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Biomedical subjects

M Bance

Publications and source records attributed to M Bance.

15 recordsLinked to original sources
PubMed2004

Vibration characteristics and function of atelectatic segments in the tympanic membrane in fresh human cadaveric temporal bones.

Dimeric segments are commonly encountered in otological practice. They may be associated with a mild conductive hearing loss and often coexist with other tympanic membrane and middle ear abnormalities. Some otologists have advocated surgical management but the consequences of dimeric segment stiffening, shielding or excision and grafting on acoustic transfer to the stapes footplate has been poorly explored. In this study, laser Doppler vibrometry was used to measure vibrations at the tympanic membrane and the stapes footplate in the fresh cadaveric human temporal bone. The dimeric segment vibrates more than the adjacent, thicker normal tympanic membrane. Shielding or excision and grafting of the dimeric segment with thicker and stiffer materials has little effect on displacement at the stapes footplate.

Bone Conduction↗
PubMed2001

Effects of varying unilateral conductive hearing losses on speech-in-noise discrimination: an experimental study with implications for surgical correction.

HYPOTHESIS: Unilateral conductive hearing loss (HL) causes measurable disability in realistic hearing environments. The benefits of improving this loss depend both on the absolute level of final hearing and on hearing asymmetry. BACKGROUND: Surgical success is often measured by the degree of change in the air-bone gap or in the air thresholds. The Glasgow Benefit Plot and the Belfast Rule of Thumb suggest that a given hearing gain will be of greater benefit if the postoperative thresholds in the worse ear are a <30-dB HL or within 15 dB of the contralateral ear. This assertion has important surgical implications, but few audiometric data supporting it currently exist. METHODS: Speech-in-noise sound-field scores were measured in 16 normal volunteers at three presentation levels at two signal-to-noise ratios (SNRs). Two levels of unilateral conductive HL were simulated with earplugs, averaging 25-and 43-dB HL, respectively, and the effect on speech-in-noise scores was measured and analyzed. RESULTS: Unilateral conductive HL is a disadvantage at lower sound intensities and low SNRs, but it can be compensated for by increasing volume or SNR. The benefits of improving unilateral conductive HL are greater if the final asymmetry is <25 dB and the final hearing threshold is <25 dB. CONCLUSIONS: Unilateral conductive HL is a significant disadvantage at low SNRs or presentation volumes. The benefits of surgery to improve HL depend not only on the degree of hearing improvement but also on the final hearing threshold in both ears.

Adult↗
PubMed2001

Severe audiovestibular loss following ear syringing for wax removal.

Syringing of the ear is one of the commonest procedures performed for cleaning cerumen from the external auditory canal. Common complications following syringing are pain, external auditory canal trauma and otitis externa. Hearing and vestibular loss are often mentioned as a complication in descriptions of this technique, but we have not been able to find a reported case of such an occurrence. We report one such a case.

Aged↗
PubMed2001

Glioblastoma multiforme occurring in a patient treated with gamma knife surgery. Case report and review of the literature.

Stereotactic radiosurgery is being increasingly advocated as the primary modality for treatment of vestibular schwannomas (VS). This modality has been shown to arrest tumor growth, with few associated short-term morbidities, and with possibly better hearing and facial nerve preservation rates than microsurgery. Radiation-induced oncogenesis has long been recognized, although stereotactic radiosurgery de novo induction of a secondary tumor has never been clearly described. The authors report on a patient with a VS who did not have neurofibromatosis Type 2 and who underwent gamma knife surgery (GKS). This patient required microsurgical removal of the VS within 8 months because of development of a tumor cyst with associated brainstem compression and progressive hydrocephalus. The operation resulted in clinical stabilization and freedom from tumor recurrence. Seven and a half years after undergoing GKS, the patient presented with symptoms of raised intracranial pressure. Magnetic resonance imaging demonstrated a new ring-enhancing lesion in the inferior temporal lobe adjacent to the area of radiosurgery, which on craniotomy was confirmed to be a glioblastoma multiforme (GBM). Despite additional conventional external-beam radiation to the temporal lobe, the GBM has progressed. Whereas this first reported case of a GBM within the scatter field of GKS does not conclusively prove a direct causal link, it does fulfill all of Cahan's criteria for radiation-induced neoplasia, and demands increased vigilance for the potential long-term complications of stereotactic radiosurgery, and reporting of any similar cases.

Brain Neoplasms↗
PubMed1999

Carbamazepine-induced sensorineural hearing loss.

Carbamazepine is a commonly prescribed anticonvulsant medication that affects various levels of the nervous system. We report a case of temporary sensorineural hearing loss in a patient after overdosing with 36 g of carbamazepine. Six days after the overdose, the patient complained of bilateral hearing loss and tinnitus. Audiograms revealed a 30- to 40-dB sensorineural hearing loss bilaterally. Another audiogram 2 weeks later showed a complete recovery in both ears accompanied by a clinical resolution in audiovestibular symptoms. Carbamazepine is used to treat partial and generalized seizures, trigeminal neuralgia, and bipolar illness. Adverse effects are not common but most frequently include dizziness, drowziness, nausea, and skin rashes; rare complications are agranulocytosis, bradycardia, and heart block. Documented hearing loss as a side effect of carbamazepine has not been reported, to our knowledge.

Adult↗
PubMed1999

Management of neurofibromatosis type 2.

