Ureteropyeloscopic treatment of ureteral and intrarenal calculi

Management options for lower pole renal calculi

PURPOSE OF REVIEW

The optimal treatment of lower pole renal calculi is controversial. Shock wave lithotripsy, ureteroscopy and percutaneous nephrostolithotomy all constitute viable therapeutic options in select patients.

RECENT FINDINGS

Lower pole stones smaller than 1 cm in diameter can be managed with observation, shock wave lithotripsy or ureteroscopy. Patients electing expectant management should be counseled regarding the potential for stone-related symptom progression and need for future intervention. Shock wave lithotripsy and ureteroscopy have similar stone-free rates, although shock wave lithotripsy may be preferable due to more favorable secondary outcomes. Lower pole stones 1-2 cm in diameter are best managed with percutaneous nephrostolithotomy, although ureteroscopy is an option in select patients, particularly those not considered candidates for percutaneous nephrostolithotomy. Finally, patients with lower pole stones larger than 2 cm are best served with percutaneous nephrostolithotomy, as the morbidity in experienced hands is low and stone-free rates are unequivocally higher than those of other treatment modalities.

SUMMARY

A variety of factors, including patient body habitus, local renal anatomy, cost and patient preference, must be taken into consideration when determining the optimal treatment modality for lower pole renal calculi.

Shock Wave Lithotripsy or Ureteroscopy for the Management of Proximal Ureteral Calculi: An Old Discussion Revisited

PURPOSE

The goal of treating ureteral calculi is to achieve complete stone clearance with minimal patient morbidity. Shock wave lithotripsy and ureteroscopy have become standards of care for ureteral calculi. However, the optimal choice of treatment depends on various factors, including stone size, composition and location, clinical patient factors, equipment availability and surgeon capability. Indications for and outcomes data on shock wave lithotripsy and ureteroscopy for proximal ureteral calculi were reviewed to provide recommendations on the optimal treatment choice for managing symptomatic ureteral calculi.

MATERIALS AND METHODS

A systematic review was performed based on an English literature search using the MEDLINE database between 1997 and 2005. The key words used were proximal ureteral calculi, ureteroscopy and shock wave lithotripsy.

RESULTS

A total of 87 articles were identified, of which 33 were selected for inclusion. Shock wave lithotripsy and ureteroscopy provided an excellent stone-free rate (86% to 90%) for stones less than 10 mm, whereas for larger stones ureteroscopy achieved better outcomes vs shock wave lithotripsy (67% vs 73%). Ureteroscopy was preferred over shock wave lithotripsy in patients with pregnancy or bleeding diathesis.

CONCLUSIONS

Ureteroscopy provides optimal stone clearance in patients with proximal ureteral calculi more than 10 mm. It is also recommended in patients with contraindications for shock wave lithotripsy. In patients with smaller stones (less than 10 mm) shock wave lithotripsy may be considered a reasonable alternative with outcomes similar to those of ureteroscopy.

Treatment Selection and Outcomes: Renal Calculi

This article summarizes the history of how renal stones have been treated over the centuries and reviews current treatments and outcomes for renal stones. The authors provide an algorithm based on available outcome data for shock wave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy.

History of lasers

The developments of laser technology from the cradle of modern physics in 1900 by Planck to its latest medical boundaries is an exciting example of how basic physics finds its way into clinical practice. This article merits the protagonists and their contribution to the steps in this development. The competition between the different research groups finally led to the award of the Nobel Prize to Townes, Basov and Prokhorov in 1964 for the scientific basis on quantum electronics, which led to the construction of oscillators and amplifiers based on the laser-maser principle. Forty-three years after Einstein's first theories Maiman introduced the first ruby laser for commercial use. This marked the key step for the laser application and pioneered fruitful cooperations between basic and clinical science. The pioneers of lasers in clinical urology were Parsons in 1966 with studies in canine bladders and Mulvany 1968 with experiments in calculi fragmentation. The central technological component for the triumphal procession of lasers in urology is the endoscope. Therefore lasers are currently widely used, being the tool of choice in some areas, such as endoscopical lithotriptic stone treatment or endoluminal organ-preserving tumor ablation. Furthermore they show promising treatment alternatives for the treatment of benign prostate hyperplasia.

