Surface kinematic and depth-resolved analysis of human vocal folds in vivo during phonation using optical coherence tomography.

SIGNIFICANCE: The human vocal fold (VF) oscillates in multiple vectors and consists of distinct layers with varying viscoelastic properties that contribute to the mucosal wave. Office-based and operative laryngeal endoscopy are limited to diagnostic evaluation of the VF epithelial surface only and are restricted to axial-plane characterization of the horizontal mucosal wave. As such, understanding of the biomechanics of human VF motion remains limited. AIM: Optical coherence tomography (OCT) is a micrometer-resolution, high-speed endoscopic imaging modality which acquires cross-sectional images of tissue. Our study aimed to leverage OCT technology and develop quantitative methods for analyzing the anatomy and kinematics of in vivo VF motion in the coronal plane. APPROACH: A custom handheld laryngeal stage was used to capture OCT images with 800 A-lines at 250 Hz. Automated image postprocessing and analytical methods were developed. RESULTS: Novel kinematic analysis of in vivo, long-range OCT imaging of the vibrating VF in awake human subjects is reported. Cross-sectional, coronal-plane panoramic videos of the larynx during phonation are presented with three-dimensional videokymographic and space-time velocity analysis of VF motion. CONCLUSIONS: Long-range OCT with automated computational methods allows for cross-sectional dynamic laryngeal imaging and has the potential to broaden our understanding of human VF biomechanics and sound production.

Early Adverse Events Following Transcervical Hypopharyngeal Diverticulum Surgery.

OBJECTIVE: To describe rates of short-term morbidity following transcervical surgical treatment of hypopharyngeal diverticulum (HD) and analyze predictors of adverse events. METHODS: The 2005 to 2017 National Surgical Quality Improvement Program database was queried to identify patients diagnosed with HD undergoing open transcervical diverticulectomy. RESULTS: A total of 597 patients with a mean age of 71.4 ± 12.3 years were included. Thirty-day adverse events were experienced by 63 (10.6%) subjects, including 6.5% unplanned reoperations, 4.2% surgical complications, 4.4% medical complications, 2.7% readmissions, and 0.7% deaths. Medical complications notably included pneumonia (2.0%), reintubation (1.2%), sepsis (1.2%), intubation >48 hours (0.5%), urinary tract infection (0.5%), or deep vein thrombosis (0.5%), while surgical complications included organ/space infection (2.0%) and superficial (1.3%) or deep (1.0%) surgical site infection. Gender, race, functional status, diabetes, dyspnea, hypertension, steroid use, and recent weight loss were not associated with adverse events. Length of operation and hospitalization were both higher among those with adverse events (127.4 ± 107.9 vs 95.7 ± 59.8 minutes, P = 0.027, and 7.4 ± 7.4 vs 2.8 ± 3.6 days, P < 0.001). On multivariable logistic regression, high American Society of Anesthesiologists (ASA) class (OR = 2.02, P = 0.017), smoking (OR = 2.10, P = 0.044), and operation time (OR = 1.01; P = 0.005) were independent predictors of adverse events. Obesity was not associated with length of stay, readmission/reoperation, or complications. However, increased age was associated with shorter operations (P = 0.020), higher length of hospitalization (P < 0.001), and higher mortality (P = 0.027) and readmission rates (P = 0.023). CONCLUSION: Understanding clinical factors associated with complications following open surgery for HD such as ASA score, smoking status, length of operation, and age can help optimize surgical outcomes for at-risk patients.

Utilization and Influence of Online Support Communities in Idiopathic Subglottic Stenosis Patients.

