Temporal Bone
Hearing Loss, Conductive
Ear, Middle
Audiometry, Pure-Tone
Mastoiditis
Meniere Disease
Surgical Procedures, Operative
Ear, Inner
Hearing Loss
Spatiotemporal dynamics of brain-derived neurotrophic factor mRNA induction in the vestibulo-olivary network during vestibular compensation. (1/56)
Vestibular compensation, which is the behavioral recovery from vestibular dysfunction produced by unilateral labyrinthectomy (UL), is attributed to functional and structural reorganization of neural networks in the central vestibular system. To assess the possible contribution of brain-derived neurotrophic factor (BDNF) to this recovery process, we investigated changes in mRNA expression levels in the central vestibular system after UL. We evaluated BDNF mRNA expression levels by quantitative reverse transcription-PCR and in situ hybridization. We found that BDNF mRNA is differentially induced in the medial vestibular nucleus ipsilateral to UL and in the prepositus hypoglossi and inferior olive on the contralateral side. The BDNF mRNA induction lasted for at least 24 hr and returned to the basal expression level within 72 hr after UL. In contrast to BDNF mRNA induction, the expression of an immediate-early gene, c-fos, quickly reached the maximum level at 3 hr and decreased to the basal level within 24 hr after UL. Neither BDNF or c-fos induction was observed in sham-operated animals. The persistent induction of BDNF after UL temporally corresponded to early behavioral manifestations of vestibular compensation. We further found that trkB mRNA was expressed in the central vestibular network at high levels, although its expression levels did not change over time after UL. Because BDNF is implicated in regulating synaptic structure and function, these results provide support for the hypothesis that BDNF is involved in neuronal reorganization that allows vestibular compensation. (+info)Prognostic significance of changes in the internal acoustic meatus caused by vestibular schwannoma. (2/56)
The prognostic significance of the variety of changes in the internal auditory meatus (IAM) caused by vestibular schwannoma was retrospectively analyzed in 69 consecutive patients with vestibular schwannoma. Preoperative bone-window computed tomography was used to classify IAM changes into extensive destruction (17%), widening (46%), and normal IAM (36%). Extensive destruction (47 +/- 19 years) and widening (48 +/- 13) occurred in significantly younger patients than normal IAM (59 +/- 9). Preoperative hearing was significantly more severely disturbed in patients with extensive destruction than in those with widening or normal IAM. IAM change was significantly related to the tumor consistency, as normal IAM was more common in patients with cystic tumor than in those with solid tumor. Postoperative hearing and facial function were worse in patients with severe IAM change, although the relationship between the IAM change and the surgical result was not significant. One patient with extensive destruction developed postoperative cerebrospinal fluid (CSF) leakage through the air cells around the IAM, and needed surgical repair. Severe IAM change occurs with solid tumor and causes severely disturbed preoperative hearing in younger patients, which reflects the tumor aggressiveness. Severe IAM change increases the technical difficulty of tumor removal and the risk of postoperative CSF leakage, and is associated with a poorer prognosis for patients with vestibular schwannoma. (+info)Unilateral labyrinthectomy modifies the membrane properties of contralesional vestibular neurons. (3/56)
Vestibular compensation after a unilateral labyrinthectomy leads to nearly complete disappearance of the static symptoms triggered by the lesion. However, the dynamic vestibular reflexes associated with head movements remain impaired. Because the contralesional labyrinth plays a prominent role in the generation of these dynamic responses, intracellular recordings of contralesional medial vestibular nucleus neurons (MVNn) were done after 1 mo of compensation. Their firing properties and cell type were characterized at rest, and their response dynamics investigated using step, ramp, and sinusoidal current stimulations. The sensitivity of the contralesional MVNn firing rates to applied current was increased, which, along with increased phase leads, suggests that significant changes in active conductances occurred. We found an increased proportion of the phasic type B neurons relative to the tonic type A neurons in the contralesional MVN. In addition, the remaining contralesional type A MVNn response dynamics tended to approach those of type B MVNn. Thus the contralesional MVNn in general showed more phasic response dynamics than those of control MVNn. Altogether, the firing properties of MVNn are differentially modified on the ipsilesional and contralesional sides of the brain stem 1 mo after unilateral labyrinthectomy. Ipsilesional MVNn acquire more "type A-like" tonic membrane properties, which would contribute to the stabilization of the spontaneous activity that recovers in the deafferented neurons during vestibular compensation. The bilateral increase in the sensitivity of MVNn and the acquisition of more "B-like" phasic membrane properties by contralesional MVNn should promote the restoration of the vestibular reflexes generated by the remaining, contralesional labyrinth. (+info)Microscopic anatomy of the carotid canal and its relations with cochlea and middle ear. (4/56)