Clinical outcome of ureteroscopic lithotripsy for 2,129 patients with ureteral stones

The objective of this study was to retrospectively analyze the clinical outcomes of ureteroscopic lithotripsy (USL) performed in patients with ureteral stones, and to investigate the factors associated with therapeutic outcomes. This study included a total of 2,129 patients with ureteral stones who underwent USL between December 1985 and March 2006 in a single institution in Japan. In this series, ultrasonic lithotripsy was primarily performed, and forceps and/or baskets were occasionally used for the removal of stones. Complete removal was defined as total clearance 1 day after the initial USL. The initial stone-free rate following a single treatment with USL was 73.3%. Of 569 patients diagnosed as having fragmentation of residual stones, additional therapy was not performed for 115 with stones likely to pass spontaneously, while the remaining 454 subsequently underwent extracorporeal shock wave lithotripsy. Thereafter, ureterolithotomy or percutaneous nephrolithotripsy was further added in 14. Ureteral perforation occurred in 14 patients, of whom 2 underwent nephrectomy; however, there were no other serious complications that could not be managed by conservative treatment. Whether ureteral stones were completely removed by an initial USL was significantly associated with the history of ureteral stone, severity of clinical symptoms, number of stones, localization of stones and maximal diameter of stones. Furthermore, multivariate analysis identified the severity of clinical symptoms, number of stones, localization of stones and maximal diameter of stones as independent predictors for complete removal of ureteral stones by the initial USL application. These findings suggest that USL could be a safe and effective treatment option for ureteral stones; however, other therapeutic strategies should also be considered in patients with currently identified risk factors associated with treatment failure following a single USL procedure.

Safety And Efficacy of Ureteral Access Sheaths

The ureteral access sheath (UAS) was introduced as a means of passing a flexible ureteroscope. Although the device was initially lauded for its ability to facilitate ureteroscopic access, passage was difficult and risked ureteral injury, and the UAS fell out of favor until the development of a new generation of devices that was easier to insert. The UAS should be advanced under fluoroscopy over a stiff guidewire, and the surgeon should ensure copious hydration of all inner and outer surfaces. Use of the UAS is purported to improve irrigant flow and visibility. The UAS can induce transient ureteral ischemia and promote an acute inflammatory response, but it also prevents potentially harmful elevations in intrarenal pressure. Unequivocal data are not yet available to suggest that UAS use during ureteroscopy protects or harms the upper urinary tract. The UAS also has the potential to improve stone-free rates by allowing passive egress or active retrieval of fragments. A large prospective study is needed to unequivocally determine if UAS use is superior in terms of stone-free rates. Cost studies reported to favor UAS use, although a formal cost-effectiveness analysis has not been performed. Further study is needed before routine use of the UAS can be recommended.

Advanced Ureteroscopy: Wireless and Sheathless

BACKGROUND

The introduction of a new generation of flexible ureteroscopes significantly advanced the therapeutic and diagnostic efficacy of the instrument, allowing greater access to all aspects of the upper urinary tract and facilitating wireless ureteroscopy.

PATIENTS AND METHODS

Four hundred sixty consecutive upper urinary-tract procedures were performed utilizing the 7.5F actively deflectable, flexible ureteroscope. A prospective database of these procedures was maintained. The indications, access technique, complications, success rate of stone treatment, and access to lower-pole calices were evaluated. The accumulated clinical data were compared with a published database of 1000 consecutive flexible ureteroscopies.

RESULTS

A stent was in place or had recently been in place in 108 of the procedures (24%). Of the remaining 352 flexible ureteroscopic procedures, only 11% (52) required any form of ureteral dilation to facilitate ureteral access. Two hundred twenty seven procedures were performed in which no guidewire was required to place the flexible endoscope in the upper urinary tract (i.e., "wireless" ureteroscopy).

CONCLUSION

Wireless no-touch flexible ureteroscopy with the new flexible instruments is a feasible and safe technique for diagnostic and therapeutic procedures in most patients, irrespective of the location of the pathology, including the distal ureter. These ureteroscopes, with their exaggerated deflection, are ushering in a new era of endoscopic treatment of the upper urinary tract. Greater instrument deflectability and control can lead to shorter procedures and fewer treatment failures.

Minimally invasive management of urolithiasis

The management of urolithiasis has radically changed over the last two decades. Open surgery has been almost completely replaced by minimally invasive procedures, mainly extracorporeal shock wave lithotripsy (ESWL) and ureteroscopy (URS). Although these treatment modalities have been proven to be very safe and effective, serious complications can occur. Prompt diagnosis is often essential and may even be lifesaving. Radiologists play an important role in this setting, since many of these complications can be readily diagnosed by imaging. Awareness of the wide spectrum of complications may be crucial in interpreting imaging studies of patients who have undergone one of these procedures. This article reviews the contemporary management of ureteric stones with ESWL and URS and illustrates the radiological findings of complications of these procedures.

