Jejunoileal Atresia and Stenosis
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Jejunoileal atresia, defined as a congenital defect in continuity of the bowel, is a common cause of intestinal obstruction in the newborn. The incidence of jejunoileal atresia varies from 1 in 330 and 1 in 400 live births to between 1 in 1500 and 1 in 3000 live births. Jejunoileal occlusions occur more frequently than duodenal or colonic. The management of jejunoileal atresia has been one of the great success stories of pediatric surgery of the twentieth century. An initial more than 90% mortality up to 1950 was turned to a >80% survival with a simple change in surgical technique prompted by innovative surgical experiments on fetal puppies performed by Barnard and Louw – the first steps in fetal surgery. With improved neonatal and perioperative care, safe anesthesia, refined surgical techniques, and better management of short bowel syndrome, a survival rate of greater than 95% can be expected in well-resourced centers. This chapter describes the current approach to the diagnosis and management of jejunoileal atresia of the newborn.
KeywordsCongenital Intestinal Atresia
Atresias and stenoses of the jejunum and ileum are common causes of bowel obstruction in the neonate and account for about one third of all cases of neonatal intestinal obstruction with necrotizing enterocolitis, midgut volvulus, anorectal malformations, cystic fibrosis, congenital segmental dilatation of the intestine, and Hirschsprung’s disease as differential diagnoses. A third of infants with these conditions are born prematurely or small for their gestational age (Stollman et al. 2009). Stenoses are less frequently seen, occurring in about 5% of cases, and seldom present in the newborn period due to delay in diagnosis (DeLorimier et al. 1969).
In the early days of pediatric surgery, outcomes after surgery, whether end-to-end anastomosis or stoma formation, were associated with a generally poor prognosis. Factors contributing to this historic poor prognosis included delayed presentation, frequent ischemia, and necrosis of the proximal bowel due to pressure-induced distension and/or volvulus of the proximal bulbous dilated segment and dysmotility of the dilated segment of the bowel proximal to the obstruction if not resected or tapered at the time of surgery following end-to-end anastomosis with the absence of parenteral nutritional support. An understanding of the etiology and the realization that the proximal blind-ending dilated bulbous atretic bowel was the cause of poor prograde peristalsis and that resection of this segment with primary anastomosis of proximal to distal bowel solved this problem led to a dramatic improvement in outcomes from a mortality of 90–100% to a survival of over 80% in the 1950s’ even without parenteral nutritional support (Haller et al. 1983; Louw 1967; Nixon 1955).
The incidence and type of intestinal atresia vary widely among different countries and geographical areas. In Europe and the USA, this is around1: 3000 to 1:10,000 live births and in Africa nearer to 1:1000 live births where types III and IV are more frequent. There also appears to be an increased incidence in twin pregnancies at 7.3 per 10,000 live births (Adeyemi 1989). The male-to-female ratio is equal in most reports. There have been other familial associations reported, but to date, a specific gene mutation has not been discovered.
Our present understanding of the etiology of intestinal atresias is based upon the classic experimental work of Louw and Barnard reported in1955 (Louw and Barnard 1955). These investigators observed that ligating mesenteric vessels and causing strangulated bowel obstruction in fetal dogs resulted in atretic lesions of the small intestine that were similar to those observed clinically in human neonates. Thus, atresias and stenoses of the small intestine are believed to be due to an ischemic insult. The ischemic bowel is resorbed and both ends heal resulting in two blind ends. The proximal end becomes distended in time with pressure from prograde peristalsis of swallowed liquor and intestinal secretions. This etiologic mechanism explains the frequent association of atresias with mesenteric defects and with other conditions that may cause strangulated obstruction of the intestinal tract (e.g., volvulus, intussusception, internal hernias, and gastroschisis). An ischemic etiology may also explain why intestinal atresias are often associated with maternal smoking and vasoconstrictor drug exposure during pregnancy. Caffeine and ergotamine tartrate use for migraines in late pregnancy, as well as the used of pseudoephedrine and acetaminophen, has been associated with an increased incidence (Graham et al. 1983). Other suggested causes have been placental insufficiency or intermittent midgut volvulus. There is a greater incidence of cystic fibrosis and malrotation in association with jejunal atresia compared with ileal atresia (Sweeney et al. 2001).