OBJECTIVES: To determine the factors that shape utilization of social media-based online support communities (OSCs) and study the influence of these communities on medical decision-making in patients with Idiopathic Subglottic Stenosis (iSGS). STUDY DESIGN: Survey study. METHODS: A survey investigating OSC use was sent to the 1,056 members of the North American Airway Collaborative (NoAAC) iSGS1000 cohort in January 2018. Responses were merged with the existing NoAAC data set containing extensive demographic data, disease-specific history, and responses to validated patient-reported outcome measures. RESULTS: A total of 755 individuals with iSGS and mean age of 51.8 ± 11.6 years were included (99% female, 98% white, 63% college educated) and 58% were OSC users. Younger age, female gender, and college education were each associated with OSC use (P < .05). Users spent 2.5 ± 3.3 hours per week on the platforms. Time spent on OSC was not associated with total number of prior treatments. Higher disease anxiety (FoP-Q, R = 0.26, P < .001), lower social support (MOS, R = -0.12, P = .037), and lower level of shared-decision-making with the treating physician (SDM-Q9, R = -0.16, P = .007) were weakly associated with more hours spent engaging an OSC. OSC use influenced treatment and physician choice in 35% and 26% of users, respectively. Increased time spent on OSC use was associated with increased influence on patient medical decisions regarding treatment, surgery, and physician choice (P < .05). CONCLUSION: OSC engagement is common in patients with iSGS. Disease anxiety, social support, and relationship with the physician may influence OSC utilization. More OSC engagement weakly associated with greater OSC influence on patient medical decision-making. LEVEL OF EVIDENCE: NA. Laryngoscope, 131:1821-1827, 2021.

Surgical management of recurrent Zenker's diverticulum: A multi-institutional cohort study.

OBJECTIVE: This study identifies how recurrent Zenker's diverticula are treated. METHODS: A retrospective chart review was performed from four tertiary referral academic voice and swallowing centers to identify individuals who underwent surgery for recurrent Zenker's diverticulum. Demographic data, surgical modalities for primary and revision surgery, symptoms pre and post revision and complications were recorded. RESULTS: 56 individuals met inclusion criteria. Primary surgery was open in 30.3% (n = 17) and endoscopic in 69.6% (n = 39). Revision surgery was performed via an open approach in 37.5% of cases (N = 21) and via an endoscopic approach in 62.5% of cases (N = 35). Revision surgical technique was based on pouch size, patient age and comorbidities, as well as patient and surgeon preference. There were no major complications and few minor complications. CONCLUSION: Zenker's diverticulum symptoms can recur regardless of primary treatment modality. Both endoscopic and open approaches can safely treat recurrent Zenker's diverticula.

Fiberoptic endoscopic evaluation of swallowing findings in individuals with Zenker's diverticulum and cricopharyngeal bar.

PURPOSE: To assess fiberoptic endoscopic evaluation of swallowing (FEES) findings in individuals with cricopharyngeal bar (CPB) and Zenker's diverticulum (ZD). METHODS: In this retrospective chart review spanning from 2010-2018, individuals diagnosed with CPB or ZD and undergoing FEES were identified. Patient demographics, radiographic studies, and treatments were recorded, and findings were compared between CPB, ZD of < 3 cm, and ZD ≥ 3 cm. RESULTS: Sixty-one individuals consisting of 48 patients with ZD and 13 patients with CPB met inclusion criteria. Post-swallow hypopharyngeal reflux (PSHR) of undigested food bolus, present with or without Valsalva maneuver, was noted in 23%, 84%, and 75% of patients with CPB, ZD < 3 cm, and ZD ≥ 3 cm, respectively. The sensitivity and specificity of the finding for those with ZD were 81% and 83%, respectively. Of patients with ZD, reflux resolved in all but six individuals after surgery. Four of these patients underwent revision surgery with the reflux subsequently resolving, and two patients with persistent reflux were asymptomatic and did not desire further treatment. CONCLUSIONS: PSHR is a good tool to identify the presence of a ZD and is less helpful to identify a CPB. Elimination of PSHR is a good tool to determine treatment success in patients with ZD and CPB. LEVEL OF EVIDENCE: IV.

Is nasogastric tube feeding necessary after hypopharyngeal diverticulum surgery?

