Comparison of Two Measurement Paradigms to Determine Electrically Evoked Cochlear Nerve Responses and Their Correlation to Cochlear Nerve Cross-section in Infants and Young Children With Cochlear Implant.

INTRODUCTION: Electrically evoked compound action potentials (ECAPs) are used for intra-/postoperative monitoring with intracochlear stimulation of cochlear implants. ECAPs are recorded in MED-EL (Innsbruck, Austria) implants using auditory response telemetry (ART), which has been further developed with automatic threshold determination as AutoART. The success of an ECAP measurement also depends on the number of available spiral ganglion cells and the bipolar neurons of the cochlear nerve (CN). It is assumed that a higher population of spiral ganglion cell implies a larger CN cross-sectional area (CSA), which consequently affects ECAP measurements. METHODS: Intraoperative ECAP measurements from 19 implanted ears of children aged 8 to 18 months were retrospectively evaluated. A comparison and correlation of ART/AutoART ECAP thresholds/slopes at electrodes E2 (apical), E6 (medial), E10 (basal), and averaged E1 to E12 with CN CSA on magnetic resonance imaging was performed. RESULTS: A Pearson correlation of the ART/AutoART ECAP thresholds/slopes for E2/E6/E10 and the averaged electrodes E1 to E12 showed a significant correlation. The CN CSA did not correlate significantly with the averaged ART/AutoART ECAP thresholds/slopes across all 12 electrodes. SUMMARY: AutoART provides reliable measurements and is therefore a suitable alternative to ART. No significant influence of CN CSA on ECAP thresholds/slopes was observed. A predictive evaluation of the success of ECAP measurements based on CN CSA for a clinical setting cannot be made according to the present data.

ART and AutoART ECAP measurements and cochlear nerve anatomy as predictors in adult cochlear implant recipients.

PURPOSE: The purpose of this retrospective study is to compare the results of electrically evoked compound action potential (ECAP) measurements using automatic auditory response telemetry (AutoART) with those obtained by ART in adults. The study also aimed to evaluate the predictive value of intraoperative ART and AutoART ECAPs for speech intelligibility (SI) and hearing success (HS), and to determine if cochlear nerve (CN) cross-sectional area (CSA) obtained preoperatively by magnetic resonance imaging (MRI) scans could predict ART and AutoART ECAPs and SI and HS outcome. METHODS: The study analyzed and correlated ART and AutoART ECAP thresholds at electrodes E2, E6, and E10, as well as averaged ECAP thresholds over electrodes E1-E12, using data from 32 implants. Correlations were also examined for ART and AutoART ECAP slopes. In addition, averaged ART and AutoART ECAP thresholds and slopes over all 12 electrodes for each participant were correlated with CN CSA measured from MRI sequences. SI of the monosyllabic Freiburg Speech Test at 65 dB sound pressure level was examined along with averaged ART and AutoART thresholds and slopes over all 12 electrodes. A parallel analysis was performed for HS, derived from the difference between baseline and 6-month SI. Finally, correlations between CN CSA and SI, as well as CN CSA and HS were examined. RESULTS: The results of the study showed a significant positive correlation between ART and AutoART ECAP thresholds and as well as slopes for E2, E6, E10 and averaged thresholds and slopes of E1-E12. However, no significant correlation was observed between ART and AutoART averaged ECAP thresholds and slopes and either SI and HS or CN CSA. Furthermore, no significant correlation was found between CN CSA and SI and HS. CONCLUSION: While AutoART is a reliable and safe program for measuring ECAPs in adults, the study found no preoperative prognostic information on intraoperative ECAP results using parameters extracted from current MRI sequences or pre-/intraoperative information on subsequent hearing outcome using ECAP and CN CSA.

Long-term results and quality of life after vibrant soundbridge implantation (VSBs) in children and adults with aural atresia.

