Thoracoscopic Approaches to Congenital Lung Lesions



Fig. 14.1.
Prenatal MRI of a twin gestation fetus with multilobar CPAM. Arrow points to the affected fetus and the lung.





Preoperative Evaluation and Treatment


Management of a fetus with a cystic pulmonary lesion is dependent upon the symptoms present. Prenatal management of CPAM may consist of steroid treatment in fetuses with a CVR greater than 1.4. Betamethasone has been shown to arrest growth of CPAM with subsequent improvement in hydrops symptoms [8]. A fetus that has been diagnosed with a macrocystic CPAM complicated by hydrops may be treated with thoracoamniotic shunting. Microcystic or solid CPAMs that present with hydrops have been approached with fetal surgery [9]. A late gestation fetus with hydrops may benefit from an ex utero intrapartum therapy (EXIT) approach [4, 10]. The fetus with a CPAM without hydrops should be managed with planned delivery and neonatal evaluation and eventual surgery.

All newborns prenatally diagnosed with a congenital pulmonary lesion should have a baseline radiograph at the time of birth. Surgical management should be based upon whether the newborn is symptomatic from the lesion. Infants with hemodynamic or significant respiratory compromise may need immediate resection. Extracorporeal membrane oxygenation (ECMO) has been used in some of these cases [2]. Persistent tachypnea, oxygen requirement, poor weight gain, and inability to feed orally are indications for early resection prior to discharge from the hospital. Asymptomatic children may be discharged and followed up as an outpatient. At our institutions, we typically perform preoperative imaging using computed tomographic scans at 3 months of age. Lesions are typically isolated to a single lobe; however, multilobar CPAM has been documented and will affect surgical decision-making (Fig. 14.2). It may be difficult to differentiate an extralobar sequestration from an intralobar sequestration radiographically. Attention should be paid to look for a systemic blood supply to the lesion to assist in differentiation of CPAM from BPS. Additionally, identification of a subdiaphragmatic feeding vessel will assist with operative planning (Figs. 14.3 and 14.4).

A336954_1_En_14_Fig2_HTML.jpg


Fig. 14.2.
CT scan showing multilobar CPAM involving the entire right lung.


A336954_1_En_14_Fig3_HTML.jpg


Fig. 14.3.
CT scan showing a systemic feeding vessel to a right pulmonary BPS. Arrow identifies vessel. This vessel ultimately arose from the celiac plexus.


A336954_1_En_14_Fig4_HTML.jpg


Fig. 14.4.
Systemic feeding vessel of intralobar bronchopulmonary sequestration.


Technique


Resection of pulmonary lesions has been classically performed through a posterolateral thoracotomy . Over the last decade and a half, surgical resection through a minimally invasive approach has become more commonplace. We recommend surgical resection, using a minimally invasive approach, when the infant is 3–6 months old. Children who present with infected lesions are recommended to undergo adequate antibiotic therapy for the infection prior to resection of the lesion. Minimally invasive approach is still a viable option in children who have had pneumonia; however, there has been a documented increase in conversion to open thoracotomy in these children [11].


Minimally Invasive Approach


The child should be placed in the lateral decubitus position with the affected side up. Adequate padding of all bony prominences as well as proper positioning of an axillary roll should be ensured. Small gel rolls, placed anteriorly and posteriorly, are adequate to prevent patient movement in younger children. In older children, we use a beanbag underneath the patient as our preferred method of stabilization. Central venous lines, arterial lines, and bladder catheters are not required intraoperatively. Management of the airway requires an anesthesiologist experienced in pediatric airways to ensure adequate single-lung ventilation. A techniques available for isolating the contralateral lung includes double-lumen endotracheal tube in older children and adolescents. In younger children, a Fogarty balloon catheter (Edwards Lifesciences, Irvine, CA) may be used as an endobronchial blocker with placement of a single-lumen endotracheal tube. This technique is more difficult in children less than ~5 kg because the bronchial blocker itself fills much of the lumen of the endotracheal tube making ventilation more difficult. We have passed the blocker extraluminally in order to alleviate this problem. Infants may require main stem intubation of the contralateral bronchus due to the narrow airway [11]. The use of a mild tension pneumothorax may also be useful in helping to collapse the ipsilateral lung and improve visualization. We use a pressure of no more than 4–5 mmHg. Flexible bronchoscopy is necessary to ensure proper placement of the endotracheal tube and bronchial blocker during initial placement and after repositioning of the patient. We do not place epidural catheters for pain management except in rare instances when conversion to an open procedure is needed.