OBJECTIVES: Nasogastric tubes (NGT) are often placed after surgery for cricopharyngeal muscle pathology due to risk of infection and mediastinitis. The aim of this study was to examine if this practice is necessary. METHODS: A retrospective case series of subjects who underwent surgery for hypopharyngeal diverticula or cricopharyngeal bars from March 2011 to June 2018 was conducted. Demographic data, type of surgery, placement of feeding tube, initiation of oral feeding, and any complications were recorded. RESULTS: Sixty-four surgeries were performed for Zenker's diverticula (ZD; N = 52), Killian-Jamieson diverticula (N = 2), and cricopharyngeal bar (N = 10). Mean age and ZD pouch size were 74.0 ± 10.6 years and 3.1 ± 1.8 cm, respectively. Procedures included 48 carbon dioxide laser-assisted myotomies, 14 open diverticulectomies, and 2 endoscopic stapler-assisted diverticulotomies. Of the 64 patients, 19 (29.7%) received intraoperative NGTs while the remaining 45 (70.3%) did not receive NGTs. The former cohort had the NGTs removed on post-operative day (POD) 4.5 ± 2.5, and the non-NGT cohort started clear liquid diet (CLD) on POD 1.2 ± 0.7 days, where 38 patients (84.4%) started CLD on POD 1, and 5 patients (7.8%) were started on oral diet on POD 2-4. Over time, fewer NGTs were placed and oral diets were started sooner. There were 5 complications occurring in 3 patients from the NGT cohort (15.5%) and 2 from the non-NGT cohort (4.4%). CONCLUSIONS: Surgery for hypopharyngeal diverticula and CPB may not require routine perioperative NGT placement which can be associated with higher rates of complication. Patients can safely receive CLD on POD 1.

Identification and Management of Chronic Laryngitis.

Chronic laryngitis is an inflammatory process of at least 3 weeks duration and affects phonation, breathing, and swallowing. This article describes the infectious, inflammatory, and autoimmune causes of chronic laryngitis. Symptoms of chronic laryngitis are nonspecific and may range from mild to airway compromise requiring emergent tracheostomy.

Free Flap Versus Pedicled Flap Reconstruction of Laryngopharyngeal Defects: A 10-Year National Surgical Quality Improvement Program Analysis.

OBJECTIVES/HYPOTHESIS: Large defects after total laryngectomy (TL) and total laryngopharyngectomy (TLP) often benefit from free flap (FF) or pedicled flap (PF) reconstruction to maintain continuity of the aerodigestive tract, protect great vessels, or reinforce pharyngeal closure. Although both techniques are commonly used, no consensus exists as to which results in fewer complications. The goal of this study was to determine if 30-day morbidity/mortality outcomes differ between PF and FF reconstruction in patients undergoing TL/TLP. STUDY DESIGN: Retrospective cohort study. METHODS: Patients were analyzed who underwent TL/TLP with reconstruction using records from the American College of Surgeons National Surgical Quality Improvement Program database (2005-2015). RESULTS: A total of 347 patients were included; 204 received FF reconstruction, whereas 143 received PF reconstruction. FF reconstruction was more commonly used with TLP defects (P = .001). The total operative time in the FF (590 ± 140 minutes) was longer than the PF (441 ± 125 minutes) group (P < .0001). There was a higher rate of postoperative transfusions in those undergoing FF reconstruction (P = .022). There was no significant difference in complication rates among TLP patients. Among TL patients only, FF reconstruction had a higher association with wound infections than PFs (P = .040). On multivariate analysis, low hematocrit was associated with complications (P = .031). Age (P = .031) and congestive heart failure exacerbation (P < .001) were associated with increased hospital stay. Overall, there were no differences in readmissions, reoperations, or deaths between the groups. CONCLUSIONS: Reported complication rates after TL/TLP remain high, despite widespread usage of vascularized flaps in reconstruction. This comparison reveals no significant difference in postoperative complications between patients who received PF and FF laryngopharyngeal reconstruction. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:105-112, 2019.