Ureterorenoskopie (URS) bei Harnsteinen

Distal ureteral calculi (<5 mm) usually pass the ureter spontaneously. Ureteroscopic lithotripsy of distal ureteral calculi shows high stone-free rates with a low complication rate (4%) and is equal to extracorporeal shock wave lithotripsy (ESWL), while ESWL is the primary choice for proximal ureteric stones. Flexible endoscopes are more difficult to handle and should be used only under fluoroscopic control. They are generally used in combination with the holmium:YAG laser and the flexible Lithoclast in the proximal ureter or the renal collecting system. Overall the complication rate of URS is 9-11% with avulsion of the ureteric urothelium being the most common complication. Ureteral perforation, stricture (<1%), impaction of the instrument in the ureter with consequent ureteral laceration, extravasation of stones, and bleeding in the urogenital tract are complications of URS but are minimal in the hands of a well-trained and skilled surgeon.

The evolution of ureteroscopy: a modern single-institution series

OBJECTIVES

To evaluate a modern ureteroscopy series, including the use of new technological advances, operative procedures, and potential complications, at a single institution and to compare our current experience with our prior published series and the current literature.

MATERIAL AND METHODS

We retrospectively reviewed 1000 consecutive ureteroscopies performed in 961 patients from December 1999 to February 2003 at our institution.

RESULTS

Semirigid and flexible ureteroscopes were used in 60.3% and 37.0% of the cases, respectively. In 2.6% of cases, a combination of both rigid and flexible ureteroscopes was required. The most common indications for ureteroscopy were as follows: stone, 57.9%; diagnostic, 20.6%; and urothelial carcinoma, 12.6%. Of the stones treated, 31.8% were proximal or middle and 59.1% distal. The overall, proximal, and distal stone-free rates were 91.7%, 87.3%, and 94.2%, respectively. Average operative time was 81 minutes (range, 5-280 minutes). Average follow-up was 2.36 months (range, 1-24 months). The overall complication rate was 1.9% (18/961), including a 0.2% (2/961) incidence of ureteral strictures.

CONCLUSION

Current practice trends have shifted to an increased use of flexible ureteroscopes and more frequent ureteroscopic treatment of proximal calculi. Our single treatment stone-free rates are competitive with quoted shock wave lithotripsy success. In addition, there has been a decrease in ureteroscopic-associated complications in our series, with no ureteral avulsions. The improvements in treatment success and decrease in complications may be secondary to advances in ureteroscopic technology.

Handling and prevention of complications in stone basketing

OBJECTIVE

To review the incidence, risk factors, and treatment options of intraoperative and postoperative complications of stone basketing in urology with emphasis on certain principles that must be upheld to prevent those complications.

METHODS

A literature search was performed using the MEDLINE database on stone basketing between 1970 and 2005.

RESULTS

Iatrogenic trauma due to retrieval of a stone is well known but the exact incidence is difficult to ascertain. Rarely, stone basketing can cause major trauma to the ureter, such as avulsion or intussusception, requiring open or laparoscopic intervention for ureteral continuity restoration. Mucosal abrasion, ureteral perforation, and stricture formation have also been described as complications of stone basketing. Occasionally, the engaged or broken basket can provoke anxiety even for experienced urologists. Factors that increase the risk of complications, strategies for repair, and techniques for prevention are discussed extensively.

CONCLUSION

Infrequent, surgical misadventures during stone basketing can occur and must be treated appropriately. Careful attention to instrument selection and surgical techniques and awareness of risk factors and type and site of potential injury are essential to reduce these complications.

Complications of ureteroscopy

Ureteroscopy has undergone a dramatic evolution over the last two decades. Although ureteroscopic injury is the most common cause of ureteral trauma because of the large number of ureteroscopic procedures performed, improvements in instrumentation and technique have resulted in a reduced incidence of serious complications. Despite significant technologic advances, however, surgical misadventures still occur, some of which have lasting consequences. Careful attention to instrument selection and surgical technique are critical to reduce untoward events related to ureteroscopy. As such, adverse sequelae associated with ureteroscopy should be related to the underlying pathology itself rather than to the treatment.

Exaggerated primary endoscope deflection: initial clinical experience with prototype flexible ureteroscopes

OBJECTIVE

To increase the clinical usefulness of the actively deflectable flexible ureteroscope by making sequential changes in design and then using these prototypes clinically; and to develop a clinical series using the optimum prototype and contrast it with an extensive database of patients treated with the traditional flexible ureteroscope.

METHODS

A series of prototypic flexible ureteroscopes was developed and used clinically. The active deflection of the prototype ureteroscope was evaluated with and with no accessories in the working channel, and compared with a standard 7.5 F ureteroscope. Clinical data were then accrued and compared with a previously published database.

