Tumor biomechanical stiffness by magnetic resonance elastography predicts surgical outcomes and identifies biomarkers in vestibular schwannoma and meningioma.

Variations in the biomechanical stiffness of brain tumors can not only influence the difficulty of surgical resection but also impact postoperative outcomes. In a prospective, single-blinded study, we utilize pre-operative magnetic resonance elastography (MRE) to predict the stiffness of intracranial tumors intraoperatively and assess the impact of increased tumor stiffness on clinical outcomes following microsurgical resection of vestibular schwannomas (VS) and meningiomas. MRE measurements significantly correlated with intraoperative tumor stiffness and baseline hearing status of VS patients. Additionally, MRE stiffness was elevated in patients that underwent sub-total tumor resection compared to gross total resection and those with worse postoperative facial nerve function. Furthermore, we identify tumor microenvironment biomarkers of increased stiffness, including αSMA + myogenic fibroblasts, CD163 + macrophages, and HABP (hyaluronic acid binding protein). In a human VS cell line, a dose-dependent upregulation of HAS1-3, enzymes responsible for hyaluronan synthesis, was observed following stimulation with TNFα, a proinflammatory cytokine present in VS. Taken together, MRE is an accurate, non-invasive predictor of tumor stiffness in VS and meningiomas. VS with increased stiffness portends worse preoperative hearing and poorer postoperative outcomes. Moreover, inflammation-mediated hyaluronan deposition may lead to increased stiffness.

Further Validity Evidence for Patient-Specific Virtual Reality Temporal Bone Surgical Simulation.

OBJECTIVE: Patient-specific virtual reality (VR) simulation of cochlear implant (CI) surgery potentially enables preoperative rehearsal and planning. We aim to gather supporting validity evidence for patient-specific simulation through the analysis of virtual performance and comparison with postoperative imaging. METHODS: Prospective, multi-institutional study. Pre- and postoperative cone-beam CT scans of CI surgical patients were obtained and processed for patient-specific VR simulation. The virtual performances of five trainees and four attendings were recorded and (1) compared with volumes removed during actual surgery as determined in postoperative imaging, and (2) assessed using the Copenhagen Cochlear Implant Surgery Assessment Tool (CISAT) by two blinded raters. The volumes compared were cortical mastoidectomy, facial recess, and round window (RW) cochleostomy as well as violation of the facial nerve and chorda. RESULTS: Trainees drilled more volume in the cortical mastoidectomy and facial recess, whereas attendings drilled more volume for the RW cochleostomy and made more violations. Except for the cochleostomy, attendings removed volumes closer to that determined in postoperative imaging. Trainees achieved a higher CISAT performance score compared with attendings (22.0 vs. 18.4 points) most likely due to lack of certain visual cues. CONCLUSION: We found that there were differences in performance of trainees and attendings in patient-specific VR simulation of CI surgery as assessed by raters and in comparison with actual drilled volumes. The presented approach of volume comparison is novel and might be used for further validation of patient-specific VR simulation before clinical implementation for preoperative rehearsal in temporal bone surgery. LEVEL OF EVIDENCE: n/a Laryngoscope, 134:1403-1409, 2024.

Noise-induced hearing loss in the contralateral ear during otologic and neurotologic surgeries.

OBJECTIVE: Noise-induced hearing loss in the non-surgical ear during otologic/neurotologic surgery has not been well studied. The purpose of this study was to evaluate changes in hearing that may occur in the contralateral (i.e., non-surgical) ear after various otologic/neurotologic surgeries due to noise generated by drills. We hypothesized that otologic/neurotologic surgeries, longer in duration, would suggest longer drilling times and result in decreased hearing in the contralateral ear as evidenced by a change post-operative pure tone air conduction thresholds when compared to pre-operative thresholds. METHODS: A retrospective chart review at a tertiary referral center. Adult patients (18-75 years old) who underwent otologic/neurotologic surgeries from May 1, 2016 through May 1, 2021 were considered for inclusion. Surgeries included vestibular schwannoma resection (translabyrinthine, middle cranial fossa, or retrosigmoid approaches), endolymphatic sac/shunt and labyrinthectomy for Meniere's disease, and tympanomastoid surgery for middle ear pathology (e.g., cholesteatoma). Patient characteristics obtained through record review included age, sex, surgical procedure, pre-operative and post-operative audiometric thresholds and word recognition scores (WRS) for the contralateral ear, and duration of surgery. RESULTS: No significant differences were observed for change in audiometric thresholds in the contralateral ear for any surgery when considering individual frequencies. Additionally, no significant change in WRS was observed for any surgical approach. CONCLUSIONS: The risk of hearing loss in the non-surgical ear during various otologic/neurotologic surgeries appears to be minimal when measured via routine clinical tests.

