Calyx Puncture Research Articles

Comparative Evaluation of Upper Pole and Non-Upper Pole Puncture Techniques in Percutaneous Nephrolithotomy (PCNL): A Retrospective Analysis of Efficacy and Safety Parameters

Background: Percutaneous nephrolithotomy (PCNL) is a critical intervention in the management of large renal calculi, with the choice of calyx puncture technique impacting the efficacy and safety of the procedure. While the upper pole approach is associated with better visualization and stone clearance, it is used with caution due to a perceived increase in complication rates. Objective: This study aimed to compare the upper pole calyx puncture technique's efficacy and safety with that of the non-upper pole (middle and lower) puncture techniques in PCNL. Methods: A retrospective analysis was conducted on 173 patients who underwent PCNL at the Urology and Transplant Unit A of The Institute of Kidney Diseases in Peshawar from January 2017 to December 2020. Data on demographics, stone characteristics, perioperative findings, and postoperative outcomes were collected. Statistical significance was determined using Chi-square tests with SPSS version 25. Results: The average stone size was 21.38 mm (±11.2 mm) overall, with the upper pole group presenting a smaller average size of 19.8 mm (±7.6 mm) compared to 21.55 mm (±10.8 mm) for the non-upper pole group (p=0.032). Pre-operative hemoglobin levels were slightly lower in the upper pole group (12.5 ± 1.8 mg/dl) than in the non-upper pole group (12.9 ± 1.8 mg/dl, p=0.007). Complete clearance rates were comparable between groups. Post-operative blood transfusion was required more frequently in the non-upper pole group (12.1%, n=12) versus the upper pole group (4.0%, n=3, p=0.04). Conclusion: The upper pole approach in PCNL may afford a higher rate of stone clearance and reduced operative times with acceptable safety when compared to non-upper pole approaches. The selection of puncture technique should be tailored to individual patient anatomy and stone characteristics, with consideration given to the surgeon's experience and skill.

Prone Split-Leg vs Galdakao-Modified Supine Valdivia Position During Endoscopic Combined Intrarenal Surgery: A Noninferiority Design Randomized Controlled Trial

Purpose: Endoscopic combined intrarenal surgery (ECIRS) combines percutaneous nephrolithotomy and ureteroscopy. This procedure has become common with the development of the prone split-leg (PRO) and Galdakao-modified supine Valdivia (GMSV) positions. In this study, we evaluated the surgical outcomes of these positions during ECIRS. Materials and Methods: A noninferior randomized controlled trial was performed in accordance with the Consolidated Standards of Reporting Trials. The eligibility criteria were age 20 to 80 years and presence of > 15-mm renal and/or ureteral stones. They were assigned to the PRO or GMSV groups and underwent ECIRS in the PRO or GMSV position, respectively. The primary outcome was stone-free rate (SFR) 3 months after surgery. The secondary outcomes were surgical outcomes—surgery time, percutaneous access time, and complication rate. A noninferiority margin of 30% was used. Results: Eighty-six patients (46 in the PRO group and 43 in the GMSV group) were analyzed. The SFR was 91.3% and 90.7% in the PRO and GMSV groups, respectively. No between-group differences were observed regarding the overall complication rates. Percutaneous access time was longer in the PRO group than in the GMSV group for upper calyx punctures, whereas surgery and percutaneous access times were shorter in the PRO group for those with a middle calyx puncture. Conclusions: Surgical position did not affect the success rates. There was no difference in complications between the groups, except for perinephric hematoma formation.

Comparison of stone clearance rate based on upper, middle, or lower calyx puncture in Mini Percutaneous Nephrolithotomy (mPCNL)

