Hearing Results After Hypotympanotomy for Glomus Tympanicum Tumors

Objective: We postulate, that glomus tympanicum tumors (GTTs) may be safely removed without interference with the ossicular chain via a hypotympanotomy approach. Study Design: Prospective, nonrandomized anatomic and clinical study. Setting: Tertiary referral center. Patients: All 17 patients between 1989 and 2009 with GTTs without involvement of the lumen of the jugular bulb. Interventions: We used a modified hypotympanotomy approach. Our technique is a modification of the one first published by Shambaugh (1955). Pure-tone audiograms were performed in all patients. Preoperative and postoperative audiograms were modeled in a linear mixed model evaluating hearing threshold for air and bone conduction and air-bone gap at 500, 1,000, 2,000, and 3,000 Hz. In an effort to preserve the normal sound conducting apparatus and hearing, we used a retroauricular approach, exposing widely the jugular bulb, the carotid artery, the protympanum, and even the bony part of the Eustachian tube via a hypotympanotomy. Three formalin-fixed and one macerated temporal bones were dissected step by step under the operating microscope to demonstrate the approach in cadaver dissections. Main Outcome Measure: To evaluate if GTTs can be completely resected without interference with the ossicular chain to improve conductive hearing loss. Results: We found a substantial improvement of hearing threshold after surgery at all frequencies in air conduction. For bone conduction, there was only a slight gain within random variation. The air-bone gap decreased significantly after surgery. Conclusion: Our approach demonstrated a safe avenue for complete tumor removal without interference with the continuity of the ossicular chain.