Bacteriuria following extracorporeal shock wave lithotripsy of infection stones

Application of S.T.O.N.E. Nephrolithometry Score for Prediction of Stone-Free Status and Complication Rates in Patients Who Underwent Percutaneous Nephrolitotomy for Renal Stone

Background: Renal stone disease is a common disorder in urology practice. Kidney stone has various treatment methods such as extracorporeal shock wave lithotripsy, retrograde intrarenal surgery, and percutaneous nephrolithotomy (PCNL). In this study, we aimed to determine the value of S.T.O.N.E. nephrolithometry score, which is considered as a new scoring system for predicting residual stone rate and complications in patients undergoing PCNL due to renal calculi. Materials and Methods: A total of 120 patients >18 years old who underwent PCNL were evaluated prospectively. Five parameters available from preoperative noncontrast-enhanced computed tomography were measured: stone size (S), tract length (T), obstruction (O), number of involved calices (N), and essence or stone density (E) and then S.T.O.N.E. nephrolithometry score was calculated. The prediction of the stone-free rates and complication rates of this scoring was evaluated statistically. Results: When the age, gender, body mass index, comorbidities, and American Society of Anesthesiologists scores of the patients were evaluated according to the patients' postoperative stone-free status, no statistical difference was found between the groups. Patients had a stone-free rate of 78%. Patients' mean neuropilitometry score was calculated to be 7.75 S.T.O.N.E. nephrolithometry score statistically significant (P = .001) for prediction of stone-free status. S.T.O.N.E. nephrolithometry score was significantly correlated with operation time, estimated blood loss, duration of fluoroscopy, duration of hospital stay, and number of punctures. Complications were seen in 13 patients. Conclusions: S.T.O.N.E. nephrolithometry score can be used as an objective criterion for predicting the complexity of the PCNL process. In addition, this scoring system is expected to provide more objective preoperative counseling and can provide standardization in academic studies.

Management of Clinically Insignificant Residual Fragments following Shock Wave Lithotripsy

Clinically insignificant residual fragments (CIRFs) are small fragments (less than 5 mm) that are present in upper urinary tract at the time of regular post-SWL followup. The term is controversial because they may remain silent and asymptomatic or become a risk factor for stone growth and recurrence, leading to symptomatic events, and need further urologic treatment. Although a stone-free state is the desired outcome of surgical treatment of urolithiasis, the authors believe that the presence of noninfected, nonobstructive, asymptomatic residual fragments can be managed metabolically in order to prevent stone growth and recurrence. Further urologic intervention is warranted if clinical indications for stone removal are present.

Inactivation of bacteria inoculated inside urinary stone-phantoms using intracorporeal lithotripters

Intracorporeal lithotripsy is used to treat a high percentage of urinary calculi. Urinary calculi may contain bacteria, which might cause septicemia after lithotripsy; however, little is known about the effects of lithotripters on the viability of microorganisms inside renal calculi. The objectives of this study were to evaluate the bactericidal effect, and the potential effect on intra-bacterial protein release of four different intracorporeal lithotripters on Escherichia coli (E. coli) inoculated inside artificial kidney stones. An electrohydraulic, a pneumatic, an ultrasonic, and a holmium-laser lithotripter were used to pulverize a set of infected kidney stones inside a test tube containing a saline solution. Two different energy levels were tested per lithotripter. The stones were manufactured by mixing gypsum cement and Vel-mix-stone with a suspension containing E. coli. Results were analyzed by analysis of variance. The release of intracellular protein was measured with a spectrophotometer. Bacteria inactivation was observed with all lithotripters. The highest percentage of inactivated bacteria was obtained with the electrohydraulic lithotripter. The smallest effect was observed using the holmium-laser lithotripter. A relatively high amount of intracellular protein was released into the saline solution after stone pulverization. Intracorporeal lithotripters inactivate a high percentage of bacteria during stone comminution; however, intracellular protein is released, increasing the probability of septicemia.

Extracorporeal shock-wave lithotripsy monotherapy of partial staghorn calculi. Prognostic factors and long-term results

OBJECTIVE

To define factors affecting the success and long-term outcome of extracorporeal shock-wave lithotripsy (ESWL) monotherapy of partial staghorn calculi.

