Evolution of shockwave lithotripsy (SWL) technique: a 25-year single centre experience of >5000 patients

To assess the impact of various treatment optimisation strategies in shockwave lithotripsy (SWL) used at a single centre over the last 25 years.

In all, 5017 patients treated between 1989 and 2013 were reviewed and divided into groups A, B, C and D for the treatment periods of 1989-1994 (1561 patients), 1995-2000 (1741), 2001-2006 (1039) and 2007-2013 (676), respectively. The Sonolith 3000 (A and B) and Dornier compact delta lithotripters (C and D) were used. Refinements included frequent re-localisation, limiting maximum shocks and booster therapy in group B and Hounsfield unit estimation, power ramping and improved coupling in group D. Parameters reviewed were annual SWL utilisation, stone and treatment data, retreatment, auxiliary procedures, complications and stone-free rate (SFR).

The SFR with Dornier compact delta was significantly higher than that of the Sonolith 3000 (P < 0.001). The SFR improved significantly from 77.58%, 81.28%, 82.58% to 88.02% in groups A, B, C, and D, respectively (P < 0.001). There was a concomitant decrease in repeat SWL (re-treatment rate: A, 48.7%; B, 33.4%; C, 15.8%; and D, 10.1%; P < 0.001) and complication rates (A, 8%; B, 6.4%; C, 4.9%; and D, 1.6%; P < 0.001). This led to a rise in the efficiency quotient (EQ) in groups A-D from 50.41, 58.94, 68.78 to 77.06 (P < 0.001).The auxiliary procedure rates were similar in all groups (P = 0.62).

In conclusion, improvement in the EQ together with a concomitant decrease in complication rate can be achieved with optimum patient selection and use of various treatment optimising strategies.