This review provides a description of the most common congenital intestinal anomalies and neonatal diseases which require paediatric surgery. The article gives a description of pathological mechanisms, classifications, antenatal and post-partum diagnosis, preoperative management, surgical treatments, post-operative care and complications of oesophageal stenosis and atresia, duodenal stenosis and atresia, interruption of the continuity of the small bowel and the imperforated anus.
Atresia is defined as a complete occlusion of the intestinal lumen, whereas stenosis shows a partial occlusion with incomplete obstruction. As both of these intestinal malformations may lead to a life-threatening condition of the neonate, quick decision-making and therapy is required. As a result of improvements in recent decades in prenatal and postnatal diagnosis, surgical materials and techniques, raising surgical expertise and advances in neonatal intensive care, neonatal anaesthesia, ventilatory and nutritional support and antibiotic therapies, the survival rate of patients with intestinal atresias or stenosis has improved remarkably (90–95%).1
Oesophageal atresia (OA) in combination with or without a tracheo-oesophageal fistula (TOF) is the most common congenital interruption of the continuity of the oesophagus with an overall incidence of one in every 2500–3500 live births.2,3 Mortality is limited mainly to patients with co-existing severe life-threatening anomalies.4 Survival rate increases up to 98% depending on the evidence of associated cardiac malformations and the gestational age.
The pathological mechanism leading to OA with or without TOF is unknown. The trachea, oesophagus and lungs are foregut-derived structures. During the fourth week of embryonic life the foregut divides into a ventral respiratory part and a dorsal oesophageal part. The underlying mechanism of separation is not known.
Oesophageal atresia with or without TOF is thought to be a multifactorial complex disease, with the involvement of genetic and environmental factors. In 6–10% of patients a defined genetic syndrome can be diagnosed, leaving 90% of unknown origin.5 OA is two to three times more common in twins.
Vogt published the first classification in 19296 which was modified by Gross in 1953.7 These two classifications are still valid. They are determined by the location of the atresia and the presence of a fistula to the trachea (Table 1).
|OA||Proximal + distal||Distal||Proximal||Proximal||–|
|TOF||–||Proximal||Proximal + distal||Distal||H-type|
Vogt II (Gross A) occurs in 7% of patients with OA. The proximal as well as the distal oesophagus end blindly. As the dilated proximal part usually ends at the level of the second vertebra and the lower part very often close to the diaphragm, the distance between the two ends could show a long gap, which might complicate the operative reconstruction.
Vogt III (Gross B) shows a proximal TOF, which originates 1–2-cm proximal from the lowest margin of the proximal pouch.
Vogt IIIa (Gross D) is very rare: < 1%. Both proximal and distal blind-ending oesophagus have a TOF, which might lead to wrong diagnosis of a Type IIIB by not recognizing the proximal TOF.
Vogt IIIb (Gross C) is the most common type with an incidence of 85%. It shows a proximal-dilated oesophagus, which ends blindly at the level of approximately the third or fourth thoracic vertebra. The distal segment enters the dorsal part of the trachea close to the carina. The distance between the two parts of the oesophagus can be overlapping or show a long gap.
Vogt IV (Gross E), so-called H-type fistula, is represented by an oesophagus with correct passage and a fistula in the lower cervical region.
Unfortunately, there is no ideal prenatal diagnostic method for OA. Routine prenatal diagnosis is mainly performed through ultrasonography, which often does not show the existence of OA. Indirect signs, such as polyhydramnios and the sonographic evidence of other prenatally diagnosed malformations, may lead to further radiological diagnosis using magnetic resonance imaging (MRI). Post-partum hypersalivation is the first clinical sign.
During prenatal routine ultrasonography scanning, OA can be first suspected between the 16th and 20th week of gestation by the evidence of two non-specific criteria: the absence of a gastric bubble (sensitivity 42%) and evidence of polyhydramnios (sensitivity 1%).8 The combination of both gives a 56% probability of the existence of OA.
A very rare observation is the ‘upper pouch sign’ – a dilatation of the blind fundus of the upper atretic oesophageal segment, which might be visible by ultrasonography during fetal deglutition at the 32nd gestational week carried out by very experienced doctors.8
Complementary to ultrasound, diagnostic antenatal MRI can be performed if OA is suspected. The intrathoracic portions of the oesophagus are visualized and the type of atresia may be suspected.9 This gives the possibility of planning delivery and post-natal care.
In newborns born with OA an excessive salivation due to the impossibility of swallowing is noticed. Respiratory problems and recurrent attacks of suffocation are conspicuous in these infants, and it is impossible to pass a stiff orogastric tube (10–12F) more than 11–12 cm from the alveolar ridge.10 At this point, a spring stop becomes obvious. Attention should be paid to the fact that soft tubes may curl up in the proximal pouch or pass through the trachea and the fistula to the stomach and give a misleading picture of a regular oesophageal passage.
Radiodiagnostically, an X-ray of thorax and abdomen shows the tip of the catheter at the level of T2–4. By insufflating air or water-soluble contrast medium through the tube, it might be possible to visualize the blind-ending upper pouch. Investigators have to be aware of the risk of aspiration. Additionally, the observation of gas in the intestine indicates the presence of a distal TOF (Figure 1a and b).
Tracheobronchoscopy might show the number and location of the TOF.11 An occlusion of the fistula by a balloon helps to avoid gastric distension with the risk of perforation while on mechanical ventilation. Additionally, it blocks gastro-oesophageal-tracheal reflux, which causes severe aspiration and consecutive pneumonia.
More than 50% of patients with OA have associated anomalies and so additional post-natal physical examination and radiological investigations are obligatory.12
Cardiovascular malformations are diagnosed in about one-third of OA patients by performing a post-natal echocardiography [e.g. ventricular septal defect (VSD), tetralogy of Fallot or right aortic arch].
Anorectal malformations are seen in 14%, either isolated or part of VATER or VACTERL complex (see below).
