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The most common indication for carinal resection is a neoplasm (benign or malignant) involving the carina. The neoplasm may be primarily tracheal, arise from the carina itself, or extend from the lung to involve the carina. All patients must be rigorously screened for metastatic disease and medical contraindications to such extensive surgery. A careful evaluation of pulmonary function, if lung resection is to be included, is mandatory and should include spirometry and quantitative ventilation perfusion scans. Bronchoscopic evaluation of the extent of disease is imperative. For a right carinal pneumonectomy (the most common carinal resection) the distance from the right distal tracheal margin to the proximal medial left mainstem should not exceed 4 cm in most cases. Resections that exceed this are likely to result in excessive anastomotic tension. Guidelines for other resections are less well established and must be individualized. All patients should be weaned from steroids and not require mechanical ventilation. Prior irradiation is a relative contraindication and should be accompanied by omental wrapping when carinal resection is considered.
There are a variety of reconstructive possibilities following carinal resection (Figure 1). Choosing among them depends on the patient’s specific anatomy and pathology.
Mediastinoscopy is valuable in mobilizing the pretracheal space, dissecting the left paratracheal-tracheobronchial angle to lessen the risk of injury to the left recurrent nerve, and to sample potentially involved mediastinal nodes. Mediastinoscopy is ideally performed at the time of planned resection to avoid scarring and limitation of mobility.
The surgical approach for most carinal resections is a right posterolateral thoracotomy. Median sternotomy for very limited carinal resection and extended clamshell incision for left carinal pneumonectomy are occasionally useful.
Anesthesia is best conducted with an extra long endotracheal tube that can be advanced into the left mainstem bronchus during initial dissection. During the resection and anastomosis, ventilation of the left lung across the operative field with a separate sterile endotracheal tube allows deflation of the right lung and easy placement of anastomotic sutures.
The initial dissection is commenced by division of the azygous vein to expose the carina. The distal trachea, right and left mainstem bronchus are encircled. Care must be exercised when encircling the distal trachea to avoid injury to the left recurrent nerve. Lateral dissection along the airway is limited to preserve blood supply. An initial conservative incision into the distal trachea is guided by flexible bronchoscopy through the oral endotracheal tube. Subsequent incisions are similarly performed. It is best to be conservative at first to allow for the assessment of feasibility of reconstruction. For neoplasms, frozen section evaluation is imperative. One must strike a balance between the desire for clean margins and the ability to reconstruct the airway.
The technique for reconstructing the airway is the same regardless of the level. Traction sutures (2-0 Vicryl) are placed in the midlateral position of the proximal and distal airway to be reconstructed. These are best placed circumferentially around a cartilaginous ring at least one ring removed from the transected end of the airway. These sutures should never be placed in the membranous wall of the airway. These sutures are used to assess the ability of the airway to be approximated and are tied together before tying individual anastomotic sutures to lessen tension on the airway (Figure 2).
If excess anastomotic tension is thought to exist, release maneuvers may help reduce tension on the anastomosis. Division of the pulmonary ligament and hilar release accomplished by dividing the pericardium circumferentially around the hilum provide an additional centimeter or two of mobility to the distal airway. Suprahyoid release maneuvers do not add much additional length for carinal resection procedures.
Once it has been determined the airway can be reapproximated, individual anastomotic sutures (4-0 Vicryl) are placed circumferentially (Figure 3). Using this open technique, careful precise placement of sutures is easily achieved. The sutures are placed about 3 to 4 mm. apart and the same distance from the transected end. If there is a size discrepancy, no attempt should be made to "tailor" the ends by crimping or wedging. Careful spacing of the sutures will help to overcome any size discrepancy. This will by necessity, however, lead to telescoping of the anastomosis. I am unaware of this causing any problems in our experience. Wedging or crimping of either end could predispose the anastomosis to the development of a fistula.
When using the interrupted open technique, it is mandatory to develop a system to arrange the sutures to avoid confusion when the time comes to tie these sutures. By convention, I have always placed the first anastomotic suture at "6 o'clock" when viewing the anastomosis from the operative field (Figure 2). All sutures are placed to allow the knots to be on the outside of the anastomosis. The first suture is clipped to the cephalad portion of the surgical drapes on the side of airway they are being placed. Each subsequent suture is placed "inside" the previous suture and clipped to the drapes caudally to the previous suture. This process is continued until the lateral traction sutures are reached (6 o'clock to 9 o'clock). The same process is repeated on the opposite side (6 o'clock to 3 o'clock). The final sutures are placed from 9 o'clock to 3 o'clock and clipped to the drapes inferiorly. The sutures are tied in reverse order of placement. The placement of the back wall sutures is especially critical. By placing the sutures "inside" the previous suture and then tying in reverse order of placement, one avoids entangling the sutures as they are being tied.
