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J B Nadol

Publications and source records attributed to J B Nadol.

At least 37 records · Page 2Linked to original sources
PubMed1999

Does otosclerosis occur only in the temporal bone?

HYPOTHESIS: Otosclerosis does not occur outside the temporal bone. BACKGROUND: The widely accepted assumption that otosclerosis is confined to the temporal bone has never been tested. It is important to investigate this issue, particularly because of evidence that otosclerosis may be a systemic (genetic) disease that could affect other bones. METHODS: Biopsies from 9 to 11 skeletal sites were obtained from 2 patients with clinical otosclerosis. Two hundred forty-one nontemporal bone sections were examined by light microscopy. RESULTS: No nontemporal skeletal bone section showed histologic evidence of otosclerosis. The data indicate, with 95% confidence, that the true prevalence of otosclerosis in the extratemporal skeleton of the 2 patients examined was < 3%. CONCLUSIONS: These findings suggest that otosclerosis is unlikely to occur outside the temporal bone. Factors unique to the otic capsule that may predispose it to otosclerosis are lack of bone remodeling and the presence of globuli interossei.

Adult↗
PubMed1999

Delayed intracranial abscess after acoustic neuroma surgery: a report of two cases.

OBJECTIVE: The use of antibiotics before and after surgery has made infectious complications of neurotologic surgery rare. The neurosurgical literature cites a rate of postoperative meningitis between 1% and 2% for "clean" cases and 1.5% to 2.5% for "clean contaminated" cases, such as cerebrospinal fluid contact with the middle ear or mastoid. Reports of infections after neurotologic procedures are rare in the otologic literature. In this report, two patients with brain abscess occurring in a delayed fashion after surgery are described. STUDY DESIGN: The study design was a retrospective chart review and case report. SETTING: The study was conducted at a tertiary referral center. RESULTS: Patient 1 underwent a suboccipital craniotomy for removal of an acoustic neuroma and had an uneventful postoperative recovery. Three months after surgery, he reported mild unsteadiness. Examination revealed mild ataxia, which led to repeat magnetic resonance imaging (MRI) and a diagnosis of cerebellar abscess. Patient 2 underwent translabyrinthine removal of an acoustic neuroma complicated by postoperative Pseudomonas aeruginosa meningitis, which responded promptly to intravenous antibiotics. Fifteen months after surgery, he visited a neurologist after having a seizure and was treated with anticonvulsants. After a second episode of seizure, imaging studies showed a temporal lobe abscess. CONCLUSIONS: The signs of intracranial abscess may be subtle and can occur weeks or months after surgery, requiring vigilance and a high index of suspicion for diagnosis. A change in postoperative symptoms after acoustic neuroma surgery should signal further investigation using MRI with gadolinium.

Adult↗
PubMed1999

Osteomyelitis, lateral sinus thrombosis, and temporal lobe infarction caused by infection of a percutaneous cochlear implant.

OBJECTIVE: Cochlear implantation has become a routine operation in the last 10 years. The most common soft tissue complications with transcutaneous cochlear implants include infection or necrosis of the flap and extrusion of the implant and device failure. The most common complication reported with percutaneous devices include minor skin irritations at the pedestal site, retraction of skin from the pedestal site, and loosening of screws that retain the pedestal. We describe one case of lateral sinus thrombosis and secondary temporal lobe infarction caused by infection of a screw anchoring the percutaneous pedestal of an Ineraid implant. STUDY DESIGN: Case report. SETTING: Tertiary referral center. CONCLUSIONS: Intracranial complications of a percutaneous bone-anchored pedestal may occur with little prodrome. Computed tomography (CT) scan of the pedestal and bone anchoring screws may be indicated if local evidence of infection persists.

Anti-Bacterial Agents↗
PubMed1998

Dense innervation of Deiters' and Hensen's cells persists after chronic deefferentation of guinea pig cochleas.

