The effectiveness of shock wave lithotripters: a case matched comparison.

PURPOSE: We compared the results of shock wave lithotripsy with a newer electromagnetic lithotripter to those of an electrohydraulic lithotripter using identical treatment and followup criteria. MATERIALS AND METHODS: We performed a case matched comparison of 8,565 patients treated from 2003 to 2007 using the Medstone STS™ and the Modulith® SLX machines, matching for stone size, location and patient body mass index. The outcome of interest was treatment success in producing stone-free status. We report treatment characteristics, such as stone site and size, gating and final stone-free rate. Significance was considered at p<0.05. RESULTS: Overall Modulith SLX and Medstone STS stone-free rates were equivalent (61.1% and 64.5%, respectively, p=0.0664). Matching and logistic regression results showed that differences in the stone-free rate were insignificant for all stones (p>0.7592), lower pole kidney stones (p=0.9659) and ureteral stones (p=0.6409). Medstone STS performed better than Modulith SLX only for distal ureteral stones (83.63% vs 66.67%, p=0.0154). The rate of post-lithotripsy secondary procedures was equivalent (p=0.2079). The difference was insignificant for harder stones (p=0.2988). CONCLUSIONS: Shock wave lithotripsy is equally effective using Medstone STS and Modulith SLX for different stone sizes and most stone sites. Shock wave lithotripsy is more successful for lower ureteral stones using the Medstone STS. To our knowledge this is the first study comparing these 2 commonly used lithotripters.

Stone size is only independent predictor of shock wave lithotripsy success in children: a community experience.

PURPOSE: We determined whether age, gender, body mass index, number of stones, stone location or total stone diameter could independently predict stone-free rates after extracorporeal shock wave lithotripsy in children. MATERIALS AND METHODS: We reviewed 149 patients 3 to 17 years old undergoing shock wave lithotripsy between 2001 and 2008. Cases were retrieved from a regional shock wave lithotripsy database. Variables analyzed included age, gender, body mass index, number of shocks delivered, stone location, number of stones and total stone diameter. Stone-free status on followup imaging at 2 weeks to 3 months was considered a successful outcome. RESULTS: Of 149 patients 32 had multiple stones. After shock wave lithotripsy 106 patients (71%) were stone-free, 12 (8%) required a repeat procedure and 31 (21%) had residual fragments. Number of stones per patient ranged from 1 to 18 (mean +/- SD 2.14 +/- 2.60). Mean +/- SD number of stones was 1.87 +/- 2.42 in successfully treated patients and 2.81 +/- 2.92 in those with treatment failure (p = 0.065). Total stone diameter ranged from 2 to 90 mm (mean +/- SD 14.03 +/- 16.68). Mean total stone diameter was 11.1 +/- 13.4 mm in successfully treated patients and 21.3 +/- 21.4 mm in those with treatment failure (p <0.005). CONCLUSIONS: To our knowledge we present the first multi-institutional cohort study in children demonstrating no significant relationship between successful outcome and patient age, gender, body mass index, stone location or number of stones. Only total stone diameter independently predicted shock wave lithotripsy success.

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.

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.

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 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.

Shock wave lithotripsy associated with greater prevalence of hypertension.

OBJECTIVES: To determine whether shock wave lithotripsy (SWL) increases the prevalence of hypertension (HTN) at intermediate follow-up. METHODS: All patients were treated with the Medstone STS electrohydraulic lithotripter, and the data were recorded prospectively in a centralized database. The data on the development of HTN after SWL was obtained from a questionnaire mailed to the patients who had undergone SWL from November 1999 and January 2002. Controls matched for age, sex, and body mass index were obtained from the National Health and Nutrition Examination Survey, using the demographic, body measurements, medical conditions, and blood pressure data sets. Two sets of matching controls were used to compare the prevalence of HTN between our patients and the NHANES population at SWL and at the follow-up point. RESULTS: A total of 2041 patients responded to the questionnaire, with a median follow-up of 6 years. No statistically significant difference was found in the HTN prevalence between the patients and matched controls at SWL (26.7% vs 28.0%). At the follow-up point, the prevalence of HTN was greater in our patients (37.8%) than in the controls (32.5%, P=.0009). Of our patients, 15% have developed de novo HTN compared with the predicted rate of 6.25% from the matched controls. Male gender, age, and a greater body mass index were associated with the development of HTN, but none of the SWL parameters (number of shocks, bilateral vs unilateral, and multiple SWL sessions) were significantly associated with HTN. CONCLUSIONS: The results of our study have indicated a small, but significant, increase in the risk of developing HTN after SWL using a third-generation electrohydraulic lithotripter at intermediate follow-up.

Shock wave lithotripsy not associated with development of diabetes mellitus at 6 years of follow-up.

