Development of robotic enhanced endoscopic surgery for the treatment of coronary artery disease

Robotic-assisted coronary artery bypass grafting: current knowledge and future perspectives

Minimally invasive direct coronary artery bypass grafting (MIDCAB) and totally endoscopic coronary artery bypass grafting (TECAB) are the two existing strategies for robotic-assisted, surgical myocardial revascularization. In this review, we summarize the wide evidence available in the literature regarding the benefits of these two procedures, and detail the technical skills required to master robotic coronary surgery techniques.

Patient-specific access planning in minimally invasive mitral valve surgery

BACKGROUND

Minimally invasive mitral valve repair or replacement (MIMVR) approaches have been increasingly adopted for the treatment of mitral regurgitation, allowing a shorter recovery time and improving postoperative quality of life. However, inadequate positioning of the right mini thoracotomy access (working port) translates into suboptimal exposure, prolonged operative times and, potentially, reduction in the quality of mitral repair. At present, we are missing tools to further improve the positioning of the working port in order to ameliorate surgical exposure in a patient- specific fashion.

METHODS AND EVALUATION OF THE HYPOTHESIS

We hypothesized that computation of relevant anatomical measurements from preoperative CT scans in patients undergoing MIMVR may provide patient-specific information in order to propose the surgical access that best fits to the patient's morphology. We hypothesized that this may systematize optimal mitral valve exposure, facilitating the procedure and potentially ameliorating the outcomes. We also hypothesized that preoperative simulation of the working port site and surgical instruments' insertion using a three-dimensional virtual model of the patient is feasible and may help in the customization of ports positioning. The hypothesis was evaluated by a multidisciplinary team including cardiac surgeons, experts in medical image processing and biomedical engineers. CT scans of 14 patients undergoing MIMVR were segmented to visualize 3D chest bones and heart structures meshes. The mitral valve annulus is pointed manually by the expert or extracted automatically when contrast-enhanced CT scan was available. The valve plane was then calculated and the optimal incision location analyzed according to a) the perpendicularity and b) the distance between the intercostal spaces and the valve plane. An angle-chart representation for the 4th, 5th and 6th intercostal spaces and a color map illustrating the distance between the skin and the mitral valve were created. We started the development of a simulation tool for preoperative planning using 3D Slicer software.

CONCLUSIONS

Several patient-specific factors (including the orientation of the mitral valve plane and the morphology of the chest cage) may influence the performance of a MIMVR procedure, but they are not quantitatively considered in the current planning strategy. We suggest that the clinical results of MIMVR can be improved through preoperative virtual simulation and computer-assisted surgery (through determination of working port and surgical instruments insertion positioning). Further research is justified and the development of a software tool for clinical evaluation is warranted to verify the current hypothesis.

Recent Advances in Treatment of Coronary Artery Disease: Role of Science and Technology

Coronary artery disease (CAD) is one of the most common causes of death worldwide. In the last decade, significant advancements in CAD treatment have been made. The existing treatment is medical, surgical or a combination of both depending on the extent, severity and clinical presentation of CAD. The collaboration between different science disciplines such as biotechnology and tissue engineering has led to the development of novel therapeutic strategies such as stem cells, nanotechnology, robotic surgery and other advancements (3-D printing and drugs). These treatment modalities show promising effects in managing CAD and associated conditions. Research on stem cells focuses on studying the potential for cardiac regeneration, while nanotechnology research investigates nano-drug delivery and percutaneous coronary interventions including stent modifications and coatings. This article aims to provide an update on the literature (in vitro, translational, animal and clinical) related to these novel strategies and to elucidate the rationale behind their potential treatment of CAD. Through the extensive and continued efforts of researchers and clinicians worldwide, these novel strategies hold the promise to be effective alternatives to existing treatment modalities.

The state of robotic cardiac surgery in Europe

BACKGROUND

In the past two decades, the introduction of robotic technology has facilitated minimally invasive cardiac surgery, allowing surgeons to operate endoscopically rather than through a median sternotomy. This approach has facilitated procedures for several structural heart conditions, including mitral valve repair, atrial septal defect closure and multivessel minimally invasive coronary artery bypass grafting. In this rapidly evolving field, we review the status of robotic cardiac surgery in Europe with a focus on mitral valve surgery and coronary revascularization.

METHODS

Structured searches of MEDLINE, Embase, and Cochrane databases were performed from their dates of inception to June 2016. All original studies, except case-reports, were included in this qualitative review. Studies performed in Europe were presented quantitatively. Data provided from Intuitive Surgical Inc. are also presented.

RESULTS

Fourteen papers on coronary surgery were included in the analysis and reported a mortality rate ranging between 0-1%, revision for bleeding between 2-7%, conversion to a larger incision between 2-15%, and patency rate between 92-98%. The number of procedures ranged between 23 and 170 per year. There were only a small number of published reports for robotic mitral valve surgery from European centers.