Introduction: PCNL is the most common surgical technique used for the management of renal stones, particularly for those with more than 2 cm stones. The aim of this study is to identify which kidney calyx—upper, middle, or lower—when punctured achieves the highest stone clearance rate. Methods: This was a prospective non-randomised study performed in department of urology, KIST medical college from September 1, 2021 to November 16, 2022. Patients who underwent PCNL were evaluated with detailed history, examination, and investigation. All the patients who fulfill the inclusion criteria during study period were included in the study. After preoperative investigation PCNL was done according to standard protocol. Perioperative complication recorded in Performa. Stone-free status was checked after 2 months of surgery with ultrasonography. Results: 100 patients were included in this study among which 59 were male. The mean age of patients was 33.35 years [range 18-65 years]. Upper, middle and lower pole puncture was done in 23%, 33% and 44% patients respectively. The mean stone burden of the patient was 380.680 mm2. The average time for surgery according to access was 67.34 mins, 63.12mins, and 64.07 mins for the upper calyx, mid-calyx and for the lower calyx respectively. 84.33% of patients had complete stone clearance after 2 months in the USG examination. 91.3% [21] had stone clearance when approached through the upper calyx. It was 87.8%[29] by mid calyx and 75%[33] by lower calyx. Upper calyx puncture had statistical significance in stone clearance rate [P=0.43, P=0.021, P=0.002]. 11 had CRIF ≤4mm stone in PCS, and the remaining 6 had residual stone >4mm. In our study, thoracic complications were significantly higher in upper calyx puncture 8[30.4%, 8[24.24% in the middle calyx, and 3[6.8%] in lower calyx [P=0.02, P=0.98, P=0.03] respectively. Conclusion: Upper calyceal puncture can produce the highest stone clearance rate, but it has been associated with significant postoperative morbidity, particularly in the chest. Lower calyx punctures have less intraoperative and postoperative morbidity, but their stone removal rates are lower than those of other procedures. Therefore, the balance between stone clearance rate and morbidity has been achieved using middle calyx puncture.

Presence of a Novel Anatomical Structure May Cause Bleeding When Using the Calyx Access in Mini-Percutaneous Nephrolithotomy.

BackgroundFused renal pyramid (FRP) is a kidney anatomical structure which was first identified by us. The vascular anatomy of FRP exhibits different from that of the normal renal pyramid (NRP), manifested by the distribution of the ectopic interlobar arteries in FRP. In this study, we analyzed the effect of FRPs on bleeding when using calyx access in mini-percutaneous nephrolithotomy (PCNL).Patients and MethodsOverall, 633 patients who underwent ultrasound-guided single-tract mini-PCNL were divided into two groups according to the puncture method used: in group A, puncture was performed through the axial direction of the renal calyx, the line from the apex of the fornix to the center of the neck plane under B-mode ultrasound guidance; and in group B, Doppler ultrasound-guided axillary puncture through calyces corresponding to NRPs when the plane of renal column blood vessels on both sides was selected or calyx puncture through the hypovascular area of the FRPs. Relevant demographic and clinical data were retrospectively analyzed.ResultsThe two groups exhibited similar baseline characteristics. No significant differences were found in hemoglobin reduction, puncture site, tract size, postoperative creatinine level, or stone-free rate between the two groups (P > 0.05). Blood transfusion and embolization rates in group B were significantly lower than those in group A (P = 0.03 and 0.045, respectively). No differences were found between the two groups in terms of persistent pain, hydrothorax, fever, subcapsular hematoma, and urosepsis (P > 0.05). The overall complication rate was not significantly different between the two groups (P = 0.505).ConclusionsFRP is a non-negligible anatomical structure that may cause hemorrhage when using calyx access. Doppler ultrasound can identify ectopic blood vessels in FRPs to reduce bleeding during calyx access in mini-PCNL procedures.

Prone versus supine percutaneous nephrolithotomy: a systematic review and meta-analysis of current literature.

Percutaneous nephrolithotomy (PNL) can be performed either in prone or supine position. This study aimed at gathering together randomized controlled trials (RCTs) comparing efficacy and safety between prone and supine PNL. Systematic review of literature was conducted using the Scopus, Medline and Web of Science databases. Study selection, data extraction and quality assessment were independently assessed by two authors. Meta-analysis was performed with Review Manager 5.3. Sensitivity analyses were performed to exclude studies with high risk of bias. Pooled data from 12 studies including 1290 patients were available for analysis. Only one study was found to have overall low risk of bias. Significantly shorter operative time was found in favor of supine PNL (mean difference 13 minutes, 95% confidence interval [CI]: 3.4-22.7; P<0.01). Stone-free rate (SFR)≥14 days after surgery was significantly higher in prone PNL (odds ratio [OR]=2.15, 95% CI: 1.07-4.34; P=0.03). Significantly higher fever rate was found in prone PNL (OR=1.60, 95% CI: 1.03-2.47; P=0.04). Overall SFR, hospital stay length, complications rate, transfusions rate and blood loss, as well as non-lower calyx puncture rate, puncture attempts and tubeless intervention rate did not differ between prone and supine PNL (P>0.05). Efficacy of PNL seems balanced between prone and supine position, with comparable overall SFR and shorter operative time in favor of supine PNL. Safety of PNL appears in favor of supine PNL, with lower fever rate. Because of study heterogeneity and possible risks of outcome bias, results from this study should be interpreted with caution. Altogether, both prone and supine PNL account for appropriate therapy options.

