Chest Wall, Mediastinum, and Trachea

Primary Spontaneous Pneumothorax

Spontaneous pneumothorax is more common in men than in women. The classic characteristic profile is a young, tall, thin man in the second to fourth decade of life. The incidence is approximately 10 per 100,000 population in men and 3 per 100,000 and women. Cigarette smoking also increases the risk of a spontaneous pneumothorax approximately 10- to 20-fold, and the risk increases with the number of cigarettes smoked. The etiology of spontaneous pneumothorax is thought to be rupture of a subpleural bleb and are typically found at CT imaging or surgery in about 80% of patients ( Fig. 1 ). The rate of recurrence after a primary spontaneous pneumothorax is about 25% and is usually within the first or second year after the first episode. The rate of recurrence does increase after each subsequent pneumothorax. Commonly quoted risks are 50% to 60% after the second pneumothorax and even higher after the third. Although the majority of patients have small blebs bilaterally, the risk of contralateral pneumothorax is typically quite low, around 10%.

Secondary Pneumothorax

Secondary pneumothorax occurs in patients with underlying lung disease, and this can cause more serious physiologic embarrassment of the patient. The incidence is fairly similar to primary spontaneous pneumothorax. Importantly, however, patients are typically 15 to 20 years older than patients with primary spontaneous pneumothorax largely due to a large number of patients with emphysema ( Fig. 2 ). The risk of recurrence of a pneumothorax with underlying disease is higher than in spontaneous pneumothorax. A large number of potential lung diseases are associated with secondary spontaneous pneumothorax, but of course the most common is chronic obstructive pulmonary disease ( Box 1 ). Although death is extremely rare with primary spontaneous pneumothorax, it is not uncommon for patients with secondary pneumothorax to die because of the underlying significant lung disease. Cystic fibrosis is probably the next most common cause of secondary pneumothorax, typically represents advanced disease, and is a marker of poor prognosis.

Computed Tomography

CT scans are now commonly performed in the emergency department when evaluating patients with pneumothoraces. Any underlying lung pathology will be quickly identified, and blebs typically at the apex of the upper lobes can be readily identified. It is not uncommon for a CT scan to identify a pneumothorax that was not seen on a plain chest x-ray, especially in the supine patient. CT scans are most helpful in patients with secondary pneumothoraxes where there is a loculated pneumothorax from areas of pleural symphysis that make it extremely challenging to place non–image-guided catheters to drain the pneumothorax and reexpand the lung.

Observation

Although observation is rarely used in patients with secondary pneumothorax, occasionally healthy patients with spontaneous pneumothorax can be observed as an outpatient or with a brief stay in the emergency room observation area. Patients have to be reliable, have good social support, and be relatively close to an emergency room to be safely observed as an outpatient. The most important aspect of this management is that the patient has a history of a period of self-observation at home where the pain and dyspnea happened perhaps one to several days ago before presenting to the emergency department with a small, now relatively asymptomatic pneumothorax. They have already undergone a period of observation. And clinically it appears that the small leak from the lung has sealed since the pneumothorax has remained small. These patients, if reliable, can be sent home from the emergency department and be seen within the next day or two in the physician’s office for a follow-up x-ray. Obviously if they develop a symptomatic pneumothorax, they are instructed to immediately return to the emergency room for treatment.

Aspiration

Aspiration is a controversial management strategy for a spontaneous pneumothorax. It is essentially never done with secondary pneumothorax. Aspiration does require a period of observation for at least several hours in the emergency department with repeat x-rays before discharge and thus does tie up resources in busy emergency rooms. It is most appropriate for patients who really want to avoid hospital admission with placement of a drainage catheter and again are reliable, well-supported patients. It is helpful if there has been at least some period of the patient tolerating the symptoms of pneumothorax before presentation to the emergency room, which presumably suggests that the air leak has sealed. A chest x-ray should confirm a sizable collection of air in the apex of the chest such that introduction of the intravenous catheter does not injure the anterior surface of the lung when inserted. Typically a 16-gauge or 18-gauge intravenous catheter is inserted after local anesthesia is used in the second interspace costal space anteriorly with a three-way stopcock and a large syringe. The metal inner needle cannula is removed as soon as air is aspirated to avoid injury to the underlying lung. Air is then aspirated through the plastic cannula until no further air can be aspirated. The patient is then observed for a period of several hours and a repeat x-ray done. If there is no recurrence, the patient is discharged again with a follow-up x-ray in 1 to 2 days and instructions to return immediately to the emergency room if symptoms recur. The patient should be seen in the office in a few days.

