Catheter manipulation analysis for objective performance and technical skills assessment in transcatheter aortic valve implantation.

PURPOSE: Transcatheter aortic valve implantation (TAVI) demands precise and efficient handling of surgical instruments within the confines of the aortic anatomy. Operational performance and dexterous skills are critical for patient safety, and objective methods are assessed with a number of manipulation features, derived from the kinematic analysis of the catheter/guidewire in fluoroscopy video sequences. METHODS: A silicon phantom model of a type I aortic arch was used for this study. Twelve endovascular surgeons, divided into two experience groups, experts ([Formula: see text]) and novices ([Formula: see text]), performed cannulation of the aorta, representative of valve placement in TAVI. Each participant completed two TAVI experiments, one with conventional catheters and one with the Magellan robotic platform. Video sequences of the fluoroscopic monitor were recorded for procedural processing. A semi-automated tracking software provided the 2D coordinates of the catheter/guidewire tip. In addition, the aorta phantom was segmented in the videos and the shape of the entire catheter was manually annotated in a subset of the available video frames using crowdsourcing. The TAVI procedure was divided into two stages, and various metrics, representative of the catheter's overall navigation as well as its relative movement to the vessel wall, were developed. RESULTS: Experts consistently exhibited lower values of procedure time and dimensionless jerk, and higher average speed and acceleration than novices. Robotic navigation resulted in increased average distance to the vessel wall in both groups, a surrogate measure of safety and reduced risk of embolisation. Discrimination of experience level and types of equipment was achieved with the generated motion features and established clustering algorithms. CONCLUSIONS: Evaluation of surgical skills is possible through the analysis of the catheter/guidewire motion pattern. The use of robotic endovascular platforms seems to enable more precise and controlled catheter navigation.

The use of robotic endovascular catheters in the facilitation of transcatheter aortic valve implantation.

OBJECTIVES: The use of transcatheter aortic valve implantation (TAVI) is rapidly increasing with advances in technology and improved clinical outcomes. Adoption of robotic catheter technologies could have a role in TAVI, in different stages of the procedure, to improve endovascular tool manipulation and potentially reduce the risk of cerebral embolization. The aim was to determine whether there are advantages in using a robotic catheter for TAVI in the initial stages of the procedure; aortic arch navigation and valve crossing. METHODS: A silicone in vitro model of the aorta and stenotic aortic valve was developed. Fifteen operators performed the fluoroscopy-guided simulation using manual and robotic techniques. Performance metrics-time and vessel wall contact (wall-hits) were compared (Wilcoxon's signed-rank test). RESULTS: Overall, the time taken for robotic arch navigation was increased (3.09 min interquartile range (1.24-6.29) vs 1.21 min (0.15-4.42); P = 0.03). Contact with the aortic arch wall, however, significantly decreased using the robotic catheter: wall-hits 1 (0-5) vs 6 (2-22), P < 0.01. For valve crossing, there was no significant increase in time and wall-hits when using the robotic technology. CONCLUSIONS: Use of robotic catheter technology is feasible in the initial stages of TAVI. Although it takes longer, robotic navigation reduces contact with the aortic arch wall, potentially reducing the embolic risk during endovascular manipulation. Using a robotic catheter is possible without increasing the number of wall-hits during valve crossing. This may provide a stable platform for wire positioning in the ventricle. With improvements in technology, perhaps allowing valve deployment, the stability and accuracy of the robotic arm may further improve performance.

In patients with post-sternotomy mediastinitis is vacuum-assisted closure superior to conventional therapy?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether vacuum-assisted closure therapy (VAC) is superior to conventional therapy for treating post-sternotomy mediastinitis. Altogether >261 papers were found using the reported search, of which 9 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Several studies indicate that VAC therapy is associated with shorter lengths of intensive care and in-hospital stay as well as faster rates of wound healing and fewer dressing changes. It has also been shown that VAC therapy is correlated with a statistically significant reduction in reinfection rates, particularly those that occur in the early postoperative period (at the 1-week follow-up). Patients can be discharged with the dressing in situ and managed in the community with a view to delayed closure or reconstruction. However, the studies comparing VAC with conventional therapy are all retrospective in nature and reinforce the need for randomized controlled trials in order to more accurately establish differences in outcomes between VAC and conventional therapy. Additionally, owing tlo the variability of treatment protocols within the non-VAC arm, it is more challenging to draw definitive conclusions regarding the superiority of VAC therapy to every modality that is considered conventional treatment. We conclude that VAC therapy is a portable and an increasingly economical option for the treatment of post sternotomy mediastinitis. Although reductions in mortality rates were not reproduced in all studies, evidence suggests that VAC should still be considered as a first-line therapy for post-sternotomy mediastinitis and as a bridge therapy to musculocutaneous reconstruction or primary closure.

