Selective Retrosigmoid Vestibular Neurectomy Without Internal Auditory Canal Drill-out: an Anatomic Study

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Mar, 2002  |  Pubmed ID: 11875353

It is well established that selective vestibular nerve section by means of the retrosigmoid or posterior fossa approach can be accomplished with or without drill-out of the internal auditory canal (IAC) by virtue of the presence or absence of a surgically accessible cleavage plane between the vestibular and cochlear nerves. Some reports have indicated that a majority of patients would be amenable to successful separation of the vestibular nerve from the cochlear nerve medial to the IAC, thus obviating the need for IAC drill-out and associated complications. However, other reports have indicated routine difficulty in finding a satisfactory vestibulocochlear cleavage plane within the cerebellopontine angle. This in situ cadaver study was undertaken to determine whether normal anatomic relationships support the hypothesis that selective vestibular nerve section can be accomplished by means of the posterior fossa approach without the need for concomitant IAC drill-out in a majority of circumstances.

Hearing Preservation Surgery for Small Endolymphatic Sac Tumors in Patients with Von Hippel-Lindau Syndrome

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. May, 2002  |  Pubmed ID: 11981399

To determine the incidence of bilateral endolymphatic sac tumors in von Hippel-Lindau syndrome and to describe the technique and results of hearing preservation surgery for small endolymphatic sac tumors in a series of patients with von Hippel-Lindau syndrome.

Revision Tympanomastoid Surgery

Ear, Nose, & Throat Journal. Oct, 2002  |  Pubmed ID: 12405093

We conducted a retrospective study of 50 ears in 48 patients in whom we performed revision tympanomastoid surgery for chronic otitis media. We found that the most common probable causes for the failure of previous surgery were incomplete lowering of the facial ridge (94% of cases), persistent sinodural-angle air-cell disease (92%), persistent tegmental air-cell disease (88%), recurrent or persistent cholesteatoma (66%), persistent mastoid-tip air-cell disease (62%), a small meatus (60%), and persistent hypotympanic air-cell disease (56%). After a mean postoperative follow-up of 26 months, we found no appreciable difference in success rates between patients who had undergone only one previous surgery (93%) and those who had undergone more than one previous surgery (95%) prior to referral to our center. Follow-up hearing data revealed a statistically significant improvement in air and bone conduction and a nonsignificant reduction in the air-bone gap. We conclude that revision mastoid surgery following multiple earlier surgical failures does not carry an appreciably higher risk of failure than does initial revision surgery. Moreover, there appears to have been no change in the causes of failure following mastoid surgery over the past 3 decades.

Correlation Between Hearing Loss and Scala Media Area in Guinea Pigs with Long-standing Endolymphatic Hydrops

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Jan, 2003  |  Pubmed ID: 12544031

Histologic analysis of the hydropic and normal guinea pig cochleae was undertaken to assess a potential correlation between the magnitude of endolymphatic hydrops and hearing loss. It was hypothesized that a greater correlation than previously reported might be found by looking at long-standing endolymphatic hydrops and high-frequency range hearing.

Serum Antidiuretic Hormone Levels in Patients with Unilateral Meniere's Disease

The Laryngoscope. Aug, 2003  |  Pubmed ID: 12897553

Prior studies have indicated a possible role of antidiuretic hormone (ADH) in the pathogenesis of Meniere's disease. Animal studies have shown presence of ADH receptors in the inner ear, and chronic vasopressin administration has been shown to induce endolymphatic hydrops. Furthermore, elevation of serum ADH levels in human has been noted in patients with Meniere's disease. The goal of the study report was to analyze ADH levels in a series of patients with definite unilateral Meniere's disease to further investigate this relationship.

Cochlear Implantation in a Patient with Neurofibromatosis Type 1 and Profound Hearing Loss: Evidence to Support a Cochlear Site of Lesion

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Sep, 2003  |  Pubmed ID: 14501452

To determine the efficacy of cochlear implantation in an individual with neurofibromatosis type 1 and profound hearing loss and to determine, to the extent possible in a living subject, the site of lesion of the hearing loss in an individual with neurofibromatosis type 1.

Metastatic Hepatocellular Carcinoma to the Temporal Bone in a Post-liver Transplant Patient

Otolaryngology--head and Neck Surgery : Official Journal of American Academy of Otolaryngology-Head and Neck Surgery. Mar, 2004  |  Pubmed ID: 15054383

Fabrication of Tissue Engineered Tympanic Membrane Patches Using Computer-aided Design and Injection Molding

The Laryngoscope. Jul, 2004  |  Pubmed ID: 15235363

The goal of the current study was to use computer-aided design and injection molding technologies to tissue engineer precisely shaped cartilage in the shape of butterfly tympanic membrane patches out of chondrocyte-seeded calcium alginate gels.