Genitourinary tract malformations are seen in 14%, including malformations of the kidney, bladder and urethra.
Gastrointestinal malformations are seen in 13% including various types of atresia or stenosis of the duodenum, the jejunum, the ileum or the colon.
Various associations, which include OA, should be mentioned:
VATER – a combination of vertebral, anorectal, tracheo-oesophageal and renal abnormalities.
VACTERL – additional cardiac and limb abnormalities.
CHARGE – a combination of coloboma, heart defects, choanal atresia, retarded growth and development, genital hypoplasia and ear deformities.
Potter syndrome has a high mortality due to bilateral renal agenesis, pulmonary hypoplasia and a typical dysmorphic facies.
Trisomy 13, 14 or 18.
The operative correction of OA is an emergency procedure for infants with a TOF and respiratory problems requiring ventilation. Ventilation gas passes the fistula into the stomach and might cause gastric distension or rupture.13 Additionally, continuous gastro-oesophageal–tracheal reflux causes severe aspiration, consecutive pneumonia and respiratory problems.
The first aim of therapy is the stabilisation of the respiratory situation. Endotracheal intubation should be avoided in patients with TOF to prevent gastric gas insufflation during ventilation, which carriers the risk of gastric distension and perforation. If the fistula is proximal to the carina level it might be possible to block it with the endotracheal tube.
A double-lumen catheter (e.g. Replogle catheter no.10 Fr gauge) under continuous suction is placed in the upper pouch to avoid aspiration. The infant should be placed in a semi-prone position to reduce the risk of gastro-oesophageal reflux and aspiration of gastric fluid through the distal TOF. Owing to the risk of pneumonia antibiotic prophylaxis is indicated.
As there is still no ideal replacement for the oesophagus, the first priority is to close the TOF and to reconstruct the oesophagus with primary anatomoses of the blind ends, as long as the gap is not too wide, which means less than two vertebrae.
Operative correction of OA with TOF is performed under general anaesthesia using low ventilatory pressure. Before starting surgery, intraoperative oesophagoscopy and tracheoscopy are performed to localize the fistula(s). Then a right posterolateral thoracotomy is performed to open the thorax through the fourth or fifth intercostal space. If a right aortic arch is known, a left-sided posterolateral thoracotomy is used. Carefully, the parietal pleura is dissected from the chest wall superiorly, inferiorly and dorsally to perform an extrapleural approach to the mediastinum. After ligation of the azygos vein, usually the vagus nerve can be identified which courses over the anterior wall of the distal oesophagus.
First, the distal oesophagus is mobilized circumferentially and then divided from the trachea. The tracheal opening of the fistula is closed with interrupted non-absorbable sutures. By filling the thorax with saline and under manual ventilation the tightness of the fistula closure can be tested. In case air bubbles appear, the leakage has to be resutured. The identification of the proximal oesophageal pouch is easier because the orogastric tube is palpable. With the help of traction sutures, the proximal oesophagus is eventually mobilized up to the upper thoracic inlet to facilitate a tension-free anastomosis. Care must be taken not to miss a possible proximal TOF or not to accidentally injure the dorsal wall of the trachea. If the gap between the pouches is too wide, a short segment of the distal oesophagus can also be mobilized towards the diaphragm; the risk of ischaemia as a result has to be recognized.
After opening the upper pouch and trimming the distal part, an end-to-end anastomosis is performed using interrupted monofilament absorbable full-thickness sutures (Figure 2). A transanastomotic nasogastric tube acts as a stent, enables gastric decompression and gives the possibility of early enteral feeding. It has to be retained on the nose by sutures or tapes to avoid dislocation and lesion of the oesophageal anastomosis. Finally, the thoracotomy is closed. An extrapleural or a thoracic drainage without suction in case of injured pleura is performed.
Some paediatric institutions perform this procedure thoracoscopically, but this requires extensive experience in paediatric thoracoscopic surgery. The outcomes are comparable with the open procedures.14,15
If the gap exceeds more than two vertebrae, delayed primary repair should be undertaken after a period of about 12 weeks. As the oesophagus shows spontaneous growth in this time, the gap gradually narrows. During this period, continuous suction to the upper pouch and enteral feeding after performing a gastrostomy has to be performed.
If the gap distance is more than six vertebrae the Foker technique can be applied.16 By the use of external traction sutures the oesophageal stumps can be narrowed within 6–10 days and primary anastomosis can be successfully performed.
In unsuccessful trials of primary anastomosis, colonic interposition,17 reverse or antegrade gastric tube interposition,18 gastric transposition or free jejunal graft9 interposition can be performed.20
To reduce anastomotic tension it is advisable that the patient is electively paralysed and mechanically ventilated for 5 to 7 days postoperatively,21 which requires admission to a neonatal intensive care unit (ICU). There, haemodynamic, respiratory and metabolic adjustments are made accordingly. Antibiotic coverage that was started intraoperatively has to be continued and adjusted if necessary. Anti-reflux medication with histamine 2 (H2) receptor blockade should be started. Feeding through an intraoperatively inserted transanastomotic tube can be started with small amounts of clear liquid on the third post-operative day if peristalsis is positive.22 After 12–14 days a water-soluble-contrast study can be carried out to show the integrity of the anastomosis. Oral feeding can be started if the child is able to swallow saliva.
Anastomotic leakage occurs in 15–20% within the early post-operative period.23 Minor anastomotic leaks seal spontaneously in a few days. In the case of a big leakage saliva might be drained through the thoracic tube. First-line therapy is drainage, nothing by mouth (NPO) and intravenous antibiotic therapy. If closure cannot be achieved, surgical revision is indicated. If the primary surgical procedure was performed transpleurally an empyema may develop, which requires quick therapy. In the case of complete disrupture, cervical oesophagostomy and closure of the distal oesophagus are performed.
Leaks at the fistula closure site lead to life-threatening tension pneumothorax and require drain placement or emergency thoracotomy with the intention of repairing the suture at the fistula.
