Michael K. Louie

The percutaneous nephrolithotomy global study: classification of complications.

PURPOSE This study evaluated postoperative complications of percutaneous nephrolithotomy (PCNL) and the influence of selected factors on the risk of complications using the Clinical Research Office of the Endourological Society (CROES) PCNL Global Study database. PATIENTS AND METHODS The CROES PCNL Global Study collected prospective data for consecutive patients who were treated with PCNL at centers around the world for 1 year. Complications were evaluated by the modified Clavien classification system. RESULTS Of 5724 patients with Clavien scores, 1175 (20.5%) patients experienced one or more complications. The most frequent complications were fever and bleeding. Urinary leakage, hydrothorax, hematuria, urinary tract infection, pelvic perforation, and urinary fistula also occurred in ≥20 patients in each group. The majority of complications (n=634, 54.0%) were classified as Clavien grade I. Two patients died in the postoperative period. The largest absolute increases in mean Clavien score were associated with American Society of Anesthesiologists (ASA) physical status classification IV (0.75) or III (0.34), anticoagulant medication use (0.29), positive microbiologic culture from urine (0.24), and the presence of concurrent cardiovascular disease (0.15). Multivariate regression analysis revealed that operative time and ASA score were significant predictors of higher mean Clavien scores. CONCLUSION The majority of complications after PCNL are minor. Longer operative time and higher ASA scores are associated with the risk of more severe postoperative complications in PCNL.

Rapid Communication: Robot-Assisted NOTES Nephrectomy: Initial Report

BACKGROUND AND PURPOSE Natural Orifice Transluminal Endoscopic Surgery (NOTES) using the daVinci robot (Intuitive Surgical, Sunnyvale, CA) has never been applied to urologic surgery. Here we present our initial experience with a combined transvaginal and transcolonic, single-port, robot-assisted NOTES nephrectomy. METHODS An acute experiment was performed in a female farm pig. A single 12-mm trocar was placed in the midline, and two 12-mm standard laparoscopic ports were placed into the abdomen via the vagina and the colon. The robotic ports were then telescoped into the 12-mm ports, and the daVinci S robot was docked. Dissection was performed using the Hot Shears and the ProGrasp instruments. The robotic camera was placed via the midline port and held by an assistant. Using the 12-mm transvaginal port, the renal artery and vein were divided separately with a vascular Endo GIA (US Surgical, Norwalk, CT) stapler. The kidney was placed into a 10-mm entrapment sack and removed intact via the vagina. RESULTS Total operative time was 150 minutes. Estimated blood loss was less than 50 mL. No intraoperative complications occurred. CONCLUSION A robot-assisted NOTES nephrectomy was accomplished in a porcine model using the daVinci S robot. Additional testing on survival animals is necessary to further explore this approach.

Long-Term Impact of a Robot Assisted Laparoscopic Prostatectomy Mini Fellowship Training Program on Postgraduate Urological Practice Patterns

PURPOSE Robot assisted laparoscopic prostatectomy has stimulated a great deal of interest among urologists. We evaluated whether a mini fellowship for robot assisted laparoscopic prostatectomy would enable postgraduate urologists to incorporate this new procedure into clinical practice. MATERIALS AND METHODS From July 2003 to July 2006, 47 urologists participated in the robot assisted laparoscopic prostatectomy mini fellowship program. The 5-day course had a 1:2 faculty-to-attendee ratio. The curriculum included lectures, tutorials, surgical case observation, and inanimate, animate and cadaveric robotic skill training. Questionnaires assessing practice patterns 1, 2 and 3 years after the mini fellowship program were analyzed. RESULTS One, 2 and 3 years after the program the response rate to the questionnaires was 89% (42 of 47 participants), 91% (32 of 35) and 88% (21 of 24), respectively. The percent of participants performing robot assisted laparoscopic prostatectomy in years 1 to 3 after the mini fellowship was 78% (33 of 42), 78% (25 of 32) and 86% (18 of 21), respectively. Among the surgeons performing the procedure there was a progressive increase in the number of cases each year with increasing time since the mini fellowship training. In the 3 attendees not performing the procedure 3 years after the mini fellowship training the reasons were lack of a robot, other partners performing it and a feeling of insufficient training to incorporate the procedure into clinical practice in 1 each. One, 2 and 3 years following the mini fellowship training program 83%, 84% and 90% of partnered attendees were performing robot assisted laparoscopic prostatectomy, while only 67%, 56% and 78% of solo attendees, respectively, were performing it at the same followup years. CONCLUSIONS An intensive, dedicated 5-day educational course focused on learning robot assisted laparoscopic prostatectomy enabled most participants to successfully incorporate and maintain this procedure in clinical practice in the short term and long term.

