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CHAPTER 22

INTRODUCTION

Defects in the continuity of the small bowel can mor-phologically be divided into either stenosis or atresiaand represent one of the most common causes ofneonatal intestinal obstruction. Jejuno-ileal atresiahas a prevalence rate of approximately 1:1000 livebirths, with a third of the infants being either bornprematurely or small-for-date. The anomaly is rarelygenetically determined and <1% of babies will havechromosomal or other associated anomalies.

Most jejuno-ileal atresias or stenoses result from alocalized intra-uterine vascular insult to the develop-ing bowel with ischaemic necrosis and subsequentreabsorption of the affected segment(s). Additionalpathology in the form of intra-uterine fetal intussus-ception, malrotation and midgut volvulus, throm-boembolic occlusions, transmesenteric internal her-nias and incarceration or snaring of fetal bowel in agastroschisis or exomphalos further supports theischaemic hypothesis. The ischaemic insult also ad-versely influences the structure and subsequentfunction of the remaining bowel. Histological andhistochemical abnormalities can be observed up to20 cm cephalad from the end of the atretic proximalsegment. The distal bowel is unused and potentiallynormal in function.

Prompt recognition of intestinal atresia is essen-tial for the early institution of management.A prena-tal history of polyhydramnios and ultrasonographyshowing dilated and obstructed fetal intestine arestrong indicators of congenital intestinal atresia. Apositive family history will help to identify heredi-tary forms. Postnatally, intestinal atresia or stenosismay present initially with large intragastric volumesat birth (>20 ml gastric aspirate) followed by persis-tent bile-stained vomiting. In 20% of children symp-toms may be delayed for more than 24 h. Abdominaldistension is frequently present from birth and the

more distal the obstruction the more generalized theabdominal distension. Proximal jejunal atresia oftenpresents with gastric distension and one or two loopsof visible bowel in the upper abdomen relieved bynasogastric tube aspiration. With delay in presenta-tion increasing intraluminal pressure and/or secon-dary torsion of the proximal atretic distended bowelmay lead to ischaemia, perforation and peritonitis.

The differential diagnosis includes midgut volvu-lus, intestinal stenosis, meconium ileus, duplicationcyst, internal hernia, strangulated inguinal hernia,Hirschsprung’s disease and ileus due to sepsis, birthtrauma, maternal medications, prematurity or hypo-thyroidism.

The diagnosis of jejuno-ileal atresia can be estab-lished in most cases by an abdominal roentgenogramwith air as contrast medium. Erect and supine ab-dominal radiographs show distended air and fluidfilled loops of bowel.

The lower the obstruction the greater the numberof distended loops of bowel and fluid levels that willbe observed. Occasionally intraperitoneal calcifica-tion may be seen on the plain radiographs signifyingintrauterine bowel perforation, meconium spill anddystrophic calcification. In the presence of completeobstruction a contrast enema is usually performed toconfirm the level of obstruction and document thecalibre of the colon, exclude colonic atresia, and to lo-cate the position of the caecum as an indication ofmalrotation. With incomplete upper small bowel ob-struction an upper gastrointestinal contrast study isindicated to demonstrate the site and nature of theobstruction and to exclude midgut volvulus.

The clinical and radiological presentation of jeju-no-ileal stenosis will be determined by the level anddegree of stenosis. The diagnosis is often delayed foryears because of subclinical symptoms and findings.

Jejuno-ileal AtresiaHeinz Rode, Alastair J.W. Millar

Heinz Rode, Alastair J.W. Millar214

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The morphological classification of jejuno-ileal atre-sia into types I–IV has significant prognostic andtherapeutic implications. The most proximal atresiadetermines whether it is classified as jejunal or ileal.Although single atresias are most commonly en-countered, 6–12% of infants will have multiple atreticsegments and up to 5% may have a second colonicatresia. The appearance of the atretic segment is de-termined by the type of occlusion, but in all cases themaximum dilatation of the proximal bowel occurs atthe site of the obstruction and is often hypoperistal-tic and of questionable viability when presentation isdelayed.� Stenosis (12%) is characterised by a short local-

ized narrowing of the bowel without discontinuityor a mesenteric defect. The bowel is of normallength.

