STS Benchmark - Thoracic

Question 1

A maximum oxygen consumption greater than what is consistent with a normal perioperative risk?

Answer 1

1 L/min (or greater than 15 ml/(kg*min)

Question 2

A 67-year-old man is postoperative day 9 following transhiatal esophagectomy with cervical esophagogastric anastomosis. He complained of a “lump” in his throat when swallowing soft foods, so a bedside esophageal dilation was performed using topical benzocaine anesthesia for suspected anastomotic stricture. Fifteen minutes after the procedure, the nurse reported that the patient is cyanotic with an O2 saturation of 69% on 100% supplemental oxygen. Breath sounds are audible on both sides and the patient is awake and complains of a headache. The next step in this patient’s management should be?

Answer 2

intravenous methylene blue (1-2 mg/kg)

The administration of benzocaine should prompt consideration of drug-induced methemoglobinemia. In healthy adults, methemoglobin (MetHb) accounts for less than 2% of total hemoglobin. Oxidizing agents (including benzocaine) are thought to cause oxidative stress that oxidizes iron in hemoglobin from the ferrous (Fe2+) to the ferric (Fe3+) state at a rate much faster than it can be metabolized. The reaction is not dose related. The resulting methemoglobin is incapable of carrying releasable oxygen and can lead to severe tissue ischemia. Inherited forms of methemoglobinemia are rare. The drug-induced syndrome is uncommon, with a reported incidence of 1/7000 bronchoscopies when benzocaine preparation was routinely used. Other drugs responsible include amyl nitrite, nitroglycerin, dapsone, phenacetin, phenytoin, primaquine, sulfonamides, and other local anesthetics such as lidocaine.

Clinical findings of methemoglobinemia range in severity from cyanosis and dizziness to coma. Other findings may include dyspnea, tachycardia, lethargy, headache, mental status change, or stupor in addition to cyanosis. A blood sample that is drawn and demonstrates a “chocolate brown” color that does not change red upon exposure to room air is pathognomonic for methemoglobinemia. Arterial blood gas and standard pulse oximetry are often incongruous, with normal ABG values (pO2 reflects dissolved oxygen) and unstable or severely depressed oximetry. The MetHb level may be determined in the laboratory, but clinical recognition and immediate treatment can be life-saving. Treatment includes 100% oxygen administration and methylene blue (1-2 mg/kg IV up to 50mg/dose in adults) as a 1% solution over 5 minutes. Methylene blue accelerates the reduction of MetHb via the NADPH-MetHb reductase pathway and is the treatment of choice. Improvement should occur in less than 10 minutes and maximum effect should be seen within 30 minutes. The patient should be closely monitored, as rebound has been reported and repeat treatment with methylene blue can be effective.

Methylene blue should not be used in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency, the most common inherited human enzyme defect. G6PD is an X-linked recessive disorder affecting mostly African, Mediterranean and far-eastern populations (male:female = 5:1). Most patients are asymptomatic, but manifestations include anemia, jaundice, and non-immune hemolytic crises. Methylene blue can, therefore, incite hemolysis and paradoxically worsen the methemoglobinemia in these patients.

Question 3

On post op day 2 after a right upper lobectomy the patient is tachycardic and febrile to 101.4 F. A chest X-ray reveals a consolidated and collapsed right middle lobe.
Differential?
What would be the catastrophic diagnosis?
Appropriate next step?

Answer 3

Mucus plugging or post-op pneumonia are most common.
Right middle lobe torsion is an uncommon but potentially catastrophic complication of right upper or lower lobectomies.

Bronchoscopy and/or a CT Chest with contrast can diagnose right middle lobe torsion. On CT the lobe may be seen with a “twisted” hilum and is not perfused. On bronchoscopy the right middle lobe orifice is occluded and can appear twisted -> immediate re-operation to correct or resect the right middle lobe. Bronch has the advantage of being done in the operating room while readying for a reoperation.

Question 4

ECOG Performance Status Grades:

Answer 4

0 Fully active, able to carry on all pre-disease performance without restriction
1 Restricted in physically strenuous activity but ambulatory and able to carry out work of a
light or sedentary nature, e.g., light house work, office work
2 Ambulatory and capable of all self-care but unable to carry out any work activities. Up and
about more than 50% of waking hours
3 Capable of only limited selfcare, confined to bed or chair more than 50% of waking hours
4 Completely disabled. Cannot carry on any selfcare. Totally confined to bed or chair
5 Dead

Question 5

Arterial hypoxemia during one-lung anesthesia may be minimized by?

Answer 5

Most issues relate to improper positioning of the double lumen endotracheal tube.

Hypoxemia can be due to shunting of blood to the nonventilated lung, ventilation- perfusion abnormalities in the ventilated lung, and reduction in cardiac output.

The application of low levels of positive end-expiratory pressure, generous tidal volumes to the ventilated lung, and the use of continuous positive airway pressure to the nonventilated lung are methods which can be used intraoperatively to improve oxygenation.

Question 6

Most traumatic tracheobronchial disruptions occur within 2.5 cm of the carina and most commonly involve the junction of the membranous and cartilaginous airway or between rings. Once a large airway injury is suspected (large, blowing air leak after 2 tubes w/o resolution of the PTX), what should be done?

Answer 6

Mainstem intubation should be considered, but don’t delay OR -> bronchoscopy with mainstem of tube, R thoracotomy.

Distal tracheal, right mainstem, and proximal left mainstem airway injuries can be approached through a right thoracotomy. Considerable external force is required to produce an airway injury, and serious associated injuries are frequent. These other injuries often determine patient outcome.

Question 7

An 18-year-old man was the restrained driver involved in a motor vehicle crash. He was intubated in the ER for hypoxemia and respiratory distress, hemodynamics are stable. A CXR revealed bilateral rib fractures and pneumothoraces with diffuse fluffy infiltrates. Bilateral chest tubes were placed. Further evaluation reveals an aortic transection at the isthmus and severe bilateral pulmonary contusions. The patient now continues to have persistent hypoxemia with arterial oxygen saturation of 80% on FiO2 1.0 and PEEP 15 cmH20. The best treatment strategy is?

Answer 7

Given that he is hemodynamically stable, the aortic repair should be delayed to improve his pulmonary status with an ARDS protocol ventilator strategy and inhaled prostacyclin. Compared to open repair, endovascular treatment of blunt traumatic aortic injury is associated with less blood transfusions (which can potentially worsen the lung injury) and improved overall survival. Aortic repair in patients who sustain traumatic blunt aortic injuries and are hemodynamically stable can be safely delayed > 24 hours. Observing a priority of treating more life-threatening injuries first results in improved outcomes.

Question 8

A 55-year-old man was involved in a high speed motor vehicle crash 6 months ago. He had a prolonged hospitalization with multiple fractures of his spine and lower extremities that required operative repair. A CXR at that time was normal. He now complains of intermittent abdominal pain and presents with nausea and vomiting for the past 3 days. Images from the chest CT are shown. The best next step is

Answer 8

Regardless of the operative plan, initial management of patients with intestinal obstruction from incarcerated stomach or other intestinal viscera should include nasogastric decompression. The optimal surgical approach is dictated by clinical circumstances. In acute cases where abdominal exploration is mandatory, laparotomy or laparoscopy can be performed. In cases where pulmonary injury requires intervention, thoracotomy or thoracoscopy are also both possible. In late presentations, open or minimally invasive approaches are possible. Diaphragmatic defects can typically be closed primarily due to the laxity of the diaphragmatic muscle. In situations with acute loss of tissue, synthetic and biologic mesh have been used. When contamination is present, the chest and abdomen should be irrigated and a tissue flap (omentum or latissimus muscle) or biologic mesh can be used to close the defect.

