Tracheal Resection

Introduction

Tracheal resection may be undertaken for tracheal strictures and tracheal tumors. Most commonly the trachea is exposed through a cervical incision, but for distal tracheal or carinal access either a sternotomy or a right thoracotomy may be required. Up to half the trachea may be resected with construction of a primary tracheal anastomosis. For the extensive resections, release techniques will be required. Preoperative planning is important to precisely define the tracheal lesion and always includes imaging and bronchoscopy.

Key Operative Points

1.

Preoperatively one must accurately assess the length and location of the lesion that is being resected.
2.

The tracheal resection must include all of the diseased airway so that the anastomosis can be done with healthy trachea.
3.

Neck flexion and release procedures should be done as required in order to minimize tension on the anastomosis.
4.

Circumferential mobilization of the airway should be minimized to maintain the circulation of the trachea.
5.

The recurrent laryngeal nerves are located in the trachea-esophageal groove and should be preserved to prevent vocal cord palsy.

Perioperative Period

History

1.

History of diabetes, previous external beam radiation, or steroid use, which can impair the healing of the trachea
2.

Previous tracheostomy or oral tracheal intubation and, if so, the duration of intubation
3.

History of Wegener disease or sarcoidosis, which can lead to tracheal stenosis
4.

A history of cigarette smoking
5.

Dyspnea and, if so, the duration and severity
6.

Cough

Physical Examination

1.

Overall body habitus
2.

Examination of the neck, including length, ability to extend the neck, and presence of kyphosis
3.

Cervical lymph adenopathy
4.

Audible stridor or wheezing

Imaging

Imaging is important to fully define the nature of the tracheal lesion for preoperative planning of the operation, with regard to location of the incision and the need for any tracheal release procedures.

1.

Chest and neck radiograph may show evidence of airway obstruction in the proximal trachea and would also detect gross mediastinal adenopathy or lesions in the lungs.
2.

Computed tomography (CT) scan is the most informative imaging study.
- a.
  
  It provides information regarding both the intraluminal and extraluminal extent of tracheal lesions.
- b.
  
  Evaluation of spread of tracheal cancers to the regional lymph nodes or the pulmonary parenchyma
- c.
  
  Allow for assessment of any other underlying pathology in the lung parenchyma.

Indications

1.

Airway intubation injury is the most common cause of tracheal strictures. It can occur from placement of oral endotracheal tubes or from previous tracheostomy. Most intubation injuries are relatively proximal and short and best managed with tracheal resection.
- a.
  
  Strictures that occur after tracheostomy may be located either at the site of the tracheal stoma or at the site of the cuff on the tracheostomy tube.
- b.
  
  Stenosis resulting from oral tracheal intubation usually follows a period of prolonged intubation for ventilator support. The level of injury can be the glottis, the subglottic segment, or the trachea.
2.

Idiopathic tracheal stenosis is a circumferential fibrotic lesion that involves the subglottic area as well as the proximal trachea.
3.

Tracheal tumors may be benign or malignant. In children, the majority of tumors are benign, whereas in adults, most are malignant.
- a.
  
  The most common benign tumors are carcinoid tumors and chondromas.
- b.
  
  The most common malignant tumors are squamous cell carcinoma and adenoid cystic carcinoma. Many malignant tracheal tumors are either locally advanced at presentation or have metastasized and as such are not treated with tracheal resection.

Contraindications

1.

The maximum length of trachea that can be resected with a primary anastomosis is 5 to 6 cm or roughly half the length of the trachea. Unless the surgeon is planning on a prosthetic tracheal replacement, longer lesions are not amenable to tracheal resection.
2.

Tracheal resection is generally not indicated in patients whose tracheal tumors have metastasized, although occasionally adenoid cystic metastases can progress extremely slowly and resection of an obstructing primary tracheal tumor may be appropriate.
3.

Patients need to be physiologically fit for surgery, although most patients can tolerate a transcervical operation well.
4.

Relative contraindications include:
- a.
  
  Diabetes
- b.
  
  Previous high-dose radiation to the trachea
- c.
  
  Current high-dose steroid use
- d.
  
  Active ongoing inflammation in the tracheal stricture

Preoperative Preparation

1.

An acutely inflamed tracheal stricture should not be operated on; the surgeon should wait until the inflammatory phase has resolved with treatment and the stricture has matured.
2.

Wean off of high-dose steroids prior to surgery.
3.

Pulmonary function tests can give an objective measure of the degree of airflow obstruction. Flow volume loops will demonstrate the degree of airflow obstruction during both the inspiratory and expiratory phase of respiration. Typically intrathoracic lesions cause obstruction of airflow during expiration, whereas lesions that are more proximal (or extrathoracic) will cause airflow obstruction during inspiration. With severe advanced, both inspiratory and expiratory airflow obstruction may be present.
4.