Differential Grading of Endolymphatic Sac Tumor Extension by Virtue of Von Hippel-Lindau Disease Status

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Sep, 2004  |  Pubmed ID: 15354010

Endolymphatic sac tumors are aggressive papillary tumors of the temporal bone frequently associated with von Hippel-Lindau disease. The goal of this study was to use a newly devised classification system as a means to analyze differences between endolymphatic sac tumor extension in von Hippel-Lindau disease and non-von Hippel-Lindau disease patients.

Endolymphatic Duct Violation During Retrosigmoid Dissection of the Internal Auditory Canal: a Human Temporal Bone Radiographic Study

The Laryngoscope. Nov, 2004  |  Pubmed ID: 15510017

Successful hearing preservation after acoustic neuroma resection is sometimes complicated by delayed hearing deterioration. The goal of this study was to investigate the hypothesis that internal auditory canal (IAC) drilling during retrosigmoid acoustic neuroma removal may result in endolymphatic duct (ELD) injury, a potential cause of delayed hearing loss (HL) after hearing preservation surgery.

Obstructing Lesions of the Endolymphatic Sac and Duct Mimicking Ménière's Disease

Ear, Nose, & Throat Journal. Nov, 2004  |  Pubmed ID: 15628631

In this retrospective case series and literature review, we demonstrate that temporal bone lesions that obstruct the endolymphatic sac or duct can cause symptoms of Ménière's disease. This finding is likely attributable to endolymphatic hydrops; initially, such cases typically masquerade as Ménière's disease. Between July 1995 and April 2002, a total of 379 patients were treated for an initial diagnosis of Ménière's disease at our institution. Among this group, 3 patients were found to have an obstructing lesion of the endolymphatic sac or duct that we felt was causally related to their Ménière's-like symptomatology. We reviewed these cases and noted the similarities in each patient's presentation, including a common pathophysiology. On imaging studies, each patient had a different pathologic lesion that involved the endolymphatic sac or duct: patient 1 had a jugular megabulb, and she was ultimately treated with vestibular nerve section; patient 2 had a cholesterol granuloma, which was treated with surgical excision; patient 3 had an endolymphatic sac tumor that was treated with surgical excision. As has been suggested in previous reports, not all cases of Ménière's disease are idiopathic. We conclude that obstruction of the endolymphatic sac or vestibular aqueduct by a mass lesion or vascular anomaly can lead to vestibulocochlear pathology that mimics Ménière's disease.

Cochlear Implant Complications: Utility of Federal Database in Systematic Analysis

Archives of Otolaryngology--head & Neck Surgery. Mar, 2005  |  Pubmed ID: 15781766

To explore the suitability of the Manufacturer User Facility and Distributor Experience (MAUDE) database (which is maintained by the Food and Drug Administration and has a mandatory reporting requirement) for systemic analysis of cochlear implant complications and treatments and, in so doing, analyze trends in cochlear implant complications for 2 periods, 2002 and pre-1998.

I Cannot Smile or Wink Anymore: Facial Nerve Weakness After Acoustic Neuroma Surgery

Current Surgery. Mar-Apr, 2005  |  Pubmed ID: 15796934

Vestibular-evoked Myogenic Potentials in Infancy and Early Childhood

The Laryngoscope. Aug, 2005  |  Pubmed ID: 16094120

Hearing impairment and the often concurrent loss of vestibular function, which is rarely assessed in infants, can both impair sensory integration critical to the development of normal motor coordination. This study demonstrates, for the first time, that vestibular function in infants can be noninvasively assessed using vestibular-evoked myogenic potentials (VEMPs). Our intentions were to demonstrate that VEMPs can be reliably recorded from neonates and to compare neonatal VEMPs with those obtained from normal adults.

Endolymphatic Sac Tumor Metastatic to the Spine. Case Report

Journal of Neurosurgery. Spine. Jul, 2005  |  Pubmed ID: 16122027

Endolymphatic sac tumors (ELSTs) are aggressive papillary lesions of the temporal bone. Although histologically benign, they may exhibit invasive growth and destruction of the skull base. Patients generally present with symptoms referable to the lesion's location within the middle or posterior cranial fossa. Although well characterized as a distinct entity, ELSTs involved in metastatic dissemination have never been reported. In the present report the authors describe a case of ELST metastatic to the spine treated with resection.

