bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal Stimulus Duration for Intraoperative Facial Nerve Monitoring
Authors: Selesnick Samuel H. 
Published: November 2003

AbstractObjectives/Hypothesis: The charge delivered to the facial nerve during intraoperative facial nerve monitoring (IOFNM) is the product of the stimulation amplitude and the duration for which the pulse of charge is applied. In the literature, no standard for pulse duration exists, precluding meaningful comparison of IOFNM between studies. The optimal stimulus pulse duration can be derived from facial nerve strength duration curve analysis and calculation of chronaxy. Chronaxy is directly related to the time constant, τ, of the neuronal membrane, and is a function of neuronal membrane resistance and capacitance.Study Design: A prospective trial of facial nerve stimulation in both an animal and a human model.Methods: Five rabbits and 17 humans underwent intraoperative stimulation of healthy facial nerves. Pulse durations using pulses of 10, 20, 50, and 100 microseconds were employed, and the corresponding threshold stimulation amplitudes were recorded. From these data sets, strength duration curves were plotted and chronaxy values calculated.Results: Average chronaxy values of 18 microseconds in the rabbit and 32 microseconds in the human were found. Given IOFNM system accuracy limitations, the optimal pulse duration for facial nerve stimulation is 50 microseconds.Conclusion: Most commercially available intraoperative monitoring systems employ a pulse duration default setting of 100 microseconds. Doubling of the 50‐microsecond optimal pulse duration may result in a loss of sensitivity of predictive facial nerve data. Both the stimulation amplitude and the selected pulse duration should be reported by investigators so that meaningful comparison of the IOFNM data in the literature can be made.
Transcochlear Repair of Persistent Cerebrospinal Fluid Leaks
Authors: Grant Iain L. , Welling D. Bradley , Oehler Mary C. , Baujan Melissa A. 
Published: November 2003

AbstractObjective: The purpose of this study is to demonstrate the utility of a modified transcochlear obliteration of the petrous apex in repair of persistent cerebrospinal fluid (CSF) leaks. A review of temporal bone computed tomography (CT) scans and histological preparations for potential air cells leading to such leaks is also presented.Study Design: Retrospective case review in an academic tertiary referral center.Methods: Patients for inclusion in this study had previously undergone either a suboccipital or translabyrinthine removal of an intracranial tumor with subsequent transmastoid and middle ear obliteration of air cell tracts to stop a CSF leak. Ninety CT scans and 178 temporal bones were reviewed and assessed for peritubal and petrous apex pneumatization.Results: Four patients had initial obliteration of the orifice of the eustachian tube and middle ear that failed to prevent leakage of CSF. The leak was ultimately controlled by a transcochlear petrous apicectomy. From The Ohio State University temporal bone collection, 178 specimens were available for examination. Peritubal pneumatization was found in 42% of the bones examined. The CT scans showed unilateral petrous apex pneumatization in 30% of the specimens and bilateral pneumatization in 11%.Conclusions: Continuity of air cell tracts from the petrous apex surrounding the internal auditory canal to the medial eustachian tube can provide a path for CSF rhinorrhea that is difficult to stop by conventional means. A modified transcochlear approach successfully terminated persistent leaks in four such patients.
Hemangiopericytoma of the Head and Neck
Authors: Carew John F. , Singh Bhuvanesh , Kraus Dennis H. 
Published: November 2003