Does imaging modality used for percutaneous renal access make a difference? A matched case analysis.

OBJECTIVE To assess perioperative outcomes of percutaneous nephrolithotomy (PCNL) using ultrasound or fluoroscopic guidance for percutaneous access. METHODS A prospectively collected international Clinical Research Office of the Endourological Society (CROES) database containing 5806 patients treated with PCNL was used for the study. Patients were divided into two groups based on the methods of percutaneous access: ultrasound versus fluoroscopy. Patient characteristics, operative data, and postoperative outcomes were compared. RESULTS Percutaneous access was obtained using ultrasound guidance only in 453 patients (13.7%) and fluoroscopic guidance only in 2853 patients (86.3%). Comparisons were performed on a matched sample with 453 patients in each group. Frequency and pattern of Clavien complications did not differ between groups (p=0.333). However, postoperative hemorrhage and transfusions were significantly higher in the fluoroscopy group: 6.0 v 13.1% (p=0.001) and 3.8 v 11.1% (p=0.001), respectively. The mean access sheath size was significantly greater in the fluoroscopy group (22.6 v 29.5F; p<0.001). Multivariate analysis showed that when compared with an access sheath ≤ 18F, larger access sheaths of 24-26F were associated with 3.04 times increased odds of bleeding and access sheaths of 27-30F were associated with 4.91 times increased odds of bleeding (p<0.05). Multiple renal punctures were associated with a 2.6 odds of bleeding. There were no significant differences in stone-free rates classified by the imaging method used to check treatment success. However, mean hospitalization was significantly longer in the ultrasound group (5.3 v 3.5 days; p<0.001). CONCLUSIONS On univariate analysis, fluoroscopic-guided percutaneous access was found to be associated with a higher incidence of hemorrhage. However, on multivariate analysis, this was found to be related to a greater access sheath size (≥ 27F) and multiple punctures. Prospective randomized trials are needed to clarify this issue.

Preliminary Study of Virtual Reality and Model Simulation for Learning Laparoscopic Suturing Skills

PURPOSE Repetitive practice of laparoscopic suturing and knot tying can facilitate surgeon proficiency in performing this reconstructive technique. We compared a silicone model and pelvic trainer to a virtual reality simulator in the learning of laparoscopic suturing and knot tying by laparoscopically naïve medical students, and evaluated the subsequent performance of porcine laparoscopic cystorrhaphy. MATERIALS AND METHODS A total of 20 medical students underwent a 1-hour didactic session with video demonstration of laparoscopic suturing and knot tying by an expert laparoscopic surgeon. The students were randomized to a pelvic trainer (10) or virtual reality simulator (10) for a minimum of 2 hours of laparoscopic suturing and knot tying training. Within 1 week of the training session the medical students performed laparoscopic closure of a 2 cm cystotomy in a porcine model. Objective structured assessment of technical skills for laparoscopic cystorrhaphy was performed at the procedure by laparoscopic surgeons blinded to the medical student training format. A video of the procedure was evaluated with an objective structured assessment of technical skills by an expert laparoscopic surgeon blinded to medical student identity and training format. The medical students completed an evaluation questionnaire regarding the training format after the laparoscopic cystorrhaphy. RESULTS All students were able to complete the laparoscopic cystorrhaphy. There was no difference between the pelvic trainer and virtual reality groups in mean +/- SD time to perform the porcine cystorrhaphy at 40 +/- 15 vs 41 +/- 10 minutes (p = 0.87) or the objective structured assessment of technical skills score of 8.8 +/- 2.3 vs 8.2 +/- 2.2 (p = 0.24), respectively. Bladder leak occurred in 3 (30%) of the pelvic trainer trained and 6 (60%) of the virtual reality trained medical student laparoscopic cystorrhaphy procedures (Fisher exact test p = 0.37). The only significant difference between the 2 groups was that 4 virtual reality trained medical students considered the training session too short compared to none of those trained on the pelvic trainer (p = 0.04). CONCLUSIONS There is no significant difference between the pelvic trainer and virtual reality trained medical students in proficiency to perform laparoscopic cystorrhaphy in a pig model, although both groups require considerably more training before performing this procedure clinically. The pelvic trainer training may be more user-friendly for the novice surgeon to begin learning these challenging laparoscopic skills.

