bluuebunny/crossref_metadata_2025_split huggingface dataset:
Forces and Trauma Associated with Minimally‐Invasive, Image‐Guided Cochlear Implantation
Authors: Rohani Pooyan , Pile Jason , Kahrs Lueder , Balachandran Ramya , Blachon Gregoire , Simaan Nabil , Labadie Robert F. 
Published: August 2013

Objectives:Minimally‐invasive, image‐guided cochlear implantation (CI) uses a patient‐customized microstereotactic frame to access the cochlea via a single drill‐pass. We investigated the average force and trauma associated with the insertion of lateral wall CI electrodes using this technique.Methods:Microstereotactic frames for 6 fresh cadaveric temporal bones were built using computed tomography (CT) scans to determine an optimal drill path, following which drilling was performed. A tympanomeatal flap was raised, the round window (RW) overhang was taken down, and the RW membrane was reflected posteriorly. CI electrodes were inserted using surgical forceps to manually advance the CI electrode array, via the drilled tunnel, into the cochlea. Forces were recorded using a 6‐axis load sensor placed under the temporal bone during insertion of lateral wall electrode arrays (2 each of Nucleus CI422, MED‐EL standard, and MED‐EL standard with stiffeners). Tissue histology was performed by removing the lateral wall of the cochlea allowing photo‐documentation of electrode position and microscopic assessment of intracochlear tissue.Results:After drilling, CT scanning demonstrated successful access to cochleae in all 6 bones. Average insertion forces were 0.0088‐0.0780N. Peak forces were 0.0564‐0.4688N. Single factor analysis of variance was not statistically significant comparing average forces of different electrodes (P = 0.77). Tissue histology showed complete scala tympani insertion in all specimens with depth of insertion ranging from 360‐600°. No intracochlear trauma was identified.Conclusions:In this cadaver model with a minimally‐invasive, image‐guided CI approach, the use of lateral wall electrodes was associated with insertion forces comparable to traditional CI surgery. Deep insertions were obtained without identifiable trauma.
Heptanol Application to the Mouse Round Window: A Novel Model for Studying Cochlear Regenerative Potential
Authors: Stevens Shawn M. , Xing Yazhi , Hao Xinping , Zhu Juhong , Hensley Christopher , Lang Hainan 
Published: August 2013

Objectives:1) Introduce a novel model for studying cochlear lateral wall regeneration. 2) Describe implications of this study on research and treatment of human presbycusis. Background: Human presbycusis likely occurs secondary to senile degeneration of the stria vascularis (SV) and spiral ligament fibrocytes (SLFs). SLFs have a limited regenerative capacity. Augmenting this process may play a role in hearing preservation, recovery, or both. Few models currently exist, however, that can selectively and temporarily damage the cochlear lateral wall to study SLF regeneration.Methods:Heptanol, a gap junction uncoupler, was surgically applied to the round window of 25 normal hearing mice, with sacrifice at points 12 hours ‐ 14 days post‐treatment. Auditory brainstem response testing, electron microscopy, and immunostaining techniques were used to assess treatment response.Results:Click tone thresholds were significantly elevated (mean +40.5 dB sound pressure level) in all treated mice. Hearing loss plateaued on days 1‐7, followed by near complete recovery thereafter. Ultrastructural analysis revealed selective SV injury and SLF apoptosis at the apical, middle, and basal turns. A marked reduction in ion channel immunostaining intensity occurred throughout the lateral wall but resolved by 2 weeks. 3‐4 days, SLFs stained positive for EdU, a labeled thymidine analog and marker of cellular proliferation.Conclusions:This is one of the first models described to reliably and selectively induce lateral wall toxicity followed by full hearing recovery and SLF regeneration. Future study of the molecular and genetic expression profiles governing this process will be greatly facilitated by this technique.
High‐Resolution Microendoscope Images of Middle Ear Cholesteatoma and Surrounding Tissue: Evaluation of Interobserver Concordance
Authors: Bradley James A. , Jiang Nancy , Levy Lauren L. , Richards‐Kortum Rebecca , Sikora Andrew , Smouha Eric E. 
Published: August 2013

