Abstract
Postoperative chylothorax directly resulting from thoracic duct injury is rare following pulmonary surgery. We describe a patient with suspected lung cancer undergoing thoracoscopic right upper lobe posterior segmentectomy with lobe-specific mediastinal lymph node dissection who presented with persistent chylothorax. Despite sequential conservative measures, including chylous drainage and a low-fat diet, her clinical symptoms recurred persistently. Secondary surgery confirmed a thoracic duct injury, presumably caused by improper stapler application during parenchymal transection, where the staple line over-extended and injured the adjacent duct. This unreported mechanism underscores the need for clinical vigilance against chylothorax resulting from iatrogenic stapler overextension injury.
Introduction
Video-assisted thoracoscopic surgery (VATS) has become the standard minimally invasive approach for pulmonary resection, offering distinct perioperative advantages over open thoracotomy. Chylothorax, though uncommon after VATS, is typically associated with mediastinal lymph node dissection; thoracic duct injury from stapler misuse is exceptionally rare. We present an uncommon case of chylothorax after sublobar resection with lobe-specific lymphadenectomy, in which reoperation confirmed a thoracic duct injury likely caused by improper stapler use—an unreported mechanism to date. This case highlights the need for heightened technical awareness, especially among novice VATS surgeons.
Case report
A 54-year-old female presented with a 2-month productive cough. No notable medical history, epidemic-area exposure, or familial genetic disorders were elicited. Admission vital signs were unremarkable, with a body mass index (BMI) of 21.19 kg/m2. Chest computed tomography (CT) revealed a part-solid nodule in the posterior segment of the right upper lobe, suspicious for primary lung cancer (Fig. 1). Uniportal VATS right upper lobe posterior segmentectomy and lobe-specific mediastinal lymph node dissection (stations 2, 4, and 7) were performed via a fifth-intercostal incision between the anterior and midaxillary lines. No pleural adhesions were encountered intraoperatively. Postoperative pathology confirmed a 0.6 × 0.5 cm acinar-predominant invasive adenocarcinoma of the right upper lobe, without lymphovascular, perineural, pleural, or tumor spread through air spaces involvement, and with negative bronchial margins and lymph nodes (Fig. 2). Chylous drainage (~200 mL) was noted via thoracic drain on postoperative Day 2. Conservative management with fasting, parenteral nutrition, and a low-fat diet was instituted. By postoperative week 2, drainage had decreased to 30–50 mL/day, enabling tube removal and discharge, with dietary instructions for a high-protein, low-fat regimen.
Radiological findings of the primary lesion. Chest CT revealed a part-solid nodule (arrow) in the posterior segment of the right upper lobe, suspicious for primary lung cancer.
Postoperative pathological examination revealed invasive adenocarcinoma in the nodule of the right upper lobe characterized by irregular, atypical glandular structures lined by enlarged, pleomorphic nuclei with prominent nucleoli, set within a desmoplastic (fibrous) stroma.
The patient was readmitted approximately two weeks post-discharge with chest tightness and dyspnea. Chest radiography revealed a large right-sided pleural effusion (Fig. 3). Thoracentesis yielded milky, turbid chylous fluid, with a positive chylous test. Management consisted of fasting, intravenous nutritional support, somatostatin, and multiple intermittent intrapleural 50% glucose injections over three weeks. Daily drainage output ranged from 200 to 500 mL of pale yellow fluid, with chest X-ray showing minimal residual pleural fluid and patent drainage. Surgery was deferred for three weeks due to an uncertain response and patient preference, amid stable clinical status and restored nutrition after albumin, and was performed only after conservative failure was confirmed. Whole milk (200 mL) was given orally 8 hours prior. Thoracoscopic exploration via the prior incision revealed localized adhesions between the residual right upper lobe and the right pleural apex. Adhesiolysis exposed a fistulous defect in the posterior-superior mediastinal pleura (above the azygos vein, posterior to the trachea, anterior to the thoracic vertebrae), with active chylous leakage (Fig. 4 and Supplementary Video S1). The fistula was oversewn with 4–0 PROLENE, and the lower thoracic duct was ligated with a Hemo-Lock clip. Postoperative recovery was uneventful, and no tumor or chylothorax recurrence was observed during a 5-year follow-up.
