Reduction of high-energy shock-wave-induced renal tubular injury by selenium

In shock-wave-induced renal injury cavitation-generated free radicals play an important role. Using an in vitro model with Madin-Darby canine kidney (MDCK) cells, we investigated the influence of selenium, a free radical scavenger, in shock-wave-induced tubular cell injury. Suspensions of MDCK cells (33 × 10⁶ cells/ml) were placed in small containers (volume 1.1 ml) for shock wave exposure. Two groups of 12 containers each were examined: (1) control (no medication), (2) selenium (0.4 μg/ml nutrient medium). Six containers in each group were exposed to shock waves (impulse rate 256, frequency 60 Hz, generator voltage 18 kV), while the other six containers in each group served as a control. After shock wave exposure, the concentration of cellular enzymes such as lactate dehydrogenase (LDH), N-acetyl-β-glucosaminidase (NAG), glutamate oxaloacetate transaminase (GOT) and glutamate lactate dehydrogenase (GLDH) in the nutrient medium was examined. Following shock wave exposure there was a significant rise in LDH, NAG, GOT and GLDH concentrations. Selenium reduced this enzyme leakage significantly. Thus we conclude that selenium protects renal tubular cells against shock-wave-induced injury. Since selenium is an essential part of glutathione peroxidase, this effect seems to be mediated by a reduction in reactive oxygen species. Received: 23 September 1998 / Accepted: 10 March 1999     

Hyperoxaluria-induced oxidative stress and antioxidants for renal protection

Renal cellular exposure to oxalate (Ox) and/or CaOx crystals leads to the production of reactive oxygen species (ROS), development of oxidative stress followed by injury and inflammation. Renal injury and inflammation appear to play a significant role in stone formation. ROS are produced from many sources and involve a variety of signaling pathways. Tissue culture and animal model studies show that treatments with anti-oxidants and free radical scavengers reduce Ox/CaOx crystal induced injuries. In addition, CaOx crystal deposition in kidneys is significantly reduced by treatments with antioxidants and free radical scavengers, indicating their efficacy. These results point towards a great potential for the therapeutic application of antioxidants and free radical scavengers to reduce stone recurrence particularly after shock wave lithotripsy, which is itself known to generate ROS and cause renal damage.     

Damaging effects of high energy shock waves on cultured Madin Darby Canine Kidney (MDCK) cells

Summary Shock wave lithotripsy (ESWL) has become an almost non-invasive standard treatment modality for urolithiasis. Several investigations, however, demonstrated that ESWL is not completely free of side effects. Among others alteration of renal tubular function has been reported. To study the effect of shock waves on tubular cells directly an in-vitro model with cultured Madin Darby Canine Kidney (MDCK) cells was established. Suspensions of MDCK cells (7 groups of 6 containers each) were exposed to 0, 16, 32, 64, 128, 256 shock waves (Dornier HM4, 18 kV). Before and 0, 1, 3, 6, 9, 12, 24 h after ESWL the following parameters were measured in the nutrient medium: lactate dehydroxygenase (LDH), glutamate oxalacetate transaminase (GOT), electrolytes. LDH and GOT increased depending on the number of shock waves indicating a membrane damage of MDCK cells. The MDCK model seems suitable for further studies on the effect of shock waves on renal tubular cells.     

In vivo assessment of free radical activity during shock wave lithotripsy using a microdialysis system: the renoprotective action of allopurinol.

