Endoluminal Ultrasonographic and Histologic Evaluation of Periurethral Collagen Injection

To determine the acute and chronic ultrasonographic and histologic characteristics of injected glutaraldehyde cross-linked collagen in an animal model in order to enhance the therapeutic efficacy of the delivery of collagen for the treatment of urinary incontinence, three different depths of endoluminal ultrasound-guided injection (submucosal, intramuscular, periadventitial) of collagen into the urethral and bladder walls in two Yucatan mini pigs were investigated. The ultrasonographic characteristics of the injected material were examined 1,4,8, and 12 weeks later. A separate set of collagen injections, into the dermis and intramuscular layer of the lateral thigh of the animals, was undertaken with small-parts ultrasound guidance and follow-up. The injected tissues of the bladder, urethra, and thigh were ultrasonographically and histologically examined 3 months post-injection. Acutely injected collagen appeared hypoechoic on ultrasonography, although echogenicity increased over time. Submucosally injecte...