Intracorporeal Electrohydraulic Lithotripsy of Ureteral and Renal Calculi Using Small Caliber (1.9F) Electrohydraulic Lithotripsy Probes

Influence of Ureteral Stone Components on the Outcomes of Electrohydraulic Lithotripsy

Purpose

We evaluated the influence of urinary stone components on the outcomes of ureteroscopic removal of stones (URS) by electrohydraulic lithotripsy (EHL) in patients with distal ureteral stones.

Materials and Methods

Patients with a single distal ureteral stone with a stone size of 0.5 to 2.0 cm that was completely removed by use of EHL were included in the study. Operating time was defined as the time interval between ureteroscope insertion and complete removal of ureteral stones. Ureteral stones were classified into 5 categories on the basis of their main component (that accounting for 50% or more of the stone content) as follows: calcium oxalate monohydrate (COM), calcium oxalate dihydrate, carbonate apatite (CAP), uric acid (UA), and struvite (ST).

Results

A total of 193 patients (131 males and 62 females) underwent EHL. The mean operating time was 25.1±8.2 minutes and the mean stone size was 1.15±0.44 cm. Calcium oxalate stones accounted for 64.8% of all ureteral stones, followed by UA (19.7%), CAP (8.3%), and ST (7.2%) stones. The mean operating time was significantly longer in the UA group (28.6±8.3 minutes) than in the COM group (24.0±7.8 minutes, p=0.04). In multivariate analyses, the stone size was negatively associated with the odds ratio (OR) for successful fragmentation. UA as a main component (OR, 0.42; 95% confidence interval, 0.20 to 0.89; p=0.023) was also found to be significantly important as a negative predictive factor of successful fragmentation after adjustment for stone size.

Conclusions

The results of the present study suggest that successful fragmentation by URS with EHL could be associated with the proportion of the UA component.

[Retrograde intrarenal surgery (RIRS). Technical complement for cases of acute lithiasis]

INTRODUCTION

Washing the renal cavities using minipercutaneous surgery shaft is an ideal technical procedure for retrograde intrarenal surgery (RIRS) when lithiasic fragmentation is significant or if the anatomy of the renal cavities may obstruct the spontaneous elimination of fragments.

MATERIALS AND METHODS

we performed 37 RIRS on 35 patients with renal lithiasis (14 men, 21 women) with a mean age of 56 (range 33-72) years, divided into two groups in accordance with the size of their kidney stones. Group A, 23 patients with lithiasis <1.5 cm; Group B, 12 cases with lithiasis >1.5 cm. 28 patients had a single kidney stone and 7 had multiple stones.

APPROACH

Flexible uretrorenoscopy, 7.5 Fr (Flex-X(®, Karl Storz) by means of a ureteral access sheath. Holmium laser lithotripsy (Calculase®, Karl Storz) using 200 and 365 micrometer fibres. Fragment extraction with 1.7 Fr nitinol baskets (N-gage, Cook). In cases of significant fragmented stone burden, the renal cavities were washed with low-pressure fluid irrigation using a ureteral access sheath, which was collected together with the stone fragments carried by the "mini-perc" sheath (Ultrax-x® 18Fr, Cook; Rusch, 14 Fr) placed under radiologic and endoscopic control at the level of the calyx-papilla selected for fragment drainage.

RESULTS

the mean diameter for group A was 9.13 (range 5-13) mm and 20.25 (range 16-28) mm for group B. The overall mean operating time was 81 (range 30-160) min. Group A required 66.43±35.18 min. and group B 107.5±46.73 min. (p=0.006). The rate of absence of stones immediately after surgery was 83.2%, 93.1% at 3 months (95.6% for A and 83.3% for B; p=0.217). In no case was ureteral stenosis observed as a result of the use of ureteral access sheaths. In 7 group B patients (58.3%) with acute lithiasis and/or alteration in their pyelocaliceal anatomy, we performed active lavage of the renal cavities applying the aforementioned percutaneous technique. The mean post-surgery hospital stay was 2.1 (range 1-4) days. There were post-surgery complications (Clavien 1) in 7 patients (20%). Two patients required a second FURS.

CONCLUSIONS

RIRS can be effective treatment for renal lithiasis >1.5 cm. Lavage of the renal cavities helps to eliminate stone fragments, reducing the possibility of retreatment.

Ureteroscopic ultrasound technology to size kidney stone fragments: proof of principle using a miniaturized probe in a porcine model

PURPOSE

A prototype ultrasound-based probe for use in ureteroscopy was used for in vitro measurements of stone fragments in a porcine kidney.

METHODS

Fifteen human stones consisting of three different compositions were placed deep in the collecting system of a porcine kidney. A 2 MHz, 1.2 mm (3.6F) needle hydrophone was used to send and receive ultrasound pulses for stone sizing. Calculated stone thicknesses were compared with caliper measurements.

RESULTS

Correlation between ultrasound-determined thickness and caliper measurements was excellent in all three stone types (r(2) = 0.90, p < 0.0001). All 15 ultrasound measurements were accurate to within 1 mm, and 10 measurements were accurate within 0.5 mm.

CONCLUSION

A 3.6F ultrasound probe can be used to accurately size stone fragments to within 1 mm in a porcine kidney.

Lower calyceal occlusion by autologous blood clot to prevent stone fragment reaccumulation after retrograde intra-renal surgery for lower calyceal stones: first experience of a new technique

PURPOSE

We tested the hypothesis that lower calyceal (LC) autologous blood clot (ABC) occlusion, after retrograde intra-renal surgery (RIRS) may prevent LC fragment reaccumulation where all fragments cannot be directly removed.

METHODS

Over two years, patients with LC stones >6 mm <2 cm, that had presented de-novo or failed primary SWL or PNL elsewhere, were treated with RIRS. After intra-renal relocation into a favorable lie, stones were fragmented with Holmium laser energy to <3 mm, suitable for spontaneous passage. The LC was filled with 5-10 cc venous autologous blood with the patient in reverse Trendelenberg, leaving the blood to clot. After confirmatory pyelogram a DJ stent was placed. Ultrasound and KUB at 3 months assessed stone free rate.