Safety of outpatient unilateral medialization laryngoplasty across two academic institutions.

OBJECTIVES/HYPOTHESIS: Unilateral 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 DESIGN: Retrospective 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. RESULTS: One 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. CONCLUSIONS: The 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 EVIDENCE: 4 Laryngoscope, 129:1647-1649, 2019.

Are Perioperative Antibiotics Necessary During Direct Microlaryngoscopy?

OBJECTIVES/HYPOTHESIS: There are currently no established recommendations for the use of perioperative antibiotics (PAs) to prevent surgical site infections (SSIs) for direct microlaryngoscopy (DML). This study examined the incidence of SSI in patients undergoing DML with and without PAs. STUDY DESIGN: Retrospective, multi-institutional chart review. METHODS: A retrospective, multi-institutional chart review was performed at four tertiary referral academic medical centers. Patients undergoing DML from 2010 to 2017 were identified using Current Procedural Terminology codes. Medical records of patients undergoing DML with biopsy, microsurgery, laser ablation, or vocal fold injection who had adequate follow-up were reviewed. Procedures with significant cartilage destruction, concurrent open surgery, or esophageal surgery were excluded. Data recorded included age, gender, pacemaker history, American Society of Anesthesiologists class, wound class, indication for surgery, use of laser, complications, emergency room visits, hospitalizations, pain, fever, and postoperative steroid and antibiotic prescriptions. Presence or absence of SSIs was evaluated by a fellowship-trained laryngologist. RESULTS: There were 834 patients who met inclusion criteria. Of those, 698 did not receive PAs and 136 received PAs. The median age of patients was 54 years of age in the PA group and 57.5 years of age in the non-PA group, and all cases were recorded as wound class II. Overall, 58% of surgeries involved use of carbon dioxide or potassium-titanyl-phosphate laser. Only one SSI was reported on follow-up in a patient who did receive PAs. CONCLUSIONS: SSIs are exceedingly rare following DML. PA use is not indicated for routine DML. LEVEL OF EVIDENCE: 4 Laryngoscope, 128:2838-2843, 2018.

A tough pill to swallow: Medicolegal liability and dysphagia.

LEVEL OF EVIDENCE: Level 4 (Case Series). OBJECTIVE: Dysphagia is a debilitating condition that is associated with many etiologies. It can have a devastating effect on a patient's quality of life with long-term sequelae that make it a source of medical malpractice litigation. This study analyzed medical malpractice cases involving dysphagia and looked for factors determining legal liability. METHODS: The Westlaw Next legal database (Thomson Reuters, New York, NY) was searched for relevant malpractice cases and assessed for several factors including if the dysphagia was iatrogenic, the amount paid by the defendant, and the medical specialty of the defendants. RESULTS: A total of 45 cases of dysphagia were included. The majority of these cases were jury verdicts for the defendant (73.3%). Iatrogenic dysphagia was alleged in 55.5% of cases. Settlements and verdicts favoring the plaintiff resulted in awards ranging between $25,000 and $5,003,000 with a mean of $1,014,015. The most frequent physician specialists named were general surgeons (24.1), internists (11.1%), anesthesiologists (9.3%), gastroenterologists (7.4%), and otolaryngologists (5.6%). Iatrogenic dysphagia (OR 8.89 CI 1.02-77.32), medication-related iatrogenesis (OR 18.86 CI 1.82-195.41), and cases naming multiple specialties as a defendant (OR 5.90, CI 1.07-32.55) were factors associated with a verdict for the plaintiff or a settlement. CONCLUSION: Dysphagia is a condition with medicolegal consequences for many specialties. While the majority of these cases are decided in favor of the defendant the cost of a negative outcome is considerable. Iatrogenic dysphagia and naming more than one defendant specialty were associated with increased odds of a plaintiff verdict or settlement.

Selective recurrent laryngeal nerve stimulation using a penetrating electrode array in the feline model.