Post-operative evaluation of computed tomography imaging following cochlear implantation.

PURPOSE: This study utilized an automated segmentation algorithm to assess the cochlear implant electrode array within the cochlea and investigate its impact on audiologic outcomes as measured by post-operative speech perception scores. Furthermore, manual evaluations of electrode placement were compared to automatic segmentation methods to determine their accuracy in predicting post-operative audiologic outcomes. MATERIALS AND METHODS: This retrospective chart review was conducted at a tertiary care referral center involving adult post-lingually deafened cochlear implant recipients implanted from 2015 to 2019. Patients with appropriate postoperative imaging and speech testing were included. Patients were excluded if non-English speaking, had a cognitive deficit, or a labyrinthine malformation. Automated and manual methods were used to analyze computed tomography (CT) scans and correlate the findings with post-operative speech perception scores and detection of electrode translocation. RESULTS: Among the 47 patients who met inclusion criteria, 15 had electrode translocations confirmed by automatic segmentation methods. Controlling for CI usage and pre-operative AzBio scores, patients with translocation exhibited significantly lower consonant-nucleus consonant (CNC) and AzBio scores at 6-months post-implantation compared to patients with ST insertions. Moreover, the number of translocated electrode contacts was significantly associated with post-operative CNC scores. Manual evaluations of electrode location were predictive but less sensitive to electrode translocations when compared with automated 3D segmentation. CONCLUSIONS: Placement of CI electrode contacts within ST without translocation into SV, leads to improved audiologic outcomes. Manual assessment of electrode placement via temporal bone CT, without 3D reconstruction, provides a less sensitive method to determine electrode placement than automated methods. LEVEL OF EVIDENCE: Level 4. LAY SUMMARY: This study investigated the impact of electrode placement on speech outcomes for cochlear implant recipients. Using advanced imaging techniques, the researchers compared automated and manual methods for evaluating electrode position and examined the relationship between electrode translocation and audiologic outcomes. The findings revealed that proper placement within the cochlea without translocation into inappropriate compartments inside the cochlea improves speech understanding. Manual evaluations were somewhat accurate but less sensitive in detecting translocations compared to automated methods, which offer more precise predictions of patient outcomes. These results contribute to our understanding of factors influencing cochlear implant success and highlight the importance of optimizing electrode placement for improved speech outcomes.

Noise-Vocoded Sentence Recognition and the Use of Context in Older and Younger Adult Listeners.

PURPOSE: When listening to speech under adverse conditions, older adults, even with "age-normal" hearing, face challenges that may lead to poorer speech recognition than their younger peers. Older listeners generally demonstrate poorer suprathreshold auditory processing along with aging-related declines in neurocognitive functioning that may impair their ability to compensate using "top-down" cognitive-linguistic functions. This study explored top-down processing in older and younger adult listeners, specifically the use of semantic context during noise-vocoded sentence recognition. METHOD: Eighty-four adults with age-normal hearing (45 young normal-hearing [YNH] and 39 older normal-hearing [ONH] adults) participated. Participants were tested for recognition accuracy for two sets of noise-vocoded sentence materials: one that was semantically meaningful and the other that was syntactically appropriate but semantically anomalous. Participants were also tested for hearing ability and for neurocognitive functioning to assess working memory capacity, speed of lexical access, inhibitory control, and nonverbal fluid reasoning, as well as vocabulary knowledge. RESULTS: The ONH and YNH listeners made use of semantic context to a similar extent. Nonverbal reasoning predicted recognition of both meaningful and anomalous sentences, whereas pure-tone average contributed additionally to anomalous sentence recognition. None of the hearing, neurocognitive, or language measures significantly predicted the amount of context gain, computed as the difference score between meaningful and anomalous sentence recognition. However, exploratory cluster analyses demonstrated four listener profiles and suggested that individuals may vary in the strategies used to recognize speech under adverse listening conditions. CONCLUSIONS: Older and younger listeners made use of sentence context to similar degrees. Nonverbal reasoning was found to be a contributor to noise-vocoded sentence recognition. However, different listeners may approach the problem of recognizing meaningful speech under adverse conditions using different strategies based on their hearing, neurocognitive, and language profiles. These findings provide support for the complexity of bottom-up and top-down interactions during speech recognition under adverse listening conditions.

