Geraghty R et al, 2015: Shock wave lithotripsy outcomes for lower pole and non-lower pole stones from a university teaching hospital: Parallel group comparison during the same time period.
Geraghty R, Burr J, Simmonds N, Somani BK.
Department of Urology, University Hospital of Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK.
INTRODUCTION: Shock wave lithotripsy (SWL) is a treatment option for all locations of renal and ureteric stones. We compared the results of SWL for lower pole renal stones with all other non-lower pole renal and ureteric stones during the same time period.
MATERIAL AND METHODS: All SWL procedures were carried out as day case procedures by a mobile lithotripter from January 2012 to August 2013. The follow-up imaging was a combination of KUB X-ray or USS. Following SWL treatment, the stone free rate (SFR) was defined as ≤3 mm fragments.
RESULTS: A total of 148 patients with a mean age of 62 years underwent 201 procedures. Of the 201 procedures, 93 (46%) were for lower pole stones. The non-lower pole stones included upper pole (n = 36), mid pole (n = 40), renal pelvis (n = 10), PUJ (n = 8), mid ureter (n = 3), upper ureter (n = 5) and a combination of upper, middle and/or lower pole (n = 6). The mean stone size for lower pole stones (7.4 mm; range: 4-16 mm) was slightly smaller than non-lower pole stones (8 mm; range: 4-17 mm). The stone fragmentation was successful in 124 (62%) of patients. However, the SFR was statistically significantly better (P = 0.023) for non-lower pole stones 43 (40%) compared to
lower pole stones 23 (25%). There were 9 (4%) minor complications and this was not significantly different in the two groups.
CONCLUSIONS: Although SWL achieves a moderately high stone fragmentation rate with a low complication rate, the SFR is variable depending on the location of stone and the definition of SFR, with lower pole stones fairing significantly worse than stones in all other locations.
Urol Ann. 2015 Jan-Mar;7(1):46-8. doi: 10.4103/0974-7796.148601. FREE ARTICLE
This comparative study between patients treated for stones in the lower calyx (LP) and those treated for stones in other positions (NLP) not unexpectedly showed a higher stone-free rate in patients treated for NLP-stones. This result should, however, be considered in view of the fact that also ureteral stones were included in the NLP group. Following disintegration of stones in the ureter all such patients will likely be stone-free.
It is of interest to note that in both groups the disintegration of LP and NLP stones were 61% and 63%, respectively. Despite an almost identical stone disintegration the stone-free rate differed. Anatomical geometry and calyx physiology most certainly have played important roles for fragment clearance, but this result also suggests that some kind of inversion therapy might be beneficial as an auxiliary step after (or during?) SWL.