OBJECTIVES/HYPOTHESIS: Laryngeal muscles (LMs) are controlled by the recurrent laryngeal nerve (RLN), injury of which can result in vocal fold (VF) paralysis (VFP). We aimed to introduce a bioelectric approach to selective stimulation of LMs and graded muscle contraction responses. STUDY DESIGN: Acute experiments in cats. METHODS: The study included six anesthetized cats. In four cats, a multichannel penetrating microelectrode array (MEA) was placed into an uninjured RLN. For RLN injury experiments, one cat received a standardized hemostat-crush injury, and one cat received a transection-reapproximation injury 4 months prior to testing. In each experiment, three LMs (thyroarytenoid, posterior cricoarytenoid, and cricothyroid muscles) were monitored with an electromyographic (EMG) nerve integrity monitoring system. Electrical current pulses were delivered to each stimulating channel individually. Elicited EMG voltage outputs were recorded for each muscle. Direct videolaryngoscopy was performed for visualization of VF movement. RESULTS: Stimulation through individual channels led to selective activation of restricted nerve populations, resulting in selective contraction of individual LMs. Increasing current levels resulted in rising EMG voltage responses. Typically, activation of individual muscles was successfully achieved via single placement of the MEA by selection of appropriate stimulation channels. VF abduction was predominantly observed on videolaryngoscopy. Nerve histology confirmed injury in cases of RLN crush and transection experiments. CONCLUSIONS: We demonstrated the ability of a penetrating MEA to selectively stimulate restricted fiber populations within the feline RLN and selectively elicit contractions of discrete LMs in both acute and injury-model experiments, suggesting a potential role for intraneural MEA implantation in VFP management. LEVEL OF EVIDENCE: NA. Laryngoscope, 128:1606-1614, 2018.

Does resident involvement in thyroid surgery lead to increased postoperative complications?

OBJECTIVES/HYPOTHESIS: To evaluate the impact of resident involvement during thyroid surgery on 30-day postoperative complications. STUDY DESIGN: Retrospective cohort study. METHODS: All patients who underwent thyroid surgery in 2011 were identified from the American College of Surgeons National Surgical Quality Improvement Program database. Patient demographics, perioperative details, resident involvement in surgery, and 30-day postoperative complications were extracted. Propensity score analysis was used to match resident and nonresident cases. Univariate and multivariate analysis were performed to determine the relationship between resident involvement in thyroid surgery and postoperative outcomes. RESULTS: One thousand seven hundred forty-seven patients with and 1,747 patients without resident involvement were case-matched for patient demographics, perioperative variables, and surgical case type. There was no significant difference (P = .19) in 30-day postoperative complication rates of surgeries with and without resident involvement, which were 1.4% and 2%, respectively. Operative time was longer in surgeries with residents than those without residents (119 ± 67 minutes vs. 102 ± 55 minutes, P < .001). Cases with resident involvement had an unplanned reoperation rate of 0.9%, which was significantly lower than the 2.3% rate of surgeries without residents (P = .001). Multivariate analysis revealed no significant association between resident involvement and overall complications (odds ratio = 0.70; P = .18). CONCLUSIONS: Resident participation in thyroid surgery was not associated with an increased 30-day postoperative complication rate. These findings demonstrate that patient safety is not adversely affected by resident participation in thyroid surgery. LEVEL OF EVIDENCE: 2C Laryngoscope, 127:1242-1246, 2017.

Laryngeal adenocarcinoma not otherwise specified: A population-based perspective.

