Biomedical subjects

D H Slavit

Publications and source records attributed to D H Slavit.

At least 19 recordsLinked to original sources

PubMed2000

Effects of thyroplasty type I on vocal fold vibration.

OBJECTIVE: To ascertain effects of medialization thyroplasty on vocal fold vibration in glottic incompetence dysphonia. STUDY DESIGN: Quantitative videostroboscopic glottic measurements and vocal function study were perioperatively undertaken in 20 patients undergoing Isshiki's thyroplasty type I. METHODS: In digitized images, the glottal area, glottal width, posterior glottal width, and amplitude over an entire glottal cycle were measured and normalized by membranous vocal fold length. The ratio of closed phase to total phase of vibratory cycle was calculated from the data of the glottal area and the glottal width at the middle point of the membranous vocal fold. Well-accepted acoustic, aerodynamic, and perceptual measures analyzed vocal function. RESULTS: Glottal area and glottal width were reduced after surgery. While preoperative closure of glottal area was incomplete in all 20 patients, incomplete closure was obtained in 16 patients after surgery. In these 16 patients, closure of glottal width at the middle point of the membranous vocal fold was complete, whereas a posterior glottal gap remained in 14 patients. Closed phase over one cycle of glottal width waveform and amplitude of vocal fold vibration were increased after surgery. Glottal area, glottal width, posterior glottal width, and closed phase over one cycle of glottal width waveform correlated with vocal function measures. CONCLUSIONS: Thyroplasty type I reduces a glottal gap and increases closed phase over one cycle and amplitude of vocal fold vibration, although a posterior glottal gap remains. With the improved glottic vibration, thyroplasty type I provides more efficient phonation in patients with glottic incompetence dysphonia.

Adolescent↗

PubMed1999

Phonosurgery in the elderly: a review.

Surgery in the elderly requires a knowledge of the changes in the larynx that take place with aging. In the elderly larynx, there are changes in the elastin and collagen fibers within the lamina propria. There is also thinning and atrophy of the mucous membranes and atrophy of the mucous glands. Common disorders are vocal fold atrophy, sulcus vocalis, glottic incompetence, and vocal fold edema. A reduction in the number of lymphatic channels is responsible for the vocal fold edema. Vocal fold atrophy is responsible for the increase in pitch that is frequently heard in elderly men. Other common conditions in the elderly include vocal fold nodules, polyps, and Reinke's edema. The most common phonosurgical procedures performed in the elderly are vocal fold surgery for benign pathology and laryngeal structure surgery for glottic incompetence. Microsurgical techniques on benign vocal fold lesions aim to avoid injury to the transitional layer, which is rich in fibroblasts. Although the superficial layer of the lamina propria involves less fibroblastic activity, any surgical manipulation of the lamina propria can influence the vibratory properties of the vocal folds, particularly when the basement membrane zone is manipulated. The alterations in phonosurgical techniques used in the elderly are the result of histologic changes in the vocal folds and altered wound healing. Functional voice disorders often develop to compensate for the structural changes in the larynx. Correction of hyperfunctional or abnormal functional technique is as important as phonosurgical correction of vocal fold pathology.

Aged↗

PubMed1998

Influence of size and etiology of glottal gap in glottic incompetence dysphonia.

This study investigates the relationship between glottal gap and vocal function in patients with glottic incompetence dysphonia. Twenty patients with vocal fold paralysis (VFP), 17 patients with vocal fold atrophy (VFA), and five patients with sulcus vocalis (SV) were examined. Glottal gap area at the most closed point of vibration was measured using digitized videostroboscopic images. Glottal gap area was correlated with acoustic and aerodynamic measures of vocal function. Patients with VFP had the largest glottal gaps and had significantly worse vocal function than did the patients with VFA or SV. Regardless of groups, however, where glottal gap size was similar, there was no difference in vocal function. Therefore vocal function was mainly influenced by glottal gap size, not by whether glottic incompetence was the result of VFP, VFA, or SV.

Acoustics↗

PubMed1998

The role of outfracture in correcting post-rhinoplasty nasal obstruction.

Post-rhinoplasty nasal osbtruction is often related to narrowing in the region of the nasal valve. Correction of this obstruction can include inferior turbinectomy, septoplasty spreader grafts and nasal valvuloplasty. The authors have seen cases of severe valve stenosis related to infracture after osteotomy which did not respond to any of the aforementioned procedures. These patients were treated with revision osteotomy with outfracture. We discuss patient selection and surgical technique for revision osteotomy with outfracture as well as a cadaver dissection demonstrating the effects of infracture and outfracture on valve area. The clinical results, based on patient satisfaction and pre- and postoperative photographs, are presented. Revision osteotomy with outfracture should be included in the surgeon's armamentarium for the treatment of post-rhinoplasty nasal obstruction.