Traumatic diaphragmatic hernias are rare and occur in less than 1% of all trauma patients admitted to the hospital. Males with blunt trauma account for over two-thirds of cases. Most injuries are left sided. Penetrating trauma from knife or bullet wounds can also lead to diaphragmatic injury, and other causes include labor in women with prior diaphragmatic repair or eventration. The mechanism of injury is postulated to be due to shearing of the stretched diaphragm from a sudden increase in intraabdominal pressure. The liver is thought to afford protection from right sided herniation. The right side of the diaphragm may also be stronger, with fewer points at risk for detachment.

Symptoms from acute rupture can include respiratory distress with decreased breath sounds and abdominal pain if intestinal obstruction develops from the herniated viscera. Chronic diaphragmatic herniation or delayed presentation of a blunt injury from trauma is surprisingly common. Presenting symptoms are usually those of intestinal obstruction, chiefly nausea and vomiting. However, symptoms can be subtle and a high index of suspicion is required to make a diagnosis in these cases.

Diaphragm injuries can be classified according to the American Association for the Surgery of Trauma (AAST) organ injury scale. The degree of injury, however, has not been correlated with morbidity or mortality as for other organ injury scales (e.g., liver, spleen)

Traumatic rupture of the diaphragm mandates surgical intervention. In acute presentations, emergent abdominal exploration is mandated after initial resuscitation due the high likelihood of injury to abdominal organs. Patients who present late also require intervention, as herniated viscera may strangulate. Radiologic studies to confirm the diagnosis may include only PA/Lat chest films in patients with large defects, or a upper gastrointestinal series and/or abdominal CT in more subtle cases. False positives can be seen in patients with diaphragmatic paralysis or eventration.

Question 9

A patient sustained penetrating chest trauma. On initial assessment, he did not appear to have a cardiac injury by Focused Assessment with Sonography in Trauma (FAST) criteria, but he did have a right lung injury. The initial chest tube output did not warrant immediate operative intervention and his oxygenation was adequate. However, the newest assessments show a retained hemothorax with ongoing blood loss and his vital signs are decompensating.
Next step?

Answer 9

right exploratory thoracotomy

Chest tube output >800 mL over 4-8 hours requires surgical exploration. Securing his airway and operative intervention is warranted in order to gain control of the bleeding and to evacuate the retained hemothorax. Video-assisted thoracoscopic surgery (VATS) is not appropriate for a hemodynamically unstable patient.

Question 10

What is eventration of the diaphragm?
How do you diagnose, workup, and manage?

Answer 10

Eventration of the diaphragm can be congenital or acquired. Most are congenital in nature, in which all or parts of the diaphragm muscle is replaced with fibroelastic tissue. The central portion of the diaphragm is commonly affected. The dysfunctional pathophysiology can be due to the absence of the phrenic nerve or deficient diaphragm muscle development. Partial defects are most common and involve the anteromedial segment of the right hemidiaphragm. Total absence of the muscle leads to the development of a thin membrane replacing the entire diaphragm. Males are more commonly affected than females. Acquired eventration is due to phrenic injury. In children this can result from birth or from injury sustained during repair of congenital diaphragmatic hernias. Adults are rarely symptomatic from a diaphragmatic eventration. Symptoms, if present, include shortness of breath, chest pain, dysphagia, or recurrent pneumonias.

The diagnosis of eventration is suggested by a CXR demonstrating elevation of the diaphragm, often with a focal bulge. Normal hemidiaphragms move inferiorly with inhalation. Fluoroscopy or chest ultrasound with sniff testing may show reduced or delayed excursion of the involved segment during inspiration, but relatively normal excursion of the overall diaphragm. The different responses between the eventration and normal diaphragm can sometimes result in a “rocking” motion on the lateral view. In cases where the phrenic nerve was injured, the paralyzed diaphragm is characterized by no orthograde movement with quiet breathing and paradoxical motion on sniffing. Phrenic nerve studies are typically normal in eventration except when there was also phrenic nerve injury. Nerve conduction studies, therefore, are not indicated as an initial study since diaphragmatic pacing does not have a role in the management of eventration.

Symptomatic patients can be treated by imbrication/plication of the diaphragm to allow for lung expansion and placement of abdominal contents in the proper position. In cases of long standing eventration, the lung may be unable to expand due to chronic atelectasis (“hepatization”). Traditionally, a thoracotomy has been performed for plication but minimally invasive thoracoscopic and laparoscopic approaches have been described. Care should be taken to ensure that the abdominal viscera are not injured if the plication is performed in the chest.

Question 11

Abdominal herniation into the pericardial cavity - most often congenital or acquired?

Answer 11

Abdominal herniation into the pericardial cavity is most often a congenital abnormality. This can occur in adults from severe blunt trauma, but the associated injuries are most often fatal. Isolated pericardial/diaphragm rupture is a rare injury, with literature claims that this is the rarest type of diaphragm hernia.

Question 12

Will mask ventilation help a cyanotic newborn with a diaphragmatic hernia?

Answer 12

Mask ventilation is contraindicated because distension of gastrointestinal contents with worsening distress may occur.

Chest radiography will demonstrate loops of bowel within the right chest and may exclude other cause of respiratory distress. Echocardiography will confirm or exclude associated congenital heart defects. A nasogastric tube will lessen gastrointestinal gas distension.

Question 13

The pathogenesis of congenital lobar emphysema is?

Answer 13

The usual pathogenesis is absent or abnormal bronchial cartilage which results in dynamic obstruction during expiration and resultant air trapping (see radiograph). Less frequent secondary causes of this appearance include foreign body aspiration or obstruction from pulmonary artery sling or vascular ring anomalies.

Symptoms are present in infancy and the chest radiograph demonstrates hyperaeration of the involved lobe, compressive atelectasis of other lobes and mediastinal shift. Antenatal diagnosis is increasingly accurate for congenital lobar emphysema, cystic adenomatoid malformation, sequestration and other cystic anomalies and congenital lung malformations. Minimizing barotrauma during required mechanical ventilation may limit the need for urgent surgery, and temporary palliation may be achieved by selective intubation of the opposite side and positioning with the overinflated side down.

Emergency lobectomy remains the appropriate treatment for infants with gross hyperexpansion. Since bronchoscopy is often not possible in small infants, the pulmonary hilum should be examined at the time of thoracotomy to ensure that there is no extrinsic obstruction of the involved bronchus. Approximately 10% of these children have associated anomalies, which are dominated by congenital heart lesions. Inadequate surfactant production is responsible for respiratory distress in premature infants while inadequate surfactant clearance has been implicated in the pathogenesis of pulmonary alveolar proteinosis. Maternal nicotine use has been correlated with sudden infant death syndrome.

Congenital lobar emphysema refers to the isolated hyperinflation of a lobe in the absence of extrinsic bronchial obstruction. This is the most common congenital lung malformation, and it effects the left upper lobe most frequently.

Question 14

The most common reason for resection of a lung nodule subsequently proven to be coccidioides is?

Answer 14

The most common indication for coccidioides nodule resection is suspected malignancy.