PURPOSE: Shock wave lithotripsy is believed to cause renal damage directly through cellular injury from high energy shock waves and indirectly through vascular injury and resultant ischemia, which gives rise to oxygen free radical compounds. The transient and volatile nature of free radicals and derived products makes their detection difficult. Moreover, certain medications may provide a protective effect against shock wave lithotripsy induced renal parenchymal injury. We introduced an innovative microdialysis system for in vivo sampling of interstitial fluids that can be analyzed for free radical mediated lipid peroxidation products after shock wave lithotripsy treatment in the swine model. In addition, this system was used to test the antioxidant or renoprotective action of allopurinol. MATERIALS AND METHODS: Ten juvenile swine were assigned to a nonmedicated control group that underwent shock wave lithotripsy or to a group that was premedicated with allopurinol before shock wave lithotripsy. Each group of animals underwent shock wave lithotripsy to the lower pole of the right kidney and received a total of 10,000 shock waves. Dialysate fluid was collected at 1,000-shock wave increments via probes surgically implanted into the lower pole of the right and left kidneys before lithotripsy. Samples were immediately preserved in liquid nitrogen and subsequently analyzed for the presence and concentration of conjugated diene levels, a measure of lipid peroxidation. Five additional juvenile swine were assigned to a sham treated group that did not undergo shock wave lithotripsy. Dialysate fluid was collected from the lower pole of the right and left kidneys to establish baseline or pre-lithotripsy levels of conjugated dienes. RESULTS: After shock wave lithotripsy conjugated diene levels increased almost 100-fold over that in the right kidneys of the nonmedicated control group. The difference was statistically significant compared to levels in the contralateral untreated kidneys (p <0.01). Right kidneys in the group premedicated with allopurinol did not demonstrate an increase in conjugated diene levels during shock wave lithotripsy. CONCLUSIONS: The results of this study confirm shock wave lithotripsy induced free radical activity as well the antioxidant and protective nature of allopurinol. The newly described microdialysis system enables real-time sampling of interstitial fluids during shock wave lithotripsy. It represents a unique method for assessing free radical formation and evaluating the protective effects of additional antioxidant medications.     

Pyrrolidine dithiocarbamate attenuate shock wave induced MDCK cells injury via inhibiting nuclear factor-kappa B activation

Shock wave lithotripsy (SWL)-induced renal damage appears to be multifactorial. Recent data indicated that the mechanism of renal tissue damage secondary to SWL is similar to that of ischemia reperfusion injury. Nuclear factor-kappa B (NFκB) and its target genes, inducible nitric oxide synthase (iNOS) and cyclooxygense-2 (COX-2), have been demonstrated to play a very important role in a variety of cells or tissues ischemia reperfusion injuries. Thus in the present study, using an in vitro model MDCK cells, we investigated the role of NFκB and its target cytotoxic enzyme in shock wave-induced renal cellular damage. We also examined whether inhibition this pathway by pyrrolidine dithiocarbamate (PDTC) is contributed to alleviate SWL-caused cell damage. Suspensions of MDCK cells were placed in containers for shock wave exposure. Three groups of six containers each were examined: control group, no shock wave treatment and SWL group, which received 100 shocks at 18 kV; 3 SWL + PDTC group. PDTC were added to the suspensions before shock wave exposure. After shock wave 0, 2, 4, 6 and 8 h, respectively, the cell supernatants were detected for the level of MDA and release of LDH. At post-shock wave 8 h, cells were harvested to detect the nuclear translocation of NFκBp65 by immunofluorescence staining. Degradation of IκB-а (an inhibitor protein of NFκB) and expression of iNOS and COX-2 were also examined by western blotting. Our results indicated that shock wave initiated the apparent activation of NFκB, which in turn induced high expression of iNOS and COX-2. Blocking degradation of IκB-а by PDTC was contributed to decrease the expression of iNOS. And the level of MDA and the release of LDH were also significantly reduced by using PDTC. However, the degree of COX-2 expression does not differ significantly between SWL and SWL + PDTC groups. Activation of NFκB and subsequent expression of its target cytotoxic enzyme have been demonstrated to be a potential and crucial mechanism in SWL-induced renal cell damage. Blocking this pathway by PDTC is contributed to protect against cellular damage from shock wave.     

Pathologic effects of ESWL on canine renal tissue

The introduction of extracorporeal shock wave lithotripsy (ESWL) has provided an avenue for dealing with many urinary stones noninvasively. The margin of safety for the kidney during shock wave administration is largely undefined. A pilot study was performed where six kidneys in five female mongrel dogs were shocked. Group A kidneys were given 1,776, 4,500, 6,000, or 8,000 shocks, respectively, at 18-24 kV. Group B kidneys received 1,600 and 8,000 shocks (18-24 kV). The number of shocks per electrode ranged from 500 to 4,538 and averaged 2,490. The dogs were sacrificed forty-eight to seventy-two hours (Group A) or twenty-eight to thirty-two days (Group B) post-treatment. Modest damage (hematoma and/or interstitial hemorrhage) was noted in all kidneys. Evidence of permanent change (fibrosis) was noted in both Group B kidneys. Complete necrosis of the kidney was not seen after administration of 8,000 shocks. These preliminary data indicate that lithotripsy can, in some circumstances, produce renal damage in the canine model.     

