Evaluation of intrarenal pressure stability at different lithotripter suction settings in a porcine kidney model.

PURPOSE: Using the Swiss LithoClast® Trilogy, urinary stones can be fragmented and removed simultaneously by suction at different selectable suction settings. The aim was to evaluate pressure stability at different settings and test stone fragmentation and suction at the optimal settings. METHODS: In an ex vivo porcine kidney model, we recorded intrarenal pressure levels with different suction levels. Storz® Nephroscopes MIP-M and MIP-L and Swiss LithoClast® Trilogy probes were used. RESULTS: Pressure stabilized at 19 cm H2O with the MIP-M at 1 m gravity irrigation with no instrument introduced. After inserting the 1.5 mm probe, the pressure dropped to 5 cm H2O. With a suction setting of 10%, the pressure stabilized at 3 cm H2O and remained stable for the maximum time of 120 s. After increasing the suction to 20, 30, 40, and 50%, we recorded the pressure drop time to 0 after 22, 14, 11, and 8 s. Using the MIP-L, pressure stabilized at 44 cm H2O and decreased to 8 cm H2O after inserting the 3.4 mm probe. With 10% suction, a pressure stabilization was measured at 2 cm H2O and remained stable for 120 s. At suction levels of 20 and 30%, the pressure drop time to 0 was 6 and 5 s. With a 10% suction, removing stones was efficient, and the kidney's filling volume was maintained. CONCLUSIONS: When using the LithoClast® Trilogy, a suction setting of 10% seems to be optimal for the treatment of urinary calculi when applying suction continuously.

Adherence to guidelines in the management of urolithiasis: are there differences among distinct patient care settings?

INTRODUCTION: Urolithiasis is a common diagnosis in urology. New technologies offer a variety of diagnostic and therapy and consequently display a financial burden on healthcare systems. Hence, clinical practice guidelines (CPG) are essential to implement evidence-based medicine and assure a standard of care considering limited resources. To date, there is no evidence of the use and adherence to CPG on urolithiasis. MATERIAL AND METHODS: Therefore, we performed a cross-sectional study to analyze the use of CPG on urolithiasis. Data collection was carried out by a questionnaire given to 400 German urologists. The survey included use and adherence to guidelines, evaluation of the clinical situation, therapy spectrum, and workplace. In total, 150 (37%) questionnaires were received and included in our survey. Statistics were performed by SPSS using Chi-quadrat test/Fisher's exact test. RESULTS: In our study, urologists were office based, hospital affiliated, non-academic, or academic centers in 53%, 32%, 16% and 5%, respectively. In 74% and 70%, urologists adhere to CPG in diagnostic and therapy. Interestingly, workplace and therapy spectrum determines the use of different CPG (p = 0.01; p = 0.022). Academic urologists were more likely to use international CPG of EAU (40%), while outpatient urologists significantly orientated on national CPG (46%). 86% of urologists with high volume of urolithiasis practice interventions in contrast to 53% in low volume (p = 0.001). More than 80% of urologists use short versions and app version of CPG. CONCLUSION: We firstly describe compliance and the use of CPG on urolithiasis. EAU and DGU present the most commonly used CPG. Short version and app version of CPG find frequent clinical utilization.

Comparison of stone elimination capacity and drilling speed of endoscopic clearance lithotripsy devices.