PURPOSE: The aim of this study was to evaluate the long-term effectiveness and acceptance of the active middle ear implant system Vibrant Soundbridge (VSB®, MED-EL, Austria) in patients with aural atresia or aplasia (children and adults). METHODS: Data from 51 patients (mean age 13.9 ± 11.3 years), 42 (79.2%) children and adolescents, and 11 (20.8%) adults) who received a VSB implant between 2009 and 2019 at the Department of Otolaryngology at LMU Clinic Großhadern, Munich were included in the study. Pure-tone audiometry, speech recognition in a quiet environment and in a noisy environment were performed preoperatively, during the first fitting of the audio processor, after 1-3 years, after 3-5 years, and after 5 years (if possible). The follow-up period ranged from 11 to 157 months with a mean of 58.6 months (4.8 years). Furthermore, the benefit of the VSB was evaluated by self-assessment questionnaires (Speech, Spatial, and Qualities of Hearing Scale, respectively, for parents). RESULTS: Significant improvements were observed in hearing and speech comprehension immediately after the initial fitting of the VSB system (mean hearing gain 38.4 ± 9.4 dB HL) and at follow-up intervals (1-3, 3-5 and after 5 years) for children and adults (p < 0.01). The values remained stable over the long-term, indicating a sustained functional gain from the VSB (mean hearing gain 38.9 ± 9.2 dB HL). The results of the self-assessments affirm the positive influence on hearing and speech comprehension with the VSB. With the VSB, there was an improvement of 41.3 ± 13.7% in the Freiburg monosyllable test. CONCLUSION: These results (a stable hearing gain over the long term, a good tolerance of the implant and an improvement in quality of life) affirm the recommendation for using the active middle ear implant VSB as early as permitted for aural atresia and aplasia patients. This study represents the audiometric results with the (to date) largest collective of aural atresia patients and with a long follow-up period.

Significance of endolymphatic sac surgery with and/or without simultaneous cochlea implant surgery in respect of vertigo control and speech perception in patients with Menière's disease.

PURPOSE: The focus on treating patients with Menière's Disease (MD) lies on the reduction of vertigo attacks and the preservation of sensory function. Endolympathic hydrops is considered as an epiphenomenon in MD, which can potentially be altered by endolymphatic sac surgery (ESS). Purpose of the study was to investigate the influences on vertigo control through manipulation of the perilymphatic system with or without ESS. METHODS: Retrospective data analysis of 86 consecutive patients with MD according to current diagnostic criteria after endolymphatic sac surgery alone (ESSalone; n = 45), cochlear implantation (CI) alone (CIalone; n = 12), and ESS with CI (ESS + CI; n = 29), treated at a tertiary referral center. MAIN OUTCOME MEASURES: vertigo control, speech perception pre- and postoperatively. RESULTS: Gender, side, and preoperative treatment were similar in all groups. Age was younger in the ESSalone-group with 56.2 ± 13.0 years (CIalone = 64.2 ± 11.4 years; ESS + CI = 63.1 ± 9.7 years). Definitive MD was present in all the CIalone, in 79.3% of the ESS + CI and in 59.6% of the ESSalone-patients. Likewise, vertigo control rate was 100% in the CIalone, 89.7% in the ESS + CI and 66.0% in the ESSalone-group. CONCLUSIONS: Vertigo control was improved in all three groups, however, superior in groups treated with CI, potentially contributed by the manipulation of both the endo- and perilymphatic systems. A more systematic characterization of the patients with larger case numbers and documentation of follow up data would be needed to evaluate a clinical effect more properly.

Comparison of speech perception in bimodal cochlear implant patients with respect to the cochlear coverage.

BACKGROUND: The hearing success of patients with bimodal fitting, utilizing both a cochlear implant (CI) and a hearing aid (HA), varies considerably: While some patients benefit from bimodal CI and HA, others do not. OBJECTIVES: This retrospective study aimed to investigate speech perception in bimodally fitted patients and compare it with the cochlear coverage (CC). METHODS: The CC was calculated with the OTOPLAN software, measuring the cochlear duct length on temporal bone CT scans of 39 patients retrospectively. The patients were categorized into two groups: CC ≤ 65% (CC500) and CC > 65% (CC600). Monaural speech intelligibility for monosyllables at a sound pressure level (SPL) of 65 dB in a free-field setting was assessed before and after CI at various time points. The two groups, one with preoperative HA and one with postoperative CI, were compared. Additionally, speech intelligibility was correlated with CC in the entire cohort before CI and at the last available follow-up (last observation time, LOT). RESULTS: Overall, there was no significant difference in speech intelligibility between CC500 and CC600 patients, with both groups demonstrating a consistent improvement after implantation. While CC600 patients tended to exhibit earlier improvement in speech intelligibility, CC500 patients showed a slower initial improvement within the first 3 months but demonstrated a steeper learning curve thereafter. At LOT, the two patient groups converged, with no significant differences in expected speech intelligibility. There was no significant relationship between unimodal/unilateral free-field speech intelligibility and CC. Interestingly, patients with a CC of 70-75% achieved the highest speech intelligibility. CONCLUSION: Despite of the lack of a significant correlation between CC and speech perception, patients appeared to reach their maximum in unimodal/unilateral speech perception primarily at a coverage level of 70-75%. Nevertheless, further investigation is warranted, as CC500 was associated with shorter cochlear duct length, and different types of electrodes were used in both groups.

