In situ echoguided extracorporeal shock wave lithotripsy of ureteric stones with the Dornier MPL 9000: a multicentric study group

Role of clinical and radiological parameters in predicting the outcome of shockwave lithotripsy for ureteric stones

Introduction:

Shockwave-lithotripsy (SWL) provides a noninvasive and effective option for the management of ureteric calculi. Several factors may affect the success of SWL. Identification of these predictive factors will both increase the efficacy and decrease the cost. This study was designed to identify factors affecting the outcome of SWL for ureteral stones.

Materials and Methods:

This study was conducted from March 2012 to November 2014 in patients with solitary ureteric calculi who were managed with SWL. Data were analyzed to identify clinical and radiological factors associated with treatment outcome. Success after SWL was described as complete stone clearance or clinically insignificant residual fragments <3 mm at 3 months after SWL.

Results:

A total of 110 patients with ureteric calculi were divided into two groups depending on the outcome of SWL, Group A (successful - 76%) and Group B (failed - 24%). Stone size, Skin to stone distance (SSD), secondary signs of obstruction, and presence of double J (DJ) Stent, all were significantly associated with the outcome of SWL on univariate analysis. On multivariate analysis, stone size, hounsfield unit, SSD, and DJ stent were the independent factors affecting the outcome of SWL. On Receptor-Operator Characteristic curve analysis, a cutoff value of 8.2 mm for the stone size was found which best predicts a successful outcome, with a sensitivity of 54% and specificity of 96%.

Conclusion:

The findings of this study suggest that Stone size, SSD, the presence of DJ stent, and stone attenuation values are the significant factors that influence the outcome of SWL in patients with ureteral stones.

Impact of Pretreatment Hydronephrosis on the Success Rate of Shock Wave Lithotripsy in Patients with Ureteral Stone

PURPOSE

To evaluate predictors of the success rate for one session of shock wave lithotripsy (SWL), focusing on the relationships between pretreatment hydronephrosis grade and one-session SWL success rates.

MATERIALS AND METHODS

The medical records of 1824 consecutive patients who underwent an initial session of SWL for treatment of urinary stones between 2005 and 2013 were reviewed. After exclusion, 700 patients with a single, 4-20 mm diameter radiopaque calculus were included in the study.

RESULTS

The mean maximal stone length (MSL) and skin-to-stone distance were 9.2±3.9 and 110.8±18.9 mm, respectively. The average values for mean stone density (MSD) and stone heterogeneity index (SHI) were 707.0±272.1 and 244.9±110.1, respectively. One-session success rates were 68.4, 75.0, 75.1, 54.0, and 10.5% in patients with hydronephrosis grade 0, 1, 2, 3, and 4, respectively. Patients were classified into success or failure groups based on SWL outcome. Multivariate logistic regression analyses revealed that MSL [odds ratio (OR) 0.888, 95% confidence intervals (CI): 0.841-0.934, p<0.001], MSD (OR 0.996, 95% CI: 0.995-0.997, p<0.001), SHI (OR 1.007, 95% CI: 1.005-1.010, p<0.001), and pretreatment hydronephrosis grade (OR 0.601, 95% CI: 0.368-0.988, p=0.043) were significantly associated with one-session success.

CONCLUSION

Pretreatment grades 3 or 4 hydronephrosis were associated with failure of SWL in patients with a single ureteral stone. In the presence of severe hydronephrosis, especially hydronephrosis grade 4; physicians should proceed cautiously in choosing and offering SWL as the primary treatment for ureteral stone.

Semirigid ureteroscopy in management of large proximal ureteral calculi: is there still a role in developing countries?

OBJECTIVES

To evaluate the outcome and complications of the use of semirigid ureteroscopy (URS) together with intracorporeal pneumatic lithotripsy in the management of upper ureteral calculi >10 mm in diameter.

