Endoscopic laser-assisted reshaping of collapsed tracheal cartilage: a laboratory study

Repair of anterior tracheal wall collapse is a common and troublesome problem encountered by the head and neck surgeon. The standard treatment calls for an open procedure with or without stenting, depending on the extent of the damage. To avoid the morbidity of the open procedure, a new concept of endoscopic cartilage reshaping was investigated in a laboratory animal study. It involved the application of 1.44-micron pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser at relatively low power to restructure without devitalizing cartilage. An in vivo study was done in six dogs to determine appropriate laser dosimetry in a model of tracheal wall collapse created by a tracheotomy. The deformed cartilage was treated endoscopically with a noncontact 1.44-micron Nd:YAG laser, at 2 to 4 W of power with a repetition rate of 20 Hz, in three animals. As a control, three animals had endoscopic cartilage incisions followed by stent placement. Six weeks postoperatively, both groups had an adequate airway lined by healthy mucosa. In the animals with stenting, however, there was stenosis formation due to scarring at both ends of the stent, with significant inflammatory response in the local area. This study shows that it is possible to use low-power laser energy to reshape cartilage without destroying its viability, and to restore the tracheal wall to a normal contour without ablation or vaporization. The reshaped cartilage will tend to retain its shape with functional elastic force, as seen in in vitro studies. These preliminary results are encouraging, and it seems reasonable to consider using the technique in selected clinical cases as an alternative to conventional open surgery.