PURPOSE: To investigate the fragmentation capacity, clearance time, and drilling speed of combined ultrasonic with impact dual-energy and single energy ultrasonic lithotripter devices. METHODS: Stone fragmentation and clearance tests were performed under direct view in an underwater layered hemisphere by four different operators using artificial stones (n = 10/operator). Time for complete clearance was measured. Drilling tests were performed using an underwater setup, consisting of a mounting rack for fixing the lithotripter handpiece with the probe in vertical position and in contact with the stone phantom placed on one side of a balance for defined and constant contact application pressure equivalent to 450 g load. Time until complete perforation or in case of no perforation, the penetration depth after 60 s into the stone sample was recorded. Four devices, one single energy device (SED), one dual-energy dual probe (DEDP), two dual-energy single probe (DESP-1, DESP-2), with different parameters were tested. RESULTS: Stone fragmentation and clearance speed were significantly faster for dual-energy device DESP-1 compared to all other devices (p < 0.001). Using DESP-1, the clearance time needed was 26.0 ± 5.0 s followed by DESP-2, SED and DEDP requiring 38.4 ± 5.8 s, 40.1 ± 6.3 s and 46.3 ± 11.6 s, respectively. Regarding the drilling speed, DESP-1 was faster compared to all other devices used (p < 0.05). While the drilling speed of DESP-1 was 0.69 ± 0.19 mm/s, compared to 0.49 ± 0.18 mm/s of DESP-2, 0.47 ± 0.09 mm/s of DEDP, and 0.19 ± 0.03 mm/s of SED. CONCLUSIONS: The dual-energy/single-probe device combining ultrasonic vibrations with electromechanical impact was significantly faster in fragmentation and clearing stone phantoms as well as in drilling speed compared to all other devices.

Comparative evaluation of tissue damage induced by ultrasound and impact dual-mode endoscopic lithotripsy versus conventional single-mode ultrasound lithotripsy.

OBJECTIVE: The aim of our study was to perform comparative investigation of the tissue safety of three different endoscopic lithotripter devices including a new single-probe/dual-energy lithotripter in an in vivo animal model. The Swiss LithoClast Trilogy was compared to the Storz Calcuson and the Swiss LithoClast Vario. The safety test simulated the accidental direct contact between lithotripter probes and the urothelium, which can occur when sliding off a stone or drilling through a calculus during lithotripsy. The safety test included a smallest (1.5 mm) and largest (3.3/3.4 mm) probe diameter per device. METHODS: Testing was performed in nine pigs (three animals per device). The bladder tissue was exposed to direct lithotripter probe contact at maximum power for 10 s to produce visible tissue lesions. Acute tissue trauma was evaluated using a simplified scoring model describing the expected bladder wall injuries for histological examination. After 7 days, all animals were killed, necropsied and examined post mortem. For between-group comparisons regarding microscopic histopathologic features, a Chi-square test was used. A p value < 0.05 was considered to be statistically significant. RESULTS: Irrespective of the lithotripter used, no systemic signs of toxicity were observed. Histologically, signs of normal ongoing healing were observed on the bladder mucosa. There were no significant differences in histological findings taking changes of the epithelium (p = 0.360), the leucocyte infiltration (p = 0.123), the vascular congestion (p = 0.929) and the edema (p = 1.0) between the groups into account. CONCLUSIONS: The results of this study demonstrated a comparable safety between all lithotripsy devices.

Transrectal ultrasound guided prostate biopsy in the era of increasing fluoroquinolone resistance: prophylaxis with single-dose ertapenem.

PURPOSE: The aim of the study was to compare single-dose ertapenem (ERT) with the 3-day regime of ciprofloxacin (CIP) for prophylaxis of possible infections following transrectal prostate biopsy. METHODS: Data from a consecutive group of 542 patients from January 2012 to January 2017 were retrospectively analysed. As preinterventional prophylaxis patient group A (179) received 500 mg CIP twice a day for three days, beginning on the day before the biopsy (until June 2013); group B (363) received a single dose of ERT 60 min prior to intervention. The first follow-up examination for all patients was between post-intervention days 2 and 3. The second follow-up examination was between day 15 and 30 following biopsy. Urine was cultured in all cases and any adverse drug reactions (ADRs) related to the antibiotic treatment were noted. We also recorded all clinically relevant morbidities requiring intervention (ischuria, macrohaematuria, symptomatic urinary tract infections and urosepsis), as well as those not requiring active intervention (macrohaematuria, decreased urinary stream, pain, haemospermia). The main study criterion was the symptomatic urinary tract infection rate and ADRs. RESULTS: All 542 biopsied patients could be included in the study and the drop-out rate was zero. There were no significant differences between groups A and B with regards to complications not requiring intervention. There was, however, a significant reduction from 14.5% (group A) to 0.8% (group B) in infectious complications. This showed a significant correlation in favour of ERT (p < 0.001). Furthermore, in the ERT group there was also a distinct and significant reduction (p > 0.001) in the number of patients with bacteriuria (>10e4 cfu per ml urine) without fever (0.5%) compared to the CIP group (12.3%). CONCLUSION: A single-dose of 1 g of intravenous ERT applied 1 h before a scheduled transrectal prostate biopsy is a safe option and provides effective protection against infection-related complications arising from surgery.

