Thoracoscopic Lobectomy in Infants and Neonates

Abstract

Video-assisted thoracic surgery is a well-established approach to managing lung pathology in the adult and adolescent population. This minimally invasive strategy has also gained traction for the care of infants and neonates with congenital lung lesions. Thoracoscopic surgery for infants and neonates requires special attention to these patients’ unique physiology. Careful consideration must also be given to lung isolation, the effects of insufflation, and the constraints of small working spaces. Additionally, anomalies such as congenital pulmonary airway malformations have special anatomic considerations including cystic regions and anomalous feeding vessels. However, the basic surgical principles of pulmonary resection apply to infants and children as well as adults.

1. Introduction

Thoracoscopic surgery is a minimally invasive approach to thoracic surgery wherein large intercostal incisions, rib spreading, and rib resection are avoided. Visualization for these cases depends entirely upon video monitors. There are also modified approaches to thoracoscopy where the thoracoscope is used as an adjunct to rib spreading. These approaches are known as video-assisted thoracotomy.

Minimally invasive thoracic surgery dates back to 1910 when Jacobeus treated a patient with tuberculosis by using a cystoscope to induce a therapeutic pneumothorax [1]. The field took a leap forward in 1993 with the use of thoracoscopic surgery for an anatomic lobectomy in a patient with malignancy [2]. Several large series comparing thoracoscopic surgery to open resection were completed during the early 2000s, which demonstrated feasibility, safety, and comparable outcomes—primarily in adult patients with pulmonary malignancy [3, 4, 5]. Later, Steve Rothenberg described a technique for thoracoscopic surgery in infants, which has since proved to be safe and reproducible [6, 7]. This led to the adoption of such techniques by pediatric surgeons, who now regularly make use of smaller instruments and gentle insufflation to achieve good outcomes.

Theoretical benefits to thoracoscopy include decreased postoperative pain, shorter chest tube durations, reduced length of stay, and improved cosmesis. Thus, although traditional surgical approaches such as posterolateral thoracotomy, muscle-sparing thoracotomy, trans-sternal thoracotomy, and median sternotomy remain viable options, thoracoscopy is considered the standard approach in adults when possible. A recent analysis of the Society of Thoracic Surgeons (STS) database demonstrates that thoracoscopic lobectomies account for 45% of all lobectomies performed [8]. Comparable, robust data on the prevalence of thoracoscopic approaches in infants and neonates are not available, but the approach continues to gain favor as the field of pediatric surgery advances.

2. Indications for pulmonary resection in infants and children

2.1 Congenital lung anomalies

Congenital lung anomalies are altogether uncommon, though when present they represent a common indication for surgical intervention in the infant or neonatal chest. Lesions of the lung, which are potentially amenable to surgery, include congenital pulmonary airway malformations, bronchopulmonary sequestrations, hybrid lesions, and congenital lobar emphysema. As prenatal imaging has improved, early identification of each of these lesions has increased, and the literature guiding their treatment has grown. However, specific practice guidelines are lacking, and surgeon judgment remains the driving factor in decision-making. Ultimately, the prognosis of most children with congenital lung lesions is good, and many are candidates for thoracoscopic resection as an alternative to thoracotomy.

2.1.1 Congenital pulmonary airway malformations

Congenital pulmonary airway malformations (CPAMs) are benign cystic masses of abnormal lung tissue in infants and children (Figure 1). They were previously referred to as congenital cystic adenomatoid malformations, or CCAMs, but the name was revised as pathologists began documenting that many of the lesions were neither cystic nor adenomatoid. Now, CPAM is an umbrella term, which includes CCAMs along with sequestrations and hybrid lesions (Figure 2). CPAMs are the most encountered congenital lesions of the lung. They range in severity from those that remain asymptomatic indefinitely to those that cause hydrops fetalis and fetal demise from pulmonary hypoplasia.

Figure 1.

A) Congenital pulmonary airway malformation (CPAM) (*) on the pleural surface B) without arterial vascular supply in the ligamentous attachment (**).

Figure 2.

A) Congenital cystic adenomatous malformation (CCAM) and B) intralobar hybrid lesion with a systemic feeding vessel.

