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IntroductionAlthough phonatory glottal posture and airflow pulse shape affect voice quality, studies to date have been limited by visualization of vocal fold (VF) vibration from a superior view. We performed a 3D reconstruction of VF vibratory motion during phonation from a medial view and assessed the glottal volume waveform and resulting acoustics as a function of neuromuscular stimulation.Study designIn vivo canine hemilarynx phonation.MethodsAcross 121 unique combinations of the superior laryngeal nerve (SLN) and recurrent laryngeal nerve (RLN) stimulation, the hemilarynx was excited to the oscillation with airflow. VF medial surface reference points were tracked on high-speed video, mapped into 3D space, and surface shape was restored using cubic spline interpolation. Glottal surface shape, reconstruction-based parameters, and glottal volume waveform were calculated. Fundamental frequency (F0), cepstral peak prominence (CPP), and harmonic amplitude (H1-H2) were measured from high-quality audio samples.ResultsThe glottis was convergent during opening and divergent during closing. Neuromuscular activation changed phonatory glottal shape and reduced glottal volume. Significant reduction in glottal volume and closing quotient were present with SLN stimulation. RLN stimulation significantly increased F0 and CPP and decreased H1-H2 (constricted glottis), while SLN effects were similar and synergistic with concurrent RLN stimulation.Conclusion3D reconstruction of in vivo medial surface vibration revealed effects of laryngeal nerve stimulation on glottal vibratory pattern and acoustic correlates of voice quality. SLN activation resulted in significantly quicker glottal closure per cycle, decreased glottal volume, and higher-pitched, less breathy, and less noisy voice. RLN had a similar effect on acoustic measures.Level of evidenceNA, Basic Science Laryngoscope, 133:357-365, 2023.

Objectives/hypothesisPsychosocial distress is common among patients with head and neck cancer (HNC) and is associated with poorer quality of life and clinical outcomes. Despite these risks, distress screening is not widely implemented in HNC care. In this study, we investigated the prevalence of psychosocial distress and its related factors in routine care of patients with HNC.MethodsData from medical records between September 2017 and March 2020 were analyzed. Psychosocial distress was measured by the National Comprehensive Cancer Network's Distress Thermometer (DT), and a modified HNC-specific problem list; depression and anxiety were assessed using the Patient Health Questionnaire-4. Descriptive statistics and logistic regression were conducted to report prevalence of distress, depression and anxiety, and factors associated with clinical distress. Implementation outcomes, including rates of referrals and follow-up for distressed patients, are also reported.ResultsTwo hundred and eighty seven HNC patients completed the questionnaire (age 64.3 ± 14.9 years), with a mean distress score of 4.51 ± 3.35. Of those, 57% (n = 163) reported clinical distress (DT ≥ 4). Pain (odds ratio [OR] = 3.31, 95% CI = 1.75-6.26), fatigue (OR = 2.43, 95% CI = 1.1.7-5.05), anxiety (OR = 1.63, 95% CI = 1.30-2.05), and depression (OR = 1.51, 95% CI = 1.04-2.18) were significantly associated with clinical distress (P

IntroductionVibratory asymmetry and neuromuscular compensation are often seen in laryngeal neuromuscular pathology. However, the ramifications of these findings on voice quality are unclear. This study investigated the effects of varying levels of vibratory asymmetry and neuromuscular compensation on cepstral peak prominence (CPP), an analog of voice quality.Study designIn vivo canine phonation model.MethodsVarying degrees of vocal fold vibratory asymmetry were achieved by stimulating one recurrent laryngeal nerve (RLN) over 11 levels from threshold to maximal muscle activation. For each of these levels, phonation was induced at systematically varied combinations of neuromuscular compensation: three levels each of contralateral RLN stimulation (80%, 90%, and 100% of maximal), superior laryngeal nerve (SLN) activation (0%, 50%, and 100% of maximal), and airflow levels (500, 700, and 900 mL/s). Vocal fold symmetry was determined by assessing the opening phase of the vibratory cycle in high-speed video recordings. Voice quality was estimated acoustically by calculating CPP for each voice sample.ResultsEight hundred twenty-two phonatory conditions with varying degrees of vibratory asymmetry were evaluated. CPP was highest at vibratory symmetry. Increasing levels of asymmetry resulted in significant decreases in CPP. CPP increased significantly with increasing contralateral RLN activation. CPP was significantly higher at 50% SLN activation than 0% or 100% SLN activation.ConclusionVoice quality, as approximated by CPP, is best at vibratory symmetry and deteriorates with increasing degrees of asymmetry. Voice quality may be improved with neuromuscular compensation by increased adduction of the contralateral vocal fold or increased vocal fold tension at mid-levels of SLN activation.Level of evidenceNA, Basic Science Laryngoscope, 132:130-134, 2022.

