Synthesis and Evaluation of a Novel PET Radioligand for Imaging Glutaminyl Cyclase Activity as a Biomarker for Detecting Alzheimer's Disease.

Several new lines of research have demonstrated that a significant number of amyloid-ß peptides found in Alzheimer's disease (AD) are truncated and undergo post-translational modification by glutaminyl cyclase (QC) at the N-terminal. Notably, QC's products of Abeta-pE3 and Abeta-pE11 have been active targets for investigational drug development. This work describes the design, synthesis, characterization, and in vivo validation of a novel PET radioligand, [18F]PB0822, for targeted imaging of QC. We report herein a simplified and robust chemistry for the synthesis of the standard compound, [19F]PB0822, and the corresponding [18F]PB0822 radioligand. The PET probe was developed with 99.9% radiochemical purity, a molar activity of 965 Ci.mmol-1, and an IC50 of 56.3 nM, comparable to those of the parent PQ912 inhibitor (62.5 nM). Noninvasive PET imaging showed that the probe is distributed in the brain 5 min after intravenous injection. Further, in vivo PET imaging with [18F]PB0822 revealed that AD 5XFAD mice harbor significantly higher QC activity than WT counterparts. The data also suggested that QC activity is found across different brain regions of the tested animals.

Outcomes for COVID-19 Patients Undergoing Tracheostomy With or Without Extracorporeal Membrane Oxygenation (ECMO).

Introduction The coronavirus disease 2019 (COVID-19) pandemic led to the more common use of venovenous (VV) extracorporeal membrane oxygenation (ECMO) for adults with acute respiratory distress syndrome (ARDS). While tracheostomy is generally understood to decrease the risks of prolonged endotracheal intubation, there is conflicting data regarding the benefit of tracheostomy in patients on ECMO. The purpose of this study is to determine whether ECMO cannulation before tracheostomy impacted patient outcomes. Methods This is a retrospective chart review of patients who underwent tracheostomy for COVID-19-related ARDS at a tertiary academic center from March 2020 through March 2022. Patients were separated into two groups based on whether they were cannulated for ECMO prior to tracheostomy. Fisher's exact test or Wilcoxon rank sum test was used to compare the two groups. Results A total of 24 patients were included in the study, with 13 in the ECMO group and 11 in the non-ECMO group. There was no significant difference in age, comorbidities, race, or gender between the groups. Patients on ECMO had a longer time from admission to intubation (seven days vs. three days, p=.002), were more likely to have multiple intubations (54% vs 9%, p= .033), had increased rates of postoperative bleeding (62% vs. 18%, p = .047), and had a higher mortality rate (39% vs. 0%, p= .041). Conclusions ECMO cannulation prior to tracheostomy for COVID-19-related ARDS is associated with poorer outcomes. It is unclear whether this is related to a more severe disease burden in these patients. Further study is needed to evaluate this and guide future management.

Clinical Voice Outcomes for Two Voice Rest Protocols after Phonomicrosurgery.

OBJECTIVES: Voice rest is commonly recommended for patients with benign vocal fold lesions (BVFLs) after phonomicrosurgery. The study compares the clinical voice outcomes of two protocols, 7-day complete voice rest (CVR) and 3-day CVR followed by 4-day relative voice rest (CVR + RVR), for patients with BVFLs after phonomicrosurgery. STUDY DESIGN: Prospective, randomized controlled trial. METHOD: Patients with BVFLs undergoing phonomicrosurgery were recruited prospectively and randomly assigned to either protocol. Outcomes were assessed on objective measures of acoustics (fundamental frequency, frequency range, mean intensity, cepstral peak analysis) and aerodynamics (vital capacity, airflow rate, subglottal pressure, phonation threshold pressure), as well as subjective measures, both provider-reported through the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V), and patient-reported through the Voice Handicap Index (VHI). Clinical measures were collected at three-time points: preoperatively, 1-week postoperatively (on voice rest), and 1-month postoperatively. In addition, adherence was estimated using a vocal dosimeter. RESULTS: Twenty-five patients were recruited and randomized to 7-day CVR (n = 13) and CVR + RVR regimen (n = 12). Statistically significant changes were found within both groups for subglottal pressure (p = 0.03) and VHI score (p < 0.001) comparing pre-operative baseline to 1-month postoperative follow-up. There were no statistically significant differences between the groups. Regardless of group assignment, a significant decrease in overall severity ratings for the CAPE-V was found by comparing the preoperative scores to postoperative scores at 1-week (p < 0.001) and 1-month (p < 0.001). CONCLUSION: Both groups improved their overall voice quality comparably 1 month after undergoing phonomicrosurgery as measured by objective and subjective parameters. LEVELS OF EVIDENCE: 2. Laryngoscope, 134:2812-2818, 2024.

