Complications after lung surgery: CT evaluation

Transcription

1 Complications after lung surgery: CT evaluation Poster No.: C-0855 Congress: ECR 2010 Type: Educational Exhibit Topic: Chest Authors: A. Roque Perez, O. Persiva Morenza, D. Varona Porres, E. Pallisa Nuñez, J. Andreu Soriano, S. Mecho Meca, J. Caceres Sirgo; Barcelona/ES Keywords: Computed Tomography, Lung surgery, Postsurgical complications DOI: /ecr2010/C-0855 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 20

2 Learning objectives To review the early and late complications following lung surgery and the CT appearance of these surgery-related complications. Background A variety of surgical procedures are currently used in the treatment of lung diseases. None of these techniques is free of postsurgical complications, which differ according to the type of surgery and the time elapsed since surgery was performed. CT scans obtained in patients who have undergone lung surgery show normal alterations resulting of the surgical procedure as well as various possible postsurgical complications. Imaging findings OR Procedure details Pulmonary resection techniques Resection of the lungs may vary from minimal incision of the visceral pleura and enucleation of a lung nodule to a pneumonectomy. According to the extension of the removed lung parenchyma, one can classify pulmonary resection techniques in three main types: pneumonectomy (when an entire lung is removed), lobectomy (a pulmonary lobe) and limited resections. These procedures may be extended to include excision of a part of the chest wall, pleura, pericardium, diaphragm, esophagus and vascular structures. Pneumonectomy - Intrapleural (resection of the lung + visceral pleura). This is the most used procedure - Extrapleural (ipsilateral lung + parietal pleura + mediastinal pleura + pericardium + diaphragm) - Intrapericardial Page 2 of 20

3 - Sleeve pneumonectomy (lung + tracheobronchial angle/ carina / lower trachea) Lobectomy - Lobectomy - Bilobectomy - Sleeve lobectomy (portion of a main bronchus + involved lobar bronchus + associated lung tissue) Limited resection - Segmentectomy - Wedge resection - Enucleation - Blebectomy or bullectomy - Nonanatomic resections (including lung volume reduction surgery) Normal postsurgical changes Initial changes in patients who have undergone pneumonectomy include a midline positioned or minimum shifted mediastinum towards the pneumonectomy side and the presence of air within the postsurgical cavity (fig. 1). The postpneumonectomy cavity gradually fills with fluid (fig. 2) and, after the first week, approximately it fills half of the space. The mediastinum gradually shifts towards the postpneumonectomy space as a Page 3 of 20

4 result of hyperinflation of the contralateral lung and reabsorption of gas and fluid at the postsurgical cavity. Fig.: 1. Normal postoperative changes in a 43-year-old pacient who underwent right pneumonectomy for squamous cell carcinoma of the lung. CT shows air-fluid level in the postpneumonectomy space, with discrete mediastinal shifting. Page 4 of 20

5 Fig.: 2. Same pacient, three months later. Postpneumonectomy space is smaller and completely filled with fluid, with increase in the degree of mediastinal shifting. The degree of mediastinal shifting depends on the distensibility of the contralateral lung (fig. 3, fig. 4). The fluid may reabsorb completely, organize or persist for years after surgery. Fig.: 3. Normal evolution of a right pneumonectomy, with a small remaining postpneumonectomy space and shifting of the mediastinum towards the surgical side. Page 5 of 20

6 Fig.: 4. Normal evolution of a left pneumonectomy. CT shows important volume loss of the left hemithorax, with a very important shifting of mediastinal structures. When a lobectomy is performed, postsurgical changes include lung volume loss and the presence of fluid collections within the surgical bed (fig. 5). Fig.: year-old woman with operated colon cancer and pulmonary metastases who had undergone right upper lobectomy. CT on the first postoperative days (a, b) Page 6 of 20

7 shows a small fluid collection adjacent to the suture line (arrow) and a small amount of pneumothorax and pneumomediastinum (arrowheads). These findings had resolved in a follow-up CT performed 5 moths later. Complications of pulmonary resection (table 1, table 2) Intraoperative complications - Injury to a major pulmonary vessel - Cardiac complications (cardiac arrhythmias, myocardial ischemia) - Contralateral pneumothorax Postoperative complications - Early complications - Late complications Page 7 of 20

8 Fig. Fig. Page 8 of 20

9 Atelectasis Atelectasis is the most frequent complication after thoracic surgery. It results from retained secretions or from surfactant alterations, and can occur in the operated lung or in the contralateral one. CT findings are segmental, lobar or lung collapse and increased opacity in the atelectatic lung parenchyma (fig. 6). Infection may be superimposed on atelectatic areas in some patients. Fig.: 6. Postoperative CT scan of a pacient who had undergone right apical bullectomy, showing right inferior lobe subsegmental atelectasis (arrows) Pneumonia The most common causes of postoperative pneumonia are aspiration of gastric secretions and bacterial colonization of atelectatic lung. It is more common in intubated patients and those requiring mechanical ventilation. CT findings (fig. 7) include: parenchymal consolidation (frequently with air bronchograms) centrilobular nodules peribronchial thickening ground-glass opacities cavitation pleural effusion Page 9 of 20

