Biomedical subjects

S D Schaefer

Publications and source records attributed to S D Schaefer.

At least 19 recordsLinked to original sources

PubMed1992

The acute management of external laryngeal trauma. A 27-year experience.

The acute care of 139 consecutive patients with external laryngeal trauma over a 27-year period is reported. This article represents an effort to periodically reevaluate our care of this relatively infrequent injury and to share our changes and refinements in treatment. This series provides the means to test and establish basic principles in the acute care of external laryngeal trauma because (1) the number of years encompassed by the article, (2) most patients were managed by one physician, (3) the relative consistency of management principles throughout the series, and (4) the delivery of trauma care in Dallas County, Texas, reflects a broad sampling of this injury within the geographic area.

Biomechanical Phenomena↗

PubMed1992

Multichannel electromyographic observations in spasmodic dysphonia patients and normal control subjects.

Spasmodic dysphonia is primarily a disorder of vocalization. Increasing evidence, however, suggests that individuals with this disorder comprise a heterogeneous population characterized by abnormal motor control throughout the vocal tract. Multichannel simultaneous electromyography was performed on 11 spasmodic dysphonia patients and 10 normal awake subjects to investigate both the distribution of neuromotor abnormality within the vocal tract (eg, intrinsic and extrinsic laryngeal muscles, tongue, and palate) and the contribution of activation of higher central nervous system centers to observed abnormality. Experimental tasks ranged from vegetative (quiet breathing) to simple linguistic (short sentences). Digitized electromyographic signals were analyzed to compute the amplitude envelope and extract a set of parameters that represent amplitude characteristics. Electrode insertions were cross-validated by quantitative analysis of patterns of activation across selected reference tasks and by traditional qualitative methods. Between-group differences were found for measures of normalized median and peak token amplitudes. These differences are both task- and measure-dependent. Results highlight the complex and interactive effects of muscle, task, and quantitative measures on between-group differences.

Adult↗

PubMed1991

Heterogeneity in spasmodic dysphonia. Neurologic and voice findings.

Spasmodic dysphonia is a disturbance of phonation with laryngeal spasms. We report voice and neurologic examination findings in 45 subjects. Neurologic abnormalities were found in 32 subjects (71.1%). Rapid alternating movement abnormalities, weakness, and tremor were common. Incoordination and spasticity were rare. Lower extremity findings were frequent. Abnormalities were bilateral. Spasmodic dysphonia severity was related to age. Type, severity, and duration of vocal symptoms were not different for subjects with or without neurologic abnormalities. Vocal tremor was more frequent in neurologically abnormal subjects. Involvement of a pallidothalamic-supplementary motor area system could account for neurologic findings, brain imaging findings, and clinical heterogeneity. The view emerging is that spasmodic dysphonia is a manifestation of disordered motor control involving systems of neurons rather than single anatomical sites.

Adult↗

PubMed1991

The treatment of acute external laryngeal injuries. 'State of the art'.

Guidelines are presented for the management of acute external laryngeal trauma based on personal experience and basic principles evolved over the past two decades. Accurate assessment of the extent of injury has permitted stratification of treatment ranging from observation to open reduction and internal fixation of the laryngeal skeleton. Results are often predictable and frequently lead to restoration of the voice and airway.

Diagnosis↗

PubMed1991

Culture-positive allergic fungal sinusitis.

Allergic Aspergillus sinusitis is a well-defined clinical and histologic entity, although surprisingly few reported cases have yielded any fungal growth on culture. Taking advantage of recent changes in the identification and classification of certain groups of fungi, we were able to identify a specific fungal organism in 19 of 22 consecutive patients with a histologic diagnosis of allergic fungal sinusitis over the past 2 1/2 years. Aspergillus was found in only one patient, while an organism in the family of dematiaceous fungi was found in 18 patients. Of these patients, the genus Bipolaris was the most commonly represented, while Exserohilum, Curvularia, and Alternaria species were seen with less frequency. Thus, it appears that Aspergillus may not be the most common etiologic agent in allergic "Aspergillus" sinusitis. Allergic fungal sinusitis is not unusual and its incidence may be increasing. On initial clinical evaluation it may be easily mistaken for malignancy or invasive fungal disease with the potential for overly aggressive treatment. Preoperative suspicion of allergic fungal sinusitis based on clinical and roentgenographic findings along with careful communication with the mycology laboratory about the possibility of dematiaceous fungal growth are necessary for proper diagnosis.

