18F-fluorodeoxyglucose positron emission tomography/computed tomography in predicting overall survival of oral cavity squamous cell carcinoma: Ongoing controversy.

We aimed to retrospectively determine if initial staging 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/ CT) can predict overall survival (OS) in oral cavity squamous cell carcinoma (OCSCC), which is currently a source of ongoing controversy in the literature. Forty-six consecutive patients with nonmetastatic (Stage M0) OCSCC had 18F-FDG PET/CT prior to definitive surgical treatment followed by observation or adjuvant treatment at our institution between 2006 and 2012. The median follow-up time was 18 months (range 0.1-76 months). Univariate and multivariate analysis were used to determine the ability of imaging, pathologic, and demographic factors to predict OS. 18F-FDG PET/CT parameters were standardized uptake value (SUV) maximum and mean, metabolic tumor volume, and total lesional glycolysis (TLG) of primary tumor and regional nodes. Significant predictors of OS in the multivariate analysis were primary tumor SUV mean, nodal TLG, and age. Two-year OS of patients with primary tumor SUV mean below and above the median of 6.26 was 68% and estimated 28%, respectively. Two-year OS of patients with nodal TLG below and above median of 7.9 was 69% and 34%, respectively. Two-year OS of patients younger and older than median age of 57 was 60% and 43%, respectively. Our results suggest that 18F-FDG PET/CT may be a valuable addition to multifactorial models predicting outcome for OCSCC. Thus, continued research aiming to incorporate 18F-FDG PET/CT parameters in risk-stratification algorithms for OCSCC is warranted and should be conducted using more standardized prognostic models driven by a specific clinical question.

Head and Neck Cancer Soft Tissue Radiation Necrosis-Diagnostic Challenge.

A 53-year-old man with T4aN2cM0 tongue base squamous cell carcinoma received definitive chemoradiation. FDG PET/CT at 6 weeks showed partial metabolic response with soft tissue air indicating radiation necrosis at primary site and complete response in the neck. At 9 weeks, contrasted CT showed worsening but nonenhancing ulceration, area biopsied demonstrating a minute carcinoma focus with treatment effect. At 12 weeks, PET/CT showed increased primary site uptake interpreted as disease progression; however, no viable tumor was found at salvage surgery. Because nonenhancing ulceration predicts pure radiation necrosis with no viable tumor, contrasted CT may guide treatment selection in challenging cases.

A Simplified Quantitative Method to Measure Brain Shifts in Patients with Middle Cerebral Artery Stroke.

BACKGROUND AND PURPOSE: A standardized and validated method to measure brain shifts in malignant middle cerebral artery (MCA) stroke with decompressive hemicraniectomy (DHC) could facilitate clinical decision making, prognostication, and comparison of results between studies. METHODS: We tested for reliability simplified methods to measure transcalvarial herniation, midline brain shift, and the contralateral cerebral ventricular atrium in malignant MCA stroke after DHC. Multiple raters measured brain shifts on post-DHC computed tomography (CT) scans with aligned and unaligned slice orientations in 25 patients. We compared the simplified measurements to previously reported more meticulous measurements. RESULTS: The simplified measurements correlate well with the more meticulous measurements on both aligned and unaligned CTs (intraclass correlation coefficients .72-.89). CONCLUSIONS: These simplified and expedient methods of measuring brain shifts in malignant MCA stroke after DHC correlate well with the more meticulous methods.

Folate Deficiency Is Prevalent in Women of Childbearing Age in Belize and Is Negatively Affected by Coexisting Vitamin B-12 Deficiency: Belize National Micronutrient Survey 2011.