Diameter of the Cochlear Nerve in Endolymphatic Hydrops: Implications for the Etiology of Hearing Loss in Ménière's Disease

The Laryngoscope. Sep, 2005  |  Pubmed ID: 16148690

Endolymphatic hydrops (ELH) is an important histopathological hallmark of Ménière's disease. Experimental data from human temporal bones as well as animal models of the disorder have generally failed to determine the mechanism by which ELH or related pathology causes hearing loss. Hair cell and spiral ganglion cell counts in both human and animal case studies have not, for the most part, shown severe enough deterioration to explain associated severe sensorineural hearing loss. However a limited number of detailed ultrastructural studies have demonstrated significant reductions in dendritic innervation densities, raising the possibility that neurotoxicity plays an important role in the pathology of Ménière's disease (MD) as well as experimental endolymphatic hydrops (ELH). This study tests the hypothesis that neurotoxicity is an important primary mediator of injury to the hydropic ear and is reflected in measurable deterioration of the cochlear nerve in the animal model of ELH. This study also explores the previously presented hypothesis that cochlear injury in ELH is mediated through the actions of nitric oxide (NO) by evaluating whether hearing loss or various measures of cochlear damage can be ameliorated by administration of an agent that limits excess production of NO.

The Basic Science of Meniere's Disease and Endolymphatic Hydrops

Current Opinion in Otolaryngology & Head and Neck Surgery. Oct, 2005  |  Pubmed ID: 16160525

Meniere's disease is characterized by the triad of fluctuating hearing loss, episodic vertigo, and tinnitus and by endolymphatic hydrops found on post-mortem examination. The cause of Meniere's disease remains unclear. Numerous factors play a role in the development of hydrops and in the pathogenesis of related cochleovestibular dysfunction. This review highlights recent advances in the understanding of the pathophysiology of symptom development in Meniere's disease by detailing the role of genetics, autoimmunity, endolymphatic fluid homeostasis, excitotoxicity, oxidative stress, and cellular apoptosis. Emphasis is placed on reviewing the newly described animal models that exhibit endolymphatic hydrops.

Treatment of Glomus Jugulare Tumors in Patients with Advanced Age: Planned Limited Surgical Resection Followed by Staged Gamma Knife Radiosurgery: a Preliminary Report

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Nov, 2005  |  Pubmed ID: 16272947

To minimize treatment comorbidities in glomus jugulare tumor patients with advanced age while reducing pulsatile tinnitus and preserving or improving residual hearing using a limited middle ear/mastoid tumor resection and postoperative gamma knife radiosurgery to tumor remnants in the jugular foramen region.

Endolymphatic Duct Status During Middle Fossa Dissection of the Internal Auditory Canal: a Human Temporal Bone Radiographic Study

The Laryngoscope. Mar, 2006  |  Pubmed ID: 16540891

Successful hearing preservation after acoustic neuroma resection is sometimes complicated by delayed hearing deterioration. The middle fossa approach appears to offer superior long-term hearing results when compared to the retrosigmoid surgical approach. The goal of this study is to investigate the hypothesis that internal auditory canal (IAC) drilling during middle fossa acoustic neuroma removal is associated with a lower incidence of endolymphatic duct (ELD) injury, a potential cause of delayed hearing loss (HL) known to accompany retrosigmoid hearing preservation dissection techniques.

Tissue-engineered Calcium Alginate Patches in the Repair of Chronic Chinchilla Tympanic Membrane Perforations

The Laryngoscope. May, 2006  |  Pubmed ID: 16652074

Chronic tympanic membrane perforations are a common problem in the United States. A high number of these cases results from placement of pressure equalization tubes. These perforations may initially be treated with paper patch techniques and although safe and well tolerated, the procedure demonstrates poor efficacy. The ideal treatment for small perforations should be rapid, minimally invasive, and efficacious. Calcium alginate-based tissue engineered tympanic membrane patches represent an attractive option, but in vivo data are required.