Adolescent↗

PubMed1991

Laryngeal reaction time profiles in spasmodic dysphonia: relationship to cortical electrophysiologic abnormality.

This study combines measures of linguistic and vocal performance and long-latency auditory electrophysiology to investigate task-dependent variability in spasmodic dysphonia (SD). Linguistic performance was evaluated using several measures of relatively complex linguistic ability (i.e., discourse analysis). Vocal performance was evaluated by measuring acoustic laryngeal reaction time (LRT) for tasks that differ in complexity. Normal structure of the cortex and subcortex was confirmed by magnetic resonance imaging. Cortical function was measured using multichannel quantitative auditory evoked potentials (AEPs). As a group, SD subjects who demonstrated subtle linguistic deficits also demonstrated prolonged LRT for the complex task and repeated and persistent auditory electrophysiologic abnormalities over the anterior quadrant of the left hemisphere. As a group, linguistically normal SD subjects demonstrated no significant increase in LRT for the complex task and no recurrent electrophysiologic abnormalities over the left anterior cortex relative to normal controls. Results support a neurogenic origin of SD and suggest that some aspects of inter- and intrasubject variability may be related to differences in loci and magnitude of cortical abnormalities.

Adult↗

PubMed1991

Laryngeal electromyographic activity in adductor and abductor spasmodic dysphonia.

Vocal symptoms in spasmodic dysphonia (SD) range from strain-strangle phonation and glottal-stop phonatory breaks of adductor SD to breathy phonation and aspirate phonatory breaks of abductor SD. Many SD subjects show both symptom types. Heterogeneity in vocal symptoms contributes to controversy surrounding the etiology(s) of SD. Acoustic/perceptual analyses of vocal symptoms are inconclusive in resolving this controversy. This investigation moves the search for distinguishing features of adductor and abductor SD to the level of neuromuscular control and analysis of intrinsic laryngeal muscle (adductor and abductor) activity. Subjects rated perceptually as primarily adductor or abductor SD sustained production of vegetative gestures and isolated speech sounds (/i/ and /s/). Qualitative and quantitative analyses of electromyographic signals recorded from thyroarytenoid (TA) failed to differentiate SD subjects by symptom type. Analysis of TA and posterior cricoarytenoid (PCA) activity in one abductor SD revealed high levels in both muscles during production of the voiced vowel. Data suggest that a possible explanation for symptom heterogeneity in SD is the relation between disrupted neuromotor input to laryngeal muscles and reflexive or conscious compensations constrained by laryngeal biomechanics.

Adult↗

PubMed1991

Laryngeal electromyography.

Laryngeal electromyography (EMG) is simultaneously a powerful clinical and investigative tool. EMG may be diagnostic and prognostic in cases of laryngeal or vagus nerve injury and can differentiate between vocal cord fixation and paralysis. EMG also is being used to help unravel complex laryngeal neural and muscle physiology. Basic principles of EMG, techniques of EMG limited to three muscles--the thyroarytenoid, the posterior cricoarytenoid, and the cricothyroid, and pitfalls of this procedure are discussed within this article.

Electromyography↗

PubMed1991

Use of CT scanning in the management of the acutely injured larynx.

An update regarding the selective application of CT scanning in acute laryngeal trauma is presented for a period encompassing 9 years. A study group of 16 patients from a larger population of 52 patients was identified as having undergone CT scanning as part of their clinical management. A rationale is presented for the use of scanning in certain injuries, and the outcome of medical and surgical treatment is discussed.

