Geometrically accurate real-time volumetric visualization of the middle ear using optical coherence tomography.

We introduce a novel system for geometrically accurate, continuous, live, volumetric middle ear optical coherence tomography imaging over a 10.9mm×30∘×30∘ field of view (FOV) from a handheld imaging probe. The system employs a discretized spiral scanning (DC-SC) pattern to rapidly collect volumetric data and applies real-time scan conversion and lateral angular distortion correction to reduce geometric inaccuracies to below the system's lateral resolution over 92% of the FOV. We validate the geometric accuracy of the resulting images through comparison with co-registered micro-computed tomography (micro-CT) volumes of a phantom target and a cadaveric middle ear. The system's real-time volumetric imaging capabilities are assessed by imaging the ear of a healthy subject while performing dynamic pressurization of the middle ear in a Valsalva maneuver.

Transtympanic Visualization of Cochlear Implant Placement With Optical Coherence Tomography: A Pilot Study.

OBJECTIVE: This study aimed to evaluate the ability of transtympanic middle ear optical coherence tomography (ME-OCT) to assess placement of cochlear implants (CIs) in situ. PATIENT: A 72-year-old man with bilateral progressive heredodegenerative sensorineural hearing loss due to work-related noise exposure received a CI with a slim modiolar electrode for his right ear 3 months before his scheduled checkup. INTERVENTION: A custom-built swept source ME-OCT system (λo = 1550 nm, ∆λ = 40 nm) designed for transtympanic middle ear imaging was used to capture a series of two- and three-dimensional images of the patient's CI in situ. Separately, transtympanic OCT two-dimensional video imaging and three-dimensional imaging were used to visualize insertion and removal of a CI with a slim modiolar electrode in a human cadaveric temporal bone through a posterior tympanotomy. MAIN OUTCOME MEASURE: Images and video were analyzed qualitatively to determine the visibility of implant features under ME-OCT imaging and quantitatively to determine insertion depth of the CI. RESULTS: After implantation, the CI electrode could be readily visualized in the round window niche under transtympanic ME-OCT in both the patient and the temporal bone. In both cases, characteristic design features of the slim modiolar electrode allowed us to quantify the insertion depth from our images. CONCLUSIONS: ME-OCT could potentially be used in a clinic as a noninvasive, nonionizing means to confirm implant placement. This study shows that features of the CI electrode visible under ME-OCT can be used to quantify insertion depth in the postoperative ear.

The remaining obstacles for a totally implantable cochlear implant.

PURPOSE OF THE REVIEW: For years, the development of a totally implantable cochlear implant (TICI) has faced several technical challenges hindering any prototypes from reaching full commercialization. This article aims to review the necessary specifications for a viable TICI. An overview of the remaining challenges when designing TICIs will be provided, focusing on energy supply and implantable microphones. RECENT FINDINGS: The literature review highlights how research efforts to generate sufficient power to supply a fully implantable CI could take advantage of microelectromechanical systems (MEMS)-based energy harvesters incorporating piezoelectric materials. Using one of the various energy sources in the vicinity of the temporal bone would allow the development of a self-sufficient implant, overcoming the limitations of electrochemical batteries. Middle ear implantable microphones could also use similar fabrication techniques and transduction mechanisms to meet the sensor requirements for a TICI. SUMMARY: Recent breakthroughs in power supply using MEMS-based energy harvesting technologies and piezoelectric implantable microphones may make TICIs become a more practical reality in the foreseeable future. Once available, TICIs will have major impact on our patients' quality of life and may help to make hearing rehabilitation a more appealing option to a greater proportion of those who fulfill our candidacy criteria.

Optical Clearing Agents for Optical Imaging Through Cartilage Tympanoplasties: A Preclinical Feasibility Study.