Tube Drainage

The classic treatment of the pneumothorax has been the surgical placement of the tube thoracostomy catheter. This is typically done as a bedside procedure with a thoracostomy tray for instrumentation. It can be a painful procedure, and often it is helpful to provide mild sedation with intravenous narcotics and/or benzodiazepines. The typical placement location recognizes that the chest wall muscle configuration allows placement through the least muscle possible below the axilla, between the anterior and posterior axillary lines, which mark the pectoralis muscle anteriorly and the latissimus muscle posteriorly. Typically, the tube is then placed through slips of the serratus muscle, which is thinner.

The area is widely prepped and draped in a sterile fashion. Typically 1% Xylocaine plain local anesthesia is used. Knowledge of the intercostal bundle and its relationship to the undersurface of the rib is important to avoid injury to the intercostal artery or vein. Accordingly, the pleural space is entered on top of the rib, which minimizes the chance of injury to these vessels that lie at the bottom of each rib. After a skin wheal is made, a small transverse incision is made that is at least as large as the catheter that is going to be placed. Additional local anesthesia is then given through this incision to the underlying soft tissue, the rib, and the interspace that is going to be used. The rib is then palpated with a finger to ensure that the surgeon is placing the instrument just on top of the underlying rib. The rib is then palpated with a surgical clamp, typically a Kelly clamp, and once the top of the rib is found, controlled pressure on the clamp is used to enter the pleural space. The clamp is then spread to widen the passageway before the tube is placed. Thereafter, a clamp is used to squeeze and narrow the end of the chest tube; this is placed into the pleural space, and an attempt is made to thread the catheter apically. A technique of ballottement is often used to facilitate placement in the apex as the chest tube can hang up on the fissure of the lung, an osteophyte, or a rib. The surgeon should have a rough indication as to how far the tube should be inserted to reach the apex and should attempt to insert it to that distance. The tube is then connected to a pleural drainage device. The tube is then secured with heavy sutures to prevent dislodgment, and a dry sterile dressing is applied. Vaseline gauze is not used as that can promote infection. Typically, the tube is placed to suction if the pneumothorax was small, but with large pneumothorax it is often helpful to place it to waterseal for a period of time to allow slower lung expansion and avoid the phenomenon of reexpansion pulmonary edema, which is rarely seen. The reexpansion of a significantly shrunken lung often leads to paroxysms of coughing and pain, which the surgeon needs to talk the patient through. The coughing goes away once the lung is totally reexpanded. A chest x-ray is then performed to confirm the position of the chest tube and that the evacuation of the pneumothorax was appropriate. The patient is then monitored for air leakage, and subsequent chest x-rays are done as clinically appropriate. There are some chest tube insertion kits that come with a trocar insertion device. Care must be used when using a trocar technique to avoid inadvertent injury to the heart or lung. These are safe if there is a large pneumothorax and a significant air gap between the lung edge and ribs. If there is any pleural symphysis at the insertion point, lung injury will occur. Alternatively, there are some chest tube insertion kits that have a plastic insertion device that hooks onto the tip of the chest tube and can facilitate chest tube placement with much less possibility of damage to the lung.

In recent years, the numbers of tube thoracostomies have fallen off as the insertion of much smaller catheters that use the Seldinger technique have become very popular ( Fig. 6 ). These catheters were first used many years ago by our interventional radiology colleagues and now have been widely used in emergency rooms, intensive care units, and at the bedside for less invasive chest drainage. The catheters themselves typically have a pigtail shape at the end once the insertion stylette is removed. These catheters are softer and smaller than typical chest tubes and cause less patient discomfort. As long as there is a significant pneumothorax, they are easy to insert. The disadvantage of these catheters is that they have very small diameter, are more easily kinked, and the small holes within the chest can become clogged with serum or blood. Furthermore, if there is a very large air leak, they may not be large enough to adequately evacuate the pleural space. However for most patients with a spontaneous pneumothorax, they are more than adequate.