Objectives:High‐resolution microendoscopy (HRME) has great potential to detect residual cholesteatoma in patients. This study investigated how accurately otolaryngologists could differentiate between images obtained with HRME of ex vivo cholesteatoma specimens and surrounding middle ear epithelium.Methods:Cholesteatoma and surrounding middle ear epithelium were resected from patients. Tissues were stained with a contrast agent, proflavine. The HRME was placed directly on each specimen, and images were captured. Specimens were sent for standard histopathology and were subsequently compared with HRME images. Images were evaluated for quality control, and a training set was assembled. After viewing training images, 8 otolaryngologists without prior cholesteatoma HRME experience reviewed and classified test images.Results:Ten cholesteatoma and 9 middle ear specimens were collected, of which 17 representative cholesteatoma and 19 middle ear epithelium images were extracted for a testing set. Qualitative analysis for concordance between HRME images and histological images yielded a strong correlation between modalities. The mean accuracy of all reviewers in correctly identifying images was 95% [95% confidence interval [CI]: 92, 98]. The sensitivity to correctly detect cholesteatoma images was 98% [95% CI: 93, 100], and the specificity was 92% [95% CI: 87, 97]. The Fleiss kappa inter‐rater reliability score was 0.83 [95% CI: 0.77, 0.89].Conclusions:Medical professionals can quickly be trained to accurately distinguish between HRME images of cholesteatoma and normal middle ear epithelium, both of which have distinct imaging characteristics. Real‐time HRME optical imaging can potentially improve the results of otologic surgery by allowing for extirpation of cholesteatomas while eliminating residual disease.
Introducing the Tibial‐Dorsalis Pedis Osteocutaneous Shin Flap: A New Option for Oromandibular Reconstruction
Authors: Chandler Ashley R. , Tanna Neil , Costantino Peter D. , Boyd J. Brian , Mulholland R. Stephen 
Published: August 2013

Objectives:The authors investigate the possibility of incorporating a well vascularized, partial corticotomy of the anterolateral aspect of the tibia in‐series with a dorsalis pedis fasciocutaneous free flap for oromandibular reconstruction.Methods:The study consisted of three components. A cadaveric perfusion study was performed to characterize the vascular territory of the anterior tibial artery in regard to the surrounding osseous and soft tissue. A two‐point breaking strength of the tibia was examined with fracture strain gauge analysis to determine the threshold of tibia corticotomy that would lead to a pathological fracture. Finally, the authors performed an in‐vivo prospective clinical examination of the tibial‐dorsalis pedis osteocutaneous shin flap.Results:The perfusion study revealed that the anterior tibial artery provided a rich matrix of myofascial periosteal blood supply to the anterolateral cortex of the tibia that could support free osseous tibial transfer. Two‐point osteotomy fracture strain gauge analysis demonstrated that the threshold of tibia corticotomy that would lead to fracture of the remaining tibia was 30%. The osteocutaneous shin flap was performed in eight patients for recurrent, radiation failure, oral cavity T4 squamous cell carcinomas. The mean follow‐up was 61 months. There were no cases of flap loss, salivary fistula, nonunion, or tibia pathologic fracture. All patients achieved ambulation.Conclusions:The authors introduce the osteocutaneous tibial‐dorsalis pedis free vascularized flap as a viable option for oromandibular reconstruction. Its most notable advantage is the independent mobility of the skin paddle, in combination with an osseous reconstruction of the mandibular arch that facilitates primary osseointegration or denture rehabilitation.
Idiopathic Sudden Sensorineural Hearing Loss: Vascular or Viral?
Authors: Linthicum Frederick H. , Doherty Joni K. , Berliner Karen I. 
Published: August 2013

