Abstract
The following are the major muscles that will be encountered and may be divided during thoracic operations for trauma.
- Anterior Chest Wall: Pectoralis major and pectoralis minor muscles
- Pectoralis major muscle: It originates from the anterior surface of the medial half of the clavicle, the anterior surface of the sternum, and the cartilages of all the true ribs (1–7 ribs). The 5-cm wide tendon inserts into the upper humerus.
- Pectoralis minor muscle: It arises from the third, fourth, and fifth ribs, near their cartilages, and from the aponeuroses over the intercostal muscles. It inserts into the coracoid process of the scapula.
- Pectoralis major muscle: It originates from the anterior surface of the medial half of the clavicle, the anterior surface of the sternum, and the cartilages of all the true ribs (1–7 ribs). The 5-cm wide tendon inserts into the upper humerus.
- Lateral Chest Wall: Serratus anterior muscle
- Serratus anterior muscle: It originates from the lateral part of the first eight to nine ribs and inserts into the medial aspect of the scapula.
- Posterior Chest Wall: Latissimus Dorsi
- Latissimus Dorsi muscle: It originates from the spinal processes of the lower thoracic spine and the posterior iliac crest and inserts into the upper portion of the humerus.
Surgical Anatomy
The following are the major muscles that will be encountered and may be divided during thoracic operations for trauma.
Anterior Chest Wall: Pectoralis major and pectoralis minor muscles
Pectoralis major muscle: It originates from the anterior surface of the medial half of the clavicle, the anterior surface of the sternum, and the cartilages of all the true ribs (1–7 ribs). The 5-cm wide tendon inserts into the upper humerus.
Pectoralis minor muscle: It arises from the third, fourth, and fifth ribs, near their cartilages, and from the aponeuroses over the intercostal muscles. It inserts into the coracoid process of the scapula.
Lateral Chest Wall: Serratus anterior muscle
Serratus anterior muscle: It originates from the lateral part of the first eight to nine ribs and inserts into the medial aspect of the scapula.
Posterior Chest Wall: Latissimus Dorsi
Latissimus Dorsi muscle: It originates from the spinal processes of the lower thoracic spine and the posterior iliac crest and inserts into the upper portion of the humerus.
Figure 14.2 The latissimus dorsi muscle is the main muscle encountered and divided during a posterolateral thoracotomy.
General Principles
In order to preserve chest wall function, muscle-sparing techniques should be utilized whenever possible. Excessive rib retraction should be avoided to prevent rib fractures, and all ribs should be preserved when possible.
The thoracic wall structures should be closed by reapproximating the divided muscles in multiple layers.
Avoid over-approximating the ribs in order to reduce postoperative pain.
Preoperative placement of a double-lumen endotracheal tube or a bronchial blocker allows isolation of the ipsilateral lung and facilitates the exposure of posterior mediastinal structures, such as the descending thoracic aorta and the esophagus.
Positioning
In hemodynamically unstable patients, often there is no time for special positioning and the patient is placed in the standard supine position.
Posterolateral Thoracotomy
The patient is placed in a lateral decubitus position with the hips secured to the table by wide adhesive tape. Bean bags should be used to provide additional support.
The lower leg is flexed at the knee, while the upper leg is straight and a pillow is placed between the knees.
A rolled sheet is placed under the axilla to support the shoulder and upper thorax.
The arm on the side of the thoracotomy is extended forward and upward (praying position) and placed in a padded-grooved arm holder in line with the head.
Overextension can lead to brachial nerve injury.
The lower arm is extended and placed on a board at a 90° angle.
Figure 14.3 Positioning of a patient for a posterolateral thoracotomy taking care to protect and pad both arms and the decubitus axilla.
Incision(s)
The selection of incision should be based on the clinical condition of the patient, the location of the operation (emergency room versus operating room), the need for thoracic aortic cross-clamping, the location of any penetrating injuries, and the suspected injured organs. Incisions such as a posterolateral thoracotomy requiring special time-consuming positioning of the patient should be avoided in the unstable patient.
Median Sternotomy
It is the incision of choice in penetrating injuries to the anterior chest with suspected cardiac or upper mediastinum great vessel injury.
It provides good exposure of the heart, the anterior mediastinal vessels, both of the lungs, the middle to distal trachea, and left main stem bronchus. It is quick to perform, bloodless, and causes less postoperative pain and fewer respiratory complications than a thoracotomy.
It does not provide good exposure of the posterior mediastinal structures and does not allow adequate access for cross-clamping of the thoracic aorta for resuscitation purposes.
The incision is made over the center of the sternum, extending from the suprasternal notch to the xiphoid and is carried down to the sternum.
The sternum is scored in the midline with electrocautery to direct the saw or the Lebsche knife, which is then used to divide the sternum.
The interclavicular ligament at the suprasternal notch is cleared from its attachment to the sternum using a combination of cautery and blunt dissection, always staying close to the bone to avoid injuring the underlying vessels.
Confirm clearance of the posterior wall of the suprasternal notch by passing the index finger behind the manubrium.
Note that the pneumatic saw does not work in the presence of soft tissues!
Place the hook of the pneumatic saw or the Lebsche knife under the suprasternal notch and lift the sternum upwards.
Ask anesthesia to hold ventilation and divide the sternum directly in the midline, maintaining upwards traction along the entire length.
Place the Finochietto retractor in the upper part of the sternotomy and spread the sternum.