METHODS

A total of 75 patients (41 women and 34 men), with a mean age of 48 years (range 25-60), underwent primary URS for solitary radiopaque proximal ureteral calculi 10-20 mm in diameter (average 13.1). Dilation of the intramural ureter was done in 60 cases (80% of patients), and intracorporeal lithotripsy was required in 56 (74.6%). Ureteral catheters were left for drainage in 60% of patients, 26.7% were left unstented, and only 13.3% required an indwelling stent.

RESULTS

Of the 75 stones, 60 (80%) were successfully cleared after a single endoscopic procedure. Our initial stone-free rate was 90.6% at 2 weeks after the primary endoscopic procedure and had reached 98.6% at 3 months. Antegrade URS for migrating stones was done successfully in 6 cases in a tubeless fashion, and open ureterolithotomy was required in 1 case. No major complications were encountered. The minor complications included only mild extravasation and self-limited postoperative fever and hematuria. The risk factors for URS failure included male gender, the severity of the hydronephrosis, the severity of impaction, and the occurrence of extravasation.

CONCLUSIONS

The results of our study have shown that semirigid URS is a safe and successful alternative to open ureterolithotomy in the management of large proximal ureteral calculi in the absence of flexible instruments.

Comparative study of extracorporeal shock wave lithotripsy outcomes for proximal and distal ureteric stones

OBJECTIVE

To assess the efficacy of extracorporeal shock wave lithotripsy (ESWL) monotherapy for isolated proximal ureteral calculi and compare it to that for isolated distal calculi.

PATIENT AND METHODS

We treated 68 patients with isolated ureteral stones using MPL 9000. Stones were located in the proximal and distal ureters in 44 and 24 patients, respectively. Patients were stratified according to stone burden and degree of obstruction. Data of all patients were prospectively collected for stone burden, stone localization, number of sessions, number of shock waves, stone-free rates (SFRs), complications, re-treatment rates and auxiliary procedures. Outcomes regarding ureteral localization were compared.

RESULTS

The overall SFR was 85.3% with a 41.2% re-treatment and 17.6% auxiliary procedure rate. The mean number of shock waves applied for each stone was not different among the two ureteral locations. The SFRs were 86.3% and 79.1% for proximal and distal ureteral stones, respectively (P=0.17). For the group with stones <100 mm(2), the SFR was 85.4% and 89.5% for the proximal and distal ureter, respectively. Although the degree of obstruction did not affect SFR of the entire group (P=0.12) and the proximal ureter group (P=0.96), it adversely affected SFR in the distal ureter (P=0.017).

CONCLUSIONS

ESWL outcomes for the ureteral calculi support the use of lithotripsy particularly for stones <100 mm(2). Treatment efficacy was not significantly different among stones localized in proximal and distal ureters. Degree of obstruction did not affect the ESWL outcomes in the proximal ureter, but it adversely affected SFR in the distal ureter.

When is open ureterolithotomy indicated for the treatment of ureteral stones?

AIM

Improvements in extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy have almost eradicated the need for open surgery in ureteral stones. The aim of this study was to assess characteristics of patients who underwent open ureterolithotomy.

METHODS

During a 5-year period, a total of 654 patients with ureteral stones were treated. Initial management consisted of ureteroscopy in 524 patients, ESWL in 62 patients and percutaneous nephrolithotomy (PCNL) in 12 patients. Open surgery was performed in 56 patients. Stone location, size and success rates were retrospectively analyzed.

RESULTS

Ureteroscopy resulted in successful stone removal in 94%, 98% and 98.5% of proximal, mid and distal ureteral stones, respectively. A total of 14 patients with ureteroscopy failure were referred for open surgery. ESWL treatment resulted in success in 55 patients (88%), and those with ESWL failure were referred for either ureteroscopy (n = 3) or open surgery (n = 4). Open surgery was performed in a total of 56 patients, 38 of whom had been referred from other centers. Stone location was proximal ureter in 25 (44.6%) patients (stone size: 2-12 cm(2)), mid ureter in five (8.9%) patients (stone size: 2-6 cm(2)) and distal ureter in 26 (46.4%) patients (stone size: 4-9 cm(2)). A history of previous unsuccessful endourological procedure was observed in 33 (58%) of 56 patients. Children under age 16 (range 1-15 years) comprised 17.8% of patients undergoing open surgery.