ObjectivesLaryngeal vibratory asymmetry occurring with paresis may result in a perceptually normal or abnormal voice. The present study aims to determine the relationships between the degree of vibratory asymmetry, acoustic measures, and perception of sound stimuli.Study designAnimal Model of Voice Production, Perceptual Analysis of Voice.MethodsIn an in vivo canine model of phonation, symmetric and asymmetric laryngeal vibration were obtained via graded unilateral recurrent laryngeal nerve (RLN) stimulation simulating near paralysis to full activation. Phonation was performed at various contralateral RLN and bilateral superior laryngeal nerve stimulation levels. Naïve listeners rated the perceptual quality of 182 unique phonatory samples using a visual sort-and-rate task. Cepstral peak prominence (CPP) was calculated for each phonatory condition. The relationships among vibratory symmetry, CPP, and perceptual ratings were evaluated.ResultsA significant relationship emerged between RLN stimulation and perceptual rating, such that sound samples from low RLN levels were preferred to those from high RLN levels. When symmetric vibration was achieved at mid-RLN stimulation, listeners preferred samples from symmetric vibration over those from asymmetric vibration. However, when symmetry was achieved at high RLN levels, a strained voice quality resulted that listeners dispreferred over asymmetric conditions at lower RLN levels. CPP did not have a linear relationship with perceptual ratings.ConclusionsLaryngeal vibratory asymmetry produces variable perceptual differences in phonatory sound quality. Though CPP has been correlated with dysphonia in previous research, its complex relationship with quality limits its usefulness as clinical marker of voice quality perception.Level of evidenceNA, basic science Laryngoscope, 131:2740-2746, 2021.

Objectives/hypothesisArytenoid adduction (AA) is performed to treat unilateral vocal fold paralysis with a large posterior glottal gap. However, the voice effects of AA suture position remain unclear. This study aimed to evaluate voice production and quality as a function of AA suture position on the thyroid ala in a neuromuscularly intact in vivo larynx.Study designAnimal model.MethodsUnilateral recurrent laryngeal nerve and vagal paralysis were modeled in two canines. AA suture position was varied across five equidistant positions on the anterior inferior thyroid ala, from a paramedian position anteriorly to the oblique line posteriorly. Phonation was performed over 8 × 8 graded level combinations of recurrent and superior laryngeal nerve stimulation per suture position. The primary outcome was percent successful phonatory conditions. Secondary outcomes included fundamental frequency (F0), phonation onset pressure (PTP), cepstral peak prominence (CPP), and laryngeal posture.ResultsAnterior suture positions resulted in a greater percentage of successful phonatory conditions compared to posterior sutures. Suture position 2, located at the anterior inferior thyroid ala, resulted in the highest percentage of successful phonatory conditions, lowest PTP, and lower muscle activation levels to achieve higher CPP. Posterior sutures resulted in wider glottal gap and more effective F0 and vocal fold strain increase with cricothyroid muscle contraction, but with fewer successful phonatory conditions and higher PTP. Trends were consistent across both paralysis types.ConclusionsAA suture placed in the anterior inferior thyroid ala resulted in the best acoustic, aerodynamic, and voice quality outcomes. This study provides scientific evidence for maintaining current clinical practice.Level of evidenceNA Laryngoscope, 131:846-852, 2021.