HYPOTHESIS: Optical clearing agents (OCAs) can render cartilage tympanoplasty grafts sufficiently transparent to permit visualization of middle ear structures in an operated ear using optical coherence tomography (OCT) imaging. METHODS: Pieces of human tragal cartilage were treated with glycerol, a commonly used OCA. A reference reflector was imaged with OCT through the tympanoplasty as it cleared and the optical attenuation of the graft was measured. The reversibility of clearing and the dimensional changes associated with glycerol absorption were also measured. In a separate experiment, a human cadaveric temporal bone was prepared to simulate an ossiculoplasty surgery with cartilage replacement of the tympanic membrane. A partial ossicular replacement prosthesis (PORP) inserted in the ear was imaged with OCT through a 0.4mm cartilage graft optically cleared with glycerol. MAIN OUTCOME MEASURE: The optical attenuation of 0.4mm cartilage grafts decreased at 2.3+/-1.1 dB/min following treatment with glycerol, reaching a total decrease in attenuation of 13.6+/-5.9 dB after 7 minutes. The optical and dimensional effects of glycerol absorption were reversable following saline washout. In the temporal bone preparation, treatment of a cartilage graft with glycerol resulted in a 13 dB increase in signal-to-noise ratio and a 13 dB increase in contrast for visualizing the PORP through the graft with OCT. CONCLUSIONS: Optical clearing agents offer a potential pathway towards optical coherence tomography imaging of the middle ear in post-surgical ears with cartilage grafts.

Clinical efficiency and safety of the oticon medical neuro cochlear implant system: a multicenter prospective longitudinal study.

OBJECTIVE: This prospective longitudinal cohort study at six tertiary referral centers in Canada and Denmark describes the clinical efficiency and surgical safety of cochlear implantation with the Oticon Medical Neuro cochlear implant system, including the Neuro Zti implant, the EVO electrode array, and the Neuro One sound processor. METHODS: Patients were adult cochlear implant candidates with bilateral sensorineural hearing loss. RESULTS: The mean HINT scores in quiet pre-operatively and at 3, 6, and 12 months post-activation were 13%, 58%, 67%, and 72%, respectively, and in noise (+10 dB SNR) 13%, 46%, 53%, and 59%, respectively. The mean improvement from baseline to 6 months post-activation was 54% in quiet and 40% in noise. The surgical major complication incidence rate was 0% and the post-surgical major complication incidence rate (until 12 months post-activation) was 4%. There was no adverse event that was fatal, that required explantation, or that resulted in sound processor nonuse, and no implant failure. CONCLUSION: Cochlear implantation with the Oticon Medical Neuro system enables speech identification both in quiet and in noise and audiologic outcomes continue to improve in the year following activation. No substantial adverse events occurred during the surgical implantation procedure and during the 12 months post-activation.

Treatment of patients with glomus jugulare tumours (GJT) and its subjective effect on quality of life (QoL) measures.

Cerebellopontine angle (CPA) tumours account for 6-10% of intracranial tumours. The most common CPA tumours are vestibular schwannomas (VS), also known as acoustic neuromas, benign tumours of the vestibulocochlear nerve. Less common but symptomatic skull base lesions are glomus jugulare tumours (GJT), of which approximately 40% are identified as CPA tumours. Initial symptoms for GJT may include hearing loss and tinnitus and progress to various cranial nerve dysfunctions. Three well-accepted treatment modalities for such tumours include surgical resection, radiotherapy and/or conservative management employing serial MR or CT imaging. Patients' quality of life may be impacted by different treatment methods, so treatment decisions should be client centered.

Optical Coherence Tomography Doppler Vibrometry Measurement of Stapes Vibration in Patients With Stapes Fixation and Normal Controls.

HYPOTHESIS: Ears with otosclerotic stapes fixation will exhibit lower-than-normal levels of ossicular mobility as measured by Optical Coherence Tomography Doppler Vibrometry (OCT-DV). BACKGROUND: OCT-DV measures the vibration of middle ear structures in response to sound non-invasively through the intact tympanic membrane. This allows, in particular, direct measurement of the vibration at the lenticular process of the incus which is expected to be lower in patients with otosclerotic stapes fixation. METHODS: OCT-DV was performed on ears presumptively diagnosed with otosclerosis (n = 13) and a group of normal control ears (n = 42). Displacement was measured at the umbo and the lenticular process of the incus in response to 500 and 1000 Hz stimulus tones at 100 dBSPL. MAIN OUTCOME MEASURE: The ability to discriminate between groups was assessed using receiver operator characteristic analysis, with the main outcome measures being the area-under-curve (AUC) and the sensitivity and specificity. RESULTS: For the best condition tested (500 Hz at the incus), the AUC was 0.998 and discriminated the otosclerotic from normal ears with a sensitivity/specificity of 1.00/0.98. One anomalous patient with surgically confirmed stapes fixation exhibited hypermobility at the umbo, possibly due to a partial ossicular discontinuity. Despite the high umbo mobility, this patient's stapes fixation was correctly discriminated based on the measured incus vibration levels. CONCLUSIONS: OCT-DV is a promising tool for preoperatively assessing ossicular mobility non-invasively in the clinic. Our results suggest OCT-DV may also be useful in discriminating other ossicular pathologies that result in conductive hearing loss.

