Can infundibular height predict the clearance of lower pole calyceal stone after extracorporeal shockwave lithotripsy?

Revisiting the morphology of pelvicalyceal system in human cadaveric kidneys with a systematic review of literature

Objective

Renal collecting system macroscopically consists of minor calyx, major calyx, renal pelvis and ureter. Stone in renal collecting system is a common presentation in everyday urological practice. The prevalence of renal calculi ranges from 4% to 20% in different geographical distribution. Anatomical variation in renal collecting system plays a significant role in formation of calculi in its parts. The large extra renal pelvis leads to stagnation of urine for longer durations and formation of stones. The stone free rate after percutaneous nephrolithotomy and extra corporeal shock wave lithotomy is significantly related to anatomical factors, particularly the type of renal pelvis and dimensions (length and width) of lower infundibulum. Previous authors described the morphology of pelvicalyceal system in a highly variable manner and the available anatomical description of pelvicalyceal system is contradictory and incomplete. Hence an attempt has been made to provide the precise anatomy of pelvicalyceal system in adult human kidneys.

Methods

We studied 196 formalin embalmed kidneys to note the number of infundibulum, major and minor calyces. The location and shape of pelvis were also studied.

Results

The intra-renal pelvis was narrow and had funnel shaped appearance in 95 of total 196 (48.5%) specimens, and the extra-renal pelvis was dilated as balloon shaped in 43 of 196 (21.9%) specimens. In 41 (20.9%) specimens, the renal pelvis was having partially intra- and extra-renal in location. Bilateral symmetry was found in only 27.1% of 196 renal collecting systems. The length of lower infundibulum was more than 22 mm in 19 (9.7%) of 196 cases which directly affects the stone clearance rate during open and endoscopic surgeries on pelvicalyceal system.

Conclusion

This study provides the accurate morphological details of the shape and dimensions of renal pelvicalyceal system to help the urologists and nephrologists.

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

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.