Effect of Incus Removal on Middle Ear Acoustic Sensor for a Fully Implantable Cochlear Prosthesis

Conference Proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference. 2006  |  Pubmed ID: 17945982

System miniaturization and steady progress towards a totally implantable prosthetic system is the current trend in cochlear implant technology. To achieve this objective, the external microphone of present implants needs to be implantable. This goal can be accomplished by placing a miniature accelerometer on the ossicular chain in the middle ear to detect and convert bone vibrations into an electrical signal for further processing and stimulating cochlear electrodes. This paper describes the characterization of the umbo of a human temporal bone before and after the removal of the incus to determine the impact of the resulting change in umbo mechanics and attached accelerometer performance. With the removal of the incus, the umbo vibration acceleration frequency response in the direction perpendicular to the tympanic membrane increases by 5 dB below 2 kHz. Above 2 kHz the response diverges due to the change of ossicular chain resonant frequency caused by the removal of the incus. However, at each frequency the umbo vibration acceleration exhibits a linear function of the input sound pressure level (SPL) with a slope of 20 dB per decade before and after removal of the incus. A commercial accelerometer attached to the umbo shows similar characteristics. From the measurement results of umbo characterization, a miniaturized implantable accelerometer with a packaged mass below 20 milligrams, a sensing resolution of 35 microg rms/square root Hz, and a bandwidth of 10 kHz would be required to detect normal conversation.

The Pathophysiology of Cholesteatoma

Otolaryngologic Clinics of North America. Dec, 2006  |  Pubmed ID: 17097438

The pathogenesis of middle ear cholesteatoma continues to be highly debated. In recent years, there has been a substantial improvement in the understanding of the pathophysiology of this disease. This chapter provides a summary of the history and evolution of cholesteatoma and a review of the recent literature that pertains to the pathophysiology of congenital and acquired cholesteatoma. An emphasis is placed on the mechanism of osteolysis and the factors predictive of aggressiveness and recidivism.

Molecular Changes Associated with the Endolymphatic Hydrops Model

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Sep, 2007  |  Pubmed ID: 17468674

Hearing loss and cochlear degeneration in the guinea pig model of endolymphatic hydrops (ELH) results, in part, from toxic levels of excitatory amino acids (EAAs) such as glutamate, which in turn leads to changes in the expression of genes linked to intracellular glutamate homeostasis and apoptosis, leading to neuronal cell death.

Evaluation and Management of Endolymphatic Sac and Duct Tumors

Otolaryngologic Clinics of North America. Jun, 2007  |  Pubmed ID: 17544692

The endolymphatic sac tumor is a slow-growing, locally aggressive neoplasm that originates from the epithelium of the endolymphatic sac and duct. Disease progression can lead to profound sensorineural hearing loss, posterior fossa invasion, brainstem compression, drop metastasis, and eventual death. Early diagnosis and surgical attention are the primary objectives in the management of patients who have endolymphatic sac tumor. This article describes the latest rationale and techniques for hearing preservation surgery and a review of the latest developments surrounding this disease entity.

Re: Cochlear Implantation for Hearing Loss Associated with Bilateral Endolymphatic Sac Tumors in Von Hippel-Lindau Disease

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Dec, 2007  |  Pubmed ID: 17728688

Inflammatory Pseudotumor of the Middle Ear Masquerading As Bell's Palsy

American Journal of Otolaryngology. Nov-Dec, 2007  |  Pubmed ID: 17980777

We describe the case of a 28-year-old woman who presented with an acute dense left facial paralysis. Magnetic resonance imaging demonstrated enhancement of the labyrinthine portion of the facial nerve, and Bell's palsy was the presumed initial diagnosis. After 2 months without recovery despite receiving steroid and antiviral therapy, the patient underwent further workup. Computed tomographic scan demonstrated a mass lesion adjacent to the tympanic portion of the facial nerve, and electromyography showed active denervation and prominent fibrillation potentials. Surgical excision of the tumor was performed with decompression and sparing of the facial nerve. Histologically, the tumor proved to be an inflammatory pseudotumor (IPT). At the 3-year follow-up, the patient had an improvement in her facial nerve function, progressing to a House-Brackman grade III. An IPT can masquerade as Bell's palsy with sudden complete facial paralysis. Failure to obtain even slight recovery in Bell's palsy should prompt further workup, including appropriate imaging, to assess for a mass lesion. Confusion of an IPT with a nerve-based tumor on frozen section and imaging could lead to inappropriate resection and cable grafting of the facial nerve. Therefore, the relationship between an IPT and facial nerve paralysis is vital and must be recognized for treatment and to maximize postoperative facial nerve function.