� Atresia type I (23%) is represented by a translumi-nal membrane or short atretic segment causingcomplete intestinal obstruction. The bowel re-mains in continuity, has no mesenteric defect, andis of normal length.

� Atresia type II (10%) has the blind-ending proxi-mal bowel attached to the collapsed and underde-

veloped distal bowel by a fibrous cord along theedge of the mesentery. The proximal bowel is dis-tended and hypertrophied for several centimetres.There is no mesenteric defect and the bowellength is not foreshortened.

� Atresia type III(a) (16%) is similar to type II ex-cept that the fibrous connecting cord is absent andthere is a V-shaped mesenteric defect. The bowellength may be foreshortened.

� Atresia type III(b) (apple peel) (19%) consists of aproximal jejunal atresia often with associatedmalrotation, absence of most of the superior mes-enteric artery and a large mesenteric defect. Thedistal bowel is coiled in a helical configurationaround a single perfusing artery arising from theright colic arcades. There is always a significantreduction in intestinal length. The infants are usu-ally of low birth weight and may have associatedanomalies.

� Atresia type IV (20%) represents multiple seg-ment atresias like a string of sausages or a combi-nation of types I–III. Bowel length is always re-duced.

Figure 22.1–22.3

Chapter 22 Jejuno-ileal Atresia215

Stenosis Type I

Type II Type III(a)

Type III(b)

Type IV

Figure 22.1

Figure 22.2

Figure 22.3

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Figure 22.4

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The infant is placed supine on a warming blanket andthe exposed abdomen cleaned and sealed with plas-tic adherent drapes.Access to the abdominal cavity isobtained through an adequate transverse supra-um-bilical incision transecting the rectus abdominismuscles. The ligamentum teres is divided betweenligatures.

Exploration and basic surgical considerations: thesmall intestine can easily be exteriorised from the ab-dominal cavity by gentle pressure on the wound edg-es and manual delivery of the intestine. Anatomic-pathological findings will determine the operativeprocedure.

Steps in the operative procedures are:� Identification of pathological type and possible

aetiology.� Confirmation of patency of distal small and large

bowel with saline injection (patency of the coloncould have been demonstrated by contrast enemaprior to surgery).

� Resection of the proximal bulbous atretic segment.� Volvulated bowel must be untwisted carefully, es-

pecially in type III(b) atresia.� Limited distal bowel resection.� Accurate measurement of residual bowel length

proximal and distal to the anastomosis.

� Single-layer end-to-end or end-to-back anastom-osis.

� Bowel lengthening procedures have no place dur-ing the initial surgery.

� Gastric decompression post-operatively is bestachieved with a Replogle tube on low continuoussuctioning. Neither decompression Stamm gas-trostomy nor transanastomotic feeding tubes arerecommended.

� The fashioning of proximal or distal stomas areonly indicated in the presence of established peri-tonitis, or with compromised vascularity of the re-maining intestine.

� Additional steps may include derotation of a prox-imal jejunal atresia, back resection to the distalsecond part of the duodenum and excision or in-version tapering of the duodenum if very dilated.Where total bowel length is significantly reduced(type III and type IV), the bulbous dilated seg-ment proximal to the atresia is conserved. As pro-grade peristalsis of this bowel is deficient the lu-men calibre should be reduced. Maximum muco-sal conservation is achieved by inversion plicationprior to anastomosis to the distal bowel.

Figure 22.5

� Detection of Distal Atretic Areas. It is imperativeto exclude distal atresia, which have a prevalence rateof 6–21%. This is best achieved with a preoperativebarium enema to exclude an associated colonic atre-sia and by injecting saline into the distal collapsedsmall bowel and following the fluid column distallyuntil it reaches the caecum.