Shock wave lithotripsy causes ipsilateral renal injury remote from the focal point: the role of regional vasoconstriction

PURPOSE: Shock wave lithotripsy induced renal damage can occur as a result of multiple mechanisms, including small vessel injury and free radical production. Previous studies have demonstrated that shock wave lithotripsy exerts a regional change in renal hemodynamics, resulting in a global reduction in the glomerular filtration rate and renal plasma blood flow. We determined if biochemical evidence of cellular damage could be identified in ipsilateral locations remote from the shock wave site or in the contralateral kidney, suggesting regional or systemic alterations in renal function. MATERIALS AND METHODS: Ten juvenile female swine underwent open insertion of microdialysis probes into the renal parenchyma at the right upper and lower poles, and left lower pole. The animals were divided evenly into a sham and a treatment group. Dialysate samples were collected from all 3 sites from the sham group at 10-minute intervals for 100 minutes and quantitatively assessed for conjugated dienes, a measure of lipid peroxidation and free-radical activity, signifying renal cellular damage. The animals in the treatment group underwent shock wave lithotripsy focused on the right lower pole. Dialysate samples were collected from all 3 sites at baseline and at 1,000 shock intervals for a total of 10,000 shocks and analyzed for conjugated dienes. The results from the sham and treatment groups as well as from the different locations within each group were compared using Student's t test. RESULTS: The mean conjugated diene ratio for the sham group was 3.59, 3.42 and 2.7 microM. for the right upper and lower poles, and left kidney (p >0.05). A dose related increase in conjugated diene ratio levels from the right lower pole (lithotripsy site) and to a lesser degree from the ipsilateral right upper pole were observed, which were significantly different from sham group measurements or the contralateral kidney of the treatment group (p <0.05). The elevation in conjugated diene levels at the lithotripsy site was also noted to be significantly greater than that of the upper pole of the ipsilateral kidney (p <0.05). CONCLUSIONS: The increase in free radical activity at a site remote from the treated region suggests detrimental global effects from shock wave lithotripsy therapy. These observations could be the result of vasoconstriction throughout the treated kidney with resultant ischemia-reperfusion injury. Although these global renal effects may subject patients with baseline renal dysfunction to irreversible renal damage, the clinical significance of our findings is unclear and warrants further investigation.     

Complex struvite calculi treated by primary extracorporeal shock wave lithotripsy and chemolysis with hemiacidrin irrigation

Ten patients with complex struvite stones were treated successfully with primary extracorporeal shock wave lithotripsy followed by chemolysis with 10 per cent hemiacidrin renal irrigation. The average number of treatments per renal unit was 1.2 and an average of 2,688 shocks was administered per treatment. No patient required a blood transfusion. Ureteral obstruction did not occur in those patients receiving planned hemiacidrin irrigation immediately after extracorporeal shock wave lithotripsy. At 6-week followup 9 patients were free of residual fragments. The combination of extracorporeal shock wave lithotripsy and hemiacidrin chemolysis represents a satisfactory alternative to the traditional surgical management of complex struvite calculi.     

Temporal effects of shock wave lithotripsy.

Previous studies have demonstrated that renal parenchymal injury following extracorporeal shock wave lithotripsy is dependent upon shock wave power as well as the total number of shock waves administered. In order to determine the deleterious effects of temporal versus cumulative doses of shock wave administration, adult female rabbits were divided into five groups receiving either: 1000 shock waves in one session; 2000 shock waves in one session; 2000 shock waves in two sessions, one week apart; unilateral nephrectomy without lithotripsy; or anesthesia only as control population. One month following lithotripsy, renal functional studies for gamma glutamyl transferase and N-acetyl-beta-glucosaminidase revealed persistent enzymuria in the animals treated with 2000 shocks in one session. Pathologic studies in these animals confirmed an increased area of periglomerular and intratubular fibrosis when compared to animals managed by either 1000 shocks or 2000 shocks in divided doses (p less than 0.01). These findings suggest the importance of avoiding single treatments with large doses of shock waves and favor the administration of multiple small-doses of shock waves to minimize renal damage during the treatment of patients with hard or large calculi.     

Endourologic treatment of nephrocalcinosis

Calcifications of the kidney may be located free within the collecting system, attached to a papilla, trapped beneath the urothelium, or sequestered in the renal parenchyma. Extracorporeal shock wave lithotripsy has failed to render patients who presented with nephrocalcinosis stone free because of the submucosal location of some of the calculi. We report a unique case of symptomatic nephrocalcinosis in which the patient was rendered stone free using flexible ureteroscopy and intrarenal laser and electrohydraulic lithotripsy to treat both the attached and submucosal papillary calculi.     

