Video-assisted thoracoscopic surgery: The preferred method to manage pulmonary sequestration.

BACKGROUND: This study aims at describing the feasibility and safety of video-assisted thoracic surgery (VATS) in benign diseases such as pulmonary sequestrations (PSs) and report the surgical outcomes.
MATERIALS AND METHODS: This is a retrospective analysis of prospectively maintained data of 25 patients who were operated for PS over 7 years at a dedicated thoracic surgery centre in India. Pre-operative details, operative technique and details, post-operative details and complications were recorded and analysed.
RESULTS: There were 15 (60%) males and 10 (40%) females, with a median age of 22.28 years (range, 16-28 years). All patients had intra-lobar type of sequestration. The most commonly involved was left lower lobe (n = 15 patients, 60%) followed by the right lower lobe (n = 10 patients, 40%). The origin of blood supply was from the descending thoracic aorta in 18 patients (72%), the abdominal aorta in 5 (20%) and the coeliac trunk and the inferior phrenic artery in one patient (4%) each. All patients underwent complete lobar resection. One patient was converted because of dense hilar adhesion. The average duration of surgery was 179 min and the average blood loss was 204 ml. The median hospital stay and chest tube duration were 4 and 3 days, respectively. One patient was re-explored because of post-operative bleeding. Only one patient had an air leak for >7 days. The median follow-up was 42 months (range, 6-90 months) without any recurrence.
CONCLUSIONS: VATS is a safe, feasible and effective option for PS at experienced centres.

INTRODUCTION

Pulmonary sequestration (PS) is an uncommon congenital malformation characterised by an area of abnormal, non-functioning lung tissue, which has no connection with the tracheobronchial tree and receives its arterial supply from a systemic artery.[1] It is a Latin term which means ‘to separate’ and was introduced in medical literature by Pryce in 1964.[2] This congenital disorder presents with a variety of clinical features such as chest pain, cough, haemoptysis and recurrent pneumonia. Conventionally, it has been treated by open surgery via posterolateral thoracotomy. However, in recent times, video-assisted thoracic surgery (VATS) has been successfully applied in the management of benign lung diseases, including sequestration.[3] This report describes thoracoscopic management of 25 consecutive cases at our centre and investigates surgical and long-term outcomes.

MATERIALS AND METHODS

This is a retrospective analysis of a prospectively maintained database of patients who underwent surgery for PS by VATS at a tertiary care centre in India from March 2013 to December 2019. Institutional ethics committee approval was obtained. A total of 25 patients who underwent VATS for PS were included in the study. The diagnosis of PS was made pre-operatively by radiology, that is, finding of an anomalous systemic arterial supply of lung on a contrast-enhanced computed tomographic angiography (CECT angiography).

Evaluation

The demographic data; clinical presentation and pre-operative, intra-operative and post-operative details were recorded. All patients underwent CECT angiography [Figure 1a] of the chest as part of work-up to confirm the diagnosis and evaluate the source of abnormal systemic arterial supply and site of venous drainage, the type of PS, condition of lung parenchyma [Figure 1b] and any other abnormality. A detailed pre-anaesthetic check-up and pulmonary function test were done in all patients. Patients above the age of 40 years were also evaluated by a cardiologist to assess their cardiac status.

Figure 1

(a) Computed tomographic angiogram showing systemic arterial supply to the left lower lobe (marked by arrows), (b) preoperative contrast-enhanced computed tomographic angiography showing destroyed left lower lobe marked by arrow

Surgical details

All patients were operated under general anaesthesia. A double-lumen tube was placed under bronchoscopic guidance for lung isolation. We used the three-port anterior approach popularised by Hansen and Petersen, also known as the Copenhagen approach[4] [Figure 2].