Lack of neural contributions to the summating potential in humans with Meniere's disease.

Objective: To investigate the electrophysiology of the cochlear summating potential (SP) in patients with Meniere's disease (MD). Although long considered a purely hair cell potential, recent studies show a neural contribution to the SP. Patients with MD have an enhanced SP compared to those without the disease. Consequently, this study was to determine if the enhancement of the SP was in whole or part due to neural dysfunction. Design: Study participants included 41 adults with MD and 53 subjects with auditory neuropathy spectrum disorder (ANSD), undergoing surgery where the round window was accessible. ANSD is a condition with known neural dysfunction, and thus represents a control group for the study. The ANSD subjects and 17 of the MD subjects were undergoing cochlear implantation (CI) surgery; the remaining MD subjects were undergoing either endolymphatic sac decompression or labyrinthectomy to alleviate the symptoms of MD. Electrocochleography was recorded from the round window using high intensity (90 dB nHL) tone bursts. The SP and compound action potential (CAP) were measured to high frequencies (> = 2 kHz) and the SP, cochlear microphonic (CM) and auditory nerve neurophonic (ANN) to low frequencies. Linear mixed models were used to assess differences between MD and ANSD subjects. Results: Across frequencies, the MD subjects had smaller alternating current (AC) response than the ANSD subjects (F = 31.61,534, p < 0.001), but the SP magnitudes were larger (F = 94.31,534, p < 0.001). For frequencies less than 4 kHz the SP magnitude in the MD group was significantly correlated with the magnitude of the CM (p's < 0.001) but not in the ANSD group (p's > 0.05). Finally, the relative proportions of both ANN and CAP were greater in MD compared to ANSD subjects. The shapes of the waveforms in the MD subjects showed the presence of multiple components contributing to the SP, including outer and inner hair cells and neural activity. Conclusion: The results support the view that the increased negative polarity SP in MD subjects is due to a change in the operating point of hair cells rather than a loss of neural contribution. The steady-state SP to tones in human subjects is a mixture of different sources with different polarities.

Development of a novel screening tool for predicting Cochlear implant candidacy.

OBJECTIVES: Cochlear implantation (CI) is a well-established treatment for sensorineural hearing loss. Due in part to a lack of referral guidelines, CI technology remains underutilized, and many patients who could benefit from CI may not be referred for evaluation. This study aimed to develop a model for predicting CI candidacy using routine audiometric measures, with the goal of providing guidance to clinicians regarding when to refer a patient for CI evaluation. METHODS: Unaided three-frequency pure tone average (PTA), unaided speech discrimination score (SDS), and best-aided sentence recognition testing with AZBio sentence lists were collected from 252 subjects undergoing CIE. Candidacy was defined by meeting traditional (AZBio score ≤ 60%), or Medicare criteria (≤40%). A logistic regression model was developed to predict candidacy. Confusion matrices were plotted to determine the sensitivity and specificity at various probability thresholds. RESULTS: Logistic regression models were capable of predicting probability of candidacy for traditional criteria (P < .001) and Medicare criteria (P < .001). PTA and SDS were significant predictors (P < .001). Using a probability cutoff of .5, the models yielded a sensitivity rate of 91% and 78% for traditional and Medicare criteria, respectively. CONCLUSION: Probability of CI candidacy may be determined using a novel screening tool for referral. This tool supports individualized counseling, serves as a proof of concept for candidacy prediction, and could be modified based on an institution's philosophy regarding an acceptable false positive rate of referral. LEVEL OF EVIDENCE: 4.