[Speech perception as a function of cochlear coverage-comparison in bimodally hearing cochlear implant patients. German version]. / Sprachverstehen in Abhängigkeit von der cochleären Abdeckung ­ Vergleich bei bimodal versorgten Cochleaimplantatpatienten.

BACKGROUND: Hearing success in bimodally hearing patients with a cochlear implant (CI) and a hearing aid (HA) exhibits different results: while some benefit from bimodal CI and HA, others do not. OBJECTIVE: The aim of this study was to investigate hearing success in terms of speech perception in bimodally fitted patients in relation to the cochlear coverage (CC) of the CI electrodes. MATERIALS AND METHODS: Using the OTOPLAN software (CAScination AG, Bern, Switzerland), CC was retrospectively measured from CT scans of the temporal bone of 39 patients, who were then categorized into two groups: CC ≤ 65% (CC500) and CC > 65% (CC600). Monaural speech intelligibility for monosyllables at a sound pressure level (SPL) of 65 dB in open field was assessed at various timepoints, preoperatively with HA and postoperatively with CI, and compared between the groups. In addition, speech intelligibility was correlated with CC in the entire cohort before surgery and during follow-up (FU). RESULTS: Overall, no significant differences in speech intelligibility were found between CC500 and CC600 patients at any of the FU timepoints. However, both CC500 and CC600 patients showed a steady improvement in speech intelligibility after implantation. While CC600 patients tended to show an earlier improvement in speech intelligibility, CC500 patients tended to show a slower improvement during the first 3 months and a steeper learning curve thereafter. The two patient groups converged during FU, with no significant differences in speech intelligibility. There was no significant relationship between unimodal/unilateral free-field speech intelligibility and CC. However, patients with a CC of 70-75% achieved maximum speech intelligibility. CONCLUSION: Despite a nonsignificant correlation between CC and speech discrimination, patients seem to reach their maximum in unimodal/unilateral speech understanding mainly at 70-75% coverage. However, there is room for further investigation, as CC500 was associated with a shorter cochlear duct length (CDL), and long and very long electrodes were used in both groups.

Differentiating methicillin resistant and susceptible Staphylococcus aureus from ocular infections using photoacoustic labeling.

Introduction: Antibiotic resistance in bacterial species constitutes a growing problem in the clinical management of infections. Not only does it limit therapeutic options, but application of ineffective antibiotics allows resistant species to progress prior to prescribing more effective treatment to patients. Methicillin resistance in Staphylococcus aureus is a major problem in clinical infections as it is the most common hospital acquired infection. Methods: We developed a photoacoustic flow cytometer using engineered bacteriophage as probes for rapid determination of methicillin resistance in Staphylococcus aureus with thirteen clinical samples obtained from keratitis patients. This method irradiates cells under flow with 532 nm laser light and selectively generates acoustic waves in labeled bacterial cells, thus enabling detection and enumeration of them. Staphylococcus aureus isolates were classified from culture isolation as either methicillin resistant or susceptible using cefoxitin disk diffusion testing. The photoacoustic method enumerates bacterial cells before and after treatment with antibiotics. Decreasing counts of bacteria after treatment indicate susceptible strains. We quantified the bacterial cells in the treated and untreated samples. Results: Using k-means clustering on the data, we achieved 100% concordance with the classification of Staphylococcus aureus resistance using culture. Discussion: Photoacoustics can be used to differentiate methicillin resistant and susceptible strains of bacteria from ocular infections. This method may be generalized to other bacterial species using appropriate bacteriophages and testing for resistance using other antibiotics.

