Ureteroscopy. Development and instrumentation

Current status of flexible ureteroscopy in urology

Retrograde intrarenal surgery (RIRS) is being performed for the surgical management of upper urinary tract pathology. With the development of surgical instruments with improved deflection mechanisms, visuality, and durability, the role of RIRS has expanded to the treatment of urinary calculi located in the upper urinary tract, which compensates for the shortcomings of shock wave lithotripsy and percutaneous nephrolithotomy. RIRS can be considered a conservative treatment of upper urinary tract urothelial cancer (UTUC) or for postoperative surveillance after radical treatment of UTUC under an intensive surveillance program. RIRS has a steep learning curve and various surgical techniques can be used. The choice of instruments during RIRS should be based on increased surgical efficiency, decreased complications, and improved cost-benefit ratio.

Controversies in ureteroscopy: Wire, basket, and sheath

In the last one to two decades, flexible ureteroscopy has rapidly expanded its role in the treatment of urologic stone disease. With the frequent and expanded use of flexible ureteroscopy, other ancillary instruments were developed in order to ease and facilitate this technique, such as ureteral access sheaths (UAS) and a variety of wires and baskets. These developments, along with improved surgeon ureteroscopic competence, have often brought into question the need to implement the “traditional technique” of flexible ureteroscopy. In this review, we discuss a brief history of flexible ureteroscopy, its expanded indications, and the controversy surrounding the use of UAS, wires, and baskets.

Update on flexible ureteroscopy

OBJECTIVE

An update on ureteroscopy with focus on current technology and newer instrumentation is presented.

METHODS

A literature search through Medline-indexed journals as well as personal comments are included in this review. Topics such as new semirigid and flexible ureteroscopes, lasers, ureteral access sheats, wires and stone extraction devices are outlined.

RESULTS

Thanks to the continuous advances of technology and miniaturization of instruments, ureteroscopy is an ever-expanding field. A clear outline of the available instruments and techniques with reference to published results catches the status of this dynamic field.

CONCLUSIONS

Urologists are faced with a host of new products related to ureteroscopy every year. This review serves to identify the most useful and proven advances in the field and helps in selecting the equipment needed for a successful minimally invasive approach to upper urinary tract pathologies.

Third Prize: Contemporary Percutaneous Nephrolithotripsy: 1585 Procedures in 1338 Consecutive Patients

BACKGROUND AND PURPOSE

The approach to urinary-stone disease has changed dramatically over the last three decades with a transition from open surgery to minimally invasive procedures. Percutaneous nephrolithotripsy (PCNL) is a cornerstone of the treatment of kidney and selected upper-ureteral stones and continues to evolve with advances in techniques and instrumentation. The purpose of this study was to assess outcomes and trends prospectively in a large contemporary group of patients undergoing PCNL.

PATIENTS AND METHODS

Between July 1990 and December 2005, all 1338 patients at a single center scheduled for PCNL (N = 1585 procedures) were enrolled. Their mean age was 53 years (range 4-89 years). Data including comorbidities, stone burden, stone location, surgical time, hospital length of stay, rate of secondary procedures, and adverse events were collected prospectively. The primary outcome measures were stone-free rate and complications.

RESULTS

There was a substantial incidence of comorbid medical conditions (48.8%) and anatomic renal abnormalities (25.3%), demonstrating the diverse and challenging patient population in this contemporary series. The overall stone-free rate at 3 to 6 months of follow-up was 94.8%.

CONCLUSIONS

Percutaneous nephrolithotripsy is a highly effective procedure and may be performed in a diverse group of patients with comorbid conditions and renal abnormalities. Improved intracorporeal lithotripters, balloon dilation of the tract, use of flexible instruments, and liberal use of secondary nephroscopy result in excellent stone-free rates with low morbidity.

Retrograde proximal rigid ureteroscopy and pyeloscopy in prepubertal children: safe and effective

PURPOSE

Traditionally, rigid ureteroscopy in adults has been reserved for distal ureteral procedures, due to the risk of injury associated with proximal ureteroscopy. However, the safety of proximal rigid ureteroscopy in prepubertal children is not well established.

MATERIALS AND METHODS

We retrospectively evaluated all prepubertal children (12 years old and younger) who underwent attempted rigid proximal ureteroscopy and pyeloscopy. The indications for ureteroscopy were treatment of ureteral and/or renal pelvic calculi, and evaluation of hematuria. All patients were evaluated postoperatively with renal and bladder ultrasonography and abdominal radiography (if stone was visible before treatment).

