Allograft (Alloderm) and Autograft (Temporalis Fascia) Implantation for Glottic Insufficiency: A Novel Approach

Objective

Traditionally, glottic insufficiency because of scar, atrophy, and sulcus has been treated by injection or medialization laryngoplasty. These procedures do not reestablish the vertical height of the vocal fold margin. We propose soft tissue augmentation laryngoplasty with allograft (sheet Alloderm; LifeCell Corporation, Branchburg, NJ) or autograft (temporalis fascia) via a minithyrotomy or a transoral approach.

Study Design

A retrospective case series analysis of 21 patients treated by sheet Alloderm or temporalis fascia for correction of glottic insufficiency.

Methods

Twenty-one patients with glottic insufficiency secondary to scar, atrophy, or sulcus were treated. Ten failed prior techniques. Seventeen had minithyrotomy by a small fenestration in the thyroid cartilage. Exploration of scar or lamina propria through the fenestration allowed for the creation of a pocket for Alloderm implantation within the intermediate layer of the lamina propria. Four patients underwent a transoral approach by cordotomy with either Alloderm or temporalis fascia implantation, which also allowed for exploration of scar but required repair using sutures. These implantation approaches allowed for both restoration of the layered structure and augmentation of the middle third of the musculomembranous vocal fold. Preoperative and postoperative videostroboscopic examinations were reviewed with review of clinical outcome.

Results

With a median follow-up time of 12 months, patients demonstrated excellent long-term vocal fold augmentation and minimal absorption of the implant in 19 out of 21 patients. There is improved pliability of the vocal fold with good oscillation in scar patients.

Conclusion

Minithyrotomy with soft tissue augmentation is a novel approach for soft tissue augmentation of glottic insufficiency. It has the advantage of augmentation of the medial edge of the vocal fold with a soft tissue implant that has long-term viability. Its role should be explored further in patients with atrophy and scar.     

Vocal Tract Configurations in Male Alto Register Functions

Purpose

Professional male altos (countertenors) mostly use a register function, which is considered to be derived from falsetto. However, the sound produced differs in professional altos compared with the modal register or falsetto of untrained voices. The aim of this study was to analyze differences of the vocal tract shapes in male alto register functions.

Material and Methods

Dynamic real-time magnetic resonance imaging of eight frames per second was used to analyze the vocal tract profile in seven professional male altos who sang on the vowel /a/, an ascending and descending scale from G3 (196 Hz) to E4 (330 Hz). The scale included their register transition from modal register to stage (counter) falsetto and naïve falsetto.

Results

Register transitions from modal register to stage falsetto were associated with increased lip opening, jaw retraction, elevation and back positioning of the tongue, pharynx narrowing, uvula elevation, drop of larynx height, and tilting of the larynx. Differences between stage and naïve falsetto were found mostly with regard to lip opening and pharynx width.

Conclusions

The differences between the vocal tract configurations might have an impact on the acoustic characteristics observed in professional male alto register functions.     

MRI Anatomical and Morphological Differences in the Vocal Tract Between Dysphonic and Normal Adult Women

Objective

To analyze the vocal tract morphometry of women with vocal nodules (VN) compared with normal subjects by means of magnetic resonance imaging (MRI) at rest position.

Study Design

Prospective study.

Methods

The present research included 20 young adult women, aged 18–40 years: 10 dysphonic patients with VN and 10 normal subjects. All participants were tested using MRI; 12 measurements of the vocal tract were performed: nine in median sagittal section and three in axial section.

Results

The 12 measurements were smaller in the dysphonic group; statistical significance was obtained for three parameters: in the sagittal plane, the laryngeal vestibule area was significantly smaller in the dysphonic group, with P = 0.012∗ (∗ = statistical significance); in the axial section, the distance between the right and left vocal processes of the arytenoids’ cartilages and the distance between the anterior commissure of the glottis and the laryngeal posterior wall were also significantly lower in the dysphonic group, with P = 0.036∗ and 0.010∗, respectively. Significant differences in the vocal tract morphometry of individuals with VN were observed compared with normal subjects, at rest position.

Conclusions

Results obtained from this study suggest that patients with VN may present a constantly increased tension of the laryngeal muscles, even at rest; moreover, reduced anterior-posterior dimension of the larynx may be a morphological characteristic of patients with VN.     

