Laser resistance of expandable metal stems in interventional bronchoscopy:An experimental evaluation

Backgound and Objective: Nd-YAG non-contact laser therapy is used to elimin ate recurrent tumor tissue within airway stems. This study was performed to determine maximum exposure time until the stent wire is destroyed as well as exposure time necessary to deliberately fracture the wire mesh. Study Design/Materials and Methods: Strecker stems, Wallstents, and Nitinol Accuflex stems were implanted into pig bronchi. Then Nd-YAG laser light wa s directed to the stent wires at different power levels. Portions of the st ent surrounded by bronchial tissue as well as bare wires were investigated. Results: The Strecker stent and the Wallstent revealed a considerably highe r laser resistance than did the Nitinol Accuflex stent. At 15 W, minimum ex posure time until wire destruction was 4.6 and 6.3 s for the Strecker stent and the Wallstent respectively. In contrast, the Nitinol Accuflex stent to lerated only 1.7 s. Conclusions: Laser therapy with bronchial wire stems can be carried out at low power levels. It should, however, be avoided in the case of Nitinol Acc uflex stems due to their low heat tolerance. (C) 2001 Wiley-Liss, Inc.