New endourologic technology for simultaneous holmium:YAG laser lithotripsy and fragment evacuation for PCNL: ex-vivo comparison to standard ultrasonic lithotripsy

Development and application of ultrasound contrast agents in biomedicine

With the rapid development of molecular imaging, ultrasound (US) medicine has evolved from traditional imaging diagnosis to integrated diagnosis and treatment at the molecular level. Ultrasound contrast agents (UCAs) play a crucial role in the integration of US diagnosis and treatment. As the micro-bubbles (MBs) in UCAs can enhance the cavitation effect and promote the biological effect of US, UCAs have also been studied in the fields of US thrombolysis, mediated gene transfer, drug delivery, and high intensity focused US. The application range of UCAs is expanding, and the value of their applications is improving. This paper reviews the development and application of UCAs in biomedicine in recent years, and the existing problems and prospects are pointed out.

Suction Use During Endourological Procedures

PURPOSE OF REVIEW

Equipment used in endourology is constantly evolving due to increasing incidence of urolithiasis. Suctioning has been used mainly in PCNL in conjunction with ultrasonic and ballistic devices for stone removal. Recently technological advances permitted the use of suctioning in more endourological techniques. This review aims to summarize the literature regarding these advancements and analyze the upcoming results.

RECENT FINDINGS

Several centers have conducted experimental and clinical studies on suctioning use during PCNL, mPCNL, and ureteroscopy and concluded that it is an effective and safe adjustment that improves stone-free rates and limits complication rates after these procedures. Suctioning use during common endourological procedures led to improved safety and efficacy among several indications. Due to the observational nature and small sample size of many studies, larger RCTs are needed to make safe conclusions.

EMS Lithoclast Trilogy™: an effective single-probe dual-energy lithotripter for mini and standard PCNL

PURPOSE

Several energy sources are available to clear stones during PCNL. Required improvements are faster stone clearance, optimized suction and ease of use while maintaining high patient safety standard. EMS LithoClast^® Trilogy, is the first device combining electromagnetic impactor with ultrasonic energy and suction, all-in-one probe. Animal studies and in vitro phantom stone studies have proven safety and efficacy of this device. We aim to study safety and clinical efficacy of Trilogy in our patients.

METHODS

31 patients with renal stones were included. Amplatz sheath sizes/Trilogy probe size was 22-28 Fr/10.2 Fr for standard PNL (n = 20) and 15 Fr./5.7 Fr for mini PNL access (n = 11). Analysis was done with respect to demography, stone characteristics, operation duration (total time and lithotripter activation time), post op Hb drop, clearance rate and adverse events. Stone area/volume was calculated based on CT using 3D doctor. Efficacy was determined by stone volume clearance rate (mm³/min).

RESULTS

Male:female ratio was 6:5 and 16:4 for mini (MPNL)/standard PNL (SPNL). Stone densities were 1229 ± 206 vs. 1168 ± 344 HU (MPNL vs. SPNL). Mean stone volumes were 3776.1 ± 2132 mm³ for MPNL and 7096 ± 6441 for SPNL. Mean stone volume clearance ratios were 370.5 ± 171 mm³/min and 590.7 ± 250mm³/min for MPNL and SPNL, respectively. Hb drop was 1.24 ± 0.64 g/dL (MPNL) and 1.23 ± 0.89gm/dL (SPNL). Total procedure time/lithotripter activation time was 53.4 ± 23.8/14.7 ± 12.4 min for MPNL and 65.2 ± 23.5/12.0 ± 8.9 for SPNL. Immediate post-operative/1 month stone clearance rates were 93%/96% with one clinically insignificant residual fragment (< 3 mm) and no necessity for auxiliary procedures. No device failure occured and three Clavien grade I and one grade II complications were observed.

CONCLUSION

Swiss LithoClast^® Trilogy provides fast stone clearance in standard/mini-PCNL procedures. Ease of use, high tissue safety and optimized suction that avoids fragment blockings are other key features.

Intracorporeal lithotripsy

Since the introduction of ESWL, PNL and URS during the early 1980s the application rate of ESWL has declined while those of PNL and URS have increased. This is mainly due to the facts that instruments and techniques for Intracorporeal Lithotripsy (IL) have made a continuous progress. This review shows that today an array of options for IL within the entire urinary tract is available to treat stones in a perfect minimal invasive way. At the same time further improvements of IL are already visible.