AbstractObjective/Hypothesis: Hemangiopericytomas are uncommon neoplasms of vascular origin that may arise in the head and neck. Their rare occurrence and variable malignant potential have limited attempts to characterize their clinical behavior. This study reviews the experience in treating hemangiopericytomas of the head and neck at a single institution.Study Design: Retrospective.Methods: The records of 12 patients with hemangiopericytomas of the head and neck presenting between 1979 and 1995 were reviewed. Site of origin included the neck (4), oral cavity (3), parotid (2), orbit (1), maxillary sinus (1) and mandible (1). Five patients had lesions characterized as high or intermediate grade histologically, and six had lesions characterized as low grade.Results: Nine patients were treated with curative intent; three presented either with pulmonary metastasis (2) or unresectable primaries (1) and were treated with radiation therapy and/or palliative Adriamycin‐based chemotherapy. Patients treated with curative intent underwent a variety of surgical resections dictated by tumor location and size. Four patients received postoperative radiation therapy to a median dose of 60 Gy, for positive surgical margins (2), high‐grade histology (1) or a recurrent lesion (1). Five‐year overall survival in patients treated surgically was 87.5%. A single mortality occurred in a patient with a recurrent high‐grade lesion who failed at local, regional, and distant sites. Median follow‐up of survivors was 73 months.Conclusion: The clinical behavior of hemangiopericytomas appears to be related to their histological grade. Aggressive local therapy including surgery and radiation therapy appears to be effective in providing tumor control.
Outcome of Frontal Sinus Obliteration
Authors: Mendians Andrew E. , Marks Steven C. 
Published: November 2003

AbstractObjectives: To evaluate the indications, technique, and results after long‐term follow‐up of osteoplastic frontal sinusectomy with fat obliteration.Study Design: A retrospective review of a series of consecutive patients using objective and subjective outcome assessment.Methods: A retrospective chart review was conducted of all patients undergoing osteoplastic flap procedure with obliteration between July 1, 1991, and July 1, 1997. Each patient also completed a symptom questionnaire rating the degree of symptoms both before and after surgery using a 10‐point scale. The results were tabulated and analyzed for statistical significance.Results: Twenty osteoplastic flap procedures to obliterate the frontal sinus were reviewed. The average patient age was 41 years, with the average duration of follow‐up being 40.2 months. No surgical failures were noted; one patient underwent a negative reexploration. One surgical and one medical complication are reported. Statistically significant improvement was noted in overall symptoms, headache, congestion, drainage, and frequency of infections when the preoperative to the postoperative symptom scores were compared (P < .001).Conclusions: Based on these results, the use of the osteoplastic flap in the obliteration of the frontal sinus continues to be an option in the era of endoscopic treatment of frontal sinus disease, particularly in endoscopic failures and chronic frontal sinus pain.
A Comparative Model: Reaction Time Performance in Sleep‐Disordered Breathing Versus Alcohol‐Impaired Controls
Authors: Powell Nelson B. , Riley Robert W. , Schechtman Kenneth B. , Blumen Marc B. , Dinges David F. , Guilleminault Christian 
Published: November 2003

AbstractObjectives/Hypothesis: Patients with sleep‐disordered breathing have reaction time deficits that may lead to catastrophic accidents and loss of life. Although safety guidelines do not exist for unsafe levels of sleepiness, they have been established for unsafe levels of alcohol consumption. Since reaction time performance is altered in both, we prospectively used seven measures of reaction time performance as a comparative model in alcohol‐challenged normal subjects with corresponding measures in subjects with sleep‐disordered breathing.Study Design: Institutional Review Board‐approved, nonrandomized prospective controlled study.Methods: Eighty healthy volunteers (29.1 ± 7.5 y of age, 56.3% female subjects) performed four reaction time trials using a psychomotor test at baseline and at three subsequent rising alcohol‐influenced time points. The same test without alcohol was given to 113 subjects (47.2 ± 10.8 y of age, 19.3% female subjects) with mild to moderate sleep‐disordered breathing.Results: Mean blood alcohol concentrations (BACs) in the alcoholinfluenced subjects at baseline and three trials were 0, 0.057, 0.080, and 0.083 g/dL. The sleep‐disordered subjects had mean respiratory disturbance indices of 29.2 events per hour of sleep. On all seven reaction time measures, their performance was worse than that of the alcohol subjects when BACs were 0.057 g/dL. For three of the measures, the sleep‐disordered subjects performed as poorly as or worse than the alcohol subjects when alcohol levels were 0.080 g/dL. These results could not be explained by sex or age differences.Conclusion: The data demonstrate that sleep‐disordered subjects in this study (with a mean age of 47 y) with mild to moderate sleep‐disordered breathing had worse test reaction time performance parameters than healthy, nonsleepy subjects (with a mean age of 29 y) whose BAC is illegally high for driving a commercial motor vehicle in California. This comparative model points out the potential risks of daytime sleepiness in those with sleep‐disordered breathing relative to a culturally accepted standard of impairment.
Lamina Propria of the Mucosa of Benign Lesions of the Vocal Folds
Authors: Dikkers Frederik G. , Nikkels Peter G.J. 
Published: November 2003

