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

Endoscopic surgery for renal calculi

PURPOSE OF REVIEW

Endoscopic surgery plays an important role in the treatment of renal calculi, especially for the more complex cases. Recent advancements have improved the efficacy of procedures, and increasing surgeon experience is associated with low complication rates. This article will review recent literature pertinent to endoscopic surgery for renal calculi.

RECENT FINDINGS

Endoscopic renal calculus removal is associated with up to >90% calculus clearance rates. This is true for both retrograde and percutaneous approaches. The added utility of flexible instrumentation and holmium laser therapy have contributed greatly to improving surgical success. With increased experience in endoscopic techniques, major complications occur in approximately 1% of patients. Most procedures are performed on an outpatient (retrograde) basis or a <23 h inpatient (percutaneous) basis.

SUMMARY

Endoscopic surgery is safe, and the most efficacious therapy with low morbidity for renal calculi.

Percutaneous nephrolithotomy: an update

PURPOSE OF REVIEW

Percutaneous nephrolithotomy has undergone an evolution in technique and in equipment since its introduction in the late 1970s. This evolution continues today and is evidenced by the numerous publications about the technique. This review summarizes some of the important articles over the past year.

RECENT FINDINGS

Although ureteroscopy and shock wave lithotripsy predominate in the treatment of urolithiasis, percutaneous nephrolithotomy continues to play an important role. Percutaneous nephrolithotomy is advantageous as it causes minimal renal injury and maximizes stone clearance, especially in patients with complex stone disease. Although nephrostomy drainage tubes have always been placed after percutaneous nephrolithotomy, there may be specific indications for tubeless percutaneous nephrolithotomy.

SUMMARY

Percutaneous nephrolithotomy continues to be an important part of the urologist's armamentarium. Recent studies have redefined the role of percutaneous nephrolithotomy and future studies will further delineate the importance of this procedure in the treatment of urolithiasis.

Stone clearance in lower pole nephrolithiasis after extra corporeal shock wave lithotripsy - the controversy continues

BACKGROUND

To determine factors influencing the clearance of fragments after extra-corporeal shock wave lithotripsy (ESWL) for lower pole calyceal (LPC) stones.

METHODS

In the period between July 1998 and Oct 2001, 100 patients with isolated lower polar calyceal calculi <or= 20 mm, in patients aged >or= 14 years, were included in the study. Intravenous urograms (IVU) were reviewed to define the LPC anatomy (width of the infundibulum and pelvicalyceal angle). Study end points i.e. stone free status; number of shock waves used and number of sessions were correlated with variables like LPC anatomy, body mass index and stone size.

RESULTS

At three months follow up the clearance for stone size <or= 10 mm, 11-15 mm and 16-20 mm were 95, 96 and 90% respectively. Patients with acute LPC (<90 degrees ) and obtuse angle (>90 degrees ) had stone clearance of 94 and 100% respectively. For the infundibular width of < 4 mm, the stone clearance was 93% were as for > 4 mm, it was 100%. For body mass index (BMI) less than and > 30 kg/m2, the stone clearance was 92 and 95% respectively.

CONCLUSIONS

There is a trend towards more ESWL sessions and shock wave requirement in patients with acute pelvi-calyceal angle and narrow infundibulum but it is not statistically significant. Size (<or= 20 mm) and BMI has no relation with stone clearance. With modern lithotripter, stones up to 20 mm could primarily be treated by ESWL, irrespective of an un-favorable lower polar calyceal anatomy and body habitus.

Does size and site matter for renal stones up to 30-mm in size in children treated by extracorporeal lithotripsy?

OBJECTIVES

To determine the safety and efficacy of extracorporeal shock wave lithotripsy (ESWL) in the treatment of pediatric nephrolithiasis and to analyze the impact of renal stone size and location on stone clearance.

METHODS

This was a retrospective case series of pediatric patients (14 years or younger) undergoing lithotripsy using a Dornier MPL 9000 echo-guided lithotriptor. Patients were identified using an international coding and indexing system (9th edition) and ESWL registry. One hundred five patients were treated from January 1990 to December 2001. Stone clearance was assessed at 1 and 3 months. A stone-free state was defined as no radiologic evidence of stone or fragments 3 mm or less. Treatment failure was analyzed to find any correlation with stone size and site.

RESULTS

The overall stone-free rate was 95%. The treatment failed in 5 patients, who subsequently required ancillary procedures. Three patients received one session of ESWL, after which they were lost to treatment and were not analyzed further. Four of the five patients with treatment failure had a double-J stent; the stones were located in the lower pole calix in 2, renal pelvis and lower pole calix in 1, and at the ureteropelvic junction in 2 patients. The mean stone size in the treatment failure group was 15.88 mm compared with 14 mm in the stone-free group. The complication rate was 8%, but only 3 patients required admission.