RESULTS

The progression of prototypes led to a final version which incorporated > 300 degrees primary active deflection, shaft miniaturization (8.4 F) and an increase in endoscope shaft stiffness. The prototype flexible ureteroscope had significantly greater active deflection than the standard ureteroscope, especially when working channel accessories were used. In all, 115 endoscopic procedures were carried out, the indications for which included endoscopic lithotripsy for distal calculi (51), treatment of upper tract urothelial carcinoma (27), diagnostic endoscopy (26) and retrograde endopyelotomy (three). No guidewire was required to place the flexible ureteroscope into the upper urinary tract in 27% of patients. Active intramural dilatation for access was only required in 3% of the procedures. All lower pole calyces were accessed with this instrument.

CONCLUSIONS

Adding exaggerated deflection is a timely advance in flexible ureteropyeloscopy. This and the other changes in design facilitated complex retrograde endoscopic procedures and increased the therapeutic potential of the instrument.

Evaluation of the patient with flank pain and possible ureteral calculus

Flank pain due to urolithiasis is a common problem in patients presenting to emergency departments. Radiology plays a vital role in the work-up of these patients. Many modalities can be used, including ultrasonography, nuclear medicine, and the traditionally used techniques of intravenous urography and conventional radiography. The development of nonenhanced computed tomography (CT) (single- or multi-detector row helical) has provided a means to enable detection and characterization of urolithiasis with unprecedented sensitivity, specificity, and accuracy while yielding important information for treatment planning, including the size and location of calculi. This technique can also help detect causes for flank pain outside the genitourinary tract. However, close attention must be paid to all aspects of the CT study to prevent misdiagnoses.

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.

Urinary tract stones--Part II: current status of treatment

The majority of renal and ureteric stones are now managed by minimally invasive techniques, for example nephrostomy, ureteral stents, extracorporeal shockwave lithotripsy or percutaneous nephrolithotomy. A multi-disciplinary approach is necessary, and this review examines the status of modern stone therapy and the contribution of the radiology department.

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.

Surgical management of urolithiasis

The surgical management of urinary calculus disease has changed dramatically in the past two decades. Minimally invasive options have made open stone surgery nearly obsolete. The development of shock wave lithotripsy, percutaneous nephrostolithotomy techniques and intracorporeal lithotripsy devices has conferred unprecedented management tools for upper tract stones. Moreover, transfusion rates, hospital costs, and convalescence periods have been markedly reduced when compared to open surgery. Likewise, the advent of fiberoptic technology has resulted in miniaturization of ureteroscopes making access to the entire collecting system possible from either a retrograde or antegrade approach. With experience, successful stone retrieval has occurred in upwards of 90% of cases, again with minimal complications. The subspecialty of Endourology has emerged over the past 20 years and significantly changed the management of urinary tract calculi within this short period of time. Further advancements in shock wave and laser technology, training modules and the development of more durable endoscopes may prove beneficial in providing even better stone treatments with a reduction in morbidity.

Stones in urinary diversions: update on medical and surgical issues

PURPOSE OF REVIEW

Patients who undergo urinary tract diversion are at an increased risk of urolithiasis for various reasons. The purpose of this article is to provide an up-to-date summary of the progress that has been made in the pathogenesis, diagnosis and treatment of stones in patients with urinary diversions. Finally, we will provide recommendations for follow-up in patients with urinary diversions who develop urinary tract calculi.

RECENT FINDINGS

In contemporary studies, the incidence of urolithiasis in patients with urinary diversion appears to be decreasing. Computed tomography scanning has been shown to be superior to ultrasound in the diagnosis of calculi in such patients. Endourological procedures have become the mainstay of therapy for stones in patients with urinary diversions. Since the introduction of extracorporeal shock wave lithotripsy, percutaneous nephrolithotripsy and ureteroscopy, the need for open surgery has decreased, even in this anatomically unique and surgically challenging patient population.

SUMMARY

Urolithiasis is an established long-term complication of urinary diversion. In recent years, significant advances have been made in the pathogenesis, diagnosis and treatment of such stones. As a result of potential stone-related complications, we recommend lifelong surveillance for all patients with urinary stones and diversions, with medical therapy when indicated, in order to minimize these complications.

New concepts in the treatment of ureteral calculi

The management of patients with ureteral stones remains under debate in several areas. The ability to predict spontaneous passage has improved but remains imprecise, whilst the range of therapeutic options continues to widen. Excellent results can be obtained by both shockwave lithotripsy and ureteroscopic methods, with relatively minimal complications. Routine ureteral stenting is not warranted whichever treatment is chosen. In future, directly comparative studies should be designed to incorporate quality-of-life parameters rather than just stone-free status, to improve our understanding of the effect of treatment decisions on patients.