title: Calcification of glutaraldehyde cross-linked collagen in bladder neck injections in children with incontinence: a long-term complication.
abstract: OBJECTIVE
  We report the incidence of calcifications developing at the bladder neck/urethra in pediatric patients treated with glutaraldehyde cross-linked collagen for urinary incontinence.
  
  
  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.
authors.affiliation: Division of Pediatric Urology, Department of Urology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Knudson
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Cooper
authors.forename: Craig A
authors.initials: CA
authors.lastname: Block
authors.forename: Charles E
authors.initials: CE
authors.lastname: Hawtrey
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Austin
mesh_terms: D000293:Adolescent; D002114:Calcinosis / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D003094:Collagen / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007267:Injections; D008297:Male; D019736:Prostheses and Implants / Q000009:adverse effects*; D012189:Retrospective Studies; D013997:Time Factors; D001745:Urinary Bladder Diseases / Q000209:etiology*; D014549:Urinary Incontinence / Q000628:therapy*
chemical_list: C048470:glutaraldehyde-cross-linked collagen; D003094:Collagen