Innervation of Deiters' and Hensen's cells has been described in the organ of Corti of several mammalian species and has been suggested to arise from the olivocochlear (OC) efferent system (Wright and Preston [1976] Acta Otolaryngol. 82:41-47). In the present study, antineurofilament immunostaining was used to reveal these outer supporting cell fibers (OSCFs) in the normal guinea pig. In control ears, OSCFs were absent in the basal half of the cochlea but increased in number steadily toward the apex, peaking at values of over 1,200 fibers/mm. These values indicate a far more profuse innervation of supporting cells than has been described previously, suggesting that most OSCFs were not stained in previous immunohistochemical studies. Chronic cochlear deefferentation was used to test whether OSCFs are part of the OC system. The OC bundle was transected unilaterally, and the animals were allowed to survive for 4-8 weeks. Completeness of deefferentation was assessed by using acetylcholinesterase staining of the brainstem and measurement of the density of OC fascicles in the cochlea. By using these metrics, unilateral deefferentation was nearly complete in three animals. In successfully deefferented cases, the OSCF innervation density was not statistically different from control values. We conclude that the vast majority of OSCFs are not of OC origin. We speculate that they may be branches of type II afferent fibers to outer hair cells and that a smaller population of OSCFs with different morphology and immunoreactivity may arise from the OC system.

Acetylcholinesterase↗
PubMed1998

Mutations in a novel cochlear gene cause DFNA9, a human nonsyndromic deafness with vestibular dysfunction.

DFNA9 is an autosomal dominant, nonsyndromic, progressive sensorineural hearing loss with vestibular pathology. Here we report three missense mutations in human COCH (previously described as Coch5b2), a novel cochlear gene, in three unrelated kindreds with DFNA9. All three residues mutated in DFNA9 are conserved in mouse and chicken Coch, and are found in a region containing four conserved cysteines with homology to a domain in factor C, a lipopolysaccharide-binding coagulation factor in Limulus polyphemus. COCH message, found at high levels in human cochlear and vestibular organs, occurs in the chicken inner ear in the regions of the auditory and vestibular nerve fibres, the neural and abneural limbs adjacent to the cochlear sensory epithelium and the stroma of the crista ampullaris of the vestibular labyrinth. These areas correspond to human inner ear structures which show histopathological findings of acidophilic ground substance in DFNA9 patients.

Amino Acid Sequence↗
PubMed1998

Correlation of acoustic threshold measures and spiral ganglion cell survival in severe to profound sensorineural hearing loss: implications for cochlear implantation.

In a temporal bone study of 26 ears from 13 patients who, in life, had severe sensorineural hearing loss, the segmental and total spiral ganglion cell (SGC) counts were correlated with hearing thresholds and with the difference between hearing thresholds in the two ears, the age at death, the duration of deafness, and the duration of hearing loss. A statistically significant correlation was found between the interaural differences in total SGC counts and the interaural difference in pure tone averages for 3, 4, and 5 frequencies. The total SGC count was higher in the ear with the better residual hearing in 11 of 12 cases. Approximately 41% of the variability in interaural difference in pure tone average was explained by the difference in SGC counts. The findings would suggest that in a given individual, selection of the ear with better residual hearing for cochlear implantation is likely to result in accessing a higher number of residual SGCs. This, in turn, may result in better speech recognition with the implant.

Adolescent↗
PubMed1998

Single-channel to multichannel conversions in adult cochlear implant subjects.

OBJECTIVE: This study aimed to compare open-set speech perception of single-channel with multichannel cochlear implants in the same ear of postlingually deafened adults. STUDY DESIGN: The study design was a retrospective case and literature review. SETTING: The study was conducted at a tertiary referral center with an associated veterans administration hospital. PATIENTS: Postlingually deafened adults with at least 6 months of experience with a single-channel cochlear implant were studied. INTERVENTION: Replacement of a single-channel with a multichannel cochlear implant in the same ear was performed. MAIN OUTCOME MEASURES: Open-set word and sentence perception scores at least 6 months after single-channel implantation and multichannel reimplantation were measured. RESULTS: Six of six patients had substantial improvement in open-set speech recognition after reimplantation of the same ear. CONCLUSIONS: Removal of a functioning single-channel implant and replacement with a multichannel device are appropriate in postlingually deafened adults who desire better speech recognition.

Adult↗
PubMed1997

Patterns of neural degeneration in the human cochlea and auditory nerve: implications for cochlear implantation.