RESULTS

This technique was tested in 35 patients with LC calculi (16 as primary treatment, and 19 as salvage for residual fragments post SWL or PNL). Nine salvage patients had indwelling DJ stents (three significantly encrusted at RIRS). Nine unstented patients had upper ureteral tortuosities or narrowing limiting multiple instrument passes for stone removal. Median maximum stone dimension was 1.2 cm. All were successfully relocated & fragmented. A Nitinol basket was required for stone relocation in 60%. All but one occlusion procedures succeeded at the first attempt. None required re-admission for clot colic. Only 8.6% required more than overnight hospital stay. Three and six month stone free rates were 94% and 97% respectively.

CONCLUSIONS

The simple LC autologous blood clot occlusion technique after RIRS, for difficult LC stones, validates our hypothesis and results in excellent stone free rates, while minimizing ureteral trauma from multiple instrument passages needed for active fragment removal. This study supports the need for multi-center experience of this technique to validate our results.

Ureteroscopic management of lower ureteric calculi: a 15-year single-centre experience

OBJECTIVE

To review our 15-year experience with ureteroscopic treatment of distal ureteric calculi and to determine the impact of improved technology and techniques on the efficacy, success and complications of the procedure.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of 4512 patients who underwent 5133 ureteroscopic procedures for the treatment of distal ureteric calculi at our institution from January 1991 to December 2005. The patient and stone characteristics, treatment variables and clinical outcomes were assessed. Factors such as type of ureteroscope, procedure duration, procedure success, complication rate and hospital stay were evaluated. Data obtained from a cohort of patients that underwent the procedure from 1991 to 1995 (group 1) were statistical compared with those obtained from a cohort of patients from 1996 to 2005 (group 2). Logistic regression analysis was used to identify associated factors with the major complications of ureteroscopy.

RESULTS

Overall, the stone-free rate after the procedure was 94.6%, the mean (sd; range) operative duration was 43 (15.0; 25-120) min, the intraoperative complication rate was 6.67%, the postoperative complication rate was 9.9%, and the mean (sd) hospital stay was 1.7 (1.1) days. The clinical and radiological follow-up (mean 36.8 months) for 71.3% of eligible patients detected only 12 ureteric strictures (0.23%). On comparing group 1 with group 2, the overall success of ureteroscopic stone extraction improved from 85.7% to 97.3% (P < 0.001), significant ureteric perforation decreased from 3.3% to 0.5% (P = 0.05), ureteric avulsion decreased from 1.3 to 0.1% (P < 0.05), ureteric stricture decreased from 0.7% to 0.1% (P < 0.007), the mean (sd) procedure time significantly decreased from 75 (42.9) min to 36.5 (12.5) min (P < 0.001), and the mean hospital stay significantly decreased from 2.5 (1.6) days to 0.5 (1.2) days, with a trend toward outpatient treatment. Logistic regression analysis showed a significant association of the major ureteroscopic complications with increased operative duration, type of ureteroscope used, stone impaction, stone size and surgeon experience.

CONCLUSION

The present series shows the high success rate, with minor complications, that can be achieved with ureteroscopic treatment of distal ureteric calculi. Improvements in ureteroscope design, accessories, technique and experience have led to a significant increase in the success rate and decrease in the complication rate.

Combined Electrohydraulic and Holmium:YAG Laser Ureteroscopic Nephrolithotripsy of Large (Greater Than 4 cm) Renal Calculi

PURPOSE

Percutaneous nephrolithotripsy is standard treatment for renal calculi larger than 2 cm. Modern flexible ureteroscopes and accessories using the complimentary effects of electrohydraulic lithotripsy and holmium:YAG laser lithotrites can treat large (greater than 4 cm) branched renal calculi in a minimally invasive fashion with similar or superior results. This report is an assessment of the safety and efficacy of ureteroscopic nephrolithotripsy monotherapy for the management of large (greater than 4 cm) branched renal calculi in the community setting.

MATERIALS AND METHODS

A total of 16 patients with 17 branched renal calculi ranging from 41 to 97 mm (mean 65) in length and 560 to 2,425 mm2 (mean 1,169) in area underwent staged ureteroscopic nephrolithotripsy monotherapy. Obesity (body mass index greater than 30) was present in 81% and 38% were morbidly obese (body mass index greater than 40). An infectious etiology was present in 81% and hard stone components were present in 94%. All patients presented with hematuria, pain and/or recurrent urinary tract infection. Lithotripsy was performed with a single deflection flexible ureteroscope and predominantly electrohydraulic lithotripsy. Laser drilling was used (in 4) to weaken hard stones before electrohydraulic lithotripsy. Low intrarenal pressure was maintained by continuous bladder drainage and placement of a stiff safety wire. Visibility was maintained using manual pulsatile irrigation.

RESULTS

All patients were rendered pain and infection-free. No patient required a blood transfusion and there was no change in serum creatinine. Mobile stone-free status was achieved in 15 of 17 renal units (88%) with a mean of 2.4 stages and 36 of 40 (90%) procedures performed on an outpatient basis. Operative time averaged 49 minutes per stage and 115 minutes per calculus. There were 3 patients admitted for fever and 1 patient (90 years old) admitted for pneumonia 3 days postoperatively. There were also 3 patients with calculi larger than 75 mm who required ureteroscopic management of steinstrasse.

CONCLUSIONS

Staged ureteroscopic nephrolithotripsy of large renal calculi is feasible with low morbidity and stone clearance rates that compare favorably with percutaneous nephrolithotripsy.

Retrograde intrarenal surgery as second-line therapy yields a lower success rate

BACKGROUND AND PURPOSE

Retrograde intrarenal surgery (RIRS) is a recent addition to the treatment options for renal calculi. Therefore, the indications, as well as the predictors of success, are still being studied. Herein, we report a retrospective comparison of RIRS performed as the primary treatment and as second-line therapy, mostly after shockwave lithotripsy (SWL) failure.

