Ultraslow full‐power shock wave lithotripsy versus slow power‐ramping shock wave lithotripsy in stones with high attenuation value: A randomized comparative study

Abstract

Objectives To compare the efficacy and safety of ultraslow full‐power versus slow rate, power‐ramping shock wave lithotripsy in the management of stones with a high attenuation value. Methods This was a randomized comparative study enrolling patients with single high attenuation value (≥1000 Hounsfield unit) stones (≤3 cm) between September 2015 and May 2018. Patients with skin‐to‐stone distance >11 cm or body mass index >30 kg/m2 were excluded. Electrohydraulic shock wave lithotripsy was carried out at rate of 30 shock waves/min for group A versus 60 shock waves/min for group B. In group A, power ramping was from 6 to 18 kV for 100 shock waves, then a safety pause for 2 min, followed by ramping 18–22 kV for 100 shock waves, then a safety pause for 2 min. This full power (22 kV) was maintained until the end of the session. In group B, power ramping was carried out with an increase of 4 kV each 500 shock waves, then maintained on 22 kV in the last 1000–1500 shock waves. Follow up was carried out up to 3 months after the last session. Perioperative data were compared, including the stone free rate (as a primary outcome) and complications (secondary outcome). Predicting factors for success were analyzed using logistic regression. Results A total of 100 patients in group A and 96 patients in group B were included. The stone‐free rate was significantly higher in group A (76% vs 38.5%; P < 0.001). Both groups were comparable in complication rates (20% vs 19.8%; P = 0.971). The stone‐free rate remained significantly higher in group A in logistic regression analysis (odds ratio 24.011, 95% confidence interval 8.29–69.54; P < 0.001). Conclusions Ultraslow full‐power shock wave lithotripsy for high attenuation value stones is associated with an improved stone‐free rate without affecting safety. Further validation studies are required using other shock wave lithotripsy machines.

Ultraslow full‐power shock wave lithotripsy protocol in the management of high attenuation value upper ureteric stones: A randomized comparative study

“…Currently, there is only one study that evaluated the ultraslow rate, was a part of a protocol named ultraslow full‐power SWL (Ultraslow‐SWL) that was used for the management of renal stones of HAV 21 . In their protocol, many factors were applied to maximize the SFR in these resistant stones including the ultraslow rate, the pretreatment dose of a low‐voltage ramping SW in addition to the use of full‐power during the whole session just after the initial pretreatment phase.…”

“…In their protocol, many factors were applied to maximize the SFR in these resistant stones including the ultraslow rate, the pretreatment dose of a low‐voltage ramping SW in addition to the use of full‐power during the whole session just after the initial pretreatment phase. To antagonize the potential harm that might occur with the use of full‐power SWL, many protective methods were followed, including initial gradual ramping together giving safety pause(s) in addition to the use of an ultraslow rate, 21 which were reported to augment renal protection 18–20,22 …”

Extremely-slow, half-number shockwave lithotripsy for asymptomatic renal stones <20 mm

“…The reduced protocol may be useful for children and individuals who are experiencing extreme pain. Increasing treatment time is the major concern when a longer shock wave interval was used [9,20]. Importantly, our reduced protocol showed a similar SF rate with the same treatment time compared to the standard protocol.…”

“…However, the research only compared rates of 60-90 and 120 shocks/ min [6]. Only one randomized control study assessed the outcomes of the delivery rate of 30 shocks/min with full power than 60 shocks/min with power-ramping [20]. The SF rate was significantly better in 30 shocks/min group (76%) than in 60 shocks/min group (49%).…”

Editorial Comment to Ultraslow full‐power shock wave lithotripsy versus slow power‐ramping shock wave lithotripsy in stones with high attenuation value: A randomized comparative study

“…Challenging this unfavorable trend for SWL, Al‐Dessoukey et al . carried out a unique clinical study that evaluated the efficacy of ultraslow full‐power SWL for the treatment of stones with a high attenuation value, including large stones up to 3 cm in size . They compared the ultraslow full‐power protocol (30 SWs/min, 6–18 kV for first 100 SWs followed by 18–22 kV for the next 100 SWs, with 2‐min safety pauses after each ramping stage, then 22 kV until the end of the session) with the slow‐rate power‐ramping protocol (60 SWs/min, starting with 6–10 kV followed by a 4 kV increase after each 500 SWs, then 22 kV for the last 1000–1500 SWs).…”