Retinopathy develops at similar glucose levels but higher HbA1c levels in people with black African ancestry compared to white European ancestry: evidence for the need to individualize HbA1c interpretation

AIMS

To examine the association of HbA_1c and glucose levels with incident diabetic retinopathy according to black African or white European ancestry.

METHODS

In this retrospective cohort study of 202 500 US Veterans with diabetes (2000-2014), measures included HbA_1c , outpatient random serum/plasma glucose, and incident retinopathy [conversion from negative to ≥2 positive evaluations (ICD-9 codes), without a subsequent negative].

RESULTS

At baseline, the study population had a mean age of 59.3 years, their mean BMI was 31.9 kg/m² , HbA_1c level was 57 mmol/mol (7.4%) and glucose level was 8.8 mmol/l, and 77% were of white European ancestry (white individuals) and 21% of black African ancestry (black individuals). HbA_1c was 0.3% higher in black vs white individuals (P < 0.001), adjusting for baseline age, sex, BMI, estimated glomerular filtration rate (eGFR), haemoglobin, and average systolic blood pressure and glucose. Over 11 years, incident retinopathy occurred in 9% of black and 7% of white individuals, but black individuals had higher HbA_1c , glucose, and systolic blood pressure (all P < 0.001); adjusted for these factors, incident retinopathy was reduced in black vs white individuals (P < 0.001). The population incidence of retinopathy (7%) was associated with higher mean baseline HbA_1c in individuals with black vs white ancestry [63 mmol/mol (7.9%) vs 58 mmol/mol (7.5%); P < 0.001)], but with similar baseline glucose levels (9.0 vs 9.0 mmol/l; P = 0.660, all adjusted for baseline age, sex and BMI).

CONCLUSIONS

Since retinopathy occurs at higher HbA_1c levels in black people for a given level of average plasma glucose, strategies may be needed to individualize the interpretation of HbA_1c measurements.

Impact of mismatches in HbA1c vs glucose values on the diagnostic classification of diabetes and prediabetes

AIMS

To determine whether HbA_1c mismatches (HbA_1c levels that are higher or lower than expected for the average glucose levels in different individuals) could lead to errors if diagnostic classification is based only on HbA_1c levels.

METHODS

In a cross-sectional study, 3106 participants without known diabetes underwent a 75-g oral glucose tolerance test (fasting glucose and 2-h glucose) and a 50-g glucose challenge test (1-h glucose) on separate days. They were classified by oral glucose tolerance test results as having: normal glucose metabolism; prediabetes; or diabetes. Predicted HbA_1c was determined from the linear regression modelling the relationship between observed HbA_1c and average glucose (mean of fasting glucose and 2-h glucose from the oral glucose tolerance test, and 1-h glucose from the glucose challenge test) within oral glucose tolerance test groups. The haemoglobin glycation index was calculated as [observed - predicted HbA_1c ], and divided into low, intermediate and high haemoglobin glycation index mismatch tertiles.

RESULTS

Those participants with higher mismatches were more likely to be black, to be men, to be older, and to have higher BMI (all P<0.001). Using oral glucose tolerance test criteria, the distribution of normal glucose metabolism, prediabetes and diabetes was similar across mismatch tertiles; however, using HbA_1c criteria, the participants with low mismatches were classified as 97% normal glucose metabolism, 3% prediabetes and 0% diabetes, i.e. mostly normal, while those with high mismatches were classified as 13% normal glucose metabolism, 77% prediabetes and 10% diabetes, i.e. mostly abnormal (P<0.001).

CONCLUSIONS

Measuring only HbA_1c could lead to under-diagnosis in people with low mismatches and over-diagnosis in those with high mismatches. Additional oral glucose tolerance tests and/or fasting glucose testing to complement HbA_1c in diagnostic classification should be performed in most individuals.

Racial differences in performance of HbA1c for the classification of diabetes and prediabetes among US adults of non-Hispanic black and white race

AIM

To characterize differences between black and white people in optimal HbA_1c thresholds for diagnoses of diabetes and prediabetes.

METHODS

Data were included from the National Health and Nutrition Examination Survey, 2005-2014. Black and white adults (age 18-70 years) who underwent an oral glucose tolerance test and had available fasting plasma glucose, 2-h plasma glucose and HbA_1c measurements were eligible for inclusion. Diabetes or prediabetes status was defined by fasting plasma glucose and 2-h plasma glucose using American Diabetes Association criteria. Classification of diabetes, prediabetes and dysglycaemia by HbA_1c was evaluated for a range of HbA_1c thresholds, with optimal thresholds defined as those values that maximized the sum of sensitivity and specificity (Youden's index).

RESULTS

In 5324 black (32.3%) and white (67.7%) individuals, Youden's index (optimal) thresholds for HbA_1c were ≥42 mmol/mol (6.0%) and ≥39 mmol/mol (5.7%) for discriminating diabetes vs non-diabetes, ≥ 44 mmol/mol (6.2%) and ≥39 mmol/mol (5.7%) for discriminating diabetes vs prediabetes (excluding normoglycaemia), ≥39 mmol/mol (5.7%) and ≥37 mmol/mol (5.5%) for discriminating dysglycaemia vs normoglycaemia, and ≥39 mmol/mol (5.7%) and ≥37 mmol/mol (5.5%) for discriminating prediabetes vs normoglycaemia (excluding diabetes), in black and white people, respectively.

CONCLUSIONS

Consistently higher optimal HbA_1c thresholds in black people than in white people suggest a need to individualize HbA_1c relative to glucose levels if HbA_1c is used to diagnose diabetes and prediabetes.

Invasive Nasal Alternariosis

Alternaria, a naturally occurring plant pathogen, may rarely cause infection in immunocompromised patients. This report describes a case of invasive alternariosis in a 33-year-old patient with acute leukemia.

Influence of Vocal Fold Scarring on Phonation: Predictions from a Finite Element Model

Objectives:

A systematic study of the influence of vocal fold scarring on phonation was conducted. In particular, phonatory variables such as fundamental frequency, oral acoustic intensity, and phonation threshold pressure (PTP) were investigated as a function of the size and position of the laryngeal scar.

Methods:

By means of a finite element model of vocal fold vibration, the viscoelastic properties of both normal and scarred vocal fold mucosae were simulated on the basis of recent rheological data obtained from rabbit and canine models.

Results:

The study showed that an increase in the viscoelasticity of the scarred mucosa resulted in an increase in fundamental frequency, an increase in PTP, and a decrease in oral acoustic intensity. With regard to positioning of the scar, the PTP increased most significantly when the scar was within ±2 mm of the superior-medial junction of the vocal folds.

Conclusions:

The systematic data obtained in this investigation agree with the general clinical experience. In the future, these findings may be further validated on human subjects as newly emerging technologies such as linear skin rheometry and optical coherence tomography allow the histologic and viscoelastic properties of the normal and scarred vocal fold mucosae to be measured in the clinic.