PATIENTS AND METHODS

Between October 2001 and August 2004, 93 patients underwent RIRS (11% of all ureteroscopies), all by the same surgeon. Patients were divided into two groups: group 1 (n = 42) consisted of patients undergoing RIRS as a first-line modality and group 2 (n = 51) of those having RIRS as secondline therapy. The indications for RIRS in group 1 were renal calculi with prior placement of a double-J stent (30%), renal + ureteral stone (25%), pushback of ureteral stone during ureteroscopy (22%), a radiolucent stone (8%), coagulopathy, and abnormal renal anatomy. In group 2, the patients were initially treated by SWL (92%) or percutaneous nephrolithotomy. The groups did not differ significantly in demographic characteristics, mean stone size (9.5 and 8.7 mm, respectively), or stone location (in both 60% in the lower pole). The variables analyzed were operating time, complications, length of hospitalization, and stone-free rate.

RESULTS

The overall stone-free rate was 73%. However, the stone-free rate was significantly higher in group 1 than in group 2: 80% v 67%, respectively. A higher complication rate and longer hospitalization were noted in group 2, although the difference was not statistically significant.

CONCLUSIONS

When RIRS is performed after failed SWL, it has a lower success rate and may be associated with a higher morbidity rate than if it is performed as first-line therapy. These results suggest that the success rate of RIRS may be influenced by the same negative factors that reduce SWL success. Therefore, if a patient fails SWL, careful consideration should be given to the best second-line therapy comparing RIRS with percutaneous stone removal.

Treatment of impacted lower third ureteral stones with the use of the ureteral access sheath

We present our experience with the use of the ureteral access sheath for the management of small impacted lower third ureteral stones, in comparison with more standard techniques. Ninety-eight consecutive patients, aged 18-73 years (mean 48.5), with small (diameter < or = 10 mm) impacted lower third ureteral stones (< 5 mm in 56, and 5-10 mm in 42 patients) were randomly managed with either a 12/14F coaxial ureteral dilator/sheath and a 7.5F flexible ureteroscope (group A; 48 patients), or with balloon dilatation and the 7.5F flexible ureteroscope (group B; 50 patients). In both groups, stones were grasped and extracted with a basket, and when necessary they were disintegrated with a 1.9F electrohydraulic lithotripsy (EHL) probe. Postoperatively, excretory urography was performed at 1 month and patients were followed-up for 1 year. The mean operative time was 45.5 min in group A, and 58.5 min in group B (P<0.05). EHL was performed in 16 (33.3%) patients of group A, and in 12 (24%) patients of group B. In group B, balloon dilatation was performed in 28 (56%) patients. Ureteral perforation was revealed in 4 (8%) patients of group B. The follow-up imaging tests showed stone-free status in 46 (95.8%) patients of group A and in all (100%) patients of group B. No long-term complications were recorded. Endoscopic management of small impacted lower third ureteral stones with the ureteral access sheath is a quicker and safer procedure, in comparison with the more standard approach, bearing comparable efficacy.

Prospective, randomized trial comparing shock wave lithotripsy and ureteroscopy for lower pole caliceal calculi 1 cm or less

PURPOSE

The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial.

MATERIALS AND METHODS

A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures.

RESULTS

A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL.

CONCLUSIONS

This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.

COMBINED ELECTROHYDRAULIC AND HOLMIUM:YAG LASER URETEROSCOPIC NEPHROLITHOTRIPSY FOR 20 TO 40 MM RENAL CALCULI

PURPOSE

Percutaneous nephrolithotripsy is standard treatment for renal calculi greater than 2 cm. Modern flexible ureteroscopes using the complementary effects of electrohydraulic (EHL) and Ho:YAG laser lithotrites can treat 2 to 4 cm renal calculi in minimally invasive fashion with similar or superior results. We evaluated the safety and efficacy of ureteroscopic nephrolithotripsy for the management of 2 to 4 cm renal calculi in a community setting.

MATERIALS AND METHODS

Between January 2001 and November 2002 all 15 patients presenting with renal calculi 22 to 42 mm long (mean 33) and 275 to 650 mm in area (mean 396), of whom 40% had infection, underwent flexible ureteroscopic nephrolithotripsy. A total of 13 patients had 3-month followup data. Hard stone components, namely calcium oxalate monohydrate and/or apatite, were present in 13 cases (87%). Treatment principles were the aggressive treatment of infection, EHL stone debulking, Ho:YAG laser lithotripsy to weaken hard stones structurally, manual piston irrigation to maintain visibility, bladder drainage to maintain low intrarenal pressures, minimum 6-hour postoperative observation and physiological passage of stone fragments.

RESULTS

In the 13 patients with 3-month followup data the stone clearance rate was 92% for complete stone free status and 100% for fragments less than 4 mm. This result was achieved at 1 stage in 10 cases 13 (77%) and at 2 to 4 stages in 1 each. Mean procedure time per stage was 47 minutes (range 25 to 90) and total procedure time per patient was 66 minutes (range 25 to 240). There was no significant change in mean preoperative and postoperative hemoglobin (p = 0.87) and creatinine (p = 0.85) in the 16 of 21 procedures for which data were available. Procedures were done on an outpatient basis except in 1 patient, who was hospitalized overnight for the management of preexisting pulmonary problems. One rehospitalization for colic management but no other unplanned emergency department or clinic visits occurred. All patients were rendered infection-free and symptom-free.

CONCLUSIONS

Combined EHL and Ho:YAG laser flexible ureteroscopic lithotripsy can be an effective treatment with low morbidity. As such, it provides an attractive, minimally invasive alternative to percutaneous nephrolithotripsy or open surgery in patients with 2 to 4 cm renal calculi.

Ureteroscopic treatment of renal calculi

Although ureteroscopic treatment of renal calculi is safe and effective. it is relatively inefficient compared with ESWL and PCNL. It should be considered primary therapy for patients with lower pole stones who have adverse ESWL characteristics and patients who are not suitable candidates for PCNL. There are also numerous clinical situations, as outlined previously, where the ureteroscopic approach is favored over other treatment modalities.