Background: Folate deficiency, vitamin B-12 deficiency, and anemia can have adverse effects on birth outcomes. Also, low vitamin B-12 reduces the formation of metabolically active folate.Objectives: We sought to establish the baseline prevalence of and factors associated with folate deficiency and insufficiency, vitamin B-12 deficiency, and anemia among women of childbearing age (WCBA) in Belize.Methods: In 2011, a national probability-based survey was completed among Belizean nonpregnant WCBA aged 15-49 y. Blood samples for determination of hemoglobin, folate (RBC and serum), and vitamin B-12 (plasma) and sociodemographic and health information were collected from 937 women. RBC and serum folate concentrations were measured by microbiologic assay (MBA). Folate status was defined based on both the WHO-recommended radioproteinbinding assay and the assay adjusted for the MBA.Results: The national prevalence estimates for folate deficiency in WCBA, based on serum and RBC folate concentrations by using the assay-matched cutoffs, were 11.0% (95% CI: 8.6%, 14.0%) and 35.1% (95% CI: 31.3%, 39.2%), respectively. By using the assay-matched compared with the WHO-recommended cutoffs, a substantially higher prevalence of folate deficiency was observed based on serum (6.9% absolute difference) and RBC folate (28.9% absolute difference) concentrations. The prevalence for RBC folate insufficiency was 48.9% (95% CI: 44.8%, 53.1%). Prevalence estimates for vitamin B-12 deficiency and marginal deficiency and anemia were 17.2% (95% CI: 14.2%, 20.6%), 33.2% (95% CI: 29.6%, 37.1%), and 22.7% (95% CI: 19.5%, 26.2%), respectively. The adjusted geometric means of the RBC folate concentration increased significantly (P-trend < 0.001) in WCBA who had normal vitamin B-12 status relative to WCBA who were vitamin B-12 deficient.Conclusions: In Belize, the prevalence of folate and vitamin B-12 deficiencies continues to be a public health concern among WCBA. Furthermore, low folate status co-occurred with low vitamin B-12 status, underlining the importance of providing adequate vitamin B-12 and folic acid intake through approaches such as mandatory food fortification.

A standardized method to measure brain shifts with decompressive hemicraniectomy.

BACKGROUND: A standardized, reliable, and practical method for measuring decompressive hemicraniectomy (DHC) defects and brain shifts in malignant middle cerebral artery (MCA) territory infarction is needed for reliable comparisons between computed tomography (CT) scans. Such a method could facilitate further studies on the effects of DHC. NEW METHOD: We describe and apply a method for measuring DHC defects and brain shifts on CT scans in 25 patients with malignant MCA territory infarction. Craniectomy area is adjusted for variations in head size, CT slice orientation is standardized, and the site of each measurement is defined. This method uses standard radiology platforms and volume-acquired helical CT scans. RESULTS: The measurements include a DHC size index (adjusted for variations in head size), midline brain shift (subfalcine), outward brain herniation (transcalvarial), and the diameter of the contralateral atrium of the lateral ventricle. Inter-rater agreement for these measurements in a sample of 15 subjects is excellent (correlation coefficients 0.90-0.98). COMPARISON WITH EXISTING METHODS: In contrast to previously reported methods, this method is tested in acute stroke patients, compensates for variability in head size, and includes a midline brain shift (subfalcine) and brain ventricular system measurements. CONCLUSIONS: A practical method for measuring DHC size and brain shifts designed to be consistent between scans is proposed. This method should facilitate comparisons of measurements between serial scans, between patients, and perhaps between studies. This method could be useful in medical and surgical studies of brain herniations in malignant MCA territory infarction, and possibly other conditions.

Sinonasal Fungal Infections and Complications: A Pictorial Review.

Fungal infections of the nose and paranasal sinuses can be categorized into invasive and non-invasive forms. The clinical presentation and course of the disease is primarily determined by the immune status of the host and can range from harmless or subtle presentations to life threatening complications. Invasive fungal infections are categorized into acute, chronic or chronic granulomatous entities. Immunocompromised patients with poorly controlled diabetes mellitus, HIV and patients receiving chemotherapy or chronic oral corticosteroids are mostly affected. Mycetoma and Allergic Fungal Rhinosinusitis are considered non-invasive forms. Computer tomography is the gold-standard in sinonasal imaging and is complimented by Magnetic resonance imaging (MRI) as it is superior in the evaluation of intraorbital and intracranial extensions. The knowledge and identification of the characteristic imaging patterns in invasive - and non- invasive fungal rhinosinusitis is crucial and the radiologist plays an important role in refining the diagnosis to prevent a possible fatal outcome.

Subtemporal Retrolabyrinthine (Posterior Petrosal) versus Endoscopic Endonasal Approach to the Petroclival Region: An Anatomical and Computed Tomography Study.

