Complete Thoracoscopic Versus Video-Assisted Thoracoscopic Resection of Congenital Lung Lesions

Introduction

Minimally invasive surgery is increasingly recognized as a safe and feasible technique for resecting congenital lung lesions.^1–4 In our hospital, video-assisted thoracoscopic surgery (VATS) was initially performed for these lesions through a 5–6-cm incision after insertion of one or two trocars under differential lung ventilation (assisted-VATS). In 2009, complete thoracoscopic surgery (complete-VATS) with artificial pneumothorax was introduced to our hospital. This method does not require differential lung ventilation and allows for surgery in smaller infants. In assisted-VATS, most of the procedures are done under direct vision of the operative field, whereas the operative procedures in complete-VATS are done under thoracoscopic vision. To our knowledge, there are no reports comparing complete-VATS and assisted-VATS for lobectomy of congenital lung lesions, although several reports have compared complete-VATS and traditional thoracotomy.^5–8

The aim of this study was to compare the outcomes of complete-VATS and assisted-VATS for congenital lung lesions.

Patients and Methods

Between January 2004 and December 2012, 22 children underwent pulmonary lobectomy by complete-VATS (12 children) or assisted-VATS (10 children) at our hospital. We retrospectively reviewed the intraoperative and early postoperative results of these patients, including operative time, intraoperative bleeding amount, duration of chest tube placement, length of hospital stay, and postoperative complications.

For complete-VATS, the child was placed in the lateral decubitus position. If possible, differential lung ventilation was achieved using a bronchial blocker or a double-lumen endobronchial tube. If this could not be achieved, artificial pneumothorax at 4–12 mm Hg with carbon dioxide was used and was sufficient to view the operation. Three or four 5-mm ports were used for the optics and dissection. If a linear cutting stapler was used, one 5-mm port was enlarged to a 12-mm port. To remove the resected tissue, a 3–5-cm incision was made by extending one of the ports between the anterior and posterior axillary lines.

For assisted-VATS, the child was also placed in the lateral decubitus position under differential lung ventilation. Most of the procedures were done using a 5–6-cm incision. A 5- or 7-mm port was used for optics and lighting. If necessary, another 5- or 7-mm port was used for dissection or traction.

Student's t test and Fisher's exact test were used to compare clinical data between complete-VATS and assisted-VATS and to compare clinical data between children weighing <10 kg or ≥10 kg in the complete-VATS group. Values of P<.05 were considered statistically significant.

Results

The demographic data, age at operation, site of the lesion, clinical findings, and histopathologic findings of both groups of patients are shown in Table 1. Of the 22 children, 10 underwent assisted-VATS, and 12 underwent complete-VATS for congenital cystic adenomatous malformation, intralobar sequestration, bronchial atresia, lung tumor, or anomalous systemic arterialization of the lung. In both groups, the side of the lesion was even, and most lesions were located in the lower lobe. The age at operation and body weight were not significantly different between the two groups. Four patients in the complete-VATS group, but none in the assisted-VATS group, weighed <10 kg, indicating that complete-VATS is feasible for smaller children. All the patients in the assisted-VATS group had preoperative respiratory symptoms and experienced pneumonia. By contrast, in the complete-VATS group, 3 patients were asymptomatic, and 5 patients had not experienced infection because of the lesion. Two of the asymptomatic patients were 9 and 15 months old, and both weighed <10 kg. Another asymptomatic patient had anomalous systemic arterialization of the lung and underwent lobectomy because of the risk of hemoptysis.

The intraoperative and early postoperative outcomes of patients in the complete-VATS and assisted-VATS groups are shown in Table 2. The mean operative time was longer, although not significantly, in the complete-VATS group (247±81.7 minutes versus 188.3±41.1 minutes, P=.063). Intraoperative bleeding was significantly less (45.2±56.1 g versus 150.7±153.2 g, P=.047), and hospital stay was significantly shorter (5.8±2.0 days versus 9.0±2.4 days, P=.0043), in the complete-VATS group than in the assisted-VATS group. The chest tube tended to be removed earlier in the complete-VATS group (2.6±1.0 days versus 3.3±0.9 days, P=.10). One patient with congenital cystic adenomatous malformation in the assisted-VATS group had intraoperative bleeding and required conversion to open surgery; no conversions were required in the complete-VATS group. One patient with sequestration in the assisted-VATS group required blood transfusion; no blood transfusion was required in the complete-VATS group. Postoperative complications included transient paralysis of the affected arm caused by intraoperative compression of the brachial plexus and transient atelectasis in 1 patient each in the complete-VATS group.

