Morphological changes induced by extensive endobronchial electrocautery

Due to recent improvements of safety conditions for therapeutic devices, el ectrocautery is being considered with renewed interest in the field of ther apeutic bronchoscopy The efficiency of this technique for destructing intra luminal tumours is well documented and makes it an attractive alternative t o Yttrium aluminium garnet (YAG) laser photo-coagulation. Little is known, however, about the morphologic changes induced by electrocautery within the bronchial wall structures. This information is, however important since el ectrocautery: has been proposed as an alternative to other techniques to tr eat superficial tumours of the bronchial wall. Soft coagulation, with autostop, using two different power setting (40 and 120 W), produced by a new generation of high frequency voltage regulated ge nerators was applied circumferentially to the trachea or left main bronchus , in a series of 52 piglets. Early (48 h) and late effects (6 weeks) were a ssessed through gross examination (bronchoscopy and autopsy) and light micr oscopy Early effects of electrocautery included coagulation necrosis of the mucosa only and intense acute inflammation extending deep into the bronchial stru cture, The inflammatory phase progressively resolved while extensive transm ural fibrosis and deterioration of the cartilage plates developed. The natu re and extent of these Lesions did not depend upon the energy delivered (40 W versus 120 W). Retractile scar formation and loss of cartilaginous suppo rt then produced iatrogenic secondary stenoses. These results do not question the use of electrocautery to palliate endolum inal tumours but should make operators careful when treating extensive infi ltration of the bronchial wall.