Growth Factor Therapy for Vocal Fold Scarring in a Canine Model

Vocal fold scarring remains a therapeutic challenge. Hepatocyte growth factor (HGF) has strong antifibrotic activity and has proved to have therapeutic potential in restoration of scar tissues such as liver cirrhosis and lung fibrosis. The present study aimed to clarify the effects of HGF injection into scarred vocal folds in a canine model. Canine vocal folds were stripped unilaterally and treated with intracordal injection of saline solution (sham group), HGF (HGF group), or HGF with cultured autologous normal vocal fold fibroblasts (Fb/HGF group) 1 month after injury. The larynges were harvested 6 months after the initial injury and then subjected to vibratory and histologic examination. The results of vibratory examinations in the excised larynx setup revealed that phonation threshold pressure significantly increased and vocal efficiency was significantly reduced in all treated groups as compared to normal data obtained from normal canine larynges. However, the HGF group presented much better results than both the sham and Fb/HGF groups in terms of mucosal wave amplitude and incidence of vocal fold bowing, glottal incompetence, and phase asymmetry. The histologic data indicated a significant increase of collagen in both the sham and Fb/HGF groups, while normal levels of collagen were found in the HGF group. Tissue contraction of the lamina propria was also observed in both the sham and Fb/HGF groups, but was barely detectable in the HGF group. Although the HGF-treated vocal folds appeared to require more driving forces for vibration, HGF might prevent excessive collagen deposition and tissue contraction and thus reduce the effects of scarring on the vibratory properties of the vocal folds. From these data it is concluded that HGF has considerable potential in the treatment of vocal fold scarring.

Morphological and Functional Changes of Human Vocal Fold Fibroblasts with Hepatocyte Growth Factor

Fibroblasts produce extracellular matrix and play an important role in wound healing and scarring. Hepatocyte growth factor (HGF) has strong antifibrotic activity, and has been suggested to have therapeutic potential for treatment of fibrotic diseases. In the present in vitro study, morphological and functional changes of human vocal fold fibroblasts with HGF were examined by transmission electron microscopy and enzyme-linked immunosorbent assay to help clarify the potential use of HGF in the prevention or treatment of vocal fold scarring. The HGF stimulated the production of hyaluronic acid (HA) and decreased the production of collagen type I from the fibroblasts in Reinke's space (FbRS), whereas fibronectin production was not affected. The HGF also changed the shape of the FbRS from an oval shape toward a spindle and stellate shape, and developed Golgi apparatus (GA) and rough endoplasmic reticulum (rER) in the FbRS. The fibroblasts in the macula flava (FbMF) presented with much more production of HA and collagen type I than did FbRS, and were more frequently formed in a stellate shape with well-developed GA and rER. The HGF decreased the production of collagen type I from the FbMF, but barely affected the FbMF in terms of the shape of the cells, the development of GA and rER, or the production of HA. These results were interpreted to suggest that the FbMF are not as susceptible to HGF as are FbRS. On the contrary, HGF appeared to activate the FbRS and modify the function. The increased HA and decreased collagen type I production from the FbRS suggest that HGF may be useful in the prevention or treatment of fibrotic vocal fold scarring.

Regeneration of Aged Vocal Folds with Basic Fibroblast Growth Factor in a Rat Model: A Preliminary Report

Aged vocal folds have been reported to have dense collagen deposition and decreased hyaluronic acid (HA) in the lamina propria. These characteristics are thought to contribute to vocal problems that occur with age (presbyphonia). To restore better viscoelasticity to aged vocal folds, an intervention that might increase HA and decrease collagen production from aged vocal fold fibroblasts would appear to be a potentially useful approach. Our previous in vitro study has revealed that basic fibroblast growth factor (bFGF) consistently stimulates HA production and decreases collagen production from aged rat vocal fold fibroblasts. The present in vivo study examined the effects of intracordal injection of bFGF into aged rats' vocal folds in terms of restoration of HA and collagen distribution in the lamina propria. We injected bFGF transorally into the lamina propria of (unilateral) vocal folds. The injection was repeated 4 times weekly, and rats were painlessly sacrificed 1 week, 1 month, and 2 months after the final injection. Histologic examination revealed that bFGF significantly increased the HA content of the lamina propria up to 2 months, but showed no effect on collagen, even after 2 months. Because it might take longer for excessive collagen to be degraded, further studies are necessary to clarify the long-term effect on collagen. A drug delivery system for bFGF also needs to be developed to maximize its effect in the future. The present study suggested at least a positive effect of bFGF in restoring the HA content in the aged vocal fold lamina propria.

In vivo markers of inflammatory response in recent-onset schizophrenia: a combined study using [(11)C]DPA-713 PET and analysis of CSF and plasma

Several lines of evidence suggest aberrant immune response in schizophrenia, including elevated levels of cytokines. These cytokines are thought to be produced by activated microglia, the innate immune cells of the central nervous system. However, increase in translocator protein 18 kDa (TSPO), a marker of activated glia, has not been found in patients with chronic schizophrenia using second-generation radiotracers and positron emission tomography (PET)-based neuroimaging. In this study we focused on patients with recent onset of schizophrenia (within 5 years of diagnosis). Quantified levels of TSPO in the cortical and subcortical brain regions using the PET-based radiotracer [(11)C]DPA-713 were compared between the patients and healthy controls. Markers of inflammation, including interleukin 6 (IL-6), were assessed in the plasma and cerebrospinal fluid (CSF) in these participants. We observed no significant change in the binding of [(11)C]DPA-713 to TSPO in 12 patients with recent onset of schizophrenia compared with 14 controls. Nevertheless, the patients with recent onset of schizophrenia showed a significant increase in IL-6 in both plasma (P<0.001) and CSF (P=0.02). The CSF levels of IL-6 were significantly correlated with the levels of IL-6 in plasma within the total study population (P<0.001) and in patients with recent onset of schizophrenia alone (P=0.03). Our results suggest that increased levels of IL-6 may occur in the absence of changed TSPO PET signal in the brains of medicated patients with recent onset of schizophrenia. Future development of PET-based radiotracers targeting alternative markers of glial activation and immune response may be needed to capture the inflammatory signature present in the brains of patients with early-stage disease.

Ten-year beverage intake trends among US preschool children: rapid declines between 2003 and 2010 but stagnancy in recent years

BACKGROUND

It has been previously reported that total energy intake among US preschool children (ages 2-5 years) decreased between 2003-2004 and 2009-2010. However, little is known about how intakes of beverages among US preschoolers (ages 2-5 years) changed from 2003-2004 to 2011-2012.

OBJECTIVES

This paper examines changes in intakes of key beverages during this period, as well as how eating location (at home or away from home) and source (store vs. others) may have contributed to these changes.

METHODS

Cross-sectional day one dietary data among children ages 2-5 years from the National Health and Nutrition Examination Survey 2003-2004, 2005-2006, 2007-2008, 2009-2010 and 2011-2012 were used. Survey-weighted mean intakes by survey year, eating location and source were computed for total sugar-sweetened beverages (SSBs), milks, 100% juice, low/no-calorie beverages, 10 key beverages, total beverages and total foods. Means were compared using two-tailed z-tests with Bonferroni corrections (α < 0.05).

