Page 20 - 68 stomac-duodenum-&-small-intestine59-65_opt

Intestinal Atresia and Stenosis 387

At exploration, the site of the most proximal atresia is readily
identified as the site of marked change in intestinal calibre. 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 (Figure 63.4). 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 calibre
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.
After resection of the atretic segment, the surgeon is faced with
the difficult task of re-establishing 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. Therefore, in patients with a relatively short segment of Figure 63.4: Type I jejunal atresia. Membrane occlusion without mesenteric
severely dilated proximal intestine, resection of the dilated segment defect or loss of intestinal length.
with re-establishment of continuity by end-to-end anastomosis is a
good option. However, 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 frequently are treated by either imbrication or tapering
enteroplasty of the proximal dilated segment. To date, no randomized
studies have compared the outcomes for patients with intestinal atresias
with or without the addition of an enteroplasty or plication. In patients
for whom the atresia is just distal to the duodenojejunal flexure, it
may be advantageous to resect the dilated bowel, derotate, and taper
the duodenum with primary anastomosis. This facilitates passage of a
transanastomotic feeding tube and early restoration of foregut function.
The total residual length of bowel should be measured with a tape and
recorded, as this gives some guidance as to prognosis.
Patients who have multiple atresias (type IV) or an apple-peel
deformity (type IIIb) present particularly challenging management
problems (Figures 63.5 and 63.6). These patients may require multiple
anastomoses and frequently will experience long-term delays in return Figure 63.5: Type IIIb atresia (apple peel deformity). Note proximal jejunal atresia,
of intestinal function. In addition, many of these patients will have short malrotation, and mesenteric defect with a single artery of supply from the middle and right
bowel syndrome due to inadequate residual intestinal length. In general, colic vessels with significant loss of intestinal length.
the formation of stomas is unnecessary and should be avoided because
dilated bowel does not reduce in caliber, and fluid and electrolyte losses
may be severe.
Postoperative Complications
The most common postoperative complication is a functional obstruc-
tion at the site of anastomosis. Unfortunately, this complication may be
due to the underlying intestinal dysmotility associated with this anoma-
ly and may not be preventable by changes in surgical technique. Other
less commonly observed complications include anastomotic leak and
adhesive obstructions. Obstructions due to missed distal unrecognized
atresias should not occur and can be prevented by proper evaluation at
the time of the initial operation.
Prognosis and Outcomes
Most patients with intestinal atresia do not have associated life-threat-
ening anomalies. Therefore, the primary factor that impacts mortality
is the ability to support the nutritional needs of the patient during the
postoperative period while awaiting adequate bowel function to allow
enteral alimentation. In centres where parenteral nutritional support is
feasible, these patients can be supported for prolonged periods of time
while awaiting gastrointestinal function. However, in centres without
these resources, patient mortality will be higher and primarily attribut-
able to malnutrition. The judicious use of nasojejunal or gastrostomy Figure 63.6: Type IIIb atresia with antenatal volvulus of the “apple peel” leading
to short bowel.
transanastomotic feeding tubes for enteral feeding may be life saving.