CONCLUSIONS

ESWL is highly effective for pediatric renal stones, with minimal morbidity. Stone clearance is not adversely affected by a stone size up to 30 mm; however, lower pole caliceal stones and stones impacted at the ureteropelvic junction have relatively poorer clearance. Eighty percent of patients who failed to clear their stones had a double-J stent.

Is lower pole caliceal anatomy predictive of extracorporeal shock wave lithotripsy success for primary lower pole kidney stones?

PURPOSE

The management of lower pole kidney stones is controversial. We examined whether lower pole caliceal anatomy could predict the success of extracorporeal shock wave lithotripsy of primary lower pole kidney stones 20 mm. or less.

MATERIALS AND METHODS

From December 1997 to June 2001, 246 adults with a single, 20 mm. or less radiopaque lower pole renal stone were treated with the Doli 50 lithotriptor (Dornier Medical Systems, Marietta, Georgia) while under general anesthesia. Of the 246 patients 190 (77%) had excretory urography available for review. Lower pole infundibular length and width, lower pole infundibulopelvic angle and caliceal-pelvic height were measurable on 161 (85%), 129 (68%), 128 (67%) and 163 (86%) excretory urograms, respectively. Extracorporeal shock wave lithotripsy was considered a failure if residual stone fragments remained after 1 month, or an auxiliary procedure or re-treatment was required. RESULTS The overall stone-free rate was 78% (32 of 41) for stones 5 mm. or less, 73% (98 of 135) for stones 6 to 10 mm., 43% (22 of 51) for stones 11 to 15 mm. and 30% (7 of 19) for stones 16 to 20 mm. in maximum linear dimension. The stone-free rates grouped according to stone surface area were 76% (48 of 63 stones) for stone surface area 25 mm.2 or less, 69% (97 of 141) for 26 to 100 mm.2 and 33% (14 of 42) for 101 to 400 mm.2. Caliceal anatomy was not predictive of success even with stones grouped as 10 or less or 11 to 20 mm. Grouping patients with favorable (lower pole infundibulopelvic angle 70 degrees or greater, lower pole infundibular length 30 mm. or less and lower pole infundibular width greater than 5 mm.) versus unfavorable (70 degrees or less, greater than 30 mm. and 5 mm. or less, respectively) anatomy was also not predictive of success.

CONCLUSIONS

On the Doli 50 machine stone size rather than caliceal anatomy is predictive of treatment outcome. Initial treatment failures with this machine should be managed by alternative endoscopic procedures if necessary rather than by repeat shock wave lithotripsy.

Urinary calculi in aviation pilots: what is the best therapeutic approach?

PURPOSE

We reviewed treatment outcomes in a series of aviation pilots treated in the era of modern surgical techniques and provide recommendations regarding treatment in this unique group.

MATERIALS AND METHODS

We retrospectively analyzed the records of all aviation pilots surgically treated for urinary calculi at our 4 tertiary stone centers from January 1988 to June 2000. Preoperative data and postoperative results were evaluated. Primary outcome measures included stone-free status after initial therapy, time lost from work and overall stone-free rates. Secondary outcome measures included the need for secondary procedures and complications.

RESULTS

Of the 36 patients 17 had renal and 19 had ureteral stones. In 4 patients the stones passed spontaneously, while 17 were initially treated with extracorporeal shock wave lithotripsy (ESWL) (Dornier Medical Systems, Marietta, Georgia), 9 were initially treated with ureteroscopy and 6 were treated with percutaneous nephrolithotripsy. There was 1 complication. The stone-free rate for ESWL, percutaneous nephrolithotripsy and ureteroscopy after initial therapy was 35%, 100% and 100%, respectively. All patients were rendered stone-free after secondary therapy. Mean time lost from work for ESWL, percutaneous nephrolithotripsy and ureteroscopy was 4.7, 2.6 and 1.6 weeks, respectively.

CONCLUSIONS

Aviation pilots with surgical urolithiasis are best treated with an initial endoscopic procedure. Stone-free rates can be maximized, while time lost from work can be minimized when an endoscopic approach is used initially. All pilots with urolithiasis should undergo mandatory metabolic evaluations to institute medical therapy when indicated.

Experimental studies and first clinical experience with a new Lithoclast and ultrasound combination for lithotripsy

OBJECTIVES

A new lithotriptor for intracorporeal lithotripsy was developed combining the two most effective lithotriptors. A combination of the mechanically driven Lithoclast Master and a new ultrasonic device was constructed. Efficacy was tested in standardized model stones and in patient treatment.

