Management of bronchopleural fistula with endobronchial valve in hybrid operating room following transbronchial microwave ablation

Abstract

Transbronchial microwave ablation for the treatment of lung nodules is gaining popularity. In the present case, transbronchial microwave ablation to a right middle lobe lesion was performed under electromagnetic navigation bronchoscopy guidance. It was complicated with pneumothorax and persistent air leak despite chest drainage and chemical pleurodesis. A diagnosis of bronchopleural fistula was reached and an endobronchial valve was implanted to the middle lobe segmental bronchus with almost immediate cessation of air leak. Our case demonstrated that endobronchial valve is safe and effective in managing bronchopleural fistula after transbronchial microwave ablation.

Microwave ablation is a valuable option for treating early-stage lung cancers [1].

INTRODUCTION

Microwave ablation is a valuable option for treating early-stage lung cancers [1]. Bronchopleural fistula (BPF) with persistent air leak is a well-recognized complication occurring in up to 0.6% of percutaneous thermal ablation cases [2]. Recently, transbronchial microwave ablation has been pioneered in our institute. We have encountered a case of post-ablation BPF with persistent air leak, successfully managed with endobronchial valve implantation.

CASE DESCRIPTION

An 81-year-old gentleman presented with incidental finding of a 2.1-cm right middle lobe (RML) ground glass opacity with spiculated margin on computed tomography (CT) scan. CT-guided biopsy revealed suspicious cells. After discussion in multi-disciplinary meeting, patient declined RML lobectomy and stereotactic radiation therapy and opted for transbronchial microwave ablation.

In the hybrid operating room under fluoroscopy and cone-beam CT (CBCT) guidance, navigation to the RML ground glass opacity was performed with electromagnetic navigation bronchoscopy. The edge of the lesion was 2 mm from pleural surface. After confirmation of lesion puncture by CBCT, the locatable guide was exchanged to Emprint™ Ablation Catheter (Covidien™, USA), such that the tip of catheter was 3 mm from pleura. Microwave ablation was effected with 100 W for 10 min. The post-ablation CBCT showed adequate ablation zone covering the initial lesion with adequate margins (Fig. 1). However, postoperative chest X-ray showed right pneumothorax and a chest drain was inserted. While waiting for CT scan, talc pleurodesis was performed for moderate persistent air leak on post-ablation day 9, but to no avail. CT scan on post-ablation day 13 showed residual pneumothorax and a BPF through ablated lung (Fig. 2).

Figure 1:

(A) Pre-ablation planning. The ablation catheter punctures the target lesion, which is represented by orange tracings, while the predicted ablation zone was marked by the blue and red ovals. (B) Computed tomography scan after ablation showing the ablation zone represented by ground glass opacities.

Figure 2:

Postoperative computed tomography demonstrating ablation zone (ground glass opacity with central air bronchogram) and bronchopleural fistula.

We decided for endobronchial valve implantation on post-ablation day 18 in view of persistent air leak. Intraoperatively, blocking of the RML lateral segmental bronchus with a 3-Fr embolectomy balloon led to a drop in air leak on digital chest drain monitor from 140 to 0–40 ml/min. A Zephyr^® 4.0 endobronchial valve (Pulmonx Corp., Redwood City, CA, USA) was inserted to RML lateral segmental bronchus with good fit.

No air leak was noted thereafter, chest drain was removed 2 days later and patient was discharged. The endobronchial valve was removed with bronchoscope 6 weeks after implantation. CT scan after removal showed a healed fistula tract.

DISCUSSION

Microwave ablation as loco-regional treatment for lung cancer is rapidly evolving. Although being a minimally invasive procedure, complications, including pain, pneumothorax (11–52% risk), pleural effusion and infection, have been reported in previous case series on percutaneous microwave ablation [3]. BPF with persistent air leak is a rare but exasperating complication and can lead to prolonged hospital stay, pneumonia or even mortality. Transbronchial microwave ablation attempts to reduce pleural-based complications by avoiding trans-pleural puncture. In our series of 58 transbronchial microwave ablations, there were only 4 (6.9%) cases of pneumothorax including 1 case of BPF (present case) [4]. Successful treatment of BPF with endobronchial valves after percutaneous microwave ablation has been reported previously [5]. Endobronchial valves selectively block inspiratory airflow while allowing expiratory airflow, thus collapsing the portion of lung supplied by that bronchus and permitting fistula tracts to heal. In transbronchial microwave ablation, the initial lesion is likely accessible via a segmental bronchus (presence of ‘bronchus sign’ for easy electromagnetic navigation bronchoscopy navigation), thus blocking one segmental airway is likely to be sufficient. In contrast, the target lung lesion may be located in cross-ventilation zone in percutaneously ablated cases, potentially requiring blockage to more than one segmental bronchus to stop air leak. It is important to note that CT scan to rule out BPF should be performed prior to talc pleurodesis in ideal situation to avoid the risk of empyema.

CONCLUSIONS

This case demonstrated that endobronchial valve is a simple, safe and effective way to manage BPF after transbronchial microwave ablation.

Funding

This work was supported by Research Grants Council (RGC) University Grant Committee Hong Kong (Grant No 14119019).

Conflict of interest: Calvin S.H. Ng and Rainbow W.H. Lau are consultants for Medtronic and Siemens Healthineer. Other authors have no potential conflicts of interest.

Reviewer information

Interactive CardioVascular and Thoracic Surgery thanks Antonio Alvarez and the other, anonymous reviewer(s) for their contribution to the peer review process of this article.