The knowledge of the relations between the noble and vital structures of temporal bone is still a great challenge for the otologic surgeon. The microscopic anatomic studies of the temporal bone are one of the greatest help to prevent lesions during surgical intervention. AIM: To study the anatomic correlations between the carotid canal and the cochlea, and the occurrence of dehiscence of the carotid canal in the middle ear tympanic cavity. MATERIAL AND METHODS: Microscopic study of 122 human temporal bones. RESULTS: The average distance between the carotid canal and the cochlea were: the shortest distance, 1.05 mm; basal turn, 2.04 mm; middle turn, 2.32 mm; and apical turn, 5.70 mm. The occurrence of dehiscence of the carotid canal inside the tympanic cavity was 35.2%. CONCLUSION: The small distances between the cochlea and carotid canal, and the high incidence of dehiscence in the tympanic cavity remind us that anatomical knowledge of the temporal bone is required for the best qualification of otologists. (+info)The translabyrinthine approach for acoustic neuroma and its common complications. (5/56)
A retrospective analysis of 15 cases intracanalicular acoustic neuroma that undergone tumour excision by translabyrinthine approach spanning from August 1996 until December 2002 is presented. The main presenting complaints are unilateral hearing loss (100%) and tinnitus (86.7%). The mean age of presentation was 48.5 years old. Magnetic resonance imaging is the most important investigation tool to diagnose acoustic neuroma. At six months post operatively, the facial nerve was normal or near normal (grade I and II) in 46.6%, grade III to IV in 46.6% and grade V to VI in 6.7% of the cases respectively. There were also four cases of post operative cerebrospinal fluid leak, which was successfully managed with conservative measures. The translabyrinthine approach is the most familiar surgical technique employed by otologist. It is the most direct route to the cerebellopontine angle and internal auditory canal. It requires minimum cerebellar retraction. However, it sacrifices any residual hearing in the operated ear. (+info)Canal wall reconstruction and mastoid obliteration with composite multi-fractured osteoperiosteal flap. (6/56)
We used inferior pedicled composite multi-fractured osteoperiosteal flap (CMOF), our original and new surgical approach, to obliterate the mastoid cavity and reconstruct the external auditory canal (EAC) to prevent the open cavity problems. CMOF was used to obliterate the mastoid cavity and reconstruct the EAC in 24 patients (13 women, 11 men; age span 12-51 years) who underwent radical mastoidectomy to treat the chronic otitis media between 1998 and 2004. Small meatoplasty was done in all 24 patients to relieve their aesthetical concerns. Temporal bone CT scanning was done to observe the neo-osteogenesis in the mastoidectomy cavity and the CMOF, and the EAC volume was measured postoperatively. All our patients were followed-up for 2 years. The epithelization of the new EAC in our patients was complete at the end of the second month. Cholesteatoma, granulation, and recurrence of osteitis did not occur in any of the patients. We saw the new bone formation filling the mastoid cavity in the postoperative temporal bone CT scanning images. The mean volume of the new EAC on the 24th month was 1.83 +/- 0.56 cm(3). We had an almost natural EAC, which owed its existence to the neo-osteogenesis that grows behind the CMOF, which we use to obliterate the mastoid cavity and to reconstruct the EAC. (+info)The mastoid as a functional rate-limiter of middle ear pressure change. (7/56)
INTRODUCTION: The physiological function of the mastoid air cell system (MACS) with respect to middle ear (ME) pressure-regulation remains controversial because predictive mathematical models and experimental data to formulate and test hypotheses are lacking. OBJECTIVE: A mathematical description of MACS volume effects on the rate of ME pressure change is presented; the agreement between published data and model prediction is examined for consistency with the hypothesis that the MACS acts as a functional rate-limiter of ME pressure change, and an explanation for the relationship between MACS volume and otitis media is discussed. METHODS: The mathematical description shows that the value of a single, free parameter, termed the "MACS buffering efficiency" (M) determines if MACS volume affects the rate of ME pressure change caused by diffusive gas exchange. The MACS serves no rate-limiting function for M=0, acts as a gas sink for M>1 and acts as a gas reserve (rate-limiter) for M<1. RESULTS: Fitting the model equation to published adult human data yielded an estimate for M of 0.2. This implies that larger MACS volumes are associated with lesser rates of change in ME pressure caused by diffusive gas exchange and lesser required frequencies of effective Eustachian tube openings to maintain near ambient ME pressures. CONCLUSION: If well-controlled studies confirm M<1 for children and adults, larger MACS volumes will increase the time required to develop sufficient ME underpressures to cause otitis media by hydrops ex vacuo during transient or prolonged periods of Eustachian tube dysfunction. (+info)Comparison of microtia reconstructive surgery with autograft versus homograft. (8/56)
