Advances in Endourology

Highlights from the 21st World Congress on Endourology and Shockwave Lithotripsy

MEETING REVIEW Advances in Endourology Highlights from the 21st World Congress on Endourology and Shockwave Lithotripsy/19th Basic Research Symposium, September 21-24, 2003, Montreal, Canada [Rev Urol. 2004;6(2):82-85] © 2004 MedReviews, LLC Key words: Laparoscopy • Metabolic stone disease • Percutaneous nephrolithotomy • Shockwave lithotripsy • Ureteroscopy here were a number of innovative presentations at the 21st World Congress on Endourology and Shockwave Lithotripsy/19th Basic Research Symposium, held September 21-24, 2003, in Montreal. Here, the highlights of the basic research portion of the Congress are reviewed, grouped into the following categories: endoscopic simulators and skill acquisition, metabolic stone disease, shockwave lithotripsy, ureteroscopy, percutaneous surgery, the lower urinary tract, and laparoscopy. T Endoscopic Simulators and Skill Acquisition Simulators to facilitate endoscopic skill development have recently become Reviewed by Dean G. Assimos, MD, Department of Urology, Wake Forest University School of Medicine, Winston-Salem, NC 82 VOL. 6 NO. 2 2004 REVIEWS IN UROLOGY available. Ogan and colleagues1 reported that medical student performance on a virtual ureteroscopy simulator is predictive of outcomes of cadaveric ureteroscopic procedures. These findings are an important step in the validation process of this simulator as an indicator of endoscopic skill level. Knudsen and colleagues2 introduced a computer-based virtual reality simulator of percutaneous surgery. The effectiveness of this simulator will need to be assessed in future studies. A number of presentations provided insight into acquisition of learning skills. Anderson and colleagues3 reported that younger surgeons performed a group of standardized laparoscopic tasks more efficiently than older surgeons when a standard laparoscopic approach was used, whereas there were no age-related performance differences when robotic assistance was utilized. Nakada and colleagues4 reported that urologists attending a 2-day, hands-on laparoscopy course in which mentored videotape critique was employed had significant improvement in performance of standardized laparoscopic tasks. Metabolic Stone Disease Presentations on metabolic stone disease provided insight into the pathophysiology of stone formation, patient evaluation, and preventive therapy. Using advanced digital and endoscopic equipment, Kuo and colleagues5 measured fractional papillary Randall’s plaque coverage and found it to be higher in stone-formers. Urinary calcium excretion directly correlated with plaque coverage, whereas there was an inverse corre- 21st World Congress on Endourology and SWL lation with urinary volume. This same group of investigators performed papillary and renal cortical biopsies in idiopathic calcium oxalate stone–formers at the time of percutaneous nephrolithotomy (PNL).6 They found that Randall’s plaques are composed of calcium phosphate and that the initial sight of plaque formation is in the basement membrane of the loop of Henle. in a randomized clinical trial that SWL performed at a rate of 60 shocks per minute resulted in better fragmentation of renal calculi and superior stone-free rates compared with 120 shocks per minute. Young and colleagues11 found that a dual-pulse lithotriptor composed of a Dornier HM3 device with reflector insert and a piezoelectric lithotriptor resulted in improved stone fragmentation with Johnston and colleagues reported that ampicillin increased the in vitro solubility of cystine. Shah and colleagues7 reported that, in healthy adults following a prescribed metabolic diet (20% protein, 30% fat, 50% carbohydrate, 250 mg oxalate, 1000 mg calcium, all adjusted to 2500 kcal), urinary metabolic stabilization was achieved within 48 hours. These results indicate that lead-in times for healthy persons following this metabolic diet