Shashikant Mishra

Scarless single port transumbilical nephrectomy and pyeloplasty: first clinical report

Associate Editor

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.

Treating renal calculi 1–2 cm in diameter with minipercutaneous or retrograde intrarenal surgery: a prospective comparative study

Study Type – Therapy (pattern of practice survey)

'Microperc' micro percutaneous nephrolithotomy: evidence to practice.

Purpose of review Miniaturization of instruments in percutaneous nephrolithotomy (PCNL) has spawned an interest in so-called ‘microperc’ in which the procedure is carried out through 16-gauge needle. Recent findings The greatest limitation of extracorporeal shock wave lithotripsy is its unpredictable results. The main limitation of retrograde intrarenal surgery is high sustainable cost and poor durability. The main limitation of PCNL is its invasiveness and associated morbidity. The interest in reducing the tract size was to potentially reduce the invasiveness of the procedure, and, therefore, attending complications. In a historical study, postrenal biopsy bleeding was found to be significant only after the tract of the needle was less than 16 gauge. Microperc extended the concept of ‘All-seeing needle’ to perform PCNL through a 4.85-Fr (16 gauge) tract. The working hypothesis of the ‘All-seeing needle’ is that if the initial tract is perfect, then the tract-related morbidity could be reduced. The optical needle helps to avoid any traversing viscera and confirms the visual cues of a correct papilla. The other advantage of microperc is that it is a novel single-step renal access procedure, resulting in a shorter insertion to lithotripsy time. This may provide a new standard of obtaining renal access. Summary Only a few published studies have documented efficacy and safety. Till further prospective and multicentric articles are published, it is still an experimental procedure requiring further research.

Questioning the wisdom of tubeless percutaneous nephrolithotomy (PCNL): a prospective randomized controlled study of early tube removal vs tubeless PCNL

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

Validation of Virtual Reality Simulation for Percutaneous Renal Access Training

OBJECTIVE The objective of this study was to assess the face, content, construct, convergent, and predictive validities of virtual reality-based simulator in acquisition of skills for percutaneous renal access. MATERIALS AND METHODS A cohort of 24 participants comprising novices (n = 15) and experts (n = 9) performed a specific task of percutaneous renal puncture using the same case scenario on PERC Mentor. All objective parameters were stored and analyzed to establish construct validity. Face and content validities were assessed by having all experts fill a standardized questionnaire. All novices underwent further repetition of the same task six times. The first three were unsupervised (pretest) and the later three after the PERC Mentor training (posttest) to establish convergent validity. A subset of five novice cohorts performed percutaneous renal access in an anesthetized pig before and after the training on PERC Mentor to assess the predictive validity. Statistical analysis was done using Students t-test (p <or= 0.05 statistically significant). RESULTS The overall useful appraisal was 4 in a scale of 1 to 5 (1 is poor and 5 is excellent). Experts were significantly faster in total performance time 187 +/- 26 versus 222 +/- 29.6 seconds (p < 0.005) and required fewer attempts to access 2.00 +/- 0.20 versus 2.8 +/- 0.4 (p < 0.001), respectively. The posttest values for the trained novice group showed marked improvement with respect to pretest values in total performance time 42.7 +/- 6.8 versus 222 +/- 29.6 seconds (p < 0.001), fluoroscopy time 66.9 +/- 10.20 versus 123.3 +/- 19.40 seconds (p < 0.0001), decreasing number of perforation 0.8 +/- 0.3 versus 1.3 +/- 0.2 (p < 0.001), and number of attempts to access 1.3 +/- 0.10 versus 2.00 +/- 0.20 (p < 0.001), respectively. Access without complication was attained by all five when compared with one with three complications (baseline vs. posttraining group, respectively) in the porcine model. CONCLUSION All aspects of validity were demonstrated on virtual reality-based simulator for percutaneous renal access.

Predicting effectiveness of extracorporeal shockwave lithotripsy by stone attenuation value.

