Tracheobronchial disruption (TBD) accounts for 0.5%-2.8% of blunt chest trauma[3]. The mechanism of TBD involves bulging traction, accelerated deceleration resulting in shear stress, or a sudden increase in intrathoracic pressure. These forces can work alone or in combination[4]. In blunt trauma, 75%-90% of TBDs are located within 2-3 cm of the carina and 60% within 1 cm[5].
Symptoms depend on whether there is communication between the injured airway and pleural cavity[6]. Subcutaneous emphysema and dyspnea are the most common initial signs of bronchial injury. Massive air leakage or persistent atelectasis may cause severe airway injury[7]. Our patient developed dyspnea, and massive air leakage in the chest tube after trauma, and tracheal injury was suspected.
Chest CT is superior to chest X-ray and can identify lesions and detect concomitant injuries. Sensitivity of CT imaging is 71%-100%[8]. However, despite bronchial injury, the connective tissue around the bronchus may remain intact and allow distal lung ventilation[6]. Due to surrounding tissue edema and bleeding, there are still some false-negative results, and CT-negative results do not rule out the presence of tracheal injury. In this case, chest CT showed right hydropneumothorax with right lung compression atelectasis but failed to show bilateral main bronchus rupture. There was no gas leakage on the left side due to the surrounding tissue encapsulation, and no imaging signs such as pneumothorax or atelectasis were observed.
Electronic fiberoptic bronchoscopy is a relatively accurate tool for diagnosing tracheobronchial injuries. Patients with persistent thoracic air leakage should undergo bronchoscopy immediately[9]. Electronic bronchoscopy revealed complete rupture of the right main bronchus from the carina and visible rupture of the left main bronchus in the carina. We confirmed the left and right main bronchi had ruptured completely from the protuberance. The distance between the distal end and the proximal end was about 2.5 cm and 1.6 cm, respectively. As bronchoscopy depends on personal experience, errors may occur.
Delayed diagnosis is defined as a definite diagnosis more than 48 hours after injury and is common in patients transferred from surrounding hospitals[10]; 25%-68% of patients are not diagnosed with tracheal injury within this time[11]. A delay in diagnosis results in scar tissue and obstruction of the bronchus by granulation tissue[12]. Therefore, timely diagnosis and treatment are essential to avoid scarring or granulation tissue hyperplasia, ensure repair of damaged bronchi, and maximize the retention of lung tissue. This child was transferred from another hospital, which contributed to delayed diagnosis; he was diagnosed on the 6th day after trauma. This greatly increased the probability of scarring or granulation tissue blocking the airway, which was a key factor in our decision to perform extracorporeal circulation-assisted surgery.
Patients with tracheal injuries have been reported to undergo repair under cardiopulmonary bypass[2]. Considering the following points, we chose extracorporeal circulation surgery: (1) If the trachea is completely transverse, the distal end may slip into the mediastinum[8]. Our intraoperative electronic bronchoscopy results are consistent with these findings. Disruptions at the bifurcation site may require a double-lumen tube or selective endobronchial intubation[13]. Multiple attempts at double-lumen intubation were unsuccessful. The distal trachea may slide into the mediastinum, and selective endobronchial intubation is difficult; this may lead to secondary injury[14]. (2) The best time for surgery is within 48 hours, allowing good repair and retention of lung tissue[15]. The child was diagnosed 6 days after the trauma, increasing the incidence of complications such as scarring and stenosis. Extracorporeal circulation surgery can guarantee good vision, provide good ventilation, ensure suture-free accuracy (as far as possible) to repair the damage rather than remove the lesion of lung tissue, and reduce postoperative complications. (3) There was a large amount of air leakage after intraoperative free bulge. It is difficult for ventilators to maintain tidal volume to avoid rapid cardiopulmonary deterioration and hypoxia, leading to severe cardiac arrest, etc. This life-threatening situation can be avoided only through emergency establishment of cardiopulmonary bypass to restore adequate oxygenation.
From our experience in dealing with congenital tracheal stenosis, we have summarized the following points: (1) The anterior wall of the broken end was sutured intermittently. Posterior wall anastomosis was difficult. We choose continuous suture of the posterior wall; it reduces the difficulty of suture, ensures the smoothness of the posterior wall, and reduces anastomotic dehiscence and granulation hyperplasia. (2) Excessive airway dissociation should be avoided to prevent vascular stripping, which may result in insufficient blood supply, anastomotic dehiscence, or nonunion. (3) Should be fully free under the condition of ensuring blood supply to avoid anastomotic tension is too high, resulting in anastomotic dehiscence. (4) Absorbable sutures and extratracheal knotting were used during surgery to avoid granulation hyperplasia caused by non-absorbable sutures.
Complications develop in up to 25.8% of patients, including early anastomotic dehiscence, or airway stenosis[5]. The incidence of stenosis and anastomotic dehiscence is 5%-6%[16]. Although diagnosis was delayed in our patient, intraoperative cardiopulmonary bypass was successful, and the sutures were exact and meticulous, avoiding complications. Postoperative chest CT and electronic bronchoscopy revealed satisfactory tracheal morphology.
In summary, the patient with completely fracture the bilateral main bronchi is rare. A median thoracotomy provides a better opportunity for selective repair. Extracorporeal circulation-assisted tracheoplasty is necessary for the treatment of bilateral main bronchial injuries involving an unstable respiratory status. We ensured adequate tracheal blood supply and complete dissociation during surgery. Intermittent sutures combined with continuous sutures were used to avoid complications such as anastomotic dehiscence and granulation.