Yucel MO et al, 2017: The Respiratory Induced Kidney Motion: Does It Really Effect the Shock Wave Lithotripsy?
Yucel MO, Ozcan S, Tirpan G, Bagcioglu M, Aydin A, Demirbas A, Karakan T.
Department of Urology, Adiyaman University, Adiyaman, Turkey.
Department of Urology, Izmir Katip Çelebi University, Izmir, Turkey.
Department of Urology, Ankara Training and Research Hospital, Ankara, Turkey.
PURPOSE: To investigate the effect of respiratory induced kidney mobility on success of shock wave lithotripsy (SWL) with an electrohydraulic lithotripter.
MATERIALS AND METHODS: Between May 2013 and April 2015, 158 patients underwent SWL treatment for kidney stones with an electrohydraulic lithotripter. The exclusion criteria were presence of a known metabolic disease (such as cystinuria), non-opaque stones, need for focusing with ultrasonography, abnormal habitus, urinary tract abnormalities, and inability to tolerate SWL until the end of the procedure. Stones greater than 20 mm, and lower pole stones were also excluded. The movement of the kidneys were measured with fluoroscopy guidance.
RESULTS: The procedure was successful in 66.7% of the males, and 56.9% of the females. The mean stone size was 11 ± 3 mm in the successful group, and it was 14 ± 4 mm in the unsuccessful group. The mean stone mobility rate was 32 ± 10 in the successful group and 40 ± 11 in the unsuccessful group. Multivariate analysis showed that stone size and kidney mobility affected the success rate significantly, however Hounsfield Unit (HU) did not.
CONCLUSION: The current study shows the significant effect of kidney motion on the success of SWL. Further studies with different lithotripters are needed to determine the significance of kidney mobility.
Urol J. 2017 Jan 23;15(1):11-15. doi: 10.22037/uj.v0i0.3774.
This paper deals with a well-known fact. I admit that I did not understand how the authors measured the kidney motion: “The size of the stone was calculated taking the longest axis of the stone on KUB into consideration. The ratio of the size of the stone measured on KUB and the size of the stone measured on fluoroscopy was calculated. The centre of the stone and the centre of the fluoroscopy were marked when the patient was monitored with fluoroscopy. Then, cranial and caudal motion of the stone was marked on fluoroscopy, and the motion of the kidney on fluoroscopy was calculated by comparing it with the stone size.” based on a formula:”A: Craniocaudal size of the stone on kidney-ureter-bladder X-ray, B: The size of the stone under fluoroscopy, C: The mobility of the stone with respiration. M=AxC/B (Calculation of actual mobility by calculating the ratio of the actual size of the stone on kidney-ureter-bladder X-ray and its size on fluoroscopy).”
Figure A illustrating the measurement suggests to me that the stone size on the KUB was measured 30 % to big. Single measurements are not reported.