A Laboratory Study on a Capacitive Displacement Sensor As an Implant Microphone in Totally Implant Cochlear Hearing Aid Systems

Conference Proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference. 2007  |  Pubmed ID: 18003304

A totally implant cochlear hearing aids system, integrating an implant microphone, interface electronics, a speech processor, a stimulator, and cochlear electrodes, can overcome the uncomfortable, inconvenient, and stigma problems associated with the conventional and semi-implantable hearing aids. This paper presents a laboratory feasibility study on the use of an electret condenser microphone (ECM) displacement sensor, serving as an implant microphone, and combined with a spring coupler to directly sense the umbo acoustic vibration. The umbo vibration characteristics were extracted from literature to determine the coupler and sensor requirements. A laboratory model was built to simulate the vibration source and experimentally study the transmission coefficient. Experimental data demonstrate that by using a 5 N/m stiffness spring, the umbo vibration amplitude as high as 67% can be transmitted to the sensor. Measurement of the sensor system on the temporal bone was also made. The minimum detectable sound pressure level (SPL) at 1 kHz is 41 and 67 dB for laboratory and 38 and 64 dB for temporal bone measurement for 1 and 388 Hz bandwidth, respectively. Better performance was achieved in a higher frequency. Results and analysis of this study can be used as a guideline for the future design of displacement sensors as implant microphones.

Optimization of Ribonucleic Acid Detection from Archival Guinea Pig Temporal Bone Specimens

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Jan, 2007  |  Pubmed ID: 16983313

The choice of ribonucleic acid (RNA) isolation protocol coupled with modifications to RNA extraction and detection procedures may result in a more reliable method to detect gene expression in archived temporal bones.

A Mouse Model with Postnatal Endolymphatic Hydrops and Hearing Loss

Hearing Research. Mar, 2008  |  Pubmed ID: 18289812

Endolymphatic hydrops (ELH), hearing loss and neuronal degeneration occur together in a variety of clinically significant disorders, including Meniere's disease (MD). However, the sequence of these pathological changes and their relationship to each other are not well understood. In this regard, an animal model that spontaneously develops these features postnatally would be useful for research purposes. A search for such a model led us to the Phex Hyp-Duk mouse, a mutant allele of the Phex gene causing X-linked hypophosphatemic rickets. The hemizygous male (Phex Hyp-Duk/Y) was previously reported to exhibit various abnormalities during adulthood, including thickening of bone, ELH and hearing loss. The reported inner-ear phenotype was suggestive of progressive pathology and spontaneous development of ELH postnatally, but not conclusive. The main focuses of this report are to further characterize the inner ear phenotype in Phex Hyp-Duk/Y mice and to test the hypotheses that (a) the Phex Hyp-Duk/Y mouse develops ELH and hearing loss postnatally, and (b) the development of ELH in the Phex Hyp-Duk/Y mouse is associated with obstruction of the endolymphatic duct (ED) due to thickening of the surrounding bone. Auditory brainstem response (ABR) recordings at various times points and histological analysis of representative temporal bones reveal that Phex Hyp-Duk/Y mice typically develop adult onset, asymmetric, progressive hearing loss closely followed by the onset of ELH. ABR and histological data show that functional degeneration precedes structural degeneration. The major degenerative correlate of hearing loss and ELH in the mutants is the primary loss of spiral ganglion cells. Further, Phex Hyp-Duk/Y mice develop ELH without evidence of ED obstruction, supporting the idea that ELH can be induced by a mechanism other than the blockade of longitudinal flow of endolymphatic fluid, and occlusion of ED is not a prerequisite for the development of ELH in patients.

Spiral Ganglion Degeneration Patterns in Endolymphatic Hydrops

The Laryngoscope. Jul, 2008  |  Pubmed ID: 18364591

The mechanistic association between endolymphatic hydrops (ELH) and hearing loss (HL) is unclear. Although ELH severity has been shown to correlate in some studies with HL, injury of vital structures, including hair cells and the cochlear nerve, have failed to demonstrate correlation with ELH severity. The goal of this study is to evaluate the hypothesis that spiral ganglion cell degeneration is the principle pathologic site of ELH-related cochlear injury, correlates with ELH severity, and is most profound in the apical region.

Temporal Bone Fracture: Evaluation and Management in the Modern Era

Otolaryngologic Clinics of North America. Jun, 2008  |  Pubmed ID: 18436001

Temporal bone fractures occur from high-energy mechanisms, typically but not limited to motor vehicle accidents. However, as the automotive industry continues to introduce improved safety measures, violence and falls account for a larger proportion of cases. Given the great forces involved, temporal bone fractures rarely occur in isolation and initial evaluation must focus on the fundamental ABCs of Advanced Trauma Life Support with special attention to Glasgow Coma Scale, intracranial injury, and cervical spine injury. Subsequent evaluation relies on physical examination, high-resolution CT, and electrodiagnostic testing to address the neurotologic consequences of temporal bone fracture, including cerebrospinal fluid leak, facial nerve injury, and injury to the peripheral hearing and balance organs. Management algorithms must address immediate (eg, ABCs, neurosurgical issues), short-term (eg, cerebrospinal fluid leak, facial nerve injury, hearing loss), long-term (eg, facial nerve injury, hearing loss, vestibular injury), and delayed (eg, encephalocele, cholesteatoma, late meningitis) issues. This article reviews the current state of temporal bone fracture evaluation and management with special attention to mechanisms of injury, clinical presentations and emergency evaluation, and diagnostic workup, including the evolution of radiographic fracture classification systems and electrodiagnostic testing. Discussion of treatment approaches address management of immediate, short-term, long-term, and delayed complications.

