Efficacy and safety of a self-expandable retainer in endoscopic ear surgery.

PURPOSE: During endoscopic ear surgery (EES), it is important to maintain a clear view of the endoscopic camera to achieve a clean field. In this study, a self-expandable external auditory canal (EAC) retainer was developed to enable a more efficient and safer EES. This study aimed to evaluate the retainer's efficacy and safety in EES. METHODS: Among adult patients scheduled for endoscopic tympanoplasty, 50 participants were recruited. They were assigned to either the retainer or control group in a 1:1 ratio. The anatomical characteristics, number of endoscopic cleanings during surgery, surgeon's satisfaction, and other factors were evaluated. RESULTS: No differences were observed in the surgical direction, EAC size measured on preoperative temporal bone computed tomography scans, location and size of tympanic membrane perforation, or bleeding degree between the two groups. When comparing the surgical time, including retainer insertion and removal, the time was similar between groups (retainer group, 35 min; control group, 33.2 min). The frequency of endoscopic cleaning per minute was statistically significantly lower in the retainer group than in the control group (0.18 times per minute, p = 0.048). No side effects, including sensory abnormalities or allergic reactions, were reported in any patient who used the retainer. CONCLUSION: A reduction in unnecessary endoscopic cleaning during EES was observed while using the self-expandable retainer, leading to increased surgeon satisfaction and efficiency. Furthermore, as a safe method without side effects, the retainer could be widely used to various indications for EES beyond tympanoplasty.

Enhancing Si3N4 Selectivity over SiO2 in Low-RF Power NF3-O2 Reactive Ion Etching: The Effect of NO Surface Reaction.

Highly selective etching of silicon nitride (Si3N4) and silicon dioxide (SiO2) has received considerable attention from the semiconductor community owing to its precise patterning and cost efficiency. We investigated the etching selectivity of Si3N4 and SiO2 in an NF3/O2 radio-frequency glow discharge. The etch rate linearly depended on the source and bias powers, whereas the etch selectivity was affected by the power and ratio of the gas mixture. We found that the selectivity can be controlled by lowering the power with a suitable gas ratio, which affects the surface reaction during the etching process. X-ray photoelectron spectroscopy of the Si3N4 and QMS measurements support the effect of surface reaction on the selectivity change by surface oxidation and nitrogen reduction with the increasing flow of O2. We suggest that the creation of SiOxNy bonds on the surface by NO oxidation is the key mechanism to change the etch selectivity of Si3N4 over SiO2.

Cortical reorganization following auditory deprivation predicts cochlear implant performance in postlingually deaf adults.

Long-term hearing loss in postlingually deaf (PD) adults may lead to brain structural changes that affect the outcomes of cochlear implantation. We studied 94 PD patients who underwent cochlear implantation and 37 patients who were MRI-scanned within 2 weeks after the onset of sudden hearing loss and expected with minimal brain structural changes in relation to deafness. Compared with those with sudden hearing loss, we found lower gray matter (GM) probabilities in bilateral thalami, superior, middle, inferior temporal cortices as well as the central cortical regions corresponding to the movement and sensation of the lips, tongue, and larynx in the PD group. Among these brain areas, the GM in the middle temporal cortex showed negative correlation with disease duration, whereas the other areas displayed positive correlations. Left superior, middle temporal cortical, and bilateral thalamic GMs were the most accurate predictors of post-cochlear implantation word recognition scores (mean absolute error [MAE] = 10.1, r = .82), which was superior to clinical variables used (MAE: 12.1, p < .05). Using the combined brain morphological and clinical features, we achieved the best prediction of the outcome (MAE: 8.51, r = .90). Our findings suggest that the cross-modal plasticity allowing the superior temporal cortex and thalamus to process other modal sensory inputs reverses the initially lower volume when deafness becomes persistent. The middle temporal cortex processing higher-level language comprehension shows persistent negative correlations with disease duration, suggesting this area's association with degraded speech comprehensions due to long-term deafness. Morphological features combined with clinical variables might play a key role in predicting outcomes of cochlear implantation.

Concurrent and Selective Determination of Dopamine and Serotonin with Flexible WS2 /Graphene/Polyimide Electrode Using Cold Plasma.