CCAMs are most frequently classified into five groups. Type 0 lesions are exceedingly rare and typically lethal. Here the cysts arise within the trachea or bronchus [9]. Type 1 lesions are the most common, occurring in over 50% of cases, and result from the development of cystic tissue in the distal bronchus or proximal bronchiole. They can become quite large and thus may lead to the development of hydrops [10]. Type 2 lesions are found in roughly a quarter of cases and are frequently associated with congenital anomalies of other organ systems. The extent to which other organ systems are affected defines the prognosis of type 2 lesions. Type 3 lesions occur in less than 10% of cases and are believed to arise from acinar-like tissue. Type 4 lesions are found in about 10% of cases and have been associated with pleuropulmonary blastoma. These lesions are alveolar in origin [11]. Prior to birth, lesions may be classified based on cyst size. Those smaller than 5 mm are termed microcytic, whereas those larger are termed macrocytic. Microcytic lesions are associated with worse outcomes. Types 1, 2, and 4 may present as macrocytic or have elements of both. Type 3 lesions are universally microcytic [12].

CPAM size is an important predictor of outcome. The most used metric is the CPAM volume ratio, CVR. This is the ratio of CPAM/fetal head circumference, where higher ratios are correlated with hydrops fetalis and perinatal morality [13]. Although fetal hydrops is a devastating complication, most patients will be asymptomatic in the fetal and perinatal period. More commonly, patients will be asymptomatic or develop a range of symptoms including respiratory distress, pneumothorax, air leak, pneumonia, empyema, or others contributing to pulmonary abscesses. Up to 25% of initially asymptomatic lesions are expected to become symptomatic, with most of these developing around 6 or 7 months of age [14]. CPAMs may also predispose to, or conceal, malignancy, an outcome that can occur well into adulthood [15].

Symptomatic lesions necessitate surgical intervention. The management of asymptomatic CPAMs, however, is controversial and the potential for these lesions to become symptomatic or mask malignancy must be considered. The objective when operating on an asymptomatic patient is to prevent the development of functional symptoms, pneumonia, or abscess and to mitigate the risk of malignancy.

A 2017 systematic review from the American Pediatric Surgeons Association Committee on Evidence-Based Practice found extensive practice heterogeneity. Most surgeons agreed on the importance of postnatal chest X-ray and CT scan, but consensus could not be reached on optimal timing. Some advised neonatal imaging as early as 6 weeks, whereas others planned for radiographic studies between 3 and 12 months. Resection practices varied as well. Twenty-one percent advise universal resection of asymptomatic CPAMs, 24% recommend observation only for asymptomatic lesions, and the remainder make their recommendation based on lesion size, location, parental preferences, and their suspicion for malignancy [16]. It should be noted that the malignant potential of CPAMs is widely debated. Type 4 CPAMs most strongly predispose to malignancy, though the transformation potential of hybrid lesions and other CPAMs is not well defined [17]. Although there are older studies exploring this topic, the advent of improved prenatal imaging renders them obsolete as we now detected lesions that would have previously gone undetected except at autopsy. In the absence of robust practice guidelines, we favor the latter approach, where the unique presentation of each patient and surgeon judgment are prioritized.

For patients undergoing operative management, anatomic resection is the most common approach for anomalies confined to a single lobe. Early studies suggested that thoracoscopy was a safe and feasible approach that achieved comparable outcomes and shorter length of hospitalization compared with open resection [18]. More recent literature also suggests that thoracoscopic excision may reduce total complication rates [19]. It also mitigates the risk of chest wall deformity, which unlike in the adult population is a real concern for infants undergoing thoracotomy. There is evidence to support the claim the thoracoscopic approach results in less postoperative pain, fewer wound infections, and less long-term musculoskeletal sequelae [20, 21, 22]. These findings should be interpreted with caution, though, as the sample sizes are small. This is a common challenge in pediatric surgery, and ultimately, the surgeons’ skill and judgment should play an important role in selecting the operative approach.

Removal of the cystic tissue allows the normal pulmonary tissue to function at capacity, and for the pathologist to obtain a definitive tissue diagnosis in patients for whom the concern for malignancy is high. It also mitigates the risk of infections in a population predisposed to recurring pneumonia. Although anatomic resection is most common, there are reports of lung sparing (LSR) resections (i.e., wedge resections or segmentectomies). The LSR approach is generally considered feasible and safe, though studies examining long-term outcomes are limited. It offers theoretical benefit over anatomic resection as the infant’s alveoli continue to develop for the first 1–2 years of life [23]. As a result, lung resection during infancy is thought to be less morbid than in adults. No studies to date have examined the theoretical benefit of LSR on pulmonary function, though, and there is no evidence to suggest that the approach is superior to lobectomy for a single, asymptomatic lobar CPAM with regard to either perioperative morbidity or long-term pulmonary function [16]. We thus prefer the lobectomy for its anatomic simplicity and ensuring that the entire lesion is excised.

