NO EVIDENCE OF OSTEOPENIA 5 TO 8 YEARS AFTER ILEAL ORTHOTOPIC BLADDERSUBSTITUTION

Purpose: The use of bowel segments as bladder substitutes may result i n chronic, impaired vitamin D and calcium metabolism, and ultimately i n bone demineralization. Materials and Methods: Bone metabolism was ex amined in 14 patients who lived for 5 to 8 years with an ileal low pre ssure bladder substitute after radical cystectomy for bladder cancer. Bone mineral density was measured using dual energy x-ray absorptiomet ry of the total skeleton, lumbar spine, femoral neck, and tibial epiph ysis and diaphysis. Laboratory studies included serum levels of 1,25-d ihydroxyvitamin D, 25-hydroxyvitamin D, intact parathyroid hormone, pl asma alkaline phosphatase, electrolytes, creatinine and blood gas anal ysis. Results: Bone mineral density was normal in all patients. There was no evidence of deficient vitamin D stores. There was a tendency to ward slightly elevated serum creatinine values in patients with preexi sting impaired renal function, including 1 who also had slight acidosi s. No patient had hyperchloremia. Conclusions: We found no evidence of osteomalacia, osteoporosis or significant metabolic acidosis in 14 pa tients with an ileal bladder substitute for 5 to 8 years. However, it is not known whether the absence of osteopenia would also apply to pat ients with poor renal function, to those not followed meticulously and , thus, at risk for major long-term functional or metabolic disturbanc es from the ileal bladder substitute or to patients with orthotopic bl adder substitutes made from longer or other bowel segments than we use d.