Makers of point-of-care devices and wearable diagnostics prefer flexible electrodes over conventional electrodes. In this study, a flexible electrode platform is introduced with a WS2 /graphene heterostructure on polyimide (WGP) for the concurrent and selective determination of dopamine and serotonin. The WGP is fabricated directly via plasma-enhanced chemical vapor deposition (PECVD) at 150 °C on a flexible polyimide substrate. Owing to the limitations of existing fabrication methods from physical transfer or hydrothermal methods, many studies are not conducted despite excellent graphene-based heterostructures. The PECVD synthesis method can provide an innovative WS2 /graphene heterostructure of uniform quality and sufficient size (4 in.). This unique heterostructure affords excellent electrical conductivity in graphene and numerous electrochemically active sites in WS2 . A large number of uniform qualities of WGP electrodes show reproducible and highly sensitive electrochemical results. The synergistic effect enabled well-separated voltammetric signals for dopamine and serotonin with a potential gap of 188 mV. Moreover, the practical application of the flexible sensor is successfully evaluated by using artificial cerebrospinal fluid.

Lead-Free AE Sensor Based on BZT-BCT Ceramics.

In this study, an acoustic emission (AE) sensor was fabricated using lead-free Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) ceramics. The acoustic and electromechanical properties of the AE sensor were determined by the shapes of the piezoelectric ceramics. To optimize the AE sensor performance, the shapes of the ceramics were designed according to various diameter/thickness ratios (D/T) = 0.5, 1.0, 1.5, 2.0, 2.5, 3.0. The BZT-BCT ceramic with D/T = 1.0 exhibited excellent values of a piezoelectric charge coefficient (d33), piezoelectric voltage coefficient (g33), and electromechanical coupling factor (kp), which were 370 (pC/N), 11.3 (10-3 Vm/N), and 0.58, respectively. Optimum values of resonant frequency (fr) = 172.724 (kHz), anti-resonant frequency (fa) = 196.067 (kHz), and effective electromechanical coupling factor (keff) = 0.473 were obtained for the manufactured BZT-BCT ceramic with D/T = 1.0. The maximum sensitivity and frequency of the AE sensor made of the BZT-BCT ceramic with a D/T ratio of 1.0 were 65 dB and 30 kHz, respectively.

Candida auris colonization or infection of the ear: A single-center study in South Korea from 2016 to 2018.

Candida auris was first identified in Japan from specimens obtained from the ear, but most reports since have reported invasive infections or non-ear based cases. We reviewed all the microbiology records from a single center in South Korea from February 2016 to July 2018. One hundred eleven isolates were positive for C. auris from 79 patients. All 79 patients positive for C. auris had positive ear discharge samples. All but one of the patients with C. auris had been to the otorhinolaryngology clinic. Symptom-driven ear culture was done for all but one patient, whose culture was performed for surveillance. Ear discharges were mostly purulent (60%) or serous (34%). We performed the environmental cultures at the otorhinolaryngology outpatient clinic to evaluate the environmental contamination of C. auris, but C. auris was not isolated from medical equipment and environmental surfaces.

Fluoroscopic Balloon Dilation Using a Flexible Guide Wire to Treat Obstructive Eustachian Tube Dysfunction.

PURPOSE: To prospectively evaluate the midterm outcomes of fluoroscopic eustachian tube (E-tube) balloon dilation by using a flexible guide wire in patients with obstructive E-tube dysfunction. MATERIALS AND METHODS: From October 2016 to September 2017, adult outpatients with persistent otitis media who were unable to perform the Valsalva maneuver were prospectively enrolled. The analysis included 32 E-tubes from 31 patients (18 women, 13 men; mean age, 47 years old, range 25-72 years). Participants underwent fluoroscopic E-tube balloon dilation with a 0.035-inch flexible guide wire and a 6- × 20-mm balloon catheter. Clinical examinations to check for the ability to perform the Valsalva maneuver and otomicroscopy were conducted at 1 week and then at 1, 3, 12, and 18 months after the procedure. RESULTS: Balloon dilation was technically successful in all E-tubes. The mean time required for the procedure was 6.9 minutes (range, 5.8-10.3 minutes). The Valsalva maneuver was successful in opening 25 of 32 E-tubes (78.1%) at 3 months after balloon dilation. During the median follow-up of 15.9 months, failure of the Valsalva maneuver occurred in 4 of 25 improved E-tubes (16%), yielding a 2-year patency rate of 84%. CONCLUSIONS: The fluoroscopic balloon dilation results were encouraging, and using a flexible guide wire for E-tube balloon dilation did not cause a false passage.

