Asian Cardiovasc Thorac Ann 2006;14:109-113
© 2006 Asia Publishing EXchange Ltd
Minimal Access Heart Surgery via Lower Ministernotomy: Experience in 460 Cases
Han-Song Sun, MD,
Wei-Guo Ma, MD,
Jian-Ping Xu, MD,
Li-Zhong Sun, MD,
Feng Lu, MD,
Xiao-Dong Zhu, MD
Department of Cardiovascular Surgery, Fu Wai Hospital, Chinese Academy of Medical Sciences, Beijing, China
For reprint information contact: Han-Song Sun, MD Tel: 86 10 8839 6321 Fax: 86 10 6831 3012 Email: shs1505{at}sina.com, Department of Cardiovascular Surgery, Fu Wai Hospital, 167 Northern Lishi Road, Beijing 100037, China.
 |
ABSTRACT
|
|---|
Minimally invasive cardiac surgery has captured the interest and attention of cardiac surgeons throughout the world. We reviewed our experience of minimal access cardiac operations performed through a lower median ministernotomy. Between January 1997 and August 2003, 100 congenital, 178 valvular, 168 coronary, 12 aneurysmal, and 2 other operations were performed via a 6 to 9 cm lower ministernotomy in 460 consecutive patients. No special instruments were required. Four patients died, and 2 re-operations were necessary. Complications occurred in 28 patients (6.1%). The mean cardiopulmonary bypass time was 88.50 ± 65.16 min, crossclamp time was 55.81 ± 31.89 min, time to extubation was 14.71 ± 29.33 h, and total chest drainage was 7.28 ± 5.07 mL·kg–1. Blood transfusions of 951.42 ± 642.34 mL were needed in 282 patients. Postoperative hospital stay was 11.6 ± 6.0 days. Our experience shows that many types of cardiac operations can be performed through a lower ministernotomy. This technique results in less trauma, quick recovery, and reduces the risk of infection and blood loss. It is a safe and easy procedure that can bring about favorable early outcomes in a wide range of cardiac operations.
|
INTRODUCTION
|
|---|
The traditional full median sternotomy has been the best approach for most cardiac operations since the beginning of the cardiac surgery era in the 1950s. It allows a wide exposure of the heart and the origin of the great vessels, but this quality of exposure is sometimes compromised by "surgical aggressiveness" (postoperative bleeding, wound infection, pain, thoracic wall instability, and an unesthetic scar).1–3 The need to avoid these hazards explains the interest in minimally invasive cardiac procedures that have been growing in popularity over the past decade. Smaller incisions have become an expectation of patients, and cardiac operations in particular are being performed more frequently through alternative or smaller incisions than the traditional full median sternotomy. The ideal minimally invasive incision will permit access to all areas of the heart, require a minimum of specialized equipment, and provide an advantage to the patient of more rapid return to normal activities.4 This article describes the techniques that have been employed at Fu Wai Hospital, Chinese Academy of Medical Sciences, Beijing, which allow cardiac operations via a small but familiar standard incision.
|
PATIENTS AND METHODS
|
|---|
Between January 1997 and August 2003, 460 patients underwent cardiac operations via a lower median ministernotomy in our hospital. The total number of cardiac operations during this period was 23,244. Informed consent was obtained from all patients. There were 254 males and 206 females, with a mean age of 44.5 ± 15.7 years (range, 13 to 77 years, median 47 years). The majority (442, 96.1%) of patients were aged between 14 and 70 years. Nine patients were 
14 years and 9 were 
70 years. The mean body weight was 63.3 ± 12.4 kg (range, 29 to 96 kg). The surgical indications were congenital heart disease in 100 (21.7%), valvular heart disease in 178 (38.7%), ischemic heart disease in 153 (33.3%), ischemic and valvular heart disease in 15 (3.3%), aortic aneurysm in 12 (2.6%), left atrial myxoma in 1 (0.2%) and coronary arteriovenous fistula in 1 (0.2%). Preoperative diagnosis was established in all patients by symptoms and signs together with chest radiographs, electrocardiograms, echocardiography, and computed tomography. The mean cardiothoracic ratio was 0.53 ± 0.08 (range, 0.37 to 0.87).