RESULTS

Between 2003-2004 and 2011-2012, among 2-5 year olds, total caloric intake fell by 132 kcal d(-1) , with intakes of beverages falling by 55 kcal d(-1) . Decreases in intakes of total SSBs (-57 kcal d(-1) ), fruit-flavoured or juice drinks containing <100% juice (juice drinks) (-37 kcal d(-1) ), caloric soft drinks (-13 kcal d(-1) ) and >1% fat, low-sugar milk (-42 kcal d(-1) ) were among the major changes. By eating location, total beverage intake at home fell by 73 kcal d(-1) . By source, total beverage intake from stores fell by 106 kcal d(-1) . Changes in intakes occurred primarily between 2003-2004 and 2009-2010, as there were no significant differences in beverage intakes between 2009-2010 and 2011-2012. Intakes of total calories (+49 kcal d(-1) ) and calories from foods (+53 kcal d(-1) ) trended upward between 2009-2010 and 2011-2012, but changes were not significant.

CONCLUSIONS

These findings suggest improvements in the diets of preschoolers between 2003-2004 and 2009-2010, of which stores were a major contributor.

Combined type IIIB with bilateral type I thyroplasty for pitch lowering with maintenance of vocal fold tension

To evaluate type IIIB thyroplasty using the excised larynx bench apparatus and determine how altering vocal fold contour by performing bilateral medialization of the inferior vocal fold affects phonation. This procedure could be performed in patients for whom pitch lowering is desirable, such as female-to-male transsexuals or male patients with mutational falsetto in whom intensive voice therapy was insufficient. Aerodynamic, acoustic, and high-speed videokymographic data were collected for nine larynges at three subglottal pressure inputs for each of three conditions: normal; type IIIB thyroplasty; and combined type IIIB with modified bilateral type I thyroplasty intended to create a more rectangular glottal configuration. Each larynx served as its own control. Phonation threshold flow (p = 0.005), phonation threshold power (p = 0.031), and airflow varied across conditions with highest values for type IIIB thyroplasty and lowest for the combined procedure. Fundamental frequency was significantly different (p < 0.001), decreasing by approximately 100 Hz from control to type IIIB trials, and then by approximately 15 Hz from IIIB to combined procedure trials. Vibratory amplitudes and intrafold phase difference were highest for type IIIB trials. Addition of bilateral inferior medialization to type IIIB thyroplasty provided some further decrease in frequency, but mostly served to increase tension, reduce airflow, and produce a vibratory pattern which more closely mirrored control trials. Exploration of this combined procedure in patients may be warranted if not completely satisfied with the results from type IIIB thyroplasty alone.

Secondary Tracheoesophageal Puncture In-Office Using Seldinger Technique

Objective

Evaluate the safety and efficacy of in-office secondary tracheoesophageal puncture (TEP) technique using transnasal esophagoscopy (TNE) and the Seldinger technique in conjunction with a cricothyroidotomy kit for placement.

Study Design

Case series with chart review.

Setting

Academic medical center.

Subject and Methods

A retrospective chart review was performed on 83 subjects who underwent in-office secondary TEP. Variables that were examined included disease site, staging, histologic diagnosis, extent of resection and reconstruction, chemoradiation, functional voice status (as assessed by speech pathologist in most recent note), and complications directly related to the procedure.

Results

Eighty-three individuals from our institution met our criteria for in-office secondary TEP from 2005 to August 2012. Of these, 97.6% (81/83) had no complications of TEP. The overall complication rate was 2.4% (2/83). Complications included bleeding from puncture site and closure of puncture site after dislodgement of prosthesis at the time of puncture. Fluent conversational speech was achieved in 69.9% of all patients (58/83), and an additional 19.3% (16/83) achieved functional/intelligible speech; of those, 3.6% (3/83) were unable to achieve fluent conversational speech due to anatomic defects from previous surgery.

Conclusion

An in-office TEP can be safely performed using the Seldinger technique with direct visualization using TNE, despite the extent of resection or reconstruction, with functional speech outcomes comparable to other studies available in the literature.

Gender associations in head and neck squamous cell carcinoma (HNSCC)

e16010

Background: The primary objective of this analysis was to examine the association of gender with various presentation and outcome parameters in HNSCC. Methods: We queried the head and neck cancer (HNC) database at the University of Wisconsinand examined selected clinical, treatment and outcome data for all patients (pts) treated consecutively during the 10-year period (1/01-12/10). Results: From a total of 1,108 HNC pts, we identified 965 with SCC histology, including 252 women (26.1%) and 713 men (73.9%). Women were slightly older at presentation (mean age 62 vs. 60, p = 0.03); 29.6% of women vs. 19.6% of men were 70 years or older. There were no differences in race distribution. Smoking and drinking habits were frequently reported in both sexes, although seen more frequently in men. 74.1% of women vs. 83.1% of men had smoked cigarettes (p=0.003), while 74.9% and 90.6% respectively had consumed alcohol (p<0.0001). 16.3% women never smoked or drank in comparison to 4.6% in men (p<0.0001). There was a difference in primary tumor site distribution between genders (p=0.0003). Oral cavity (41.3%) and larynx (23%) were the most common sites in women vs. oropharynx (31.1%) and larynx (24.8%) in men. There appeared to be no difference in tumor T stage. However, more men presented with N2/3 (51.7% vs. 39.9%, p=0.01) and stage IV (63.1% vs. 53.2%, p=0.04). For initial treatment, more men received multi-modality therapy (56.2% vs. 48.4%, p=0.009) while more women received surgery as sole therapy (37.3% vs. 27.1%). Overall, 72.7% of men vs. 62.3% of women received radiation (XRT); 36.5% and 26.2% respectively received concurrent chemoradiation. There were no differences in baseline performance status, total XRT dose (mean 65.8 Gy), fractionation (mean 33), XRT technique (3D conformal, linac-based IMRT or tomotherapy), or chemotherapy delivered. Recurrence free outcome was achieved equally in both genders at the primary tumor site (~80%), neck (~84%) and distant sites (~88%). Median survival was 89.5 months in women and 84.2 months in men (p=0.65). Conclusions: Although there were no differences in overall survival,our analysis suggests that some gender differences may exist in risk factors and clinical presentation for HNSCC pts. Further study is warranted.

Prospective multi-arm evaluation of surgical treatments for vocal fold scar and pathologic sulcus vocalis

OBJECTIVES/HYPOTHESIS

The purpose of this study was to compare the clinical effectiveness of type I thyroplasty, injection laryngoplasty, and graft implantation for the treatment of vocal fold scar and pathologic sulcus vocalis.

STUDY DESIGN

Prospective, multi-arm, quasi-experimental research design.

METHODS

Twenty-eight patients with newly diagnosed vocal fold scar and/or pathologic sulcus vocalis were assigned to one of three treatment modalities: type I thyroplasty (n = 9), injection laryngoplasty (n = 9), and graft implantation (n = 10). Psychosocial, auditory-perceptual, acoustic, aerodynamic, and videostroboscopic data were collected pretreatment and at 1, 6, 12, and 18 months posttreatment.

RESULTS

Type I thyroplasty and graft implantation both resulted in reduced voice handicap with no concomitant improvement in auditory-perceptual, acoustic, aerodynamic, or vocal fold physiologic performance. Injection laryngoplasty resulted in no improvement on any vocal function index. Patients who underwent graft implantation exhibited the slowest improvement trajectory across the 18-month follow-up period.

CONCLUSIONS

A persistent challenge in this area is that no single treatment modality is successful for the majority of patients, and there is no evidence-based decision algorithm for matching a given treatment to a given patient. Progress therefore requires the identification and categorization of predictive clinical features that can drive evidence-based treatment assignment.

