Percutaneous Nephrolithotomy in the Superobese: A Comparison of Outcomes Based on Body Mass Index

Introduction: Percutaneous nephrolithotomy (PCNL) is considered the gold standard for treatment of large renal calculi. Although several investigators have examined the feasibility and outcomes associated with PCNL in obese patients, these studies have been limited by small sample size, lack of a comparator group, or few patients at body mass index (BMI) extremes. We thus compared outcomes of superobese (BMI >50) patients undergoing PCNL vs both an “overweight” and “ideal” cohort. Methods: We used a prospectively maintained database to identify ideal (BMI 18.5–25), overweight (BMI 25.1–49.9), and superobese (BMI ≥50) patients who underwent PCNL. Our primary objective was to compare surgical outcomes between groups measured by the percent of patients who required secondary PCNL. We then compared complication rates, need for transfusion, and length of stay (LOS) using chi-square testing and ANOVA where appropriate. Results: A total of 1152 patients were identified of which 254 were classified as ideal, 840 as overweight, and 58 as superobese. The overweight cohort had a higher mean age and greater proportion of males, whereas staghorn stones were more common in the superobese group. Comorbid conditions were more commonly observed in the superobese cohort. Otherwise, the groups were similar. Surgical outcomes were comparable with 47.2%, 42.0%, and 38.0% of ideal, overweight, and superobese patients requiring secondary PCNL (p = 0.25) with no difference in complication rates, need for transfusion, or LOS. Conclusion: PCNL can be effectively and safely performed in superobese patients with no difference in surgical outcomes or complications when compared to ideal or overweight patient cohorts

A Usability Comparison of Laser Suction Handpieces for Percutaneous Nephrolithotomy

Introduction: The holmium laser has revolutionized the practice of minimally invasive endoscopy for kidney stones. Recently, a novel, rigid handpiece for use in percutaneous nephrolithotomy (PCNL) that couples the holmium laser with suction has been developed. To date, limited data exist regarding the usability and ergonomics of such treatment systems. We thus sought to compare surgeon-rated usability with three different suction laser handpieces in a porcine model. Materials and Methods: We performed bilateral reverse PCNL on four female domestic farm pigs. After induction of general anesthesia, percutaneous access was obtained into each kidney by using biplanar fluoroscopy and 8?mm stones (plaster of Paris) were inserted into the calix or renal pelvis for treatment. Four surgeons tested the LASER Suction Tube (Karl Storz?, Germany), LithAssist? (Cook? Medical), and Suction Handpiece (HP) (Lumenis?, Israel) by using a combination of fragmentation (5 Joules/20 Hertz) and dusting (0.8 Joules/80 Hertz) settings on the Lumenis pulse 120 H laser. The primary outcome assessed was the ease of use of the three devices as measured by a surgeon questionnaire. Results: A total of 15 stones were treated in 8 renal units. The mean time required for stone fragmentation was 8?min. The mean handling and suction efficiency scores were similar between devices. The Suction HP offered the best laser fiber visibility during lithotripsy. Conclusion: Suction laser handpieces offer an option to treat renal stones via PCNL, with limited differences noted in most surgeon ratings between devices.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140086/1/end.2016.0203.pd

Getting Out of a PCCL: Percutaneous Cholecystolithotomy as a Salvage Treatment Option for Gallstone Removal in Patients Deemed Unfit for Standard Surgical Approaches

Definitive management of acute cholecystitis or symptomatic cholelithiasis in exceedingly high-risk patients remains a clinical dilemma. In certain cases, treatment through a percutaneous approach following standard techniques and principles similar to those of percutaneous nephrolithotomy may be considered. However, one potential challenge, particularly among a high-risk population, is the possible necessity to stay on obligate anticoagulation for pre-existing medical reasons. To date, there have been no prior reports documenting the role of this procedure in patients on systemic anticoagulation, particularly clopidogrel. Here we report a case of a percutaneous cholecystolithotomy performed on an elderly patient unable to stop dual antiplatelet therapy (aspirin and clopidogrel) secondary to recent drug eluting stent placement for myocardial infarction

Comprehensive Costs Associated with Fiberoptic and Digital Flexible Ureteroscopes at a High Volume Teaching Hospital