Retrograde intrarenal lithotripsy outcome after failure of shock wave lithotripsy

PURPOSE

We report our experience with retrograde intrarenal lithotripsy (RIRL) for renal stones not alleviated by shock wave lithotripsy (SWL).

MATERIALS AND METHODS

A total of 28 females and 53 males with a mean age of 53 years (range 18 to 86) were studied. They had been treated with a mean of 3.2 previous SWLs. Mean stone size was 9.2 mm (range 4 to 22) and the mean number of stones per patient was 1.27 (range 1 to 5) for a total of 103 stones overall. In 70 patients there was 1 stone. Rigid and flexible ureteroscopes were used in 8 and 67 cases, respectively, while a combined approach was used in 6. A holmium:YAG laser was used for fragmentation in 52 patients. Success was defined as stone-free status or residual fragments less than 3 mm.

RESULTS

The overall success rate was 67%. RIRL yielded a 46% stone-free rate. Of the 44 patients 17 (39%) had residual stones less than 3 mm, while 13 required ancillary procedures. There were no residual ureteral stones. Original stone size correlated inversely with the success rate. Most failures involved lower pole stones, in that laser fiber deflection prevented reaching them in 9 cases. The procedure was interrupted due to extravasation or bleeding in 5 patients and 6 had postoperative urinary tract infections (16% overall complication rate).

CONCLUSIONS

RIRL effectively and safely alleviated upper tract stones unresponsive to earlier SWL. It can be considered salvage therapy in such cases. RIRL is well suited for treating stones less than 2 cm with better stone-free rates than SWL in the same circumstances. Residual stones were more likely in lower pole cases.

Advanced intrarenal ureteroscopic procedures

The role of flexible ureteroscopy in the management of intrarenal pathology has undergone a dramatic evolution, powered by improvements in flexible ureteroscope design; deflection and image quality; diversification of small, disposable instrumentation; and the use of holmium laser lithotripsy. This article reviews the application of flexible ureteroscopy for advanced intrarenal procedures.

Removal of asymptomatic ipsilateral renal stones following rigid ureteroscopy for ureteral stones

PURPOSE

To evaluate the feasibility and outcome of flexible ureteroscopic removal of small (<1-cm) asymptomatic renal stone(s) following rigid ureteroscopy for ureteral stones.

PATIENTS AND METHODS

Ten female and nineteen male patients underwent rigid ureteroscopy and holmium lasertripsy for removal of ureteral stone(s). All had asymptomatic renal stone(s) on the same side, which were then removed using flexible ureteroscopy. The renal stones were either removed intact with a tipless Nitinol basket or fragmented with the laser to small pieces (<2 mm), with basket removal of larger fragments. The number and size of stones, total operative time, added time needed for flexible ureteroscopy, and intraoperative and postoperative complications were recorded. Follow-up at 1 month included a plain abdominal film and renal ultrasonography or noncontrast CT scan.

RESULTS

Fifty-six renal stones with a mean size of 5.7 mm were treated. Fourteen patients had stones on the right side, and 15 had stones on the left. The mean total operative time was 56.5 minutes, with a mean added time of 16.7 minutes for flexible ureteroscopy. Stones were removed intact in 18 patients and fragmented in 8 patients, resulting in an immediate success rate of 90%. There were three failures. One-month follow-up confirmed all patients were either stone-free or had residual fragments <2 mm in diameter, with no new-onset hydronephrosis.

CONCLUSIONS

Removal of small asymptomatic renal stones at the time of ureteroscopy for ureteral stones appears safe and effective and requires little additional operative time.

Practice patterns in the treatment of large renal stones

PURPOSE

To determine the current practice patterns of a large group of urologists in the treatment of large renal stones.

MATERIALS AND METHODS

A survey was sent to all actively practicing members of the North Central Section of the American Urological Association. The questions pertained to age, time in practice, type of practice, time devoted to treating stones, residency training, case scenarios with treatment options, and whether they or a radiologist performed percutaneous access. The data were statistically analyzed.

RESULTS

The response rate was 51% (564/1102 surveys returned). Three quarters (73%) of the urologists were comfortable performing percutaneous nephrolithotomy (PCNL), and 35% gave reasons they do not perform PCNL. Only 11% of those performing PCNL routinely obtained the percutaneous access themselves. Trends in the analysis included: (1) those trained to perform PCNL during residency were more often comfortable with this procedure; (2) younger urologists were more comfortable performing PCNL, even if they had been in practice for only a short time; (3) urologists in private practice were nearly as comfortable performing PCNL as were academic urologists; (4) urologists not comfortable with PCNL more often recommended SWL over PCNL as a primary treatment for moderate/large renal stones; and (5) few urologists routinely obtained percutaneous access themselves.

CONCLUSIONS

Many urologists trained in recent years are comfortable performing PCNL. The type of training received influences treatment recommendations, and percutaneous access is most often obtained by/in conjunction with radiologists. This information may be useful in guiding residency training programs in the preparation of residents for the treatment of large renal stones.

Current management of urolithiasis: progress or regress?

PURPOSE

To assess the impact of the development of less powerful second- and third-generation shockwave lithotripters on surgical stone therapy in light of recent advances in ureteroscopy and laser lithotripsy. As such, we sought to identify current trends in the treatment of stone disease, both at our university medical center and nationally, and to contrast them with the corresponding data from 1990.

PATIENTS AND METHODS

All urolithiasis procedures (ureteroscopy, SWL, open surgery, and percutaneous stone removal) performed in 1998 were compared with all urolithiasis procedures performed 8 years earlier (1990) at a single institution (Washington University, St. Louis). In addition, Medicare data for each year from 1988 through 2000 were collected from the Health Care Financing Administration to assess the national trends for open stone surgery, ureteroscopic stone removal, SWL, and percutaneous nephrolithotomy.

RESULTS

At Washington University, the number of percutaneous stone removals remained stable; however, the overall number of ureteroscopies increased by 53%, while the number of SWLs, decreased by 15%. The Medicare data likewise reflect a marked decrease in open stone surgery and a marked increase in ureteroscopic stone surgery with a slight increase in SWL. Utilization of percutaneous nephrolithotomy remained unchanged.