V05 - Monoplane fluoroscopy simplified technique of percutaneous calyx puncture

V05 - Monoplane fluoroscopy simplified technique of percutaneous calyx puncture

Lateral percutaneous nephrolithotomy: A safe and effective surgical approach.

Introduction:Percutaneous nephrolithotomy (PCNL) is traditionally performed with the patient in the prone position for large renal calculi. However, anesthetic limitations exist with the prone position. Similarly, the supine position is associated with poorer ergonomics due to the awkward downward position of the renal tract, a smaller window for percutaneous puncture, and a higher risk of anterior calyx puncture. This study aimed to demonstrate the feasibility and safety of lateral-PCNL in managing large renal calculi without the disadvantages of prone and supine positions.Methods:Retrospectively, 347 lateral-PCNL cases performed from July 2001 to July 2015 were examined. the patient's thorax, abdomen, and pelvis were positioned over a bridge perpendicular to a “broken” table, creating an extended lumbodorsal space. The procedure was evaluated in terms of stone clearance at 3 months’ postprocedure, operative time, and complications.Results:Primary stone clearance was achieved in 82.7% of patients. The mean operating time was 97 min. The average time taken to establish the tract and mean radiation time were 4.5 min and 6.93 min, respectively. In total, 2.3% of patients required postoperative transfusion, and 13.5% of patients had postoperative fever. There was one case of hydrothorax, but no bowel perforation.Conclusions:Our lateral-PCNL technique allows for effective stone clearance due to good stone ergonomics and it should be considered as a safe alternative even in the most routine procedures.

Impact of patient position on the outcomes of percutaneous neprolithotomy for complex kidney stones.

ABSTRACTPurpose:To evaluate the impact of the patient position on the outcomes of PCNL among patients with complex renal stones.Material and Methods:From July 2011 to July 2014, we collected prospective data of consecutive patients who underwent PCNL. We included all patients with complex stones (Guy's Stone Score 3 or 4 (GSS) based on a CT scan) and divided them based on the position used during PCNL (prone or supine). The variables analyzed were gender, age, body mass index, ASA score, stone diameter, GSS, number of punctures, calyx puncture site, intercostal access and patient positioning. Complications were graded according to the modified-Clavien Classification. Success was considered if fragments ≤ 4mm were observed on the first postoperative day CT scan.Results:We analyzed 240 (46.4%) of 517 PCNL performed during the study period that were classified as GGS 3-4. Regarding patient positions, 21.2% were prone and 79.8% were supine. Both groups were comparable, although intercostal access was more common in prone cases (25.5% vs 10.5%; p=0.01). The success rates, complications, blood transfusions and surgical times were similar for both groups; however, there were significantly more visceral injuries (10.3% vs 2.6%; p=0.046) and sepsis (7.8% vs 2.1%; p=0.042) in prone cases.Conclusion:Supine or prone position were equally suitable for PCNL with complex stones and did not impact the success rates. However, supine position was associated with fewer sepsis cases and visceral injuries.

MP75-04 THE EFFECT OF STONE PREVENTION COUNSELING AT THE INITIAL CONSULTAION ON 24-HOUR URINE COLLECTION RESULTS (“CLINIC EFFECT”)

METHODS: We performed a retrospective analysis of our prospective database of consecutive patients that underwent to PCNL between July 2011 and July 2014. The variables analyzed were gender, age, body mass index (BMI), ASA score, stone diameter, Guy’s Stone Score (GSS), number of punctures, calyx puncture site, supracostal access and patient positioning. Complex cases were defined as GSS 3 or 4 based on the preoperative CT scan analysis. Complications were graded according to the modified Clavien Classification and Clavien >1⁄43 were considered as major complications. Success was considered as fragments <1⁄44 mm on the first post-operative day (POD1) on CT scan. The tests used in the univariate analyzes were chi-square and Fisher Exact test for categorical measures and Student’s t-test for independent samples continuous parameters. We used a 0.05 significance level. RESULTS: Of the 517 PCNL performed, 240 (46.4%) with GGS 3 or 4 were included in the study. Regarding patient position, 21.2% were in prone position and 79.8% were in supine position (80% in complete supine position, 6.8% in classic Valdivia and 13.1% in Galdakao position). Both groups were similar according mean age, BMI, gender, ASA Score, stone diameter, number of punctures. Supracostal access was necessary in 25.5% of the cases in ventral position against 10.5% in supine position (p1⁄40.01) (Table 1). The success rates, major Clavien complications, blood transfusions and surgical time were not different between the groups (Table 2). CONCLUSIONS: Supine or prone positions were equally suitable for PCNL of complex stones and did not impact the outcomes. The choice of the patient position should be driven by the surgeon’s preference.

