Less invasive methods for mitral valve surgery have

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1 Totally Endoscopic Mitral Valve Repair Using a Robotic-Controlled Atrial Retractor J. Michael Smith, MD, Hubert Stein, BS, BME, Amy M. Engel, MA, Sarah McDonough, and Lindsey Lonneman Department of Surgery, Good Samaritan Hospital, Cardiac, Vascular, and Thoracic Surgeons Inc, Cincinnati, Ohio; Intuitive Surgical Inc, Sunnyvale, California; E. Kenneth Hatton, MD, Institute for Research and Education, Cincinnati, Ohio Purpose. Our aim was to assess the feasibility of totally endoscopic robotic mitral valve surgery using a novel atrial retractor manipulated by a fourth arm da Vinci surgical system (Intuitive Surgical Inc, Sunnyvale, CA). Description. Eighteen patients with mitral valve disease underwent totally endoscopic mitral valve surgery using the retractor. It was inserted in the second or third intercostal space just lateral to the sternum, and it was manipulated at the robotic console for dynamic exposure of the valve structures. Evaluation. Mitral valve repair procedures were feasible in all patients with the robotic-controlled atrial retractor providing superior exposure of the mitral valve anatomy. The time until satisfactory exposure of the mitral valve was noticeably decreased with the robotic retractor. All patients were discharged home in sinus rhythm and transesophageal echocardiography revealed competent mitral valves. Conclusions. The EndoWrist atrial retractor (Intuitive Surgical Inc) facilitated complex totally endoscopic mitral valve surgery, including concomitant procedures, regardless of pathology with excellent clinical outcomes. (Ann Thorac Surg 2007;84:633 7) 2007 by The Society of Thoracic Surgeons Less invasive methods for mitral valve surgery have been developed in the past decade, with several groups reporting excellent outcomes with an endoscopic approach [1, 2]. One reason adoption has not been widespread and mitral valve repair rates have been compromised with a nonrobotic thoracotomy approach is because of the technical difficulty of gaining adequate exposure of the entire mitral valve. Static mechanical retractors currently used for endoscopic mitral valve surgery have limited capabilities and often only marginally expose the valve structures. Endoscopic robotic mitral valve surgery with the da- Vinci surgical system (Intuitive Surgical Inc, Sunnyvale, CA) has facilitated operations on more complex pathologies [3 7], but even with robotic assistance, placing and securing a static mechanical retractor in an endoscopic fashion has remained a technical challenge (see Table 1). The recent introduction of a robotically controlled EndoWrist atrial retractor (Intuitive Surgical Inc, Sunnyvale, CA) was designed to overcome this current limitation (Table 1). We report on the use of this novel robotic atrial retractor that allows dynamic atrial retraction and its feasibility to facilitate totally endoscopic mitral valve surgery. Technology Atrial Retractor The atrial retractor instrument is based on EndoWrist technology and is controlled by the davinci surgical system (Fig 1). EndoWrist technology and the davinci surgical system are described in Murphy and colleagues [4] and Guthart and Salisbury [8]. The instrument provides 6 of freedom and is equipped with two 8 mm 45 mm blunt blades that are curved at the distal tip to avoid trauma to the heart and prevent slipping of septum and atrial tissue. The opening angle between the blades can be controlled by the surgeon s grip action on the console. The maximum opening of 60 provides a tissue support area that is similar to a 45 mm 35 mm blade from a static mechanical retractor. For different applications during the procedure, the angle and plane of exposure can be immediately changed. Accepted for publication March 9, Address correspondence to Dr Smith, c/o Amy Engel, Hatton Institute, Good Samaritan Hospital, 375 Dixmyth Ave, Cincinnati, OH 45220; amy_engel@trihealth.com. Dr Smith and Mr Stein disclose a financial relationship with Intuitive Surgical by The Society of Thoracic Surgeons /07/$32.00 Published by Elsevier Inc doi: /j.athoracsur