MATERIAL AND METHODS

We retrospectively reviewed 92 patients with partial staghorn calculi who were treated with ESWL monotherapy. The outcome of the treatment was evaluated after 3 months. Long-term follow-up data (>24 months) were available for 49 patients. These data were further analyzed to determine long-term outcome.

RESULTS

At 3 months, the overall stone-free rate was 59.8%. Multiple ESWL sessions were required in 85.8% of patients. Stone surface area>500 mm2 was the only factor that significantly decreased the stone-free rate. Post-ESWL complications occurred in 12 patients (13%), among whom renal obstruction was observed in 10.8%. Secondary procedures were needed in 17 cases (18.4%). After a mean follow-up period of 7.5 years, the stone-free rate was 59.2% (29/49) and one-third of patients developed recurrence. In the long term, clinically insignificant residual fragments (CIRFs) passed spontaneously in 23% of patients, remained stable in 38.5% and became bigger in 38.5%. Regrowth of CIRFs was related to a history of stone recurrence. No patients showed deterioration of kidney function on the treated side and an improvement in pre-ESWL hydronephrosis was observed in 73.3% of patients.

CONCLUSIONS

ESWL is suitable for staghorn stones<or=500 mm2. In the long term, CIRFs became bigger and required secondary intervention in one-third of patients. A history of stone recurrence is a significant predictor of regrowth of CIRFs. ESWL provides long-term preservation of function of the treated kidneys; however, one-third of patients develop recurrence.

Clinical Insignificant Residual Fragments (CIRF) after Extracorporeal Lithotripsy: Implications and Treatment

The stone-free status depends on the appropriate selection of the urologic treatment according to the stone and excretory tract characteristics, and/or to the patient parameters.

Although the gold standard for the treatment is the stone-free status, the authors believe that the presence of non-infected, nonobstructive, asymptomatic residual fragments, smaller than 4–5 mm, can be treated with an adequate medical therapy in order to prevent stone growth. Further urological treatment is recommended if the clinical indications for stone removal persist.

Shockwave lithotripsy for urinary stones in patients with urinary diversion after radical cystectomy

BACKGROUND AND PURPOSE

During recent years, survival of patients with invasive bladder cancer has been improved by early diagnosis and radical treatment. Urinary lithiasis is not rare in patients who have been submitted to radical cystectomy and urinary diversion. We have demonstrated the effectiveness and safety of SWL for these patients.

PATIENTS AND METHODS

We studied 11 patients who presented to our lithotripsy department suffering from urinary lithiasis after radical cystectomy. They were all cancer free at the time of treatment, and all underwent SWL on the Dornier HM-3 lithotripter as a first-line treatment. The mean stone burden was 1.85 cm(2), and the stone-to-patient ratio was 1:1.

RESULTS

The stone-free rate 1 month after SWL was 63.7%. Patients who were not stone free underwent a second SWL, and the stone-free rate after the second SWL session was 81.8%. We performed percutaneous nephrolithotripsy in one patient after the second SWL session because of the large stone burden remaining (3.2 cm(2)). The remaining patient was submitted to ureterolithotomy.

CONCLUSION

Application of SWL gives very good results in the treatment of urinary lithiasis in patients with a urinary diversion. Indeed, the results are equivalent to those achieved in patients without urinary diversion.

The physiologic approach to the medical management of stone disease

The cause of urinary stone disease can now be detected in approximately 80% of patients. Effective treatment can substantially reduce the recurrence of urinary calculi. Proper therapy depends on a thorough understanding of the physiology of calcium, oxalate, uric acid, cystine, and struvite formation and the medication developed for prevention. This article reviews the physiologic basis of urinary stone management in a straightforward, understandable fashion.

Incidence of urinary tract infection in patients without bacteriuria undergoing SWL: comparison of stone types

Extracorporeal shockwave lithotripsy (SWL) currently is accepted as the preferred treatment for most renal and upper ureteral calculi. However, little is known about the infection risks of SWL. In this study, the incidence and severity of urinary tract infection in 117 patients with renal calculi undergoing SWL were evaluated and the stone characteristics of those with and without infection were compared. The patients were followed clinically and bacteriologically 1 and 14 days after the procedure. Bacteriuria was noted in six patients within 24 hours after SWL. No bacteriuria was noted 2 weeks later. Of these patients, three were symptomatic (including dysuria, burning, and fever >38 degrees C). No patient was hospitalized. We found no significant correlation between the occurrence of bacteriuria and the number or size of the stones (P > 0.05), nor was there any correlation between bacteriuria and the stone-free rate or the location of the calculi (P > 0.05). However, there was a significantly higher risk of urinary tract infection in patients with struvite stones than in those with other types of stones (17.3% v 2.1%). In patients with infection stones, prophylactic antimicrobial chemotherapy is necessary even if bacteriuria is not present before SWL.