Objectives:Idiopathic unilateral sudden sensorineural hearing loss (ISSNHL) has been debated to arise from either a vascular or viral etiology. Recent studies citing evidence of a vascular etiology have been correlational in design without examination of histopathological data. It has been well established that vascular compromise results in fibrosis and/or neo‐osteogenesis within the scala tympani of the cochlea. Conversely, sudden hearing loss due to viral infections, such as measles and mumps, has been demonstrated to lead to degeneration of the stria vascularis, organ of Corti, and tectorial membrane. Abundant other research has indicated a probable viral etiology, including cochlear nerve enhancement on magnetic resonance imaging, suggesting an inflammatory process.Methods:A retrospective case review including clinical history, audiometry, and temporal bone histopathology of 7 temporal bones with known vascular impairment due to surgical intervention was compared to that of 11 bones with a history of ISSNHL with attention to the spiral ligament, stria vascularis, organ of Corti hair cells, tectorial membrane, ganglion cell population, and degree of perilymph fibrosis and/or neo‐osteogenesis.Results:Compared to 6 out of 7 vascular cases (86%) with fibrosis (P ≤. 001), ISSNHL cases exhibited more widespread tectorial membrane abnormalities, no perilymph fibrosis, less loss of ganglion cells (P ≤. 035), greater survival of spiral ligament (P ≤. 029), and twice the survival of hair cells on average.Conclusions:Analysis of human temporal bones from patients with sudden sensorineural hearing loss does not support a vascular insufficiency but rather suggests a viral etiology.
Impact of Immediate Postlateral Skull Base Surgery CT Scans on Clinical Management
Authors: Jiang Zi Y. , Allen Kyle P. , Isaacson Brandon 
Published: August 2013

Objectives:Determine the frequency of abnormalities on immediate (<24 hours) postoperative CT scans for lateral skull base surgical patients and the impact of abnormalities found on postoperative management.Methods:Study Design: case series with chart review. Setting: inpatient tertiary care hospital. Adult patients undergoing lateral skull base surgery were identified using a CPT code search from September 2011 to December 2012. Patient demographics, type of skull base lesion, surgical approach, length of operation, time between end of the surgery and computed tomography (CT) scan, CT scan findings, and patient post‐surgical neurologic status were collected.Results:Sixty‐two patients were identified (mean age 48, 50% male). 32 patients had schwannomas, 11 cerebrospinal fluid leaks, 5 encephaloceles, 5 meningioma, 5 superior semicircular canal dehiscences, and 4 other disease processes. The approaches were middle fossa (28), translabyrinthine (20), suboccipital (3), retrosigmoid (3), and combined/other (8). Mean total anesthesia time was 6.5 hours (range 2.3 to 14 hours). Mean time between surgery and CT scan was 11 hours (range 3.5‐17). Mild pneumocephalus was almost always found, along with mild extra‐axial blood. Three patients had significant mass effect found on CT scan, but this was present preoperatively. One patient had a mild subdural without neurological decline. No patient suffered any drastic neurological decline, although one patient reported 4th and 5th finger numbness that resolved spontaneously.Conclusions:Clinically significant abnormalities on immediate postoperative CT scans were rare, as were cases of neurological decline. Further prospective studies would determine a reasonable algorithm for routine use of postoperative imaging.
In Vivo Gene Transfer into Neonatal Mice Cochlea Using Adeno‐ Associated Viral Vectors
Authors: Meyer Anais , Danos Olivier , Akil Omar , Petit Christine , Safieddine Saaid 
Published: August 2013

Objectives:Although sensory hearing loss is the most common sensory disorder, with more than 75% of genetic origin, there are no curative treatments available. A promising approach to restore inherited hearing loss consists of introducing a functional copy of the deficient gene using gene therapy. The present study develops a non‐invasive surgical approach using adeno‐associated viruses (AAV) vector to introduce reporter genes into neonatal mice cochleae, without affecting the normal development of hearing.Methods:AAV2, AAV2/8, AAV2/1, and AAV8, carrying green fluorescent protein (GFP) reporter gene, were tested using 150 neonatal mice. Two microliters of vectors, with titer of 1013 vg/ml, were injected into the scala tympani through the round window. Two weeks after viral injection, evoked auditory brain‐stem responses (ABR) were recorded; cellular expression and distribution of GFP were analyzed by immunohistochemistry and confocal imaging.Results:AAV2/8 vector transduced cochlear inner hair cells with high efficiency (80%) and to a lesser degree supporting cells (40%). Serotype 8 transduced mostly neurons (30%). The efficiency of serotypes 2/1, 1, and 2 varied from 5% to 80% of the inner hair cells and from 35% to 80% of supporting cells. The recording of the evoked ABR responses of the injected mice at P16 showed that cochlear function is not affected.Conclusions:We have developed a surgical procedure that might be useful for AAV gene transfer into the cochlea to treat genetic deafness. As a next step, a therapeutic gene will be transferred into a mouse model for human deafness to correct hearing loss.
Intraoperative Monitoring of Hearing Improvement during Ossiculoplasty by LDV‐ABR‐ECochG Technique
Authors: Morawski Krzysztof F. , Niemczyk Kazimierz , Hryciuk Aleksandra , Sokolowski Jacek , Bartoszewicz Robert 
Published: August 2013