BACKGROUND: Microtia is a congenital abnormality with low incidence but considerable morbidities. Reconstruction of the microtia deformity is a complex and difficult process that requires a proper planning. The primary technique of reconstruction employs patient's own rib cartilage. Irradiated homograft cartilages previously have been used in facial reconstruction but its application in microtia surgery has not been reported yet. This study is designed to compare the results of autograft versus homograft auriculoplasty. METHODS: Between 1992 - 2002, 23 patients underwent auricular reconstructive surgery by the senior author in our department. Autograft implantation was performed in one stage but homograft auriculoplasty was done in two stages. RESULTS: Auricular deformity was right-sided in 13, left-sided in 8, and bilateral in 2 cases. Implanted graft was autograft in 9 patients and homograft in 14 patients. During mean follow-up of 4 years, cartilage graft resorption was detected in two cases, one in autograft and one in homograft group (P > 0.05). No postoperative infection was observed. Status of postauricular sulcus was optimal in 85.7% of homograft and 77.8% of autograft groups (P > 0.05). The satisfaction score of the patients and/or parents was excellent in 66.7% of autograft and 92.9% of homograft groups (P < 0.01). CONCLUSION: Based on better satisfaction score, equivalent aesthetic appearance, and absence of complications such as scaring and pain on the chest wall, homograft auriculoplasty is an appropriate option for reconstructive surgery in patients with microtia. (+info)Otologic surgical procedures refer to a range of surgeries performed on the ear or its related structures. These procedures are typically conducted by otologists, who are specialists trained in diagnosing and treating conditions that affect the ears, balance system, and related nerves. The goal of otologic surgery can vary from repairing damaged bones in the middle ear to managing hearing loss, tumors, or chronic infections. Some common otologic surgical procedures include:
1. Stapedectomy/Stapedotomy: These are procedures used to treat otosclerosis, a condition where the stapes bone in the middle ear becomes fixed and causes conductive hearing loss. The surgeon creates an opening in the stapes footplate (stapedotomy) or removes the entire stapes bone (stapedectomy) and replaces it with a prosthetic device to improve sound conduction.
2. Myringoplasty/Tympanoplasty: These are surgeries aimed at repairing damaged eardrums (tympanic membrane). A myringoplasty involves grafting a piece of tissue over the perforation in the eardrum, while a tympanoplasty includes both eardrum repair and reconstruction of the middle ear bones if necessary.
3. Mastoidectomy: This procedure involves removing the mastoid air cells, which are located in the bony prominence behind the ear. A mastoidectomy is often performed to treat chronic mastoiditis, cholesteatoma, or complications from middle ear infections.
4. Ossiculoplasty: This procedure aims to reconstruct and improve the function of the ossicles (middle ear bones) when they are damaged due to various reasons such as infection, trauma, or congenital conditions. The surgeon uses prosthetic devices made from plastic, metal, or even bone to replace or support the damaged ossicles.
5. Cochlear implantation: This is a surgical procedure that involves placing an electronic device inside the inner ear to help individuals with severe to profound hearing loss. The implant consists of an external processor and internal components that directly stimulate the auditory nerve, bypassing the damaged hair cells in the cochlea.
6. Labyrinthectomy: This procedure involves removing the balance-sensing structures (vestibular system) inside the inner ear to treat severe vertigo or dizziness caused by conditions like Meniere's disease when other treatments have failed.
7. Acoustic neuroma removal: An acoustic neuroma is a benign tumor that grows on the vestibulocochlear nerve, which connects the inner ear to the brain. Surgical removal of the tumor is necessary to prevent hearing loss, balance problems, and potential neurological complications.
These are just a few examples of the various surgical procedures performed by otolaryngologists (ear, nose, and throat specialists) to treat conditions affecting the ear and surrounding structures. Each procedure has its specific indications, benefits, risks, and postoperative care requirements. Patients should consult with their healthcare providers to discuss the most appropriate treatment options for their individual needs.
Ear diseases are medical conditions that affect the ear and its various components, including the outer ear, middle ear, and inner ear. These diseases can cause a range of symptoms, such as hearing loss, tinnitus (ringing in the ears), vertigo (dizziness), ear pain, and discharge. Some common ear diseases include:
1. Otitis externa (swimmer's ear) - an infection or inflammation of the outer ear and ear canal.
2. Otitis media - an infection or inflammation of the middle ear, often caused by a cold or flu.
3. Cholesteatoma - a skin growth that develops in the middle ear behind the eardrum.
4. Meniere's disease - a disorder of the inner ear that can cause vertigo, hearing loss, and tinnitus.
5. Temporomandibular joint (TMJ) disorders - problems with the joint that connects the jawbone to the skull, which can cause ear pain and other symptoms.
