Thoracic surgery is any surgery performed in the chest (thorax).
The purpose of thoracic surgery is to treat diseased or injured organs in the thorax, including the esophagus (muscular tube that passes food to the stomach), trachea (windpipe that branches to form the right bronchus and the left bronchus), pleura (membranes that cover and protect the lung), mediastinum (area separating the left and right lungs), chest wall, diaphragm, heart, and lungs.
General thoracic surgery is a field that specializes in diseases of the lungs and esophagus. The field also encompasses accidents and injuries to the chest, esophageal disorders (esophageal cancer or esophagitis), lung cancer, lung transplantation , and surgery for emphysema.
The most common diseases requiring thoracic surgery include lung cancer, chest trauma, esophageal cancer, emphysema, and lung transplantation.
Lung cancer is one of the most significant public health problems in the United States and the world. Approximately 171,600 new cases of lung cancer occurred in 1999. It accounts for 28% of cancer deaths, 14% of all cancer diagnoses, and is the leading cause of cancer deaths among women and second most common cause of male cancer deaths. The five-year survival rate in localized disease can approach 50% (stages I and II).
Lung cancer develops primarily by exposure to toxic chemicals. Cigarette smoking is the most important risk factor responsible for the disease. Other environmental factors that may predispose a person to lung cancer include such industrial substances as arsenic, nickel, chromium, asbestos, radon, organic chemicals, air pollution, and radiation.
Most cases of lung cancer develop in the right lung because it contains the majority (55%) of lung tissue. Additionally, lung cancer occurs more frequently in the upper lobes of the lung than in the lower lobes. The tumor receives blood from the bronchial artery (a major artery in the pulmonary system).
Adenocarcinoma of the lung is the most frequent type of lung cancer, accounting for 45% of all cases. This type of cancer can spread (metastasize) earlier than another type of lung cancer called squamous cell carcinoma (which occurs in approximately 30% of lung cancer patients). Approximately 66% of squamous cell carcinoma cases are centrally located. They expand against the bronchus, causing compression. Small-cell carcinoma accounts for 20% of all lung cancers; and the majority (80%) are centrally located. Small-cell carcinoma is a highly aggressive lung cancer, with early metastasis to such distant sites as the brain and bone marrow (the central portion of certain bones, which produce formed elements that are part of blood).
Most lung tumors are not treated with thoracic surgery since patients seek medical care later in the disease process. Chemotherapy increases the rate of survival in patients with limited (not advanced) disease. Surgery may be useful for staging or diagnosis. Pulmonary resection (removal of the tumor and neighboring lymph nodes) can be curative if the tumor is less than or equal to 3 cm, and presents as a solitary nodule. Lung tumors spread to other areas through neighboring lymphatic channels. Even if thoracic surgery is performed, postoperative chemotherapy may also be indicated to provide comprehensive treatment (i.e., to kill any tumor cells that may have spread via the lymphatic system).
Genetic engineering has provided insights related to the growth of tumors. A genetic mutation called a k-ras mutation frequently occurs, and is implicated in 90% of genetic mutations for adenocarcinoma of the lung. Mutations in the cancer cells make them resistant to chemotherapy, necessitating the use of multiple chemotherapeutic agents.
Chest trauma is a medical/surgical emergency. Initially, the chest should be examined after an airway is maintained. The mortality (death) rate for trauma patients with respiratory distress is approximately 50%. This figure rises to 75% if symptoms include both respiratory distress and shock. Patients with respiratory distress require endotracheal intubation (passing a plastic tube from the mouth to the windpipe) and mechanically assisted ventilator support. Invasive thoracic procedures are necessary in emergency situations.
Trauma requiring urgent thoracic surgery may include any of the following problems: a large clotted hemothorax, massive air leak, esophageal injury, valvular cardiac (heart) injury, proven damage to blood vessels in the heart, or chest wall defect.
The number of new cases of esophageal cancer is slowly rising (approximately 3.2 per 100,000 persons under age 80) in the United States, United Kingdom, and Western Europe. The cause of esophageal cancer is not precisely known. The types of esophageal cancers include lymphomas, epithelial tumors, metastatic tumors, and sarcomas. Chronic irritation of the esophagus from a broad range of chemicals may be partially implicated in development of esophageal cancer.
Difficulty swallowing (dysphagia) is the cardinal symptom of esophageal cancer. Radiography, endoscopy, computerized axial tomography (CT scan), and ultrasonography are part of a comprehensive diagnostic evaluation. The standard operation for patients with resectable esophageal carcinoma includes removal of the tumor from the esophagus, a portion of the stomach, and the lymph nodes (within the cancerous region).