Clearance of Stone Fragments and Stone Dust by Continuous Flow Hydrodynamics in Percutaneous Renal Surgery: An In Vitro Study

PURPOSE

To investigate the capacity of stone clearance in common percutaneous nephrolithotomy (PCNL) systems achieved solely by hydrodynamic effects in an in vitro setting.

METHODS

A watertight cylindrical cast with a caliceal void served as an in vitro model. Various instruments for percutaneous renal surgery working with both continuous flow (fCF) and open Rutner sidearm (fCO) were tested. The model was loaded with standardized artificial stone material (2 mm in diameter) to examine stone removal by the vacuum cleaner effect and with sand (0.1-0.5 mm in diameter) to measure the washout effect caused by irrigation backflow. The association between washout of gravel and irrigation pressure was analyzed using ANOVA. Regression analysis was performed to assess the influence of the instruments' hydrodynamic characteristics-effective cross section of the outflow and irrigation flow volume.

RESULTS

Provoking the vacuum cleaner effect removal of stones was only effective in fCF but not in fCO instruments. Depending on irrigation pressure, the volumetric flow rate and effective cross section of the outflow clearance of sand could be observed in various medium- and large-sized fCF and fCO instruments, whereas in small-sized systems, clearance effects were negligible. Regression analysis showed clearance of stone dust strongly associated with an instrument's volumetric flow rate.

CONCLUSIONS

This in vitro study demonstrated that the application of medium- and large-sized fCF PCNL systems removes both "insignificant" stones and dust solely by hydrodynamic effects. Further studies have to show if these effects also occur in the in vivo situation.

Tissue damage from ultrasonic, pneumatic, and combination lithotripsy

PURPOSE

To conduct a comparative evaluation of ultrasonic, pneumatic, and dual ultrasonic (DUS) lithotripsy to predict the safety of probes on urinary tract tissue.

MATERIALS AND METHODS

The Swiss Lithoclast Ultra (ultrasonic-only [US] and ultrasonic-pneumatic combination [US+P]) and the Gyrus ACMI Cyberwand (DUS) were evaluated. Fresh porcine ureter, bladder, and renal pelvis tissues were used with a hands-free setup to vertically apply 0, 400, or 700 g of force with each probe for a duration of 3 seconds, 5 seconds, or 3 minutes (or until perforation occurred). Data collection included whether perforation occurred and time to perforation. Histological analysis of nonperforated samples was used to compare the anatomical depth to which damage occurred.

RESULTS

The total percentage of trials resulting in perforation for all tissue types, contact durations, and forces was found to be 8.5% (10/117) for US, 13.7% (16/117) for US+P, and 26.4% (31/117) for DUS. No perforations occurred with light contact (0 g) of probe force, regardless of tissue type, lithotripsy mode, or contact duration. Overall, the renal pelvis was most resistant to perforation (p=0.0004), while no difference was found between the bladder and ureter tissue (p=0.32). Force beyond 400 g and contact greater than 5 seconds increased risk for damage.

CONCLUSIONS

Mode of lithotripsy, tissue type, probe force, and probe-tissue contact duration all significantly impacted the extent of damage and likelihood for perforation to occur. All devices and tissue types provided a reasonable margin of safety for probe-tissue contact times of 3 and 5 seconds with no more than 400 g of force.

Comparison of percutaneous nephrolithotomy using pneumatic lithotripsy (lithoclast®) alone or in combination with ultrasonic lithotripsy

PURPOSE

Percutaneous nephrolithotomy (PCNL) is the procedure of choice for treating large renal stones. Pneumatic lithotripsy (Lithoclast®) is effective regardless of the stones' composition, and ultrasonic lithotripsy allows the aspiration of small debris during lithotripsy. We investigated the efficacy and safety of PCNL via Lithoclast® alone or combined with ultrasonic lithotripsy.

MATERIALS AND METHODS

Thirty-five (group A) and 39 (group B) patients underwent Lithoclast® PCNL and combination therapy, respectively, from May 2001 to March 2010, and the two groups were compared in terms of stone size, location, and composition; operative time; average number of treatments; hospital days; hemoglobin loss; ancillary procedures; rate of device failure; and initial and total stone-free rates.

