200µm glass fibres for minimally invasive laser procedures in paranasal sinus surgery

Objective: To investigate the suitability and power capacity of thin (200 µm) quartz glass fibres in contrast to conventional fibres (400-600 µm) for laser resection of recurrent nasal polyps. Material and methods: Different quartz glass laser fibres (200 µm, new; 200 µm, re-used and 600 µm, new) were coupled to a Neodymium:YAG laser emitting at 1064 nm in continuous wave (cw) mode. We compared the nominal power (W) with the actual output at the fibre tip by a laser power meter. We resected nasal polyps in patients using both 200 and 600 µm fibres with rigid and flexible applicators. Results: For 200 µm fibres, power settings of 14 W resulted in carbonisation of the superficial cladding. The laser power measured at the fibre tip corresponded to the nominal settings for the new 200 and 600 µm fibres. Fifty percent power loss due to inhomogeneous beam geometry was recorded with the re-used fibre. Histology revealed a deeper coagulation zone for the 600 µm compared to the 200 µm fibre. Conclusion: 200µm quartz glass fibres display reliable transmission properties for power settings up to 10 W in cw mode. Their greater flexibility reduces the risk of unnoticed power loss or fibre breakage at small bending radius.