The Medstone fixed, mobile, and modular configurations: impact on efficacy

PURPOSE: To evaluate the efficacy of three lithotripter configurations that utilize the Medstone STS treatment head. PATIENTS AND METHODS: From 1999 through 2002, 13,131 patients were treated with the Medstone STS fixedsite unit (STS-FIX; 52%), the mobile coach-transportable unit (STS-MOB; 26%), or the modular operating-room unit (STS-T; 22%). All units were staffed by a rotating schedule of the same ten SWL-certified radiological technicians. The treating urologists reported follow-up that included plain abdominal radiography to document stone-free rate (no residual fragments) and the need for auxiliary procedures or re-treatment. An efficiency quotient (EQ) was calculated for each unit. RESULTS: The overall stone-free rate for the STS-FIX, STS-MOB, and the STS-T was 59%, 62%, and 65%, respectively. The STS-FIX had the lowest stone-free rate for lower-pole stones (48%) and stones 21 mm to 30 mm (30%) compared with the STS-MOB (57% and 62%, respectively) and the STS-T (59% and 54%, respectively). However, the STS-FIX had a higher stone-free rate in the middle ureter (86%) than the STS-T (67%) and STS-MOB (65%). The STS-FIX required more post-SWL procedures overall (12%) than the STSMOB (4%) and STS-T (5%). The re-treatment rates for the STS-FIX, STS-MOB, and STS-T were 7%, 6%, and 6%, respectively. The STS-T had the highest overall EQ (59) followed by the STS-MOB (56) and the STSFIX (50). CONCLUSIONS: New configurations of the STS lithotripter have a significant positive impact on efficacy compared with the original fixed machine. Availability of real-time fluoroscopy with the STS-T may impact the higher EQ of this machine.     

Anesthesia for extracorporeal shockwave lithotripsy: Teikyo University Hospital experience using the third generation lithotripter

A single-board certified urologist with training and experience in anesthesiology was assigned to treat 502 patients (185 with renal stones, 317 with ureteral stones) using the Dornier Compact Delta lithotripter under general or epidural anesthesia. Data were obtained regarding stone location, stone size, shockwave use, stone-free rate, and complications. In all, 502 stones were treated with the Dornier Compact Delta lithotripter. Among renal stones, 73% were in the renal pelvis. Among ureteral stones, 60% were in the upper, 10% in the middle, and 30% in the lower ureter. Diameters of 61.8% of stones were less than 1 cm. The mean number of shocks was 3,471 at a mean power setting of 5. The stone-free rate for renal stones was 71.5%, while for ureteral stones this reached 99%. The efficiency quotient was calculated as 0.65. One patient with a renal stone developed perinephric hematoma requiring 3 units of transfusion. With a success rate higher than that reported for other lithotripters, the Dornier Compact Delta lithotripter represents a feasible treatment for urolithiasis. We stress that even in the third generation machines the lithotripsy under anesthesia can improve the treatment efficacy.     

Impact of shockwave coupling on efficacy of extracorporeal shockwave lithotripsy

PURPOSE: To evaluate the impact of a slow gated treatment rate on the efficacy of extracorporeal shockwave lithotripsy (SWL). PATIENTS AND METHODS: From August 1990 to July 2002, 40,462 SWL procedures were performed using the slow frequency electrocardiography (ECG)-gated lithotripter (82.5%) and fast frequency ECG-ungated (17.5%) modes for the Medstone STS lithotripter. Treatment characteristics, including the mode of SWL, location and size of the stone, re-treatment status, auxiliary procedures required, perioperative complications, and treatment outcomes, were recorded. The stone-free rate was reported by the treating physician on the basis of the finding of no residual stone fragments on a plain radiographic image. RESULTS: The treatment rate for the slow mode was a mean of 79.6 shocks/min, while the rate for the fast mode was 120/min. The total procedure time was 47.0 minutes for the slow mode and 40.6 minutes for the fast. The overall stone-free rate was higher for slow (66.9%) than fast (63.6%) procedures (P < 0.001). The stone-free rate for 1- to 10-mm stones was higher for the slow procedures (75.7%) than the fast procedures (70.7%; P < 0.001). Upper-ureteral stones responded better to slow treatment in terms of stone-free rate (79.5% v 72.6%; P < 0.001), re-treatment rate (6.5% v 8.0%, P = 0.05), auxiliary-procedure rate (6.1% v 8.9%; P = 0.01), and efficiency quotient (71 and 62). There was no significant difference in complication rates overall between slow and fast treatment. CONCLUSIONS: With a minimal increase in procedure time, greater efficacy can be obtained for the treatment of radiopaque stones with a slower shock-delivery rate. In particular, upper-ureteral calculi and calculi <10 mm benefit from a slower treatment rate.     