The optimal timing of surgery in asymptomatic patients has always been controversial. It is theoretically easier to operative in the thorax prior to the development of CPAM complications as they cause inflammatory changes, which result in a hostile operative field [24]. As a consequence, elective resection is associated with better outcomes compared with emergent surgery [25, 26]. Another important consideration for operative timing is that lung growth continues during the early childhood period. This allows for compensatory lung development after resection. So, although immediate postnatal resection is not required, there are advantages to early intervention. The single largest study examining this topic found increased morbidity associated with resection in younger than 3 months of age or less than 5 kg and increased operative time for infants older than 9 months. Thus, the authors recommended deferring elective CPAM resection until the infant was at least 3 months of age, but no older than 9 months [26].

There are also limited reports of fetal pulmonary lobectomy in fetuses with hydrops, though the significant risk of preterm labor and premature delivery must be considered. Other interventions such as pleuro-amniotic shunts can also be completed prenatally, but these operations are only offered at specialized fetal centers [16].

Given the variation in institution and surgeon practice, a robust multicenter study examining risk adjusted outcomes in CPAM patients undergoing resection would be beneficial. The overall rarity of the condition, as is often the case in pediatric surgery, makes this difficult.

2.1.2 Bronchopulmonary sequestrations

Bronchopulmonary sequestrations (BPSs) are masses of lung tissue supplied by anomalous systemic arteries, which do not participate in gas exchange as they are not connected to the tracheobronchial tree. These are the second most common type of congenital pulmonary lesion.

A BPS may be either extra- or intra-lobar depending on their relationship to functional lung tissue. Extra-lobar BPSs are fully separated from the functional lung and are surrounded by their own pleural cover. Intra-lobar BPSs are incorporated into the functioning lung. These lesions are compared in Table 1. BPSs may be identified on prenatal ultrasonography, incidentally during extra-pulmonary surgical intervention, with the development of recurrent pneumonia or abscess. There are also reports of BPS torsion presenting with sudden abdominal or chest pain necessitating immediate resection in a previously well child [27].

Characteristics	Intra-lobar sequestrations	Extra-lobar sequestrations
Proportion	75%	25%
Gender predominance	n/a	Male (3:1)
Extra-pulmonary associations	n/a	Congenital diaphragmatic hernia, vertebral deformities, and congenital heart disease
Location	Medial basal or posterior basal segment of lower left lobe	Left lobe
Diagnostic trends	May be identified prenatally, or during infancy when a child presents with recurring pneumonia or abscess.	Typically identified prenatally or as an incidental finding during surgical repair of an extra-pulmonary defect.

Table 1.

Comparison of intra- and extra-lobar pulmonary sequestrations.

Like CPAMs, BPSs appear as a well-defined homogenous, echo-dense mass on prenatal ultrasonography. They can be distinguished from CPAMs by the presence of doppler flow from a systemic artery to the lesion. This finding, however, is not universally demonstrated on ultrasound, and an MRI may be necessary to distinguish between the two. CT may also be indeterminate (Figure 3).

Figure 3.

A) Axial and B) coronal CT imaging of a prenatally diagnosed pulmonary lesion of unknown etiology.

Like CPAMs, the management of asymptomatic lesions remains controversial. It should be noted that intra-lobar lesions have an increased risk of developing symptoms, particularly those related to infection, as their connection to the functional lung tissue and the bronchopulmonary tree allows for sequestration of infectious material. Additionally, intra-lobar sequestrations are fed by arterial vessels, which most commonly arise from the abdominal aorta and may require repair of a diaphragmatic defect if traversed (Figure 4). These can, in some unfortunate cases, result in pulmonary overcirculation or symptomatic shunting. Both scenarios are indications for resection and preoperative embolization should be considered to mitigate intraoperative bleeding risk.

Figure 4.

A) Intralobar sequestration (*) with aortic vascularization (**) before and B) after transection with subsequent repair of diaphragmatic defect (***).

Ultimately, BPSs are monitored and managed similarly to CPAMs, with comparable variations in practice between surgeons and institutions [28, 29]. Though special attention must be paid to resection and ligation of the feeding vessels when pursuing surgery. These technical details are described in detail later in the chapter.

When surgery is performed by a surgeon well versed in thoracoscopy, outcomes with thoracoscopic surgery are comparable to thoracotomy in this population [30]. And recent evidence demonstrates the safety of this approach when applied by appropriately supervised trainees [7]. There are limited reports of a hybrid and endovascular approach to management as well, though surgical resection remains the gold standard when intervention is indicated. As prenatal imaging continues to improve, rigorous practice guidelines should be developed to guide management of these increasingly diagnosed lesions.