CONCLUSIONS

Coronary robotic surgery in Europe has been performed safely and effectively with very few perioperative complications in the last 15 years. On the other hand, mitral surgery has been developed later with increasing applications of this technology only in the last 5-6 years.

The midterm outcome and MACE of robotically enhanced grafting of left anterior descending artery with left internal mammary artery

BACKGROUND

We assessed the midterm outcome and the incidence of major adverse cardiovascular events in UK's largest Da Vinci assisted robotic coronary revascularisation cohort. This study was set up at the Imperial College NHS Trust, St. Mary's Hospital, London, United Kingdom.

METHOD

Benchmarking approach through retrospective audit of the regional outcomes against standards in the published literature. Data was collected from the patient's records, communication with the primary care physicians and the national strategic tracing service. The results were compared with the published literature. Patients who underwent robotic assisted coronary revascularisation were included. Other robotic procedures or minimally invasive revascularisation without the use of the Da Vinci robot were excluded. The main outcome measure was the midterm survival up to five years and the incidence of major adverse cardiovascular events (MACE) up to three years.

RESULTS

Since April 2002, one hundred consecutive patients underwent either off pump robotic assisted single vessel small thoracotomy (SVST, n=88), or off pump total endoscopic coronary artery bypass grafting (TCAB, n=12). All patients were operated on by the same primary surgeon but different assisting surgeons. All patients received a left internal mammary arterial (LIMA) graft as planned. The primary outcome of total one month and three years MACE and up to five year survival was 0, 9 and 96% respectively.

CONCLUSIONS

The procedural success rates in terms of morbidity and mortality up to five years are compatible to the outcomes observed outside the United Kingdom. These results are not inferior to that of conventional off pump single vessel coronary surgery or percutaneous coronary intervention to the LAD.

Defining the Learning Curve for Robotic-Assisted Endoscopic Harvesting of the Left Internal Mammary Artery

Objective

Robotic-assisted techniques are continuing to cement their role in coronary surgery, particularly in facilitating the endoscopic harvesting of the left internal mammary artery (LIMA), regardless of how the subsequent bypass grafting is performed. As more surgeons attempt to become trained in robotic-assisted procedures, we sought to better define the learning curve associated with robotic-assisted endoscopic LIMA harvest.

Methods

Between January 2011 and July 2012, a total of 77 patients underwent robotic-assisted minimally invasive direct coronary artery bypass surgery at our institution. The LIMA was harvested endoscopically in all patients, using standard robotic instruments, followed by direct grafting to anterior wall myocardial vessels via a small thoracotomy. Intraoperative times for various components of the procedure were collated and analyzed.

Results

The mean ± SD time taken to insert and position the ports for the robotic instruments was 3.9 ± 1.4 minutes. The mean ± SD LIMA harvest time was 31.8 ± 10.1 minutes, and the mean ± SD total robotic time was 44.2 ± 12.9 minutes. All time variables consistently continued to decrease as the experience of the operating surgeon increased, with the greatest magnitude of improvement being evident within the first 20 cases. The logarithmic learning curves for LIMA harvest time and total robot time during our entire experience were both calculated as 90%, correlating to an expected 10% improvement in performance for each doubling of cases completed.

Conclusions

Coronary surgeons can rapidly become proficient in robotic-assisted endoscopic LIMA harvest, with significant improvement in operative times evident within the first 20 cases completed. These data may be useful in designing appropriate training programs for newer surgeons seeking to gain experience in robotic-assisted coronary surgery.

Hypoxemia during one-lung ventilation for robot-assisted coronary artery bypass graft surgery

BACKGROUND

Robot-assisted coronary artery bypass grafting requires continuous one-lung ventilation (OLV) to evacuate the thoracic cavity. Whether this ventilatory mode subjects patients to serious hypoxemia remains underinvestigated.

METHODS

From 2005 to 2010, all patients receiving robot-assisted coronary artery bypass graft surgery using OLV with active capnothorax for internal mammary artery harvesting and then passive pneumothorax for minithoracotomy direct-vision coronary bypass graft surgery were included. Patients' variables of oxygenation were monitored and compared throughout the whole surgical period. Persistent oxygen desaturation (arterial oxygen pressure <70 mm Hg) refractory to primary managements was defined as a hypoxemic event, and predictors of such events were identified by multivariate regression analysis.

RESULTS

A total of 255 consecutive patients were enrolled. Average oxygen saturation decreased modestly during the first stage of OLV with active capnothorax, causing hypoxemic events in 9 patients (4.3%) leading to death in 2 (0.8%), whereas it dropped drastically in the second stage of OLV with passive pneumothorax, resulting in hypoxemic events in 32 patients (12.6%) and death in 1 (0.4%). Multivariate regression analysis identified high pulmonary vascular resistance and low left ventricular ejection fraction as predictors of hypoxemia during internal mammary artery takedown, whereas prolonged procedure and chronic obstructive pulmonary disease were identified as predictors during minithoracotomy bypass grafting.