Objectives:Assess utility of combined electrophysiological and laser‐Doppler Vibrometry (LDV) technique for intraoperative monitoring (IM) of hearing threshold (HT) improvement during ossiculoplasty.Methods:Study Design: A prospective, feasibility study. Setting: Academic, tertiary referral center. Ten patients underwent two‐stage canal wall‐up tympanoplasty due to chronic otitis media with cholestaetoma. During the second look surgery performed 6 to 9 months later, ossiculoplasty was monitored intraoperatively by LDV to assess prosthesis movability and by electrocochleography from the round window (RW‐ECochG), and by auditory brainstem responses (ABR) to evaluate HT improvement. The ear was stimulated acoustically by tone‐bursts: 0.5kHz, 1.0kHz, 2.0kHz, and 4.0kHz. Intraoperative HT, defined as the last intensity for which RW‐ECochG and ABR wave V was present, were tested for various configurations of prosthesis placement. Simultaneously for the same stimulation, LDV measured prosthesis moveability. In all subjects, pre‐ and postoperative pure tone audiometry was performed to evaluate postoperative air‐bone gap closure (ABG‐C).Results:Postoperative ABG‐C ranged between 10 and 45 dB. HT improvement evaluated intraoperatively correlated with postoperative ABG‐C. Various prosthesis configurations and placements resulted in measurable changes mostly in the RW‐ECochG thresholds. LDV appeared sensitive mostly to prosthesis position changes manifesting by movability improvement at 0.5 and 1.0kHz.Conclusions:RW‐ECochG was found to be better than ABR for IM of HT improvement, showing the best correlations with postoperative ABG‐C. RW‐ECochG and LDV showed their usefulness to control prosthesis position changes by confirming better acoustic energy transfer through the reconstructed ossicular chain.
A Lack of Association between Human Herpes Viridiae (HHV) and Vestibular Schwannoma: Analysis of 121 Cases
Authors: Bhimrao Sanjiv K. , Maguire John , Garnis Cathie , Westerberg Brian D. 
Published: August 2013

Objectives:Vestibular schwannoma (VS) is a benign tumor thatarises from the Schwann cells of the vestibular nerve. Human herpes virus (HHV) 1 and 2 have been found within the parenchyma of virtually all the organs of the body and the dorsal root ganglia of the spinal cord in humans. HHV has been shown to replicate within Schwann cells, and infection by HHV has been shown to mimic VS on magnetic resonance imaging. Others hypothesized that the likely cause of VS is HHV infection and that prior exposure to HHV‐3 is a potential risk factor in VS development. Our objective wasto assess for the presence of HHV viral DNA using immunohistochemical techniques in surgically excised vestibular schwannoma samples.Methods:Tissue microarrays (TMAs) representing sporadic and NF2‐associated vestibular schwannomas from 121 patients, as well as both positive and negative controls, were studied. TMA sections were immunostained‐using antibodies directed against HHV‐1, HHV‐2, HHV‐3, HHV‐5, and HHV‐8.Results:There was no immunohistochemically detectable HHV (HHV‐1, HHV‐2, HHV‐3, HHV‐5, HHV‐8) in any of the 121 cases of sporadic or NF2 cases analyzed.Conclusions:These data offer no support for an association between HHV and the development of sporadic or NF2 associated VS in humans.
Light‐based Contact Hearing Device: Characterization of Available Feedback Gain Margin at Two Device Microphone Locations
Authors: Perkins Rodney C. , Levy Suzanne , Puria Sunil 
Published: August 2013