Anastomotic stricture occurs in 30–40% of all patients, mostly as a sequence of sealed anastomotic leakage or gastro-oesophageal reflux. In most of these cases singular to recurrent endoscopic dilatations with either semi-rigid bougies or balloon dilatation under fluoroscopic control is successful.24 Stricture resection is rarely performed.
Recurrent TOF (5–14%) is suspected if the child shows recurrent respiratory infections, and cyanotic episodes during feeding.25 Diagnosis is performed by a pull-back oesophagography using a water-soluble contrast medium, which becomes visible in the tracheobronchial system. Bronchoscopy and oesophagoscopy can provide additional information about localization and size of the fistula. Only a few patients show spontaneous closure of the fistula under intravenous antibiotic therapy and NPO; most patients require surgical repair.
Gastro-oesophageal reflux (GER) is a very common late complication (40–65%). The patients suffer acute or chronic respiratory problems, regurgitation, vomiting and growth failure. Prophylactic therapy consists of antireflux medication with H2 receptor blockade, adequate positioning and dietary modification.26 Surgical treatment (e.g. Nissen fundoplication) should be avoided as the recurrence rate is high (> 40%).
Oesophageal dysmotility in the distal oesophagus (75 100%) is the most common late complication. Some patients suffer from recurrent food bolus obstructions even though there is no stricture evident. They must be forced to chew the food properly and to drink fluids at the same time. Oesophageal dysmotility is considered the main cause of GER.
Tracheomalacia (10%) is a congenital deficiency in cartilage in the tracheal rings and a lengthening of the transverse muscle leading to an expiratory stridor, recurrent pneumonias or asthma attacks, which can sometimes even be life-threatening. After bronchoscopic diagnosis, rapid operative aortosternopexy is necessary.27
Recurrent respiratory infections are the result of the above-mentioned complications. Most of the affected children suffer from daily coughing, recurrent bronchitis or pneumonias.28
|Group I||BW > 1500 g||NO major cardiac anomaly*||98% survival|
|Group II||BW < 1500 g||OR major cardiac anomaly*||82% survival|
|Group III||BW < 1500 g||PLUS major cardiac anomaly*||50% survival|
* Cyanotic or non-cyanotic congenital heart disease that requires medical or surgical treatment.
Most morbidities occur as a result of the associated malformations and the post-operative complications.
Duodenal atresia and stenosis
The incidence of duodenal atresia (DA) and stenosis is one in every 5000–10,000 live births. Males are affected more commonly than females.31 In comparison to distal small bowel atresia, associated malformations are more common in these instances.32 Prenatal diagnostic ultrasound gives the possibility of better operative planning. The definitive management of patients with duodenal obstruction is surgical correction.
Duodenal atresia and stenosis are thought to be the result of a failure of recanalization of the embryonic duodenum, which becomes solid as a result of early epithelial proliferation at 8–10 weeks' gestation. Annular pancreas results when the ventral pancreatic bud does not rotate behind the duodenum, which leads to a non-distensible ring of pancreatic tissue fully surrounding the pars descendens of the duodenum. As the duodenal, pancreatic and biliary development take place at the same stage of embryology it is quite obvious that annular pancreas frequently co-exists with intrinsic duodenal anomalies and anomalies of the pancreaticobiliary ductal system.33
|Type I: Duodenum with intraluminal web (‘windsock shape’ – blue line)|
|Type II: Fibrotic cord between blind ending dilated duodenum and proximal jejunum|
|Type III: Complete separation of the blind ending dilated duodenum and proximal jejunum|
Type I is the most common type of DA (92%). It represents a mucosal and submucosal intraluminal web. This membrane can be elongated in the shape of a ‘windsock’. The site of origin of the membrane is proximal to the level of obstruction. The ampulla is located close to the medial wall of the web. The proximal duodenal pouch and stomach are dilated and hypertrophied; the bowel distal of the obstruction is narrow. Sometimes the web contains a small aperture, which results in an incomplete obstruction. In 85% of patients, the obstruction is distal to the ampulla of Vater.
Type II (1%) shows a short fibrotic cord connecting the two atretic duodenal pouches.
Type III (7%) presents with a complete separation of the atretic segments. Most of the biliary duct anomalies associated with duodenal atresia are observed in type III defects.35
Extrinsic obstruction can be caused by malrotation with Ladd bands or other congenital bands not associated with malrotation,36 preduodenal portal vein, gastroduodenal duplications, cysts or pseudocysts of the pancreas and biliary tree. Also, an annular pancreas (8–20% of neonatal duodenal obstructions) may cause duodenal atresia and is commonly associated with an intrinsic cause of DA.33
Modern ultrasonography allows quite reliable prenatal diagnosis of DAs, which allows the planning of the delivery at a perinatal centre with paediatric surgery care. Clear clinical symptoms of obstruction and the typical radiodiagnostic finding of a ‘double bubble’ lead to the diagnosis. However, associated malformations have to be screened out.
In prenatal routine ultrasound, DA can be suspected at 18–20 weeks' gestation in 32–57% of patients.37 Scanning in the third trimester is more reliable. The typical ‘double-bubble sign’ can be seen representing the dilated stomach and proximal duodenum filled with amniotic fluid. If a DA is suspected, obligatory scanning of associated anomalies has to be performed as well as karyotype analysis. In 32–59% of cases, a polyhydramnios is evident.
The typical symptom (38%) of post-ampullary DA is bilious vomiting within 24 hours after birth.38 Non-bilious vomiting occurs when the obstruction is proximal to the ampulla of vater (15%). Typical of DA is the non-distended abdomen but slightly prominent gastric region. Meconium passage is usually normal. A hypokalaemic/hypochloraemic metabolic alkalosis with paradoxical aciduria develops without adequate intravenous hydration. Plain abdominal radiographs show the classic ‘double-bubble sign’ representing the gas collections or air-fluid levels in the dilated stomach and proximal duodenal bulb (Figure 3). Missing bowel gas beyond the double bubble is a sign of total occlusion or interruption of the duodenum. Contrast studies are not necessary as air makes an excellent contrast agent. A fenestrated duodenal web with incomplete obstruction may not be noted at birth but can be seen later in childhood with recurrent vomiting.