Differentiating between adductor and abductor spasmodic dysphonia using airflow interruption

OBJECTIVES/HYPOTHESIS

To measure the laryngeal resistance (R(L)), subglottal pressure (P(s)), and mean flow rate (MFR) of adductor (ADSD) and abductor (ABSD) spasmodic dysphonia patients using the airflow interrupter.

METHODS

The R(L) of six ABSD and seven ADSD patients was measured using the airflow interrupter, a noninvasive device designed to measure MFR and P(s) via mechanical balloon valve interruption. Subjects performed 10 trials at each of two intensity levels, with each trial consisting of a sustained /a/ during which phonation was interrupted for 500 ms. Laryngeal resistance was calculated as subglottal pressure divided by airflow.

RESULTS

Mean R(L) for the ADSD and ABSD subtypes at 65 dB were 24.78 cmH(2)O/L/s and 14.51 cmH(2)O/L/s, respectively (P = .04). Mean R(L) at 70 dB were 40.02 cmH(2)O/L/s and 15.84 cmH(2)O/L/s (P = .014). P(s) for the ADSD and ABSD subtypes at 65 dB were 10.23 cmH(2)O and 8.32 cmH(2)O, respectively (P = .582). At the 70 dB level, P(s) were 12.39 cmH(2)O and 11.78 cmH(2)O (P = .886). MFR for the ADSD and ABSD subtypes at 65 dB were 435 mL/s and 746 mL/s (P = .205). Mean MFR at 70 dB were 518 mL/s and 848 mL/s (P = .198).

CONCLUSIONS

Noninvasive measurements of R(L) may be useful for differentiating between ADSD and ABSD. This simple objective test, which produces a quantitative output, could be used to evaluate laryngeal function in patients with spasmodic dysphonia.

Comparative study of vocal outcomes with silicone versus Gore-Tex thyroplasty

OBJECTIVES

We examined vocal outcomes of patients who underwent type I thyroplasty for unilateral vocal fold paralysis. Specifically, the vocal outcomes were compared between 15 patients whose thyroplasties were performed with silicone and 15 patients whose thyroplasties were performed with Gore-Tex.

METHODS

The examined clinical characteristics did not differ significantly between the groups. The vocal outcomes were evaluated by aerodynamic and acoustic measurements.

RESULTS

Aerodynamic examination indicated significant postoperative improvements in the maximum phonation time and mean flow rate in both groups. Shimmer was significantly improved only in the Gore-Tex group. A direct comparison between groups showed no significant difference in the degree of improvement of the vocal parameters, except for a significant improvement in the noise-to-harmonics ratio in the Gore-Tex group. The duration of surgery was significantly less in the Gore-Tex group than in the silicone group.

CONCLUSIONS

Gore-Tex thyroplasty is considered to be comparable to silicone thyroplasty in terms of postoperative vocal outcomes. Gore-Tex thyroplasty enables a less invasive procedure with a shorter surgical duration and easier adjustment of medialization due to its flexibility.

Recommendations of the Neurolaryngology Study Group on laryngeal electromyography

The Neurolaryngology Study Group convened a multidisciplinary panel of experts in neuromuscular physiology, electromyography, physical medicine and rehabilitation, neurology, and laryngology to meet with interested members from the American Academy of Otolaryngology Head and Neck Surgery, the Neurolaryngology Subcommittee and the Neurolaryngology Study Group to address the use of laryngeal electromyography (LEMG) for electrodiagnosis of laryngeal disorders. The panel addressed the use of LEMG for: 1) diagnosis of vocal fold paresis, 2) best practice application of equipment and techniques for LEMG, 3) estimation of time of injury and prediction of recovery of neural injuries, 4) diagnosis of neuromuscular diseases of the laryngeal muscles, and, 5) differentiation between central nervous system and behaviorally based laryngeal disorders. The panel also addressed establishing standardized techniques and methods for future assessment of LEMG sensitivity, specificity and reliability for identification, assessment and prognosis of neurolaryngeal disorders. Previously an evidence-based review of the clinical utility of LEMG published in 2004 only found evidence supported that LEMG was possibly useful for guiding injections of botulinum toxin into the laryngeal muscles. An updated traditional/narrative literature review and expert opinions were used to direct discussion and format conclusions. In current clinical practice, LEMG is a qualitative and not a quantitative examination. Specific recommendations were made to standardize electrode types, muscles to be sampled, sampling techniques, and reporting requirements. Prospective studies are needed to determine the clinical utility of LEMG. Use of the standardized methods and reporting will support future studies correlating electro-diagnostic findings with voice and upper airway function.

Use of lasers in laryngeal surgery

Lasers are a relatively recent addition to laryngeal surgery. Since their invention, laser use and applications have expanded rapidly. In this article, we discuss the benefits and disadvantages of lasers for different procedures, as well as ways to overcome commonly faced clinical problems. The use of lasers in surgery has offered a time- and cost-efficient alternative to cold surgical techniques, and has been used in the treatment of numerous laryngeal pathologies, including stenoses, recurrent respiratory papillomatosis, leukoplakia, nodules, malignant laryngeal disease, and polypoid degeneration (Reinke's edema). However, lasers can incur adjacent tissue damage and vocal fold scarring. These problems can be minimized through understanding the mechanisms by which lasers function and correctly manipulating the parameters under a surgeon's control. By varying fluence, power density, and pulsation, tissue damage can be decreased and lasers can be used with greater confidence. The various types of lasers and their applications to the treatment of specific pathologies are reviewed with the intention of helping surgeons select the best tool for a given procedure. Recent applications of lasers to treat benign laryngeal lesions and severe laryngomalacia demonstrate that additional research must be conducted to realize the full potential of this surgical tool.

A-P positioning of medialization thyroplasty in an excised larynx model

HYPOTHESIS

Posterior positioning of medialization thyroplasty provides the best acoustic and aerodynamic outcomes.

STUDY DESIGN

Ex vivo excised canine larynx.

METHODS

Unilateral thyroplasty windows were cut in the thyroid cartilages of 10 excised canine larynges. Each larynx was mounted on an artificial lung and the vocal fold opposite the thyroid window was adducted by medializing its arytenoid cartilage. Then, medialization thyroplasty was simulated with a probe placed anterior, central, and posterior in the thyroid window. The glottal area, airway reduction, medialization force, phonation threshold pressure and flow, aerodynamic power, intensity, efficiency, jitter, shimmer, and signal-to-noise ratio (SNR) were measured at each medialization position.

RESULTS

Posterior medialization probe placement minimized the glottal area, provided the best voice as determined by perturbation measures and SNR, reduced the work of phonation, and increased efficiency. Anterior and middle probe placement minimized the work of phonation but provided only modest gains in sound quality and decreased sound intensity. Medializing the vocal fold with posterior probe placement required twice as much force as central and anterior probe placement.

CONCLUSIONS

The results suggest that posterior medialization provides the greatest improvement in acoustic parameters and efficiency in patients who can tolerate the airway reduction. Middle and anterior medialization can decrease work of phonation, but in this experiment objective improvement in sound quality was limited. Subtle changes in displacement shim contour, especially in middle and anterior locations, have a substantial impact on voice outcome, affirming the value of intraoperative voice assessment.