OBJECTIVES: To investigate the hypothesis that extracorporeal shock wave lithotripsy (ESWL) increases the incident risk of new-onset diabetes mellitus (DM). Studies have suggested that ESWL predisposes to DM. METHODS: Using a mail survey, we collected data on the presence and onset of DM in 1947 patients treated with the Medstone-STS electrohydraulic lithotripter from 1999 to 2002. These patients were matched by age, sex, and body mass index to controls from the National Health and Nutrition Examination Survey (NHANES) database. Of the 1947 patients, 4% could not be matched and were excluded, leaving 1869 for analysis, of whom 60.0% were men. The mean age was 51.9 years at ESWL and the median follow-up was 6 years. The mean body mass index at the end of the study was 28.6 kg/m(2). RESULTS: At ESWL, 8.67% of matched patients had a diagnosis of DM. This had increased to 13.9% at the time of survey. In the NHANES group, 8.34% had DM at the time the ESWL group underwent treatment, and this had increased to 14.1% at the NHANES survey. Therefore, the rate of new DM cases in the ESWL group was similar to that in the NHANES group (5.2% vs 5.8%, respectively; P = .47). Multivariate analysis of the patient cohort confirmed that age, sex, body mass index, and family history correlated with development of DM and that the laterality of treatment and number of treatments or shocks given were not significant predictors of DM. CONCLUSIONS: The results of our study have shown that patients treated with ESWL do not develop DM at a greater rate than does the general population at 6 years of follow-up.

Impact of learning curve on efficacy of shock wave lithotripsy.

INTRODUCTION: The purpose of this study was to evaluate the impact of a radiographer's learning curve on extracorporeal shock wave lithotripsy (SWL) efficacy. METHODS: Five registered technologists who were certified to assist in SWL procedures but had no prior lithotripter experience were evaluated during a 4-year period. Stone-free (no residual fragments on plain radiographic imaging), re-treatment and post-SWL procedure rates were evaluated for the first 3 years of radiographer employment. RESULTS: The overall stone-free rate increased from 55% (efficiency quotient [EQ] 45) in the first year to 68% (EQ 50) in the third year. The treatment success rate for the lower calyx increased from 50% (EQ 41) in the first year to 62% (EQ 44) in the third year. There was no difference in re-treatment or post-SWL procedure rates. CONCLUSION: Efficacy with SWL, as measured by stone-free rates, improved with increasing experience of the radiographer. Ongoing supervision and mentorship might be helpful in the first year of service.

Eighteen-year experience with the Medstone STS lithotripter: safety, efficacy, and evolving practice patterns.

OBJECTIVE: To evaluate trends in safety, efficacy, and practice patterns for shockwave lithotripsy (SWL) procedures performed during a 18-year period and correlate the findings with recent evidence-based practice guidelines. MATERIALS AND METHODS: From January 1988 to June 2006, 66,819 SWLs were performed using the Medstone STS lithotripter in patients with radiologic evidence of stones in the kidney or ureter. Treatment characteristics, such as stone location and size, need of re-treatment, and final success rate were recorded. The procedures were further divided by year for statistical consideration. Statistical analysis was performed using Student t test; P < 0.05 was considered significant. RESULTS: Overall SWL success rate was 85% (39,667/46,669), and the overall re-treatment rate was 7.2% (3,417/46,669). There was no significant change in the overall proportion of lower-pole calculi managed with SWL, although there was a significant decrease in the proportion of SWL used for lower calix stones larger than 16 mm in the time period after 2000 (P = 0.006). There was a steady increase in the number of procedures performed for renal calculi in other locations per year, in particular for intrarenal calculi smaller than 20 mm. Intrarenal stones larger than 30 mm decreased as a proportion of procedures per year (P = 0.048) There was no significant change in the proportion of upper and distal ureteral stones managed, corresponding to a solid plateau in the percentage of SWL performed per year. CONCLUSION: Our study did not demonstrate an overall drop in SWL; however, it did show the interference of endoscopic procedures on two case scenarios. There was a significant decrease (P = 0.048) in SWL for renal stones larger than 30 mm, and the same trend was noted for lower calix stones larger than 15 mm (P = 0.06).

A pilot study on the early use of the vacuum erection device after radical retropubic prostatectomy.

