Urinary diversion by the Kock ileal reservoir. Studies on clinical outcome, quality of life, bile acid and vitamin B12 metabolism

Abstract

Introduction: Urinary diversion with the Kock ileal reservoir has been performed at Sahlgrenska University Hospital since 1975. One key question is the long-term consequences regarding glomerular filtration rate (GFR) and quality of life of this kind of surgery. Other important topics are the consequences due to loss of ileum.Aims of the study: To analyze the long-term clinical outcome and impact on quality of life in patients with a Kock ileal reservoir. To determine the influence on GFR, bile acid metabolism and bowel habits. To analyze the influence on vitamin B12 metabolism. To develop a method for in vitro determination of bile acid uptake in intestinal mucosa and to determine the site of this uptake. Patients: 176 patients operated on during the period 1975-1999 were included in the study. 122 patients were alive at the time of follow-up. Sub-groups of patients were investigated with regard to quality of life (QOL), bowel habits, bile acid and vitamin B12 metabolism. In vitro mucosal biopsies were obtained at endoscopy or open surgery in patients without known bowel dysfunction. Methods: 70 cm of the distal ileum was used for the creation of the continent reservoir. QOL was assessed with SF-36 and OAS, GFR with chrom-EDTA-clearance, bile acid absorption with the SeHCAT retention test and vitamin B12 uptake with the standard Schilling test. Bile acid uptake in mucosal biopsies was determined using in vitro incubation techniques in forceps biopsies obtained from different parts of the bowel. Results: 90% have a reservoir that functions well. The health status is influenced more by the underlying disease than by the fact that the patient has a continent reservoir. Patients operated for benign functional or inflammatory disease seem to adapt less well to a life with ostomy. Renal function is not impaired by the continent urinary diversion. Most patients have fairly normal bowel habits. One-third of the patients develop post-operative bile acid malabsorption and some patients have severe problems with diarrhoea due to this malabsorption. Continent urinary diversion does not in itself lead to vitamin B12 deficiency. 10% of the patients develop true vitamin B12 deficiency. Substitution is advisable when serum levels of vitamin B12 are below 200 pmol/l. Bile acid uptake in human intestine can be measured with small mucosal biopsies obtained during colonoscopy or open surgery. Bile acids are not only absorbed in the distal ileum but also to a considerable degree 100 cm proximal to the ileocaecal valve. Conclusions: The long-term functional result of continent urinary diversion with a Kock ileal reservoir is good. Patient acceptance is high, and the quality of life is influenced more by the underlying disease. Resection of 70 cm of the distal ileum impairs bile acid absorption. The operation does not per se lead to vitamin B12 deficiency. The Kock ileal reservoir retains its place in the therapeutic arsenal. Small mucosal biopsies can be used for the evaluation of the bile acid uptake in patients with various conditions. Key words: Kock reservoir, urinary diversion, quality of life, bile acids, vitamin B12.