Correction to: Expected Budget Impact and Health Outcomes of Expanded Use of Vagus Nerve Stimulation Therapy for Drug-Resistant Epilepsy.

The article "Expected Budget Impact and Health Outcomes of Expanded Use of Vagus Nerve Stimulation Therapy for Drug-Resistant Epilepsy", written by Molly F. Purser, Deirdre M. Mladsi, Alan Beckman, Francesca Barion, John Forsey was originally published electronically on the publisher's internet portal (currently SpringerLink) on August 24, 2018 without open access.

Expected Budget Impact and Health Outcomes of Expanded Use of Vagus Nerve Stimulation Therapy for Drug-Resistant Epilepsy.

INTRODUCTION: The objective was to estimate, from the perspective of a managed care organization in the United States, the budget impact and effect on health outcomes of expanded use of vagus nerve stimulation [VNS (VNS Therapy®)] among patients aged ≥ 12 years with drug-resistant epilepsy (DRE) with partial-onset seizures. METHODS: An Excel model was developed to compare the costs of continued anti-epileptic drug (AED) treatment with the costs of VNS plus AED treatment. The number of people eligible for VNS was estimated using published prevalence data and an estimate of the percentage of eligible patients currently without VNS. Costs included VNS device, placement, programming, and battery changes; adverse events associated with VNS (cough, voice alteration, device removal resulting from surgical site infection); AEDs; and seizure-related costs affected by seizure frequency, which affects resource utilization (i.e., hospitalizations, emergency department visits, neurologist visits). To estimate the potential savings with VNS due to a reduction in seizure frequency, the budget impact model uses the results of an underlying Markov model to estimate seizure-related costs by seizure frequency. Transitions occurred among four health states, defined by number of seizures per month (i.e., seizure-free, ≤ 1, > 1 to < 10, ≥ 10) on a 3-month cycle based on published clinical trials and registry data. RESULTS: VNS resulted in an estimated net cost savings, on average, over 5 years, due to the expected reduction in seizure frequency. The initial cost of the VNS device, placement, and programming was estimated to be offset 1.7 years after VNS device placement. Reductions in hospitalizations were the main contributor to the cost savings with VNS. CONCLUSIONS: VNS is a proven intervention that offers a long-term solution for patients with DRE by reducing seizure frequency, which leads to lower resource utilization and lower costs. FUNDING: LivaNova PLC.

A novel shape memory alloy annuloplasty ring for minimally invasive surgery: design, fabrication, and evaluation.

A novel annuloplasty ring with a shape memory alloy core has been developed to facilitate minimally invasive mitral valve repair. In its activated (austenitic) phase, this prototype ring has comparable mechanical properties to commercial semi-rigid rings. In its pre-activated (martensitic) phase, this ring is flexible enough to be introduced through an 8-mm trocar and easily manipulated with robotic instruments within the confines of a left atrial model. The core is constructed of 0.50 mm diameter NiTi, which is maintained below its martensitic transition temperature (24 °C) during deployment and suturing. After suturing, the ring is heated above its austenitic transition temperature (37 °C, normal human body temperature) enabling the NiTi core to attain its optimal geometry and stiffness characteristics indefinitely. This article summarizes the design, fabrication, and evaluation of this prototype ring. Experimental results suggest that the NiTi core ring could be a viable alternative to flexible bands in robot-assisted minimally invasive mitral valve repair.

Evaluation of a shape memory alloy reinforced annuloplasty band for minimally invasive mitral valve repair.

PURPOSE: An in vitro study using explanted porcine hearts was conducted to evaluate a novel annuloplasty band, reinforced with a two-phase, shape memory alloy, designed specifically for minimally invasive mitral valve repair. DESCRIPTION: In its rigid (austenitic) phase, this band provides the same mechanical properties as the commercial semi-rigid bands. In its compliant (martensitic) phase, this band is flexible enough to be introduced through an 8-mm trocar and is easily manipulated within the heart. EVALUATION: In its rigid phase, the prototype band displayed similar mechanical properties to commercially available semi-rigid rings. Dynamic flow testing demonstrated no statistical differences in the reduction of mitral valve regurgitation. In its flexible phase, the band was easily deployed through an 8-mm trocar, robotically manipulated and sutured into place. CONCLUSIONS: Experimental results suggest that the shape memory alloy reinforced band could be a viable alternative to flexible and semi-rigid bands in minimally invasive mitral valve repair.