2.1.3 Hybrid lesions

Pulmonary lesions with findings suggestive of both CPAM and BPS are possible. These are referred to as hybrid lesions, and as with the constituent defects they represent, evidence-based guidelines for management are scarce. Surgeon judgment and patient presentation are the dominant forces driving management. Consideration should be given to what has been previously described about CPAMs and BPSs.

2.1.4 Congenital lobar emphysema

Congenital lobar emphysema (CLE) is the overdistention of pulmonary tissue resulting from airway obstruction. This may affect a segment, portion of a lobe, or an entire lobe. As with the other lesions described in this chapter, CLE may be diagnosed on antenatal imaging, or be identified in the setting of a symptomatic child. Half of patients are symptomatic at birth and almost all the remainder develop symptoms within the first 6 months of life. It is uncommon to identify CLE in an asymptomatic child.

The infant with congenital lobar emphysema presents with acute, life-threatening respiratory distress. CLE has a 3:1 predominance for male infants with implication of the upper lobe being most common. Only infrequently are the lower lobes involved. Bi-lobar involvement is rare but described [31]. Chest X-ray is usually diagnostic and demonstrates hyperinflation of the involved lobe with compression of the contralateral lung and mediastinal shift [32].

Management of CLE depends on severity of presentation. Nonoperative management is recommended in patients with mild to moderate symptomatology. In the presence of severe pulmonary disfunction or ongoing clinical progression, the gold standard approach to management is a lobectomy. Transient lobar occlusion with balloon endoscopic balloon dilation has been suggested as a mechanism for evaluating the impact of surgical resection a priori in patients for whom surgical management is equivocal [31].

It is important to state that CLE must not be confused with a tension pneumothorax, as placement of a chest tube into the overinflated lung can be disastrous. Additionally, since the respiratory distress is of obstructive rather than restrictive etiology, intubation and positive pressure ventilation can worsen respiratory function by forcing more air into the lungs and further expanding them. Expert neonatologists and anesthesiologists should be involved in the care of these infants, who are often managed non-operatively.

Unique from the previously discussed congenital lung lesions, thoracoscopic management is actually contraindicated for CLE as the overinflated lobe limits access to the chest. This makes thoracoscopic dissection in the neonate difficult and dangerous for patients with these lesions [22, 33, 34].

2.2 Malignancies

Malignancy of the pediatric chest is a rare event that when present should prompt consideration of pulmonary resection along with adjuvant therapy, the latter of which is beyond the scope of this text. Malignancies can be primary, most often pleuropulmonary blastoma, or more frequently metastatic. Metastatic disease most often results from osteosarcoma, Wilms tumor, and hepatoblastoma. Thoracoscopic intervention has been compared with open resection in this population, with thoracoscopic wedge resection now representing the most common therapeutic modality.

2.2.1 Pleuropulmonary blastoma

Pleuropulmonary blastomas (PPBs), though infrequently occurring (estimated incidence is 25–50 cases per year in the United States), are the most common primary pediatric pulmonary malignancy. They are associated with DICER1-related disorders, which have been described in detail elsewhere [35]. For the purposes of this text, it should be noted that this affiliation can result in concurrent primaries outside of the lungs and that all children with PPBs should undergo a thorough workup for additional malignancy, which includes genetic testing for a DICER1 mutation. Children with PPBs present with nonspecific findings that most frequently include respiratory distress, chest pain, and fever. It is uncommon to identify a PPB in the asymptomatic child.

PPBs progress through well-defined stages, which allows for them to be categorized into three unique types, where each corresponds to a different prognosis (Table 1). They are categorized based on the presence of cystic and solid components. There is some debate as to whether a type 1 lesion may regress (Type 1r) through the loss of malignant tissue. The controversy is that it is unclear whether these masses ever possessed a malignant component to begin with. Regardless, these lesions seem to be clinically insignificant, as the small number of patients who died after detection of a Type 1 mass experienced progression to Type 2 or 3 rather than Type 1r. No such regression has ever been described in Type 2 or 3 lesions (Table 2).

	Type 1	Type II	Type III
Tissue type	Purely cystic	Cystic & solid	Purely solid
Frequency	1/3 of diagnoses	1/3 of diagnoses	1/3 of diagnoses
Age at diagnosis	Median: 8 months 95% by 36 months	Median: 35 months 95% by 81 months	Median: 41 months

Table 2.

Comparison of pleuropulmonary blastoma types.