AbstractObjective/Hypothesis: To demonstrate a correlation between the duration and specific pattern of trauma of benign lesions of the vocal folds and their histopathologic appearance. Benign lesions of the vocal folds have various macroscopic appearances. Investigations demonstrate characteristic histopathologic features for three clinically well‐defined lesions: 1) vocal fold polyps, 2) Reinke edema, and 3) vocal fold nodules. It is expected that additional histological stainings can contribute to additional insight into the pathophysiology of these lesions.Study Design: Retrospective.Methods: Histological stainings were used to study the constitution of the lamina propria of the mucosa: Verhoeff‐van Gieson, Masson trichrome, alcian blue and alcian blue after pretreatment with hyaluronidase.Results: Estimation of the age of a lesion was not possible. Specific observations: 1) accumulation of hyaluronic acid around vessels occurred uniquely in polyps and 2) transverse orientation of elastic fibers was more often seen in vocal fold nodules. Combinations of histopathologic findings were specific to the lesion.Conclusions: The additional stainings support our previous observations, but had no additional discriminating value in making a histopathologic diagnosis.
Noninvasive Imaging of Human Oral Mucosa in Vivo by Confocal Reflectance Microscopy
Authors: White W. Matthew , Rajadhyaksha Milind , González Salvador , Fabian Richard L. , Anderson R. Rox 
Published: November 2003

AbstractObjectives/Hypothesis: To study the microscopic anatomy of normal oral tissues in vivo using confocal reflectance microscopy (CRM). This novel and noninvasive imaging modality can define and characterize healthy oral mucosa and thus this work serves as the foundation for studying oral diseases in vivo.Study Design: This was a pilot observational cohort study comparing noninvasive CRM images with histology.Materials and Methods: Lip and tongue mucosa were imaged by CRM in six healthy human subjects. In CRM living tissue is illuminated by a laser source and backscattered (or reflected) light is collected by a detector. Image contrast is determined by natural differences in refractive indices of organelles and other subcellular structures within the tissues. Gray‐scale images were displayed in real‐time on a video monitor and represented horizontal (en face) optical sections through the tissue. Motion of the oral tissue relative to the objective lens was minimized with a tissue stabilizer. After imaging, biopsies were taken from the same site of lip mucosa to correlate noninvasive confocal images with conventional histology.Results: Confocal images correlated well with conventional histology, both qualitatively (visual analysis) and quantitatively (stereology). Imaging was possible up to depths of 490 and 250 μm in the lip and tongue, respectively. Cells and organelles including nuclei, circulating blood cells, and extracellular matrix were clearly observed.Conclusion: CRM provides details of normal human oral mucosa at the cellular level without the artifacts of histological processing, and thus has the potential for further development and use in clinical practice as a diagnostic tool for the early detection of oral cancer and precancer.
Activity Influences on Neuronal Connectivity Within the Auditory Pathway
Authors: Niparko John K. 
Published: November 2003