Scanning of associated malformations has to be performed post partum. Duodenal obstruction is associated with other congenital anomalies in 38–55% of patients.39 23–34% of cases are associated with isolated congenital cardiac defects that have to be diagnosed prior to surgical repair. Approximately 30% of cases are associated with Down syndrome. Oesophageal atresia may be present in 7–12% of patients. Other gastrointestinal anomalies include malrotation (20%), anterior portal vein, second distal web, anorectal anomalies (3–5%), intestinal atresias (4–6%), cloacal anomalies and renal tract anomalies. Duodenal atresia often is associated with prematurity and low birthweight.40
Duodenal atresia and stenosis have to be treated surgically. The preferred method is a duodenoduodenostomy to bypass the obstruction. A duodenojejunostomy has a higher risk of long-term complications such as blind-loop syndrome. Special attention should be given to cardiac and pulmonary function and to metabolic situation before starting duodenal repair.
Recurrent vomiting requires the insertion of an orogastric/nasogastric tube to decompress the stomach. Recurrent vomiting of the newborn leads to dehydration, changes in serum electrolytes, hypokalaemia and hypochloraemic metabolic alkalosis, and weight loss. Serum parameters are monitored and have to be replaced by intravenous fluids to stabilize the metabolic and haemodynamic situation preoperatively.
With the patient under general anaesthesia and in a supine position, a right-sided transverse supraumbilical incision is performed and at first the intestine should be examined for further anomalies, for example malrotation. The duodenum is then mobilized by the Kocher manoeuvre41 to provide exposure to all portions of the duodenum. The obstruction is localized at the level of the dilated proximal segment and the distal unused bowel. If a windsock web is present a discrete detentation at the proximal pouch might be observed. The web can be excised after proximal duodenostomy. Care must be taken to avoid injuring the ampulla of Vater, which is located close to the medial wall of the web. It can easily be identified by putting pressure on the gall bladder, releasing bile in the region of the ampulla. In any case, a tube has to be passed distally to exclude a distal second web (1–3%) or atresia.
In case of annular pancreas, where the level of obstruction is beneath the gland, or type II and type III duodenal atresias, a side-to-side duodenoduodenostomy to bypass the atresia or stenosis is the procedure of choice. A proximal transverse and distal longitudinal duodenostomy is performed. Then the single-layer transverse-longitudinal diamond-shaped anastomosis42,43 is performed using interrupted absorbable sutures. (Figures 4a–c) A soft trans-anastomotic feeding tube can be placed. The direct duodenoduodenostomy is supposed to result in an earlier recovery of anastomotic function in comparison with duodenojejunostomy.44 If the duodenum is extremely dilated, a tapering duodenoplasty should be performed additionally. An abdominal drain is situated close to the anastomosis.
If the duodenal obstruction is due to malrotation with peritoneal Ladd bands, they have to be divided; an additional appendectomy should be performed and the caoecum and colon should be positioned to the left abdominal side.
All described surgical procedures can be carried out laparoscopically but require advanced laparoscopic skills.45
Post-operative monitoring is performed on a neonatal ICU where haemodynamic, respiratory and metabolic adjustments are made accordingly. Antibiotic coverage started intraoperatively has to be continued. The children should be on total parenteral nutrition (TPN) until the bowel shows peristaltic movements and stools have passed (7–10 days). Gastric drainage by orogastric tube should be < 1 ml/kg/hour and clear. Owing to prematurity or the associated malformations, this period can take longer so that a central venous line (Broviac® catheter) might be necessary. Feeding through the feeding tube or orally should be started slowly with clear fluids when peristalsis is positive and meconium has passed.
Early surgical complications (14–18%)39 are anastomotic leaks at the level of the anastomosis, functional obstructions, adhesions and nondetected second web.
Megaduodenum with duodenal dysmotility leading to duodenogastric reflux is a late complication associated with poor weight gain, frequent vomiting and abdominal pain. It requires late tapering.46
Gastro-oesophageal reflux (10%) due to delayed gastric emptying, which requires fundoplication.
Gastritis and bleeding peptic ulcer.
Blind-loop syndrome when a primary duodenojejunostomy was performed.
Survival after surgery in cases with isolated duodenal atresia is > 95%. Early operative mortality after correction of DA has been reported to be as low as 4–5%.49 Neonates with Down syndrome or complex cardiac defects have a higher long-term mortality rate. Owing to the above-mentioned late complications patients with DA or stenosis need follow-up into their adult years.
Jejunoileal atresia (JIA) or stenosis is a common cause of intestinal obstruction with an incidence of 1 in 1500–5000 live births.50 Males and females are equally affected. The incidence of obstruction in the jejunum or the ileum is nearly equal. Differences are obvious in the proximal and distal segments (proximal jejunum 31%, distal jejunum 20%, proximal ileum 13% and distal ileum 36%). Single atresia occurs in > 90% of all patients; multiple atresias are reported in 6–20% of cases. These newborns are very often premature. JIA or stenosis can be found at any portion of the gastrointestinal tract.51
In contrast to the recanalization failure seen in DA, the theory of JIA origin is a late mesenteric intrauterine vascular accident (IVA) with ischaemic necrosis of a bowel segment in gestational weeks 11–12. Subsequently, this segment will be reabsorbed.52 The IVAs may be caused by intrauterine malrotation, volvulus, intussusception53 or perforation, gastroschisis and omphalocele.54 IAVs occur after intestinal development because of the presence of bile droplets, meconium or lanugo distal to the atresia.
