Surgical treatment of otosclerosis using a unique stapes prosthesis without a hook.

BACKGROUND: During stapes surgery, the Teflon wire piston prosthesis is prone to postoperative 'slips' and subsequent necrosis and fracture of the long process of the incus. AIMS/OBJECTIVE: We invented and used a novel cup-shaped apatite prosthesis to reduce the incidence of necrosis of the long process of the incus and analysed the postoperative results. MATERIAL AND METHODS: Thirty-one ears in 25 patients with otosclerosis who underwent stapes surgery with our apatite prosthesis were evaluated. RESULTS: The air conduction improved by 24.0 dB (the average) from pre- to post-operation. Additionally, 84.8% of patients achieved an air-bone gap of ≤10 dB for the 4-frequency measurements (p < .01). CONCLUSIONS: Our findings indicate that our new prosthesis was associated with a good postoperative prognosis in patients with otosclerosis. SIGNIFICANCE: Our unique prosthesis yielded good outcomes for the treatment of otosclerosis even in the short term.

Extended middle cranial fossa approach for vestibular schwannoma: technical note and surgical results of 896 operations.

From 1976 to 2006, 896 vestibular schwannomas were operated on using an extended middle cranial fossa approach. With this approach, the operative field can be extended according to tumor size and the facial and cochlear nerves can be preserved more easily with cooperation between the neurosurgeon and ENT surgeon. The mortality rate among 896 vestibular schwannoma patients was 0.3%. In the 760 initially operated vestibular schwannomas with total removal of the tumor, facial nerves were anatomically preserved in 715 or 94.1% of the cases. In 61.0% of 270 cases in which hearing preservation was attempted, hearing was preserved, and in 46.7% of those 270 cases useful hearing was preserved postoperatively. However, in the last 10 years the useful hearing preservation rate of the 140 attempted cases was 53.6%. Most of the complications of this approach were cerebrospinal fluid leakage; by using fat tissue, fibrin glue and spinal drainage from 1992 to 2005, cerebrospinal fluid leakage occurred in 59 or 10.6% of 569 cases, with 13 or 2.3% being repaired surgically. Moreover, in the last 10 years, the surgical results have improved along with improved surgical experience, improved instruments and better monitoring methods.

Hearing improvement after tumor removal in a vestibular schwannoma patient with severe hearing loss.

We herein report on the hearing improvement obtained after tumor removal in a vestibular schwannoma patient with preoperative severe hearing loss and good otoacoustic emission. Hearing recovery after tumor removal is an uncommon occurrence. As a result, hearing preservation surgery is usually not performed for patients with severe hearing loss. However, patients with a good OAE seem to have a better chance to recover their hearing than those with a poor OAE, even if they have severe hearing loss. As a result, the cochlear function should be evaluated, especially regarding the OAE, before determining the indications for hearing preservation surgery.

The diagnostic significance of the 3D-reconstructed MRI in vestibular schwannoma surgery: prediction of tumor origin.

In hearing preservation surgery for the treatment of vestibular schwannoma (VS), one of the important factors is the determination of the origin of VS. In this study, we investigated the diagnostic significance of using an MRI obtained by the three-dimensional Fourier transform fast spin-echo technique (3D-reconstructed MRI) in order to determine the origin of VS. The subjects consisted of 20 patients with mainly intra-canalicular sized VS who underwent tumor removal at our hospital. The origin of VS was determined from the 3D-reconstructed MRI findings and the results of the caloric test. These findings were then compared with the surgical findings. In 15 out of 20 patients, the MRI findings closely corresponded to the surgical ones, while the origin of VS hardly could be detected when a tumor filled up to the fundus acoustics on the MRI findings of the axial sections. On the other hand, 6 out of 15 patients (40%) whose tumor originated from the inferior vestibular nerve showed canal paresis. In conclusion, 3D-reconstructed MRI is considered to be helpful in obtaining more precise information regarding the origin of VS compared to the caloric test.

