Minimizing Thermal Damage During Thulium Laser-Assisted Partial Arytenoidectomy: Pulsed Versus Continuous Cutting in an Ex-Vivo Calf Model.

OBJECTIVES: The 2 µm-wavelength thulium laser is an effective cutter during partial arytenoidectomy, but thermal trauma can damage adjacent laryngeal tissue. Pulsing laser energy may reduce trauma when compared to continuous-wave cutting. This study measured temperature changes, thermal trauma, and time to complete partial arytenoidectomy, with and without pulsing, in an ex-vivo calf model. METHODS: Tissue temperature and time to complete a trans-cartilaginous cut were measured during partial arytenoidectomy on ex-vivo calf vocal folds (N = 24) using a thulium laser in continuous-wave (CW, N = 12) and pulsed-wave (PW, N = 12) modes. Energy was 5 W for CW and PW cuts; pulse-widths were 250, 500, and 750 ms. Thermal damage was analyzed histologically by measuring the depth of lactate dehydrogenase (LDH) inactivation perpendicular to the laser-cut edge at the vocal process. Paired t-tests compared CW and PW modes. RESULTS: Change in temperature was lower using CW (6.5°C) compared to PW modes (250 ms = 18°; 500 ms = 16°; 750 = 19°; P < .05). Trans-cartilaginous cuts were completed faster using CW (37 seconds) compared to PW (250 ms = 136 seconds; 500 ms = 61 seconds; 750 = 44 seconds; P < .05), and both modes delivered the same total Joules. The average depth of LDH depletion (thermal damage) was similar for all cuts. CONCLUSIONS: 1. Thulium laser cuts in continuous-mode unexpectedly produced less tissue heating yet created similar thermal damage than pulsed-mode cuts during simulated partial arytenoidectomy. 2. Trans-cartilaginous cuts were completed significantly faster in continuous-mode as compared to pulsed-mode cutting. 3. Pulsing the thulium laser does not minimize thermal damage compared to continuous wave cutting during thulium laser-assisted partial arytenoidectomy.

The Impact of Tonsillectomy on the Adult Singing Voice: Acoustic and Aerodynamic Measures.

OBJECTIVE: Singers undergoing tonsillectomy are understandably concerned about possible sequelae to their voice. The surgical risks of laryngeal damage from intubation and upper airway scarring are valid reasons for singers to carefully consider their options for treatment of tonsil-related symptoms. No prior studies have statistically assessed objective voice outcomes in a group of adult singers undergoing tonsillectomy. This study determined the impact of tonsillectomy on the adult singing voice by determining if there were statistically significant changes in preoperative versus postoperative acoustic, aerodynamic, and Voice-Related Quality of Life (VRQOL) measures. STUDY DESIGN: Prospective cohort study. SETTING: Tertiary Referral Academic Hospital SUBJECTS: Thirty singers undergoing tonsillectomy from 2012 to 2019. METHODS: Acoustic recordings were obtained with Computerized Speech Lab (CSL) (Pentax CSL 4500) and analyzed with the Multidimensional Voice Program (MDVP) (Pentax MDVP) and Pratt Acoustic Analysis Software. Estimates of aerodynamic vocal efficiency were obtained and analyzed using the Phonatory Aerodynamic System (Pentax PAS 6600). Preoperative VRQOL scores were recorded, and singers were instructed to refrain from singing for 3 weeks following tonsillectomy. Repeat acoustic and aerodynamic measures as well as VRQOL scores were obtained at the first postoperative visit. RESULTS: Average postoperative acoustic (jitter, shimmer, HNR) and aerodynamic (sound pressure level divided by subglottal pressure) parameters related to laryngeal phonatory function did not differ significantly from preoperative measures. The only statistically significant change in postoperative measures of resonance was a decrease in the 3rd formant (F3) for the /a/ vowel. Average postoperative VRQOL scores (79.8, SD18.7) improved significantly from preoperative VRQOL scores (89, SD12.2) (P = 0.007). CONCLUSIONS: Tonsillectomy does not appear to alter laryngeal voice production in adult singers as measured by standard acoustic and aerodynamic parameters. The observed decrease in F3 for the /a/ vowel is hypothetically related to increasing the pharyngeal cross-sectional area by removing tonsillar tissue, but this would not be expected to appreciably impact the perceptual characteristics of the vowel. Singers' self-assessment (VRQOL) improved after tonsillectomy.

