[A modified rat model for infection-induced stone formation].

OBJECTIVE: To employ a newly modified rat model for infection-induced bladder stone formation. METHODS: 24 adult male Sprague Dawley rats were divided into 3 groups, model group (n=12), sham operation group (n=8) and control group (n=4). The surgical procedures were performed aseptically under anesthesia (25% Ultane 1.0 g/kg). The bladder in model group was exposed through a short lower midline abdominal incision, the puncture needle (G18) with guideline was inserted aseptically into bladder, a metal wire, which have been contaminated by the Proteus mirabilis, was put into the puncture canal, then implanted into the bladder lumen through the guideline. In the sham operated group the puncture needle (G18) with guideline was inserted into bladder without metal wire implanted into the bladder. There was no any operation in control group. The rats were sacrificed by excessive anesthesia at 21 days post challenge. The bladder were removed aseptically and inspected for evidence of urolithiasis. RESULTS: On Day 2 after surgery, two rats died in model group, no rats died in other groups. Twenty-one days after surgery, all of rats in model group developed various-sized bladder stones. There was no stone formation in sham operation group and control group. All stones were verified by infrared spectroscopy and optical crystallography. These stone were struvite stone. CONCLUSION: This model has a less trauma, faster recovery and excellent stone formation so that it may be used for the study of infection stone.

Shock wave lithotripsy for uric acid stones.

OBJECTIVE: To report our experience of extracorporeal shock wave lithotripsy (SWL) for patients with uric acid stones. METHODS: From December 1987 to December 2003, a total of 443 patients with uric acid stones in the kidney or ureter accepted SWL using ultrasound-guided lithotripters together with alkali therapy. Among them, 168 patients with an average stone burden of 9.1 mm were treated using an EDAP LT-01 piezoelectric lithotripter. The other patients, with an average stone burden of 9.6 mm, were treated using a Dornier Compact S electromagnetic lithotripter. RESULTS: The average duration of treatment using the EDAP LT-01 device was 52.1 minutes with a pulse frequency of 1.25-2.5 shocks per second at 100% power. The average treatment parameters on the Dornier Compact S device were 3,196 shocks at 14.8 kV. For the EDAP LT-01, the 3-month stone-free rate was 86.4%, with a retreatment rate of 24.2%. For the Dornier Compact S, the 3-month stone-free rate was 90.3%, with a retreatment rate of 29.0%. Auxiliary therapy with the push-back technique was needed in 0.45% of patients with upper ureteral stones that could not be localized using ultrasound. The treatment results were best for stones smaller than 20 mm. No anaesthesia was required for any patient. CONCLUSION: SWL with ultrasound localization for uric acid stones is safe and effective. The combination of SWL with urine alkalization may further improve the stone-free rate.

[Living animal models of the medical shock wave].

This article reviews the methods, notes and evaluation of the living animal models of the medical shock wave, including directly shocked animal models, surgical implantation of stones into animal kidney models, implantation of tumor cells into animal models and animal bone models. The living animal models play an important role in studying the medical shock wave.

[Clinical investigation of the treatment of children urethral calculi with pneumatic lithotripsy under ureteroscopy].

OBJECTIVE: To evaluate the therapeutic effects of pneumatic lithotripsy on children urethral calculi. METHODS: Twenty-two cases of the male children with urethral calculi were treated with pneumatic lithotripsy under ureteroscopy. RESULTS: All the patients were treated successfully in a single procedure. The time of lithotripsy was (5.5 +/- 2.2) minutes, and no serious complication such as obvious hematuria, infection and urethral stricture occurred. CONCLUSIONS: It is suggested that pneumatic lithotripsy under ureteroscopy is an effective and simple way for the treatment of urethral calculi in children.