Spiral computed tomography for staghorn calculi

OBJECTIVES

To assess the utility of spiral computed tomography (CT) with three-dimensional reconstruction for preoperative planning of percutaneous nephrostolithotomy in patients with complex branched calculi (full staghorns).

METHODS

Patients with complex branched stones were imaged with spiral CT with three-dimensional reconstruction. These images were compared with standard imaging modalities, including excretory urography and plain radiographs, for planning percutaneous access for nephrostolithotomy. The utility of the scan was evaluated.

RESULTS

Ten patients with branched calculi were studied. Anatomic abnormalities were present in 5 patients. Excellent three-dimensional images were obtained in all patients without any complications related to the study. In 1 patient with multiple calculi in a horseshoe kidney, the three-dimensional image indicated a branched stone. The spiral CT scan was not helpful in directing percutaneous access in any patient. In a single patient, residual fragments noted during nephrostolithotomy were located by reference to the spiral CT scan.

CONCLUSIONS

Spiral CT scans with three-dimensional reconstruction provide three-dimensional imaging of branched renal calculi. This modality provides minimal additional information over that obtained from standard radiographic studies for guiding nephrostolithotomy and cannot be recommended as a routine preoperative study. It was helpful in 1 patient to locate a residual fragment.

A practical guide to the management of complicated urinary tract infection

Complicated urinary tract infections are infections in the setting of structural or functional abnormalities of the genitourinary tract. They encompass a wide variety of clinical syndromes and anticipated outcomes. The infecting micro-organisms isolated are more varied and demonstrate a higher prevalence of antimicrobial resistance in complicated compared to uncomplicated urinary tract infections. The usual duration of therapy is 7 to 14 days, although comparative trials to define optimal treatment duration are lacking. Long term success of antimicrobial treatment is dependent upon whether or not the underlying genitourinary abnormality can be corrected. Treatment of complicated urinary tract infections will usually be successful and may be permanent if the underlying abnormality can be corrected. If the underlying abnormality cannot be corrected, failure rates of 50% at 4 to 6 weeks following therapy are expected. Antimicrobial agents are similar to those used to treat uncomplicated urinary tract infection. Certain agents, such as nitrofurantoin, should be avoided for individuals with renal failure. No specific agent or class of agents has consistently demonstrated greater therapeutic efficacy where the infecting organism is susceptible to the given agent.

Treatment options in struvite stones

Urinary calculi have plagued man over the centuries. The epidemiology and pathogenesis of infection have been studied. The curative treatment remains problematic. Without therapy, a vicious cycle of stone formation occurs. This results in renal damage and even death. Multimodality therapy is the key. Nonoperative treatment leads to progressive renal damage. The combination of maximal surgical ablation and medical therapy is synergistic. The combination of PCNL-ESWL has not appeared to produce ill effects. PCNL-ESWL is a less morbid surgical alternative than open surgical procedures. Adjunctive medical therapy, such as culture-specific antibiotics and urease inhibitors, complements surgical ablation by reducing the morbidity with persistent UTIs and stone recurrence. The urologist today must approach struvite staghorns with a vast armamentarium of surgical and medical techniques. Each patient requires a unique solution.

Antimicrobial prophylaxis in management of urinary tract stones by extracorporeal shock-wave lithotripsy: is it necessary?

OBJECTIVES

In a prospective randomized study, we evaluated the incidence of urinary tract infections following extracorporeal shock-wave lithotripsy (ESWL) and the necessity of prophylactic antibiotic administration in patients treated with this modality.

METHODS

A total of 360 consecutive patients with renal and ureteric stones who had sterile urine before ESWL treatment and did not have any increased risk of infection received either a single dose of 400 mg of ofloxacin or no prophylaxis. Patients were followed by simple urine analysis and urine cultures together, with clinical evaluations.

RESULTS

Only 3 patients (0.8%) had positive urine cultures at 1 week after ESWL. Two of these patients were in the antibiotic prophylaxis group.