Bacterial Cellulose as Laryngeal Medialization Material: An Experimental Study

Hypothesis

The use of a material made of bacterial cellulose with the aim of obtaining vocal fold medialization has not hitherto been fully investigated. Although the material has been tested in other animal models, the evaluation did not include the larynx; hence, situations, such as tissue reaction, material absorption, and extrusion, need to be addressed to evaluate its usefulness as a material for laryngeal reconstruction.

Objective

To evaluate the medialization, tissue response, and healing of rabbit vocal folds, after the implantation of a membrane of bacterial cellulose.

Study Design

Experimental study.

Methods

A total of 32 rabbits were used, two of which were used to check out the adequacy of the implant location. The animals were followed for 4 months and grouped according to follow-up times of 2, 4, and 16 weeks. All test animals received an implant of bacterial cellulose in one vocal fold and the injection of distilled water in the other, both performed by videoendoscopic cervicotomy. At the end of the follow-up, the presence of inflammatory and medial displacement was evaluated.

Results

No statistically significant difference in the inflammatory parameters between the study and control vocal folds or among follow-up times was found. All animals receiving cellulose presented medial displacement of vocal folds, and all retained this material at the implant site up to study endpoint.

Conclusion

Bacterial cellulose is a useful material for laryngeal medialization, showing no signs of rejection or absorption.     

Diffusion-weighted echo-planar imaging of the head and neck using 3-T MRI: Investigation into the usefulness of liquid perfluorocarbon pads and choice of optimal fat suppression method

Purpose

To investigate whether image quality can be improved using liquid perfluorocarbon pads (Sat Pad) and clarify the optimal fat-suppression method among chemical shift selective (CHESS), water excitation (WEX), and short TI inversion recovery (STIR) methods in diffusion-weighted imaging (DWI) of the head and neck using 3-T magnetic resonance imaging. Correlations between results of visual inspection and quantitative analysis were also examined.

Material and Methods

This study was approved by our Institutional Review Board and informed consent was waived. DWI was performed on 25 subjects with/without Sat Pad and using three fat-suppression methods (6 patterns). Image quality was evaluated visually (4-point scales and lesion-depiction capability) and by quantitative analysis (signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)). Two-way repeated-measures analysis of variance (ANOVA) was used to detect significant differences in scores of visual evaluation, SNR, and CNR.

Results

Mean visual evaluation scores were significantly higher with Sat Pad using STIR than without Sat Pad for all fat-suppression methods (P < 0.05). DWI with Sat Pad using STIR tended to be useful for depicting lesions. DWI using STIR showed reduced W-SNR (W: whole area of depicted structure) and CNR (between semispinalis capitis muscle and subcutaneous fat) due to fewer artifacts and uniform fat suppression.

Conclusion

Combining Sat Pad with STIR provides good image quality for visual inspections. When numerous artifacts are present and fat suppression is insufficient, higher SNR and CNR do not always provide good diagnostic image quality.     

Dynamic magnetic resonance imaging of swallowing and laryngeal motion using parallel imaging at 3 T

Object

To evaluate the feasibility of an optimized MRI protocol based on high field imaging at 3 T in combination with accelerated data acquisition by parallel imaging for the analysis of oropharyngeal and laryngeal function.

Materials and Methods

Fast 2D gradient echo (GRE) MRI with different spatial resolutions (1.7×2.7 and 1.1×1.5 mm²) and image update rates (4 and 10 frames per second) was employed to assess pharyngeal movements and visualize swallowing via tracking of an oral contrast bolus (blueberry juice). In a study with 10 normal volunteers, image quality was semi-quantitatively graded by three independent observers with respect to the delineation of anatomical detail and depiction of oropharynx and larynx function. Additionally, the feasibility of the technique for the visualization of pathological pre- and post-surgical oropharynx and larynx function was evaluated in a patient with inspiratory stridor.

Results

Image grading demonstrated the feasibility of dynamic MRI for the assessment of normal oropharynx and larynx anatomy and function. Superior image quality (P<.05) was found for data acquisition with four frames per second and higher spatial resolution. In the patient, dynamic MRI detected pathological hypermobility of the epiglottis resulting in airway obstruction. Additional post-surgical MRI for one clinical case revealed morphological changes of the epiglottis and improved function, i.e., absence of airway obstruction and normal swallowing.