can be shortened from the typical 7- to 10-day period used by a number of investigators. Ekeruo and colleagues8 analyzed metabolic abnormalities and stone composition in obese persons. They found that uric acid stones were the most prevalent (63%) in this population. Hypercalciuria, low urine volume, gouty diathesis, hyperuricosuria, and hyperoxaluria were the most common metabolic abnormalities, which is reflective of underlying purine gluttony. Johnston and colleagues9 reported that ampicillin increased the in vitro solubility of cystine. Further studies are needed to determine whether this agent will be useful in the management of cystinuric patients. Shockwave Lithotripsy Methods and technology to improve results of shockwave lithotripsy (SWL) were presented during this session. Pace and colleagues10 demonstrated less renal injury in a porcine model. The piezoelectric generator produces a shock wave that is emitted after the electrohydraulic shock wave, resulting in collapse of cavitation bubbles from the initial shock wave at the stone surface and thus in better fragmentation. The inserted reflector attenuates cavitation-induced renal injury. Ureteroscopy There is an ongoing debate regarding the optimal therapy for patients with lower pole renal calculi. Kuo and col- to 25 mm in aggregate size.13 The stone-free rate was significantly greater, and morbidity was slightly higher, in the subjects who underwent PNL. Improvements in flexible ureteroscopic technology were highlighted. Grasso and Johnson14 presented their experience with a flexible ureteroscope with greater than 300º primary active deflection and noted that it facilitated a number of ureteroscopic procedures. Placement of instruments through the working sheath attenuated deflection, but deflection was still greater than 180º. Lee and colleagues15 reported on a temperature-activated Nitinol sheath, which can be placed with a laser fiber through the working channel of a flexible ureteroscope. Deflection is limited to a lesser extent when this sheath is used. Fluid absorption is a potential complication of ureterorenoscopy. Cybulski and colleagues16 carefully assessed fluid absorption in 16 patients subjected to ureteroscopic procedures. Results showed that a mean of 54 mL of fluid was systemically absorbed (range, 4-137 mL). The amount of fluid absorbed was directly related to Challacombe and colleagues demonstrated that transoceanic telerobotic percutaneous renal access is feasible. leagues12 reported results of a multicenter, randomized, prospective trial comparing SWL and ureteroscopy for the treatment of lower pole renal calculi less than 10 mm in aggregate size: the stone-free rate was superior in subjects who underwent ureteroscopy, and the need for secondary intervention was greater in those who underwent SWL. The same group of investigators reported results of a randomized, prospective study comparing ureteroscopy and PNL for the management of lower pole stones 11 the length of the procedure and was estimated to be 1 mL/min. Percutaneous Surgery Several innovations for percutaneous renal surgery were presented. Challacombe and colleagues17 demonstrated that transoceanic telerobotic percutaneous renal access is feasible. Lobik and colleagues18 evaluated a new-generation orthogonal deflecting flexible cysto/nephroscope with 2 active deflections, which can be activated in different planes perpen- VOL. 6 NO. 2 2004 REVIEWS IN UROLOGY 83 21st World Congress on Endourology and SWL continued dicular to each other or in 2 opposite directions, with a total angle of 350º. This may facilitate endoscopy of the renal collecting system, bladder, augmented bladders, neo-bladders, and cutaneous diversions. The Lower Urinary Tract Interesting presentations on the lower urinary tract were delivered. DiTrolio and Dubocq19 reported that pellets containing high concentrations of sodium chloride implanted in rat liver generated tissue necrosis. They propose that transrectal