A new transportable shock-wave lithotripsy machine for managing urinary stones: a single-centre experience with a dual-focus lithotripter

OBJECTIVE: To assess the efficacy and safety of a transportable extracorporeal shock wave lithotripsy (ESWL) machine, the Modulith SLX-F2(TM) (Storz Medical Italia, Rome, Italy), in the management of solitary urinary calculi. PATIENTS AND METHODS: The study included 233 patients (mean age 51 years; 172 male, 61 female) with symptomatic solitary renal (group A, 170, mean diameter 15.5 mm) or ureteric stones (group B, 63, mean diameter 9.5 mm) treated in a tertiary care institution. Exclusion criteria for the analysis were: pelvi-ureteric junction obstruction, multiple stones, stone diameter >2 cm, stones in a lower calyx with unfavourable anatomy, active infection, or impacted ureteric stones. Selected patients had ureteric stenting before treatment, and all patients were treated with no anaesthesia. Hospitalization, complications and subsequent auxiliary procedures were evaluated. Patients were assessed after a single ESWL session and after 3 months by a plain abdominal film and renal ultrasonography. Stone-free status was defined as no evidence of calculi, and clinical success as the presence of stone fragments of <4 mm. An efficiency quotient (EQ) was calculated for the ESWL treatment. Pain was assessed using a visual analogue scale. RESULTS: The mean number of shocks used was 3779 and the mean (range) treatment time was 35 (5-55) min. The overall clinical success rate after one ESWL session was 83.7% and 82.5% for renal and ureteric stones, respectively, and the overall 3-month stone-free rate was 77% and 74.6%, respectively; the overall EQ was 0.64. When risk factors for persistent calculi were analysed simultaneously in a logistic regression model, only stones of >1 cm were statistically significant (P < 0.05). Most patients reported that pain during ESWL was mild to moderate and easily tolerated. Only minor complications occurred, with an overall complication rate of 3.8%. CONCLUSIONS: This transportable lithotripter is a safe and effective device for managing solitary stones throughout the urinary tract. Its main advantage is represented by the dual-focus system. Moreover, it shares with other contemporary machines several important features such as outpatient setting, no need for anaesthesia, easy patient positioning, and the capability of ancillary procedures.     

Clinical experience with a new ultrasonic and LithoClast combination for percutaneous litholapaxy

OBJECTIVE: To assess a new lithotripter for intracorporal lithotripsy, which combines the mechanically driven pneumatic LithoClast (Electro-Medical Systems, Nyon, Switzerland) and a new ultrasonic device (Electro-Medical Systems), for use in percutaneous nephrolitholapaxy (PNL). PATIENTS AND METHODS: The new lithotripter consists of a LithoClast Master with 12 Hz repetition rate and a new ultrasonic device. The 1.0 mm LithoClast probe is advanced off-centre through the hollow 3.3 mm ultrasonic probe and protrudes about 1 mm. A new irrigation system with a pinch valve compressing the irrigation tube, a foot-switch for activating the ultrasound, the LithoClast and both together, and a stone bucket at the outlet tube are new features. Between February 1999 and August 2001, 68 patients were treated by PNL with the new device; 35 had complete and 33 had partial staghorn calculi. PNL was administered under fluoroscopic control and with the patient prone. RESULTS: The mean (range) duration of surgery was 61 (42-119) min. The complete stone-free rate was 66% after the first PNL; of the 68 patients, 16 received a second PNL, giving a final stone-free rate of 76% and 80%. The stone was composed of calcium oxalate monohydrate (COM) in 13%, COM with uric acid in 35%, apatite in 20% and cystine in 11%. Clinically the new lithotripter was very effective, producing smaller stone particles and thus fewer residual stone fragments after PNL than with the LithoClast or ultrasonic fragmentation alone. CONCLUSION: The new lithotripter provides easily managed and highly effective stone fragmentation of all stones, regardless of their composition.     