Lions and brown bears colonized North America in multiple synchronous waves of dispersal across the Bering Land Bridge.

The Bering Land Bridge connecting North America and Eurasia was periodically exposed and inundated by oscillating sea levels during the Pleistocene glacial cycles. This land connection allowed the intermittent dispersal of animals, including humans, between Western Beringia (far northeast Asia) and Eastern Beringia (northwest North America), changing the faunal community composition of both continents. The Pleistocene glacial cycles also had profound impacts on temperature, precipitation and vegetation, impacting faunal community structure and demography. While these palaeoenvironmental impacts have been studied in many large herbivores from Beringia (e.g., bison, mammoths, horses), the Pleistocene population dynamics of the diverse guild of carnivorans present in the region are less well understood, due to their lower abundances. In this study, we analyse mitochondrial genome data from ancient brown bears (Ursus arctos; n = 103) and lions (Panthera spp.; n = 39), two megafaunal carnivorans that dispersed into North America during the Pleistocene. Our results reveal striking synchronicity in the population dynamics of Beringian lions and brown bears, with multiple waves of dispersal across the Bering Land Bridge coinciding with glacial periods of low sea levels, as well as synchronous local extinctions in Eastern Beringia during Marine Isotope Stage 3. The evolutionary histories of these two taxa underline the crucial biogeographical role of the Bering Land Bridge in the distribution, turnover and maintenance of megafaunal populations in North America.

Changes in the Daily Phonotrauma Index Following the Use of Voice Therapy as the Sole Treatment for Phonotraumatic Vocal Hyperfunction in Females.

Purpose The aim of this study was to use the Daily Phonotrauma Index (DPI) to quantify group-based changes in the daily voice use of patients with phonotraumatic vocal hyperfunction (PVH) after receiving voice therapy as the sole treatment. This is part of an ongoing effort to validate an updated theoretical framework for PVH. Method A custom-designed ambulatory voice monitor was used to collect 1 week of pre- and posttreatment data from 52 female patients with PVH. Normative weeklong data were also obtained from 52 matched controls. Each week was represented by the DPI, which is a combination of neck-surface acceleration magnitude skewness and the standard deviation of the difference between the first and second harmonic magnitudes. Results Compared to pretreatment, the DPI statistically decreased towards normal in the patient group after treatment (Cohen's d = -0.25). The posttreatment patient group's DPI was still significantly higher than the control group (d = 0.68). Conclusions The DPI showed the pattern of improved ambulatory voice use in a group of patients with PVH following voice therapy that was predicted by the updated theoretical framework. Per the prediction, voice therapy was associated with a decreased potential for phonotrauma in daily voice use, but the posttreatment patient group data were still significantly different from the normative control group data. This posttreatment difference is interpreted as reflecting the impact on voice use of the persistence of phonotrauma-induced structural changes to the vocal folds. Further validation of the DPI is needed to better understand its potential clinical use.

Surgeon Positioning During Awake Laryngeal Surgery: An Ergonomic Analysis.

OBJECTIVES: While it is acknowledged that otolaryngologists performing microlaryngeal surgery can develop musculoskeletal symptoms due to suboptimal body positioning relative to the patient, flexible laryngoscopy and awake laryngeal surgeries (ALSs) can also pose ergonomic risk. This prospective study measured the effects of posture during ergonomically good and bad positions during laryngoscopy using ergonomic analysis, skin-surface electromyography (EMG), and self-reported pain ratings. STUDY DESIGN: Prospective cohort study. METHODS: Eight participants trained in laryngoscopy assumed four ergonomically distinct standing positions (side/near, side/far, front/near, front/far) at three different heights (neutral-top of patient's head in line with examiner's shoulder, high-6 inches above neutral, and low-6 inches below neutral) in relation to a simulated patient. Participants' postures were analyzed using the validated Rapid Upper Limb Assessment (RULA, 1 [best] to 7 [worst]) tool for the 12 positions. Participants then simulated ALS for 10 minutes in a bad position (low-side-far) and a good position (neutral-front-near) with 12 EMG sensors positioned on the limbs and torso. RESULTS: The position with the worst RULA score was the side/near/high (7.0), and the best was the front/near/neutral (4.5). EMG measurements revealed significant differences between simulated surgery in the bad and good positions, with bad position eliciting an average of 206% greater EMG root-mean-squared magnitude across all sampled muscles compared to the good posture (paired t-test, df = 7, P < .01), consistent with self-reported fatigue/pain when positioned poorly. CONCLUSION: Quantitative and qualitative measurements demonstrate the impact of surgeon posture during simulated laryngoscopy and suggest ergonomically beneficial posture that should facilitate ALSs. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2752-2758, 2021.

