Objectives/hypothesis: In conductive hearing loss (HL), even though preoperative examinations including audiometry, tympanometry, and computed tomography (CT) scan are applied, exploratory tympanotomy is necessary to make an exact diagnosis of ossicular interruption and stapes fixation. Precise preoperative diagnosis would be useful for patient counseling, surgical indications, and planning. The advantages of office-based OtoScan laser-assisted myringotomy (LAM), which makes a circular and non-hemorrhagic perforation, prompted us to investigate other uses of LAM in addition to ventilation and drainage of the tympanic cavity. To make presurgical diagnosis in conductive HL, endoscopes with an outer diameter of 1.7 or 1.9 mm were used to inspect the middle ear pathology through perforations with a diameter of 2 mm made by LAM.
Methods: In the outpatient clinic, a circular perforation with a diameter of 2 mm was made in the tympanic membrane with LAM. An endoscopic view of the ossicular chain through a 70degrees angled tip endoscope held immediately to the outer side of the perforation was obtained to diagnose conduction disturbance loci in conductive HL cases.
Results: Ossicular chain abnormalities were easily and safely detected by clean endoscopic views obtained through a nonhemorrhagic circular perforation. When necessary, insertion of the tip of the endoscope into the tympanic cavity provided additional views of epitympanum.
Conclusion: We suggest that transtympanic endoscopy through the perforation made by LAM is an effective and safe office-based procedure for diagnosis in conductive HL cases and could be an alternative procedure to replace exploratory tympanotomy.