Hearing restoration in NF2 patients and patients with vestibular schwannoma in the only hearing ear: report of two cases.

OBJECTIVE: To explore audiologic outcome of auditory brain stem implantation (ABI) and cochlear implantation (CI) in NF2 patients and patients with vestibular schwannoma (VS) in the only hearing ear. PATIENTS AND METHODS: Study includes retrospective analysis of 2 cases. One is totally deaf patient due to NF2, and the other one is totally deaf due to VS development in only hearing ear. Tumor was removed by retrosigmoid approach in NF2 patient and ABI was performed simultaneously. For the VS in only hearing ear case, tumor was removed by translabyrinthine approach and CI was performed simultaneously. RESULTS: ABI patient showed quite well outcome during the 15 months of follow-up. She has 25 dB hearing threshold at speaking frequencies. She developed open set speech discrimination with 87.5% word discrimination score, and 70% sentence discrimination score. She uses device daily manner, she can use telephone. For CI patient, outcome is not perfect but satisfactory. She couldn't develop open set speech discrimination during the 18 months of follow-up. She has 67% the disyllabic words recognition score (close set). She is daily user of device. CI improves quite well lip reading. CONCLUSION: ABI and CI are the two options to restore hearing in VS caused deafness. We advocate giving every effort to preserve cochlear nerve during the VS resection and place CI simultaneously. However if it is not possible to preserve cochlear nerve during surgery, ABI is also a good alternative for hearing restoration.

Iatrogenic carotid artery pseudoaneurysm presenting with conductive hearing loss.

Pseudoaneurysms of the intracranial internal carotid artery may occur in the setting of carotid artery dehiscence, due to trauma, invasive tumors, or as a complication of surgery. The rare surgical complication of carotid artery laceration in the petrous segment may occur during myringotomy procedures, middle ear operations, or petrous temporal bone surgery. We report a 28-year-old female patient, a case of internal carotid artery pseudoaneurysm as a complication of middle ear surgery. On her follow-up, computed tomography of the temporal bone demonstrated a dehiscent carotid artery, and a pseudoaneurysm involving the left petrous internal carotid artery was found in the cerebral angiography. She was managed by endovascular means.

Comparison of head rotation versus head elevation methods for vestibular evoked myogenic potentials by using logon stimulus.

OBJECTIVES: To compare vestibular evoked myogenic potentials (VEMP) between two different methods, head rotation (HR) with unilateral recording and head elevation (HE) with bilateral simultaneous recording. SUBJECTS AND METHODS: Twenty-eight healthy children (56 ears) were involved in the study. The subjects were tested in two different positions: head rotation (HR) method and head elevation (HE) method. Right- and left-side recordings were made separately in HR method and simultaneously in HE method. Logon type stimulus with 120dB Hl intensity was used to trigger VEMPs in both methods. RESULTS: The response rate was 80.4% for HR method and 89.3% for HE method (p>0.05). There was no significant difference between the two groups with respect to P1 latency, N1 latency, and P1-N1 interval. The mean P1-N1 amplitude of HE method was higher than HR method (p<0.05). There were very strong positive correlations between two methods regarding N1 latency and P1-N1 interval (r: 0.849 and 0.841, respectively). CONCLUSION: Bilateral simultaneous VEMP recording in head elevation position by using logon stimulus is a practical way to evaluate vestibulocollic reflex in children and it gives superior results than unilateral recording with head rotation position.