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Systemic application of human mesenchymal stem cells (hMSCs) may be another effective tool for stem cell supply to the inner ear.Most researchers have used local application to provide the inner ear with stem cells. In spite of their efficacy, these methods can potentially cause irreversible damage to the inner ear. A homing phenomenon of systemically administered MSCs to the ischemic myocardium and brain was recently reported. Moreover, hMSCs have several advantages over conventional neural or embryonic stem cells. Thus we hypothesized that intense noise or ototoxic injury to the cochlea could induce the homing of hMSCs.We harvested hMSCs from bone marrow of the iliac crest of five normal individuals. Then hMSCs at a dose of 4 × 10(6) cells were given via intravenous injection of cell suspension into rats with cochleae damaged by noise or ototoxic drugs. Histological analysis was undertaken 30 days later.Systemically delivered hMSCs were usually largely entrapped in the lungs. However, we documented the homing of some hMSCs to the cochlea with degenerated inner hair cells. The recruitment of hMSCs was limited to the spiral ganglion area only. The migration of donor cells into the cochlea was accompanied by the expression of brain-derived neurotrophic factor (BDNF).

Mean incudostapedial joint (ISJ) angulation of atretic ears was statistically wider than ISJ angulation of non-atretic ears. Postoperative hearing results in the narrow tympanoplasty type II (T2) subgroup were better than those in the wide T2 subgroup. In cases of abnormally wide ISJ angulation, we recommend that partial ossicular reconstruction (POR) be used as a surgical means of achieving hearing improvement.To report the results of ISJ angulation in patients with congenital aural atresia and its effects on postoperative hearing improvement.Patients undergoing canaloplasty with T2 (149 ears) and canaloplasty with POR (32 ears) were enrolled. The T2 group was dichotomized according to an ISJ cut-off of an angle of 120° into the 'narrow' T2 and 'wide' T2 subgroups. The pre- and postoperative air-bone gap (ABG) and ABG change were analyzed.Mean ISJ angulation of non-atretic ears was 93.06 ± 13.21° and that of atretic ears in the T2 group was 118.39 ± 19.60° (p0.001). Mean short- and long-term postoperative ABGs were better in the narrow T2 subgroup than in the wide T2 subgroup (p = 0.01 and 0.03, respectively). The short-term postoperative ABG and ABG change in the POR showed superior results to those of the wide T2 subgroup (p0.001 and 0.041, respectively).

Benefits of the use of anteriorly and inferiorly based periosteal flaps (AIPFs) in congenital aural atresia (CAA) patients was found to be effective at reducing canal stenosis (CS) occurrence by long term F/U. However, in terms of minimizing CS, in addition to recruitment of AIPFs, considerations of patient factors, such as degree of microtia and age are mandatory.AIPF during canaloplasty were evaluated with a specific focus on whether this technique can offset the negative effects of several risk factors for postoperative CS after CAA surgery.The authors undertook a retrospective review of the medical records of 164 congenital aural atresia patients (190 ears) who had undergone surgery at Seoul National University Hospital. Median follow up period was 54 months. The anterior approach surgical method with and without the use of AIPFs were utilized in 111 and 79 ears respectively. Comparison of the influences of several factors on CS occurrence was undertaken by statistical analyses to evaluate whether this AIPFs technique can counterbalance the negative effect of patient factors in postoperative CS.Those with a younger age (12 yrs), moderate to severe microtia (grade II, III), or those in whom AIPF was not used in surgery (non AIPF group) were found to show statistically significant higher frequency of CS(+). Nevertheless, the positive effect of AIPF was not able to completely counterbalance the effects of negative patient factors on CS development. A protocol compatible with the results of this study that minimizes CS is presented in the discussion.