Current Assessment and Management of Glomus Tumors

Current Opinion in Otolaryngology & Head and Neck Surgery. Oct, 2008  |  Pubmed ID: 18797283

To provide an overview on the recent advances in the diagnosis and treatment of glomus tumors (paragangliomas).

Staged Gamma Knife Radiosurgery After Tailored Surgical Resection: a Novel Treatment Paradigm for Glomus Jugulare Tumors

Stereotactic and Functional Neurosurgery. 2009  |  Pubmed ID: 19174618

Although benign and slow growing, glomus jugulare tumors can be locally aggressive because of their proximity to lower cranial nerves and major vascular structures. Surgical resection frequently leads to complications, and radiosurgery alone often does not relieve symptoms. We report a novel treatment paradigm of tailored surgical resection followed by staged radiosurgery that allows for tissue diagnosis and immediate improvement of symptoms and tumor control without the morbidity of radical surgical resection.

Vestibular Evoked Myogenic Potentials in Normal Mice and Phex Mice with Spontaneous Endolymphatic Hydrops

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Jun, 2009  |  Pubmed ID: 19300299

Vestibular evoked myogenic potentials (VEMPs) have been recorded from the neck musculature and the cervical spinal cord in humans and a limited number of laboratory animals in response to loud sound. However, the mouse VEMP has yet to be described. Evaluation of the sacculocollic pathway via VEMPs in mice can set the stage for future evaluations of mutant mice that now play an important role in research regarding human auditory and vestibular dysfunction.

Management of Anterior Inferior Cerebellar Artery Aneurysms: an Illustrative Case and Review of Literature

Neurosurgical Focus. May, 2009  |  Pubmed ID: 19409007

Aneurysms of the anterior inferior cerebellar artery (AICA) are relatively rare among intracranial aneurysms. They can occur in 1 of 3 regions of the AICA: 1) craniocaudal (high or low riding), 2) mediolateral-premeatal (proximal), and 3) meatal-postmeatal (distal). The management strategies for treatment differ according to the location and configuration of the aneurysm. The existing body of neurosurgical literature contains articles published on aneurysms arising from the AICA near the basilar artery (BA), intracanalicular/meatal aneurysms, and distal AICA. Several therapeutic options exist, encompassing microsurgical and endovascular techniques. The authors describe a case of treatment involving a large BA-AICA aneurysm approached via exposure of the presigmoid dura using a retromastoid suboccipital craniectomy and partial petrosectomy. Treatment of these lesions requires detailed knowledge of the anatomy, and an anatomical overview of the AICA with its arterial loops and significant branches is presented, including a discussion of the internal auditory (labyrinthine) artery, recurrent perforating arteries, subarcuate artery, and cerebellosubarcuate artery. The authors discuss the various surgical approaches (retromastoid, far lateral, subtemporal, and transclival) with appropriate illustrations, citing the advantages and disadvantages in accessing these AICA lesions in relation to these approaches. The complications of these different surgical techniques and possible clinical effects of parent artery occlusion during AICA surgery are highlighted.

Outpatient Repair of Superior Semicircular Canal Dehiscence Via the Transmastoid Approach

The Laryngoscope. Sep, 2009  |  Pubmed ID: 19554641

Superior semicircular canal dehiscence (SSCD) syndrome has been a topic of much interest since its first description a decade ago. The symptoms of vertigo, autophony, and Tullio phenomenon have been well described as has the utility of surgical repair. The standard approach described for surgical repair of this problem has been to perform a middle fossa craniotomy followed by plugging of the superior semicircular canal. Recently, a transmastoid approach has been described as another surgical option in cases of SSCD, an alternative that could avoid the known risks of a middle fossa craniotomy. Herein we present further data for validation of the transmastoid SSCD repair technique. Additional factors leading to the successful treatment of these patients in the outpatient setting, an approach not previously described, are detailed.

