[Helium-neon laser--a possibility for the topodiagnosis of tracheal stenoses]

Exact knowledge of the upper and lower border of a tracheostenosis is important for success or failure in a transverse resection of the trachea. Using an angular optical equipment of 90 degrees, the upper margin of the stenosis can be focussed endoscopically in case of localisation problems, and projected on the front side of the trachea by the helium-neon laser beam. Even in case of tracheal displacement caused by a tumour, or induration of the soft tissues of the neck due to x-rays, the helium-neon laser beam will be an important orientation aid.