The insertion technique mirrors that of open tube thoracostomy. A sterile field is created, local anesthesia is used, and the needle for the local anesthesia is aspirated for air once it enters the pleural space to confirm a pneumothorax is present, which is amenable to pigtail catheter placement. A guidewire is then passed through the needle, which has a soft flexible tip. A stiff dilator is then typically passed over the wire to slightly widen the insertion site, and then the dilator is carefully removed leaving the wire in place. Thereafter, the catheter is threaded onto the guidewire and advanced into the chest toward the apex. The catheter is then secured with a suture, a dry sterile dressing is applied, and the catheter is attached to a pleural drainage system. The catheter generally should be placed in a similar position as a tube thoracostomy. In men with relatively thin chest walls and an apical pneumothorax, they may be placed in the second intercostal space anteriorly in the midclavicular line. In general, we do not utilize this access point for a woman as it can cause unsightly scarring to the breast area.

The use of these small, less invasive pigtail catheters has led to an increased treatment of spontaneous pneumothorax in appropriate patients as an outpatient. The catheters can be hooked up to a Heimlich valve, a very small drainage collection receptacle that also has a one-way valve, or a small portable complete pleural drainage system that can be attached to a shoulder strap. The patients can then be discharged from the emergency room and seen in the office for follow-up in a couple of days at which time air leaks have usually sealed. An x-ray should have confirmed that the pneumothorax has resolved after pigtail placement, and obviously the patient must be carefully selected so they can safely manage such a device at home.

Chemical Pleurodesis

The goal of the pleurodesis is to cause significant adhesions between the visceral and parietal pleura to obliterate the pleural space. This can seal an ongoing air leak or prevent future pneumothoraxes if the area of pleural symphysis is where a ruptured bleb occurs. Chemical pleurodesis is uncommonly performed for first-time spontaneous pneumothoraces. Chemical pleurodesis is typically performed for recurrent, difficult to control pneumothoraces, especially after a previous operative intervention. Bedside pleurodesis is much more commonly performed with secondary pneumothoraces to avoid operative intervention in patients at high risk for an operative procedure. Typically, a doxycycline solution (500 mg to 1 g) or a sterile talc slurry (4–5 g) is used for bedside pleurodesis. Talc is more effective than doxycycline at creating a pleural symphysis, but there are some concerns about using talc in young people with a spontaneous pneumothorax. Previous versions of talc were not guaranteed to be asbestos-free raising concern for late mesothelioma. However current versions of FDA-approved talc are asbestos-free. In addition, the symphysis caused by talc is usually quite strong, and if the patient was ever to need another thoracic operation, it makes that subsequent operation much more difficult because of the severe adhesions. Obviously, this is a relatively uncommon scenario. Pleurodesis with either these agents typically cause a fair degree of pleuritic chest pain, and the patient should be cautioned about this and pain medicine made available for patient comfort. For pleurodesis to work, obviously there should be relatively complete apposition of the visceral and parietal pleura such that adhesions can form. If the patient has an ongoing air leak, the chest tube drainage system should not be clamped to allow pleurodesis to occur as this could lead to a tension pneumothorax. Typically, after sterilely prepping the drainage system tubing close to the chest tube insertion point, a needle is passed obliquely through the tubing such that it will seal quickly when the needle is removed. A large syringe is then used to inject the sclerosing solution, the needle is withdrawn, and then a clear plastic self-adherent dressing is placed over the insertion point to make sure that is sealed. If the patient has no air leak, the chest tube can be clamped to allow the solution to remain in the chest for 1 to 2 hours. If the patient has an ongoing air leak, the chest tube drainage tubing system can be hooked around an IV pole such that the solution remains in the chest once the injection is complete. There are rare cases of ARDS after talc is used related to both a very small particle size as well as doses over 5 g. For that reason, the typical adult dose is 4 to 5 g of talc. The chest drainage system is then placed on suction, typically for 1 to 2 days at a minimum, to ensure maximum pleural apposition to obtain the best possible pleurodesis.