Ureteral stenting during extracorporeal shock wave lithotripsy: help or hindrance?

We retrospectively reviewed the outcome of extracorporeal shock wave lithotripsy in patients with renal calculi less than 3 cm. in size who were treated at a large multi-user lithotripsy center. Patients in whom indwelling ureteral stents were placed before lithotripsy treatment were subjected to higher levels of total power (shocks times voltage), yet the rate free of stones did not differ from those treated without a stent. In addition, the patients with internal ureteral stents experienced a significantly higher incidence of urinary urgency (43 versus 25 per cent) and hematuria (40 versus 23 per cent) than nonstented patients, respectively (p less than 0.05). Also, the duration of bladder discomfort was longer for stented patients (26 versus 13 per cent) as was the duration of urinary frequency (31 versus 16 per cent), compared to nonstented patients (p less than 0.05). The results suggest that use of an indwelling ureteral stent may not contribute to a higher rate free of stones for the treatment of small to medium sized renal calculi and, in fact, it may make the treatment more uncomfortable for the patient than performing lithotripsy without ureteral stenting. Of course, in selected cases (solitary kidney, large stone burden and aid in stone localization) ureteral stenting has a useful adjunctive role in extracorporeal shock wave lithotripsy.     

Treatment of renal stones in children: a comparison between percutaneous nephrolithotomy and shock wave lithotripsy

PURPOSE: We compared the results of percutaneous nephrolithotomy and shock wave lithotripsy for the treatment of 1 to 2 cm renal stones in children. MATERIALS AND METHODS: The study included 166 children with renal stones 1 to 2 cm. A total of 75 patients (82 kidneys) were treated with percutaneous nephrolithotomy and 91 (93 kidneys) were treated with shock wave lithotripsy. Mean followup was 31 +/- 10 months (range 6 to 84). Both groups were compared regarding stone-free rate, re-treatment rate, complications and incidence of stone recurrence. RESULTS: Both groups were comparable regarding preoperative characteristics. Of the units treated with percutaneous nephrolithotomy 4 (4.9%) were associated with minor complications. Stone-free rate after a single session of percutaneous nephrolithotomy was 86.6% (71 units), and the remaining 11 kidneys with residual stones were successfully treated with repeat percutaneous nephrolithotomy in 7 and shock wave lithotripsy in 4. Therefore, a total of 78 units (95%) were stone-free after percutaneous nephrolithotomy monotherapy, and the overall stone-free rate at 3 months was 100%. Of the patients undergoing shock wave lithotripsy 1 (1.1%) had development of steinstrasse and was successfully treated with ureteroscopy. The overall re-treatment rate after shock wave lithotripsy was 55%. A total of 79 units (84.9%) were stone-free after shock wave lithotripsy monotherapy, whereas 7 (7.5%) with no gross response to treatment were treated with percutaneous nephrolithotomy and 7 with insignificant stones less than 4 mm were followed. Therefore, the overall stone-free rate at 3 months was 92.5%. The differences in stone-free rates and re-treatment rates significantly favored percutaneous nephrolithotomy, while the incidence of complications and stone recurrence at last followup were not significantly different between the groups. CONCLUSIONS: For treatment of 1 to 2 cm renal stones in children percutaneous nephrolithotomy is better than shock wave lithotripsy, yielding higher stone-free and lower re-treatment rates.     

Shock wave lithotripsy at 60 or 120 shocks per minute: a randomized, double-blind trial

PURPOSE: The rate of shock wave administration is a factor in the per shock efficiency of shock wave lithotripsy (SWL). Experimental evidence suggests that decreasing shock wave frequency from 120 shocks per minute results in improved stone fragmentation. To our knowledge this study is the first to examine the effect of decreased shock wave frequency in patients with renal stones. MATERIALS AND METHODS: Patients with previously untreated radiopaque stones in the renal collecting system were randomized to SWL at 60 or 120 shocks per minute. They were followed at 2 weeks and 3 months. The primary outcome was the success rate, defined as stone-free status or asymptomatic fragments less than 5 mm 3 months after treatment. RESULTS: A total of 220 patients were randomized, including 111 to 60 shocks per minute and 109 to 120 shocks per minute. The 2 groups were comparable in regard to age, sex, body mass index, stent status and initial stone area. The success rate was higher for 60 shocks per minute (75% vs 61%, p = 0.027). Patients with larger stones (stone area 100 mm or greater) experienced a greater benefit with treatment at 60 shocks per minute. The success rate was 71% for 60 shocks per minute vs 32% (p = 0.002) and the stone-free rate was 60% vs 28% (p = 0.015). Repeat SWL was required in 32% of patients treated with 120 shocks per minute vs 18% (p = 0.018). Fewer shocks were required with 60 shocks per minute (2,423 vs 2,906, p <0.001) but treatment time was longer (40.6 vs 24.2 minutes, p <0.001). There was a trend toward fewer complications with 60 shocks per minute (p = 0.079). CONCLUSIONS: SWL treatment at 60 shocks per minute yields better outcomes than at 120 shocks per minute, particularly for stones 100 mm or greater, without any increase in morbidity and with an acceptable increase in treatment time.     

