Ravindra Sabnis

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.

The Dretler stone cone: A device to prevent ureteral stone migration: The initial clinical experience

PURPOSE Retrograde stone migration during ureteroscopic lithotripsy occurs in 5% to 40% of proximal and distal ureteral stone cases. This migration increases morbidity and the need for auxiliary procedures. The Dretler stone cone (Medsource, Norwell, Massachusetts) is a novel device to prevent proximal stone migration and facilitate fragment extraction during ureteroscopic lithotripsy. We assessed the safety and efficacy of the Dretler stone cone in the clinical setting and compared it prospectively with a conventional flat wire basket during ureteroscopy for ureteral calculi. MATERIALS AND METHODS To our knowledge we report the initial clinical use of the Dretler stone cone in 50 consecutive patients with ureteral calculi undergoing ureteroscopic extraction. Calculi were situated above the sacroiliac joint in 24 cases, over the sacroiliac joint in 15 and below the sacroiliac joint in 11. Pneumatic lithotripsy was done in 42 cases. In the remaining 8 cases ureteroscopic (3) or fluoroscopic (5) intact stone extraction was performed. The later 23 cases using the Dretler stone cone were prospectively compared with 20 of ureteroscopic intracorporeal lithotripsy using a standard flat wire basket. RESULTS The Dretler stone cone was successfully placed in all 50 cases. In 41 patients it was placed via cystoscopy under fluoroscopic guidance, while 9 impacted stones required ureteroscopic placement. Six patients in whom the Dretler stone cone was used had residual fragments less than 3 mm. No patient required auxiliary procedures. In the prospective trial no patients in Dretler stone cone group had residual fragments greater than 3 mm. or required auxiliary procedures. However, in the flat wire basket group residual stones greater than 3 mm. were present in 6 cases (30%, p <0.001), while auxiliary procedures were required in 4 (20%, p <0.01). CONCLUSIONS The Dretler stone cone represents a new generation of basketry that minimizes proximal ureteral stone migration and allows safe extraction of fragments during ureteroscopic lithotripsy. In our experience it is associated with a lower incidence of significant residual fragments and fewer auxiliary procedures than conventional flat wire baskets.

Micropercutaneous nephrolithotomy (microperc) vs retrograde intrarenal surgery for the management of small renal calculi: a randomized controlled trial

To compare micropercutaneous nephrolithotomy (microperc) and retrograde intrarenal surgery (RIRS) for the management of renal calculi <1.5 cm with regard to stone clearance rates and surgical characteristics, complications and postoperative recovery.

Fluid Absorption During Percutaneous Nephrolithotomy: Does It Matter?

BACKGROUND AND PURPOSE Large amounts of irrigating fluid are used during percutaneous nephrolithotomy (PCNL). This use may be associated with migrating calculus debris, infection, and fluid absorption. This study evaluated the presence of fluid absorption during PCNL, its clinical and biochemical significance, and maneuvers to reduce it. PATIENTS AND METHODS Fluid absorption during PCNL was evaluated in 148 patients by estimating the expired breath ethanol concentration. Factors thought to affect the amount of fluid absorbed were studied, including the amount of irrigating fluid used, the number of nephrostomy tracts, the presence of a low-pressure system, the presence of existing tracts, and complications such as bleeding or perforation of the pelvicaliceal wall. RESULTS Fluid absorption was evident in all patients, although no patient had any clinical or biochemical evidence of intraoperative or postoperative electrolyte imbalance. Creating a low-pressure system by using an Amplatz sheath, reducing the amount of irrigating fluid used, and staging the procedure significantly reduced the amount of fluid absorbed. CONCLUSIONS Fluid absorption does take place during PCNL. This may be clinically significant in patients with compromised cardiorespiratory or renal status and in pediatric patients, leading to fluid overload. Using a low-pressure system, reducing the nephroscopy time and the amount of irrigating fluid used, and staging the procedure for large renal stone burdens, especially in the presence of complications such as perforation of the pelvicaliceal system, reduces fluid absorption and avoids volume overload. Fluid absorption may also be associated with both infective and noninfective pyrexia, necessitating adequate preoperative control of urinary infection.

Laparoendoscopic single-site donor nephrectomy: a single-center experience.

OBJECTIVES To present our experience with 13 patients undergoing laparoendoscopic single-site live donor nephrectomy. METHODS The Quadport/Triport (Advanced Surgical Concepts, Ireland) was inserted through an incision in the umbilicus. Apart from standard laparoscopic instruments, we used extra-long harmonic scalpel, suction, and bent instruments, particularly for upper pole dissection. After securing the hilum, the graft was brought near the umbilical extraction site with a grasper inserted through an extra 3- or 5-mm port and easily retrieved with the help of 2 fingers. The parameters analyzed were warm ischemia time, operative time, blood loss, postoperative visual analogue score, grafts retrieval time, and artery, vein, and ureteral length. RESULTS Mean body mass index was 22.18 +/- 3.42 kg/m(2) (range 17.9-29.78). The mean operative time, blood loss, warm ischemia time, and hospital stay were 176.9 +/- 42.47 minutes, 158 +/- 78 mL, 6.79 +/- 1.7 minutes, and 3 +/- 0.45 days (range 2-5), respectively. Graft artery, vein, and ureteral length was 3.8 +/- 0.4, 4 +/- 0.12, and 14.5 cm (range 13-16), respectively. The urine output was prompt in all cases. Visual analogue score in the donor at 2 weeks was 0/10 in all cases. Eleven patients required extra 3- or 5-mm port. Cosmesis was excellent, with the mean incision length of 5.23 +/- 0.96 cm. CONCLUSIONS The laparoendoscopic single-site donor nephrectomy in our initial experience is efficacious and a feasible, minimally invasive option for donors in renal transplantation. Further prospective studies with conventional laparoscopic donor nephrectomy are required to establish its current status.

Developments in technique and technology: the effect on the results of percutaneous nephrolithotomy for staghorn calculi

To review the development of the technique of percutaneous nephrolithotomy (PCNL), for ease of learning and development of instrumentation for staghorn calculi at our centre since 1991, and to assess the results and outcomes.

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)

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.