Conclusion

Results of the volunteer study demonstrated the feasibility of dynamic MRI at 3 T for the visualization of the oropharynx and larynx function during breathing, movements of the tongue and swallowing. Future studies are necessary to evaluate its clinical value compared to existing modalities based on endoscopy or radiographic techniques.     

Expression of ionotropic glutamate receptors in the retina of the rdta transgenic mouse

Background

One mechanism that directs the action of the second messengers, cAMP and diacylglycerol, is the compartmentalization of protein kinase A (PKA) and protein kinase C (PKC). A-kinase anchoring proteins (AKAPs) can recruit both enzymes to specific subcellular locations via interactions with the various isoforms of each family of kinases. We found previously that a new class of AKAPs, dual-specific AKAPs, denoted D-AKAP1 and D-AKAP2, bind to RIα in addition to the RII subunits.

Results

Immunohistochemistry and confocal microscopy were used here to determine that D-AKAP1 colocalizes with RIα at the postsynaptic membrane of the vertebrate neuromuscular junction (NMJ) and the adjacent muscle, but not in the presynaptic region. The labeling pattern for RIα and D-AKAP1 overlapped with mitochondrial staining in the muscle fibers, consistent with our previous work showing D-AKAP1 association with mitochondria in cultured cells. The immunoreactivity of D-AKAP2 was distinct from that of D-AKAP1. We also report here that even though the PKA type II subunits (RIIα and RIIβ) are localized at the NMJ, their patterns are distinctive and differ from the other R and D-AKAP patterns examined. PKCβ appeared to colocalize with the AKAP, gravin, at the postsynaptic membrane.

Conclusions

The kinases and AKAPs investigated have distinct patterns of colocalization, which suggest a complex arrangement of signaling micro-environments. Because the labeling patterns for RIα and D-AKAP 1 are similar in the muscle fibers and at the postsynaptic membrane, it may be that this AKAP anchors RIα in these regions. Likewise, gravin may be an anchor of PKCβ at the NMJ.     

Mathematical modelling and numerical simulation of the morphological development of neurons

Background

The morphological development of neurons is a very complex process involving both genetic and environmental components. Mathematical modelling and numerical simulation are valuable tools in helping us unravel particular aspects of how individual neurons grow their characteristic morphologies and eventually form appropriate networks with each other.

Methods

A variety of mathematical models that consider (1) neurite initiation (2) neurite elongation (3) axon pathfinding, and (4) neurite branching and dendritic shape formation are reviewed. The different mathematical techniques employed are also described.

Results

Some comparison of modelling results with experimental data is made. A critique of different modelling techniques is given, leading to a proposal for a unified modelling environment for models of neuronal development.

Conclusion

A unified mathematical and numerical simulation framework should lead to an expansion of work on models of neuronal development, as has occurred with compartmental models of neuronal electrical activity.

     

The temporal relationship between reduction of early imitative responses and the development of attention mechanisms

Background

To determine whether early imitative responses fade out following the maturation of attentional mechanisms, the relationship between primitive imitation behaviors and the development of attention was examined in 4-month-old infants. They were divided into high and low imitators, based on an index of imitation. The status of attention was assessed by studying inhibition of return (IOR). Nine-month-old infants were also tested to confirm the hypothesis.

Results

The IOR latency data replicate previous results that infants get faster to produce a covert shift of attention with increasing age. However, those 4-month-olds who showed less imitation had more rapid saccades to the cue before target presentation.

Conclusion

The cortical control of saccade planning appears to be related to an apparent drop in early imitation. We interpret the results as suggesting a relationship between the status of imitation and the neural development of attention-related eye movement.

     

2-NBDG Fluorescence Imaging of Hypermetabolic Circulating Tumor Cells in Mouse Xenograft model of Breast Cancer

Objectives

To determine use of 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG) as a tracer for detection of hypermetabolic circulating tumor cells (CTC) by fluorescence imaging.