Objectives/hypothesisTo assess the safety and efficacy of autologous cultured fibroblasts (ACFs) to treat dysphonia related to vocal fold scar and age-related vocal atrophy (ARVA).Study designRandomized, double-blinded, placebo-controlled, multi-institutional, phase II trial.MethodsACFs were expanded from punch biopsies of the postauricular skin in each subject; randomization was 2:1 (treatment vs. placebo). Three injections of 1-2 × 107 cells or placebo saline was performed at 4-week intervals for each vocal fold. Follow-up was performed at 4, 8, and 12 months. The primary outcome was improved mucosal waves. Secondary outcomes included Voice Handicap Index (VHI)-30, patient reported voice quality outcomes, and perceptual analysis of voice.ResultsFifteen subjects received ACF and six received saline injections. At 4, 8, and 12 months after ACF treatments, a significant improvement in mucosal wave grade relative to baseline was observed in both vocal scar and ARVA groups. Relative to control group, mucosal waves were significantly improved in the ARVA group at 4 and 8 months. Perceptual analysis significantly improved in the vocal scar group 12 months after ACF treatments compared to controls. Vocal scar group reported significantly improved vocal quality from baseline. VHI and expert rater voice grade improved in both groups, but did not achieve significance. No adverse events related to fibroblast injections were observed.ConclusionsIn this cohort, injection of ACFs into the vocal fold lamina propria (LP) was safe and significantly improved mucosal waves in patients with vocal scar and ARVA. ACF may hold promise to reconstruct the LP.Level of evidence1 Laryngoscope, 130:2650-2658, 2020.

Objectives/hypothesisUnilateral ML is a commonly performed surgery for dysphonia secondary to glottic insufficiency. The safety of this procedure performed in the outpatient setting has not been extensively examined. The purpose of the study was to assess the safety of outpatient unilateral ML in adults and determine the incidence and timing of postoperative complications across two tertiary-care academic medical centers.Study designRetrospective chart review, METHODS: A review of patients undergoing unilateral ML at two tertiary-care academic centers from 2011 to 2017 was performed. Patients undergoing bilateral medialization laryngoplasty, revision surgery, or those undergoing additional laryngeal framework procedures including arytenoid adduction were excluded. Patient demographics, operative details, and perioperative and postoperative complications were recorded. Comparisons were made between those individuals who underwent inpatient versus outpatient ML.ResultsOne hundred three total procedures met inclusion criteria. Fifty-seven were performed as outpatient procedures, and 46 individuals were observed for at least 23 hours following surgery. Silastic or Gore-Tex implants were used in all but two surgeries. There were no postoperative complications in either setting, including hematoma, dyspnea, wound infections or seromas.ConclusionsThe incidence of adverse events during and immediately following unilateral ML is very low. Patients can be discharged safely the day of surgery without geographic restrictions.Level of evidence4 Laryngoscope, 129:1647-1649, 2019.

Objectives/hypothesisDetermine the rate, diagnoses, and risk factors associated with 30-day nonelective readmissions for patients undergoing surgery for oropharyngeal cancer.Study designRetrospective cohort study.MethodsWe analyzed the Nationwide Readmissions Database for patients who underwent oropharyngeal cancer surgery between 2010 and 2014. Rates and causes of 30-day readmissions were determined. Multivariate logistic regression was used to identify risk factors for readmission.ResultsAmong 16,902 identified cases, the 30-day, nonelective readmission rate was 10.2%, with an average cost per readmission of $14,170. The most common readmission diagnoses were postoperative bleeding (14.1%) and wound complications (12.6%) (surgical site infection [8.6%], dehiscence [2.3%], and fistula [1.7%]). On multivariate regression, significant risk factors for readmission were major ablative surgery (which included total glossectomy, pharyngectomy, and mandibulectomy) (odds ratio [OR]: 1.29, 95% confidence interval [CI]: 1.06-1.60), advanced Charlson/Deyo comorbidity (OR: 2.00, 95% CI: 1.43-2.79), history of radiation (OR: 1.58, 95% CI: 1.15-2.17), Medicare (OR: 1.34, 95% CI: 1.06-1.69) or Medicaid (OR: 1.82, 95% CI: 1.32-2.50) payer status, index admission from the emergency department (OR: 1.19, 95% CI: 1.02-1.40), and length of stay ≥6 days (OR: 1.57, 95% CI: 1.19-2.08).ConclusionsIn this large database analysis, we found that approximately one in 10 patients undergoing surgery for oropharyngeal cancer is readmitted within 30 days. Procedural complexity, insurance status, and advanced comorbidity are independent risk factors, whereas postoperative bleeding and wound complications are the most common reasons for readmission.Level of evidence4. Laryngoscope, 129:910-918, 2019.