Impact of type of anesthesia on efficacy of medstone STS lithotripter

PURPOSE: To evaluate the impact of the type of anesthesia on treatment efficacy, using a comparison of general anesthesia (GEN) and monitored anesthesia care with intravenous sedation (MAC), for patients undergoing extracorporeal shockwave lithotripsy (SWL) on the Medstone STS lithotripter. PATIENTS AND METHODS: A case-control study was conducted of 660 patients treated from 1986 to 2002. General anesthesia and MAC were utilized in 330 procedures each. Case matching was performed for stone size, stone location, and body mass index. All lithotripter units were staffed by a rotating schedule of the same 10 SWL-certified radiologic technicians. Patient characteristics, treatment parameters, complications, repeat procedures, and secondary procedures were recorded. Stone-free success rates (no residual fragments) were reported by the treating physician on the basis of plain radiographs. Chi-square analysis was used to compare patients in the two groups. RESULTS: The overall stone-free rate was better with GEN (67%) than MAC (55%; P = 0.04). Stone-free rates were not affected for stones 10 mm or in an upper calix. General anesthesia may decrease excursion of the calculus out of the focal area secondary to breathing or patient movement.     

The effect of intracalyceal distribution on the clearance of renal stones of > or = 20 mm in children after extracorporeal lithotripsy

OBJECTIVES: To determine the effect of the intracalyceal distribution of renal stones on clearance rates after treating paediatric nephrolithiasis with extracorporeal shock wave lithotripsy (ESWL). PATIENTS AND METHODS: We assessed a retrospective case series of children (aged < or = 14 years) undergoing lithotripsy on an MPL 9000 (Dornier GmbH, Germany) echo-guided lithotripter. Patients were identified using an international coding and indexing system and ESWL registry. In all, 125 children were treated during 1990-2003, but 21 had stones of > or = 20 mm. Stone clearance was assessed at 1 and 3 months, the stone-free state being defined as no radiological evidence of stone or fragments of < or = 3 mm. Failed treatments were analysed to identify any correlation with stone site. RESULTS: The overall stone-free rate was 81%; in four children the treatment failed (all girls) and subsequently they required ancillary procedures. Nineteen patients (90%) received up to three sessions of ESWL; two required four or more sessions. Of the four children in whom treatment failed, two had JJ stents; the stones were in the lower pole calyx in two, and the renal pelvis and lower pole calyx in two. The mean stone size in those where treatment failed was 25 mm, vs 21 mm in the stone-free group. The complication rate was 19%, but only one child required admission to hospital. CONCLUSIONS: ESWL is very effective for renal stones in children, with minimal morbidity. Lower pole and partial staghorn stones with a major component in the lower pole calyx should preferably be treated by a percutaneous approach.     