Clinical efficacy of high frequency jet ventilation during extracorporeal shock wave lithotripsy of renal and ureteral calculi: a comparison with conventional mechanical ventilation

The use of high frequency jet ventilation compared to conventional mechanical ventilation during general anesthesia for extracorporeal shock wave lithotripsy of renal or ureteral calculi can reduce stone movement. This decrease in stone movement theoretically lessens the total shock and energy requirements for stone fragmentation and perirenal tissue damage. To assess these theoretical advantages of high frequency jet ventilation, we studied patients undergoing extracorporeal shock wave lithotripsy to determine differences in stone movement during high frequency jet and conventional mechanical ventilation (30 patients), and in total shock requirements (1,174 patients). Mean stone movement in the 30 patients was 34.3 +/- 4.3 mm. during conventional mechanical ventilation compared to 4.1 +/- 1.9 mm. during high frequency jet ventilation (p less than 0.001). Mean total shocks were 1,542 +/- 212 (452 patients) during conventional mechanical ventilation compared to 1,217 +/- 165 (722 patients) during high frequency jet ventilation (p less than 0.001). Only 1 patient in the study had clinically significant perirenal tissue damage. We conclude that high frequency jet ventilation when compared to conventional mechanical ventilation results in clinically and economically beneficial decreases in total shocks for extracorporeal shock wave lithotripsy fragmentation of renal or ureteral calculi.     

Stepwise shock wave lithotripsy: Results of initial study for the treatment of urinary stones in childhood

Objective: To assess the effectiveness of stepwise extracorporeal shock wave lithotripsy in the treatment of upper urinary stones in childhood. Patients and methods: Between August 1998 and August 2003, 31 patients were treated for renal or ureteric stones. All treatments were performed with Dornier Compact Delta lithotripter. The number of shock wave was limited to maximum 3000 shock waves/session. The voltage was started at 10 kV and increased stepwise to 12.75 kV. Stone clearance was assessed at 3 months. The stone free state was defined as the absence of stone fragments. Results: Total 31 stones (24 renal and 7 ureteral stones) were treated. The age of the patients was median 8 (min–max: 0.8–12) years. The length of the stones was median 1 (min–max: 0.5–1.5) cm for renal stones and median 0.5 (min–max: 0.5–1) cm for ureteral stones. As an auxiliary procedure, open pyelolithotomy was required for 1 patient. The overall stone free rates for renal and ureter stones were 79% and 100%, respectively. Post-treatment insignificant hematuria was observed in all cases. Conclusion: Stepwise shock wave lithotripsy was an effective procedure for the treatment of urinary calculi in childhood.     

Extracorporeal shock wave lithotripsy in patients with a solitary kidney

Extracorporeal shock wave lithotripsy was used to treat 68 patients with renal calculi in a solitary kidney. Epidemiological information, including stone number, size and location, was similar to that of other patients treated with extracorporeal shock wave lithotripsy. Renal function as measured by serum creatinine changed negligibly in the majority of the patients. Three patients had transient serum creatinine elevations greater than 2 mg. per dl. that were caused by obstruction from stone fragments. There were 2 perirenal hematomas that required transfusion. One patient required retrograde manipulation of a ureteral stone before extracorporeal shock wave lithotripsy, while 6 required stone manipulations after therapy for steinstrasses. Of 59 patients evaluable after extracorporeal shock wave lithotripsy 58 (98.3 per cent) had a successful result: 38 (64.4 per cent) were completely free of stones and 20 (33.9 per cent) had clinically insignificant residual fragments. Extracorporeal shock wave lithotripsy is effective and safe in a solitary renal unit. We believe that in most patients it is the procedure of choice. Attention to fever, urine output and fragment size perioperatively is crucial.     