6. Acoustic neuroma - a noncancerous tumor that grows on the nerve that connects the inner ear to the brain.
7. Presbycusis - age-related hearing loss.
Treatment for ear diseases varies depending on the specific condition and its severity. It may include medication, surgery, or other therapies. If you are experiencing symptoms of an ear disease, it is important to seek medical attention from a healthcare professional, such as an otolaryngologist (ear, nose, and throat specialist).
The temporal bone is a paired bone that is located on each side of the skull, forming part of the lateral and inferior walls of the cranial cavity. It is one of the most complex bones in the human body and has several important structures associated with it. The main functions of the temporal bone include protecting the middle and inner ear, providing attachment for various muscles of the head and neck, and forming part of the base of the skull.
The temporal bone is divided into several parts, including the squamous part, the petrous part, the tympanic part, and the styloid process. The squamous part forms the lateral portion of the temporal bone and articulates with the parietal bone. The petrous part is the most medial and superior portion of the temporal bone and contains the inner ear and the semicircular canals. The tympanic part forms the lower and anterior portions of the temporal bone and includes the external auditory meatus or ear canal. The styloid process is a long, slender projection that extends downward from the inferior aspect of the temporal bone and serves as an attachment site for various muscles and ligaments.
The temporal bone plays a crucial role in hearing and balance, as it contains the structures of the middle and inner ear, including the oval window, round window, cochlea, vestibule, and semicircular canals. The stapes bone, one of the three bones in the middle ear, is entirely encased within the petrous portion of the temporal bone. Additionally, the temporal bone contains important structures for facial expression and sensation, including the facial nerve, which exits the skull through the stylomastoid foramen, a small opening in the temporal bone.
The mastoid is a term used in anatomy and refers to the bony prominence located at the base of the skull, posterior to the ear. More specifically, it's part of the temporal bone, one of the bones that forms the side and base of the skull. The mastoid process provides attachment for various muscles involved in chewing and moving the head.
In a medical context, "mastoid" can also refer to conditions or procedures related to this area. For example, mastoiditis is an infection of the mastoid process, while a mastoidectomy is a surgical procedure that involves removing part or all of the mastoid process.
Conductive hearing loss is a type of hearing loss that occurs when there is a problem with the outer or middle ear. Sound waves are not able to transmit efficiently through the ear canal to the eardrum and the small bones in the middle ear, resulting in a reduction of sound that reaches the inner ear. Causes of conductive hearing loss may include earwax buildup, fluid in the middle ear, a middle ear infection, a hole in the eardrum, or problems with the tiny bones in the middle ear. This type of hearing loss can often be treated through medical intervention or surgery.
The middle ear is the middle of the three parts of the ear, located between the outer ear and inner ear. It contains three small bones called ossicles (the malleus, incus, and stapes) that transmit and amplify sound vibrations from the eardrum to the inner ear. The middle ear also contains the Eustachian tube, which helps regulate air pressure in the middle ear and protects against infection by allowing fluid to drain from the middle ear into the back of the throat.
Otoscopy is a medical examination procedure used to evaluate the external auditory canal and tympanic membrane (eardrum). It involves the use of an otoscope, a tool that consists of a lighted speculum attached to a handle. The speculum is inserted into the ear canal, allowing the healthcare provider to visualize and inspect the eardrum for any abnormalities such as perforations, inflammation, fluid accumulation, or foreign bodies. Otoscopy can help diagnose various conditions including ear infections, middle ear disorders, and hearing loss.
Pure-tone audiometry is a hearing test that measures a person's ability to hear different sounds, pitches, or frequencies. During the test, pure tones are presented to the patient through headphones or ear inserts, and the patient is asked to indicate each time they hear the sound by raising their hand, pressing a button, or responding verbally.
The softest sound that the person can hear at each frequency is recorded as the hearing threshold, and a graph called an audiogram is created to show the results. The audiogram provides information about the type and degree of hearing loss in each ear. Pure-tone audiometry is a standard hearing test used to diagnose and monitor hearing disorders.
Mastoiditis is a medical condition characterized by an infection and inflammation of the mastoid process, which is the bony prominence located behind the ear. The mastoid process contains air cells that are connected to the middle ear, and an infection in the middle ear (otitis media) can spread to the mastoid process, resulting in mastoiditis.