Introduction Modern flexible ureteroscope ownership costs are considerable. Most prior estimates focus exclusively on repair costs, likely underestimating overall costs, including those of acquisition and reprocessing. Furthermore, to our knowledge no prior cost analyses focus on the latest generation digital flexible ureteroscope, which may differ due to unique purchase and repair prices. We sought to gain greater insight into the comprehensive costs associated with modern flexible ureteroscope use, particularly the difference between digital and fiberoptic models. Methods Data on use and repair of fiberoptic Storz Flex-X2 and digital Flex-Xc flexible ureteroscopes from 2011 to 2015 were reviewed. List prices and repair costs were obtained from Storz. Per case reprocessing costs were estimated, accounting for disposables, reagents and labor. Maintenance costs were estimated by combining cost of repairs and reprocessing. Analyses were performed at list pricing and standard discount rates. Global flexible ureteroscope costs were calculated to account for the cost of acquisition, repair and maintenance of a new scope during its first 100 uses. Results Global costs associated with digital flexible ureteroscope ownership were 1.3 to 1.4 times greater than fiberoptic on a per case basis ($1,008/$1,086 vs $715/$835). The majority of expenses went toward scope repairs (73% vs 71%), with instrument purchase (23% vs 24%) and reprocessing (4% vs 5%) being less costly. Repair rates were not significantly different between fiberoptic and digital devices (12.5 vs 11.5, p=0.757). Conclusions Expenditures associated with ownership of modern flexible ureteroscopes are considerable and driven primarily by the high cost of repairs. Digital instruments are more costly despite comparable rates of flexible ureteroscope damage

Accuracy of Daily Fluid Intake Measurements Using a "Smart" Water Bottle

High fluid intake is an effective preventative strategy against recurrent kidney stones but is known to be challenging to achieve. Recently, a smart water bottle (Hidrate Spark™, Minneapolis, MN) was developed as a non-invasive fluid intake monitoring system. This device could help patients who form stones from low urine volume achieve sustainable improvements in hydration, but has yet to be validated in a clinical setting. Hidrate Spark™ uses capacitive touch sensing via an internal sensor. It calculates volume measurements by detecting changes in water level and sends data wirelessly to users’ smartphones through an application. A pilot study was conducted to assess accuracy of measured fluid intake over 24 h periods when used in a real life setting. Subjects were provided smart bottles and given short tutorials on their use. Accuracy was determined by comparing 24-h fluid intake measurements calculated through the smart bottle via sensor to standard volume measurements calculated by the patient from hand over the same 24 h period. Eight subjects performed sixty-two 24-h measurements (range 4–14). Mean hand measurement was 57.2 oz/1692 mL (21–96 oz/621–2839 mL). Corresponding mean smart bottle measurement underestimated true fluid intake by 0.5 ozs. (95% CI −1.9, 0.9). Percent difference between hand and smart bottle measurements was 0.0% (95% CI − 3%, 3%). Intraclass correlation coefficient (ICC), calculated to assess consistency between hand measures and bottle measures, was 0.97 (0.95, 0.98) indicating an extremely high consistency between measures. 24-h fluid intake measurements from a novel fluid monitoring system (Hidrate Spark™) are accurate to within 3%. Such technology may be useful as a behavioral aide and/or research tool particularly among recurrent stone formers with low urinary volume

Transgluteal CT-Guided Percutaneous Renal Access for Percutaneous Nephrolithotomy in a Pelvic Horseshoe Kidney

CT-guided percutaneous renal access has been described as a safe and effective access technique in patients with complex anatomy, including ectopic kidney, retrorenal colon, spinal dysraphism, hepatomegaly, and splenomegaly. In comparison to conventional intraoperative fluoroscopic-guided access, CT imaging allows for delineation of surrounding structures that are at risk for injury during percutaneous access. However, previous reports indicate that pelvic kidneys might be inaccessible percutaneously without laparoscopic assistance. Herein, we present a novel transgluteal route to renal access for percutaneous nephrolithotomy (PCNL) in a patient with a pelvic horseshoe kidney and severe spinal deformity

Integration and utilization of modern technologies in nephrolithiasis research

Nephrolithiasis, or stones, is one of the oldest urological diseases, with descriptions and treatment strategies dating back to ancient times. Despite the enormous number of patients affected by stones, a surprising lack of conceptual understanding of many aspects of this disease still exists. This lack of understanding includes mechanisms of stone formation and retention, the clinical relevance of different stone compositions and that of formation patterns and associated pathological features to the overall course of the condition. Fortunately, a number of new tools are available to assist in answering such questions. New renal endoscopes enable kidney visualization in much higher definition than was previously possible, while micro-CT imaging is the optimal technique for assessment of stone microstructure and mineral composition in a nondestructive fashion. Together, these tools have the potential to provide novel insights into the aetiology of stone formation that might unlock new prevention and treatment strategies, and enable more effective management of patients with nephrolithiasis

Electromagnetic Guided Percutaneous Renal Access Outcomes Among Surgeons and Trainees of Different Experience Levels: A Pilot Study