Background The petroclival region seats many neoplasms. Traditional surgical corridors to the region can result in unacceptable patient morbidity. The combined subtemporal retrolabyrinthine transpetrosal (posterior petrosal) approach provides adequate exposure with hearing preservation; however, the facial nerve and labyrinth are put at risk. Approaching the petroclival region with an endoscopic endonasal approach (EEA) could minimize morbidity. Objective To provide an anatomical and computed tomography (CT) comparison between the posterior petrosal approach and EEA to the petroclival region. Methods The petroclival region was approached transclivally with EEA. Different aspects of dissection were compared with the posterior petrosal approach. The two approaches were also studied using CT analysis. Results A successful corridor medial to the internal auditory canal (IAC) was achieved with EEA. Wide exposure was achieved with no external skin incisions, although significant sinonasal resection was required. The posterior petrosal was comparable in terms of exposure medially; however, the dissection involved more bone removal, greater skill, and a constricting effect upon deeper dissection. Importantly, access lateral to the IAC was obtained, whereas EEA could not reach this area. Conclusion An EEA to the petroclival region is feasible. This approach can be considered in lesions medial to the IAC.

Parálisis del nervio abducens secundario a meningioma del canal de Dorello: Consideraciones anatómicas por resonancia magnética / Abducens nerve palsy secondary to Dorello’ s canal meningioma: MRI anatomical considerations

La parálisis de los músculos oculomotores comprende una patología muy variada, producida por lesiones en varios niveles (desde la corteza cerebral hasta la placa neuromuscular) que debe ser estudiada de manera exhaustiva para poder encontrar la causa etiológica exacta y definir un manejo adecuado. La inervación motora del ojo humano es producida por los pares craneales III, IV y VI, que coordinan movimientos específicos del globo ocular hacia el objeto de atención del campo visual, permitiendo que las imágenes percibidas en la retina y transmitidas a través del nervio óptico se fusionen en una sola en la corteza visual cerebral. En este artículo, nos enfocaremos en la parálisis del nervio abducens, apoyándonos en un caso de una paciente de 50 años de edad, quien consultó por diplopía izquierda como único síntoma, y a quien se le diagnosticó un meningioma del canal de Dorello. Además haremos una correlación anatómica del VI par craneal, desde su origen hasta alcanzar el músculo recto lateral, su fisiología y el tipo de lesiones que lo pueden afectar, en especial los meningiomas, su comportamiento y las características en imágenes diagnósticas.

Palsy of the extra ocular muscles can result from several diseases affecting cranial nerves at various levels from the cerebral cortex to the neuromuscular junction. These levels must be studied exhaustively to define the exact etiology to determine appropriate management. The motor function of the human eye is produced by cranial nerves III, IV and VI, which coordinate bilateral globe movements to focus attention in an object within the visual field, allowing for images perceived in the retina and transmitted by the optic nerves to be integrated in the cerebral visual cortex. In this article, we will focus on Abducens nerve palsy exemplified by the case of a 50 year old woman with left diplopia as the only presenting symptom, found to have a meningioma in Dorello’s canal. We will emphasize the anatomic correlation of the sixth cranial nerve, from its origins up to the lateral rectus muscle, its physiology and the type of injuries affecting it, especially meningiomas and their features in diagnostic imaging.

Computed Tomographic Exploration of the Middle Ethmoidal Artery.

Objectives The integral involvement of sinus and skull base surgeries in the field of otolaryngology makes the endonasal vasculature including the ethmoidal arteries important to consider. The anterior ethmoidal artery (AEA) and posterior ethmoidal artery (PEA) are well-known entities, yet the relatively recent notion of accessory or middle ethmoidal vessels complicates our understanding of this arterial system. Study Design Radiographic study. Methods Fifty computed tomographic angiographies were studied for the presence of accessory/middle ethmoidal arteries (MEAs). If contrasted arteries were not visualized reliably, foramina were accepted as evidence of arteries. The accessory arteries/foramina were then compared with the locations of the AEA and PEA. Results A total of 19 of the 50 patient samples studied had evidence of a right, left, or bilateral middle ethmoidal vessels (38%). Overall, 26 arteries total were identified out of the 100 sides (26%). Unilateral middle arteries were more common than bilateral, and right sided were more common than left. There was no evidence of multiple MEAs on a given side. Conclusion The endonasal surgeon must be cognizant of the possible presence of MEAs. These arteries should be considered when working in the medial orbit and anterior skull base region.

