Ureteral segment replacement using a circumferential small-intestinal submucosa xenogenic graft.

We wished to determine whether small-intestinal submucosa (SIS) will epithelialize when used as a ureteral replacement material. An 11-mm segment of native ureter was excised from eight New Zealand White rabbits and replaced with an 11-mm porcine SIS graft, which was circumferentially wrapped around a ureteral stent. The SIS ureteral grafts were harvested at 11 days or 35 days postimplantation and examined grossly and by standard light microscopy techniques. Partial epithelialization with the ingrowth of urothelium, smooth muscle cells, and blood vessels was observed in the grafts harvested at 11 days postimplantation. The SIS ureteral grafts examined at 35 days postimplantation showed additional restructuring of the smooth muscle cell layer and more organized epithelialization in comparison to the SIS graft examined at 11 days. After 35 days of regenerative healing, elements of all three layers of the native ureter were observed within the collagen matrix of the SIS graft. No significant complications were observed, but all subjects (8/8) demonstrated mild intra-abdominal adhesions. Mild collecting system dilatations were observed in 4/4 (100%) of the animals harvested at 35 days and in 0/4 (0%) of the animals harvested at 11 days. We have this demonstrated in this preliminary study that SIS xenografts will epithelialize when used as a ureteral replacement material. The repair mechanism of these ureteral grafts occurred through a regenerative healing process rather than by scar formation. With further studies, this material may prove to be a useful treatment option in patients with ureteral injuries.

Use of a prostate model to assist in training for digital rectal examination.

OBJECTIVES: To assess the accuracy of prostate size estimation on digital rectal examination (DRE) before and after training with a three-dimensional prostate model relative to prostate volume by transrectal ultrasound (TRUS). METHODS: A total of 100 subjects underwent DRE by one of four family physicians (FP1, n = 34; FP2, n = 26; FP3, n = 22; and FP4, n = 18). One half were examined before any training on DRE prostate size examination and one half after the physicians were trained. Training involved teaching with a three-dimensional prostate model having posterior surface areas corresponding to the average dimensions of six different prostate volumes. The FPs were instructed to estimate the prostate size on the DRE to the nearest 5 g. A single urologist unaware of the DRE results performed TRUS on all patients to measure the prostate volume. RESULTS: Before training, the DRE size estimates ranged from 10 to 100 g (mean +/- SD 32.8 +/- 21.6), with a TRUS volume of 11 to 122 g (mean +/- SD 38.9 +/- 23.1). The correlation between the DRE and TRUS estimates was 0.25, suggesting low agreement (intraclass correlation coefficient [ICC] 0.35, 95% confidence interval 0.31, 0. 38). After training, 50 different patients had DRE size estimates of 10 to 100 g (mean +/- SD 39.4 +/- 19.7) and TRUS volume of 10 to 119 g (mean +/- SD 41.5 +/- 24.1). The correlation between the techniques was higher in patients examined after training (r = 0. 765), suggesting much better agreement between the techniques (ICC 0. 87; 95% confidence interval 0.86, 0.88). Among the physicians, agreement between DRE and TRUS was higher after training (ICC 0.64 to 0.96) than before training (ICC 0.02 to 0.49). CONCLUSIONS: Although the subjects examined before and after training differed, the agreement between TRUS and DRE prostate size estimates by the FPs appeared to be stronger after training with a three-dimensional prostate model. This model may be a useful tool to assist in training FPs and medical students to measure prostate size on DRE.