Multiple atresias have been observed in newborns of mothers who ingested ergotamine and caffeine, or pseudoephedrine alone or in combination with acetaminophen during pregnancy. Cocaine abuse and smoking during pregnancy have also been associated with a higher risk of development of intestinal atresia.55,56
Grosfeld et al.57 have modified Louw's original classification into the following most commonly used description of JIA. In all types the proximal pouch appears extremely dilated and the distal post-atretic part is unused and narrow (Table 4).
Bowel, pink; mesenterium, yellow; intraluminal web, blue; artery, red.
Type I (16%)58 is represented by an intraluminal mucosal web. Similar to DA, it may be elongated forming a ‘windsock’. The bowel wall and the mesentery appear intact. Bowel length is normal.
Type II (21%) shows a fibrous cord separating the proximal and distal segments. Mesentery is intact and bowel length is normal. The proximal pouch is grossly dilated and does not show peristalsis. Bowel perforation may occur. The distal pouch can be slightly distended in the beginning due to retained cellular debris.
Type IIIa (24%) shows two completely separated blind pouches with a V-shaped mesenteric gap. Intestinal length is shortened.
Type IIIb (10%) (‘apple-peel deformity’ or ‘Christmas-tree deformity’) is presented proximal by a blind-ending distended-upper jejunum, where the dorsal mesentery is missing. The distal bowel appears unused, small and helically encircles an artery that arises from the ileocolic or right colic arcades. The superior mesenteric artery is very short and ends at the level of the middle colic branch. This type is very often associated with prematurity and low birthweight.59
Type IV (22%) is a series of multiple atresias of all types (I–III). The result of operative reconstruction of this type is usually a short-bowel syndrome.
Prenatal diagnosis is very important for the planning of the delivery. It allows the intrauterine transfer to a neonatal centre, where delivery and post-natal intensive care including surgical correction can take place. As most children with JIA are premature and have a low birthweight this procedure has a positive effect on survival.
An intestinal obstruction can be suspected via ultrasonography in 18–28% of cases.38 Prenatal ultrasonography reveals a polyhydramnios (28%).51 Persistently dilated bowel loops eventually enlarging in diameter show a correlation with a post-partum JIA in 66%.60
In 35% of cases, neonates with a JIA are premature with low birthweight (25–50%).61,62 Within the first hours the child appears stable and without any clinical symptoms. Within 24 to 48 hours the classical symptoms such as bilious vomiting and extreme abdominal distension without producing any meconium are seen. In case of bowel perforation, the distended abdomen may show redness due to peritonitis (Figure 5a). Sometimes only a very small portion of meconium passes, as the obstruction develops later in gestation than the meconium that is formed out of cellular debris, swallowed amniotic fluid and lanugo hair.
If the obstruction is localized in the proximal jejunum, the upper abdomen is distended whereas the caudal part is flat. In cases of ileal obstruction a diffuse distension of the abdomen is evident and the bowel loops filled with meconium are visible and palpable through the abdominal wall.
High fluid loss into the bowel and additional vomiting leads to dehydration with the typical hypovolamic signs of tachycardia, decreased pulse pressure, less urine and sunken fontanelle. Laboratory tests reveal a metabolic acidosis (serum bicarbonate low, serum chloride high) and an elevation of haematocrit and indirect bilirubin.
Plain abdominal radiographs show dilated intestinal loops with air-fluid levels (Figure 5b). In cases of high obstruction only a few loops with air-fluid levels are seen. The more distal the atresia, the more distended loops fill the abdominal cavity. Distal to the obstruction the abdomen is gasless. Calcifications provide an indication of intrauterine perforation. Contrast enema can be administered and radiographs show a thin unused microcolon. With this method the location of the caecum, proving the evidence of malrotation, can be demonstrated. Free air seen in the radiograph is a sign of perforation (Figure 6). In this case the newborn quickly develops a meconium peritonitis showing life-threatening signs of sepsis.
Differential diagnoses such as adynamic ileus due to sepsis, malrotation, volvulus, meconium ileus or aganglionosis should come into consideration.
The incidence of associated anomalies in patients with JIA is 50–60%. In the literature the following are mentioned: cardiac malformations, TOF, genitourinary tract malformations, gastroschisis (10–20%),63 malrotation, neurological anomalies and cystic fibrosis (10%).
The aim is to reconstruct bowel continuity and to preserve normal length of bowel.
Placing an orogastric tube should achieve gastric decompression. Patients are restricted to NPO. Metabolic and haemodynamic stabilization must be performed before surgical therapy and preoperative intubation might be necessary.
Under general anaesthesia, laparotomy via median incision is performed and the location of the atresia or obstruction is assessed. Further intra-abdominal anomalies should be excluded. Transmural instillation of saline solution into the distal pouch and milking it caudally may reveal distal obstruction.
In type I (Figure 7a), the web can be resected in cases of short bowel length, otherwise a resection of the obstructed part and end-to-end anastomosis is advisable.
In patients with type II or IIIa and normal length of remaining bowel, part of the proximal dilated pouch is resected to avoid post-operative physiological obstruction due to lack of peristalsis.
In patients with type IV, it is the goal to perform an end-to-end anastomosis of the short segments to preserve as much bowel length as possible. If the atretic segments are too short and too small for the anastomosis, or a segmental ischaemia is obvious, resection of this part of the bowel (‘string of sausages’) has to be performed (Figure 7b).
Usually the proximal pouch is extremely dilated, whereas the distal pouch is narrow. To create a similar diameter for the end-to-oblique anastomosis, the dilated part is resected economically. The distal pouch is transected obliquely and the incision is continued along the antimesenteric border64 (Figure 8). Finally, the mesenteric gap has to be approximated and an abdominal drain placed close to the anastomosis.
If there is a difference in diameter bigger than 4 : 1 between the proximal and distal end, a Bishop-Koop enterostomy65 (Figure 9a) (end-to-side Roux-en-Y anastomosis between the end of dilated proximal segment and the side of the unused distal intestine which is then directed out as an enterostomy) or Santulli-Blanc66 (Figure 9b) enterostomy should be performed. These enterostomies have the advantage that they allow deflation of the dilated proximal bowel and at the same time they allow the intestinal contents to pass gradually through the distal unused bowel (low-pressure anastomosis). Thus, the distal bowel gradually dilates and functions.