Radiographically, coccidioidomycosis often presents as a solitary pulmonary nodule. The nodules may cavitate and there may be regional lymphadenopathy or a parenchymal infiltrate. The histologic picture is one of granuloma formation with suppuration. While the nodules can cavitate, this alone is not an indication for resection. Hemoptysis from a cavitary lesion is rare. The diagnosis of coccidioides can be confirmed serologically, but it is often made clinically in patients living in endemic areas. If the pulmonary lesion resolves, a histologic diagnosis is not needed. In immunocompromised patients, or those about to undergo bone marrow transplantation, resection of a coccidioides granuloma is indicated to prevent reactivation.
The outcome of antifungal therapy for coccidioidomycosis is unreliable, even compared to other fungal diseases. Fortunately, only about 5% of patients require treatment, which may include amphotericin B, fluconazole, ketoconazole or isoniazid.

Coccidioides immitis is fungus that is endemic to the soil of the Southwestern United States. Coccidioidomycosis, also known as San Joaquin Valley fever and “cocci,” is acquired from inhalation of the soil-resident spores (arthroconidia). Once in the lungs, the spores transform into spherules. An acute respiratory infection occurs 7 to 21 days after exposure and typically resolves rapidly. Some patients develop chronic pulmonary changes and symptoms, and this is particularly common in Filipinos and Blacks. Pregnant women are at particular risk of extrapulmonary coccidioidomycosis.

Question 15

The most efficacious and least invasive procedure which accomplishes palliative control/prevention for malignant pleural mesothelioma (MPM) associated pleural effusions (dyspnea sx) is?

Answer 15

thoracoscopy with talc pleurodesis

Success rate for effusion control with talc approach 90%. Failures are usually associated with entrapped lung, large tumor mass, or multiple loculations. In these rare cases, pleurectomy with or without decortication is the procedure of choice. EPP has a morbidity and mortality rate which are prohibitive for palliative application.

The role of surgery in the management of malignant pleural mesothelioma (MPM) includes diagnosis, palliative therapy, or part of multimodality therapy. Operative intervention for MPM is for primary effusion control, cytoreduction before chemotherapy and radiation, or to deliver and monitor innovative intrapleural therapy. The procedures used include thoracoscopy, pleurectomy/decortication (PD), and extrapleural pneumonectomy (EPP).

Surgery with either EPP or pleurectomy and decortication provide cytoreduction for patients with MPM, but they are only part of an aggressive treatment plan for these patients. EPP has been classically described for stage I tumors with pure epithelial histology. Because of sampling error, it is impossible to be completely certain whether the tumor is pure epithelial or mixed based on preoperative biopsy. The best post-treatment survival is associated with epithelial histology and negative nodes and margins. Modern series combine cytoreductive therapy with adjuvant cisplatin-based chemotherapy and irradiation. Because the lung is removed by extrapleural pneumonectomy, intense external beam irradiation can be targeted optimally at areas of positive margins or lymph nodes, and higher total doses of can be delivered than when the lung is present. Significant morbidity is encountered by over half of all patients following EPP, but postoperative mortality has decreased from 30% to less than 10% over the past 30 years. Death occurs chiefly in older patients from respiratory failure, myocardial ischemia, or pulmonary embolism.

Question 16

A parapneumonic effusion can have a high probability of developing into a classic empyema. S/p thoracentesis, a pleural fluid pH of less than 7.0 in this situation is a strong indication for?

Answer 16

tube thoracostomy

A decortication or an Eloesser flap are reserved for more chronic empyemas, and in this case would be considered over zealous. Daily thoracentesis is not adequate.

Question 17

Spontaneous pneumothorax is associated with each of the following:
* Menses
* Metastatic sarcoma
* Sarcoidosis

Explain how.

Answer 17

Spontaneous pneumothorax is known to be associated with the menstrual period. At thoracoscopy or thoracotomy, endometrial tissue may be found on the surface of the diaphragm and occasionally, small defects are also present. One hypothesis is that air comes through the uterus and fallopian tubes into the abdominal cavity and then into the chest through the small defects in the diaphragm. A second is the hormonally responsive endometrial tissue that has invaded the surface of the lung, necrosis and sloughs in concert with the same process in the uterus–causing air leaks in the surface of the lung. It is not known how the diaphragmatic defects are associated with the endometrial deposits.

Metastatic sarcomas are usually located at the periphery of the lung. As they enlarge, they develop necrosis with disruption of the surface of the tumor causing a spontaneous pneumothorax.

Pulmonary histiocytosis results in cystic changes in the lung parenchyma. A small cyst may rupture and cause a spontaneous pneumothorax.

Spontaneous pneumothorax is an occasional complication of sarcoidosis. Obstruction of small bronchi by fibrosis or larger bronchi by enlarged lymph nodes can result in focal emphasemateous changes. These areas can rupture into the pleural space.

Question 18

Can necrosis or cystic degeneration occur with pulmonary eosinophilia causing spontaneous pneumothorax?

Answer 18

Pulmonary eosinophillia consists of patchy areas of alveolar exudate with many eosinophills. Necrosis or cystic degeneration does not occur and spontaneous pneumothorax is not associated with this disease process.

Question 19

Most common malignant primary chest wall tumor?
Where is it usually located?
What age range?
Psx?

Answer 19

• Chondrosarcoma
• Most commonly arises in the anterior chest wall from costal cartilage or sternum
• In the third and fourth decade of life
• male predominance and most patients present with a painful, slow-growing mass; may grow to be very large and metastasize late

Question 20

Treatment of chondrosarcoma? Prognosis?

Answer 20

wide excision (4-5 cm margins) and if successful with clear margins almost always results in long-term survival

In the Mayo clinic experience, 10-year survival (Kaplan-Meier) for patients treated by wide resection was 96%; by local excision, 65%; and by palliative excision, 14%. Tumor grade, tumor diameter, tumor location, and date of operation all had a significant influence on survival. Some chondrosarcomas are relatively indolent, and recurrent/persistent disease may become apparent after many years. Long-term followup is prudent.

Question 21

Radiographically, chondrosarcoma is described how?

Answer 21

Lobulated mass with cortical destruction and its margins are poorly defined. Mottled calcifications are often present

Question 21

Chest wall defects may be reconstructed in a rigid fashion with methyl methacrylate and polypropylene plates, rib grafts, or in a less rigid fashion with muscle flaps, Marlex, or Gortex patches, to name a few options. Indications for reconstruction include?

Answer 21

Size, location, cosmesis, pulmonary mechanics.

A small defect often needs no prosthesis, whereas larger ones do. However, even large defects located beneath the scapula often do not require prosthetic closure. Large lateral or anterior defect may require protection of intrathoracic structures. Cosmetic considerations and efforts to optimize respiratory mechanics are also legitimate indications for chest wall reconstruction. Superior sulcus tumors, when resected, frequently do not need chest wall reconstruction. These defects are high and posterior and are covered by the scapula.

Question 21

What is an expansile malignancy in which calcifications develop at right angles to the cortex and are described as “sunburst” appearance?

Answer 21

Osteogenic sarcoma

Question 21

A patient has a late infection after chest wall reconstruction with methylmethacrylate mesh and a free myocutaneous flap. Imaging shows a fluid collection at the inferior portion of the mesh only.
How do you manage?

Answer 21

Resection of entire mesh and closure over drains

Treatment of this complication has 2 goals. The first and foremost is removal of all infected material. A secondary goal is to address any chest wall instability that may develop as a result of prosthesis removal.

The need to immediately reconstruct the defect is low. If a reconstruction is needed, then a bioprosthetic mesh could be utilized. Expectations should be guarded, however, since such materials can become infected when placed in a contaminated wound.

