Anatomic variations of the round window niche: radiological study and related endoscopic anatomy

Pietro Canzi, Irene Avato, Marco Manfrin, Anna Maria Simoncelli, Marianna Magnetto, Elisabetta Rebecchi, Carmine Tinelli, Marinella Neri, Millo Achille Beltrame, Marco Benazzo

Research output: Contribution to journalReview articlepeer-review


Purpose: In the last decades, literature has shown an increasing interest in round windows (RW) anatomy due to its pivotal role in deafness surgery. The high variability of this anatomical region, with particular regard to the round windows niche (RWN), has been studied by several authors through different methods of investigation. The aim of the present research was to radiologically examine the morphological variability of the RWN and to link the imaging findings to the endoscopic view. Methods: High-resolution CT scans of 300 temporal bones without neuro-otological pathologies were retrospectively reviewed by 2 neuroradiologist and 1 ENT surgeon who independently evaluated the RWN morphological variations. To link the radiological to the endoscopic data, 45 cadaveric human temporal bones were submitted to a radiological evaluation and to an otoendoscopy conducted through a posterior tympanotomy approach. Results: Three variants of the RWN were detected on coronal CT scan reconstructions: 155 “cylindrical-type”, 97 “j-type” and 48 “truncated cone-type”. For each radiological type the endoscopic findings showed a specific endoscopic position of the RW chamber, which results in different degrees of RW membrane visibility when analysed through a posterior tympanotomy approach. Conclusions: To the best of our knowledge, this is the first description of the above-mentioned RWN radiological variations supported by endoscopic data. This study suggests an additional anatomical evaluation that could be useful to predict the RW membrane visibility through a posterior tympanotomy approach. Further studies are required to support the clinical implications of our observations.

Original languageEnglish
JournalSurgical and Radiologic Anatomy
Publication statusPublished - Jan 1 2019


  • Anatomic variation
  • Cochlear implant
  • Endoscopic anatomy
  • Middle ear
  • Radiological anatomy
  • Round window niche

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine
  • Radiology Nuclear Medicine and imaging


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