Procedures

Human breast cancer cells were implanted in the mammary gland fat pad of athymic mice to establish orthotopic human breast cancer xenografts as a mouse model of circulating breast cancer cells. Near-infrared fluorescence imaging of the tumor-bearing mice injected with 2-DeoxyGlucosone 750 (2-DG 750) was conducted to assess glucose metabolism of xenograft tumors. Following incubation with fluorescent 2-NBDG, circulating breast cancer cells in the blood samples collected from the tumor-bearing mice were collected by magnetic separation, followed by fluorescence imaging for 2-NBDG uptake by circulating breast cancer cells, and correlation of the number of hypermetabolic circulating breast cancer cells with tumor size at the time when the blood samples were collected.

Results

Human breast cancer xenograft tumors derived from MDA-MB-231, BT474, or SKBR-3 cells were visualized on near-infrared fluorescence imaging of the tumor-bearing mice injected with 2-DG 750. Hypermetabolic circulating breast cancer cells with increased uptake of fluorescent 2-NBDG were detected in the blood samples from tumor-bearing mice and visualized by fluorescence imaging, but not in the blood samples from normal control mice. The number of hypermetabolic circulating breast cancer cells increased along with growth of xenograft tumors, with the number of hypermetabolic circulating breast cancer cells detected in the mice bearing MDA-MB231 xenografts larger than those in the mice bearing BT474 or SKBR-3 xenograft tumors.

Conclusions

Circulating breast cancer cells with increased uptake of fluorescent 2-NBDG were detected in mice bearing human breast cancer xenograft tumors by fluorescence imaging, suggesting clinical use of 2-NBDG as a tracer for fluorescence imaging of hypermetabolic circulating breast cancer cells.     

Investigating the Effects of Caffeine on Phonation

Objective

A core component of vocal hygiene programs is the avoidance of agents that may dry the vocal folds. Clinicians commonly recommend that individuals reduce caffeine intake because of its presumed dehydrating effects on the voice. However, there is little evidence that ingestion of caffeine is detrimental to voice production. The first objective of this study was to evaluate whether caffeine adversely affects voice production. The second objective was to evaluate if caffeine exacerbates the adverse phonatory effects of vocal loading.

Study Design

Prospective, double-blinded, sham-controlled study.

Methods

Sixteen healthy adults participated in two sessions where they consumed caffeine (caffeine concentration = 480 mg) or sham (caffeine concentration = 24 mg) beverages. Voice measures (phonation threshold pressure and perceived phonatory effort) were collected. Subjects then completed a vocal loading challenge and voice measures were obtained again.

Results

There were no significant differences in voice measures between the caffeine and sham conditions. Ingestion of caffeine did not adversely affect voice production (P > 0.05) or exacerbate the detrimental phonatory effects of vocal loading (P > 0.05).

Conclusions

Our findings contribute to emerging knowledge on the effects of caffeine on voice production. Recommendations to completely eliminate caffeine from the diet, as a component of a vocal hygiene program, should be evaluated on an individual basis.     

Relationship between central and peripheral corneal astigmatism in elderly patients

Purpose

We investigated the relationship between central and peripheral corneal astigmatism in elderly patients.

Methods

Seventy-six eyes of 76 elderly subjects (mean age?=?72.6?±?3.0 years) were included in the study. Corneal shape was evaluated using the Pentacam HR (Oculus, Wetzlark, Germany), which is comprised of a rotating Scheimpflug camera and a short-wavelength slit light. The power distribution map was selected and corneal astigmatism was calculated using front K-Readings in zones centered on the pupil. Analyzed zones were 2.0–6.0 mm in diameter.

Results

Corneal astigmatism decreased as diameter increased, similar to what was observed in eyes with with-the-rule astigmatism and against-the-rule astigmatism (ANOVA, p?<?0.01). This effect was more pronounced in eyes with a large central corneal astigmatism (Spearman’s rank-correlation coefficient test, r?=?0.51, p?<?0.01). There was no change as to axis of corneal astigmatism (ANOVA, p?=?0.98).

Conclusion

These results suggest that the relationship between central and peripheral corneal astigmatism should be taken into consideration to optimize vision when astigmatic correction is needed.

     

Levels of Evidence in the Voice Literature

Objective

The purpose of this study was to evaluate the levels of evidence in the voice literature.

Study Design

Retrospective literature review.

Methods

Retrospective review of all original articles published between January 2004 and December 2009 from four general otolaryngology journals and one subspecialty voice journal. All abstracts related to voice were evaluated and rated as to evidence-based medicine rating, graded levels A–D and 1a–5. Articles were also stratified by time over two consecutive 3-year intervals to assess changes over the time period.