AbstractHypothesis: Sensorineural hearing loss may be associated with altered patterns of neuronal connections within the central auditory pathway.Study Design: The cat auditory system was used to address the relative importance of impulse traffic within the auditory nerve in maintaining central nervous system connections.Methods: Acute, unilateral deafness was induced by tetrodotoxin intoxication of cochlear hair cells. Analysis focused on the structural patterns of contact between auditory nerve endings called end bulbs of Held and their target neurons. Specifically, end bulb morphology and target cell size within the cochlear nucleus were examined. Highly specialized synaptic contacts at this junction provide a powerful site for study.Results: The principal finding was that abolished activity in the auditory nerve caused nerve endings to assume a different shape, typified by more branching and smaller terminal swellings. The new shape is one typically associated with only a subpopulation of fibers in normal‐hearing cats‐those exhibiting a high‐threshold, low‐spontaneous activity profile. This result implies that abolished activity alters patterns of nerve fiber contact with second‐order neurons. Tetrodotoxin produced differential effects on subpopulations of target neurons within the brain‐stem and is interpretable on the basis of “weighing” synaptic inputs. Second‐order neurons that receive large axosomatic inputs from their parent fiber were significantly smaller than neurons that receive small, axodendritic terminals. Thus, attenuated auditory activity may produce differential effects across the auditory pathway, thereby disrupting the normal balance of inputs into synaptic stations.Conclusions: Impulse traffic is a critical factor in the interaction between the ear and central auditory stations and appears necessary for the maintenance of key synapses. As hearing disorders with impaired comprehension may be modeled by studies of auditory deafferentation, these observations extend the possibility that changes in central neuronal connections underlie reduced capabilities for processing restored auditory input.
Methods of Teaching Stapedectomy
Authors: Levenson Mark J. 
Published: November 2003

AbstractObjectives: Establish a better method of teaching residents stapes surgery, with the goal of improving surgical outcome.Study Design: A stapes surgery teaching module was developed with specific criteria to evaluate resident performance. A prospective study of stapes surgery performed by teaching module trained residents was compared with a retrospective review of stapes surgery performed by non‐teaching module trained residents.Methods: Four residents naive to stapes surgery were assigned to a stapes surgery teaching module. Stapedectomy of 20 temporal bones per resident, with six 3‐hour laboratory sessions, was performed. Laser (C02 and argon) as well as mechanical techniques were used. Specific scoring criteria were applied to measure performance. Results of actual stapes surgery of teaching module trained residents were compared with those of a comparable group of non‐teaching module trained residents.Results: Laser techniques in the laboratory resulted in statistically significantly better scores by defined criteria than mechanical techniques. Results of actual stapes surgery performed by teaching module trained residents demonstrated a trend toward better surgical results, although this was not statistically significant.Conclusions: Graded operative experience and standard temporal bone surgery courses may not adequately prepare residents for stapes surgery. A teaching module with criteria to evaluate performance better prepares residents for this delicate procedure. Lasers provide a significant advantage in the laboratory model and should be used by residents at surgery. Residents not wishing to perform stapes surgery because of career pathway should be encouraged to turn over their cases to fellow residents.
Determination of the Levels of Expression of Sarcolectin and Calcyclin and of the Percentages of Apoptotic But Not Proliferating Cells to Enable Distinction Between Recurrent and Nonrecurrent Cholesteatomas
Authors: Choufani Georges , Mahillon Virginie , Decaestecker Christine , Lequeux Thomas , Danguy André , Salmon Isabelle , Gabius Hans‐Joachim , Hassid Sergio , Kiss Robert 
Published: November 2003