The glutamate receptor agonist, AMPA, induces acetylcholine release in guinea pig cochlea; a microdialysis study.

Acetylcholine (Ach) has been considered a major neurotransmitter in the inner ear efferent nerve endings. A bioassay analysis has shown that the electrical stimulation of the crossed olivocochlear bundle increased the Ach-like activity in the perilymph. Applying in vivo microdialysis techniques and high-performance liquid chromatography to the perilymph, the change of Ach level was thus measured before and after alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA), a glutamate receptor agonist, was added to the perfusate. Ach was only detectable when the perfusate contained an acetylcholinesterase inhibitor. The level of Ach increased 2-3-fold immediately after AMPA was administered. Our data suggest that the afferent stimulation, such as the administration of AMPA, may therefore induce the release of Ach from the efferent nerve endings.

Effects of neuropeptide Y on cochlear blood flow in guinea pigs.

The aim of this study was to clarify the effects of neuropeptide Y (NPY) on cochlear blood flow (CBF) in pigmented guinea pigs. NPY was administered with or without noradrenaline (NA) by systemic perfusion or perilymphatic local perfusion, and CBF was measured using a laser Doppler flowmeter. The systemic and perilymphatic administrations of NPY with NA induced greater prolongation of the increase in and recovery of CBF than the administration of NA or NPY alone. Continuous reduction in CBF induced by NPY may play an important role in the pathogenesis of stress-induced sensorineural hearing losses, such as sudden deafness.

Skeletal muscle regeneration after insulin-like growth factor I gene transfer by recombinant Sendai virus vector.

We scrutinized the applicability and efficacy of Sendai virus (SeV) vectors expressing either LacZ or human insulin-like growth factor-I (hIGF-I) in gene transfer into skeletal muscle. Seven days after the intramuscular injection of LacZ/SeV X-gal labeled myofibers were demonstrated in rat anterior tibialis muscle with/without bupivacaine treatment and the transgene expression persisted up to 1 month after injection. Recombinant hIGF-I was detected as a major protein species in culture supernatants of a neonatal rat myoblast cell line L6 and thus induced the cells to undergo myogenetic differentiation. The introduction of hIGF-I/SeV into the muscle showed a significant increase in regenerating and split myofibers which were indicative of hypertrophy, and also an increase in the total number of myofibers, in comparison to that seen in the LacZ/SeV-treated control muscle. These results demonstrate that SeV achieves high-level transgene expression in skeletal muscle, and that hIGF-I gene transfer using SeV vector may therefore have great potential in the treatment of neuromuscular disorders.

The learning curve in post-operative hearing results in vestibular schwannoma surgery.

PURPOSE: We chronologically investigated whether the hearing preservation (HP) rate improved or not in vestibular schwannoma (VS) surgery. SUBJECTS AND METHODS: HP surgery has been attempted in 127 VS patients with pre-operative class A and B hearing from 1976 to 1999. The HP rate was chronologically compared with hearing level and tumor size. RESULTS: The preservation rate of pre-operative class A hearing which was preserved post-operatively as class A has recently been increasing especially in patients with an intracanalicular (IC) tumor. This rate was improved to 67% from 1995, although this was 33% from 1989 to 1994. However, the preservation rate of pre-operative class B in patients with an IC tumor and that of pre-operative class A hearing which was preserved as class A in patients with a larger tumor extending into the posterior fossa, have not improved over the last 10 years. CONCLUSION: These results indicate that the improvement of the HP rate is mainly due to the increased number of patients with an IC tumor with class A pre-operative hearing. In patients with a tumor of 4-20 mm in size, especially in those showing pre-operative class B hearing, there may be histologically some limitations such as gliosis in the cochlear nerve in the preservation rate of good quality (class A or B) of hearing.

Manifest Anxiety Scale for evaluation of effects of granisetron in chemotherapy with CDDP and 5FU for head and neck cancer.