deliv- and colleagues21 reported that viable cells were seen within the staple lines at the ureterovesical junction in swine 6 weeks after nephroureterectomy in which the distal bladder cuff was secured with a stapling device. These findings indicate that this technique may have oncologic ramifications. Uribe and colleagues22 reported that fibrin glue and oxidized regenerated cellulose, materials that may be used during laparoscopic or open partial nephrectomy, assume a semisolid, gelatinous state when mixed with urine in an in vitro system. This DiTrolio and Dubocq reported that pellets containing high concentrations of sodium chloride implanted in rat liver generated tissue necrosis. ery of such pellets to the prostate may prove to be suitable therapy for benign prostatic hyperplasia. Molina and colleagues20 used an argon beam coagulator to ablate the mucosa of ileum used for enterocystoplasty in swine and found that this allowed resurfacing with transitional cell epithelium. This technique may prove to limit mucus-related problems in patients undergoing this procedure. Laparoscopy Several novel studies on laparoscopic techniques were presented. Venkatesh “matrix” was shown to still be present at 5 days after incubation; thus, these investigators demonstrated the potential for “iatrogenic stones.” El-Hakim and colleagues23 identified several ergonomic risk factors for the development of neuromuscular problems in surgeons after performing laparoscopic procedures. Risk factors include static posture of the head and neck, extreme and frequent upper arm motion, use of finger-grip instruments, increased height of the operating table, improper suturing technique, limited surgical experience, and an instrument angle of greater than 45º relative to the surgeon’s sagittal plane. Summary The aforementioned studies, as well as many others presented at this meeting, reflect the progress and innovation that is occurring in the field of endourology. The future utilization of these advancements in knowledge and technology will undoubtedly translate into improved patient care. References 1. 2. 3. 4. 5. 6. 7. Ogan K, Jacomides L, Roehrborn CG, et al. Medical student performance on a virtual ureteroscopy simulator predicts performance on cadaveric ureteroscopy [abstract]. J Endourol. 2003;17(suppl):A1. Abstract MP01.02. Knudsen BE, Beiko DT, Watterson JD, et al. A new computer-based virtual reality simulator for percutaneous renal access: PERC Mentor™ [abstract]. J Endourol. 2003;17(suppl):A1-A2. Abstract MP01.03. Anderson DA, Wang DS, Winfield HN. Do younger physicians acquire laparoscopic skills faster than their senior colleagues? Influence of the daVinci™ robotic system [abstract]. J Endourol. 2003;17(suppl):A2. Abstract MP01.05. Nakada SY, Hedican SP, Bishoff JT, et al. Expert videotape analysis and critique benefits laparoscopic skills training of urologists [abstract]. J Endourol. 2003;17(suppl):A2-A3. Abstract MP01.06. Kuo RL, Lingeman JE, Evan AP, et al. Urine calcium and volume predict coverage of renal papilla by Randall’s plaque [abstract]. J Endourol. 2003;17(suppl):A16. Abstract MP03.01. Evan AP, Lingeman JE, Parks J, et al. Renal crystal deposition begins in basement membrane of loops of Henle of CaOx stone formers [abstract]. J Endourol. 2003;17(suppl):A17. Abstract MP03.03. Shah O, Lovato J, Holmes RP, Assimos DG. Urinary responses to a controlled, metabolic diet Main Points • Ogan and colleagues reported that medical student performance on a virtual ureteroscopy simulator is predictive of outcomes of cadaveric ureteroscopic procedures. • Ekeruo and colleagues analyzed stone composition in obese persons and found uric acid stones to be the most prevalent (63%). • Results of a randomized clinical trial demonstrated that shockwave lithotripsy (SWL) performed at a rate of 60 shocks per minute resulted in better fragmentation of renal calculi and superior stone-free rates compared with 120 shocks per minute. • Kuo and colleagues