RESUMO
The objective of this study was to evaluate the characteristic symptoms of and treatments for lateral semicircular canal dehiscence (LSCD) and posterior semicircular canal dehiscence (PSCD) and its proposed mechanism. A dehiscence acquired in any of the semicircular canals may evoke various auditory symptoms (autophony and inner ear conductive hearing loss) or vestibular symptoms (vertigo, the Tullio phenomenon, and Hennebert sign) by creating a "third mobile window" in the bone that enables aberrant communication between the inner ear and nearby structures. A PubMed search was performed using the keywords lateral, posterior, and semicircular canal dehiscence to identify all relevant cases. Our data suggest that PSCD, although clinically rare, is most likely associated with a high-riding jugular bulb and fibrous dysplasia. Patients may experience auditory manifestations that range from mild conductive to extensive sensorineural hearing loss. LSCD is usually associated with chronic otitis media with cholesteatoma.
RESUMO
Ependymomas are tumors that can present within either the intracranial or spinal regions. While 90% of all pediatric ependymomas are intracranial, spinal cord ependymomas are more commonly found in patients 20-40 years old. Treatment for spinal lesions has achieved local control rates up to 100% following gross total resection, while pediatric intracranial tumors have 40-60% mortality. Given the inability to effectively treat ependymomas with current standard practices, researchers have focused their efforts on evaluating chromosomal alterations, genetic expression profiles, epigenetic events, and molecular pathways. While these studies have provided critical insight into the potential mechanisms underlying ependymoma pathogenesis, understanding of the intricate interplay between the various pathways involved in tumor initiation, development, and progression will require deeper investigation. However, several potential prognostic markers and therapeutic targets have been identified, providing key areas of focus for future research. The utilization of unique genetic expression profiles based upon patient age, tumor location, tumor grade, and subtype has revealed a multitude of findings warranting further study. Inspection of various molecular pathways associated with ependymomas may establish the foundation for developing novel therapies capable of achieving significant clinical improvements with individualized regimens specifically designed for personalized treatment strategies.
Assuntos
Neoplasias do Sistema Nervoso Central/genética , Neoplasias do Sistema Nervoso Central/terapia , Ependimoma/genética , Ependimoma/terapia , Adulto , Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Criança , Impressões Digitais de DNA , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Redes e Vias Metabólicas , Prognóstico , Neoplasias da Coluna Vertebral/genética , Neoplasias da Coluna Vertebral/terapiaRESUMO
Objectives To review the characteristic symptoms of superior semicircular canal dehiscence, testing and imaging of the disease, and the current treatment and surgical options. Results and Conclusions Symptoms of superior semicircular canal dehiscence (SSCD) include autophony, inner ear conductive hearing loss, Hennebert sign, and sound-induced episodic vertigo and disequilibrium (Tullio phenomenon), among others. Potential etiologies noted for canal dehiscence include possible developmental abnormalities, congenital defects, chronic otitis media with cholesteatoma, fibrous dysplasia, and high-riding jugular bulb. Computed tomography (CT), vestibular evoked myogenic potentials, Valsalva maneuvers, and certain auditory testing may prove useful in the detection and evaluation of dehiscence syndrome. Multislice temporal bone CT examinations are normally performed with fine-cut (0.5- to 0.6-mm) collimation reformatted to the plane of the superior canal such that images are parallel and orthogonal to the plane. For the successful alleviation of auditory and vestibular symptoms, a bony dehiscence can be surgically resurfaced, plugged, or capped through a middle fossa craniotomy or the transmastoid approach. SSCD should only be surgically treated in patients who exhibit clinical manifestations.