CONCLUSIONS

The incidence of urinary tract infections after ESWL is extremely low, provided that patients have sterile urine before ESWL, and prophylactic antibiotics are not required.

Selective minimally invasive management of calculi in patients with urinary diversions

We evaluate the efficacy of selectively applied minimally invasive management of calculi in 30 patients with urinary diversions (ileal/jejunal conduit in 23, cutaneous ureterostomy in 2, nonrefluxing colon conduit in 4 and ureterosigmoidostomy in 1). Upper tract calculi in 38 renal units were managed with extracorporeal shock wave lithotripsy or endo-urologically. Patients were divided into 3 treatment groups determined primarily by stone size and location: group 1-25 renal units with a mean stone burden of 1.78 cm.2 treated with extracorporeal shock wave lithotripsy alone, group 2-7 renal units with a mean stone burden of 12.75 cm.2 treated with percutaneous nephrostolithotomy alone and group 3-6 renal units with a mean stone burden of 19.03 cm.2 treated with a combination of both procedures. Stone-free results were 92%, 100% and 67% in groups 1 to 3, respectively. Total hospital stay averaged 4.3, 11.1 and 13.7 nights, while complications occurred in 1, 3 and 2 patients, respectively. We conclude that selective application of contemporary techniques for minimally invasive management of calculi in patients with a urinary diversion can provide acceptable results, even with progressively large and complex stone burdens, and that these results will be equivalent to those achieved in patients without urinary diversion.

Effect of alkaline citrate therapy on clearance of residual renal stone fragments after extracorporeal shock wave lithotripsy in sterile calcium and infection nephrolithiasis patients

The natural history of post-extracorporeal shock wave lithotripsy residual stone fragments (clearance, growth and aggregation) is incompletely known, even though they are believed to constitute a risk in terms of new stone formation and persistent infection of the urinary tract. We addressed this issue and the hypothesis that alkaline citrate therapy improves residual stone fragment clearance in a 12-month followup study. There were 40 sterile calcium and 30 struvite stone patients with residual fragments after extracorporeal shock wave lithotripsy (diameter less than 5 mm.) consecutively enrolled and randomly assigned to a citrate therapy (6 to 8 gm. per day) or control (hygienic measures only) group. Infection stone patients also received adequate antibiotic therapy throughout the study. Among the patients in the untreated sterile group 21% and 32% were stone-free at 6 and 12 months, respectively. In the infection group these figures were 27% and 40%, respectively. Among the untreated sterile calcium stone patients in whom clearance was not achieved a high percentage experienced residual fragment growth or reaggregation. Citrate therapy significantly improved the stone clearance rate in the sterile (at 6 and 12 months 65% and 74% were stone-free, respectively) and infection (71% and 86%, respectively) stone patients, and prevented residual fragment growth or reaggregation in subjects in whom clearance was not achieved. The data show that growth and persistence are common in the natural history of residual stone fragments. Citrate ameliorated the outcome of these residual fragments by reducing the growth or agglomeration, and by increasing the clearance rate in calcium oxalate and in infection stone patients.

Incidence of bacteremia and bacteriuria in patients with non-infection-related urinary stones undergoing extracorporeal shock wave lithotripsy

In a prospective pilot study, 26 patients with non-infection-related renal or ureteric stones and sterile urine were examined for evidence of bacteriuria and bacteremia following extracorporeal shock wave lithotripsy (SWL). Blood samples were obtained for aerobic and anaerobic bacterial culture at the end of, and 1 hour after, the SWL procedure. Urine cultures were performed 24 hours before and after treatment. Bacteremia was recorded in 7.7% of the patients immediately after SWL but in no patient at 1 hour after treatment. None of the patients manifested significant bacteriuria or post-SWL fever. These findings support the contention that, provided the urine is sterile and a negative history of urosepsis is available, antibiotic prophylaxis is unnecessary in patients with non-infected renal stones submitted to SWL treatment.

Risk of bacteraemia during extracorporeal shock wave lithotripsy

Extracorporeal shock wave lithotripsy (ESWL) is widely used to treat urinary calculi. With increasing numbers of ESWL, more patients prone to infectious complications will be treated. However, little is known about the infectious risks of ESWL. To provide a basis for the rational use of antimicrobial prophylaxis, we studied the incidence of bacteraemia during ESWL. A total of 23 patients with urinary calculi were treated. Blood cultures (4-7 per patient) were taken before, during and immediately after ESWL, adding up to a total of 154 cultures. In 22 of these patients no bacteraemia was detected. In 1 patient small numbers of 2 different micro-organisms were found in 2 blood samples only. This finding, and the circumstances of blood collection, suggested contamination rather than bacteraemia. It was concluded that the risk of bacteraemia during ESWL is very low.