Cidofovir efficacy in recurrent respiratory papillomatosis: a randomized, double-blind, placebo-controlled study

OBJECTIVES

We performed a prospective, double-blind, placebo-controlled, longitudinal adjuvant therapy trial to determine the efficacy of cidofovir in the treatment of severe recurrent respiratory papillomatosis (RRP). Although results of case series suggest that cidofovir may decrease the frequency and rapidity of papilloma regrowth, no blinded placebo-controlled studies have demonstrated efficacy.

METHODS

Adults and children (n = 19) with aggressive RRP received either active drug (cidofovir) or placebo. When surgical intervention was needed, drug or placebo was injected into affected areas after surgical removal of disease. The following measures were made at baseline and at 2-month intervals for the course of 12 months: Derkay papilloma severity grading scale, Voice Handicap Index, Health-Related Quality of Life, and total number of procedures performed over 12 months.

RESULTS

At 2- and 12-month follow-ups, there was a significant (p < .05) improvement in the Derkay Severity Score within the cidofovir and placebo groups, but no difference between groups, and no difference between groups in the number of procedures performed. Significant improvement was found in Voice Handicap Index scores in the cidofovir group at the 12-month follow-up. No differences were seen in Health-Related Quality of Life.

CONCLUSIONS

A randomized, blinded, placebo-controlled trial is necessary in the study of RRP, because the natural history of the disease can include remissions and reactivations. We found a significant improvement in the Derkay Severity Score 12 months after the baseline assessment in patients treated with cidofovir. This effect, however, was also seen in the placebo group. Accordingly, we were unable to provide proof of efficacy of cidofovir in the treatment of RRP.

Voice handicap evaluation of patients with pathologic sulcus vocalis

OBJECTIVES

The purpose of this study was to characterize the psychosocial impact of dysphonia on patients with pathologic sulcus vocalis by use of the Voice Handicap Index (VHI).

METHODS

The VHI was administered to 15 patients (11 women and 4 men) with pathologic sulcus vocalis. The VHI subscale and total scores were compared with previously published data from individuals with no history of dysphonia and from patients with vocal fold scar. Additional comparisons were performed for patients with unilateral sulcus versus bilateral sulci, type II sulcus versus type III sulcus, and sulcus with concomitant vocal fold scar versus sulcus without concomitant scar.

RESULTS

The VHI scores for patients with pathologic sulcus vocalis were significantly greater than those for individuals with no history of dysphonia and for patients with vocal fold scar. In addition, significantly greater VHI scores were observed for patients with sulcus vocalis with concomitant scar versus those with sulcus alone.

CONCLUSIONS

These data suggest that pathologic sulcus vocalis can be a severely handicapping condition, particularly in the presence of concomitant scar.

Clinical Evaluation of Parkinson???s-Related Dysphonia

OBJECTIVES

Nearly one third of patients with idiopathic Parkinson's disease (IPD) cite dysphonia, characterized subjectively as causing a harsh and breathy voice, as their most debilitating deficit. Medical or behavioral treatments may lead to voice improvement. The purpose of this study was 1) to determine whether vocal fold injection of Cymetra (micronized form of collagen, elastin, proteoglycans; Lifecell Co.) is associated with changes in dysphonic voice characteristics in subjects with IPD, as judged perceptually using a standard instrument Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), and (2) which acoustic and aerodynamic measurements of voice are most reflective of any observed perceptual changes in voice.

STUDY DESIGN

Prospective clinical evaluation of patients with Parkinson's-related dysphonia (PRD).

METHODS

Six patients with PRD were evaluated before treatment for the presence of dysphonia and glottal gap. All subjects underwent transoral vocal fold collagen injection using topical anesthesia in the otolaryngology clinic as part of their clinical care. At the initial clinic visit, and 10 to14 days after vocal fold collagen injection, patients were asked to complete the Voice Handicap Index (VHI), a questionnaire concerning voice-related quality of life, and perceptual analyses of voice quality were performed. In addition, patients underwent acoustic (pitch/loudness range, maximum phonation time [MPT], and aerodynamic phonation threshold pressure [PTP]) voice analysis.

RESULTS

Five of six subjects had self-perceived improvements in voice after treatment, as determined by the VHI (range, +8 to -24). All five subjects who completed testing demonstrated decreased PTP (range, -1.3 to -2.7, P = .002). Five of six subjects demonstrated statistically significant improvements in MPT (range, -2-16 s, P = .05). Five of six subjects had improved pitch range (-26-343 Hz), whereas all subjects had increased intensity range (0.6-23 db) after injection.

CONCLUSIONS

Transoral collagen injection in patients with PRD is safe, well tolerated, and is an effective temporary method of subjectively improving voice and speech in selected patients with IPD. Reduction of glottal gap with collagen improves MPT and subglottal PTP. The resulting gain of vocal efficiency may reduce vocal fatigue and provide a useful adjunct to voice therapy for PRD.

Evaluation and management of laryngopharyngeal reflux

CONTEXT

Laryngopharyngeal reflux (LPR) is a major cause of laryngeal inflammation and presents with a constellation of symptoms different from classic gastroesophageal reflux disease.

OBJECTIVE

To provide a practical approach to evaluating and managing cases of LPR.

EVIDENCE ACQUISITION

The PubMed database and the Ovid Database of Systematic Reviews were systematically searched for laryngopharyngeal reflux, laryngopharyngeal reflux fundoplication, laryngopharyngeal reflux PPI treatment, and gastroesophageal reflux AND laryngitis. Pertinent subject matter journals and reference lists of key research articles were also hand-searched for articles relevant to the analysis.

EVIDENCE SYNTHESIS

Reflux of gastric contents is a major cause of laryngeal pathology. The pathophysiology and symptom complex of LPR differs from gastroesophageal reflux disease. Laryngeal pathology results from small amounts of refluxate--typically occurring while upright during the daytime--causing damage to laryngeal tissues and producing localized symptoms. Unlike classic gastroesophageal reflux, LPR is not usually associated with esophagitis, heartburn, or complaints of regurgitation. There is no pathognomonic symptom or finding, but characteristic symptoms and laryngoscopic findings provide the basis for validated assessment instruments (the Reflux Symptom Index and Reflux Finding Score) useful in initial diagnosis. There are 3 approaches to confirming the diagnosis of LPR: (1) response of symptoms to behavioral and empirical medical treatment, (2) endoscopic observation of mucosal injury, and (3) demonstration of reflux events by impedance and pH-monitoring studies and barium swallow esophagram. While pH monitoring remains the standard for confirming the diagnosis of gastroesophageal reflux, the addition of multichannel intraluminal impedance technology improves diagnostic accuracy for describing LPR events. Ambulatory multichannel intraluminal impedance assessment allows for identification of gaseous as well as liquid refluxate and detection of nonacid reflux events that are likely significant in confirming LPR. Although some patients respond to conservative behavioral and medical management, as is the case with gastroesophageal reflux, most require more aggressive and prolonged treatment to achieve regression of symptoms and laryngeal tissue changes. Surgical intervention such as laparoscopic fundoplication is useful in selected recalcitrant cases with laxity of the gastroesophageal sphincter.

CONCLUSIONS

Laryngopharyngeal reflux should be suspected when the history and laryngoscopy findings are suggestive of the diagnosis. Failure to respond to a 3-month trial of behavioral change and gastric acid suppression by adequate doses of proton pump inhibitor medication dictates need for confirmatory studies. Multichannel intraluminal impedance and pH-monitoring studies are most useful in confirming LPR and assessing the magnitude of the problem.