Adult↗

PubMed1990

Evidence for cortical dysfunction in spasmodic dysphonia: regional cerebral blood flow and quantitative electrophysiology.

Cortical function was evaluated in 26 subjects with spasmodic dysphonia. Quantitative topographic electrophysiologic mapping (QTE) was employed to provide quantitative analyses of EEG spectra and auditory and visual long-latency evoked potentials. Single-photon emission computed tomography (SPECT) of the cerebral transit of Xenon-133 was used to evaluate regional cerebral blood flow. Left hemispheric abnormalities in cortical function were found by both techniques in 10 subjects and by at least one technique in 18 subjects. Right hemispheric abnormalities were observed by both techniques in 8 subjects and by at least one technique in 18 subjects. Most patients with cortical dysfunction in one hemisphere had cortical dysfunction in the other, while only 4 subjects had unilateral lesions as found by one of the two techniques. Eight subjects were normal by all measurements. Underlying structural abnormalities were detected by magnetic resonance imaging in 5/24 subjects. However, functional abnormalities (SPECT or QTE) were not observed at sites of structural abnormalities. SPECT and QTE were significantly related in identification of left hemispheric dysfunction (p = .037) with a trend in the right hemisphere (p = .070), and a significant congruence of SPECT and QTE findings occurred in the left anterior cortical quadrant (p = .011). These findings indicate that dysfunction of cortical perfusion and/or cortical electrophysiology is associated with spasmodic dysphonia in the majority of subjects studied.

Adult↗

PubMed1990

Systems architecture for quantification of dynamic myoelectric and kinematic activity of the human vocal tract.

This paper describes a systems architecture useful for scientific investigations that require the acquisition and analysis of multiple, time-synchronous signals in large volume. The architecture has recently been developed by this group to enhance our capability to research and quantify central nervous system function in the production of normal and pathologic speech. The architecture utilizes modern advances in desktop microcomputers and has been designed so that vocal motor control laboratories (or similar settings) with modest funding can more fully participate in comprehensive investigations of speech production. Research experiments organized with this architecture may involve many more subjects and measures than previously possible without significant increases in time and personnel resources. This paper will demonstrate the technique and practicality of this architecture as it is being used to successfully guide research to map hierarchic central nervous system regions of involvement in two speech disorders: spasmodic dysphonia and stuttering. The architecture has broad usefulness to many areas of otolaryngology and health science.

Adult↗

PubMed1990

Endoscopic management of frontal sinus disease.

Depending on the pathologic process, the treatment of frontal sinus disease has consisted of obliteration or ablation of the sinus, or restoration of drainage into the nose. Intranasal endoscopic enlargement of the frontal recess and ostium, and removal of disease from the medial aspect of the frontal sinus offers a minimally invasive alternative to previous operations in selected patients. To better understand the indications, limitations, and potential problems with this operation, our experience with endoscopic frontal sinustomy in 36 patients over a 30-month period is reported. During the follow-up period, 21 patients had complete resolution of all symptoms, 11 patients were improved but had at least one episode of sinusitis or headache postoperatively, and 3 patients were worse, 2 of whom required frontal sinus obliteration for control of disease. Although endoscopic frontal sinusotomy appears to be a useful alternative to traditional frontal sinus procedures in selected patients, the reader is cautioned that such surgery is technically difficult and has not yet stood the test of time required of any frontal sinus operation.

Adolescent↗

PubMed1989

Surgical management of nasopharyngeal angiofibroma involving the cavernous sinus.

Involvement of the cavernous sinus by juvenile nasopharyngeal angiofibroma represents a therapeutic challenge. We present our experience over the past 5 years with the surgical management of six cases of juvenile nasopharyngeal angiofibroma involving this site. Three of six patients had involvement of the medial aspect of the cavernous sinus and tumor was removed using a midline extracranial approach. Of three remaining patients, two had invasion of the medial and inferior margin of the cavernous sinus and one represented a recurrent lesion. The tumor in these three cases was resected using a combined frontotemporal and lateral infratemporal fossa approach. An extracranial recurrence occurred in one patient, and the remaining five patients have had no evidence of recurrent disease 12 to 71 months following surgery. Morbidity has been limited to trismus, facial hypesthesia, and serous otitis media.