To propose management options for cochlear implantation in chronic otitis media based on our experiences.A retrospective review of 418 cochlear implantations performed by the 2 senior authors between November 1988 and February 2004 was conducted. Nine patients who had chronic otitis media in the ear to be implanted were included. Of these, three showed active inflammation at presentation; the other six cases had undergone previous tympanomastoidectomy surgery and did not show active inflammation at presentation.Five patients with active inflammation or without an adequate soft tissue layer in the mastoid bowl underwent a two-stage procedure. Four cases who showed inactive inflammation and had an adequate tissue layer to protect the electrode array underwent a single-stage technique, although two of them showed dry tympanic membrane perforation. No local or intracranial inflammation recurred. The electrode was exposed in the mastoid bowl in one case, who was managed with revisional mastoid obliteration with soft tissue.Complete eradication of inflammation and the securing of a strong protective soft tissue layer over the electrode are prerequisites for cochlear implantation in ears with chronic otitis media.

We used the IL088 Otodynamic Analyzer system to study click-evoked otoacoustic emissions (CEOAEs) in 30 healthy guinea pigs. The animals were anesthetized and patterns of the CEOAEs were evaluated before manipution, after the tympanic bulla was opened, and after formation of a microfistula on the basal turn of the cochlea. The animals then were divided into three pressure loading groups (10, 20, and 30 cm H2O). CEOAEs were recorded with a capillary manometer at pretest, 5, 10, 20, 30, 45, and 60 min after perilymphatic pressure loading to the basal turn of cochlea, and 10 and 20 min after pressure unloading. As perilymphatic pressure increased, all three pressure groups showed maximum decreases in both echo response and reproducibility 5 min after pressure loading. In the 10 cm H2O pressure group, emissions recovered 10 min after pressure loading, and this tendency continued. However, in the 20 and 30 cm H2O pressure groups, no recovery of emissions was seen throughout the 60 min observation period, except for emissions after pressure unloading. The results suggest that the echo response and reproducibility may be sensitive indicators of cochlear function and perilymphatic pressure regulation capacity.

Conclusion: The transcanal approach could be an effective and time-saving method for selected cochlear implantation (CI) candidates. Objective: This study was designed to introduce the method of CI via the transcanal approach used in patients with abnormal temporal bone structure or chronic otitis media (COM). Methods: The medical records of six patients who underwent CI via the transcanal approach were reviewed retrospectively. The electrode was inserted through the external auditory canal (EAC) after tympanomeatal flap elevation and cochleostomy. Results: Three patients had a history of inactive COM. In the remaining patients, cochleostomy via the transmastoid approach was difficult due to aberrant anatomic structures such as vascular anomaly, narrow aditus, and anteriorly displaced sigmoid sinus. All patients underwent CI via the transcanal approach successfully. There was no serious complication postoperatively.

In patients with cochleovestibular malformations, surgeons should always consider the possibility of an aberrant course or shape of the facial nerve (FN). In our series, the majority of cases could be successfully implanted without major complications through careful handling of the FN and ossicles.To assess the frequency, type, and surgical implications of FN aberrations encountered during cochlear implantation (CI).Medical records and radiologic findings of 972 patients who underwent CI from 1988 to 2009 were reviewed retrospectively. Radiologic and intraoperative findings demonstrating malformations of the FN, ossicles, and inner ear were evaluated. Intraoperative events and postoperative FN outcome were reviewed.Seven patients (0.7%) had an aberrant course or shape of the FN during CI. All these patients were pediatric. Four showed abnormal anterior or inferior location of the vertical segment, two had a bifurcated horizontal or vertical segment, and one had an inferiorly located horizontal segment. All seven patients displayed combined malformations of the cochlea and had malformed or missing ossicles. CIs were successfully performed via the facial recess approach and cochleostomy. There was no postoperative FN paralysis except in one case with immediate iatrogenic FN paralysis that recovered completely 1 month after FN decompression.

Functional changes of mitochondrial respiratory chain (MRC) and hearing threshold shifts were observed after noise exposure and the pattern was different depending on the extent of the noise damage.The aim of this study was to reveal any functional changes of the MRC enzyme in outer hair cells after noise damage.Sprague-Dawley rats were used and divided into three groups including normal control group and noise exposure for 1 h and 5 h. White band noise was used with 120 dB SPL. We measured hearing threshold and activity of succinate dehydrogenase (SDH) before noise exposure, and immediately and 1, 3, 7, and 14 days after noise exposure in each group. Immunostaining using monoclonal anti-MRC complex V subunit α was performed. Transmission electron microscopy (TEM) was carried out.The hearing threshold level changed depending on the exposure time in both the noise-exposed groups. In the 1 h group, hearing was improved after 1 day, and in the 5 h group, hearing was measured after 7 days. Changes in SDH activity were observed at the third day in the 1 h group and at the seventh day in the 5 h group. The expression level of MRC complex V was increased after noise exposure. TEM showed mitochondrial damage.

