Efficiency Quotient Research Articles

A Prospective Randomized Study Comparing Shock Wave Lithotripsy and Semirigid Ureteroscopy for the Management of Proximal Ureteral Calculi

To conduct a prospective randomized study comparing both techniques for the management of solitary radio-opaque upper ureteral stones < 2 cm in diameter. The ideal treatment for upper ureteral stones > 1 cm size remains to be determined with shock wave lithotripsy (SWL) and ureteroscopy (URS) being acceptable options. A total of 200 patients were included in the study. They were randomized into 2 equal groups. Group A underwent in situ SWL as a primary therapy. Group B underwent URS, using semirigid URS with intracorporeal lithotripsy. Efficiency quotient (EQ), cost analysis, and predictors of failure were estimated for both techniques. For stones of size > or = 1 cm, the initial stone-free rate for URS and SWL was 88% and 60%, respectively. The estimated EQ was 0.79 and 0.43 for both techniques respectively. For stones < 1 cm, the initial stone-free rate for URS and SWL was 100% and 80%, respectively. The estimated EQ was 0.88 and 0.70 for both techniques, respectively. The mean cumulative costs were significantly more in SWL group (P <.05). Predictors of URS failure included; male gender, failure to pass guidewire beyond the stone, and extravasation. Predictors of SWL failure included large stone size > 1 cm, calcium oxalate monohydrate stone, and higher degrees of hydronephrosis. URS with intracorporeal lithotripsy is an acceptable treatment modality for all proximal ureteral calculi, particularly stones > 1 cm. SWL should remain the first-line therapy for proximal ureteral calculi < or = 1 cm because of the less invasive nature and lower anesthesia (i.v. sedation).

Treatment of ureteric lithiasis with retrograde ureteroscopy and holmium:YAG laser lithotripsy vs extracorporeal lithotripsy

To analyse the efficiency of extracorporeal shockwave lithotripsy (ESWL) vs retrograde ureteroscopy and holmium:YAG laser lithotripsy, as ESWL is successful in 67-90% of cases but endoscopic lithotripsy with pneumatic lithotrites or lasers is successful in 90-96% of distal ureteric calculi, and holmium:YAG lithotripsy is effective in proximal ureteric calculi. From April 2006 to April 2008 we assessed 164 patients undergoing ureteric lithiasis in two homogeneous groups: group A included 83 treated with retrograde ureteroscopy and holmium:YAG endoscopic lithotripsy, and group B, 81 treated by ESWL. For laser lithotripsy we used 2071 mJ pulses at 3-6 Hz, with a mean of 1105 pulses and 2.5 kJ of total energy. ESWL was carried out using 37.5-87.5 mJ shock waves, a mean of 3650 shock waves and 187.6 J, with a radioscopy time of 1-4 min. The results were assessed after 3 weeks with plain films and ultrasonography, or urography. The efficiency of each procedure was assessed by calculating the relative risk, and results compared using the chi-square or Student's t-test. The efficiency quotient (EQ) was determined for both procedures, and the focal applied energy quotient (FAEQ) used to assess ESWL. The overall success rate for retrograde ureteroscopy and laser lithotripsy was 96.4% (80/83 patients), with an EQ of 0.52; a JJ catheter was placed in 67 patients. The success rate for the first ESWL session was 48%, and after repeat ESWL was 64% (52/81 patients), giving an EQ of 0.39. For successful treatments the FAEQ was 9.22, vs 6.47 for the failures (P < 0.005). There was a significant difference (P < 0.001) favouring laser lithotripsy, with an absolute benefit of 46% (95% confidence interval 33.8-57.9%), and number needed to treat of 2 (2-3), but no significant differences for lumbar ureteric calculi. Endoscopic lithotripsy with the holmium laser is more effective than ESWL, but for lumbar ureteric calculi ESWL is therapeutically recommended as it is less invasive.