Objectives:Assistive devices compensate for hearing impairment by amplifying sounds with gain, which is limited by acoustic feedback. The light‐based Contact Hearing Device (CHD) provides amplification to 10 kHz by mechanically vibrating the umbo with a wireless Tympanic Contact Actuator (TCA). Driving the eardrum mechanically generates a pressure wave, which travels laterally down the ear canal and produces feedback. Placing the microphone closer to the canal entrance may preserve more natural acoustic cues than the BTE location, although it may reduce available FGM. Our objective was to characterize the feedback gain margin (FGM) at two microphone locations using the CHD to determine if both locations are compatible with treating a broad range of hearing‐impaired subjects.Methods:Thirteen subjects with bilateral mild‐to‐severe hearing impairment were fitted with CHDs (26 ears). The TCA was driven with light‐pulses, and the feedback pressure was measured at two microphone locations: at the fossa triangularis (FT) and above the pinna at the BTE microphone location. The FGM from 1‐10 kHz was computed (FGM below 1 kHz is not measureable).Results:The mean FGM varied from 32‐48 dB and 38‐60 dB for the FT and BTE microphone locations respectively. FGM was lowest in the 3‐5 kHz range and highest at about 7 kHz. The STD of FGM varied from 5.3‐13 dB due individual anatomies.Conclusions:A microphone at the BTE has 6‐12 dB additional FGM over a microphone at a FT location and allows a broader inclusion range to fit impaired patients with amplification to 10 kHz.
Merlin Expression in Spiral Ganglion Neurons Is Decreased in Deafened Mice
Authors: Tokita Joshua , Fernando Augusta , Harpole Bethany , Shah Hetel , Hansen Marlan R. 
Published: August 2013

Objectives:1) Evaluate the expression and phosphorylation status of merlin, the protein product of the Nf2 tumor suppressor gene, in auditory neural structures before and after deafening. 2) Determine the extent to which merlin influences neurite growth in spiral ganglion neurons (SGNs). 3) Determine whether merlin expression in SGNs or spiral ganglion Schwann cells (SGSCs) inhibits neurite growth.Methods:Immunostaining of cochlear sections before and after deafening and organotypic explants with anti‐merlin antibodies were used to assess merlin expression in SGNs and SGSCs. A (Tx)‐inducible Cre‐mediated recombination system was used to knock out merlin in neonatal SGNs. Cultures were maintained with (+) or without (‐) Tx for 24h to induce Cre expression. To evaluate loss of merlin expression in SGNs versus SGSCs, we plated (+)Tx and (‐)Tx neurons onto a bed of (+)Tx and (‐)Tx SGSCs. Neurite length and branching were determined for each condition.Results:Merlin expression in SGNs raises the possibility that merlin regulates SGN neurite growth. Merlin expression in SGNs decreased in cochlear sections taken from P30 versus P60 control rats and in P30 and P60 deafened versus P30 and P60 control rats respectively. Reduced merlin expression in cultured neurons but not SCs significantly increases both the number and length of SGN neurites in SGNs.Conclusions:The pattern of merlin expression and phosphorylation following deafening in SGNs and SGSCs taken together with results indicating that neuronal expression of merlin inhibits neurite growth raises the possibility that merlin plays a role in auditory neural maintenance, regeneration, or both.
Metallurgical Considerations in Shape‐Memory Nitinol Middle Ear Prosthetics
Authors: Knox Glenn W. 
Published: August 2013

Objectives:At the conclusion of this presentation, the participants should be able to 1) describe how the metallurgical phenomenon of creep may be involved in the failure of nitinol middle ear devices, and 2) describe how other metallurgical phenomena such as microfractures can also be involved.Methods:Retrospective literature review of nitinol middle ear device failure; retrospective literature review of known metallurgical properties of nitinol such as creep and microfractures; and prospective survey of otologic surgeons. Study period: January 2001 to present (literature review), and 2011 to present (survey). Condition studied: Delayed conductive hearing loss after stapes surgery. Subjects studied: Patients with otosclerosis described in previous studies who underwent surgery with nitinol shape‐memory devices. Surgeons who implanted such devices. Interventions: Analysis of known metallurgical properties of nitinol applied to results obtained with such devices.Results:A comprehensive literature review revealed many instances of delayed conductive hearing loss after middle ear surgery with nitinol shape‐memory devices. A survey of otologic surgeons by the author revealed 50% of surgeons reporting “loose‐wire” syndrome as a delayed complication of such surgeries, signifcant to P < 0.05 confidence level (94 surgeons).Conclusions:1) “Loose‐wire” syndrome is a frequent complication encountered by surgeons performing middle‐ear surgery with nitinol shape‐memory devices. 2) Metallurgical properties of nitinol such as creep (deformation over time as a result of stress) and microfractures may theoretically be responsible. 3) Additional metallurgical laboratory analysis of nitinol is indicated in order to explain and prevent such complications.