CONCLUSIONS

Robot-assisted two-stage coronary artery bypass surgery employing OLV could be complicated by serious hypoxemia especially at the minithoracotomy grafting stage and in patients with specific risk factors. Thus, when managing such patients, invasive monitoring and aggressive treatment of arterial desaturation are mandatory to ensure the patient's safety and procedural smoothness.

Robotic surgery in gynecology: an updated systematic review

The introduction of da Vinci Robotic Surgery to the field of Gynecology has resulted in large changes in surgical management. The robotic platform allows less experienced laparoscopic surgeons to perform more complex procedures. In general gynecology and reproductive gynecology, the robot is being increasingly used for procedures such as hysterectomies, myomectomies, adnexal surgery, and tubal anastomosis. Among urogynecology the robot is being utilized for sacrocolopexies. In the field of gynecologic oncology, the robot is being increasingly used for hysterectomies and lymphadenectomies in oncologic diseases. Despite the rapid and widespread adoption of robotic surgery in gynecology, there are no randomized trials comparing its efficacy and safety to other traditional surgical approaches. Our aim is to update previously published reviews with a focus on only comparative observational studies. We determined that, with the right amount of training and skill, along with appropriate patient selection, robotic surgery can be highly advantageous. Patients will likely have less blood loss, less post-operative pain, faster recoveries, and fewer complications compared to open surgery and potentially even laparoscopy. However, until larger, well-designed observational studies or randomized control trials are completed which report long-term outcomes, we cannot definitively state the superiority of robotic surgery over other surgical methods.

Effectiveness and safety of total endoscopic left internal mammary artery bypass graft to the left anterior descending artery

Totally endoscopic coronary artery bypass grafting (CABG) has become a feasible option using robotic technology and remote access perfusion techniques. The aim of this study was to determine the progression of the procedure's performance in the currently largest single-center series of arrested-heart totally endoscopic CABG. From 2001 to 2007, arrested-heart totally endoscopic CABG was performed in 100 patients (median age 59 years, range 46 to 70; 81 men, 19 women). All patients received left internal mammary artery grafts to the left anterior descending artery using the da Vinci Surgical System. Remote-access femoral perfusion and aortic balloon endo-occlusion were used in all patients. The series was divided into 4 phases: phase 1 (patients 1 to 25), phase 2 (patients 26 to 50), phase 3 (patients 51 to 75), and phase 4 (patients 76 to 100). The conversion rates to larger thoracic incisions were 7 of 25 (28%) in phase 1, 2 of 25 (8%) in phase 2, 1 of 25 (4%) in phase 3, and 1 of 25 (4%) in phase 4 (p = 0.018). Operative times and hospital stays decreased significantly with each subsequent phase, and clinical outcome showed corresponding improvements. There was no perioperative mortality. For the whole patient series, 5-year postoperative survival, freedom from angina, and freedom from major adverse cardiac and cerebral events were 100%, 91%, and 89%, respectively. In conclusion, after an initial steep learning curve, completely endoscopic left internal mammary artery-to-left anterior descending CABG can be performed safely, with low conversion rates. The learning curve for operative times and improvements in clinical outcome continued even at 100 procedures.

Robotic right gastroepiploic artery harvesting

OBJECTIVE

: Robotic surgery promises to extend the capabilities of the minimally invasive surgeon, and many surgical specialties are applying this new technology. However, there is no report of robotic harvesting of the right gastroepiploic artery (rGEA). We evaluated the possibility of video-endoscopic dissection of the rGEA using the da Vinci surgical system for use in minimally invasive coronary artery bypass surgery.

METHODS

: The procedure was performed on a porcine rGEA harvesting model using the Tuebingen MIS-Trainer and a pig model. In the pig model, a pneumoperitoneum (maximal pressure, 12 mm Hg) was established after the insertion of a 12-mm trocar (camera) using the open method. The surgical cart was positioned at the head of the pig. A 30-degree three-dimensional camera, using two parallel-arranged three-chip cameras, was inserted and mounted on the middle 12-mm trocar. Under direct visualization, the two lateral surgical arm trocars were then placed at both sides of the camera port. We mounted a permanent cautery hook and Cadiere forceps on the right and left surgical arm, respectively.

RESULTS

: We performed harvesting of the rGEA with the permanent cautery hook and Cadiere forceps mounted on the surgical arms. The rGEA were easily visualized and dissection with complete mobilization was achieved without injury in both models. The bleeding from the branch of the rGEA was prevented by use of the permanent cautery hook in the pig model.