Prior to tying the anastomotic sutures, the table is taken out of flexion, crossfield ventilation is terminated, and the oral endotracheal tube is advanced onto the left mainstem bronchus. Sometimes advancing the oral tube distracts the left mainstem bronchus making approximation with the traction sutures difficult. When this situation arises, it is best to pull the oral tube back into the trachea and temporarily reestablish ventilation crossfield. Options to ventilate the patient in this circumstance include high frequency ventilation, intermittently inserting a small cuffed pediatric endotracheal tube into the left mainstem as the individual sutures are tied, or tying the individual sutures temporarily occluding the anastomosis and accepting some degree of leak.
When concern exists about the "gap" between the 2 ends of the airway to be approximated, it is helpful to have the assistant cross the next suture to be tied. This allows the anastomotic suture to be tied with as little tension as possible.
The front row of sutures is easily tied under direct vision. This part of the anastomosis is where the largest gap exists. It also corresponds to the membranous wall and therefore has the greatest mobility making approximation easier.
Once the front row of sutures is tied, the back row sutures should be tied. This is best accomplished by gently retracting the traction sutures to allow the surgeon to get a finger behind the anastomosis to "square the knot down". Because the last sutures are tied by feel, we have preferred 4-0 Vicryl to any other suture. It slides easily, doesn't stretch, and holds a knot securely.
When all of the sutures have been tied, the anastomosis should be checked to see if it is airtight. The anesthesiologist deflates the cuff of the endotracheal tube and ventilates the patient. An airleak around the endotracheal tube should be appreciated. With the cuff deflated, the anesthesiologist ventilates the patient to 20, 30, and 40 cm. of pressure. These pressures are achieved by manually occluding the nose and mouth. The operative field is submersed in saline to allow identification of any leaks. Any leaks should be repaired even to the point of taking the entire anastomosis apart and starting all over if the leak can't be repaired.
Once the anastomosis has been secured, soft tissue coverage of the anastomosis is achieved by a pedicled flap of pericardial fat, pleura, or intercostal muscle. If intercostal muscle is to be used, the periosteum should be stripped to avoid bone formation and subsequent stenosis of the anastomosis.
There are many variations involving end-to-side reimplantation of the airway (Figure 1). These are very demanding anastomoses. Tension on the anastomosis must be avoided at all costs. Mobilization of the airway must also avoid devascularization. The opening in the airway for the anastomosis should entirely be in the cartilage to give maximum support and help avoid tearing (Figure 4). The opening should be at least 2 cm from the other anastomotic suture line. The size of the opening should be comparable to the end of the bronchus to be reimplanted. The technique of suturing, traction sutures and tying the anastomotic sutures is exactly as previously described.
Postoperative care is demanding. Bedside bronchoscopies should be performed as needed to help clear secretions. Careful inspection of the anastomosis for impending problems should be done with each bronchoscopy. The most ominous non-anastomotic postoperative problem is ARDS. This has been the leading cause of early mortality in our experience. It usually occurs 48 to 72 hours after surgery and is very insidious in onset. A fine interstitial pattern on chest x-ray associated with tachypnea and desaturation are early signs of this dreaded problem. Aggressive measures are required. Intubation, diuresis, broad-spectrum antibiotics and bronchoscopy should be done immediately. We have had some encouraging experience utilizing inhaled nitric oxide in these circumstances and should be employed if available.
- Bronchoscope for intraoperative use
- Extra long endotracheal tube for initial intubation
- Sterile endotracheal tube for cross-field ventilation
- Jet ventilator on stand-by
Tips & Pitfalls
- Thorough preoperative bronchoscopy is necessary to select appropriate candidates for resection.
- Stage cancer patients thoroughly to ensure there is no regionally advanced or metastatic disease.
- Perform mediastinoscopy under the same anesthetic as the resection to permit staging, evaluate resectability, and permit dissection of the distal trachea.
- Use intraoperative bronchoscopy to guide airway incisions.
- Make judicious use of intraoperative frozen section evaluation to assess margins.
- Use release maneuvers to avoid anastomotic tension.
- Make sure the anastomosis is free of air leaks before completing the operation.
- Wrap the anastomosis with vascularized tissue.
Results have been gratifying in recent years. The operative mortality rate has decreased to less than 10%. Long-term survival in highly selected patients with non-small cell lung cancer has approached 45%.
- Mathisen DJ, Grillo HC. Carinal resection for bronchogenic carcinoma. J Thorac Cardiovasc Surg 1991;102:16-23.
- Mitchell JC, Mathisen DJ, Wright CD, Wain JC, Donahue DM, Moncure AC, Grillo HC. Clinical experience with carinal resection. J Thorac Cardiovasc Surg 1999;117:39-53.
- Mitchell JD, Mathisen DJ, Wright CD, Wain JC, Donahue DM, Allan JS, Moncure AC, Grillo HC. Resection for bronchogenic carcinoma involving the carina: long-term results and effect of nodal status on outcome. J Thorac Cardiovasc Surg 2001;121:465-71.