Question 22

Can skin cancers occuring on the chest wall be resected?

Answer 22

Approximately 500 new cases of malignant chest wall tumors occur yearly in the United States. Soft tissue sarcomas, chondrosarcoma, Ewing sarcomas, solitary plasmacytoma, and osteosarcoma are the most common malignant chest wall tumors. Skin cancers can also occur in the chest wall and most common are infiltrating basal cell carcinoma, malignant melanoma, and squamous cell carcinoma. If localized, the treatment of choice for chondrosarcoma, soft tissue sarcoma (of which desmoid tumor is one variant), and the group of skin cancers is resection.

Patients with osteosarcoma of the chest wall are treated similar to osteogenic sarcoma of the extremity, that being preoperative chemotherapy followed by resection.

For patients with a solitary plasmacytoma of the chest wall, the role of the surgeon is to biopsy to provide adequate tissue for diagnosis. Radiation therapy for local control is the treatment of choice, although approximately 50-60% of patients with plasmacytoma will eventually develop multiple myeloma.

Question 23

What is the thoracic surgeon’s role in Ewing sarcoma?

Answer 23

Of the estimated 2,000 new cases of malignant bone tumors seen yearly in the United States, approximately 15% (300 patients) are Ewing’s sarcoma. Since approximately 15% of Ewing’s sarcoma arise in the chest wall, only 45 patients are diagnosed with a primary Ewing’s sarcoma of the chest wall in the United States annually. Since approximately 70% of patients who present with local disease will eventually develop metastases, surgery alone is inadequate therapy for patients with localized Ewing’s sarcoma of the chest wall. The overriding factor in Ewing’s sarcoma predicting survival is the development of metastases. The five-year survival of those who develop metastases is 28%, whereas the survival of those who do not develop metastases approaches 100%. Therefore, the surgeon’s initial role in the treatment of a patient with Ewing’s sarcoma of the chest wall is to biopsy to provide adequate tissue for diagnosis.

After the diagnosis of Ewing’s sarcoma, the patient should enter a chemotherapy program which usually consists of a combination of cyclophosphamide, DTIC, doxorubicin, and vincristine.

Although there is some controversy as to whether the primary site should be irradiated or resected after chemotherapy, there is mounting evidence that the results of surgery appear superior to that of radiation therapy. However, a randomized trial of surgery versus radiation therapy after chemotherapy is sorely needed.

Question 24

How should you manage benign tumors of the sternum? Are there characteristic radiographic patterns for these tumors?

Answer 24

There is no characteristic radiographic pattern for benign sternal tumors. Benign tumors should be resected, as this allows precise diagnosis and avoids problems of potentially massive growth. A local biopsy or needle aspiration may be useful only if a lesion is felt to be metastatic on clinical grounds. Whether benign tumors of the sternum undergo malignant transformation is questionable. Since differentiation between benign and malignant lesions requires total excision and the clinical course of untreated lesions is variable, this question is academic.

Primary benign tumors of the sternum are rare. In reported series only 4% of primary sternal tumors are benign.

Question 25

Extragonadal GCTs are histologically classified as what and are usually located where?

Answer 25

classified as seminomas (dysgerminomas in women), nonseminomas (nondysgerminomas in women), and mature or immature teratomas

extragonadal germ cell tumors (GCTs) arise in midline locations, particularly in the anterior mediastinum and retroperitoneum in adults

Diagnosis centers on distinguishing between metastatic testicular germ cell tumors and other mediastinal tumors.

Scrotal exam and ultrasound are mandatory.

Nonseminomatous GCTs are associated with elevations in serum alpha-fetoprotein (αFP) and/or beta-human chorionic gonadotropin (ß-hCG) in over 80% of cases.

Histologic diagnosis is made from CT guided or more invasive biopsies. Mature teratomas of the mediastinum contain well-differentiated histologic elements consisting of tissue originating from ectoderm, mesoderm, and endoderm germinal layers. Mixed tumors containing other germ cell elements should be treated as nonseminomatous tumors.

Question 26

How do manage extragonadal GCTs?

Answer 26

Treatment of germ cell tumors varies with the histologic type of tumor.

Mature teratomas are generally benign and grow slowly. Resection is curative and can be performed via sternotomy, thoracotomy, or, occasionally, thoracoscopic techniques. Mature teratomas are resistant to chemotherapy and radiation therapy.

Immature teratomas are treated as nonseminomatous tumors with a combination of platinum-based chemotherapy and surgical resection. The optimal timing of chemotherapy in relation to surgery is controversial. Nonseminomatous tumors are treated with several platinum-based regimens, and resection of residual masses is common.

Seminomas are sensitive to cisplatin-based chemotherapy. The treatment of residual masses is controversial. Some advocate observation of masses 3 cm or less with PET-CT scans and resection of larger masses after tissue confirmation of residual disease. Radiation therapy is reserved for patients with seminomas who are unable to tolerate chemotherapy.

The prognosis for seminomatous tumors is far more favorable than for nonseminomatous tumors (90% vs. 40-45% overall survival at 5 years).

Question 27

Sclerosing or fibrosing mediastinitis with extensive fibrous tissue causes symptoms by compression, encasement, or invasion of mediastinal structures. What is it usually caused by? What’s the pathogenesis?

Answer 27

Most cases of fibrosis mediastintis in the United States are felt to occur secondary to histoplasmosis infection.

The exact pathophysiologic mechanism of chronic mediastinitis is unknown. The damage is believed to be due to antigen-mediated fibrosis or a delayed hypersensitivity reaction.

Primarily low-pressure structures in the middle mediastinum such as the SVC, azygos vein, innominate vein, pulmonary veins, and pulmonary arteries are most often involved.

Question 28

Healthy 50-year-old man presents to the emergency department with atypical posterior chest pain. He has no significant medical history and is a lifelong non-smoker. CT image below. Next step? Differential?

Answer 28

thoracoscopic surgical biopsy

chief differential diagnosis is between metastatic disease and mediastinal lymphoma

Securing a tissue diagnosis is the first priority for the described patient.

As with all lymphomas, distinguishing between the non-Hodgkin’s and Hodgkin’s varieties is important because the treatment regimens are different. This patient’s biopsy confirmed primary mediastinal large B-cell lymphoma. This form of lymphoma is aggressive and it can be associated with the presence of Reed-Sternberg cells. Immunohistochemistry and flow cytometry are required to distinguish this lymphoma from nodular sclerosing Hodgkin’s lymphoma and large cell lymphoma of the mediastinum. Presently, combined modality therapy with radiation therapy plus cyclophosphamide, adriamycin, vincristine, and prednisone (R-CHOP) is considered the standard of care for stage I disease.

Percutaneous needle biopsies may be useful for diagnosis, but fine needle aspiration has limited utility as it provides only cellular material useful for cytologic analysis. A major limitation of fine need aspiration is that architectural information is not provided. Core needle biopsies may sometimes resolve this shortcoming, but generous core samples cannot always be taken because of access challenges or nearby vital structures. This was the case with the patient described here. Therefore, a surgical biopsy is indicated as it will provide adequate tissue for all required studies and result in a definitive diagnosis. The patient’s pain does not suggest aortic pathology and the image shows abnormalities limited to the mediastinum.

Cytoreduction of mediastinal lymphomas is inappropriate.