Optimal Arytenoid Position in Laryngeal Framework Surgery: An Anatomic Human Larynx Study.

OBJECTIVES: The purpose of this study was to better understand the effects of stitch placement on arytenoid medialization by measuring normative cricoarytenoid joint anatomy and changes in arytenoid position when varying arytenopexy stitch configuration. METHODS: This adult human larynx study was done in two parts. First, measurements of the cricoid and arytenoid cartilage anatomy relevant to cricoarytenoid joint function were made in 45 preserved larynges (26 male (M), 19 female (F)) using digital calipers. Second, the arytenoids of six fresh larynges ( three M, three F) were sutured to the cricoid using various arytenopexy-stitch placements ranging from inferior-lateral to superior-medial, and the resulting arytenoid positions were compared by measuring medial displacement of the arytenoid body and change in glottal configuration from macro still images using Image J. Paired t-tests were used to compare the results. RESULTS: Cartilage and joint facet dimensions showed differences between males (M) and females (F). Cricoid facet lengths averaged 9.3 mm (M) and 7.1 mm (F), and widths averaged 4.9 mm (M) and 4.0 mm (F). The arytenoid facet widths averaged 10.5 mm (M) and 9.7 mm (F). Average distances between cricoid facets were 11.8 mm for both males and females. Securing the arytenoid superior-medially on the cricoid facet produced more medialization (2.2 mm vs 1.0 mm, P < .001) and better glottic aperture configuration (9.5° vs 2.7°, P < .001) than securing the arytenoid inferior-laterally on the facet. CONCLUSIONS: Anatomic consistency in cricoarytenoid anatomy provides reliable surgical landmarks for ideal placement of an arytenopexy suture to optimally reposition the arytenoid cartilage. Optimal arytenoid medialization can be accurately reproduced with an arytenopexy-suture that is placed superior-medially on the cricoid facet. LEVEL OF EVIDENCE: NA Laryngoscope, 131:2540-2544, 2021.

Differences in Daily Voice Use Measures Between Female Patients With Nonphonotraumatic Vocal Hyperfunction and Matched Controls.

Purpose The purpose of this study was to obtain a more comprehensive understanding of the pathophysiology and impact on daily voice use of nonphonotraumatic vocal hyperfunction (NPVH). Method An ambulatory voice monitor collected 1 week of data from 36 patients with NPVH and 36 vocally healthy matched controls. A subset of 11 patients with NPVH were monitored after voice therapy. Daily voice use measures included neck-skin acceleration magnitude, fundamental frequency (f o), cepstral peak prominence (CPP), and the difference between the first and second harmonic magnitudes (H1-H2). Additional comparisons included 118 patients with phonotraumatic vocal hyperfunction (PVH) and 89 additional vocally healthy controls. Results The NPVH group, compared to the matched control group, exhibited increased f o (Cohen's d = 0.6), reduced CPP (d = -0.9), and less positive H1-H2 skewness (d = -1.1). Classifiers used CPP mean and H1-H2 mode to maximally differentiate the NPVH and matched control groups (area under the receiver operating characteristic curve of 0.78). Classifiers performed well on unseen data: the logit decreased in patients with NPVH after therapy; ≥ 85% of the control and PVH groups were identified as "normal" or "not NPVH," respectively. Conclusions The NPVH group's daily voice use is less periodic (CPP), is higher pitched (f o), and has less abrupt vocal fold closure (H1-H2 skew) compared to the matched control group. The combination of CPP mean and H1-H2 mode appears to reflect a pathophysiological continuum in NPVH patients of inefficient phonation with minimal potential for phonotrauma. Further validation of the classification model is needed to better understand potential clinical uses. Supplemental Material https://doi.org/10.23641/asha.14390771.

Differences Between Female Singers With Phonotrauma and Vocally Healthy Matched Controls in Singing and Speaking Voice Use During 1 Week of Ambulatory Monitoring.

