Objective To investigate the effectiveness of various materials in reconstruction of laryngotracheal framework and to analyze the advantages, disadvantage, and indication of each material. Methods The cl inical data were retrospectively analyzed, from 337 laryngotracheal stenosis patients undergoing laryngotracheal framework reconstruction with various materials between October 1986 and October 2006. There were 229 males and 108 females aged from 2 to 54 years (median, 23.5 years). According to Cotton’s grading criteria for laryngotracheal stenosis, there were 94 cases of grade II, 218 cases of grade III, and 25 cases of grade IV, and all accompanied by laryngotracheal framework defect of 1-5 cm. The costal cartilage autograft was performed in 157 cases, thyroid cartilage graft in 27 cases, nasal septal cartilage graft in 8 cases, sternohyoid myocutaneous rotary door flap graft in 104 cases, hyoid bone flap of sternocleidomastoideus graft in 7 cases, musculo-periosteum flap of sternocleidomastoideus with clavicular periosteum in 21 cases, hydroxyapatite artificial tracheal ring graft in 10 cases, and pedicle myocutaneous flap with “C” shape nickel-titanic alloy net graft in 3 cases. Silastic T-tube was used after reconstruction for 6-12 months. Results Infection occurred in 5 cases and the incisions healed by second intention, the others achieved healing of incision by first intention. Intratracheal granulation formation occurred in 23 cases and choke when taking food in 6 cases; they were all cured after symptomatic treatment. After operation, 4 cases failed to be followed up and 12 cases did not recover, including 6 cases of costal cartilage autograft, 1 case of hyoid bone flap of sternocleidomastoideus graft, and 5 cases of sternohyoid myocutaneous rotary door flap graft. A total of 321 patients were followed up for 1-10 years (mean, 3.5 years). The patients had no laryngotracheal restenosis with good swallowing function and respiratory function. Conclusion Different materials of laryngotracheal framework reconstruction have advantages and disadvantage respectively. The appropriate material should be selected according to the special details of pathological change, and the satisfactory curative effect may be obtained.
Stent migration is one of the common complications after tracheal stent implantation. The causes of stent migration include size mismatch between the stent and the trachea, physiological movement of the trachea, and so on. In order to solve the above problems, this study designed a non-uniform Poisson ratio tracheal stent by combining the size and structure of the trachea and the physiological movement of the trachea to improve the migration of the stent, meanwhile ensuring the support of the stent. In this study, the stent corresponding to cartilage was constructed with negative Poisson's ratio, and the stent corresponding to the circular connective tissue and muscular membrane was constructed with positive Poisson's ratio. And four kinds of non-uniform Poisson's ratio tracheal stents with different link lengths and negative Poisson's ratio were designed. Then, this paper numerically simulated the expansion and rebound process of the stent after implantation to observe the support of the stent, and further simulated the stretch movement of the trachea to calculate the diameter changes of the stent corresponding to different negative Poisson's ratio structures. The axial migration of the stent was recorded by applying different respiratory pressure to the wall of the tracheal wall to evaluate whether the stent has anti-migration effect. The research results show that the non-uniform Poisson ratio stent with connecting rod length of 3 mm has the largest diameter expansion in the negative Poisson ratio section when the trachea was stretched. Compared with the positive Poisson's ratio structure, the axial migration during vigorous breathing was reduced from 0.024 mm to 0.012 mm. The negative Poisson's ratio structure of the non-uniform Poisson's ratio stent designed in this study did not fail in the tracheal expansion effect. Compared with the traditional stent, the non-uniform Poisson's ratio tracheal stent has an anti-migration effect under the normal movement of the trachea while ensuring the support force of the stent.