Radiosurgery for Glomus Jugulare Tumors

Otolaryngologic Clinics of North America. Aug, 2009  |  Pubmed ID: 19751873

Glomus jugulare tumors arise from adventitial chemoreceptor tissue in the jugular bulb. Although histologically benign, these tumors can be locally aggressive because of their proximity to the lower cranial nerves and major vascular structures. Traditional treatment involves microsurgical removal with or without endovascular embolization, but morbidity following total resection can result in injury to the facial and lower cranial nerves. Radiosurgery has recently emerged as a promising alternative to older therapeutic strategies for treatment of glomus jugulare tumors. This article reviews the latest benefits of radiosurgery and demonstrates how this modality represents an effective treatment option for glomus jugulare tumors with excellent tumor control and low risk for morbidity. In addition, this article will detail the role of minimally invasive sub-total resection of glomus jugulare tumors as a surgical complement to gamma knife therapy.

Spiral Ganglion Loss Outpaces Inner Hair Cell Loss in Endolymphatic Hydrops

The Laryngoscope. Jan, 2010  |  Pubmed ID: 19877178

Neuronal toxicity is thought to be important in Meniere's disease and experimental endolymphatic hydrops (ELH). This study quantifies the relationship between neuronal degeneration and hair cell degeneration in ELH to evaluate the hypothesis that a primary neural insult would yield greater loss in the spiral ganglion than at the inner hair cell level.

Characterization of Ossicular Chain Vibration at the Umbo: Implications for a Middle Ear Microelectromechanical System Design

Ear, Nose, & Throat Journal. Jan, 2010  |  Pubmed ID: 20155695

We propose the use of a microelectromechanical system (MEMS) accelerometer as a middle ear microphone for future totally implantable cochlear prostheses. The MEMS accelerometer would be attached to the umbo to detect and convert the natural bone vibration that occurs in response to external sounds into an electrical signal that represents the acoustic information. The signal could be further processed to stimulate cochlear implant electrodes. To determine the feasibility of our proposal, we conducted a study to investigate whether the characteristics of umbo vibration along two orthogonal axes-one axis being perpendicular to the tympanic membrane and the other axis being parallel to the tympanic membrane plane but orthogonal to the long process of the malleus-differ significantly enough to compromise the sensing performance of the proposed accelerometer should a position misalignment occur during the implant procedure. We used laser Doppler vibrometry to measure the displacement of the umbo along the two orthogonal axes in 4 cadaveric temporal bones at multiple frequencies within the audible spectrum. We found that the peak-to-peak displacement frequency response along both axes was nearly flat from 250 Hz to 1 kHz, and it gradually rolled off with a slope of approximately -20 dB and -40 dB per decade above 1 kHz and 4 kHz, respectively. At each frequency, the displacement exhibited a linear function of the input sound level with a slope of 20 dB per decade. A comparison of measurements along the two axes indicated a similar frequency response, with an average amplitude difference of 20%. The characterization data suggest that the performance of a miniature ossicular vibration-sensing device attached on the umbo would not be degraded in the event of a position misalignment. The data also indicate that a MEMS accelerometer needs to achieve a resolution of 35 i g/sqrt[Hz] to detect normal conversation.

Contemporary Perspectives on the Pathophysiology of Meniere's Disease: Implications for Treatment

Current Opinion in Otolaryngology & Head and Neck Surgery. Oct, 2010  |  Pubmed ID: 20639763

Meniere's disease is characterized by episodic vertigo, fluctuating hearing loss, aural fullness and tinnitus. Endolymphatic hydrops, found on post-mortem examination, is the histologic hallmark. Recent research suggests that endolymphatic hydrops results from cytochemical perturbations of unknown etiology that lead to disturbance of the normal endolymphatic fluid homeostasis. This consequent hydropic state or the associated cytochemical perturbations appears to create a neurotoxic environment that ultimately leads to spiral ganglion cell death likely via the apoptotic mechanism. This review highlights some of the recent advances in the understanding of the pathophysiology of endolymphatic hydrops and progressive cochleovestibular deterioration, with emphasis placed on its potential therapeutic implications.

Pharmacological Protection of Hearing Loss in the Mouse Model of Endolymphatic Hydrops

The Laryngoscope. Aug, 2010  |  Pubmed ID: 20641076

Excitotoxic and related inflammatory injury are implicated in the spiral ganglion degeneration seen with Meniere's disease and endolymphatic hydrops (ELH). Excitotoxicity is initiated with glutamate elevation and associated with downstream increases in reactive oxygen species resulting in inflammation-mediated neuronal degeneration. This study tests the hypothesis that interruption of the initial and/or downstream aspects of excitotoxicity should provide hearing protection in ELH-associated hearing loss.