Results

Of the 6052 articles published, 950 (15.6%) were related to voice. Six hundred seventy-three articles (10.2%) were clinical articles, and 277 (4.6%) were basic science. Only 1% of the clinical articles were level A, 17% were level B, 73% were level C, and 9% were level D. No noticeable changes occurred in the levels of evidence over the interval of the first 3 years of the study in comparison to the last 3 years, although there was an increase in the number of basic science articles from 24.4% to 32.4%.

Conclusion

Despite strong recent interest in improving the quality of the evidence in the literature, the voice literature remains primarily level C and D with no appreciable change over the past 6 years.     

Mapping of neurokinin-like immunoreactivity in the human brainstem

Background

Using an indirect immunoperoxidase technique, we have studied the distribution of immunoreactive fibers and cell bodies containing neurokinin in the adult human brainstem with no prior history of neurological or psychiatric disease.

Results

Clusters of immunoreactive cell bodies and high densities of neurokinin-immunoreactive fibers were located in the periaqueductal gray, the dorsal motor nucleus of the vagus and in the reticular formation of the medulla, pons and mesencephalon. Moreover, immunoreactive cell bodies were found in the inferior colliculus, the raphe obscurus, the nucleus prepositus hypoglossi, and in the midline of the anterior medulla oblongata. In general, immunoreactive fibers containing neurokinin were observed throughout the whole brainstem. In addition to the nuclei mentioned above, the highest densities of such immunoreactive fibers were located in the spinal trigeminal nucleus, the lateral reticular nucleus, the nucleus of the solitary tract, the superior colliculus, the substantia nigra, the nucleus ambiguus, the gracile nucleus, the cuneate nucleus, the motor hypoglossal nucleus, the medial and superior vestibular nuclei, the nucleus prepositus hypoglossi and the interpeduncular nucleus.

Conclusion

The widespread distribution of immunoreactive structures containing neurokinin in the human brainstem indicates that neurokinin might be involved in several physiological mechanisms, acting as a neurotransmitter and/or neuromodulator.     

On the matching of top-down knowledge with sensory input in the perception of ambiguous speech

Background

How does the brain repair obliterated speech and cope with acoustically ambivalent situations? A widely discussed possibility is to use top-down information for solving the ambiguity problem. In the case of speech, this may lead to a match of bottom-up sensory input with lexical expectations resulting in resonant states which are reflected in the induced gamma-band activity (GBA).

Methods

In the present EEG study, we compared the subject's pre-attentive GBA responses to obliterated speech segments presented after a series of correct words. The words were a minimal pair in German and differed with respect to the degree of specificity of segmental phonological information.

Results

The induced GBA was larger when the expected lexical information was phonologically fully specified compared to the underspecified condition. Thus, the degree of specificity of phonological information in the mental lexicon correlates with the intensity of the matching process of bottom-up sensory input with lexical information.

Conclusions

These results together with those of a behavioural control experiment support the notion of multi-level mechanisms involved in the repair of deficient speech. The delineated alignment of pre-existing knowledge with sensory input is in accordance with recent ideas about the role of internal forward models in speech perception.

     

Validation of an adapted MRI pulse sequence for quantification of fatty infiltration in muscle

Purpose

The long-term goal of our research is to develop a patient-specific biomechanical model of the supraspinatus muscle and tendon for analyzing the effects of fatty infiltration and pennation angle changes. One input of the model will be the amount and distribution of fat within the muscle. Therefore, the objective of this project was to adapt and validate a novel magnetic resonance imaging pulse sequence for quantifying the extent of fatty infiltration for the supraspinatus muscle.

Methods

Samples of incremental combinations of muscle and fat from a cow were prepared and scanned with our quantitative MR technique. The MR results were compared to actual fat measurements taken using a Soxtec extraction analyzer.

Results

The MR fat quantification results closely match those values determined by Soxtec analysis (R²=.98, root mean square deviation=4.9).

Conclusions

Our MR fat quantification protocol can be used to accurately quantify fatty infiltration in skeletal muscle. This ability to evaluate skeletal muscle tissue noninvasively will improve the efficacy of evaluation of fatty degeneration in assessing tissue quality preoperatively. This can be important in surgical planning of any musculoskeletal repairs, particularly rotator cuff tears.