10 Fig.: year-old woman who underwent right superior lobectomy for squamous cell carcinoma and developed postoperative pneumonia in the right inferior lobe. CT scan shows pulmonary consolidation with air bronchograms and ground-glass opacities. Hemothorax Hemothorax often manifests as a rapidly enlarging pleural effusion. CT shows heterogeneous pleural fluid with hyperattenuating areas and a fluid-hematocrit level, with adjacent relaxation atelectasis. As the hemorrhagic pleural effusion begins to clot, loculations may develop within the pleural fluid. Although hemothorax usually appears in the early postsurgical stage, it can be seen as a late complication (fig. 8). Page 10 of 20

11 Fig.: 8. Late-onset hemothorax in a left pneumonectomy. Note hyperattenuating areas in the postpneumonectomy space fluid (arrows), better seen if we adjust window levels. Chylothorax Accumulation of chyle in the pleural space is caused by rupture of the thoracic duct or one of its major divisions during surgery. A rapid filling of the postpneumonectomy space with high triglyceride concentration fluid is considered diagnostic. CT shows pleural effusion with variable attenuation levels depending of the proportion of fat and proteic content of the fluid. Pulmonary edema The cause of this life-threatening complication remains undetermined. Contributing factors probably are increased hydrostatic pressure and altered permeability of capillaries. Postpneumonectomy edema is diagnosed by exclusion, and occurs more commonly after right pneumonectomy. The most frequent radiological findings include peribronchial and interlobular septal thickening and pulmonary opacities. Cardiac herniation Page 11 of 20

12 This is a very rare postsurgical complication, with high mortality rates, and it requires urgent reduction. It is caused by prolapse of the heart through a pericardial defect (fig. 9) created for surgical exposure of the hilar vessels of the lung, and usually has an immediate postsurgical onset within 24 hours after pneumonectomy. Fig.: 9. Cardiac herniation. 53-year-old patient with left superior lobe squamous cell carcinoma whith invasion of the pulmonary artery. After neoadjuvant chemotherapy, he underwent intrapericardial pneumonectomy and mediastinic lymphadenectomy. The 3rd postoperative day he developed dyspnea, hypoxemia and right bundle branch block. Under the suspect of pulmonary embolism, a chest CT angiography was performed. CT ruled out pulmonary embolism, showing marked lateral angulation of the heart, with the cardiac apex touching the posterolateral chest wall, as well as important pleural effusion. Lung torsion Postoperative lung torsion is caused by torsion of hilar structures, especially of the pulmonary veins, leading to impaired circulation with venous reflux resulting in interstitial edema and alveolar exudation. This postsurgical complication has a rapid progression with deterioration of the pacient, so its early recognition is vital. CT findings include: tapered obliteration of the proximal pulmonary artery and accompanying bronchus of the involved lobe ill-defined soft-tissue attenuation a the hilum the torsed lobe shows poorly enhancing consolidation, increased volume, ground-glass opacities and interlobular and intralobular septal thickening. Page 12 of 20

13 Anastomotic dehiscence and stricture Extended resections and extended lymph node dissections may increase the risk of bronquial wall ischemia or excessive tension on the bronchial suture line, leading to anastomotic dehiscence or stricture. Anastomotic dehiscence may manifest as an early complication and may lead to bronchopleural fistula. The most important findings in anastomotic dehiscence are the presence of a defect in the bronchial wall and extraluminal air surronding the anastomosis, while anastomotic strictures are seen as bronchial narrowing and irregularity (fig. 10, fig. 11). Fig.: 10. Follow-up CT in a patient with bilateral lung transplantation and dehiscence of the left bronchial suture (arrow) showing a defect in the bronchial wall and adjacent extraluminal air. Page 13 of 20

14 Fig.: 11. Follow-up CT in a pacient with alfa-1-antitrypsin deficiency and bilateral lung transplantation. There is right main bronchial stenosis (a, arrow) and dehiscence of the left bronchial suture (b, arrowhead), better seen in a minip coronal view (c). Bronchopleural fistula This is a potentially fatal complication of lung surgery. The most common cause of death associated with this condition is aspiration pneumonia with subsequent adult respiratory distress syndrome. Bronchopleural fistula is more common after right pneumonectomy due to anatomic features of the right main bronchus (larger size, greater tendency to spring open and less mediastinal coverage than the left bronchus). Early bronchopleural fistulas are usually due to faulty closure of the bronchus. Delayed bronchial leaks are much more common, and are usually due to infection or recurrent tumor of the bronchial stump. Radiological findings consist of: continuous increase in the residual intrapleural space appearance of an air-fluid level changes in an already present air-fluid level development of tension pneumothorax CT findings include air and fluid collections in the pleural space and demonstration of a communication or tract from an airway or the lung parenchyma to the pleural space (fig. 12, fig. 13). Page 14 of 20