CONCLUSIONS

We believe this trend toward ureteroscopy is attributable to several factors: improved, smaller rigid and flexible ureteroscopes; the availability of more effective intracorporeal lithotripters (e.g., pneumatic and holmium laser), and the lack of development of lower cost, more effective SWL. This is an unfortunate trend, as we are moving away from the noninvasive treatment that was the hallmark of urolithiasis therapy at the beginning of the last decade toward more invasive endoscopic therapy. Increased research efforts in SWL technology are sorely needed.

Holmium:YAG laser lithotripsy for upper urinary tract calculi in 598 patients

PURPOSE

We assessed the effectiveness and safety of holmium:YAG laser lithotripsy for managing upper urinary tract calculi in a prospective cohort of 598 patients.

MATERIALS AND METHODS

Ureteroscopic holmium:YAG laser lithotripsy was performed in 598 patients between 1993 and 1999. Calculi were located in the distal ureter in 39.6% of cases, mid ureter in 18.6%, proximal ureter in 32.4% and kidney in 9.4%. Patients were treated on an outpatient basis with various flexible and semirigid endoscopes. Of the cases 59% were referred as previous treatment failures. Patients were assessed 6 to 12 weeks postoperatively with repeat plain x-ray and ultrasound or excretory urography for late obstructive complications.

RESULTS

The overall stone-free rate was 97%. As stratified by location, the stone-free rate was 98% in the distal ureter, 100% in the mid ureter, 97% in the proximal ureter and 84% in the kidney. Fragmentation was incomplete in 6% of cases and secondary intervention was required in 6%. The overall complication rate was 4%. New onset ureteral stricture developed postoperatively in 0.35% of patients.

CONCLUSIONS

Holmium:YAG laser lithotripsy is a highly effective and safe treatment modality for managing ureteral and a proportion of intrarenal calculi on an outpatient basis. The effectiveness and versatility of the holmium laser combined with small rigid or flexible endoscopes make it our modality of choice for ureteroscopic lithotripsy.

Flexible ureteroscopy in conjunction with in situ lithotripsy for lower pole calculi

OBJECTIVES

To demonstrate the efficacy and safety of ureteroscopy as a compromise in treating small and intermediate-size lower pole calculi. The optimal management of lower pole calculi remains controversial. Shock wave lithotripsy is associated with minimal morbidity but with suboptimal stone clearance rates. Conversely, percutaneous nephrostolithotomy has greater morbidity but stone-free rates greater than 90% regardless of size.

METHODS

Seventy-two patients underwent ureteroscopy for lower pole calculi 2 cm or less (mean 8.7 mm) during a 3-year period. To minimize confounding, 11 patients with additional calculi at other ipsilateral renal sites and 1 patient with large (2.4 cm each) bilateral calculi were excluded. Two patients with bilateral lower pole calculi and four who required a second procedure were included in the analysis. Thus, the final cohort consisted of 60 patients who underwent 66 procedures.

RESULTS

Of patients with follow-up longer than 1 month, 79% were stone free after a single procedure, and this improved to 88% after a second procedure in 4 patients. All 7 patients with follow-up less than 1 month had a reduction in stone burden after successful fragmentation. Overall, 8 patients required an auxiliary procedure. No intraoperative complications, and 7 (11%) postoperative complications occurred.

CONCLUSIONS

Ureteroscopy for lower pole calculi is associated with minimal morbidity and stone-free rates comparable to shock wave lithotripsy for smaller stones. The greatest utility of ureteroscopy is in the management of intermediate-size calculi, for which it has substantially higher stone-free rates and lower repeated treatment rates than does shock wave lithotripsy.

Retrograde ureteropyeloscopic holmium laser lithotripsy for large renal calculi

OBJECTIVE

To assess the efficacy and safety of the retrograde ureteropyeloscopic holmium laser for treating renal stones that are too large to treat with extracorporeal shock wave lithotripsy (ESWL).

PATIENTS AND METHODS

Thirty patients (22 men and eight women, mean age 43 years, range 18-62) with a renal stone burden of > 2 cm were selected for laser treatment. The stones were in the renal pelvis in 16 patients, lower calyx in five, middle calyx in two, upper calyx in one and multiple pelvic and calyceal in six. Lithotripsy was undertaken using a holmium laser through 550 microm and 200 microm laser fibres passed through a semi-rigid fibre-optic long ureteroscope or the actively deflectable flexible ureteropyeloscope, respectively. Success was defined as total fragmentation of the stone to < 2 mm in diameter and/or clear imaging on renal ultrasonography and plain films within the 3-month follow-up. Patients in whom the treatment failed received either alternative therapy or complementary ESWL.

RESULTS

Endoscopic access and complete stone fragmentation was achieved in 23 of the 30 patients (77%). The treatment failed in seven patients because of poor visualization, the initial presence of stones in, or migration of their large fragments to, an inaccessible calyx. There were no major intraoperative complications. Minor complications after treatment included haematuria that persisted for 2 days in one patient and high-grade fever in two patients; all were treated conservatively.

CONCLUSION

Large renal calculi that are not amenable to ESWL monotherapy can be safely and effectively treated with a retrograde endoscopic technique that seems to compete well with the more invasive percutaneous or open surgical manoeuvres.

Lower pole I: a prospective randomized trial of extracorporeal shock wave lithotripsy and percutaneous nephrostolithotomy for lower pole nephrolithiasis-initial results

PURPOSE

The efficacy of shock wave lithotripsy and percutaneous stone removal for the treatment of symptomatic lower pole renal calculi was determined.

MATERIALS AND METHODS

A prospective randomized, multicenter clinical trial was performed comparing shock wave lithotripsy and percutaneous stone removal for symptomatic lower pole only renal calculi 30 mm. or less.

