[Preliminary exploration of CT evaluation system for tracheostomy of cervical or upper thoracic kyphosis]

Objective:To evaluate the applicability of tracheostomy tube for patients with cervical or upper thoracic kyphosis, and establish a preoperative imaging evaluation system for tracheotomy in patients population. Methods:The three-dimensional（3D） geometry of the neck were reconstructed using computed tomography scans for patients with cervical or upper thoracic kyphosis. The local kyphosis angle of vertebral body, the total kyphosis angle of cervical spine, the distance between trachea and skin and the height of innominate artery were measured. 3D models of tracheostomy tubes were generated using geometric modeling software. Tracheostomy was simulated in the virtual 3D models. The distance between the tube tip and the inner tracheal wall was measured to analyze whether the tracheostomy tube was suitable for patients with cervical or upper thoracic kyphotic deformity. Results:64% of patients with cervical or upper thoracic kyphosis were not fitted with the tracheostomy tubes. The Pearson coefficient is 0.927 and R² is 0.860 between the angle of cervical kyphosis and the distance between the cannula and tracheal wall. According to the ROC curve analysis, when the angle of cervical kyphosis exceeded 33.32 degree, the tracheostomy tube became unsuitable, with both sensitivity and specificity equal to 1. Conclusion:The tracheostomy tube is not suitable for the majority of patients with cervical or upper thoracic kyphosis. This study established a preliminary preoperative imaging evaluation system for difficult tracheotomy in patients with cervical or upper thoracic kyphosis, and proposed a 33.32 ° cervical total kyphosis angle as a reference standard for tracheostomy tube adaptation during tracheotomy for patients with cervical or upper thoracic kyphosis. In addition, this study provides initial validation that three-dimensional reconstruction and preoperative planning of tracheotomy position can avoid postoperative complications caused by poor position of the tube in these patients.