Lack of Financial Barriers to Pediatric Cochlear Implantation: Impact of Socioeconomic Status on Access and Outcomes

Archives of Otolaryngology--head & Neck Surgery. Jul, 2010  |  Pubmed ID: 20644058

(1) To analyze if socioeconomic status influences access to cochlear implantation in an environment with adequate Medicaid reimbursement. (2) To determine the impact of socioeconomic status on outcomes after unilateral cochlear implantation.

Cochlear Implantation Outcomes in Patients with Autoimmune and Immune-mediated Inner Ear Disease

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Oct, 2010  |  Pubmed ID: 20729775

To compare hearing outcomes in patients with autoimmune inner ear disease (AIED) undergoing cochlear implantation to a group of controls, postlingually deafened by non-immune-mediated causes.

A Novel Method of Translabyrinthine Cranioplasty Using Hydroxyapatite Cement and Titanium Mesh: a Technical Report

Skull Base : Official Journal of North American Skull Base Society ... [et Al.]. May, 2010  |  Pubmed ID: 21318032

We report a novel technique for closure using titanium mesh cranioplasty in addition to hydroxyapatite cement and abdominal fat graft for acoustic neuroma. We reviewed 15 patients who underwent translabyrinthine craniectomy for resection of acoustic neuroma. Hearing loss was documented prior to surgical procedure. Over 2 years, patients underwent titanium mesh and hydroxyapatite cranioplasty with abdominal fat graft. Participants included seven men and eight women, age range 38 to 65. Main outcome measures included cosmetic outcome and incidence of cerebrospinal fluid (CSF) leak. The lesion was right-sided in seven patients and left-sided in eight. Cosmetic outcome was excellent in all. There were no cases of CSF leak. Closure used one-third the hydroxyapatite required for traditional closure. Our technique yields cosmetic results equivalent to hydroxyapatite cement alone and a comparable incidence of CSF leakage without leaving a drain in place postoperatively. The technique is easy to adopt, is more cost-effective than hydroxyapatite cement cranioplasty alone, offers greater ease of access for reoperation, and does not preclude later implantation of bone-anchored hearing aid.

Cavernous Malformation of the Trochlear Nerve: Case Report and Review of the Literature on Cranial Nerve Cavernomas

Neurosurgery. Jul, 2011  |  Pubmed ID: 21471828

Cavernous malformations (CMs) arising intrinsically to the cisternal segment of the trochlear nerve are extremely rare. This case of a trochlear nerve cavernous angioma is the third to be reported in the neurosurgical literature and the first to be resected by a middle fossa approach.

Ménière's Disease: a Challenging and Relentless Disorder

Otolaryngologic Clinics of North America. Apr, 2011  |  Pubmed ID: 21474013

Ménière's disease (MD) is characterized by episodic vertigo, fluctuating hearing loss and tinnitus, and by the presence of endolymphatic hydrops on postmortem examination. This disease continues to be a diagnostic and therapeutic challenge. Patients with MD range from minimally symptomatic, highly functional individuals to severely affected, disabled patients. Current management strategies are designed to control the acute and recurrent vestibulopathy but offer minimal remedy for the progressive cochlear dysfunction. Recent research highlights the role of neurotoxicity in the pathogenesis of the cochleovestibular deterioration. This article discusses a patient with MD, and provides an algorithm for the management of this disease.

Transmastoid Extradural-intracranial Approach for Repair of Transtemporal Meningoencephalocele: a Review of 31 Consecutive Cases

The Laryngoscope. Aug, 2011  |  Pubmed ID: 21647915

To review the clinical presentation, surgical techniques, and outcomes of the transmastoid extradural-intracranial (TMEDIC) approach for the treatment of transtemporal meningoencephalocele.

Hearing Preservation in Guinea Pigs with Long-standing Endolymphatic Hydrops

Otology & Neurotology : Official Publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology. Dec, 2011  |  Pubmed ID: 22015942

Interruption of the excitotoxic and inflammatory pathways implicated in endolymphatic hydrops (ELH)-associated hearing loss (HL) should afford hearing protection at the neuronal level.

Subcutaneous Emphysema After Otologic Surgery: a Case Report

American Journal of Otolaryngology. Dec, 2011  |  Pubmed ID: 22178205

Subcutaneous emphysema of the head and neck after otologic surgery is exceedingly rare. The mechanism relates to the intimate relationship of the temporomandibular joint to the external auditory canal. We present a rare case of subcutaneous emphysema after otologic surgery for ear disease. An astute clinical index of suspicion coupled with prompt treatment can help minimize morbidity and improve patient outcomes.