Purpose of Chapter: This chapter highlights the recent advances in etiology, diagnostic evaluation, and management of vestibular neuritis (VN). Recent Findings: The viral hypothesis has been strengthened with new evidence as the main etiology of VN. Recent evidence indicates that bedside oculomotor findings play a critical role in differentiating VN from stroke. The implementation of cervical and ocular vestibular evoked myogenic potential, and video head impulse test in vestibular function testing has made it possible to diagnose selective damage of the vestibular nerves. The management of the acute phase of VN is primarily medical, while long-term treatment is designed to improve vestibular compensation. Summary: VN is clearly defined as an important viral inner ear disorder.
Objectives: Our primary objective was to investigate the long-term usage of cochlear implants (CIs) in children who underwent sequential bilateral CI (SeqBCI), and to study factors that impact usage. Our secondary objective was to understand the difference in subjective benefit and educational/employment status, between users and non-users of the second CI (CI2). Study Design: Prospective case series. Setting: Tertiary academic centers. Patients: Sixty-eight young adults who underwent SeqBCI as children. Interventions: Pediatric SeqBCI. Main Outcome Measures: The main outcome measures were the current usage of the first CI (CI1) and CI2, factors that determine usage, current perceptions of their CIs, educational/employment status, and Speech, Spatial and Qualities of Hearing scale (SSQ12) scores. Results: Sixty five (95.6%) participants were using CI1 for over 8 h/d and the rest were using CI1 for 4 to 8 h/d. Fourty four (64.7%) participants used CI2 for at least 4 h/d, 10 (15%) indicated that they rarely used CI2 (<4 h/d) and 14 (21%) were not using CI2 at all. On multivariate analysis, the only independent predictor of long-term usage of CI2 was the inter-implant interval (odds ratio [OR] 0.78, standard deviation [SD] 0.65–0.91, p = 0.002). There was no significant difference in the SSQ12 scores of users and non-users of CI2. Conclusion: The finding of increasing rates of non-usage of CI2 with lengthening inter-implant interval is clinically relevant and critical to health-economic assessment. From a usage point of view, the evidence is sufficiently robust to recommend that in children with bilateral deafness, bilateral CI should be done simultaneously, and if not, soon after the first CI. In the context of a longer inter-implant interval, clinicians should weigh the marginal benefits of CI2 against the surgical risks vis-a-vis non-usage and bilateral vestibular hypofunction.
Knowledge of the cochlear implant array's precise position is important because of the correlation between electrode position and speech understanding. Several groups have provided recent image processing evidence to determine scalar translocation, angular insertion depth, and cochlear duct length (CDL); all of which are being used for patient-specific programming. Cone beam computed tomography (CBCT) is increasingly used in otology due to its superior resolution and low radiation dose. Our objectives are as followed: 1.Validate CBCT by measuring cochlear metrics, including basal turn diameter (A-value) and lateral wall cochlear duct length at different angular intervals and comparing it against microcomputed CT (uCT).2.Explore the relationship between measured lateral wall cochlear duct length at different angular intervals and insertion depth among 3 different length electrodes using CBCT.The study was performed using fixed human cadaveric temporal bones in a tertiary academic centre. Ten temporal bones were subjected to the standard facial recess approach for cochlear implantation and imaged by CBCT followed by uCT. Measurements were performed on a three-dimensional reconstructed model of the cochlea. Sequential insertion of 3 electrodes (Med-El Flex24, 28 and Soft) was then performed in 5 bones and reimaged by CBCT. Statistical analysis was performed using Pearson's correlation.There was good agreement between CBCT and uCT for cochlear metrics, validating the precision of CBCT against the current gold standard uCT in imaging. The A-value recorded by both modalities showed a high degree of linear correlation and did not differ by more than 0.23 mm in absolute values. For the measurement of lateral wall CDL at various points along the cochlea, there was a good correlation between both modalities at 360 deg and 720 deg (r = 0.85, p < 0.01 and r = 0.79, p < 0.01). The Flex24 electrode displayed consistent insertion depth across different bones.CBCT reliably performs cochlear metrics and measures electrode insertion depth. The low radiation dose, fast acquisition time, diminished metallic artifacts and portability of CBCT make it a valid option for imaging in cochlear implant surgery.