2 634 SMITH ET AL Ann Thorac Surg VALVE REPAIR WITH ROBOTIC ATRIAL RETRACTOR 2007;84:633 7 Table 1. Limitations of Static Manual Retractor Compared With EndoWrist Atrial Retractor Feature Static Manual Retractor EndoWrist Atrial Retractor a Fulcrum effect Reversed motion, compromising valve exposure Not in effect due to robotic control and EndoWrist technology Exposure plane Flat (90 to handle-rod) Multiple angles and exposure planes possible Retractor manipulation By patient-side assistant, readjustments By console surgeon, fully independent control cumbersome and disrupting procedure Mechanical design Multiple pieces, endoscopic assembly necessary One-piece design without assembly Retractor profile Exposure type Rectangular blade (sizes differ) with tall rim/edge obstructing anterior annulus Static; combination of holding arm and retractor does not allow for easy adjustments of the blade in the atrium Low profile with 8 45 mm blades; visualization of entire mitral valve structures possible Dynamic; adaptable to surgical needs in real time Thoracotomy size 3 5 cm depending on blade size Atrial retractor inserted through 8 mm port, thoracotomy only depending on valve sizer (commonly cm) Subvalvular exposure Extremely limited Possible; down to the papillary muscle Ease of use Unfavorable Favorable a Robotically controlled (EndoWrist atrial retractor [Intuitive Surgical Inc, Sunnyvale, CA]). Technique Patients Between December 2005 and February 2006, 18 consecutive patients with mitral valve regurgitation underwent endoscopic mitral valve surgery with the davinci surgical system and the robotic retractor. One of the 18 patients was scheduled for valve replacement due to rheumatic disease of the mitral valve. Institutional Review Board approval was obtained for all patients prior to surgery. Patient characteristics are given in Table 2. Surgical The surgical technique has been described in detail elsewhere [3]. The port set-up in this series was modified to allow application of the retractor. A 12-mm port was created for the camera on the mid-clavicle line in the Fig 1. EndoWrist atrial retractor (Intuitive Surgical Inc, Sunnyvale, CA) instrument provides 6 of freedom. The two 8 mm 45 mm blunt blades are curved at the distal tip to avoid trauma to the heart and prevent slipping of septum and atrial tissues. fourth intercostal space (ICS). The 1.5 to 2 cm working port was made 2 cm posterior to the camera port in the same ICS and was retained open with a flexible 15-mm Thoracoport (Ethicon Inc, New Brunswick, NJ). The right robotic arm port was in the fifth or sixth ICS on the anterior axillary line; the left robotic arm port was in the third ICS, 2 cm medial to the anterior axillary line. A third robotic arm port for the retractor was placed in the third ICS, 2 cm lateral to the sternum (Fig 2). Care has to be Table 2. Patient Characteristics Number of patients 18 Gender 14 (77.8%) male 4 (22.2%) female Age (yrs) (range, 30 76) Atrial fibrillation 3 (16.7%) New York Heart Association functional class I 0 (0%) II 1 (5.6%) III 10 (55.6%) IV 7 (38.9%) Ejection fraction (%) (range, 30 50) Smoking history 8 (44.4%) Hypertension history 6 (33.3%) Chronic obstructive pulmonary 4 (22.2%) disorder Diabetes 1 (5.6%) Dialysis dependent end-stage 1 (5.6%) renal disease Valve cause Degenerative 14 (77.7%) Rheumatic 1 (5.6%) Functional 1 (5.6%) Congenital 2 (11.1%), 1 Marfan syndrome, 1 Ehlers-Danlos syndrome

3 Ann Thorac Surg SMITH ET AL 2007;84:633 7 VALVE REPAIR WITH ROBOTIC ATRIAL RETRACTOR 635 Fig 2. Robotic arm positioning and port placement. (a) Overview of robotic arm set up. Green arm holding robotic atrial retractor. Red arm holding left robotic instrument, yellow arm (covered by surgeon) holding right robotic instrument. (b) Close-up view of ports from patient receiving valve replacement (larger rigid port for thoracotomy used to pass replacement valve). taken not to injure the right internal mammary artery on introduction of the retractor cannula. After a 3 to 4 cm atriotomy was created, the atrial retractor was manipulated into the left atrium. Manipulation of the retractor was possible through switching controls of the robotic arms by the