09-11, 07:00– (Europe/Istanbul), Otology 4
Conventional mastoidectomy requires a large postauricular incision, with elevation of the auricle to widely expose the temporal bone surface. The mastoid air cells are then extensively drilled using several types of burrs, creating a mortar-shaped cavity toward the deep portion. During this process, the surgeon repeatedly adjusts the microscope to maintain a clear view while preserving critical structures: the posterior canal wall is thinned and preserved anteriorly; the dura superiorly, sigmoid sinus posteriorly, and the lateral semicircular canal and facial nerve in the deeper region must all be safely exposed and protected. This traditional and well-established technique represents the foundation of microscopic ear surgery. However, is complete mastoidectomy truly necessary even in cases with well-developed, normal mastoid air cells? The mastoid mucosa possesses gas-exchange functionality. Because ear surgery had long been limited to microscopy, the question of whether it is appropriate to sacrifice normal mastoid air cells has not been sufficiently explored. In contrast, the use of endoscopes in ear surgery has advanced remarkably. Endoscopes provide a very wide field of view due to their wide-angle lenses. Unlike the microscope, whose lens remains outside the temporal bone and therefore distant from the target, the endoscope places the lens inside the temporal bone, enabling bright, magnified, close-up visualization. Endoscopic instrumentation is particularly advantageous for disease involving the mesotympanum, retrotympanum, protympanum, and hypotympanum, where it often outperforms the microscope. Access to the epitympanum can also be achieved through transcanal atticotomy (TCA). We developed percutaneous endoscopic ear surgery (PEES), which involves making a 2 cm incision behind the ear during mastoidectomy and performing a keyhole bone incision of approximately 1 cm toward the mastoid sinus using an electric drill under water irrigation (Otol Neurotol. 2025 Jun 1;46(5):532-538.). Instead of the traditional mortar-shaped drilling, PEES allows a dome-shaped mastoidectomy under endoscopic guidance. A microscope, which only provides a straight-line view, cannot ensure visualization through such a narrow keyhole; however, the endoscope delivers wide, bright visualization within the mastoid cavity. In conventional microscopic mastoidectomy, creating a large surgical field is essential to avoid damage to vital structures in the temporal bone. In PEES, this safety is maintained through the combined use of a navigation system. Cholesteatomas extending from the epitympanum to the antrum—lesions that require TCAA in TEES—represent excellent indications for PEES. After reaching the antrum with PEES, further selective drilling is performed to expand the working space. The cholesteatoma matrix is dissected from the antrum side and pushed toward the epitympanum. If necessary, the contents are reduced through the area of pars flaccida retraction. Subsequently, TCA is performed to remove the cholesteatoma completely, followed by scutum reconstruction using cartilage. As a result, high-level canal wall reconstruction becomes unnecessary, and only scutum reconstruction is required. By incorporating augmented reality guidance within the navigation system, Image-Guided PEES (IGPEES) ensures safety while enabling precise minimally invasive surgery. IGPEES represents a next-generation, innovative extension of TEES. This presentation will outline the principles of otologic navigation systems and provide an overview of PEES and IGPEES techniques.
To demonstrate the feasibility of recent image-guided systems for TEES.