Primary intracranial mucosa-associated lymphoid tissue lymphoma. A report of two cases and literature review.

Low-grade B cell non-Hodgkin lymphomas typically arise from the marginal zone of the secondary lymphatic follicles. Their intracranial expression is very rare, most frequently affecting the dura mater and the choroid plexus glomi in the lateral ventricles. Their initial evaluation requires the exclusion of more common extra-axial lesions, such as meningiomas, dural metastasis, granulomatous lesions or secondary lymphoproliferative dural extension from body lymphomas. Whenever a ventricular lesion is present, the patient's age and lesion location help narrow the differential diagnosis. Dural-based lymphomas and ventricular/choroid plexus lymphomas are slow-growing lesions with imaging features similar to meningiomas, which is typically their main differential consideration. Diffusion-weighted images frequently show restricted diffusion behaviour on lymphomas, helping to differentiate them from the typical meningiomas.

Central nervous system tuberculosis.

Tuberculosis (TB) has shown a resurgence in nonendemic populations in recent years and accounts for 8 million deaths annually in the world. Central nervous system involvement is one of the most serious forms of this infection, acting as a prominent cause of morbidity and mortality in developing countries. The rising number of cases in developed countries is mostly attributed to factors such as the pandemic of acquired immunodeficiency syndrome and increased migration in a globalized world. Mycobacterium TB is responsible for almost all cases of tubercular infection in the central nervous system. It can manifest in a variety of forms as tuberculous meningitis, tuberculoma, and tubercular abscess. Spinal infection may result in spondylitis, arachnoiditis, and/or focal intramedullary tuberculomas. Timely diagnosis of central nervous system TB is paramount for the early institution of appropriate therapy, because delayed treatment is associated with severe morbidity and mortality. It is therefore important that physicians and radiologists understand the characteristic patterns, distribution, and imaging manifestations of TB in the central nervous system. Magnetic resonance imaging is considered the imaging modality of choice for the study of patients with suspected TB. Advanced imaging techniques including magnetic resonance perfusion and diffusion tensor imaging may be of value in the objective assessment of therapy and to guide the physician in the modulation of therapy in these patients.

Analysis of the petrous portion of the internal carotid artery: landmarks for an endoscopic endonasal approach.

OBJECTIVES/HYPOTHESIS: While there are many benefits to the endoscopic endonasal approach to the infratemporal fossa, involvement of the petrous portion of the internal carotid artery (ICA) poses a unique challenge. The endoscopic endonasal approach requires establishing the relationship of the petrous ICA to anatomical landmarks to guide the surgeon. This study evaluates the relationship of petrous ICA to specific anatomic landmarks, both radiographically and through cadaveric dissections. STUDY DESIGN: Cadaveric and radiographic study. METHODS: An endoscopic endonasal approach was used to access the petrous carotid and infratemporal fossa. Dissections exposed the petrous portion of the carotid artery and identified the foramen rotundum, ovale, and spinosum. Both anatomical and radiographic representations of these landmarks were then evaluated and compared relative to the petrous carotid. RESULTS: The endoscopic endonasal approach to the infratemporal fossa with exposure of the petrous ICA afforded complete visualization of the entire segment of this portion of the ICA with limited anatomical obstruction. The foramen rotundum, ovale, and spinosum were successfully identified and dissected with preservation of their neuro/vascular contents. Computed tomography analysis calculated a mean distance to the petrous ICA of 16.34 mm from the foramen rotundum, 4.88 mm from the ovale, and 5.11 mm from the spinosum in males. For females, the values were 16.40 mm from the rotundum and 4.36 mm each from the ovale and spinosum. CONCLUSION: An endonasal endoscopic approach to the infratemporal fossa with exposure of the petrous ICA is feasible. The anatomical landmarks can serve as both radiographic and surgical landmarks in this approach.

Landmarks for endoscopic approach to the parapharyngeal internal carotid artery: a radiographic and cadaveric study.