Robotic Pyeloplasty: The University of California-Irvine Experience

PURPOSE For the treatment of ureteropelvic junction obstruction laparoscopic dismembered pyeloplasty and open pyeloplasty have similar outcomes. We present our experience with robot assisted laparoscopic dismembered pyeloplasty. MATERIALS AND METHODS We retrospectively reviewed all adult robot assisted laparoscopic dismembered pyeloplasties performed at our institution between November 2002 and July 2009. Preoperative evaluation included abdominal computerized tomography angiogram to assess for crossing vessels and diuretic renal scan to quantify the degree of obstruction. Followup with diuretic renal scan and a patient pain analog scale was performed 3, 6 and 12 months after surgery. If the study was normal at 12 months, the patient was followed with ultrasound of the kidneys and bladder to look for ureteral jets. Absent ureteral jets, worsening hydronephrosis or patient complaint of pain necessitated repeat diuretic renogram. RESULTS A total of 61 robot assisted laparoscopic dismembered pyeloplasties were performed in 21 men and 40 women. Followup was available for 57 patients with an average ± SD age of 35 ± 16 years and average followup of 18 ± 15 months. Mean operative time was 335 ± 88 minutes and estimated blood loss was 61 ± 48 ml. Average hospitalization time was 2 ± 0.9 days and the average postoperative analgesia requirement was 13 ± 9.6 mg morphine sulfate equivalents. The overall success rate was 81% based on a normal diuretic renogram and lack of pain using a validated pain scale. There were 3 grade III Clavien complications for a 4.9% major complication rate. CONCLUSIONS Robot assisted laparoscopic dismembered pyeloplasty is a feasible technique for ureteropelvic junction reconstruction. When measured by the more stringent application of diuretic renography and analog pain scales, the success rate for ureteropelvic junction obstruction management appears similar to that of open or standard laparoscopic approaches.

Prospective randomized trial of three different methods of nephrostomy tract closure after percutaneous nephrolithotripsy

Study Type – Therapy (RCT) 
Level of Evidence 1b

In Vitro, Ex Vivo and In Vivo Isotherms for Renal Cryotherapy

PURPOSE Preoperative planning for renal cryotherapy is based on isotherms established in gel. We replicated gel isotherms and correlated them with ex vivo and in vivo isotherms in a porcine model. MATERIALS AND METHODS PERC-17 CryoProbes (1.7 mm) and IceRods (1.47 mm) underwent trials in gel, ex vivo and in vivo porcine kidneys. Temperatures were recorded at 13 predetermined locations with multipoint thermal sensors. RESULTS At the cryoprobe temperatures were not significantly different along the probe in any medium for either system (p = 0.0947 to 0.9609). However, away from the probe ex vivo and in vivo trials showed warmer temperatures toward the cryoprobe tip for each system (p = 0.0003 to 0.2141). Mean +/- SE temperature 5 mm distal to the cryoprobe tip in vivo was 19.2C +/- 16.1C for CryoProbes and 27.3C +/- 11.2C for IceRods. Temperatures were consistently colder with CryoProbes than with IceRods in gel (p <0.00005), ex vivo (p <0.00005) and in vivo (p = 0.0014). At almost all sites temperatures were significantly colder in gel and in ex vivo kidney than in in vivo kidney for CryoProbes (p = 0.0107 and 0.0008, respectively) and for IceRods (each p <0.00005). CONCLUSIONS Gel and ex vivo isotherms do not predict the in vivo pattern of freezing. Thus, they should not be used for preoperative planning. The cryoprobe should be passed 5 mm beyond the tumor border to achieve suitably cold temperatures. Multipoint thermal sensor probes are recommended to record actual temperature during renal cryotherapy.

