Ichiyanagi O. et al., 2019: Reinforcement of the Triple D score with simple addition of the intrarenal location for the prediction of the stone-free rate after shockwave lithotripsy for renal stones 10-20 mm in diameter
Ichiyanagi O, Fukuhara H, Kurokawa M, Izumi T, Suzuki H, Naito S, Nishida H, Kato T, Tsuchiya N.
Department of Urology, Yamagata University Faculty of Medicine, 2-2-2 Iida-nishi, Yamagata, 998-9585, Japan. Department of Urology, Yamagata Prefectural Kahoku Hospital, 111 Aza-Gassando, Yachi, Kahoku, 999-3511, Department of Urology, Yamagata University Faculty of Medicine, 2-2-2 Iida-nishi, Yamagata, 998-9585, Japan.
Department of Urology, Nihonkai General Hospital, 30 Akiho-cho, Sakata, 998-8501, Japan.
Department of Urology, South Miyagi Medical Center, 38-1 Aza-nishi, Ogawara, Miyagi, 989-1253, Japan.
Department of Urology, Yamagata City Hospital Saiseikan, 1-3-26 Nanoka-mahi, Yamagata, 990-8533, Japan.
We investigated the clinical efficacy of the Triple D score (TrD-S) on stone-free rate (SFR) prediction following shockwave lithotripsy (SWL) for renal stones 10-20 mm in diameter and modified the scoring system to improve outcome prediction. METHODS: We retrospectively examined clinical data from the medical records of 226 consecutive patients who underwent SWL for 10-20 mm kidney stones. The TrD-S was calculated according to the cutoffs of < 150 mm3 for stone volume, < 600 Hounsfield unit for stone density, and < 12 cm for skin-to-stone distance on computed tomography. The Quadruple D score was defined as the sum of the TrD-S and stone location (0/1 point for intrarenal stone distribution at lower/non-lower poles, respectively). Complete clearance 3 months after the final SWL was considered the stone-free status. RESULTS: The residual group (n = 102) had significantly older age, larger stones, higher stone density, higher lower-pole stone incidence, and lower TrD-S than the stone-free group (n = 124). In the multivariate analysis, age, TrD-S, and non-lower-pole stones independently predicted the SFR. The TrD-Ss of 0, 1, 2, and 3 points showed SFRs of 40.0%, 51.9%, 73.0%, and 100.0%, respectively. The Quadruple D scores of 0, 1, 2, 3, and 4 points showed SFRs of 0.0%, 37.9%, 54.5%, 84.4%, and 100.0%, respectively, with better prediction accuracy than the TrD-S (p = 0.01). CONCLUSIONS: The TrD-S is successfully validated for use in Japanese patients with 10-20-mm renal stones. Simple addition of the stone location to the TrD-S could reinforce SFR prediction after SWL.
Int Urol Nephrol. 2019 Feb;51(2):239-245. doi: 10.1007/s11255-018-02066-1. Epub 2019 Jan 2.
The Triple D score - composed of SSD, stone density, and stone volume - was introduced in 2015 (1) and was revalidated and confirmed by others, who pointed out the additive predictive power of stone location (2 ).
Interestingly in the present paper on Japanese patients the SSD which is related to the BMI had no significant effect on the ESWL outcome. The authors’ explanation is that obesity in Japanese people is rare with 2–3% of the Japanese population, in contrast to the 10–20% in Europe and the USA.
In only 50 % was a stone analysis available in both groups and the failure rate showed no correlation to the stone analysis. However, Calcium oxalate was not differentiated into Calciumoxalate-monohydrate which is more resistant to ESWL and Calciumoxalate-dihydrate which is more amenable to ESWL.
Otherwise this is a good contribution to an easy and better patient selection for ESWL.
1 Tran TY, McGillen K, Cone EB, Pareek G (2015) Triple D Score is a reportable predictor of shockwave lithotripsy stone-free rates. J Endourol 29(2):226–230
2 Ozgor F, Tosun M, Kayali Y, Savun M, Binbay M, Tepeler A (2017) External validation and evaluation of reliability and validity pf the Triple D Score to predict stone-free status after extracorporeal shockwave lithotripsy. J Endourol 31(2):169–173