reported results of a multicenter, randomized, prospective trial comparing SWL and ureteroscopy for the treatment of lower pole renal calculi less than 10 mm in aggregate size: the stone-free rate was superior in subjects who underwent ureteroscopy, and the need for secondary intervention was greater in those who underwent SWL. • The potential of “iatrogenic stones” was demonstrated by Uribe and colleagues, who showed that fibrin glue and oxidized regenerated cellulose, materials that may be used during laparoscopic or open partial nephrectomy, can assume a semisolid state when mixed with urine in an in vitro system. 84 VOL. 6 NO. 2 2004 REVIEWS IN UROLOGY 21st World Congress on Endourology and SWL 8. 9. 10. 11. 12. [abstract]. J Endourol. 2003;17(suppl):A19. Abstract MP03.08. Ekeruo WO, Young MD, Springhart WP, et al. Impact of medical therapy on the management of nephrolithiasis in obese patients [abstract]. J Endourol. 2003;17(suppl):A21. Abstract MP03.13. Johnston WK III, Casey R, Higashi R, et al. The effects of ampicillin on cystine solubility in solution [abstract]. J Endourol. 2003;17(suppl):A21A22. Abstract MP03.15. Pace K, Harju M, Dyer S, Honey RJ, and the University of Toronto Lithotripsy Group. Shock wave lithotripsy: final results of a randomized, single-blinded trial to compare shock wave frequencies of 60 and 120 shocks per minute [abstract]. J Endourol. 2003;17(suppl):A33-A34. Abstract MP05.06. Young MD, Zhou Y, Ekerou WO, et al. Improved stone comminution and simultaneously reduced tissue injury with an upgraded electrohydraulic lithotripter: in vivo studies [abstract]. J Endourol. 2003;17(suppl):A33. Abstract MP05.04. Kuo RL, Lingeman JE, Leveillee RJ, et al, and the Lower Pole II Study Group. A randomized clinical 13. 14. 15. 16. 17. trial of ESWL and ureteroscopy for lower pole stones less than 10mm [abstract]. J Endourol. 2003;17(suppl):A38. Abstract MP05.19. Kuo RL, Lingeman JE, Leveillee RJ, et al, and the Lower Pole II Study Group. A randomized clinical trial of ureteroscopy and percutaneous nephrolithotomy for lower pole stones between 11 and 25mm [abstract]. J Endourol. 2003;17(suppl):A31. Abstract MP04.22. Grasso M, Johnson GB. Exaggerated primary endoscope deflection: initial clinical experience with prototypic endoscopes, the first 115 procedures [abstract]. J Endourol. 2003;17(suppl):A24. Abstract MP04.03. Lee C, Anderson JK, Marquez J, Monga M. Temperature-activated deflection of a novel laser fiber sheath [abstract]. J Endourol. 2003;17(suppl):A25-A26. Abstract MP04.07. Cybulski P, Honey RJD, Pace K. Fluid absorption during ureterorenoscopy [abstract]. J Endourol. 2003;17(suppl):A25. Abstract MP04.06. Challacombe B, Glass J, Smeeton N, et al. Transoceanic tele-robotic access to the kidney [abstract]. J Endourol. 2003;17(suppl):A39. Abstract MP06.02. 18. 19. 20. 21. 22. 23. Lobik L, Leveillee RJ, Lopez-Pujals A. Initial experience with a new generation orthogonal deflecting flexible cystonephroscope [abstract]. J Endourol. 2003;17(suppl):A39. Abstract MP06.03. DiTrolio JV, Dubocq FM. The use of biodegradable sodium chloride pellets for chemoablation of the prostate [abstract]. J Endourol. 2003;17(suppl):A12. Abstract MP02.14. Molina W, Sharp DS, Spaliviero M, et al. Bowel de-mucosalization using argon beam coagulation–potential for enterocystoplasty [abstract]. J Endourol. 2003;17(suppl):A13. Abstract MP02.16. Venkatesh R, Landman J, Rehman J, et al. Viability of cells within the staple lines following laparoscopic bladder stapling in a porcine model [abstract]. J Endourol. 2003;17(suppl):A4. Abstract MP01.10. Uribe C, Eichel L, Khonsari S, et al. What happens to hemostatic agents in contact with urine? An in vitro study [abstract]. J Endourol. 2003;17(suppl):A42. Abstract MP06.11. El-Hakim A, Marcovich R, Chiu KY, et al. Ergonomic risk factors contributing to laparoscopic surgeon morbidity [abstract]. J Endourol. 2003;17(suppl):A5. Abstract MP01.12. VOL. 6 NO. 2 2004 REVIEWS IN UROLOGY 85