Postnasal drip and chronic cough in patients with chronic rhinitis treated with temperature-controlled radiofrequency neurolysis.

OBJECTIVE: To evaluate the contribution of postnasal drip (PND) and chronic cough (CC) to symptoms of patients with chronic rhinitis treated with temperature-controlled radiofrequency (TCRF) neurolysis of the posterior nasal nerve (PNN), and correlate PND and CC scores with components of the reflective total nasal symptom score (rTNSS). METHODS: Pooled data from three prospective studies: two single-arm studies and the index active treatment arm of a randomized controlled trial. Adult patients with baseline rTNSS ≥6 were treated with TCRF neurolysis at nonoverlapping regions of the PNN. PND and CC symptoms were evaluated on a 0 (none) to 3 (severe) scale. RESULTS: Data from 228 patients (57.9% women, 42.1% men) were included. The mean baseline rTNSS was 8.1 (95% confidence interval [CI], 7.8-8.3), which decreased to 3.2 (95% CI, 2.9-3.5) at 6 months. At baseline, 97.4% of patients had PND and 80.3% had CC. Median baseline PND and CC symptom scores were 3 (interquartile range [IQR], 2-3) and 2 (IQR, 1-2), respectively. At 6 months, this decreased to 1 (IQR, 0-2) and 0 (IQR, 0-1), respectively, showing significant improvement from baseline (both p < 0.001). Spearman correlation coefficients with components of rTNSS (rhinorrhea, congestion, itching, sneezing) were 0.16 to 0.22 for CC and 0.19 to 0.46 for PND, indicating only a weak to moderate correlation. CONCLUSION: PND and CC contribute to the symptomatology of chronic rhinitis and are significantly improved after TCRF neurolysis of the PNN. The inclusion of PND and CC symptoms in a chronic rhinitis assessment instrument could provide important additional information for the characterization of the disease state and outcomes after any therapeutic treatment.

Fully automated dual-run manufacturing of [11C]PIB on FASTlab.

This report describes an updated, fully automated method for the production of [11C]PIB on a cassette-based automated synthesis module. The method allows for two separate productions of [11C]PIB, both of which meet all specification for use in clinical studies. The GE FASTlab developer system was used to create the cassette design as well as the controlling tracer package. The method takes 16 min from the delivery of [11C]MeOTf to the FASTlab, or 35 min from the End of Bombardment; and reliably produces 3547 ± 586 MBq of [11C]PIB in high radiochemical purity (> 98 %). This methodology increases the production capacity of radiopharmaceutical facilities for [11C]PIB, and can easily produce 4 batches in a single day with limited infrastructure footprint.

Fully automated radiosynthesis of [68Ga]Ga-FAPI-46 with cyclotron produced gallium.

BACKGROUND: Radiopharmaceuticals capable of targeting the fibroblast activation protein have become widely utilized in the research realm as well as show great promise to be commercialized; with [68Ga]Ga-FAPI-46 being one of the most widely utilized. Until now the synthesis has relied on generator-produced gallium-68. Here we present a developed method to utilize liquid-target cyclotron-produced gallium-68 to prepare [68Ga]Ga-FAPI-46. RESULTS: A fully-automated manufacturing process for [68Ga]Ga-FAPI-46 was developed starting with the 68Zn[p,n]68Ga cyclotron bombardment to provide [68Ga]GaCl3, automated purification of the [68Ga]GaCl3, chelation with the precursor, and final formulation/purification. The activity levels produced were sufficient for multiple clinical research doses, and the final product met all release criteria. Furthermore, the process consistently provides < 2% of Ga-66 and Ga-67 at the 4-h expiry, meeting the Ph. Eur. CONCLUSIONS: The automated radiosynthesis on the GE FASTlab 2 module purifies the cyclotron output into [68Ga]GaCl3, performs the labeling, formulates the product, and sterilizes the product while transferring to the final vial. Production of > 40 mCi (> 1480 MBq) of [68Ga]Ga-FAPI-46 in excellent radiochemical yield was achieved with all batches meeting release criteria.

One-year follow-up of hospital nurses' work experiences during the COVID-19 pandemic: A qualitative study.

