Tracheal Reconstruction

Anatomy and Physiology

The trachea begins at the caudal aspect of the cricoid cartilage and extends to the carina. During organogenesis, the laryngotracheal structures form from the laryngotracheal bud, emanating from the foregut immediately caudal to the fourth branchial arch. The development of the tracheoesophageal septum ensues and is crucial in separating these structures. As mentioned, the newborn tracheal diameter ranges from 4 to 7 mm, and the adult diameter ranges from 12 to 25 mm. A newborn trachea is approximately 4 cm long and ranges from 11 to 13 cm in adults.

The trachea comprises stacked c-shaped cartilaginous rings, and this rigid structure is key to preventing collapse. The membranous posterior wall contains the trachealis muscle, and creating this incomplete ring structure allows the trachea to expand during the dynamic respiratory process. Typically, 16 to 20 cartilaginous rings along the trachea grow with the patient early in life.

When considering reconstruction, it is important to understand the blood supply to the trachea. Arterial supply is provided by branches from the inferior thyroid and bronchial arteries, which enter the lateral sidewall bilaterally. Preserving this lateral vascular supply during reconstruction is crucial.

Another key element in tracheal reconstructive surgery is a clear understanding of nearby structures and their intimate relationships with the airway. In the cervical region, the esophagus parallels the posterior wall of the trachea. The recurrent laryngeal nerves run in the tracheoesophageal groove bilaterally before entering the larynx and must be identified and preserved. The thyroid gland spans the cervical trachea and is intimately attached anteriorly via Berry ligament. In the thoracic cavity, the trachea is surrounded by multiple mediastinal structures, particularly the lungs and vascular structures entering and leaving the heart. This fact emphasizes the necessity of a multidisciplinary approach when managing distal or LSTS reconstructions, which is discussed later.[4][5]

Indications

In general, symptomatic patients meet indications for surgical reconstruction. When considering tracheal stenosis repair, knowing the Cotton-Myer grade and determining if it is an SSTS or LSTS are critical. These patients have 3 options for treatment: observation and conservative management, endoscopic surgical repair, and open surgical repair.[6] General indications include the following:

Conservative Observation

• Poor surgical candidate
• Ventilator dependent due to pulmonary disease
• Asymptomatic mild disease
• The pediatric patient is still growing

Endoscopic Repair

• Symptomatic mild to moderate disease
• Thin scar band or web
• A stenotic segment of fewer than 1 or 2 tracheal rings
• Adjunctive procedures following open repair

Open Repair

• SSTS and LSTS
• Failed endoscopic repair
• Complete tracheal rings
• Concomitant cardiopulmonary abnormalities requiring repair

Contraindications

There are many relative contraindications to consider. First and foremost, the patient's overall health and prognosis must be considered, as a perfectly reconstructed tracheal lumen may still require a tracheostomy tube and ventilatory support in certain circumstances. The goals of the patient, the family, and the surgical team must be aligned, and expectations must be communicated and understood.

Fitness to undergo surgery must be considered, and if questionable, could be a reason to continue observation over reconstruction. Laryngeal stenoses must be addressed before embarking on tracheal reconstruction or perhaps concomitantly in select patients. Severe pulmonary dysfunction must be ruled out, and airway inflammation from underlying pulmonology or gastroenterology conditions must be addressed preoperatively to ensure a favorable environment for healing. Conditions resulting in poor wound healing, such as active infection, diabetes, previous irradiation, steroid use, or underlying inflammatory conditions, may also preclude surgical intervention.[7]

Equipment

The following equipment is required:

• Laryngoscopy/bronchoscopy set
• Suspension laryngoscopy set
• Microlaryngeal instrument set
• Endoscopes and tower
• Airway LASER (typically CO₂)
• Endoscopic airway balloons (size should be 2 mm larger than age-appropriate endotracheal tube)
• Head and neck soft tissue set
• Tracheotomy set

Personnel

These patients (pediatric patients in particular) frequently have multiple comorbidities, and it is important to have a full multi-disciplinary team in place both pre-and post-operatively. This team involves specialists in otolaryngology, cardiothoracic (CT) surgery, pulmonology, gastroenterology, critical care, anesthesiology, speech and language pathology, and care coordination. In particular, these patients should be managed through a multidisciplinary aerodigestive clinic in the pediatric population. This allows for collaboration and care coordination amongst physicians and other medical personnel, thus expediting care and minimizing risks and complications.[8]

