“Image guidance for robotic minimally invasive coronary artery bypass.”
Figl, M., D. Rueckert, et al. (2009).
Comput Med Imaging Graph.
A novel system for image guidance in totally endoscopic coronary artery bypass (TECAB) is presented. Key requirement is the availability of 2D-3D registration techniques that can deal with non-rigid motion and deformation. Image guidance for TECAB is mainly required before the mechanical stabilisation of the heart, when the most dominant source of misregistration is the deformation and non-rigid motion of the heart. To augment the images in the endoscope of the da Vinci robot, we have to find the transformation from the coordinate system of the preoperative imaging modality to the system of the endoscopic cameras. In a first step we build a 4D motion model of the beating heart. Intraoperatively we can use the ECG or video processing to determine the phase of the cardiac cycle, as well as the heart and respiratory frequencies. We then take the heart surface from the motion model and register it to the stereo endoscopic images of the da Vinci robot resp. of a validation system using photo-consistency. To take advantage of the fact that there is a whole image sequence available for registration, we use the different phases together to get the registration. We found the similarity function to be much smoother when using more phases. This also showed promising behaviour in convergence tests. Images of the vessels available in the preoperative coordinate system can then be transformed to the camera system and projected into the calibrated endoscope view using two video mixers with chroma keying. It is hoped that the augmented view can improve the efficiency of TECAB surgery and reduce the conversion rate to more conventional procedures.
“Small-incision mitral valve repair: Safe, durable, and approaching perfection.”
Gammie, J. S., S. T. Bartlett, et al. (2009).
Annals of Surgery 250(3): 409-414.
OBJECTIVE:: To critically evaluate an initial experience with small-incision mitral valve operation with respect to safety, durability, and effectiveness. SUMMARY BACKGROUND DATA:: Mitral valve (MV) surgery is dominated by a sternotomy approach, with MV repair rates which average 60%. Advantages of valvular repair compared with replacement include lower operative and long-term mortality, decreased stroke and infection risks, and superior freedom from reoperation and complications of anticoagulation. METHODS:: Right chest small-incision MV surgery was performed on 187 consecutive patients. Outcomes including operative mortality and major morbidity were recorded. All patients underwent predismissal echocardiography in a core laboratory. RESULTS:: Between 2003 and 2008, 57% (187/327) of isolated MV operations were performed using an anterolateral 6 cm 4th intercostal space small-incision. Operative techniques included femoral arterial and venous plus internal jugular cannulation and direct aortic cross-clamping. Pathology of the anterior leaflet was present in 22%, and PTFE neochordal repairs were used in 36% of cases. The rate of MV repair was 96.3% (180/187) and was 100% for patients with degenerative disease. Median cardiopulmonary bypass and aortic cross-clamp times were 108 and 82 minutes, respectively. There were no deaths, strokes, renal failure, or wound infections. Two patients (1.1%) were re-explored for bleeding, and 27% received blood transfusions. The median hospital stay was 4 days. Clinical core laboratory-assessed freedom from significant (MR > mild) at hospital discharge was 99%. Survival at a median follow-up of 2.5 years was 99%. CONCLUSIONS:: Direct visualization of the mitral valve through a right chest small-incision enables safe and effective performance of complex MV repair, with repair rates in excess of 95%. Copyright © 2009 by Lippincott Williams & Wilkins.
“An Alternative Method for Cardioplegia Delivery during Totally Endoscopic Robotic Surgery.”
Guden, M., A. A. Korkmaz, et al. (2009).
J Card Surg.
Abstract The optimal technique for myocardial protection and cardioplegia delivery during totally endoscopic robotic surgery is still under evolution. Cardioplegia delivery with endovascular clamping of the aorta is a common method used for this purpose but has several disadvantages and may lead to serious complications. Here we describe an alternative cardioplegia delivery method during totally endoscopic atrial septal defect closure and mitral valve repair. The method using a transthoracic aortic clamp and an antegrade cardioplegia cannula without any thoracotomy seems to be a safe and reproducible technique, which may enhance myocardial protection and prevent some of the complications of the endoclamp technique during robotically assisted cardiac surgery. (J Card Surg ****;**:**-**).
“Robot-assisted cardiac surgery.”
Modi, P., E. Rodriguez, et al. (2009).
Interactive Cardiovascular and Thoracic Surgery 9(3): 500-505.
Recognition of the significant advantages of minimizing surgical trauma has resulted in a substantial increase in the number of minimally invasive (MI) cardiac surgical procedures being performed. Synchronously, technological advances in optics, instrumentation and perfusion technology have facilitated routine totally endoscopic robotic cardiac surgery using the da Vinci® telemanipulation system (Intuitive Surgical Inc). This technology has been applied to many cardiac surgical procedures, in particular, mitral valve repair (MVP) and totally endoscopic coronary artery bypass grafting (TECAB), allowing the surgeon to operate through 5 mm port sites rather than a traditional median sternotomy. In this rapidly evolving field, we review the clinical results of robotic cardiac surgery.
“Is the Anterior Intertrigonal Distance Increased in Patients With Mitral Regurgitation Due to Leaflet Prolapse?”
Suri, R. M., J. Grewal, et al. (2009).
Annals of Thoracic Surgery 88(4): 1202-1208.
Background: Severe mitral regurgitation (MR) leads to progressive enlargement of left ventricular dimensions and, consequently, the mitral valve (MV) annulus. Data from animal and cadaver studies suggest that the mitral annulus may dilate asymmetrically in certain conditions, which may influence the choice of valve repair technique. Although it is generally accepted that the posterior mitral annulus dilates in patients with severe MR due to leaflet prolapse, the stability of the anterior intertrigonal distance has not yet been demonstrated in humans. Methods: We obtained real-time, three-dimensional (3D) transesophageal echocardiographic images of the MV in 44 patients: 29 patients scheduled to undergo MV repair for severe MR due to leaflet prolapse (MV disease group) and 15 normal outpatients undergoing evaluation for various reasons (control group). Mitral valve repair was performed by median sternotomy or minimally invasively using thoracoscopic or robotic assistance. All patients underwent implantation of a standard-length flexible 63-mm posterior annuloplasty band at the time of mitral repair and we obtained postoperative 3D images for 11 patients after separation from bypass. Mitral annular dimensions were measured throughout the cardiac cycle using reconstructive analysis software (QLAB MVQ Version 6.0; Phillips, Bothell, WA). Results: The mean patient age was 60 years; 30 were men. The mean ejection fraction was 0.61 and was similar between the two groups (p = 0.16). In patients with MR due to leaflet prolapse, posterior annular length and total annular circumference were significantly larger than in control patients (p < 0.001). In contrast, there was no detectable difference in the anterior intertrigonal distance between patients with MR and normal controls. After mitral valve leaflet repair and posterior annuloplasty there was a significant decrease in both the total annular circumference and posterior annular length (p < 0.0001) while cyclic annular contraction was preserved. Conclusions: Although the posterior mitral annulus is enlarged in patients with significant MR due to degenerative leaflet prolapse, there is no evidence that the intertrigonal distance is abnormal in these patients. Our data support the conclusion that posterior annular reduction with a flexible device at the time of mitral valve repair is important, and that altering the anterior intertrigonal portion of the mitral annulus is unnecessary. © 2009 The Society of Thoracic Surgeons.