Radiographic findings: Chest radiograph showing a large amount of pleural effusion in the right hemithorax. R, right.
Site of chylous leak: a fistulous defect in the posterior-superior mediastinal pleura (above the azygos vein, posterior to the trachea, anterior to the thoracic vertebrae), with active chylous leakage.
Discussion
Iatrogenic chylothorax, a recognized complication of thoracic surgery, occurs in 0.5%–2% of radical lung cancer resections [1], lymph node dissection may jeopardize its branches [2, 3]. In this stage IA case with limited resection (segmentectomy and lobe-specific mediastinal lymph node dissection) and a low-output leak, conservative management was pursued. Diagnosis was confirmed by triglyceride and chylomicron criteria [4]. Interventional lymphangiography [5] was deferred due to the small, deep, and variable 4R-region branches. Surgical salvage for postoperative chylothorax entails thoracic duct or tributary ligation, with >90% success [6, 7]. Here, concurrent thoracoscopic ligation and fistula repair were performed via the prior incision. Preoperative cream intake or subcutaneous lipophilic dye aids leak localization. The optimal timing for the surgical management of chylothorax remains undefined. Early intervention is indicated for high-output leaks (>500 mL/day for 5–7 days) or conservative failure (>2 weeks) [8]. Herein, given the low-output drainage, stable nutritional indices, suspected 4R-station tributary injury, prior conservative success, and patient preference against reoperation, conservative therapy was prudently prolonged beyond the standard 2-week threshold.
Embryologically, the thoracic duct is a bilateral structure and hence many anatomical variations are possible, with classic configuration present in only 40%–60% of cases and duplication/multiple channels in up to 40% [9, 10]. Intraoperatively, the leak was localized superior to the azygos vein at T3, posterior to the trachea and anterior to the vertebrae. Despite the absence of lymphangiographic confirmation, the operative findings and failed conservative treatment indicated an injury to the main duct or a major tributary. Given that the prior lymphadenectomy (stations 2, 4, and 7) were anatomically distinct from this site, the iatrogenic causation was effectively ruled out. The leakage site was anatomically remote from the prior dissection field. A review of the operative technique suggested that during the uniportal VATS S2 segmentectomy through a narrow right fifth-space incision, the hyperextended metal tip of the endoscopic stapler—used to secure adequate resection margins within a confined thoracic cavity—may have inadvertently injured the parietal pleura or subjacent structures, including the thoracic duct or its major branches (Fig. 5). Since chyle is colorless and transparent, such injury would have gone unrecognized at the initial surgery. Vascular injury from stapler misuse is a recognized operator-related complication, but thoracic duct injury from an endoscopic stapler has not been previously reported. This case highlights the need for heightened awareness of subpleural and chest-wall structures during thoracoscopic surgery, especially in the learning phase.
Schematic diagram illustrating the mechanism of thoracic duct injury. The right upper lobe posterior segment was resected using an endoscopic stapler through the fifth intercostal surgical incision; the hyperextended metal tip of the endoscopic stapler injured the thoracic duct beneath the posterior mediastinal pleura. AV, azygos vein; TD, thoracic duct; RLL, right lower lobe; SCV, superior vena cava; RUL, right upper lobe; SI, surgical incision; RML, right middle lobe.
Conclusion
Thoracic duct injury during pulmonary surgery, though rare, can occur indirectly from stapler overextension during parenchymal transection, especially with anatomical variants. Surgeons should recognize this mechanism to prevent chylothorax after routine, minimally invasive lung resection.
Author contributions
Study concept and design: Baiqin Zhao; Data collection and data analysis: Tianshu Liu. Paper writing: Tianshu Liu. Manuscript review and editing: Tianshu Liu and Yiting Cai. All authors have read and approved the manuscript, agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Conflicts of interest
The authors declare no conflicts of interest.
Funding
None declared.
Informed consent
Written informed consent was obtained from the patient for publication of this case report.