CONCLUSION

Open surgery, which is nowadays being replaced with laparoscopic techniques, is generally indicated for failed endourological procedures (58%), particularly in centers that do not have flexible ureteroscopy or laser lithotriptor, and in patients with larger stones (>3 cm). Children (17.8%) are also candidates for open surgery, if specifically designed endourological equipment is not available.

Efficacy of Extracorporeal Shockwave Lithotripsy with Patients Rotated Supine or Rotated Prone for Treating Ureteral Stones: A Case-Control Study

PURPOSE

To improve the therapeutic efficacy of extracorporeal shockwave lithotripsy (SWL) for ureteral stones by attempting semilateral/rotated approaches. There has been no study that shows the advantage of rotated positions.

PATIENTS AND METHODS

Two hundred forty-eight (group 1) and 156 (group 1R) patients with proximal-ureteral stones were treated by the Dornier Lithotriptor U15/50 in the supine and rotated-supine position, respectively. When residual calculi remained in the middle-distal ureter, group 1 subjects underwent subsequent sessions in the ordinary prone position, and Group 1R patients were treated in the rotated-prone position. Sixty-two (group 2) and 60 (group 2R) patients with primary middle-ureteral stones were treated in the prone and rotated- prone position, respectively, while 110 (group 3) and 98 (group 3R) patients with distal-ureteral stones were treated in the prone and rotated-prone position, respectively.

RESULTS

Although the stone-free rate was not different in group 1 (94.8%) and 1R (97.4%), the number of sessions required for Group 1R patients to be stonefree (mean 1.49) was less than for Group 1 patients (mean 1.74; p=0.023). Group 1R patients tolerated a higher shockwave intensity than group 1 patients for sessions in the proximal ureter (p=0.042). The stone-free rate for Groups 1 and 1R for booster sessions in the middle- distal ureter was 85.4% and 100%, respectively (p=0.059). The stone-free rate for groups 2R (95.0%) and 3R (98.0%) was higher than that for groups 2 (83.9%) and 3 (89.1%) (p=0.046; p=0.011).

CONCLUSION

These effortless modifications bring about a superior outcome when treating ureteral calculi with SWL.

Management of ureteric stones

The contemporary management of ureteric stones is reviewed and evidence based recommendations about treatment are made. Stones measuring less than 4mm in diameter have a high chance of spontaneous passage and the main debate for optimum treatment of larger stones centres around the choice of shock wave lithotripsy or endoscopic management combined with laser fragmentation. Treatment recommendations should be based on patient preference, published evidence, local audit (surgeon expertise and availability of equipment) and cost. Artificial Neural Networks could become a useful tool for prediction of treatment outcome for ureteric stones, and further research is needed to clarify this potential. ESWL is less effective than ureteroscopy but it may prevent the need for more invasive treatment in a substantial proportion of patients. It should only be considered as initial treatment in patients with stones less than 10mm in size. The routine use of stents should be avoided as both fragmentation and stone free rates are noticeably lower. For larger stones, initial laser ureteroscopy serves better both for proximal or distal calculi and is more cost-efficient. Provided that no contraindications for general anaesthesia exist, laser ureterolithotripsy should be regarded as an excellent first line treatment modality for ureteric stone especially in greater stone burden. In the best hands, the outcome for endoscopic management of ureteric stone in all sites is better than ESWL and is cheaper, although equipment, expertise and experience are all required to achieve this superior outcome.

Extracorporeal Shockwave Lithotripsy For Solitary Distal Ureteral Stones: Does the Degree of Urinary Obstruction Affect Success?

