Three laparotomies later: extrinsic duodenal atresia from malrotation complicated by intrinsic duodenal and pyloric windsock webs

Introduction

Atresia implies absence of formation or complete encroachment of a lumen making it unusable. Stenosis implies partial encroachment of a lumen with decreased usage [1], [2].

Intestinal atresia and stenosis can result from intrinsic factors such as lack of formation or failure to re-canalize the solid cord of embryonic cells during gestational weeks 5–8, persisting as diaphragms or webs with varying degrees of luminal obstruction [1]. The degree and onset of symptoms depend on the presence or absence of perforations or fenestrations of these membranes.

Extrinsic factors include compressive forces from either constricting peritoneal bands (Ladd bands), as found in malrotation, or with an annular pancreas or a preduodenal portal vein (PDPV) [1], [3], [4]. A windsock anomaly is a thin intraluminal web, which can prolapse distally inside the intestinal lumen along its axis due to peristalsis [4], [5].

Congenital pyloric obstruction is rare and occurs at an incidence of 0.003% [4]. It is caused by pyloric webs in two out of three cases, pyloric atresia in 25% of cases and the remaining from antral webs and rarely intrapyloric ectopic pancreatic tissue [5]. Antral or pyloric webs cause non-bilious emesis due to their pre-ampullary location while congenital duodenal obstructions below the ampulla of Vater cause bilious emesis.

Congenital duodenal obstruction has an incidence of 1:10,000 [4]. Intrinsic etiologies include duodenal webs (type I duodenal atresia) and duodenal atresia (type II in the form of a fibrous cord and type III with complete discontinuity). Duodenal webs occur in the 2^nd part of the duodenum and thus distal to the ampulla of Vater in 70–85% of cases, while 15–30% occur proximally [4].

Intrinsic congenital duodenal obstruction is associated with trisomy 21 in 30% of cases and with rotational anomalies such as malrotation in 20–30% and annular pancreas in 20%. Direct extrinsic compression of the lumen can also result from Ladd bands due to malrotation, an annular pancreas or a PDPV [1], [4].

Finally, ileal-and jejunal atresias are caused primarily by vascular compromise of a local intestinal segment rather than from failure of re-canalization [1] (Table 1).

The terms atresia vs. stenosis are often used clinically more than morphologically to stress the degree of luminal obstruction (Figure 1).

Figure 1:

Congenital small bowel obstruction.

PDPV = preduodenal portal vein.

Case presentation

An appropriate-for-gestational age female infant weighting 3275 g and born by vaginal delivery at 39 + 6/7 weeks to a 28-year-old gravida 2 para 2 Caucasian woman whose pregnancy was uncomplicated, presented to a local emergency room at 5 days of age with a 2-days’ history of gradually more frequent and voluminous emesis that had now also become bilious.

The infant had been stooling normally. An abdominal ultrasound to rule out pyloric stenosis was normal. An abdominal radiograph showed a central dilated bowel loop but the abdomen was otherwise gasless. An Orogastric tube was placed and 30–40 mL of bilious fluid was aspirated from the stomach. An upper gastrointestinal series (UGI) with Gastrograffin revealed obstruction of the first part of the duodenum with no further passage of contrast (Figure 2). An emergent laparotomy revealed malrotation with Ladd bands emanating from the right colon toward the retroperitoneum and completely compressing and obstructing the duodenum. The duodenum proximal to the obstruction was dilated and the distal jejunum was small and unused but otherwise structurally normal. A Ladd procedure was performed and since no bowel resection was required, an enterotomy was not indicated.

Figure 2:

Initial UGI reveals a distal gastric outlet or duodenal obstruction.

The infant was subsequently passing pigmented stools intermittently but also continued to have bilious emesis. Abdominal radiographs continued to show a distended stomach and absence of distal air. Erythromycin was started for prokinesis but the infant continued to have intermittent bilious emesis and up to 200 mL/day of bilious output from the orogastric tube. A repeat UGI study on day of life (DOL) 32 showed delayed passage of contrast past the second part of the duodenum. A duodenal web was therefore suspected and a second exploratory laparotomy was performed on DOL 39. A longitudinal incision was made in the distal duodenum and a feeding catheter was unable to be passed into the proximal jejunum. A windsock duodenal web with pinhole opening was noted, and therefore, a proximal duodeno- to proximal jejunostomy was created to bypass the distal duodenal web.

Over the next 10 days the infant continued to have large bilious output from the orogastric tube and occasional emesis but she also continued to intermittently pass pigmented stools. A third UGI study on DOL 49 was still suggestive of a stenosis of the distal duodenum: Contrast readily filled the proximal second part but delayed images failed to demonstrate progression past the mid-distal second portion of the duodenum (Figure 3). Therefore, a third laparotomy with the intention of exploring and revising the original anastomosis and placing a gastro-jejunal feeding tube was performed on DOL 56.

Figure 3:

The third UGI study showed contrast filling the proximal second portion of the duodenum. Delayed image (figure) shows stenosis of the mid-distal second portion of the duodenum.