Claudius' cells absorb Na(+) through the amiloride-sensitive epithelial sodium channel (ENaC). Transepithelial ion transport through ENaC and possibly a Cl(-) secretory pathway is regulated by P2Y purinergic signaling.The purpose of this study was to investigate ion transport in Claudius' cells and its purinergic regulation.Young adult Sprague-Dawley rats and gerbils were studied. The Claudius' cell layer on the basilar membrane was dissected from the basal turn of the cochlea. A voltage-sensitive vibrating probe was used to measure transepithelial short circuit current (I(sc) ). The baseline I(sc) of Claudius' cells was measured in the perilymph-like control solution and the change of I(sc) after application of amiloride (10 μM) or uridine triphosphate (UTP, 100 μM).A negative baseline I(sc) was observed in the control solution (-12.50 ± 3.95 μA/cm(2), n = 8) and the addition of amiloride resulted in a decrease of I(sc) by 75.8%. The application of UTP, an agonist for P2Y purinergic receptors, led to a partial inhibition of I(sc) (by 38.2 ± 3.2%, n = 5), and subsequent addition of amiloride abolished the remaining I(sc).

In cases of petrous apex (PA) cholesteatoma, radical removal should be prioritized over an unreasonable sparing of hearing or facial symmetry. Nevertheless, for patients with serviceable hearing and spared inner ear structures, conservative approaches may be applicable. Restoration of facial nerve (FN) function is achievable by reanimation procedures.To analyze clinical manifestations, surgical techniques, and postoperative functional results of PA cholesteatoma.From 1987 to 2010, 13 cases of PA cholesteatoma underwent operations. Clinical, audiological, and radiological findings, surgical approach, and postoperative functional outcomes were analyzed retrospectively.The most common symptoms were hearing loss and FN paralysis. All PA cholesteatomas extended to the middle ear; 10 (76.9%) through the anterior-superior route, whereas the other 3 (23.1%) were through the posterior-superior route. In 10 patients, labyrinthectomy was inevitable because of inner ear invasion. However, three limited cholesteatomas were removable via the middle cranial fossa or transmastoid approach without changing the bone-conduction threshold. Among six cases with FN paralysis, one underwent interposition graft, two FN decompression, and the others hypoglossal-FN anastomosis. One FN decompression case recovered to House-Brackmann grade I, and all other reanimation cases finally presented with grade IV. There were no major complications or recurrences during the follow-up period.

Surgical treatment of fibrous dysplasia of the temporal bone (TBFD) revealed relatively good outcomes. Also, active surgical intervention is necessary to prevent the formation of secondary cholesteatoma or other complications. In particular, FD involving the inner ear may require greater caution when deciding on the resection area and timing of surgery.The purpose of this study was to analyze clinical manifestations of TBFD and its surgical outcomes.Nine patients diagnosed with TBFD after surgery at three tertiary referral centers were included. Pre- and postoperative clinical, audiological, and radiological findings were analyzed retrospectively.Most patients (88.9%) showed FD involving the mastoid and adjacent area. Radiological patterns consisted of six pagetoid and three sclerotic forms; seven patients were monostotic, whereas two patients were polyostotic. Canalplasty (CP) was performed in six cases and intact canal wall mastoidectomy was performed in three of them; hearing gain was achieved in five and one patient maintained preoperative normal hearing. Two patients underwent revision CP and showed no recurrence. In addition, one case had secondary cholesteatoma formed by an obstruction of the external auditory canal; another with a fast-growing cystic mass in the petrous bone underwent transmastoid labyrinthectomy and had no recurrence for 11 months.