Therapeutic Potential of Growth Factors for Aging Voice

OBJECTIVES/HYPOTHESIS

It has been reported that in aged vocal folds, dense collagen deposition takes place and hyaluronic acid decreases in the lamina propria, which are thought to contribute to the vocal problems occurring with age (presbyphonia). To restore aged vocal folds to their younger state, it seems crucial to address these age-related lamina propria changes. Intervention that might increase hyaluronic acid and decrease collagen would appear to be a potentially useful approach. The present study examined the effects of growth factors on aged fibroblasts in terms of the production of hyaluronic acid and collagen type I.

STUDY DESIGN

In vitro study using animal model.

METHODS

Fibroblasts were harvested from young and aged rat vocal folds and cultured with or without hepatocyte growth factor and/or basic fibroblast growth factor at different concentrations. Subsequently, the production of hyaluronic acid and collagen type I was examined in the supernatant culture media using enzyme-linked immunosorbent assay.

RESULTS

Aged fibroblasts produced less hyaluronic acid than younger fibroblasts. When aged and young fibroblasts were cultured with basic fibroblast growth factor, hyaluronic acid production increased and collagen type I production decreased regardless of the concentration, whereas the effects of hepatocyte growth factor appeared to vary with concentration. The basic fibroblast growth factor also was associated with stimulation of growth of aged fibroblasts.

CONCLUSION

The present results suggest that growth factors, especially basic fibroblast growth factor, may have therapeutic potential in restoration of aged vocal fold.

Treatment of Vocal Fold Scar with an Auto-Crosslinked Polysaccharide Hyaluronan-Based Gel

Problem: To examine the effectiveness of an auto-crosslinked polysaccharide (ACP) hyaluronan-based gel for the treatment of acute vocal fold scar in a canine animal model.

Methods: Twelve canine larynges were injured by unilateral stripping of the vocal fold mucosa, from the epithelium down to the thyroarytenoid muscle. Six of these animals were treated with a transcutaneous injection of ACP gel (30 mg) into the thyroarytenoid muscle and remaining lamina propria at the time of injury, and again at 7 and 14 days postoperatively. The remaining animals were treated with an injection of sodium chloride to serve as sham controls. All animals were euthanized 2 months following the initial treatment. Excised larynx experiments were completed to obtain phonation threshold pressure (PTP) and vocal economy an acoustic output cost ratio (OCR), followed by histologic analysis for hyaluronan and collagen between the scarred and control vocal fold.

Results: Dense, thick bundle collagen was observed on the injured side of sham-treated larynges. Minimal collagen deposition was observed on the injured side of ACP-treated larynges. PTP was lower and OCR was higher in the ACP-treated animals.

Conclusion: ACP-treated larynges revealed greater ease of phonation and better vocal economy than sham-treated larynges. Collagen deposition was less dense in ACP-treated larynges. ACP gel provided sufficient bulk to the scarred vocal fold.

Significance: ACP gel may provide a useful bio-injectable substance for improving rheologic tissue and aerodynamic properties for phonation in the scarred larynx.

Support: None reported.

Characterization of chronic vocal fold scarring in a rabbit model

The purpose of the current study was to assess the histologic and rheologic properties of the scarred vocal fold lamina propria during a chronic phase of wound repair in a rabbit model. Eighteen rabbit larynges were scarred using a procedure that involved stripping the vocal fold lamina propria down to the thyroarytenoid muscle, using 3-mm microforceps. The approximate dimension of injury to the vocal fold was 3 x 1.5 x 0.5 mm [length x width x depth]. At 6 months postoperatively, histologic analysis of the scarred and control lamina propria in eight of these rabbits was completed for collagen, procollagen, elastin, and hyaluronic acid. Compared with control samples, scarred tissue samples revealed fragmented and disorganized elastin fibers. Additionally, collagen was significantly increased, organized, and formed thick bundles in the scarred vocal fold lamina propria. Measurements of the viscoelastic shear properties of the scarred and control lamina propria in the remaining 10 rabbits revealed increased elastic shear modulus (G') in 8 of 10 scarred samples and increased dynamic viscosity (eta') in 9 of 10 scarred samples. Although rheologic differences were not statistically significant, they revealed that on average, scarred samples were stiffer and more viscous than the normal controls. Histologic data are interpreted as indicating that by 6 months postinjury, the scarred rabbit vocal fold has reached a mature phase of wound repair, characterized by an increased, organized, and thick bundle collagen matrix. Rheologic data are interpreted as providing support for the potential role of increased, thick bundle collagen, and a disorganized elastin network on shear stiffness and dynamic viscosity in the chronic vocal fold scar. Based on these results, a 6-month postoperative time frame is proposed for future studies of chronic vocal fold scarring using the rabbit animal model.

Prevention of Vocal Fold Scarring by Topical Injection of Hepatocyte Growth Factor in a Rabbit Model

OBJECTIVES/HYPOTHESIS

Vocal fold scarring disrupts the layer structure of the vocal fold lamina propria that is essential for optimal mucosal vibration. Prevention of vocal fold scarring remains challenging. Hepatocyte growth factor (HGF) has strong antifibrotic activity. The authors' previous studies have found that HGF stimulates hyaluronic acid production and suppresses collagen production from vocal fold fibroblasts, suggesting that HGF has therapeutic potential in prevention of vocal fold scarring. The present study aimed to demonstrate the effects of HGF on vocal fold scarring in an in vivo rabbit model.

STUDY DESIGN

Animal experiment.

METHODS

The vocal fold mucosa was stripped unilaterally in 20 rabbits, then HGF or saline (sham-treated group) was immediately injected into the injured site. At 6 months after the procedure, histological, rheological, and physiological examinations of vibratory behavior were completed.

RESULTS

Histological examination revealed excessive collagen deposition and disorganized elastin in the sham-treated group, whereas the HGF-treated group presented with better wound healing exhibiting less collagen deposition. Contraction of the injured vocal folds observed in the sham-treated group did not occur in the HGF-treated group. Rheological data indicated that the HGF-treated vocal folds were less stiff and viscous compared with the sham-treated group. Mucosal vibration of HGF-treated vocal folds appeared much better than the sham-treated group in terms of phonation threshold pressure, vocal efficiency, mucosal wave amplitude, and glottal closure.

CONCLUSION

Hepatocyte growth factor proved to be useful in preventing vocal fold scarring and maintaining viscoelastic shear properties of the vocal fold.

Tracking outcomes after phonosurgery for sulcus vocalis: a case report

Outcomes data after a surgical or behavioral intervention should be tracked until stability is reached. Often it is unclear how long patients should be followed and at what point an outcome can be considered stable. These issues have implications for treatment decision making, efficacy measurement, and the design of research studies. Vocal function data were collected 24 hours before and at 1, 6, and 12 months after phonosurgery for sulcus vocalis. One data series was collected daily during the first month after surgery, providing a unique opportunity to study voice changes in the immediate postoperative period. The different vocal function indices (acoustic, perceptual, videostroboscopic, aerodynamic, psychosocial) demonstrated a general pattern of improvement after intervention; however, they appeared to reach stability at different times. This report reinforces the value of following patients until complete outcome stability.

