The scope and place of ultrasound-monitored extracorporeal shock wave lithotripsy in a multimodality setting and the effects of experiential, audit-evoked changes on the management of ureteric calculi.

OBJECTIVE: To assess the results from ultrasound-monitored extracorporeal shock wave lithotripsy (ESWL) for ureteric stones, to compare the results with other treatment modalities and to evaluate experiential audit-evoked gains. PATIENTS AND METHODS: A review of the records of 109 patients with ureteric stones who were treated during 1990 (Group I) and 69 patients treated by ESWL during the first 10 months of 1991 (Group II), was carried out. All patients with a steinstrasse or fragments secondary to ESWL were excluded from the study. RESULTS: Of the 109 patients in Group I, 63 were treated with ESWL, nine underwent ureteroscopic push-up of the stone and 11 underwent catheter push-up prior to ESWL, 28 underwent ureteroscopic extraction/fragmentation, five underwent post-ESWL ureteroscopy and 29 underwent open ureterolithotomy (nine after failed ureteroscopy). Ureteroscopy was successful in fragmentation/extraction of 19 of 28 (68%) stones and 95% of patients were stone-free at 3 months. All patients who underwent ureterolithotomy and 84% who underwent ESWL (and post-ESWL ancillary procedures) were stone-free at 3 months. All patients who underwent ureterolithotomy, 51% of those who underwent ureteroscopy and 56% of patients who underwent ESWL needed only one treatment. The mean stone burdens of patients in Groups I and II were comparable but more patients presented with larger stones (> 15 mm length, > 100 mm2 surface area) in Group II. The stone-free rates for ESWL monotherapy with ESWL increased from 84% in 1990 to 92% in 1991. A higher proportion of stones were treated in situ in 1991 and a stent was used less frequently in obstructed ureters. Post-ESWL procedures fell from 8% in 1990 to 6% in 1991 and the proportion of patients who required more than one treatment fell from 44% in 1990 to 14% in 1991. CONCLUSIONS: The choice of treatment for patients with ureteric stones is critical but will vary depending on the individual's circumstances, the availability of equipment, costs and time required to perform the procedure. The results obtained using ESWL for ureteric stones improved considerably over the course of the study as a result of experience and refinement of the technique. Stones located in more difficult systems such as in kidneys with a thin cortex and those located above the ischial spine were no longer subjected to ESWL. Audit of the results obtained following treatment allows identification of problem areas, alerts physicians to alternative methods of treatment and gives an objective quantification of experience, assisting rational decision making with consequent improved success.

Extracorporeal shock wave lithotripsy for bladder stones.

Between December 1989 and July 1991, 29 patients with bladder stones were treated on the MPL 9000 extracorporeal shock wave lithotriptor using ultrasound for localisation. The mean stone dimensions were 22.65 x 15.17 mm (< 400 mm2 in 20 patients); 75% of patients required only 1 ESWL session but the largest stone (2025 mm2) required 3. Whilst larger stones tended to require more shock waves, linear regression analysis showed a poor fit and factors other than size (operator experience and stone hardness) may determine the number of shock waves required. Satisfactory fragmentation was obtained in all patients. All were treated under intravenous analgesia without anaesthesia. Three patients also had outflow obstruction and were treated by transurethral resection of the prostate (TURP) on the day after completing ESWL. ESWL prior to TURP reduces the morbidity and operating time associated with endoscopic therapy of bladder stones. Macroscopic fragments remaining after ESWL can be washed out at TURP.