Extracorporeal shock wave lithotripsy (ESWL) for urinary tract stones using Dornier MFL 5000, performed by the technician

Impact of Case Volume on Shock Wave Lithotripsy Outcomes: Data from the National Shock Wave Lithotripsy Database of New Zealand

Purpose: To assess the impact of individual operator case volume on shock wave lithotripsy (SWL) treatment outcomes in more than 9000 stone cases over a 20-year period in New Zealand. Materials and Methods: Stone cases treated with SWL on the Mobile Medical Technology (MMT) vehicle between June 19, 1995, and December 1, 2014, were identified. Data collection was undertaken prospectively for patient, stone, and treatment characteristics, and retrospectively for treatment outcomes. Multivariate analysis using binary logistic regression was undertaken to assess whether radiographer stone case volume (stones/year) was an independent predictor of SWL success (stone free or clinically insignificant residual fragments ≤4 mm at follow-up). Results: Sixteen radiographers delivered treatment to the included cohort (9039 stone cases), with a median case volume (stones/year) of 73 (range: 37-197) and median total of 425 stones treated (range: 71-1721). The two radiographers with highest case volumes achieved the highest success rates. Radiographer case volume (stones/year) was independently associated with SWL success (odds ratio [OR]: 1.004, 95% confidence interval [CI]: 1.003-1.005, p < 0.0001) and reduced need for post-SWL hospital admission (OR: 0.997, 95% CI: 0.994-1.000, p = 0.028), but there was no associated decrease in post-SWL urosepsis (OR: 0.999, 95% CI: 0.974-1.025, p = 0.941), perinephric hematoma (OR: 1.003, 95% CI: 0.985-1.020, p = 0.778), or need for auxiliary procedures (OR: 1.000, 95% CI: 0.998-1.002, p = 0.871). Conclusions: SWL success rates can be improved by increasing the frequency of cases performed by individual operators. In this multicenter cohort of more than 9000 stone cases treated over a 20-year period, the best outcomes were seen for those radiographers performing >150 cases per year.

Impact of radiological technologists on the outcome of shock wave lithotripsy

OBJECTIVE

To evaluate the correlation of radiological technologists (RTs) and the outcome of shock wave lithotripsy (SWL) in terms of fluoroscopy time, fragmentation rate, and stone-free rate.

MATERIAL AND METHODS

A retrospective review of a prospectively collected database of 601 SWL treatments between June 2009 and March 2010 was performed. Patients with radiolucent stones were excluded. SWL was done by 6 RTs with different levels of experience. Follow up was available for 534 treatments. Multivariate analysis was performed.

RESULTS

RTs (A-F) performed 144, 109, 118, 58, 57, and 48 SWL sessions, respectively. There was no statistical difference among RTs in terms of mean stone size or stone location. Compared with other RTs, RT A had a significantly lower mean fluoroscopy time of 129 seconds (95% CI 120.8-137.3) (P <.001), higher stone-free rate (75.7%; P = .035), and stone fragmentation rate after a single SWL session (82.6%; P = .004). After correcting for stone size and location, fluoroscopy time (P <.001), fragmentation rate (P = .002), and stone-free rate (P = .04) maintained their significance. When comparing the top 3 RTs performing >100 SWL sessions, RTs B and C had significantly higher fluoroscopy time compared with RT A (OR [95% CI] 1.84 [1.38-2.45]; P <.001 and 2.67 [2.00-3.57]; P <.001), respectively. After correcting for stone size and location, RT B had significantly lower fragmentation rate when compared with RT A (OR [95% CI] 0.21 [0.05-0.86], P = .03]. However, there were no significant differences among the top 3 RTs in terms of stone-free rates.

CONCLUSION

RTs significantly differ in fluoroscopy usage in addition to stone fragmentation and stone-free rates.