Changes of visualised Eustachian tube lengths by age and position: Radiologic study in sitting and supine positions using cone beam and conventional CT.

OBJECTIVES: Patulous eustachian tube (ET) has been characterised by the visualisation of full-length ET on computed tomography (CT) results. We wanted to investigate the changes of visualised ET lengths by age in supine and sitting positions. DESIGN: Retrospective study. SETTING: Tertiary care academic referral centre. PARTICIPANTS: One hundred subjects who underwent cone beam CT (CBCT) in a sitting position and conventional CT in a supine position for non-otitis-related or dental complaints. MAIN OUTCOME MEASURES: Visualised ET lengths from the nasopharyngeal orifice measured by different positions and ages. RESULTS: Subjects did not show visualisation of full-length ET throughout the study. The visualised ET lengths (9.0 ± 2.5 mm) of the CBCT group were significantly larger than those (6.8 ± 2.3 mm) of the conventional CT group (P < 0.0001).Women showed longer visualised ET lengths than men in CBCT group (P < 0.001). The visualised ET lengths of the CBCT group were consistent or slightly increasing as a function of age (P = 0.06); however, the visualised ET lengths of the conventional CT group decreased as a function of age (P = 0.001). The slopes of regression lines of the two groups were significantly different. CONCLUSIONS: When in the supine position, the ET lengths gradually shortened as the subjects got older, most likely due to venous engorgement and the collapse of surrounding tissues; this finding thus suggests that CT in a supine position is an inappropriate method to diagnose patulous ET. The visualised ET lengths by CBCT in a sitting position were consistent throughout the different ages of the subjects and may be used as a diagnostic test for patulous ET.

Fluoroscopy-guided balloon dilation in patients with Eustachian tube dysfunction.

OBJECTIVES: To prospectively evaluate the technical feasibility and safety of fluoroscopy-guided balloon dilation in patients with Eustachian tube (ET) dysfunction. METHODS: Patients who could not do a Valsalva manoeuvre for more than 6 months and diagnosed with chronic otitis media or ET dysfunction were prospectively enrolled. A 0.035-in. guide wire and 6-mm long balloon catheter with a diameter of 2 mm were used to dilate the cartilaginous portion of the ET under fluoroscopic guidance. The balloon was inflated by manual injection twice for 1 min each time. Clinical outcomes were assessed by the patient's ability to perform a Valsalva manoeuvre, and symptoms were assessed using the 7-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7) score. RESULTS: Balloon dilation was attempted in a total of ten adult patients from October 2016 to March 2017. Technical success was achieved in all procedures (10/10). Ninety percent (9/10) of the balloons were fully dilated without waist deformity. There were no major complications. All patients were able to perform a Valsalva manoeuvre at the time of their last visit and/or improvement of at least one ETDQ-7 score. CONCLUSION: Fluoroscopy-guided balloon dilation seems to be technically feasible and safe in the treatment of ET dysfunction. KEY POINTS: • Fluoroscopy-guided balloon dilation without general anaesthesia was well-tolerated in all patients. • Location of the balloon catheter can be monitored during the procedure. • Inflation state of the balloon catheter can be monitored during the procedure. • Using guide-wire during the procedure would prevent false passage creation. • All patients had clinical improvement within 3 months after balloon dilation.

Fluoroscopic subtraction Eustachian tubography: initial feasibility test in a cadaver model.