Neurofibromatosis type 2 (NF2), an as-yet incurable disease that predisposes patients to multiple intracranial and spinal tumors, requires a team approach to treatment, because of its multisystem nature. Included on the team should be neuro-otologists, neurosurgeons, ophthalmologists, geneticists, audiologists, speech therapists and other rehabilitative personnel, including counselors, psychologists and, occasionally, psychiatrists. The challenge is to arrive at a treatment strategy that preserves useful hearing and quality of life without increasing the risk of complications to the facial nerve or compromising neurologic status. Choosing the best treatment approach involves considering a complex set of competing factors that affect various aspects of the patient's outcome.

Facial Paralysis↗
PubMed1999

The risk of hearing loss in nongrowing, conservatively managed acoustic neuromas.

OBJECTIVE: To determine the risk of loss of useful hearing in the absence of tumor growth among patients undergoing conventional management of acoustic neuroma. SETTING: Tertiary referral center. STUDY DESIGN: Retrospective case review. PATIENTS: Ten patients (12 ears) were identified having a period of no tumor growth of at least 6 months (19.0+/-12.8 months), and for whom at least two audiograms were available in this period. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Loss of useful hearing defined using 70% speech discrimination score (SDS) and 30 dB pure tone average (PTA) (70/30), or 50% SD and 50 dB PTA (50/50) criteria. RESULTS: Three of seven (43%) ears with useful hearing using the 70/30 rule and two of eight ears (25%) using the 50/50 rule lost this useful hearing. CONCLUSIONS: There is a significant risk of useful hearing loss with conservative management of nongrowing acoustic neuromas.

Adult↗
PubMed1998

Bilateral sudden sensorineural hearing loss following non-otologic surgery.

Hearing loss as a complication of non-otological surgery is rare. The majority of described cases have followed cardiac bypass surgery. To date there have been only 25 reported cases of non-otological surgery associated hearing loss (NOSAHL) which have not involved cardiopulmonary bypass. Only two cases of bilateral NOSAHL have been previously described, and neither resulted in permanent severe bilateral hearing deficit. We describe a case of permanent bilateral severe hearing loss following metatarsal pinning in a patient with pre-existing non-operated otosclerosis.

Audiometry↗
PubMed1997

Cochlear implantation in otosclerosis: a unique positioning and programming problem.

A case is reported in which a Nucleus 22 channel cochlear implant was inserted into the basal turn of the cochlea of a patient with advanced otosclerosis. It then passed out of the anterior end of the basal turn into an otospongiotic cavity related to the cochlea. Seven electrodes were located in the basal turn and it was possible to map them sufficiently well for the patient to derive considerable benefit from the implant. The problem of implant induced facial nerve stimulation in otospongiosis is also discussed.

Cochlear Implants↗
PubMed1996

Explantation of a nucleus multichannel cochlear implant and re-implantation into the contralateral ear. A case report of a new strategy.

We present a unique case in which a multichannel cochlear implant device was explanted and the same device was re-implanted into the contralateral ear. A patient with bilateral total deafness secondary to head injury received an implant in his left ear but developed severe facial nerve stimulation. Because this stimulation could not be eliminated effectively with change of programming, it was decided to implant the contralateral ear. Since the device itself was functioning well, it was explanted from the left ear and re-implanted successfully into the right ear. Facial nerve stimulation was minimal in this ear and the patient demonstrated very good speech discrimination. To our knowledge, this is the first description of this strategy.

Aged↗
PubMed1995

Comparison of laser Doppler flowmeter and radioactive microspheres in measuring blood flow in pig skin flaps.

Laser Doppler flowmetry is a noninvasive technique commonly used to monitor skin perfusion after free-tissue transfer or replantation in reconstructive surgery. Several investigators have expressed concern about the reliability of the quantitative value provided by laser Doppler flowmeters (LDF) and the extent to which they reflect nutrient blood flow. This experiment was designed to compare quantitatively the skin blood flow in the pig measured by LDF and by 15-micron radioactive microspheres (RMs). It was observed that the skin blood flow rates measured by LDF and RMs in the normal skin and in acute random-pattern and arterialized skin flaps were highly correlated (r = 0.93, P < .01). However, the skin blood flow rates measured by LDF were consistently higher (P < or = .05) than the corresponding flow rates measured by RMs, and this discrepancy increased considerably at low skin blood flow rates (< 2 mL/min/100 g). We speculated that the LDF most likely measured both nutrient and arteriovenous shunt flow in the skin and that this arteriovenous shunt flow at least in part caused the discrepancy in skin blood flow rates measured by the LDF and RMs because the 15-micron RMs are known to measure nutrient blood flow only. The inherent variations and errors in LDF technique were also discussed.

Animals↗
PubMed1991

The changing direction of nystagmus in acute Menière's disease: pathophysiological implications.

The direction(s) and pathophysiologic basis of nystagmus during an acute attack of Menière's disease have been subject to much debate in the world literature. Clinical recordings from two patients whose nystagmus was captured near the very beginning of the acute vertiginous episode are presented. Previous clinical observations in Meniere's disease, experimental animal models concerned with initiation of peripheral nystagmus, and the phenomenon of recovery are discussed.

Acute Disease↗
PubMed1990

Speculation into the etiologic role of viruses in the development of Bell's palsy and disorders of inner ear dysfunction: a case history and review of the literature.

It has long been postulated that Bell's palsy and a number of inner ear disorders may have as their basis a common underlying viral etiology. The change from one recognizable inner ear disorder into another is not unusual in the same patient and has been recognized by neurotologists. The case history of a patient who initially presented with an idiopathic facial palsy that years later developed into a spectrum of vestibular dysfunction associated with the clinical stigmata of herpes zoster is discussed. Although difficult to prove, support for this continuum theory is reviewed, taking into account known viral involvement in other cranial nerves and various histopathologic findings from disorders involving the inner ear and facial nerve.

Adult↗