There have also been several case series reports of familial small bowel atresia, most frequently type IV lesions (Mishalany and Najjar 1968). The apple-peel variety may also be associated with a familial pattern, and in this situation patients typically present as premature, low birth weight babies and have associated malrotation and other congenital abnormalities (Blyth and Dickson 1969). More recently some of the established concepts of bowel development and rotation have been questioned (Nichol et al. 2011; Shorter et al. 2006).
Clearly the usual type of jejunoileal atresia described is quite different from the familial multiple atresias of the whole gastrointestinal tract seen in severe immune deficiency syndrome, which is an autosomal recessive condition (Cole et al. 2010).
However the localized nature of the vascular accident occurring late in fetal life would explain the low incidence (less than 10%) of congenital coexisting malformations other than the intestine, as well as the observation that bile pigments, lanugo hair, and squamous cells may be found in the lumen distal to the atretic segment. There is a low incidence of less than 1% of an association of proximal jejunal atresia and duodenal atresia, and there have been isolated reports of biliary atresia and jejunal atresia.
Atresias occur equally in the jejunum and ileum, with the distal ileum and proximal jejunum being the most frequent sites. While most atresias are single, around 10% can be multiple and these usually involve the proximal jejunum.
Stenoses occur in 5–10%. In this situation the proximal and distal bowel are in continuity with an intact mesentery. At the point of stenosis, there is a short rigid segment with a narrow but patent lumen. There is a normal length of the intestine.
Type I atresia (~23%) is a transluminal septum (membrane or web) with dilated proximal bowel in continuity with collapsed distal bowel. The bowel is usually of normal length.
Type II atresia (~10%) involves two blind-ending atretic ends separated by a fibrous cord along the edge of the mesentery with mesentery intact. The total bowel lost approximates the length of the atretic cord, and thus prognosis is generally good.
Type IIIa atresia (~15%) is similar to type II, but there is a V-shaped mesenteric defect. The total bowel length is always foreshortened.
Type IIIb atresia (19%) (“apple-peel” or “Christmas tree” deformity) consists of a proximal jejunal atresia near the ligament of Treitz, usually with malrotation and the absence of most of the mesentery. Prematurity and low birth weight are common. This type is the result of an extensive infarction of the proximal midgut secondary to an occlusion of the superior mesenteric artery just distal to the middle colic origin. A varying length of ileum survives coiled around a single artery with perfusion from retrograde flow via an arcade of the right colic or middle colic artery. Occasionally there may be further type I and II atresias along the length of the coiled bowel. There is always significant reduction in intestinal length; thus, these babies may develop short bowel syndrome and have an increased morbidity and mortality. Familial incidence of this type has been reported (Seashore et al. 1987).
Type IV atresia is a multiple atresia of types I, II, and III and appears clinically to look like a string of sausages. The viable bowel length is always reduced. The site of the initial atresia determines if it is a jejunal or ileal atresia. The terminal ileum, as in type III, is usually spared.
The intestine proximal to the atresia is subject to increased pressure due to ongoing fetal ingestion of amniotic fluid. This may lead to a cyanotic appearance of the dilated segment as well as some areas of necrosis. Pre- or postnatal perforation may develop. Histological and histochemical abnormalities have been observed up to 20 cm proximal to the obstruction, clinically presenting as reduced or ineffective peristalsis. Distally the bowel is disused and narrow, but essentially should have normal peristaltic function.
Atresias of the jejunum are frequently associated with polyhydramnios. The more proximal the atresia, the higher the incidence with up to 38% of cases of proximal jejunal atresia displaying polyhydramnios. Fetal diagnosis with ultrasound scanning may be made where, in addition to polyhydramnios, dilated echogenic and thickened bowel with increased peristalsis and distal decompressed bowel can be identified (Wax et al. 2006). Prenatal ultrasound, however, has a relatively poor predictive value and is unreliable in detecting atresias with less than a third of cases being detected (Wax et al. 2006). As suggested by the etiology, the later the ultrasound in gestation, the more likely it will be to define the atresia. The use of fetal MRI scanning is increasing and may be more valuable in the prenatal diagnosis of bowel atresia (Veyrac et al. 2004).
Many of these patients are born prematurely and often are small for their gestational age due to inability to absorb nutrients from the amniotic fluid in patients with proximal intestinal obstructions (Surana and Puri 1994). The more proximal the atresia, the higher the incidence of low birth weight infants. Nearly all infants with intestinal atresias develop symptoms within hours after birth; however, several publications have documented that neonates in developing countries often do not reach definitive medical care for several days. Unlike atresias, most patients with intestinal stenoses are not diagnosed until well beyond the neonatal period.