The RonchAP® palatinal device: A conservative approach in treating obstructive sleep apnea syndrome-a randomized, controlled study.

PURPOSE: The aim of the present study was to assess the efficacy of the Ronch®AP palatal device in treating patients with moderate and severe forms of obstructive sleep apnea syndrome. METHODS: In a randomized controlled trial 22 patients were examined with the Ronch®AP palatal device after 4 weeks of usage. Their results were compared to a control group of 30 patients who did not receive any treatment during this time. All patients included did not tolerate CPAP therapy. Among other parameters the apnea-hypopnea index (AHI) was measured using nocturnal cardiorespiratory polysomnography. Daytime sleepiness was assessed using Epworth Sleepiness Scale. Pittsburgh Sleep Quality Index was used to analyze sleep quality. RESULTS: Using the Ronch®AP palatal device AHI was reduced from an average of 35.34 ± 14.9/h to 19.18 ± 14.93/h, whereas the control group only showed a minimal mean reduction from 31.32 ± 12.76/h to 29.37 ± 17.11/h. The difference in reduction between the two randomized groups was highly significant (d = - 14.2, 95% CI 5.9-22.6, t = 3.4, df = 49.9, p = 0.001). Epworth Sleepiness Scale score was lowered from 9.18 ± 4.73 to 7.82 ± 4.14 on average and sleep quality improved by - 1.91 ± 2.31. Both changes were also statistically relevant (p < 0.005). CONCLUSIONS: The Ronch®AP device is an effective alternative treatment option for patients suffering from moderate and severe forms of obstructive sleep apnea syndrome and not tolerating CPAP therapy. TRIAL REGISTRATION NUMBER: 407-16 with approval from the local ethical committee (Ethikkommission der Medizinischen Fakultät der LMU München).

Anatomical Variations of the Epitympanum and the Usable Space for Middle Ear Implants Analyzed With CT-assisted Imaging Using a Tablet-based Software.

OBJECTIVE: To evaluate interindividual anatomical variations of the epitympanum and the usable space for implantation of active middle ear implants (AMEI) as well as the usefulness of a tablet-based software to assess individual anatomy on computed tomography (CT) scans. PATIENTS: CT scans of 126 patients, scheduled for cochlea implantation (50.8% men; 0.6-90.0 yr) without middle ear malformations or previous middle ear surgery and with slice thickness ≤0.7 mm were analyzed. MAIN OUTCOME MEASURES: Since no standardized measurements to assess the size of the epitympanum are available, relevant distances were defined according to anatomical landmarks. Three independent raters measured these distances using a tablet-based software. Interrater correlation was computed to evaluate the quality of the measurement process. Descriptive data were analyzed for validation and for evaluation of interindividual anatomical variations. Influence of age and sex on the taken measurements was assessed. RESULTS: No relevant correlation between age or sex and the anatomy of the epitympanum was found. Interrater correlation ranged from Spearman's ρ = 0.3-0.9 and there were significant differences between individual rater results for various combinations. Descriptive data revealed high interindividual anatomical variance of the epitympanum, especially regarding the distance between incus and skull base. CONCLUSION: The reported descriptive data regarding the anatomy of the epitympanum emphasizes the importance of preoperative planning, especially since the height of the epitympanum showed great interindividual variance potentially limiting implantation of AMEIs. The herein used tablet-based software seems to be convenient for preoperative assessment of individual anatomy in the hand of otosurgeons.

Cochlear Implant Electrode Tip Fold-Over: Our Experience With Long and Flexible Electrode.