Adult↗

PubMed1997

Acoustic characteristics of rough voice: subharmonics.

This study investigates the relationship between rough voice and the presence of subharmonics, which correspond to smaller yet distinct peaks located between two consecutive harmonic peaks in the power spectrum. Spectrum analysis was undertaken in 389 pathologic voices, of which 20 had subharmonics. Although all 20 voices had roughness perceptually, 8 had normal jitter and/or shimmer. The degree of roughness had a significant inverse relationship with the frequency of subharmonics. By digital signal processing, sound samples with various types of subharmonics were synthesized and perceptually analyzed. Power and frequency of subharmonics in the synthesized sound also had significant relationships with the degree of roughness. Rough voice is acoustically characterized not only by jitter and shimmer but also by the presence of subharmonics in the power spectrum. Subharmonics are important acoustic properties for objective evaluation of rough voices.

Adult↗

PubMed1997

Vocal fold atrophy: quantitative glottic measurement and vocal function.

Videostroboscopic glottic measurements and vocal function were evaluated in 41 vocal fold atrophy patients with bowed vocal folds. The amount of bowing in the resting position and the glottal gap area and vibratory amplitude during phonation were measured from digitized videostroboscopic images. Vibratory amplitude was not decreased on atrophic vocal folds. With the same amount of total bowing, the glottal gap area for bilateral atrophy was smaller than for unilateral atrophy. These results suggest that vocal fold atrophy is not disadvantageous to thyroplasty type I, and that bilateral procedures may produce a better outcome than a unilateral procedure in the treatment of bilateral atrophy. Acoustic, aerodynamic, and perceptual parameters of vocal function were measured. The acoustic high-frequency power ratio and the H-index correlated with the glottal gap area. The mean flow rate correlated with the amount of bowing. The degree of dysphonia was related to the size of the glottal gap and bowing.

Adult↗

PubMed1997

Swallowing and pharyngeal function in postoperative pharyngeal cancer patients.

This study examines the pharyngeal phase of swallowing after the resection of pharyngeal cancer, and focuses on the pharynx as a functional organ. The purpose of the study was to obtain information on both reconstruction and rehabilitation in cases of surgically treated pharyngeal cancer. The records of 21 consecutive patients who underwent surgical treatment of oropharyngeal and hypopharyngeal squamous cell carcinoma between 1990 and 1993 were reviewed. Functional results following surgery were graded on a numerical scale in three categories: pharyngeal swallow, laryngeal and lower airway protection, and oral alimentation. Three treatment groups were observed: group 1 = transoral excision with primary closure (six patients); group 2 = composite resection with primary closure (nine patients); and group 3 = composite resection with deltopectoral or pectoralis major flap closure (six patients). Comparison of pharyngeal swallow and laryngeal protection functions showed no significant difference between the three groups. However, oral alimentation performance in group 1 was significantly better than in group 3, and groups 1 and 2 achieved a similar level. In patients with T3 and T4 tumors postoperative function was poor and no difference in postoperative function was demonstrated between patients undergoing reconstruction with primary closure and patients undergoing reconstruction with deltopectoral or pectoralis major flaps. Patients with T3 and T4 tumors experienced impaired postoperative function regardless of the method of reconstruction used. This is not a condemnation of the surgical treatment of advanced pharyngeal tumors, but rather a suggestion that other reconstruction techniques be considered.

Aged↗

PubMed1996

Quantitative criteria for predicting thyroplasty type I outcome.

The purpose of this study was to ascertain the relation between preoperative glottal gap and postoperative vocal function in thyroplasty type I. Twenty-two of 64 patients who underwent thyroplasty type I between 1987 and 1994 were studied. In preoperative digitized laryngostroboscopic images, the glottal-gap, width (GGW), shape, and area were examined at the maximum closure of vibration and normalized by membranous vocal-fold length (MVFL). Postoperative vocal function analysis was performed with aerodynamic and acoustic measurements and compared with preoperative videostroboscopic images. In patients with preoperative posterior GGW of less than 10% of MVFL, postoperative vocal function was significantly better than in other patients. Although thyroplasty type I is an excellent medialization technique, it may need to be combined with a posterior closure procedure in patients with large posterior gaps.