The symptoms of mastoiditis may include:
* Pain and tenderness behind the ear
* Swelling or redness of the skin behind the ear
* Ear drainage or discharge
* Fever and headache
* Hearing loss or difficulty hearing
Mastoiditis is a serious condition that requires prompt medical attention. Treatment typically involves antibiotics to eliminate the infection, as well as possible surgical intervention if the infection does not respond to medication or if it has caused significant damage to the mastoid process. If left untreated, mastoiditis can lead to complications such as meningitis, brain abscess, or even death.
Menière disease is an inner ear disorder that is characterized by episodes of vertigo (a spinning sensation), tinnitus (ringing or buzzing in the ear), hearing loss, and aural fullness (a feeling of pressure or blockage in the ear). It is caused by an abnormal accumulation of endolymphatic fluid in the inner ear, which can lead to damage of the vestibular system and cochlea. The exact cause of this fluid buildup is not known, but it may be related to genetics, allergies, or autoimmune disorders. Menière disease is typically a chronic condition, with symptoms that can vary in frequency and severity over time. Treatment options include dietary modifications, diuretics, vestibular rehabilitation therapy, and, in some cases, surgery.
Operative surgical procedures refer to medical interventions that involve manual manipulation of tissues, structures, or organs in the body, typically performed in an operating room setting under sterile conditions. These procedures are carried out with the use of specialized instruments, such as scalpels, forceps, and scissors, and may require regional or general anesthesia to ensure patient comfort and safety.
Operative surgical procedures can range from relatively minor interventions, such as a biopsy or the removal of a small lesion, to more complex and extensive surgeries, such as open heart surgery or total joint replacement. The specific goals of operative surgical procedures may include the diagnosis and treatment of medical conditions, the repair or reconstruction of damaged tissues or organs, or the prevention of further disease progression.
Regardless of the type or complexity of the procedure, all operative surgical procedures require careful planning, execution, and postoperative management to ensure the best possible outcomes for patients.
The inner ear is the innermost part of the ear that contains the sensory organs for hearing and balance. It consists of a complex system of fluid-filled tubes and sacs called the vestibular system, which is responsible for maintaining balance and spatial orientation, and the cochlea, a spiral-shaped organ that converts sound vibrations into electrical signals that are sent to the brain.
The inner ear is located deep within the temporal bone of the skull and is protected by a bony labyrinth. The vestibular system includes the semicircular canals, which detect rotational movements of the head, and the otolith organs (the saccule and utricle), which detect linear acceleration and gravity.
Damage to the inner ear can result in hearing loss, tinnitus (ringing in the ears), vertigo (a spinning sensation), and balance problems.
Otitis media is an inflammation or infection of the middle ear. It can occur as a result of a cold, respiratory infection, or allergy that causes fluid buildup behind the eardrum. The buildup of fluid can lead to infection and irritation of the middle ear, causing symptoms such as ear pain, hearing loss, and difficulty balancing. There are two types of otitis media: acute otitis media (AOM), which is a short-term infection that can cause fever and severe ear pain, and otitis media with effusion (OME), which is fluid buildup in the middle ear without symptoms of infection. In some cases, otitis media may require medical treatment, including antibiotics or the placement of ear tubes to drain the fluid and relieve pressure on the eardrum.
Hearing loss is a partial or total inability to hear sounds in one or both ears. It can occur due to damage to the structures of the ear, including the outer ear, middle ear, inner ear, or nerve pathways that transmit sound to the brain. The degree of hearing loss can vary from mild (difficulty hearing soft sounds) to severe (inability to hear even loud sounds). Hearing loss can be temporary or permanent and may be caused by factors such as exposure to loud noises, genetics, aging, infections, trauma, or certain medical conditions. It is important to note that hearing loss can have significant impacts on a person's communication abilities, social interactions, and overall quality of life.
Sensorineural hearing loss (SNHL) is a type of hearing impairment that occurs due to damage to the inner ear (cochlea) or to the nerve pathways from the inner ear to the brain. It can be caused by various factors such as aging, exposure to loud noises, genetics, certain medical conditions (like diabetes and heart disease), and ototoxic medications.
SNHL affects the ability of the hair cells in the cochlea to convert sound waves into electrical signals that are sent to the brain via the auditory nerve. As a result, sounds may be perceived as muffled, faint, or distorted, making it difficult to understand speech, especially in noisy environments.
SNHL is typically permanent and cannot be corrected with medication or surgery, but hearing aids or cochlear implants can help improve communication and quality of life for those affected.
Howard P. House