The level of anxiety was examined before treatment by means of the Manifest Anxiety Scale (MAS) in 41 patients with squamous cell carcinoma of the head and neck. They received 5 days of neoadjuvant chemotherapy with cisplatin (CDDP) and 5-fluorouracil (5FU). Granisetron (KYT) was administered daily from day 1 to day 5. Nausea, vomiting, appetite, and well-being were assessed during and after chemotherapy. The relation between the effects of KYT and anxiety was studied. Seventeen patients were proven to have anxiety and were compared with the other 24 patients. In patients with anxiety, the percentage well-being was significantly lower on days 1 and 2 (P=0.008, 0.001). The rate of freedom from nausea was significantly lower from day 4 to day 9 for anxiety patients (P=0.010-0.050). The percentage of anxiety patients without loss of appetite was significantly lower from day 6 to 9 (p=0.001-0.020). The rate of freedom from vomiting was significantly lower on days 4, 5 and 7 for anxiety patients (P=0.024, 0.024, 0.014). The results indicate that the effect of KYT was significantly lower from day 3 to day 7 for anxiety patients (P=0.008-0.045). The anxiety group had significantly poorer well-being at the beginning of chemotherapy, and were not responsive to KYT in the delayed phase. Our results prove that anxiety patients show delayed emesis, and the administration of KYT is considered insufficient. It may be important to co-administer a tranquilizer to any patient who exhibit anxiety as defined by the MAS, in order to reduce delayed emesis.

Heterogeneity of phospholipase C in the cochlea of the guinea pig.

In the present study, we investigated the presence of phosphatidylinositol-specific phospholipase C (PLC) isoforms in the cochlea of the guinea pig using Western blot analysis and immunocytochemistry. By Western blotting, PLCbeta1 and delta1 were expressed in the cochlear sensory epithelia (CSE) and PLCbeta1, gamma1 and delta1 were expressed in the cochlear lateral wall. By immunocytochemistry of the CSE, PLCbeta1-like immunoreactivity was mainly expressed in the outer hair cells (OHCs), but not in the inner hair cells (IHCs). PLCgamma1 and delta1 were expressed neither in the OHCs nor in the IHCs. In the cochlear lateral wall, PLCbeta1, delta1 and gamma1 were expressed in the stria vascularis and the spiral ligament. In addition, PLCbeta1, delta1 and gamma1 were also present in type I spiral ganglion cells. Based on these results, we discussed the function of these PLC isoforms in the cochlea.

Mechanisms of photoinduced cochlear ischemia in the guinea pig.

An experimental model of cochlear ischemia using the photosensitization reaction of rose bengal (RB) is reported. Ischemia was induced by the systemic administration of RB solution and localized irradiation of the cochlea with a green light of specific wavelength for RB activation. After the RB solution was administered, the cochlear blood flow was temporarily increased and then decreased, and the latency of wave I of the auditory brainstem response increased and the amplitude of wave I decreased after RB injection and finally wave I disappeared completely. A histological study revealed thrombus formation in the vessels of the irradiated cochlea not only in the stria vascularis and the spiral ligament, but also in the modiolus. L-Histidine, a scavenger of singlet oxygen (1O2) and hydroxyl radical (.OH), significantly prolonged cochlear dysfunction, but D-mannitol, a specific scavenger of.OH did not, suggesting that 1O2 has an important role in this reaction.

[Pathogenesis mechanism in ear fullness in otosclerosis].

To clarify the mechanism underlying ear fullness in otosclerosis, we studied the relationship between clinical features and examinations. Subjects were 116 otosclerosis patients (140 ears). The presence or absence of ear fullness was judged from a questionnaire in initial diagnosis or a chart description. Ear fullness was observed in 44 ears (31%) and absent in 96. The averaged air and bone conduction hearing levels (500 Hz-4 k Hz) in initial diagnosis were significantly lower in the group with ear fullness. The difference in averaged hearing was mainly apparent at 2 k Hz and 4 k Hz. The difference in hearing at lower frequencies (125 Hz, 250 Hz, and 500 Hz) and higher frequencies (2 k Hz, 4 k Hz, and 8 k Hz) was significantly larger in the group of ear fullness. From these results, we postulated that ear fullness in otosclerosis is caused by fixation of the stapes. The psychoacoustic abnormal sensation caused by lower input of lower-frequency sound or incomplete fixation of the stapes may cause ear fullness. Further study is needed to clarify the pathogenesis of ear fullness in different ear pathologies.

