Ureteroscopic surgery: changing times and perspectives

Minimally Invasive Surgery for the Treatment of Ureteric Stones - State-of-the-Art Review

The landscape of managing ureteric stones has evolved over the last few decades and several treatment options exist depending on the stone size, location, and other patient and stone factors. While open surgery is now rarely performed, the use of medical expulsive therapy (MET) has been controversial and perhaps only recommended for large distal ureteric stones. The mainstay treatment balances between shockwave lithotripsy (SWL) and ureteroscopy (URS), with the latter usually recommended for larger stones. While the principles of ureteric stone management have remained largely unchanged, the modern era has generated new methods and means to deliver it. Advancements have occurred in all domains of endourology to try and refine treatment and balance it with cost, patient choice and quality of life. Dissemination of technologies and demonstration of their efficacy and safety will eventually result in new recommendations among international guidelines and evolution of new gold standards.

[Bilateral renal sclerotherapy as a treatment option in a mixed breed male dog with idiopathic renal haematuria]

A 2-year-old male castrated German Shepherd dog mix was presented with chronic macroscopic haematuria. Further diagnostics included abdominal ultrasound and urethrocystoscopy and led to a diagnosis of severe bilateral idiopathic renal haematuria (IRH). Medical treatment with Yunnan Baiyao was unsuccessful. Bilateral renal-sparing sclerotherapy was performed and, despite distal migration of both ureteral stents within 12 days, permanently resolved the macroscopic haematuria.

Impact of pulse duration on Ho:YAG laser lithotripsy: treatment aspects on the single-pulse level

OBJECTIVES

Holmium-YAG (Ho:YAG) laser lithotripsy is a multi-pulse treatment modality with stochastic effects on the fragmentation. In vitro investigation on the single-pulse-induced effects on fiber, repulsion as well as fragmentation was performed to identify potential impacts of different Ho:YAG laser pulse durations.

MATERIALS AND METHODS

A Ho:YAG laser system (Swiss LaserClast, EMS S.A., Nyon, Switzerland) with selectable long- or short-pulse mode was tested with regard to fiber burn back, the repulsion capacity using an underwater pendulum setup and single-pulse-induced fragmentation capacity using artificial (BEGO) stones. The laser parameters were chosen in accordance with clinical application modes (laser fiber: 365 and 200 µm; output power: 4, 6 and 10 W in different combinations of energy per pulse and repetition rate). Evaluation parameters were reduction in fiber length, pendulum deviation and topology of the crater.

RESULTS

Using the long-pulse mode, the fiber burn back was nearly negligible, while in short-pulse mode, an increased burn back could be observed. The results of the pendulum test showed that the deviation induced by the momentum of short pulses was by factor 1.5-2 higher compared to longer pulses at identical energy per pulse settings. The ablation volumes induced by single pulses either in short-pulse or long-pulse mode did not differ significantly although different crater shapes appeared.

CONCLUSION

Reduced stone repulsion and reduced laser fiber burn back with longer laser pulses may result in a more convenient handling during clinical application and thus in an improved clinical outcome of laser lithotripsy.

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.

Impact of pulse duration on Ho:YAG laser lithotripsy: fragmentation and dusting performance

Objectives

In vitro investigations of Ho:YAG laser-induced stone fragmentation were performed to identify potential impacts of different pulse durations on stone fragmentation characteristics.

Materials and methods

A Ho:YAG laser system (Swiss LaserClast, EMS S.A., Nyon, Switzerland) with selectable long or short pulse mode was tested with regard to its fragmentation and laser hardware compatibility properties. The pulse duration is depending on the specific laser parameters. Fragmentation tests (hand-held, hands-free, single-pulse-induced crater) on artificial BEGO stones were performed under reproducible experimental conditions (fibre sizes: 365 and 200 µm; laser settings: 10 W through combinations of 0.5, 1, 2 J/pulse and 20, 10, 5 Hz, respectively).

