April 03, 2021
Pediatric tracheal surgery is complex and requires an experienced multidisciplinary team that includes primarily specialists in pediatric cardiac surgery and pediatric otolaryngology, but also requires knowledgeable anesthesia, pulmonology and critical care staff. Nursing and respiratory therapy staff members also are essential. The team is typically involved with the preoperative evaluation, the operative approach and the postoperative management.
"Pediatric tracheal surgery may be required secondary to acquired tracheal disease, such as tracheal stenosis after tracheostomy or prolonged intubation, or congenital disease such as congenital tracheal rings, commonly associated with pulmonary artery sling," says Joseph A. Dearani, M.D., a cardiovascular surgeon at Mayo Clinic in Rochester, Minnesota.
Depending on the pathology, surgical management may include resection of the abnormal segment with an end-to-end anastomosis or a slide tracheoplasty. In general, when the pathology is less than 30% of the tracheal length (fewer than five tracheal rings), an end-to-end anastomosis is performed. Slide tracheoplasty can be used for more extensive pathology incorporating the majority of the trachea and even extending onto the bronchus.
Pulmonary artery sling is a rare vascular ring anomaly in which the left pulmonary artery arises from the right pulmonary artery and then passes around the distal trachea and right main bronchus coursing between the esophagus and trachea before exiting the pericardium to perfuse the lung.
This "sling" causes anterior external compression of the esophagus and compression of the trachea. External compression of the central airways in severe cases may cause a ball-valve effect resulting in hyperinflation of the right lung. The majority of these patients (75%) have concomitant complete, circumferential tracheal rings as opposed to the normal membranous tissue of the posterior trachea, resulting in further narrowing of the airway.
"Tracheal surgery in children has evolved over the last three decades," says Joshua P. Wiedermann, M.D., a pediatric otolaryngologist at Mayo Clinic in Rochester, Minnesota. "It was not until the 1960s that tracheal stenosis was classified and the first successful resection was reported."
Starting in the 1960s, Dr. Hermes Grillo led pioneering work at Boston Children's Hospital examining tracheal anatomy and developing techniques to improve outcomes of tracheal resection. Many of the advances in this field began with the first successful pulmonary artery sling repair in 1953, followed by pericardial patch tracheoplasty in 1982, and then the "autograft" technique in which a piece of the patient's own trachea was used for the reconstruction. In more recent years, the slide tracheoplasty has become the established technique for long-segment tracheal pathology.
Slide tracheoplasty is performed via a median sternotomy with the use of cardiopulmonary bypass, which provides ventilation and oxygenation without the need for cross-table ventilation. Any intracardiac lesions are repaired while on cardiopulmonary bypass prior to opening the trachea. Repeat bronchoscopy is performed to approximate the length of the tracheal pathology.
The trachea is dissected free with attention to preservation of its blood supply posterolaterally. Once the trachea has been mobilized, a needle is inserted at various points through the trachea with simultaneous bronchoscopy to confirm the superior and inferior extent of resection required.
In slide tracheoplasty, the established technique for long-segment tracheal pathology, two counter incisions are made.
The trachea is then sharply entered at the midpoint of the stenotic segment, and the trachea is transected. In the case of a slide tracheoplasty, two counter incisions are made with the one on the superior portion of the trachea performed anteriorly and the inferior portion of the trachea performed posteriorly. Each incision continues until normal trachea is encountered. The corners of these incisions are rounded and the two portions are slid together such that the trachea becomes half as long but with a twofold increase in diameter. The tracheal segments are then sutured together with attention to create a tension-free repair.
The resultant tracheal anatomy is examined intraoperatively via bronchoscopy to ensure a satisfactory result, the airways are suctioned, and the patient is reintubated. The repair is tested by filling the mediastinum with saline and providing progressively increased airway pressure to a maximum of 30 mm Hg. Once the repair has been confirmed to be satisfactory, the patient is weaned from cardiopulmonary bypass.
Tracheal resection with end-to-end anastomosis
Tracheal resection with end-to-end anastomosis is performed in cases with pathology less than 30% of the tracheal length.
In cases with pathology less than 30% of the tracheal length (fewer than five tracheal rings), the trachea is mobilized and the extent of the pathology is similarly localized using bronchoscopy. The abnormal tracheal rings are resected and end-to-end anastomosis is performed.
The resultant tracheal repair is examined with bronchoscopy and the patient is similarly suctioned and reintubated, the anastomosis is tested, and the patient is weaned from cardiopulmonary bypass. Short, isolated cervical segments often do not require sternotomy or cardiopulmonary bypass.
Pulmonary artery sling repair with concomitant complete tracheal rings uses the tracheal surgical techniques detailed above; however, the left pulmonary artery reimplantation into the distal main pulmonary artery is performed prior to the tracheal repair.
Care is taken to trim the length of the left pulmonary artery to ensure it does not kink in its course to the hilum. Priorities during the postoperative management include maintaining a tension-free repair, adequate pulmonary hygiene, and prevention and management of granulation tissue at the anastomosis. While some groups have routinely used a "chin" or "Grillo" stitch to prevent neck extension and resultant tension on the anastomosis, this is not felt to be necessary by most groups involved with tracheal surgery.
"Results of tracheal surgery in experienced centers with a multidisciplinary team have been excellent and continue to improve for a very challenging population," says Elizabeth H. Stephens, M.D., Ph.D., a cardiovascular surgeon at Mayo Clinic in Rochester, Minnesota. In a study published in Annals of Thoracic Surgery in 2020 by Dr. Stephens, of 41 patients with a median age 4.1 months, including 22% who required intracardiac repairs and 20% who had lung agenesis or severe hypoplasia, there were three patients with an early mortality (one from respiratory failure, one with liver failure secondary to biliary atresia, and one secondary to aortic valve endocarditis). There was one late death secondary to sepsis.
"Interestingly, those with lung hypoplasia or agenesis did not experience worse outcomes, but these patients were more symptomatic prior to surgery, had a longer length of stay and longer duration of mechanical ventilation," says Dr. Stephens. Midterm follow-up was available on 26 of the 38 survivors, with a mean of 4.6 plus or minus 5.8 years. There were no re-operations in this follow-up period.
Pediatric tracheal surgery is a challenging field requiring the close collaboration between the pediatric cardiac surgeons, a pediatric otolaryngology airway specialist and a multidisciplinary team. In tertiary care centers with comprehensive expertise, the current techniques of simultaneous tracheal and cardiac repairs have yielded excellent early and late results.
For more information
Backer CL, et al. A history of pediatric tracheal surgery. World Journal for Pediatric Congenital Heart Surgery. 2010;1:344.
Stephens EH, et al. Pediatric tracheal surgery: A 25-year review of slide tracheoplasty and tracheal resection. Annals of Thoracic Surgery. 2020;109:148.