For the lower median ministernotomy, the patient was placed in the supine position. Standard intubation and hemodynamic monitoring were used, and the surgical field was prepared and draped as for a classic sternotomy. A midline skin incision of 6 to 9 cm in length was made over the sternum, starting from 3 cm below the sternal angle inferiorly and extending slightly beyond the xiphoid process. The skin and subcutaneous tissue were dissected, and a sternal saw was used to split the sternum (manubrium and body) from the xiphoid process to the second intercostal space where the sternum was partially transected by turning the saw rightward. A thoracic retractor was inserted and the pericardial sac was opened from the diaphragm to the aortic reflection superiorly. Retraction stitches were placed on the edges of the pericardial sac and attached tightly to the skin to elevate the heart anteriorly for better exposure. Aortic cannulation was as high as possible on the ascending aorta, and the usual pursestring stitches were placed to accommodate the perfusion cannulas. After establishing cardiopulmonary bypass (CPB), the aorta was occluded with a DeBakey titanium vascular clamp (60°-angled) in an anteroposterior manner, with the posterior blade of the clamp in the transverse sinus. The occlusion clamp was placed as close as possible to the aortic perfusion cannula, providing a substantial length of ascending aorta below the clamp. A standard vent catheter could be introduced through the right superior pulmonary vein or the atrial septum. Different methods of venous cannulation, perfusion of cardioplegia solutions, and myocardial protection were used according to the procedures being performed. No special instruments or cannulas were required in these operations.
In coronary artery surgery, the left edge of the sternum was elevated, and the mammary pedicle dissection was started at the 4th intercostal space. The internal mammary pedicle was developed at the lower half of the sternum. The intact portion of the sternum was elevated anteriorly with a modified sternal retractor (Figure 1
). A lung pad limited the movement of the lung during the harvesting. This allowed the mammary artery pedicle to be developed superiorly to the usual extent of dissection. Table 1 lists the type, number and percentage of procedures performed through the lower median ministernotomy. There were 100 (21.7%) congenital and 178 (38.7%) valvular procedures, including 11 valve repairs. Among the 168 (36.5%) coronary artery procedures, concomitant valve operations were performed in 15 (3.3%) cases. Aortic aneurysm accounted for 2.6% (12) of the whole series.
|
RESULTS
|
|---|
All data are expressed as mean ± standard deviation. Except in the 66 cases of off-pump coronary artery bypass grafting (CABG), the duration of CPB and aortic clamping was 88.50 ± 65.16 min (range, 25 to 1,115; median, 80 min), and 55.81 ± 31.89 min (range, 0 to 164; median, 52.5 min), respectively. The operation time was 205.36 ± 79.81 min (range, 75 to 1,200; median 192.5 min). The mean time to extubation was 14.71 ± 29.33 h (range, 0 to 364; median, 10 h). The mean lengths of intensive care unit stay and hospital stay were 2.73 ± 2.39 days (range, 1 to 28; median, 2 days), and 11.6 ± 6.0 days (range, 1 to 60; median 10 days), respectively. The chest drainage was 461.35 ± 351.65 mL (range, 20 to 3,290 mL) and when calculated by body weight, the mean chest drainage was 7.28 ± 5.07 mL·kg–1. Blood transfusion was needed in 282 patients; blood usage was 951.42 ± 642.34 mL. No re-exploration for bleeding was required. The length of the incision was 6 to 9 cm in all cases.