Efficacy of Semirigid Ureteroscopy with Pneumatic Lithotripsy for Ureteral Stone Surface Area of Greater Than 30 mm2

To study the outcome and safety of semirigid ureteroscopy (URS) using pneumatic lithotripsy for treatment of ureteral stones of surface area >30 mm2 and to assess the impact of size and location on stone-free (SF) rate. In this study, 265 patients with >30 mm2 isolated ureteral stones treated by semirigid URS were included. URS was performed using an 8F, 7F, or 6.4F semirigid ureteroscopes with pneumatic lithotripsy (Swiss Lithoclast). Stones were fragmented to approximately 2-3 mm particles, and removed. The outcome parameters assessed at 3-month follow-up were SF rate and efficiency quotient (EQ); impact of stone size and site on SF/EQ was also analyzed. The patient demographics, stone, procedure, and patient-related parameters and complications were noted. At 3-month follow-up overall SF was 74% and EQ 59.2%. SF for 30-100 mm2 and >100 mm2 was 79.2% and 68.5%, respectively (p < 0.003). The SF/EQ for upper, middle, and lower ureteral stones were 59/40.7, 53/37.5, and 92/84.5, respectively (p < 0.001). There was no major complication; the minor complication rate was 12.5%. Semirigid URS using pneumatic lithotripsy for treatment of stones >30 mm2 is a safe and highly efficacious procedure particularly in the distal ureter. There is a significant difference in the SF and EQ between upper/middle ureteral stone and lower ureteral stone. Stone size has a direct relation with the SF and EQ. Upper ureteral stones have a longer time to SF compared to middle and lower ureteral stones (p < 0.001).

DO LITHOTRIPTORS MAINTAIN THEIR EFFECTIVENESS OVER TIME?

This study compared the efficacy and safety profile of electrohydraulic (EH) and electromagnetic (EM) lithotriptors in the treatment of 10- to 20-mm renal and proximal ureteric stones at a single center and by a single operator.Between January 2001 and December 2006, we sequentially treated patients meeting study inclusion criteria with MPL 9000 Dornier EH for the first 3 years, followed by the EM Siemens Modularis shockwave lithotripsy (SWL) unit. A single operator performed all SWL treatments under the supervision of an admitting urologist. We analyzed the demographic features and stone- and treatment-related parameters including complications for both groups. In each group, the stone-free rate and efficiency quotient was determined at 1-3 months.Of 274 patients, we sequentially treated 112 using the EH lithotriptor, and 162 the EM lithotriptor. The pre-SWL patients and stone-related parameters were similar in the two groups, except for diagnostic imaging modalities. The mean number of SWL sessions, need for ancillary procedure, retreatment rate, stone location, stone-free rate, and efficiency quotient were not significantly different between groups. The mean number of shockwaves required for complete fragmentation was 2977 and 6044 (P < .000) for the EH and EM groups, respectively.Single center, single operator experience with two types of lithotriptor indicated that both are equally efficacious, with similar safety profiles. The only significant difference was that the EH lithotriptor required fewer shockwaves for fragmentation.

Does the Type of Lithotripter Affect Outcomes in Children with Upper Tract Urolithiasis?

To compare the treatment outcome and short-term safety of electrohydraulic and electromagnetic lithotripters in children. Comparative analysis of children undergoing shockwave lithotripsy (SWL) with a Dornier MPL 9000 electrohydraulic lithotripter (EHL) and a Siemens Modularis electromagnetic lithotripter (EML) was performed. All SWL treatments were performed by a single operator under the supervision of an admitting urologist. The demographic features, stone, and treatment-related parameters, including complications, were analyzed for both groups. Stone-free (SF) rates, re-treatment rate, and efficiency quotient (EQ) were calculated and compared for the two groups. Ninety-eight children had SWL for renal and proximal ureteral stones. There were 58 children in the EHL group and 40 in the EML group. There were no statistically significant differences between the groups in terms of age, sex, type of anesthesia, diagnostic modality, site, side, and size of the stones. Number of shockwaves used with EML was greater than with EHL (P < 0.00). SF rate was 95% and 77% for EHL and EML, respectively, with a statistically significant difference (P < 0.00). The re-treatment rate was equal in either group. The complication rate was higher with the EHL compared with the EML, although it did not reach statistical significance. Steinstrasse was the most common complication noted. EQ was 66% for the EHL, in comparison with 53% for the EML. The EHL has a better SF and EQ than the EML; however, short-term safety is marginally better with the EML.

