Purpose: The purpose of this report is to investigate changes in the myenteric plexus associated with the dilated proximal segment of jejunoileal atresia (JA). Two-dimensional morphologic changes in the myenteric nerve plexuses were investigated using whole-mount preparation.
Methods: Proximal (P) and distal (D) intestinal segments from 7 cases with JA and control (C) segments from 5 postmortem neonates were investigated. The circumference of the jejunoileal segments was measured after fixation. Antibodies for protein gene product 9.5 and neurofilament protein were used in whole-mount preparation. The sizes of neural networks were calculated by measuring the longest circular distance in a neural network (x) and the longest longitudinal distance (y), and the width of the internodal strands (i) with a videomicrometer.
Results: Median circumference of the segments was 8.5 in P, 2.0 in D, and 2.0 cm in C. The neural networks in P were expanded longitudinally as well as circularly (x = 817.10 microm, y = 561.26, i = 31.04: median) while comparing them to those in D (x = 431.40 microm y = 288.07, i = 26.05) or C (x = 285.03 microm y = 372.20, c = 1113.57, i = 32.39). The nerve plexus was less expanded than the intestinal wall.
Conclusions: Proximal intestinal segments showed a restructuring that resulted in mild hypoplasia of the enteric nerve plexuses in the proximal segments. The less expansion of the myenteric nerve plexus seen in the proximal bowel in infants with JA suggests a histologic basis for the efficacy of tapering or plication of the dilated bowel.