Transformation from Sinonasal Seromucinous Hamartoma to Adenocarcinoma: A Case Report.

OBJECTIVES: Sinonasal hamartomas are benign neoplasms composed of disorganized mature tissue elements. Epithelial variants include respiratory epithelial adenomatoid hamartoma (REAH) and seromucinous hamartoma (SMH). Malignant transformation of REAH is rarely reported; however, the malignant transformation of SMH to adenocarcinoma has not been described. We report the first case of a transformation from SMH to adenocarcinoma. METHODS: The medical records of a patient presenting with sinonasal SMH with malignant transformation to adenocarcinoma were reviewed. The NCBI database was queried for the literature regarding SMH and malignant transformation of sinonasal hamartomas. RESULTS: A 39-year-old man presented with a left nasal mass, nasal obstruction, and epistaxis. Computed tomography and magnetic resonance imaging demonstrated a nonaggressive and heterogeneous left nasal mass with involvement of the middle turbinate and posterior ethmoid sinuses. He underwent endoscopic sinus surgery with complete excision of the mass. Pathology revealed SMH with focal areas of transition to low-grade adenocarcinoma characterized by stromal invasion but no bony, perineural, or lymphovascular invasion. Adjuvant treatment was not recommended. Literature review revealed no reported cases of malignant transformation of SMH. CONCLUSION: We report the first case of malignant transformation of SMH. Patients with SMH must be counseled that there is an extremely rare and potentially unrecognized risk of malignancy that may influence treatment and postoperative monitoring.

Early pediatric Cochlear implantation: An update.

The criteria and candidacy for pediatric cochlear implantation (CI) has significantly transformed over the past few decades and continues to evolve with technological advancements, and recognition of benefit in more diverse populations. Prolonged auditory deprivation among patients with profound sensorineural hearing loss has been shown to cause widespread degeneration in the central auditory system. Thus, there is increasing evidence advocating for earlier implantation within a critical neuroplastic window. However, there is a lack of consensus on this optimal age of implantation. Historically, there were concerns regarding surgical feasibility and safety, anesthesia risk, and logistical considerations in very young infants <12 months. Recent literature has investigated surgical safety and anesthesia risk as well speech and language outcomes with early implantation, resulting in the long-awaited reduction in approved age by the FDA (<9 months for certain devices). This article reviews logistical considerations, surgical safety, anesthesia risk, and language developmental outcomes associated with early CI (<12 months).

Patient-specific Virtual Temporal Bone Simulation Based on Clinical Cone-beam Computed Tomography.

OBJECTIVES: Patient-specific surgical simulation allows presurgical planning through three-dimensional (3D) visualization and virtual rehearsal. Virtual reality simulation for otologic surgery can be based on high-resolution cone-beam computed tomography (CBCT). This study aimed to evaluate clinicians' experience with patient-specific simulation of mastoid surgery. METHODS: Prospective, multi-institutional study. Preoperative temporal bone CBCT scans of patients undergoing cochlear implantation (CI) were retrospectively obtained. Automated processing and segmentation routines were used. Otologic surgeons performed a complete mastoidectomy with facial recess approach on the patient-specific virtual cases in the institution's temporal bone simulator. Participants completed surveys regarding the perceived accuracy and utility of the simulation. RESULTS: Twenty-two clinical CBCTs were obtained. Four attending otologic surgeons and 5 otolaryngology trainees enrolled in the study. The mean number of simulations completed by each participant was 16.5 (range 3-22). "Overall experience" and "usefulness for presurgical planning" were rated as "good," "very good," or "excellent" in 84.6% and 71.6% of the simulations, respectively. In 10.7% of simulations, the surgeon reported to have gained a significantly greater understanding of the patient's anatomy compared to standard imaging. Participants were able to better appreciate subtle anatomic findings after using the simulator for 60.4% of cases. Variable CBCT acquisition quality was the most reported limitation. CONCLUSION: Patient-specific simulation using preoperative CBCT is feasible and may provide valuable insights prior to otologic surgery. Establishing a CBCT acquisition protocol that allows for consistent segmentation will be essential for reliable surgical simulation. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:1855-1862, 2021.

Airway management protocol for conjoined twins delivery.