AIM: To follow up on the experiences of Registered Nurses (RNs) working after 1 year of the COVID-19 pandemic in Canadian and American hospitals. DESIGN: Semi-structured interviews were conducted, and transcripts were analysed through a reflexive thematic analysis (RTA). METHODS: RNs (n = 19) first interviewed in the spring of 2020 were re-interviewed 1 year after their original interviews (May 25, 2021-June 25, 2021). Participants consisted of nurses residing in Canada and working in Ontario (n = 12) or American hospitals (n = 7), i.e., both local and cross-border nurses. RESULTS: Five themes were identified: (1) "You call us heroes, but you forgot us": Nurses described experiences of disrespect and stigma from their communities, their government, and their workplaces. (2) "A whole new level of busy": Nurses reported stressors both at home and at work that had increased exponentially throughout the pandemic. (3) "Running on empty": Nurses described burnout and mental health struggles including depression, irritation, and suicidal ideation; they coped using both adaptive and maladaptive strategies. (4) "The job of nursing is painful": Ongoing pandemic issues led nurses to re-evaluate their commitments to their units, their hospitals and the profession itself. (5) "Surviving an un-survivable day": Nurses shared positive moments at work and home that helped give them the strength to carry on. CONCLUSION: Significant investments will be required from hospital organizations and governments to ensure that healthcare systems continue to function safely for patients, their families and nurses. IMPACT: The purpose of this study was to understand and describe nurses' experiences after 1 year of working during the COVID-19 pandemic. Nurses reported feeling disrespected, overwhelmed, and burned out; many were looking to leave the profession. These findings will be of interest to nurses working on the frontline of the pandemic as well as hospital managers and policy makers. NO PATIENT OR PUBLIC CONTRIBUTION: In this investigation, nurses were the participants.

Exploring Personality and Perceived Present Control as Factors in Postsurgical Voice Rest: A Case Comparison.

OBJECTIVE: This case comparison explored the relation between personality, perceived present control, and postoperative voice rest (as estimated by self-report and objective voice use) following surgery for benign vocal fold lesions. METHOD: Two participants were included. Both participants were diagnosed with benign vocal fold pathology, underwent phonosurgery, and were assigned to either complete voice rest (CVR) or relative voice rest (RVR) postoperatively. During voice rest (VR), a visual analog scale (VAS) and a dosimeter (the Vocalog2) were used daily to estimate self-perceived and objective voice use, respectively. The participants also completed questionnaires on voice-related demographics, the Voice Handicap Index (VHI), Ten-Item Personality Inventory (TIPI), and Perceived Present Control (PPC). After 7 days of CVR or RVR, participants completed a postoperative questionnaire and a final VAS for overall voice use. RESULTS: A wide discrepancy was observed in one of two participant's subjective perception of voice use (using the VAS) versus objective dosimetry data wherein she reported significantly more voice use than was observed objectively. Differences in personality and PPC between the participants did not appear to affect their voice use following the VR protocols. CONCLUSION: The amount of voice use in both VR protocols for these two participants suggests that personality and PPC did not affect their adherence to recommendations of VR. Patients may perceive their voice use differently across time, which might play a role in their adherence to voice rest recommendations: voice use measured as instances versus a unit of time (seconds).

"I Called us the Sacrificial Lambs": Experiences of Nurses Working in Border City Hospitals During the First Wave of the COVID-19 Pandemic.

BACKGROUND: The first wave of the COVID-19 pandemic had a significant impact on the personal and professional lives of frontline nurses. PURPOSE: The purpose of this descriptive phenomenological study was to explore the experiences of Canadian Registered Nurses (RNs) working in Ontario or United States hospitals during the first wave of the COVID-19 pandemic. METHODS: Semi-structured interviews were conducted with 36 RNs living in Ontario and employed either at an Ontario or United States hospital. Three main themes were identified across both healthcare contexts. RESULTS: 1) The Initial Response to the pandemic included a rapid onset of chaos and confusion, with significant changes in structure and patient care, often exacerbated by hospital management. Ethical concerns arose (e.g., redeployment, allocation of resources) and participants described negative emotional reactions. 2) Nurses described Managing the Pandemic by finding new ways to nurse and enhanced teamwork/camaraderie; they reported both struggle and resiliency while trying to maintain work and home life balance. Community responses were met with both appreciation and stigma. 3) Participants said they were Looking Forward to a "new normal", taking pride in patient improvements, accomplishments, and silver linings, with tempered optimism about the future. Many expressed a reaffirmation of their identities as nurses. Differences between participants working in the US and those working in Ontario were noted in several areas (e.g., initial levels of chaos, ethical concerns, community stigma). CONCLUSIONS: The COVID-19 pandemic has been very difficult for nursing as a profession. Close attention to post-pandemic issues is warranted.