ObjectivesLaryngeal function requires neuromuscular activation of the intrinsic laryngeal muscles (ILMs). Rapid activation of the ILMs occurs in cough, laughter, and voice-unvoiced-voiced segments in speech and singing. Abnormal activation is observed in hyperfunctional disorders such as vocal tremor and dystonia. In this study, we evaluate the dynamics of ILM contraction.Study/designBasic science study in an in vivo canine model.MethodsThe following ILMs were stimulated: thyroarytenoid (TA), lateral cricoarytenoid/interarytenoid (LCA/IA), cricothyroid (CT), all laryngeal adductors (LCA/IA/TA), and the posterior cricoarytenoid (PCA). Neuromuscular stimulation was performed via the respective nerves at current levels needed to achieve maximum vocal fold posture change. Muscle contraction and posture changes were recorded with high speed video (HSV). HSV frames were then analyzed to measure response times required from the onset of muscle contraction to the time the vocal folds achieved maximum posture change.ResultsIn all muscles, the onset of posture change occurred within 10 to 12 milliseconds after neuromuscular stimulation. The average times ( ± standard deviation) to achieve final posture were as follows: TA 34.5 ± 6 ms (N = 15), LCA/IA 55 ± 12 ms (N = 14), recurrent laryngeal nerve 43 ± 8 ms (N = 18), CT 100.8 ± 17 ms (N = 26), and PCA 91.2 ± 8 ms (N = 3). Data distribution appeared normal.ConclusionResults showed a difference in muscle activation time between different ILMs consistent with reported differences in muscle fiber composition. These data also provide an estimate of the limits of laryngeal contraction frequency in physiologic and pathologic laryngeal states.Level of evidenceNA Laryngoscope, 129:E21-E25, 2019.

Objectives/hypothesisIn 1974, Minoru Hirano proposed his theory of voice production that is now known as the cover-body theory. He described the thyroarytenoid (TA) and cricothyroid (CT) muscles as the major determinants of vocal fold shape and stiffness, and theorized four typical laryngeal configurations resulting from unique TA/CT activations, with implications for the resulting voice quality. In this study, we directly observed the vocal fold medial surface shape under Hirano's unique TA/CT activation conditions to obtain a three-dimensional (3D) understanding of these laryngeal configurations during muscle activation.Study designIn vivo canine hemilarynx model.MethodsFlesh points were marked along the medial surface of the vocal fold. Selective TA and CT activation were performed via respective laryngeal nerves. 3D reconstructions of the vocal fold medial surface were derived using digital image correlation.ResultsLow level TA and CT activation yielded anteroposterior lengthening and vertical thinning of the vocal fold. When TA activation is far greater than CT, the vocal fold shortens and thickens. With slightly greater TA than CT, activation the vocal length is maintained on average, whereas its vertical thickness decreases. With CT far greater than TA activation, the vocal fold lengthens and thins. In all conditions, glottal contour changes remained minimal.ConclusionsAnalysis of the 3D geometry of the vocal fold medial surface under Hirano's four typical laryngeal configurations revealed that the key geometric changes during TA/CT interactions lie within the anteroposterior length and the vertical thickness of the vocal fold.Level of evidenceNA. Laryngoscope, 128:1412-1418, 2018.