Quality of life related to symptomatic outcomes in patients with vestibular schwannomas: A Canadian Centre perspective.

Patients with vestibular schwannomas (VS) typically present with hearing loss and tinnitus as well as variable cranial nerve dysfunctions. Surgical resection, stereotactic radiotherapy and/or conservative management employing serial magnetic resonance or computed tomography imaging serve as the main treatment options. Quality of life (QoL) may be impacted by the extent of tumour burden and exacerbated or relieved by treatment. Subjective assessment and quality of life inventories provide valuable information in client centered approaches with important implications for treatment. The intention of QoL measurements affecting VS patients within a clinical setting is to facilitate discussions regarding treatment options and objectively evaluate patient- centered clinical outcomes in a naturalistic setting.

Long term follow-up demonstrating stability and patient satisfaction of minimally invasive punch technique for percutaneous bone anchored hearing devices.

OBJECTIVE: Minimally Invasive Ponto Surgery (MIPS) was recently described to facilitate the placement of percutaneous bone anchored hearing devices. As early adopters of this new procedure, we sought to perform a quality assurance project using our own small prospective cohort to justify this change in practice. We chose to examine device stability and to gauge our patients' perspective of the surgery and their overall satisfaction with the process. METHODS: A total of 12 adult patients who underwent MIPS between 2016 and 2017 with a minimum post-operative follow-up of 12 months were included in this study. A prospective MIPS research clinic was used to follow patients, assess the implant site soft tissue status and gather qualitative information through patient interviews and surveys. RESULTS: The mean (SD) soft tissue status score averages using the IPS Scale were low for inflammation 0.1 (0.1), pain 0.1 (0.1), skin height 0.2 (0.1) and total IPS score 0.4 (0.3) indicating minimal soft tissue changes. Patient experiences with MIPS were overwhelmingly positive in reports through the MIPS modified SSQ-8. All patients reported speedy recoveries and no long-term complications. There were zero device losses. CONCLUSION: The series presented in this paper represents the first MIPS cohort with long term follow-up to be published to date in North America. Our findings conclude both device stability and patient satisfaction with no loss of fixtures. Consequently, we have adopted MIPS as our procedure of choice for the placement of all percutaneous BAHDs.

Shared decision making and decisional conflict in the Management of Vestibular Schwannoma: a prospective cohort study.

BACKGROUND: Patients with vestibular schwannomas (VS) are faced with complex management decisions. Watchful waiting, surgical resection, and radiation are all viable options with associated risks and benefits. We sought to determine if patients with VS experience decisional conflict when deciding between surgery or non-surgical management, and factors influencing the degree of decisional conflict. METHODS: A prospective cohort study in two tertiary ambulatory skull-base clinics was performed. Patients with newly diagnosed or newly growing vestibular schwannomas were recruited. Patients were given a demographic form and the decisional conflict scale (DCS), a validated measure to assess the degree of uncertainty when making medical decisions. The degree of shared decision making (SDM) experienced by the patient and physician were assessed via the SDM-Q-10 and SDM-Q-Doc questionnaires, respectively. Non-parametric statistics were used. Questionnaires and demographic information were correlated with DCS using Spearman correlation coefficient and Mann-Whitney U. Logistic regression was performed to determine factors independently associated with DCS scores. RESULTS: Seventy-seven patients participated (55% female, aged 37-81 years); VS ranged in size from 2 mm-50 mm. Significant decisional conflict (DCS score 25 or greater) was experienced by 17 (22%) patients. Patients reported an average SDM-Q-10 score of 86, indicating highly perceived level of SDM. Physician and patient SDM scores were weakly correlated (p = 0.045, Spearman correlation coefficient 0.234). DCS scores were significantly negatively correlated with a decision to pursue surgery, presence of a trainee, and higher SDM-Q-10 score. DCS was higher with female gender. Using logistic regression, the SDM-Q-10 score was the only variable associated with significantly reduced DCS. CONCLUSIONS: About one fifth of patients deciding how to manage their vestibular schwannoma experienced a significant degree of decisional conflict. Involving the patients in the process through shared decision-making significantly reduced the degree of uncertainty patients experienced.

