Ambulatory Percutaneous Nephrolithotomy in a Free-Standing Surgery Center: An Analysis of 500 Consecutive Cases.

Introduction: Percutaneous nephrolithotomy (PCNL) is an effective procedure for removal of large kidney stones; however, PCNL has traditionally been reserved for inpatient surgery. Certain cases are being performed entirely at an ambulatory surgery center (ASC), known as ambulatory PCNL (aPCNL). Materials and Methods: Five hundred consecutive PCNL procedures performed at a free-standing ASC between April 2015 and February 2019 were analyzed. Patient demographics, stone characteristics, operative characteristics, and postoperative data, including transfer to hospitals, 30-day readmissions, and complications > Clavien I, were recorded. Results: The mean age of patients undergoing PCNL at the ASC was 57 (range: 16-86) and body mass index 30 (16-49). American Society of Anesthesiologists (ASA) compositions are as follows: ASA 1 (6.5%), ASA 2 (56.2%), ASA 3 (37.2%), and ASA 4 (0. 1%). The mean stone burden was 30 mm (5-140). Standard tract dilation (24-30F) comprised 77% of cases. Ninety-two percent of cases were performed with a single tract, and 99% of cases had a ureteral stent as the only form of drainage (tubeless PCNL). The mean operative time was 104 minutes (32-305), and postanesthesia care unit time was 97 minutes (37-247). The predicted stone-free rate was 84%. Twelve patients (2.4%) required transfer to hospital, and the 30-day readmission rate was 4.2%. Conclusion: aPCNL is a safe and feasible procedure if performed by a high volume endourologist, even within the confines of a free-standing ASC. It is our opinion that the utilization of endoscopic combined intrarenal surgery facilitates high stone-free rates with minimal morbidity and low readmission rates. The institutional review board number is WIRB # 20171472.

Cost effectiveness and robot-assisted urologic surgery: does it make dollars and sense?

INTRODUCTION: The introduction of the robotic surgical platform has led to distinct changes in practice patterns and the utilization of minimally invasive surgery in urology. While use of the robotic system is associated with improvements in perioperative outcomes such as estimated blood loss and hospital stay, there are significant fixed and variable costs with the purchase, maintenance and use of the robotics system that has led many authors to investigate the cost effectiveness of robotic urologic surgery. We sought to examine the best current available evidence for the cost effectiveness of robotic urologic surgery. EVIDENCE ACQUISITION: Comprehensive electronic literature searches were conducted without language restriction to identify reports of published studies within PubMed/Medline, SCOPUS and Web of Science. Relevant articles were examined and reference lists cross referenced to find additional pertinent publications. EVIDENCE SYNTHESIS: PubMed literature searches of "robot urology cost" (304 articles) "robotic prostatectomy cost" (215 articles), "robotic nephrectomy cost" (87 articles), "robotic cystectomy cost" (44 articles) and "robotic pyeloplasty cost" (41 articles) were initially reviewed in abstract form to find appropriate articles for inclusion. Given that robotic cystectomy (559 articles), robotic pyeloplasty (344 articles) robotic retroperitoneal lymph node dissection (59 articles) are less frequently performed than robotic prostatectomy, all available articles published from January 1st 2000 until July 31st 2016 were reviewed for potential inclusion. After excluding duplicates, appropriate articles were pulled for full text review. 49 articles were used for the final analysis. CONCLUSIONS: The available literature on the cost effectiveness of robotic urologic surgery is somewhat limited by heterogeneity of research methods, local cost variations and methods for determining costs associated with surgical outcomes. The introduction of the robotic surgical platform has led to a dramatic change in the availability and utilization of laparoscopic surgery and is associated with both favorable perioperative outcomes as well as significantly greater fixed costs related to instrumentation and equipment expenses. Well-designed trials comparing open and robotic approaches in the contemporary era of widespread robotic adoption with quality of life and validated economic metrics will be necessary to provide evidence for continued use of this valuable technology.

Stability and Spine Pedicle Screws Fixation Strength-A Comparative Study of Bone Density and Insertion Angle.

STUDY DESIGN: Analysis of insertion angle and bone density on the pedicle screw fixation strength with a novel testing protocol that accounts for the articular processes. OBJECTIVE: To analyze the relationship between pedicle screw fixation strength and bone mineral density for different transverse screw insertion angles. SUMMARY OF BACKGROUND DATA: The stability of the screw can become compromised by demineralization of the vertebral bone due to diseases such as osteoporosis. A weakening of the bone-screw interface, and therefore, a decrease in the fixation strength of the screw, leads to an increased probability of instrument failure, most commonly by screw loosening or screw pullout. METHODS: Using the ASTM F543 as reference, we performed pullout tests with an Instron mechanical testing machine of a posterior fixation construct mimicking two pedicle screws connected at a distance of 40 mm as suggested by the ASTM F1717 on four densities of polyurethane foam in accordance with the ASTM F1839-08 standard to simulate bone densities ranging from osteoporotic (5 pcf) to higher than normal (20 pcf) in four transverse insertion angles. RESULTS: A linear regression with two independent variables was found to be Y = -354.8812 + 91.8102 × X1 - 6.8747 × X2 (X1 = density [pcf], X2 = angle [degrees]), with a correlation coefficient of 0.95 for all the experimental data. CONCLUSIONS: Pedicle screw insertion angle and bone density are critical to pullout strength. However, in osteoporotic bone, the insertion angle has only a marginal influence on pullout strength. LEVEL OF EVIDENCE: V.