During this third laparotomy the duodenojejunostomy anastomosis was found to be widely patent, however, retrograde instrumentation through the pylorus now revealed an additional obstruction. Extension of the duodenotomy through the pylorus confirmed the presence of a windsock pyloric web, which was incised and a gastrojejunostomy (GJ) feeding tube was subsequently placed.

Following the procedure, feedings were resumed through the GJ tube and the erythromycin was continued. The infant subsequently tolerated feedings and was gradually transitioned to oral feedings and the GJ tube was removed on DOL 86.

Discussion

This infant had congenital duodenal obstruction resulting from the unusual combination of both extrinsic factors (constricting Ladd bands from malrotation) and two intrinsic factors (a duodenal and a pyloric web).

Previous case reports have described intrinsic duodenal atresia in combination with an antral web [6] and obstruction due to double duodenal webs [7]. Combinations of both intrinsic and extrinsic duodenal lesions have also been reported and include malrotation plus a duodenal web [8], [9], malrotation plus both a PDPV and a duodenal web [10] and the combination of a duodenal web and a duodenal stenosis [11]. Intestinal obstruction from multiple jejunal webs has also been reported [12], [13].

We are not aware of any reports describing the simultaneous occurrence of a gastric web and malrotation or the simultaneous occurrence of a pyloric and a duodenal web. This patient is therefore unusual in that she had malrotation with extrinsic compression of the duodenum from Ladd bands in addition to both duodenal and pyloric windsock webs also causing intrinsic obstruction.

The incidence of combination defects range between 6.7 and 20% [14], [15], [16] and they cause 10–58% of all reoperations in congenital duodenal obstruction [14], [15]. In a retrospective study of 298 patients with congenital duodenal obstruction, 20 (6.7%) had combinations of defects, 12 of these (60%) required reoperations and in seven of these 12 (58%) reoperations were for undetected additional lesions (malrotation with a duodenal web or multiple duodenal webs) [15]. In another retrospective cohort of 138 infants where 20% had combination defects, 10% of all reoperations were due to additional atresias [14].

Intestinal webs are difficult to diagnose with radiographs as fenestrations can allow for contrast to pool on both sides of the membrane. An undiagnosed proximal windsock web can prolapse forward from the pressure of a peristaltic wave or contrast medium and mimic an obstruction further distally. This was likely the case when the pyloric windsock web on the third UGI study suggested obstruction near the site of the duodenojejunostomy that later was found to be patent (Figure 3).

Absence of malrotation at laparotomy and either an annular pancreas, a normal caliber duodenum or an atretic duodenal segment are all likely to trigger some sort of duodenotomy with the opportunity to instrument the duodenal lumen both proximally and distally. Antral webs are generally treated by simple excision, pyloric webs by pyloroplasty, and intrinsic duodenal obstruction as well as an annular pancreas by either a duodenoduodenostomy or a duodenojejunostomy. A Ladd procedure however, does not require an enterotomy [1], [4]. This creates somewhat of a dilemma for the pediatric surgeon: Either assume that the malrotation was the sole explanation to the duodenal obstruction and risk the later need for a reoperation due to undetected webs, or perform a potentially unnecessary enterotomy preemptively and risk additional complications.

Pyloric webs are extremely unusual (0.003%) but it is important to at least consider instrumenting the intestine in both antegrade as well as in retrograde directions when performing a Ladd procedure or repair of a duodenal atresia or a stenosis, in order to avoid the need for a potential repeat laparotomy [6], [15], [16].

However, given the potential complications associated with an enterotomy, we feel that a reasonable time period of expectant management following a Ladd procedure is reasonably warranted before full return of small bowel function can be expected. During or following this time period, a trial of a prokinetic such as erythromycin can be considered.

Feitz and Vos described a retrospective pediatric cohort having undergone a Ladd procedure due to malrotation and found that postoperative nasogastric tube decompression was necessary for an average period of 6.7 days (median 6 days, range 1.5–16 days) in infants [17].

For this reason we think it is reasonable to expect at least 1 week of postoperative bowel dysfunction following an uncomplicated Ladd procedure for malrotation. Erythromycin, a motilin agonist, has been demonstrated to increase proximal gastric tone, the strength and frequency of antral and proximal small bowel contractions as well as reducing pyloric outlet resistance [18]. Infants with postoperative dysmotility after repair of gastrointestinal anomalies have been reported to reach full enteral feedings after 2–3 weeks of erythromycin therapy [19], [20]. Performing a repeat UGI too early likely yields falsely abnormal results as a functional obstruction due to postoperative bowel dysfunction can mimic a partially fenestrated windsock just as a windsock can mimic a more distal obstruction as occurred in our patient.

Therefore, in order to avoid unnecessary and premature reoperations we recommend that following a 1–2-week long period of expectant management with or without erythromycin, additional, however more unusual etiologies must be sought. Subsequent to this unusual case, an algorithm describing our recommended approach to duodenal obstruction is presented in Figure 4.

Figure 4:

Suggested algorithm for the diagnosis and management of duodenal obstruction.