Flexible ureteroscopic lithotripsy: first-line therapy for proximal ureteral and renal calculi in the morbidly obese and superobese patient

BACKGROUND AND PURPOSE: The surgical treatment of kidney and proximal ureteral stones in morbidly obese patients (>14 kg/m2) remains difficult because shockwave lithotripsy is precluded by weight limitations and percutaneous nephrolithotomy is associated with difficult access and a high (9%) rate of transfusion. We review our experience with retrograde ureteroscopic lithotripsy in morbidly obese patients with renal and proximal ureteral stones. PATIENTS AND METHODS: Between December 1992 and April 2000, five women and three men with a mean age of 46.5 years (range 33-68 years) and a mean body mass index of 54 (range 45-65.2) underwent 10 independent ureteroscopic procedures for urolithiasis. The average stone size was 11.1 mm (range 5-25 mm). Lithotripsy was performed with the holmium laser in eight patients (60%) the electrohydraulic lithotripter in four (30%), and the tunable-dye laser in the remaining patient. Stone-free status was defined as no stones visible on a plain film with nephrotomograms or CT scan at 3 months. RESULTS: The mean operation time was 101 minutes (range 45-160 minutes), and 60% of the procedures were done on an outpatient basis. After the initial procedure, the stone-free rate was 70%. Two patients had fragments <4 mm, and no further therapy was undertaken. There was one complication: transient renal insufficiency (serum creatinine concentration 3.7 mg/dL) secondary to aminoglycoside toxicity. No transfusions were needed. CONCLUSION: In the morbidly obese patient with symptomatic stones <1.5 cm, ureteroscopic lithotripsy is safe, successful, and efficient.     

Outcome and safety of extracorporeal shock wave lithotripsy as first-line therapy of lower pole nephrolithiasis

INTRODUCTION: The aim of this study is to assess the efficiency of extracorporeal shock wave lithotripsy (ESWL) as initial therapy for isolated lower pole kidney stones smaller than 20 mm. PATIENTS AND METHODS: During a 24-month period 116 patients with previously untreated single stones under 20 mm in diameter were treated with a Dornier lithotripter S. They were analyzed with regard to stone site and size, number of ESWL sessions, auxiliary measures, retreatment rates, complications and the time taken for stone clearance. RESULTS: 76 patients (65.5%) became stone free, 50 of them (43.1%) within 3 months after ESWL. Depending on stone size the stone-free rates were 67.1% for patients with a stone diameter of <10 mm (59 of 88 patients), and 60.7% for stone diameters between 10 and 20 mm (17 of 28 patients). Complications during and after treatment were rare, i.e. the necessity of ureteral stent insertion due to colic (n = 10), endoscopic stone removal (n = 2), acute pyelonephritis (n = 1), stonestreet (n = 1) and 1 case of hematoma not requiring intervention. The recurrence rate during follow-up (13.2-36.9, mean 25.0 months) was low: 16 patients (13.8%) had recurrent or persistent stones, and 74 patients (63.8%) had no evidence of urolithiasis. CONCLUSIONS: ESWL is a safe and efficient first-line therapy for treatment of isolated small lower pole kidney stones with acceptable stone-free rates, low morbidity, few complications and a low stone recurrence rate.     

Monotherapy with extracorporeal shock wave lithotripsy for renal and ureteral stones]

We performed extracorporeal shock wave lithotripsy (ESWL) as a monotherapy using the Medstone STS lithotripter on 288 patients with renal and ureteral stones between June, 1989 and June, 1991. We compared our results with previous reports on ESWL as used in combination therapy. Our cases consisted of 121 patients with renal stones and 167 patients with ureteral stones. A total of 437 sessions of lithotripsy were performed on 288 patients, for an average of 1.52 sessions of lithotripsy per patient. The percentage of stones measuring less than 4.0 mm in diameter that were fragmented was 94.3% for renal stones and 87.6% for ureteral stones. The stone-free rates 3 months after ESWL were 60.3% and 90.4%, respectively. Our results of the monotherapy with ESWL did not differ from those reported on ESWL as used in combination therapy, in terms of the rate of stone destruction and stone-free rates. We studied the other reports carefully and determined that ESWL monotherapy could have been performed in most those cases. We concluded that ESWL monotherapy is an excellent therapeutic method in the light of fewer complications and side effects compared with those from combination therapy, and the fact that the rate of recurrence for renal and ureteral stones is high makes ESWL monotherapy very useful because the procedure can be repeated.     