1990: Graduated from Kansai Medical University
1995 Assistant Professor, Department of Otorhinolaryngology, Kyoto Prefectural University of Medicine
1996: Director, Department of Otorhinolaryngology, Fukuchiyama City Hospital
1998: Director, Department of Otorhinolaryngology, Nantan General Hospital
2005: Deputy Director, Department of Otorhinolaryngology, Japanese Red Cross Kyoto Daini Hospital
2018: Director, Department of Otorhinolaryngology and Tracheoesophageal Surgery, Japanese Red Cross Kyoto Daini Hospital
Job titles：
Clinical Professor, Kyoto Prefectural University of Medicine
Representative, Japan Otorhinolaryngologists Association in Kyoto
Representative, Kyoto Temporal Bone Surgical Technique Study Group
Member, Japanese Working Group on Endoscopic Ear Surgery
Member, Japanese Working Group on Robotic Ear Surgery
Member, Tympanic Regeneration Surgical Technique Study Group
Qualifications：
Specialist in Japanese Society of Otorhinolaryngology-Head and Neck Surgery
Specialist Training Instructor in Japanese Society of Otorhinolaryngology-Head and Neck Surgery
Instructor in Otologic Surgery Certified by Japanese Society of Otorhinolaryngology-Head and Neck Surgery
1994- Kyoto University, School of Medicine
2000- Kyoto University Hospital, Otolaryngology- Head and Neck Surgery, Resident
2001- Kurashiki Central Hospital, Otolaryngology- Head and Neck Surgery, Clinical Staff
2004- Nishi-Kobe Medical Center Hospital, Otolaryngology- Head and Neck Surgery, Clinical Staff
2006- Kyoto University, Graduate School of Medicine
2008- Karolinska Institute, Department of Physiology and Pharmacology Division of Experimental Audiology, Resercher
2010- Department of Otolaryngology, Tenri Hospital, Clinical Staff
2011- Department of Otolaryngology, Tenri Hospital, Deputy Director
2016- Department of Otolaryngology, Tenri Hospital, Director
2021- Department of Otolaryngology - Head and Neck Surgery, School of Medicine, Fujita Health University, Associate Professor
2023- Department of Otolaryngology - Head and Neck Surgery, University of Occupational and Environmental Health, Japan, Professor and Chair
Seiji Kakehata, M.D., Ph.D. is best known for his work in pioneering endoscopic ear surgery in his home country of Japan and around the world. He served as Professor and Chair of the Department of Otorhinolaryngology-Head and Neck Surgery at Yamagata University Faculty of Medicine until March of 2023 after which he became Professor Emeritus. In May of 2023, he opened the Endoscopic Ear Surgery Center in the Ota General Hospital in Kawasaki Japan to make TEES more accessible to the wider public. He is also the immediate past Chair of Board of Directors, Japan Otological Society. He is a director of the Japanese Society of Otorhinolaryngology-Head and Neck Surgery. In addition, he is a founding board member of the International Working Group on Endoscopic Ear Surgery (IWGEES) and its immediate past president as well as the president of the Pan-Asia Working Group on Endoscopic Ear Surgery (PAWGEES).
Dr. Kakehata’s clinical interests include minimally invasive endoscopic ear surgery, conductive and sensorineural hearing loss, and facial nerve palsy. Dr. Kakehata’s research has focused on cochlear hair cell physiology and hearing regeneration. His funded research includes the study of outer hair cell motility, effects of cholesterol alterations on outer hair cells, regeneration of the facial nerve, and regeneration of auditory nerve fiber growth and synapse formation after ear injury.
Dr. Kakehata hosted the 4th World Congress on Endoscopic Ear Surgery in 2022 and is the president-elect of the 36th Politzer Society Meeting to be held in 2028 in Kyoto. He organized and conducted the first endoscopic ear surgery courses in Asia and has continued to host an annual hands-on course since 2012. He has delivered numerous presentations at regional and national meetings in Japan, as well as at international conferences and courses, particularly in the field of endoscopic ear surgery.
Prof. In Seok Moon is a leading expert in otologic surgery and a pioneer in endoscopic ear procedures. His contributions to minimally invasive endoscopic techniques help reduce recovery time and preserve hearing, positioning him at the forefront of otolaryngology. He also advances surgical techniques for acoustic neuroma, external auditory canal cancer, and hearing implants. As a professor of Yonsei University and the director of the Surgical Anatomy Education Center, he is dedicated to educating young doctors and medical students.
<u>Education</u><u> & Training</u>
Yonsei University College of Medicine, Bachelor(1999), Master(2007), PhD(2011)
Harvard Medical School Postdoctoral fellow (2017-2018)
<u>Positions and Career</u>
Professor, Yonsei University College of Medicine
Director, Surgical Anatomy Education Center, Yonsei University College of Medicine
Chairman, Department of ENT, Gangman Severance Hospital (2021-2022)
<u>Academic committees</u>
Present, Korean Tinnitus Study Group
General Secretary Korean Skullbase Society
Academic Chair, 36th Politzer Society meeting 2026
Academic Chair, 10<sup>th</sup> International Vestibular Schwannoma Congress 2027
General Secretary, 7<sup>th</sup> World Congress of Endoscopic Ear Surgery 2028
Academic Chair, Korean Society of ORL-HNS (2022-2023)
General Secretary, Korean Pediatric Society of Otorhinolaryngology (2021-2022)