Figure 2

Port placement for a three-port anterior approach

All patients were operated in a lateral decubitus position, close to the anterior edge of the operating table. A utility port was created just anterior to the latissimus dorsi muscle in the 4th intercostal space along a line joining the tip of the scapula and breast and used for entry into the chest cavity without spreading the ribs. A soft plastic wound retractor was placed in the utility incision to avoid wound contamination. Adhesions, where present, were taken down under vision through this port, and a thorough diagnostic exploration was done. Two additional working ports were created under vision. We used a 30° telescope and two video monitors for adequate visualisation by the entire surgical team. Special care was taken during adhesiolysis in the lower part of the chest near the inferior pulmonary ligament as most of the systemic arterial supply is encountered in this region. Careful delineation of the aberrant systemic supply was done. Care was taken to dissect the vessels close to the lung parenchyma in order to ensure that an adequate length of the vessel is available for control, should an inadvertent injury occur. It is essential to keep this in mind as sometimes the supply is trans-diaphragmatic from the abdominal aorta and avulsion with subsequent retraction of the stump can be catastrophic. After complete dissection, the aberrant vessels [Figure 3] were divided with an endoscopic stapler with a vascular cartridge. A formal VATS lobectomy was subsequently performed with individual dissection and division of all the hilar structures, that is, the pulmonary artery, the pulmonary vein and the bronchus [Figure 4]. Two chest tubes were placed – one in the apical area and the other in the basal area and connected to Thopaz™ digital negative suction device. All patients were extubated on the table, monitored overnight in the recovery room and transferred to the floor the next morning.

Figure 3

Two aberrant arteries (AA 1 and 2) arising from the descending thoracic aorta and going to the left lower lobe. (a) Anterior view, (b) posterior view

Figure 4

Completion of formal lobectomy. (a) Inter-lobar trunk ready for division, (b) dissected inferior pulmonary vein, (c) endo-stapling of the lower lobe bronchus, (d) specimen retrieval in bag

Post-operative care and follow-up

We followed the Enhanced Recovery after Surgery (ERAS®) protocol for all patients.[5] Pre-operative nutritional correction, chest physiotherapy and adequate counselling of the patients about the likely post-operative course were done. Minimal, need-based intra-operative intravenous fluids, avoidance of narcotic analgesics, measures to control post-operative nausea and vomiting, early ambulation and early oral feeding were employed as a part of the ERAS protocol. The chest tubes were removed after ensuring complete lung expansion and absence of air leak. Complications were recorded as per the thoracic morbidity and mortality system.[6] Prolonged post-operative air leak (>7 days), chest tube duration, wound infection and hospital stay were analysed. All patients were followed up in the outpatient department at weekly intervals for 4 weeks and then every 6th month for the first 2 years and then yearly for up to 5 years. A chest X-ray was done at 1 month and at all subsequent visits.

Statistical methods

Statistical testing was conducted with the IBM Statistical Package for the Social Sciences system, version 23.0 (Armonk, NY: IBM Corp., USA). Continuous variables were presented as mean ± standard deviation or median. Categorical variables were expressed as frequencies and percentages.

RESULTS

Twenty-five patients underwent VATS for PS during the study period. There were 15 (60%) males and 10 (40%) females [Table 1]. The median age at presentation was 22.28 years (range, 16–28 years). The most common presentation was cough in 16 patients (64%), dyspnoea in 6 (24%) and chest pain in 3 patients (12%). All patients had intra-lobar type of sequestration. The most commonly involved was left lower lobe (n = 15 patients, 60%) followed by the right lower lobe (n = 10 patients, 40%). The origin of blood supply was from the descending thoracic aorta in 18 patients (72%), the abdominal aorta in 5 (20%) and the coeliac trunk and the inferior phrenic artery in 1 patient (4%) each. All patients underwent complete lobar resection. Out of the 25 patients, the procedure was completed by VATS in all except one patient who required conversion due to dense adhesions in the hilar region with unclear hilar anatomy. The average duration of surgery was 179 min (161 min–196 min) and the average blood loss was 204 ml (147 ml–224 ml). The median hospital stay and chest tube duration were 4 and 3 days, respectively. One patient was re-explored because of post-operative bleeding. A diffuse ooze from the diaphragmatic surface (post-adhesiolysis) was the culprit. It was controlled by coagulation of the bleeding point using an electrocautery by VATS only. Only one patient had an air leak for >7 days. The post-operative recovery of other patients was uneventful. Histopathological examination of the resected specimen confirmed the diagnosis of sequestration in all cases. At the last follow-up, all patients were alive and healthy. The median follow-up was 42 months (range, 6–90 months).