Minimally invasive treatment of infection staghorn stones with shock wave lithotripsy and chemolysis

We report the results in 118 patients with infection staghorn stones treated with an anaesthesia-free minimally invasive method that combined repeated shock-wave lithotripsy (SWL) sessions (unmodified Dornier HM3 lithotripter) and percutaneous chemolysis with Renacidin. The stone-free rate was 60%. In 27 consecutive patients with infection staghorn stones representative of patients with this stone type in the population, a stone-free rate of 77% was recorded. The latter figure is comparable with results reported for open surgery, percutaneous surgery and sandwich therapy, and superior to that recorded with SWL alone. During the study period, no patient referred to us with an infection staghorn stone was treated with percutaneous, ureteroscopic or open surgery, and all treatments were carried out without regional or general anaesthesia. The described treatment concept had a very low complication rate, but required a fairly long hospital stay, with a mean of 32 days (range: 5-82). The long period necessary for completing the treatment in the most complicated cases might render the procedure less attractive as a standard method, but it is nevertheless an excellent option in high-risk patients and in all those patients in whom other procedures are impossible.     

Extracorporeal shock wave lithotripsy with the Storz Modulith SL20: the first 500 patients.

Our initial experience of extracorporeal shock wave lithotripsy (ESWL) with the Storz Modulith SL20 is reported. A total of 500 patients with 551 renal and 120 ureteric stones, mean diameter 11.9 mm, underwent 746 treatments; 68.2% of patients required a single treatment. The mean treatment rate for renal calculi was 1.4 and for ureteric calculi it was 1.5, rising to 4.2 for staghorns; 62.2% of treatments were performed on an out-patient basis. Analgesia (intravenous fentanyl) was required in 60.9% of treatments for renal calculi but in only 38.2% of those for ureteric calculi. The overall stone-free rate at 3 months was 77.6%, with a further 14.7% of patients having fragments less than 3 mm in diameter that required no further treatment. The stone-free rate was dependent on the site of the stone, with the majority of residual fragments lying in a lower pole calix. There were few complications. The Modulith is an efficient and safe lithotripter capable of treating stones in the kidney and throughout the ureter.     

Pediatric shockwave lithotripsy: size matters!

BACKGROUND AND PURPOSE: Shockwave lithotripsy (SWL) is a safe and efficacious modality for pediatric urolithiasis. Recent reports claim good results even with larger stone burdens, irrespective of stone location. We reviewed the outcomes of SWL in the pediatric population at our center to assess the impact of stone burden and location and the age of the child on the stone-free rate. PATIENTS AND METHODS: Records of 106 patients 相似文献   

Percutaneous nephrolithotomy. Experience with renal and proximal ureteral calculi at Tygerberg Hospital

Percutaneous nephrolithotomy (PCN) enables the urologist to remove upper urinary tract stones through a percutaneous nephrostomy tract. The principal advantages of PCN are the low morbidity, shortened hospital stay and rapid recovery. Percutaneous puncture failed in 5 (11%) of the first 44 patients with upper tract urolithiasis treated by PCN at Tygerberg Hospital. In 35 patients (80%) PCN cleared the kidney of stones but in 4 patients (9%) all stone fragments were not removed during the procedure. If the puncture and dilatation was successful, then 90% of patients were stone-free after PCN. Complications were minimal except for a diabetic who died of septicaemia. PCN is an alternative to open renal surgery in the management of most upper urinary tract stones. The technique is readily mastered by any urologist experienced in endoscopic surgery.     