MP30-16 PROGNOSTIC FACTORS OF POSTOPERATIVE COMPLICATIONS IN PERCUTANEOUS NEPHROLITHOTOMY

You have accessJournal of UrologyStone Disease: Surgical Therapy III1 Apr 2015MP30-16 PROGNOSTIC FACTORS OF POSTOPERATIVE COMPLICATIONS IN PERCUTANEOUS NEPHROLITHOTOMY Fabio C. Vicentini, Carlos H. Watanabe-Silva, Vinicius Meneguete, Rodrigo Perrela, Claudio B. Murta, and Joaquim F.A. Claro Fabio C. VicentiniFabio C. Vicentini More articles by this author , Carlos H. Watanabe-SilvaCarlos H. Watanabe-Silva More articles by this author , Vinicius MenegueteVinicius Meneguete More articles by this author , Rodrigo PerrelaRodrigo Perrela More articles by this author , Claudio B. MurtaClaudio B. Murta More articles by this author , and Joaquim F.A. ClaroJoaquim F.A. Claro More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.598AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for large kidney stones but there are concerns regarding the complication rates. Our aim is to evaluate the peri-operatory factors associated with complications after PCNL. METHODS We performed a retrospective chart review of a prospective database of patients who underwent PCNL between July 2011 and July 2014. Preoperative and postoperative factors, such as age, body mass index (BMI), surgical risk, stone complexity (Guy's Stone Score - GSS), access calyx, patient positioning, blood transfusion and surgical time were evaluated as predictors of complications. All complications were graded according to the Clavien Classification. The tests used in the univariate analyzes were chi-square and Fisher Exact test for categorical measures and the Student t test for continuous measures. For the multivariate analysis we used logistic regression. RESULTS A total of 468 patients were included in the study and 517 PCNL were performed. The mean age was 48.3±12.8 years, mean BMI of 27.3±5.0 and 57.8% were female. Of these, 82% underwent to PCNL in supine position and 18% in the prone position. According to GGS, 24.8% were GGS1, 28.6% GSS2, 33.8% GSS3 and GSS4 12.8%. Most punctures were on lower and middle calyx (65.8% and 24.8% respectively) and 9.3% of the punctures were supracostal. Mean surgical time 114.6±52.78 min. The success rate (fragments ≤4mm) at POD 1 on CT scan was 55.1% The overall complication rate was 18.7%. According to the modified Clavien Classification System, 5.3% Clavien I, 6.7% Clavien II, 2.0% Clavien IIIa, 2.3% Clavien IIIB, 1.6% Clavien IVa, 0.4% Clavien IVB and 0.4% Clavien V. The transfusion rate was 6.0%. On univariate analysis, the number of accesses, supracostal puncture, upper calyx puncture and higher GSS were predictors of Clavien≥3 (major complications). On multivariate analysis, GSS and upper calyx puncture were the only predictors statistically significant for post-operative complications Clavien ≥3. GSS III and IV increased risk for high grade Clavien compared to GSS I and II (OR 2.52; CI95% 1.21-5.52) and also upper pole access compared to inferior pole access (OR 4.85; CI95%1.46-13.92). Moreover, prone position (OR 2.53; CI95%1.0-6.08), number of punctures (OR 6.11 CI95%1.58-24.04) and high GSS (OR3.01 CI1.19-8.6) were associated with blood transfusions on multivariate analysis. CONCLUSIONS The number of punctures, supracostal access, high GSS and prone position were factors associated with major complications and blood transfusions after PCNL. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e353 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Fabio C. Vicentini More articles by this author Carlos H. Watanabe-Silva More articles by this author Vinicius Meneguete More articles by this author Rodrigo Perrela More articles by this author Claudio B. Murta More articles by this author Joaquim F.A. Claro More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