Evaluation of the 'Prostate Interdisciplinary Communication and Mapping Algorithm for Biopsy and Pathology' (PIC-MABP).

INTRODUCTION: Experience from interdisciplinary cooperation revealed the need for a prostate mapping scheme to communicate multiparametric MRI (mpMRI) findings between radiologists, urologists, and pathologists, which should be detailed, yet easy to memorize. For this purpose, the 'Prostate interdisciplinary communication and mapping algorithm for biopsy and pathology' (PIC-MABP) was developed. This study evaluated the accuracy of the PIC-MABP system. METHODS: PIC-MABP was tested and validated in findings of 10 randomly selected patients from routine clinical practise with 18 histologically proven cancer lesions. Patients received an mpMRI of the prostate prior to prostatectomy. After surgery the prostates were prepared as whole-mount step sections. Cancer lesions, which were found suspicious on mpMRI, were assigned to the according PIC-MABP sectors by a radiologist. MpMRI slides were masked and sent to seven urologists from different centres, providing only the PIC-MABP location of each lesion. Urologists marked the accordant regions. Then mpMRI slides were unmasked, and the correctness of each mark was evaluated. RESULTS: One hundred and seventeen of the 126 marks (93%) were correctly assigned. Detection rates differed for lesions >0.5 cc compared with lesions <0.5 cc (p < 0.005): 3/7 (43%) marks were correctly assigned in lesions <0.3 cc, 16/21 (76%) in lesions with 0.3-0.5 cc, and 98/98 (100%) in lesions >0.5 cc. Interobserver agreement was good for lesions >0.5 cc and poor for lesions <0.3 cc (Fleiss Kappa 1 vs. 0.0175). CONCLUSION: PIC-MABP seems to be a reliable system to communicate the location of mpMRI findings >0.5 cc between different disciplines and can be a useful guidance for cognitive mpMRI/TRUS fusion biopsy.

Single fraction radiosurgery for the treatment of renal tumors.

PURPOSE: High dose local stereotactic radiosurgery was performed in select patients to improve local tumor control and overall survival. We report on patients with renal tumors treated with single fraction robotic stereotactic radiosurgery. MATERIALS AND METHODS: A total of 40 patients with a median age of 64 years who had an indication for nephrectomy and subsequent hemodialysis were entered in a prospective case-control study of single fraction stereotactic radiosurgery. Of the patients 11 had transitional cell cancer and 29 had renal cell cancer. Tumor response, renal function, survival and adverse events were estimated every 3 months. Followup was at least 6 months. RESULTS: A total of 45 renal tumors were treated. Median followup was 28.1 months (range 6.0 to 78.3). The local tumor control rate 9 months after stereotactic radiosurgery was 98% (95% CI 89-99). There was a measurable size reduction in 38 lesions, including complete remission in 19. Renal function remained stable. Using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation median creatinine clearance was 76.8 (range 25.3 to 126.3) and 70.3 ml/minute/1.73 m(2) (range 18.6 to 127.3) at baseline and followup, respectively (p = 0.89). Grade I erythrodermia developed in 1 patient, 3 reported grade I fatigue and 2 reported grade I nausea. Nephrectomy was avoided in all cases. CONCLUSIONS: Single fraction stereotactic radiosurgery as an outpatient procedure is a treatment modality with short-term safety and efficacy. It avoids treatment related loss of renal function and hemodialysis in select patients with transitional or renal cell cancer. At short followup oncologic results were similar to those of other ablative techniques for renal tumors. To date functional results have been excellent. Further studies are needed to determine the long-term results and limits of stereotactic radiosurgery in this setting.

Flow matters 2: How to improve irrigation flow in small-calibre percutaneous procedures-the purging effect.

