Ureteroscopes: flexible, rigid, and semirigid

Effects of administration of local aminophylline on patients undergoing ureteroscopic lithotripsy

INTRODUCTION

The presence of ureteral stones can cause pain, infections of urinary tract and hydronephrosis, resulting in the loss of renal function. For two decades, Ureteroscopy and laser stone fragmentation (URSL) attained a big rise and is the first line management for large ureteric stones and renal stones up to 2 cm. The present study was conducted to assess the success rate of ureteroscopic lithotripsy in treatment of ureteric calculus after local administration of aminophylline.

MATERIALS AND METHODS

100 patients having ureteric calculi <20 mm in size, aged 20-60 years were included in the study and randomly divided into Group A (n = 50) with administration of local aminophylline and Group B (n = 50) with administration of saline infusion. Ureteroscopy was performed after 5 min of administration of the solution. URSL was done using pneumatic lithoclast and/or laser. Various parameters like duration of procedure, ease of ureteral access, requirement of DJ Stent and need of further operative interventions were compared between case and control groups. The data was collected and then subjected to statistical analysis using IBM SPSS 20.0 version at significance level of p < 0.05.

RESULTS

The mean age of study subjects having ureteral stones was found to be between 31 and 40 years of age with males being more affected. We observed less mean duration of surgery, higher success rate, easy ureteral access (p-value < 0.05) with aminophylline use than control group. The need of ureteral stent and Auxiliary procedures was significantly higher in the control than in the case group (38%).

CONCLUSION

The use of aminophylline has been found to be highly useful and effective in reducing the need of stents and secondary surgery, decreased pain, and increased success rate. Thus, the use of aminophylline is recommended during URSL procedure for the successful management of ureteral calculi.

Use of 99m Tc-DTPA Scintigraphy in Evaluation of Ureteral Laceration Due to Transurethral Lithotripsy in a Patient with Nephrolithiasis

Transurethral lithotripsy (TUL) procedure via ureteroscopy as an invasive method for nephrolithiasis treatment would lead to urinary tract injuries. In this reported case, the procedure caused severe damage to the left ureter that was detected by ^99m Tc-diethylenetriaminepentaacetic acid ( ^99m Tc-DTPA) scan. Generally, the TUL procedure through the ureter scope is used to manage urinary tract stones. In this case, the TUL was performed on a patient with a history of nephrolithiasis. Following that, she was accompanied with abdominal pain and discomfort, so ^99m Tc-DTPA scintigraphy was performed to evaluate the urinary tract system. The scintigraphy showed a severe damage to the left ureter that finally resulted in autotransplantation. The control ^99m Tc-DTPA scintigraphy performed 3 weeks after revealed no visible urinary leakage. In this case, the ^99m Tc-DTPA scan prevented the patient from dangerous complications. So, ^99m Tc-DTPA scan could be performed after TUL and ureteroscopy to detect probable risks.

Flexible ureteroscopy: technique, tips and tricks

During the last decades, the surgical management of kidney stones benefited of many technological advances and one of them is the development of flexible ureteroscopy (fURS). This tool, ancillary equipment such as graspers and baskets, and lithotripsy technique with Holmium:YAG laser underwent many improvements leading to a widening of its indications with diagnostic and therapeutic management of upper urinary tract pathologies such as urolithiasis and urothelial tumors. The objective of this review is to describe the surgical technique for fURS as well as tips and tricks for the treatment of renal stones.

Semi-rigid ureteroscopy: indications, tips, and tricks

Advances in ureteroscopic technology, alongside broadening treatment options have fuelled the rapid expansion of endourology. Semi-rigid ureteroscopy is a well-known procedure used globally for varying urological conditions, with high success rates. This article aims to provide ‘tips and tricks’ for the semi-rigid ureteroscopy procedure, and the management of commonly encountered pathology such as renal stones, ureteric strictures, and urothelial tumours.

[Evaluation of stone size before flexible ureteroscopy: Which measurement is best?]

PURPOSE

To retrospectively assess the clinical utility in ureteroscopy (URS) planning of radiological parameters as predictor of stone-free status after a single flexible ureteroscopy.

MATERIAL

Sixty-seven patients with renal stones treated by flexible URS were retrospectively evaluated. To assess the clinical utility of radiological parameters, relationships between stone-free (SF) status and stone burden (maximal diameter, calculated area, calculated volume, cumulative diameter, and tridimentionnal volume [V3D]) were analyzed using the area under the receiver operating characteristics curve and logistic regression.

RESULTS

Maximal diameter (AUC=0.75), calculated area (AUC 0.79), calculated volume (AUC=0.79), cumulative diameter (AUC=0.80) and tridimensional volume (AUC=0.82) revealed ability to predict SF status after URS.