Objectives/hypothesisVocal fold paresis and paralysis are common conditions. Treatment options include augmentation laryngoplasty and voice therapy. The optimal management for this condition is unclear. The objective of this study was to assess possible neuromuscular compensation mechanisms that could potentially be used in the treatment of vocal fold paresis and paralysis.Study designIn vivo canine model.MethodsIn an in vivo canine model, we examined three conditions: 1) unilateral right recurrent laryngeal nerve (RLN) paresis and paralysis, 2) unilateral superior laryngeal nerve (SLN) paralysis, and 3) unilateral vagal nerve paresis and paralysis. Phonatory acoustics and aerodynamics were measured in each of these conditions. Effective compensation was defined as improved acoustic and aerodynamic profile.ResultsThe most effective compensation for all conditions was increasing RLN activation and decreasing glottal gap. Increasing RLN activation increased the percentage of possible phonatory conditions that achieved phonation onset. SLN activation generally led to decreased number of total phonation onset conditions within each category. Differential effects of SLN (cricothyroid [CT] muscle) activation were seen. Ipsilateral SLN activation could compensate for RLN paralysis; normal CT compensated well in unilateral SLN paralysis; and in vagal paresis/paralysis, contralateral SLN and RLN displayed antagonistic relationships.ConclusionsMethods to improve glottal closure should be the primary treatment for large glottal gaps. Neuromuscular compensation is possible for paresis. This study provides insights into possible compensatory mechanisms in vocal fold paresis and paralysis.Level of evidenceNA Laryngoscope, 127:1633-1638, 2017.

Objectives/hypothesisAlthough the geometry of the vocal fold medial surface affects voice quality and is critical in the treatment of glottic insufficiency, the prephonatory shape of the vocal fold medial surface is not well understood. In this study, we activated intrinsic laryngeal muscles individually and in combinations, and recorded the temporal sequence and precise three-dimensional configurational changes of the vocal fold medial surface.Study designIn vivo canine hemilarynx model.MethodsA hemilaryngectomy was performed in an in vivo canine model and ink was used to mark the medial surface of the in situ vocal fold in a grid-like fashion. The thyroarytenoid (TA), lateral cricoarytenoid (LCA), cricothyroid (CT), and posterior cricoarytenoid (PCA) muscles were stimulated individually and in combinations. A right-angle prism whose hypotenuse formed the glottal midline provided two distinct views of the medial surface for a high-speed digital camera. Image-processing package DaVis (LaVision Inc., Goettingen, Germany) allowed time series cross-correlation analysis for three-dimensional deformation calculations of the vocal fold medial surface.ResultsCombined TA and LCA activation yields an evenly adducted rectangular glottal surface. Addition of thyroarytenoid to cricoarytenoid adducts the vocal fold from inferior to superior in a graded fashion allowing formation of a divergent glottis. Posterior cricoarytenoid has a bimodal relationship with thyroarytenoid favoring abduction. Cricothyroid and lateral cricoarytenoid yield unique glottal postures necessary but likely not conducive for efficient phonation.ConclusionsUnderstanding the three-dimensional geometry of the vocal fold medial surface will help us better understand the cause-effect relationship between laryngeal physiology and phonation.Level of evidenceNA Laryngoscope, 127:656-664, 2017.

IntroductionIn speech and singing, the intrinsic laryngeal muscles set the prephonatory posture prior to the onset of phonation. The timing and shape of the prephonatory glottal posture can directly affect the resulting phonation type. We investigated the dynamics of human laryngeal phonatory posturing.MethodsOnset of vocal fold adduction to phonation was observed in 27 normal subjects using high-speed video recording. Subjects were asked to utter a variety of phonation types (modal, breathy, pressed, /i/ following sniff). Digital videokymography with concurrent acoustic signal was analyzed to assess the timing of the following: onset of adduction to final phonatory posture (FPT), phonation onset time (POT), and phonatory posture time (PPT). Final phonatory posture time was determined as the moment at which the laryngeal configuration used in phonation was first achieved.ResultsThirty-three audiovisual recordings met inclusion criteria. Average FPT, PPT, and POT were as follows: 303, 106, and 409 ms for modal; 430, 104, and 534 ms for breathy; 483, 213, and 696 ms for pressed; and 278, 98, and 376 ms for sniff-/i/. The following posturing features were observed: 1) pressed phonation: increased speed of closure just prior to final posture, complete glottal closure, and increased supraglottic hyperactivity; and 2) breathy phonation: decreased speed of closure prior to final posture, increased posterior glottal gap, and increased midmembranous gap.ConclusionsPhonation onset latency was shortest for modal and longest for pressed voice. These findings are likely explained by glottal resistance and subglottal pressure requirements.Level of evidenceNA. Laryngoscope, 126:1837-1843, 2016.