In comprehensive analyses of the PPB Registry, only type and metastases were identified as prognostic factors. Smaller cohort series have also suggested that the ability to achieve complete surgical resection may be prognostic, though this is debated. DICER1 mutations, found in up to two-thirds of patients, are common but definitively not prognostic. Nearly one-third of patients have a family member with a diagnosis within the DICER1 syndrome, including Wilms tumor, stromal tissue tumors, thyroid malignancy, cervical rhabdomyosarcoma, renal sarcoma, and pulmonary sequestration, to name a few [36].

A consensus on surgical management is not currently available, but reviews exist to guide the surgeon’s approach and surveillance. Consideration should be given to the fact that these lesions may be mistaken for the previously described benign CPAMs, and that PPBs may progress from surgically amenable cystic masses (Type 1) to lethal metastatic disease with solid components (Type 2 or 3) if not managed promptly. The clinical feature best used for distinguishing CPAM from PPB is a systemic feeding vessel. But as has been stated previously, this not always found on imaging. Prenatal detection and pulmonary hyperinflation have also been suggested for their association with CPAM over PPB. On the other hand, multi-lobar or bilateral abnormalities, complex cystic tissue, and mediastinal shift are all associated with PPB over CPAM. All children with cystic lung lesions should be considered for DICER1 testing to further assess their risk [37].

Patients with Type 1 disease are curatively managed with surgery alone when resection with negative margins and no tumor spillage is achieved. A wedge resection is most common, though lobectomy or other larger resections may be indicated for lesions with central, hilar, or multifocal involvement. Most authors have advocated for an open approach to the management of these lesions given the risk associated with tumor spillage. Smaller lesions, however, can be approached thoracoscopically by the surgeon adept in minimally invasive techniques [38].

Patients with Type 2 or 3 malignancy will often require adjuvant chemotherapy to minimize the resection necessary to achieve local control. Fortunately, PPBs are highly chemosensitive tumors, and neoadjuvant therapy can achieve a dramatic reduction in tumor size in patients for whom upfront surgery is deemed inappropriate. In general, the literature advocates for open resection in this population as increased size and tumor complexity make achieving a negative margin and spill-free resection difficult via a thoracoscopic approach. Lobectomy or pneumonectomy may be necessary to achieve adequate margins, and pleural surfaces should be taken en bloc with the implicated lung tissue.

In cases with extensive pleural spread, extra-pleural pneumonectomy may be necessary. This requires careful resection of the pleural surfaces, pericardium, diaphragm, and phrenic nerve along with division of the pulmonary hilar vessels. Children undergoing such extensive resection have a high rate of postoperative complications, most notably post-pneumonectomy syndrome. Unfortunately, PPB can progress or recur in patients with Type 2 or 3 disease, and both result in dramatically reduced survival [37].

The low incidence of childhood cancers is a defining challenge for the teams that manage them. A lack of robust clinical trials means that treatment algorithms are often driven by expert opinion and physician judgment based on retrospective and registry data. For PPB specifically, treatment options include surgery and chemotherapy as outlined here. The timing for each depends on the type and complexity of PPB. Ultimately, complete surgical resection is required for cure. Advancing the care and understanding of children with PPB will require cooperation across international study groups to organize prospective clinical trials.

2.2.2 Pulmonary metastatic disease

In addition to primary malignancy of the lung, pulmonary metastatic disease is an indication for surgical intervention of the infant or neonate. In fact, this is far more common than primary pulmonary malignancy. The most frequently implicated primaries are osteosarcoma, Wilms tumor, and hepatoblastoma (Figure 5). Metastasectomy has shown benefit for children with each of these malignancies, though pulmonary resection itself is not benign. The presence of uncontrolled primary disease and an inability to maintain adequate lung function after pulmonary resection are absolute contraindications to metastasectomy, regardless of primary.

Figure 5.

A) Wilms tumor of the right kidney with B) blue vessel loops encircling the tumor’s venous outflow.

Historically speaking, outcomes for children requiring pulmonary metastasectomy have been poor and difficult to study. Early literature was limited by its histologic heterogeneity, but more recent studies have illuminated some key points. We now know that staged bilateral resections are well tolerated and that the extent of metastasis is not an absolute contraindication to metastasectomy. This is largely the result of the now frequently utilized pulmonary wedge resection, which permits multiple lesions from both lungs to be excised while preserving non-diseased lung tissue. From a diagnostic perspective, CT has long been the gold standard for detecting pulmonary nodules. CT, however, lacks specificity and is unable to distinguish benign from malignant nodules. In the absence of tissue biopsy, this can lead to false positives and unnecessary surgical interventions [39]. Thus, thoracoscopy has a role in both therapy and diagnostic biopsy.