BACKGROUND AND PURPOSE

Extracorporeal shockwave lithotripsy (SWL) is a safe and effective way to treat stones in the distal ureter, but the impact of urinary obstruction on outcome is not clear. We investigated the relation between the degree of stone-induced urinary obstruction and the outcome of SWL treatment in patients with solitary distal ureteral stones.

PATIENTS AND METHODS

A series of 165 consecutive patients with solitary distal ureteral stones underwent SWL (Multimed 9200 Lithotriptor, Elmed Medical Systems, Turkey) between October 2002 and September 2003 at two separate centers. Distal ureteral stones were defined as those located below the lower border of the sacroiliac joint. Patients were divided into four groups according to the degree of stone-induced urinary obstruction: group I (N = 62) had no urinary system dilation; group II (N = 40) had mild dilation, group III (N = 35) moderate dilation, and group IV (N = 28) severe dilation. In addition to degree of obstruction, stone size, average fluoroscopy time, total number of shockwaves applied, number of sessions required to achieve stone-free status, and stone clearance time were recorded. Treatment failure was defined as persistence of fragments after three SWL sessions.

RESULTS

Overall, 152 (92.1%) of the patients became stone free after SWL. There were no statistically significant differences among the groups with respect to any of the factors studied.

CONCLUSION

In cases where there is a solitary calculus in the distal ureter, the degree of urinary obstruction caused by the stone does not affect the success of stone clearance with SWL.

Independent predictors of failure of shockwave lithotripsy for ureteral stones employing a second-generation lithotripter

PURPOSE

To define factors associated with the failure of shockwave lithotripsy (SWL) in the treatment of ureteral stones.

PATIENTS AND METHODS

We retrospectively studied 405 men and 283 women (mean age 52.6 years) who underwent SWL with a second-generation lithotripter in the period 1994 to 2001. We evaluated available clinical and radiologic features that might have been related to failure of SWL therapy.

RESULTS

Treatment was successful in 502 patients (73%). The 186 patients (27%) in whom treatment failed underwent endourologic alternatives or open surgery. Multivariate logistic regression analysis revealed that unsuccessful outcome was significantly related to: (1) pelvic ureteral stones (odds ratio [OR] 4.02; 95% CI 1.97, 8.19); (2) stone size >10 mm (OR 3.46; 95% CI 2.16, 5.53); (3) obstruction (OR 1.93; 95% CI 0.99, 3.77); and (4) obesity (OR 1.87; 95% CI 0.95, 3.77). Although the predictive value of each individual parameter was relatively low (15.3%-27.9%) the cumulative risk was 82.95% when patients had all four features. The strongest independent predictors of failure were pelvic stones and stones >10 mm (cumulative predictive value 57.3%).

CONCLUSIONS

These variables may enable identification of a subgroup of patients who will fail initial SWL. These patients may be candidates for endourologic alternatives as first-line treatment.

Hit/Miss monitoring of ESWL by spectral Doppler ultrasound

The objective of this study was to investigate spectral Doppler ultrasound (US) for monitoring extracorporeal shock-wave lithotripsy (ESWL). In vitro experiments with model stones showed that Doppler spectra acquired after a shock wave hit result in a high peak followed by a decaying signal. The duration of decay was dependent on shock-wave energy, stone size, gas content of the water and the level of disintegration. It typically ranged from 30 ms to 150 ms. It was found, by comparison with optical high-speed imaging and US B-scan imaging, that the signal originated from fragments released by the stone and cavitation. If the monitored volume contained no target, the signal duration was significantly shorter. By this means, hits were reliably distinguished from misses. The results of clinical treatments were highly consistent with those of in vitro experiments. Therefore, spectral Doppler US is an excellent tool for hit/miss monitoring in ESWL.

Factors associated with failure of extracorporeal shock-wave lithotripsy for ureteral stones using Dornier lithotripter U/50

BACKGROUND

In the present series of 170 patients who underwent extracorporeal shock-wave lithotripsy (SWL) treatment for ureteral stones, the authors determine which patients with ureteral stones had an unsuccessful outcome.