Adult↗

PubMed1996

Quantitative videostroboscopic measurement of glottal gap and vocal function: an analysis of thyroplasty type I.

The goal of surgical medialization of the vocal fold is to attain complete glottic closure. The purpose of this study is to quantify the glottal gap and to examine the relationship between glottal gap and vocal function perioperatively in thyroplasty type I. Glottal gap area was measured in 20 patients at the point of maximum closure of vocal fold vibration in digitized laryngeal stroboscopic images and was normalized by the square of vocal fold length. Glottal gap area thus measured was correlated with results obtained from well-accepted acoustic, aerodynamic, and perceptual measures of vocal function. The glottal gap was significantly reduced after thyroplasty type I. In patients with small preoperative glottal gaps, the amplitude of vocal fold vibration was significantly improved. This study verifies that quantitative videostroboscopic measurement of the glottal gap is a useful means of objective evaluation of glottic incompetence and of the results of thyroplasty type I.

Acoustics↗

PubMed1996

Turbinoplasty for concha bullosa: a non-synechiae-forming alternative to middle turbinectomy.

A large pneumatized middle turbinate (concha bullosa) may require surgical reduction. Partial middle turbinectomy, especially when done simultaneously with uncinectomy and ethmoidectomy, results in an increased risk for adhesion formation in the middle meatus. Turbinoplasty is a procedure that results in a significant reduction of the width of the middle turbinate without injuring its mucosal surfaces. A 4-year experience with this procedure showed almost complete elimination of the synechiae problem.

Humans↗

PubMed1995

Reconstruction of caudal end of septum. A case for transplantation.

OBJECTIVE: To examine the results of complete removal and reconstruction of the caudal end of the septum with emphasis on long term success. DESIGN: A case series reviewing the surgical outcome of 45 consecutive cases of transplantations for severely deformed of absent caudal ends of the septum. After at least 18 months, all 45 patients were given a postoperative evaluation. SETTING: All procedures were performed at Mayo Clinic, Rochester, Minn. PATIENTS: Forty-five patients (36 male and nine females) ranged in age from 7 to 78 years, with a mean age of 38 years. Twenty-seven patients had severe caudal end deformities, and 18 patients had absent or flaccid caudal end. OUTCOME MEASURES: Subjective assessment included the opinion of the patient, rhinologic examination, and photographic analysis. Anterior mask rhinomanometry was performed to measure nasal resistance. Clinically noted complications were documented when present. RESULTS: Subjectively, 36 (80%) of the 45 patients reported "normal" nasal breathing, and seven patients (15.6%) reported improved nasal breathing. Objective preoperative and postoperative rhinomanometry data, available in 28 cases, was related to the subjective findings. The longevity of the caudal end transplant was confirmed by reviewing the data from the 33 patients who were followed up more than 1 year. Ninety percent of the patients were free of complications. CONCLUSION: Objective and subjective results showed excellent long-term results. The caudal end of the nasal septum can be removed safely and reconstructed.

Adolescent↗

PubMed1995

Open slope quotient: a new glottographic parameter.

This study introduces a new objective measurement of the vibratory pattern termed the open slope quotient (OSQ). This parameter is based on the maximum slope of the photoglottographic waveform during glottal opening. Using an excised canine larynx model, the electroglottographic and photoglottographic waveforms, sound intensity, and subglottic pressure were recorded as vocal fold tension; glottic width and airflow rate were systematically varied. Multiple regression analysis of the data from nine larynges revealed OSQ to be inversely related to glottic width (p < 0.001) and vocal fold tension (p < 0.001) and directly related to glottic resistance (p < 0.001) and subglottic pressure (p < 0.001). The OSQ was better correlated with glottic width, subglottic pressure, and glottic resistance than speed quotient. OSQ is related to the velocity of vocal fold opening and laryngeal resistance. OSQ may also be related to vocal fold stiffness.

Animals↗

PubMed1994

Arytenoid adduction and type I thyroplasty in the treatment of aphonia.

Arytenoid adduction is a procedure used to medialize the paralyzed vocal fold, closing the posterior glottis. Isshiki type I thyroplasty allows medialization of the anterior membranous vocal fold. Using the arytenoid adduction, in combination with Isshiki type I thyroplasty as needed, five patients were treated for aphonia. Surgical results were evaluated with voice recordings, electroglottography, and photoglottography. Jitter ratio, shimmer ratio, and signal-to-noise ratio were measured. Laryngeal stroboscopy and glottography were used to assess the mucosal wave and vibratory nature of the vocal folds. After operation, vocal function was restored. Analysis of data from these five aphonia patients revealed improved glottic phonatory function. The arytenoid adduction in combination with the Isshiki type I thyroplasty is an effective technique for aphonia caused by a significant posterior glottic gap with unilateral vocal-cord paralysis.

