Bovelander E. et al., 2019: The Influence of Pain on the Outcome of Extracorporeal Shockwave Lithotripsy
Bovelander E, Weltings S, Rad M, van Kampen P, Pelger RCM, Roshani H.
Department of Urology, Leiden University Medical Center, Leiden, The Netherlands.
Anesthesiology, Leiden University Medical Center, Leiden, The Netherlands.
Medical Statistics, Haga ziekenhuis, 's-Gravenhage, Leiden University Medical Center, Leiden, The Netherlands.
Introduction: The aim of this study was to determine the predictive value of pain scores on the efficacy of extracor-poreal shockwave lithotripsy (ESWL) and to identify other predictive risk factors for treatment success. Materials and Methods: A total of 476 patients who underwent ESWL (piezoelectric lithotripsy) for urolithiasis between September 2011 and December 2015 were identified. The primary end-point of this study was success rate, which was evaluated 4 months after ESWL. The secondary outcome was the occurrence of complications as a result of ESWL. Results: The average pain perception was reported at 5 on a scale from 0 to 10. The overall success rate of ESWL was found to be 43.9% and the success rate after the first ESWL was 35.1%. Univari-ate analysis showed no significant correlation between pain score and success of ESWL (p = 0.135). The level of intensity was correlated with pain scores (Pearson correlation -0.423, p < 0.001). Univariate analysis identified five predictive factors: sex, stone location, stone size, hydronephrosis and the use of tamsulosin. Multivariate logistic regression analysis showed that sex, stone location and size independently in-fluenced the success of ESWL (p = 0.045, p = 0.001 and p < 0.001). Conclusion: No correlation was found between the pain scores and efficacy of ESWL. Despite this absence, pain scores during ESWL sessions remain high and additional analgesia would improve patient satisfaction.
Curr Urol. 2019 Mar 8;12(2):81-87. doi: 10.1159/000489424. FREE ARTICLE
It is my personal experience that adequate pain control is a pre-requisite for successful SWL. This is at least the case for patients treated with electrohydraulic (EH) and electromagnetic (EM) shockwave generation.
The current article is based on experience with piezoelectric lithotripsy (EPL; Piezolith 3000) in which the pain experience is considered lower than with the other two methods. Despite this pain treatment is necessary and the authors solved that problem by administration of 1000 mg of paracetamol and 100 mg of diclofenac 30 minutes before the treatment. I do not know if this should be considered as adequate treatment, but it is obvious that the experience of pain varied considerably from no pain (score 0) to severe pain (score 7-8); the latter level was reported in almost one third of the patients.
It is not exactly clear what the authors expected from their study, but they identified two possible effects of pain: inaccurate focusing with low hit-rate and/or inability to treat the patient with sufficiently powerful shockwaves.
There is no direct information either on the first or the second effect, but it is stated that with higher pain scores the shockwave power (intensity) was lower. It thus seems likely that it was the patients´ pain experience that dictated which power level that was applied.
I was looking for data on SFR relative to shockwave intensity and/or pain score, but such data are not easily found. There is, however, most certainly a pronounced variation in all three variables (SFR, power, pain). Moreover, patients with high pain score might have been given opioids to reduce pain while there pain score probably remained unchanged in the protocol.
The high pain scores that were recorded with EPL indicates that the analgesic regimen was insufficient and that it certainly had been possible to treat the patients in a more effective way with other analgesics. My personal experience with EM lithotripsy has convinced me that intermittent administration of small doses of alfentanyl and propofol is a winning concept. Our patients also were given a suppository of 50 mg of diclofenac 30 minutes before the treatment.