Effects of extracorporeal shock wave lithotripsy on stone forming risk factors

Early changes of oxalate and calcium urine excretion in those with calcium oxalate stone formation after extracorporeal shock wave lithotripsy

OBJECTIVES

To determine the extent of transient changes of tubular function in idiopathic calcium-oxalate (CaOx) stone-bearing patients after extracorporeal shock wave lithotripsy (ESWL), calcium and oxalate excretion were measured before and after ESWL.

METHODS

In 22 patients with renal CaOx stones, the plasma values and urine excretion of creatinine, calcium, oxalate, magnesium, and citrate were measured before and on days 1 and 2 after ESWL under conditions of a standardized diet. Overnight urine collection for an 8-hour period was used to measure the urine excretion, and the values were extrapolated to a 24-hour period. For calculation of the urine ion activity, the AP(CaOx) index EQ(s) and the CaOx risk index were used.

RESULTS

After ESWL, hyperoxaluria was noted in 10 patients compared with 2 before ESWL. Hypercalciuria was seen in 11 patients after ESWL compared with 3 before. Combined hyperoxaluria and hypercalciuria was found in 7 patients after ESWL compared with 1 before. Both the oxalate/creatinine and calcium/creatinine ratios were significantly increased after ESWL. The AP(CaOx) index EQ(s) and the CaOx risk index were significantly increased after ESWL in patients with increased post-ESWL calcium and/or oxalate excretion.

CONCLUSIONS

Increased calcium and/or oxalate excretion can be seen in patients with CaOx stones early after ESWL. This increased excretion of lithogenic substances represents an increased risk of fragment apposition after ESWL for the group with a significantly increased AP(CaOx) index EQ(s) and CaOx risk index. Therefore, prophylactic measures in patients at risk early after ESWL might be warranted to prevent possible recurrent stone formation.

Estimating the effectiveness of various methods of evacuation of kidney stones, on the basis of data obtained on percentage of "stone free" and recurrent stone formation

Using the materials of more than 200 scientific papers of recent years in this review it has been carried out analysis of the effectiveness and also discussed the merits and demerits of various methods of treatment of urinary stone diseases (USD). With this purpose, for the first time it has been carried out analysis of treatment quality of USD using more important quantitative parameters of treatment efficacy: 1--percentage of "stone free"; 2--percentage of recurrent stone formation. It has been emphasized on the higher effectiveness of treatment in combination of the method of ESWL with the methods of ascending litholysis. It was shown that in order to solve problems such as etiology and pathogenesis of the disease, elaboration of quantitative risk factors of the disease, and search for effective measures on pro- and metaphylaxis of USD, and also elaboration of various (including therapeutics) medium and methods for complete and rapid evacuation of stones, it is needed to carry out intensively fundamental and applied researches in the field of urinary stone diseases.

Limitation of shockwave-induced enhanced crystal deposition in traumatized tissue by verapamil in rabbit model

OBJECTIVE

To evaluate the possible protective effect of verapamil (a calcium channel blocking agent) against the traumatizing effects of high-energy shockwaves (HESW) and new stone formation, as indicated by crystal deposition in the renal parenchyma, an experimental study was performed in rabbits.

METHODS

A total of 65 rabbits were included. During severe hyperoxaluria induced by continuous ethylene glycol (EG) (0.75%) administration, animals in the first group (N = 15) received EG only, and animals in the second group underwent administration of 500 to 1500 shockwaves, animals in the third group (N = 15) received verapamil (0.1 mg/kg) for 3 days prior to HESW application, a control group (N = 15) received various numbers (500 to 1500) of shockwaves alone. Sham-treated animals (N = 5) constituted the last group in our study. Three months after shockwave application, tissue sections obtained from treated and untreated kidneys were evaluated histopathologically under light microscopy and transmission electron microscopy (TEM) for the presence and degree of crystal deposition in the cortical parenchymal region subjected to HESW.

RESULTS

Whereas crystal deposition was evident in the intercellular region and intratubular parts of the parenchyma in animals receiving EG and HESW, especially in those receiving relatively higher numbers of shockwaves), animals receiving verapamil demonstrated limited or no crystal formation. No significant crystal deposition could be noted in specimens from animals undergoing either EG or SWL alone, and sham-treated animals demonstrated no significant alteration, as expected.

CONCLUSION

Using this model, the traumatic effects of HESW could be evaluated as a factor in new stone formation after SWL. Verapamil has been found to be protective against crystal deposition.