Nonlinear dynamics of phonations in excised larynx experiments

Nonlinear dynamic methods including correlation dimension and Lyapunov exponents are applied to quantitatively analyze phonations in excised larynx experiments. Irregular phonations are typically characterized by aperiodic waveforms and broadband spectra. Finite correlation dimensions and positive Lyapunov exponents of irregular phonations demonstrate the existence of chaos in excised larynx phonations. Furthermore, the correlation dimension, maximal Lyapunov exponent, jitter, shimmer, and peak prominence ratio are used to statistically distinguish irregular phonations from normal phonations. The correlation dimension and maximal Lyapunov exponent indicate a significant difference between irregular and normal phonations; however, jitter, shimmer, and peak prominence ratio do not reveal such a significant difference and thus are unsuitable to differentiate between irregular phonations and normal phonations. These findings might potentially assist investigators in understanding rough phonations and developing clinically valuable methodologies for the diagnosis of voice disorders.

Effect of growth factors on hyaluronan production by canine vocal fold fibroblasts

Hyaluronan (HYA) is considered to be a crucial factor in scarless wound healing and in maintaining tissue viscosity of the vocal fold lamina propria. In this study focusing on the effects of growth factors, we examined how HYA is produced and controlled in canine cultured vocal fold fibroblasts. Fibroblasts were taken from the lamina propria of the vocal folds of 8 dogs and cultured with and without growth factors. The production of HYA in the supernatant culture was quantitatively examined by enzyme-linked immunosorbent assay. Hepatocyte growth factor, epidermal growth factor, basic fibroblast growth factor, and transforming growth factor beta1 all stimulated HYA synthesis from vocal fold fibroblasts. These effects differed with the concentration of growth factors and the incubation period. We also examined how frequently the growth factors had to be administered in order to maintain appropriate levels of HYA. A single administration was sufficient to maintain appropriate HYA levels for at least 7 days. The present studies have demonstrated positive effects of growth factors in stimulating HYA production. Further in vivo study is needed to clarify the usefulness of these growth factors in the management of vocal fold scarring.

Fibronectin and adhesion molecules on canine scarred vocal folds

OBJECTIVE

To examine the expressions of fibronectin and other adhesion molecules on the scarred vocal folds in a short- and long-term animal model.

STUDY DESIGN

Animal model.

METHODS

Six beagles' vocal folds were stripped unilaterally and left untreated. After wounding the vocal folds were harvested from three dogs at 2 months and three dogs at 6 months. The untouched vocal fold was used as a control, and the stripped vocal fold as scarred. Subsequently, the expressions of fibronectin, cadherin, syndecan-1 and syndecan-4 on both vocal folds were examined by immunohistochemical and image analysis.

RESULTS

Compared with the control vocal folds, fibronectin significantly increased in the superficial layer of the lamina propria on the scarred vocal folds at both 2 and 6 months. Co-deposition of collagen was observed only at 6 months. Syndecan-4 was significantly overexpressed at the basal layer cells of the epithelium at both 2 and 6 months. No significant expression of either cadherin or syndecan-1 was detected.

CONCLUSIONS

Scar characteristics at 2 and 6 months are not identical, suggesting that a 2-month period may not be a sufficient to study vocal fold scarring. Adhesion molecules are important in reorganization of extracellular matrix during wound healing because of their binding and adhesion characteristics. The results indicate that fibronectin might be important in providing a scaffold for the deposition of other proteins such as collagen, and the binding characteristics might affect the stiffness of the scarred vocal fold. Prolonged expression of syndecan-4 may reflect the role of focal adhesion during the assembly of scar structure. Ultimately, better understanding of the histological features of the scarred vocal fold might lead to new approaches to treatment.

Age-related alterations in myosin heavy chain isoforms in rat intrinsic laryngeal muscles

Deficits in voice and swallowing are found in the elderly, but the underlying neuromuscular mechanisms are unclear. A potential mechanism may be denervation-induced muscle fiber transformation to a slower-contracting type of muscle fiber. This study examined young, old, and denervated rat laryngeal muscles (lateral thyroarytenoid, lateral cricoarytenoid, and posterior cricoarytenoid) to examine differences in myosin heavy chain (MHC) composition. Results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses indicated that all muscles were composed predominately of type IIB MHC. With aging and denervation, type IIB was reduced and type IIX, a slower-contracting isoform, was increased in the lateral thyroarytenoid and lateral cricoarytenoid muscles. In the posterior cricoarytenoid muscle, the MHC composition was relatively unchanged. These findings suggest that aging may affect laryngeal adductory function by altering muscle fiber type composition to a slower-contracting isoform, in a manner similar to that observed with denervation.

Glottal configuration, acoustic, and aerodynamic changes induced by variation in suture direction in arytenoid adduction procedures

Arytenoid adduction is a phonosurgical procedure in which the arytenoid cartilages are approximated to reduce posterior glottal gap size and improve voice. Voice outcomes following arytenoid adduction are not always optimal. The goal of this study was to systematically vary suture direction and force of pull on the arytenoid cartilages in a human excised laryngeal model to determine the optimal combination of factors for reducing glottal gap and improving voice. Several factors demonstrated significant effects. Changes in suture direction and force of pull affected glottal configuration in both the horizontal and vertical planes. Increased force of pull on the muscular process resulted in increased adduction of the vocal process for all suture directions. Changes in suture direction and force of pull also affected acoustic and aerodynamic measures of induced voice. Therefore, voice outcomes can be optimized with arytenoid adduction if the vocal fold plane is accurately adjusted.

Treatment of vocal fold scarring: rheological and histological measures of homologous collagen matrix

The current treatment options for dysphonia secondary to vocal fold scarring are limited. Few studies address changes in the lamina propria, which is critical to vocal fold biomechanical properties and voice production. Using rheological and histological measures of homologous collagen matrix (HCM)-injected vocal folds, we assessed HCM's potential for providing bulk and restoring biomechanical performance. Twenty rabbits underwent bilateral vocal fold scarring. After 10 weeks of scar maturation, the rabbits had unilateral injections of HCM or saline solution. Ten weeks after the injections, histological studies revealed well-defined collagen globules distributed throughout the lamina propria and underlying muscular tissue. Significantly more procollagen was observed in the HCM-treated group. No significant differences in elastic shear modulus or dynamic viscosity were found between the treatment groups. This study demonstrates that HCM is an inert, relatively stable injectate that may serve well for medialization but does not appear to improve the dynamic properties of the lamina propria.

Laryngeal-respiratory kinematics are impaired in aged rats

Fatigue and weakness in the elderly are the functional consequences of underlying neuromuscular decline. However, little is known about the manifestations of aging in the larynx. This study evaluated the manner in which laryngeal senescence affects laryngeal-respiratory kinematics by videorecording laryngeal motion in both young and old rats. Recorded images were digitized, and glottal displacement and movement rate were measured. The results indicated that the amplitude of change in glottal angle was significantly diminished, and laryngeal movement durations were prolonged in the old animals. These findings may be due to functional constraints on the respiratory system, impaired laryngeal-respiratory interactions, or decrements in vocal fold tension with age. Because of the serious and pervasive nature of dysphagia and communicative impairments in the elderly, research that specifically examines the manifestations and causes of these impairments is of great importance.