MP30-19 IMPACT OF THE GUY'S STONE SCORE ON SUCESS RATES FOR PERCUTANEOUS NEPHROLITHOTOMY

You have accessJournal of UrologyStone Disease: Surgical Therapy III1 Apr 2015MP30-19 IMPACT OF THE GUY'S STONE SCORE ON SUCESS RATES FOR PERCUTANEOUS NEPHROLITHOTOMY Fabio C. Vicentini, Carlos Watanabe-Silva, Thiago A.C. Ferreira, Claudio B. Murta, and Joaquim F.A. Claro Fabio C. VicentiniFabio C. Vicentini More articles by this author , Carlos Watanabe-SilvaCarlos Watanabe-Silva More articles by this author , Thiago A.C. FerreiraThiago A.C. Ferreira More articles by this author , Claudio B. MurtaClaudio B. Murta More articles by this author , and Joaquim F.A. ClaroJoaquim F.A. Claro More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.601AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for large kidney stones. The aim of the study was to evaluate which variables impact the success rates of PCNL. METHODS We performed a prospective study of consecutive patients that underwent to PCNL between July 2011 and July 2014. The variables analyzed were gender, age, body mass index (BMI), ASA score, stone diameter, Guy's Stone Score (GSS), number of punctures, calyx puncture site, supracostal access and patient positioning. Complications were graded according to the modified Clavien Classification. Success was considered as fragments ≤4 mm on the first post-operative day (POD1) on CT scan. The tests used in the univariate analyzes were chi-square and Fisher Exact test for categorical measures and Student's t-test for independent samples continuous parameters. For the multivariate analysis, we performed logistic regression. We used a 0.05 significance level. RESULTS A total of 468 patients were included in the study and 517 PCNL were performed. The mean age was 48.3±12.8 years, mean BMI of 27.3±5.0 and 57.8% were female. According to the ASA score, 35.1% were ASA 1, 59.5% were ASA 2 and 5.4% were ASA 3. Regarding patient position, 18% were in prone position, 66.9% in complete supine position, 4.1% in classic Valdivia and 11% in Galdakao position. Most punctures were on lower and middle calyx (65.8% and 24.8%). 9.3% of the punctures were supracostal. Mean surgical time was 114.6±52.78 min. The overall success rate was 55.1%. According to the GSS, the success rate for GSS I was 85.1%, GSS II was 59.4%, GSS III was 40.7% and for GSS IV was 23.3% (p <0.0001). On univariate analysis, the significant variables related to success were supine position (p=0.031), GSS (p<0.0001) and stone diameter (p<0.0001). After the multivariate analysis, it was found that only Guy's Stone Score was statistically significant for success. Odds ratio between GSS groups: OR12 3.55 (CI95% 1.95-6.69), OR23 1.91 (CI95% 1.19-3.08), OR34 1.92 (CI95%0.97-3.89). CONCLUSIONS The Guy's Stone Score was the only predictive factor of success for PCNL. This instrument is easy to use and should be incorporated on stone evaluation and patient counseling. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e354 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Fabio C. Vicentini More articles by this author Carlos Watanabe-Silva More articles by this author Thiago A.C. Ferreira More articles by this author Claudio B. Murta More articles by this author Joaquim F.A. Claro More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

Experiencia en nefrolitotomía percutánea con manejo ambulatorio vs hospitalización en un centro urológico, Pereira, 2009-2012

ObjectiveTo report the experience in percutaneous nephrolithotomy (PCNL), reviewing demographic and surgical variables in ambulatory and hospitalized patients. MethodsRetrospective cohort study was performed by analyzing data from 95 patients who underwent PCNL from June/2009 to May/2012. The variables included, type of stones, anesthesia, calyx puncture, residual stones, and intra -and postoperative complications. Technique: ureteral catheter and contrast medium, access to collector with 0.38-F guide, dilation with Alken, and placement of 28-F Amplatz. A 26-F rigid nephroscope and nephrostomy was used in all patients. Clinical outcome variables were evaluated in the outpatient vs hospitalization groups in the week following the procedure. Statistical analysis was performed using STATA11, P<.05. ResultsMean age was 47.09 years, and 55.79% of patients were women. A total of 58.95% of stones were at left location. Two surgeons performed the procedures, with 80% of patients in prone position, and under general anesthesia in 77.89%. The most common access was lower calyx (58.95%), and the estimated intraoperative bleeding was < 200mL in 93.68%. After the procedure, 37 patients were hospitalized and 58 were managed as outpatients. There was one case of bowel perforation, which resolved with conservative management. Postoperative pain during the week following the procedure was an average of 2 for outpatients, and 3.70 for hospitalized. Most variables were not associated with any of the initial treatment. ConclusionsPCNL is a safe technique for the management of large stones, even in patients treated on an outpatient basis with nephrostomy.© 2013 Sociedad Colombiana de Urología. Published by Elsevier España, S.L. All rights reserved.

