Purpose: To achieve an almost 100% stone-free rate by means of further developing and standardizing the procedure.
Patients and methods: 100 consecutive patients with single or multiple renal calculi were prospectively enrolled in the study. Flexible ureterorenoscopy was performed as a completely standardized operation by the same two experienced surgeons. Primary outcome was an "endoscopic" (immediate) stone-free status as determined by endoscopic inspection at the end of surgery. In cases of residual fragments, a reevaluation by CT was performed after 3 months.
Results: The endoscopic stone-free rate was 97%. In three patients with a cumulative stone size >20 mm, a completely stone-free status could not be achieved in the primary procedure. In these patients, a CT scan after 3 months showed complete clearance from all residual fragments in two; this translates into a primary (after one procedure) stone-free rate after 3 months of 99%. Medium cumulative stone size was 9.8 mm (4-40 mm); in 44 patients, multiple calculi were extracted. Forty-nine patients received a ureteral stent at the end of the operation; two patients had to have stent placement for new onset hydronephrosis and/or colicky pain or fever. Overall complication rate was 7%. Results are limited, because no routine CT scan was used to evaluate stone clearance.
Conclusion: By means of a standardized surgical approach and use of technical equipment of the newest generation, it is possible to achieve very high stone-free rates without compromising safety. This approach, however, necessitates use of considerable resources, both technical/surgical and financial.