OBJECTIVE: Conjoined twin deliveries require collaborative preparation by multiple specialties for successful airway management. Literature regarding neonatal airway management after conjoined twin delivery is limited to case reports. We present a case series of conjoined twins and introduce an airway management protocol for conjoined twin delivery. METHODS: The medical records of conjoined twins and their mothers at a tertiary care center were reviewed from April 2016 to December 2018. The NCBI database was queried for literature regarding preparation for neonatal airway management after conjoined twins delivery. RESULTS: Five sets of conjoined twins were delivered. Of 10 neonates, all required bag valve mask ventilation. Other airway interventions included continuous positive airway pressure (7), endotracheal intubation (6), and direct laryngoscopy with telescopic video evaluation (1). No patients required ex-utero intrapartum treatment or emergent tracheostomy. A protocol for airway management is described and special considerations are discussed, including anatomic variations, equipment list, operating room staffing and layout, multidisciplinary prenatal conference, and airway imaging review. CONCLUSION: Conjoined twin deliveries have significant implications for the otolaryngologist and require multidisciplinary collaboration. An airway management protocol allows for a standardized process to secure the neonatal airway and optimize patient outcomes.

Evolving Criteria for Adult and Pediatric Cochlear Implantation.

The indications for cochlear implantation have gradually expanded as advancements in technology have evolved, resulting in improved audiologic outcomes for both adult and children. There remains a significant underutilization of cochlear implant technology in the United States, and recognition of the potential benefits of cochlear implantation for non-traditional indications is critical for encouraging the evolution of candidacy criteria. Adult cochlear implantation candidacy has progressed from patients with bilateral profound sensorineural hearing loss (SNHL) to include patients with greater degrees of residual hearing, single-sided deafness and asymmetric hearing, and atypical etiologies of hearing loss (eg, vestibular schwannoma, Ménière's disease, and otosclerosis). Indications for pediatric cochlear implantation have similarly evolved from children with bilateral severe to profound SNHL to implanting children at a younger age, including those with residual hearing, asymmetric hearing loss, inner ear malformations, as well as cochlear nerve deficiency. In this editorial, the literature investigating cochlear implantation for nontraditional indications is reviewed with an aim to use the best available evidence to encourage the evolution of candidacy criteria.

Autoimmune inner ear disease: A systematic review of management.

OBJECTIVES: The study systematically reviewed the existing literature on the management of autoimmune inner ear disease (AIED). STUDY DESIGN: Systematic review. METHODS: We performed a literature search of Embase, NCBI, Cochrane, and Web of Science databases from April 1990 to April 2020. Inclusion criteria included studies that were retrospective or prospective in nature evaluating the treatment of AIED with audiometric data measuring hearing outcomes during treatment. Hearing improvement was the primary study outcome and improvement in vestibular symptoms was the secondary study outcome. RESULTS: Sixteen of 412 candidate articles were included in our study. Systemic steroid treatment is most commonly described. Alternative treatment modalities included intratympanic steroid treatment, methotrexate, cyclophosphamide, azathioprine, infliximab, etanercept, adalimumab, golimumab, methylprednisolone, rituximab, and anakinra. CONCLUSION: Systemic corticosteroids are the first line treatment of AIED. Intratympanic steroids are a potential adjuvant or alternative treatment for patients who cannot tolerate or become refractory to steroid treatment. Steroid nonresponders may benefit from biologic therapy. Alternative treatment modalities including nonsteroidal immunosuppressants and biologics have been studied in small cohorts of patients with varying results. Prospective studies investigating the efficacy of biologic and nonsteroidal therapy are warranted. LEVEL OF EVIDENCE: 2.

Prevalence of occult cochlear basal turn patency.