In case of reduced bowel length (for type III or IV atresias) a proximal antimesenteric tapering enteroplasty may be performed over a 26F tube by diminishing the diameter of the proximal bowel followed by an end-to-oblique anastomosis.67
To preserve maximal bowel length and reduce the risk of short bowel syndrome in type IV atresia, a one-stage repair performing multiple primary anastomoses should be performed.68,69 If there is a perforation with significant contamination or meconium peritonitis, temporary enterostomies at the corresponding level are advisable.
The longitudinal lengthening procedure of Bianchi is a possibility to improve the short gut situation. The dilated proximal bowel is divided longitudinally and hemiloops are created which are anastomosed isoperistaltically.70
Before closure of the laparotomy at least one abdominal drain should be placed close to the anastomoses.
As most patients with JIA need long-term TPN, a central venous catheter (e.g. Broviac®) should be placed during the same anaesthetic procedure, after the laparotomy.
Post-operative monitoring is performed on a NICU where haemodynamic, respiratory and metabolic adjustments are made accordingly. Antibiotic coverage that was started intraoperatively has to be continued for at least 5–10 days and adjusted if necessary. A nasogastric tube provides drainage of the reflux while the bowel shows no peristaltic movements. TPN is administered until signs of propulsive peristalsis (flatus, stool) are obvious. Enteral feeding has to be started carefully.
Early surgical complications (15%) are anastomotic leaks or functional obstructions at the level of the anastomosis.71
The short-bowel syndrome induces a wide spectrum of malnutrition due to malabsorption. At least 10–20 cm of proximal jejunum plus the ileocaecal valve should be preserved in newborns to avoid short-bowel syndrome. Absorption of the bile acid and vitamin B12 takes place in the ileum. If the ileum was resected patients need nutritional supplementation.
Cholestasis and steatorrhoea can occur as a result of long-term TPN.72
Sepsis can occur through lack of glutamine supplementation, which reduces levels of immunoglobulin A and increases bacterial translocation.
The long-term survival rate for children with JIA is > 90%. Surgical mortality rate for neonates is < 1%.49 Mortality is related to sepsis, associated anomalies, prematurity, malrotation, meconium peritonitis, and long-term TPN complications. Ultra-short-bowel syndrome (< 40 cm), requiring long-term TPN, can be complicated by liver disease. Use of growth factors to maximize intestinal adaptation, administration of growth hormone to grow the bowel, nutritional modifications and advances in small bowel transplantation may improve long-term outcomes.73
The incidence of anorectal malformations (ARMs) is 1 in 4000–5000 live births and they affect males more often than females. ARMs may be very complex and include defects not only of the lowest part of the intestinal tract but also of the urogenital tract. Minor defects are easy to treat and show good functional prognosis, whereas complex types with associated malformations are challenging to handle and have a poorer functional outcome that requires long-term follow-up.
The embryogenesis of these malformations remains unclear. Defects in the formation or shape of the posterior urorectal septum at 7–8 weeks' gestation seem to be responsible for many of the described abnormalities of imperforate anus. Interference with anorectal structure development at varying stages leads to various anomalies. A few studies have found that the mutation of a variety of different genes might cause ARMs, or that the aetiology of ARMs is multigenetic.74
The type of ARM is classified according to the classification proposed by MA Levitt and A Pena.75 It describes the anatomical relation of the rectum to the urogenital tract (Table 5). Neonatal recognition of the type of the malformation is essential for the planning of the surgical management76 (Figure 10).
Rectoperineal fistula can occur in males and females. It shows as a cutaneous anal dimple in the centre of a well-developed sphincter. The small and often stenotic fistula opens anterior of it, in the perineal region. Males often have an additional midline skin fold at the anal opening, the so-called ‘bucket-handle’. In males it may occur that a small dark cord containing meconium is running up into the scrotal median raphe. Rectoperineal fistula can be corrected by minimal posterior sagittal anoplasty, which has a very good prognosis in terms of continence.
Rectovestibular fistula shows a small opening at the posterior part of the vestibulum external to the hymen. The operative correction can be performed with or without a colostomy and has good prognosis.
Rectovaginal fistula is very rare and in retrospect it seems that they were misdiagnosed cloacas.75
Cloaca is defined as a common channel (1–10 cm) including urethra, vagina and rectum. Physical examination reveals a single orifice behind the small labia. Colostomy should be performed after birth. The prognosis depends on the length of the common channel and the associated malformations: the longer the channel, the poorer the prognosis. Fifty per cent of patients have two hemivaginas and associated hydrocolpos.
Rectourethral-bulbar fistula is very common. The perineal region of these male patients shows no fistula. Meconium can be detected in urine. Colostomy is performed to prevent recurrent severe urinary tract infections and bowel obstruction. Performing distal colostography via the colostomy will give detailed information about the anatomical situation.
Rectourethral-prostatic fistula is rare. Colostomy is performed. Diagnosis is obtained in a similar way to bulbar urethral fistula.
Rectobladder-neck fistula is diagnosed in 10% of anorectal malformations in males. Colostomy and the combination of abdominoperineal surgical procedures are obligatory. The prognosis for continence is very poor.
Imperforate anus without fistula is a rare type of ARM (5%), mostly associated with trisomy 21. No external fistula is visible, and even after 24 hours meconium has neither passed nor can be detected in urine. If the blind pouch is very close to the anal dimple a dark dot behind a thin membrane is visible (Figure 11a) and a primary minimal posterior sagittal anoplasty, with very good prognosis, can be performed. Higher levels of the pouch, demonstrated in a lateral pelvic radiograph (see Post-natal diagnosis), require colostomy.