OBJECTIVE: The aim of this study was to retrospectively investigate if there is any incidence of electrode tip fold-over with 31.5 mm long and flexible lateral wall electrodes implanted in two high-volume Cochlear Implant (CI) centers in Germany. In addition, a detailed literature review was performed to capture all the peer-reviewed publications reporting on tip fold-over with CI electrodes from different CI brands for comparison. METHODS: Post-operative X-ray images of FLEX SOFT electrode from MED-EL in Stenver's view were retrospectively investigated for the presence of electrode tip fold-over from 378 consecutive cases in two high-volume CI centers in Germany. All patients were implanted between 2010 and 2018 by three individual experienced CI surgeons using round window and extended round window approach for CI electrode insertion. A literature review was performed following a thorough PubMed (https://www.ncbi.nlm.nih.gov/pubmed/) search using the keywords "cochlear implant electrode tip fold-over" or "cochlear implant electrode tip roll-over" to capture articles that were published until December 2020 in English language only. Articles selection was based on electrode-related issues investigated only in-patient cases applying imaging modality. Those studies investigated tip fold-over in cadaveric temporal bones and cases with inner-ear malformation excluded. RESULTS: No single case of tip fold-over was clinically detected from the retrospective investigation of post-operative X-ray images from 378 consecutive cases. The electrode angular insertion depth as measured applying the cochlear coordinate system, varied from a minimum of 560° to a maximum of 720°. The literature review on the tip fold-over issue resulted in 24 peer-reviewed published articles in total. Tip fold-over with pre-curved modiolar-hugging electrodes was reported in 85 cases out of 1,606 implantations making an incidence rate of 5.3%. With the straight lateral wall electrodes, the tip fold-over was reported in four cases out of 398 implantations making an incidence rate of 1%, not including the number of implantations reported in the current study. Otherwise it would be 0.5%. CONCLUSION: Electrode tip fold-over with 31.5 mm long flexible lateral wall electrodes is highly exceptional and this can be generalized to any of the straight lateral wall electrodes from any CI brand. The literature review on tip fold-over revealed an incidence rate of 5.3% with pre-curved or modiolar-hugging electrodes and 1% with straight lateral wall electrodes from CI brands. Including this series of 0% tip fold-over, the incidence rate of electrode tip fold-over with LW electrode type would be 0.5%.

Audiological results and subjective benefit of an active transcutaneous bone-conduction device in patients with congenital aural atresia.

PURPOSE: To review functional and subjective benefit after implantation of an active transcutaneous bone conduction device (BCD) in patients with congenital microtia with atresia or stenosis of the external auditory canal. METHODS: Retrospective chart analysis and questionnaire on the subjective impression of hearing ( Speech, Spatial and Qualities of Hearing Scale (SSQ-B) of patients treated between 2012 and 2015. RESULTSRESULTS: 18 patients (24 ears) with conductive or mixed hearing loss in unilateral (n = 10) or bilateral (n = 8) atresia were implanted with a BCD. No major complications occurred after implantation. Preoperative unaided air conduction pure tone average at 0.5, 1, 2 and 4 kHz (PTA 4 ) was 69.2 ± 11.7 dB, while postoperative aided PTA 4 was 33.4 ± 6.3 dB, resulting in a mean functional hearing gain of 35.9 +/- 15.6 dB. Preoperatively, the mean monosyllabic word recognition score was 22.9 % ± 22.3 %, which increased to 87.1 % +/- 15.1 % in the aided condition. The Oldenburger Sentence Test at S0N0 revealed a decrease in signal-to-noise-ratio from - 0.58 ± 4.40 dB in the unaided to - 5.67 ± 3.21 dB in the postoperative aided condition for all patients investigated. 15 of 18 patients had a subjective benefit showing a positive SSQ-B score (mean 1.7). CONCLUSION: The implantation of an active bone conduction device brings along subjective and functional benefit for patients with conductive or combined hearing loss.

Outcome of Auricular Reconstruction with Porous Polyethylene Frameworks: Our 10 Years of Experience with 113 Children and Adults.

This study evaluates the surgical outcome and patient benefit after auricular reconstruction with porous polyethylene frameworks and temporoparietal fascia flaps in both children and adults. A total of 161 patients who had undergone auricular reconstruction between 2003 and 2014 by doctors in our department were asked to answer both a validated health-related quality-of-life questionnaire (Glasgow Benefit Inventory or Glasgow Children's Benefit Inventory) and a questionnaire reporting satisfaction, complaints, and complications with the reconstructed pinna. Furthermore, postoperative surgical complications were recorded. A total of 113 patients (89 individuals older than 14 and 24 children under the age of 14) returned the questionnaires. About 80% of the patients were satisfied with the results of their auricular reconstruction. The main complaints concerned scars and the shape. Patients' quality of life was correlated with their postoperative aesthetic satisfaction. Thus, framework extrusion was the principal factor affecting patients' satisfaction, whereas treatable postoperative complications did not interfere with the overall quality of life. Interestingly, children indicated greater benefit from auricular reconstruction than older patients. With regard to the patient's feeling of being physically healthy after auricular reconstruction, partial pinna reconstruction and reconstruction without simultaneous hearing restoration should be very carefully considered. Auricular reconstruction using a porous polyethylene framework significantly increases the patients' health-related quality of life and leads to significant patient satisfaction, especially in the case of younger patients.