INTRODUCTION: Aim of this study was to investigate whether the combination of high-pressure irrigation inflow combined with simultaneous sensor-controlled suction could improve irrigation turnover without leading to high peak intrarenal pressure in small-calibre percutaneous instruments (SCPI). M + M: A MIP XS sheath (9.5 Fr. outer diameter and 8.5 Fr. inner diameter) and a 7.5-Fr. nephroscope (3-Fr. irrigation channel; MIP XS by Nagele, Karl Storz, Tuttlingen, Germany) was inserted into the collecting system of a non-perfused cadaveric porcine kidney, an 8-Fr. mono-J catheter was introduced through the ureter. Irrigation was performed using a pressure-controlled, combined irrigation/suction pump (Uromat E.A.S.I., Karl Storz, Tuttlingen, Germany) in either single-flow or continuous-flow (=combination of irrigation and suction) mode. Intrarenal pressure was measured and irrigation fluid turnover was measured by a cystometry catheter inserted trans-parenchymally into the renal pelvis. Pressure changes were recorded by a urodynamic workstation. RESULTS: Applying pressure-controlled suction, irrigation fluid turnover could be increased by 5 % at an inflow pressure of 75 mmHg (80-84 ml/min) and 15 % at an inflow pressure of 110 mmHg (196-110 ml/min). Suction decreased the intrarenal pressure by 14 % at 75 mmHg (19-14.5 cm H2O) and 28 % at 110 mmHg inflow pressure (37-26.5 cm H2O). CONCLUSION: Although combination of pressure irrigation with sensor-controlled suction increases irrigation flow in SCPI, the intrarenal pressure could be reduced with combined suction via a transurethral mono-J catheter. This irrigation method in percutaneous surgery is called purging effect.

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.

The vacuum cleaner effect in minimally invasive percutaneous nephrolitholapaxy.

INTRODUCTION: Percutaneous stone removal increasingly plays an important role among the different approaches of interventional stone therapy, particularly since the development of miniaturized instruments is resulting in lower morbidity for the patients. One major drawback of smaller instruments is the increased difficulty of stone retrieval after disintegration due to the reduced tract diameter. This results in longer operation time and the need of additional tools such as disposable retrieval baskets. One of the key factors in the development of minimally invasive percutaneous nephrolitholapaxy (MIP) was the design of an Amplatz sheath which provides a built-in vacuum cleaner effect for stone retrieval. METHODS: A series of flow analyses with the gauges and shapes of the most commonly used nephroscopes and sheaths in percutaneous nephrolitholapaxy was performed by computational fluid dynamics. Flow velocity and direction in front of the nephroscope were computed and visualized by the software. RESULTS: In our study, the vacuum cleaner effect developed exclusively when a round-shaped nephroscope was used (Nagele Miniature Nephroscope System, Karl Storz GmbH & Co. KG) and depended on the relation between nephroscope diameter and inner sheath diameter. The strongest effect was observed with a 12 F nephroscope and an inner sheath diameter of 15 F. It did not develop when an oval- or crescent-shaped nephroscope was used. In front of the distal end of the round-shaped nephroscope, a slipstream develops, induced by the excursive change of width of the fluid flow on the outlet of the flushing canal. This allows the adhesion of a stone fragment in the eddy while the fluid flow is circulating around the stone. CONCLUSION: This study illustrates and explains the vacuum cleaner effect which has been detected in the development of the Nagele Miniature Nephroscope System used in MIP. It combines the reduced morbidity of smaller kidney puncture diameters with the benefit of quick and complete stone removal.

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.

Efficacy and safety of Ho:YAG laser lithotripsy for ureteroscopic removal of proximal and distal ureteral calculi.