Table 1

Demography and perioperative variables

Variable	Frequency
Male	15
Female	10
Mean age	22.28
Symptoms
Cough	16
Dyspnoea	6
Chest pain	3
Site
Left lower lobe	15
Right lower lobe	10
Surgical demographics
Descending thoracic aorta	18
Abdominal aorta	5
Celiac trunk	1
Phrenic artery	1
Average duration of surgery	179
Average blood loss	204
Mean hospital stay time	4
Mean ICD duration (days)	3
Intra-operative conversion	1
Re-exploration
Prolonged air leak	1
Median follow-up	42

ICD: Intercostal drainage

DISCUSSION

PS is an uncommon congenital malformation characterised by an area of abnormal, non-functioning lung tissue, which has no connection with the tracheobronchial tree and receives its arterial supply from a systemic artery. This abnormal lung tissue may be within the visceral pleura of a pulmonary lobe (the intra-lobar type, accounts for 75% of cases) or may have its own visceral pleura (the extra-lobar type, accounts for 25% of cases). The intra-lobar type drains into the pulmonary veins, whereas the extra-lobar type drains into the systemic veins.[7] The estimated incidence of PSs is 0.15%–6.4% of the total reported congenital anomalies in the literature.[8] In our series, all cases were of intra-lobar type.

PS is mainly reported in lower lobes, most commonly the left lower lobe followed by the right lower lobe,[9] as was the case in our study too. Intra-lobar sequestration may be asymptomatic or may present at a young age with cough, fever, chest pain or haemoptysis. The most common presentation is cough and frequent chest infections.[1011] The mean age of our patients was 22 years, and cough was the most common symptom.

Radiologically, these lesions may mimic mass lesions, cystic lesions, cavitary lesions or pneumonic lesions. Hence, they are often misdiagnosed and mismanaged and therefore require a high index of suspicion to diagnose correctly.[12] In the past, selective digital subtraction angiography was the gold standard for confirmation of diagnosis, but currently, CT angiography is the investigation of choice.[13] All our patients who were suspected of having PS underwent CT angiography. The most common arterial supply to sequestration comes from the descending thoracic aorta, followed by the abdominal aorta, celiac artery, splenic artery or phrenic artery.[8] The most common venous drainage of intra-lobar type of sequestration is into the pulmonary veins, whereas extra-lobar type often has systemic venous drainage.[11] All our patients had intra-lobar sequestration and venous drainage into the pulmonary vein.

The treatment of PS is surgical. However, controversy exists regarding the role of surgery in asymptomatic individuals. The proponents of surgical approach state that there is a high possibility of infection and hemorrhage in such cases if not operated.[14] On the other hand, all symptomatic patients require surgical management. Conventionally, it has been managed by posterolateral thoracotomy and resection of the lesion in the form of wedge resection or a formal lobectomy. The first report of VATS in the management of PS was by Watine et al. in 1994.[15] Since then, reports have emerged on the safety and feasibility of VATS in PS. Tsang et al. reported reduced morbidity with lesser pain, lower blood loss and shorter hospital stay in patients undergoing VATS as compared to open surgery.[16] Shen et al. reported VATS in 25 patients of PS without any major complications and proved the safety and feasibility of VATS in sequestration.[17] VATS was reported as a viable option for PS patients by Wang et al.[18]

VATS lobectomy for infectious diseases is challenging due to adhesions, often unclear hilar anatomy and presence of sticky nodes near the vessels in many cases. Our centre has been performing VATS as well as robotic surgery regularly for benign and malignant diseases since 2012 and has gained sufficient expertise to overcome these challenges.[319202122] None of our patients required conversion because of adhesions. In our experience, the enhanced magnified view of the entire thoracic cavity with judicious use of energy devices makes adhesiolysis easier in VATS than that in open surgery. Specialised instruments for VATS together with the availability of efficient articulating staplers have made the dissection and division of vessels safe. Careful evaluation by CT angiography helps in accurate pre-operative localisation of the aberrant arterial vessel along with the venous drainage in the majority of the cases, allowing for safe surgery via VATS even when challenging inflammatory adhesions are present. However, it cannot be overemphasised that one should have a low threshold for conversion, particularly during the early part of the learning curve to ensure a safe and complete surgery. An elective conversion should be treated as an intelligent decision, taken in the best interest of the patient and NOT a surgical defeat. Figure 5 outlines our suggested protocol for the management of PS.

Figure 5

Centre for Chest Surgery protocol for the management of pulmonary sequestration

Although the present study is the largest report from a single institution in India for VATS management of an uncommon condition like PS, the main limitations of this study are its retrospective nature, small sample size and lack of comparison with open surgery.

CONCLUSIONS

One should have a high index of suspicion for PS. CT angiography is required to confirm the diagnosis. Once diagnosed, surgical resection of the abnormal lobe is recommended. VATS is emerging as an attractive minimally invasive method to perform lobectomy in such cases. VATS lobectomy for PS should be further studied for its safety and effectiveness in a large series.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.