Wilms tumor is the most common pediatric solid tumor malignancy. Despite overall excellent outcomes for children with this diagnosis, patients with pulmonary metastasis fare poorly. Wilms tumor is responsive to radiotherapy, so whole lung radiation is commonly used for the management of pulmonary metastasis. In patients who do not respond to initial chest radiation, the Children’s Oncology Group (COG) advocates diagnostic biopsy of lung nodules to minimize further exposure to toxic therapy in the cohort of patients with benign lesions. Minimally invasive approaches to metastasectomy are widely accepted in this cohort.

Hepatoblastoma also has dramatically decreased survival in children with pulmonary metastasis. Hepatoblastoma is sensitive to chemotherapy, and metastasectomy has been shown to be effective. Thus, the COG recommends a combined approach with neoadjuvant chemotherapy and subsequent total resection of the primary tumor and any pulmonary metastasis. Minimally invasive approaches to metastasectomy are widely accepted.

High-grade osteosarcoma accounts for roughly 5% of childhood malignancy. An important predicator of survival in this population is the presence of metastasis, and the lungs are the most common site for distant spread of malignancy. Though up to 10% of pulmonary metastasis are expected to regress with neoadjuvant chemotherapy, the remainder require surgical resection [40]. Interestingly, the timing of pulmonary metastasis is an important prognostic factor in children with osteosarcoma. Patients who experience pulmonary metastasis during chemotherapy have the worst survival [41].

Unlike metastasectomy for Wilms tumor or hepatoblastoma, there has historically been vigorous debate about the use of thoracoscopic resection in patients with osteosarcoma. The discussion has hinged on the fact that direct palpation of the lung via thoracotomy had been shown to detect osteosarcoma metastases that were not identified on CT. The impact of such lesions on survival, however, was not well understood and most treatment was based on surgeon judgment.

Recently, though, a multi-institutional collaborative group compared overall and disease-free survival in patients with metastatic osteosarcoma undergoing thoracoscopy and thoracotomy. They found equivalent overall and pulmonary disease-free survival in patients with oligometastatic pulmonary disease. Thoracoscopy, however, was associated with inferior overall survival when including patients with greater pulmonary burden. Ultimately, further investigation is still needed to determine the best strategy for treating osteosarcoma patients with pulmonary metastasis [42, 43]. Work in this area is ongoing, and the Children’s Oncology Group has launched a randomized controlled trial comparing thoracoscopic interventions with bilateral staged thoracotomies in children and adolescents with oligometastatic osteosarcoma [44].

In conclusion, though children with solid tumors fare much better than in decades prior, pulmonary metastases still portend worse outcomes, regardless of primary histology. Surgery has a role to play in both diagnostic and therapeutic settings. Thoracoscopy is widely accepted for most metastasectomies, but evidence is limited on the potential benefits of lung palpation via thoracotomy in patients with osteosarcoma who may have radiographically undetectable pulmonary lesions.

2.3 Diagnostic dilemmas

In some groups of children, pulmonary resection is indicated due to diagnostic dilemmas. These typically occur when nodules or consolidations of unknown etiology develop and may represent malignancy or infection. This is observed in children requiring hematopoietic stem cell transplantation and immunosuppression. In these patients, such radiographic findings could result from infectious complications from their immunotherapy, progressive disease burden, or less frequently graft-versus-host disease. Thoracoscopic wedge resection with pathologic investigation of such ambiguous lesions is appropriate, as the potential for infection and malignancy have been described throughout this chapter [16, 19, 23, 25].

Another challenging situation occurs in the neonate suspected to have alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV), which results from premature arrest of pulmonary development [45]. Although rare, the diagnosis should be considered in a neonate with unexplained persistent pulmonary hypertension (PPHN) [46]. Presentation is variable, but most infants have early onset respiratory distress [47]. Others will have a delayed presentation weeks to months after delivery [48]. A variety of coincidental defects in the cardiovascular, gastrointestinal, and urogenital systems have been documented [49]. Chest radiographs may demonstrate diffuse haziness or ground glass opacities but are frequently read as normal [50]. Echocardiograms can be useful for evaluation potential cardiac causes of PPHN.

Children with early onset symptoms typically demonstrate transient response to vasodilators, mechanical ventilation, and extra-corporeal membrane oxygenation but ultimately deteriorate and succumb to their disease without a transplantation [51, 52, 53]. Definitive diagnosis depends on surgical biopsy and tissue review by an experienced pediatric pathologist. Diagnostic clarity is essential in these cases as the prognosis is poor and early goals of care conversations are required.