OBJECTIVES/HYPOTHESIS: To define transnasal endoscopic surgical landmarks for the parapharyngeal segment of the internal carotid artery (ppICA) using radiographic analysis and cadaveric dissection. STUDY DESIGN: Cadaveric and radiographic study. METHODS: One hundred seventy-nine computed tomography angiography studies of the head and neck were analyzed using Osirix third-party software (Pixmeo, Geneva, Switzerland). Dissection of a cadaveric specimen was used as a correlate to radiographic findings. The posterior aspect of the lateral pterygoid process and posterior border of the mandibular ramus were used as bony landmarks for the ppICA. RESULTS: At the level of the nasal floor, the distance from the ppICA to the posterolateral pterygoid process and to the posterior mandibular ramus was 2.36 cm and 1.94 cm, respectively, in males, and 2.37 cm and 1.99 cm, respectively, in females. At the level of the skull base, the distance from the ppICA to the posterolateral pterygoid process and to the posterior mandible was 2.33 cm and 1.49 cm, respectively, in males, and 2.20 cm and 1.57 cm, respectively, in females. Cadaver dissection demonstrated the utility of identifying these landmarks. CONCLUSIONS: The posterior border of the mandibular ramus and the posterolateral aspect of the pterygoid process may serve as consistent bony landmarks for identification of the ppICA.

Cerebral vascular malformations in hereditary hemorrhagic telangiectasia.

OBJECT: Hereditary hemorrhagic telangiectasia (HHT) is a hereditary disorder characterized by mucocutaneous telangiectasias, frequent nosebleeds, and visceral arteriovenous malformations (AVMs). Few reports have outlined the prevalence of the various cerebral vascular malformations found in patients with HHT. The authors set out to define the prevalence of cerebral vascular malformations in a population of HHT patients who underwent imaging with 3-T imaging (MRI/MR angiography [MRA]) of the brain. METHODS: A retrospective review of prospectively collected data was carried out using a database of 372 HHT patients who were seen and examined at the Georgia Regents University HHT Center and screened with 3-T MRI/MRA. Data were tabulated for numbers and types of vascular malformations in this population. RESULTS: Arteriovenous malformations were identified in 7.7%, developmental venous anomalies in 4.3%, and cerebral aneurysms in 2.4% of HHT patients. The HHT AVMs tended to be supratentorial, small, and cortical in this series, findings consistent with other recent studies in the literature. An arteriovenous fistula, cavernous malformation, and capillary telangiectasia were identified in 0.5%, 1%, and 1.9% of HHT patients, respectively. CONCLUSIONS: Few studies have investigated the prevalence of the various vascular malformations found in HHT patients screened with 3-T MRI/MRA of the brain. Hereditary hemorrhagic telangiectasia AVMs are more likely to be multiple and have a tendency toward small size and cortical location. As such, they are often treated using a single-modality therapy.

Embolic Stroke Diagnosed by Elevated D-Dimer in a Patient With Negative TEE for Cardioembolic Source.

We report a case of cerebrovascular accident with thromboembolic stroke etiology in a patient who had atrial flutter and negative transesophageal echocardiography (TEE) results. The increased D-dimer levels (1877 ng/mL) initiated referral for magnetic resonance imaging and magnetic resonance angiography of the brain that showed classic recanalization of an embolic thrombus in the angular branch of the left middle cerebral distribution. The D-dimer level of this patient was normalized after 3 months of anticoagulation therapy. Although TEE is considered the gold standard for evaluation of cardiac source of embolism, exclusion of intracardiac thrombus with TEE alone does not eliminate the risk of thromboembolic events. This case highlights the utility of D-dimer as a potential adjunct in the decision-making process to guide investigation of thromboembolism, determine subsequent therapy, and hence reduce the risk of embolic stroke recurrence.

A preliminary assessment of financial stability, efficiency, health systems and health outcomes using performance-based contracts in Belize.