OBJECTIVES: To evaluate the technical feasibility of direct Eustachian tube catheterisation and subtraction Eustachian tubography in a cadaver model. METHODS: A total of 12 separate sessions were performed on both sides of the Eustachian tube (ET) in six human cadavers. Cadavers were positioned for the submentovertical view on a fluoroscopy table. Endoscopy-guided ET selection was used in the first three cadavers, whereas fluoroscopy-guided ET selection was used in the remaining three. Eustachian tubography was performed by injecting 2 ml of contrast media through a 5-Fr catheter. We recorded the success of ET selection, number of attempts, procedure time, and tubography quality using native and subtraction images (range, 0-3). RESULTS: Both endoscopy- and fluoroscopy-guided selections were successfully performed in five of six sessions (83.3%). There were no statistically significant differences between the endoscopy- and fluoroscopy-guided procedures in terms of the number of attempts, procedure time, rate of immediate contrast leak to the middle ear cavity, and quality of tubography (p > 0.05). An excellent quality of tubography was obtained in 83.3% (10 of 12 sessions) of subtraction images and in 33.3% (4 of 12 sessions) of native images. The tubography quality score was significantly higher for the subtraction images than for the native images (p = 0.04). CONCLUSION: Subtraction Eustachian tubography using direct catheterisation seems to be technically feasible. The entire ET can be well visualised; thus, this technique can be used as a simple tool for assessment of ET function and anatomy. KEY POINTS: • Direct catheterisation of the Eustachian tube is technically feasible. • The entire Eustachian tube could be well visualised by direct Eustachian tubography. • Subtraction Eustachian tubography images have better image quality than native images. • Subtraction Eustachian tubography can provide objective assessment of ET function and anatomy.

Transnasal Placement of a Balloon-Expandable Metallic Stent: Human Cadaver Study of the Eustachian Tube.

PURPOSE: To investigate the technical feasibility of stent placement in the cartilaginous portion of the Eustachian tube (ET). MATERIALS AND METHODS: Twelve ETs of 6 cadavers were used. Two different-sized stents were placed on either the right (2.5 mm in diameter) or left (3.5 mm in diameter) side of the ET. The procedural feasibility was assessed by subtraction Eustachian tubography, computed tomography before and after the procedure, and fluoroscopic and endoscopic images. The stent location, inner luminal diameter of the stented ET, radiation dose, procedural time, and fluoroscopy time were analyzed. RESULTS: Stent placement was successful in 11 of 12 cadaveric specimens without procedure-related complications. In the 1 specimen, the balloon catheter with crimped stent was passed into the bony canal of the ET without any resistance. The distal end of the stent was located in the middle ear cavity. Stents were located within the cartilaginous portion of the ET (n = 1), the proximal tip bridging the nasopharyngeal orifice of the ET (n = 5), or the proximal end of the stent protruded from the tubal orifice (n = 5). The mean luminal diameter in the outer segment was significantly smaller than in the middle (P < .001) and inner (P < .001) segments. The mean procedure time was 128 ± 37 seconds. The mean radiation dose and fluoroscopy time of each cadaver were 3235.4 ± 864.8 cGy/cm2 and 139 ± 49 seconds, respectively. CONCLUSIONS: Stent placement of the ET under endoscopic and fluoroscopic guidance is technically feasible in a human cadaver model.

Fluoroscopic balloon diameter measurement at different pressures during Eustachian balloon dilation.

OBJECTIVES: To measure the diameter of inflated balloons at different pressures during Eustachian tube (ET) balloon dilation under fluoroscopic guidance. DESIGN: Prospective cohort study. SETTING: Tertiary academic referral centre. PARTICIPANTS: Eighteen patients who underwent ET balloon dilation with use of a balloon catheter, 20 mm long and 6 mm in diameter, under combined endoscopic and fluoroscopic guidance. MAIN OUTCOME MEASURES: Degrees of inflation at three different portions (proximal, middle and distal) of the balloon at controlled pressures (3, 5, 8 and 10 atmospheres [atm]) and at the maximum pressure manually applied. RESULTS: The mean proximal, middle and distal diameters of the inflated balloons were 5.3 ± 0.4 mm, 5.3 ± 0.4 mm and 4.9 ± 0.5 mm at 10 atm. The distal diameters were significantly smaller than middle and proximal diameters at all the pressures (P < 0.01). When compared to the distal diameter (100%, 4.9 ± 0.5 mm) at 10 atm, the distal diameters were 73% (3.6 ± 0.6 mm) at 3 atm, 88% (4.3 ± 0.5 mm) at 5 atm and 96% (4.7 ± 0.4 mm) at 8 atm. The distal diameter (4.1 ± 0.3 mm) at the maximum pressure manually applied was in between those at 3 and 5 atm. CONCLUSIONS: The distal diameter of the balloon increased significantly as a function of the pressure and most (88%) inflation occurred at a low pressure of 5 atm, which was sufficient to inflate the distal diameter of the balloon more than 3 mm. The manual pressurisation could inflate a balloon by as much as could be expected, at between 3 and 5 atm.

