Is newer always better? A comparative study of 3 lithotrlptor generations

Purpose: At a single center we compared the efficacy of 3 generations of lithotriptors using identical protocol inclusion and followup criteria but with different modes of anesthesia. Materials and Methods: We compared stone disintegration and dilatation of the pyelocaliceal system achieved in a prospective, randomized trial comparing the original HM3 (Dornier Medtech, Kennesaw, Georgia) and Lithostar (R) Plus (LSP) lithotriptors, and a matched, consecutive series of 107 treatments with the Modulith (R) SLX. Stone disintegration and dilatation of the pyelocaliceal system were evaluated by abdominal plain x-ray and renal ultrasonography I day and 3 months after treatment. Results: A total of 82 treatments with the HM3, 75 with the LSP and 107 with the SLX were analyzed, matched for stone burden and location within the pyelocaliceal system. On postoperative day 1, 91%, 65% and 48% patients treated with the HM3, LSP and SLX, respectively, were stone-free or had fragments that were 2 mm or less (HM3 vs LSP p < 0.001, HM3 vs SLX p < 0.001 and LSP vs SLX p = 0.015). Three to 5 mm fragments were found in 7%, 21% and 35% of patients (p = 0.006, < 0.001 and 0.06), and fragments 6 mm or greater were found in 1%, 14% and 15% (p = 0.002, < 0.001 and 0.1, respectively). The re-treatment rate was 4% in the HM3 group, 13% in the LSP group and 38% in the SLX group (HM3 vs LSP p = 0.05, HM3 vs SLX p < 0.001 and LSP vs SLX p < 0.001). Obstructive pyelonephritis occurred in 1% of the HM3 group, 8% of the LSP group and 5% of the SLX group (HM3 vs LSP p = 0.02, HM3 vs SLX p = 0.12 and LSP vs SLX p = 0.4). All re-treatments except those in 5 patients were performed with the HM3. Therefore, the 3-month stone-free rate was comparable in all 3 groups (HM3 87%, LSP 80% and SLX 81%). Conclusions: This study indicates that the HM3 lithotriptor disintegrates caliceal and renal pelvic stones better than the LSP and SLX machines, resulting in fewer complications and re-treatments. Disintegration with the LSP machine was also superior to that of the SLX with a need for fewer re-treatments.