� Bowel Length Measurement. The total length ofthe small bowel is measured along the antimesenter-ic border. Once bowel resection has been completed,residual bowel length is of prognostic significanceand may determine the method of reconstruction es-pecially in types III and IV atresia. The normal bow-el length at full term is approximately 250 cm and inthe premature infant it is 115–170 cm.

Chapter 22 Jejuno-ileal Atresia217

Figure 22.4

Ligament of Treitz

Figure 22.5

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Figure 22.6

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The atretic region and the adjacent distended proxi-mal and collapsed distal bowel are isolated with ster-ile moist swabs. The intestinal content is milkedbackwards into the stomach from where it is aspirat-ed and a bacteriology swab is sent for culture andsensitivity.Alternatively, proximal bowel contents aremilked into the bulbous blind end if it is to be resect-ed. An atraumatic bowel clamp is then placed acrossthe bowel a few centimetres proximal to the electedsite for transection.

If total bowel length is deemed of adequate length(>80 cm + ileocaecal valve) the bulbous hypertro-phied proximal bowel is resected (5–15 cm) alongsidethe mesenteric bowel border in order to preservemaximal mesentery for later use, until normal diam-eter bowel has been reached. The bowel should thenbe divided at right angles leaving an opening of ap-proximately 0.5–1.5 cm in width. The blood supplyshould be adequate to ensure a safe anastomosis.This is followed by very limited distal small bowel re-section over a length of 2–3 cm. The resection lineshould be slightly oblique towards the antimesenter-ic border to ensure that the openings of the proximal

and distal bowels are of approximately equal size tofacilitate easy axial or end-to-back (Denis-Browne)single-layer anastomosis. However, the discrepancyin luminal width of the proximal and distal bowelmay vary from 2–5 cm depending on the distancefrom the stomach.

With type III(b) or high jejunal atresia the proxi-mal bowel should be derotated and resection of thebulbous portion may be extended into the third orsecond part of the duodenum without jeopardizingthe ampulla of Vater. The distal “apple peel” compo-nent of Type III(b) atresia may require release of re-stricting bands along the free edge of the distallycoiled and narrow mesentery to avoid kinking andinterference with the blood supply. The large mesen-teric defect is usually left open but with proximalbowel resection the residual mesentery can be usedto obliterate the defect. Furthermore, to preventkinking of the marginal artery after completion ofthe anastomosis, the bowel needs to be replaced verycarefully into the peritoneal cavity in a position ofnon-rotation.

Figure 22.7, 22.8

The anastomosis is either end-to-end or end-to-back(Denis-Browne method); 5/0 or 6/0 absorbable sutu-res stitches are used. The mesenteric border of the di-vided ends is united with a stay suture and a match-ing stitch is placed at corresponding points of the

anti-mesenteric borders of the divided ends. The “an-terior” edges of the bowel are then united with inter-rupted through-and-through extramucosal stitches,which are tied on the serosal surface.

Chapter 22 Jejuno-ileal Atresia219

Figure 22.6

Figure 22.7 Figure 22.8

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Figure 22.9

After completion of one-half of the anastomosis thebowel is rotated through 180° and the “posterior”anastomosis completed. Alternatively the posterioredge of the bowel is anastomosed with the stitchestied on the mucosal surface followed by anastomosisof the “anterior” edges with interrupted stitches tiedon the serosal surface. The suture lines are inspectedfor anastomotic integrity or tested with saline injec-tion on completion.

Although isolated type I atresia is best dealt withby primary resection and anastomosis, multiple dia-phragms have been successfully perforated withtransluminal bougies being passed along the entirelength of the affected small bowel.

Multiple type IV atresias, present in 18% of in-fants, are often localized necessitating en-bloc resec-tion and a single anastomosis, rather than multipleanastomosis. It is important, however, to maintainmaximum bowel length to avoid the short bowel syn-drome.