MATERIAL

The new lithotriptor is composed of a Lithoclast Master and an ultrasonic device (EMS, Nyon, Switzerland). The 1.0 mm Lithoclast probe is advanced off-center through the hollow 3.3 mm ultrasonic probe and protrudes about 1 mm. Five different artificial stones of defined hardness and density were used as model stones for disintegration. Time until first fragmentation and complete fragmentation (particles smaller than 2.2 mm to fit through the ultrasonic probe), percent disintegration after 1 min and time until 50% disintegration were determined for the new device as well as lithoclast and ultrasound alone. A total of 68 patients were treated by percutaneous nephrolitholapaxy (PNL) with the new device from February 1999 to August 2001. Lithotripsy was performed after fluoroscopically guided puncture of the lower calix and dilatation of the nephrostomy tract with coaxial bougies. Thirty-five patients had complete and 33 patients partial staghorn calculi.

RESULTS

First fragmentation was reached 25-200 times faster with the combination as with either mode alone. Disintegrated stone mass after 1 min was 1.5-4 times larger in combined lithotripsy and 50% disintegration time 30-50% shorter. Clinically, complete stone free rate (KUB and ultrasound) was 66% after the first PNL. Sixteen out of 68 patients had a second look PNL with an overall stone free rate of 89.7% by dismission. Stone composition was calcium-oxalate-monohydrate in 13%, Ca-ox-monohydrate/uric acid in 35%, apatite in 20% and cystine in 11%.

CONCLUSION

In in vitro experiments and clinically the new lithotriptor provides easy handling and high effectivity in fragmentation of all stones regardless of their composition.

Update on shock wave lithotripsy technology

PURPOSE OF REVIEW

Since the first patient was successfully treated with extracorporeal shock wave lithotripsy in 1980, its rapid acceptance and widespread use have championed this form of stone therapy as the treatment of choice for the majority of renal and ureteral calculi. Worldwide clinical series have documented the efficacy and safety of shock wave lithotripsy.

RECENT FINDINGS

Shock wave lithotripters have undergone modifications of the source for generation of shock waves, focusing, and even localization techniques since the introduction of the original Dornier HM3 lithotripter. Yet the basic concepts remain the same: to produce an acoustic wave that can be focused at a specific location for stone fragmentation. Safety and efficacy of the different generations of lithotripters is well documented. Indications and utilization of shock wave lithotripsy have expanded, with clinical efficacy approaching or exceeding that of other modalities of minimally invasive surgery. Complications, however, can arise as a result of shock wave therapy.

SUMMARY

This review provides an update of the latest shock wave technology, reviewing the clinical indications and efficacy of treatment and discussing the potential adverse events associated with shock wave lithotripsy.

Expanding role of ureteroscopy and laser lithotripsy for treatment of proximal ureteral and intrarenal calculi

PURPOSE OF REVIEW

Ureteroscopy has assumed an expanded and important role in the treatment of proximal ureteral and intrarenal calculi with the development of new endoscopes, more effective grasping devices, and the holmium laser lithotriptor.

RECENT FINDINGS

The success rate for treating proximal ureteral stones with small rigid and flexible ureteroscopes and the holmium laser is well over 90%. Lower pole renal calculi can also be treated with a success rate of approximately 80%, which surpasses that of shock wave lithotripsy. Selected stones that are over 2 cm in diameter, along with branched stones, can also be treated successfully with ureteroscopy.

SUMMARY

Ureteroscopy is the most successful technique for the treatment of ureteral calculi (success rates >90%) and is an optional treatment for many renal calculi.

Is there a role for prophylactic shock wave lithotripsy for asymptomatic calyceal stones?

PURPOSE OF REVIEW

The tolerability of extracorporeal shock wave lithotripsy has led to an increase in the treatment of small, asymptomatic renal calculi, yet we know very little about the natural history of such stones or about the long-term effects of this treatment. The efficacy of extracorporeal shock wave lithotripsy has been called into question, especially for lower pole stones. Several recent clinical studies have addressed these issues as well as the natural history of residual stone fragments following extracorporeal shock wave lithotripsy.

RECENT FINDINGS

Preliminary results of a randomized controlled trial show that prophylactic extracorporeal shock wave lithotripsy for small, asymptomatic renal calyceal stones does not appear to offer any advantage to patients in terms of stone-free rates, quality of life, renal function, symptoms, or hospital admissions, nor does it appear to affect blood pressure. However, a policy of observation is associated with a greater risk of requiring more invasive procedures. Reports regarding the incidence of hypertension following extracorporeal shock wave lithotripsy are conflicting, as are reports regarding anatomical factors affecting the clearance of lower pole stones. Percutaneous removal appears to be superior to extracorporeal shock wave lithotripsy for the treatment of lower pole stones.

SUMMARY

Extracorporeal shock wave lithotripsy does not appear to improve the clinical outcome of patients with small, asymptomatic calyceal calculi. Longer follow-up is required to assess the validity of the preliminary findings and may shed light on the long-term effects of this technique on blood pressure and stone growth/recurrence. Anatomical factors affecting the clearance of lower pole stones require standardization and further study. Further in-vitro studies are required to study the kinetics of stone growth and the effects of urine composition, flow rate, and macromolecular components.