METHODS

The records of 170 patients with ureteral stones who were treated with SWL using the Dornier lithotriptor U/50 (EMSE 140) between January 1998 and December 1999 were retrospectively investigated. One hundred and thirty-one patients were treated with SWL alone (single session, n = 98; multiple session, n = 33) and 39 patients required auxiliary treatment due to failure of SWL (33 with transurethral ureterolithotripsy (TUL), one with open lithotomy, and five with residual fragments who were followed up). These two groups were compared using multivariate logistic regression analysis.

RESULTS

Lower ureteral stones and stones more than 12 mm in diameter were associated with a poor outcome of SWL. There were no significant differences in age, gender, number of stones, JJ stent placement, and degree of ureteral obstruction due to the stone between the two groups. The odds ratios of lower ureteral stones and stones > or = 12 mm were 4.18 and 2.57, respectively.

CONCLUSION

Patients with distal ureteral stones and/or stones more than 12 mm in diameter were difficult to treat successfully with SWL. Alternatives such as TUL should possibly be considered as a first-line therapy for these stones.

Management of ureteral stones in pediatric patients

PURPOSE

We report our 5-year experience in the management of ureteral stones in pediatric patients using shockwave lithotripsy (SWL) in combination with ureteroscopy.

PATIENTS AND METHODS

A total of 25 children (age range 12 months-14 years; mean 8.7 years) underwent SWL for ureteral lithiasis. Stones were located in the upper ureter in 6 children (24%), the middle ureter in 8 (32%), and the lower ureter in 11 (44%). Their size ranged from 5 to 14 mm (mean 10.9 mm). The children who failed SWL underwent ureteroscopic treatment.

RESULTS

In the SWL-only group, the overall stone clearance rate at 3 months was 84% (21 of 25 children). Four children (16%) who failed SWL underwent successful ureteroscopic treatment. Complications were infrequent and generally minor in both groups.

CONCLUSIONS

Shockwave lithotripsy is a safe and efficient treatment modality for ureteral stones in pediatric patients. In expert hands, ureteroscopy can be successfully applied in case of SWL failure.

A 10-year experience of managing ureteric calculi: changing trends towards endourological intervention--is there a role for open surgery?

OBJECTIVES

To study changing practices in the management of ureterolithiasis with the introduction of newer technologies, the efficacy and safety of endourology, extracorporeal shock wave lithotripsy (ESWL) and open surgery, and to determine if any indication remains for open ureterolithotomy in a tertiary endourology unit.

PATIENTS AND METHODS

A 12-year retrospective review (1987-1998) was conducted of all primary ureteric stones treated by ESWL, endoscopy, intracorporeal shock wave lithotripsy (ISWL) administered via ureteroscopy, and open surgery.

RESULTS

In all, 1195 patients were treated for primary ureteric stones, 44% by ESWL, 37% by ureteroscopy and ISWL, and 20% by open surgery. At the 3-month follow-up the stone-free rates for ESWL monotherapy, ureteroscopy and open surgery were 95%, 85% and 97%, giving an efficiency quotient of 73%, 64% and 94%, respectively. The overall complication rate for ESWL was 13%, for ISWL 32% and for open surgery 13%, but the complications of open surgery were often serious and potentially life-threatening.

CONCLUSIONS

With recent advances in endourology the indications for open surgery have decreased considerably, from 26% in 1987-95 to 8% in 1996-98. However, the remaining indications for open ureterolithotomy include failure of less invasive modalities, the presence of medical/anatomical abnormalities, a concomitant open procedure, and the presence of large impacted calculi for which patients prefer to avoid multiple procedures.

