ARMs) represent a spectrum of defects with different anatomical and physiological features [1]. Congenital anomalies associated with ARMs may develop in many other organs and systems, e.g. vertebral, cardiovascular, gastrointestinal, neurological, urogenital and skeletal, with their incidence ranging from 30 to 70%. Presence of multiple defects increases both morbidity and overall mortality rate in children with ARMs [2-5]. In consequence, a surgeon dealing with a newborn with an ARM is, in most cases, managing a baby with multiple congenital anomalies, and has to concentrate not only on the gastrointestinal tract, but also look for other defects to confirm or exclude their presence. Most reports in the literature concentrate on genitourinary tract and sacrum defects coexisting with ARM. Although the genitourinary tract and lumbosacral spine are the most frequent sites of associated defects, they rarely influence the mortality rate in this group of patients [6-9].
The aim of this study was to evaluate the incidence of anomalies of different organs and systems in a group of 109 consecutive children with ARMs and to compare their distribution between sexes and high and low ARMs.
Material and methods
Between April 1992 and December 2008, 109 children with ARMs referred to the Polish Mother’s Health Centre (1992-1997) and the University Children’s Hospital No. 4 in Łódź (1998-2008) were personally operated on by the author. Medical records of all patients were reviewed retrospectively and the recorded data included sex, duration of pregnancy, body weight at birth and APGAR score, type of ARM and any associated anomalies.
The type of ARM was determined on the basis of perineal appearance, the result of invertography and ultrasound of the perineum in newborns and distal colostography in children with created colostomy [10]. Anorectal malformation was classified according to Pen~a as either high (supra and translevator), low (infralevator) or complex defect [1]. Therefore, four subgroups of patients were formulated: boys with high ARMs, girls with high ARMs, boys with low ARMs and girls with low ARMs (Table I).
All associated anomalies were classified in ten categories after assembling all cases: urological, vertebral (incl. sacral bone), other skeletal, central nervous system (CNS), tracheoesophageal, cardio-vascular, genital, gastrointestinal, miscellaneous and chromosomal abnormalities.
Lumbosacral spine and genitourinary tract were examined routinely in all patients as the most frequent sites of congenital defects associated with ARMs [6-9]. The evaluation of the sacral bone was based on the value of the sacroiliac ratio (SIR) calculated on the antero-posterior (a-p) radiogram of the pelvis [11]. It was done routinely during cystography, as part of a complex diagnostic examination of the urinary tract performed in every patient. Diagnostics began with US examination, followed by voiding cystography. If any defect was found, i.v. pyelography and renoscintigraphy were performed to evaluate the function of the kidneys and decide upon the type of treatment [12].
Other associated defects were diagnosed according to clinical presentation. Major anomalies were defined as those that have serious medical, surgical, or cosmetic consequences. Their incidence was compared between sexes and subgroups of high and low ARMs.
Statistical analysis consisted of c2 test with Yates and Fisher exact corrections.
Results
Incidence, perinatal data and sex
The approximate incidence of ARMs in the years 1991-97 in the population of Lodz province based on the presented group of patients and data obtained from the other paediatric centre (there are two in Lodz) was 1 : 2295 [13]. Fifteen children died in the neonatal period due to lethal associated anomalies; thus the mortality rate was 13.8%. They were included in the classifications and analysis.
The mean duration of pregnancy was 39.1 hbd, mean birth weight was 3111 γ and mean Apgar score was 8.76. There were no significant differences in the examined parameters between subgroups of low and high ARMs. Fifteen newborns with ARMs who died in the neonatal period had duration of pregnancy significantly shorter (35.5 hbd), mean birth weight significantly lower (2385 g) and Apgar score significantly lower (5.3) than 94 babies who survived (p < 0.001).
In the analysed group of 109 children with ARMs there were 56 boys (51.4%) and 53 girls (48.6%); thus the sex ratio was M : F = 1.05 : 1.
Classification of ARMs according to Pena [1]
Out of 109 children low type malformations were found in 76 children (69.7%) and they were twice as frequent as high defects, observed in 33 children (30.3%). High ARMs occurred almost three times more frequently in boys than in girls (p = 0.006). Conversely, low ARMs prevailed in girls (p = 0.006) (Table I). The most frequent low ARM in boys was imperforate anus without fistula, representing 1/5 of all ARMs found in boys. Perineal fistula and vestibular fistula constituted 3/4 of all ARMs observed in girls. Of high defects, the most frequent was urethral prostatic fistula in boys and persistent cloaca in girls (Table II).
Associated anomalies
Anomalies of other organs and systems found in children with ARMs were categorized in ten groups (Table III).
A total of 158 associated anomalies were found in 72 children (66.1%) with ARMs. The remaining
37 patients (33.9%) had isolated ARM diagnosed. Overall, urinary tract anomalies were observed in 38.5% of patients with ARMs and together with vertebral defects, seen in 33.9% of cases, were the most common associated anomalies in the present series. Primary VUR (n = 14) and renal agenesis (n = 10) prevailed among urinary anomalies, while missing sacral and coccygeal vertebra (n = 22) and hemivertebra (n = 11) occurred most frequently among vertebral defects. Tracheoesophageal anomalies (n = 4, 3.7%), defects classified as miscellaneous (n = 6, 5.5%) and Down’s syndrome (n = 3, 2.8%) were the least often observed malformations associated with ARMs.
Association of additional anomalies with high ARMs was observed two times more often than with low ARMs. Boys with ARMs had significantly higher risk of having coexisting defects than girls with ARMs (p < 10–5). Also, boys with high ARMs had the highest risk of having associated anomalies (p = 0.002), compared with boys with low ARMs and girls with low and high ARMs. On the other hand, subjects with isolated ARMs more often had low ARM (p = 0.04) (Table IV).