Microfabricated infuse-withdraw micropump component for an integrated inner-ear drug-delivery platform.

One of the major challenges in treatment of auditory disorders is that many therapeutic compounds are toxic when delivered systemically. Local intracochlear delivery methods are becoming critical in emerging treatments and in drug discovery. Direct infusion via cochleostomy, in particular, is attractive from a pharmacokinetics standpoint, as there is potential for the kinetics of delivery to be well-controlled. Direct infusion is compatible with a large number of drug types, including large, complex molecules such as proteins and unstable molecules such as siRNA. In addition, hair-cell regeneration therapy will likely require long-term delivery of a timed series of agents. This presents unknown risks associated with increasing the volume of fluid within the cochlea and mechanical damage caused during delivery. There are three key requirements for an intracochlear drug delivery system: (1) a high degree of miniaturization (2) a method for pumping precise and small volumes of fluid into the cochlea in a highly controlled manner, and (3) a method for removing excess fluid from the limited cochlear fluid space. To that end, our group is developing a head-mounted microfluidics-based system for long-term intracochlear drug delivery. We utilize guinea pig animal models for development and demonstration of the device. Central to the system is an infuse-withdraw micropump component that, unlike previous micropump-based systems, has fully integrated drug and fluid storage compartments. Here we characterize the infuse-withdraw capabilities of our micropump, and show experimental results that demonstrate direct drug infusion via cochleostomy in animal models. We utilized DNQX, a glutamate receptor antagonist that suppresses CAPs, as a test drug. We monitored the frequency-dependent changes in auditory nerve CAPs during drug infusion, and observed CAP suppression consistent with the expected drug transport path based on the geometry and tonotopic organization of the cochlea.

Long-Term Educational and Occupational Status of Prelingually Deaf Children Who Have Received a Cochlear Implant.

OBJECTIVE: To investigate the long-term educational and occupational status of prelingually bilateral deaf children who received a cochlear implant (CI) before the age of 7, and to identify factors that influence these outcomes. STUDY DESIGN: Retrospective chart review. SETTING: Single tertiary care center. METHODS: Seventy-one children who underwent CI surgery from 2000 to 2007 were included. The latest education and occupation status and word recognition score (WRS) were analyzed. RESULTS: The mean age at the time of surgery and the current age was 3.9 and 22.4 years. The age at CI showed a negative correlation with WRS. All subjects had graduated from high school or obtained an equivalent educational qualification. General high school graduates showed a higher WRS than those who attended a special education high school. The college entrance rate of CI patients (74.6% %) was comparable to that of the general population (72.5%). Subjects who went to college had a significantly better WRS than those who did not (51.4% vs 19.3%). Excluding 30 subjects currently enrolled in college, 26 (62%) of the remaining 41 were currently employed and engaged in various vocational activities, of which most (21 out of 26, 81%) were employed through vocational training institutes, or via special recruitment policy for the disabled. CONCLUSION: The long-term use of CI in prelingually deaf children enables not only speech perception but also produces comparable levels of education and employment to those of the general population. A good WRS and supportive policy were related to these successful outcomes.

Clinical Outcomes of Endoscopic Butterfly Inlay Cartilage Myringoplasty.