Over the last 10 years, Belize has implemented a National Health Insurance (NHI) program that uses performance-based contracts with both public and private facilities to improve financial sustainability, efficiency and service provision. Data were collected at the facility, district and national levels in order to assess trends in financial sustainability, efficiency payments, year-end bonuses and health system and health outcomes. A difference-in-difference approach was used to assess the difference in technical efficiency between private and public facilities. The results show that per capita spending on services provided by the NHI program has decreased over the period 2006-2009 from BZ$177 to BZ$136. The private sector has achieved higher levels of technical efficiency, but lower percentages of efficiency and year-end bonus payments. Districts with contracts through the NHI program showed greater improvements in facility births, nurse density, reducing maternal mortality, diabetes deaths and morbidity from bronchitis, emphysema and asthma than districts without contracts over the period 2006-2010. This preliminary assessment of Belize's pay-for-performance system provides some positive results, however further research is needed to use the lessons learned from Belize to implement similar reforms in other systems.

Dural-based metastatic carcinomas mimicking primary CNS neoplasia: report of 7 cases emphasizing the role of timely surgery and accurate pathologic evaluation.

Clinical presentation with dural-based metastasis mimicking meningiomas is rare. We aimed to evaluate the role of frozen section in guiding surgery and histopathologic diagnosis in determining primary sites of dural-based metastatic carcinomas. Following the receipt of HAC approval, we retrospectively reviewed 7cases presenting with dural-based masses clinically suspected to be primary brain tumors (6 meningiomas and 1 superficial glioblastoma), but diagnosed to be metastatic carcinomas on subsequent resection. Pertinent clinical records and follow-up data were reviewed. Patient's age ranged from 59 to 80 years. Imaging showed extra-axial dural-based masses with contiguous but not primary brain involvement. On intra-operative frozen section (not performed in case 7), differential diagnoses included metastatic carcinoma in all cases, and surgery modified accordingly. Nesting, cribriform, and "picket-fence" like glands were among useful histologic diagnostic patterns. Immunoprofile supported histologic diagnosis in all cases. Subsequent clinical and radiologic evaluation confirmed coexistent sites of origin in all cases. The metastases were solitary in all cases; except multiple dural-based tumors in case 1, in which interestingly no systemic metastasis were identified. Dural-based metastatic carcinomas mimicking meningiomas may be solitary, of unknown primary, or without concomitant systemic spread on imaging. Frozen section evaluation is helpful in modifying surgery. Although high-grade, these are typically differentiated enough to allow accurate histopathologic diagnosis, and reasonable determination of primary tumor site, especially with a judicious panel of cytokeratins, transcription factors, hormone receptors and relatively organ-specific markers. Clinicians and pathologists need to be aware of the occurrence, spectrum, need for timely intervention, and accurate diagnosis of dural-based metastatic carcinomas.

Quantitative analysis of endoscopic endonasal approaches to the infratemporal fossa.

OBJECTIVES/HYPOTHESIS: The operative management of infratemporal skull base lesions is challenging. Expanded endonasal approaches to this area can decrease surgical morbidity. Access lateral to the natural nasal corridor can be achieved via a middle meatal antrostomy, medial maxillectomy complemented by a septotomy, or anteromedial maxillotomy (i.e., Denker's approach). We sought to compare the access to the infratemporal fossa offered by these endoscopic endonasal approaches. STUDY DESIGN: Software-enabled CT scan measurements. METHODS: Axial CT scans obtained with submillimeter cuts through the skull base were examined. All calculations were performed on axial images obtained at the level of the sphenoid floor using Kodak Carestream Image Software (Rochester, NY) measuring tools. RESULTS: Fifty sides were examined. A medial maxillectomy increased the exposure on average by 18.5 degrees (SD = 4.28), when compared to maxillary antrostomy. When we augmented the access with an ipsilateral Denker's approach, an additional 33.5 degrees (SD = 4.81) of exposure were obtained (P < .0001). The addition of a 1-cm anteromedial maxillotomy accessed the entire posterior maxillary wall in 54% of cases. Equivalent access was obtained via a contralateral approach with a septotomy at 1.56 cm from the columella. To access the entire posterior maxillary wall the average anterior maxillotomy should be 1.1 cm (SD = 0.42). In contrast, to access the entire posterior maxillary wall using a contralateral approach the average septotomy position should be 1.52 cm (SD = 0.39) from the columella. CONCLUSIONS: This radioanatomic study provides objective support for the use of an ipsilateral Denker's approach to augment an endoscopic endonasal approach to the infratemporal fossa.