3. Lobectomy considerations for infants and neonates

Thoracoscopic pulmonary resections are a well-described alternative to more invasive approaches to lung surgery in the adult and adolescent population. As has been described throughout this chapter, there is broad applicability of this approach to the infant and neonatal population with congenital or malignant abnormalities of the chest. Many of the same considerations from adult surgery apply, but a few are unique to the pediatric population. They are outlined here.

3.1 Lung isolation

Single lung ventilation is often necessary for successful thoracoscopic intervention as the lung is unable to be manually retracted. In adults and adolescents, there are a variety of options available to achieve this, including selective mainstem intubation, double lumen endotracheal tubes, Univent endotracheal tubes, and bronchial blockers. Neonates and infants, however, have smaller thoracic anatomy, which precludes the use of double lumen endotracheal or Univent tubes. Thus, selective mainstem intubation or bronchial blockers are required, though neither provides the same effectiveness as double lumen endotracheal tubes [54].

A major limitation to mainstem intubation is that the anesthesiologist cannot quickly change between single and two-lung ventilation as can be done with a double lumen device. Instead, they must reposition the endotracheal tube, which can result in accidental extubation. It should also be noted that mainstem intubation is particularly difficult on the left side, owing to the more acute angle of this bronchus.

Bronchial blockers can be used as an alternative to mainstem intubation. There are several candidate devices, including Fogarty catheters, pulmonary artery catheters, or the Arndt endobronchial blocker. Each of these can be used to occlude the bronchus on the operative side. The risk here is that the device becomes dislodged during the operation and occludes the tracheal lumen causing inadequate ventilation.

These considerations, although important, should not be prohibitive. Just as we advocate for neonatal thoracoscopic intervention in the hands of a skilled minimally invasive surgeon, so too attention should be placed on selecting an appropriately trained anesthesia staff with skills in neonatal intraoperative management. Such circumstances are a prerequisite for success during minimally invasive thoracic surgery of the infant or neonate [54].

3.2 Anatomic principles of lobectomy

In general, the anatomic principles of lobectomy are similar in neonates, adolescents, and adults. Only the necessary amount of lung for negative margins should be resected to maintain pulmonary function. Care should be taken to operate in an atraumatic fashion and to achieve hemostasis before closure. Respect for the anatomic boundaries and plains of the lungs is paramount. The neonatal circulation has a much smaller overall blood reserve, so volume losses can be detrimental. It is generally safer to take vessels at the segmental level instead of main trunks, and this is more easily done thoracoscopically.

In patients undergoing nonanatomic resections, either due to incorporation of multiple lobes into the lesion, or the presence of fissure fusion, the Ligasure has been recommended to complete a multi-segmentectomy [6].

3.3 Thoracoscopic techniques

Thoracoscopic lobectomy was first described in children by Steve Rothenberg for management of neonates with asymptomatic prenatally diagnosed lesions. He demonstrated that the skilled minimally invasive surgeon could safely and efficaciously apply thoracoscopic surgery to the small child in need of therapeutic lobectomy. Prior to this, the small size of young infants left surgeons unsure if their working space would be adequate for the large instrumentation required to complete a thoracoscopic resection.

His initial discussion of the thoracoscopic approach to neonatal lobectomy was limited to the previously discussed congenital lung malformations, but it now has broader applicability to the malignancies also mentioned in this chapter. Here we outline the modern technical details, which are built on his original approach [7].

Patients are placed in the lateral decubitus position and single lung ventilation is achieved via any of the approaches previously described for neonates. The surgeon and their assistant stand anterior to the patient while facing the surgical monitor. The first trocar is inserted, typically with an open technique, via the appropriate intercostal space based on the planed resection. As with other forms of minimally invasive surgery, the surgeon should attempt to “triangulate” their target for maximum maneuverability with the thoracoscopic instruments (Figure 6). If necessary, pneumothorax can be induced via insufflation with CO₂. Two to three additional ports are placed under video guidance based on appropriate surgical planning. These will be used for the dissection instruments and sealing device, typically a curved bipolar.

Figure 6.

A) Port placement for upper and B) lower lobectomy.

The relevant fissures and lobar vessels are dissected and sealed using the electrocautery. Endoclips should be considered if the patient has a pulmonary sequestration, as care must be taken to ligate the systemic feeding artery. The bronchus is sharply divided and closed intracorporeally using the surgeon’s preferred approach. This may include suturing or stapling. The former requires adeptness with intracorporal suturing, though the latter necessitates a larger incision. After completing the lobectomy, the upper incision is lengthened, and the lobe is withdrawn. If the specimen contains malignancy, special attention is given to avoid spillage. A chest tube is left in place.