BACKGROUND: Laser lithotripsy is an established endourological modality. Ho:YAG laser have broadened the indications for ureteroscopic stone managements to include larger stone sizes throughout the whole upper urinary tract. Aim of current work is to assess efficacy and safety of Ho:YAG laser lithotripsy during retrograde ureteroscopic management of ureteral calculi in different locations. METHODS: 88 patients were treated with ureteroscopic Ho:YAG laser lithotripsy in our institute. Study endpoint was the number of treatments until the patient was stone-free. Patients were classified according to the location of their stones as Group I (distal ureteric stones, 51 patients) and group II (proximal ureteral stones, 37). Group I patients have larger stones as Group II (10.70 mm vs. 8.24 mm, respectively, P = 0.020). RESULTS: Overall stone free rate for both groups was 95.8%. The mean number of procedures for proximal calculi was 1.1 ± 0.1 (1-3) and for distal calculi was 1.0 ± 0.0. The initial treatment was more successful in patients with distal ureteral calculi (100% vs. 82.40%, respectively, P = 0.008). No significant difference in the stone free rate was noticed after the second laser procedure for stones smaller versus larger than 10 mm (100% versus 94.1%, P = 0.13). Overall complication rate was 7.9% (Clavien II und IIIb). Overall and grade-adjusted complication rates were not dependent on the stone location. No laser induced complications were noticed. CONCLUSIONS: The use of the Ho:YAG laser appears to be an adequate tool to disintegrate ureteral calculi independent of primary location. Combination of the semirigid and flexible ureteroscopes as well as the appropriate endourologic tools could likely improve the stone clearance rates for proximal calculi regardless of stone-size.

Encrustation of urologic double pigtail catheters-an ex vivo optical coherence tomography (OCT) study.

This study aims to evaluate whether optical coherence tomography (OCT) using both the surface and the endoluminal technique is feasible to investigate the locations and degree of encrustation process in clinically used ureteral stents. After removal from patients, 14 polyurethane JJ stents were investigated. A fresh JJ served as a control. The external surfaces were examined using an endoscopic surface OCT whereas the intraluminal surfaces were investigated by an endoluminal radial OCT device. The focus was on detection of encrustation or crystalline sedimentation. In 12 female and two male patients, the median indwelling time of the ureteral catheter was 100 days (range, 19-217). Using the endoluminal OCT, the size and grade of intraluminal encrustation could be expressed as a percentage relating to the open lumen of the reference stent. The maximum encrustation observed resulted in a remaining unrestricted lumen of 15-35 % compared to the reference. The luminal reduction caused by encrustation was significantly higher at the proximal end of the ureteral stent as compared to its distal part. The extraluminal OCT investigations facilitated the characterization of extraluminal encrustation. OCT techniques were feasible and facilitated the detection of encrustation of double pigtail catheters on both the extra and intra luminal surface. Quantitative expression of the degree of intraluminal encrustation could be achieved, with the most dense and thickened occurrence of intraluminal incrustation in the upper curl of the JJ stent.

Monitoring the coupling of the lithotripter therapy head with skin during routine shock wave lithotripsy with a surveillance camera.

PURPOSE: With lithotripters today the shock waves are typically transmitted into the body via water filled bellows using coupling gel to make contact with the skin. Usually the coupling zone is not visible to the operator. We investigated coupling quality during routine clinical shock wave lithotripsy and the associated effect on shock wave disintegration efficiency. MATERIALS AND METHODS: During 30 routine shock wave lithotripsy treatments the coupling zone was continuously monitored by a video camera integrated into a DoLi SII lithotripter (Dornier MedTech, Wessling, Germany). However, it was not shown to the blinded operator to resemble the standard clinical situation. We used 3 coupling gels, including LithoClear®, Sonogel® and a custom-made gel of low viscosity. The ratio of air in the relevant coupling area was measured. Lithotripter disintegration efficiency was evaluated by in vitro model stone tests at an air ratio of 0%, 5%, 10% and 20%. RESULTS: Only in 10 of 30 treatments was good coupling achieved with an air ratio of less than 5%. In 8 treatments the ratio was greater than 20%. The best coupling conditions were achieved with low viscosity gel. The mean ± SD number of shock waves needed for complete fragmentation in the model stone tests was 100 ± 4 for bubble-free coupling, and 126 ± 3 for 5%, 151 ± 8 for 10% and 287 ± 5 for 20% air bubbles. CONCLUSIONS: At 20 of 30 shock wave lithotripsy sessions there was imperfect coupling, accompanied by significant loss of disintegration capability. A surveillance camera is useful to monitor and improve coupling.