Automated synthesis of (R)-[18 F]MH.MZ on the iPhase Flexlab reaction platform.

(R)-[18 F]MH.MZ ([18 F]MH.MZ) is a promising positron emission tomography (PET) radiotracer for in vivo study of the 5-HT2A receptor. To facilitate clinical trials, a fully automated radiosynthesis procedure for [18 F]MH.MZ was developed using commercially available materials on the iPhase Flexlab module. The overall synthesis time was 100 min with a radiochemical yield of 7 ± 0.9% (n = 3). The radiochemical purity was greater than 99% for [18 F]MH.MZ with a molar activity of 361 ± 57 GBq/µmol (n = 3). The protocol described herein reliably provides [18 F]MH.MZ that meets all relevant release criteria for a GMP radiopharmaceutical.

Validation of the Communicative Participation Item Bank as an Outcome Measure for Spasmodic Dysphonia.

OBJECTIVES: Current patient-reported outcome measures do not adequately capture the impact of spasmodic dysphonia (SD) on communication in daily life situations. The aim of this study was to validate the Communicative Participation Item Bank (CPIB), which specifically measures a disease's impact on daily conversational situations, as an outcome measure for SD. STUDY DESIGN: Multi-institutional prospective cohort study. METHODS: A prospective study was conducted with administration of the 46-question CPIB and the Voice Handicap Index-10 (VHI-10) to 190 participants with SD before (time 1) and 6 weeks after (time 2) botulinum toxin injection. Differential item function (DIF) analyses were performed to examine potential item bias. Paired t-tests were used to assess change in each of the CPIB and VHI-10 scores after treatment. Pearson correlations were calculated between the CPIB and VHI-10. RESULTS: DIF analyses revealed no clinically meaningful difference between the item parameters generated for this SD sample and the original CPIB calibration sample. There were statistically significant changes between the pre-treatment and post-treatment time points for both the CPIB and VHI-10. Correlations between the CPIB and VHI were moderate-high. CONCLUSIONS: The CPIB item bank, General Short Form, and scoring parameters can be used with people with SD for valid and reliable measurement of the impact of communication disorders on communication in everyday life. The CPIB is sensitive to changes with intervention, proving useful for clinical and research purposes to assess the efficacy and effectiveness of interventions. LEVEL OF EVIDENCE: Level 2, prospective observational research with an experimental design (ie, cohort study). Laryngoscope, 131:859-864, 2021.

Relationship of vocal fold atrophy to swallowing safety and cough function in Parkinson's disease.

OBJECTIVES: When swallowing function is compromised in patients with Parkinson's disease (PD), cough plays a crucial role in clearing the airway and preventing pulmonary complications. The aim of this study was to determine the influence of vocal fold atrophy severity as measured by the bowing index (BI) on airway protection in PD. METHODS: Thirty participants with PD completed measures of voluntary and reflex cough. Flexible laryngoscopy with endoscopic evaluation of swallowing allowed for measurement of BI using ImageJ software. Swallowing safety was scored on the Penetration-Aspiration Scale (PAS). Regression and receiver operating characteristic (ROC) analyses were performed to test our study aim. RESULTS: Twenty-four of 30 participants had some degree of vocal fold atrophy (BI >0). When controlling for age, disease duration did not significantly influence BI. BI was not predictive of any sensorimotor parameters of cough including measures of cough airflow, reflex cough threshold, or urge to cough. BI discriminated participants with near-normal (PAS 1-3) swallowing safety from participants with impaired (PAS 4-8) swallowing safety (P = .01, sensitivity: 87.0%, specificity: 71.4%, cutoff value BI >4.6). CONCLUSION: Vocal fold atrophy is a potential factor contributing to poor swallowing safety in PD. BI was not associated with cough function in this PD cohort, contrary to prior studies that have shown improved cough measures after vocal fold augmentation. Vocal fold atrophy in PD remains an important area of study as a targetable intervention for patients with airway protective dysfunction. Future studies should include measures of glottic closure during vocal fold adduction. LEVEL OF EVIDENCE: Level 3 Laryngoscope, 130:303-308, 2020.

The effect of large amplitude vibration on the pressure-dependent absorption of a structure multiple cavity system.