Although the identity of all the variables that may influence speech recognition after cochlear implantation is unknown, the degree of preservation of spiral ganglion cells is generally considered to be of primary importance. A series of experiments in our laboratories, directed at quantification of surviving spiral ganglion cells in the profoundly deaf, evaluation of the predictive value of a variety of clinical parameters, and the evaluation of the consequences of implantation in the inner ear, is summarized. Histologic study of the inner ears of patients who were deafened during life demonstrated that the cause of deafness accounted for 57% of the variability of spiral ganglion cell counts. Spiral ganglion cell counts were highest in individuals deafened by aminoglycoside toxicity or sudden idiopathic deafness and lowest in those deafened by postnatal viral labyrinthitis, congenital or genetic deafness, or bacterial meningitis. Study of the determinants of degeneration of the spiral ganglion revealed that degeneration is most severe in the basal compared with the apical turn and more severe when both inner and outer hair cells are absent. Unlike the findings in some experimental animal studies, no survival advantage of type II ganglion cells could be identified. There was a strong negative correlation between the degree of bony occlusion of the cochlea and the normality of the spiral ganglion cell count. However, even in specimens in which there was severe bony occlusion, significant numbers of spiral ganglion cells survived. A strong positive correlation between the diameter of the cochlear, vestibular, and eighth cranial nerves with the total spiral ganglion cell count (p < 0.001) was found. This would suggest that modern imaging techniques may be used to predict residual spiral ganglion cell population in cochlear implant candidates. Trauma from implantation of the electrode array was studied in both cadaveric human temporal bone models and temporal bones from individuals who received implants during life. A characteristic pattern of damage to the lateral cochlear wall and basilar membrane was identified in the upper basal turn. New bone formation and perielectrode fibrosis was common after cochlear implantation. Despite this significant trauma and reaction, there is no firm evidence that further degeneration of the spiral ganglion can be predicted as a consequence.

Aged↗
PubMed1997

Morphologic evidence for innervation of Deiters' and Hensen's cells in the guinea pig.

The presence of nerve fibers and terminals among Deiters' and Hensen's cells of the organ of Corti of the adult guinea pig is demonstrated using immunostaining for synaptophysin and neurofilaments, acetylcholinesterase histochemistry, and transmission electron microscopy. These nerve terminals appeared to form chemical synapses with Deiters' and Hensen's cells. Nerve fibers and synapses were more common in the apical as compared to the basal cochlea. The terminals were often present on basal appendages of Hensen's cells, which were rich in mitochondria and often contained a Golgi apparatus and dense core vesicles. Electron microscopy and immunostaining for neurofilaments showed that most Hensen's cells in the apical cochlea received innervation. Few of the nerve fibers and terminals were positive for acetylcholinesterase, which suggests that they were not collaterals of cholinergic olivocochlear fibers. The density of these fibers, as shown by immunohistochemistry for neurofilaments, was far greater than previous reports of GABA-ergic fibers, which suggests that they were not GABA-ergic olivocochlear fibers. The role of such fibers and synapses with supporting cells of the outer hair cell area is unknown. Determination of the origins and functions of these fibers will provide new insights into cochlear structure and function.

Acetylcholinesterase↗
PubMed1997

Efficacy of tympanomastoid surgery for control of infection in active chronic otitis media.

The efficacy of surgery in controlling infection in 272 tympanomastoidectomy procedures for chronic otitis media (COM) was assessed by means of a four-point rating scale that incorporated both symptoms and signs, such as the presence or absence of otorrhea and granulation tissue. Of the 272 procedures, 170 were performed for COM with cholesteatoma and 102 were for active COM with granulation tissue but no cholesteatoma. Forty-seven percent were primary procedures, and 53% were revisions. Minimum follow-up was 12 months for all cases, with a mean of 30 months. Adequate control of infection occurred in 248 (91%) of the 272 cases. Of the 24 cases (9%) that developed persistent infection, 10 were controlled with a combination of oral and topical antibiotics and/or delayed skin grafting in the office. Thus overall satisfactory control of infection was achieved in 258 of 272 cases (95%). The outcome was influenced by the diagnostic category of COM: COM with cholesteatoma did significantly better than COM with granulation tissue (P = 0.02). The outcome was not influenced by the following variables: primary versus revision surgery, canal wall-up versus canal wall-down surgery, and extent of disease. The results suggest that active COM with granulation tissue may be more difficult to control than COM with cholesteatoma.