Similar techniques are used for intestinal stenosisand type I atresias. Procedures such as simple trans-verse enteroplasties, excision of membranes, bypass-ing techniques or side-to-side anastomosis are nolonger utilized. They fail to remove the abnormaldysfunctional segments of intestine, thus increasingthe risk of the blind loop syndrome.

Figure 22.10

The defect in the mesentery is repaired by approxi-mating or overlapping the divided edges with inter-rupted sutures taking great care not to incorporateblood vessels or kinking the anastomosis. Closure ofthe large mesenteric defect can be facilitated by usingthe preserved mesentery of the resected proximalbowel.

� Wound Closure. The peritoneal cavity is thorough-ly irrigated with warm saline to remove all macro-scopic debris and the bowel then returned to the ab-dominal cavity. Care is taken not to kink the anas-tomosis. The abdomen is closed by approximating enmass all the layers of the abdominal wall, excludingScarpa’s fascia, with a single continuous 4/0 monofil-ament absorbable suture, followed by subcutaneousand subcuticular absorbable stitches. No drains ortrans-anastomotic tubes are used.

Chapter 22 Jejuno-ileal Atresia221

Figure 22.9

Figure 22.10

Heinz Rode, Alastair J.W. Millar222

Figure 22.11, 22.12

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Alterative surgical techniques may be required if theischaemic insult has resulted in an atresia with mark-edly reduced intestinal length, where large resectionsof abnormal or multiple atretic segments are re-quired or if the measured residual small intestinallength is <80 cm.

Indications for tapering are:� As part of bowel length preservation where the

proximal atretric segment is grossly dilated andhypertrophied over an extended distance – typicalin type III(b) atresia and high jejunal atresia

� To equalize disparity in anastomotic lumen size� For the correction of a failed inversion plication

procedure� To improve function in a persistently dilated non-

functioning mega-duodenum following surgeryfor upper jejunal atresia

� Tapering duodeno-jejunoplasty. This method isprimarily indicated to conserve bowel length (highjejunal atresia, type III(b) atresia) and to reduce dis-parity in anastomotic diameter size. The atretic jeju-noduodenum is derotated and the antimesentericsegment of the dilated proximal segment is resectedover a 22–24F catheter. The resection may extendcephalad to the second part of the duodenum. An in-testinal auto-stapling device may be used to facilitatethe resection and anastomosis. The longitudinalanastomotic line is reinforced with an absorbable 5/0or 6/0 Lambert suture. Tapering can safely be doneover a length of 20–35 cm. The tapered bowel is thenprimarily anastomosed to the distal bowel (with orwithout equal bowel diameters) and left in a depen-dant position as for corrected malrotation with thecaecum in the left hypochondrium.

Chapter 22 Jejuno-ileal Atresia223

Figure 22.11

Figure 22.12

Heinz Rode, Alastair J.W. Millar224

Figure 22.13, 22.14

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� Plication and Folding. The basic derotation andback resection methods are used as previously de-scribed for tapering procedures. The plication meth-od has the advantage of reducing the risk of leakingfrom the antimesenteric suture line, conserves mu-cosal surface area and may even facilitate return ofbowel peristalsis. More than half of the antimesen-teric bowel circumference may be infolded into thelumen over an extended length without causing an

obstruction with care being taken not to narrow thelumen excessively. The “keel” must be trimmed andclosed with interrupted sutures. The main drawbackof this method is unravelling of the suture line with-in a few months, necessitating revision. The bowel isleft in a position of derotation with the duodenojej-unum dependant, the mesentery broad based and thecaecum in the left hypochondrium.