RESULTS

A total of 24 consecutive children 3.4 to 12 years old underwent 24 ureteropyeloscopic procedures. Of these children 20 (83%) successfully underwent 20 rigid ureteroscopic and pyeloscopic procedures. However, 4 procedures (17%) were converted from rigid to flexible endoscopy to perform 4 successful ureteropyeloscopies. The indications for ureteroscopy were treatment of ureteral and/or renal pelvic calculi in 22 patients and evaluation of hematuria in 2. Followup was 0.6 to 3.6 years (mean 1.9) for the patients undergoing rigid ureteropyeloscopy. All children with calculi were rendered stone-free based on direct visualization by complete ureteroscopy and pyeloscopy of the affected system. No complications occurred during any of the procedures.

CONCLUSIONS

Proximal rigid ureteroscopy and pyeloscopy can be safely applied toward treatment of proximal ureteral and renal pelvic calculi as well as diagnostic ureteropyeloscopy in prepubertal children. The technique has several advantages compared to flexible ureteroscopy.

Durability of flexible ureteroscopes: a randomized, prospective study

PURPOSE

We performed a randomized, prospective, multi-institutional study evaluating the durability of commercially available flexible ureteroscopes.

MATERIALS AND METHODS

A total of 192 patients were randomized to the use of 7 less than 9Fr flexible ureteroscopes, including the Storz 11274AA and Flex-X, the ACMI DUR-8 and DUR-8 Elite, Wolf models 7330.170 and 7325.172, and the Olympus URF-P3. Information about total and lower pole use time, the number and method of ureteroscope insertion, and they type and duration of accessory instrumentation was recorded. Surgeons were asked to rate the visibility and maneuverability of the instrument on a scale of 0-poor to 10-excellent.

RESULTS

The indication for ureteroscopy was upper tract calculi in 87% of cases. Of ureteroscope insertions 97% were performed through an access sheath. The average of number of cases before repair ranged from 3.25 for the Wolf 7325 to 14.4 for the ACMI DUR-8 Elite. Average ureteroscope operative time was statistically longer for the DUR-8 Elite (494 minutes) than for the Flex-X (p = 0.047), and the Wolf 7325 and 7330 (p = 0.001 and 0.001, respectively). Duration of use before repair for the URF-P3 (373 minutes) was statistically longer than for the Wolf 7325 and 7330 (p = 0.016 and 0.017, respectively). Minutes of use with an instrument in the working channel were significantly more with the DUR-8 Elite and the URF-P3 than the Wolf 7330 (p = 0.017 and 0.008) and 7325 (p = 0.012 and 0.005, respectively). The ureteroscope that experienced the greatest average duration of lower pole use was the URF-P3, while the shortest was the Wolf 7325 (103 vs 20 minutes, p = 0.005). Average minutes of laser use before breakage was significantly longer for the DUR-8 Elite than for the Wolf 7325 (110 vs 21 minutes, p = 0.021) and 7330 (24 minutes, p = 0.025).

CONCLUSIONS

Currently available less than 9Fr flexible ureteroscopes remain fragile instruments. The DUR-8 Elite and Olympus URF-P3 proved to be the most durable devices.

Ureteroscopic Resection of Upper-Tract Transitional-Cell Carcinoma

Technological advances have increased the applicability of endoscopic treatment for upper-tract transitional-cell carcinoma (TCC). Percutaneous and ureteroscopic tumor resection have become reasonable treatment options for patients with anatomically or functionally solitary kidneys, bilateral upper-tract tumors, significant renal insufficiency, or comorbid disease that would preclude standard open surgery. This approach also is being used increasingly on those with a normal contralateral kidney in whom nephroureterectomy and en bloc removal of the ipsilateral ureteral orifice and surrounding bladder cuff is considered the standard therapy. This paper reviews the current role of ureteroscopic management of upper-tract TCC.

Physical properties of flexible ureteroscopes: implications for clinical practice

BACKGROUND AND PURPOSE

Physical characteristics may be important in the performance of a flexible ureteroscope. This study evaluated the strength of the shaft and deflection mechanism of several instruments.