Differences in Grip Forces Among Various Robotic Instruments and da Vinci Surgical Platforms

INTRODUCTION The da Vinci surgical platform is becoming increasingly available and utilized. Due to the lack of haptic feedback, visual cues are necessary to estimate grip forces and tissue tensions during surgery. We directly measured the grip forces of robotic EndoWrist instruments using the three available da Vinci robotic surgical platforms. METHODS Robotic instruments were tested in the da Vinci S, Si, and Standard systems. A load cell was placed in a housing unit that allowed for measurement of the grip forces applied by the tip of each robotic instrument. Each instrument was tested six times, and all data were analyzed using Students t-tests or analysis of variance when appropriate. RESULTS Slight differences in grip force were seen when the instrument was tested through 2 degrees of freedom at the tip (p = 0.02, analysis of variance) and when comparing a new instrument to an older instrument (p = 0.001 at the neutral position). There was no statistical difference in grip force between the left and right robotic arms. There was a broad range of grip forces between the various robotic instruments. The lowest grip force was registered in the double fenestrated grasper (2.26 ± 0.15 N), whereas the highest was seen in the Hem-o-lok clip applier (39.92 ± 0.89 N). In comparison to the S and Si, the Standard platform appeared to have significantly higher grip forces. CONCLUSION Different grip forces were observed among the various robotic instruments commonly used during urologic surgery and between the Standard and the S and Si platforms.

Impact of a Laparoscopic Renal Surgery Mini-Fellowship Program on Postgraduate Urologist Practice Patterns at 3-Year Followup

PURPOSE To assist practicing urologists incorporate laparoscopic renal surgery into their practice we established a 5-day mini-fellowship program with a mentor, preceptor and a potential proctor at our institution. We report the impact of our mini-fellowship program at 3-year followup. MATERIALS AND METHODS A total of 106 urologists underwent laparoscopic ablative (44) or laparoscopic reconstructive (62) renal surgery training. The 1:2 teacher-to-attendee experience included tutorial sessions, hands-on inanimate and animate skills training, and clinical case observations. Participants were asked to complete a detailed questionnaire on laparoscopic practice patterns 1, 2 and 3 years after the mini-fellowship. RESULTS The questionnaire response rate at 1 to 3 years was 77%, 65% and 68%, respectively. Of responders 72%, 71% and 71% performed laparoscopic renal surgery at 1 to 3 years, respectively. Of the 106 participants 32 (39%) had previous laparoscopic experience, including 78% who responded to the questionnaire at 3 years. Of those surgeons there was an increase in the practice of laparoscopic radical nephrectomy (88% vs 72%), nephroureterectomy (56% vs 13%), pyeloplasty (40% vs 6%) and partial nephrectomy (32% vs 6%) at 3 years. Of the 106 participants 74 (70%) were laparoscopy naïve, including 48 (65%) who responded to the questionnaire at 3 years. The take rate in this group was 76%, 52%, 34% and 23% for laparoscopic radical nephrectomy, nephroureterectomy, pyeloplasty and partial nephrectomy, respectively. Of the participants 90% indicated that they would recommend this training to a colleague. CONCLUSIONS An intensive 5-day laparoscopic ablative and reconstructive renal surgery course enabled postgraduate urologists to effectively introduce and expand the volume and breadth of their laparoscopic renal surgery practice.