CONCLUSION

Stone burden evaluation is critical in predicting SF status after a single URS. Planar and volumetric measurements showed equal ability to predict SF status. V3D is more accurate but diameter measurement remains easier in clinical practice.

LEVEL OF EVIDENCE

4.

Predictive factors for flexible ureterorenoscopy requirement after rigid ureterorenoscopy in cases with renal pelvic stones sized 1 to 2 cm

Purpose

To evaluate the outcomes of rigid ureterorenoscopy (URS) for renal pelvic stones (RPS) sized 1 to 2 cm and to determine the predictive factors for the requirement for flexible URS (F-URS) when rigid URS fails.

Materials and Methods

A total of 88 patients were included into the study. In 48 patients, the RPS were totally fragmented with rigid URS and F-URS was not required (group 1). In 40 patients, rigid URS was not able to access the renal pelvis or fragmentation of the stones was not completed owing to stone position or displacement and F-URS was utilized for retrograde intrarenal surgery (RIRS) (group 2). The predictive factors for F-URS requirement during RIRS for RPS were evaluated. Both groups were compared regarding age, height, sex, body mass index, stone size, stone opacity, hydronephrosis, and previous treatments.

Results

The mean patient age was 48.6±16.5 years and the mean follow-period was 39±11.5 weeks. The overall stone-free rate in the study population was 85% (75 patients). In groups 1 and 2, the overall stone-free rates were 83% (40 patients) and 87% (35 patients), respectively (p>0.05). The independent predictors of requirement for F-URS during RIRS were male gender, patient height, and higher degree of hydronephrosis.

Conclusions

Rigid URS can be utilized in selected patients for the fragmentation of RPS sized 1 to 2 cm with outcomes similar to that of F-URS. In case of failure of rigid URS, F-URS can be performed successfully in this group of patients.

Advances in ureteroscopy

Ureteroscopy (URS) is a procedure which has been constantly evolving since the development of first generation devices 40 years ago. Progress towards smaller and more sophisticated equipment has been particularly rapid in the last decade. We review the significant steps that have been made toward improving outcomes and limiting morbidity with this procedure which is central to the management of urolithiasis and other upper urinary tract pathology.

Retrograde intrarenal surgery in patients with horseshoe kidneys

Retrograde intrarenal surgery (RIRS) in patients with horseshoe kidneys (HSKs) remains poorly studied. The present study aimed to assess clinical success and stone-free rates in HSK patients with renal stones treated with flexible ureteroscopy. RIRS was attempted in 20 patients with 25 renal stones in HSK from December 2008 to January 2012. The patients were evaluated with imaging studies including plain abdominal radiography, intravenous urogram, abdominal ultrasonography or non-contrast tomography scan. Success rate was defined as stone-free or residual fragment less than 4 mm. Pre-operative, operative and postoperative data were retrospectively analyzed. A total of 20 patients were included in the present study (12 males, 8 females). 9 of 25 renal stones (36 %) were located in the lower calyx of the kidney, whereas 7 (28 %) in the middle calyx, 5 (20 %) in the renal pelvis and 4 (16 %) in the upper calyx. The mean stone size was 17.8 ± 4.5 mm. The stone-free rate was 70 % after a single procedure. 6 patients required shock wave lithotripsy and two of these were completely stone-free. Average hospital stay was 1.4 ± 0.7 days. Minor complications as classified by Clavien I or II occurred in 25 %. No major complications (Clavien III-V) occurred in the study group. RIRS is an effective and safe treatment modality for renal stones in patients with HSK. The procedure has minimal morbidity and high success rate.

Ureteroscopic management with laser lithotripsy of renal pelvic stones

BACKGROUND AND PURPOSE

The development of semirigid and flexible ureteroscopes has permitted easier access to calculi throughout the urinary tract. We compared the use of semirigid and flexible ureteroscopy for the management of shockwave lithotripsy-refractory, isolated renal pelvic calculi by evaluating stone-free rates, operating room times, and associated complications.

PATIENTS AND METHODS

Ureteroscopic stone treatment was attempted in 47 patients with isolated renal pelvic stones between November 2008 and December 2010. The procedures were performed under general anesthesia. Semirigid ureteroscopy was routinely performed in all patients. If the stones were accessible in the renal pelvis with the semirigid ureteroscope (S-URS), they were then treated with the holmium:yttrium-aluminum-garnet (Ho:YAG) laser through S-URS under direct vision. If the stones were not accessible, flexible ureteroscopy was then performed. Preoperative, operative, and postoperative data were retrospectively analyzed.