OBJECTIVE: To evaluate the effect of the early use of the vacuum erection device (VED) on erectile dysfunction (ED) and penile shortening after radical retropubic prostatectomy (RP), as these are important concerns for men choosing among treatment alternatives for localized prostate cancer. PATIENTS AND METHODS: Twenty-eight men undergoing RP were randomized to early intervention (1 month after RP, group 1) or a control group (6 months after RP, group 2) using a traditional VED protocol. An International Index of Erectile Function (IIEF) score of >11 (no, mild or mild to moderate ED) was required as a baseline criterion for inclusion in the study. Only patients in whom unilateral or bilateral nerves were spared were subsequently randomized. Patients in group 1 followed a daily rehabilitation protocol consisting of 10 min/day using the VED with no constriction ring, for 5 months. Patients were evaluated with the IIEF-5 questionnaire and measurements of penile flaccid length, stretched length, prepubic fat pad, and midshaft circumference before and at 1, 3, 6, 9 and 12 months after RP; the mean (range) last follow-up visit was 9.5 (6-12) months after RP. RESULTS: The mean (sd) baseline IIEF scores were similar in groups 1 and 2, at 21.1 (4.6) and 22.3 (3.3), respectively (P = 0.54). The IIEF scores were significantly higher in group 1 than group 2 at 3 months, at 11.5 (9.4) vs 1.8 (1.4) (P = 0.008) and at 6 months, at 12.4 (8.7) vs 3.0 (1.9) (P = 0.012) after RP. There were no significant changes in penile flaccid length, prepubic fat pad, or mid-shaft circumference in either group. Stretched penile length was significantly decreased at both 3 and 6 months, by approximately 2 cm (P = 0.013) in group 2. By contrast, stretched penile length was preserved in group 1 at all sample times. At the last follow-up, the proportion of men with a mean loss of penile length of >/= 2 cm was significantly lower in group 1 than group 2 (two/17, 12%, vs five/11, P = 0.044). CONCLUSIONS: Initiating the use of a VED protocol at 1 month after RP improves early sexual function and helps to preserve penile length.

Long-term pooled analysis of multicenter studies of cooled thermotherapy for benign prostatic hyperplasia results at three months through four years.

OBJECTIVES: To determine the long-term efficacy of cooled thermotherapy in the treatment of lower urinary tract symptoms of clinical benign prostatic hyperplasia. METHODS: A total of 541 men underwent cooled thermotherapy treatment in six multicenter studies in the United States, England, and Canada. Both fixed and random effects models were used to pool the data across the six studies. The treatment response was measured as the difference between the urinary tract symptoms at baseline versus those at 3, 12, 24, 36, and 48 months after therapy. The treatment response included changes in the American Urological Association Symptom Score (AUA symptom score), peak urinary flow rate in milliliters per second (Qmax), and quality of life (QOL). RESULTS: The baseline measures were comparable across the studies. At 3 months, the AUA symptom score had improved by a mean of 11.6 (55%), Qmax by a mean of 4.0 (51%), and QOL by a mean of 2.3 (53%). These changes persisted with only slight attenuation through 48 months (corresponding mean changes of 43%, 35%, and 50%). These changes were highly statistically significant (P <0.0001 to 0.01). An improvement of at least 25% was achieved for the AUA symptom score and QOL by more than 85% of men and by more than 65% of men for Qmax. CONCLUSIONS: This pooled analysis of six multicenter studies of cooled thermotherapy, involving 541 men, found highly significant improvements in AUA symptom score, Qmax, and QOL. The results were highly consistent across the studies. The improvements reflected changes from baseline values of 45% to 50% for AUA symptom score and QOL and 35% to 40% for Qmax at a follow-up duration up to 48 months after therapy. The level of improvement for all three measures remained high at 48 months, indicating that the response is durable.

Treatment of organ confined prostate cancer with third generation cryosurgery: preliminary multicenter experience.

PURPOSE: Cryosurgical ablation of the prostate is 1 approach to the treatment of localized prostate cancer. Third generation cryosurgery uses gas driven probes that allow for a decrease in probe diameter to 17 gauge (1.5 mm). The safety, morbidity and preliminary prostate specific antigen (PSA) results of 122 cases are reported. MATERIALS AND METHODS: A total of 106 patients have undergone percutaneous cryosurgery using a brachytherapy template with at least 12 months of PSA followup. Immediate and delayed morbidities were evaluated. PSA results at 3 and 12 months were recorded, and failure was defined as the inability to reach a nadir of 0.4 ng/ml or less. RESULTS: Complications in patients undergoing primary cryosurgery included tissue sloughing (5%), incontinence (pads, 3%), urge incontinence/no pads (5%), transient urinary retention (3.3%) and rectal discomfort (2.6%). There were no cases of fistulas or infections. Postoperative impotence was 87% in previously potent patients. For patients who underwent salvage cryosurgery there were no fistulas reported and 2 (11%) patients required pads after salvage cryosurgery. A total of 96 (81%) patients achieved a PSA nadir of 0.4 ng/ml or less at 3 months of followup, while 79 of 106 (75%) remained free from biochemical recurrence at 12 months. A total of 42 (78%) low risk patients (Gleason score 7 or less and PSA 10 or less) remained with a PSA of 0.4 ng/ml or less at 12 months of followup, compared to 37 (71%) high risk patients. All patients were discharged within 24 hours. CONCLUSIONS: After a followup of 1 year 3rd generation cryosurgery appears to be well tolerated and minimally invasive. The use of ultrathin needles through a brachytherapy template allows for a simple percutaneous procedure and a relatively short learning curve. A prospective multicenter trial is ongoing to determine the long-term efficacy of this technique.