console surgeon with a foot pedal. Once satisfactory exposure of the mitral valve structures have been achieved, the console surgeon switches back to the main left robotic instrument arm locking the retractor in position and gaining control back of both operating instruments. Depending on the visualization needs per applied valve repair technique, the console surgeon switches back to the robotic arm holding the atrial retractor, dynamically exposing the structure of the mitral valve, which is most important during that procedure step (Fig 3). Table 3 presents the variety of valve repair techniques that were performed. Cosgrove bands (Edwards Lifesciences, Irvine, CA) ranging from sizes 26 to 38 (mean size, ) were used in 16 patients. One patient with functional mitral regurgitation received a Geoform Ring (Edwards Inc, Irvine, CA). To secure the annuloplasty device, either a V100 U-Clip (Medtronic Inc, Minneapolis, MN) was used as described by Reade and colleagues [9] or sutures (2-0 Ethibond [Ethicon Inc]) were used. Fig 3. Exposure of mitral valve with robotic-controlled atrial retractor. (a, b) Hooking the blade tips into the anterior leaflet exposes the papillary muscle head and allows easy placement of neochordae. (c) Unobstructed exposure of the anterior annulus for anterior leaflet repair. (d) Excellent visualization of the right trigone facilitating stitch placement for the annuloplasty band.

4 636 SMITH ET AL Ann Thorac Surg VALVE REPAIR WITH ROBOTIC ATRIAL RETRACTOR 2007;84:633 7 Table 3. Performed Mitral Valve Repair Techniques Mitral valve repair 17 (94.4%) Annuloplasty alone 1 (5.6%) Leaflet repair annuloplasty 15 (83.3%) Leaflet repair alone 1 (5.6%) Mitral valve replacement 1 (5.6%) Concomitant robotic cardiac procedure Tricuspid valve repair cryoablation 1 (5.6%) Cryoablation 2 (11.1%) Atrial septal defect closure 1 (5.6%) In the 3 patients that underwent concomitant cryoablation, a Surgifrost XL7 (CryoCath Inc, Montreal, Quebec, Canada) was used. The pulmonary veins were encircled and an annular connecting lesion to the mitral annulus was performed. To provide good tissue contact to the cryoprobe, the atrial retractor was used to stretch part of the left atrium by adjusting the opening angle of the grips. For closure of the left atrial appendage with a double layer suture line, the atrial retractor was moved superiorly to expose the opening of the appendage. In the 1 patient with the concomitant tricuspid valve repair, the venae cavae were snared and the right atrium was opened after closure of the left atriotomy. The retractor exposed the tricuspid valve and a size 30 Cosgrove band (Edwards Inc, Irvine CA) was placed using the V-100 U-Clip (Medtronic Inc). The atriotomy was closed and a standard removal of air was performed. Valve analysis was performed in all patients with transesophageal echocardiogram postoperatively. The mitral valve replacement patient was due to rheumatic disease of the mitral valve and was elected for a bioprosthetic valve (Biocor, St. Jude Medical Inc, St. Paul, MN), and suturing was performed using a standard endoscopic technique with robotic assistance. Clinical Experience The robotic-controlled atrial retractor provided safe and stable exposure of the mitral valve anatomy making the performance of the procedures feasible in all patients. Table 4 summarizes intraoperative and postoperative data. There were no procedure-related complications, deaths or other complications secondary to femoral perfusion. Intraoperative transesophageal echocardiogram revealed excellent repairs in the 17 patients scheduled for valve repairs and a normally functioning valve in 1 patient that received the bioprosthetic valve. All patients who underwent cardiac tissue ablation were in sinus rhythm and remained there at 3 months postoperatively. New onset of atrial fibrillation occurred in 3 patients (16.7%) postoperatively. Two patients experienced a hospital stay greater than 10 days. One patient who underwent mitral valve replacement, tricuspid valve repair, and an atrial ablation procedure required careful management of postoperative rhythm until it stabilized. The other patient with a long hospital stay