Simultaneous unilateral thoracoscopic resection of bilateral pulmonary sequestration

Abstract

Background

Intra-lobar (ILS) and extra-lobar lung (ELS) sequestrations represent rare congenital lung malformations. Despite their benign nature, the lesions pose risks such as recurrent pulmonary infections, hemoptysis, congestive heart failure, and tumor development. Pulmonary sequestration (PS) typically manifests in two forms, ILS and ELS, with bilateral occurrence being exceptionally rare and mostly requiring bilateral thoracic surgery.

Case presentation

A 9-year-old child, who initially presented with bilateral lung lesions without respiratory symptoms, was diagnosed with PS following a chest computed tomography scan. The surgical approach was determined based on the absence of inflammation and the clear demarcation of the lesions from normal lung tissue, highlighted by a unique tissue connection between the ILS and ELS across the chest cavities. We used a novel method wherein the left ELS was successfully pulled into the right chest cavity and both sequestrations were concurrently resected. Postoperative recovery was smooth, with no complications or residual lesions.

Conclusions

Our findings highlight the importance of thorough preoperative planning with enhanced computed tomography. Simultaneous unilateral thoracoscopic surgery can be a viable, less invasive option for treating bilateral PS, offering benefits such as reduced recovery time and better cosmetic outcomes.

Background

Congenital pulmonary sequestration (PS) is a rare malformation, accounting for 0.15–6.4% of all lung deformities [1]. Typically unilateral, bilateral PS is exceptionally uncommon [2]. PS presents as intra-lobar PS (ILS) and extra-lobar lung sequestration (ELS), with ILS representing 80% of the cases. To our knowledge, only five reports exist on bilateral ILS and ELS [3,4,5,6,7]. Given the separate lesions on each side of the chest, surgical methods include staged bilateral thoracotomy and simultaneous bilateral thoracoscopic surgery, both of which require bilateral thoracic surgery.

In this case report, we present a unique case of a 9-year-old child undergoing a successful simultaneous unilateral thoracoscopic resection of bilateral ILS and ELS, which resulted in positive outcomes. Notably, no prior reports exist for this treatment method.

Case presentation

A 9-year-old female patient underwent a chest computed tomography (CT) scan at a local hospital two months ago, revealing bilateral lung lesions. Seeking further treatment, her parents brought her to our hospital, where we diagnosed congenital PS or congenital pulmonary airway malformation. Although the patient was asymptomatic, her parents don’t want to bear the risk of lung infections and tumorigenesis, actively requesting surgical treatment. We admitted her for treatment, noting the absence of pneumonia, chest pain, shortness of breath, wheezing, or breathing difficulties.

Post-admission, a chest-enhanced CT scan showed an ILS on the right and an ELS on the left, with no inflammation and featuring a larger ELS (Fig. 1A). A tissue connection between the bilateral lesions is located between the descending thoracic aorta and esophagus (Fig. 1B). The common anomalous supply artery trunk originated from the abdominal aorta, branching out to supply the ILS and ELS. The reflux of the ILS and ELS occurred into the right inferior pulmonary vein (Fig. 1C, D).

Fig. 1

Preoperative chest CT reveals: (A) Right ILS and left ELS, ELS bigger, distinct boundaries between the lesions and the normal lung tissue. (B) Tissue connection between ILS and ELS. (C) Bilateral branches of abnormal supply arteries and return veins. (D) Common trunks of the abnormal supply arteries and return veins. (◆: Intra-lobar pulmonary sequestration (ILS), ★: Extra-lobar lung sequestration (ELS), ↑: Connection tissue between ILS and ELS, ●: Aorta artery, ▲: Common trunk of the abnormal supply arteries, ▼: Common trunk of the abnormal return veins, ◥: ILS branch of the abnormal supply arteries, ◤: ELS branch of the abnormal supply arteries, ◢: ILS branch of the abnormal return veins, ◣: ELS branch of the abnormal return veins)

We designed a surgical plan based on the enhanced CT results, considering the absence of inflammation in the right ILS and a clear boundary between the ILS and normal lung tissue, making thoracoscopic wedge resection feasible. Notably, a tissue connection between the right ILS and left ELS with the common trunk abnormal supply artery was observed. The return vein of the ELS flowed into the right inferior pulmonary vein in the right chest cavity, with no connection to the left thoracic vein. We attempted to separate the space between the descending thoracic aorta and esophagus, pulling the left ELS into the right chest cavity, disconnecting the common trunk abnormal supply artery, and simultaneously resecting the ILS and ELS. If pulling the ELS into the right chest cavity proves challenging due to the small gap between the descending aorta and esophagus, particularly when compared to a larger ELS, then simultaneous bilateral thoracoscopic surgery should be carried out.

Based on the designed surgical plan, we performed the following procedure. The child was positioned on the left side and underwent single-lumen tracheal intubation, involving the selective occlusion of the right main bronchus with a bronchial occluder. A closed chest was established, maintaining artificial pneumothorax at a pressure of 6–8 mmHg (1 mmHg = 0.133 kPa) and a flow rate of 1 L/min. We used the three-hole method and 30° thoracoscopy, with the observation hole positioned in the 8th intercostal space of the subscapular angle line, and the two operating holes situated in the 9th intercostal space of the midaxillary line and the 8th intercostal space of the anterior axillary line (Fig. 2A). The forceps were used to gently pull and compress the lungs, rendering the boundary between the lesion and normal lung tissue visible, and LigaSure was used to wedge resect along the boundary (Fig. 2B). Separating the space between the descending aorta and esophagus along the connecting tissue between the ILS and ELS, we smoothly pulled the left ELS into the right chest cavity. After liberating the abnormal supply artery of the common trunk, we ligated it with ligation clip vertically and severed it by LigaSure, concurrently resecting the ILS and ELS (Fig. 2C, D). A retrieval bag was used to remove the lesion, which was then sent for pathological examination (Fig. 3A). No active bleeding or air leakage was observed, and the lungs expanded well. A chest drainage tube was then inserted in the right chest cavity. The patient’s postoperative vital signs remained stable. On the 4th day post-surgery, X ray showed that bilateral lung expansion was well, with no pleural effusion or pneumothorax (Fig. 3B). The closed thoracic drainage tube was removed and discharged on the 6th day post-surgery.