CONCLUSIONS

: We have preliminarily established, in pig, the feasibility of robotic rGEA harvesting without laparotomy, avoiding the risks of abdominal complications and expanding its use for all patients. However, further studies need to be undertaken to prove its practical feasibility in humans using the da Vinci surgical system to make it an effective operation.

Robotic Technology—Probably a Safe Tool for Development of Completely Endoscopic Coronary Revascularization Procedures

Background

Totally endoscopic coronary artery bypass grafting (TECAB) requires telemanipulation technologies because attempts using conventional thoracoscopic instrumentation have completely failed. These complex operations require individual and team learning curves and necessitate a stepwise approach. The aim of this study is to assess risk adjusted outcome in robotically assisted coronary artery bypass grafting (CABG) after the first 6 years of application.

Methods

From 2001 to 2007, 177 CABG procedures were performed using the da Vinci system. A low risk patient population [age 59 (31–76) years, EuroSCORE 1 (0–7)] was treated. The following procedures were carried out: endoscopic internal mammary artery takedown in minimally invasive direct coronary artery bypass, Off-pump coronary artery bypass, and CABG (n = 26); robotic suturing of left internal mammary artery to left anterior descending artery anastomoses through sternotomy (n = 32); TECAB on the arrested heart (n = 108); TECAB on the beating heart (n = 11).

Results

There was no hospital mortality, and cumulative risk adjusted mortality plots showed that 2.76 predicted events did not occur. Given 177 event free procedures Clopper Pearson estimations revealed a 95% confidence interval between 0.0% and 2.3% for perioperative mortality.

Conclusions

Introduction of robotic TECAB grafting appears to meet current CABG safety standards. Initial application in low risk patients and a stepwise approach towards completely endoscopic versions of the operation are worthwhile. Despite a high grade of innovation and despite learning curves, perioperative mortality may be lower than predicted.

Robotic Endoscopic Left Internal Mammary Artery Harvesting: What Have We Learned After 100 Cases?

BACKGROUND

The development of robotic devices has recently offered the possibility of performing coronary artery bypass graft surgery (CABG) in a totally endoscopic way. An important step of this procedure is endoscopic harvesting of the left internal mammary artery (LIMA). It was the aim of our study to find factors influencing LIMA harvesting time and to describe the challenges associated with robotic endoscopic LIMA harvesting.

METHODS

From June 2001 to December 2005, a total of 100 patients underwent robotically assisted CABG. In all cases, the LIMA was harvested by using the robotic DaVinci device. Coronary artery bypass grafting procedures were completed through sternotomy, minithoracotomy, or in a totally endoscopic fashion.

RESULTS

The median LIMA harvesting time was 48 minutes (19 to 180). A significant learning curve was observed: y (min) = 151 - 26 x ln (x), x = LIMA takedown number, p less than 0.001. Takedown time decreased from 140 minutes in the first 10 cases to 34 minutes in the last 10 cases. There was no independent demographic factor that significantly influenced the LIMA harvesting time. The LIMA takedown time also showed no significant correlation with thorax dimensions. Injury to the LIMA occurred in 3 patients (6%) during the first half of the experience and in 1 patient (2%) during the second half (p = not significant).

CONCLUSIONS

Robotic-enhanced LIMA takedown is a prerequisite for totally endoscopic CABG. After passing through a significant learning curve, IMA takedown can be performed safely and within an acceptable time frame. Demography and chest size do not seem to influence IMA harvesting time. The rate of LIMA injuries is within the limits of conventional thoracoscopic harvesting.

Do manual assisting maneuvers increase speed and technical performance in robotically sutured coronary bypass graft anastomoses?

BACKGROUND

Robotic endoscopic coronary artery bypass grafting procedures usually are performed as solo surgery operations. This study aimed to investigate whether manual assistance can reduce suturing times and anastomotic suturing problems in robotic coronary artery surgery.

METHODS

In isolated pig hearts, the right coronary artery was excised from the epicardium as a pedicle. This pedicled vessel, which resembles the internal mammary artery, was sutured to the left anterior descending artery using the daVinci telemanipulation system. The anastomosis was performed in a running fashion using 7/0 Pronova. In group 1 (n = 20), the suture was performed by the console surgeon as a solo operation. In group 2 (n = 20), the anastomosis was assisted by a team member using an endo forceps. The operations were performed by five surgeons of different training levels.

RESULTS

The overall anastomotic time was 24 +/- 15 min in group 1 and 22 +/- 12 min in group 2. The difference was not significant. The rate for anastomotic suturing problems (thread rupture, knot formation, sling formation, needle bending) was 8 in 20 (40%) in group 1 and 8 in 20 (40%) in group 2 (no difference). Anastomotic times and anastomotic suturing errors were dependent on surgeon experience. All anastomoses in both groups showed correct suture alignment and were probe patent.

