Biomedical subjects

Ophir Handzel

Publications and source records attributed to Ophir Handzel.

6 recordsLinked to original sources

PubMed2006

Histopathology of the peripheral vestibular system after cochlear implantation in the human.

OBJECTIVES: The objective of this study was to describe the histology of the peripheral vestibular system in temporal bones from patients who in life had undergone cochlear implantation and to correlate the findings with previous reports of vestibular dysfunction after cochlear implantation. This is the first quantitative report of the impact of implantation on the vestibular neuronal end organ. METHODSThere were 19 temporal bones available for histologic study. Of these, 17 were suitable for the description of the morphology of the membranous labyrinth, 8 for counting Scarpa's ganglion cells, and 6 for measuring the densities of vestibular hair cells. The bones were fixed, cut, and stained according to previously published methods. Preferably, the implanted electrode was left in situ. Vestibular hair cells were counted with Nomarski's optics. RESULTS: Differences in Scarpa's ganglion cell counts and hair cell densities between the implanted and nonimplanted sides were not statistically significant. In 59% of the implanted bones, the cochlea was hydropic, and in the majority of these bones the saccule was collapsed. CONCLUSION: Cochlear implantation does not cause deafferentation of the peripheral vestibular system. Cochlear hydrops accompanied by saccular collapse is common and may cause attacks of vertigo of delayed onset, similar to Ménière's syndrome as previously reported in several clinical series. Hydrops could be caused by obstruction of endolymphatic flow in the ductus reuniens or in the hook portion of the cochlea or by damage to the lateral cochlear wall caused by implantation.

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PubMed2005

Is word recognition correlated with the number of surviving spiral ganglion cells and electrode insertion depth in human subjects with cochlear implants?

OBJECTIVES/HYPOTHESIS: Speech perception scores using cochlear implants have ranged widely in all published series. The underlying determinants of success in word recognition are incompletely defined. Although it has been assumed that residual spiral ganglion cell population in the deaf ear may play a critical role, published data from temporal bone specimens from patients have not supported this hypothesis. The depth of insertion of a multichannel cochlear implant has also been suggested as a clinical variable that may be correlated with word recognition. In the current study these correlations were evaluated in 15 human subjects. STUDY DESIGN: Retrospective review of temporal bone histopathology. METHODS: Temporal bones were fixed and prepared for histological study by standard techniques. Specimens were then serially sectioned and reconstructed by two-dimensional methods. The spiral ganglion cells were counted, and the depth of insertion of the cochlear implant as measured from the round window was determined. Correlation analyses were then performed between the NU6 word scores and spiral ganglion cell counts and the depth of insertion. RESULTS: The segmental and total spiral ganglion cell counts were not significantly correlated (P > .50) with NU6 word scores for the 15 subjects. Statistically significant correlations were not achieved by separate analysis of implant types. Similarly, no significant correlation between the depth of insertion of the electrode array and postoperative NU6 word score was identified for the group. CONCLUSION: Although it is unlikely that the number of residual spiral ganglion cell counts is irrelevant to the determination of word recognition following cochlear implantation, there are, clearly, other clinical variables not yet identified that play an important role in determining success with cochlear implantation.

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PubMed2005

Postauricular needle aspiration of subperiosteal abscess in acute mastoiditis.

To test the hypothesis that subperiosteal abscess, a complication of acute mastoiditis, can be treated equally well by needle aspiration as by cortical mastoidectomy, we performed a retrospective analysis of 78 pediatric patients hospitalized between 1995 and 2003 and performed an analysis of published data on types and outcomes of treatment approaches for acute mastoiditis. Postauricular pus aspiration resolved the subperiosteal abscess in 14 of 17 patients. The length of the hospital stay of patients who underwent aspiration was shorter than that of patients who underwent cortical mastoidectomy. We conclude that postauricular pus aspiration, a simple and minimally invasive procedure, is an effective treatment modality for subperiosteal abscess. Mastoidectomy should be reserved for nonresponsive cases or those with more serious complications. Broad-spectrum antibiotics, myringotomy with daily toilet of the ear, and postauricular aspiration, when required, minimize the indications for surgery and reduce the hospital stay.

