TSRA Content:
Author: Jacob Klapper, MD
Positioning and Preparation
The key to performing a successful thoracotomy begins with the positioning of the patient -- KEY: Ensure that the correct side is up.
While the patient is still supine, s/he is positioned with the hips just below the "break" in the bed, so that when s/he is placed in lateral decubitus and the bed is flexed the interspaces between the ribs will widen to a maximal degree. Proper cushioning of the patient during the procedure is critical to avoid iatrogenic injuries. To avoid damaging the brachial plexus, some institutions place an axillary roll; at our institution, we ensure that a closed fist can be passed through the space underneath the axilla comfortably when the patient is in the decubitus position.
Next, secure the arms with pillows in between them to protect the ulnar nerve. The legs should be positioned with the top leg straight and the bottom leg bent to minimize pressure between the knees. Pillows are placed between the legs at all points to avoid pressure injury. With the arms, hips, and legs positioned appropriately, the bed is flexed and the beanbag, if being used, is molded into position. The patient is then placed in reverse Trendelenburg position to raise the surgical field to a comfortable height for the surgeon. The patient is secured with strong tape at both the hip and the shin levels.
Opening
Preparing for the incision begins with palpating and marking the tip of the scapula, which can be challenging in heavier patients. To do so, place one hand on the shoulder and press towards the patient’s feet firmly so that the tip of the scapula can be felt against the other hand, which is held flat again the posterior chest wall below the scapula. Other important landmarks include the position of the nipple in men, as well as the spine. In thinner patients it may even be possible to count the ribs starting inferiorly and working cephalad.
Mark the thoracotomy just distal to this scapular tip to follow the curve of the ribs. The surgeon generally stands on the posterior side of the patient and the assistant stands on the anterior side. After the skin incision is made, the first muscle encountered is the latissimus dorsi. This muscle can be slowly divided using Bovie cautery so that bleeding at the muscle edges is kept to a minimum. The next muscle encountered is the serratus anterior, which can commonly be spared. In children it is imperative to try and spare the serratus anterior to avoid development of post thoracotomy scoliosis. To do so, retract the muscle and divide its attachments to the chest wall.
Once the serratus has been mobilized and the chest wall is reached, a scapular retractor is placed under the scapula by the assistant, and the surgeon can slip a hand beneath the scapula and towards the apex to count the ribs. The most helpful landmark to remember is the second intercostal space which is the largest of the interspaces. The first rib is often not easily palpable.
For the typical lung procedure, the thoracotomy is made in the fourth or fifth intercostal space, which allows entry into the pleural space directly over the pulmonary hilum. The best incision for an esophageal procedure depends on the location where the majority of work will take place: 5th or 6th intercostal space for an esophagogastrectomy; slightly lower for procedures focusing near the diaphragm (ex. esophagomyotomy or Belsey fundoplication). Prior to entry into the chest, confirm with the anesthesiologist that the lung on the operative side has been deflated thereby minimalizing the potential for injury to the lung.
After selecting the appropriate interspace, divide the intercostal muscles off the superior aspect of the bottom rib, as the intercostal vessels run on the inferior border of the ribs. The thoracotomy itself will generally be longer than the skin incision; use retractors to help extend it both anteriorly and posteriorly underneath the skin/muscles of the chest wall. Taking care not to divide the erector spinae muscles posteriorly. A Tuffier or other comparable retractor is placed, opening it slowly to avoid fracturing a rib. The rib below the interspace can be "shingled" if it is anticipated that a more generous exposure will be needed. Namely, this rib can be divided posteriorly with a rib cutter to permit wider retraction, and then reapproximated later. For certain procedures, the rib may be removed nearly in its entirety with the periosteum intact to provide for additional exposure. This maneuver is usually necessary to start an extrapleural dissection (during mesothelioma surgery, for example). A Balfour retractor can then be placed perpendicularly in relation to the Tuffier. The Tuffier retractor provides maximal cranial-caudal distraction, while the Balfour retractor provides maximal medial-lateral distraction. Control any incisional bleeding from the muscle or periosteal edges and proceed with the intended operation.
Intercostal Flap
If an intercostal muscle flap is to be created, it should be done prior to entering the interspace. First, score the periosteum of the ribs above and below the intercostal muscle to be harvested, bisecting each rib lengthwise. Use a periosteal elevator to scrape the periosteum off the rib towards the muscle to be harvested. Slide the elevator underneath the rib and dissect away the intercostal muscle with the periosteum intact by sliding it along the rib in the direction of the muscle fibers both above and below the intercostal muscle to be harvested. Be especially careful when dissecting the inferior border of the upper rib to avoid injuring the neurovascular bundle. Dissect as medial and lateral as possible to maximize the length of the flap, which will need to reach the pulmonary hilum. Finally, the flap is transected medially, and positioned safely out of the way, often wrapped in a moist sponge. Taking care not to compress the flap, retractors can then be placed in the interspace to facilitate the thoracotomy.
Closing
After positioning the chest tube(s) but before having the anesthesiologist re-insufflate the lungs, place the pericostal sutures. There are a number of ways to close a thoracotomy, but ideally one can avoid compressing the infracostal neurovascular bundle and contributing to post-thoracotomy pain by either drilling holes in the inferior rib through which sutures may be passed or placing the sutures in between the neurovascular bundle and the rib. Normally two to three figure-of-eight heavy gauge absorbable or long-term absorbable sutures are all that is required. The lung is then reinflated under direct vision. The serratus fascia and the latissimus dorsi muscle are reapproximated, taking care to identify and approximate each layer individually. The dermis is closed, and the skin is either sutured or stapled depending on surgeon preference.
Serratus Flap
The serratus flap is typically used when a large space defect has developed in an infectious setting or when reinforcing a high-risk bronchial stump for which a lesser flap has not been sufficient. The arterial supply of the serratus anterior muscle consists of the lateral thoracic artery (arises directly from the axillary artery) and branches from the thoracodorsal artery (arises from the subscapular artery). The long thoracic nerve innervates the muscle; injury to this results in a winged scapula.
Separate the serratus anterior muscle from the underside of the latissimus dorsi. Taking care to preserve the neurovascular bundle, divide the slips of muscle to be harvested from those to be left in situ.
The majority of the 9 or 10 slips of serratus muscle may be harvested if a significant volume of tissue is needed; alternatively, only the lower 3-4 slips of muscle may be harvested if a winged scapula is judged to be an intolerable possibility. Next, divide the slips of serratus at both their origin (posteriorly, at the scapula) and insertion (anteriorly, at the ribs). The neurovascular bundle can be skeletonized to achieve greater length of the pedicle. Typically, a 6-8 cm section of the third rib is removed from underneath the scapula. The serratus flap is then lowered through the resultant gap into the chest to reinforce a bronchial stump or occupy an empty space.