Fig. 2

In thoracoscopy: (A) A three-hole method incision; (B) clear boundary between the ILS and the normal lung tissue; (C) gap between ILS and ELS situated between the descending thoracic aorta and the esophagus; and (D) left ELS connected with the right ILS. Free the common trunk of the abnormal supply artery. ( ◆: Intra-lobar pulmonary sequestration (ILS), ★: Extra-lobar lung sequestration (ELS), ●: Aorta artery, ▲: Common trunk of the abnormal supply arteries, ■: Esophagus, ▍: The gap on the mediastinal pleura)

Fig. 3

Pathological macroscopic view, postoperative X ray before the closed thoracic drainage tube removed and postoperative chest CT after one month: (A) Macroscopic view of connected bilateral the ILS and the ELS, which are connected by tissues. (B) Bilateral lung expansion was well, with no pleural effusion or pneumothorax. (C) Absence of residual lesions in both lungs and no residual cavities in both chest cavities. ( ◆: Intra-lobar pulmonary sequestration (ILS), ★: Extra-lobar lung sequestration (ELS))

The outcome pleased the girl. A follow-up chest CT scan three-month post-surgery showed no residual lesions or cavities in either the lung or chest cavity (Fig. 3C).

Discussion and conclusions

PS is a rare congenital lung malformation initially defined by Pryce in 1946 as non-functional lung tissue separated from a normal tracheobronchial tree and supplied by an abnormal systemic blood supply [8]. PS is categorized into ILS and ELS. ILS represents an abnormal area within normal lung tissue lacking its own pleural coverage, whereas ELS is separated from normal lung tissue and possesses its own pleural coverage. PS is typically nourished by abnormal arteries originating from the descending thoracic, abdominal aorta, intercostal artery, common celiac trunk, left gastric artery or left renal artery. The ILS vein usually returns to the pulmonary vein, whereas the ELS vein generally returns to the systemic vein, azygos vein system, or pulmonary vein [9, 10].

Despite being a benign lesion, PS leads to diverse potential complications, including recurrent lung infections, hemoptysis, congestive heart failure, and tumorigenesis. It may be severe enough to require intubation in neonates [11,12,13]. ILS, given its connection with adjacent lung tissues, often results in recurrent lung infections. Although ELS is isolated from normal lung tissue, it still poses a risk of malignant transformation or considerable spontaneous bleeding [12, 13]. Consequently, early surgical resection is the primary treatment, even for asymptomatic patients with PS.

Thoracotomy is the conventional surgical approach for PS treatment. With the advancement of minimally invasive technology, thoracoscopy has become feasible, resulting in favorable surgical outcomes with few cases necessitating conversion to thoracotomy [6, 14]. ELS requires independent resection, whereas various surgical options are available for ILS, which is situated within the lung tissue. Lobectomy is the primary surgical method for treating ILS. In asymptomatic cases of ILS, wedge or segmental resection can be used to preserve the lung parenchyma [15]. Owing to the complex and diverse supply and return vessels of PS, preoperative evaluation is crucial to prevent major bleeding caused by vascular rupture during surgery. Currently, enhanced CT is recognized as an effective evaluation method. This imaging technique not only allows determination of the number, location, and route of blood vessel supply and return but also facilitates the distinction between ILS and ELS, identification of inflammatory lesions, and assessment of the clarity of boundaries with normal lung tissue. These findings provide a reference for the design of surgical plans [8].

We identified five patients with bilateral ILS and ELS, including three children through a literature review (Table 1) [3,4,5,6,7]. All five patients had right ILS and left ELS. Among them, four cases presented abnormal supply arteries originating from the descending thoracic aorta, of which three cases had a common trunk and one had a common celiac trunk. Additionally, two cases showed common venous reflux, one in the azygos vein system and one in the portal vein. Three patients underwent staged bilateral thoracotomy, while two patients underwent simultaneous bilateral thoracoscopic surgery. However, these methods require entry into both sides of the chest cavity, which not only delayed postoperative recovery but also affected the aesthetics of incision scars on both sides of the chest walls. Therefore, simultaneous unilateral thoracoscopic resection is considered the ideal surgical approach.

Table 1 Bilateral ILS and ELS in the literature

Our article reports a case of bilateral ILS and ELS with two anatomical characteristics: first, a tissue connection between the right ILS and left ELS; second, the supply and return vessels of the ILS and ELS are both common trunks. Given the connection, the left ELS can be pulled into the right chest cavity through the gap between the descending thoracic aorta and the esophagus. With the abnormal supply artery common trunk and the ELS reflux vein flowing into the right pulmonary vein, cutting off the abnormal common trunk artery eliminates the vascular connection between the left ELS and left chest cavity, removing the risk of vascular rupture during separation. This ensures a smooth transition of the left ELS to the right chest cavity. We applied this surgical design and successfully utilized simultaneous unilateral thoracoscopy to resect the bilateral ILS and ELS.

PS has various vascular connections, and bilateral ILS and ELS may involve common trunks of abnormal supply and return vessels. By combining clinical characteristics of the patient with enhanced CT, a comprehensive preoperative surgical plan can be developed. Simultaneous unilateral thoracoscopic resection of bilateral ILS and ELS is feasible and effective.