Arytenoid Cartilage↗

PubMed1993

Teflon granulomas and overinjection of Teflon: a therapeutic challenge for the otorhinolaryngologist.

We have found that Teflon granulomas and the overinjection of Teflon with the resulting laryngeal dysfunction, although uncommon, present a challenge to the otorhinolaryngologist, due in large part to the inflammatory reaction to the injected Teflon. This report addresses the management of 16 patients (12 women and 4 men) treated surgically for symptoms secondary to Teflon granulomas or vocal folds that had been overinjected with Teflon. The presenting symptoms varied and included airway obstruction, cough, choking, swallowing difficulties, and dysphonia. In each case the granuloma and Teflon were removed endoscopically via a lateral cordotomy. A second procedure to address dysphonia due to vocal cord lateralization was frequently required and presents the challenge for the surgeon to select the appropriate procedure and time of intervention. The results of this retrospective review suggest that resolution of inflammatory changes and fibrosis subsequent to Teflon removal requires significant lengths of time and that thyroplasty techniques provide a means for medialization without reintroduction of the original inflammatory material.

Adult↗

PubMed1992

Physiologic assessment of arytenoid adduction.

Arytenoid adduction as described by Isshiki is a surgical technique used to improve vocal quality by adducting the arytenoid cartilage of a paralyzed vocal fold, medializing the fold, and closing the posterior glottic aperture. Surgical results of this operation were evaluated by preoperative and postoperative voice recordings, laryngoscopy, and stroboscopy. Objective measurements of vocal jitter, shimmer, and signal to noise ratio were done to assess changes in the vibratory patterns, and analysis of data from 12 patients revealed improved glottic function postoperatively. Often an anterior medialization procedure, primarily a type I thyroplasty, was used to supplement the posterior medialization achieved by adduction of the arytenoid. Arytenoid adduction is recommended as an effective and reliable treatment for posterior glottic insufficiency.

Adult↗

PubMed1992

Noninvasive technique for estimating subglottic pressure and laryngeal efficiency.

The clinical assessment of aerodynamic parameters is important in the physiology and pathophysiology of laryngeal function. Vocal efficiency is among these objective measurements and can be calculated from simultaneous recordings of subglottic pressure, airflow, and sound intensity. Modern techniques allow us to accurately determine sound intensity and airflow. However, methods to determine subglottic pressure are either invasive or laborious. We have evaluated a noninvasive, indirect method to determine subglottic pressure by using a technique based on the interruption of transglottic airflow during phonation. The correlation between the indirectly acquired subglottic pressure measured in the oral cavity by using this technique and the subglottic pressure obtained directly by translaryngeal puncture in human volunteers was highly significant in 35 trials (r = .92, p less than .01). This study describes a reliable technique for the noninvasive measurement of subglottic pressure, sound intensity, and airflow.

Glottis↗

PubMed1992

Effect of BAEP monitoring on hearing preservation during acoustic neuroma resection.

We measured the effect of brainstem auditory evoked potential (BAEP) monitoring on hearing preservation in acoustic neuroma resection in 90 consecutive patients with monitoring compared with 90 historical controls matched for tumor size and preoperative hearing status. In small tumors (less than 2 cm), BAEP monitoring was associated with a higher rate of hearing preservation and a greater chance that the hearing preserved was clinically useful. Changes in the BAEP intraoperatively showed a good correlation with postoperative hearing status.

Evoked Potentials, Auditory, Brain Stem↗

PubMed1991

Auditory monitoring during acoustic neuroma removal.

Preservation of hearing has become attainable for patients with small acoustic neuromas. Brain-stem auditory evoked response was monitored intraoperatively in 60 patients undergoing acoustic neuroma surgery via the posterior fossa approach. The overall rate of hearing preservation was 30% in the monitored group and 20% in 60 patients who were matched for tumor size and preoperative hearing level and underwent the same surgical procedure but without intraoperative brain-stem auditory evoked response monitoring. The rate of hearing preservation was correlated with tumor size: with tumors less than or equal to 1 cm, hearing was preserved in 82% of monitored and 36% of unmonitored patients; hearing was not preserved with tumors larger than 3 cm. Intraoperative brain-stem auditory evoked response monitoring appears to have improved the preservation of hearing during removal of small tumors.

Adolescent↗