A “time-and-motion” study of endoscopic practice: strategies to enhance efficiency

With the growing demand on endoscopic resources, achieving optimal efficiency has assumed increasing importance. This study adopted a time-and-motion approach to assess efficiency in the endoscopy unit of a large teaching hospital and to identify strategies to enhance efficiency. Consecutive endoscopic procedures were prospectively observed over the study period, and time intervals of the individual components of each procedure were recorded. Tertiary-referral teaching hospital. Consecutive patients undergoing endoscopy. Prospective recording of endoscopic data. Time intervals of the individual components of each procedure. Data were prospectively recorded for 400 procedures: 197 EGDs, 123 colonoscopies, 32 flexible sigmoidoscopies, and 48 double procedures (an EGD and a flexible sigmoidoscopy or colonoscopy). Several strategies to improve the efficiency quotient (EQ), the proportion of time that the endoscopist is engaged in performing the procedure or completing postprocedure paperwork, were identified: (1) employing personnel to obtain prior intravenous access and consent of patients increased the EQ by 10.8%, (2) using a 2-rooms-per-endoscopist model increased the EQ by 51.2%, (3) using personnel to both obtain consent and sedate the patient before an endoscopy increased the EQ by 30.9%, and (4) eliminating postprocedure paperwork for the endoscopist in conjunction with preconsent and sedation and a 2-room model increased the EQ by 63.3%. Findings represent the experience of a single endoscopy unit in a tertiary-referral center and may not be generalizable to ambulatory surgical centers or other hospital-based endoscopy units. Factors other than procedure-time components may impact the efficiency of a 2-rooms-per-endoscopist model. A time-and-motion approach can be used to identify strategies to enhance endoscopic efficiency. The quality of any aspect of endoscopy performance should never be compromised in an attempt to enhance efficiency.

Single Center, Single Operator Comparative Study of the Effectiveness of Electrohydraulic and Electromagnetic Lithotripters in the Management of 10- to 20-mm Single Upper Urinary Tract Calculi

This study compared the efficacy and safety profile of electrohydraulic (EH) and electromagnetic (EM) lithotriptors in the treatment of 10- to 20-mm renal and proximal ureteric stones at a single center and by a single operator. Between January 2001 and December 2006, we sequentially treated patients meeting study inclusion criteria with MPL 9000 Dornier EH for the first 3 years, followed by the EM Siemens Modularis shockwave lithotripsy (SWL) unit. A single operator performed all SWL treatments under the supervision of an admitting urologist. We analyzed the demographic features and stone- and treatment-related parameters including complications for both groups. In each group, the stone-free rate and efficiency quotient was determined at 1-3 months. Of 274 patients, we sequentially treated 112 using the EH lithotriptor, and 162 the EM lithotriptor. The pre-SWL patients and stone-related parameters were similar in the two groups, except for diagnostic imaging modalities. The mean number of SWL sessions, need for ancillary procedure, retreatment rate, stone location, stone-free rate, and efficiency quotient were not significantly different between groups. The mean number of shockwaves required for complete fragmentation was 2977 and 6044 (P < .000) for the EH and EM groups, respectively. Single center, single operator experience with two types of lithotriptor indicated that both are equally efficacious, with similar safety profiles. The only significant difference was that the EH lithotriptor required fewer shockwaves for fragmentation.

Generalized theory of thermoelectric figure of merit

The fundamental equations of thermoelectricity are reviewed in a more general and rigorous context and the efficiency quotient of the thermoelements is derived, with emphasis on the relevance of the figure of merit parameter. The Joule–Lenz, thermoelectric and thermoconducted heat are identified, and the ideal situation of a perfectly homogeneous sample subjected to small temperature and voltage gradients is discussed. Thomson heat and the related Peltier effect arising at local inhomogeneities, such as junctions, are also analyzed. In this context, the efficiency quotient is derived for an ideal thermoelectric sample, which reveals a new figure of merit parameter. It is checked explicitly that the efficiency quotient is always lower than the Carnot efficiency quotient, and it is shown that the new figure of merit never exceeds unity.