Bronchoscopy is used to accurately characterize the tracheal lesion prior to resection. That includes biopsy for histologic diagnosis of tracheal tumors. It also allows the surgeon to measure the longitudinal extent of tracheal lesions, document their precise location relative to the vocal cords and the carina, and evaluate the degree of obstruction of the airway. All of these factors are very important in establishing a patient treatment plan. In patients with severe airway obstruction and respiratory distress, endobronchial therapy via the bronchoscope can be used to relieve the obstruction and stabilize the patient until such time as definitive resection can be undertaken. That could include laser débridement or mechanical débridement of an endobronchial tumor or dilation of a benign stricture. Bronchoscopy is also useful to document vocal cord function prior to surgery.

Operative Period

Anesthesia

Anesthetic management for tracheal resection is complex and requires close cooperation and communication between the surgeon and the anesthesiologist. The surgeon should always be present at the time of induction of anesthesia.

A rigid bronchoscope may be required to initially secure the airway, and dilation of a narrowed trachea may be required in order for an oral endotracheal tube to be passed at the beginning of the procedure.

Once the trachea has been exposed and the lesion identified, the trachea is divided distal to the lesion, and the distal trachea thus exposed is intubated with a cuffed endotracheal tube, which is then connected to a sterile ventilatory circuit that has been passed onto the operative field.

Performance of the tracheal anastomosis may require intermittent interruption of ventilation with removal of the endotracheal tube. Alternatively, jet ventilation may be used, which does not require a closed circuit and will not interrupt the conduct of the anastomosis in order to remove and replace the endotracheal tube.

Ideally at the end of the procedure the patient will no longer require positive pressure ventilation and be breathing spontaneously so that they can be extubated in the operating room.

Positioning

The patient is placed in the supine position. An inflatable bag is placed under the upper back, which is inflated to provide extension of the neck and then deflated during the operation to facilitate neck flexion for the conduct of the anastomosis.

For carinal resections, where one chooses to approach the operation transthoracically, the patient will be positioned in the left lateral position for a right fourth interspace thoracotomy.

Perioperative Antibiotics

One or two grams of Ancef are given intravenously preoperatively, and two doses are given postoperatively. Alternatively, 600 mg of clindamycin can be substituted in the patient who is allergic to penicillin.

Monitoring

1.

Continuous electrocardiogram
2.

Oxygen saturation monitor
3.

Bispectral index (BIS) monitor for depth of anesthesia
4.

Intraoperative monitoring of the recurrent laryngeal nerve
5.

Blood pressure monitoring with an arm cuff should be adequate (unless the patient requires a thoracotomy).

Instruments and Equipment to Have Available

1.

Rigid bronchoscopes of various sizes
2.

Gum-tipped tracheal dilators for rigid bronchoscope
3.

High Frequency (JET) ventilator and catheters for High Frequency (JET) ventilation
4.

Nerve conduction monitoring apparatus and special endotracheal tube for nerve conduction monitoring of the recurrent laryngeal nerves
5.

Sterile ventilatory circuit for cross table ventilation of distal trachea in the operative field
6.

Several sizes of endotracheal tubes on the sterile field
7.

Bipolar cautery
8.

Inflatable bag for positioning behind the patient’s back to facilitate neck extension and flexion during the procedure

Key Anatomic Landmarks

1.

Cricoid cartilage
2.

Anatomic location of the recurrent laryngeal nerves ( Fig. 22.1 )

Fig. 22.1

Segmental arterial blood supply of trachea coming in laterally. Course of recurrent laryngeal nerves in tracheoesophageal groove.

Prerequisite skills

1.

One must be facile with rigid (and flexible) bronchoscopy and oral tracheal intubation.
2.

Familiarity with the setup and function of the High Frequency (JET) ventilator

Operative Risks

1.

Failure to secure the airway at the time of anesthetic induction in a patient with significant tracheal obstruction due to tumor or stricture
2.

Failure to accurately localize the upper and lower extent of the tracheal lesion on external examination of the trachea at the time of tracheal resection
3.

Damaging one or both recurrent laryngeal nerves with attendant vocal cord palsy
4.

Failure to protect the innominate artery from a tracheal anastomosis
5.

Producing a tracheal anastomosis that is under tension by not using tracheal mobilization procedures or by resecting too much trachea
6.

Excessive circumferential mobilization of the trachea, resulting in devascularization of the trachea and ischemic breakdown of the anastomosis ( Fig. 22.1 )
7.

Damage to the esophagus during dissection of the posterior tracheal wall
8.

Inadequate ventilation of the patient during the conduct of the procedure, with secondary hypoxemia and/or hypercarbia

Surgical Procedure