[Evaluation of hearing recovery and a grading system established by the Research Group on Sudden Deafness of the Japanese Ministry of Health and Welfare].

A grading system for sudden deafness has been established by the Research Group on Sudden Deafness of the Japanese Ministry of Health and Welfare. According to this grading system, sudden deafness cases are classified according to the initial hearing level and the vestibular symptoms. Few clinical analyses of sudden deafness cases have been made using this grading system. In this study, 263 sudden deafness cases were classified into 6 groups based on the grading system. All of the cases presented with an initial hearing level of more than 40 dB and underwent treatment within 1 week of the onset of symptoms. The relationship between the grading system and hearing recovery is discussed. Fixed hearing levels with a good prognosis were grades 2b, 2a, 3b, 3a, 4b and 4a. To quantitatively evaluate hearing recovery, the average hearing recovery rate and the percentage of the complete recovery cases were analyzed for each group. Average hearing recovery was ranked into five levels, regardless of the evaluation method. Grades 2b and 3b were the best, and grade 4a was the worst. After grades 2b and 3b, grade 2a was the second best, grade 3a was the third, and grade 4b was the fourth. The cases included in grades 2 and 3 were more strongly effected by whether the cases had vestibular symptoms or not than by their initial hearing levels. When grade 4 cases were classified by their initial hearing level, a large difference existed among grade 4a cases with regard to whether they presented with an initial hearing level of under or more than 100 dB. The hearing recovery of grade 4a cases with an initial hearing level of less than 100 dB was almost the same as that of grade 3a. However, the hearing recovery of grade 4b cases varied only slightly. Consequently, some ranges of initial hearing level exhibited similar degrees of hearing recovery. In cases without vestibular symptoms, the range of initial hearing levels was 40-89 dB. These cases had a 60% chance of complete recovery, and the hearing recovery rate was 80% on average. In cases with vestibular symptoms, the range of initial hearing levels was 60-99 dB. These cases had a 40% possibility of complete recovery, with an average hearing recovery rate of 60%. After comparing the initial grades and the final grades using the same grading system, the majority of grade 2 and 3 cases attained a grade 1 fixed hearing level. However, most grade 4 cases had a grade 3 fixed hearing level.

Quality of life of vestibular schwannoma patients after surgery.

The quality of life of vestibular schwannoma (VS) patients after surgery was investigated. The subjects consisted of 236 unilateral VS patients who underwent tumor removal between 1990 and 1997. A questionnaire was sent to all patients regarding their hearing, tinnitus, dizziness and the changes in their daily life after surgery; 176 out of 204 patients (86%) who received the questionnaire completed and returned it. The answers were compared with recent data reported in other clinical studies. Ninety percent of the patients with postoperative class A hearing were satisfied with their hearing. However, only 30% of patients with postoperative class B hearing were satisfied. Tinnitus worsened after surgery more often in patients who underwent a labyrinthectomy than in those who did not. Dizziness improved after surgery in the majority of VS patients. However, 30% of patients had difficulty driving a car and 50% of patients could not enjoy activities such as playing sport after surgery.

Analysis of vocal fold vibration by x-ray stroboscopy with multiple markers.