The surgeon and assistant both stand on the same side of the patient depending on the lobe to be resected. We prefer to stand at the front of the patient with the monitor at the patient’s back for lower lobes and the reverse for upper lobes. Local anesthetic is infiltrated at each trocar site. A veress needle is used to enter the chest cavity through a Step radially expanding sheath (Medtronic, Minneapolis, MN). Alternatively, a direct cutdown and placement of the initial trocar and reusable trocars may be used. The hemithorax is then insufflated with low-flow, low-pressure carbon dioxide to aid in collapse of the affected lung. This initial entry site is typically through the fifth or sixth intercostal space beneath the tip of the scapula in the anterior axillary line for lower lobes and the posterior axillary line for upper lobes. Entry at this site will allow for visualization of the major fissure and the underlying pulmonary parenchyma [12] (Fig. 14.5). Subsequent ports are then placed such that the camera port overlies the fissure. We typically use three 5-mm ports (two working ports and one camera port). In smaller babies we often use two 3-mm ports and one 5 mm to allow for use of the Ligasure (Covidien Energy Devices, Boulder, CO). For upper lobes all ports are placed in line in the posterior axillary line, while lower lobes have the ports placed in line in the anterior axillary line (Figs. 14.6 and 14.7). A fourth stab incision for insertion of an instrument to assist with parenchymal retraction or suction is placed in the lower chest in the 8–9th interspace. We use the anterior and posterior axillary lines as landmarks because it allows the operating surgeon to place the venous anatomy of the lung lobe between themselves and the monitor while the arterial anatomy is always fixed within the fissure. Alternatively, surgeons may choose to adopt a triangulation method with placement of ports in the anterior, posterior, and midaxillary line using the location of the lesion as the focal point of the triangle.

A336954_1_En_14_Fig5_HTML.gif


Fig. 14.5.
Image on initial entry into thoracic cavity overlying major fissure. Affected lobe is in the superior portion of the image.


A336954_1_En_14_Fig6_HTML.jpg


Fig. 14.6.
Recommended port placement along posterior axillary line for upper lobe lesions.


A336954_1_En_14_Fig7_HTML.jpg


Fig. 14.7.
Recommended port placement along anterior axillary line for lower lobe lesions.

Resection of pulmonary lesions is typically through formal lobectomy. In the case of multiple lesions affecting multiple lobes, segmental resection may be appropriate to preserve pulmonary parenchyma. The steps in dissection vary depending upon the affected lobe and follow the same principles as open thoracotomy [13]. Completion of the major and minor fissure allows for visualization of the pulmonary vasculature and segmental artery branches. Division of the arterial branches is followed by division of the pulmonary veins (Fig. 14.8). Initial division of the pulmonary artery prevents parenchymal congestion and preserves the intrathoracic work space. The Ligasure has proven to be an effective method of dividing pulmonary parenchyma to complete division of the fissure. This device has also been shown to be an effective method of division of pulmonary vessels <7 mm in size. We currently use either the LS 1500 5-mm laparoscopic sealer/divider or the LF 1737 laparoscopic sealer. The LS 1500 has a blunt dolphin-tip while the LF 1737 has a Maryland tip. The Maryland tip we find beneficial for dissection especially around vessels. Multiple vessel sealing devices are available currently (Harmonic, Gyrus, JustRight sealer); however, we have routinely utilized the Ligasure system. For larger vessels, control with an endoscopic hemoclip (Auto Suture ENDO CLIP, Covidien) or with intracorporeal suture ligation followed by division using an energy-based sealing device has been described [11, 14].
Oct 25, 2017 | Posted by in PEDIATRICS | Comments Off on Thoracoscopic Approaches to Congenital Lung Lesions
Premium Wordpress Themes by UFO Themes