Better understanding of the long-term delivery of parenteral nutrition (PN) in neonates and children has increased the survival for patients who have neonatal short bowel syndrome. Most infants with short bowel syndrome experience progressive enteral adaptation and are weaned from PN. This report describes the authors' clinical experience with nine infants and children who had refractory short bowel syndrome; single or sequential procedures were performed to lengthen the small bowel. Gut lengthening procedures used included a small bowel nipple valve constructed distally, to provide temporary partial obstruction and thereby induce dilatation and lengthening of the proximal small intestine (six patients). Bianchi's technique was used in three patients primarily and in six others after the bowel had been dilated and lengthened by the nipple valve. Kimura's gut lengthening technique was used in one patient after the small bowel had spontaneously become dilated subsequent to a Bianchi procedure. In all, 16 lengthening procedures were performed on the nine patients. Preoperatively, the nine patients tolerated less than 10% of their caloric intake enterally, with no evidence of improvement for a minimum of 6 months. Small bowel segments ranged from 6 to 92 cm originally and were increased an average of 2 1/2 times the original length. Two patients have been totally weaned from PN. For the patients whose lengthening procedure was performed more than 1 year ago, the percentage of enteral caloric intake averages 50%. One of the patients was profoundly impaired neurologically and was not resuscitated from an apneic episode. Another patient died in his sleep of unknown causes 1 year after intestinal lengthening.(ABSTRACT TRUNCATED AT 250 WORDS)