Is virtual endoscopy of the middle ear useful?

Virtual endoscopy is a relatively new imaging technology in otology, and therefore data on its efficacy in clinical situations are limited. We conducted a prospective study to evaluate the clinical relevance of radiologic diagnoses based on virtual endoscopy of the middle ear. Our patient population was made up of 30 adults who were scheduled to undergo surgery to correct conductive hearing loss of unknown etiology. Virtual endoscopy was performed on three-dimensional images that were constructed from images obtained with conventional two-dimensional computed tomography (CT). Findings on virtual endoscopy were then compared with the subsequent surgical findings. Virtual endoscopy suggested a middle ear pathology in 19 patients and a normal middle ear in 11 patients. Postoperatively, we found that the virtual diagnoses correlated moderately well with the surgical findings in the group of patients with predicted pathology; 13 of these 19 patients were found to have middle ear problems such as ossicular chain anomalies, otosclerosis, and cholesteatoma (positive predictive value: 68%). However, among the 11 patients whose middle ear structures were radiologically predicted to be normal, only 2 had negative middle ear findings on surgical exploration; of the remaining 9 patients, 8 had otosclerosis and 1 had malleus fixation (negative predictive value: 18%). Thus, the sensitivity and specificity of virtual endoscopy were 59 and 25%, respectively. Virtual endoscopy provides images from a surgeon's perspective, and so it has the potential to be useful in the preoperative evaluation of the middle ear cavity. With ongoing advancements in computer systems and imaging techniques, the cost, reliability, and efficacy of virtual endoscopy may improve. However, further clinical validation and cost-benefit analysis are required before we can determine if it has any additional advantages over conventional two-dimensional CT.

Short electrode insertion in cochlear implantation: speech perception performance of Cantonese-speaking subjects.

CONCLUSIONS: Subjects with cochlear ossification derived benefits in terms of speech performance similar to those of the non-ossified group. It is thus recommended that the insertion of short electrode arrays should be considered an alternative choice for patients with cochlear ossification. OBJECTIVE: Cochlear ossification has been recognized as a major obstacle to the full insertion of a multichannel cochlear implant electrode array. To alleviate the technical difficulty of placing a standard electrode array and the possibility of causing undesirable trauma to the cochlea, a newly designed electrode array with the same number of electrodes compressed into a shorter length has been made available. The aim of the present study was to examine the speech perception performance of patients implanted with the MED-EL C40+S compressed electrode array and to compare their results with those of matched groups implanted with the MED-EL C40+standard electrode array. MATERIAL AND METHODS: One pre-lingually and two post-lingually deaf subjects using short electrode arrays were matched with three groups of subjects using standard electrode arrays. The pre- and postoperative speech perception scores were evaluated. RESULTS: All three subjects using compressed electrode arrays achieved speech perception scores comparable to those of matched subjects using standard electrode arrays. There was also a tendency for the subjects to show similar patterns of speech perception scores as a function of the difficulty of the tests.

Radiation-induced petrous internal carotid artery aneurysm.

Iatrogenic internal carotid artery aneurysm is a rare complication of irradiation. There are few reported cases in the literature. A case of radiation-induced petrous internal carotid artery aneurysm in a patient with nasopharyngeal cancer treated with radiotherapy is reported. The approach to managing such an aneurysm is discussed.

[Auditory brainstem implantation in patient with bilateral acoustic neuromas].

OBJECTIVE: To restore auditory sensation for patient suffering loss of hearing due to bilateral acoustic neuromas. METHOD: One patient of bilateral acoustic neuromas received auditory brainstem implant (ABI) at the same surgery for resection of the second tumor. The retrosigmoid approach was used for resection of the tumor and to exposure the lateral recess of the fourth ventricle for placement of ABI electrode array. Intraoperative 7th and 9th nerves monitoring and electrically evoked auditory brainstem responses (EABR) were recorded to localize the placement of ABI electrode array. RESULT: Initial ABI switch-on was performed eight weeks after the surgery under close monitoring of vital signs. Auditory sensation was perceived on stimulation of all channels. CONCLUSION: The multichannel ABI could effectively restore auditory sensation for patient deafened by bilateral acoustic neuromas. The accurate location of the cochlear complex during surgery was the critical factor for success of ABI.