RESULTS

Of 128 patients enrolled in the study 60 with a mean stone size of 14.43 mm. were randomized to percutaneous stone removal (58 treated, 2 awaiting treatment) and 68 with a mean stone size of 14.03 mm. were randomized to shock wave lithotripsy (64 treated, 4 awaiting treatment). Followup at 3 months was available for 88% of treated patients. The 3-month postoperative stone-free rates overall were 95% for percutaneous removal versus 37% lithotripsy (p <0.001). Shock wave lithotripsy results varied inversely with stone burden while percutaneous stone-free rates were independent of stone burden. Stone clearance from the lower pole following shock wave lithotripsy was particularly problematic for calculi greater than 10 mm. in diameter with only 7 of 33 (21%) patients becoming stone-free. Re-treatment was necessary in 10 (16%) lithotripsy and 5 (9%) percutaneous cases. There were 9 treatment failures in the lithotripsy group and none in the percutaneous group. Ancillary treatment was necessary in 13% of lithotripsy and 2% percutaneous cases. Morbidity was low overall and did not differ significantly between the groups (percutaneous stone removal 22%, shock wave lithotripsy 11%, p =0.087). In the shock wave lithotripsy group there was no difference in lower pole anatomical measurements between kidneys in which complete stone clearance did or did not occur.

CONCLUSIONS

Stone clearance from the lower pole following shock wave lithotripsy is poor, especially for stones greater than 10 mm. in diameter. Calculi greater than 10 mm. in diameter are better managed initially with percutaneous removal due to its high degree of efficacy and acceptably low morbidity.

The management of urinary calculi in pregnancy

When a pregnant patient presents with a urinary calculus, the customary investigations and management must change in order to take into account the well-being of the developing fetus. Transabdominal or endovaginal ultrasound should be the initial imaging modality used in order to establish the diagnosis. A plain abdominal X-ray, limited intravenous pyelography, or retrograde pyelography is used secondarily if a definitive diagnosis is lacking. The treatment of first choice for urolithiasis in pregnancy is conservative, because 70-80% of stones will pass spontaneously. If conservative management fails, or in cases of sepsis, obstruction of a solitary kidney, or bilateral ureteric obstruction, then surgical intervention is indicated. Traditional surgical management consists of draining the obstructed collecting system with a ureteral stent or percutaneous nephrostomy tube with definitive treatment of the stone in the post-partum period. Ureteroscopic lithotripsy and stone extraction is another option that has been used safely and reliably with increasing frequency in many centers. Despite recent reports of using extracorporeal shock-wave lithotripsy, this treatment is still considered contraindicated in pregnancy.

Update on contact lithotripsy

Despite the development of extracorporeal shockwave lithotripsy, endoscopic stone removal, with or without intracorporeal lithotripsy, is still an effective minimally invasive alternative for special indications. There is no defined all-purpose lithotripsy procedure for contact lithotripsy. The choice of the lithotripsy procedure for endoscopic stone disintegration depends on a number of different factors, the main one being stone localization. Small calibre, flexible probes (electrohydraulic, pneumatic, laser) are especially appropriate for ureterorenoscopy, but the speed of stone disintegration is a limiting factor. In contrast, large calibre rigid probes (ultrasound) are clearly more effective, but are unsuitable in size for flexible ureterorenoscopy. This indicates that the type and size of the endoscope decisively influences the choice of devices for endoscopic stone disintegration. Additional inhibiting factors are the flexibility or the rigidity of the instrument and the diameter of the working channel. It must be noted that total costs are not only calculated on the purchase of the equipment, but must also cover disposable materials.

Intracorporeal lithotripsy. Update on technology

The number and variety of devices currently available for endoscopic lithotripsy reflect the reality that no single device is ideal in all situations. Although the search for the universal lithotriptor continues, the urologist must consider several factors if faced with the decision of which device to purchase. Perhaps foremost among these factors is the clinical situation with which one commonly deals. For example, although the smaller, flexible probes such as EHL or laser demonstrate considerable utility if used ureteroscopically, the larger stone burden associated with today's percutaneous nephrolithotripsy population often is treated more efficiently with one of the mechanical devices employing a larger, rigid probe, such as ultrasound or the Lithoclast. Similarly, the type and size of endoscopic equipment at one's disposal have a significant impact on which device to purchase or use. There are physical constraints affecting which device may or may not be used, rigid versus flexible endoscope, working channel caliber, and offset versus end-on-port. The skill and experience of the surgeon is also a factor of obvious importance, particularly if one is using a modality with a relatively narrow margin of safety such as EHL. Likewise, the training and experience of nursing personnel is a factor, especially regarding the use of lasers, which require certified personnel who are well versed in laser safety. Finally, in today's environment one must carefully evaluate cost in terms of not only initial capital outlay but also ongoing charges for disposable and maintenance items. Thus, the decision of which device to purchase is complex and requires careful evaluation of all of the previously noted variables. Likewise, if one is fortunate enough to have more than one device available, the decision of which lithotriptor to employ requires a similar decision based on sound surgical judgment.

Retrograde ureteropyeloscopy for lower pole caliceal calculi

PURPOSE

Contemporary treatment of lower pole renal calculi includes extracorporeal shock wave lithotripsy, percutaneous nephrostolithotomy and retrograde ureteropyeloscopy. Success rates for shock wave lithotripsy are reduced in this setting, especially for stones greater than 1 cm. and/or in patients with anatomical variants. Percutaneous treatment, although effective, subjects the patient to increased morbidity. We studied the safety and efficacy of retrograde ureteroscopic treatment of lower pole intrarenal calculi.

MATERIALS AND METHODS

We evaluated 90 stone burdens localized to the lower pole and treated with a small diameter, actively deflectable, flexible ureteropyeloscope and a 200 micron holmium laser fiber. Stone burdens were classified as group 1--10 or less, group 2--11 to 20 and group 3--greater than 20 mm. in largest diameter. Patients with calculi less than 2.5 cm. were treated as outpatients unless concurrent medical conditions required hospitalization. Larger stones and partial staghorn calculi (group 3) frequently required 2-stage endoscopic procedures with retrograde intrarenal irrigation for 36 hours to clear debris. An acceptable immediate surgical outcome was defined as complete fragmentation reducing the stone burden to dust and 2 mm. or less fragments. Success was defined as clear imaging (that is stone-free) on renal sonography with minimum 3-month followup. Extreme anatomical variants, including a long infundibulum, acute infundibulopelvic angle and a dilated collecting system, were noted and correlated with surgical failures.