Smoking and alcohol consumption are implicated in the development of squamous cell carcinoma. Adenocarcinomas can develop from continued acid reflux (gastroesophageal reflux). Over 90% of patients with esophageal squamous cell carcinoma develop the tumor in the upper and middle thoracic esophagus.
Lung volume reduction surgery (LVRS) is the term used to desribe surgery for patients with emphysema. LVRS is intended to help persons whose disabling dyspnea (difficulty breathing) is related to emphysema and does not respond to medical management. Breathlessness is a result of the structural and functional pulmonary and thoracic abnormalities associated with emphysema. Surgery will assist the patient, but the primary pathogenic process that caused the emphysema is permanent because lung tissues lose the capability of elastic recoil during normal breathing (inspiration and expiration).
Patients are usually transferred out of the intensive care unit within one day of surgery. Physical therapy and rehabilitation (coughing and breathing exercises) begin soon after surgery, and the patient is discharged when deemed clinically stable.
There are various types of lung transplantations: unilateral (one lung; most common type); bilateral (both lungs); heart-lung; and living donor lobe transplantation.
The long-term survival for persons receiving lung transplantation has not improved over time, and is approximately 3.5 years. A successful outcome is dependent on the patient's general medical condition. Those who have symptomatic osteoporosis (severe disease of the musculoskeletal system) or are users of corticosteroids may not have favorable outcomes.
The death rate is due to infections (pulmonary infections) or chronic rejection (bronchiolitis obliterans) if the donor lung was not a perfect genetic match. Patients are given postoperative antibiotics to prevent bacterial infections during the early period following surgery.
Bacterial pneumonia is usually severe. A bacterial genus known as Pseudomonas accounts for 75% of post-transplant pneumonia cases. Patients can also acquire viral and fungal infections, and an infection caused by a cell parasite known as Pneumocystis carinii. Infections are treated with specific medications intended to destroy the invading microorganism. Viral infections require treatment of symptoms.
Acute (quick onset) rejection is common within the first weeks after lung transplantation. Acute rejection is treated with steroids (bolus given intravenously), and is effective in 80% of cases. Chronic rejection is the most common problem, and typically begins with symptoms of fatigue and a vague feeling of illness. Treatment is difficult, and the results are unrewarding. There are several immunosuppressive protocols currently utilized for cases of chronic rejection. The goal of immunosuppressive therapy is to prevent the host's immune reaction from destroying the genetically foreign organ.
The surgeon may use two common incisional approaches: sternotomy (incision through and down the breastbone) or via the side of the chest ( thoracotomy ).
An operative procedure known as video assisted thoracoscopic surgery (VATS) is minimally invasive. During VATS, a lung is collapsed and the thoracoscope and surgical instruments are inserted into the thorax through any of three to four small incisions in the chest wall.
Another approach involves the use of a mediastinoscope or bronchoscope to visualize the internal anatomical structures during thoracic surgery or diagnostic procedures.
Preoperative evaluation for most patients (except emergency cases) must include cardiac tests, blood chemistry analysis, and physical examination . Like most operative procedures, the patient should not eat or drink food 10–12 hours prior to surgery. Patients who undergo thoracic surgery with the video-assisted approach tend to have shorter inpatient hospital stays.
Patients typically experience severe pain after surgery, and are given appropriate medications. In uncomplicated cases, chest and urine (Foley catheter) tubes are usually removed within 24–48 hours. A highly trained and comprehensive team of respiratory therapists and nurses is vital for postoperative care that results in improved lung function via deep breathing and coughing exercises.
Precautions for thoracic surgery include coagulation blood disorders (disorders that prevent normal blood clotting) and previous thoracic surgery. Risks include hemorrhage, myocardial infarction (heart attack), stroke, nerve injury, embolism (blood clot or air bubble that obstructs an artery), and infection. Total lung collapse can occur from fluid or air accumulation, as a result of chest tubes that are routinely placed after surgery for drainage.
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American Association for Thoracic Surgery. 900 Cummings Center, Suite 221-U, Beverly, Massachusetts 01915. (978) 927-8330. Fax: (978) 524-8890. E-mail: email@example.com.
Laith Farid Gulli, M.D., M.S. Abraham F. Ettaher, M.D. Nicole Mallory, M.S., PA-C
WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?
Thoracic surgery is performed by a specialist in general surgery who has received advanced training in thoracic surgery.