Is Bone-wax an injectable urologic material?

Injection of endoscopic material for reflux and incontinence therapies became popular in urology because of its simplicity and repeatability. Research is going on to develop an ideal injectable material. In this experimental study we investigated whether the bone wax used for osteotomy hemostasis in orthopedic and neurosurgical operations could be used as an injectable material.

A total of 20 rabbits were included in the study: 6 underwent a sham operation, and in the remaining 14 rabbits, 0.5 ml bone wax liquefied with n-butyl acetic acid was injected submucosally via a 20-gauge needle at three different points on the anterior bladder wall. Cystectomy was performed on the 15th day in 2 rabbits (group I), on the 60th day in 2 (group II) and on the 150th day in 10 (group III). 0.20 ml bone wax was also injected subcutaneously and intramuscularly 7 days before cystectomy in group III. Bladders were examined macroscopically and histopathologically. All animals' lungs, livers, kidneys, spleens and brains were also removed and examined histologically.

Submucosal swellings of bone wax maintained their localizations and shapes in all groups and all of the 42 bone-wax injection sites could be easily identified. Histologically, slight edema around the implant was seen in group I. In group II, collagen was increased around the implants and minimal hyperplasia of the epithelium overlaying bone wax was noted. 150 days after the injections, moderate collagen production and a mild increase in vascularity were seen around the implants. There was no macroscopic or microscopic evidence that implants migrated to locations other than the injection sites.

When injected to the bladder submucosa, bone wax seems to be inert and biocompatible, encouraging further research to develop it as an alternative agent in the endoscopic treatment of vesicoureteral reflux and sphincteric incontinence.