Objective To determine feasibility of an electromagnetic (EM) guidance system (Auris Health, Redwood City, CA) in obtaining percutaneous renal access among urologists and trainees of different experience levels. EM-guidance is appealing for access as it allows real time, 3-dimensional targeting without radiation. Few studies have explored this for percutaneous nephrolithotomy (PCNL) and none have assessed its potential to decrease the learning curve in obtaining access using traditional techniques. Methods Institutional Animal Care and Use Committee approval was obtained to compare EM-guided percutaneous access to fluoroscopic guided access in a porcine model. Voluntary participants included urology trainees and faculty. They were categorized as beginner (no prior primary percutaneous nephrolithotomyexperience), intermediate (10-100 prior) and advanced (>100). Each participant attempted an EM and fluoroscopic guided puncture. Primary outcome was successful puncture. Secondary outcomes included access time, fluoroscopy time, and number of attempts. Participants were limited to 3 attempts and 10 minutes total to obtain access using each technique. Results Fourteen participants (6 beginners, 4 intermediates, and 4 experts) attempted 28 punctures. Overall success using EM-guidance was 93% compared to 71% using fluoroscopy ( P = .33). EM punctures had shorter access times (85 vs 255 seconds, P <.01) required fewer attempts (1 vs 2, P = .04) and had decreased associated fluoroscopy times (1 vs 96 seconds, P <.01) excluding the initial retrograde pyelogram and guidance of the ureteroscope to the desired calyx. Beginners showed comparable success rates and outcomes relative to experts despite higher access times. Conclusion EM-guidance is a promising new technique to decrease the learning curve of percutaneous access with high success rates and minimal radiation

Association Between Randall's Plaque Stone Anchors and Renal Papillary Pits

Introduction: Renal papillary pits are commonly encountered during ureteroscopy. The mechanism by which such pits arise is unclear. One hypothesis is that pits represent sites where stones overgrowing Randall's plaque (RP) were dislodged. We sought to examine this theory by using digital ureteroscopy and stone μCT. Materials and Methods: Patients undergoing endoscopic stone removal had procedures recorded and stones analyzed by using μCT. Stones with evidence of Randall's plaque anchors (RPAs) were identified in a blinded fashion. Surgical videos were reviewed independently by two urologists. Results: Twenty-eight patients had μCT-confirmed stones with RPA. Among them, 93% were recurrent stone formers and 75% had had prior stone procedures. Metabolic abnormalities were present in 87%, with 79% classified as idiopathic calcium oxalate stone formers. A mean of 7.6 stones with RPA were identified per procedure. In each case, papillary pits were visualized before any stone manipulation and in several cases the active dislodgement of an attached stone led to immediate identification of an underlying pit. Such stones routinely demonstrated an RPA on μCT. The average depth of RPA was 302 ± 172 μm, consistent with the corresponding shallow pits visualized on the papillary surface. Conclusions: Stones overgrowing RP are capable of pulling away a piece of papilla when dislodged, resulting in a visible papillary pit. This process manifests as an RPA on the undersurface of the stone and a papillary pit on the corresponding area of attachment. Identification of pits may help identify patients who form stones primarily by the RP mechanism

Contemporary Practice Patterns of Flexible Ureteroscopy for Treating Renal Stones: Results of a Worldwide Survey

Introduction: Flexible ureteroscopy (fURS) is increasingly used in the treatment of renal stones. However, wide variations exist in technique, use, and indications. To better inform our knowledge about the contemporary state of fURS for treating renal stones, we conducted a survey of endourologists worldwide. Methods: An anonymous online questionnaire assessing fURS treatment of renal stones, consisting of 36 items, was sent to members of the Endourology Society in October 2014. Responses were collected through the SurveyMonkey system over a 3-month period. Results: Questionnaires were answered by 414 surgeons from 44 countries (response rate 20.7%). U.S. surgeons accounted for 34.4% of all respondents. fURS was routinely performed in 80.0% of institutions, with 40.0% of surgeons performing >100 cases/year. Respondents considered fURS to be first-line therapy for patients with renal stones 2?cm. Basket displacement for lower pole stones was routinely performed by 55.8%. Ureteral access sheaths (UAS) were preferred for every case by 58.3%. Respondents frequently utilized high-power lasers and dusting techniques. Criteria for determining stone-free rate were defined as zero fragments or residual fragment (RF) <1, <2, <3, and <4?mm by 30.9%, 8.9%, 31.5%, 15.8%, and 11.2% of respondents, respectively. Conclusion: The overwhelming majority of endourologists surveyed consider fURS as a first-line treatment modality for renal stones, especially those <2?cm. Use of UAS, high-power holmium lasers, and dusting technique has become popular among practitioners. When defining stone free after fURS, the majority of endourologists used a zero fragment or RF <2?mm definition.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140082/1/end.2015.0260.pd