RESULTS

In 25 of 47 patients, renal pelvic stones were accessible with S-URS, and the stones were fragmented with the Ho:YAG laser using S-URS. In the remaining 22 patients, the stones were accessed with the flexible ureteroscope (F-URS), and the fragmentation of stones was performed with the Ho:YAG laser using the F-URS. There were no significant differences in age, body mass index, grade of hydronephrosis, mean stone size, and stone laterality among the two groups. The mean operative times were 71.90 ± 17.90 minutes in the S-URS group and 93.41 ± 18.56 minutes in the F-URS group (P=0.001). The stone-free rates at postoperative day 1 and at the 1 month follow-up were 72% and 76% in the S-URS group and 81.8% and 86.4% in the F-URS group, respectively (P=0.861 and P=0.368). We found no significant differences among groups with regard to stone-free rates, complication rates, and hospital lengths of stay.

CONCLUSIONS

Although it is well known that flexible ureteroscopy permits a detailed caliceal examination and therapeutic interventions, semirigid ureteroscopy is also often another sufficient means of reaching the renal pelvis in selected patients.

A dual-channel flexible ureteroscope: evaluation of deflection, flow, illumination, and optics

BACKGROUND AND PURPOSE

Despite the evolution and progressive improvements of ureteroscopes, problems related to visibility and maneuverability can still hinder the goals of surgical intervention. We evaluate the attributes of a dual-channel flexible ureteroscope compared with a single-channel device and discuss the implications for expanded techniques afforded by this new technology.

MATERIALS AND METHODS

In vitro measurements of active deflection, irrigant flow through the working channel, luminescence, and optical resolution were performed between the single-channel Wolf Viper and the dual-channel Wolf Cobra ureteroscopes. Characteristics were obtained with the working channels both empty and with combinations of a 200 μ holmium aser fiber, 3.0F biopsy forceps, and 1.5F, 2.4F, and 2.8F nitinol basket. Luminescence from each scope was measured using a commercial luminometer. Three blinded physicians rated the optical resolution captured electronically using a standard test image.

RESULTS

The single-channel scope has improved upward deflection both empty and with all but the largest single tools, with an improved range of 4 to 15 degrees. The dual-channel scope has superior downward deflection across all comparisons (average increase of 24.5 degrees) and superior upward deflection with large or multiple instruments in the working channel. Baseline flows through each individual-channel of the dual-channel scope were slower than the larger single-channel ureteroscope. Because flow can be provided through a dedicated port in the dual-channel configuration, however, overall flow, depending on instrumentation, can be up to 37 times faster than the single-channel (range 1.5-37×). Optical resolution and luminescence are comparable between the two scopes.

CONCLUSION

The dual-channel flexible ureteroscope provides similar deflection characteristics to the current single-channel scope. Deflection and flow characteristics are superior, however, when larger or multiple simultaneous instruments are used in the working channel. These benefits may facilitate the development and implementation of novel endoscopic procedures.

In vitro comparison of a disposable flexible ureteroscope and conventional flexible ureteroscopes

PURPOSE

We compared and evaluated the objective characteristics (deflection characteristics, field of view and flow rate) of a disposable flexible ureteroscope and 6 established, commercially available flexible ureteroscopes.

MATERIAL AND METHODS

Six commonly used ureteroscopes, including Olympus URF-P3, Storz(R) 11278AU and 11274AAU, ACMI DUR-8 Elite and DUR-8, and Wolf 7331.001 (Richard Wolf Medical Instruments, Vernon Hills, Illinois), were compared with the recently introduced SemiFlex Scope disposable flexible ureteroscope. Specifications and purchase costs were acquired from each manufacturer. The disposable ureteroscope consisted of a reusable eyepiece and a semiflexible shaft with a 3.3Fr working channel. Active tip deflection was measured with and without the 3Fr basket, the 365 mum laser fiber and the 3Fr forceps. The flow rate and field of view of each scope were evaluated.

RESULTS

Active tip deflection (down/up) was highest in the disposable ureteroscope at 300/265 degrees. Although deflection was decreased by inserting the different endoscopic tools in all ureteroscopes, the disposable ureteroscope had the highest loss in flexion characteristics (35.7% down and 39.3% up). The flow rate, measured at 25 ml per minute in the disposable ureteroscope, was significantly lower than that of other ureteroscopes. The disposable ureteroscope had a 72-degree field of view, comparable to the optical characteristics of the other scopes. Compared to the other 6 flexible ureteroscopes the purchase price of the disposable scope was significantly lower and no further maintenance/repair expenses were required.

CONCLUSIONS

The disposable flexible ureteroscope has acceptable active tip deflection, field of view and flow rate compared to those of other flexible ureteroscopes on the market. Further evaluation of surgical outcomes will help delineate the definitive usefulness of the disposable flexible ureteroscope.