MATERIALS AND METHODS

Sequential loads were placed along the axis of downward deflection to measure the stiffness of the shaft and strength of deflection. Bending pressure was defined as the force required to deflect the tip of the ureteroscope 15 degrees from baseline. Buckling pressure was defined as the force that resulted in catastrophic bending (>90 degrees) of the shaft of the ureteroscope. Strength of deflection was defined as the force that resulted in loss of 10 degrees of active deflection.

RESULTS

Bending pressures were lower for the Olympus URF-P3 (6.4 g) and Wolf 7325.172 (6.0 g) ureteroscopes. Similarly, buckling pressures were lower for these two ureteroscopes (9.0 g and 11.6 g, respectively). The Wolf and Storz flexible ureteroscopes had stronger deflection mechanisms than the Olympus URF-P3 and the ACMI DUR-8.

CONCLUSIONS

This study demonstrates significant differences in ureteroscope strength. Higher buckling pressures may facilitate advancement of a ureteroscope over a guidewire but may impede secondary deflection. Lower bending pressures may facilitate passive intrarenal manipulation. Strength of deflection may impact the ability to maintain deflection with an instrument in the working channel.

Ureteroscopic management of upper tract transitional cell carcinoma

The expanding experience with endoscopic techniques for treating upper tract urothelial malignancy demonstrates its safety and efficacy in carefully selected patients. Diagnostic accuracy can be enhanced, and pathologic confirmation of tumor grade and stage is possible. In carefully selected patients who have low-grade and low-stage disease, the results of endourologic management have been encouraging. Patients with an anatomic or functionally solitary kidney, bilateral disease, or significant renal insufficiency can often be considered candidates for endoscopic treatment as the first line of therapy. In the setting of low-grade, low-stage disease in a patient with a normal contralateral kidney, the role of endourologic management remains controversial. Adjuvant topical therapy with mitomycin C or BCG seems to be safe and well tolerated after endoscopic management of upper tract TCC.

The use of rigid ureteroscope in the treatment of ureteral steinstrasse after extracorporeal shockwave lithotripsy of renal calculi: Case report

Introduction Exracorporeal shockwave lithotripsy (ESWL) is the first choice for patients with urolithiasis. Increased use of endoscopic techniques provided increased use of ureteroscopic lithotripsy in the treatment of stones located in distal ureter, as well as ESWL. Rigid ureteroscope is usually used in the management of distal ureter stones, while middle and upper ureter stones should be treated by flexible ureteroscope or ESWL. At Urology Clinic in Novi Sad, ureteroscopy has been used since 1986, and more than 1000 procedures have been preformed with success rate of over 95% (100% when we were able to reach the stone). The aim of this report is to show the destruction of stone along the ureter, using a rigid ureteroscope, shortly after the ESWL treatment of kidney stones. Case report A 46-year-old woman was admitted to the Clinic with "steinstrasse" along the ureter, two weeks following ESWL of kidney stones. Primarily, she underwent ESWL without J-J stenting, at another urologic department. On admission to our Clinic, she complained of pain, nausea, mild temperature. An urgent diagnosis was carried out and left sided "steinstrasse" with hydronephrosis was confirmed by ultrasound, plain X-ray, laboratory findings. Ureteroscopy was performed under spinal anesthesia by rigid ureteroscope and the stone was destroyed along the ureter, even the pyelon was explored at the end of the procedure. The patient was advised to take a lot of fluids with diuretics and 80% of stones were eliminated in the first week after the procedure. At the first control, a month later, the patient was stone free. Conclusion Rigid ureteroscope is a therapeutic option for distal ureteral stones, just as ESWL with comparable and reproducible results. This case confirms the fact that in strictly selected cases, and careful work of skilled urologists, rigid ureteroscope can be used for successful stone destruction in the middle and upper ureter.

Ureteroscopy and holmium:YAG laser lithotripsy: an emerging definitive management strategy for symptomatic ureteral calculi in pregnancy

OBJECTIVES

To review the results of holmium laser lithotripsy in a cohort of patients who presented with symptomatic urolithiasis in pregnancy. Symptomatic urolithiasis in pregnancy that does not respond to conservative measures has traditionally been managed with ureteral stent insertion or percutaneous nephrostomy. Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy using state-of-the-art ureteroscopes represents an emerging strategy for definitive stone management in pregnancy.

