Type 1 Dolichocolon as a Potential Anatomic Co-Morbidity in Pediatric Perianal Crohn's Disease.

Background: Perianal Crohn's disease (PCD) represents one of the most severe and refractory forms of pediatric inflammatory bowel disease (IBD). Constipation and colonic redundancy, particularly type 1 dolichocolon (T1-DC), may increase distal rectosigmoid pressure, and exacerbate perianal pathology. We hypothesized that T1-DC is more common in children with PCD than in those with uncomplicated ileocolonic Crohn's disease (CD) or non-IBD controls. Methods: We retrospectively analyzed 20 consecutive pediatric PCD cases (penetrating [B3p] or inflammatory [B1p]) and compared them with 20 patients with non-complicated ileocolonic CD (L3/B1) and 30 non-IBD trauma controls. DC type was determined radiographically using established criteria, focusing on T1- and T2-DC. Constipation history was abstracted from medical records under IRB-approved protocols. Results: DC was significantly more prevalent in PCD than in ileocolonic CD or controls (p < 0.001), primarily due to T1-DC. The associations persisted (p<0.03) in PCD patients without a history of constipation. Conclusions: Rectosigmoid redundancy (T1-DC) may represent an underrecognized anatomic co-morbidity in pediatric PCD, contributing to increased distal pressure and susceptibility to perianal complications. Identification of T1-DC could inform surgical decision-making and postoperative management. Targeted approaches-such as segmental resection during stoma reversal, structured bowel regimens, physical activity, and pelvic-floor biofeedback-may help reduce recurrence risk. Prospective studies are needed to define the mechanistic role of colonic redundancy in the pathogenesis of PCD.