Lengthening the small bowel in patients with short gut syndrome is a challenging task. In 1980 Bianchi (1) described the longitudinal intestinal lengthening and tailoring (LILT) procedure that takes advantage of the unique split anatomy of the small intestinal mesenteric blood supply. Despite its creative elegance, Bianchi's operation can be technically demanding. In 2003 Kim et al (2,3) proposed the serial transverse enteroplasty (STEP) procedure for patients with shortened dilated bowel. In contrast to Bianchi's LILT, the STEP procedure is technically easier to perform with use of standard surgical staplers and is less likely to damage the blood supply to the already compromised small bowel.
The STEP was originally described in children with longstanding dilated small bowel or in children who had already undergone LILT. This attractive option may have application in other scenarios such as in the setting of small intestinal atresia with significant loss of small bowel length. We describe our use of the STEP procedure in a newborn patient with gastroschisis complicated by proximal intestinal atresia and discuss it in the context of the other available cases in the literature.
A newborn girl, 35 weeks' gestation, was born by spontaneous vaginal delivery and was known to have gastroschisis and dilated intraabdominal bowel by prenatal ultrasonography. After delivery, the baby was taken to the operating room. A proximal jejunal atresia was identified and the bowel that had herniated through the gastroschisis defect was clearly nonviable, with no evidence of a pulse in its mesentery. This nonviable bowel was resected and the gastroschisis defect was closed with the 20 cm of dilated proximal jejunum left in situ within the abdomen. Distally, the middle and distal jejunum, ileum, ascending colon, and proximal transverse colon were absent. She was returned to the operating room electively 3 weeks later when the abdomen was reopened and the dilated jejunum was subjected to STEP (Fig. 1), increasing its length from 20 cm to 35 cm. Because no cecum or ascending colon remained, an anastomosis between the jejunum and transverse colon was created at this point. Postoperatively, she was maintained on parenteral nutrition (PN) until enteral feedings could be advanced. At age 9 months, she tolerated 40% of her energy intake enterally with the remaining energy units given parenterally. By 16 months of age, her tolerance of enteral nutrition had deteriorated and she had recurrent catheter infections. Despite this, her liver function test results showed normalization of albumin and total bilirubin levels (Table 1). She continues to grow and remains a viable candidate for intestinal transplantation.
Recent reviews on short bowel syndrome suggest that patients with <35 cm of small intestine are at greatest risk for requiring long-term PN and therefore are at greatest risk for PN-related liver damage, although PN independence has been reported in children with as little as 10 cm of remaining intestine (4–6). Due to these types of reports, it appears impossible to predict with certainty which patients ultimately become independent of PN or are destined for bowel transplantation. Therefore, maximizing the function of any remaining bowel, despite its extremely short length, should be an important goal of any multidisciplinary treatment strategy for intestinal failure.
The STEP procedure is a novel intestinal lengthening procedure described by Kim et al in 2003 (2) and is a potentially important new tool in caring for patients with intestinal failure. These authors first validated the STEP technique in experimental animals and a subsequent report detailed their first experience with the STEP operation in a 23-month-old child who had previously undergone a Bianchi procedure (3). More recently, there have been 3 separate reports describing the use of the STEP procedure in the neonatal period (7–9). The clinical details of these cases and of our case are reviewed in Table 2. All 4 cases involve intestinal atresia with dilated proximal bowel of varying lengths. However, in 2 of the 3 previously reported cases, the initial total small bowel length was reported to be significant at the outset (50 and 90 cm) and the ileocecal valve was present, improving their chances of weaning from PN. In our case the initial total small bowel length was 20 cm and the ileocecal valve was absent. As may be predicted, the 2 children reported with greater initial bowel length and an intact ileocecal valve were able to wean from PN without much difficulty within 45 days (7,8). In these cases the STEP provided a mechanism for effective intestinal tapering without any bowel loss. Although it is not surprising that our patient continues to require a significant portion of her energy intake parenterally, the STEP may have allowed for her enteral feeding regimen to be maximized early in her course, thereby providing some protection from PN-associated liver injury and normalization of her liver function.
Despite the diagnosis of gastroschisis in our patient, the atretic proximal segment of intestine was relatively normal and remained completely within the abdominal cavity during gestation, making the STEP procedure technically feasible. Some authors have recommended that a Bianchi procedure be performed before a STEP procedure. In this case it was believed that the dilated bowel was too short and too close to the duodenum, making the Bianchi procedure nearly impossible.
Initial reports on the effectiveness of the STEP have been published. Javid et al (9) reviewed the outcome of 5 children who underwent STEP in whom the mean preoperative bowel length was 61 cm. At an average follow-up time of 17 months, 1 child (20%) was able to completely wean from PN, with 2 others showing improved enteral tolerance. Another study by Sudan et al (10) reviewed the surgical treatment of intestinal failure at their institution. Of their 50 patients, 8 underwent a STEP procedure starting with a preoperative bowel length of 62 cm. With an average follow-up time of 2 years, 50% of patients who underwent a STEP procedure were able to wean from PN. Neither study discusses the problem of small bowel redilation after STEP. In the present case the bowel redilated by 15 months (Fig. 2), and this was temporally associated with worsening enteral tolerance. This redilation after STEP parallels what was found during the initial animal experiments that described the STEP procedure (2).
The initial bowel length in our case was shorter than in any child reported in either of these 2 studies (9,10) and the jejunum was markedly dilated, making PN dependence or intestinal transplantation likely outcomes based on bowel length alone. Although our patient remains at risk for long-term PN dependence, it is possible that the early application of the STEP procedure resulted in increased effective small bowel surface area, improved tolerance of enteral nutrition, and incomplete or diminished dependence on PN. She remains a viable candidate for small bowel transplantation and continues to be at risk for catheter-related infections; however, it appears that the ability to maximize her enteral feedings early may have significantly delayed the onset of severe cholestatic liver disease.
As evidenced by the cases reviewed here, the STEP procedure is technically feasible during the newborn period even when associated with gastroschisis. Intestinal lengthening procedures such at STEP should be considered in the newborn patient with congenitally dilated bowel, especially when the bowel length is congenitally short. Children with longer remaining lengths of bowel will predictably have a shorter duration of PN dependence. We would discourage the application of STEP in children with dilated bowel but intact or nearly normal bowel length, in whom a less challenging tapering enteroplasty could be applied.
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