Direct cost comparison of minimally invasive punch technique versus traditional approaches for percutaneous bone anchored hearing devices.

BACKGROUND: Minimally Invasive Ponto Surgery (MIPS) was recently described as a new technique to facilitate the placement of percutaneous bone anchored hearing devices. The procedure has resulted in a simplification of the surgical steps and a dramatic reduction in surgical time while maintaining excellent patient outcomes. Given these developments, our group sought to move the procedure from the main operating suite where they have traditionally been performed. This study aims to test the null hypothesis that MIPS and open approaches have the same direct costs for the implantation of percutaneous bone anchored hearing devices in a Canadian public hospital setting. METHODS: A retrospective direct cost comparison of MIPS and open approaches for the implantation of bone conduction implants was conducted. Indirect and future costs were not included in the fiscal analysis. A simple cost comparison of the two approaches was made considering time, staff and equipment needs. All 12 operations were performed on adult patients from 2013 to 2016 by the same surgeon at a single hospital site. RESULTS: MIPS has a total mean reduction in cost of CAD$456.83 per operation from the hospital perspective when compared to open approaches. The average duration of the MIPS operation was 7 min, which is on average 61 min shorter compared with open approaches. CONCLUSION: The MIPS technique was more cost effective than traditional open approaches. This primarily reflects a direct consequence of a reduction in surgical time, with further contributions from reduced staffing and equipment costs. This simple, quick intervention proved to be feasible when performed outside the main operating room. A blister pack of required equipment could prove convenient and further reduce costs.

Face and content validity of a novel, web-based otoscopy simulator for medical education.

BACKGROUND: Despite the fact that otoscopy is a widely used and taught diagnostic tool during medical training, errors in diagnosis are common. Physical otoscopy simulators have high fidelity, but they can be expensive and only a limited number of students can use them at a given time. OBJECTIVES: 1) To develop a purely web-based otoscopy simulator that can easily be distributed to students over the internet. 2) To assess face and content validity of the simulator by surveying experts in otoscopy. METHODS: An otoscopy simulator, OtoTrain™, was developed at Western University using web-based programming and Unity 3D. Eleven experts from academic institutions in North America were recruited to test the simulator and respond to an online questionnaire. A 7-point Likert scale was used to answer questions related to face validity (realism of the simulator), content validity (expert evaluation of subject matter and test items), and applicability to medical training. RESULTS: The mean responses for the face validity, content validity, and applicability to medical training portions of the questionnaire were all ≤3, falling between the "Agree", "Mostly Agree", and "Strongly Agree" categories. The responses suggest good face and content validity of the simulator. Open-ended questions revealed that the primary drawbacks of the simulator were the lack of a haptic arm for force feedback, a need for increased focus on pneumatic otoscopy, and few rare disorders shown on otoscopy. CONCLUSION: OtoTrain™ is a novel, web-based otoscopy simulator that can be easily distributed and used by students on a variety of platforms. Initial face and content validity was encouraging, and a skills transference study is planned following further modifications and improvements to the simulator.

Hearing preservation in vestibular schwannoma management.