There were 4 hospital deaths (0.87%). Specifically, the mortality rates for coronary and valve surgery were 0.60% (1/168) and 1.69% (3/178), respectively. One patient suffered low cardiac output syndrome unresponsive to intra-aortic balloon pumping after mitral valve replacement and tricuspid valvuloplasty. He was complicated by left femoral artery embolism and intrapulmonary hemorrhage, and succumbed to ventricular fibrillation on the 12th postoperative day. One patient could not be weaned from CPB (lasting for 1,115 min) after mitral and aortic valve replacement. Intra-aortic balloon pumping proved ineffective, and he died of severe low cardiac output syndrome. The third patient died of cardiac tamponade because of left ventricular rupture 8 h after mitral valve replacement along with tricuspid valvuloplasty. The last death occurred in a patient who developed acute myocardial infarction after CABG due to occluded conduits, which was confirmed by re-operation. He died of intractable circulatory failure although redo CABG was performed in time.
Postoperative complications occurred in 28 patients with an incidence of 6.09%. There were 2 cases of acute myocardial ischemia (0.43%), defined as either the development of new Q waves or an elevation of the MB fraction of creatine kinase along with either elevation of ST segments or onset of new conduction disturbances. One patient suffered recurrent angina, but re-operation was not indicated. The other patient developed acute myocardial infarction because of graft occlusion confirmed by emergency re-operation. Redo CABG was successful and an intra-aortic balloon pump was inserted for temporary circulatory support. One patient suffered hemolysis (0.22%), as evidenced by severe hematuria after mitral valve replacement and tricuspid valvuloplasty. Repeat mitral valve replacement was performed on the 16th postoperative day. Neurocognitive disorders occurred in 4 patients (0.87%) as manifested by conscious disturbance. The reasons included carbon dioxide retention and cerebral infarction. Two tracheotomies (0.43%) and 3 repeat tracheal intubations (0.65%) were needed for hypoxia, neurocognitive disorders or fatal arrhythmias. Two patients (0.43%) had lung infections cured by effective antibiotics. Arrhythmia occurred in 8 patients (1.74%) that necessitated intravenous antiarrhythmic agents or external defibrillation, including ventricular premature beat in 2 cases, ventricular fibrillation in 2, supraventricular tachycardia in 1, and atrial fibrillation in 3. Six patients (1.30%) had skin incision dehiscence that required debridement, and drainage was needed in 3 patients (0.65%) due to skin incision infection. There was no case of sternal dehiscence.
|
DISCUSSION
|
|---|
The past decade has seen a growing emphasis on less invasive surgical procedures. Incisions have become progressively smaller, and minimally invasive techniques for heart operations have grown in popularity, which has been in part stimulated by the recognition of their efficacy in other surgical specialties.5,6 As modern cardiac surgery has improved the prognosis of most types of operations, less invasive approaches and esthetic results have become important issues.1–3 Nevertheless, the definition of "minimally invasive" remains unclear and often is focused on the size and location of incisions. Each option should be considered as a trade-off between the exposure provided, the ease and speed of the operation, and postoperative patient recovery.7
The small lower sternal incision used in this series gave excellent exposure of the base of the heart. No specially adapted instruments were used. In our experience, the hospital mortality and morbidity, duration of operation, CPB, and aortic crossclamping, and lengths of intensive care unit and hospital stay were comparable to those reported for procedures with the conventional sternotomy approach. Complications that accompany the lower median ministernotomy approach are similar to those in standard cardiac operations. No specific complications can be ascribed to the smaller incision or to diminished exposure of the operative field.
Thus, it appears that the lower median ministernotomy approach is safe and permits the full spectrum of procedures, including correction or repair of congenital heart defects such as ventricular septal defect, atrial septal defect, patent ductus arteriosus, and tetralogy of Fallot, as well as single or double valve replacement or repair combined with tricuspid valvuloplasty. It is also indicated in redo valve procedures if the previous incision was other than a median sternotomy. For off-pump CABG, this incision is used for bypass of the left anterior descending artery with its diagonal branches, right coronary and posterior descending artery. For conventional CABG, grafting of the ramus medianus and marginal branches of the circumflex artery can be performed in association with valve replacement or repair, and repair of left ventricular aneurysm. In aortic surgery, this incision is chiefly used in aneurysm operations involving the aortic root.