OBJECTIVE: To derive a more precise description of vocal fold vibration, experimental phonation of excised canine larynxes was studied. STUDY DESIGN AND SETTING: Multiple X-ray-positive markers were inserted, and their vibratory movement was observed with x-ray stroboscopy with change of pitch and intensity. A histologic study was also carried out. RESULT: Regular waves were observed just above the lowest point of the lamina propria of the mucous membrane, which shifted upward at high pitch, but downward in high intensity. CONCLUSIONS: The starting point of the mucosal wave was confirmed on the lower surface of the vocal fold, histologically just above the lowest point of the lamina propria of the mucous membrane and shifted upward at high pitch, but downward in high intensity. SIGNIFICANCE: This is the first study investigating the starting point of mucosal wave in vocal fold vibration in a frontal plane using x-ray stroboscopy, providing the evidence for the body-cover theory.

Effects of changes in stimulus level on phases of distortion product otoacoustic emissions.

Effect of changes in stimulus levels of both lower (f(1)) and higher (f(2)) stimulus tones on phases of 2f(1)-f(2) component of the distortion product otoacoustic emission (DPOAE) was examined in five normal hearing adults. The f(2) was fixed at 4004 Hz in all of the measurements, and the stimulus frequency ratio (f(2)/f(1)) was varied from 1.15 to 1.3. Change of the level of lower stimulus tone (L(1)) and the level of higher stimulus tone (L(2)) showed different effects on the DPOAE phases. The phase lags increased with increasing L(1), when f(2)/f(1) was above 1.22, whereas the phase gains increased with increasing L(1), when f(2)/f(1) was below 1.22. On the other hand, the difference in L(2) minimally affected DPOAE phase at most f(1)s. The previous studies about basilar membrane vibration revealed that phase lags increase with increasing stimulus level, when the stimulus frequency is below the best frequency, while phase gains increase with increasing stimulus level, when the stimulus frequency is above the best frequency, and the effect of phase change in stimulus level diminished, when the stimulus frequency was far above the best frequency. Based on the comparison between the results of the present study and the previous findings of others concerning basilar membrane vibration, the DPOAE generation site is assumed to be located at apical of the peak of the f(2) traveling wave.

Connexin 26 distribution in gap junctions between melanocytes in the human vestibular dark cell area.

We have previously demonstrated the presence of gap junctions between melanocytes in the human vestibular organ and have speculated that melanocytes function in maintaining the homeostasis of the microenvironment of the inner ear. The purpose of the present study was to characterize the expression and ultrastructural localization of connexin (Cx) protein in melanocytes of the human vestibular organs. Surgical material was obtained from patients operated on for vestibular schwannoma and was processed for light microscopy, confocal laser scanning microscopy, conventional TEM, and immuno TEM. The specimens were labeled with anti-Cx26, Cx32, and Cx43 antibodies and examined by light microscopy. Specimens were also labeled with anti-Cx26 antibody and examined by laser microscopy and immuno-TEM methods. The specimens examined in this study were mainly dark cell areas from the human vestibular organ, whose epithelial and subepithelial layers are rich in melanocytes. Light-microscopic immunohistochemical studies showed positive labeling for Cx26 protein between subepithelial melanocytes, and Cx32 was also detected. Use of anti-Cx26 antibody and confocal laser scanning microscopy revealed high levels of Cx26 around the subepithelial melanocytes. Post-embedding immuno-gold transmission electron microscopy showed significant aggregation of gold particles (33.97 +/- 8.01% of total gold particles) around the gap junctions of the subepithelial melanocytes. The results of this study indicated that melanocytes are connected through gap junctions that mainly contain Cx26. This suggested that the melanocytes in the human vestibular organ may play a role in transporting material between the endolymph and perilymph.

Perilymph fistula--45 case analysis.

