Faculty Bibliography

The contrast-enhanced computed tomographic (CT) scans of the temporal bone and brain in 18 patients with otologic disease and acquired immunodeficiency syndrome (AIDS) were retrospectively reviewed. Seven scans revealed middle ear and mastoid disease; three scans were consistent with central nervous system (CNS) pathology; and eight scans demonstrated no abnormalities. CT scanning was found useful in localizing otopathology and diagnosing CNS toxoplasmosis, aural polyps, osteomyelitis, mastoiditis, and middle ear effusion due to hypertrophic lymphoid tissue. The authors conclude that AIDS patients with sensorineural hearing loss should undergo contrast-enhanced brain CT scans to rule out CNS pathology; AIDS status does not alter criteria for CT scanning in patients with conductive hearing loss; and that images of the nasopharynx should be included on temporal bone CT scans of patients with conductive hearing loss in order to exclude eustachian tube obstruction by hypertrophic lymphoid tissue

Facial nerve paralysis associated with cerebellopontine angle surgery has been reported to range up to 26% in a recent series. Various methods of intraoperatively monitoring the facial nerve have been developed to reduce the incidence of facial paralysis. We report our experience with an intraoperative monitoring technique using intramuscular EMG electrodes to detect subclinical electrical responses that were amplified and made audible to the operating surgeon after gating stimulus artifacts. A 3.6% incidence of facial paralysis in 111 consecutive cases with this intraoperative monitoring method compared with 14.5% in 207 previously unmonitored cases indicates significant reduction of this complication in cerebellopontine angle surgery (p less than 0.001). Along with this reduction in facial paralysis, an increase in the percentage of partial facial paresis was observed in the monitored group (p less than 0.05). The percentage of those with intact facial function was similar in the monitored (82.0%) and unmonitored groups (78.3%)

Extrapulmonary infection with Pneumocystis carinii is rare and is usually associated with severe systemic illness. We report, in two patients, the histologic, ultrastructural, and monoclonal cell surface antibody identification of P carinii in otic polyps. Both patients had serum antibody to human immunodeficiency virus. These P carinii infections in the temporal bone are unusual in their location and in the apparent absence of associated pulmonary infection. This otologic presentation was the primary manifestation of the acquired immunodeficiency syndrome

For reinnervation of facial paralysis, the XII-VII nerve anastomosis provides tone and mass contraction but rarely allows selective muscle control. The efficacy of EMG rehabilitation was evaluated in 30 patients who had no coordinated control of facial muscles. EMG signals from bilateral homologous facial muscle sites were converted into computer-compatible waveform traces and displayed on a video monitor. This facilitated modification of neuromuscular responses using behavioral shaping techniques. A six-point Facial Nerve Grading Scale was introduced for hypoglossal-facial nerve anastomosis to assess the results of EMG rehabilitation. Rehabilitation lasted from 3 to 18 months. Ten patients (33%) achieved the highest possible grading (II) with symmetry and synchrony of function and spontaneity of expression; 17 (57%) reached grade III, which allowed voluntary control of eye and mouth function; 3 (10%) showed minimal gains. It is suggested that neural plasticity allows therapeutic manipulation of central facilitory and inhibitory mechanisms, and possible unmasking of neural connections between the ipsilateral VII and XII nerve motor nuclei which leads to improved facial function

Electromyographic (EMG) feedback has been proposed to enhance rehabilitation following hypoglossal-facial nerve anastomosis. Sixteen of 25 patients who underwent hypoglossal-facial nerve anastomosis with and without postoperative EMG rehabilitation were videotaped for evaluation of facial movement by four observers unaware of these patients' rehabilitation therapy. Using a House Facial Nerve Grading System and intragroup comparison, a trend discernible in this preliminary study indicates a chance for better facial function with EMG feedback rehabilitation

Injury to the facial nerve is of concern in surgery of cerebellopontine angle tumors. The crossed acoustic reflex provides a way to monitor the ipsilateral facial nerve with the auditory stimuli delivered to the contralateral side. Using the method of optimum digital filtering, it is possible to monitor the resulting brain stem facial evoked response (BFER) in real time. This paper presents preliminary experiences in more than 18 such operations monitored using this method. This preliminary study demonstrates a trend for a high (88.8%) correlation between BFER and postoperative facial nerve function. Identical latencies from simultaneous BFER and facial nerve recordings along with findings after facial nerve transection suggest that some portion of the complex BFER waveform derives from facial nerve depolarization

The signal-to-noise ratio of brainstem auditory evoked responses (BAER) can be greatly enhanced by use of optimal digital filtering before averaging. This permits accurate assessment of auditory nerve status every 5 to 10 seconds, making real-time intraoperative monitoring possible. The major advantages yielded by real-time monitoring--in our experience thus far--have been identification of potentially adverse functional consequences of apparently uneventful surgical maneuvers, reducing postoperative dysfunction, early indication of potential for improved clinical function, and potential identification and localization of neural tissue in the face of absent surgical landmarks. Examples of these advantages will be provided from case studies, and the possibility that real-time monitoring may improve ability to preserve hearing will be discussed

Lesions involving the petrous apex are rarely encountered in clinical practice. This directly affects the ability of the otolaryngologist to diagnose and effectively treat these lesions. Greater physician awareness and increased technologic capability are leading to more effective management of pathologic conditions involving this area of the temporal bone