Measurement Properties of Simple Biomechanical Measures of Walking Effort

A simple measure of overall walking effort would be valuable to patients and clinicians to select suitable treatment interventions and to monitor progress. In this paper, the reproducibility and responsiveness of seven potentially useful clinical measures of walking effort are presented. These walking effort outcomes were derived from a compass gait model and space curve displacement, acceleration and differential geometry theory. The walking effort outcomes were primarily calculated from the motion of a point on or in the rigid body pelvis as a patient walked cyclically. These motion data were collected from eight healthy volunteers who each walked on a treadmill for 4 min, at four different speeds, repeated twice. Four of the seven walking effort outcomes clearly had better measurement properties. The path length ratio, acceleration ratio, Frenet–Serret torsion and Frenet–Serret energy had excellent reproducibility (ICC&gt;0.8) and responded to a small change in walking speed (&lt; 0.03 m/s) compared to two versions of the biomechanical efficiency quotient and the Frenet–Serret curvature. The measurement properties of most outcomes were not consistently improved using a point in versus on the pelvis. This study presents four biomechanical walking effort outcomes that have good theoretical underpinnings, excellent reproducibility and responsiveness, are simple and easy to administer with relatively inexpensive equipment, and can be used in real world environments. However, future work must investigate the minimal clinically important change of these outcome measures before they can be used in clinical practice.

Percutaneous nephrolithotomy outcomes: Re‐audit in 2005

Aim: To evaluate the outcomes of percutaneous nephrolithotomy (PCNL) for upper urinary tract stones in 2005 in our hospital and to compare with the results obtained in 2000.Methods: The present study reviewed the outcomes of standardized PCNL, a one‐stage procedure under sedo‐analgesia, for upper urinary tract stones in 2000 and 2005 in Queen Elizabeth Hospital. In 2000, 74 PCNL were carried out using holmium laser, Swiss lithoclast or electrohydraulic lithotripsy (EHL) for stone fragmentation. Thirty to 40% of staghorn stones and 80–100% of complicated renal and upper ureteric stones achieved stone‐free clearance after single‐session PCNL. In 2005, 82 PCNL were performed after the introduction of three strategies, namely: multiple tract access, flexible nephroscopic exploration and the new‐generation ultrasonic lithotripter. The outcomes were evaluated and compared to those in 2000 according to the different categories of stones.Results: The results in 2005 were improved in terms of increased overall stone‐free rates (20% in single session and 5% after the final session), retreatment rate reduction (15%), and raised efficiency quotient (21.5), while the overall complication rate remained low (13.9%) compared to that in 2000. In 2005, in particular, the single‐session stone‐free rates of staghorn stones and renal pelvis stones were significantly improved to 70–80% (30–40% in 2000) and 100%, respectively (50–60% in 2000). Single‐session stone‐free rates for other stones remained at 90–100%.Conclusion: Our outcomes improvement could be attributed to the maturation of the PCNL technique, use of multiple tract access, use of flexible nephroscopy, and ultrasonic lithotripsy.

Comparison of Percutaneous Nephrolithotomy and Ureteroscopic Lithotripsy in the Management of Impacted, Large, Proximal Ureteral Stones

The optimal treatment for large, impacted, proximal ureteral stones remains controversial. We report our experience and compare treatment outcomes in patients with single, impacted, proximal ureteral stones undergoing percutaneous nephrolithotomy (PCNL) and ureteroscopic lithotripsy (URSL). Between January 2005 and January 2006, a total of 53 consecutive patients with solitary, impacted, proximal ureteral stones > 15 mm in diameter who had undergone PCNL or URSL treatments were enrolled in this study. The mean age was 48.5 +/- 11.8 years. PCNL and URSL were performed in 22 and 31 patients. Stone burdens in the PCNL and URSL groups were 232.8 +/- 113.2 mm2 and 150.3 +/- 70.3 mm2, respectively. The efficiency quotient (EQ) for the PCNL and URSL groups was 0.95 and 0.67, respectively. The stone-free rate at the 1 month follow-up was 95.4% in the PCNL group and 58% in the URSL group (p < 0.001). Two patients in the PCNL group had blood loss requiring transfusion. Eight patients had stones showing upward migration during the URSL procedure, and these stones were subsequently treated by extracorporeal shock wave lithotripsy and PCNL. For an impacted, proximal ureteral stone > 15 mm in diameter, PCNL had better stone-free rates and could simultaneously treat coexisting renal stones. However, URSL had the advantages of shorter operative times, shorter postoperative hospital stays, and fewer postoperative complications.