PURPOSE OF THE STUDY: Though perilymph fistula (PLF) is not a rare disease, preoperative diagnosis still remains to be established. Some new diagnostic methods are challenging, but there is still no established diagnostic method except exploratory tympanotomy that verifies the occurrence of leakage. Early diagnosis of PLF is fully depending on history taking and some clinical examinations. To know the clinical features of PLF is one of the greatest helps to make both earlier and accurate diagnosis. In spite of some innovations in clinical examinations classic diagnostic procedure is thought to be still reliable. PROCEDURES: We investigated the clinical symptoms, basic tests results and therapeutic results in patients with PLF. RESULTS: From 1983 to 1998 PLF was identified in 44 patients (45 ears) with exploratory tympanotomies in our hospital. With respect to clinical history the predisposing factors such as blowing the nose, lifting heavy goods, and landing in an airplane were found in almost half of the patients, while the rest of them had no clear inducing factors. Their major symptoms included hearing loss (93%), vertigo and dizziness (91%), tinnitus (76%), and aural fullness (31%). The patients who have a clear predisposing factor tended to make diagnosis easily; on the other hand the rest of the patients who do not have clear etiology had some diagnostic difficulty. Subjective positive fistula signs were observed in 71% of patients. Vestibular symptoms improved in 80% of patients after closure of PLF. CONCLUSIONS: These results suggest that the variety of clinical manifestation make diagnosis more difficult. At the moment meticulous clinical history taking and close follow-up applying repeating fistula tests are the most important for not only earlier but also accurate diagnosis.

Study of movements of individual structures of the larynx during swallowing.

OBJECTIVE: The purpose of this study was to reveal movements of individual structures of the larynx during swallowing. METHODS: Subjects were 7 healthy adults, aged 24 to 32 years (average 27 years), who had no organic or functional disease of the pharynx and larynx and 2 adults with unilateral recurrent nerve palsy, aged 49 and 60 years, respectively. We used the Toshiba IIDR system, which is composed of an X-ray TV system and a digital image managing circuit. One-fifth diluted Omnipark 300 was used as contrast medium (lohexol), with 15 cc for each swallow. The mask image for subtraction was designated as the frame before laryngeal elevation during swallowing for subtraction. We obtained the images for observation and analysis after subtracting the mask image from continuously obtained images. These images were captured into a personal computer at 30 frames per s and thereafter frame-by-frame observation and analysis were performed by means of NIH image 1.56. RESULTS: We observed that the vocal folds underwent a series of movements during swallowing. (1) They adduct slowly and do not ascend; (2) then begin to ascend and continue adducting; whereby (3) they abduct for a moment while ascending. (4) Again, they adduct and achieve closure. (5) While maintaining closure, vocal folds elevate further to reach their maximal elevation; and (6) begin to abduct rapidly while maintaining maximal elevation. Finally, (7) they begin to descend and undergo repeated irregular abduction and adduction while descending. In examining the relationship between closure and opening at levels of the vocal fold and false vocal fold, we found that closure at the false vocal fold level precedes that at the vocal fold level and that opening at the vocal fold level precedes that at the level of the false vocal fold. CONCLUSION: Closure of the false vocal fold level appears important in the protection of the lower respiratory tract during swallowing.

Morphological evidence that impaired intraneural microcirculation is a possible mechanism of eighth nerve conduction block in acoustic neuromas.

In an attempt to better understand the mechanism of eighth nerve dysfunction in acoustic neuromas (vestibular schwannomas), we have morphologically examined microvessels and nerve fibers in the intracanalicular portion of eighth nerve specimens attached to these tumors. At the light microscopic level, microvessels were well preserved in all the specimens, even in the extremely flattened or markedly small nerve fascicles. However, the density of microvessels was quite variable in the different specimens, presumably as the result of different levels of compression by the tumors and the subsequent formation of a collateral microcirculation in each nerve. Focal areas of mild endoneurial fibrosis were found in 9 out of 22 specimens examined, but severe and widespread degeneration or demyelination was not found in any of the specimens. Ultrastructural studies frequently revealed mild to moderate abnormalities in myelin sheaths, and occasionally showed endothelial hyperplasia and hypertrophy in all the specimens. These findings are consistent with the slight to moderate reduction of endoneurial blood flow in the eighth nerves. The resultant ischemic condition in the eighth nerve may account for the eighth nerve conduction block in acoustic neuromas.