Purpose Previous ambulatory voice monitoring studies have included many singers and have combined speech and singing in the analyses. This study applied a singing classifier to the ambulatory recordings of singers with phonotrauma and healthy controls to determine if analyzing speech and singing separately would reveal voice use differences that could provide new insights into the etiology and pathophysiology of phonotrauma in this at-risk population. Method Forty-two female singers with phonotrauma (vocal fold nodules or polyps) and 42 healthy matched controls were monitored using an ambulatory voice monitor. Weeklong statistics (average, standard deviation, skewness, kurtosis) for sound pressure level (SPL), fundamental frequency, cepstral peak prominence, the magnitude ratio of the first two harmonics (H1-H2 ), and three vocal dose measures were computed from the neck surface acceleration signal and separated into singing and speech using a singing classifier. Results Mixed analysis of variance models found expected differences between singing and speech in each voice parameter, except SPL kurtosis. SPL skewness, SPL kurtosis, and all H1-H2 distributional parameters differentiated patients and controls when singing and speech were combined. Interaction effects were found in H1-H2 kurtosis and all vocal dose measures. Patients had significantly higher vocal doses in speech compared to controls. Conclusions Consistent with prior work, the pathophysiology of phonotrauma in singers is characterized by more abrupt/complete glottal closure (decreased mean and variation for H1-H2 ) and increased laryngeal forces (negatively skewed SPL distribution) during phonation. Application of a singing classifier to weeklong data revealed that singers with phonotrauma spent more time speaking on a weekly basis, but not more time singing, compared to controls. Results are used as a basis for hypothesizing about the role of speaking voice in the etiology of phonotraumatic vocal hyperfunction in singers.

The Use of 532-Nanometer-Pulsed Potassium-Titanyl-Phosphate (KTP) Laser in Laryngology: A Systematic Review of Current Indications, Safety, and Voice Outcomes.

OBJECTIVE: To investigate the indications, efficacy, safety, and outcomes of potassium-titanyl-phosphate (KTP) laser procedures for treatment of laryngeal disease. METHODS: PubMed, Cochrane Library, and Scopus were searched for studies providing information about the indications, efficacy, and safety of both in-office and operative suspension microlaryngoscopy KTP laser procedure in treatment of laryngeal disease. Diagnostic criteria and clinical outcome evaluation of included studies were analyzed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. RESULTS: Of the initial screened 140 papers, 17 met our inclusion criteria. Six papers involved KTP laser procedures for benign and malignant vocal fold lesions in suspension microlaryngoscopy only, 10 papers focused on only in-office KTP laser procedures for benign vocal fold lesions, and 1 paper included both in-office and suspension microlaryngoscopy procedures. The following lesions may be considered as indications for KTP laser procedures: Reinke's edema, sulcus vocalis, vocal fold hemorrhage, polyp, granuloma, cyst, scar, papillomatosis, dysplasia, leukoplakia, and early vocal fold malignancies. Irrespective of the types of procedure (in-office vs suspension microlaryngoscopy), the KTP laser is associated with a low complication rate and overall good vocal fold vibration recovery. There is an important heterogeneity among studies concerning laser settings, indications, and outcomes used for the assessment of treatment effectiveness. There are no controlled studies directly comparing KTP laser with other lasers (ie, carbon dioxide laser). CONCLUSION: The use of KTP laser procedures for treatment of laryngeal disease has increased over the past decade, especially for office-based management of vocal fold lesions. Future controlled studies are needed to compare the safety and outcomes of the KTP laser to other techniques.

Patient-Reported Factors Associated with the Onset of Hyperfunctional Voice Disorders.

OBJECTIVES: Prevention, diagnosis, and treatment of hyperfunctional voice disorders would be improved by better understanding their etiological contributing factors. Therefore, this study estimated the prevalence of etiological factors using self-reported data about disorder onset from a large cohort of patients with Phonotraumatic Vocal Hyperfunction (PVH) and Non-Phonotraumatic Vocal Hyperfunction (NPVH). METHODS: Retrospective chart review extracted the self-reported rate (gradual, sudden) and events associated (voice use, anxiety/stress, upper respiratory infection [URI]) with disorder onset from 1,577 patients with PVH and 979 patients with NPVH. RESULTS: Both patient groups reported a gradual onset more than a sudden onset. Voice use was the most frequently reported event for PVH and the NPVH group self-reported all three events at equal frequency. The largest PVH subgroups were associated with voice use while the NPVH subgroups were associated with only voice use, only URI, or only anxiety/stress. CONCLUSION: The results support the general clinical view that PVH is most strongly related to the gradual accumulated effects of phonotrauma, while NPVH has a more heterogeneous etiology. The identified PVH and NPVH subgroups may have clinical relevance and future work could investigate differences in treatment and outcomes among these subgroups.