OBJECTIVE: To compare hearing preservation between stereotactic radiotherapy (SRT) and conservative treatment of patients with unilateral vestibular schwannoma. DATA SOURCES: Retrospective case series comparing hearing outcomes of patients with a unilateral vestibular schwannoma managed conservatively or with stereotactic radiotherapy in a tertiary care academic centre. PATIENTS: Tumor database patients with American Academy of Otolaryngology Head and Neck Surgery Class A or B hearing at the onset of study. Stereotactic radiotherapy patients were predominantly those who failed conservative management. INTERVENTIONS: Audiometric pure tone averages and speech discrimination scores as well as patient demographics, tumor location, size and growth were extracted. MAIN OUTCOME MEASURES: Hearing outcome measures were: 1) Hearing Preservation, i.e. no drop from Class A/B to Class C/D hearing, 2) Hearing Survival of Class A/B hearing in months, 3) Audiometric Pure Tone Averages, Difference between post-treatment and pre-treatment, and 4) Speech Discrimination Score Difference (pre-treatment-post treatment). Survival analysis and non-parametric tests were used for hearing outcome measures, with multiple covariates tested. RESULTS: Overall, serviceable hearing preservation among the 123 patients was 51%. The median hearing survival time was 46 months (mean 59 months). The Pure Tone averages and Speech Discrimination score differences were 16 dB and 82% respectively over a median follow-up time of 43 months. No significant difference was found between the conservative and SRT groups in any hearing outcome. Class A patients showed far better hearing survival than Class B patients. CONCLUSIONS: No significant difference was demonstrated as to measures of hearing outcomes between stereotactic radiotherapy and conservative management. Excellent existing hearing appears to be the best predictor of long term hearing survival in the cohort studied.

Preoperative headband assessment for semi-implantable bone conduction hearing devices in conductive hearing loss: is it useful or misleading?

OBJECTIVE: To establish whether preoperative assessment using a conventional, percutaneous bone conducting implant (pBCI) processor on a headband accurately represents postoperative performance of a semi-implantable BCI (siBCI). STUDY DESIGN: Retrospective case series. SETTING: Tertiary otology unit. PATIENTS: Five patients with chronic otitis media (implanted unilaterally) and one with bilateral congenital ossicular fixation (implanted bilaterally). INTERVENTION(S): Semi-implantable bone conduction hearing implant. MAIN OUTCOME MEASURE(S): Functional hearing gain; preoperative (headband) versus postoperative (aided) speech discrimination; unaided bone conduction (BC) versus postoperative (aided) soundfield threshold. RESULTS: Significant functional gain was seen at all frequencies (one-tailed t test p G 0.01; n = 7). There was a 50 dB improvement in median speech reception threshold (SRT) from 70 dB unaided to 20 dB aided. Compared to the preoperative BC, aided siBCI thresholds were worse at 0.5 kHz, but at frequencies from 1 to 6 kHz, the siBCI closely matched the bone curve ( p G 0.01). The siBCI performed better than both pBCI processors on a headband at 3 to 4 kHz, except 1 kHz ( p G 0.01). CONCLUSIONS: BC thresholds may be a better indicator of implant performance than headband assessment. Candidacy assessment for siBCI implantation that relies on headband testing with pBCI processors should be interpreted with caution because the headband may under-represent the implanted device. This seems to be especially true at 3 kHz and above and may make it difficult for surgeons to conduct accurate informed consent discussions with patients about the realistic anticipated outcomes and benefits of the procedure.

Presentation of atrial fibrillation following oral dexamethasone treatment in a NF2 patient.

Atrial fibrillation (A-fib) is the most common cardiac arrhythmia which is associated with an increased risk of mortality secondary to stroke and coronary artery disease. Intravenous glucocorticoid therapy (such as dexamethasone and hydrocortisone) is frequently used peri-operatively in patients undergoing cardiac surgery to prevent A-fib. Dexamethasone is also frequently used in patients with single or bilateral vestibular schwannomas (VS), to reduce tumor swelling both before and after radiation treatment. We describe a case of A-fib in a 50 year-old female patient with neurofibromatosis type 2 (NF-2), who was prescribed dexamethasone for post-radiation tumor edema.

A case of bilateral internal auditory canal osteomas.

Osteomas of the skull base are rare, benign, slowly progressing growths of dense cortical bone. Osteomas occurring in the internal auditory canal are extremely rare. These lesions have sometimes been linked with dizziness, sensorineural hearing loss, and/or tinnitus. Although there have been documented cases in which surgical excision has improved these symptoms, symptomatic relief is not always achieved with surgical management. Here we present, to the best of our knowledge, only the third reported case of bilateral osteomas of the internal auditory canal. An 82-year-old woman presented with an acute onset of vertigo without a history of trauma or ear infection. She reported two similar episodes occurring a few years earlier, with symptoms persisting for only a few days. Audiometry showed presbycusis. Computed tomography and magnetic resonance imaging identified bilateral internal auditory canal osteomas. The patient was treated conservatively, monitored, and had complete resolution of her symptoms.