CONCLUSION

In a wet lab model of robotic coronary anastomoses, assisting maneuvers do not decrease suturing speed. Similar suturing quality can be achieved whether the suture is performed in a solo fashion or in an assisted manner.

Recent Trends in Minimally Invasive Cardiac Surgery

Evolving technologies have resulted in an increase in minimally invasive cardiac surgery. Currently, robotic systems allow surgeons to perform a variety of procedures through small incisions. This changing paradigm is reviewed.

Robotic cardiovascular surgery

Cardiovascular surgery has traditionally been performed through a median sternotomy, allowing the surgeon generous access to the heart and surrounding great vessels. Recently, less invasive methods have been developed to allow the surgeon the same amount of dexterity and accessibility to the heart, thus resulting in a paradigm shift in cardiac surgery. Originally, long instruments without pivot points were used, however; with the application of robotic telemanipulation systems that allow for improved dexterity, the surgeon is able to perform cardiac surgery from a distance not previously possible. In this rapidly evolving field, this article reviews the recent history and clinical results of robotics in cardiovascular surgery.

Robotically assisted totally endoscopic atrial septal defect repair: insights from operative times, learning curves, and clinical outcome

BACKGROUND

Remote access perfusion and robotics have enabled totally endoscopic closure of atrial septal defect and patent foramen ovale. The aim of this study was to address learning curve issues of totally endoscopic atrial septal defect repair on the basis of a single-center experience and to investigate whether long cardiopulmonary bypass and aortic occlusion times influence intraoperative and postoperative outcomes.

METHODS

Seventeen patients (median age, 35 years; range, 16 to 55 years) underwent totally endoscopic atrial septal defect repair using remote access perfusion and robotic technology (da Vinci telemanipulation system). Learning curves were assessed by means of regression analysis with logarithmic curve fit. The effect of operative variables on clinical outcome was analyzed by linear regression using the Spearman's rho coefficient.

RESULTS

No operative mortality or serious surgical complications were observed. No residual shunt was detected at intraoperative or postoperative echocardiography. Significant learning curves were noted for total operative time: y(min) = 406 - 49 ln(x) (r2 = 0.725; p = 0.002); cardiopulmonary bypass time: y(min) = 225 - 42 ln(x) (r2 = 0.699; p = 0.003); and aortic occlusion time: y(min) = 117 - 25 ln(x) (r2 = 0.517; p = 0.04), x = number of procedures. Median ventilation time, intensive care unit stay, and hospital length of stay were 7 hours (range, 2 to 19 hours), 26 hours (range, 15 to 120 hours), and 8 days (range, 5 to 14 days), respectively. No correlation was detected between cardiopulmonary bypass time and intubation time (r2 = 0.283; p = 0.326), intensive care unit stay (r2 = -0.138; p = 0.639), or total length of stay (r2 = 0.013; p = 0.962).

CONCLUSIONS

Totally endoscopic atrial septal defect repair can be performed safely, and learning curves for operative times are steep. Longer cardiopulmonary bypass times had no negative impact on intraoperative and postoperative outcome.

Technical challenges in totally endoscopic robotic coronary artery bypass grafting

OBJECTIVE

Robotic technology is a prerequisite for performance of totally endoscopic coronary artery bypass grafting. During the implementation phase of totally endoscopic coronary artery bypass, surgeon-related technical difficulties might be encountered. It was the aim of this study to assess the incidence of these challenges, to find risk factors, and to describe clinical results associated with technical errors.

METHODS

From October 2001 through October 2004, 40 patients received robotically assisted totally endoscopic left internal thoracic artery grafts to the left anterior descending coronary artery system with the da Vinci telemanipulation device. All patients underwent remote access cardiopulmonary bypass perfusion through groin access, and all anastomoses were performed on the arrested heart.

RESULTS

Undesirable technical events of various grades occurred in 20 (50%) of 40 patients: bleeding from a port hole in 3 (8%), left internal thoracic artery damage in 3 (8%), epicardial lesion in 3 (8%), remote access perfusion problems in 9 (23%), bleeding from the anastomosis in 4 (10%), and anastomotic stenosis in 2 (5%). There was no hospital mortality. The following differences were noted between patients without technical difficulties (group 1) and those in whom problems occurred (group 2): total operative time of 314 minutes (260-540 minutes) versus 418 minutes (270-690 minutes; P = .007), ventilation time of 6 hours (0-26 hours) versus 14 hours (0-278 hours; P = .004), intensive care unit stay of 20 hours (11-70 hours) versus 44 hours (16-336 hours; P=.183), hospital stay of 7 days (4-13 days) versus 8 days (5-21 days; P = .038), and cumulative freedom from angina at 36 months of 93% versus 100% (P = .317).