PURPOSE The aim of this study was to evaluate the effect of stone attenuation value on the effectiveness of extracorporeal shockwave lithotripsy (SWL) for upper urinary tract stones. METHODS In this prospective study, 99 patients underwent SWL for solitary renal and upper ureteral stones from January 2007 to March 2009. All patients underwent CT scan before SWL. The mean attenuation value of stones in our study was 1213.3 +/- 314.5 Hounsfield units (HU). Group A consisted of 42 patients with stones of attenuation value <1200 HU and group B had 57 patients with stones of attenuation value >1200 HU. Stone size, location, requirement of number of shockwaves, shock intensities (power), retreatment rate, complication rate, auxiliary procedure rate, and effectiveness quotient (EQ) ratio were studied. RESULTS The mean total number of shocks required to fragment the stones in groups A and B were 1317.1 +/- 345.3 and 1646.5 +/- 610.8, respectively (p = 0.001), with a mean shock intensity of 12.2 +/- 0.7 and 12.4 +/- 0.5 kV, respectively (p = 0.03). Retreatment was not required in patients of group A, but 14.03% patients in group B required retreatment (p < 0.0001). Clearance rate in group A was 88.1%, whereas in group B it was 82.5% (p = 0.35). Auxiliary procedure rates were 9.5% and 10.5% in groups A and B (p = 0.22), respectively. EQ was 80.4% and 66.2% in groups A and B (p = 0.03), respectively. Complication rates were similar with 2.4% and 3.5% in groups A and B, respectively (p = 0.37). Significant correlation was recorded for total number and intensity of shocks with stone attenuation value. CONCLUSIONS The EQ of SWL for upper urinary tract stones was significantly better for stones with lower attenuation value. The number and intensity of shocks required to fragment these stones with lower attenuation value were also significantly lower.

Percutaneous renal access training: content validation comparison between a live porcine and a virtual reality (VR) simulation model

Study Type – Operational research (education) content analysis
Level of Evidence 3b

The Impact of Percutaneous Nephrolithotomy in Patients with Chronic Kidney Disease

INTRODUCTION The impact of percutaneous nephrolithotomy (PCNL) in chronic kidney disease (CKD) patients was retrospectively analyzed in this study. We analyzed the factors that can impair renal function and predict the need for renal replacement therapy (RRT) after PCNL. PATIENTS AND METHODS Ninety-one chronic kidney patients with a mean age of 52.5 +/- 13 involving 117 renal units underwent PCNL in our institution for 5 years. A mean of 1.6 +/- 1.1 tracks and 1.3 +/- 0.6 sittings per renal unit was required for PCNL. The estimated glomerular filtration rate (eGFR) pre-PCNL (postdrainage), peak eGFR on follow-up, and eGFR at last follow-up were recorded. The CKD stage pre-PCNL was compared with the CKD stage at last follow-up. RESULTS Complete clearance, auxiliary procedure, and complication rates were 83.7%, 2.5%, and 17.1%, respectively. The mean eGFR pre-PCNL and peak eGFR at follow-up were 32.1 +/- 12.8 and 43.3 +/- 18.8 mL/minute/1.73 m(2), respectively (p < 0.0001). At a mean follow-up of 329 +/- 540 days, deterioration with up-migration of CKD stage was seen in 12 patients (13.2%). Eight patients (8.8%) required RRT in the form of either maintenance hemodialysis or renal transplantation. Postoperative bleeding complication requiring blood transfusions was seen in seven (5.9%) and two (1.7%) of the renal units subsequently required super selective angioembolization. There were two mortalities in the postoperative period. Postoperative complications and peak eGFR (less than 30 mL/minute/1.73 m(2)) at follow-up are two factors that predict renal deterioration and RRT. Renal parenchymal thickness (<8 mm) also predicts the need for RRT. CONCLUSION PCNL has a favorable impact in CKD patients with good clearance rates and good renal functional outcome. PCNL in this high-risk CKD population is to be done with care and full understanding of its complications.

Training in percutaneous nephrolithotomy.

Purpose of review Training in percutaneous nephrolithotomy (PCNL) necessitates the trainee to climb the steep learning curve of this procedure sequentially. The initial steps of the process should be the acquisition of the necessary skills in a nonintimidating skills lab. We review the current scenario of the training in PCNL and advocate the means that may improve the overall patient care. Recent findings The training involves a comprehensive development of the trainee. Initial process starts with the cognitive skills update through conferences and observing peers do the procedure. Rapid prototyping could be useful for resident education. The benefits of three-dimensional stereolithographic biomodeling produced from computed tomography data may aid in achieving optimal access. Skills lab involving wet and dry lab reinforce the cognitive skills. The advantage of live anesthetized porcine model is it being a more realistic model and assessment tool. The specific advantage of the dry lab simulator is of repetitive tasking and easier setup feasibility. There is a lack of guideline for the lab setup and training. Funding, location, number of models installed, curriculum, a trained mentor, and instructor are the critical components that need to be planned in advance. Summary Training in PCNL starts with cognitive knowledge, reinforcement through repetitive nonpatient basic skills acquisition in wet and dry skills lab, prototyping the technique before the actual procedure, and finally supervised training under an able mentor.