Cochlear implantation using thin-film array electrodes.

OBJECTIVE: Current limitations in language perception may stem from an inability to provide high-resolution sound input. Thin-film array technology allows for a greater density of stimulating sites within the limited diameter of the scala tympani. This study examines the use of a flexible carrier to achieve adequate depth of insertion. STUDY DESIGN: A prospective human cadaveric temporal bone insertion analysis. SETTING: Academic otolaryngology department and school of electrical and computer engineering collaboration. METHODS: A prototype thin-film array electrode coupled with an insertion test device (ITD) was manufactured and inserted into 10 human cadaveric temporal bones. As controls, 2 additional temporal bones were implanted with the ITD only and 2 were unimplanted. Radiologic and histologic data were collected. RESULTS: Ten thin-film array electrodes were successfully implanted into 10 individual temporal bones via round window (5) and cochleostomy (5) approaches. Seventeen millimeters of insertion was noted for each device, with an average angular insertion depth of 292° by radiographic measurements and 392° by histologic sectioning. Electrode distance to the modiolus averaged 0.88 mm by computed tomography and 0.67 mm by histologic measurements. Average percentage trauma was 26% for the ITD-backed arrays compared with 15% and 29% for ITD only and unimplanted temporal bones, respectively. CONCLUSION: Thin-film array electrodes coupled with an ITD were successfully inserted into the human cochlea with limited trauma. With continued development and testing of this electrode design, the thin-film array may improve the language perception achieved through cochlear implantation.

Estenosis del canal auditivo interno (CAI): hallazgos por imagen / Internal auditory canal (IAC) stenosis: imaging findings

Objetivos: Describir los hallazgos por imagen en tomografía computarizada (TAC ) y resonancia magnética (RM) en una paciente con estenosis del CAI. Describir el desarrollo embriológico de las estructuras del CAI y la historia natural de la estenosis del CAI . Métodos: Se presenta el caso de una paciente de 4 años de edad con diagnóstico de cardiopatía congénita, hipoacusia neurosensorial (HNS ) y otitis media recurrente bilateral, y a quien se realizó TAC del hueso temporal con imágenes axiales y reconstrucciones coronales, en las cuales se observa disminución del diámetro de la luz del CAI izquierdo (menor de 2 mm), ausencia del CAI derecho y estructuras del oído interno de características normales, compatibles con estenosis del CAI izquierdo. Las imágenes de RM demuestran la estenosis del CAI izquierdo, sin observarse las estructuras nerviosas dentro de éste, compatible con hipoplasia/aplasia del nervio vestibulococlear. Resultados: Se describen brevemente la patología, el origen embriológico y la importancia de la asociación de la estenosis delCAI a hipoplasia/aplasia del nervio vestibulococlear en el diagnóstico diferencial de las causas de HNS , que contraindican la realización de implante coclear. Conclusiones: La estenosis del CAI e hipoplasia/aplasia del nervio vestibulococlear es un diagnóstico para tener en cuenta dentro de las causas de HNS , y su diagnóstico puede realizarse a través de TAC y de RM.

Objectives: To describe the computed tomography (CT) and magnetic resonance (MR) findings in a patient with a diagnosis of internal auditory canal (IAC) stenosis. To describe the embryological development of the IAC structures and the natural history of IAC stenosis. Methods: A 4 year old girl presents with sensorineural hearing loss and bilateral recurrent otitis media. The temporal bone CT shows diminished left IAC diameter (less than 2 mm),right IAC absence and normal inner ear structures. These findings are pathognomonic for left IAC stenosis. The MR findings include left IAC stenosis and IAC neural structures absence secondary to aplasia of the vestibulocochlear nerve on each IAC . Results: Hypoplasia/aplasia of the vestibulocochlear nerve in association with IAC stenosis is an important consideration in the differential diagnosis of sensorineural hearing loss, as it is a relative contraindication for cochlear implant placement. Conclusions: IAC stenosis and vestibulocochlear nerve hypoplasia/aplasia must be excluded as an etiology of sensorineural hearing loss. The diagnosis can be made by CT and MR.