Determining the correct resection level in patients with Hirschsprung disease using contrast enema and full thickness biopsies: Can the diagnostic accuracy be improved by examining submucosal nerve fiber thickness?

Background: Intraoperative resection level in patients with Hirschsprung disease (HD) is determined by contrast enema, surgeon's intraoperative judgement and full thickness biopsy (FTB) identifying ganglia. This study aims to evaluate diagnostic accuracy of contrast enema and FTB in determination of resection level and whether this can be improved by measuring submucosal nerve fiber diameter. Methods: We retrospectively analyzed contrast enema and intraoperative FTBs obtained in our center, determining diagnostic accuracy for level of resection. Gold standard was pathological examination of resection specimen. Secondly, we matched transition zone pull-through (TZPT) patients with non-TZPT patients, based on age and length of resected bowel, to blindly compare nerve fibers diameters between two groups using group comparison. Results: From 2000–2021, 209 patients underwent HD surgery of whom 180 patients (138 males; median age at surgery: 13 weeks) with 18 TZPTs (10%) were included. Positive predictive value of contrast enema was 65.1%. No caliber change was found in patients with total colon aganglionosis (TCA). Negative predictive value of surgeon's intraoperative judgement and FTB in determining resection level was 79.0% and 90.0% (91.2% single-stage, 84.4% two-stage surgery) respectively. Mean nerve fiber diameter in TZPT was 25.01 µm (SD= 5.63) and in non-TZPT 24.35 µm (SD= 6.75) (p = 0.813). Conclusion: Determination of resection level with combination of contrast enema, surgeon's intraoperative judgement and FTB results in sufficient diagnostic accuracy in patients with HD. If no caliber change is seen with contrast enema, TCA should be considered. Resection level or transition zone cannot be determined by assessment of submucosal nerve fiber diameter in FTB. Type of Study: clinical research paper.