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 treatme nt 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 a 1.44-mu m pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser at relatively low power to restructure without devitalizing cartilage. An in vivo st udy was done in six dogs to determine appropriate laser dosimetry in a model of tracheal wall collapse created by a tracheotomy. The deforme d cartilage was treated endoscopically with a noncontact 1.44-mu m Nd: YAG laser, at 2 to 4 W of power with a repetition rate of 20 Hz, in th ree animals. As a control, three animals had endoscopic cartilage inci sions followed by stent placement. Six weeks postoperatively, both gro ups had an adequate airway lined by healthy mucosa. In the animals wit h stenting, however, there was stenosis formation due to scarring at b oth ends of the stent, with significant inflammatory response in the l ocal 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 vapo rization. The reshaped cartilage will tend to retain its shape with fu nctional elastic force, as seen in in vitro studies. These preliminary results are encouraging, and it seems reasonable to consider using th e technique in selected clinical cases as an alternative to convention al open surgery.