Variation of the cochlear anatomy and cochlea duct length: analysis with a new tablet-based software.

PURPOSE: In cochlear implantation, thorough preoperative planning together with measurement of the cochlear duct length (CDL) assists in choosing the correct electrode length. For measuring the CDL, different techniques have been introduced in the past century along with the then available technology. A tablet-based software offers an easy and intuitive way to visualize and analyze the anatomy of the temporal bone, its proportions and measure the CDL. Therefore, we investigated the calculation technique of the CDL via a tablet-based software on our own cohort retrospectively. METHODS: One hundred and eight preoperative computed tomography scans of the temporal bone (slice thickness < 0.7 mm) of already implanted FLEX28™ and FLEXSOFT™ patients were found eligible for analysis with the OTOPLAN software. Measurements were performed by two trained investigators independently. CDL, angular insertion depth (AID), and cochlear coverage were calculated and compared between groups of electrode types, sex, sides, and age. RESULTS: Mean CDL was 36.2 ± 1.8 mm with significant differences between sex (female: 35.8 ± 0.3 mm; male: 36.5 ± 0.2 mm; p = 0.037), but none concerning side or age. Differences in mean AID (FLEX28: 525.4 ± 46.4°; FLEXSOFT: 615.4 ± 47.6°), and cochlear coverage (FLEX28: 63.9 ± 5.6%; FLEXSOFT: 75.8 ± 4.3%) were significant (p < 0.001). CONCLUSION: A broad range of CDL was observed with significant larger values in male, but no significant differences concerning side or age. Almost every cochlea was measured longer than 31.0 mm. Preoperative assessment aids in prevention of complications (incomplete insertion, kinking, tipfoldover), attempt of atraumatic insertion, and addressing individual necessities (hearing preservation, cochlear malformation). The preferred AID of 720° (two turns of the cochlea) was never reached, opening the discussion for the requirement of longer CI-electrodes versus a debatable audiological benefit for the patient in his/her everyday life.

Multicenter Results With an Active Transcutaneous Bone Conduction Implant in Patients With Single-sided Deafness.

OBJECTIVE: To evaluate the audiological and subjective benefit from hearing rehabilitation with an active bone conduction implant in subjects with single-sided sensorineural deafness (SSD). STUDY DESIGN: Prospective, multicenter, single-subject repeated measures. SETTING: Tertiary referral center, five clinics in Germany and Switzerland. PATIENTS: Seventeen subjects aged 18 years and older with severe to profound unilateral sensorineural hearing loss and contralateral normal hearing were followed up for 24 months. INTERVENTION: Active bone conduction implant. MAIN OUTCOME MEASURES: Speech understanding in noise was assessed in three situations: with signal from front, deaf, or normal hearing side (with noise from front in all set-ups). Subjective benefit was evaluated using the Speech, Spatial, and Qualities of Hearing (SSQ-B) and Bern Benefit in Single-Sided Deafness (BBSS) questionnaire. RESULTS: When the signal was coming from the deaf side the mean improvement of the speech reception threshold in noise ranged from 1.5 up to 2.2 dB with the device and was statistically and clinically significant at all tested timepoints. No significant difference between the aided and unaided situation was found when signal and noise were coming from the front. With the signal from the normal hearing side no clinically significant difference, that is, greater than 1 dB between the aided and unaided situation was found. The SSQ-B and BBSS questionnaire showed an overall improvement with no significant difference between time points. CONCLUSIONS: The study demonstrates long-term efficacy and benefit of the device in adults with SSD. Patients reported substantial and persistent subjective benefit from the active bone conduction implant.

Photoacoustic discrimination of antibiotic-resistant and sensitive Staphylococcus aureus isolates.

