Office-based transtympanic endoscopy through the perforation made by laser-assisted myringotomy (LAM) has been introduced for diagnosis of ossicular interruption, stapes fixation, tympanosclerosis, congenital cholesteatoma, and perilymphatic fistula. Endoscopy of the middle ear reveals minor anomalies around the incudostapedial joint and the superstructure of the stapes. This procedure can be also applied to diagnose stapes fixation and perilymphatic fistula not diagnosed presurgically, and requires exploratory tympanotomy to make a definite diagnosis. Transtympanic endoscopy using LAM is a direct and reliable preoperative diagnostic method for abnormalities of the middle ear, offers better surgical indications and patient consultation, and is a potential alternative to exploratory tympanotomy.
Key points
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An endoscopic transtympanic procedure using laser-assisted myringotomy is a direct and reliable preoperative diagnostic method for abnormalities of the middle ear.
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This procedure is less painful and safe, and is easily performed even in young children in the outpatient clinic.
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This procedure can reveal minor anomalies around the incudostapedial joint and the superstructure of the stapes, which cannot be detected with standard high-resolution computed tomography.
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This procedure can be also applied to diagnose stapes fixation and perilymphatic fistula, which could not be diagnosed presurgically and for which exploratory tympanotomy has been necessary to make a definite diagnosis.
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This procedure offers better surgical indications and patient consultation, and is a potential alternative to exploratory tympanotomy.
Overview
To make a diagnosis of abnormality of the middle ear in a case of an intact tympanic membrane, exploratory tympanotomy has been necessary even when high-resolution computed tomography (CT) is applied to evaluate the condition of the middle ear. Office-based transtympanic endoscopy through the perforation made by laser-assisted myringotomy (LAM) has been introduced for the diagnosis of ossicular interruption, stapes fixation, tympanosclerosis, congenital cholesteatoma, and perilymphatic fistula. This procedure is effective and safe, and is a potential alternative to exploratory tympanotomy.
Overview
To make a diagnosis of abnormality of the middle ear in a case of an intact tympanic membrane, exploratory tympanotomy has been necessary even when high-resolution computed tomography (CT) is applied to evaluate the condition of the middle ear. Office-based transtympanic endoscopy through the perforation made by laser-assisted myringotomy (LAM) has been introduced for the diagnosis of ossicular interruption, stapes fixation, tympanosclerosis, congenital cholesteatoma, and perilymphatic fistula. This procedure is effective and safe, and is a potential alternative to exploratory tympanotomy.
Preoperative planning
Otoscopic Examination and Hearing Tests
A detailed otoscopic examination and precise hearing tests including audiometry, tympanometry, and auditory reflex are performed to make a diagnosis of a conductive hearing loss.
High-Resolution CT
High-resolution CT is applied to evaluate the condition of the ossicular chain, and the presence of the sclerotic foci, new bone formation, or cholesteatoma. However, the integrity of the ossicular chain and stapes superstructure are not optimally depicted at CT with image reconstruction in the standard axial and coronal planes. Small anatomic details of the ossicular chain, such as lack or subluxation of the incudostapedial (IS) joint or the interruption between crus and footplate, are very difficult to evaluate. In addition, stapes fixation has not to date been diagnosed presurgically.
A Set of Endoscopes
Rigid endoscopes with 0°, 30°, or 70° viewing angles (1.9 mm in the outer diameter; Storz, Tuttlingen, Germany) are used ( Fig. 1 ). Images are delivered to a monitor through a high-definition charge-coupled device camera (Storz) attached to the endoscope lens, and recorded.