Stone Treatment Index: A Mathematical Summary of the Procedure for Removal of Stones from the Urinary Tract

Numerous factors influence the treatment result and efforts for stone removal. To summarize the important factors, our aim was to formulate a general mathematical expression of the stone-removal procedure. A mathematical expression (stone treatment index; STI) was developed for patients who became stone free (SF): STI(SF) = (Num(SF) x mean(sqrt [SA] x HI) x meanAge(R) x meanBMI(R) x (1 + meanNum(ANA)) divided by Num(SESSIONS) + Num(AUX) + Num(ANE) + Num(COMP). The variables included were the number of stone-free patients (Num(SF)), mean stone burden expressed as the product of the square root of the stone surface area (SA(1/2)) and the hardness index (HI), the mean age ratio (Age(R) = age/50), the mean body mass index (BMI) ratio (BMI(R) = BMI/25), the mean number of patients with anatomic abnormalities (Num(ANA)), the total number of treatment sessions (Num(SESSIONS)), the number of auxiliary procedures (Num(AUX)), the number of procedures requiring general or regional anesthesia (Num(ANE)), and the number of complications (Num(COMP)). A similar index was calculated for patients who were either stone free or had residual fragments < or =4 mm (STI(DIS)). For conclusions on efficacy, these indices were compared with optimal and total values of STI. The STI was calculated for 450 patients with renal and 374 patients with ureteral stones treated with shockwave lithotripsy as the primary procedure. In patients with a known BMI, this factor was used; otherwise, the BMI(R) was set to 1. When STI was compared with the efficiency quotient (EQ) for stones in different size intervals, STI was less sensitive to variations in stone burden. The quotients STI(SF)/STI(OPTIMAL) corresponded roughly to EQ but might be more informative because of the inclusion of factors for anesthesia and complications. With or without related estimates, the STI might be useful for summarizing stone-removal procedures in groups or individual patients with urinary-tract stones. The STI might be helpful because it encompasses the factors of importance for conclusions about the treatment procedure, such as the hardness of the stone, the age and body size of the patient, and the presence of anatomic abnormalities likely to influence the result. The STI might be used advantageously for comparison of different equipment and treatment strategies.

Outcomes using a fourth-generation lithotripter: a new benchmark for comparison?

To evaluate the efficacy of a fourth-generation lithotripter, the Sonolith Vision (Technomed Medical Systems, Vaulx-en-Velin, France) for treating single previously untreated renal calculi, and to compare the results with the reference standard HM-3 (Dornier MedTech Europe GmbH, Wessling, Germany) in the same population originally studied by the USA Cooperative Study Group in 1986. The Sonolith Vision uses an innovative electroconductive shock-wave generator with an elliptical reflector specially designed to give the maximum concentration of energy on the stone. We reviewed the treatment sessions from our prospectively maintained database of the first 1000 consecutive patients with urinary stone disease who were treated with the Sonolith Vision between September 2004 and March 2006. Patients with previously untreated solitary renal calculi in anatomically normal kidneys were included. The outcome was assessed by plain films for radio-opaque stones, and renal ultrasonography for radiolucent stones, at 1 and 3 months after lithotripsy; the results were analysed according to stone size and location. Data from 309 patients who had a complete follow-up and with 373 renal calculi that matched the above criteria were analysed. The initial fragmentation rate was 94%. The stone-free rate for stones of <10 mm was 77%, for 11-20 mm was 69% and for >20 mm was 50%. The overall stone-free rate 3 months after lithotripsy was 75%. Within a month of lithotripsy, 221 patients (59%) became stone-free. Additional procedures to render patients stone-free after lithotripsy were needed in only 22 cases (7%). The overall efficiency quotient was 62%. The stone-free rates for lower, upper, middle calyceal and renal pelvic calculi were 74%, 70%, 78.5% and 75%, respectively. There were no serious complications. When similar populations of stone formers were assessed the Sonolith Vision achieved a high success rate, comparable with that using the HM-3 machine but with lower analgesia requirements and very low re-treatment rates. This method of comparison belies the commonly held view that newer lithotripters are less effective than the original spark-gap machines.