BACKGROUND: Perilymph gusher (PLG) is a rare complication of otologic surgery attributed to a communication between the cochlea and the internal auditory canal (IAC). Subtle patency between the cochlear basal turn and IAC has recently been identified on computed tomography (CT) as a risk factor, specifically when the defect is > 0.75 mm. OBJECTIVES: Investigate the prevalence of radiographic cochlear basal turn patency. MATERIALS AND METHODS: Patients with CT of the temporal bones and inner ears interpreted as "normal" were included. An otologist and a radiologist independently reviewed CTs to measure radiographic dehiscence in an oblique plane along the interface of the cochlea and IAC. Known PLGs were excluded. RESULTS: Two hundred and ten ears were included (88 conductive or mixed hearing loss, 62 sensorineural hearing loss, 41 audiometrically normal ears). 71 ears (33.8%) were radiographically patent. Mean defect width was 0.41 mm (0.15-0.7 mm). Defect width was not associated with type of hearing loss, age, or gender. No defects were wider than 0.75 mm. CONCLUSIONS: Radiographic patency of the cochlear basal turn may be present in patients with hearing loss and normal hearing, but patency > 0.75 mm (i.e. risk for PLG) is rare.

Intraoperative Electrocochleography of Posterior Fossa Tumors Producing Menière's Syndrome.

OBJECTIVES: Intraoperative electrocochleography (ECochG) has provided insight regarding inner ear pathophysiology during neurotologic procedures. In this study, intraoperative ECochG findings are reported in patients who presented with episodic aural and vestibular symptoms during resection of posterior fossa neoplasms. PATIENTS: Three patients with episodic vertigo who underwent resection of posterior fossa tumors. INTERVENTION: Intraoperative ECochG was performed before and after tumor resection with the active electrode at the round window. Acoustic stimuli consisted of click and tone bursts presented in alternating polarity. MAIN OUTCOME MEASURE: ECochG responses including summation potential (SP), action potential (AP), and SP:AP ratio values to evaluate for endolymphatic hydrops. RESULTS: All subjects presented with asymmetric sensorineural hearing loss (SNHL), episodic vertigo, and tinnitus. Subject 1 was a 63-year-old woman who underwent left translabyrinthine excision of an endolymphatic sac (ELS) tumor and demonstrated no measurable responses until fenestration of the lateral semicircular canal, suggesting severe hydrops relieved by labyrinthotomy. Subject 2 was a 44-year-old woman who underwent right ELS tumor resection and exhibited an elevated SP:AP ratio. Subject 3 was a 55-year-old woman who underwent right retrolabyrinthine resection of a meningioma and exhibited robust responses without hydrops. CONCLUSIONS: Endolymphatic hydrops secondary to mechanical obstruction by a posterior fossa neoplasm may be demonstrated using intraoperative ECochG. Immediate improvement of hydrops may not be demonstrated after tumor resection.

Enlarged vestibular aqueduct: Intraoperative electrocochleography findings during cochlear implantation.

Enlarged vestibular aqueduct (EVA) is the most frequent inner ear abnormality found on computed tomography in children with sensorineural hearing loss. The effects EVA abnormalities have on electrocochleography (ECochG) are unknown. Positive deflections in summation potential evoked by tone bursts were observed in 3/5 subjects, while a large negative deflection, similar to endolymphatic hydrops (EH), was observed for 2/5 subjects. The presence of an enlarged summation potential, with and without a compound action potential, was observed in response to a broadband click stimulus. Results suggest likely effects of a third window on ECochG responses and presence of EH in EVA.

Utilizing Electrocochleography as a Microphone for Fully Implantable Cochlear Implants.

Current cochlear implants (CIs) are semi-implantable devices with an externally worn sound processor that hosts the microphone and sound processor. A fully implantable device, however, would ultimately be desirable as it would be of great benefit to recipients. While some prototypes have been designed and used in a few select cases, one main stumbling block is the sound input. Specifically, subdermal implantable microphone technology has been poised with physiologic issues such as sound distortion and signal attenuation under the skin. Here we propose an alternative method that utilizes a physiologic response composed of an electrical field generated by the sensory cells of the inner ear to serve as a sound source microphone for fully implantable hearing technology such as CIs. Electrophysiological results obtained from 14 participants (adult and pediatric) document the feasibility of capturing speech properties within the electrocochleography (ECochG) response. Degradation of formant properties of the stimuli /da/ and /ba/ are evaluated across various degrees of hearing loss. Preliminary results suggest proof-of-concept of using the ECochG response as a microphone is feasible to capture vital properties of speech. However, further signal processing refinement is needed in addition to utilization of an intracochlear recording location to likely improve signal fidelity.