London after Tomlinson. Care in the capital: what needs to be done

One of the aims of the Tomlinson report is to shift more care from the secondary to the primary sector in London. But the primary sector is already underresourced and overloaded. The capital has a heterogeneous population which often makes inappropriate demands on general practitioners. Many premises are inadequate and there are insufficient support staff. David Metcalfe emphasises that London is special and that the shift will not become a reality unless these problems are tackled. He suggests the establishment of different models of practice centres which could treat some of the patients who now go to accident and emergency departments. Some would be the night emergency service base, some would have primary care beds, and each would have a different mix of specialist support.

Diagnosis and management of urinary tract infection in adults

Images

Extracorporeal shock wave lithotripsy retreatment ("stir-up") promotes discharge of persistent caliceal stone fragments after primary extracorporeal shock wave lithotripsy

A prospective randomized study was performed to compare the results of piezoelectric extracorporeal shock wave lithotripsy (ESWL) retreatment versus surveillance only in 50 patients with persistent caliceal stone fragments after primary ESWL for renal calculi. After a 3-month followup significant decreases in residual debris were observed in the retreated group, while changes in the control group were negligible. Considering the low morbidity of outpatient ESWL with a pain-free, second generation lithotriptor, ESWL retreatment of completely fragmented but persistent stone debris appears to be justified to render the kidney stone-free.

Staghorn calculi: analysis of treatment results between initial percutaneous nephrostolithotomy and extracorporeal shock wave lithotripsy monotherapy with reference to surface area

Treatment recommendations and results reported for the management of staghorn calculi are highly variable. In an attempt to provide a more objective means to compare treatment results for staghorn renal calculi, stone burden as measured by stone surface area was used. Stone surface area was determined by computer analysis. A total of 380 cases of staghorn calculi treated at the same institution was evaluated. Treatment consisted of initial percutaneous nephrostolithotomy with or without extracorporeal shock wave lithotripsy (ESWL*) in 298 cases and ESWL monotherapy in 82. When considered as a group, the overall stone-free rate for initial percutaneous nephrostolithotomy (mean surface area 1,378.3 mm.2) was 84.2% compared to 51.2% (p less than 0.0001) for ESWL monotherapy (mean surface area 693.4 mm.2). For staghorn calculi smaller than 500 mm.2 a stone-free rate of 94.4% was achieved in the percutaneous nephrostolithotomy with or without ESWL group compared to 63.2% for ESWL monotherapy (p = 0.0214). For calculi of 501 to 1,000 mm.2 the stone-free rates were 86% and 45.7%, respectively (p less than 0.0001). When stone surface area exceeded 1,000 mm.2 the stone-free rate for percutaneous nephrostolithotomy with or without ESWL was 82.4% but it was only 22.2% for ESWL monotherapy (p = 0.0002). Overall, when adjusted for stone surface area the odds of being stone-free were more than 8 times higher for initial percutaneous nephrostolithotomy versus ESWL monotherapy (odds ratio = 8.36, p less than 0.0001). While percutaneous nephrostolithotomy with or without ESWL appears to be the procedure of choice for most staghorn stones, ESWL monotherapy may have a role for some stones smaller than 500 mm.2. In 12 such cases associated with a nondilated renal collecting system (mean surface area 380.5 mm.2) a stone-free rate of 91.7% was achieved. The number of procedures required to complete therapy was higher in the initial percutaneous nephrostolithotomy group (2.8 versus 2.1, p less than 0.0001). Although complications were more common in the ESWL monotherapy group (manifested as obstruction in 30.5%), bleeding requiring blood transfusion was more frequent in the initial percutaneous nephrostolithotomy group (9.4%).