Comparative Results of Shockwave Lithotripsy for Renal Calculi in Upper, Middle, and Lower Calices

To assess the results of shockwave lithotripsy (SWL) for renal calculi in upper, middle, and lower calices according to the stone burden. A series of 52 female and 66 male patients with a mean age of 47.8 years and isolated single caliceal stones who underwent SWL monotherapy were enrolled. Stone burden, stone location, number of sessions/shockwaves, and auxiliary procedures were noted for each patient. Stones were located in the upper, middle, and lower calices of 35, 43, and 40, patients respectively, with mean stone burdens of 81.4 mm2, 75.2 mm2, and 96.3 mm2, respectively. Patients were evaluated with intravenous urography, plain film, or ultrasonography. Success was determined 3 months after the last session. Re-treatment rates were calculated. The effect of anatomic factors on the success of treatment for lower-caliceal stones also was determined. The mean stone burden, median number of treatment sessions, and mean number of shockwaves were 84.2 mm2, 2, and 4344, respectively. The auxiliary procedure rate was 16.1%, and the re-treatment rate was 71.2%. Failure was noted in 26 patients (22%). The stone-free rates for stones in the upper, middle, and lower calices were 82.8%, 83.4%, and 67.5%, respectively (P = 0.14). The stone-free rates for stones <100 mm2 and 100 to 200 mm2 were 91.2% and 65.5%, respectively (P = 0.001). The efficiency quotient was 49.8, 44.8, and 32.5 for upper-, middle-, and lower-caliceal stones, respectively. Infundibular length (P = 0.006) and infundibular width (P + 0.036) were significant in determining the stone-free rate after treatment of lower-caliceal stones. We recommend SWL as the first choice for treatment of stones <200 mm2 in the upper and middle calices. Extracorporeal lithotripsy is one of the options for lower-caliceal stones <200 mm2 but has high re-treatment and auxiliary-procedure rates in these cases.

Critical Prospective Appraisal of Renal Morphology and Function in Children Undergoing Shockwave Lithotripsy and Percutaneous Nephrolithotomy

To assess the effect of shockwave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL) on renal morphology and function in children undergoing therapy for upper-tract urolithiasis. Fourteen patients less than 13 years of age with renal or upper-ureteral calculi who were found suitable for primary SWL or PCNL were evaluated for alteration of renal morphology and function after treatment. Of the 18 renal units treated, SWL and PCNL were performed in 9 units each. The average stone size was 880.2 mm2 (range 110-3800 mm2; median 660 mm2). All children underwent ultrasonic estimation of renal length and parenchymal thickness, 99m technetium dimercaptosuccinic acid (DMSA) and 99m Tc-ethylene dicystine (EDC) scintigraphy, and glomerular filtration rate (GFR) estimation prior to intervention and at 3 and 6 months of follow-up. Extracorporeal lithotripsy achieved complete clearance in 8 renal units (88%), requiring an average of 6333 shockwaves and an average of 2.2 sessions per renal unit. The efficiency quotient was 42. Percutaneous surgery likewise achieved complete stone clearance in 88% of renal units, with three units requiring more than one tract. Mixed calcium oxalate monohydrate and dihydrate accounted for the majority of the stones. The mean preintervention GFR was 78.3 +/- 14.6 mL/min/1.73 m2 (median 82.5 mL/min/1.73 m2; range 54-98.6 mL/min/1.73 m2), whereas the mean GFR at 3 months was 78.95 +/- 14.4 mL/min/1.73 m2 (median 78.95 mL/min/1.73 m2; range 52-98 mL/min/1.73 m2). A marginal improvement of an average of 0.65 mL/min was noted. Split function EDC scans demonstrated improved drainage in five cases after intervention; the rest were unchanged. Preintervention DMSA scans revealed renal cortical scars in three children. None of the renal units had developed fresh scars at follow-up scans. None of the children developed new-onset hypertension, proteinuria, or alteration in renal size. In the present study, pediatric SWL and PCNL were not found to cause adverse renal morphologic or functional alteration. Stone clearance resulted in marginally improved function and better drainage.