Changes in a Daily Phonotrauma Index After Laryngeal Surgery and Voice Therapy: Implications for the Role of Daily Voice Use in the Etiology and Pathophysiology of Phonotraumatic Vocal Hyperfunction.

Purpose This study attempts to gain insights into the role of daily voice use in the etiology and pathophysiology of phonotraumatic vocal hyperfunction (PVH) by applying a logistic regression-based daily phonotrauma index (DPI) to predict group-based improvements in patients with PVH after laryngeal surgery and/or postsurgical voice therapy. Method A custom-designed ambulatory voice monitor was used to collect 1 week of pre- and postsurgery data from 27 female patients with PVH; 13 of these patients were also monitored after postsurgical voice therapy. Normative weeklong data were obtained from 27 matched controls. Each week was represented by the DPI, standard deviation of the difference between the first and second harmonic amplitudes (H1-H2). Results Compared to pretreatment, the DPI significantly decreased in the patient group after surgery (Cohen's d effect size = -0.86) and voice therapy (d = -1.06). The patient group DPI only normalized after voice therapy. Conclusions The DPI produced the expected pattern of improved ambulatory voice use across laryngeal surgery and postsurgical voice therapy in a group of patients with PVH. The results were interpreted as providing new objective information about the role of daily voice use in the etiology and pathophysiology of PVH. The DPI is viewed as an estimate of potential vocal fold trauma that relies on combining the long-term distributional characteristics of two parameters representing the magnitude of phonatory forces (neck-surface acceleration magnitude) and vocal fold closure dynamics (H1-H2). Further validation of the DPI is needed to better understand its potential clinical use.

Estimation of Subglottal Pressure From Neck Surface Vibration in Patients With Voice Disorders.

Purpose Given the established linear relationship between neck surface vibration magnitude and mean subglottal pressure (Ps) in vocally healthy speakers, the purpose of this study was to better understand the impact of the presence of a voice disorder on this baseline relationship. Method Data were obtained from participants with voice disorders representing a variety of glottal conditions, including phonotraumatic vocal hyperfunction, nonphonotraumatic vocal hyperfunction, and unilateral vocal fold paralysis. Participants were asked to repeat /p/-vowel syllable strings from loud-to-soft loudness levels in multiple vowel contexts (/pa/, /pi/, /pu/) and pitch levels (comfortable, higher than comfortable, lower than comfortable). Three statistical metrics were computed to analyze the regression line between neck surface accelerometer (ACC) signal magnitude and Ps within and across pitch, vowel, and voice disorder category: coefficient of determination (r 2), slope, and intercept. Three linear mixed-effects models were used to evaluate the impact of voice disorder category, pitch level, and vowel context on the relationship between ACC signal magnitude and Ps. Results The relationship between ACC signal magnitude and Ps was statistically different in patients with voice disorders than in vocally healthy controls; patients exhibited higher levels of Ps given similar values of ACC signal magnitude. Negligible effects were found for pitch condition within each voice disorder category, and negligible-to-small effects were found for vowel context. The mean of patient-specific r 2 values was .63, ranging from .13 to .92. Conclusions The baseline, linear relationship between ACC signal magnitude and Ps is affected by the presence of a voice disorder, with the relationship being participant-specific. Further work is needed to improve ACC-based prediction of Ps, across treatment, and during naturalistic speech production.

Differences in Weeklong Ambulatory Vocal Behavior Between Female Patients With Phonotraumatic Lesions and Matched Controls.