OBJECTIVES/HYPOTHESIS: Laryngeal adenocarcinoma not otherwise specified (LAdC NOS) is a category to which variants of minor salivary gland tumors of the larynx that do not fit other well-characterized histological subtypes are assigned. Its rare nature and inconsistency in available reports has hindered the investigation and further understanding of this malignancy. In this study, a national population-based resource was used to evaluate the epidemiology and survival of this rare entity. STUDY DESIGN: Retrospective population-based analysis. METHODS: The Surveillance, Epidemiology, and End Results database was searched for patients diagnosed with LAdC NOS between 1973 and 2012. Patient demographics, tumor location, TNM stage, grade, incidence, and survival trends were collected and analyzed. RESULTS: One hundred eleven patients met criteria for diagnosis of LAdC NOS, of which the majority were male (80.2%), white (84.7%), with a mean age of 65 years. The supraglottis was the most common site at presentation (38.7%). The majority presented with grade II tumor (45.7%). TNM staging revealed T2 (36.8%), N0 (72.2%), and M0 (88.9%) to be the most common classification. The overall incidence between the years of 2000 and 2012 was 0.008/100,000 individuals. The overall 5-year disease-specific survival (DSS) was 60.1%, compared to 85.7% in patients treated with combination surgery and radiotherapy. CONCLUSIONS: LAdC NOS is an uncommon malignancy. It most commonly affects men in their mid-60s, indiscriminate of race. Lesions most commonly present in the supraglottis and are more often low grade histologically. DSS is highest in patient treated with combination surgery and radiotherapy. LEVEL OF EVIDENCE: 4 Laryngoscope, 2016 127:424-429, 2017.

Are Online Zenker's Diverticulum Materials Readable and Understandable?

OBJECTIVE: Patients use a multitude of resources to learn about Zenker's diverticulum (ZD). The objectives of this study were to assess the readability and understandability of online materials on ZD, evaluate them against the existing criteria, and investigate the relationship between readability and understandability. METHODS: The first 50 webpages from an online search for ZD were analyzed. Twenty-one webpages had materials intended for patients and were included in the study. The patient education materials (PEMs) were analyzed using 6 readability tools. Four individuals used the Patient Education Materials Evaluation Tool (PEMAT) to assess the understandability. Fleiss κ interrater reliability analysis determined consistency among the raters. Finally, Pearson correlation coefficient analyzed the relationship between readability and understandability. RESULTS: The reading grade level of the materials reviewed ranged from 10th to 16th grade while the understandability ranged from 31% to 74%. Correlation analysis demonstrated a strong negative correlation between readability and understandability (r = -0.62, P < .05). Fleiss' κ interrater reliability for the raters demonstrated substantial agreement between the 4 raters (κ = 0.64). CONCLUSION: Online PEMs pertaining to ZD are written well above the recommended reading level. Materials written at a lower reading level are more understandable. A wide range of understandability exists among materials with identical reading grade levels. IMPLICATIONS FOR PRACTICE: Health care providers need to create new PEMs for ZD that are available online that are both readable and understandable. The PEMAT and readability formulas can provide a framework for authors to create these materials.

The Utility of Recurrent Laryngeal Nerve Monitoring During Open Pharyngeal Diverticula Procedures.

OBJECTIVES: The recurrent laryngeal nerve is at risk of injury during open pharyngeal diverticula operations. The utility of recurrent laryngeal nerve (RLN) monitoring during these procedures was investigated. METHODS: A retrospective chart review was performed of 8 open pharyngeal diverticulectomies completed between 2009 and 2014. Intraoperative RLN monitoring took place during all operations. RESULTS: Open pharyngectomy and myotomy was successfully performed in all cases. In two cases the RLN was encountered outside of its normal course. The identity of the nerve was confirmed with electrical stimulation and normal EMG response. Vocal fold motion was preserved in all cases. CONCLUSIONS: Use of intraoperative nerve monitoring in pharyngeal diverticula procedures may be beneficial, especially during open operations for Killian-Jamieson diverticulum (KJD) and large Zenker diverticulum (ZD), where the RLN is typically encountered outside of its normal course.

Readability and Understandability of Online Vocal Cord Paralysis Materials.