In vitro investigations of repulsion during laser lithotripsy using a pendulum set-up.

Ureteroscopic laser lithotripsy is a commonly used technique to treat ureteral calculi.The type of energy source used is one of the main influences of retrograd calculi propulsion. Using a momentum pendulum under-water set-up the induced momentum and the initial velocity were investigated. Pulsed laser light from three different clinically available laser systems, including a Ho:YAG laser, a frequency-doubled double-pulse (second harmonic generation, SHG) Nd:YAG laser and a flash-lamp pumped dye (FLPD) laser, were transmitted via flexible fibres of different core diameter to the front of the pendulum sinker. Single pulses at variable pulse energy, according to the clinical laser parameter settings, were applied to the target sinker, thus causing a repulsion-induced deflection which was documented by video recording. The maximum deflection was determined. Solving the differential equation of a pendulum gives the initial velocity, the laser-induced momentum and the efficiency of momentum transfer. The induced deflection as well as the starting velocity of the two short-duration pulsed laser systems (SHG Nd:YAG, FLPD) were similar (s (max) = 2-3.6 cm and v (0) = 150-200 mm/s, respectively), whereas both values were lower using the Ho:YAG laser with a long pulse duration (s (max) = 0.9--1.6 cm and v (0) = 60-105 mm/s, respectively). The momentum I induced by the Ho:YAG laser was only 50% and its transfer efficacy η (Repuls) was reduced to less than 5% of the values of the two short-pulsed laser systems. This investigation clearly showed the variable parts and amounts of repulsion using different pulsed lasers in an objective and reproducible manner. The momentum transfer efficiency could be determined without any physical friction problems. Further investigations are needed to compare stone fragmentation techniques with respect to laser repulsion and its clinical impact.

Single-step percutaneous nephrolithotomy (microperc): the initial clinical report.

PURPOSE: To our knowledge we report the first technical feasibility and safety study of 1-step percutaneous nephrolithotomy using the previously described 4.85Fr all-seeing needle (PolyDiagnost, Pfaffenhofen, Germany). We defined microperc as modified percutaneous nephrolithotomy in which renal access and percutaneous nephrolithotomy are done in 1 step using the all-seeing needle. MATERIALS AND METHODS: Microperc was performed in 10 cases using the 4.85Fr all-seeing needle to achieve collecting system access under direct vision. Percutaneous nephrolithotomy was done through the same 16 gauge needle sheath with a 3-way connector allowing irrigation, and passage of a flexible telescope and a 200 µm holmium:YAG laser fiber. We prospectively analyzed preoperative, intraoperative and postoperative parameters. RESULTS: Mean calculous size was 14.3 mm. Two of the 10 patients were of pediatric age, and 1 each had an ectopic pelvic kidney, chronic kidney disease and obesity. Microperc was feasible in all cases with mean ± SD surgeon visual analog score for access of 3.1 ± 1.2, a mean 1.4 ± 1.0 gm/dl hemoglobin decrease and a mean hospital stay of 2.3 ± 1.2 days. The stone-free rate at 1 month was 88.9%. In 1 patient intraoperative bleeding obscured vision, requiring conversion to mini percutaneous nephrolithotomy. There were no postoperative complications and no auxiliary procedures were required. CONCLUSIONS: Microperc is technically feasible, safe and efficacious for small volume renal calculous disease. Further clinical studies and direct comparison with available modalities are required to define the place of microperc in the treatment of nonbulky renal urolithiasis.

Does comprehension (sometimes) go wrong for noncanonical sentences?