Chi-square test was applied to compare data concerning anomalies associated with ARMs between sexes and between high and low ARMs (Table V). Boys with ARMs had significantly higher incidence of coexisting urinary tract, genital, cardiovascular and CNS anomalies. Children with high ARMs had significantly higher incidence of urinary tract, vertebral, genital, cardiovascular and CNS defects. Associated urological, vertebral and CNS anomalies occurred significantly more frequently in boys with high ARMs than in boys with low defects. On the other hand, girls had higher incidence of urinary tract anomalies coexisting with low ARMs and vertebral defects with high ARMs (Table V).
Multiple (two or more) associated anomalies were found in more than half of children with defects coexisting with ARMs (40/72 – 55.5%) (Table VI). Association of urinary and vertebral anomalies was observed most frequently in the examined group.
Following data in the literature I qualified patients to have VATER or VACTERL association if
3 or more of the constituting anomalies were present [14-16].
All components of VATER complex (vertebral defects, anal atresia, tracheoesophageal fistula with oesophageal atresia, and radial and renal anomalies) were found in one instance, four in 2 patients, and three elements in 10 children. VACTERL association (vertebral, anal, cardiac, tracheal, oesophageal, renal, and limb anomalies) was not observed in the presented case series.
Discussion
Anorectal malformations occur with relatively high frequency. The incidence of ARMs estimated by the author was approximately 1 in 2300 live births [13] and was within the incidence range reported by other authors [1, 2, 4, 5]. It is well known that congenital anomalies of multiple organs and systems are associated with ARMs, and that the presence of these additional defects determines and influences morbidity and mortality in this group of patients [2-5]. Anomalies coexisting with ARMs can be categorized as follows: malformation syndromes, malformation associations, malfor-mation sequences, chromosomal abnormalities, and sporadic isolated anomalies.
I observed coexisting congenital anomalies in 66% of children with ARMs in my series, which is within the range of 30% to 70% incidence of associated defects reported in the literature [2, 4, 5, 17, 18]. The male to female ratio in the analyzed group was approximately 1.05 : 1, while that given by other authors ranged from 1.2 : 1 to 1.8 : 1 [2-5].
The regions most frequently affected by additional anomalies in my group of patients were the urinary system, vertebral column and genitals. I observed abnormalities in the urinary system in 38.5% and in genitals in 18.3% of patients with ARMs. Together the incidence of genitourinary anomalies in my case series was 56.8%, compared with the frequency in the literature ranging from 26 to 85% in patients with ARMs [1-3, 5-7, 17, 18]. Because of the high incidence of these associated abnormalities, evaluation of the genitourinary system in patients with ARMs is recommended by many researchers [4, 6, 7, 17-20]. I performed voiding cystourethrogram and ultrasound examination of the kidneys and bladder as a routine procedures in all patients with ARMs.
Vertebral anomalies including sacral bone defects were observed in 34% of the infants in the analyzed case series. The reported incidence of this type of anomaly in patients with ARMs ranges from 7 to 38% [3, 4, 7, 17, 18, 20]. Many authors recommend ultrasonography and radiography in evaluation of the vertebral column, and MRI in cases of abnormal findings on radiographs or ultrasound [4, 7, 19, 20]. In our institution the lumbosacral spine was evaluated on a radiograph performed during the voiding cystography, as part of routine management of patients with ARMs.
Cardiovascular anomalies were observed in 13.7% of babies with ARMs in my case series. Echocardiograms were performed as part of early diagnostics if the presence of cardiac defect was suspected [3, 4, 21]. Central nervous system anomalies were found in 11% of cases. Both severe cardiovascular and CNS anomalies influenced mortality rate in the analyzed group of patients.
The only chromosomal abnormality was trisomy 21, observed by me in three instances and confirmed by karyotypes. The association of Down syndrome with ARMs is well known and has been described in the literature [5, 22].
Among several syndromes described in the literature as being associated with ARMs are the following: Townes-Brocks, Johanson-Blizzard, Pallister-Hall, Currarino, cat’s-eye, Down, Opitz, Zellweger, and FG syndromes [3, 5, 23]. None of these syndromes were observed in the presented group of patients.
VATER association, as the only malformation association, was observed in 13 cases of the examined group of patients. The expression of this association shows phenotypic heterogeneity.
None of my patients had any other malformation association or sequence reported as coexisting with ARMs, i.e. exstrophy of cloaca sequence, sirenomelia sequence, caudal regression sequence, Klippel-Feil sequence, OEIS complex (omphalocele, exstrophy, imperforate anus, spinal defects), and CHARGE (coloboma, hearing deficit, anal atresia, retardation of growth, male genital defects, endocardial cushion defect) association [3, 23].
In conclusion, the results of the performed study revealed that 66% of children with anorectal malformations had additional anomalies in other organs and systems. The most frequent sites of coexisting anomalies were the urogenital system and vertebral column, the lumbosacral segment in particular. High ARMs were more frequent in males and were also more frequently associated with other congenital anomalies than low ARMs. Associated urological, vertebral and CNS anomalies occurred significantly more frequently in boys with high ARMs than in boys with low defects and in girls.
Taking into consideration all of the above, it should be stated that it is necessary to evaluate neonates born with ARMs in search of anomalies of other organs and systems, especially those that are the most frequent sites of anomalies associated with ARMs, i.e. the urogenital, vertebral and cardiovascular systems. It is important because these additional defects are responsible for morbidity and mortality in patients with anorectal malformations.
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