OBJECTIVE: To review a 3-year case series of endoscopic butterfly inlay cartilage myringoplasty performed by a single surgeon (W.S.K.) and analyze the clinical surgical outcomes. STUDY DESIGN: Retrospective study. SETTING: Tertiary care academic center. PATIENTS: We enrolled 60 ears with tympanic membrane (TM) perforation, receiving endoscopic inlay butterfly myringoplasty between 2019 and 2022. MAIN OUTCOMES AND MEASURES: We reviewed patients' demographics, size and location of TM perforation, operation time, complications, and postoperative pain evaluated by the numerical rating scale (NRS). We analyzed the graft uptake success rate in 5 weeks and the perforation closure rate in 4 months after surgery. We also compared the air-bone gap (ABG) before and after the surgery. RESULTS: Among the 60 ears included, the mean age was 57.0 years, and 78.3% (47 of 60) had small perforations. The average operation time was 48.9 ± 11.5 minutes, and the postoperative NRS was 2.0 ± 1.6. The immediate graft uptake success rate evaluated at postoperative 5 weeks was 96.7% (58 of 60), with myringitis occurring in three ears. Except for 11 patients lost to follow-up, the perforation closure rate evaluated at postoperative 4 months was 100% (49 of 49). The mean ABG significantly improved from preoperative status (8.87 ± 5.51 dB HL) to postoperative 4 months (6.22 ± 6.03 dB HL) ( p = 0.019). CONCLUSIONS: A single surgeon's success rate for endoscopic butterfly inlay cartilage myringoplasty was almost 100%. This surgical procedure is safe and effective, with a high graft success rate.

The Role of Measuring Preoperative Social Maturation Score in Children With Additional Needs Who Underwent Cochlear Implantation.

BACKGROUND AND OBJECTIVES: Additional needs refer to specific requirements or support for individuals with disabilities or syndromes. Intellectual ability is a crucial outcome determinant of a cochlear implant. The social quotient (SQ) is an indirect predictor of intellectual capacity and social skills. This study aimed to investigate the clinical significance of the SQ on children with additional needs who received cochlear implants. Subjects and. METHODS: This study included 24 patients with diagnosed developmental delays and syndromes, who demonstrated SQ scores of <70. Preoperative social skills were evaluated using the SQ. All patients underwent cochlear implantation (CI) surgery before 7 years of age. Outcomes were evaluated using the Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) and Categories of Auditory Performance (CAP) scores. Data were collected through a retrospective chart review. RESULTS: Children were categorized into three groups based on their SQ. There were no correlations between the preoperative SQ and IT-MAIS or CAP scores at 2 and 5 years of follow-up postoperatively. The CI outcomes of children with low SQ (<70) differed from those with normal development (SQ>70). In the low-SQ group, inner ear anomalies were observed in 10 (41.7%) patients. Although not statistically significant, these children exhibited a trend of lower average outcomes than children without inner ear anomalies. CONCLUSIONS: CI outcomes in children with additional needs positively affected auditory performance. Postoperative auditory and language skills tended to improve slowly in children with additional needs and a lower SQ. Over time, development gradually became more comparable to the other groups of children. However, this improvement was less than that observed in children without additional needs. Our findings support CI for children with additional needs as part of long-term auditory rehabilitation following surgery.

Combination of plasma with a honeycomb-structured catalyst for automobile exhaust treatment.

To activate a catalyst efficiently at low temperature by plasma for environmental control, we developed a hybrid reactor that combines plasma with a honeycomb-structured catalyst in a practical manner. The reactor developed generated stable cold plasma at atmospheric pressure because of the dielectric and conductive nature of the honeycomb catalyst by consuming low amounts of power. In this reactor, the applied voltage and temperature determined the balance between the oxidation and adsorption by the plasma and catalyst. The synergistic reaction of the plasma and catalyst was more effective at low temperatures, resulting in a reduction in a lowered light-off temperature.

Improvement in Acid Resistance of Polyimide Membranes: A Sustainable Cross-Linking Approach via Green-Solvent-Based Fenton Reaction.