was on chronic hemodialysis and in class IV heart failure, and also required a prolonged postoperative stay for medical management of end-stage renal disease. Both made successful recoveries. We did not experience a significant learning curve with the robotic atrial retractor. The time from introduction of the atrial retractor until satisfactory exposure of the mitral valve was achieved was noticeably decreased compared with the times in our prior multicenter series using standard static mechanical retractors [4]. Cross-clamp and bypass times were reduced in the range of 10 minutes at conclusion of these initial 18 cases (cardiopulmonary bypass, minutes vs minutes; aortic occlusion, 92.7 minutes vs minutes; data from multicenter study [4]). Now these times are reduced by approximately 20 minutes. Comment This report describes our initial experience using a robotic-controlled atrial retractor designed specifically to enhance endoscopic mitral valve surgery. Mitral valve distortion was found to be minimized with the robotic atrial retractor due to the fact that there was not a thick lip pushing into the anterior annulus as with standard manual retractors. This also allowed for effective intraoperative valve assessment by the visual saline test due to maintenance of atrial geometry. Exposure of the left and right fibrous trigone was enhanced by adjustment of the retractor angle making stitch placement for annuloplasty bands and rings easier in those valve areas. The angle of the diverging blades could be adapted to the surgical needs, and by hooking the blade tips into the anterior leaflet, the papillary muscles were exposed for easy placement of neochordae with a 4-0 Gore-Tex suture (W.L. Gore & Assoc, Flagstaff, AZ). The low profile of the retractor blades also minimized aortic valve distortion, resulting in more efficient antegrade cardioplegia delivery and reduced air entry in the aortic root. The unobstructed exposure of the anterior annulus has facilitated more complex anterior leaflet repairs and made sizing of the valve easier compared with standard manual retractors. The closure of the left atriotomy was facilitated because the retractor could be used to support the anterior edge of the atrial incision freeing up the left and right robotic instruments for performing a running suture line. Other exposure possibilities with the dynamic retractor include atrial septum for atrial septal defect and a patent foramen ovale closure, tricuspid Table 4. Intraoperative and Postoperative Data Intraoperative data Cardiopulmonary bypass (range, ) (mins) Aortic occlusion (mins) (range, ) Postoperative data Intensive care unit (hrs) (range, ; median, 23.5) Length of hospital stay (days) (range, 3 14; median, 5)

5 Ann Thorac Surg SMITH ET AL 2007;84:633 7 VALVE REPAIR WITH ROBOTIC ATRIAL RETRACTOR 637 valve exposure, and atrial exposure for performing surgical ablation. Besides these surgical advantages provided by the device, there are additionally some ease of use benefits for the surgeon and his team. The operating console surgeon regains more control of the surgery by being able to self-assist and have full control of the mitral valve exposure. The one-piece design of the retractor makes it readily available once introduced in the port, because there is no assembly necessary. This obsoletes the cumbersome endoscopic assembly, placement, locking, and securing a static manual retractor in the holding arm for the patient side surgeon in the sometimes constrained workspace. In this series we used the standard davinci surgical system, which due to some mechanical specifics of the robotic arm joints allows only placement of the fourth instrument arm to the left side of the camera coming over the patient s head. This dictates the port location for the robotic atrial retractor to be in the parasternal area (second and third ICS), which in women can lead to potential penetration of breast tissue. This could be avoided by performing the skin incision for the atrial retractor port as lateral as possible and then moving the skin medially during insertion of the cannula. We recommend that when plastic Steri-Drapes (3M, St. Paul, MN) are being applied