Question 29

Major physiologic alterations accompany transnasal insertion of a flexible bronchoscope and subsequent airway stimulation:
How are the following parameters affected?
* pO2
* airway resistance
* forced expiratory volume in one second (FEV1)
* functional residual capacity

Answer 29

pO2 drops an average of 1-20 mmHg, and has been shown to drop by as much as 60mmHg in individual patients. This may be secondary to development of intrapulmonary shunt, ventilation-perfusion mismatch, occlusion of a lobar bronchus, or bronchospasm. Transcutaneous O2 monitoring is a useful adjunct to safe performance of flexible fiberoptic bronchoscopy, particularly as it allows the operator to determine when supplemental O2 therapy is necessary.

Insertion of a bronchoscope results in a decrease in tracheal cross-sectional area of 10%- 15%, while intubation with an endotracheal tube followed by insertion of a flexible bronchoscope reduces tracheal cross sectional area to 30% of normal. These actions result in an increase in airway resistance by a factor of two to three.

Consequently, patients will experience a reduction in forced expiratory volume in one second (FEV1) and forced inspiratory flow.

In addition, there will be a transient increase in functional residual capacity. All values return to normal following removal of the flexible bronchoscope.

Flexible fiberoptic bronchoscopy has become the primary tool used in investigating pulmonary neoplasms and infectious disorders. Its documented accuracy in diagnosing endobronchially visible carcinomas exceeds 90%, while nearly 50% of non-endobronchially visible cancers can also be diagnosed using bronchoscopically directed biopsy and cytologic techniques. Diagnostic yield in diffuse lung disease approaches 80% in many centers. The overall complication rate, excluding patients who undergo transbronchial biopsy, is less than 0. 1%, with a death rate of only 0.0 1%.

Question 30

As the rigid esophagoscope is advanced through the distal esophagus toward the esophagogastric junction, what maneuver is appropriate for the patient’s head/neck positioning?

Answer 30

Lower the patient’s head and turn it toward the right.

Despite the improved technology of flexible fiberoptics, rigid esophagoscopy remains a valuable tool for the esophageal surgeon, it permits removal of foreign bodies with greater ease, provides larger biopsies, and allows more direct assessment of stenoses. Safe rigid esophagoscopy, however, requires a knowledge of esophageal anatomy and appropriate repositioning of the patient’s head during the procedure to allow adjustment in the direction of the instrument as it is advanced. The distal esophagus normally courses anteriorly and to the left as it passes through the diaphragmatic hiatus toward the esophagogastric junction. Therefore, in advancing the esophagoscope through this area, the surgeon should lower the patient’s head (to elevate the distal end of the instrument anteriorly) and turn it toward the right (to direct the distal end of the instrument to the patient’s left). In advancing the esophagoscope through a stricture, the lumen may be assessed by gentle probing with a flexible (not rigid) gum-tipped bougie inserted through the instrument. Rotation of the rigid esophagoscope when it is already in the distal esophagus is dangerous and ill-advised.

Question 31

70-year-old woman with biopsy proven non-small cell lung cancer of the right upper lobe was scheduled for mediastinoscopy and a planned right upper lobectomy.

During the mediastinoscopy procedure a biopsy of the R4 nodes resulted in significant bleeding. Packing of the wound was initially effective, but the bleeding continued when packing was removed after 20 minutes. The best strategy to manage this complication is?

Answer 31

median sternotomy for assessment and repair of bleeding, plus indicated resection

The immediate management of bleeding that occurs during mediastinoscopy is to tamponade the bleeding area. Gauze packing, the mediastinoscope itself, or digital pressure may suffice. Patience with such local measures is successful in managing most bleeding, but if it continues then adequate surgical exposure must be obtained. Packing the mediastinoscopy wound and planned return to the operating room has been reported, but this is rarely performed and should not be the standard approach to major hemorrhage that occurs during mediastinoscopy.

The most common location for bleeding to occur is associated with dissection and biopsy of the right lower paratracheal (R4) nodes. Vessels that can be injured in this region include the azygos vein, the right main pulmonary artery, the truncus anterior segmental pulmonary artery of the right upper lobe, and the superior vena cava. The actual site of bleeding may not be readily apparent, but imaging modalities cannot help in this emergency and yet the source of bleeding must be identified and managed.

A right thoracotomy is an option for a stable patient, particularly if a median sternotomy has been done previously. Packing is left in place and the patient is repositioned for thoracotomy. Alternatively, the most versatile exposure for the area(s) of concern is via median sternotomy. All vascular structures can be accessed and repaired with this approach.

Additionally, if the patient remains stable, and if gross findings and frozen section analysis of the lymph nodes are favorable, the indicated lung resection can be performed through this approach. Only left lower lobectomy represents a challenge through an anterior sternotomy, because adequate exposure can be difficult to achieve without cardiac distortion.

Question 32

An otherwise healthy 42-year-old man complained of shortness of breath. Bronchoscopy showed a red, fleshy mass involving the right upper lobe orifice. A pediatric bronchoscope was able to be advanced past the mass and the bronchus intermedius appeared pristine, as did the middle and lower lobes. The mass was biopsied, resulting in bleeding that was controlled with iced saline lavage. The biopsy was nondiagnostic. The correct action is?

Answer 32

right upper lobe sleeve resection

Bronchial carcinoid tumors are the most common bronchial gland tumors. They frequently cause respiratory symptoms secondary to endobronchial obstruction. Approximately three quarters of bronchial carcinoids arise from the lobar bronchi; the remainder arise in either the mainstem bronchi or the distal airways. Many endobronchial carcinoids arise at points of division in the airway. A red, vascular appearance is typical, and when biopsied, brisk bleeding is characteristic.

Carcinoid syndrome associated with bronchopulmonary carcinoid tumors is rare. In contrast to carcinoid tumors of the gut, however, manifestation of symptoms does not require liver metastases. The tumors are thought to be part of the spectrum of neuroendocrine tumors arising from the amine precursor uptake decarboxylase (APUD) cell line. The least aggressive tumors are “typical” bronchial carcinoid tumors; the most aggressive are small cell carcinomas of the lung. Intermediate in this spectrum are “atypical” carcinoids and large cell neuroendocrine carcinomas. Approximately 90% of bronchial carcinoids are of the typical variety. The atypical variants demonstrate increased cellularity, mitotic figures and pleomorphism.

Question 32

What are the principles of resection for Adenoid cystic carcinoma of the trachea?

Answer 32

Adenoid cystic carcinoma, previously called cylindroma, is a low-grade cancer that presents with hemoptysis or wheezing. They typically are treated by resection of the involved tracheal segment with primary end-to-end anastomosis. Delayed diagnosis is common, and there is a tendency for this tumor to extend submucosally proximal and distal to the gross tumor. Perineural invasion is also common. During attempted resection, frozen section analysis of the resected margins may be positive despite generous gross resection margins. Almost all patients should receive radiation therapy after resection. If the surgical margins are positive despite attempting aggressive resection, it is better to leave microscopic tumor behind than to re-resect and risk excessive anastomotic tension.

Question 33

Which tracheal tumor commonly presents with extensive proximal and distal submucosal spread?

Answer 33

adenoid cystic carcinoma

Question 33

Do bronchial carcinoid tumors require hepatic mets to cause carcinoid syndrome?

