Introduction
Endoscopic ear surgery (EES) has become an internationally recognized surgical method to treat all kind of middle ear disease. Due to its wide-angled view and the possibility to use angled lenses to access hidden anatomical areas of the middle ear, it is a suitable technique, especially in the treatment of cholesteatoma1-3. Recent studies confirm the efficacy and suitability of these technical refinements offering a minimal-invasive surgical method to remove cholesteatoma, minimize the amount of residual tissue and prevent recurrences3-6. Due to the locally invasive and destructive behavior of middle ear cholesteatoma, detection and radical removal of even microscopic residuals is required to prevent re-growth and complications7.
Despite technical advancements regarding the visual control of the middle ear as offered by the endoscopic approach, the complete eradication of the squamous cell matrix from the middle ear is still a surgical challenge. Especially in diffusely infiltrating cholesteatoma it may be difficult removing the cholesteatoma-sac “en-bloc”. Moreover, the quest for possible cholesteatoma remnants is often time consuming and impacts on surgical time.
To improve the detection of disease, digital technologies to enhance the signal visible on the screen have been developed8. As an example, narrow band imaging (NBI) technology by Olympus uses a filter, enabling narrow band light to penetrate tissues at different depths, whereby the superficial subepithelial microvascular pattern can be recognized8,9. Several studies have shown a significant added value in detection of neoplasms in the larynx, oro-hypopharynx10,11.
Similarly, the Storz Professional Image Enhancement System (SPIES), allows the surgeon to use four modalities of digital image modifications in addition to traditional white light during endoscopic surgeries. For increased tissue contrast, spectra A and spectra B use shade shift and swap, clara enables homogeneous illumination and chroma causes a contrast enhancement as well as an improvement of the image sharpness. In the context of cholesteatoma surgery, the use of this digital image enhancement (DIE) technology was also applied to EES. So far, in a small case series on forty-five patients reported by Lucidi et al. (2020), an added value in cholesteatoma detection was supposed8. Therefore, we aim to investigate possible benefits and limitations of the SPIES in EES. We hypothesize an increased sensitivity regarding cholesteatoma detection by using DIE technologies.