There are several potential and practical advantages to the lower median ministernotomy approach. The 6 to 9 cm long skin incision is much smaller than the traditional midline sternotomy incision. It reduces the pain from over-stretching of the ribs and thoracic ligaments, and the wound is less painful than the conventional full sternotomy. The postoperative chest wall function, and therefore total lung compliance are greatly preserved, particularly in elderly patients, while providing adequate and familiar exposure of the heart and great vessels.8 The operative field can be viewed directly without video assistance or specialized instrumentation. Another important advantage of this technique is the easy and rapid conversion to a standard sternotomy should technical problems be encountered or if exposure is not adequate, in contrast to paramedian, transverse sternal, or intercostal incisions, which are more difficult to extend.4 This bone-limited median sternotomy appears to be associated with accelerated healing, is more stable, and less painful. There is also less potential for wound infection and blood loss. Patient recovery is accelerated, allowing a shorter intensive care unit stay and earlier hospital discharge, with an overall reduction in cost. Re-operation should be less difficult. Last, but not least important, is the cosmetically appealing skin incision. Many works have reported the potential for psychological disturbance, especially in young female patients, when an unsightly scar is present in the middle of the thorax. Essentially, this approach gives a better esthetic result due to the limited extent of the scar.
Wound closure after a ministernotomy requires modification of the standard sternal fixation technique because of the transection at the second intercostal space. Although there is potential for sternal nonunion at this point, no patient had sternal dehiscence requiring re-operation for sternal fixation. Apparently, the intact upper sternum imparts some reliable stability to the closure and provides a solid base for eventual sternal union.4 Nevertheless, caution should be taken with a lower median ministernotomy in high-risk patients, such as those who have had a previous median sternotomy, or patients with severe respiratory and cardiac insufficiency (a left ventricular ejection fraction 30% or a left ventricular end-diastolic dimension 75 mm). In off-pump CABG, grafting of the left posterior ventricular and obtuse marginal branches still remains a contraindication.
It was concluded from this experience that the lower median ministernotomy provides beneficial results in a wide range of cardiac operations. Standard instruments and CPB techniques are used, and the operative exposure is familiar. The sternal closure is secure and less painful than the traditional sternotomy, accelerating postoperative recovery. Congenital defect repair, complete coronary revascularization, aneurysmal, and essentially all valve procedures can be performed via the ministernotomy.
|
REFERENCES
|
|---|
- Hartz RS. Minimally invasive heart surgery. Executive Committee of the Council on Cardio-Thoracic and Vascular Surgery. Circulation 1996;94:2669–70.[Free Full Text]
- Lytle BW. Minimally invasive cardiac surgery. J Thorac Cardiovasc Surg 1996;111:554–5.[Medline]
- Gundry SR, Shattuck OH, Razzouk AJ, del Rio MJ, Sardari FF, Bailey LL. Facile minimally invasive cardiac surgery via ministernotomy. Ann Thorac Surg 1998;65:1100–4.[Abstract/Free Full Text]
- Doty DB, Flores JH, Doty JR. Cardiac valve operations using a partial sternotomy (lower half) technique. J Card Surg 2000;15:35–42.[Medline]
- Cooley DA. Minimally invasive valve surgery versus the conventional approach. Ann Thorac Surg 1998;66:1101–5.[Abstract/Free Full Text]
- Soper NJ, Brunt LM, Kerbl K. Laparoscopic general surgery. N Engl J Med 1994;330:409–19.[Free Full Text]
- Massetti M, Babatasi G, Lotti A, Bhoyroo S, Le Page O, Khayat A. Less invasive cardiac operations through a median sternotomy: 100 consecutive cases. Ann Thorac Surg 1998;66:1050–4.[Abstract/Free Full Text]
- LoCicero J 3rd, McCann B, Massad M, Joob AW. Prolonged ventilatory support after open-heart surgery. Crit Care Med 1992;20:990–2.[Medline]
TOP
ABSTRACT
INTRODUCTION