METHODS

A retrospective analysis was conducted at two tertiary stone centers from January 1996 to August 2001 to identify pregnant patients who were treated with ureteroscopic holmium laser lithotripsy for symptomatic urolithiasis or encrusted stents. Eight patients with a total of 10 symptomatic ureteral calculi and two encrusted ureteral stents were treated. The mean gestational age at presentation was 22 weeks. The mean stone size was 8.1 mm. The stones were located in the proximal ureter/ureteropelvic junction (n = 3), midureter (n = 1), and distal ureter (n = 6).

RESULTS

Complete stone fragmentation and/or removal of encrusted ureteral stents were achieved in all patients using the holmium:YAG laser. The overall procedural success rate was 91%. The overall stone-free rate was 89%. No obstetric or urologic complications were encountered.

CONCLUSIONS

Ureteroscopy and holmium laser lithotripsy can be performed safely in all stages of pregnancy, providing definitive management of symptomatic ureteral calculi. The procedure can be done with minimal or no fluoroscopy and avoids the undesirable features of stents or nephrostomy tubes.

Ureteroscopic decompression of an unusual uroepithelial cyst using the holmium:YAG laser

We report a case of an unusual uroepithelial cyst arising from a renal calix in an African-American man with sickle cell trait. The lesion was incised and decompressed using a 7.5F flexible ureteroscope in conjunction with the holmium:YAG laser and a 200-microm quartz laser fiber. To our knowledge, endourologic management of this type of lesion has not been described in the literature.

Current urologic applications of digital imaging

One of the most significant developments in imaging technology has been the process of digitalization. By incorporating currently available digital imaging equipment into surgical practice, urologists can be assured of obtaining real-time video images with optimal clarity and detail. In addition, one can efficiently capture and store still images that are crisper and sharper than their analog counterparts. These factors greatly improve the diagnostic capabilities and organization of today's endourologist.

Use of ureteroscopy and holmium:yttrium-aluminum-garnet laser in the treatment of an infundibular stenosis

An infundibular stenosis is defined by a dilated calyx draining through a narrowed infundibulum into a nondistended renal pelvis. We describe the use of ureteroscopy and the holmium:yttrium-aluminum-garnet (YAG) laser to successfully treat an infundibular stenosis in a 27-year-old woman who presented with left flank pain. The holmium:YAG laser is well suited for this application. It can be applied with precise control of the direction and depth of the cut. The retrograde approach avoids the morbidity of a percutaneous nephrostomy and is well suited for treating an anterior infundibular stenosis.

Advances in digital imaging during endoscopic surgery

BACKGROUND AND OBJECTIVE

Digital imaging capabilities have recently been incorporated into a number of video systems. Contrast enhancement when using a rigid or semirigid endoscope improves image definition by seeking out existing transitions in detail. Only the areas of transition are accentuated, whereas areas without detail are unaffected. During flexible endoscopy, fiberoptic bundles create a classic honeycomb appearance. The use of "fiberscope" filters minimizes this appearance by expanding the image of each fiberoptic fiber. We therefore assessed whether new developments in digital video image processing have improved image quality for endoscopic surgery.

MATERIALS AND METHODS

Fifty urologists reviewed a video playback of various endourologic procedures. The type of endoscope was identified, but the urologic surgeon was blinded to the level of enhancement (high or low) or fiberscope filter (A or B) used. Each video clip was scored from 1 to 5 for the following image variables: identification of structure, detail of image, and background noise or interference. All results were averaged and compared using Student's paired t-test.

RESULTS

During rigid endoscopy, the high and low digital enhancement settings were both superior to no enhancement (P < 0.001), and high enhancement was better than low (P < 0.001). With semirigid endoscopic procedures, high and low digital enhancement were comparable but were superior to no enhancement (P < 0.001). Filters A and B were no better than no enhancement. There was a significant improvement noted with the use of filter A or B during flexible ureteroscopy over no enhancement (P < 0.001). In addition, filter A was better than filter B (P < 0.001).

CONCLUSIONS

Digital enhancement settings during video endoscopy significantly improve images from rigid and semirigid endoscopes. The digital fiberscope filter significantly improves images obtained during flexible ureteroscopy. Digital image enhancement capabilities should be strongly considered when upgrading video systems. Digital technology must be further studied to improve clinical video imaging during endoscopic surgery.