Objectives/hypothesisFundamental frequency (F0) and intensity sound pressure level (SPL) of voice are controlled by intrinsic laryngeal muscle (ILM) activation and subglottal pressure (Psub). Their interactions were investigated.MethodsIn an in vivo canine model, the thyroarytenoid (TA), lateral cricoarytenoid/interarytenoid (LCA/IA), and cricothyroid (CT) muscles were independently activated from threshold to maximal contraction by neuromuscular stimulation in various combinations, whereas airflow was increased to phonation onset pressure and beyond. The resultant acoustic output was analyzed for effects of Psub on vibratory stability, F0, and SPL. Muscle activation plots and vocal range profiles by individual ILM activation states were analyzed.ResultsCricothyroid activation increased phonation onset F0, but vibration was less stable in high CT conditions and displayed vibratory mode change. In addition, a decrease in F0 with increased Psub was observed in high CT conditions. Intensity increased with Psub in all conditions, but the slope was greater at high CT, low TA/LCA/IA activations. Lateral cricoarytenoid/interarytenoid activation improved vocal efficiency. To maintain same F0 with increasing SPL (messa di voce), TA activation was decreased and LCA/IA activation was increased. The same F0 and SPL could be achieved with a variety of ILM activation combinations.ConclusionCricothyroid is primarily required for increasing F0, whereas TA can increase or decrease F0 and SPL. Lateral cricoarytenoid/interarytenoid activation likely maintains vocal fold adduction during increased Psub and improves vocal efficiency. This study also demonstrates laryngeal motor equivalence, the ability of the larynx to achieve the same target F0 and SPL with multiple combinations of ILM activation.Level of evidenceN/A. Laryngoscope, 126:1123-1130, 2016.

Objectives/hypothesisLaryngeal adductor muscle dysfunction is a common cause of voice disorders. Reconstitution of adductor muscle function is often the target of therapy, but the effects of these muscles on voice production remain to be fully understood. This study investigated the differential roles of thyroarytenoid (TA) and lateral cricoarytenoid (LCA) muscles on voice production.Study designBasic science study using an in vivo canine model of phonation.MethodsThe TA and LCA muscle nerve branches were stimulated to obtain seven graded levels of muscle activation, from threshold to maximal contraction. The effects of LCA muscle activation alone, TA muscle activation alone, and combined TA and LCA muscle activation on phonation onset parameters were investigated. Phonatory posture, phonation onset type, fundamental frequency (F0), phonation onset pressure, and airflow were evaluated.ResultsLCA muscle activation closed the posterior glottis, but the midmembranous gap remained. TA muscle activation closed the membranous glottis, but the posterior gap remained. Complete glottal closure was obtained only with combined TA and LCA muscle activation. Phonation onset with the LCA muscle alone was characterized by multiple modes (soft, aperiodic, periodic), whereas with the TA muscle alone it was abrupt and periodic but had significant baseline noise. Combined muscle activation led to elimination of baseline noise with stable abrupt periodic onset of phonation. Combined muscle activation was also necessary for F0 variation. The LCA muscle assisted the TA muscle in increasing subglottal pressure while concurrently reducing phonation onset airflow.ConclusionsThe TA muscle is necessary for F0 variation, stable onset phonation, and increased subglottal pressure, but needs the LCA muscle for optimal effectiveness and to reduce airflow requirements with increased activation.Level of evidenceNA.

Objectives/hypothesisAn animal vocal fold replacement model is needed to investigate treatments for vocal fold scarring. We developed a rabbit surgical model, hypothesizing that orthotopic vocal fold cover implants would attach and survive. We further hypothesized that superficial scarring would be limited, allowing unimpeded vibration.Study designTranslational research: animal surgical study.MethodsRabbit vocal fold covers were excised and immediately reimplanted. After 4 weeks, rabbits were phonated and vibration was recorded with high-speed videography. Larynges were then excised, elastic moduli measured by indentation, and covers sectioned for histology.ResultsFive of six rabbits survived. Phonation was achieved in all, with mucosal waves evident. Elastic modulus did not differ significantly from contralateral uninjured control vocal folds. Histology demonstrated epithelial integrity, partial preservation of elastic fibers, and variable degrees of collagen deposition.ConclusionsVocal fold cover implantation in rabbits is feasible, and grafts survived. Attachment onto the thyroarytenoid muscle prevented excessive scarring, maintained tissue mechanics, and preserved mucosal vibration.Level of evidenceNA.