RESULTS

Endoscopic access and complete stone fragmentation were achieved in 94, 95 and 45% of groups 1, 2 and 3, respectively. After a second treatment the success rate increased to 82% in group 3, with an overall rate of 91%. Of the 19 surgical failures 8 were secondary to inability to access the lower pole and 11 were secondary to inability to render the patient stone-free. In 2 of the 19 cases infundibular strictures hindered ureteroscopic access. In addition, of the anatomical variants a long lower pole infundibulum was the most statistically significant predictor of failure. Mean operative time ranged from 38 minutes for small to 126 for the largest calculi. There were no major complications. Overall stone-free rates with minimum 3-month followup were 82, 71 and 65% in groups 1, 2 and 3, respectively, and 88, 77 and 81%, respectively, in patients with an acceptable initial surgical outcome (that is excluding those with access failures from analysis).

CONCLUSIONS

Retrograde ureteropyeloscopy is a safe and effective surgical treatment for lower pole intrarenal calculi.

Management of upper urinary tract calculi with ureteroscopic techniques

OBJECTIVES

To evaluate our experience in treating 155 patients with upper urinary tract calculi ureteroscopically. The treatment of urinary calculi has remained the most frequent application of ureteroscopy. Miniaturization of semirigid and flexible ureteroscopes has permitted easier access to calculi throughout the urinary tract.

METHODS

Ureteroscopic stone treatment was attempted in 155 patients with upper urinary tract calculi between November 1995 and March 1997. Fifty-nine (38.1%) patients had renal calculi, 82 (52.9%) ureteral, and 14 (9%) had both renal and ureteral calculi. Both semirigid and flexible ureteroscopes were used for treatment (rigid alone in 21 [13.5%], flexible in 64 [41.3%], and both rigid and flexible in 70 [45.2%] patients). Lithotripsy was required in 122 (79%) of the patients. The holmium:yttrium-aluminum-garnet laser was used in 113 (92.6%) of these patients.

RESULTS

All patients with ureteral calculi (29 proximal, 19 mid, and 34 distal) were successfully cleared after one endoscopic procedure except for 1 patient with a proximal ureteral calculus who had a 4-mm residual fragment in the kidney. Of the 59 patients with renal calculi, 47 (79.7%) were totally clear of stones 1 month after treatment. The remaining 12 (20.3%) patients had evidence of residual calculi 3 to 4 mm or less in diameter. In patients with combined renal and ureteral calculi, 1 1 of 14 (78.6%) were rendered stone free. The remaining 3 (21.4%) patients had evidence of residual calculi 4 mm in diameter. Overall, 95% of the patients were treated in an outpatient setting. Morbidity was low, with no evidence of stricture.

CONCLUSIONS

Ureteroscopy and laser lithotripsy in experienced hands are a safe and reliable method for the treatment of ureteral and even intrarenal calculi.

Ureteroscopic lithoclast lithotripsy: a cost-effective option

Seventy-four consecutive cases of ureteral stones listed for ureteroscopic lithotripsy were studied prospectively. In all cases, the Wolf 7.5F or 9F ureteroscope was used in conjunction with the Swiss Lithoclast system. Dormia baskets were employed on four occasions to prevent forward propulsion of fragments. Ureteroscopic access to the stones was successful in 70 patients (95%). Lithoclast lithotripsy was successfully applied in 68 patients (92%), with complete fragmentation noted in 62 patients (91%), one requiring two sessions. The 6-week stone-free rate was 96% for these patients. Five patients with partial fragmentation had successful adjuvant SWL. The overall successful fragmentation rate was thus 84% (62 of 74) and 91% (67 of 74) in combination with adjuvant SWL. Cost analysis indicated a three-fold advantage for the Lithoclast over Candela lasertripsy. Ureteroscopic Lithoclast lithotripsy is a cost-effective treatment modality for ureteral stones.

Lower-pole caliceal stone clearance after shockwave lithotripsy, percutaneous nephrolithotomy, and flexible ureteroscopy: impact of radiographic spatial anatomy

Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP <70 degrees, an IL >3 cm, or an IW < or =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.

The holmium laser in urology

OBJECTIVE

To review the physics related to the holmium laser, its laser-tissue interactions, and its application to the treatment of urological diseases.

SUMMARY AND BACKGROUND DATA

The holmium: YAG laser is a solid-state, pulsed laser that emits light at 2100 nm. It combines the qualities of the carbon dioxide and neodymium:YAG lasers providing both tissue cutting and coagulation in a single device. Since the holmium wavelength can be transmitted down optical fibers, it is especially suited for endoscopic surgery.

METHODS

The authors provide a review of the literature as it relates to the holmium laser and its application to urology.

RESULTS

The holmium wavelength is strongly absorbed by water. Tissue ablation occurs superficially, providing for precise incision with a thermal injury zone ranging from 0.5 to 1.0 mm. This level of coagulation is sufficient for adequate hemostasis. The most common urologic applications of the holmium laser that have been reported include incision of urethral and ureteral strictures; ablation of superficial transitional cell carcinoma; bladder neck incision and prostate resection; and lithotripsy of urinary calculi.

CONCLUSIONS

The holmium: YAG laser is a multi-purpose, multi-specialty surgical laser. It has been shown to be safe and effective for multiple soft tissue applications and stone fragmentation. Its utilization in urology is anticipated to increase with time as a result of these features.

Safety and efficacy of the Alexandrite laser for the treatment of renal and ureteral calculi

OBJECTIVES

To assess the safety and efficacy of the Alexandrite laser for intracorporeal lithotripsy of renal and ureteral stones in conjunction with ureterorenoscopy or percutaneous nephrostolithotomy.

METHODS

We retrospectively analyzed the records of 137 patients with 169 calculi in 143 renoureteral units who were treated with the Alexandrite laser via a retrograde (91.5%) or antegrade (8.5%) endoscopic approach.