A Cheaper Simulator for Learning Percutaneous Renal Access: A Latex Glove Model

Introduction: The most difficult step of percutaneous renal surgery is to obtain an appropriate access to the renal cavities, which reduces the risk of vascular injury and leads to a better stone-free rate.1–3 Model-based training that provides experience in percutaneous renal access may reduce the learning curve associated with the procedure and increase the safety profile for beginners as they gain experience on patients.2,3 Thus, many biological models with porcine kidney and virtual reality simulator have been developed, to facilitate the learning and training of percutaneous renal surgery.3,4–7 We present a video of a cheaper and easily available model using a latex glove for percutaneous calyx puncture. Materials and Methods: Two or three foam layers are used to simulate the abdominal wall layers. A ureteral catheter is inserted in a latex glove, which is closed using a few ligations. The glove is filled with saline solution and contrast media. It is placed on the distal half of the foams with the fingers looking toward the middle. The fingers are fixed to the foam using medical tapes. The foams are folded to cover the glove. The puncture, guidewire insertion, and small dilation are performed under fluoroscopic guidance, with the X-ray beam perpendicular to the tract. Thus, the operator's hands are outside the fluoroscopic field, similar to the technique we use in percutaneous renal access.8 Urologist and residents were taught needle access and the beginning of tract dilation. Results: The glove model is simple and quick to set up, with a preparation time of a few minutes. It is economical, by using widely available material. It can be performed in the operating room; since it is a nonbiological model, there is no risk of biologic contamination nor any hygiene or sterilization issue. Percutaneous puncture and limited dilation were possible in all the fingers and with the same techniques used in our real percutaneous access.8,9 The needle mobilization and puncture of the glove's fingertip are similar to the feeling of the calyx puncture. Beside a good fixation to the foam, the fingers have to be tightly filled to be firm to the needle puncture. Otherwise, if the finger is flaccid, the needle will push the fingertip without puncturing it. Moreover, dilation and Amplatz sheath insertion are difficult or impossible; the finger is pushed by the dilator. It is a nonbiological model, so there is a limitation in terms of tissue feeling and for anatomic relations. In addition, ultrasound-imaging guidance cannot be used. Evaluations submitted by training session participants revealed a high degree of satisfaction with model effectiveness in the application of percutaneous calyx puncture. Conclusions: This glove model seems to be an effective means of skills acquisition for percutaneous calyx puncture. Moreover, it is cheap, simple, and quick to set up, with no risks of biologic contamination. However, further technical experience and comparative studies with biologic and virtual reality simulators are necessary to evaluate this technique. No competing financial interests exist. Run time of video: 5 mins 20 secs

E106 A glove model for learning of calyx puncture in percutaneous renal surgery

The glove model is simple to set up, with a preparation time of about a few minutes. It is economical, by using widely available material. It can be performed in the operating room, since it is a non-biological model, so there is no risk of biologic contamination, nor any hygiene or sterilization issue. Percutaneous puncture and limited dilation were possible in all the fingers and with the same techniques used in our real percutaneous access [8, 9]. The needle mobilization and puncture of the glove’s fingertip are similar to the of the calyx puncture. The fingers have to be tightly filled, in order to be firm to the needle puncture. Otherwise, if the finger is flaccid the needle will push the fingertip without puncturing it. Moreover, dilation and Amplatz sheath insertion are difficult or impossible; the finger is pushed by the dilator. It is a non-biological model so there is a limitation in terms of tissue feeling and for anatomic relations. In addition, ultrasound-imaging guidance cannot be used. Evaluations submitted by training session participants revealed a high degree of satisfaction with model effectiveness in the application of percutaneous calyx puncture. Also, for learning of calyx puncture we have a model without using radiation exposure that can be used in the classroom; it is using a retroprojector with the principle of Chinese-shadows. Introduction The most difficult step of percutaneous renal surgery is to obtain an appropriate access to the renal cavities, which reduces the risk of vascular injury and leads to a better stone-free rate [1-3]. Model-based training that provides experience in percutaneous renal access may reduce the learning curve associated with the procedure and increase the safety profile for beginners as they gain experience on patients [2, 3]. Thus, many biological models with porcine kidney and virtual reality simulator have been developed, to facilitate the learning and training of percutaneous renal surgery [3, 4-7]. We present a cheaper and easily available model using a latex glove for percutaneous calyx puncture.