Purpose Previous work using ambulatory voice recordings has shown no differences in average vocal behavior between patients with phonotraumatic vocal hyperfunction and matched controls. This study used larger groups to replicate these results and expanded the analysis to include distributional characteristics of ambulatory voice use and measures indicative of glottal closure. Method Subjects included 180 adult women: 90 diagnosed with vocal fold nodules or polyps and 90 age-, sex-, and occupation-matched controls with no history of voice disorders. Weeklong summary statistics (average, variability, skewness, kurtosis) of voice use were computed from neck-surface acceleration recorded using an ambulatory voice monitor. Voice measures included estimates of sound pressure level (SPL), fundamental frequency (f o), cepstral peak prominence, and the difference between the first and second harmonic magnitudes (H1-H2). Results Statistical comparisons resulted in medium-large differences (Cohen's d ≥ 0.5) between groups for SPL skewness, f o variability, and H1-H2 variability. Two logistic regressions (theory-based and stepwise) found SPL skewness and H1-H2 variability to classify patients and controls based on their weekly voice data, with an area under the receiver operating characteristic curve of 0.85 and 0.82 on training and test sets, respectively. Conclusion Compared to controls, the weekly voice use of patients with phonotraumatic vocal hyperfunction reflected higher SPL tendencies (negatively skewed SPL) with more abrupt glottal closure (reduced H1-H2 variability, especially toward higher values). Further work could examine posttreatment data (e.g., after surgery and/or therapy) to determine the extent to which these differences are associated with the etiology and pathophysiology of phonotraumatic vocal fold lesions.

Efficacy of Videostroboscopy and High-Speed Videoendoscopy to Obtain Functional Outcomes From Perioperative Ratings in Patients With Vocal Fold Mass Lesions.

OBJECTIVES: A major limitation of comparing the efficacy of videostroboscopy (VS) and high-speed videoendoscopy (HSV) is the lack of an objective reference by which to compare the functional assessment ratings of the two techniques. For patients with vocal fold mass lesions, intraoperative measures of lesion size and depth may serve as this objective reference. This study compared the relationships between the pre- to postoperative change in VS and HSV visual-perceptual ratings to intraoperative measures of lesion size and depth. DESIGN: Prospective visual-perceptual study with intraoperative measures of lesion size and depth. METHODS: VS and HSV samples were obtained preoperatively and postoperatively from 28 patients with vocal fold lesions and from 17 vocally healthy controls. Two experienced clinicians rated amplitude, mucosal wave, vertical phase difference, left-right phase asymmetry, and vocal fold edge on a visual-analog scale using both imaging techniques. The change in perioperative ratings from VS and HSV was compared between groups and correlated to intraoperative measures of lesion size and depth. RESULTS: HSV was as reliable as VS for ratings of amplitude and edge, and substantially more reliable for ratings of mucosal wave and left-right phase asymmetry. Both VS and HSV had mild-moderate correlations between change in perioperative ratings and intraoperative measures of lesion area. Change in function could be obtained in more patients and for more parameters using HSV than VS. Group differences were noted for postoperative ratings of amplitude and edge; however, these differences were within one level of the visual-perceptual rating scale. The presence of asynchronicity in VS recordings renders vibratory features either uninterpretable or potentially distorted and thus should not be rated. CONCLUSIONS: Amplitude and edge are robust vibratory measures for perioperative functional assessment, regardless of imaging modality. HSV is indicated for evaluation of subepithelial lesions or if asynchronicity is present in the VS image sequence.

Carbon debris and fiber cleaving: Effects on potassium-titanyl-phosphate laser energy and chorioallantoic membrane model vessel coagulation.

OBJECTIVES/HYPOTHESIS: Photoangiolytic precision afforded by the 532-nm potassium-titanyl-phosphate (KTP) laser relies on predictable energy delivery. Inadequate energy output can cause vessel rupture, and excessive energy can cause thermal damage. The quality of the cleaved surface and carbon deposits from ablated tissue are two factors that could negatively impact fiber performance. The effects of these on energy output and blood vessel coagulation were assessed using a chorioallantoic membrane (CAM) model. STUDY DESIGN: Comparative analysis. METHODS: Laser fibers with carbon debris, optimal fiber cleaving, and suboptimal cleaving were inspected at three times magnification, and the light dispersion pattern of each fiber was rated. The average energy output from consecutive pulses through each fiber configuration was recorded. The effect of these fiber conditions on clinical efficacy was estimated by measuring vessel coagulation versus rupture in the CAM model. Repeated measures analysis of variance compared results. RESULTS: Carbon debris and suboptimal cleaving resulted in decreased energy output in comparison to optimal cleaving ([-Δ244 mJ, d = 4.31, P < .001] and [-Δ195 mJ, d = 6.04, P < .001]). Optimal cleaving resulted in immediate coagulation of vessels. Fibers with suboptimal cleaving and carbon debris had unpredictable outcomes, requiring multiple pulses for coagulation or causing vessel rupture. CONCLUSIONS: KTP laser fiber function is significantly affected by fiber tip condition. Carbon debris and suboptimal cleaving create significant attenuation of energy, which results in an unpredictable angiolytic effect, as demonstrated by increased vessel rupture in the CAM model. Optimal recleaving of KTP laser fibers restores prior energy output and predictable coagulation. Care should be taken to avoid carbon debris on laser-fiber tips and to cleave fibers properly. LEVEL OF EVIDENCE: NA Laryngoscope, 129:2244-2248, 2019.