Conclusion Cochlear implantation (CI) remains a safe procedure with a low complication rate. Nevertheless, advances in surgical techniques and the optimization of treatment modalities would further reduce complications. Objective To assess the complications of CI and describe the management of each complication encountered at our hospital. Patients and methods This study involved 720 patients that underwent implantation from November 1988 through April 2007. Mean age at implantation was 13.6 years (range 12 months to 83 years). Patients were followed up regularly with a mean follow-up of 42 months (range 4-81 months). Results No death was attributed to device implantation. Major complications included: device failure in 12 patients, misplaced electrodes in 4, hematoma in 3, flap necrosis in 3, magnet displacement in 2, facial nerve twitching in 2, electrode exposure in 2, external auditory canal keratoma in 1, immediate facial nerve paralysis in 1, and skin flap irritation due to the suture material in 1. The overall major complication rate was 4.2% (30/720), and there were 37 minor complications (5.1%), which were resolved by conservative treatment or minor intervention. Minor complications included temporary vertigo in 17 patients, facial twitching in 11, hematoma in 4, subcutaneous emphysema in 3, and temporary facial nerve paralysis in 2.

To evaluate the long-term speech perception of cochlear implantees and to compare the developing auditory performance patterns of prelingual children and postlingual deaf adults.Twenty-nine prelingually deaf children and 17 postlingually deaf adults who had been followed up for 4 years were included in the study. Speech perception ability was assessed by means of vowel and consonant confusion tests and the Korean version of the Central Institute of Deafness (K-CID) test (performed without visual cues). The test results were analyzed at 3 and 6 months after implantation and then annually.In the prelingually deaf children, the average results continuously improved over the 4-year period. In the postlingually deaf adults, the average results did not improve further after the first 2 years. Individuals with5 years of deafness had a faster rate of recovery of speech perception than those who had been deaf for5 years. The K-CID scores were negatively correlated with age at implantation for the prelingually deaf group and with the duration of deafness in the postlingually deaf group. Children fitted with implants at a younger age showed better speech perception ability than those fitted with implants at an older age. Interestingly, prelingually deaf children aged 5-7 years at implantation showed the widest variation in individual outcomes. Amongst this group of children with highly variable outcomes, the metabolic status of brain cortices determined by means of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was available for three patients. The individual with the widest hypometabolic area had the best speech perception ability.The extent of hypometabolism as assessed by FDG-PET seemed to be one of the major factors predicting the outcome of cochlear implantation.

Cisplatin ototoxicity is known to involve mainly the organ of Corti. Outer hair cells (OHCs). especially in the basal turn, are preferentially involved. One possible mechanism of ototoxicity might be alteration of the antioxidant system causing an increase in free radicals. It has been demonstrated that heat shock proteins (HSPs), which are believed to protect cells by dissolving and refolding misfolded or denatured protein are induced by various form of stress. HSP is also demonstrated to be induced by free radicals. The purpose of this study was to evaluate HSP 72 induction in cochlea following cisplatin injection in the animal model. Sprague-Dawley (SD) rats were injected intraperitoneally with normal saline as control or cisplatin at a dose of 5, 10 or 20 mg/kg. Cochleae were harvested 1, 3, 6 and 12 h after injection and compared with those of controls. Immunocytochemical study with surface preparation and Western blotting were performed to investigate the expression of HSP 72. Auditory brainstem response (ABR) was also recorded to assess functional change according to the dosage of cisplatin and duration after injection. In the 5 and 10 mg/kg groups, immunostaining for HSP 72 in the OHCs reached a plateau level at 3 h, which was maintained until 12 h after injection. The amount of immunoreactive OHCs in the 20 mg/kg group was smaller than those in 5 and 10 mg/kg groups and declined after 6 h. The bands for HSP 72 became less intense as the cisplatin dosage increased from 5 to 10 and 20 mg/kg in Western blotting. The change in ABR threshold was small in the 5 and 10 mg/kg groups and a marked change in threshold was observed in the 20 mg/kg group. Detection of HSP 72 after cisplatin injection could confirm the OHCs as one of the major injured cells in the cochlea. With a lethal dosage of cisplatin (20 mg/kg), HSP 72 expression was less prominent and declined after 6 h.