Supine Lithotomy versus Prone Position in Minimally Invasive Percutaneous Nephrolithotomy for Upper Urinary Tract Calculi

Objective: To compare operative time, safety and effectiveness of minimally invasive percutaneous nephrolithotomy (MPCNL) in the supine lithotomy versus prone position. Methods: Between January 2008 and December 2010, a total of 109 consecutive patients with upper urinary tract calculi were enrolled and randomly divided into group A (53 patients, supine lithotomy position) and group B (56 patients, prone position). The MPCNL procedures were performed under the guidance of real-time grayscale ultrasound system. The preoperative characteristics, intraoperative and postoperative parameters were analyzed and compared. Results: All patients were successfully operated. There was no significant difference between the two groups in stone-free rate (group A 90.1 vs. group B 87.5%, p = 0.45), mean blood loss, number of access tracts, calyx puncture, mean hospital stay (group A 6 ± 1.1 vs. group B 6 ± 1.5 days, p = 0.38) and complications. But the operative time was significantly shortened in supine lithotomy position (group A 56 ± 15 vs. group B 86 ± 23 min, p < 0.001). Conclusions: The effectiveness and safety of the supine lithotomy position for MPCNL were similar to the prone position. However, the supine lithotomy position has an important advantage of reducing the operative time. The supine lithotomy position could be a good choice to perform MPCNL.

Prone versus Modified Supine Position in Percutaneous Nephrolithotomy: a Prospective Randomized Study

Objective: To perform a prospective randomized trial comparing the efficacy and safety of percutaneous nephrolithotomy (PCNL) in the prone and modified supine positions.Methods: Between August 2010 and August 2011, 102 patients with renal calculi and 20 patients with ureteral calculi were randomized to undergo fluoroscopy and ultrasound-guided PCNL procedures in the prone or modified supine position. Baseline characteristics, puncture position, numbers of punctures, operation time, stone free rate, loss of blood, hospital stay and second phase PCNL were compared in the two groups.Results: There were no significant differences in gender, age, body mass index, stone location, stone size and the presence of hydronephrosis between the two groups. The rate of second PCNL was significantly higher and the stone clearance rate was significantly lower in the modified supine than in the prone position group. Mean operation time was significantly lower in the prone than in the modified supine position group (78 min vs 88 min, P<0.05). There were no significant differences in rates of rib and calyx puncture, numbers of punctures, mean blood loss, and mean hospital stay between the two groups.Conclusions: Both the prone and modified supine positions are effective and safe for PCNL. Operation time was longer in the modified supine group, and patients undergoing PCNL in the modified supine position more frequently required a second operation due to a lower stone clearance rate.

A different approach to the percutaneous nephrostomy by urologists

IntroductionPercutaneous nephrostomy (PCN) tube placement is generally performed in radiologic departments worldwide. However, there are a few urologist-directed studies about PCN performed with ultrasound guidance. Needle direction using a convex abdominal ultrasound probe might be difficult in unexperienced hands. In order to perform this procedure easily, we propose that a probe placed on flank or intercostal region and a long grooved needle director that never allows needle movement would be useful. We considered that a transrectal ultrasound (TRUS) probe was suitable to resolve this issue. Materials and methodFrom January 2007 to April 2011, a total of 113 percutaneous renal access (PRA) were performed using a TRUS probe in 102 patients, aged 20–84 years old. Because of the insufficient imaging capability of the TRUS probe in obese patients, with a body mass index (BMI) greater than 30kg/m2, these were excluded. Forty-two PRA were performed under local anesthesia and this group was named local anesthesia (LA) group. Seventy-one PRA were performed for nephrostomy insertion under local anesthesia supplemented by deep sedation and this cluster was named deep sedation (DS) group. ResultsTargeted calyx puncture and guide wire placement was performed in all patients (100%) but success rate of tube insertion in each group was different. Successful PCN insertion rate was 69.1% (29 of 42 cases) in LA group and 95.8% (68 of 71 cases) in DS group. No major vascular injury and/or adjacent organ injury to bowel, liver, spleen or lung was seen in any patient. ConclusionGuidance of TRUS probe, deep sedation, and modified dilators may offer a high success rate to the urologists with little experience in PCN insertion which they would find it difficult to perform.