OBJECTIVE: Patients use several online resources to learn about vocal cord paralysis (VCP). The objective of this study was to assess the readability and understandability of online VCP patient education materials (PEMs), with readability assessments and the Patient Education Materials Evaluation Tool (PEMAT), respectively. The relationship between readability and understandability was then analyzed. STUDY DESIGN AND SETTING: Descriptive and correlational design. METHOD: Online PEMs were identified by performing a Google search with the term "vocal cord paralysis." After scientific webpages, news articles, and information for medical professionals were excluded, 29 articles from the first 50 search results were considered. Readability analysis was performed with 6 formulas. Four individuals with different educational backgrounds conducted understandability analysis with the PEMAT. Fleiss's Kappa interrater reliability analysis determined consistency among raters. Correlation between readability and understandability was determined with Pearson's correlation test. RESULTS: The reading level of the reviewed articles ranged from grades 9 to 17. Understandability ranged from 29% to 82%. Correlation analysis demonstrated a strong negative correlation between materials' readability and understandability (r = -0.462, P < .05). CONCLUSION: Online PEMs pertaining to VCP are written above the recommended reading levels. Overall, materials written at lower grade levels are more understandable. However, articles of identical grade levels had varying levels of understandability. The PEMAT may provide a more critical evaluation of the quality of a PEM when compared with readability formulas. Both readability and understandability should be used to evaluate PEMs.

Evaluation of Heating and Shearing on the Viscoelastic Properties of Calcium Hydroxyapatite Used in Injection Laryngoplasty.

OBJECTIVE: To compare the viscoelastic properties of calcium hydroxyapatite (CaHA) to carboxymethylcellulose (CMC) injectables used for injection laryngoplasty and determine if they are affected by heating and shearing. STUDY DESIGN: Experimental. SETTING: University laboratory. SUBJECTS AND METHODS: Vocal fold injection laryngoplasty with CaHA is oftentimes challenging due to the amount of pressure necessary to push the injectate through a needle. Anecdotal techniques, such as heating the product, have been suggested to facilitate injection. The viscoelastic properties of CaHA and CMC were measured with a rheometer. The effects of heating and shearing on sample viscoelasticity were recorded. RESULTS: CaHA was 9.5 times more viscous than CMC (43,100 vs 4540 Pa·s). Heating temporarily decreased the viscosity of CaHA by 32%. However, it also caused the viscosity to subsequently increase after time. Shearing of CaHA reduced its viscosity by 26%. Heating and shearing together temporarily reduced the viscosity of CaHA by 52%. CONCLUSION: A combination of heating and shearing had a more profound effect than heating or shearing alone on the viscosity of CaHA, potentially making it easier to inject temporarily. Long-term and in vivo studies are required to further analyze the effect of heating and shearing on CaHA injectables.

Soot and house dust mite allergen cause eosinophilic laryngitis in an animal model.

OBJECTIVES/HYPOTHESIS: Chronic laryngitis (CL) is common and costly. One of the most common causes of CL is thought to be laryngopharyngeal reflux, although a significant percentage of individuals fail to get better with acid suppressive therapy. The role of other potential causes of CL such as allergy and environmental pollution has not been thoroughly investigated. PURPOSE: To evaluate the association between iron soot, house dust mite allergen (HDMA), and CL in an established animal model. METHODS: Twenty-four guinea pigs were separated into four 6-week exposure groups: 1) saline (allergen control) + filtered air (pollution control); 2) HDMA (Dermatophygoides farinae) + filtered air; 3) saline + combustion particulates; or 4) HDMA + combustion particulates. The primary outcome measure was mean eosinophil profile (MEP) in glottic, subglottic, and trachea epithelium and submucosa. RESULTS: The combination of iron soot and HDMA caused eosinophilia (elevated MEP) in the glottic (P < 0.06), subglottic (P < 0.05), and trachea (P < 0.05) submucosa and epithelium (P < 0.05). CONCLUSION: The combination of HDMA and iron soot resulted in laryngeal eosinophilia in an established guinea pig model of CL. The data support the notion that factors other than reflux may cause CL. Further investigation into eosinophilic laryngitis as a distinct clinical entity caused by exposure to environmental allergen and pollution is warranted.