Abscess↗

PubMed2005

Effect of cochlear implantation on residual spiral ganglion cell count as determined by comparison with the contralateral nonimplanted inner ear in humans.

It is generally assumed that at least a minimal number of spiral ganglion cells is essential for successful speech perception with a cochlear implant. Although the insertion of a multichannel cochlear implant frequently results in loss of residual hearing in the implanted ear, this outcome does not imply that significant damage to residual populations of spiral ganglion cells has occurred. The purpose of the current study was to compare spiral ganglion cell counts in implanted and nonimplanted cochleas in 11 patients for whom both temporal bones were available and in whom a multichannel cochlear implant had been placed unilaterally. The temporal bones were processed for light microscopy by standard techniques. The cochleas were reconstructed by 2-dimensional methods. Spiral ganglion cell counts of the implanted and nonimplanted sides were compared by a paired t-test (2-tailed). The mean spiral ganglion cell counts for implanted and nonimplanted ears were not statistically different in the most basal three segments of the cochlea. However, the mean spiral ganglion cell count in segment 4 (apical segment) and the mean total spiral ganglion cell count were lower in the implanted cochleas than in the nonimplanted cochleas (p < .01). The results of this study suggest a modest decrease in the total spiral ganglion cell count in the implanted ears as compared to the nonimplanted ears, principally in the apical segment. Possible interpretations of this finding are discussed.

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PubMed2003

Necrotizing (malignant) external otitis.

Necrotizing (malignant) external otitis, an infection involving the temporal and adjacent bones, is a relatively rare complication of external otitis. It occurs primarily in immunocompromised persons, especially older persons with diabetes mellitus, and is often initiated by self-inflicted or iatrogenic trauma to the external auditory canal. The most frequent pathogen is Pseudomonas aeruginosa. Patients with necrotizing external otitis complain of severe otalgia that worsens at night, and otorrhea. Clinical findings include granulation tissue in the external auditory canal, especially at the bone-cartilage junction. Facial and other cranial nerve palsies indicate a poor prognosis; intracranial complications are the most frequent cause of death. Diagnosis requires culture of ear secretions and pathologic examination of granulation tissue from the infection site. Imaging studies may include computed tomographic scanning, technetium Tc 99m medronate bone scanning, and gallium citrate Ga 67 scintigraphy. Treatment includes correction of immunosuppression (when possible), local treatment of the auditory canal, long-term systemic antibiotic therapy and, in selected patients, surgery. Family physicians and others who provide medical care for immunocompromised patients should be alert to the possibility of necrotizing external otitis in patients who complain of otalgia, particularly if they have diabetes mellitus and external otitis that has been refractory to standard therapy. Susceptible patients should be educated to avoid manipulation of the ear canal (i.e., they should not use cotton swabs to clean their ears) and to minimize exposure of the ear canal to water with a high chloride concentration. Appropriate patients should be referred to an otolaryngologist.

Anti-Bacterial Agents↗

PubMed2003

Liposomal amphotericin B treatment for rhinocerebral mucormycosis: how much is enough?

Rhinocerebral Mucormycosis is a potentially life-threatening disease, which affects mainly immunocompromised patients. Treatment options include reversing immunosuppression, surgery and systemic and local administration of anti-fungal medication. Amphotericin B is the primary agent employed, but its use is often limited by frequent side effects. Complexing Amphotericin B with lipid structures avoids most of the negative side effects, most importantly the dose-limiting nephrotoxicity. No consensus has been reached regarding the appropriate duration, rate of administration or total dose of treatment. We present a case of a patient suffering from Rhinocerebral Mucormycosis treated by extensive surgery and Liposomal Amphotericin B. He was treated for 29 days at a rate of 3 mg/kg/d and a total dose of 5.6 gram. The dose of Liposomal Aphotericin B used in previously published articles ranged from 1.5 mg/kg/d to 5 mg/kg/d. The response to treatment may be evaluated by physical examination, microbiological cultures, radiological and pathological studies. Taking into account the considerable cost of liposomal Amphotericin B and other lipid complexed formulations, it is imperative to find out what is the appropriate treatment regime for Rhinocerebral and other mucormycosis infections.

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