Answer 33

Carcinoid syndrome associated with bronchopulmonary carcinoid tumors is rare. In contrast to carcinoid tumors of the gut, however, manifestation of symptoms does NOT require liver metastases. The tumors are thought to be part of the spectrum of neuroendocrine tumors arising from the amine precursor uptake decarboxylase (APUD) cell line. The least aggressive tumors are “typical” bronchial carcinoid tumors; the most aggressive are small cell carcinomas of the lung. Intermediate in this spectrum are “atypical” carcinoids and large cell neuroendocrine carcinomas. Approximately 90% of bronchial carcinoids are of the typical variety. The atypical variants demonstrate increased cellularity, mitotic figures and pleomorphism.

Question 34

What are the least aggressive and most aggressive types of bronchial carcinoid tumors?

Answer 34

The least aggressive tumors are “typical” bronchial carcinoid tumors; the most aggressive are small cell carcinomas of the lung.

Intermediate in this spectrum are “atypical” carcinoids and large cell neuroendocrine carcinomas. Approximately 90% of bronchial carcinoids are of the typical variety. The atypical variants demonstrate increased cellularity, mitotic figures and pleomorphism.

Question 35

A 50-year-old woman underwent tracheal resection and reconstruction for a postintubation laryngotracheal stenosis located 1 cm below the bottom of the cricoid. Three cm of airway were resected. On postoperative day 6 she developed stridor, a low-grade fever, and redness and swelling of the collar incision. An urgent neck CT demonstrates some air and fluid around the anterior tracheal anastomosis as well as soft tissue edema.
What is likely happening?
The best next step is?

Answer 35

This is likely a partial separation of the tracheal anastomosis. It is the most feared complication early after tracheal resection. Usually the posterior/membranous trachea will remain intact.

Limited exploration of the anterior wound allows drainage of the infection and placement of a tracheostomy tube or a T-tube through the anastomosis temporarily stents and maintains the airway and leads to a prompt recovery. After several months the tracheostomy tube or T tube can be removed and the defect will heal without the need for further tracheal surgery. Risk factors for tracheal dehiscence include redo surgery, diabetes, resections over 4 cm, very young patients, and a laryngotracheal anastomosis.

Other anastomotic complications include granuloma formation along the suture line, gradual stenosis leading to anastomotic failure, and necrosis of the anastomotic repair ultimately leading to either separation or necrosis depending upon the time course. Most partial anastomotic separations occur anteriorly and lead to a neck wound infection, which often becomes clinically obvious. Typically soft tissue swelling further compromises the anastomosis and often leads to laryngeal edema and vocal cord edema. Typically the airway is compromised and dyspnea and/or stridor result. Prompt diagnosis is essential.

Because this anastomotic complication can lead to severe airway compromise, prompt management of both the infection and airway are essential. This is almost always best done in the operating room under ideal conditions.

Bedside flexible bronchoscopy certainly could confirm the diagnosis, but it can further compromise an already tenuous airway.

Placing a tracheal stent would be very challenging in this situation, it would not address the infection, and it would likely lead to a unrepairable airway due to granulation formation at the top and bottom of the stent.

Revision of a tracheal anastomosis in the face of separation and infection is an ill-advised maneuver.

Question 36

What are risk factors for tracheal dehiscence after resection and anastomosis?

Answer 36

Risk factors for tracheal dehiscence include redo surgery, diabetes, resections over 4 cm, very young patients, and a laryngotracheal anastomosis.

Question 37

A 15-year-old patient had a tracheostomy eight days ago. He remains on a ventilator recovering from ARDS (adult respiratory distress syndrome) and has 50 cc of blood suctioned from the tracheostomy tube. The appropriate response is?

Answer 37

This should include a careful inspection of the anterior tracheal wall and requires deflation of the tracheostomy cuff and removal of the tube momentarily. In most cases a T-I fistula will not be present, but identification justifies emergent operation for ligation of the artery or, less frequently, repair. Exsanguinating bleeding may be controlled by overinflating the tracheostomy cuff and if unsuccessful then digital pressure through the tracheostomy site to tamponade the innominate artery against the sternum. In such an instance, the patient is reintubated orally.

Question 38

Factors that predispose to TI fistula?

Answer 38

low tracheostomy stoma, chronic over-inflation of the tracheostomy cuff, improper positioning of the tracheal stoma, localized sepsis, and an abnormally horizontal or high innominate artery

Bleeding from a tracheostomy site in the first 24 hours is generally related to failure of surgical hemostasis (i.e., inadequate ligation of thyroid isthmus or anterior jugular vein). Bleeding weeks or months postoperatively is usually due to tracheobronchitis or granulation tissue around the stoma or at sites of repeated irritation while suctioning. The overall incidence of bleeding following tracheostomy has been estimated at 2-3%. If more than 10cc of bleeding occurs between post operative days 3 - 21 then one must consider a tracheo-innominate (T-I) fistula. The incidence of T-I fistulas is 0.3 - 0.7% following tracheostomy.

Question 39

Bronchoscopic examination in a 52-year-old man shows high-grade narrowing of the left mainstem bronchus by an irregular mass extending from the spur of the tracheal carina over a total length of 1.5 cm. A biopsy of the mass confirms squamous cell carcinoma. CT shows that the tumor does not extend into adjacent structures. Mediastinal lymph nodes are not enlarged. The best management is?

Answer 39

right thoracotomy, carinal resection and reconstruction

The bronchoscopic and radiographic descriptions suggest that this tumor is resectable. Endoscopic resection, brachytherapy, laser ablation, or radiotherapy are inadequate treatments. None of these is appropriate unless the patient is not a candidate for resection.

Sleeve resection of the upper lobe is not plausible in this case because the lower lobe bronchus is short and cannot be mobilized to reach beyond the proximal extent of tumor at the carina. Since the mass involves the carinal spur, such a reconstruction cannot have a negative margin. The carina must be resected. Median sternotomy and transpericardial dissection provides good access to the carina, but left pneumonectomy is neither indicated nor desirable. Preserving the left lung appears attainable given the measurements of the tumor. Right thoracotomy allows exposure of most of the left mainstem bronchus for carinal resection and reconstruction.

Question 40

The fundamental pathologic abnormality in achalasia is thought to be?

Answer 40

A loss of control at the postganglionic level of nonadrenergic and noncholinergic inhibitory nerves seems to be the basic defect.

The intrinsic motor neurons of Auerbach’s plexus between the inner circular and outer longitudinal muscular layers are either reduced in number or absent. Changes are most prominent in the distal portion of the esophagus and lower esophageal sphincter. Histopathologic changes also exist in the preganglionic nerve axons and the brain stem nuclei. Although the esophageal smooth muscle shows variable and nonspecific changes, the gross appearance of the distal esophageal muscle and lower esophageal sphincter is usually normal.

Question 41

Is tere a correlation between the endoscopic grade of esophagitis and the severity of symptoms?
What is the best method for diagnosing GERD?

Answer 41

No. The correlation between the endoscopic grade of esophagitis and the severity of symptoms is poor.

The best method for diagnosing abnormal gastroesophageal reflux is prolonged ambulatory pH monitoring. Drug-induced esophagitis cannot be reliably distinguished from reflux esophagitis, either by its endoscopic appearance or by histologic examination of the inflamed esophageal mucosa.

Manometry may be helpful in confirming a lower esophageal sphincter of short length or abnormally low pressure, but sphincter pressure per se is not diagnostic of reflux. Resting tone in the lower esophageal sphincter varies greatly, both in normals and in patients with reflux esophagitis. Normal pressures range from 10 to 25 mmHg.

A positive Bernstein test is indicative only of an acid-sensitive esophagus, and the incidence of both false-positives and false-negatives with this test limits its diagnostic utility.