Impact of holmium laser settings and fiber diameter on stone fragmentation and endoscope deflection

We compared the impact of various energy settings, frequency, and fiber diameters on the stone fragmentation capabilities of the holmium laser. Stone phantoms, made from plaster of Paris and uniform in weight, were treated with one of two laser fiber sizes: small (200 and 365 microm) and large (550 and 1000 microm). Stones were immersed in water and fragmented for 3 minutes at 0.5, 1.0, or 2.0 J and 5, 10, or 15 Hz. The mean percentage decrease in weight in the two groups was compared using one-way ANOVA. The effect on flexible ureterorenoscope deflection of the small fibers was tested in two different ureterorenoscopes. Raising the energy level when using the small fibers resulted in more weight loss (P < 0.05). Increasing the frequency up to 10 Hz also resulted in a significant increase in weight loss (P < 0.05), yet above 10 Hz, there was no significant additional weight loss noted for either small fiber. There was no significant difference in the weight loss produced by the two fibers unless the energy setting was >1.0 J. Studies with the large fibers demonstrated similar results, with significant increments of weight loss occurring with increased energy (P < 0.05), while nonsignificant differences were seen for the two fiber diameters. Increasing laser frequency up to 15 Hz resulted in a significant increase in weight loss for the large fibers. Loss of ureterorenoscope deflection ranged from 7% to 16% and 18% to 37% for the 200-microm and 365-microm fibers, respectively. Small-diameter fibers, in combination with semirigid or flexible ureteroscopes, should be used to treat upper urinary tract stones. The 365-microm fiber should be utilized for the management of ureteral stones, as minimal endoscopic deflection is required to access these calculi. Because the 200-microm fibers are considerably more expensive, their use should be reserved for fragmentation of intrarenal calculi, where maximum deflection is required during flexible ureterorenoscopy. The ideal energy and frequency settings for the small fibers are <1.0 J and 5 to 10 Hz. Larger fibers can be used for managing bladder or renal calculi, as there is no need for significant fiber deflection. The 550-microm fiber is preferred, as it is comparable in efficacy to the 1000-microm fiber and is less expensive. Energy and frequency can be maximized to 2.0 J and 15 Hz without damage to the fiber, but visibility can be affected by high frequencies. Appropriate fiber selection and energy/frequency settings will allow access to most stones throughout the urinary tract, maximize fiber life, and minimize fiber expense.

Use of ureteroscopy and holmium:YAG laser in patients with bleeding diatheses

OBJECTIVES

To assess the safety and efficacy of ureteroscopy and holmium laser in patients with known bleeding diatheses and upper tract calculi or transitional cell carcinoma (TCC).

METHODS

Eight patients with stone disease and 1 patient with upper tract TCC were treated ureteroscopically with the holmium laser. The mean age was 58.3 years (range 42 to 74). Six patients were receiving Coumadin, with a mean international normalized ratio (INR) of 2.1 (normal INR less than 1.1). Two patients were thrombocytopenic, and 1 had von Willebrand's disease. None of the bleeding diatheses were corrected before surgery. Semirigid or flexible ureteroscopes were used to access the ureter or intrarenal collecting system. The holmium laser was used to fragment calculi or ablate tumor.

RESULTS

Only 1 patient had a postoperative bleeding complication related to the procedure, involving an episode of oliguria secondary to a small ureteral clot. This cleared without surgical intervention. Another patient developed an episode of epistaxis after administration of ketorolac for pain. Six of 7 patients who underwent laser fragmentation for calculi were stone free on follow-up intravenous urogram at 1 month, and no tumor recurrence was noted in the patient with TCC (follow-up of 4 months).

CONCLUSIONS

Ureteroscopy allowed excellent access to all regions of the upper tracts, and holmium laser fragmentation of calculi or ablation of tumor was effective in managing each particular problem. Use of the holmium laser with ureteroscopic access provides a safe and acceptable combination for treating upper tract pathology in patients with uncorrected bleeding diatheses. As a result, these patients can avoid added costs of extended hospital stay and risks associated with transfusions.

Obstructive uropathy

Recent study has increased the understanding of the physiological processes occurring in obstructive uropathy, in particular the role played by vasoactive mediators and cellular mechanisms. There is an emphasis on developing effective and less invasive means of detection and treatment of ureteric obstruction, although it remains to be determined how the techniques currently being assessed will impact on clinical practice.