Extracorporeal shock wave lithotripsy treatment in paraplegic patients with bladder stones

BACKGROUND: Spinal cord injury patients are at increased risk of developing urolithiasis and many will require treatment, most commonly with extracorporeal shock wave lithotripsy (ESWL). METHODS: We examined 20 consecutive spinal cord injury patients (all male) undergoing ESWL for the treatment of bladder stones between April 1992 and May 2000. The mean number of shock waves administered in these 20 patients was 3600 and the shock power was 19 kW/s. All patients were treated without anesthesia. After ESWL, the bladder was irrigated with povidone iodine solution and stone fragments were evacuated through a 22F endoscopic sheath. RESULTS: All patients became stone-free after ESWL. Stone fragments were observed in the urethra of 3 patients, which were removed by urethroscopy. No major complication was observed; however, 5 patients had minor hematuria (which subsided within 24 h) and subfebrile fever (37.2-37.5 degrees C). CONCLUSION: ESWL and transurethral bladder irrigation is a safe, effective and simple modality for the treatment of bladder stones in spinal cord injury patients.     

Extracorporeal shock wave lithotripsy in the management of pediatric urolithiasis

The main objective of this paper was to evaluate the efficacy and safety of the management of pediatric urolithiasis by extracorporeal shock wave lithotripsy (ESWL). Between November 1988 and July 2000, 165 renal stones, 53 ureteral stones, and 5 bladder stones were treated in 126 pediatric patients using Siemens Lithostar lithotriptor. The ESWL treatments ranging from 1 to 7 were needed per patient (mean: 2.1). One ESWL session was performed for 49.6% of stones, two for 24.6%, three for 13.0 %, four for 5.6% and > 4 for 8.2%. The success rate for renal stone units (asymptomatic fragments less than 4 mm) was 88.2%, stone-free rate was 49.0%. The stone-free rate for ureteral stone units was 87.5%, but was 75% for bladder stones. The overall results of ESWL treatment in 126 children was satisfactory: the success rate was 90.5%, stone-free rate was 51.6%, residual fragments > 4 mm were 9.5%. General anesthesia was required in 65 children (136 treatments) under the age of 10, and only in 18 children (40 treatments) in the age 11–14. Auxiliary procedures, such as double J stent and percutaneous nephrostomy (PCN) were used in 19 and 7 patients, respectively. Perirenal hematoma in one patient and hematomas in enteric wall in another one patient were the only major complications managed conservatively without consequences. Low energy lithotripsy with the Siemens Lithostar in our series of pediatric patients was safe and relatively effective.     

Extracorporeal shock-wave lithotripsy or ureteroscopy as primary treatment for ureteric stones: a retrospective study comparing two different treatment strategies

OBJECTIVE: Our extracorporeal shock-wave lithotripsy (ESWL) lithotripter with ultrasound localization technique was replaced in 1999 by a Storz SLX-MX lithotripter with both X-ray and ultrasound detection possibilities. Before replacing our lithotripter, most ureteric stones were treated with ureteroscopy (URS); subsequently, almost all patients underwent ESWL as primary treatment. The aim of this retrospective study was to compare the results of these two treatment strategies in all consecutive patients attending our hospital in 1998 and 2000 for ureteric stone treatment. MATERIAL AND METHODS: The medical records of all patients treated for ureteric stones in 1998 and 2000 were reviewed. In 1998, 173 ureteric stones were treated. Primary treatment was URS in 124 patients, push back/ESWL in 24, ESWL in 21 and open surgery in four. In 2000, 176 ureteric stones were treated: 158 with ESWL and 18 with URS. ESWL or URS monotherapy was defined as ESWL or URS, respectively as the only stone-treatment therapy, with or without the use of a ureteric catheter or nephrostomy tube. Treatment success was defined as a stone-free ureter. RESULTS: In 1998, the success rate for URS monotherapy was 95%, with a retreatment rate (sessions per stone situation) of 1.06. Corresponding figures for ESWL monotherapy in 2000 were 90% and 1.69. All URS patients received general anaesthesia; ESWL patients received opiods. Complication rates were 6% for URS and 3% for ESWL. In the URS group, 4/8 complications were considered to be major. CONCLUSION: ESWL should be considered the first-line treatment for ureteric stones because of its non-invasive nature, lack of a requirement for general anaesthesia and low complication rates.     