Preparation

Before any airway reconstruction, the nature and severity of the stenosis are confirmed with a formal airway evaluation, including direct laryngoscopy and bronchoscopy by the Otolaryngologist. This is typically performed in conjunction with gastroenterology and pulmonology, with esophagogastroduodenoscopy and flexible bronchoscopy/bronchoalveolar lavage, as indicated, to ensure the health of the shared aerodigestive tract. 

If reconstruction is considered following formal airway evaluation and the patient’s clinical condition allows it, imaging is usually performed to help plan the surgical procedure and confirm findings. A high-resolution CT (HRCT) scan with contrast of the neck and chest helps define the stenotic segment and any cardiopulmonary abnormalities that need to be addressed. CT angiogram and MRI are sometimes helpful, depending on the nature and etiology of the pathology.

With recent advances in 3-D printing and rapid prototyping, many institutions are also beginning to utilize this technology in preoperative planning and intraoperative repair. Patient-specific 3-D models can be designed and printed quickly and cost-effectively from HRCT scans. In theory, this allows surgical teams to define the stenosis better, manipulate it preoperatively to test concepts and techniques and improve confidence intraoperatively. There are also reports of patient-specific bioresorbable implants being utilized to address difficult tracheobronchial stenoses with good preliminary data.[9] Ultimately, many believe that 3-D printing allows for patient-specific bioprinted grafts.[10]

Technique or Treatment

As outlined above, preoperative assessment and stenosis classification are key to selecting the appropriate repair technique. Lesions amenable to endoscopic repair and those requiring open repair confined to the extrathoracic trachea are often amenable to repair by a trained Otolaryngologist alone. When lesions become intrathoracic or concomitant cardiopulmonary abnormalities need repair, a transthoracic approach with sternotomy is often required. This requires enlisting CT surgery, and these procedures are often done using ECMO or CPB. The general steps are outlined below.

Endoscopic Repair [11]

• Clear communication between the surgeon and the anesthesiologist is paramount. During endoscopic balloon inflation, desaturation events likely occur, for which one must be prepared. Also, electrocautery or laser manipulation greatly increases airway fire risk, and all precautions must be followed.
• Preoperative IV steroids are encouraged, but prophylactic antibiotics are generally not required. Topical anesthesia using 4% lidocaine allows for improved anesthesia throughout the case and is generally recommended.
• Suspension laryngoscopy is performed, and adequate exposure is confirmed. 4 mm endoscopes are typically adequate for most patients but may be adjusted for small children.
• Identify the stenosis and determine whether radial incisions are appropriate before balloon dilation.
• Use cold steel instruments or an appropriate laser to make radial incisions through the stenosis if indicated.
• Insert an appropriately sized airway balloon into the airway, ensuring half of the balloon is distal, and half is proximal to the stenosis.
• Communicate with anesthesiologists, and once the patient is stable, inflate the balloon for the predetermined time.
• Deflate and inspect the stenosis and repeat dilation if indicated.
• Topical steroids can be administered with pledges or injections on the site of dilation to prevent restenosis.
• Hemostasis is achieved with topical agents (oxymetazoline, epinephrine)

Tracheal Resection and Reanastomosis [12]

• This is performed for SSTS and can often be done under general anesthesia with endotracheal tube intubation. If the lesion is distal or other cardiac repairs are being performed, ECMO or CPB are recommended.
• Preoperative IV steroids and antibiotics are encouraged.
• Exposure of the stenotic segment of the trachea is performed, ensuring the preservation of vital surrounding structures.
  • Extrathoracic lesions can be managed via a transcervical incision and approach.
  • Intrathoracic lesions often require a sternotomy.
• After exposure and identifying the stenotic segment to be resected, endoscopic visualization of the planned resection site is confirmed.
• Prolene sutures are secured below the stenosis to ensure distal control of the airway following resection.
• A vertical tracheotomy along the stenosis is performed, and visual inspection allows for confirmation of resection feasibility.
• Resection of the stenosis proceeds, using caution to avoid injury to surrounding structures.
• After resection, releasing techniques are performed to achieve a tension-free closure. These include anterior and posterior blunt dissection (avoiding disruption of laterally based vascular supply) and supra- and infra-hyoid-releasing maneuvers.
• The distal and proximal stumps are then reanastomosed in an interrupted fashion, beginning posteriorly and finishing anteriorly.
• The wound is closed. Depending on patient cooperation and the tension of the closure, the patient may remain intubated and sedated during the immediate postoperative process to ensure adequate healing.

