Thoracic Surgery

Question 0

Thoracic Diaphragmatic Anatomy

Answer 0

During expiration the right diaphragm rises to level of the nipple (T4) and the left rises to one rib space lower.

The right diaphragma flattens to level of the 11th rib; the left flattens to the level of the 12th rib.

The IVC hiatus lies at the level of T8 (includes branches of the R phrenic)
The Esophageal aperaure is at the level of T10 (includes the L/R vagal trunks)
The Aortic aperature is at the level of T12 (includes azygous and thoracic duct)

Question 1

Cervicoaxillary Canal

Answer 1

The cervicoaxillary canal is bounded by the first rib inferiorly, the clavicle superiorly, and the costoclavicular ligament medially.

Includes the subclavian vein and artery and the brachial plexus

Brachial plexus is composed of nerve roots C5-Superior trunk (C5-C6), Middle trunk (C7), and Inferior trunk (C8-T1)

Question 2

Thoracic surface anatomy

Answer 2

Right manubrial border; Right brachiocephalic vein, origin of superior vena cava, innominate artery

Manubrium; Aortic arch and origin of great vessels, left brachiocephalic vein

Left manubrial border; Left common carotid and left subclavian vessels

The angle of Louis:
Right hemithorax-azygous vein joins SVC
Midline-thoracic duct crosses the midline
Left hemithorax-aortopulmonary window

Left third costal cartilage; origin of aorta and pulmonary artery
Right third costal cartilage; SVC empties into the RA

Right oblique fissure courses anteriorly at the level of the fifth rib.
The posteriorly left oblique fissure starts at a level between the third and fifth ribs and ends anteriorly at the level of the fifth rib.
The horizontal fissure starts anteriorly at the fourth costal cartilage and joins the oblique fissure a the level of the fifth rib.

Question 3

Endoscopic Ultrasound

Answer 3

Used for staging of esophageal cancer.
Four normal endoluminal findings:
1. Upper esophageal sphincter at the cricopharyngeus (15 cm)
2. Aortic arch (indentation on the left anterolateral wall) (23 cm)
3. Left atrium (wavelike pulsations in anterior wall of distal esophagus)
4. Lower esophageal sphincter (35-40 cm)

The esophagus is seen in 5 layers.
Hyperechoic is white, hypoechoic is black
1. First layer (hyperechoic) = epithelium and lamina propria
2. Second layer (hypoechoic) = muscularis mucosa
3. Third layer (hyperechoic) = submucosa
4. Fourth layer (hypoechoic) = muscularis propria
5. Fifth layer (hyperechoic) = paraesophageal tissue

Main advantage over CT is “differentiation of T stage,” especially between the T3 and T4 stages.
The accuarcy of EUS for staging of regional lymph nodes is 70-80%
Most EUS errors are either understaging T0 or T1 or overstaging T2.

Question 4

Contraindications to esophagoscopy

Answer 4

Recurrent nerve paralysis
Esophageal varices with esophagitis
Esophageal diverticulum
Aortic aneurysm (pulsatile compression)
Corrosive strictures
Kyphoscoliosis

Question 5

Standard acid reflux test

Answer 5

Tests LES competence
300 cc acid infused in the stomach
pH less than 4 is evidence of reflux
Acuracy 81%, Sens 59%, Spec 98%

Question 6

Esophageal Manometry (Indications, findings)

Answer 6

Indicated for symptoms of dysphagia, chest pain, heartburn, or regurgitation. Diseases such as achalasia, DES, nutcracker esophagus, hypertensive LES.

Mechanically defective sphincter:
Average LES pressure

Question 7

Evaluation of GE Reflux with 24 hr motility/pH monitoring

Answer 7

24 hr motility monitoring:
Esophageal motility is the most important factor in clearance of gastric reflux.
Efficient peristaltic contractions have an amplitude of >30 mmHg.
Duration of reflux proportional to number of efficient contractions.
Esophageal contractility deteriorates with increasing severity of mucosal injury.

24 hr pH monitoring:
Probe positioned 5 cm above GE junction.
Stop H2 blockers 48 hrs prior/PPI 2 weeks prior.
Evaluation:
Time pH less than 4 measured as a percentage of total, upright and supine monitored time.
Frequency of reflux episodes
Duration of reflux episodes
Duration of longest episode of reflux

Question 8

What is the most common site of distant metastasis for NSCLC?

Answer 8

Brain, Imaging should include CT brain and Bone scan for advanced cases.

Question 9

What is the most specific predictor of post operative pulmonary complications related to lung resection?

Answer 9

Measurement of maximal oxygen consumption (VO2 max). Patients with VO2max greater than 15 mL/kg/min can undergo surgical resection with an acceptably low mortality rate. Patients with postoperative FEV1 and DLCO less than 40% predicted and VO2max less than 15 mL/kg/min have a very high risk of postoperative com- plications and/or death.