Results

Differences in fragmentation rates between the two pulse duration regimes were detected with statistical significance for defined settings. Hand-held and motivated Ho:YAG laser-assisted fragmentation of BEGO stones showed no significant difference between short pulse mode and long pulse mode, neither in fragmentation rates nor in number of fragments and fragment sizes. Similarly, the results of the hands-free fragmentation tests (with and without anti-repulsion device) showed no statistical differences between long pulse and short pulse modes.

Conclusion

The study showed that fragmentation rates for long and short pulse durations at identical power settings remain at a comparable level. Longer holmium laser pulse duration reduces stone pushback. Therefore, longer laser pulses may result in better clinical outcome of laser lithotripsy and more convenient handling during clinical use without compromising fragmentation effectiveness.

Contemporary management of ureteral stones

CONTEXT

Ureteral calculi represent a common condition that urologists encounter in everyday practice. Several treatment options are available for calculi that do not pass spontaneously or are unlikely to do so.

OBJECTIVE

In this nonsystematic review, we summarize the existing data on contemporary management of ureteral stones focusing on medical expulsive therapy (MET) and different treatment modalities.

EVIDENCE ACQUISITION

A PubMed search was performed. We reviewed the recent literature on the management of ureteral calculi. Articles were considered between 1997 and 2011. Older studies were included selectively if historically relevant.

EVIDENCE SYNTHESIS

For stones that do not pass spontaneously or with MET, shock wave lithotripsy (SWL) and ureteroscopy (URS) are the most common and efficient treatment modalities. Both techniques have obvious advantages and disadvantages as well as different patterns of complications. For select cases or patients, other modalities may be useful.

CONCLUSIONS

Ureteral stones of up to 10mm and eligible for observation may be offered MET. For most ureteral calculi that require treatment, advances in SWL and URS allow urologists to take a minimally invasive approach. Other more invasive treatments are reserved for select "nonstandard" cases.

The PolyScope: a modular design, semidisposable flexible ureterorenoscope system

PURPOSE

To characterize the mechanical and optical properties of the PolyScope endoscope system and to examine the clinical outcome in patients who were undergoing ureteronephroscopy.

MATERIALS AND METHODS

Mechanical assessment involved measurement of the deflection angle and irrigation flow rate. Optical resolution and distortion, field and angle of view, and light transmission and output formed the optical assessment. Clinical assessment was made in a series of consecutive ureteronephroscopy procedures. The optical cord was disconnected after each procedure, and the image fiber was assessed for damage.

RESULTS

The mean value for the angle of maximum active tip deflection with an empty working channel was 265 degrees (261-275 degrees). Deflection was impaired most with insertion of the 3.0 F basket (10% decrease) and least with an indwelling 220 microm laser fiber (2% decrease). Irrigation flow rate was 57 mL/min with an empty working channel. Flow was reduced by 50% and 68%, with the insertion of a 200 microm or 365 microm laser probe, respectively, and by 92.5% with a 3.2F basket. No damage to the image fiber occurred. The PolyScope optics system could identify a target of about 0.125 mm at a distance of 2 to 4 mm, based on 3 line-pairs/mm needed for clear identification. Lithotripsy of renal calculi was performed for 40 stone burdens in 32 patients; the resulting stone-free rate was 87.5%.

CONCLUSION

The novel semidisposable ureteroscope system PolyScope was simple to use, effective, and reliable in this preliminary clinical evaluation. It overcomes the inherent fragility of comparable devices, which renders the need for maintenance unnecessary.

The history of NOTES

Throughout history, medicine has witnessed paradigm shifts that significantly change patient treatment. Recently, the introduction and development of laparoscopic surgery has had a major impact on patient treatment. On the horizon is natural orifice translumenal endoscopic surgery (NOTES), which has tremendous potential. This review focuses on the history of natural orifice endoscopy in urology with the progression through therapeutic natural orifice endoscopy and resection to the development of upper tract natural orifice surgery. Further delineated is how technology has improved these procedures to set the stage for NOTES.