4. Pneumonectomy and other anatomic resections

4.1 Surgical principles

The principles of pneumonectomy, other anatomic resections, and wedge resections are similar in adults and children. Indications, as described above, include congenital pulmonary airway malformations, bronchopulmonary sequestrations, emphysema, and primary or metastatic malignancy. Lobectomy with en bloc tumor resection is the standard for patients with resectable cancers. Less extensive resections such as segmentectomy are chosen for patients who cannot tolerate lobectomy due to concern for limited pulmonary reserve [55].

The surgery is completed with the patient in the lateral decubitus position and the pleural space is entered through a posterolateral incision to provide exposure of the lung hilum. Inspection of the pleural space is performed; cytology and culture of any pleural fluid are completed as indicated. Arterial and venous supplies are identified, dissected, and divided at the hilum. Care should be taken not to injure the phrenic nerve when operating in the anterior hilum. Chest tubes are placed to drain residual fluid and support expansion of the residual lung.

4.2 Redo surgery

Redo thoracoscopic surgery is fraught with challenges and requires a special attention to relevant anatomy [56]. Adhesions and scar tissue contribute to a difficult operative field, just as in the adult population [57, 58]. There is precedent for approaching redo operations of the neonatal chest thoracoscopically, and we support such a strategy based on individual surgeon judgment. Still, preparations should be in place in the event that the case must be converted to open [59]. In rare circumstances, an intrapericardial approach to lobectomy or pneumonectomy can be considered in the extremely hostile reoperative chest [60, 61].

5. Perioperative complications of thoracoscopic surgery in neonates and infants

The feasibility and safety of thoracoscopic intervention have been rigorously reviewed in the adolescent population. It has been shown that the approach is not associated with increased risk compared with open surgery, while maintaining the previously described benefits of minimally invasive surgery. It is less thoroughly described in the infant and neonatal population, though we have discussed the common indications and emerging body of evidence, which supports its use in appropriate circumstances.

Reports of major complications from infant and neonatal thoracoscopy are limited but are summarized by a 2018 review published in the European Journal of Pediatric Surgery. Limited reporting of complications, small sample sizes, and study heterogeneity prevent the calculation of definitive complication rates in this population. Reported rates likely underestimate the true incidence due to reporting bias. Increased reporting of complications along with longitudinal patient series is encouraged to promote increased understanding of outcomes in this area and to guide decision-making when operative indications are equivocal [62].

5.1 Bleeding

Bleeding is one of most common complications in infants and neonates undergoing thoracoscopic surgery. This is of particular importance in the pediatric population given the limited total blood volume. Careful communication with anesthesia is essential to ensure that appropriate blood volume is available at the beginning of a case. There are also several instruments available for management of the bleeding vessel or tissue, including Heme-o-lok clips, pretied ligatures such as the ENDOLOOP, and stapling devices. Energy sources can also be used to achieve hemostasis, with LigaSure, HARMONIC, and Ultrasonic shears being common examples. Care should be given to not damage surrounding tissue when achieving hemostasis with the application of heat, as this can result in its own set of complications, which ironically enough can include additional bleeding. Intracorporeal suturing is also an option [7]. Whatever the approach, rapid control of bleeding is essential and proceeding with a large open thoracotomy is sometimes necessary.

5.2 Air leak

Persistent air leak is another commonly encountered complication of thoracoscopic surgery in neonates and infants. There are no evidence-based guidelines available for the management of this problem. Individual reports have demonstrated success with insertion of a secondary surgical chest tube, which has typically resulted in air leak resolution within a few days. In cases where the air leak has continued, reoperation with closure of a defect may be required. Chemical pleurodesis is well described in the adult population, but use of such toxic agents is discouraged in the pediatric population. There are limited reports of “autologous blood patching” wherein a bolus of the patient’s own blood is injected into the pleural cavity through their chest tube [63]. Finally, there is a report of endobronchial occlusion of valves [64].

5.3 Conversion to open

Conversion is an outcome that must be considered in all approaches to minimally invasive surgery, including thoracoscopy. Bleeding, poor visualization, lesion size, pulmonary congestion, dissection difficulty, and the presence of unexpected lesions are all potential causes of conversion [62].

6. Conclusions

Thoracoscopic lobectomy is a strategy for surgical management of a wide range of pulmonary diseases in infants and children. These include congenital malformations, malignancies, and infections. There are similarities to resection in the adult population, but important differences exist too. The unique anatomic and physiologic principles of pediatric patients must be considered during surgical planning. The outcomes of these resections depend primarily on the underlying pathology.

Conflict of interest

The authors declare no conflict of interest.