While the serial transverse enteroplasty (STEP) procedure has been considered a major advance in the management of short bowel syndrome (SBS), long-term data are in short supply.  5-year outcomes from Toronto with regard to 12 patients offers some insight into the effectiveness of this operation (J Pediatr Surg 2012; 47: 931-37).

The 12 patients selected for this study received STEP prior to January 2005.  The other 19 STEP patients at this institution were not included due to lack of long-term followup. Among the 12 patients, 6 had intestinal atresia, 3 had NEC, 1 had gastroschisis, 1 had volvulus, and 1 had Hirschsprung disease.

Key results:

• 7 patients weaned off parenteral nutrition successfully –one took 4 years; one patient continued on parenteral nutrition.
• 2 patients died of liver failure, 2 patients received liver-intestinal transplant.
• STEP increased small bowel length from a median of 110 cm to 128 cm.  The dilated portion that received STEP changed from a median length of 31 cm to a median of 57 cm; this resulted in a median bowel caliber change from 6 cm to 2 cm.  The overall effect was an overall increase in small bowel length of 40%.
• Biochemical markers improved.  For example, citrulline increased from 18 μmol/L pre-STEP to 33 μmol/L at 12 months, and 48 μmol/L at 5 years post-STEP.  Fecal fat malabsorption (based on 72 hr collections) improved from >40% to ~20% 6 months after STEP.
• Indications for STEP: bacterial overgrowth (n=7), intestinal failure associated liver disease (IFALD) (n=5).
• Complications: suture line bleeding due to ulcerations in one patient, 2 patients had leakage at suture line in immediate post-op period.  The latter 2 cases were ascribed to limited experience with technique; the surgeons now use a 2.5 mm staple instead of a 3.5 mm.

Take home points:

1. Authors comment: “our approach is to only consider patients who plateau in their parenteral nutrition weaning or develop complications such as PN cholestasis…patients who continue to show intestinal adaptation are not offered surgery despite the presence of bowel dilatation”
2. “It takes up to an average of 1 to 2 years to see the improvement in intestinal function after a STEP.”  While the authors may be correct about this timeframe, in their figure 3, two came off PN at one month post-STEP, four achieved this goal 6 months after STEP and another 12 months following STEP.
3. Why does STEP work? Either improved intestinal function due to increased absorptive surface or due to healing of existing mucosa; the latter may occur with resolution of dilated,  inflamed bowel associated with bacterial overgrowth.

Related blog entries:

Four advances for intestinal failure | gutsandgrowth

IFfy outcome | gutsandgrowth

Additional STEP references:

• -JPGN 2007; 45: 174, 257.
• -J Pediatr Surg 2003; 38: 425-429. Initial description of STEP procedure from Kim HB et al.
• -Clin Gastro & Hep 2006; 4: 1237. STEP in 4 patients helped to decrease or eliminate TPN requirements.
• Images for step procedure