Ozgor F et al, 2016: External Validation and Evaluation of Reliability and Validity of The Triple D Score To Predict Stone-Free Status After Shock Wave Lithotripsy.
Ozgor F, Tosun M, Kayali Y, Savun M, Binbay M, Tepeler A.
Department of Urology, Haseki Teaching and Research Hospital , Istanbul, Turkey.
Department of Urology, Faculty of Medicine, Bezmialem Vakif University , Istanbul, Turkey.
Deparment of Urology, SJ Austria Hospital , Istanbul, Turkey.
Abstract
OBJECTIVE: The Triple D scoring system is defined as novel and simple nomogram using the main parameters (skin-to-stone distance, stone density, and volume) in order to indicate most appropriate patients for shock-wave lithotripsy (SWL). We aimed to evaluate the accuracy of the Triple D scoring system in predicting SWL success rates.
PATIENTS AND METHODS: In two tertiary academic centers, charts were retrospectively analyzed of patients who had, between January 2014 and May 2016, been treated by SWL for radiopaque kidney stones. A total of 200 patients were enrolled into the study. Parameters were calculated for each of the three specified variables. Since one point was assigned for any parameter that was less than the cutoff value, Triple D scores ranged from 0 (worst) to 3 (best).
RESULTS: Stone-free status was achieved in 115 patients (57.5%), and 85 patients had one or more residual fragments (42.5%). Differences in stone characteristics, including stone location, density, and volume, were statistically significant in patients whether SWL achieved stone-free status or not (p <0.001, p <0.001, and p <0.001, respectively). Triple D scores were significantly higher in patients treated successfully with SWL compared to patients in which SWL failed (p <0.001). Triple D scores of 0, 1, 2, and 3 correlated with stone-free rates of 41.7%, 33.7%, 69.4%, and 97%, respectively. The multivariate analyses revealed that Triple D score and stone location were identified as independent factors affecting SWL success (p <0.001 and p: 0.008, respectively). The mean number of SWL sessions was significantly higher in patients with SWL failure (p: 0.003).
CONCLUSION: Our study externally validates that the Triple D scoring system is associated with SWL success in the treatment of renal and ureteral stones. Further studies are warranted to assess clinical usefulness and the accuracy of this nomogram in different patient groups.
J Endourol. 2016 Nov 27. [Epub ahead of print]
Comments 1
There are probably few surgical fields for which so many nomograms and scoring systems have been developed as for SWL. The great advantage with the system described in this article is that the stone burden was described as a volume (mm3; l). Otherwise it is well recognized that in addition to the stone volume, skin-to-stone distance and stone composition (density) are important determinants for the outcome of SWL.
It is of course not too complicated to keep three variables in mind and the need of a mathematical summary might probably be more important when the treatment result should be analysed than before the treatment. Inasmuch as the influence of the variables discussed is well known there is certainly no need for further validation of the system. More interesting had it been to have a separate analysis of ureteral stones for which the stone-free rate was 78%.