Impact of power index, hydroureteronephrosis, stone size, and composition on the efficacy of in situ boosted ESWL for primary proximal ureteral calculi

OBJECTIVES

The efficacy, safety, feasibility, and outcome of in situ treatment applied to select proximal ureteral calculi was assessed and analyzed with a view to avoiding auxiliary interventions and providing high clearance rates in the shortest possible time. We studied the impact of several clinically important variables, including power index, degree of hydroureteronephrosis (HDUN), stone size, and composition on the efficacy of sequential in situ boosted extracorporeal shock wave lithotripsy (ESWL) in a select group. The power index requirement for the in situ boosted protocol and the impact of the stone size/composition, degree of HDUN, and clearance rates were also analyzed.

METHODS

An in situ (no instrumentation) boosted protocol was applied to 130 primary unimpacted proximal ureteral calculi with no prior intervention. A typical session with the Siemens Lithostar Plus comprised 3000 shock waves, in installments of 500, deployed at a power setting of 1 to 4 kV with a gradual stepwise escalation. Sequential boosted additional sessions of ESWL were administered on days 2, 7, and 14, tailored to the degree of fragmentation, clearance status, and amount of residual stone bulk. Several parameters (shock waves, kilovolts used, fluoroscopy time, number of sessions, stone size, composition, fragmentation, clearance, and HDUN) were recorded and the results analyzed statistically.

RESULTS

The results were excellent in 83.8%, with a mean duration to complete clearance of 11.3 days. In situ ESWL failed in 7.69%, and the auxiliary intervention rate was 10.7%. Pre-ESWL HDUN was present in 78.3%, the mean power index was 184.6/session/case, and the average stone burden was 8.9 mm(2). Calcium oxalate monohydrate was the most common stone (56%). Renal colic was the most common side effect observed. The power index, fragmentation at the first session, and stone size were found to be the most favorable significant variables affecting stone clearance. The degree of HDUN, number of sessions, and stone composition did not significantly impact the clearance rates.

CONCLUSIONS

In situ boosted ESWL should be the first-line therapeutic modality in select unimpacted primary proximal ureteral stones.

Therapeutic efficacy of Dornier MPL 9000 for prevesical calculi as judged by efficiency quotient

PURPOSE

To study the efficacy and safety of the Dornier MPL 9000 lithotripter in the treatment of prevesical calculi using real-time ultrasound monitoring and to see if efficacy is adequately judged by the efficiency quotient (EQ).

PATIENTS AND METHODS

Seventy-six patients underwent ultrasound-guided extracorporeal shockwave lithotripsy (SWL) for prevesical calculi over a period of 43 months. Their age ranged from 8 to 68 (mean 37.6) years, and the male:female ratio was 2.6:1. The size of the stones, measured in two dimensions, ranged from 4 to 25 mm (mean 9.3 mm) and 2 to 15 mm (mean 6.0 mm). No general or regional anesthesia or ureteral stents were used, and all patients were treated in the prone position. The EQ was calculated using the formula: Stone free (%) x 100/(100 + retreatment rate (%) + auxiliary procedures (%).

RESULTS

Seventy patients were stone free in a mean time of 15 +/- 14.11 days. The average number of shockwaves used was 2,831 +/- 1,612, and the average number of sessions per patient was 1.7. About 92% of the patients were rendered stone free using in situ SWL alone. No major complication was encountered, and none of the patients required an inpatient stay after SWL. The EQ was 65. Five patients with failed SWL subsequently were rendered stone free, four with salvage ureteroscopy and pneumatic lithotripsy and one with cystolitholapaxy for a symptomatic fragment in the bladder. One patient was lost to follow-up.

CONCLUSION

In situ SWL is a safe and effective treatment for prevesical calculi. It should be used as a first-line treatment for most such stones. Efficiency can be assessed objectively by the EQ.