Objectives/hypothesisMedialization thyroplasty (MT) is commonly used to treat glottic insufficiency. In this study, we investigated the phonatory effects of MT implant medialization depth and medial surface shape.MethodsRecurrent laryngeal nerve (RLN) and vagal paralysis were simulated in an in vivo canine. A type 1 MT was performed using a silicone elastomer implant with variable medialization depths and medial surface shapes: rectangular, V-shaped, divergent, and convergent. The effects on phonation onset flow/pressure relationships and acoustics were measured.ResultsIncreasing depth of medialization led to improvements in fundamental frequency (F0) range and normalization of the slope of pressure/flow relationship toward baseline activation conditions. The effects of implant medial shape also depended on depth of medialization. Outcome measures were similar among the implants at smaller medialization depths. With large medialization depths and vagal paralysis conditions, the divergent implant maintained pressure/flow relationship closer to baseline. The vagal paralysis conditions also demonstrated decreased fundamental frequency range and worse flow/pressure relationship compared to RLN paralysis.ConclusionsThe depth and medial shape of a medialization laryngoplasty (ML) implant significantly affect both the F0 range and aerodynamic power required for phonation. These effects become more notable with increasing depth of medialization. The study also illustrates that ML is less effective in vagal paralysis compared to RLN paralysis.Level of evidenceN/A.

Objectives/hypothesisEvaluate the influence of asymmetric recurrent laryngeal nerve (RLN) stimulation on the vibratory phase, acoustics and aerodynamics of phonation.Study designBasic science study using an in vivo canine model.MethodsThe RLNs were symmetrically and asymmetrically stimulated over eight graded levels to test a range of vocal fold activation conditions from subtle paresis to paralysis. Vibratory phase, fundamental frequency (F0 ), subglottal pressure, and airflow were noted at phonation onset. The evaluations were repeated for three levels of symmetric superior laryngeal nerve (SLN) stimulation.ResultsAsymmetric laryngeal adductor activation from asymmetric left-right RLN stimulation led to a consistent pattern of vibratory phase asymmetry, with the more activated vocal fold leading in the opening phase of the glottal cycle and in mucosal wave amplitude. Vibratory amplitude asymmetry was also observed, with more lateral excursion of the glottis of the less activated side. Onset fundamental frequency was higher with asymmetric activation because the two RLNs were synergistic in decreasing F0 , glottal width, and strain. Phonation onset pressure increased and airflow decreased with symmetric RLN activation.ConclusionAsymmetric laryngeal activation from RLN paresis and paralysis has consistent effects on vocal fold vibration, acoustics, and aerodynamics. This information may be useful in diagnosis and management of vocal fold paresis.Level of evidenceN/A.

Objectives/hypothesisThe posterior cricoarytenoid (PCA) muscle is the sole abductor of the glottis and serves important functions during respiration, phonation, cough, and sniff. The present study examines vocal fold abduction dynamics during PCA muscle activation.Study designBasic science study using an in vivo canine model and human subjects.MethodsIn four canines and five healthy humans vocal fold abduction time was measured using high-speed video recording. In the canines, PCA muscle activation was achieved using graded stimulation of the PCA nerve branch. The human subjects performed coughing and sniffing tasks. High-speed video and audio signals were concurrently recorded.ResultsIn the canines, the vocal fold moved posteriorly, laterally, and superiorly during abduction. Average time to reach 10%, 50%, and 90% abduction was 23, 50, and 100 ms with low stimulation; 24, 58, and 129 ms with medium stimulation; and 21, 49, and 117 ms with high-level stimulation, respectively. In the humans, 100% abduction times for coughing and sniffing tasks were 79 and 193 ms, respectively.ConclusionsThe PCA abduction times in canines are within the range in humans. The results also further support the notion that PCA muscles are fully active during cough.