Ultrasonography-Guided Percutaneous Nephrolithotomy for the Treatment of Urolithiasis in Patients with Scoliosis

We examined the surgical outcomes of minimally invasive percutaneous nephrolithotomy (MPCNL) in scoliotic patients with complicating urolithiasis. Two patients with scoliosis were hospitalized for MPNCL due to upper tract urolithiasis. Calyx puncture was performed in the prone position under ultrasonographic guidance. The renal access route was established using a set of 8F to 16F dilators, and a transpyelic ballistic lithotriptor was used to fragment the calculi. The stone burdens in the 2 patients were 410 mm(2) and 500 mm(2). The entire operative time was 40 to 70 minutes, and the mean time of establishing percutaneous access was 20 minutes. The calculi were completely removed by single-session pneumatic lithotripsy. The 2 patients recovered from MPCNL uneventfully, and the follow-up radiologic examinations identified no stone residual or recurrence. MPCNL is a minimally invasive modality that is effective and safe for the treatment of urolithiasis in patients with scoliosis.

Un abordaje diferente a la nefrostomía percutánea por urólogos

IntroductionPercutaneous nephrostomy (PCN) tube placement is generally performed in radiologic departments worldwide. However, there are a few urologist-directed studies about PCN performed with ultrasound guidance. Needle direction using a convex abdominal ultrasound probe might be difficult in unexperienced hands. In order to perform this procedure easily, we propose that a probe placed on flank or intercostal region and a long grooved needle director that never allows needle movement would be useful. We considered a transrectal ultrasound (TRUS) probe was suitable to resolve this issue. Material and methodFrom January 2007 to April 2011, a total of 113 percutaneous renal access (PRA) were performed using a TRUS probe in 102 patients, aged 20 to 84 years old. Because of the insufficient imaging capability of the TRUS probe in obese patients whose body mass index (BMI) greater than 30kg/m2 were excluded. Forty two PRA were performed under local anesthesia and this group was named local anesthesia (LA) group. Seventy one PRA were performed for nephrostomy insertion under local anesthesia supplemented by deep sedation and this cluster was named deep sedation (DS) group. ResultsTargeted calyx puncture and guide wire placement was performed in all patients (100%) but success rate of tube insertion in each group was different. Successful PCN insertion rate was 69.1% (29 of 42 cases) in LA group and 95.8% (68 of 71 cases) in DS group. No major vascular injury and/or adjacent organ injury to bowel, liver, spleen or lung was seen in any patient. ConclusionGuidance of TRUS probe, deep sedation, and modified dilators may offer a high success rate to the urologists with little experience in PCN insertion which they would find it difficult to perform.

Use of a Virtual Reality Simulator to Improve Percutaneous Renal Access Skills: A Prospective Study in Urology Trainees

Objectives: This study aims to assess the impact of a virtual reality trainer in improving percutaneous renal access skills of urological trainees. Methods: A total of 36 urology trainees participated in this prospective study. Initially, they were taken through the exercise of gaining access to the lower pole calyceal system and introducing a guidewire down the ureter. Trainees’ performance was then assessed by virtual reality-derived parameters of the simulator at baseline and after 2 h of training. Results: Participants who underwent training with the simulator demonstrated significant improvement in several parameters compared to their baseline performance. There was a statistically significant correlation between total time to perform the procedure and time of radiation exposure, radiation dose and correct calyx puncture (p < 0.01). Trainees needed a mean of 15.8 min from skin puncture to correct guidewire placement into the pelvicalyceal system before and 6.49 min following training. Conclusions: We found percutaneous renal access skills of trainees improve significantly on a number of parameters as a result of training on the PERC Mentor TM VR simulator. Such simulated training has the potential to decrease the risks and complications associated with the early stages of the learning curve when training for percutaneous renal access in patients.