RESULTS

The two groups did not differ significantly in preoperative stone size, location, or composition; the average number of treatments; or the initial and overall stone-free rates. However, combination therapy was associated with a significantly lower operative time (181±50 vs. 221±65 min, respectively, p=0.004), number of hospital days (11.6±3.8 vs. 14.2±4.4 days, respectively, p=0.009), and average hemoglobin loss (1.12±0.61 vs. 1.39±1.02 g/dl, respectively, p=0.013). Transfusions were required in 6 patients (4 and 2 in each group, respectively), but there were no significant complications related to percutaneous access. There were 2 (5.7%) mechanical failures (Lithoclast® probe fracture) in the group A and 5 (12.8%) in the group B (2 cases of suction tube obstruction, 3 cases of overheating).

CONCLUSIONS

The combination of ultrasonic lithotripter and Lithoclast® is more effective than Lithoclast® alone because it significantly decreases operative time, hemoglobin loss, and the hospital stay. This may reflect the superior power of Lithoclast® and the ability to aspirate the debris during ultrasonic lithotripsy.

Percutaneous nephroscopic with holmium laser and ultrasound lithotripsy for complicated renal calculi

The aim of this work is to validate the clinical efficacy of the high-power holmium:YAG laser with percutaneous nephrolithotripsy (PCNL) in combination with ultrasound lithotripsy for complicated renal calculi. From November 2006 to December 2007, 60 patients with complicated renal calculi were treated with PCNL, where an F24 standard renal access tract was established by percutaneous renal puncture under the guidance of B-mode ultrasound, and stones were fragmented and cleared by high-power holmium laser in combination with ultrasound under an F20.8 nephroscope. Of the 60 patients with complicated renal calculi, 20 were complete staghorn calculi and 30 were partial staghorn calculi, of which six patients were accompanied with renal insufficiency; two were solitary calculi, and eight were caliceal diverticular calculi. Calculi were removed by one attempt in 49 patients and by two attempts in 11 patients; through one tract in 50 patients and through two and three tracts in ten patients. The stone-free rate was 81.7%. No injury to the pleura and abdominal organs occurred during the intraoperative puncture. No postoperative blood transfusion was needed in any patient, nor did fever and secondary hemorrhage occur. The mean operation duration was 98 min (range, 60-150 min), and the mean lithotripsy time was 45 min (range, 30-85 min). Additional postoperative extracorporeal shock wave lithotripsy (ESWL) was performed on six patients. High-power holmium laser PCNL in combination with ultrasound lithotripsy is safe, effective, and minimally invasive, with a high stone-free rate, especially for complicated renal calculi.

Use of a Holmium laser to treat a forgotten double-J stent with whole stent encrustations: a case report

Short-term placement of double-J (D-J) ureteral stents after endourologic procedures and some open urological surgery is common. It is rare for a patient to forget about the indwelling D-J ureteral stent, and the major complications associated with that include infection, stone encrustation and multifractured stent. We report a case of a forgotten D-J ureteral stent, which had been placed 24 months previously during ureterorenoscopic lithotripsy, in a 62-year-old man who presented with flank soreness and recurrent urinary tract infection. Radiography of the kidney, ureter and bladder, and computed tomography demonstrated stone encrustation over the whole D-J stent. Cystolithotripsy and ureterorenoscopic lithotripsy with a Holmium laser were performed to remove the D-J. We believe that this is the first case of successful removal of an intact, encrusted stent in one procedure by endoscopic manipulation.

Lasers in percutaneous renal procedures

INTRODUCTION

Since the invention of lasers in 1960, they have been increasingly used in medicine. In this review paper, the types of lasers used in urology, in addition to their applications to percutaneous renal surgery will be reviewed. Specifically, use of lasers in the percutaneous management of renal stones, upper tract transitional cell carcinoma and stricture will be reviewed.

MATERIALS AND METHODS

Pubmed was searched for citations since 1966. The following terms were used: "lasers", "calculi", "endopyelotomy", and "transitional cell carcinoma".

RESULTS

Due to its minimal depth of penetration, holmium laser has proven to be safe and efficacious. It is currently the primary energy source for flexible instrumentation, and also has demonstrated efficacy in percutaneous lithotripsy (faster than ultrasonic lithotripsy and safer than electrohydraulic lithotripsy). Holmium laser been used for antegrade endopyelotomy and percutaneous resection of upper tract transitional cell carcinoma.

CONCLUSIONS

Holmium laser is safer than other lasers and has become the gold standard for laser lithotripsy for flexible instrumentation. It has been used successfully in the percutaneous management of renal stones, ureteropelvic junction obstruction, and upper tract transitional cell carcinoma. Holmium laser is an alternative energy source to conventional lithotripters and electrocautery for endopyelotomy and resection of upper tract transitional cell carcinoma.