Ventricular septal defect is one of the most common congenital cardiac defects [1, 2]. Although the transcatheter techniques have been widely used and performed and delivered promising early and midterm results in recent years, the X-ray exposure and potential vascular injury limited the promotion of this approach [3,4,5].And the median sternotomy approach was limited by its visible mid-sternotomy scar, which should be taken into consideration. Surgeons then developed other approaches to reduce the invasiveness of complete median sternotomy and pursue better cosmetic results, especially in children, teenager and female patients . These alternatives included lower mini-sternotomy incision [7, 8], right submammary incision [9, 10], right posterolateral thoracotomy incision  and right vertical infra-axillary incision [12,13,14].
In our institution, we applied right submammary thoracotomy and right vertical infra-axillary thoracotomy in VSD repair. The advantages of the right submammary thoracotomy and right vertical infra-axillary thoracotomy have been previously described. These two thoracotomies are similar to median sternotomy in having enough exposure, no need for special instrument, no difficulty in CPB establishment, and no increased medical cost in most reports. And their advantages have been described, such as faster recovery and better cosmetic results. However, technical complexity including satisfactory exposure, invisible site and the length of incision remained the focus of exploration. As no comparative study has been conducted among right submammary thoracotomy, right vertical infra-axillary thoracotomy and median sternotomy, our study aims to compare these three approaches in repairing VSD under CPB.
Compared with group A, there was no significant difference in CPB time, aortic cross-clap time or operative time in group B and C. We contributed these to those right submammary thoracotomy and right vertical infra-axillary thoracotomy could provide enough good exposure of the inferior vena cava and the ascending aorta without increasing the technical difficulty. However, according to our experience, it’s difficult to setup CPB in female patients with large breast and in patients with a BMI > 28 kg/m  in group B and C. The chest incision in these two groups were also significantly shorter than the median sternotomy group. Meanwhile, there was no need for sternum split or wire fixation, which may lead to negative post-operative X-ray chest examination. But the incidence rates of postoperative pneumothorax and subcutaneous emphysema were significantly higher in group B and C. With strengthened operative technique and management, however, such complications can be well controlled. The surgical success rate of VSD repair via right submammary thoracotomy and right vertical infra-axillary thoracotomy were similar to median sternotomy in this study, which means all the three methods can achieve satisfactory clinical results. Based on these findings, we recommend that right submammary thoracotomy and right vertical infra-axillary thoracotomy be used as effective and safe alternatives in VSD surgical repair.
Cosmetic results should be taken into consideration in such operations, which include incision length, visible or invisible and whether this incision causes thoracic deformity. We found that the incidence of thoracic deformity was higher in median sternotomy group, although 7 patients suffered from pectus carinatum or funnel chest. No significant progress was found in the follow-up period. Close medical observation were given to these 7 patients without any other intervention. In most medical centers, the right submammary thoracotomy was made through the fourth or fifth intercostal space. Compared to the median sternotomy group, the incision caused can’t be seen from the collar, which may be more acceptable to women patients. However, this incision may dissect the breast tissue and result in asymmetrical development and a decrease in sensitivity of the nipple [15, 16]. We contributed these side effects to the difference in incision choice in our institution, where the incision was in the fourth intercostal space for children. In addition, we also obey the rule that the incision should be at least 1.5 cm away from the mammary areola in patients with undeveloped breasts . For female patients the incision was in the submammary groove so that when the operation via the incision would be covered by breast. In addition, during the procedure, we did our best to preserve the right internal mammary vessels.
In our institution, we also repaired VSD via right vertical infra-axillary thoracotomy. Wang et al. reported 274 patients with ventricular septal defects went through repair via a minimal right vertical infra-axillary thoracotomy . In their study there were no deaths or complications from the infection of incisional wound and arrhythmia, and no significant differences in CPB time or postoperative ventilator time. However, the length of incision, postoperative volume drainage and ICU stay, minimal right vertical infra-axillary thoracotomy was significantly shorter than median sternotomy. These results were consistent with the results of our study. First, unlike some other new technology, this incision didn’t require special instruments and most part of the procedure is similar to conventional surgical repair, which means no increase in hospital cost and short learning cure for experienced surgeons. Second, it could provide enough surgical field. Based on these two reasons, the CPB time and the aortic clamping time of this procedure were also similar to those of median sternotomy. And we also found that the hospital stay and the time needed to recover to normal activities in the right vertical infra-axillary thoracotomy group were superior to those of the median sternotomy group, which also suggested faster recovery. Although in most patients this procedure didn’t increase the technical difficulty, it’s still difficult, even for experienced surgeons, to close subarterial VSDs through such procedure. In repairing such kind of VSD, we preferred the right submammary thoracotomy to right vertical infra-axillary thoracotomy, which also provide enough surgical field if placing a wet sponge under pericardial cavity beneath the heart.
For female patients with developed breast, if we chose right submammary thoracotomy, the incision would be covered by breast. However, when operating on children, right vertical infra-axillary thoracotomy may be a better choice. The reasons are listed below: First, this short incision is located under the armpit, which makes it almost invisible; Second, the incision of right submammary thoracotomy never surpasses the preaxillary line and thus will not cause dysplasia. Finally, the incision site is in the chest wall and far from the costochondral junction. Thus, it does not interfere with the development of the chest wall.
The incidence of arrhythmia was similar in all groups. According to previous report, surgical approach (right atrium or right ventricle) did not influence the arrhythmia rate [18, 19], which was the reason why we didn’t conduct subgroup analysis of arrhythmia. According to above-mentioned comparisons, we could conclude that right submammary thoracotomy and right vertical infra-axillary thoracotomy are both safer and more efficient approaches for VSD closure than median sternotomy. We then further compared right submammary thoracotomy and right vertical infra-axillary thoracotomy. We found that there weren’t significant differences in procedure success rate, operation time, ICU stay, postoperative hospital stay or volume of transfusion in these two groups. And the rate of complications were also similar in right submammary thoracotomy and right vertical infra-axillary thoracotomy.
This study was a retrospective study and was limited by the number of cases and the fact that it was done in a single center. Prospective randomized controlled studies with a larger sample size, even multi-center cooperation, must be conducted to confirm the results. In addition, a longer follow-up is essential, especially for those patients with thoracic deformity.