Eigo Omi

Gait instability caused by vestibular disorders - analysis by tactile sensor.

OBJECTIVE To elucidate instability of gait performance in patients with vestibular lesions by the use of a tactile sensors placed under both feet. METHODS Gait analysis was conducted by the use of tactile sensors in 92 patients who had various types of vestibular lesions including vestibular neuritis (VN), acoustic neuroma (AN), and spinocerebellar degeneration (SCD). 26 healthy adults served as a control. Variables were coefficient of variation of stance, swing, and double support durations. Morphological analysis of foot pressure progression during stance was also performed. In addition, differences in each foots integrated foot pressure in a gait test were measured, especially in cases with unilateral vestibular lesions. All data was comparatively analyzed between each pathological group and control group. A comparative study between intact side foot and lesion side foot was performed in those unilateral vestibular disorder cases as well. RESULTS Those gait phase related variables were significantly greater in the pathologic group than in the control group, especially under gait with eyes closed. Morphological irregularity of foot pressure progression during stance was shown in cases with VN and SCD and was greatest in SCD cases. As for integrated foot pressure, in most cases with VN, it has become greater in the lesion side foot, suggesting that body center of gravity could shift toward the lesion side during gait. CONCLUSIONS Gait analysis by the use of tactile sensors could provide additional important information regarding vestibular patho-physiology in patients with vestibular system disorders. Accordingly, gait performance tests should also be taken into consideration as a vestibular function test for patients with vertigo.

Insulin-like growth factor 1 protects vestibular hair cells from aminoglycosides.

This study investigated the therapeutic potential of insulin-like growth factor-1 (IGF-1) for vestibular hair cells using explant cultures of mouse utricles. After incubation with the ototoxic drug gentamicin, explants from neonatal mouse utricles were cultured in medium containing IGF-1 at various concentrations. Histological evaluation revealed significant increases in the number of surviving hair cells cultured with IGF-1 at concentrations reflecting a clinical setting. Immunostaining for trio-binding protein and espin showed the maintenance of functional structures in hair bundles at the apex of surviving hair cells. An FM1-43 assay indicated the presence of mechanoelectrical transduction channels in surviving hair cells. These findings indicate that IGF-1 may protect the functionality of vestibular hair cells against drug-induced injury.

Small vestibular schwannomas can cause gait instability.

PURPOSE To confirm whether detailed gait analysis can detect gait instability in patients with small vestibular schwannoma (VS) with an apparently normal gait. METHODS Twenty-two patients (7 males, 15 females; 40-64 years old) with small VS and nine healthy age- and weight-matched controls were enrolled. Small VS was defined as the longest diameter less than 20mm from the porus acusticus internus on MRI with no brainstem compression. Each subject was asked to walk straight for a distance of 8m with tactile sensors attached to both feet, and repeat two trials with eyes open and closed. Gait variables of stance, swing, double support, stability, and average length of the trajectories of the center of force (TCOF) during stance were recorded and analyzed. RESULTS No significant differences in the stability of the TCOF were found during gaits with eyes open and closed between the two groups. No obvious changes in gait variables were recognized with eyes open between the two groups. However, under gait with eyes closed, the values of the coefficient of variation (CV) of the gait phase were significantly greater in stance and swing in the VS group than in the normal group. In addition, patients with canal paresis (CP) showed greater CV values in gait phase related parameters than those who without CP during gait with eyes closed. CONCLUSIONS Patients with small VS may have an apparently normal gait, but their vestibular deficit could be detected by proper use of gait analysis, especially with visual deprivation.

Giant Cell Tumor of the Temporal Bone Invading into the Pterygoid Muscle through the Temporomandibular Joint

We report a case of giant cell tumor of the temporal bone invading into the pterygoid muscle through the temporomandibular joint. The patient was a 43-year-old woman who developed left ear fullness 2 years earlier with a mass in the external auditory canal. Radiologic evaluation revealed extension into the infratemporal fossa and confirmed that the tumor was invading into pterygoid muscle. A middle cranial fossa approach along with tympanoplasty was used for total resection of the tumor. Once a tumor invades into muscle tissue, meticulous care is required to remove it because identification of tumor tissue becomes extremely difficult.

Outcome of different facial nerve reconstruction techniques.

INTRODUCTION There is no technique of facial nerve reconstruction that guarantees facial function recovery up to grade III. OBJECTIVE To evaluate the efficacy and safety of different facial nerve reconstruction techniques. METHODS Facial nerve reconstruction was performed in 22 patients (facial nerve interpositional graft in 11 patients and hypoglossal-facial nerve transfer in another 11 patients). All patients had facial function House-Brackmann (HB) grade VI, either caused by trauma or after resection of a tumor. All patients were submitted to a primary nerve reconstruction except 7 patients, where late reconstruction was performed two weeks to four months after the initial surgery. The follow-up period was at least two years. RESULTS For facial nerve interpositional graft technique, we achieved facial function HB grade III in eight patients and grade IV in three patients. Synkinesis was found in eight patients, and facial contracture with synkinesis was found in two patients. In regards to hypoglossal-facial nerve transfer using different modifications, we achieved facial function HB grade III in nine patients and grade IV in two patients. Facial contracture, synkinesis and tongue atrophy were found in three patients, and synkinesis was found in five patients. However, those who had primary direct facial-hypoglossal end-to-side anastomosis showed the best result without any neurological deficit. CONCLUSION Among various reanimation techniques, when indicated, direct end-to-side facial-hypoglossal anastomosis through epineural suturing is the most effective technique with excellent outcomes for facial reanimation and preservation of tongue movement, particularly when performed as a primary technique.

Large middle ear schwannoma of the Jacobson's nerve with intracranial extension

The patient is a 64-year-old woman who developed a sensation of right ear fullness and hearing loss in early November 2010. Physical examination revealed a painless reddish granular lesion filling in the right external auditory canal. Her right ear was deaf, and no facial palsy was noted. Computed tomography, magnetic resonance imaging and positron emission tomography revealed a middle ear mass extending to the external auditory canal with intracranial invasion causing temporal lobe retraction and inferiorly extending just anterior to the jugular bulb as well. A combination of transmastoid and middle cranial fossa approach along with anterior rerouting of the facial nerve was employed for a near-total removal of the tumor. Based upon the operative findings, it was deemed that the tumor could have arisen from the Jacobsons nerve.

Facial nerve neuroma in the geniculate ganglion extending into the internal auditory canal: A case report

Facial nerve schwannoma is a very rare benign tumor representing less than 1% of intrapetrous lesions. Our patient is a forty-one year old female who has suffered from recurrent right facial palsy for the last six years. She was first misdiagnosed as having Bells palsy and received corticosteroids which resulted in little improvement. She then had facial nerve decompression surgery which resulted in a partial improvement. Since then, she has suffered from recurrent attacks of facial palsy. Two years ago, she came to our hospital seeking further treatment options. The final diagnosis made by MRI was a possible facial nerve tumor. To obtain a better facial outcome, total tumor removal was performed through the middle cranial fossa approach along with facial-hypoglossal nerve end-to-side anastomosis through transmastoid approach. Her hearing was preserved, and she obtained a better facial outcome than that of her preoperative level. In conclusion, facial nerve schwannoma has the potential to be misdiagnosed as Bells palsy which might lead to a delay in diagnosis, and end-to-side neurorrhaphy may be an effective alternative in a selected case.