In this study, we present a facile surface modification method using green solvents for a commercial polyimide (PI) nanofiltration membrane to exhibit good acid stability. To enhance acid stability, the PI organic solvent nanofiltration membrane was modified using Fenton's reaction, an oxidative cross-linking process, using environmentally friendly solvents: water and ethanol. The surface properties of the pristine and modified PI membranes were investigated and compared using various analytical tools. We studied the surface morphology using scanning electron microscopy, performed elemental analysis using X-ray photoelectron spectroscopy, investigated chemical bonds using attenuated total reflectance-Fourier transform infrared spectroscopy, and studied thermal stability using thermogravimetric analysis. The acid resistances of the pristine and modified membranes were confirmed through performance tests. The pristine PI nanofiltration membrane exposed to a 50 w/v% sulfuric acid for 4 h showed an increase in the normalized water flux to 205% and a decrease in the MgSO4 normalized rejection to 44%, revealing damage to the membrane. The membrane modified by the Fenton reaction exhibited a decline in flux and improved rejection, which are typical performance changes after surface modification. However, the Fenton-modified membrane exposed to 50 w/v% sulfuric acid for 4 h showed a flux increase of 7% and a rejection increase of 4%, indicating improved acid resistance. Furthermore, the Fenton post-treatment enhanced the thermal stability and organic solvent resistance of the PI membrane. This study shows that the acid resistance of PI membranes can be successfully improved by a novel and facile Fenton reaction using green solvents.

The experience of device failure after cochlear implantation.

BACKGROUND: The present study describes the treatment of patients at a tertiary institution who experienced device failure after Cochlear Implantation (CI), as well as identifying prodromic symptoms that could assist in the timely identification and management of device failure. STUDY DESIGN: Retrospective database review (January 2000-May 2017). SETTING: Single tertiary hospital. METHODS: Factors recorded included the etiology of hearing loss; age at first and revision CI surgeries; surgical information, including operation time and approach; electrical outcomes after implantation; device implanted; symptoms of device failure; history of head trauma; and audiologic outcomes as determined by categories of auditory performance (CAP). RESULTS: From January 2000 to May 2017, 1431 CIs were performed, with 27 (1.9%) undergoing revision surgeries due to device failure. The most common etiology of hearing loss was idiopathic (12/27), followed by cochlear hypoplasia (5/27). Mean age at initial CI was 11.8 (1-72) years, with 21 being pre-lingual and 6 being post-lingual. Of the total devices initially implanted, 80.5% were from Cochlear, 15.9% from MED-EL, and 3.5% from Advanced Bionics. The failure rates of these devices were 1.3%, 3.1%, and 10.0%, respectively. The most suggestive symptom of device failure was intermittent loss of signal. Mean CAP scores were 5.17 before reimplantation and 5.54 and 5.81 at 1- and 3-years, respectively, after reimplantation. CONCLUSION: The most suggestive symptom preceding device failure was intermittent loss of signal. Patients who present with this symptom should undergo electrical examination for suspected device failure. Audiologic outcomes showed continuous development despite revision surgeries.

Outcomes of Endoscopic Tympanoplasty for Large Perforations: A Multicenter Retrospective Study in South Korea.

OBJECTIVES: Endoscopic tympanoplasty (ET) provides minimally invasive transcanal access to the middle ear and improves middle ear visibility for the treatment of tympanic membrane (TM) perforations. However, the literature on surgical outcomes for large TM perforations is lacking and limited to small series. This study aimed to evaluate the clinical benefits of ET for large TM perforations. METHODS: This retrospective cohort study was conducted at nine tertiary referral hospitals in South Korea, where 252 patients who underwent ET as primary surgery from September 2019 to August 2021 were included. The outcome measures included the graft success rate and pre- and postoperative audiometric data. RESULTS: In 239 patients, the graft success rate of ET for large or subtotal perforations was 86.2% (206 patients), while the graft failure rate was 13.8% (33 patients). The graft failure rate was directly correlated with surgical techniques, including overlay and medial or lateral underlay tympanoplasty (P=0.027). Lateral underlay tympanoplasty showed the most favorable. RESULTS: Sex, laterality, etiology, site and size of perforation, operation time, and graft materials did not vary significantly between the graft success and failure groups (P>0.05). The mean air-bone gap (ABG) improved significantly in both groups (graft success group: 10.0±0.6 dB and graft failure group: 7.7±0.3 dB; P<0.001). However, the ABG improvement did not significantly differ between the groups. Analysis of covariance revealed that the postoperative 500-Hz bone conduction threshold improved after successful ET (adjusted coefficient, -11.351; 95% confidence interval, -21.491 to -1.212; P=0.028). CONCLUSION: This study involved the largest population to date of large TM perforations treated by ET. The study findings suggest that ET is feasible and effective in treating large TM perforations.