Control of a hybrid robotic system for computer-assisted interventions in dynamic environments

International audiencePurpose Minimally invasive surgery is becoming the standard treatment of care for a variety of procedures. Surgeons need to display a high level of proficiency to overcome the challenges imposed by the minimal access. Especially when operating on a dynamic organ, it becomes very difficult to align instruments reliably and precisely. In this paper, a hybrid ro-botic system and a dedicated robotic control approach are proposed to assist the surgeon performing complex surgical gestures in a dynamic environment. Methods The proposed hybrid robotic system consists of a rigid robot arm on top of which a continuum robot is mounted in series. The continuum robot is locally actuated with McKibben muscles. A control scheme is adopted based on quadratic programming framework. It is shown that this framework allows enforcing a set of constraints on the pose of the tip, as well as of the instrument shaft, which is commanded to slide in and out through the entry point. Results Through simulation and experiments it is shown how the robot tool-tip is able to follow sinus-oidal trajectories of 0.37 Hz and 2 Hz, corresponding to motion due to breathing and heartbeat respectively, while maintaining the instrument shaft pivoting nicely about the entry point. The positioning and tracking accuracy of such system is shown to lie below 3mm in position and 5 • in angle. Herbert De Praetere is with UZ Leuven, Cardiac surgery, Conclusion The results suggest a good potential for applying the proposed technology to assist the surgeon during complex robot-assisted interventions. It is also illustrated that even when using flexible hence relatively safe end-effectors, it is possible to reach acceptable tracking behaviour at relatively high frequencies

Chronic contained rupture of the posterior left ventricular wall two years after balloon dilatation of a degenerated mitral bioprosthesis

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Can a central stitch over the Arantius' nodules provide a solution for preoperative severe native AI in LVAD patients

Purpose: To evaluate the evolution of aortic valve insufficiency (AI) after Park's central stitch in patients with severe, preoperative, native aortic valve insufficiency.
Methods: We retrospectively studied 71 continuous flow LVAD patients between January 2004 and December 2010. Four patients with AI≥3/4 were treated with a central stitch. An intensive review of the literature was performed to debate the use of the central stitch in this population. 
Results: The AI at baseline (AI = 2.75 ± 0.5) and AI at last measurement (AI = 0.75 ± 0.65) is statistically different after central stitch (p<0.05) with mean follow up of 198.25 (± 146.70) days. Total cross clamp-time during the placement of the stitch was 15.5 minutes (± 13.062). CVA was not diagnosed in our cohort.
Conclusions: Park's central stitch can be successfully performed on patients with severe native AI (≥3/4) with good long-term results. Short ischemic time and simple application of the stitch are the biggest advantages. Due to the progression of AI in longstanding LVAD, the central stitch may be beneficial for LVAD in destination therapy. Since this is a small group of patients and also an early experience, more cases will be necessary to confirm these positive results.status: publishe

Starting minimally invasive valve surgery using endoclamp technology: safety and results of a starting surgeon

To critically review the learning curve, safety issues and outcome of a single surgeon while starting up minimally invasive mitral valve surgery (MIMVS).status: publishe

Low-Dose and Slow-Infusion Thrombolysis for Prosthetic Valve Thrombosis After a Transcatheter Valve in the Mitral Position

publisher: Elsevier articletitle: Low-Dose and Slow-Infusion Thrombolysis for Prosthetic Valve Thrombosis After a Transcatheter Valve in the Mitral Position journaltitle: JACC: Cardiovascular Interventions articlelink: http://dx.doi.org/10.1016/j.jcin.2017.01.033 content_type: article copyright: © 2017 by the American College of Cardiology Foundation. Published by Elsevier.status: publishe

Cost analysis of minimally invasive compared to conventional mitral valve surgery

© 2016, Acta Cardiologica. All rights reserved. Objective Minimally invasive cardiac surgery through port-access has been advocated as a valid alternative for conventional full sternotomy approaches. However, the full economic consequences are unclear. We undertook an analysis of our own data to address these uncertainties. Methods Retrospective data, on patients who underwent single mitral valve surgery (repair or replacement) were included in our analysis. These were allocated into two cohorts based upon the intended surgical approach: either port-access or full sternotomy. Propensity score matching was performed to avoid confounding factors. Comprehensive clinical and cost data, based on hospital charges and a cost allocation model, were collected. Results There were fewer complications with port-access versus full sternotomy. Operation times were longer but there was a shorter intensive care and total hospital stay. Port-access resulted in comparable overall costs (€ 21,041 ± 3,743 compared with € 23,999 ± 15,007 for full sternotomy; mean and standard deviation). A breakdown into accounting groups showed reductions in several costs categories (i.e. nursing costs, technical fees, and pharmacy drugs/implants) except for materials. Patient costs were higher for the port-access group due to higher material costs (€ 1,917 ± 602 versus € 1,145 ± 659; mean and standard deviation). From a hospital perspective direct costs were comparable in both cohorts. Conclusion Port-access mitral valve surgery in UZ Leuven has at least comparable short-term clinical results as full sternotomy. It is associated with comparable costs for the acute-treatment phase for the health insurance system and the hospital, but higher patient costs.status: publishe

Cost analysis of minimal invasive mitral valve repair

OBJECTIVE: Cardiac surgery was one of the last fields to conquer for minimal invasive surgery. Minimal access cardiac surgery trough port-access has been advocated to be a valid alternative for classic median sternotomy. In spite of its noticeable longer operation time and cross clamp time, a shorter hospital stay, less postoperative pain and a faster recovery are systematically described. The costs of mitral valve repair via port-access and full sternotomy were compared. METHODS: Patients who underwent single mitral valve surgery in UZ Leuven, between 2004 and 2011, were included. Two cohorts were formed based upon type of surgery: Full Sternotomy (FS) or Port-Access (PA). Clinical and cost data, based on hospital charges, were collected. Propensity score matching for preoperative risk factors was performed. RESULTS: Overall costs of minimal invasive mitral valve surgery (€21041 ± 3742) are significantly lower compared to sternotomy (€23999 ± 15006). Figure 1 depicts that for port-access nursing costs, medical-, and technical fees are lower. Pharmacy costs in this group are higher. Patients costs are higher for the port-access group, on average approximately €772. This is due to higher material costs. CONCLUSIONS: Port-Access is associated with longer surgical times, shorter intensive care stay, shorter hospitalization, less blood transfusions, and lower overall complication rates. Minimal invasive mitral valve repair is associated with lower costs for the society but a higher patient cost due to more expensive surgical tools.status: publishe