AbstractObjectives: To investigate in a series of cholesteatomas 1. whether subgroups of cholesteatomas with specific proliferative/apoptotic features exhibit distinct differentiation markers and 2. whether these different subgroups identified at the biological level relate to specific groups of clinically identified cholesteatomas.Study Design: Analysis of 55 cholesteatomas resected by the same surgeon, by means of canal wall up and canal wall down surgical procedures.Methods: Two differentiation markers were used: biotinylated sarcolectin (to identify sarcolectin‐binding sites) and a monoclonal antibody directed against calcyclin (which is the S100A6 protein). The growth pattern in cholesteatomas was characterized at three distinct levels: 1. the cell proliferation level determined by means of the MIB‐1 antibody, which enables the Ki‐67 cell‐cycle‐related antigen to be identified on archival material; 2. the apoptosis level determined by means of the in situ labeling of nuclear DNA fragmentation (TUNEL staining); and 3. the p53 tumor suppressor gene‐related product determined by means of p53 immunohistochemistry.Results: The cholesteatomas that exhibited the highest proportion of apoptotic cells were those which exhibited the highest level of sarcolectin‐binding sites (i.e., sialic acids). In contrast, the cholesteatomas exhibiting the lowest level of both proliferation and apoptosis showed the highest level of calcyclin. Recurrent cholesteatomas can be identified from nonrecurrent ones on the basis of three features, namely, the level of apoptotic cells, the way in which the apoptotic cells are distributed (i.e., homogeneously vs. heterogeneously), and the percentage of calcyclin‐positive cells.Conclusions: The present data emphasize the existence of distinct subgroups of cholesteatomas identifiable at both cell kinetic and differentiation levels. Some of the biological variables used here to identify distinct biological subgroups of cholesteatomas in turn enabled some biological variables to be identified, so making it possible to classify the cholesteatomas in terms of recurrence versus nonrecurrence.
Evolving Experience With Direct Puncture Therapeutic Embolization for Adjunctive and Palliative Management of Head and Neck Hypervascular Neoplasms
Authors: Chaloupka John C. , Mangla Sundeep , Huddle Daniel C. , Roth Toni C. , Mitra Sanchayeeta , Ross Douglas A. , Sasaki Clarence T. 
Published: November 2003

AbstractObjectives: The use of percutaneous, direct puncture therapeutic embolization (DPTE) of hypervascular head and neck neoplasms is a relatively new modality that may be used to supplement or supplant conventional endovascular transarterial embolization. Although the preliminary clinical experience reported by a single group has been favorable, extensive case series experience is lacking. This prompted us to review our recent clinical experience with these techniques to determine safety, efficacy, and emerging role in the overall neurointerventional therapeutic armamentarium.Study Design: A retrospective analysis of the previous 34 consecutive cases of hypervascular tumors undergoing DPTE referred to our service for therapeutic devascularization was performed.Methods: Complete case record review was undertaken. Twenty‐six of 34 cases involved DPTE of head and neck neoplasms. Conventional diagnostic angiography was performed for therapeutic planning and to assist in precise localization. When performed, standard microcatheter transarterial embolization techniques were used either before or after attempted DPTE. Cyanoacrylate embolic mixtures (n‐butyl cyanoacrylate [NBCA], lipiodol, powdered tungsten) were used in 21 of 24 cases, and absolute ethanol in 3 of 24. Direct puncture angiography of the targeted tumor neovasculature was always performed before DPTE.Results: Twenty‐four of 26 cases had technically successful DPTE. Combined transarterial embolization with DPTE was used in 16 of 24 cases, although for the last 12 cases, 9 were treated predominantly or exclusively by DPTE. There were no major or minor clinical complications, and there was one asymptomatic technical complication. Total or near‐total devascularization was achieved in all cases. All preoperative cases had excellent hemostasis within the resected tumor bed.Conclusions: Our results lend further support to the safety and efficacy of DPTE in the management of hypervascular neoplasms of the head and neck. With our increasing experience, this technique is evolving into a primary therapeutic modality for optimal tumor devascularization.
Complications in Skull Base Surgery for Malignancy
Authors: Donald Paul J. 
Published: November 2003

AbstractObjectives: To review a consecutive series of skull base surgeries, establish the rate of complications, and outline their prevention and management.Study Design: A retrospective review of 107 consecutive intracranial/extracranial operations performed for malignancy that transgresses the skull base.Methods: The hospital charts of 107 operations performed on 98 patients at the University of California at Davis Medical Center. The type of operation, cause of death, and complications were noted.Results: The complication rate was 50.5%. Forty‐eight patients had no complications. There were six perioperative deaths. The most common surgical complications were cerebrospinal fluid leak (11.2%), meningitis (4.8%), and wound breakdown (15%). The most common medical complications were pneumonia (6.5%), cardiac disturbance (4.7%), and electrolyte imbalance (3.7%). The only prior treatment that was accompanied by a significant increase in complications was previous surgery.Conclusions: Complications occurred in approximately half of the patients who had cranial base surgery for the intracranial spread of head and neck cancer. The perioperative death rate is less than 4%. The major complications were at an acceptable rate.