BONE METABOLISM FOLLOWING BLADDER SUBSTITUTION WITH THE ILEAL URETHRAL KOCK RESERVOIR

Objectives To assess bone metabolism following bladder substitution wi th the ileal Kock reservoir. Patients, subjects and methods The invest igation comprised two separate studies, one with baseline measurements before and after surgery, and the second after surgery only, of bone mass, made using single-photon absorptiometry and dual-energy X-ray ab sorptiometry, biochemical variables of bone turnover, plasma analyses and measurements of renal calcium and phosphate excretion. After inclu sion, both groups of patients were observed longitudinally for 2 years . The post-surgery study included 25 patients who had undergone bladde r substitution (median age 67 years, range 44-75), with a median post- operative follow-up of 1.0 year (range 0.3-3.7), and 16 control subjec ts (either healthy or with other minor urological complaints; median a ge 62 years, range 34-80), and the pre-surgery study comprised seven p atients who had undergone bladder substitution (median age 57 years, r ange 42-68). Results Total body, forearm and spinal bone mineral conte nts were similar in patients with an ileal bladder substitute measured 1 year after surgery and in control subjects. There were equivalent s ignificant changes in both the patients and control subjects during th e 2-year observation period, with a 2-3% decrease in total body and fo rearm bone mineral content. The values were similar in patients with a nd without a mild metabolic acidosis. Plasma calcium, phosphate, total alkaline phosphatase, intact parathyroid hormone, vitamin D and osteo calcin were normal in both patients and control subjects. Renal excret ion of calcium and phosphate was also similar in patients and in contr ol subjects. Conclusions Ileal urethral Kock bladder substitution does not lead to accelerated bone mineral loss in elderly men, despite a m ild metabolic acidosis in half of the patients.