Calcification of Glutaraldehyde Cross-Linked Collagen in Bladder Neck Injections in Children With Incontinence: A Long-Term Complication

Purpose: We report the incidence of calcifications developing at the bladder neck/urethra in pediatric patients treated with glutaraldehyde cross-linked collagen for urinary incontinence. Materials and Methods: We reviewed charts of patients treated with glutaraldehyde cross-linked collagen injections for urinary incontinence between 1994 and 1999. Etiology of incontinence, pertinent medical history, operative details and postoperative imaging were examined. Results: Of 31 patients 4 (13%) had development of submucosal calcifications in the bladder neck/urethra. All 4 patients had received multiple injections of glutaraldehyde cross-linked collagen for incontinence secondary to neurogenic bladder. The calcifications were confirmed surgically. Pathology reports available for 2 of 4 patients showed chronic inflammation without dysplasia or malignant changes. Mean followup was significantly different between calcified and noncalcified cases (10.3 vs 7.2 years, p = 0.009), as was total volume of collagen injected (21 vs 12 cc, p = 0.012). Mean time to diagnosis of calcifications was 8.8 years (range 7 to 11) after first injection. A total of 24 patients without calcification underwent bladder imaging at a mean of 6.8 years (±2.2) after glutaraldehyde cross-linked collagen injection, which was not significantly different than the time to diagnosis (p = 0.089). The number of injections was not significantly different between the 2 groups (p = 0.426). Conclusions: Of our patients 13% had development of calcifications at the site of prior glutaraldehyde cross-linked collagen injections for incontinence. These calcifications were surrounded by chronic inflammation. Patients who have undergone glutaraldehyde cross-linked collagen injections may benefit from long-term followup with bladder imaging to detect and follow calcifications at prior injection sites.