 Slide Tracheoplasty [6]

• This procedure has become the standard of care for LSTS and distal lesions. It expands the stenotic segment while allowing for maximal tracheal preservation. Due to the nature and location of lesions managed with slide tracheoplasty, these are frequently performed via a sternotomy for adequate exposure. This also means that these patients generally require ECMO or CPB for the duration of the procedure.
• It is important to mention the clinical implications of a tracheal bronchus (bronchus suis). This is a rare (<1%) developmental abnormality identified by a bronchus coming off the trachea above the carina and often supplying the entire right upper lobe (1). This abnormality tethers the trachea and inhibits the surgeon’s ability to slide the cut tracheal ends into apposition, usually preventing a successful slide tracheoplasty.
• Preoperative IV steroids and antibiotics are encouraged.
• Exposure is more complicated, often requiring sternotomy, which is performed in conjunction with CT surgery.
• The stenosis site is confirmed endoscopically following adequate stenosis (often via sternotomy).
• The center of the stenotic segment is incised horizontally, and supra- and infra-hyoid-releasing maneuvers are performed.
• After adequate release, the posterior wall of the proximal segment and the anterior wall of the distal segment are incised vertically along the length of the stenosis.
• The 2 segments are overlapped, ensuring the proximal segment is anterior.
• Closure proceeds in an interrupted fashion, achieving a water-tight and tension-free anastomosis.
• Following a leak test, the chest is closed with the assistance of the CT surgeons.
• Postoperative care centers around avoiding neck extension. This can be achieved with sedation/paralysis for a prolonged period or chin-to-chest sutures.

Complications

Tracheal reconstruction is often successful, but complication rates can approach 40%.[1] Early identification and management of complications is key to long-term success. Aside from the expected complications of the surgery, specific complications regarding tracheal reconstruction can be separated into the following categories:[13]

Anastomotic

• Granulation tissue
• Restenosis or stricture
• Tracheomalacia
• Leak
• Dehiscence

Fistulas

• Tracheoinnominate
• Tracheoesophageal
• Tracheocutaneous

Miscellaneous

• Recurrent laryngeal nerve injury
• Dysphagia/aspiration
• Mediastinitis
• Pneumomediastinum
• Pneumothorax
• Prolonged ventilatory requirement
• Death

Clinical Significance

Tracheal stenosis is a rare complication resulting from either failed embryologic development or insults to the tracheal lumen. The most common causes are prolonged intubation and high cuff pressure, which result in stenosis. Mortality rates for severe tracheal stenosis are high, particularly in the pediatric population, and must be identified and treated early. Appropriate classification and grading will allow surgeons and care teams to triage and treat patients successfully and appropriately. The reconstructive plan must match the goals of care, and communication between the care team and the patient is essential. Surgical reconstruction through endoscopic or open approaches is generally successful. However, despite advances in surgical technique, complications are still prevalent and must be managed appropriately and expeditiously to prevent unwanted outcomes.

Enhancing Healthcare Team Outcomes

Tracheal stenosis requiring reconstruction is a rare anomaly that requires a dedicated multidisciplinary team to achieve success for the patient. While the surgeons (otolaryngology, cardiothoracic) are ultimately responsible for the surgical reconstruction, their success depends on a team. These patients require an extensive preoperative workup, and their clinical status must be optimized before surgery. Also, postoperative care is extensive. Critical care physicians, pulmonologists, gastroenterologists, anesthesiologists, nursing, speech and language pathologists, and care coordinators must work tirelessly to ensure the safety and well-being of the patient. Communication is key, which is why these patients should be managed exclusively through a multidisciplinary aerodigestive clinic where all these services are available.[8]