Long-term assessment of serum vitamin B12 concentrations in patients with various types of orthotopic intestinal neobladder

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. UROLOGY 56: 236-240, 2000. (C) 2000, Elsevier Science Inc.