Tissue engineering: revolution and challenge in auricular cartilage reconstruction.

External ear reconstruction for congenital deformity such as microtia or following trauma remains one of the greatest challenges for reconstructive plastic surgeons. The problems faced in reconstructing the intricate ear framework are highly complex. A durable, inert material that is resistant to scar contracture is required. To date, no material, autologous or prosthetic, is available that perfectly mimics the shapely elastic cartilage found in the ear. Current procedure involves autologous costal cartilage that is sculpted to create a framework for the overlying soft tissues. However, this is associated with donor-site morbidity, and few surgeons worldwide are skilled in the techniques required to obtain excellent results. Various alloplastic materials have therefore been used as a framework. However, a degree of immunogenicity and infection and extrusion are inevitable, and results are often disappointing. Tissue-engineered cartilage is an alternative approach but, despite significant progress in this area, many problems remain. These need to be addressed before routine clinical application will become possible. The current tissue-engineered options are fragile and inflexible. The next generation of auricular cartilage engineering is promising, with smart materials to enhance cell growth and integration, and the application of stem cells in a clinical setting. More recently, the authors' team designed the world's first entirely synthetic trachea composed of a novel nanocomposite material seeded with the patient's own stem cells. This was successfully transplanted in a patient at the Karolinska Hospital in Sweden and may translate into a tissue-engineered auricle in the future.

Tissue-engineered heart valve: future of cardiac surgery.

BACKGROUND: Heart valve disease is currently a growing problem, and demand for heart valve replacement is predicted to increase significantly in the future. Existing "gold standard" mechanical and biological prosthesis offers survival at a cost of significantly increased risks of complications. Mechanical valves may cause hemorrhage and thromboembolism, whereas biologic valves are prone to fibrosis, calcification, degeneration, and immunogenic complications. METHODS: A literature search was performed to identify all relevant studies relating to tissue-engineered heart valve in life sciences using the PubMed and ISI Web of Knowledge databases. DISCUSSION: Tissue engineering is a new, emerging alternative, which is reviewed in this paper. To produce a fully functional heart valve using tissue engineering, an appropriate scaffold needs to be seeded using carefully selected cells and proliferated under conditions that resemble the environment of a natural human heart valve. Bioscaffold, synthetic materials, and preseeded composites are three common approaches of scaffold formation. All available evidence suggests that synthetic scaffolds are the most suitable material for valve scaffold formation. Different cell sources of stem cells were used with variable results. Mesenchymal stem cells, fibroblasts, myofibroblasts, and umbilical blood stem cells are used in vitro tissue engineering of heart valve. Alternatively scaffold may be implanted and then autoseeded in vivo by circulating endothelial progenitor cells or primitive circulating cells from patient's blood. For that purpose, synthetic heart valves were developed. CONCLUSIONS: Tissue engineering is currently the only technology in the field with the potential for the creation of tissues analogous to a native human heart valve, with longer sustainability, and fever side effects. Although there is still a long way to go, tissue-engineered heart valves have the capability to revolutionize cardiac surgery of the future.

Gold revolution--gold nanoparticles for modern medicine and surgery.

Nanotechnology is a new and exciting branch of science which offers enormous potential for development of medicine and surgery. Gold nanoparticles (GNP) is just one of a variety of nano products which will be available for physician of the future. GNP will give us more effective treatments and diagnosis. We are able to conjugate GNP with peptides, drugs, and other molecules to gain astonishing effects. High quality, non-invasive imaging will inevitably lead to astonishing accuracy diagnostic tools with effective use during surgery. The same principles may be used in the future for drug delivery and thermal treatment of cancer. Detailed DNA detection and regulation may become everyday use technology, in medicine with support from GNP based tools. Bacterial diagnostics and nerve repair are relatively poorly researched areas of application of GNP with possibly astonishing therapeutic effects. Non-invasive clearance of arteriosclerotic plagues with GNP shows a great prospect for further development of minimally invasive surgery. However, before all of those tools will become available for clinicians, in depth toxicology research as well as transitional research and design have to be done to ensure safe clinical practice with maximal benefit for patients.