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

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. 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. 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%. 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.

Comparison of Three Analgesic Regimens for Pain Control during Shockwave Lithotripsy Using Dornier Delta Compact Lithotripter: A Randomized Clinical Trial

To compare the efficacy and adverse effects of oral diclofenac, topical eutectic mixture of local anesthesia (EMLA), and their combination for pain control during shockwave lithotripsy (SWL) and to investigate the need for supplemental analgesia, patient satisfaction, and overall treatment outcomes. A series of 240 consecutive patients with urolithiasis scheduled for SWL between May 2006 and December 2006 were randomized equally into three groups that were treated as follows: group A oral (tablet) diclofenac sodium 60 minutes prior to SWL (50 mg for body weight <70 kg; 100 mg for body weight >70 kg); group B occlusive dressing of EMLA (5 g) 60 minutes prior to SWL; group C combination of oral diclofenac sodium (in the prescribed dose) and occlusive dressing of EMLA (5 g) 60 minutes prior to SWL. A visual analog scale (VAS) was used for the subjective evaluation of pain. The various parameters were recorded and analyzed statistically. The total number of shock waves delivered, the maximum voltage used, and SWL duration were statistically greater in group C (P < 0.0001). The VAS scores at 15, 30, 45, 60, and 120 minutes and the supplemental analgesia requirement were statistically less in group C (P < 0.0001). The stone fragmentation rate, stone-free rate at 3 months (88.75%), and modified Efficiency Quotient (0.64) were statistically greater in group C (P < 0.0001). The post-SWL auxiliary procedure rate (P < 0.0001) and Steinstrasse rate (P = 0.03) were statistically less in group C. The use of a combination of oral diclofenac sodium and an occlusive dressing of EMLA cream during SWL provides adequate analgesia with minimal morbidity, avoids the need for parenteral analgesics and their attendant side effects, and improves the success rate of SWL.

The Medstone Fixed, Mobile, and Modular Configurations: Impact on Efficacy

To evaluate the efficacy of three lithotripter configurations that utilize the Medstone STS treatment head. 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. 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). 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.

Pediatric Shockwave Lithotripsy: Size Matters!

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. Records of 106 patients <or=16 years of age (mean age 10.9 years) treated with SWL for stones with a surface area of 20 to 600 mm2 (mean 124.17 mm2) from July 1989 to June 2004 were reviewed. Metabolic abnormalities were present in 20.7% of the patients. All procedures were performed using the Siemens Lithostar, and stone clearance was assessed 3 months after SWL. Complications and the need for re-treatment and ancillary procedures were noted, and the impacts of stone size and location and the age of the child on stone clearance were assessed. The overall stone-free rate was 87% (complete clearance 72%; insignificant [<3-mm] residual fragments 15%). The re-treatment rate was 58%, and the efficiency quotient was 47. Whereas stone size correlated strongly with the stone-free rate (Mann-Whitney U test x = 0.004; chi-square test P = 0.02), patient age and stone location did not have a significant impact. Extracorporeal shockwave lithotripsy is an effective modality to treat pediatric upper urinary-tract calculi, especially when the stone burden is <200 mm2. Larger stone burdens are associated with poorer results, necessitate more ancillary procedures, and have a higher complication rate.

Impact of Shockwave Coupling on Efficacy of Extracorporeal Shockwave Lithotripsy

To evaluate the impact of a slow gated treatment rate on the efficacy of extracorporeal shockwave lithotripsy (SWL). 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. 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. 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.