RESULTS

Adequate intraoperative fragmentation of the stone was observed in 88.8% of the cases. No intraoperative complications were attributable to the laser. At a mean follow-up of 34 days, the overall stone-free rate was 74.4%. The stone-free rate for ureteral stones (n = 115) was 80%, whereas the stone-free rate for renal stones (n = 22) was only 44%. In the best subgroup of ureteral stones (10 mm or less in the distal ureter), the stone-free rate was 97.4%.

CONCLUSIONS

The Alexandrite laser is a safe modality for intracorporeal lithotripsy and is highly effective for ureteral stones less than 10 mm in size.

Efficacy and cost-effectiveness of extracorporeal shock wave lithotripsy for solitary lower pole renal calculi

PURPOSE

We determined the efficacy of extracorporeal shock wave lithotripsy monotherapy and compared its cost-effectiveness with percutaneous nephrolithotomy for the management of lower pole renal calculi.

MATERIALS AND METHODS

The efficacy (stone-free rates at 3-months posttreatment) of shock wave lithotripsy with the modified Dornier HM3* machine was determined retrospectively in 114 patients with solitary lower pole renal calculi. Using cost data available from patient billing charges and efficacy data from the literature, the cost-effectiveness for percutaneous nephrolithotomy and shock wave lithotripsy as primary therapy was evaluated. To make this cost-effectiveness comparison, we developed a decision analysis model in which a patient in whom primary therapy failed was rendered stone-free with a secondary percutaneous nephrolithotomy procedure.

RESULTS

The stone-free rates of solitary lower pole stones with a size range of less than 10, 11 to 20 and greater than 20 mm. were 76, 74 and 33%, respectively, with a single shock wave lithotripsy treatment. Based on average treatment costs for shock wave lithotripsy and percutaneous nephrolithotomy, the model results show that for stone sizes less than 2 cm. primary lithotripsy therapy followed by nephrolithotomy for failed cases is the least costly approach. For stone sizes greater than 2 cm. primary percutaneous nephrolithotomy may be more cost-effective.

CONCLUSIONS

Whereas shock wave lithotripsy with the Dornier HM3 should be considered the initial treatment choice for most lower pole stones less than 2 cm., primary percutaneous nephrolithotomy should be considered for stones larger than 2 cm.

Holmium:YAG lithotripsy yields smaller fragments than lithoclast, pulsed dye laser or electrohydraulic lithotripsy

PURPOSE

The mechanism of lithotripsy differs among electrohydraulic lithotripsy, mechanical lithotripsy, pulsed dye lasers and holmium:YAG lithotripsy. It is postulated that fragment size from each of these lithotrites might also differ. This study tests the hypothesis that holmium:YAG lithotripsy yields the smallest fragments among these lithotrites.

MATERIALS AND METHODS

We tested 3F electrohydraulic lithotripsy, 2 mm. mechanical lithotripsy, 320 microns pulsed dye lasers and 365 microns. holmium:YAG fiber on stones composed of calcium hydrogen phosphate dihydrate, calcium oxalate monohydrate, cystine, magnesium ammonium phosphate and uric acid. Fragments were dessicated and sorted by size. Fragment size distribution was compared among lithotrites for each composition.

RESULTS

Holmium:YAG fragments were significantly smaller on average than fragments from the other lithotrites for all compositions. There were no holmium:YAG fragments greater than 4 mm., whereas there were for the other lithotrites. Holmium:YAG had significantly greater weight of fragments less than 1 mm. compared to the other lithotrites.

CONCLUSIONS

Holmium:YAG yields smaller fragments compared to electrohydraulic lithotripsy, mechanical lithotripsy or pulsed dye lasers. These findings imply that fragments from holmium:YAG lithotripsy are more likely to pass without problem compared to the other lithotrites. Furthermore, the significant difference in fragment size adds evidence that holmium:YAG lithotripsy involves vaporization.

Ureteroscopic management of ureteral calculi: electrohydraulic versus holmium:YAG lithotripsy

PURPOSE

This study compared electrohydraulic and holmium:YAG lithotripsy for ureteral calculi.

MATERIALS AND METHODS

Two cohorts of consecutive patients with ureteral calculi treated with ureteroscopic electrohydraulic or holmium:YAG lithotripsy were retrospectively compared. Electrohydraulic lithotripsy was done using a 1.9F fiber at energy settings between 50 and 100 v. Holmium:YAG lithotripsy was done using a 365 microm. fiber at energy settings of 0.6 to 1.5 J.

RESULTS

A total of 23 and 47 consecutive patients underwent electrohydraulic and holmium:YAG lithotripsy, respectively. For preoperative calculi less than 15 mm. mean stone size plus or minus standard deviation was 9 +/- 3 versus 9 +/- 3 mm. (p = 0.5), mean operative time was 72 +/- 21 versus 102 +/- 38 minutes (p = 0.004), stone-free rate at the end of ureteroscopy was 65 versus 97 (p < 0.01) and 3-month stone-free rate was 94 versus 97% (p = 0.4) for electrohydraulic versus holmium:YAG lithotripsy. For preoperative calculi 15 mm. or greater stone size was 19 +/- 5 versus 19 +/- 4 mm. (p = 0.9), operative time was 159 +/- 61 versus 108 +/- 27 minutes (p = 0.01), stone-free rate at the end of ureteroscopy was 33 versus 87% (p = 0.001) and 3-month stone-free rate was 67 versus 100% (p = 0.02). Complications were not significantly different in either comparison.

CONCLUSIONS

The overall likelihood that a patient would be rendered stone-free at ureteroscopy and 3 months after ureteroscopy favored holmium:YAG over electrohydraulic lithotripsy. For ureteral calculi less than 15 mm. electrohydraulic lithotripsy was more rapid than the holmium:YAG procedure but for ureteral calculi 15 mm. or greater the holmium:YAG technique was more rapid than electrohydraulic lithotripsy. The outcomes differences may have resulted from the different mechanisms of electrohydraulic and holmium:YAG lithotripsy.