A Nachiappan, S Digumarthy, A Sharma, V Muse, M Lanuti, J Shepard
pleurodesis, pneumonectomy, spiral computed, thoracic radiography, thoracic surgery, tomography, trachea
A Nachiappan, S Digumarthy, A Sharma, V Muse, M Lanuti, J Shepard. An Overview of Lung Surgeries: Postoperative CT Findings and Complications. The Internet Journal of Radiology. 2009 Volume 12 Number 1.
There are various types of surgeries performed on the lungs, airways, pleura, and chest wall. As radiologists, it is imperative to understand the various surgeries, their expected post-operative imaging appearance and possible complications. The thoracic surgeries are broadly divided into two categories: open surgery and minimally invasive surgery. This article is a multi-modality review of open and minimally-invasive surgeries performed on the lung, pleura, trachea and chest wall. Computed tomography (CT) images, positron emission tomography (PET) images and radiographs, as well as intra-operative photographs and original illustrations of surgeries are provided to enhance understanding.
Thoracic surgeons perform a variety of procedures depending on the indication, extent of disease and the health of the patient. Thoracic surgery interventions can be broadly classified into open and minimally invasive procedures (Fig. 1).
Open surgery requires a thoracotomy or sternotomy, whereas a minimally invasive surgery requires the use of a thoracoscope, without the need for a thoracotomy. There are different types of surgical approaches such as partial sternotomy and neck incision for tracheal surgery, bilateral thoracosternotomy (clamshell sternotomy) for access to both lungs in metastatectomy and bilateral lung transplantation, and thoracotomy for unilateral lung surgery. Computed tomography (CT) is very useful in evaluating the post-surgical patient and in identifying complications.
Lung surgeries can be classified into non-anatomical and anatomical resections.
Non-anatomical lung surgery
Non-anatomical resection involves removal of a diseased portion of lung without complete dissection of the anatomic segment or lobe of the lung (including bronchus, pulmonary artery and pulmonary vein), and without removal of draining lymph nodes. The most commonly performed procedure is wedge resection, which involves resection of a non-anatomical “wedge” of lung (Fig. 2).
The indications for wedge resection are open lung biopsy for diffuse lung disease and pulmonary nodules, resection of metastatic nodules1, and low grade lung cancer such as bronchioloalveolar carcinoma, and as a salvage procedure for primary lung cancer. Another non-anatomical surgery is lung volume reduction surgery (LVRS) performed for severe emphysema, where the non-functional regions of both upper lobes (the maximal site of emphysema) are resected2 (Fig. 3).
Another non-anatomical surgery is bullectomy, where large bullae are resected in patients with decreased functional lung volume or patients with recurrent pneumothorax.
Anatomical lung surgery
Anatomic lung resection involves removing the diseased pulmonary segment(s), lobe(s) or lung along with the draining lymph nodes. Segmentectomy involves resection of a segment or any anatomic resection that is less than a lobe (Fig. 4).
For example, a basilar segmentectomy refers to en bloc resection of all the basal segments of a lower lobe. Indications for segmentectomy are resection of bronchiectasis, benign tumor, localized low-grade lung cancer, and metastasis3, as well as lung cancer resection when lobectomy is not feasible due to pulmonary compromise. Lobectomy is the accepted definitive surgery for resection of most lung cancers4 (Fig. 5) and involves complete anatomic lobar resection.
Pneumonectomy is the resection of an entire lung and can be divided into several types. Conventional pneumonectomy of either the left or right lung (Fig. 6) is necessary when there is proximal pulmonary arterial, pulmonary venous or bronchial involvement.
Pneumonectomy is the procedure of last resort for tumor resection due to its higher mortality rate5. Intrapericardial pneumonectomy is performed when tumor encroaches upon the hilum necessitating opening of the pericardium6 (Fig. 7).
Extrapleural pneumonectomy, which is performed in selected cases of malignant mesothelioma and tuberculous empyema, involves resection of the lung and parietal pleura. The involved portion of the ipsilateral hemidiaphragm and pericardium are resected and reconstructed with prosthetic material7 (Fig. 8).
To prevent bronchial stump dehiscence, a closure flap consisting of vascularized tissue is wrapped around the stump (Fig. 9).
Examples of closure flaps include intercostal, latissimus dorsi and pectoralis muscles, and omental and pericardial fat pads8.
Tracheal and carinal resection involves resecting a tumor or stricture in the airway, followed by reconstruction9 (Fig. 10).
Sleeve resection is performed for proximal endobronchial tumors and involves resection of a lobe and the adjacent airway “sleeve” of main bronchus or bronchus intermedius, followed by reanastomosis/ reimplantation of the remaining bronchi10 (Fig. 11).
Pleurodesis is performed for recurrent pleural effusion and recurrent pneumothorax, and involves administering a chemical substance (e.g. talc) via poudrage, or mechanically abrading the pleural space resulting in obliteration of the potential pleural space. F18-fluorodeoxyglucose (FDG)-uptake on positron emission tomography (PET) in the pleura following talc pleurodesis is an expected finding (Fig. 12).
Decortication (removal of a thick peel off the visceral pleura) and pleurectomy (pleural resection) are procedures performed for empyema11, organized hemothorax, fibrothorax, and tumor (malignant mesothelioma).
Chest wall surgery
Thoracoplasty involves resection of contiguous ribs and possibly intercostal muscles and underlying pleura, in order to obliterate a persistent pleural space in the setting of chronic infection and bronchopleural fistula12 (Fig. 13).
Open drainage (Eloesser flap) is performed for long-term drainage of chronic empyema, and involves creation of a fistula between the skin and pleural space, via a thoracotomy defect13 (Fig. 14).
Minimally invasive surgery
Video-assisted thoracoscopic surgery (VATS) involves percutaneous insertion of a videothoracoscope into the thorax without performing a conventional thoracotomy14 (Fig. 15).
The minimally invasive nature of VATS allows treatment of patients who are not candidates for thoracotomy due to medical comorbidities. VATS is associated with early recovery and less complications. Indications for VATS include biopsy/ excision of lesions in the lung, pleura, and mediastinum, biopsy of aorticopulmonary and bilateral hilar nodes, wedge resection, lung volume reduction surgery, lobectomy, and pleurodesis.
Complications of thoracic surgery
Specific early complications (post-operative day 0-30) related to technique include sutural dehiscence, lung herniation, bronchopleural fistula and cardiac torsion. Other general early complications include pneumonia, empyema, atelectasis, pulmonary embolus and infarction15. Late complications (post-operative day >30) include recurrent tumor, postpneumonectomy syndrome, and anastomotic stricture. Several of these complications, as well as additional ones, are illustrated above.
A large number of CT chest studies are obtained in the post-operative setting. Radiologists need to be aware of the different types of surgeries and their expected post-operative imaging appearance without and with complications.
Sue Loomis, REMS department, Massachusetts General Hospital, for original illustrations.