CONCLUSION

We conclude that technical difficulties during totally endoscopic coronary artery bypass grafting translate into markedly increased operative time, moderately prolonged postoperative ventilation time, and slightly increased hospital stay. Short-term survival and freedom from angina, however, do not seem to be compromised.

Ongoing Procedure Development in Robotically Assisted Totally Endoscopic Coronary Artery Bypass Grafting (TECAB)

BACKGROUND

Totally endoscopic coronary artery bypass grafting (TECAB) using robotics requires stepwise introduction into a heart surgery program. It is the aim of this study to evaluate the state of procedure development after continued application of telemanipulation techniques in the clinical setting. We also sought to assess perioperative and intermediate term clinical results after robotically assisted CABG.

PATIENTS AND METHODS

From June 2001 to March 2005, robotically assisted CABG using the daVinci system was carried out in 107 patients with single and multi-vessel coronary artery disease. The following procedures were performed: robotically assisted endoscopic left internal mammary artery (LIMA) harvesting and completion of the procedure as conventional CABG, MIDCAB, or OPCAB (n = 22), robotically assisted suturing of LIMA-to-LAD anastomoses during conventional CABG (n = 28), TECAB on the arrested heart using remote access perfusion (n = 48), TECAB on the beating heart using an endostabilizer (n = 8), takedown of adhesions (TECAB intended) (n = 1).

RESULTS

Hospital mortality was 0% and cumulative risk adjusted mortality reached 1.6 lives saved versus EuroSCORE predictions. Undesirable surgical events (USE) such as conversion, on table revision, or postoperative revision procedures occurred in 34 out of 107 (32%) patients. Median ventilation time and ICU stay, however, were 11(0-278) hours and 21(11-389) hours, respectively. Cumulative 3 years survival was 100% and freedom from angina at 3 years was 97%.

CONCLUSIONS

We conclude that despite being surgically challenging robotically assisted coronary artery surgery can be implemented with acceptable safety. TECAB procedures have reached a reproducible state. Perioperative mortality after robotically assisted CABG may be lower than predicted. Intermediate term clinical results are very satisfactory.

Totally endoscopic coronary artery bypass graft: initial experience with an additional instrument arm and an advanced camera system

BACKGROUND

Robotically enhanced telemanipulation for totally endoscopic coronary artery bypass does not provide adequate tactile feedback, traction, or countertraction. The exposition of coronary target sites is difficult, the visual field is limited, and the epicardial stabilization may be troublesome. A fourth robotic arm for endothoracic instrumentation has been added to the da Vinci surgical system to facilitate totally endoscopic operations. The stereoendoscope was upgraded with a wide-angle feature.

METHODS

The procedure was performed in five patients. Four of these patients had left internal thoracic artery (LITA) to left anterior descending artery (LAD) grafting on the beating heart and the fifth had sequential bypass grafting (LITA to diagonal branch and LAD) on an arrested heart. The additional effector arm of the da Vinci surgical system was brought into the operative field beneath the operating table and used as a second right arm. The wide-angle view was activated by either the console or the patient side surgeon.

RESULTS

The mean operative, port placement, and anastomotic times for a beating-heart totally endoscopic coronary artery bypass were 195 +/- 58, 25 +/- 10, and 18 +/- 5 min, respectively. All procedures were free of morbidity and mortality, with satisfactory angiographic control. The sequential arterial bypass grafting procedure was fully completed in totally endoscopic technique.

CONCLUSIONS

The additional instrumentation arm and wide-angle visualization are useful technical improvements of the da Vinci surgical system, solving the problem of traction, countertraction, and facilitated exposition of target sites as well as visualization of the surgical field. They provide potential for wider acceptance of totally endoscopic coronary artery bypass grafting in a larger surgical community.

Current status of robotically assisted coronary revascularization

This article reviews the current status of totally endoscopic coronary revascularization using telemanipulation systems for robotic assistance. Current challenges in implementing a robotic surgical program are discussed, and application of the technology in both arrested and beating heart procedures is considered.

Endoscopic localization and assessment of coronary arteries by 13 MHz epicardial ultrasound

BACKGROUND

In totally endoscopic coronary artery bypass grafting the target coronary artery is difficult to locate and assess. We explored the capacity of a high-frequency epicardial ultrasound mini-transducer (Aloka, Tokyo, Japan) to endoscopically locate and assess the left anterior descending (LAD), third obtuse marginal (OM3), and right posterior descending (RDP) coronary arteries.

METHODS

In eight pigs, the LAD, OM3, and RDP were endoscopically exposed. The mini-transducer was manipulated by the "da Vinci" telemanipulation system (Intuitive Surgical, Inc, Mountain View, CA) over the unstabilized and stabilized epicardium to identify the target artery, obtain a scout scan, and both transverse and longitudinal images.

