Posterolateral thoracotomy is the standard workhorse for most thoracic surgeons. It offers excellent direct visualization of the entire thoracic cavity, including the posterior diaphragmatic sulcus and apex of the hemithorax. The incision generally is centered over the fifth intercostal space, which corresponds to the greater fissure of the lung. This provides an unobstructed view of the base of the fissure, the pulmonary artery, and the hilum. The incision generally is used for anatomic lung resections, including pneumonectomy and lobectomy. It offers the easiest access for radical lymphadenectomy. An extended posterolateral thoracotomy is used for Pancoast resection, extrapleural pneumonectomy, and aortic transection.
The patient is placed in a standard lateral decubitus position, with the ipsilateral arm extended forward. The inferior tip of the scapula is palpated and generally marked. The incision begins approximately 3 cm posterior to the scapula tip and approximately halfway between the scapula and the spinous process. The incision curves around the tip to lie along the top margin of the sixth rib (fifth intercostal space). In general, it extends to the anterior axillary line (Fig. 2-1). The soft tissue and Scarpa's fascia are divided. The latissimus dorsi muscle is divided. The auscultatory triangle, the space bounded by the lower border of the trapezius, the serratus anterior, and the medial margin of the scapula can be identified at this time. The serratus anterior muscle can be spared by freeing it from the soft tissue of the auscultatory triangle and the muscle rotated forward. Preservation of the serratus anterior muscle helps to preserve the motion of the shoulder girdle and quickens recovery time. An intact serratus anterior muscle can limit the spread of the fifth and sixth ribs. This can be overcome by detaching the lower slips of attachment of the muscle from the eighth, seventh, and sixth ribs (Fig. 2-2).
Standard posterolateral thoracotomy incision, with extrathoracic musculature and surface landmarks. The incision wraps around the tip of the scapula and parallels the course of the sixth rib.
Posterolateral thoracotomy divides the latissimus dorsi muscle and rotates the serratus anterior muscle forward. The incision appears centered on the greater fissure of the lung, providing access to the pulmonary artery at the base of the fissure.
If the ribs are to be preserved, the attachment of the intercostal muscles is divided from the top of the sixth rib. It is important to stay on the top surface of the lower rib to avoid injury to the neurovascular bundle of the upper rib. This is best done by proceeding from posterior to anterior along the line of the external intercostal fibers. For maximal spread of the ribs, it is important to take down these attachments as far forward as the costochondral junction and as far posterior as the transverse processes of the vertebral body. Both these landmarks can be palpated by a finger passed just superficial to the intercostal muscle layer. In general, there is no need to disrupt the erector spinae ligament, which passes perpendicular to the posterior rib behind the posterior axillary line.
Either removing the rib or “shingling” the posterior rib can achieve additional spread of the ribcage. To remove the rib, the periosteum is raised initially by cautery, and then the plane between the cortical bone and the periosteum is dissected with a periosteal elevator. The neurovascular bundle is pushed out of the inferior groove of the rib with the elevator. The elevator is passed from posterior to anterior above the rib and from anterior to posterior below the rib to take advantage of the angle of the superficial intercostal muscle fibers as they insert into the bone. The direction of these fibers can be remembered simply by thinking of the angle of your arm when you place your hand in your pocket. After the periosteum is raised, the rib is cut, usually with a guillotine rib cutter. This device cuts the bone to one side and thus needs to be turned to remove the entire stripped portion of bone.
“Shingling” a rib involves removal of approximately a centimeter length of rib just anterior to the erector spinae ligament to allow further distraction of the fifth and sixth ribs without a subsequent midshaft fracture of the rib (Fig. 2-3). These small bony defects are much less painful than midshaft fractures. It is important to free the intercostal neurovascular bundle from beneath the inferior groove of the posterior segment of the remaining rib to prevent neuropraxia of the nerve. Increasing the distraction of the ribs can stretch the nerve if it remains fixed to the undersurface of the posterior fragment. Freeing this nerve provides additional visualization of the thorax without nerve injury. Closure begins with placement and securing of chest tubes. Paracostal sutures then reapproximate the spread ribs. If no rib has been taken, generally four sutures suffice. If a rib has been removed, six to eight sutures are commonly required to prevent a chest wall hernia. If a midshaft rib fracture has occurred, the paracostal sutures should be placed to prevent movement of the fracture. Fracture ends sometimes are best treated by removing the jagged portion of the rib with a rib cutter, with the end result similar to a “shingle.” The ribs should be approximated but not brought tightly in apposition to each other because this frequently causes the bones to fuse subsequently, which can limit surgical choices for redo thoracotomies. The serratus anterior muscle is reapproximated to the soft tissue overlying the auscultatory triangle, and then the latissimus dorsi muscle is sewn back together. Approximation of the latissimus dorsi fascia with minimal bulky muscle will minimize pain and provide a superior cosmetic result. Two additional layers of closure reapproximate Scarpa's fascia and the skin.
Technique to “shingle” the rib to increase exposure of a posterolateral thoracotomy. (A) The initial periosteal cut is made with a bovie and elevated. (B) Subperiosteal dissection protects the neurovascular bundle. (C) The osseous rib fragment is removed. (D) The nerve is susceptible to stretch injury unless freed from the undersurface of the rib.
The posterolateral thoracotomy incision provides the best unobstructed view of the entire hemithorax (Fig. 2-4).
Anterior and posterior views of the hilum of the lung from a standard posterolateral thoracotomy. A. Anterior view of right lung. B. Posterior view of right lung. C. Anterior view of left lung. D. Posterior view of left lung.
A generally long incision, the posterolateral thoracotomy is associated with more tissue injury to the extrathoracic musculature and soft tissue. It is also associated with a longer recovery time than almost any other incision (with the exception of the clamshell incision, which is generally slightly more morbid). It takes more time to open and close this incision compared with minimally invasive incisions. Epidural catheters have improved acute postoperative pain control and are especially helpful in the face of impaired lung function.
Key bony landmarks (Fig. 2-1) include the tip of the scapula,1 the sixth rib (identified as the first rib contributing to the costal margin), the fifth rib (identified as the last rib inserting directly on the sternum), the erector spinae ligament, the costochondral junction, and the transverse process of the sixth vertebral body. Soft tissue landmarks include the latissimus dorsi muscle (innervated by the thoracodorsal nerve) and the serratus anterior muscle originating from the eighth to second ribs and innervated by the long thoracic nerve. A small vascular perforator enters each of the slips of the serratus anterior muscle where they insert on the rib. Both the thoracodorsal nerve and the long thoracic nerve can be injured. Ribs can be fractured if the distraction exceeds the ability of the rib to displace owing to muscle attachments.
Tip of the scapula, the xiphoid tip, the costal margin, the sixth rib insertion onto costal margin, the fifth rib insertion into the sternum, the anterior border of the latissimus dorsi muscle, and the posterior border of the pectoralis major muscle.