Intestinal atresia should be suspected in any newborn showing evidence of bowel obstruction (bilious vomiting, abdominal distension, and failure to pass meconium). Aspiration of >25 ml of fluid from the stomach via a nasogastric tube (NGT) is very suggestive of obstruction. Proximal atresias may show little or only upper abdominal distension. The more distal the atresia, the more generalized the abdominal distension. After aspiration of gastric contents, the abdomen will be less distended and visible peristalsis may be observed. There is usually a failure to pass meconium, and typically small-volume gray mucoid stools are passed. The passage of meconium, however, does not exclude an atresia as meconium distal to the atresia may be present in late-onset lesions. Occasionally, if ischemic bowel is present, as in type IIIb atresia, blood may be passed rectally.
Abdominal tenderness, distension, or peritonitis develops only with complications of ischemia or perforation. This commonly occurs with a delay in diagnosis in the more distal atresias and is due to increased intraluminal pressure from swallowed air and/or secondary volvulus of the bulbous blind-ending bowel at the level of the first obstruction.
It may also demonstrate the position of the cecum, thus giving information regarding bowel rotation – which is abnormal in 10–15% of cases. A high jejunal atresia associated with malrotation on contrast enema is very suggestive of type IIIb atresia. Preoperative demonstration of a patent colon is also helpful in that confirming colonic patency by injection of saline at operation, a sometimes tedious procedure, is not required (Fig. 3).
In patients with intestinal stenoses, plain abdominal x-rays may demonstrate proximal bowel dilatation; however, in most patients a gastrointestinal contrast meal or enema is required to confirm and locate the site of partial obstruction.
The differential diagnosis includes other causes of intestinal obstruction in the neonate.
Malrotation with or without volvulus may be suspected when there is minimal abdominal distension accompanied by bilious vomiting. The presence of multiple dilated bowel loops without air-fluid levels suggests the possibility of meconium ileus, particularly if the intestinal content has a “ground-glass” appearance. In patients with multiple dilated bowel loops, suggesting a distal obstruction, the differential diagnosis includes several conditions for which surgical intervention may not be required. Therefore, in these patients a contrast enema may be helpful to look for evidence of a meconium plug or meconium ileus, which may respond to nonoperative management. In addition, a contrast enema may demonstrate findings suggestive of Hirschsprung’s disease, which would direct initial management toward obtaining confirmatory tests for this disease.
Summary of diagnostic workup and management of Jejunoileal atresia and stenosis (Adapted from Haller et al. 1983)
Polyhydramnios, affected family: ultrasonography, MRI
Fluid management: maintenance and replacement
Correction of electrolyte abnormalities
Transfer to a pediatric surgery center
Radiology: abdominal radiograph, contrast enema, contrast meal if stenosis suspected
Assessment for associated malformations
Identify type of atresia
Establish distal patency
Bulbous component: resect, taper, or plicate if short residual length
De-rotate and taper if high jejunal atresia
Preserve maximal distal bowel length – measure residual bowel
End-to-end single-layer interrupted anastomosis
Early graduated enteral feeds: breast, special, or polymeric feeds
Short bowel syndrome
Associated congenital abnormalities
Operative techniques need to be individualized according to the type of atresia, length of residual bowel, presence of complications, and surgeon capabilities. In addition, associated pathologies or defects (meconium peritonitis, gastroschisis) may influence the procedure performed. Exploration is usually via a supra-umbilical transverse incision although minimally invasive periumbilical incisions and laparoscopy are increasingly employed (Banieghbal and Beale 2007; Lima et al. 2009; Li et al. 2015).
The basic concepts of the surgical procedure are to immediately isolate the site of perforation to avoid further contamination of the peritoneal cavity, identify all atresias, resect and/or narrow the proximal dilated segment, preserve sufficient bowel length, and restore continuity of the bowel. In most cases of simple atresia, primary anastomosis is safe and stomas are not required.
The entire bowel is exteriorized. The site of the most proximal atresia is readily identified as the site of marked change in intestinal caliber. The outer wall of the intestine at the site of obstruction may appear intact, or there may be an associated defect in continuity of the intestine and the mesentery. Generally, surgical treatment requires excision of the ends of the intestine involved in the atresia. It is also important to look for distal sites of obstruction, which can occur in up to 20% of patients and may not be immediately obvious due to lack of caliber change beyond the proximal atresia. These distal points of obstruction can be identified by flushing the distal intestinal lumen with saline to confirm intestinal continuity to the level of the rectum. Preoperative placement of a transrectal catheter may aid in this process if a contrast enema has not been performed.