The demographic data, age at operation, side of the lesion, number of infections caused by the lesion, operative time, intraoperative bleeding amount, and early postoperative outcomes were compared between the children who weighed <10 kg and those who weighed ≥10 kg in the complete-VATS group (Table 3). None of the children weighing <10 kg had an infection caused by the lesion. There were no significant differences between the two groups of children in terms of operative time, intraoperative bleeding amount, or length of hospital stay. These results imply that complete-VATS is feasible for children weighing <10 kg and could avoid inflammatory activity associated with an infection caused by the lesion.

Discussion

Complete-VATS can be safely performed with less bleeding and shorter hospital stay than assisted-VATS. ⁹ We found that the operative field was clearer with complete-VATS and thought that it might achieve less bleeding compared with assisted-VATS.

For differential lung ventilation in small children who are too small to use double-lumen endobronchial tubes, bronchial blockers are usually used. However, these bronchial blockers must be used with an endotracheal tube with a 4.5 mm or larger internal diameter. Although inserting an endotracheal tube deep into the nonaffected side mainstem bronchus could be one of the choices for differential lung ventilation for smaller infants, this method could not effectively deflate the affected side lung and sometimes causes upper lobar atelectasis in the nonaffected side lung by blocking up the upper lobar bronchus. Therefore, assisted-VATS was difficult for the small infants, in whom an endothracheal tube with a 4.5 mm internal diameter could not be inserted. On the other hand, as differential lung ventilation is not essential during complete-VATS, this procedure can be performed in small infants. This introduces new treatment options for small infants with congenital lung lesions. Until now, thoracotomy was the only option for these small infants, and surgery was not widely recommended because chest wall asymmetry, shoulder girdle weakness, and scoliosis-induced pulmonary dysfunction are common in this patient population. ¹⁰

A possible limitation of complete-VATS in small children is the effects of CO₂ insufflation. A collapsed lung on the operative side and compression of the mediastinum could lead to hypoxia, hypercapnia, and hemodynamic changes, especially in small children.^11–13 Therefore, it is essential to monitor vital signs, including end-tidal CO₂ and transcutaneous O₂/CO₂. As artificial pneumothorax should be performed at <5 mm Hg to avoid hemodynamic effects, ¹⁴ we should endeavor to minimize the duration of CO₂ insufflation. If we used a higher CO₂ insufflation pressure, we lowered it after achieving the required view. Additionally, to shrink the emphysematous lesion, which would not deflate, we cut some of the lesion using a vessel-sealing device to obtain an adequate view. However, some patients with congenital heart diseases might be unable to cope with the pneumothorax, or it should be avoided because of the risk of air embolism caused by the right-to-left shunt. Assisted-VATS could be appropriate for these patients.

In our series, all of the children in both groups weighing ≥10 kg with congenital cystic adenomatous malformation, sequestration, or bronchial atresia had an infection caused by the lesion before surgery. By contrast, none of the patients weighing <10 kg in the complete-VATS group had an infection. As infections have inflammatory effects on the lesion, such as adhesions or fissure fusion, early operation might be technically easier than later operation.^4,15–17 Therefore, despite our limited experience, a body weight of <10 kg could be an indicator for easier surgery.

Our next goal is to shorten the operative time of complete-VATS, particularly in small infants, and to make it easier. The recent developments in endoscopic surgical devices could help to achieve this goal. For example, in earlier cases, we often ligated the pulmonary vessels of small infants because there were no devices that could safely seal and divide them. However, ligating small vessels in the chest of small infants is technically demanding, and fragile tissues sometimes tore, causing hemorrhage. The newer vessel-sealing devices cause minimal thermal damage to the surrounding tissues and could achieve secure dissection of pulmonary vessels. Indeed, several innovative tools, including vessel-sealing systems, hemoclips, and linear cutting staplers, were particularly useful for surgical procedures in small infants weighing <10 kg. However, the smallest vessel-sealing device has a 5-mm tip, which may be too large for very small infants. ⁴ Nevertheless, we believe that the operative procedures will become safer and quicker when we have gained further experience in using these innovative tools.

Conclusions

Complete-VATS can be safely performed with less bleeding and shorter hospital stay than assisted-VATS. As differential lung ventilation is not essential in complete-VATS, complete-VATS can be performed in small infants. Recent innovations in surgical equipment, including vessel-sealing systems and linear cutting staplers, may allow for safer and quicker operations using complete-VATS.