Two-year experience with ureteral stones: extracorporeal shockwave lithotripsy v ureteroscopic manipulation

Extracorporeal shockwave lithotripsy (SWL) and ureteroscopic manipulation became the standard treatments for ureteral stones in recent years. There still exists significant debate as to the most appropriate treatment modality for ureteral stones. During a period of 2 years, from January 1994 to December 1995, 651 patients with ureteral stones were treated, and 589 patients were retrospectively reviewed, excluding 62 patients with incomplete follow-up. Four hundred forty-two patients were treated with SWL using the MPL 9000 with ultrasonic guidance and 115 patients with ureteroscopic manipulations using 7.9F to 11.5F rigid and semirigid ureteroscopes. In SWL treatments, the overall stone-free rate was 74.7% with one session. The stone-free rate was significantly affected by the size of stones, being 83.6% when the stone was <1.0 cm and 42.1% when the stone was >1.0 cm. The stone-free rate after a second SWL session was 84.4% and was 90.3% after a third session. The stone-free rates according to the site of the stone were 72.4 (proximal), 70.0 (mid), and 80.2% (distal) after a single session. In ureteroscopic manipulation, an overall stone-free rate of 87.8% was obtained regardless of the size of the stones. The success rates according to the location of stones were 75.0 (proximal), 94.6 (mid), and 86.4% (distal). Open ureterolithotomy was performed in 32 patients, with a 100% success rate. In our study, the size of the stones was the most important factor influencing the success rate of SWL treatment. We consider ureteroscopic manipulation as the first-line treatment modality when the stone is >1.0 cm, especially if it is in the distal ureter. Proper selection of patients for in situ SWL or ureteroscopy would improve the results of initial treatment.

Echo-guided SWL of vesical stones with Dornier MPL 9000 lithotripter in obstructed and unobstructed patients

Sixty-one patients with vesical stones (38 with underlying obstructive conditions and 23 unobstructed) underwent SWL using ultrasound targeting under no regional or general anesthesia. A foley catheter was not routinely employed, and the bladder was filled in a physiologic way. Complete resolution was obtained in 47 patients (78%); in particular, 66% of the obstructed patients and 96% of the unobstructed patients became stone free in one to four SWL sessions. The average number of sessions for all patients was 1.28+/-0.63. Fragments were completely evacuated also in some patients with severe obstruction and in all three patients with neurogenic bladder dysfunction. The size and number of stones did not seem to play a limiting role in SWL effectiveness: the principal limiting factor was the hardness of the stone. No severe complications occurred. However, in six patients (10%), some fragments stopped in the urethra, causing acute urine retention, and endoscopic extraction was necessary. Echo-guided SWL of bladder stones is safe and highly effective in nonobstructed patients and can be considered the elective monotherapy method. In obstructed patients, SWL efficacy is lower, but the method may be suggested for patients who refuse or delay other, more invasive techniques.

In situ piezoelectric extracorporeal shock wave lithotripsy of ureteric stones

OBJECTIVE

To evaluate the efficacy of the EDAP LT 02 lithotripter for the in situ treatment of ureteric calculi.

PATIENTS AND METHODS

One hundred consecutive patients presenting with ureteric calculi were treated with in situ piezoelectric extracorporeal shock wave lithotripsy (ESWL) using the EDAP LT 02 lithotripter. There were 49 patients with upper, nine with mid and 42 with lower ureteric stones. The largest diameter of the stones varied from 7 to 21 mm (mean 9.6 mm). Mild or severe hydronephrosis was present in 53 cases. Mid and lower ureteric stones were treated with the patients in the prone position, with no anaesthesia or pre-medication, and upper ureteric stones in the supine position, with intravenous sedation in 44 cases.

RESULTS

Localization of the stones was easy in 81 cases and more difficult in 19, but an intravenous pyelogram was only necessary in three cases. The number of sessions per patient varied from 1 to 3 (mean 1.17). Complete success rate was achieved in 75% of patients and partial success (residual stones < or = 3 mm) in 6%. The stone-free rate was statistically affected by stone size but was independent of stone localization or the degree of obstruction. The rate of infective and obstructive complications was 14% and auxiliary treatments were necessary in 5% of patients.

CONCLUSION

In situ piezoelectric ESWL with the EDAP LT 02 device is a convenient and efficient method for the treatment of ureteric stones.