15 Fig.: year-old patient with left pneumonectomy for lung carcinoma and chronic bronchopleural fistula. Coronal minip reformation (a), axial view (b) and virtual endoscopy (c) show the communication tract (arrow) between the left main bronchus and the postneumonectomy space, with a Foley catheter in the cavity. Fig.: 13. Another case of bronchopleural fistula. Note the communication tract between the right main bronchus and the postpneumonectomy space and the communication between the cavity and the exterior. Page 15 of 20

16 Empyema Postpneumonectomy empyema is an uncommon complication associated with high mortality rates. It usually occurs in the early postoperative period, but may develop moths or even years after surgery. Postpneumonectomy empyema manifests as multiple air-fluid levels in the early postoperative period and as a volume-expanding process within the postpneumonecomy space in the late postoperative period. CT shows reversal of the normal concavity of the mediastinum even without mediastinal displacement (fig. 14), sometimes accompanied with thickening of the residual parietal pleura and bronchopleural or esophagopleural fistula. Fig.: 14. Postpneumonectomy empyema (b) in a patient who developed fever after undergoing left pneumonectomy. CT scan showed reversal of the normal concavity of the mediastinal pleura. Postpneumonectomy syndrome Page 16 of 20

17 Postpneumonectomy syndrome consists of compression of the intrathoracic airways of the remaining lung against fixed mediastinal structures, and it results from an exaggerated response to some pulmonary compensatory mechanisms after pulmonary resection. CT images show abnormal narrowing of the airway caused by compression between mediastinal structures. Recurrence of local tumor CT images depict tumor recurrence as a soft-tissue mass near the bronchial stump and helps detection of abnormalitites such as pleural seeding and involvement of mediastinal limph nodes (fig. 15). Fig.: 15. Tumor recurrence in a pacient who underwent left pneumonectomy for squamous cell carcinoma of the lung. CT depicts soft-tissue masses within the postpneumonectomy space. Other complications Page 17 of 20

18 Other complications of lung surgery that may occur in the early or late postoperative periods include wound infection (fig. 16), pulmonary artery stump thrombosis (fig. 17) and iatrogenic complications (fig. 18). Fig.: 16. Wound infection in a 62-year-old man with usual interstitial pneumonia who underwent left lung transplantation and developed fever. Postoperative CT shows fluid collections (arrows) adjacent to the sternal wound (arrowhead). Fig.: 17. Axial view (a) and oblique sagital view (b) of left pulmonary artery stump thrombosis in a 73-year-old patient who had undergone left inferior lobectomy for lung cancer. Six months later he developed right pulmonary embolism (c). Page 18 of 20

19 Fig.: 18. Intrapulmonary-placed catheter in a 48-year-old patient with cystic fibrosis and left lung transplantation who developed chronic left pleural effusion that required pleural drainage. The catheter entered through left superior lobe and crossed the left fissure (arrow) with the distal end placed at the apical segment of the left inferior lobe. Note the small areas of pulmonary laceration (arrowheads) next to the catheter path. Conclusion CT provides important information regarding thoracic structures when complications are suspected after lung surgery. Personal Information References Kim EA, Lee KS, Shim YM, Kim J, Kim K, Kim TS, Yang PS. Radiographic and CT findings in complications following pulmonary resection. Radiographics 2002;22(1):67-86 Page 19 of 20

20 Nagasaki F, Flehinger BJ, Martini N. Complications of surgery in the treatment of carcinoma of the lung. Chest. 1982;82(1):25-9 Chae EJ, Seo JB, Kim SY, Do KH, Heo JN, Lee JS, Song KS, Song JW, Lim TH. Radiographic and CT findings of thoracic complications after pneumonectomy. Radiographics 2006;26(5): WechslerRJ, Goodman LR. Mediastinal position and air-fluid height pneumonectomy: the effect of the respiratory cycle. AJR 1985;145: after Bhalla M. Noncardiac thoracic surgical procedures. Definitions, indications and postoperative radiology. Radiol Clin North Am 1996;34(1): Kwek BH, Wittram C. Postpneumonectomy pulmonary artery stump thrombosis: CT features and imaging follow-up. Radiology 2005;237(1): Page 20 of 20