Rectal atresia is very rare (1%). The external aspect of the anus appears normal, but on insertion of a tube in the anal canal a stop is felt at 1–2 cm from anal skin.
Antenatal diagnosis is rare. First physical examination of the newborn can reveal an imperforate anus. More complex types need thorough further radiodiagnostic examination.
Sonography shows unspecific signs, such as polyhydramnios, dilated or echogenic bowel, hydrometrocolpos or hydronephrosis. Associated cardiac, vertebral or renal malformations may be detected.
During initial routine newborn physical examination, the perineal region, especially the location of the bowel outlet, has to be inspected. In mild low forms of ARMs this fistula opens at the perineal region, which is located ventral to the well-developed voluntary sphincter complex. Sometimes an anal membrane is visible through which black meconium can be seen.
In females, the fistula can be more ventrally located in the vestibule (Figure 11b).
If no fistula can be detected in the perineal and vestibular region of females, it is vital to look for a vestibular fistula beneath the small labia. If there is only one opening, a cloaca can be diagnosed.
If no external fistula is evident and urinanalysis does not show meconium, it is advocated that physical and urinary examination be repeated after 24 hours because it is possible that the presentation of a tiny perineal fistula is delayed. Shortly after birth the intra-abdominal pressure is not high enough to overcome the tone of the muscles that surround the rectum. This might take up to 24 hours; the decision of performing a colostomy should not be made until then.
In more severe or high anomalies the muscles are poorly developed. Physical examination reveals that the midline gluteal fold and the anal dimple are missing: a so-called ‘flat bottom’. No outer fistula is evident and the bowel opens ectopically in the male urogenital tract or female genital tract. Most of these malformations require a colostomy.
Rare types of anal atresia are often detected when a tube is placed to facilitate meconium passage.
In order to estimate the distance between the air-distended rectal pouch and a radio-opaque marker on the anal dimple, a cross-table lateral pelvic radiography at 24 hours post partum is performed. A distance of more than 1 cm requires a colostomy. Less than 1 cm can be treated as a perineal type of ARM.
In children with a colostomy, augmented-pressure distal colostography can be performed to give detailed information about the height of the rectum and the type of rectourinary communication. Water-soluble contrast medium is injected via a blocking balloon catheter into the distal stoma. In the case of fistula, contrast medium passes into the male bladder or urethra or into the vagina. Otherwise, the pouch shows a blind round ending.
Ultrasonography has to be performed to look for associated abdominal and urogenital anomalies. Hydrocolpos very often appears as cystic mass in the pelvic region in females born with cloaca. Secondary hydronephrosis due to obstruction of the ureters can be diagnosed.
Plain radiography of the sacrum (anteroposterior and lateral) and lumbal vertebrae may detect defects in that region (e.g. hemivertebrae, hemisacrum). In this case, abdominal ultrasonography should be performed to exclude the presence of a presacral mass, (dermoid, teratoma, anterior meningocele) which might affect operative management and prognosis.
With spinal sonography a tethered cord can be detected within the first 3 months. Thereafter, MRI provides evidence of the lower ending cord and shows suspected additional meningomyelocele and syringomyelia.
Echocardiography has to be carried out to exclude additional cardiovascular malformations.
Urinanalysis can give valuable information in the case of doubtful rectourinary fistula.
Associated malformation include:
Cardiovascular malformations (12–22%). The most common lesions are tetralogy of Fallot and ventricular septal defects. Transposition of the great arteries and hypoplastic left heart syndrome have been reported but are rare.
Gastrointestinal malformations such as OA with TOF (10%), DA or duodenal obstruction due to annular pancreas may be present.
Vertebral anomalies predominantly in the lumbosacral region increase the risk of incontinence.
The sacrum often shows deficiency that can be measured by calculating the sacral ratio in a lateral-plane radiograph. Hemisacrum is often associated with a presacral mass (dermoid, teratoma, anterior meningocele).
Spinal malformations such as a tethered spinal cord occur in 25–35%.77 The higher the complexity of the ARM, the more often tethered cord is evident. The low-ending spinal cord has a negative impact on the functional prognosis of urinary and faecal continence. In addition, patients have a less developed perineal musculature.
Other spinal malformations such as syringohydromyelia or myelomeningocele can occur.
Urological abnormities include hydronephrosis and vesicoureteric reflux, which are frequent findings, followed by renal agenesis and dysplasia. Cryptorchidism occurs in 3–19% of males.
Vaginal abnormities include large hydrocolpos which may cause hydronephrosis obstructing the ureters, vaginal septum (50%), vaginal duplication and agenesis.
Uterine abnormities include bicornate uterus and uterus didelphys (35%).
Depending on the type of ARM, a primary repair in the neonatal period or colostomy and staged repair is performed. Associated life-threatening malformations have to be treated first.
Newborns with the diagnosis of imperforated anus with or without fistula, should be put on intravenous hydration and nutrition. A nasogastric tube is placed to decompress the stomach. Surgical procedure based on the examination findings has to be planned and performed within the first 24–48 hours to avoid perforation of the blind colon pouch. Especially in cases of suspected urogenital fistula broad-spectrum antibiotics should be administered. If in the case of cloaca a hydrocolpos is diagnosed, a decision regarding drainage is required to avoid sepsis or metabolic acidosis.78 Diagnosis of associated malformations is necessary and life-threatening diseases must to be treated immediately.
In 1982 Pena and de Vries introduced the posterior sagittal anorectoplasty (PSARP) for the surgical correction of anorectal malformations.80 This allows surgeons to view the anatomy of these defects clearly, to repair them under direct vision, and to learn about the complex anatomical arrangement of the junction of rectum and genitourinary tract.75,79,80
Minimal posterior sagittal anoplasty without colostomy is performed in patients with perineal fistula. With the patient positioned in suppine position with elevated pelvis, the fistula and a short part of the rectum are carefully dissected. A small midline incision dorsal to the fistula allows division of the external sphincter complex whereto the rectum is then placed and anoplasty is performed. Finally, the perineal region is reconstructed.
