Laser safety in head and neck cancer surgery

The use of trans-oral laser techniques for the resection of head and neck carcinomas has increased exponentially over the last four decades. Inadvertent laser damage to the patient or operating theatre staff is an acknowledged risk. However, no data exist to verify the safety margin of commonly employed precautions. The aims of this study was to assess the safety margins of protective strategies commonly adopted when using CO(2) lasers to resect tumours of the head and neck. A Sigmacon Acupulse Lumenis CO(2) laser was evaluated. The beam was focused to 2 mm diameter at 402 mm focal length. Gauze swabs, neurosurgical patties, surgical gloves, paper drapes and conventional endotracheal (ET) tubes were tested against the following laser variables: power, beam characteristics and angle of beam incidence (90 & 45°). Laser penetration time through the material under test was recorded in seconds (s). All the materials where tested dry and some, when appropriate, were tested wet. The mean of three recordings was calculated. The results demonstrated dry gauze swabs, neurosurgical patties and paper drapes provided 0 s protection at 2 W (lowest power). However, when wet, the laser failed to penetrate the swabs and neurosurgical patties, even after 180 s of continuous application. Gloves (single or double layer), and ET cuffs were penetrated in less than 1 s at 2 W. Time to penetrate a size 6.0 ET tube at 2 W continuous setting increased from <1 s at 90° to 42 s at 45°. These data are essential for anyone using CO(2) lasers for the resection of head and neck tumours. The importance of keeping laser consumables wet throughout the procedure is highlighted. The angle at which the laser hits the ET tube may impart some protection against airway fire but the data support the need to cover the ET tube with damp swabs or neuropatties when possible.