Natural history of hearing deterioration in intracanalicular vestibular schwannoma.

BACKGROUND: Intracanalicular vestibular schwannomas have a range of treatment options that can preserve hearing: microsurgery, stereotactic radiotherapy, and conservative observation. OBJECTIVE: To evaluate the natural course of hearing deterioration during a period of conservative observation. METHODS: A retrospective case review was performed on 47 patients with a unilateral intracanalicular vestibular schwannoma. Evaluation of growth was monitored by repeat MRI scanning. Repeated pure-tone and speech audiometry results were evaluated for subgroups of patients showing growth or no growth and by subsite location of tumor in the internal auditory canal. RESULTS: Patients had a mean follow-up of 3.6 years. Over the entire population, the pure-tone average thresholds at 0.5, 1, 2, and 3 kHz and the word recognition scores both significantly deteriorated from 38 to 51 dB HL, and from 66% to 55%, respectively. Overall, 74% of subjects with good hearing, according to the 50/50 rule, maintained hearing above this rule. There were no significant differences in hearing loss by subsite in the internal auditory canal (porus, fundus, central) or by growth status (stable, growing, shrinking). Only 6 patients showed a large hearing change. This happened early during follow-up, with relatively stable hearing after this. CONCLUSION: Hearing will deteriorate in some intracanalicular vestibular schwannomas, regardless of tumor growth. Hearing deterioration, if on a large scale, most likely occurs early in follow-up. The present results using conservative management in these tumors appear similar to those reported for stereotactic radiotherapy or microsurgery.

Cochlear implant magnet extrusion with subsequent surgical replacement and restoration of full implant use without the need for device explantation.

OBJECTIVE AND IMPORTANCE: We recount the unusual case of a young boy whose removable cochlear implant magnet extruded through the skin after becoming displaced after several episodes of direct but minor head trauma. This article outlines a course of clinical management that resulted in the successful re-implantation of a new magnet without infective sequelae and the need for device explantation. CLINICAL PRESENTATION: The child presented with recurrent erythema and swelling at the implant site. In retrospect, subtle magnet displacement was not readily identified on initial imaging. The external magnet required an increase in strength while local swelling settled, but subsequently had to be reduced as the magnet was drawn gradually to the skin surface. Full extrusion took place, but in the absence of any obvious infection, the site healed quickly. INTERVENTION AND TECHNIQUE: The external device was retained with a self-adhesive disc for 1 year, during which time the patient was observed closely for signs of local infection. The child was subsequently admitted for surgical re-exploration and insertion of a new magnet. Care was taken to re-establish the integrity of the fibrous pocket that surrounded the cochlear implant. CONCLUSION: This uneventful intervention was followed by the resumption of full and unimpaired implant use. At the time of this article submission, the child is now 5 years post-extrusion and continues to do well in full-time education.

Over-expression of X-linked inhibitor of apoptosis protein slows presbycusis in C57BL/6J mice.

Apoptosis of cochlear cells plays a significant role in age-related hearing loss or presbycusis. In this study, we evaluated whether over-expression of the anti-apoptotic protein known as X-linked Inhibitor of Apoptosis Protein (XIAP) slows the development of presbycusis. We compared the age-related hearing loss between transgenic (TG) mice that over-express human XIAP tagged with 6-Myc (Myc-XIAP) on a pure C57BL/6J genetic background with wild-type (WT) littermates by measuring auditory brainstem responses. The result showed that TG mice developed hearing loss considerably more slowly than WT littermates, primarily within the high-frequency range. The average total hair cell loss was significantly less in TG mice than WT littermates. Although levels of Myc-XIAP in the ear remained constant at 2 and 14 months, there was a marked increase in the amount of endogenous XIAP from 2 to 14 months in the cochlea, but not in the brain, in both genotypes. These results suggest that XIAP over-expression reduces age-related hearing loss and hair cell death in the cochlea.