to women or obese males, the drape part over the breast should be cut out to allow manipulation of the breast tissue possible. With the recent introduction of the davinci S model, which features a different mechanical attachment of the fourth robotic arm to the patient side cart, it is now possible to apply the atrial retractor from the right side of the camera arm in the intercostal space below the camera port (fifth and sixth ICS). This improves cosmesis, and avoids penetration of breast tissue and potential damage to the right internal mammary artery. Even though we have not seen any major collisions between the individual robotic arms or with the patients head and endotracheal tube in our series with the standard da Vinci system, the smaller profile of the da Vinci S robotic arms also help to avoid major collisions between the arms and with the patient s external anatomy. We believe the use of the robotic-controlled atrial retractor also provides some significant outcome benefits for the patient. The dynamic atrial retraction capability allows the performance of complex reconstructions of the mitral valve that otherwise might have been rendered a replacement. Avoiding the distortion of the aortic valve means better cardiac protection for the patient, and shortening of cross-clamp and bypass time might have a positive effect on postoperative recovery. Historically the width of the rigid manual retractor blade determined the size of the thoracotomy incision for assistance. The fact that we were able to reduce the thoracotomy incision to 1.5 cm in our series renders this approach a total endoscopic surgery with added benefits for the patient. In conclusion, the robotic atrial retractor has provided superior exposure of the mitral valve anatomy allowing performance of totally endoscopic mitral valve repairs on a variety of complex pathologies including concomitant procedures. This may drive further adoption of robotic endoscopic surgery on mitral valves in selected centers, and further increase the percentage of valves that can be repaired as compared with the current standard [7]. Disclosures and Freedom of Investigation No funds were used to perform this study. The DaVinci Robot (Intuitive Surgical, Sunnyvale, CA) with atrial retractor is owned by Good Samaritan Hospital. The tested technology was not purchased, borrowed, or donated to the study. The authors had full control of the design of the study, methods used, outcome measurements, analysis of data, and production of the written report. References 1. Casselman FP, Van Slycke S, Dom H, Lambrechts DL, Vermeulen Y, Vanermen H. Endoscopic mitral valve repair: feasible, reproducible, and durable. J Thorac Cardiovasc Surg 2003;125: Mohr FW, Falk V, Diegeler A, Walther T, Van Son JA, Autschbach R. Minimally invasive port-access mitral valve surgery. J Thorac Cardiovasc Surg 1998;115: Murphy DA, Miller JS, Snyder AB. Lateral endoscopic approach to the mitral valve using robotic instrumentation. J Thorac Cardiovasc Surg 2007;133: Murphy D, Smith JM, Siwek L, et al. Multicenter mitral valve study: a lateral approach using the davinci Surgical System. Abstract presented at ISMICS Nifong LW, Chu VF, Bailey BM, et al. Robotic mitral valve repair: experience with the da Vinci system. Ann Thorac Surg 2003;75: Mohr FW, Falk V, Diegeler A, et al. Computer-enhanced robotic cardiac surgery: experience in 148 patients. J Thorac Cardiovasc Surg 2001;121: Nifong LW, Chu VF, Bailey BM, et al. Robotic mitral valve repair: experience with the da Vinci system. Ann Thorac Surg 2003;75: Nifong LW, Chitwood WR, Pappas PS, et al. Robotic mitral valve surgery: a United States multicenter trial. J Thorac Cardiovasc Surg 2005;129: ICRA proceedings: IEEE International Conference on Robotics and Automations: May 21 26, 2001, Seoul, Korea. Piscataway, NJ: IEEE Publications; Reade CC, Bower CE, Maziarz DM, et al. Sutureless robotassisted mitral valve repair: an animal model. Heart Surg Forum 2003:6: Disclaimer The Society of Thoracic Surgeons, the Southern Thoracic Surgical Association, and The Annals of Thoracic Surgery neither endorse nor discourage use of the new technology described in this article.