The immediate consequence of an atresia is dilatation of the bowel for a variable distance proximal to the first occlusion encountered. This dilated bowel, even when the obstruction is relieved by resection and anastomosis or stoma formation, remains dilated, having inefficient prograde peristalsis. Surgical strategies to overcome this include back resection of this bowel to a near normal-caliber intestine if sufficient residual length (more than 75 cm plus ileocecal valve) or reduction in diameter by various tapering maneuvers (Grosfeld et al. 1979; Thomas and Carter 1974).
After resection of the atretic segment on both sides of the defect (~10 cm on the proximal and 2 cm on the distal side), the surgeon is faced with the sometimes difficult task of reestablishing continuity between intestinal segments with marked size discrepancies. Another consideration is the potential dysmotility of the proximal markedly dilated segment, which may result in delayed intestinal function and problems with bacterial overgrowth (Doolin et al. 1987). Therefore, in patients with a relatively short segment of severely dilated proximal intestine, resection of the dilated segment with reestablishment of continuity by end-to-end anastomosis is a good option. This is best achieved by end-to-end extra-mucosal single-layer anastomosis using 5–0 or 6–0 polydioxanone sutures with larger gaps between interrupted sutures on the dilated segment. Prior to anastomosis, the distal end of the bowel may need to be gently dilated by applying a non-crushing clamp 6–8 cm beyond the distal blind end and distension with normal saline injection, being careful not to split the serosa. Transection of the distal bowel slightly obliquely and extension of this incision along the anti-mesenteric border may render the opening about equal to that of the proximal bowel. Discrepancies in size of bowel lumen of up to 8:1 have been accommodated using these techniques. However, an end-to-end anastomosis is thought to result in earlier return of normal peristalsis and is preferable where the lumen discrepancy is 4:1 or less.
In patients with long segments of proximal intestine that are significantly dilated, resection of the whole involved segment may result in inadequate remaining intestinal length to allow absorption of enteric nutrients, i.e., short bowel syndrome. Therefore, these patients require either imbrication or tapering enteroplasty of the proximal dilated segment. To date, no randomized studies have compared the outcomes for patients with intestinal atresia with or without the addition of an enteroplasty or inversion plication.
In patients for whom the atresia is just distal to the duodenojejunal flexure, it may be advantageous to resect the dilated bowel up to the third part of duodenum and de-rotate and taper the duodenum with primary anastomosis (Kling et al. 2000). It is important to be careful to avoid cutting back too far such that the pancreas and ampulla of Vater are protected. Passage of a trans-anastomotic feeding tube for early commencement of enteral feeding is a useful adjunct to postoperative nutrient support particularly if delay in restoration of foregut function is expected due to gross dilatation of the proximal bowel and if parenteral nutrition is not available, a situation still common in many parts of the world. A trans-anastomotic tube can either be passed via the nasogastric route or via a Stamm gastrostomy performed on the anterior aspect of the stomach.
The bowel should be displayed in a position of non-rotation keeping the free mesenteric border in sight, and restrictive fibrotic bands along this free edge should be divided prior to primary anastomosis to enhance blood supply and venous drainage. The mesentery from any resected bowel is retained and may assist in closure of mesenteric defect (Millar et al. 2000). This technique is very helpful and prevents kinking or distortion of the anastomosis. Furthermore, the potential for kinking the single marginal artery and vein requires careful placement of the bowel into the peritoneal cavity at the completion of the anastomosis.
In infants with congenital short bowel, autologous intestinal reconstructive surgery (AIRS) such as the serial transverse enteroplasty procedure (STEP) and lengthening and tailoring procedures (LILT, Bianchi) have no defined place at the initial operation although sporadic reports have appeared in the literature (Bianchi 1980; Wales and Dutta 2005). It would seem wiser to perform a primary end-to-end anastomosis and allow for adaptation to progress before intervening surgically when a plateau of enteral tolerance has been achieved and the infant is well grown and outside the neonatal period. The fashioning of stomas, e.g., Bishop-Koop, Santulli, Rehbein, or double barrel, as practiced by some, is not routinely advocated unless there is gross intraperitoneal contamination, making a primary anastomosis unsafe. The Bishop-Koop stoma seems to be particularly associated with an increased incidence of complications.
