Endoluminal approaches to postoperative air leaks.

Postoperative air leaks occur in up to 50% of patients following pulmonary resection, with 8-10% progressing to prolonged air leak (PAL) beyond postoperative day 5. PAL is associated with increased risk of empyema, reoperation, readmission, and prolonged hospitalization, imposing a substantial clinical and economic burden. This chapter provides a comprehensive review of the pathophysiology, risk stratification, diagnostic evaluation, and contemporary endoluminal treatment options for postoperative air leaks. Several preoperative prediction models-including the index of persistent air leak (IPAL), the prolonged air leak score (PALS), and the Gilbert score-have been developed to identify high-risk patients, though discriminatory performance remains moderate and no model-guided strategy has been shown to improve outcomes. Postoperative air leaks are classified temporally, physiologically as drainage-dependent PAL (DDPAL) or drainage-independent PAL (DIPAL), and by severity using analog or digital grading systems. Digital chest drainage systems offer objective airflow quantification and modestly reduce chest tube duration and hospital length of stay (LOS) compared with analog systems, though validated intervention thresholds are lacking. Accurate localization of the air leak source-distinguishing bronchopleural fistula (BPF) from alveolar-pleural fistula-is essential for guiding intervention. Sequential bronchoscopic balloon occlusion remains the most practical localization technique, while surgical methods including indocyanine green (ICG) fluorescence imaging offer complementary approaches. Endoluminal therapies encompass three mechanistic categories: one-way endobronchial valves (EBVs), bronchial occlusion devices (Watanabe spigots), and sealants [fibrin glue, cyanoacrylate, polyethylene glycol (PEG)-based hydrogel], supplemented by autologous blood patch (ABP) therapy. EBVs represent the most extensively studied modality, with a pooled success rate of 82% across 2,472 patients, though evidence is limited to observational studies. Emerging bioengineered approaches-including silk-elastin sponges, bio-three-dimensional (3D) printed cellular plugs, and lung-mimetic hydrofoam sealants-remain preclinical. With careful patient selection, physiologic classification, and appropriate device matching, endoluminal therapies offer minimally invasive alternatives that may reduce morbidity in patients with persistent postoperative air leaks who are not candidates for surgical re-exploration.