RESULTS

In both unstabilized and stabilized conditions, the LAD and RDP were identified within a median of 29 seconds. In stabilized conditions, assessment was complete in 112 seconds (92 to 205) (median with range) for the LAD and 140 seconds (54 to 197) for the RDP. Stabilization of the OM3 was required for identification (16 [5 to 60]) and assessment (111 [82 to 225]). Overall identification was correct in 23 of 24 arteries. The OM branches and RDP became fully exposed endoscopically with stroke volume (SV) and mean arterial pressure (MAP) remaining at 67% +/- 11% (mean +/- standard error of the mean) and 70% +/- 5% of baseline values, respectively. Scanning itself did not augment the decrease in SV and MAP significantly.

CONCLUSIONS

After proper endoscopic exposure and stabilization, robot-assisted epicardial ultrasound scanning enabled endoscopic identification and assessment of major coronary arteries within a median of 169 seconds per artery. Exposure, stabilization, and scanning were accompanied by an acceptable drop in stroke volume and mean arterial pressure.

Robotics and ergonomics

Industrial robotics have proven the benefit of using an untiring machine to perform precise repetitive tasks in uncomfortable or dangerous for humans environments. Highly skilled surgeons are trained to operate and adapt to difficult conditions. They are even capable of developing intelligent mechanisms to exploit a variety of tactile, visual, and other cues. The robotic systems, however, can enhance the surgeon's capability to perform a wide variety of tasks. They cannot replace the surgeon's problem-solving ability. Instead, they will redefine his role. They will significantly enhance the surgeon's skills and dexterity by providing their complementary capabilities and an ergonomically efficient and more user-friendly working environment.

Robotic cardiac surgery: overview

Most endoscopic procedures are excisional, not reconstructive or microsurgical, mostly because conventional endoscopic instrumentation lacks dexterity due to long, nonarticulated instruments, a fixed pivot point and counterintuitive movement of the instrument tip, and lack of depth perception. Endoscopic approaches to cardiac surgery have not been successful; however, the development of robotic surgical systems has overcome many limitations of endoscopy. Computer-assisted surgery has created a computerized digital interface between the surgeon's hands and surgical instrument tips and enhances surgical ability, thereby enabling endoscopic microsurgery. Recently, robotic systems have allowed cardiac surgeons to perform minimally invasive endoscopic coronary artery bypass grafting (CABG) and valve procedures. This article summarizes the use of robotics in cardiac surgery and discusses its potential in our specialty.

Limitations for manual and telemanipulator-assisted motion tracking—implications for endoscopic beating-heart surgery

BACKGROUND

Surgical performance is limited by human factors. Beating-heart surgery requires full dexterity and motion tracking. Currently techniques for total endoscopic beating-heart bypass grafting using telemanipulation systems are being developed. The aim of this study was to assess the limitations for manual and telemanipulator-assisted motion tracking using the da Vinci telemanipulator system.

METHODS

To simulate beating-heart conditions an endoscopic trainer was developed. Twenty subjects were asked to touch targets manually and with telemanipulator assistance with different patterns of increasing index of difficulty (resting model, unstabilized, and stabilized model with a frequency of 35, 60, and 90 beats per minute). In addition one task was performed using different scaling ratios on a resting model. The times between hits as well as errors were electronically recorded.

RESULTS

There was no significant impact of various frequencies and amplitudes for manual tracking. The average values for the delay (k(m)[ms]) and information-processing (c(m) [ms/bit]) constants for the manual tasks were 201 ms and 86 ms/bit respectively. Both the delay constant (k(t) = 630 ms; p < 0.0005) and the information-processing constant (c(t) = 250 ms/bit; p < 0.0005) were increased for the telemanipulator-assisted tasks at rest. When working on moving targets telemanipulator-assisted tracking required significantly more time and led to more errors. At a frequency of 90 beats per minute telemanipulator-assisted tracking became more difficult.

CONCLUSIONS

Endoscopic beating-heart bypass grafting requires optimal stabilization to avoid inaccuracies due to incomplete motion tracking. At higher frequencies telemanipulator-assisted tracking became more difficult, demonstrating the technical limits of current telemanipulator technology.

Port Placement Planning in Robot-Assisted Coronary Artery Bypass

Properly selected port sites for robot-assisted coronary artery bypass graft (CABG) improve the efficiency and quality of these procedures. In clinical practice, surgeons select port locations using external anatomic landmarks to estimate a patient's internal anatomy. This paper proposes an automated approach to port selection based on a preoperative image of the patient, thus avoiding the need to estimate internal anatomy. Using this image as input, port sites are chosen from a grid of surgeon-approved options by defining a performance measure for each possible port triad. This measure seeks to minimize the weighted squared deviation of the instrument and endoscope angles from their optimal orientations at each internal surgical site. This performance measure proves insensitive to perturbations in both its weighting factors and moderate intraoperative displacements of the patient's internal anatomy. A validation study of this port site selection was performed. cardiac algorithm also Six surgeons dissected model vessels using the port triad selected by this algorithm with performance compared to dissection using a surgeon-selected port triad and a port triad template described by Tabaie et al., 1999. With the algorithm-selected ports, dissection speed increased by up to 43% (p = 0.046) with less overall vessel trauma. Thus, this algorithmic approach to port site selection has important clinical implications for robot-assisted CABG which warrant further investigation.

