Recognizing and Managing Post-Lobectomy Lung Torsion: A Critical Case Report

Introduction

Lung torsion is a rare lung postoperative complication characterized by rotation of the lung parenchyma around the bronchovascular axis. It is most often secondary to thoracic surgery, but also has other causes, including thoracic or abdominal trauma and spontaneous etiology (such as pneumothorax, pleural effusion, lobar atelectasis, pulmonary sequestration, and diaphragmatic hernia) [1]. According to research statistics, the incidence of postoperative lung torsion is 0.089% to 0.2%, with a mortality of 8.3%, mostly involving the right middle lobe of the lung after right upper lobectomy [2,3]. There are some nonspecific clinical symptoms, such as dyspnea, fever, chest pain, cough, hypoxia, atrial fibrillation, hemoptysis, and so on. However, lung torsion exhibits no specific clinical symptoms or physical signs, which greatly increases the difficulty of early diagnosis. Laboratory tests may sometimes reveal leukocytosis, but not always [4]. Therefore, lung torsion is usually diagnosed by imaging examination. The most traditional and classic method for diagnosing lung torsion is chest X-ray and computed tomography (CT), which can be supplemented by bronchoscopy if conditions permit [1]. After lung torsion occurs, serial chest X-rays usually can show progressive lung opacification, particularly if pulmonary infection is present [5]. Bronchoscopy often reveals typical bronchial stenosis or occlusion, but this is not always present, so further CT examination is required to confirm the occurrence of lung torsion [2]. A CT examination may detect bronchial and arterial stenosis or occlusion, atelectasis, lung lobe opacity, and the antler sign which refers to the abnormal curvature of the main pulmonary artery and branch vessels that appear to originate from one side rather than appearing as normally distributed dendrites [6,7]. In addition, chest-enhanced CT can clearly show sudden truncation, obstruction, and distal filling defects of the pulmonary artery [7]. Three-dimensional reconstruction of CT images can also more clearly show the stenosis, obstruction, and torsion of the bronchovascular bundle [6]. When lung torsion is diagnosed, emergency surgery is generally required. Normal lung function can be restored after the lung is returned to its normal anatomical position and sutured and fixed to the surrounding tissue, within a few hours after the torsion is resolved [8–10]. If the degree of torsion is slight, conservative treatment can also be selected [11]. Otherwise, a lobectomy is required to ensure life safety and to prevent inflammatory mediators, which have accumulated during the torsion process, from leaking into other parts of the body and causing multiple organ failure [8–10].

Although the incidence of lung torsion is very low, especially lung torsion of the left lower lobe following left upper lobectomy (only 11 cases have been reported in the past; see Table 1), its mortality rate is extremely high if it is not recognized and diagnosed in time. Among these 11 cases of left lower lobe torsion, 1 patient who underwent direct resection and 1 patient who underwent indirect resection died [12,13], while 4 patients who underwent direct resection, 2 patients who underwent indirect resection, 2 patients who underwent detorsion, and 1 patient who underwent conservative treatment survived [2,8,11,14–19]. Given that the diagnosis of lung torsion is extremely dependent on imaging examinations, it is crucial to understand and master the typical imaging features of lung torsion. Here, we report a case of a 63-year-old woman with lung torsion of the left lower lobe following left upper lobe resection for lung neoplasms, who required emergency completion pneumonectomy.

Case Report

A 63-year-old woman visited the Department of Thoracic Surgery due to a chest CT result that revealed a mixed-density mass in the left upper lobe of the lung. She had no clinical symptoms or physical signs. After ruling out distant metastasis, a thoracoscopic left upper lobectomy of the lung was performed. Perioperative findings revealed normal anatomy with clear fissures. The inferior pulmonary ligament was partially released to allow the left lower lobe to fill the left hemithorax. The operation went smoothly and the patient was safely returned to the ward. Then, routine care and supportive treatment were provided, such as 24-hour electrocardiogram monitoring, oxygen inhalation, sedation, analgesia, and nutritional support.

On the first postoperative day, the patient only felt pain around the wound, and showed a slightly increased white blood cell count. A bedside chest X-ray was performed, and the results showed that most of the left hemithorax was turbid (Figure 1A). We preliminarily speculated that the cause might be atelectasis or lung infection. We adopted conservative treatment and empirically administered antibiotics. The patient was given sputum suction and encouraged to cough and expectorate to expel endotracheal secretions, thereby promoting lung re-expansion. On the second postoperative day, the pain and white blood cell count were almost similar to the first postoperative day, so the treatment and care given were roughly the same as before. On the third postoperative day, the pain was significantly worse and affecting a larger area than before, accompanied by chest tightness, atrial fibrillation, and tachycardia, but no dyspnea. Then an urgent contrast-enhanced chest CT was performed, and the results revealed diffuse ground-glass attenuation in the left lower lobe, left lower bronchial obstruction, and an upward-twisted left inferior pulmonary artery with distal poor filling (Figure 1B–1D). Subsequently, a bedside electronic bronchoscopy found that the stump of the left upper lobe bronchus was intact, but the left lower lobe bronchus was obviously narrowed and almost completely occluded.