OBJECTIVES: Bacteremia is a serious and potentially lethal condition. Staphylococcus aureus is a leading cause of bacteremia and methicillin-resistant S. aureus (MRSA) accounts for more than a third of the cases. Compared to methicillin-sensitive S. aureus, MRSA is more than twice as likely to be fatal. Furthermore, subpopulations of seemingly isogenic bacteria may exhibit a range of susceptibilities, often called heterogenous resistance. These heterogeneous antibiotic-resistant infections are often misdiagnosed as hospital-acquired secondary infections because there are no clinically used tests that can differentiate between homogeneous and heterogeneous antibiotic resistance. We describe the development and proof of concept of rapid bacterial identification using photoacoustic flow cytometry and labeled bacteriophages with the characterization and differentiation of heterogeneous antibiotic-resistant bacterial infections. METHODS: In photoacoustic flow cytometry, pulsed laser light is delivered to a sample flowing past a focused transducer and particles that absorb laser light create an acoustic response. Optically labeled bacteriophage are added to a bacterial mixture that flows through the photoacoustic chamber. The presence of target bacteria is determined by bound labeled phage which are detected photoacoustically. Incubation of bacterial samples in the presence and absence of the antibiotic daptomycin creates a difference in bacterial cell numbers that is quantified using photoacoustic flow cytometry. RESULTS: Four clinical isolates were tested in the presence and absence of daptomycin. Photoacoustic events for each isolate were recorded and compared to growth curves. Samples treated with daptomycin fell into three categories: resistant, susceptible, and heterogeneous resistant. CONCLUSIONS: Here we show a method to determine the presence of bacteria as a marker for bloodstream infection level and antibiotic sensitivity in less than 4 hours. Additionally, these results show an ability to identify heterogeneous resistant strains that are often misidentified.

Stapes and Stapes Revision Surgery: Preoperative Air-Bone Gap Is a Prognostic Marker.

OBJECTIVE: Stapes surgery is considered an effective treatment in otosclerosis, but controversy remains regarding predictors of surgical outcome. STUDY DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: One hundred sixty three cases of stapes surgery between 2012 and 2019 were reviewed. MAIN OUTCOME MEASURES: Primary outcome measures were relative hearing improvement (relHI), defined as preoperative minus postoperative air conduction divided by preoperative air-bone gap (ABG), as well as relative ABG closure (relABGc), defined as preoperative ABG minus postoperative ABG divided by preoperative ABG. Univariate and multivariate linear regression analyses were performed to determine independent predictors for these outcomes. RESULTS: Higher preoperative bone conduction (BC) and primary surgery (compared with revision) were independently associated with increased relHI (p = 0.001 and p = 0.004, respectively). Lower preoperative BC, higher preoperative ABG, primary surgery, and age were independently associated with increased relABGc (p = 0.0030, p < 0.001, p = 0.0214, and p = 0.0099, respectively). Sex did not predict surgical outcome. In patients with less than 20 dB preoperative ABG, likelihood of negative relABGc was increased (compared with 20-30 dB or >30 dB preoperative ABG, p = 0.0292, Fisher's exact test). This tendency was not significant for relHI (p = 0.074). CONCLUSIONS: Our findings demonstrate that calculating HI and ABGc in relation to preoperative ABG can reliably predict outcomes of stapes surgery. Both primary and revision stapes surgery are effective treatment options, but relative improvement is higher in primary cases. Preoperative BC, preoperative ABG, and age predict surgical outcomes as well. Otosclerosis patients with low preoperative ABG, especially less than 20 dB, should be counseled and selected cautiously regarding stapes surgery.

Image-guided robotic radiosurgery for glomus jugulare tumors-Multicenter experience and review of the literature.

BACKGROUND: Glomus jugulare tumors (GJTs) are challenging to treat due to their vascularization and location. This analysis evaluates the effectiveness and safety of image-guided robotic radiosurgery (RRS) for GJTs in a multicenter study and reviews the existing radiosurgical literature. METHODS: We analyzed outcome data from 101 patients to evaluate local control (LC), changes in pretreatment deficits, and toxicity. Moreover, radiosurgical studies for GJTs have been reviewed. RESULTS: After a median follow-up of 35 months, the overall LC was 99%. Eighty-eight patients were treated with a single dose, 13 received up to 5 fractions. The median tumor volume was 5.6 cc; the median treatment dose for single-session treatments is 16 Gy, and for multisession treatments is 21 Gy. Fifty-six percentage of patients experienced symptom improvement or recovered entirely. CONCLUSIONS: RRS is an effective primary and secondary treatment option for GJTs. The available literature suggests that radiosurgery is a treatment option for most GJTs.