On a barium swallow, the majority of reflux patients will have a demonstrable hiatal hernia, and reflux can be stimulated by a variety of postural maneuvers. However, both findings can also be observed in many normal patients and thus, are not diagnostic of pathologic reflux. The classical presentation is heartburn, substernal burning, and regurgitation aggravated by postural changes. While these symptoms occur in a high percentage of reflux patients, there are some who will be entirely asymptomatic despite endoscopic findings of severe esophagitis.

Question 42

A patient with a documented cervical esophageal perforation was taken to the operating room. The site of perforation could not be identified despite cervical exploration. The next step should be to?
What are some risk factors?

Answer 42

Closed drainage and parenteral antibiotics as long as no distal obstruction.

Elderly patients with degenerative cervical disc disease, bone spurs and decreased neck mobility are at particular risk.

Closure of the wound and treatment of a known cervical esophageal perforation with parenteral antibiotics alone predisposes the patient to development of a neck abscess and, possibly, mediastinitis.

If a site of perforation cannot be located during neck exploration, the patient is unlikely to benefit from an esophagoscopy to try to locate the site and repair it because the perforation is likely quite small. Esophagoscopy may cause more harm (it is the most often cause of this complication). A right thoracotomy is rarely indicated for treatment of a cervical esophageal perforation unless mediastinitis occurs and mediastinal drainage is required. There is no reason to perform a cervical esophagostomy to divert saliva following cervical esophageal perforation because healing occurs in the vast majority of patients.

Question 43

What is the most often cause of cervical esophageal perforation?

Answer 43

Cervical esophageal perforation results most often from endoscopic instrumentation.

Question 44

A 50-year-old woman with scleroderma presents with dysphagia and regurgitation. Esophageal manometry is expected to show which of the following characteristics of the body and lower esophageal sphincter (LES)?

Answer 44

Low amplitude contractions of the body; Hypotensive LES

Scleroderma is a collagen vascular disease affecting the smooth muscles of the esophagus. It is an example of a secondary esophageal motility disorder. It is characterized by loss of smooth muscle function, and can lead to dysphagia, regurgitation and heartburn, in addition to a plethora of other symptoms attributable to diffuse involvement of the gastrointestinal tract. Typical characteristics of scleroderma seen on stationary manometry include loss of esophageal body peristalsis in association with a hypotensive lower esophageal sphincter (LES).

Question 45

Primary esophageal motility disorders include the following. Describe their manometry findings.

1) Achalasia

2) “Nutcracker” esophagus

3) Hypertensive LES

4) Diffuse esophageal spasm, characterized by simultaneous esophageal body contractions (>20% of wet swallows) in association with intermittent normal peristaltic sequences. The LES is generally normal, though may be hypertensive

Answer 45

1) Achalasia, characterized by esophageal aperistalsis associated with a hypertensive, poorly relaxing LES and an elevation of the baseline esophageal body pressure (“pressurization”)

2) “Nutcracker” esophagus, characterized by hypertensive peristaltic sequences and a normal LES

3) Hypertensive LES, characterized by high LES resting pressure in association with normal esophageal body function

4) Diffuse esophageal spasm, characterized by simultaneous esophageal body contractions (>20% of wet swallows) in association with intermittent normal peristaltic sequences. The LES is generally normal, though may be hypertensive

Question 46

A patient with acid reflux had an endoscopic esophageal biopsy showing columnar specialized epithelium. An anti-reflux procedure will provide what benefits?

Answer 46

Performing an anti-reflux procedure should decrease the gastrointestinal reflux of both acid and pancreatic-duodenal secretions into the esophagus. Each is believed responsible for the changes seen in Barrett’s esophagus.

Cessation of the reflux stops progression of Barrett’s mucosa and should result in relief of symptoms and healing the coexisting esophagitis. However, most studies do NOT demonstrate complete resolution of the abnormal mucosa.

Of great importance is the issue of progression of Barrett’s after antireflux surgery. Several studies now document that surgery is associated with a lower incidence of dysplasia and adenocarcinoma than medical therapy. However, the development of adenocarcinoma has been reported in patients after effective antireflux surgery. A complicating factor in follow-up surveillance analyses is that genetic alterations leading to the development of dysplasia and adenocarcinoma may have already occurred prior to antireflux surgery and may not necessarily represent progression of disease. In a Mayo study, 3 of 133 patients with Barrett’s developed adenocarcinoma following antireflux surgery. Surveillance is still needed.

Question 47

A 65-year-old woman had a distal esophageal tumor resected by a transhiatal approach. Several months later she complains of perspiration, tremors, intermittent diarrhea and cramping following meals.
What is happening?
How do you manage?

Answer 47

Dumping syndrome.

The therapy for dumping begins with dietary modifications.
* Low carbohydrate diets are prescribed.
* Meals should be frequent and small.
* Reducing liquids limits gastric distension and improves symptoms by slowing emptying of the stomach.
* Fiber supplementation may also help to slow transit time.

In difficult cases:
* Somatostatin or its long-acting synthetic analog, octreotide, can be used. Somatostatin blocks insulin release and counters many of the symptoms due to inappropriate release of gut hormones.

Other functional problems sometimes noted following esophagectomy include delayed gastric emptying and gastric outlet obstruction. These complications are possibly related to the vagotomy inherent during esophagectomy, which disrupts relaxation of the pylorus during meals. Prokinetic agents such as metoclopramide, cisapride, bethanechol, erythromycin and domperidone have all been used with varying success to improve gastric emptying when it is delayed.

Dumping refers to a constellation of symptoms that may develop after esophageal or gastric resection. Dumping is more often seen in women and younger patients. Two dumping syndrome patterns have been described. Early dumping symptoms develop within the first hour of eating and include palpitations, flushing, dizziness, syncope, cramping and diarrhea. Late symptoms are less common and are more systemic in nature including increased sweating, tremors, somnolence and difficulty concentrating. Most patients suffer from early symptoms but only a few patients suffer from both early and late symptoms. Liquids and carbohydrates are often mediators of this syndrome, possibly due to the inappropriate release of gut-related hormones in response to early emptying of the stomach.

Question 48

What are the proto-oncogenes that are known to affect the growth of esophageal carcinomas?

Answer 48

• Epidermal growth factor receptor (EGFR)
• Transforming growth factor (TGF-a)
• C-erb
• Cyclin-D

Of note, no significant correlation between p53 abnormalities and clinicopathologic parameters or survival has been consistently reported.

Question 49

Surgical approaches to a squamous cell carcinoma at 24 cm from the incisors adjacent to the carina on CT scan.
What are the surgical principles at play?
What is your best approach and why?

Answer 49

Mid- and upper carcinomas of the esophagus can abut the airway and the aorta. For the lesion described, a preoperative bronchoscopy is mandatory. Esophageal carcinoma that invades surrounding structures it is defined as T4 by the new AJCC staging criteria. Most surgeons consider a T4 tumor to be inoperable, as safe or complete resection is unlikely. Resection of a lesion at this level requires generous exposure for mobilization of the airway, including the carina. A generous incision also minimizes injury to surrounding structures.

The combined McKeown esophagectomy (right thoracotomy, laparotomy, trans-cervical anastomosis) is optimal for the lesion described. Initial right thoracotomy reveals the entire length of the thoracic esophagus and permits assessment of resectability. If vital structures are invaded, then the procedure can be aborted without having divided the esophagus or committed to a major reconstruction.