Long-term efficacy of combination therapy for struvite staghorn calculi

A total of 28 patients with extensive struvite staghorn calculi underwent endourological sandwich therapy consisting of primary percutaneous debulking followed by extracorporeal shock wave lithotripsy (ESWL*) of residual stone fragments. Secondary percutaneous procedures, ESWL treatments and 10% hemiacidrin irrigations were used as necessary specifically to achieve a stone-free renal unit. With 12 to 55 months (mean 31 months) of followup, during which time regular surveillance was done and antibiotic prophylaxis was used routinely, renal function remained stable or improved in 93% of the patients, including 4 with a solitary kidney. Infection has recurred or persisted in 30% of the patients, while stones recurred in 22%. We conclude that an aggressive, combined endourological approach to the management of struvite staghorn calculi can achieve long-term results comparable to standard operative intervention.

The effect of isolated high-energy shock wave treatments on subsequent bacterial growth

To determine whether high-energy shock waves possess bactericidal potential, ATCC strains of Escherichia coli, Streptococcus faecalis, Pseudomonas aeruginosa and Staphylococcus aureus were suspended in solution at concentrations approximating 10(6) bacteria per milliliter, placed in polypropylene cryovials, and immersed in the water bath of a Dornier HM3 lithotriptor. Each cryovial was then fluoroscopically guided to the epicenter of the f2 focal point and 2000 shocks at 20 kV applied. Suspensions were then serially diluted and colony counts obtained. The procedure was then repeated with 4000 shocks at 20 kV from the Dornier HM3 and 4000 shocks at intensity level 4 from a Wolff Piezolith 2200 shock wave lithotriptor. Comparison of shock-wave-treated and sham-treated bacterial suspensions revealed no significant difference in bacterial growth according to the colony count technique. We conclude that high-energy shock waves, whether generated by spark gap or piezoelectric array, do not possess significant bactericidal activity.

Prospective study of post-ESWL infections of the urinary tract

Throughout the world ESWL is nowadays the treatment of choice in renoureteral stones and ever smaller stones can be treated. We have undertaken the present study to evaluate post treatment infective complications in low-risk patients. A prospective study has been performed on 150 non-infected patients before ESWL treated for renal stones whose maximum diameter was less than 15 mm. None out of this group underwent pretreatment manoeuvres. Urinecultures were checked before and after treatment (3 days – 30 days). Out of 150 third day urine cultures 11 were positive but only 5 patients presented a symptomatic infection. All patients whose urineculture was positive received antibiotic treatment. All urinecultures were negative at the 30 days follow-up. The low incidence of urinary symptomatic and asymptomatic infections in our series and the rapid cure by antibiotic therapy suggest performing ESWL treatment in selected patients without any antibiotic prophylaxis. Antibiotic therapy will be set up just in symptomatic or asymptomatic post-treatment infections.

Extracorporeal shock wave lithotripsy for struvite renal calculi: prospective study with extended followup

To clarify the significance of retained stone particles after extracorporeal shock wave lithotripsy (ESWL) for struvite renal calculi we followed 22 otherwise healthy women for 16 to 52 months (mean 39 months). Each patient had persistent Proteus mirabilis bacteriuria before ESWL and received a standardized regimen of antimicrobial therapy in the perioperative period only. Of the 22 patients 19 (86%) were cured of the persistent bacteriuria. Of these 19 patients 16 had retained stone particles at the beginning of surveillance and 10 had retained particles at last followup. None of the particles produced symptoms or enlarged. However, 1 of the patients who was rendered stone-free had a P. mirabilis reinfection at 20 months and a new stone developed. Of the 22 patients 3 (14%) had continued persistent P. mirabilis bacteriuria after ESWL. Two patients were subsequently cured of the infection with antibiotics alone (1), and with antibiotics and extraction of a new ureteral stone (1). The remaining patient had expansion of retained stone particles after 51 months of surveillance. We conclude that a stone-free kidney is an unrealistic objective of ESWL monotherapy for struvite renal calculi. However, the treatment usually will eradicate the accompanying persistent bacteriuria and sterile stone particles will not enlarge during the first 2 to 4 years after treatment.

A comparison of anatrophic nephrolithotomy and percutaneous nephrolithotomy with and without extracorporeal shock wave lithotripsy for management of patients with staghorn calculi

A retrospective study was conducted comparing anatrophic nephrolithotomy (10 cases), percutaneous nephrolithotomy alone (4 cases) or percutaneous nephrolithotomy combined with extracorporeal shock wave lithotripsy (23 cases) for the treatment of large staghorn calculi. A comparison based on collecting system anatomy demonstrated that anatrophic nephrolithotomy resulted in a greater stone-free rate, shorter hospitalization and lower costs while complication rates were similar. Anatrophic nephrolithotomy should still be considered a viable treatment option, especially for patients with large branched calculi in complex collecting systems.