Jejunoileal atresia associated with a gastroschisis is treated by resection and primary anastomosis if there is limited edema and matting from amniotic peritonitis. If there is marked edema and matting, initial reduction of the eviscerated bowel with the atresia intact and primary closure of the abdominal wall defect, if possible, is preferred (van Hoorn et al. 1985). After allowing for disappearance of the edema (10–14 days), a second laparotomy is performed with resection of the atretic segment and primary anastomosis. In the long term, there is up to 20% incidence of prolonged dysmotility, which may benefit from surgical interventions of tapering or imbrication. The so-called closed gastroschisis may be associated with the both exit and entry level atresias with loss of intestinal length. Serial antenatal ultrasound scanning may show increasing bowel dilatation which should prompt earlier preterm delivery (Houben et al. 2009).
It is important to note that enteroplasties, excision of membranes, and bypass techniques are not recommended in patients presenting with jejunoileal stenosis as these procedures fail to remove the dysfunctional segments.
Postoperative care requires nasogastric decompression for several days after the operation (longer for high jejunal atresias). Therapeutic antibiotics are usually continued for 5–7 days or longer directed by culture of gastric aspirate and enteric content, and an oral antifungal agent is given prophylactically. Parenteral nutrition is given initially and weaned slowly as enteral feeding is increased as per protocols. There is increasing evidence that keeping the daily fat load to 1 gm/kg body weight and the use of fish oil-containing lipid will reduce the incidence and severity of parenteral nutrition-associated liver disease (Hess et al. 2011).
Gavage feeding can begin as soon as there is evidence of bowel peristalsis. If a trans-anastomotic tube has been placed, hourly feedings can commence in small volumes from the day following surgery. Oral intake is commenced when the neonate is alert and sucks well, and there is evidence of prograde gastrointestinal function, i.e., clear gastric effluent of low volume, a soft abdomen, and stools have been passed.
Surveillance should continue until the infant has established normal gastrointestinal function. If at any time there is suspicion of a leak at the anastomosis (suggested by ileus, abdominal distension, vomiting, and peritonitis), a plain radiograph of the abdomen should be taken. If this reveals free air in the abdomen more than 24 h after operation, which is indicative of bowel perforation, laparotomy should be performed immediately and the leaking site sutured or the anastomosis redone.
The most common postoperative complication is a functional obstruction at the site of anastomosis. Unfortunately, this complication may be due to the underlying intestinal dysmotility associated with this anomaly and may not be preventable by changes in surgical technique. Other less commonly observed complications include anastomotic leak and adhesive obstructions. HIV infection or exposure is associated with a higher incidence of anastomotic breakdown and wound sepsis with dehiscence. Obstructions due to missed distal unrecognized atresias should not occur and can be prevented by proper evaluation at the time of the initial operation. Persistent bowel dysfunction or obstruction requires a full evaluation with radiography and may necessitate a revision of anastomoses or unkinking of bowel or division of adhesions. These complications are more commonly seen in types 111b and IV atresias.
Prognosis and Outcomes
Before 1952 the mortality rate for congenital atresias of the small intestine even in the best centers was around 90% (Louw 1952). Between 1952 and 1955, there was moderate improvement in outcome due to improved neonatal care (Benson 1955). At that stage most were treated by primary anastomosis either end to end or end to side without resection. With liberal resection of the blind ends and end-to-end anastomosis, the survival rate increased to 78% during 1955–1958 in one center (Louw 1967). Further improvements in neonatal care and management of short bowel syndrome have achieved survivals of near to 100% in some series (Baglaj et al. 2008). However, although mortality rates have improved, greatly about a quarter of the patients may require further surgery (Yeung et al. 2016) to deal with adhesions, stenosis, and dilated bowel with lysis of adhesions, resection, and end-to-end anastomoses with tapering, serial transverse enteroplasty, or a Bianchi procedure if bowel proximal to an obstruction is very dilated.
Conclusion and Future Directions
The management of intestinal atresia is now well defined with an excellent outcome. Diagnosis should be made earlier during gestation, and judicious antenatal counseling of the parents is required with birth in a specialist center preferred. Dysfunctional and short residual bowel may require prolonged bowel rehabilitation and further autologous intestinal reconstruction surgery. Further study into the etiology of the familial variety is required to understand the mechanisms of causation.
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