Question 50

A 63-year-old man with a prior history of significant alcohol and tobacco use underwent an esophagogastroduodenoscopy. This revealed a 0.5 cm raised mucosal lesion in the esophagus at 30 cm from the incisors. The biopsy was concerning for at least squamous carcinoma in situ. Endoscopic ultrasound revealed no invasion of the muscularis propria and no malignant appearing paraesophageal nodes. Endoscopic mucosal resection (EMR) was performed and final pathology revealed squamous cell carcinoma with lymphovascular invasion invading the submucosa (T1b) with close but negative margins. The best next step is?

Answer 50

T1b squamous cell cancers of the esophagus have a high risk of lymph node metastases (~ 25%) and require esophagectomy to maximize the chance of local control.

Radiofrequency ablation is used to treat Barrett dysplasia. It has no role for treating positive or close margins after endoscopic resection of carcinoma.

Higher histologic grade, lymphovascular invasion, and invasion into the submucosa are associated with increased risk of lymph node metastasis. Surveillance endoscopy is sufficient for T1a cancers that are resected endoscopically with negative margins.

Question 51

During a transhiatal esophagectomy the anesthesiologist notes an increase in ventilator tidal volume requirements. The surgeon notes increased amounts of air within the mediastinal tissues.
What happened?
The first intervention should be to?

Answer 51

Disruption from vigorous dissection of the esophageal tumor in this area may result in a tear of the membranous trachea.

Should this occur the single lumen endotracheal tube cuff should be deflated and the tube guided into the left mainstem bronchus under bronchoscopic guidance. With this maneuver the airway is controlled.
A right thoracotomy will expose the area of injury along the distal trachea and left mainstem for repair.
The anesthesiologist would reduce tidal volume after positioning the endotracheal tube.

Intraoperative complications of transhiatal esophagectomy are rare. However, when they occur they relate to the blind dissection in the mediastinum. A tumor in the upper two-thirds of the esophagus may be adherent to the azygous vein. With blind dissection azygous vein disruption can occur. Visualization of the bleeding area is unlikely. Packing the upper mediastinum with sponges may allow time to perform a right thoracotomy to ligate the azygous vein. Tumor may also be adherent to the posterior wall (the membranous portion) of the trachea particularly at the carinal-left mainstem junction.

The nasogastric tube has no significant function. Bilateral tube thoracostomy is not absolutely required as the possibility of a tension pneumothorax with an open mediastinum is low.

Question 52

The diagnosis of acute rejection after lung transplantation is made by what findings?

Answer 52

Acute rejection of the lung may be localized or diffuse. The histologic findings of acute rejection are characterized by the perivascular infiltration of mononuclear cells. Although bronchoscopy with bronchoalveolar lavage can demonstrate increased numbers of lymphocytes, viral cultures are necessary to exclude the possibility of viral pneumonitis.

Bronchoscopy with transbronchial biopsy of at least three sites in the involved lobe is both sensitive and specific for the diagnosis of acute rejection. Transbronchial biopsies can also reveal the cytopathic changes characteristic of viral pneumonitis. Chest computerized tomographic scans can localize the involved areas, but the radiographic appearance of rejection can mimic infection. Similarly, a decreased forced expiratory flow volume (FEV1) is a finding common to both infection and rejection.

Question 53

From a purely technical standpoint, what side lung transplants are preferred?

Answer 53

From a purely technical standpoint, single lung transplants on the left side are preferred. It is easier to obtain a larger cuff for pulmonary veins on the left side and the recipient’s bronchus is longer on the left.

Question 54

Which of the following is a definite indication for bilateral lung transplantation? Why?
* alpha-1 antitripsin deficiency
* congenital adenomatoid malformation
* cystic fibrosis
* lymphangioleiomyomatosis
* pulmonary hypertension

Answer 54

CF. The only generally accepted recipient criterion for bilateral lung transplantation is septic lung disease (including cystic fibrosis) which predisposes recipients to graft infection if a native lung is left in place.

Lung transplantation is an accepted therapy in the management of end-stage lung disease. Most patients can be treated successfully with a single lung transplant. Initial concerns that unilateral transplantation in emphysematous patients (including those with alpha-1 antitrypsin deficiency) would promote severe ventilation-perfusion mismatching were unfounded. Results for unilateral transplantation for fibrosis, pulmonary hypertension, and lymphangioleiomyomatosis are similar to those for emphysema.

Question 55

Calcineurin acts on which biochemical targets?

Answer 55

Calcineurin is a serine-threonine phosphatase, principally important in the signaling of T cell activation. An antigen-presenting cell stimulates T-cell surface proteins to increase intracellular calcium, which is bound by calmodulin, an intermediate messenger, which then activates calcineurin. This binding facilitates dephosphorylation of the nuclear factor of activated T cells (NFATc). The dephosphorylated NFAT molecule then translocates to the cell nucleus and stimulates transcription of the interleukin-2 (IL-2) gene. This, in turn, stimulates T cell growth and differentiation with assistance of helper T-cells. Calcineurin antagonists (e.g., cyclosporin, tacrolimus) act to prevent NFAT dephosphorylation and nuclear translocation, thereby decreasing IL-2 production.

Toll-like receptors are pattern recognition receptors on macrophages and dendritic cells that activate immune cell responses in response to detection of antigens present on invading microbes.

The T cell-receptor/CD3 complex is central to antigen presentation/recognition on the surface of T cells, which stimulates cellular proliferation, differentiation, cytokine production, and/or activation-induced cell death.

CD28 and CTLA-4 are also important regulators of the T cell response to antigen presentation, with proliferative and inhibitory effects, respectively.

IL-2 receptors span the lymphocyte cell membrane and function to facilitate internal signaling leading to T-cell proliferation.

Question 56

How does PGD affect lung transplants long-term?

Answer 56

Primary graft dysfunction (PGD) is the clinical manifestation of ischemia/reperfusion lung injury and is a major cause of early morbidity and mortality after lung transplantation. Lung recipients classified as having PGD have worse long-term lung function and carry an increased chance of developing bronchiolitis obliterans syndrome (BOS), the manifestation of chronic rejection. PGD affects 10-25% of lung transplants. The International Society of Heart and Lung Transplantation proposed a standard definition of this graft dysfunction syndrome in order to quantify the problem and provide a framework for research.

A grading system for primary graft dysfunction is used in the early transplant period. Measurements are taken at several time points in the first 72 hours after transplantation. The system evaluates two factors 1) the presence of bilateral infiltrates on CXR yes or no and 2) The PaO2/FiO2 ratio. No infiltrate and any ratio is Grade 0. Bilateral infiltrates on CXR is Grade 1 (PaO2/FiO2>3), Grade 2(200-300), or Grade 3, (<200). This patient’s CXR demonstrates infiltrates and the pO2/FiO2 ratio (oxygenation index) is 213. This correlates with a primary graft dysfunction score of Grade 2, which represents a moderate increased risk for future immunologically mediated lung dysfunction. Initial therapy is supportive and focuses on appropriate immunosuppression, avoidance of fluid overload and avoidance of concomitant ventilator associated lung injury.

The use of cardiopulmonary bypass is common and some have actually suggested an induced immunosuppressive effect. In the setting of a transplant, this might be seen as protective. The same is true for transfusion, and the amount transfused in this case is not extraordinary for a bilateral transplant on CPB. As for mechanical ventilation, most recipients are still intubated and weaning 24 hours after operation, and an intubation time of a couple days does not predict future lung dysfunction.