Evaluating the didactic value of 3D visualization in otosurgery.

INTRODUCTION: Improvements of surgical visualization add value to the quality of clinical routine and offer the opportunity to improve surgical education of medical staff. The aim of this study was to determine whether otorhinolaryngology trainees gain additional comprehension of the anatomical structures and the surgical site when 3D visualization is used. METHODS: Data were collected from ENT trainees of microsurgical courses of the middle ear, inner ear and lateral skull base at four university ENT departments (Charité (Berlin), Martin Luther University Halle-Wittenberg (Halle/Saale), Ludwig Maximilian University (Munich) and Rostock University Medical Center). Participants were asked to complete a questionnaire assessing the subjective value of identical surgical field visualization in 3D for surgeon and observer. RESULTS: A total of 112 participants completed the questionnaire. The majority of participants stated a high additional value of 3D visualization compared to 2D visualization, with 75% fully agreeing to the statement that 3D visualization of the surgical field is superior to perceive the anatomical topography and structures compared to 2D representation. Participants encouraged the storage of data in online learning platforms. CONCLUSION: The results show that 3D visualization with identical imaging for surgeon and observer is a useful tool in teaching of microsurgery. It addresses perception of anatomical topography and structures as well as conception of the surgical workflow.

Single-session image-guided robotic radiosurgery and quality of life for glomus jugulare tumors.

BACKGROUND: Limited data are available on the efficacy and impact on the quality of life (Qol) of single-session image-guided robotic radiosurgery (RRS) for glomus jugulare tumors (GJTs). This study investigates the role of RRS in the management of GJTs and reviews the RRS literature. METHODS: We analyzed 53 GJT patients treated with RRS to evaluate the safety, local control, clinical outcome, and Qol assessed by the SF12v2. RESULTS: The local control was 98% at a median follow-up of 38 months. The median tumor volume was 4.3 cc and tumors were treated with a median dose of 16.5 Gy. At the last follow-up, 35 patients had recovered from their symptoms or experienced symptom improvement. Qol analyses showed no significant decline while bodily pain significantly decreased. CONCLUSIONS: RRS is a safe and efficient tool for the treatment of GJTs. Qol of patients after treatment is stable and tends to improve over time.

Comparison of ABR and ASSR using NB-chirp-stimuli in children with severe and profound hearing loss.

INTRODUCTION: Objective techniques for hearing threshold estimation in infants and children with profound or severe hearing loss play a key role in pediatric audiology to prevent speech acquisition disorders by choosing the adequate therapy. Auditory brainstem responses and auditory steady-state responses are available for frequency-dependent hearing threshold estimations and both techniques show strong correlations. However, various systems and stimuli are available, which is one reason why comparison is challenging, and, so far, no single "gold standard" could be established for hearing threshold estimation in children suffering from profound or severe hearing loss. The aim of the study was to compare hearing threshold estimations in children with profound or severe hearing loss derived with narrow-band CE-chirps evoked auditory brainstem responses and auditory steady-state response. SUBJECTS: and Methods: 71 children (121 ears) with an age from 3 month to 15 years were measured with the Interacoustics Eclipse EP25 ABR system® (Denmark) with narrow-band CE-chirps® at 500, 1000, 2000 and 4000 Hz under identical conditions. RESULTS: Auditory brainstem responses and auditory steady-state responses highly correlate (r = 0.694, p < 0.001). Correlation coefficients differ depending on the center frequency and patient age. Generally, auditory steady-state responses show a better hearing threshold than auditory brainstem responses or a remaining hearing threshold when auditory brainstem responses could not be obtained. In approximately 15% of cases this would have affected the therapeutic strategy when only taking one technique into account. CONCLUSION: Auditory brainstem responses and auditory steady-state responses should be jointly used in the diagnostic approach in children with suspected profound or severe hearing loss.