Glottic Stenosis: An Anatomic Analysis and New Treatment With a Self-Retaining Interarytenoid Spring.

INTRODUCTION:: Endotracheal (ET) intubation is a common cause of acquired glottic stenosis. Severe cases often require an irreversible arytenoidectomy/cordectomy, which typically results in poor voice quality. Adult human cadaver larynges were studied to gain insights about ET tube-induced posterior glottic injuries, hoping to create a less invasive remedy. STUDY DESIGN:: Human cadaver investigation and case reports. METHODS:: Microlaryngeal assessments were done on 10 human cadaver larynges (5 men, 5 women) with and without ET tubes. After supracricoid soft tissue resection, measurements were obtained, including the distance between the outer diameter of the ET tube and the medial aspect of the cricoarytenoid joint facet. Additionally, measurements of the circumferential arc of differently sized ET tubes were made alongside both cricoarytenoid joint capsules. This information was used to design a silastic stent that would function as a self-retaining interarytenoid spring to treat posterior glottic stenosis in 5 patients. Four of 5 patients included in the clinical study were tracheotomy dependent, primarily because of glottic stenosis. The human surgical technique is described in detail. RESULTS:: The shortest distance between the outer diameter of the ET tube to the medial cricoid facet averaged 5.02 mm in men and 3.62 mm in women. On the basis of the diameter of the intralaryngeal component of the initially round stent, and the position of the cricoarytenoid joint facets, the interarytenoid spring would have a subtended arc between 110° and 175°. These data helped fashion parameters for modifying a conventional T-tube to form a new self-retaining silastic interarytenoid spring. The first 5 human cases have been successful, allowing effective tracheotomy tube decannulation and excellent voice quality. CONCLUSIONS:: The anatomic investigation herein provided key insights into ET tube-induced glottic stenosis and facilitated a new straightforward procedure to surgically improve the airway yet preserve excellent vocal function in patients with acquired glottic stenosis. Level of Evidence: NA.

Vocal Fold Motion Recovery in Patients With Iatrogenic Unilateral Immobility: Cervical Versus Thoracic Injury.

OBJECTIVES:: Prognostic information about the return of vocal fold mobility in patients with iatrogenic unilateral vocal fold immobility (UVFI) can help with informed decisions about temporary and permanent treatment options. Although many variables can influence the likelihood of recovery, clinical experience suggests that cervical versus thoracic injury is a determining factor. The purpose of this study was to compare recovery rates from UVFI between cervical and thoracic injuries. METHODS:: A retrospective review of the medical record was performed on all adult patients diagnosed with complete iatrogenic UVFI from 2005 to 2015 (n = 923). Patients with incomplete data and etiologies of idiopathic, malignancy, or stenosis were excluded, leaving a study cohort of 502 patients who were categorized as having UVFI after cervical (n = 329) or thoracic (n = 173) injury. Data regarding site of iatrogenic injury (cervical vs thoracic), mobility status, and time interval to recovery or surgical intervention were recorded and compared using χ2 analyses. RESULTS:: Overall, 15% of patients recovered vocal fold mobility at a median of 4.1 months. Patients with cervical injury (65 of 329 [20%]) were significantly more likely to recover mobility than patients with thoracic injury (11 of 173 [6.4%]) (odds ratio, 3.63). The cervical cohort contained more women (68% vs 31%) and was younger (mean age, 60.4 ± 13.8 vs 64.1 ± 16.1 years; Cohen's D = 0.25). CONCLUSIONS:: Patients with cervical injuries resulting in UVFI are 4 times more likely to recover mobility than patients with thoracic injuries. This information can be valuable in counseling patients with UVFI and may affect clinical decision making.

Wound healing after transoral angiolytic laser surgery for early glottic carcinoma.