To perform repair of rectovestibular fistulas without colostomy requires an experienced surgeon to avoid post-operative complications such as dehiscence or infection that may result in functional problems.
In higher, more complex anomalies initially descending colostoma should be performed followed by PSARP after 1 to 2 months. Ten per cent of male patients need additional laparotomy to mobilize the rectum, and in 30% of cloacas laparotomy81,82 or assisted-laparoscopic techniques are used to mobilize the high rectum or vagina.83–85
Cloacal repair should be performed in specialized centres with experienced surgeons.86 The challenge is to separate the common wall between rectum and vagina and between vagina and urinary tract and following repair or reconstruction of the vagina and/or urethra. For patients with a common channel longer than 3 cm, primary colostomy and delayed PSARP with additional laparotomy is required. The same procedure is used in male rectobladder neck fistula.
Newborns with rectal atresia require primary colostomy and delayed repair by the posterior sagittal approach and end-to-end anastomosis between the upper blind rectal pouch and the anal canal.
For performing PSARP the patient is placed in a prone position with elevated pelvis. A midline sagittal incision between the buttocks is performed. Precise midline dissection is achieved using an electric stimulator to determine the magnitude of the sphincter muscle contraction, which has to be equal on both sides. Midline preparation also guarantees that nerves will not be injured. When the rectum is identified and exposed first the fistula has to be dissected and closed. Then the rectum is carefully separated from the thin common wall to the male urethra or female dorsal vagina. The rectum has to be mobilized circumferentially to gain length to reach the perineum. It is then placed in front of the levator muscle and within the limits of the muscle complex and the external sphincter (Figure 12). Finally, an anoplasty for the creation of a neoanus is performed.87,88
In high anorectal malformations an additional abdominal approach is required.
In all correction procedures a Foley catheter should be placed into the bladder and it should stay for a period of at least 5–7 days.
The ideal colostomy is made out of the descending part of the colon in the left lower quadrant of the abdomen. The stomas have to be separated.89 This has the advantage of preventing spillage of stool from proximal to distal bowel, which avoids impacted distal stool and urinary tract infection in the case of rectourinary fistula. Furthermore, it is easy to keep the distal short bowel part clean by performing regular irrigations. When a colostoma is first created, immediate irrigation is necessary to remove meconium and prevent the development of a megasigmoid. In cases of large rectourinary fistulae in which the patient passes urine into the bowel, the urine comes out easily through the mucous fistula, avoiding problems of hyperchloraemic acidosis due to urine absorption. Keeping the sigmoid loop distal to the colostomy has the advantage of leaving enough bowel length to reach the perineum during PSARP.76 The colostomy can be closed 3 months after successful repair of the perineal malformation.
Three to four weeks after surgical repair, a regular dilation schedule of the neoanus should be instituted to prevent post-operative stenosis. Parents are taught how to pass the dilator and they are expected to continue the programme of slow progressive dilation twice a week until the dilator size appropriate to the child's age is reached. However, it has to be continued by tapering the frequency of dilatations88 (Table 6).
|Patient's age||Dilator Hegar number|
|> 12 years||17|
If the dilations are spaced too far apart, the anus can narrow between dilations and the risk of stenosis is increased. On the other hand, large dilations provoke tears. Tears heal with scar tissue, which also causes stenosis.
Intestinal perforation of the blind rectal pouch during the period of 24 hours after birth, when diagnostic analysis is performed and meconium has not passed to localize a tiny fistula.
Intraoperative injury of the posterior urethra, seminal vesicles, vas deferens or ectopic ureters.
Post-operative dehiscence or local infection when no colostomy was performed.
Neoanal stenosis due to scar tissue resulting from wrongly-performed post-operative dilation, which was either not done regularly or with too large dilations.
Perforation during anal dilations performed by the parents.
If mild types of ARMs or urogenital sinus are not discovered in the newborn period, the children may present later with urinary tract infections and/or constipation.
Constipation is the most common post-operative morbidity in patients with mild types of ARMs. It is defined as the patient's inability to have bowel movement and empty the rectum without the aid of laxatives, enemas or diet. Untreated, it leads to faecal impaction and overflow pseudoincontinence with constant soiling, also known as encopresis. Parents must be educated to force daily stool passage using laxatives and diet to prevent constipation. Patients become continent again after managing the constipation.
Faecal and urinary incontinence is mostly associated with higher types of ARMs (e.g. cloacae with long-common channel, rectoprostatic or rectobladder neck fistula) related to the associated poor development of sphincter muscles, sacrum and nerves in that region. Voluntary bowel movement, defined as the act of feeling the urge to go to the toilet and the ability to verbalize it and hold back defecation if necessary, is not possible.90 Parents have to be made aware of regular bowel management, which involves cleaning the child's colon once a day by the use of a suppository, an enema or colonic irrigation91 and intermittent catheterization. Patients who undergo rectal resection during abdominoperineal correction very often suffer from recurrent diarrhoea because the rectal reservoir is missing.76
The artificial bowel sphincter and electrically stimulated gracilis neosphincter are two techniques that have been used for the treatment of patients with severe refractory faecal incontinence.76
The functional results of the repair of anorectal anomalies seem to have significantly improved since the advent of the posterior sagittal approach. Most children with perineal fistula (99%), females with a vestibular fistula (90%) and males with a bulbourethral fistula (80%) should be continent. For higher types of ARMs showing poorly developed muscles or nerves, no adequate repair has been developed to guarantee continence. In patients with cloacal malformations it is important to aim for bowel and urinary control as well as normal sexual function. Rarely, all three can be achieved.92
Adult patients still have to cope with substantial functional problems ranging from mild constipation to severe faecal and/or urinary incontinence.85 In long-term functional outcome studies we reported a significantly lower score compared with healthy controls.93 However, regular controls, continuous education about bowel management regimens, intermittent catheterization or the option of continent diversion may provide a better quality of life with social acceptance.