Effect of extracorporeal shock wave lithotripsy on bacterial viability. Relationship to the treatment of struvite stones

The aim of this study was to determine whether extracorporeal shock wave lithotripsy (ESWL) affected the viability of the infecting bacteria within a simulated struvite stone matrix. A strain, Proteus mirabilis 28cii, was prepared in three forms: (1) suspended in saline and urine, (2) artificially encapsulated by suspending in agar beads and (3) artificially encapsulated and mineralised by suspending in agar beads with calcium carbonate crystals. The preparations were placed in capped vials partially immersed in degassed water and held in the focal point of the Siemens Lithostar and given 1,000 shocks. Subsequent viability testing showed that bacteria suspended in urine were greatly affected by shock treatments (55% loss in viability), but incorporation into agar beads negated this effect (even if the cells were exposed to 2000 shocks). Mineralisation of the beads with calcium carbonate crystals caused a decrease in viability of 82% that was significantly different from controls. However, this still left 2.3 X 10(8) viable organisms (82% of 2.8 X 10(8], easily enough to form the focus for further infections. A series of control experiments carried out using an ultrasonic cell sonicator probe gave comparable results to those obtained with ESWL. These results demonstrate the ESWL treatment of infected stones must be accompanied by antimicrobial coverage.

The effect of extracorporeal shock wave lithotripsy on the microbiological flora of urinary calculi

To determine whether extracorporeal shock wave lithotripsy can sterilize infection stones and, thus, decrease the recurrence rate we investigated its impact on the microbiological flora of staghorn calculi. Fragments from 17 staghorn calculi retrieved percutaneously were divided into paired sets. One set was fractured by extracorporeal shock wave lithotripsy at 18 kv. and with increasing numbers of shock waves up to 1,000. One set was fractured mechanically with a surgical clamp. Bacterial cultures were then compared between the 2 groups. Of the 17 staghorn calculi 10 showed significant bacterial growth (59%). The number of colony-forming units was not significantly different between stones fragmented by lithotripsy and those that were mechanically fractured. Furthermore, exposing fragments to an increasing number of shock waves did not alter the colony count. We conclude that extracorporeal shock wave lithotripsy has no discernible effect on the microbiological flora of infected staghorn calculi.

ESWL monotherapy for large-volume renal calculi: efficacy and morbidity

We assessed the efficacy and morbidity of extracorporeal shock-wave lithotripsy (ESWL) monotherapy in the treatment of 25 consecutive patients with large-volume renal calculi (surface area greater than or equal to 5.0 cm2). Eighteen of the calculi were infection (struvite) stones and 7 were sterile stones. In 21 cases internal ureteral stents were positioned before ESWL, but no patient underwent pretreatment percutaneous nephrostomy (PCN) or percutaneous nephrostolithotomy (PNL). An average of 2.1 procedures including ESWL, PCN, or ureteral interventions were required to achieve a stone-free renal collecting system and ureter, or residual stone particles less than 4 mm in diameter confined to the renal collecting system. Sixty percent of the patients required no ancillary procedures after ESWL. There were no differences in the mean duration of hospitalization, need for post-treatment ancillary procedures, time to clearance of ureteral fragments, and incidence of residual stone particles among patients with infection and sterile stones. Of 23 patients observed greater than three months (mean 10.9 mos) after ESWL, 43 percent had residual stone particles in the renal collecting system. Expansion of these particles or stone recurrence in the absence of residual particles has not been observed. We conclude that large volume renal calculi may be managed effectively and safely with ESWL monotherapy.

[Antibiotic prophylaxis with enoxacin in extracorporeal shockwave lithotripsy]

According to literature, 16 to 35% of operatively removed renal stones harbour bacteria. The efficacy of antibiotic prophylaxis with enoxacin in reducing the rate of bacteriuria after extracorporeal shock wave lithotripsy (ESWL) was investigated in a prospective randomized study. Twenty-five patients received a single 400 mg dose of enoxacin one hour before ESWL, 25 patients did not receive an antibiotic. It was found that a single 400 mg dose of enoxacin one hour before ESWL can reduce the rate of bacteriuria significantly.