Currently available aortic bioprosthetic heart valves are all relatively suboptimal due to the constraints placed on leaflets by stenting. The constraints on the stenting mechanism may directly or indirectly cause turbulence in the orifice neighborhood, be nidi of tissue calcification, and impart transleaflet stress differentials. To address all these deficiencies, we undertook the development of a stentless porcine aortic bioprosthesis (SPAB). This study evaluates the hemodynamic performance and durability of this design in special chambers with near physiologic compliance. The results are compared to those shown by a stented porcine aortic bioprosthesis. The pressure measurements under steady flow conditions showed that the hemodynamic performance (including pressure gradient and effective orifice area) of SPAB is superior to that of its stented counterpart, especially in the smaller sizes. In addition, it is expected that this stentless design should minimize the mechanical stress to which the leaflets are subjected throughout the cardiac cycle, thus enhancing the durability of the bioprosthesis. In our accelerated durability study for up to 2 equivalent years, no valve failure has been observed. More in vitro studies under pulsatile flow conditions, including color Doppler flow visualization, are currently being conducted.
To determine whether transcranial electrical stimulation-induced facial motor-evoked potential (FMEP) monitoring of the facial nerve (FN) during vestibular schwannoma (VS) tumor resection can predict both immediate and 1 year postoperative FN functional outcome.Prospective consecutive non-comparative observational case series.Tertiary referral center.Facial function, immediate post operation and at 1 year using House-Brackmann (HB) grading scale.The study included 367 consecutive patients (men 178; women 189; age 13-81 years) monitored during primary sporadic VS microsurgery between November 2002 and April 2015. Neurofibromatosis type II, revision surgery, previous radiotherapy treatment, preoperative facial nerve weakness, and non-VS cases were excluded retrospectively during analysis of data. Data of facial function were missing from eight patients at 1 year and were excluded. The correlation between the final-to-baseline FMEP ratio and immediate and 1 year facial nerve function was examined.Using logistic regression model, the cut-off points of FMEP ratio were 0.62 (PPV 0.96) and 0.59 (PPV 0.98) which predicted satisfactory FN function (HB grades 1 or 2) immediately postoperative and at 1 year after surgery, respectively.Transcranial electrical stimulation FMEP is a valuable tool for monitoring facial nerve function during resection of vestibular schwannoma. Maintaining a FMEP event-to-baseline ratio of 60% or greater is predictive of satisfactory long-term FN function.
Objectives 1. Determine the feasibility and efficiency of local magnetic targeting delivery of gadolinium (Gad) contrast to the inner ear in rodents. 2. Assess any potential ototoxicity of magnetic targeting delivery of Gad in the inner ear. 3. Study the utility of magnetic targeting delivery of Gad to visualize and quantify endolymphatic hydrops (EH) in a transgenic mouse model. Study Design Controlled in vivo animal model study. Methods Paramagnetic Gad was locally delivered to the inner ear using the magnetic targeting technique in both rat and mouse models. Efficiency of contrast delivery was assessed using magnetic resonance imaging (MRI). Ototoxicity of Gad was examined with histology of the cochlea and functional audiological tests. The Phex mouse model was used to study EH, hearing loss, and balance dysfunction. Magnetic targeting delivery of Gad contrast was used in the Phex mouse model to visualize the effects of EH using MRI. Results Magnetic targeting improved the delivery of Gad to the inner ear and the technique was reproducible in both rat and mouse models. The delivery method did not result in microstructural damage or any significant hearing loss in a normal animal. Magnetic targeting of Gad in the Phex mouse model allowed detailed visualization and quantification of EH. Conclusion This study provided the first evidence of the effectiveness and efficiency of the local magnetic targeting delivery of gadolinium contrast to the inner ear and its application to the visualization and quantification of EH. Laryngoscope , 133:914–923, 2023
Background: Balloon dilation of the eustachian tube is a new therapeutic option for eustachian tube dysfunction. One of the limiting factors of wider adoption of this technique in many parts of the world is the high cost of the devices, in spite of regulatory approval of safety. Objective: Evaluate the performance and usability of standard less-expensive endovascular balloons for eustachian tube dilation in comparison to an approved device in a preclinical study. Study Design: Comparative cadaver feasibility study. Setting: University tertiary care facility. Methods: Ten eustachian tube dilations were performed with an approved eustachian tube dilation device. Ten other procedures were carried out with an endovascular balloon of similar dimensions. Cone beam computerized tomography was performed to evaluate the extent of dilation and possible damages. The lumen and mucosal lining were inspected endoscopically post-dilation. Volume measurements were compared before and after the procedure in both groups using contrast enhancement. Results: All 20 eustachian tube dilations were carried out successfully. No tissue damages could be identified on cone-beam computerized tomography or via endoscopic examination. There was a statistically significant difference of eustachian tube volumes between pre- and post-dilations, with no statistically significant difference between the devices. Conclusion: Eustachian tube dilation with a less costly endovascular balloon achieved similar results to an approved eustachian tube dilation device. No damages or any other safety concerns were identified in a cadaver study.
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