Objectives/hypothesisTo describe indications, management, and outcomes of endoscopic CO2 laser cricopharyngeal myotomy (CPM).Study designCase series with chart review.MethodsAll patients treated with endoscopic CO2 laser CPM over a 6-year period were identified. A retrospective chart review was performed for surgical indication, history and physical examinations, and swallow evaluations. Swallowing outcomes were assessed using the Functional Outcome Swallowing Scale (FOSS); findings were compared across groups.ResultsEighty-seven patients underwent endoscopic CO2 laser CPM during the study period for cricopharyngeal dysfunction. Indications included Zenker's diverticulum (ZD) (39), DiGeorge syndrome (two), stroke (five), nerve injury (two), radiation for head and neck cancer (15), idiopathic (16), hyperfunctional tracheoesophageal speech (five) and dysphagia from cricopharyngeus stricture after laryngectomy (three). Mean, median, and mode time to feeding postoperatively were 1.4, 1, and 0 days respectively. Mean, median, and mode hospital stays were 1.8, 1, and 1 day respectively. Overall, FOSS scores improved from 2.6 to 1.6 (P

ObjectivesTo determine symptoms and findings in patients with dysphagia related to epiglottic dysfunction. To analyze outcomes in patients who underwent partial epiglottidectomy due to dysphagia related to epiglottic dysfunction.Study designReview and analysis of clinical data obtained as part of the diagnosis and treatment of patients with dysphagia related to epiglottic dysfunction.MethodsA retrospective review was performed of all post-treatment head and neck cancer patients who underwent epiglottidectomy at a single tertiary care referral center. Objective pre- and postprocedure swallow findings, endoscopic evaluation, and subjective improvement based on patient self-reports were reviewed.ResultsSeven patients were identified based on endoscopic evaluation and modified barium swallow study (MBSS) as having epiglottic pathology leading to dysphagia. Specific anatomic and functional findings included thickening of the epiglottis, absence of epiglottic deflection, vallecular bolus retention during and after the swallow, and bolus backflow from the pharynx to the oral or nasal cavity. Partial epiglottidectomy was performed in these patients. Postoperative MBSS was analyzed for changes in swallow efficiency and safety. Nearly all patients demonstrated improved pharyngeal bolus passage with little to no added swallowing morbidity.ConclusionsPreliminary findings suggest a role for partial epiglottidectomy in post-treatment head and neck cancer patients with swallowing disorders. Ideal candidates have intact tongue base contraction and poor retroflexion of the epiglottis, which results in bolus obstruction at the level of the valleculae. Partial epiglottic resection enables improved bolus passage in the pharyngeal phase. Minimal postoperative morbidity occurs in the appropriately selected patient.

Objectives/hypothesisEvaluate the effects of asymmetric superior laryngeal nerve stimulation on the vibratory phase, laryngeal posture, and acoustics.Study designBasic science study using an in vivo canine model.MethodsThe superior laryngeal nerves were symmetrically and asymmetrically stimulated over eight activation levels to mimic laryngeal asymmetries representing various levels of superior laryngeal nerve paresis and paralysis conditions. Glottal posture change, vocal fold speed, and vibration of these 64 distinct laryngeal-activation conditions were evaluated by high speed video and concurrent acoustic and aerodynamic recordings. Assessments were made at phonation onset.ResultsVibratory phase was symmetric in all symmetric activation conditions, but consistent phase asymmetry toward the vocal fold with higher superior laryngeal-nerve activation was observed. Superior laryngeal nerve paresis and paralysis conditions had reduced vocal fold strain and fundamental frequency. Superior laryngeal nerve activation increased vocal fold closure speed, but this effect was more pronounced for the ipsilateral vocal fold. Increasing asymmetry led to aperiodic and chaotic vibration.ConclusionsThis study directly links vocal-fold tension asymmetry with vibratory phase asymmetry, in particular the side with greater tension leads in the opening phase. The clinical observations of vocal fold lag, reduced vocal range, and aperiodic voice in superior laryngeal paresis and paralysis is also supported.