Question 10

What is the cell site of origin for BAC or Adenocarcinoma in situ of the lung?

Answer 10

Type II pneumocyte (Clara Cell)

Question 11

Tumors that invade the chest wall, diaphragm, phrenic nerve, parietal pleura, pericardium, or main stem bronchus less than 2 cm from the carina, but without involvement of the carina, are?

Answer 11

T3

Question 12

Tumors that invade the contents of the mediastinum (i.e., heart, great vessels, trachea/carina, recurrent largyngeal nerve, esophagus) or vertebral body are?

Answer 12

T4

Question 13

Tumors 7 cm or larger, tumors that result in obstructive atelectasis or pneumonitis of the entire lung, and 2 or more tumors within the same lobe are?

Answer 13

T3

Question 14

2 or more tumors in different ipsilateral lobes?

Answer 14

T4

Question 15

Patients with Tumors in the contralateral lung are deemed to have?

Answer 15

M1 Disease

Question 16

Treatment of MAI or atypical mycobacterial infection?

Answer 16

Indications for operation include concern for underlying cancer, lesions that are growing or refractory to antibiotics, and persistently positive sputum despite antibiotics (particularly clarithromycin, ethambutol, and rifampin).

The primary goal of treatment is symptom improvement and sputum conversion. Elimination of gross structural lesions and focal disease may be required to achieve these goals and to restore optimal lung function. While the infection is often diffuse throughout the lung, there are often a small number of radiographically discrete areas that are amenable to resection. Ideally, resection is anatomic (lobectomy or segmentectomy), although wedge resections may be necessary if the disease is peripheral and involves multiple lobes of the lung

Atypical mycobacterial disease (“MAC” – Mycobacterium avium complex, or “MOTT” - mycobacterium other than M tuberculosis)

Two patient populations at risk: (1) middle-age women with no demonstrable lung disease, and (2) patients of both sexes with pre-existing pulmonary abnormalities.

Preoperative diagnosis is not always possible, and organism identification (M konsasii , m szulgai, M. xenopi. M. chelonae, others) requires DNA hybridization.

Postoperative morbidity is considerable in most published reports and some authors advocate staple line reinforcement with PTFE or pericardial strips. If completion pneumonectomy is required, the bronchial stump should be covered with a viable tissue flap. Both preoperative and protracted postoperative antibiotics are essential, and nutritional supplementation is crucial in many cases.

Question 17

Most common primary histology for patients evaluated for pulmonary metastasis?

What is the second most frequent source of metastases to the lungs?

Answer 17

Colorectal carcinoma (35-45% five year survival with resection)

Sarcoma (in as many as 50% of patients, the lungs are the only site of metastatic disease)

Question 18

What is the strongest predictor of survival with pulmonary metastasis?

Answer 18

Complete resection.

Besides histology, factors associated with improved survival in patients undergoing PM include a prolonged disease-free interval from the time of resection of primary tumor to the appearance of pulmonary metastases, and a lower number of pulmonary metastases.

Repeat PM may be required when there are isolated recurrences in the lungs. Of patients undergoing PM, 40% to 80% will suffer a pulmonary recurrence. Repeat PM has been shown in the International Registry and several sub- sequent databases to afford a long-term survival advantage in patients that qualify for repeated procedures.

Question 19

TEF is the most common anomaly of the trachea.
What is the most commonly used classification (by Gross)?
Which is the most common?

Answer 19

• Type A (8%): esophageal atresia without TEF
• Type B (1%): esophageal atresia with proximal TEF
• Type C (87%): esophageal atresia with distal TEF (Most Common)
• Type D (1%): esophageal atresia with proximal and distal TEF
• Type E (4%): TEF without esophageal atresia

Question 20

Describe the anatomy of Extra Lobar Sequestrations?

Answer 20

Twenty-five percent of sequestrations are extralobar (ELS), which are distinct from the remaining lung, with their own visceral pleura. They are round soft tissue masses that typically lie just above the dome of the diaphragm, with 90% found at the base of the left lung. The venous return is more often systemic (azygos, hemiazygos), with only 20% draining into the pulmonary veins. ELS are associated with other anomalies (congenital diaphragmatic hernia [CDH], congenital cystic adenomatoid malformation [CCAM], pericardial cysts, cardiac defects, esophageal achalasia), may be found in various locations (pericardium, diaphragm, below the diaphragm ret- roperitoneally), and have been known to contain malignancies.

Question 21

Describe the findings of Intralobar Sequestrations?

Answer 21

Intralobar sequestrations (ILS) comprise 75% of pulmonary sequestrations and are primarily found in the right and left lower lobes, with the most frequent location being the posterior segment of the LLL. They are cystic abnormalities located within the visceral pleural of the lung that communicate with the normal lung tissue through the pores of Kohn. Ninety-six percent of ILS will have venous drainage to the pulmonary veins. It is rarely associated with other anomalies, but may present antenatally as polyhydramnios.