This article addresses the question of whether the human parsing mechanism (HPM) derives sentence meaning always from representations that are computed algorithmically or whether the HPM sometimes resorts to non-algorithmic strategies that may result in misinterpretations. Misinterpretation effects for noncanonical sentences, such as passives, constitute important evidence in favour of models allowing for nonveridical representations. However, it is unclear whether these effects reflect errors in the mapping of form to meaning, or difficulties specific to the procedure used to test comprehension. We report two experiments combining two different comprehension tasks to address these alternative possibilities. In Experiment 1, participants first judged the plausibility of canonical and noncanonical sentences and then named the agent or patient of the sentence. In Experiment 2, the order of the two tasks was reversed. Both tasks require the correct identification of agent or patient/theme, but differ regarding the complexity of operations required to complete the task successfully. In both experiments, participants made a substantial number of errors with agent/patient naming, even when they had correctly assessed sentence plausibility. We conclude that misinterpretation effects do not indicate parsing errors and therefore cannot serve as evidence for non-algorithmic processing. Our results support models of the HPM that assume algorithmic processing only.

Impact of previous mesh hernia repair on the performance of open radical prostatectomy - complications and functional outcome.

OBJECTIVES: To determine the impact of previous inguinal mesh hernia repair (IMHR) on the performance of subsequent open radical retropubic prostatectomy (ORRP). PATIENTS AND METHODS: A total of 1466 patients underwent ORRP for clinically localized prostate cancer from 2004 to 2008; 51 patients (3.5%) presented with a history of IMHR. Body-mass index (BMI), perioperative blood loss (PBL), operating time (OT), performance of pelvic lymph node dissection (PLD), positive resection-margins (R1), continence and potency between the groups were analysed using Mann-Whitney U and χ(2) tests. RESULTS: Fifty-one patients with previous IMHR were compared with 1466 patients without previous mesh implantation (nMI) who underwent ORRP. Mean age was 66.8 years and mean BMI 25.7. No statistically difference in the mean OT (68 vs 72 min, P= 0.112), mean PBL (167 vs 156 ml, P= 0.089) or R1 was observed in the pT2-stage tumors (3% vs 9.7%, P= 0.197), or in the pT3-stage tumors (16% vs 21%, P= 0.386). After 3 months 85% showed full continence in the nMI group vs 83.9% MI group (P= 0.864) and after 12 months 94.5% of the nMI patients vs 97.6% with mesh (P= 0.610). The IIEF-5 score after 3 months showed a median of 9.0 in the MI group and 4.5 in the nMI group (P= 0.116) and after 12 months 12.0 in the MI group and 9.0 in the nMI group (P= 0.511). PLD was significantly more feasible in patients that underwent only unilateral IMHR compared with bilateral IMHR (96% vs 40%, P= 0.001) and significantly less feasible if previous IMHR was operated laparoscopically than with an open access (47% vs 88%, P= 0.014). CONCLUSION: No impairment of perioperative variables or functional outcome during ORRP was observed in patients with IMHR. PLD could be performed in a significantly fewer patients who underwent bilateral IMHR or laparoscopic IMHR.

Organ-preserving neodymium-yttrium-aluminium-garnet laser therapy for penile carcinoma: a long-term follow-up.

OBJECTIVE: To retrospectively analyse the long-term follow-up of 54 patients treated with organ-preserving laser therapy for penile carcinoma, as such therapy provides excellent cosmetic and functional results, but recurrence rates are high, which might impair the oncological outcome and worsen tumour-related survival. PATIENTS AND METHODS: Between 1979 and 2008, 54 patients with penile carcinoma were treated with the neodymium-doped yttrium-aluminium-garnet (Nd:YAG) laser at our institution; 11 were classified as having carcinoma in situ (Tis), 39 as T1 and four as T2. RESULTS: There was local recurrence in 16 patients (42%); the mean (range) time to local recurrence was 53 (9-132) months. In half the patients the time to local recurrence was >53 months, with the latest recurrence at 132 months after initial therapy of primary tumour. There was no statistically significant difference in recurrence rates with Tis or invasive penile carcinoma. In lymph-node-negative patients at initial presentation, there were no newly developed positive lymph nodes during the follow-up. CONCLUSIONS: Organ-preserving laser therapy showed a relatively high recurrence rate in patients with a long-term follow up, but the oncological outcome and survival were not compromised by local recurrence. Therefore, laser therapy appears to be appropriate for treating premalignant lesions and early stages of penile carcinoma. Patients should be informed about the potential for late recurrence.