Adolescent↗

PubMed1989

Microvascular invasion and survival in cancer of the oral cavity and oropharynx.

Although the presence of squamous cell carcinoma within the peritumoral vascular spaces of primary lesions of the oral cavity and oropharynx has been statistically linked to regional lymph node metastases, the association of this finding with disease control and survival has not been well demonstrated. To evaluate this relationship, we have reviewed the clinical and histopathologic features of 65 consecutive cases of previously untreated T2 or greater squamous cell carcinoma of these sites managed by simultaneous surgical treatment of the primary lesion and regional lymph nodes. Of all the histopathologic features of the primary lesion studied, vascular invasion had the greatest impact on survival, as confirmed by both univariate and multivariate analysis. In addition, vascular invasion correlated statistically with local recurrence, neck recurrence, and distant metastasis.

Adult↗

PubMed1989

Acute management of laryngeal trauma. Update.

The management of 120 laryngeal injury patients at a major trauma center over 23 years is presented in the form of two patient populations. The first population consists of 52 previously analyzed and reported laryngeal trauma patients who served as the basis for the subsequent refinement of treatment of a second population of 68 patients. Collectively, these patients form a series unique in that 1) it comprises the largest number of such injuries treated at one institution, 2) the management principles remained the same throughout the entire 23 years, and 3) the majority of the patients were managed by one physician. The experience gained from these patients is examined in the hope of resolving prevailing controversies about the treatment of the acutely injured larynx.

Aged↗

PubMed1989

Endoscopic paranasal sinus surgery: indications and considerations.

Recently, American otolaryngologists have become increasingly interested in endoscopic paranasal sinus surgery. This trend has been beneficial, because it has enhanced the understanding of the anatomy and pathophysiology of the sinuses. However, as with the introduction of any new surgical technique, it takes both time and experience to acquired the skills necessary to perform this procedure. To evaluate the state of endoscopic sinus surgery, we analyzed the experience of one of the authors with 100 consecutive patients undergoing therapeutic endoscopic sinus surgery over 23 months. With an average follow-up of 5 months (range: less than 1 month to 20 months), 14 patients had minor complications. The most common complication was synechia between the middle turbinate and the lateral nasal wall (six patients), resulting in revision surgery in four patients. Eighty-three patients were judged as having significantly improved after surgery, while ten were improved but had one episode of sinusitis postoperatively. The results of this series suggest that endoscopic paranasal sinus surgery is an efficacious advance in the treatment of sinusitis, given the limitations discussed in this report.

Adolescent↗

PubMed1989

Endoscopic total sphenoethmoidectomy.

Endoscopic total sphenoethmoidectomy is a procedure reserved for the patient with extensive paranasal sinus disease. Candidates for this operation should have radiographic evidence of pansinusitis and be refractory to medical and lesser surgical management. Given these criteria, total sphenoethmoidectomy with frontal sinusotomy and antrostomy offers an excellent treatment for this patient population.

Endoscopy↗

PubMed1988

A randomized trial for outpatient management of peritonsillar abscess.

In order to compare the efficacy of permucosal needle drainage with that of incision and drainage in the outpatient management of peritonsillar abscess, 52 patients with aspiration-proven peritonsillar abscess were entered into a randomized, prospective protocol. A symptomatic scale scoring system was employed to evaluate treatment results. In the needle drainage group, 92% (22/24) were cured with a single aspiration. Ninety-three percent (26/28) of the patients in the incision and drainage group were cured on the initial attempt. The remainder of the patients in both groups were cured with a single retreatment. Only one patient required hospitalization, and no patients required tonsillectomy to resolve the abscess. These data indicate that outpatient permucosal needle drainage of peritonsillar abscess is an acceptable, inexpensive treatment comparing favorably with incision and drainage.

Adolescent↗