Telesurgery, telementoring, virtual surgery, and telerobotics

With the advent of laparoscopic surgery, a method characterized by a surgeon's lack of direct contact with the patient's organs and tissue and the availability of magnified video images, it has become possible to incorporate computer and robotic technologies into surgical procedures. Computer technology has the ability to enhance, compress, and transmit video signals and other information over long distances. These technical advances have had a profound effect on surgical procedures and on the surgeons themselves because they are changing the way surgery is taught and learned. This article provides an overview of the most important advances and issues developing from the use of computer and robotic technologies in surgery.

Robotics and coronary artery surgery

Significant progress in cardiac surgery, and specifically the surgical management of coronary artery disease, has been due in large part to enabling technology. Robotic systems have been recently developed and refined for use in cardiac surgery to facilitate, among other procedures, a totally endoscopic approach to coronary artery bypass surgery. These systems enhance precision through endoscopic approaches by specifically addressing the inherent limitations of conventional endoscopic coronary microsurgical instrumentation via computerized, digital interface, telemanipulation technology. With a combined experience of 125 patients, several groups have independently demonstrated the clinical feasibility of totally endoscopic coronary artery bypass with two commercially available robotic telemanipulation systems. Additional enabling technology is needed to overcome the challenges currently limiting development and widespread application of totally endoscopic off-pump multivessel coronary artery bypass surgery.

Transcontinental robot-assisted remote telesurgery: feasibility and potential applications

OBJECTIVE

To show the feasibility of performing surgery across transoceanic distances by using dedicated asynchronous transfer mode (ATM) telecommunication technology.

SUMMARY BACKGROUND DATA

Technical limitations and the issue of time delay for transmission of digitized information across existing telecommunication lines had been a source of concern about the feasibility of performing a complete surgical procedure from remote distances.

METHODS

To verify the feasibility and safety in humans, the authors attempted remote robot-assisted laparoscopic cholecystectomy on a 68-year-old woman with a history of abdominal pain and cholelithiasis. Surgeons were in New York and the patient in Strasbourg. Connections between the sites were done with a high-speed terrestrial network (ATM service).

RESULTS

The operation was carried out successfully in 54 minutes without difficulty or complications. Despite a round-trip distance of more than 14,000 km, the mean time lag for transmission during the procedure was 155 ms. The surgeons perceived the procedure as safe and the overall system as perfectly reliable. The postoperative course was uneventful and the patient returned to normal activities within 2 weeks after surgery.

CONCLUSIONS

Remote robot-assisted surgery appears feasible and safe. Teletransmission of active surgical manipulations has the potential to ensure availability of surgical expertise in remote locations for difficult or rare operations, and to improve surgical training worldwide.

Prospective clinical trial of robotically assisted endoscopic coronary grafting with 1-year follow-up

OBJECTIVE

To follow up in prospective fashion patients with coronary artery anastomoses completed endoscopically with robotic assistance. The robotic system was evaluated for safety and its effectiveness in completing microsurgical coronary anastomoses.

SUMMARY BACKGROUND DATA

Recently there has been an interest in using robotics and computers to enhance the surgeon's ability to perform endoscopic cardiac surgery. This interest has stemmed from the rapid advancement of technology and the desire to make cardiac surgery less invasive. Using traditional endoscopic instruments, it has not been possible to perform coronary surgery.

METHODS

Nineteen patients underwent robotically assisted endoscopic coronary artery bypass grafting of the left internal thoracic artery (LITA) to the left anterior descending artery (LAD). Two robotic instruments and one endoscopic camera were placed through three 5-mm ports. A robotic system was used to construct the LITA-LAD anastomosis. All other required grafts were completed by conventional techniques.

RESULTS

Seventeen LITA-LAD grafts (89%) had adequate intraoperative flow. The mean LITA-LAD graft flow was 38.5 +/- 5 mL/min. At 8 weeks, LITA-LAD grafts were assessed by angiography and showed 100% patency with thrombolysis in myocardial infarction (TIMI) I flow. At a mean follow-up of 17 +/- 4.2 months, all patients were NYHA class I and there were no adverse cardiac events.

CONCLUSIONS

The results from the first prospective clinical trial of robotically assisted endoscopic coronary bypass surgery in the United States showed favorable short-term outcomes with no adverse events. Robotic assistance is an enabling technology allowing the performance of endoscopic coronary anastomoses.