Hepatocyte growth factor and its receptor c-met in rat and rabbit vocal folds

Vocal fold fibrotic scar is characterized by fibrosis of the lamina propria and epithelium, and is difficult to treat. Hepatocyte growth factor (HGF) has antifibrotic activity and has received attention as a possible therapeutic alternative to treat fibrosis. In this study, in order to clarify whether HGF can be involved in vocal fold scarring, we examined the existence of HGF and its receptor, c-Met, in rat vocal folds, and then the activity of HGF in rabbit injured vocal folds, using immunohistochemistry and enzyme-linked immunosorbent assay. We found HGF and c-Met on epithelial cells and gland cells of the rat vocal folds. On the injured vocal folds of rabbits, little HGF was observed immediately after injury, but prominent activity occurred simultaneously with reepithelialization of the vocal fold mucosa on days 10 to 15. The activity of HGF was observed on fibroblasts in the lamina propria, as well as the epithelium. It is suggested that HGF in the vocal folds is produced by the fibroblasts and delivered to the epithelium. The implication of these findings is that HGF is involved in wound healing of the vocal fold, and may provide an alternative approach in preventing and treating vocal fold scarring.

Genotypic and phenotypic expression of vocal fold polyps and Reinke's edema: a preliminary study

Although a great deal of research exists regarding lamina propria composition, no report exists that relates gene expression in benign laryngeal lesions to phenotypic markers. In this study, messenger RNA profiles for extracellular matrix proteins--procollagen I, collagenase, elastase, fibronectin, fibromodulin, decorin, hyaluronic acid synthase 2, and hyaluronidase--were completed on 5 polyps and 4 Reinke's edema specimens. These genotypic profiles were correlated to a videostroboscopic parameter of mucosal wave stiffness, which was used as a measurement of phenotypic expression. Polyps, characterized by stiffer mucosal waves, had higher levels of gene expression, whereas stiffer mucosal wave scores for Reinke's edema were associated with lower gene activity levels. This study supports the hypothesis that there is a relationship between genotypic expression found in polyps and Reinke's edema and phenotype as defined by a loss of or a decreased mucosal wave. The study also gives clues as to the proteins responsible for the phenotype.

Histologic and rheologic characterization of vocal fold scarring

Scarring of the vocal fold causes considerable dysphonia and presents significant treatment challenges. A rabbit model was developed to investigate the histologic ultrastructure and rheologic properties of the scarred vocal fold lamina propria. Eleven rabbit larynges were scarred by means of forcep biopsy. Sixty days postoperatively, the rabbits were sacrificed and their vocal folds were harvested. Histological analysis of the scarred and normal lamina propria was completed for collagen, procollagen, elastin, and hyaluronic acid. Linear viscoelastic shear properties of the tissues were also measured, including elastic shear modulus and dynamic viscosity. Compared to normal vocal fold lamina propria, scarred tissues demonstrated significantly less collagen, an increase in procollagen, and a decrease in elastin. Rheologically, both elastic shear modulus and dynamic viscosity were significantly higher for the scarred tissues. Increased stiffness and viscosity do not appear to result from an increase in collagen, but rather appear to be related to the presence of new, disorganized collagen scaffolding. Results are interpreted in terms of the possible role of interstitial proteins in the etiology of increased stiffness and viscosity, which requires further investigation. This animal model should allow for systematic future investigations of vocal fold scarring and its treatment.

Resistance to botulinum toxin injections for spasmodic dysphonia

A known complication of botulinum toxin injections in the treatment of dystonia has been the occasional development of resistance. This has been seen primarily with patients who receive injections for torticollis. We report on 2 patients who, after several years of receiving injections for spasmodic dysphonia, developed clinical resistance by failing to have expected voice improvement after receiving laryngeal reinjection. One of the 2 patients demonstrated antibodies to botulinum toxin by mouse neutralization bioassay. The second patient had negative bioassay results but had no clinical response to the test toxin injection of facial muscles. These cases demonstrate that, although uncommon, resistance to botulinum toxin injections can occur in the treatment of spasmodic dysphonia. We offer suggestions to limit this complication.

Advances and refinements in phonosurgery

Scientific discovery, technological advances, and improved outcomes assessment have resulted in advances and refinements in phonosurgery. Three areas of substantial evolution are phonomicrosurgery, laryngeal framework surgery, and the use of implantable materials in vocal folds. Discovery of the importance of the superficial layers of the lamina propria has led to increased use of more limited medial microflap approaches and less frequent use of the classic lateral cordotomy flap approach. Alternative approaches to managing vocal fold scarring defects have addressed the separation of body and cover and provided suitable lamina propria replacement. Approaches to sulcus vocalis have been refined to address type II (linear vergeture) and type III (focal invasive pit) sulcus, where there is loss of lamina propria, while still recognizing the common nonpathological type I (physiological) sulcus. Technological advancements such as photodynamic therapy, tuned dye lasers, and laryngeal microdebridement have augmented the armamentarium for mechanical removal of laryngeal papillomata. Careful infusion-assisted microexcision and adjunctive medical management have been refined and made more effective. Laryngeal framework surgery has embraced the development of Silastic, hydroxylapatite, expanded polytetrafluoroethylene, and titanium shims. Anatomical studies have helped to improve operative precision and safety, and have led to inventive variations in arytenoid repositioning that improve closure of the posterior subunit. Vocal fold augmentation by injection has been facilitated by innovative use of the rigid telescope and intraoperative videostroboscopy. Anatomical studies have focused on the infrafold region and rheological studies have attempted to match viscoelastic properties of injectable substances to those of vocal fold tissues. Alloplastic materials such as Teflon have been largely supplanted by newer bioimplantables such as fat, collagen, and fascia.

Muscle fiber-type changes induced by botulinum toxin injection in the rat larynx

This study examined muscle fiber-type alterations after single or multiple botulinum toxin (BT) injections to better understand possible morphologic changes induced by therapeutic BT injections in patients with spasmodic dysphonia. Muscle fiber staining was accomplished in rat intrinsic laryngeal muscles with antibodies to specific myosin heavy chains. Results indicated that the typical baseline distributions of type II muscle fibers (ie, types IIa, IIb, IIx, and IIL) were altered by BT injection, while no change was observed in type I fibers. Embryonic fibers were observed only along the needle insertion site at 7 days post BT injection. Although inferences from these animal data to human neuromuscular function must be made with caution, our findings provide insight into the possible cellular and molecular changes characterizing BT-injected muscles.

Influence of computed tomography on pretherapeutic tumor staging in head and neck cancer patients

Refinements in radiographic techniques have resulted in increased use of radiographic studies in the evaluation of patients with head and neck cancer over the past 20 years. To assess the impact of such studies, we compared tumor clinical stages based solely on physical-examination findings with those obtained with the addition of CT findings. This study was accomplished through case review of 81 head and neck cancer patients who underwent CT after preliminary TNM-stage assignment as determined on the basis of physical examination alone. In this cohort, 44 patients (54%) had a change in assigned clinical stage. We reviewed individual anatomic sites to determine where CT was found to be most useful in modifying tumor stage. Changes in tumor and nodal stage were found across all major sites of the head and neck. Tumors of the hypopharynx were the most likely to change stage (90%) on the basis of CT findings, whereas tumors of the glottic larynx were least likely to undergo a change in stage (16%). The therapeutic implications of these findings are discussed in the context of the published literature.