Chapter 22 Jejuno-ileal Atresia225

Figure 22.13

Figure 22.14

Heinz Rode, Alastair J.W. Millar226

Figure 22.15–22.17

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� Antimesenteric Seromuscular Stripping and In-version Plication. This technique prevents unravell-ing of the plication method and preserves maximalmucosal surface for absorption. A single or two anti-mesenteric converging seromuscular strips ±2 mmin width are resected. This is easily performed by sta-bilizing the proposed line of resection with straightnon-toothed forceps. A seromuscular strip is then

excised taking care not to damage the mucosa. Thetwo denuded mucosal strips are then approximatedwith a running monofilament suture. The keel of theinverted bowel should be trimmed and bowel edgesapproximated with interrupted sutures prior toanastomosis to the distal bowel. Proximal and distalluminal size can be approximated to facilitate theanastomosis.

Chapter 22 Jejuno-ileal Atresia227

Figure 22.15

Figure 22.16 Figure 22.17

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CONCLUSION

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The overall survival amongst newborn babies withintestinal atresia has increased from a dismal 10% in1952 to 90% at present. This came about primarilyfrom a change in the surgical procedure from pri-mary anastomosis without resection to liberal resec-tion of the blind proximal and distal ends followed byend-to-end anastomosis.

Understanding the pathogenesis of atresia andadapting surgical procedures to minimize loss andconserve bowel length ensured that most infants willhave sufficient bowel length for normal alimentarytract function and overall growth and development.Despite improvement in surgery, anaesthesia andperi-intra- and post-operative care, type III(b) atre-sia still carries a mortality of 19% predominantly dueto gangrene of the proximal end of the distal segment(7%), anastomotic leak (15%) and stricture formation(15%). The prognosis of intestinal atresia is furtherdetermined by genetic factors, prematurity (30%),delay in presentation, associated diseases, i.e., cysticfibrosis, malrotation (45%), exomphalos, gastroschi-sis and Hirschsprung’s disease, together with othergastro-intestinal atresias, infarction of the proximalatresia with peritonitis, sepsis, pneumonia and thecomplications of prolonged parenteral nutrition.

The incidence of post-surgical complications suchas anastomotic leaks, stricture formation, transient

intestinal dysfunction, blind loop syndrome and theshort bowel syndrome can be minimized by carefulattention to the presenting anatomical detail, meticu-lous surgical technique and maximal bowel lengthconservation methods. Because of the high incidenceof unravelling, the plication technique is rarely used.

The short bowel syndrome is a major factor influ-encing outcome. It may be due to predisposing fac-tors such as extensive intra-uterine bowel loss, oper-ative factors, i.e., over-zealous bowel resection and is-chaemic injury to the bowel or post-operative com-plications. Under ideal circumstances a survival rateof 46–70% can be expected in most infants with lessthan 25 cm jejuno-ielum.

Several surgical procedures have been identifiedto improve the outcome of the short bowel syndromeincluding reversal of segments of bowel, interposi-tion of colonic segments and methods to increasemucosal surface area for absorption purposes. Mostare of experimental value only except for bowel-lengthening procedures. The latter should not beperformed initially until conservative methods tostimulate and allow maximum bowel adaptation tooccur, have failed. Full bowel adaptation may require6–18 months to become achieved.

SELECTED BIBLIOGRAPHY

Kling K, Applebaum H, Dunn J, Buchmiller T, Atkinson J(2000) A novel technique for correction of intestinal atresiaat the ligament of Treitz. J Pediatr Surg 35 : 353–356

Louw JH, Barnard CM (1955) Congenital intestinal atresia: ob-servations on its origin. Lancet 2 : 1065–1067

Malcynski J T, Shorter N A, Mooney D P (1994) The proximalmesenteric flap: a method for closing large mesenteric de-fects in jejunal atresia. J Pediatr Surg 29 : 1607–1608

Rode H, Millar AJW (2003) Intestinal atresia and stenosis: In:Puri P (ed) Newborn surgery. Arnold, London, pp 445–456

Weber TR, Wane DW, Grosfeld JL (1982) Tapering enteroplastyin infants with bowel atresia and short bowel syndrome.Arch Surg 117 : 684–688