Due to high suspicion of left lower lobe torsion of the lung, the patient was urgently taken to the operating room. During the operation, we found that the left lower lobe was rotated 180° counterclockwise, was hard, and was black-brown-red (Figure 2A), which indicated severe pulmonary infarction. After evaluating that the lung vitality was poor, a left lower lobectomy of the lung was performed. The pathological results also showed that the arteries, veins, and capillaries in the left lower lobe were dilated and congested, and the surrounding alveolar spaces were expanded, and filled with a large number of red blood cells and some lymphocytes and neutrophils (Figure 2B). Postoperative care was provided according to the postoperative care standards of pneumonectomy. Fortunately, the patient recovered well after the operation. A chest X-ray on the tenth day (Figure 2C) showed a normal imaging phenomenon after pneumonectomy of the left lung. Then the patient was successfully discharged. The follow-up chest X-ray after half a month (Figure 2D) was similar to that on the tenth day, without any complications.

Discussion

Although lung torsion, a rare but seriously life-threatening pulmonary complication, has no specific clinical symptoms and signs, it can be diagnosed by chest X-ray, chest CT, and bronchoscopy [1]. Therefore, paying attention to chest imaging changes after pulmonary surgery and improving awareness of lung torsion are the keys to saving torsional lung function.

Here, we describe a case of left lower lobe torsion after left upper lobectomy. Previous studies have shown that the most common clinical symptoms of lung torsion are dyspnea, fever, and chest pain [3]. In this case, the patient developed clinical symptoms of progressive chest pain and leukocytosis after left upper lobectomy, accompanied by atrial fibrillation and tachycardia, but no fever, dyspnea, or hypoxia. Among the 11 cases of left lower lobe torsion after left upper lobe resection, the symptoms of each patient were different, but they were mainly concentrated in the realm of respiratory and cardiovascular system symptoms [2,8,11–19]. The non-specificity of its clinical symptoms is affected by many factors, such as the duration of the torsion, the degree of torsion, and individual differences. Lung torsion is very rare and the number of cases is currently small. Therefore, the conclusions obtained from limited data analysis have certain reference value, but there are still complex factors such as data publication bias, poor data integrity, and differences in genetic background [3]. Therefore, more cases are needed in the future to further explore whether there are specific symptoms and signs of lung torsion.

Previous studies [3,20] have shown that the main causes of postoperative lung torsion include: incomplete development of pulmonary fissures, excessive release of the pulmonary fissure and inferior pulmonary ligament during surgery, longer pulmonary pedicles of the remaining lung, and enlarged intrathoracic cavity after surgery. These conditions lead to increased lung mobility, especially torsionability. Meanwhile, pneumonia and bronchial obstruction lead to atelectasis and consolidation, and uneven gravity distribution increases the probability of lung torsion. Lung torsion can also be brought about by excessive flipping of the lung lobe during surgery, poor reduction before chest closure, lack of visual field exposure during chest closure, and insufficient lung expansion. During the operation performing the left upper lobectomy described here, it was observed that the patient had clear pulmonary fissures and the inferior pulmonary ligament had been partially released to allow filling of the left chest cavity as much as possible. In addition, the left chest cavity was larger after the left upper lung resection. These may be the reasons for the patient’s lung torsion of the left lower lobe. Therefore, it seems reasonable to take certain precautions after left upper lung resection. In patients with long pulmonary pedicles and fully developed fissures, the lung can be sutured to adjacent thoracic tissues such as the pericardial fat pad or pleura [21]. Medical adhesive can be used when the lung is fully inflated and with no potential for torsion [22,23]. In addition, preservation of the inferior pulmonary ligaments can potentially prevent lung torsion [24].

During the diagnosis and treatment in this case, the chest X-ray on the first day after surgery showed turbidity in the left lower lung, and we initially considered this to be a lung infection or atelectasis. On the third day after surgery, after the symptoms significantly worsened, an emergency chest-enhanced CT and bronchoscopy were performed. After multidisciplinary consultation, lung torsion of the left lower lobe was highly suspected. The subsequent emergency surgery also confirmed the diagnosis. Fortunately, the patient eventually recovered after left lower lung resection, and no complications occurred during follow-up. In this case, the lung torsion of the left lower lobe was not diagnosed initially, and there was misdiagnosis and delayed diagnosis. The reason was largely related to the non-specific symptoms of lung torsion and the lack of understanding of lung torsion by the clinical physicians. It has been reported that the misdiagnosis rate of lung torsion is about 18.3%, and the average diagnosis time is 4 days [3]. In addition, postoperative lung torsion can easily be confused with pulmonary complications such as hemothorax, atelectasis, and pulmonary infection [1]. Therefore, when the above diseases cannot be ruled out and the patient’s condition gradually worsens, further chest CT and bronchoscopy are required to assist in confirming the diagnosis. If conditions permit, chest-enhanced CT and CT three-dimensional reconstruction can also be considered as ways to observe changes in the bronchi and pulmonary vessels.

Conclusions

This report has highlighted the importance of postoperative imaging following left upper lobectomy, because although left lower lobe torsion is a rare complication, it is a potentially life-threatening condition that requires emergency pneumonectomy.