内視鏡による耳小骨離断の診断と治療

Abstract

In conductive hearing loss with an intact ear drum, even though preoperative examinations including audiometry, tympanometry and CT scan are applied, exploratory tympanotomy is necessary to make an exact diagnosis of ossicular interruption and stapes fixation. In the exploratory tympanotomy, if an ossicular problem is detected during the procedure, it is usually followed by ossicular reconstruction surgery.Our current strategy for treatment of conductive hearing loss without tympanic membrane perforation is presented.The presurgical diagnosis is made in the outpatient clinic by transtympanic endoscopy through the circular and non-hemorrhagic perforation made by laser-assisted myringotomy (LAM). An endoscopic view of the ossicular chain through 30- or 70-degree angled tip endoscopes held immediately to the outer side of the perforation was obtained to diagnose conduction disturbance locus in conductive hearing loss cases. Precise preoperative diagnosis is useful for patient counseling, surgical indications and planning.When an ossicular interruption is diagnosed, endoscopic transtympanic tympanoplasty (ETT), a newly developed minimally invasive procedure, is planned. In the endoscopic visualization through the dry, circular myringotomy perforation using a 1.9mm diameter rigid angled endoscope, ossiculoplasty was performed by inserting a trimmed tragal cartilage through the myringotomy perforation. As opposed to conventional methods, this procedure does not require surgical exposure such as otosclerosis drilling and skin incision, and avoids the substantial risk of unnecessary injury to the chorda tympani. ETT for a disrupted ossicular chain is an adequate and minimally invasive procedure and should prove a useful surgical procedure in future endoscopic tympanoplasty.