In the 1980s, two Austrian rhinologists added functional concepts of sinonasal mucociliary patterns to endoscopic endonasal surgical interventions, previously published by two German rhinologists. Thus was the birth of functional endoscopic sinus surgery. Today, this approach is the gold standard in sinonasal disease surgery. Why did a similar transition not occur in ear surgery?
Otologic surgery had been dominated by the operating microscope from the early 1920s by two German otologists. Early microscope use was slow, had limited vision, a small working distance, poor illumination, instability and lack of manoeuvrability. These issues were rectified and the operating microscope was used widely by the 1950s.
Functional endoscopic sinus surgery was increasing in use, and endoscopic ear surgery was being used as an adjunct to the microscope and as a primary treatment. There were, however, three key limitations that prevented its full transition to ear surgery. First, the light source converted significantly to heat at the endoscope tip, risking damage to critical structures, for example, the facial nerve. With newer xenon, and then LED light sources, there is minimal heat dissipation when using lower light source settings. Second, endoscopes small enough to fit in the middle ear had very limited magnification and field of view. A newer, smaller 3mm endoscope has been introduced. This allows sufficient space for simultaneous insertion of instrumentation through the ear canal, evenin small children. Finally, there were many issues relating to the endoscope’s camera. Single-chip cameras were prone to “redout” in small areas because of bleeding saturating the field and minimising identification of anatomical structures. These have been replaced with triple chargecoupled device cameras, without this effect occurring. High-definition video has replaced standard-definition, creating crisper, clearer pictures and improved image magnification. This makes it possible to see individual red blood cell clusters travelling through capillaries in the middle ear intra-operatively. International collaboration and adoption of this technology has now begun in earnest, with the formation of the International Working Group on Endoscopic Ear Surgery, and its first world congress in 2015. This technology is here to stay — but what does it mean to patients in practical terms?
Some argue that the endoscope is now indicated in any and all otologic surgical procedures. Previously, otological procedures were exclusively performed with the microscope. Recently, the endoscope has had limited use as an adjunct to the microscope to assess whether areas blindly dissected via the microscope were disease-free.
Many International Working Group members now claim to perform all otologic procedures endoscopically, mostly with microscopic guidance, but occasionally on its own. This technology is in its infancy and, with the goalposts constantly shifting, defining a clear set of indications is difficult. With time and more otologists using endoscopy, benefits and limitations will be better defined.