Objectives: Vitamin B(12) deficiency is an important long-term problem after urinary diversion using an intestinal segment. In this study, we examined serum vitamin B(12) concentrations in patients with neobladders constructed from various intestinal segments to determine the anatomic factors important for avoiding vitamin B(12) deficiency.
Methods: Twenty-two patients (19 men and 3 women) had an ileal neobladder (modified Studer type); 9 men had an ascending colonic neobladder (Goldwasser type); 30 patients (24 men and 6 women) had a sigmoid neobladder (modified Reddy type); and 18 (15 men and 3 women) had an ileocolic neobladder (Mainz type). The postoperative follow-up ranged from 3 months to 11 years (mean +/- SD, 3.4 +/- 2.8 years). The serum vitamin B(12) concentration was determined at several points after surgery.
Results: No patient with a neobladder fashioned from ascending or sigmoid colon developed a low vitamin B(12) concentration. Of the 18 patients with an ileocolic neobladder, 3 (16.6%) developed decreased serum vitamin B(12) concentrations after 5 to 6 years. Of the 22 patients with an ileal neobladder, 3 (13.6%) developed a low serum concentration of vitamin B(12) between 9 months and 3 years after surgery. No patient developed megaloblastic anemia or neurologic symptoms.
Conclusions: Preservation of the terminal 15 cm of ileum is not sufficient to ensure adequate vitamin B(12) absorption, and thus, preserving the ileal length is important. Use of colonic segments to construct neobladders appears to be preferable to ileal segments to preserve vitamin B(12) absorption.