[The future of ESWL]

With the introduction of the Dornier HM3 lithotripter, the successful history of extracorporeal shock wave lithotripsy (ESWL) for noninvasive treatment of urinary stones began about 25 years ago. The development of newer lithotripters has not been able to improve clinical efficacy because the shock wave parameters specifically responsible for stone disintegration or tissue trauma and pain induction have not yet been identified. Actual research in lithotripter technology deals with modification of the focal point. The evolution of endoscopic procedures, ureterorenoscopy, and percutaneous nephrolithotomy took longer but was more successful in terms of clinical efficacy. Nowadays, ESWL or an endoscopic procedure is offered as a reasonable option for most urinary stone cases. Therefore, economic aspects and the surgeon's expertise will become greater factors when a procedure is chosen. ESWL, with or without anaesthesia, will be an inherent part of future treatment modalities for urinary stones.

Digital ureteroscopy: the next step

BACKGROUND

Flexible ureteroscopy is used for diagnosing and treating upper urinary tract diseases. Despite technological advances in making flexible ureteroscopes smaller, they suffer from a grainy image. Therefore, new technology with better resolution is needed.

NEW TECHNOLOGY

The new Invisio DUR-D digital flexible ureteroscope from Gyrus ACMI was tested. The tip houses dual LED-driven light carriers, which obviates the need for an external light source, thus eliminating the risk of drape fires and patient burns. A 1-mm digital camera at the tip eliminates the need for fragile low-resolution fiberoptics and provides superior resolution. Since there are no external cameras or light cables, the DUR-D is much lighter (505 g compared with 1012 g). Laser detection system deactivates the laser to prevent accidental misfiring of the laser within the ureteroscope.

CONCLUSIONS

The latest generation of digital ureteroscopes provides superior resolution and safety. Long term use is needed to test its durability.

[Relevance of hospitals participating in the DRG calculation for the development of the G-DRG system]

Since the G-DRG system was established for remuneration of inpatient treatment, hospitals may offer the cost data of their cases as a database for the calculation of new DRGs. Therefore, the DRGs will be only as good as the cost data offered. These hospitals must be interested in offering perfect data, since this is the only option to optimize the DRG system.

The pathology of jaundice-related renal insufficiency: cholemic nephrosis revisited

The spectrum of jaundice-related nephropathy can range from limited proximal tubulopathy to renal failure. The latter condition was known as cholemic nephrosis in the early literature on this subject. Elevated plasma concentrations of bile salts and bilirubin conjugated or not, putatively mediate the nephrotoxicity. A functional derangement of renal tubule cells is considered to underlie the nephropathy, but published data on renal histology are scarce. In this report, we describe the renal biopsies of two jaundiced patients with reduced creatinine clearance, and we critically review the literature on the pathogenesis of jaundice-related nephropathy. Normal renal architecture, indicating functional renal impairment, and extensive renal tubule necrosis were both observed in jaundice-related renal failure. The findings fit the original description of cholemic nephrosis. Both bilirubin and bile salts are potential nephrotoxins in animal models, but their precise role in the pathogenesis of jaundice-related nephropathy is not known. Patients with bilirubin plasma concentrations >20 mg/dL, a low serum albumin concentration or endo-toxemia, could be more prone to develop renal failure due to jaundice-related tubulopathy. In conclusion, jaundice-related nephropathy is essentially a tubulopathy, but the exact nature of the Pathogenesis is still uncertain.

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.

Semirigid ureteroscopy of the proximal ureter can be aided by external lower-abdominal pressure

BACKGROUND AND PURPOSE

Smaller semirigid ureteroscopes with large working channels and excellent optics are widely available. Ureteroscopic treatment of upper-ureteral stones has become increasingly popular, although flexible ureteroscopy is more frequently the method of choice. Access to the upper ureter with a semirigid ureteroscope (SR-URS) can be challenging and hazardous, especially when negotiating the iliac vessels. We sought to determine whether lower-abdominal pressure (LAP) facilitated SR-URS access to the upper ureter for safe laser lithotripsy.

PATIENTS AND METHODS

Thirty-two consecutive patients who underwent ureteroscopic management of upper- ureteral stones were evaluated. Twenty-four (75%) were male; seventeen (53%) had a right-sided stone. The mean largest stone diameter was 10.2 +/- 4.6 mm. These 32 patients were compared with a matched cohort of patients who underwent SR-URS procedures without the use of LAP.

RESULTS

Access to the upper ureter was possible in 30 patients (94%). The LAP was helpful in 18 patients (56%): it facilitated passage of the SR-URS in 16 patients (50%) and laser fiber placement in 11 cases (34%). Access to the upper ureter was possible in all women. The mean operative time was 54 minutes in the LAP group and 75 minutes in the matched cohort without LAP (P = 0.026). There were no significant deformities of the SR-URS and no complications.

CONCLUSIONS

Contrary to popular practice, the upper ureter can be accessed safely and efficiently with a 7.5F SR-URS in nearly all patients. Lower-abdominal pressure can be helpful to negotiate passage of the endoscope over the iliac vessels or to place the laser fiber on stones.