OBJECTIVES/HYPOTHESIS: Wound healing after transoral angiolytic laser surgery for early glottic carcinoma was analyzed to identify factors influencing healing and clinical significance of persistent granulation tissue. STUDY DESIGN: Retrospective review. METHODS: A retrospective review of 100 consecutive patients undergoing endoscopic angiolytic laser surgery for T1 and T2 glottic carcinoma was performed. Patients with prior radiation or incomplete data were excluded. Postoperative endoscopic images were analyzed for time to healing, size and location of wound, and presence of granulation tissue. Three blinded, independent raters graded wound appearance and presence of granulation tissue. RESULTS: Seventy-nine patients healed without need for intervention at a median of 3.5 months. Two patients had office-based ablation of granulation without biopsy and healed. The remaining 19 patients had biopsy for granulation tissue. Wounds that underwent biopsy at >3 months were more likely to contain carcinoma (5/6 patients, 83%) than wounds that were biopsied <3 months (2/13 patients, 15%) (P = .004). Presence of granulation significantly correlated with resection involving anterior commissure (P = .01), > 75%vocal fold length (P = .006), and depth into muscle (P = .001). Delayed healing (>3 months) correlated with T2b tumors (P = .02), depth into ligament (P = .002) and anterior commissure involvement (P = .04). T1a carcinomas more commonly healed in <3 months (P = .005). CONCLUSIONS: Many vocal fold wounds heal completely within 3.5 months after angiolytic laser surgery for early glottic carcinoma. Larger and deeper wounds are more likely to heal with granulation tissue. Granulation can resolve without surgical intervention; however, granulation present > 3 months warrants biopsy due to increased risk of malignancy. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:435-440, 2019.

A Comparison of Laser-Protected Endotracheal Tubes.

OBJECTIVES: To compare the physical characteristics of 3 laser-protected endotracheal tubes (LPETs) commonly used in endoscopic laser surgery. To report potential intraoperative problems related to LPET use and suggest practical solutions. STUDY DESIGN: Comparative analysis. SETTING: Academic laboratory. SUBJECTS AND METHODS: Physical characteristics of the Mallinckrodt Laser-Flex (MTL), Medtronic Laser-Shield II (ML-II), and Rusch LaserTubus (RL) were compared. The effect of bending LPETs on airflow resistance was estimated with a pressure transducer. The force required to pull each tube through the glottis and the pressure exerted during this maneuver were measured in a fresh cadaveric human larynx. RESULTS: The design features and physical characteristics of LPETs differ, including varying balloon-tip lengths. Bending LPETs to acute angles caused significant pressure increase within the RL tube (Δ 3.42 cm H2O) and minimal change within the ML-II (Δ 0.12 cm H2O) and MTL (Δ 0.21 cm H2O) tubes. The average force required to pull the RL (48.12 g, P = .003) and MTL (282.4 g, P = .001) tubes through the glottis was 7.6× and 44.5× greater than that for the ML-II (6.39 g). When pulled through the vocal folds, the ML-II cuff exerted no detectable pressure, whereas higher pressures were measured for the RL (2.2 cm H2O) and MTL (6.5 cm H2O) tubes. CONCLUSION: The ML-II tube had the most favorable characteristics, with minimal pressure during extubation and resistance to kinking. The RL tube kinks readily with a resultant increase in resistance to airflow. The MTL tube extends farther into the trachea due to a relatively elongated balloon-tip configuration. Future LPET designs should incorporate features that avoid intraoperative difficulties related to airway protection and ventilation.

Efficient Binding, Protection, and Self-Release of dsRNA in Soil by Linear and Star Cationic Polymers.

Double stranded RNA (dsRNA) exhibits severe degradation within 3 days in live soil, limiting its potential application in crop protection. Herein we report the efficient binding, protection, and self-release of dsRNA in live soil through the usage of a cationic polymer. Soil stability assays show that linear poly(2-(dimethylamino)ethyl acrylate) can delay the degradation of dsRNA by up to 1 week while the star shaped analogue showed an increased stabilization of dsRNA by up to 3 weeks. Thus, the architecture of the polymer can significantly affect the lifetime of dsRNA in soil. In addition, the hydrolysis and dsRNA binding and release profiles of these polymers were carefully evaluated and discussed. Importantly, hydrolysis could occur independently of environmental conditions (e.g., different pH, different temperature) showing the potential for many opportunities in agrochemicals where protection and subsequent self-release of dsRNA in live soil is required.