Thermal Variations of Operative Microscopes in Otology.

Objectives (1) Measure temperature variations achieved by common otomicroscopes. (2) Raise awareness about possible thermal injury during otologic procedures with the advent of newer, high-powered otomicroscopes. (3) Describe optical technology that aims to reduce the potential for thermal injury. Methods A variety of otomicroscopes, with different light sources (ranging from 100W halogen to 300W xenon), were studied. Temperatures were recorded from human auricular skin with a noncontact infrared thermometer at various microscope light intensities and with use of irrigation. Multiple recordings were done at 5-minute intervals, and a working distance of 225 mm was maintained. Results Maximum skin temperatures were found to plateau relatively quickly, with higher-wattage xenon light sources reaching greater temperatures. One-way analysis of variance revealed significant differences in temperatures with decreased light intensities. High-wattage xenon light sources reached significantly higher temperatures when compared with halogen models. Discussion There is substantial variation in maximal skin temperatures reached by otomicroscopes. Temperatures can be decreased to safe levels by reducing light intensity and with use of irrigation. The maximum temperature obtained in our study was 41.4°C. Second-degree skin burns have been described with prolonged exposures to temperatures >44°C. Implications for Practice Given the described potential for burns, surgeons performing procedures on the ear and temporal bone should take precautions to diminish temperature in the operative field.

Clinical Diagnostic Accuracy of Otitis Media with Effusion in Children, and Significance of Myringotomy: Diagnostic or Therapeutic?

The specific aims of this prospective survey were to determine the accuracy of traditional diagnostic tools, such as pneumatic otoscopy, otomicroscopy, and tympanometry, and evaluate the usefulness of myringotomy as a diagnostic method; also to determine the significance of myringotomy in treating otitis media with effusion (OME). The status of middle ear of 51 children (85 ears) from November 2002 to February 2003 was examined using pneumatic otoscopy, otomicroscopy, and tympanometry, and the presence/absence of middle ear effusion was confirmed by myringotomy. The otomicroscopy was the most sensitive and specific one among three diagnostic tools. But, it had some false positive cases. This study failed to show the therapeutic efficacy of myringotomy. Otomicroscopy seems to have the potential to become the standard for diagnosis of OME and for validation of pneumatic otoscopy in children. However, when otoscopic, otomicroscopic findings and tympanogram of suspected ear show poor correlation, myringotomy can be used to confirm the presence of OME, as the diagnostic modality. As the therapeutic modality, we think that it is proper to limit indications of myringotomy to some selected cases.