钬激光腔内治疗泌尿系结石(附126例报告)

目的：探讨泌尿系结石腔内钬激光治疗效果及安全性。方法：总结钬激光结合腔内泌尿外科技术治疗126例泌尿系结石的临床资料。结果：5例肾结石和11例膀胱结石，均一次碎石成功，109例输尿管结石，单次碎石率为96.3%(105/109)，复杂结石1例数次行输尿管腔镜下碎石。平均结石排净时间2.8周，平均手术时间30min，平均术后住院2d。术中除1例输尿管穿孔外，无其他并发症。结论：钬激光结合腔内泌尿外科技术治疗泌尿系结石，是一种较新的、安全的、有效的方法。     

Impact of renal function on efficacy of extracorporeal shockwave lithotripsy

BACKGROUND AND PURPOSE: Adequate urine production and excretion may be important for clearance of stone fragments after extracorporeal shockwave lithotripsy (SWL). This study evaluated the impact of renal function, measured by preoperative serum creatinine concentration, on the efficacy of SWL. PATIENTS AND METHODS: From 1986 to 2001, 27,299 patients with urolithiasis were treated with Medstone STS lithotripters. Seven hundred ninety-eight of these patients (2.92%) had serum creatinine concentrations >or=2.0 mg/dL. Perioperative renal function (serum creatinine), treatment parameters, stone-free success rate (no residual fragments on plain film), and perioperative complications and procedures were recorded. RESULTS: The stone-free rate for patients with serum creatinine values from 2.0 to 2.9 mg/dL (56.69%) was significantly less than that seen in patients with a creatinine concentration <2.0 mg/dL (66.20%). The retreatment rate and secondary-procedure rate were significantly higher in patients with higher serum creatinine values (9.62% and 8.92%, respectively) than in those with serum creatinine within the normal range (6.07% and 4.27%, respectively). There was no significant difference in the stone-free rate, re-treatment rate, and secondary-procedure rate of patients with serum creatinine >or=3.0 mg/dL in comparison with patients with values <2 mg/dL. Complication rates were higher for patients with serum creatinine values >4.0 mg/dL (10.91%) than for patients with creatinine <2.0 mg/dL (2.62%). CONCLUSIONS: The efficacy of SWL is decreased in patients with serum creatinine concentrations of 2.0 to 2.9 mg/dL, and the complication rate is higher in patients with serum creatinine >4.0 mg/dL. Preoperative counseling may include a discussion of the impact of renal insufficiency on success and complication rates associated with SWL.     

Shock wave lithotripsy for uric acid stones

OBJECTIVE: To report our experience of extracorporeal shock wave lithotripsy (SWL) for patients with uric acid stones. METHODS: From December 1987 to December 2003, a total of 443 patients with uric acid stones in the kidney or ureter accepted SWL using ultrasound-guided lithotripters together with alkali therapy. Among them, 168 patients with an average stone burden of 9.1 mm were treated using an EDAP LT-01 piezoelectric lithotripter. The other patients, with an average stone burden of 9.6 mm, were treated using a Dornier Compact S electromagnetic lithotripter. RESULTS: The average duration of treatment using the EDAP LT-01 device was 52.1 minutes with a pulse frequency of 1.25-2.5 shocks per second at 100% power. The average treatment parameters on the Dornier Compact S device were 3,196 shocks at 14.8 kV. For the EDAP LT-01, the 3-month stone-free rate was 86.4%, with a retreatment rate of 24.2%. For the Dornier Compact S, the 3-month stone-free rate was 90.3%, with a retreatment rate of 29.0%. Auxiliary therapy with the push-back technique was needed in 0.45% of patients with upper ureteral stones that could not be localized using ultrasound. The treatment results were best for stones smaller than 20 mm. No anaesthesia was required for any patient. CONCLUSION: SWL with ultrasound localization for uric acid stones is safe and effective. The combination of SWL with urine alkalization may further improve the stone-free rate.