Initial Clinical Experience With a Novel Robotically Assisted Platform for Combined Mini-Percutaneous Nephrolithotomy and Flexible Ureteroscopic Lithotripsy.

PURPOSE: We sought to evaluate the technical feasibility of performing a combined robotically assisted mini-percutaneous nephrolithotomy (PCNL) and flexible ureteroscopy (URS) procedure by a single urologist using the MONARCH Platform, Urology (Johnson & Johnson MedTech, Redwood City, California). MATERIAL AND METHODS: In this prospective, first-in-human clinical trial, 13 patients underwent robotically-assisted PCNL for renal calculi at the University of California-Irvine, Department of Urology. Successful completion of the procedure was assessed as the primary endpoint. Postoperative adverse events were monitored for 30 days following the completion of the procedure. Stone ablation efficiency was evaluated on postoperative day 30 with low-dose 2-3 mm slice CT scans. Patients were classified according to the maximum length of their residual stone fragments as either absolute stone-free (Grade A), < 2 mm remnants (Grade B), or 2.1-4.0 mm remnants (Grade C). RESULTS: The combined robotic mini-PCNL and URS procedure was successfully completed in 12 of 13 procedures. No robotic device-related adverse events occurred. Preoperative stone burden was quantified by both maximum linear measurement (median 32.8 mm) as well as by CT-based volume (median 1645.9 mm3). Using the unique robotically assisted targeting system, percutaneous access was gained directly through the center of the renal papilla in a single pass in all cases. Median operative time was 187 minutes (range: 83-383 minutes). On postoperative day 30, a 98.7% (range: 72.9%-100.0%) volume reduction was achieved, with 5 Grade A (38.5%), 1 Grade B (7.7%), and 2 Grade C (15.4%). Three patients experienced complications (2 grade 1 and one grade 2 Clavien-Dindo). CONCLUSIONS: Our preliminary investigation demonstrates the safety, efficacy, and feasibility of a unique robotic-assisted combined mini-PCNL and URS platform.

The Viscoelastic Behavior of Soft Tissues Must be Accounted for in Stapler Design and Surgeon Technique.

BACKGROUND: Since its adoption as a surgical technique over a half-century ago, stapling has continually undergone improvements, both in the devices used and in our understanding of tissue mechanics. To best design and use stapling devices, it is beneficial to have an intimate knowledge of the response of tissue to compression and stapling dynamics. This paper provides the relevant background in the field of biomechanics, and in particular addresses the viscoelastic behavior of soft tissues under compression. Biomechanics of Stapling: The change in shape of a solid, or strain, is related to the load applied, or stress. Biological tissues are known to have non-linear relationships between stress and strain, and generally the relationships are anisotropic (dependent upon direction). Further complicating matters, there is typically a time-dependency to the relationship for compression and recovery, resulting in viscoelastic behavior. Hence both the amount and rate of compressive force applied can be expected to impact the outcome of stapling. DISCUSSION: The growth of the laparoscopic use of staples has increased the difficulty of device design, as precise control of compression is problematic in extended length staplers. Progressive firing along the cartridge and multi-stage compression have both been found to be beneficial in providing the uniform force needed to produce well-formed staples. Such technical advances can reduce stresses within the stapler, preventing deformation of the stapler arm and undesirable strain in the tissue. Current research includes understanding the effects of changing the rate of compression on staple formation with the hope that further improvements can be achieved in this ever-fruitful method of tissue apposition.

Economic Analysis of Leak Complications in Anastomoses Performed with Powered versus Manual Circular Staplers in Left-Sided Colorectal Resections: A US-Based Cost Analysis.

PURPOSE: To estimate the cost impact of using the ECHELON CIRCULAR™ Powered Stapler (ECP) compared with manual circular staplers (standard of care, SOC) among patients undergoing colectomy procedures that involve left-sided anastomosis. METHODS: A US hospital-based budget impact model was developed to estimate the impact of ECP in reducing the surgical complication of anastomotic leak. The incremental acquisition cost of ECP vs SOC was compared to the net potential savings from reduced complication costs. The model was based on complication rates from a recently published matching-adjusted indirect comparison (MAIC) that compared clinical and healthcare utilization outcomes of patients using ECP with those of a propensity score-matched retrospective SOC control cohort from a real-world clinical practice population. The model assessed total cost, average length of stay (LOS), proportion of patients with a non-home discharge, and all-cause readmission. Deterministic (DSA) and probabilistic sensitivity analyses (PSA) were conducted to evaluate the robustness of the model assumptions and inputs. RESULTS: Despite a higher device cost of $412 for ECP compared with $298 for a manual stapler, annual savings due to avoided complications with ECP was $53,987 for anastomotic leak, assuming 100 procedures per year with each type of circular stapler. ECP also helped to avoid 27 LOS days, 0.38 readmissions and 0.22 non-home discharges. Sensitivity analyses around potential drivers of costs established the robustness of economic savings with the use of ECP - with annual savings being most impacted by the probability of anastomotic leak complication in the DSA. CONCLUSION: This model demonstrates that among patients undergoing left-sided colectomy procedures, the incremental cost of using the ECHELON CIRCULAR™ Powered Stapler instead of a manual circular stapler was offset by the savings from lowered incidence and cost of management of anastomotic leaks in the hospital setting.