Video-Assisted Thoracic Surgery

The advent of minimally invasive surgery for the chest, video-assisted thoracic surgery (VATS), has lowered the threshold for operative intervention for a pneumothorax. The indications for operative intervention are not particularly firm. The clearest indication for operative therapy is a recurrent pneumothorax, a patient with a first-time spontaneous pneumothorax with an ongoing air leak after 2 to 3 days, or the rare patient with a bilateral pneumothorax. Other indications include patients who present with a tension pneumothorax; patients with an identified large bleb; or patients with lifestyle issues such as pilots, scuba divers, or people who travel to areas without access to good medical care. Some patients elect to have operative intervention during the first hospital admission given the recurrence rate, which approaches about one-third, to reduce the chance of a recurrence.

VATS is typically performed under general anesthesia with three small incisions: one for the camera and the other ports for a stapler and forceps. It is, however, possible to do VATS under local anesthesia with sedation in thin, appropriately selected, compliant patients. In addition, uniportal VATS is certainly possible with a slightly larger main incision with this relatively simple surgical procedure. The lung is carefully explored, concentrating on the apex of the upper lobe and the tip of the superior segment of the lower lobe, which is where most blebs occur. Blebs are then typically stapled off with an endoscopic stapler. Most surgeons perform some sort of mechanical pleurodesis with a small gauze sponge, an electrocautery scratchpad, or with an energy device such as an argon beam coagulator. Alternatively, for high-risk patients, an apical pleurectomy is sometimes done, which is the most effective operative pleurodesis technique. However, this comes at the cost of longer operative times, increased risk of bleeding, and a slight risk of injury to adjacent structures such as the intercostal bundle or the stellate ganglion. A drainage catheter is placed after the procedure, and most patients can be discharged in 1 or 2 days. In patients with severe chronic obstructive pulmonary disease (COPD) who are being operated on, there can be significant leakage from the poor-quality lung at the staple line; these can be reinforced with commercially available buttressed staple loads or sealed with commercially available lung sealants. Talc pleurodesis is often used in patients with a secondary pneumothorax secondary to COPD to minimize the chance of recurrence.

Benign Bony and Cartilaginous Tumors

Fibrous Dysplasia

The most common benign bony tumor of the chest wall, fibrous dysplasia represents a lesion in which normal marrow and cancellous bone is replaced with a fibrous stroma ( Fig. 1 ). It typically presents as a painless mass of the rib, commonly located posteriorly or laterally on the chest wall. Radiographic findings are variable but often include a central ground-glass appearance with punctate calcifications and peripheral cortical thinning. These tumors most commonly present as a solitary lesion in otherwise healthy individuals 20 to 30 years of age. They can, however, be multiple and are associated with McCune-Albright syndrome, which includes cutaneous manifestations and endocrine abnormalities in the context of short stature and precocious puberty. Surgical therapy is only indicated if the diagnosis is in doubt or if the lesion is symptomatic. In such cases, limited partial rib resection is the definitive treatment.

Malignant Bony and Cartilaginous Tumors

Chondrosarcomas

Chondrosarcomas are the most common primary malignant chest wall tumor ( Fig. 2 ). They occur most frequently in the fourth to seventh decades of life and are slightly more common in men than in women. They are typically located anteriorly and involve either the costochondral junction or the sternum. On imaging, irregular margins and bony destruction are typical. Early-stage lesions can retain a thickened cortical cap, whereas more advanced tumors progress to complete cortical destruction and an associated soft tissue mass. Suspected benign chondromas in which the cortical cap thickens over time may be in the process of malignant degeneration into chondrosarcoma. All suspected chondrosarcomas should undergo wide local excision; they often require chest wall reconstruction. Poor prognostic factors include hypercellularity, cytologic atypia, high mitotic index, and larger tumor size. High-grade tumors have a 75% chance of distant spread at the time of diagnosis. Because these tumors respond poorly to chemotherapy or radiation, complete surgical excision is the primary treatment modality. Studies demonstrate that inadequate resection margins in chondrosarcoma are associated with significantly higher local recurrence and lower overall survival.

Benign Soft Tissue Tumors

Malignant Soft Tissue Tumors