Extracorporeal shock wave lithotripsy monotherapy: experience with piezoelectric second generation lithotriptor in 642 patients

Extracorporeal shock wave lithotripsy monotherapy was performed in 642 patients for 1 year with an EDAP-LT01 piezoelectric lithotriptor. Of 642 patients 398 completed extracorporeal shock wave lithotripsy treatment and 244 still are undergoing multiple extracorporeal shock wave lithotripsy sessions. The 398 patients had renal (64.6 per cent) or ureteral (35.4 per cent) stones 0.6 to 4.8 cm. in diameter (mean 1.4 cm.). No general or regional anesthesia was required except in 7 children. Among 398 patients who completed extracorporeal shock wave lithotripsy the rate free of stones was 73.4 per cent and the rate of clinically insignificant residual fragments was 12.8 per cent. The success rate (rate free of calculi plus that of clinically insignificant renal fragments) ranged from 95.6 per cent for stones 0.6 to 1.0 cm. in diameter to 52.6 per cent for stones larger than 3.0 cm. (mean 86.2 per cent). The number of treatment sessions in 343 patients with successful results increased in accordance with the stone size, with an average of 1.6 sessions. Double-J* stents were placed in 7 patients and ureteral catheterization was performed in 11 as post-extracorporeal shock wave lithotripsy adjunctive measures. The steinstrasse phenomenon was noted in 14 patients, of whom only 1 required Double-J stenting. There were no significant complications. Therefore, extracorporeal shock wave lithotripsy monotherapy with the piezoelectric lithotriptor is considered to be a safe and efficient outpatient procedure for the initial treatment of urinary stones regardless of stone sizes.     

Extracorporeal shock wave lithotripsy in patients with cardiac pacemakers

Between May 1985 and July 1988, 11 patients with cardiac pacemakers were treated for renal or ureteral calculi by extracorporeal shock wave lithotripsy. During treatment and at follow-up no dysfunction of the pacemakers was noted. There were no cardiac complications during extracorporeal shock wave lithotripsy. All 11 patients were free of stones within 3 months after therapy. From these data it can be concluded that in patients with cardiac pacemakers extracorporeal shock wave lithotripsy of renal or ureteral stones can be performed safely when certain precautions are taken and special attention is paid to the electrophysiology of the pacemaker.     

Renal tubular damage after renal stone treatment

Summary 50 patients were studied with respect to renal tubular damage related to open operative, percutaneous and extracorporeal shock wave treatment of renal stones. Preoperative and postoperative urinary N-acetyl-glucosaminidase (NAG) levels were measured as a marker of renal damage. There was no significant evidence of renal tubular damage in patients who underwent a conventional or percutaneous nephrolithotomy; urinary NAG excretion was significantly increased after ischaemic surgery. After extracorporeal shock wave lithotripsy (ESWL) serum NAG levels increased, probably because a damage of the white blood cells in cutaneous and renal circulation, but a slight increase of urinary NAG excretion could suggest a mild renal tubular damage especially in case of more than 2,000 shocks.     

Multimodality treatment of complex renal calculi

More than 2,500 patients were treated for urolithiasis from 1984 to 1987. In an effort to define the relative role of extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy with respect to size, location and composition of the calculus 912 of these patients (224 of whom underwent percutaneous nephrolithotomy and 688 of whom underwent extracorporeal shock wave lithotripsy) were reviewed. Size proved to be the only significant factor in the success and complication rates of extracorporeal shock wave lithotripsy but it did not affect the outcome of percutaneous nephrolithotomy. The roles of these 2 modalities were then examined with respect to the treatment of complex renal calculi. We reviewed 376 patients with complex renal calculi, including 40 percutaneous nephrolithotomy patients from the initial 912 patients studied. The initial therapy in 100 of these patients, treated consecutively, was extracorporeal shock wave lithotripsy. The remaining 276 patients were treated by percutaneous nephrolithotomy. The success rate of extracorporeal shock wave lithotripsy monotherapy in the treatment of complex renal calculi was 36%. The success rate of primary percutaneous nephrolithotomy was 83%. We conclude that percutaneous nephrolithotomy should be the primary therapy for patients with complex renal calculi. Extracorporeal shock wave lithotripsy is the preferred treatment for patients with smaller calculi and as an adjunct to percutaneous nephrolithotomy.