Due to the rising demand for minimally invasive surgery from patients, minimally invasive mitral valve surgery techniques continue to evolve and are becoming an available alternative to median sternotomy mitral valve surgery. Since Navia and Cosgrove and Cohn first performed minimally invasive mitral valve surgery [8, 9], there have been four main minimally invasive approaches. The approaches include the following: lower hemi-sternotomy, direct-vision right minithoracotomy, endoscopic right minithoracotomy, and robotic-assisted right minithoracotomy.
Lower hemi-sternotomy is an option for minimally invasive mitral valve surgery (MIMVS) [10]. The main advantage of this approach is the ability to directly cannulate and cross-clamp the aorta. In contrast, a direct-vision right minithoracotomy approach is an attractive option for MIMVS because it causes less surgical trauma compared to sternotomy [11]. Other advantages include “straight-on” visualization of the mitral valve, decreased blood loss, lower incidence of significant wound infections, and improved cosmesis [4, 12,13,14,15,16]. In this way, the primary incision is placed at the level of the hilum, usually in the fourth intercostal space, starting at the midclavicular line and extending laterally to the anterior axillary line. The incision should be large enough to allow adequate light to reach the mitral valve. A head lamp may be useful with this technique. A total of approximately 6.0 cm of anterior lateral sub-mammary skin incision is required, and a rib retractor is required at the fourth intercostal space, which can cause severe postoperative pain and may result in rib fracture or intercostal vascular/neural injury. And with this approach, the visualization and lighting of subvalvular apparatus is often cumbersome.
To avoid these potential risks, totally endoscopic surgery can be performed using a 2D thoracoscope without rib spread. Minimally invasive totally endoscopic mitral valve surgery has become increasingly accepted as the norm. The totally endoscopic surgery we perform represents the smallest surgical access available, with no disruption to the sternum and ribs, limited only by the size of the prosthesis and soft tissue retractor. Establishment of extracorporeal circulation only through the femoral artery and vein with a single two-stage femoral venous cannula and an artery cannula. Perform an aesthetically pleasing right minithoracotomy. A lengthened cardioplegia perfusion cannula and transthoracic aortic clamp were introduced.
We have made appropriate improvements over the currently widely used minimally invasive procedures. The use of the single two-stage cannula has many advantages. It avoids the need for insertion of a right internal jugular vein cannula, which can lead to complications such as bleeding, hematoma, carotid artery injury and pneumothorax. In addition, the time required for preoperative preparation of the patient is greatly reduced because jugular vein cannulation is avoided. Although some may argue that air may be entrained in the venous cannula when the right atrium is open, this can be safely avoided if the two perforated segments are positioned correctly. Another issue may be due to the non-perforated section of the cannula crossing the right atrium, which may limit exposure of the tricuspid valve. However, as shown in Fig. 2, the non-perforated segment of the cannula is located at the septum and does not obstruct the valve view. In conclusion, the single two stage cannula can be safely used during surgery in the right atrium, and it allows the pump to function properly, either when the left atrium is retracted during mitral valve surgery or when the right atrium is opened during tricuspid valve surgery. In fact, it represents our preferred method of venous return during totally endoscopic surgery.
This approach provides the highest level of cosmetic results and minimizes discomfort. Casselman et al. reported that 93.5% of patients with non-rib-spreading surgery experienced little or no surgery-related pain with excellent cosmetic results [17].
1998, with the introduction of the da Vinci Surgical System, a robotic remotely operated surgical system with 3D cameras, Carpentier performs first successful robotic heart surgery [18]. However, robotic surgery has not been widely used for various reasons. First the robotic arm still needs to make two or more ports in the chest. Secondly, the main drawback of this remotely operated system is the lack of tactile feedback. Thus, the surgeon relies solely on “visual feedback” during the procedure. In addition, the high price of robotic systems, the use of a limited number of robotic instruments, and the need for two surgeons, a console surgeon and a bedside surgeon, greatly drains medical manpower and patient financial resources.
Therefore, a totally endoscopic mitral valve surgery without robotic assistance may be a reasonable option. A meta-analysis by Modi et al. identified 10 papers published between 1998 and 2005 that were suitable for analysis. The study included 1358 minimally invasive patients and 1469 sternotomy patients. No difference in mortality, stroke, reoperation bleeding, new-onset atrial fibrillation, ICU hospitalization or length of stay despite longer cross-clamp and extracorporeal circulation times in the minimally invasive treatment group [5]. Galloway of New York University reported the longest results to date of minimally invasive mitral valve surgery. Between 1996 and 2008, they performed 1071 minimally invasive mitral valve repair and compared their results with 1601 routine procedures. They reported a perioperative mortality rate of 1.3% in both groups of patients with isolated mitral valve repair, and no difference in major adverse events. The long-term outcome is equivalent to median sternotomy [19]. As one of the consistent findings of various case series over the last decade, it is clear that MIMVS has more operative time (extracorporeal circulation and cross-clamp time) than conventional surgery. Of all the potential benefits of MIMVS, pain relief and a faster return to normal activity were the most consistent findings.
In this study, the mortality rate was 0.53%, which is close to the results reported in the appellate literature, and in addition there was no significant increase in the incidence of serious complications. Therefore, in terms of post-operative mortality and serious complications, the short-term outcomes of totally endoscopic mitral valve surgery in our center are very impressive.
Totally endoscopic surgery for mitral valve disease is technically challenging and its use is currently limited to a small number of experienced surgeons, as it requires surgeons to overcome a lengthy learning curve [20, 21]. Prior to the start of this study, the surgical group had performed multiple hemisternotomy, direct-vision right minithoracotomy cardiac surgery as well as more than 20 totally endoscopic cardiac surgeries, had already gone through the learning curve. This study is representative in the local area.
This study has some limitations owing to retrospective single-institution small-volume observational study design without a control group. Only one surgeon performed the procedures; therefore, inter-operator differences could not be studied.