Administration, Oral↗
PubMed1997

Revision stapedectomy: intraoperative findings, results, and review of the literature.

Seventy-four revision stapedectomies performed consecutively over 10 years (1986 to 1995) were reviewed retrospectively. The most common intraoperative findings were incus erosion, prosthesis displacement, and oval window closure. Incus erosion was more frequently associated with multiple revisions. The postoperative results were reported using the conventional method (postoperative air minus preoperative bone) as well as the guidelines recently published by the American Academy of Otolaryngology--Head and Neck Surgery (postoperative air minus postoperative bone), with success rates of postoperative air-bone gap closure to within 10 dB after revision surgery of 51.6% and 45.6%, respectively. Patients with persistent conductive hearing loss (large residual air-bone gaps) after primary stapedectomy had poorer postrevision hearing results. Sensorineural hearing loss (defined as a drop in bone pure-tone average of more than 10 dB) occurred in four cases (5.4%). The number of revision surgeries, variations in operative techniques using laser or drill, and the ossicle to which the prosthesis was attached did not statistically affect the postoperative air-bone gaps. These results were compared with previously published data.

Adult↗
PubMed1997

Nucleus 22 cochlear implantation results in postmeningitic deafness.

Cochlear implant surgery was performed on 13 patients with postmeningitic deafness (seven adults, six children). Two adults and two children (30.8%) had severe labyrinthitis ossificans requiring radical "drill-out." Five of 13 (38.5%) had some bone growth requiring partial drill-out, and four of 13 (30.8%) had normal insertion with no drill-out. Hearing results for patients with no bone growth were similar to nonmeningitic patients; three of four (75%) had open-set speech recognition. Performance of patients with total drill-out was poor; "auditory only" performance was limited to detection and pattern perception of speech, and no patients had open-set speech recognition. Results for patients with partial drill-out were similar to results in patients with no bone growth. Labyrinthitis ossificans not only presents surgical challenges to cochlear implantation but may also adversely affect hearing outcome.

Adolescent↗
PubMed1996

Morphologic evidence for three cell types in the human spiral ganglion.

Although two types of spiral ganglion cells (large type I and smaller type II) have classically been described by anatomic studies in both animal and human spiral ganglion, there is physiologic and morphologic evidence for subtypes of the large type I ganglion cell. In addition, in the animal and human, a variety of morphologic differences based on cytoplasmic content, myelinization, immunostaining and morphometric analysis have suggested more than one variety of type I ganglion cell. Light and electron microscopic serial sections of the spiral ganglion in two human specimens in the basal, middle and upper middle turns were pooled for morphometric analysis of the cell area, nuclear area and axon diameter. Analysis of variance, bivariate scatter plots and multivariate cluster analysis provided evidence for 3 types of ganglion cells in the human spiral ganglion: large, intermediate and small, varying from each other significantly on the basis of cell area. It was suggested, based on the morphologic findings and prevalence of the cell types, that the large and intermediate cells were subtypes of the classic type I spiral ganglion cell, whereas the small ganglion cell was consistent with the classically described type II ganglion cell.

Adult↗
PubMed1996

Techniques for human temporal bone removal: information for the scientific community.

Human temporal bones provide an irreplaceable resource for study of the pathology and pathophysiology of disorders of hearing, balance, taste, and facial nerve function. Additional specimens are needed to study disorders for which there are few human specimens; to increase the number of specimens for a given disorder to understand the natural variability and expression of the disease entity; to evaluate the accuracy of otologic diagnoses and the efficacy of otologic treatment modalities; to apply newly available scientific methods, including immunohistochemistry and molecular biologic or molecular genetic techniques; and to teach the anatomy of the human ear and modern otologic surgical techniques. This article provides information for the scientific community concerning techniques for temporal bone and auditory brain stem removal, including intracranial and extracranial approaches and methods to minimize postmortem autolysis and cosmetic defects. Close collaboration between physicians and funeral directors will maximize the yield and utility of these valuable specimens for scientific inquiry and training.

Brain Stem↗