Question 22

Describe the classification system of Congenital Cystic Adenomatoid Malformation (CCAM)?

Answer 22

CCAM can be classified (by Stocker) as follows:

• Type I (macrocystic, 60-70%). Large, widely-spaced, irregular cysts that are larger than 2 cm. This type is rarely associated with polyhydramnios or other anomalies. Most patients will reach term, but some are stillborn. Mediastinal shifting can be seen in 75% of patients with some associated cyanosis and grunting. Half will develop pneumonia during infancy or early childhood, but the overall prognosis is good.

• Type II (mixed, 20-40%). The cysts are smaller than 2 cm, and have the appearance of more bronchioles with increased proliferation and less mediastinal shift. Patients tend to be prema- ture or stillborn.

• Type III (microcystic, 10%). The cysts are smaller than 0.5 cm, and the mass is firmer, ap- pearing to encase the entire affected lobe (most commonly LLL). Prognosis is very poor, with life expectancy of hours after birth.

CCAM presents as neonatal acute respiratory distress with multiple air fluid levels on CXR. CT may solidify the diagnosis. Associated anomalies are pectus excavatum (most common) and cardiac and pulmonary vessel malformations

Question 23

Describe the types of Congenital Tracheal Stenosis?

Answer 23

Congenital tracheal stenosis is classified in three types (by Cantrell and Guild):

• Type 1: involves the entire trachea
• Type 2: funnel shaped stenosis of the upper, lower, or the entire trachea
• Type 3: segmental stenosis of the lower trachea

Question 24

What are the common associated findings with Congenital Tracheal Stenosis?

Answer 24

Fifty percent of cases are associated with a pulmonary vascular sling or a vascular ring, and all types may be associated with pulmonary agenesis.

Question 25

How should bleeding during Mediastinoscopy be managed?

What is the most common site for bleeding to occur?

Answer 25

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.

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 extreme cardiac distortion.

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.

Question 26

Findings of the NETT (National Emphysema Treatment Trial Research Group) trial?

Answer 26

Patients with upper lobe predominant disease were found to have decreased symptoms and improved exercise tolerance with surgery when compared to medical therapy. Patients with homogenous distribution of disease were found to have decreased survival after LVRS.

Question 27

What does LVRS (Lung Volume Reduction Surgery) improve?

Answer 27

Multiple studies have shown that LVRS results in improved FEV1, respiratory muscle function, exercise capacity, and dyspnea

Question 28

Definition and Findings of Empyema?

Answer 28

Empyema is defined as a pleural effusion with positive bacteriologic cultures. Findings in analysis of pleural fluid include a pH 1000 IU/L.

Question 29

Tracheal blood supply and important considerations to resection?

Answer 29

Arterial inflow originates from the inferior thyroid, subclavian, supreme intercostal, internal mammary, innominate, and superior and middle bronchial arteries.

Arterial connections that provide important collateral tracheal circulation include (1) lateral longitudinal collaterals that link the lateral segmental blood supply, (2) transverse intercartilaginous arteries which connect blood supply from the right and left sides, (3) tracheoesophageal vessels, and (4) connections from the carinal nodal or bronchial arteries and the more proximal blood supply.

Tracheal blood supply is segmental and the lateral tracheal supply must be preserved to maintain airway viability. Interruption of the lateral supply by overly aggressive dissection or skeletonization of the airway must be avoided. Overaggressive efforts to improve mobility will result in a high incidence of anastomotic complications and the potential for devastating long-segment ischemic necrosis. Several maneuvers improve the surgeons ability to achieve primary repair following tracheal resection, but the circumference of proximal and distal tracheal margins should be freed up only enough for accurate and secure anastomosis completion.

Question 30

Three main subtypes of Malignant Pleural Mesothelioma?

Answer 30

Three major subcategories: epithelioid, sarcomatoid, and biphasic (mixed)

Question 31

What is the most common cause of pleural effusion in the neonatal period?

Answer 31

Congenital chylothorax

Question 32

Diagnosis of Chylothorax?

Answer 32

Diagnosis is suggested by the presence of non-clotting milky fluid in the pleural space. Triglyceride levels > 110 mg/dL are 99% diagnostic. Levels 200 mg/dL with cholesterol crystals and no chylomicrons. Chylothorax usually has a cholesterol-to-triglyceride ratio of

Question 33

Indications for surgical intervention of Thoracic Duct Leak?

Answer 33

Indications for duct ligation include:

• Average daily loss of > 1500 cc/day in adults or > 100 cc/day in children over a 5-day period despite conservative management

• Persistent leak for over 2 weeks

• Nutritional or metabolic complications

• Entrapped lung with inability to adequately drain the collection with a chest tube

• Post-esophagectomy chylothorax (given the high morbidity and mortality in these patients from immunological and metabolic imbalances)

Question 34

For patients with calculated post-resection FEV1 below the accepted safe lower limit, the best test to determine candidacy for resection is:

Answer 34

DLCO