This study addresses the effects of large-amplitude vibration on the pressure-dependent absorption of a structure multiple-cavity system. It is the first study to consider the effects of large-amplitude vibration and pressure-dependent absorption. Previous studies considered only one of these two factors in the absorption calculation of a perforated panel absorber. Nonlinear differential equations, which represent the structural vibration of a perforated panel absorber, are coupled with the wave equation, which represents the acoustic pressures induced within the cavities. The coupled nonlinear differential equations are solved with the proposed harmonic balance method, which has recently been adopted to solve nonlinear beam problems and other nonlinear structural-acoustic problems. Its main advantage is that when compared with the classical harmonic balance method, the proposed method generates fewer nonlinear algebraic equations during the solution process. In addition, the solution form of the nonlinear differential equations from this classical method can be expressed in terms of a set of symbolic parameters with various physical meanings. If a numerical method is used, there is no analytic solution form, and the final solution is a set of numerical values. The effects of the excitation magnitude, cavity depth, perforation ratio, and hole diameter on the sound absorption of a panel absorber are investigated, and mode and solution convergence studies are also performed. The solutions from the proposed harmonic balance method and a numerical integration method are compared. The numerical results show that the present harmonic balance solutions agree reasonably well with those obtained with the numerical integration method. Several important observations can be made. First, perforation nonlinearity is a very important factor in the absorption of a panel absorber at the off structural resonant frequency range. The settings of the hole diameter, perforation ratio, and cavity depth for optimal absorption differ greatly with consideration of perforation nonlinearity. Second, the "jump up phenomenon," which does not occur in the case of linear perforation, is observed when perforation nonlinearity is considered. Third, one or more absorption troughs, which worsen the average absorption performance, may exist in cases with multiple cavities.

Implementation of Routine HPV Vaccination in the Management of Recurrent Respiratory Papillomatosis.

OBJECTIVES:: To investigate vaccine compliance and clinical outcomes after implementation of an initiative to provide the human papillomavirus (HPV) vaccine to all patients with recurrent respiratory papillomatosis (RRP). METHODS:: A retrospective review was performed of all adult patients treated for RRP from 2012 to 2017. Rates of HPV vaccination were evaluated before and after December 2015, when a program was established to increase compliance by educating patients and providing financial assistance toward vaccine administration. Paired sample analyses were conducted to compare intersurgical intervals (ISIs) and number of procedures per year pre- and post-vaccination. RESULTS:: Fourteen patients with RRP completed the HPV vaccine series, with 11 patients undergoing vaccination after the initiative began. The pre-initiative vaccination rate of all patients with RRP was 9.7%; post-initiative rates improved to 43.8% ( P = .004; odds ratio, 7.26). Of vaccinated patients, there were significant differences between mean pre-vaccine ISI (3.5 months) and post-vaccine ISI (12.8 months; P = .0021), as well as between number of surgical procedures performed per year before and after vaccination (2.7 vs 0.81; P = .014). After vaccination, 5 patients demonstrated no evidence of papilloma regrowth for >12 months. CONCLUSIONS:: Initiatives focused on patient education and financial support can successfully boost HPV vaccination rates in an RRP patient cohort. Our research mirrors prior findings that HPV vaccination is correlated with an increase in time between procedures and a decrease in number of procedures needed per year-factors that can dramatically reduce the disease burden on patients coping with RRP.

Shar Pei Larynx: Supraglottic and Postcricoid Mucosal Redundancy and Its Association With Medical Comorbidities.

OBJECTIVES:: The aim of this study is to describe a clinical entity the authors term "Shar Pei larynx," characterized by redundant supraglottic and postcricoid mucosa that the authors hypothesize coexists in patients with obstructive sleep apnea, laryngopharyngeal reflux, and obesity. By exploring this hypothesis, the authors hope to set the foundation for future research with the goal of identifying whether Shar Pei larynx is a marker for untreated sleep apnea or other diseases. STUDY DESIGN:: Retrospective chart review. SETTING:: Two tertiary care academic institutions. METHODS:: Data were collected from a 5-year period by querying for patients described to have "Shar Pei larynx" or "posterior supraglottic and/or postcricoid mucosal redundancy" on laryngoscopic findings. Relevant demographic and clinical characteristics were analyzed, with a focus on associations with obesity, sleep apnea, and laryngopharyngeal reflux. RESULTS:: Thirty-two patients were identified with physical findings consistent with Shar Pei larynx. Twenty-six patients (81.3%) were obese; 16 (50%) were morbidly obese. Twenty-two patients (68.8%) either had an existing diagnosis of obstructive sleep apnea or were diagnosed on polysomnography performed after initial evaluation. Sixteen patients (50%) had type 2 diabetes mellitus, and 87.5% of these patients were obese. Twenty-eight patients (87.5%) noted histories of reflux, with a median reflux symptom index of 27 of 45. Five patients underwent procedures to reduce mucosal redundancy related to Shar Pei larynx. CONCLUSIONS:: This pilot study confirms that the majority of patients diagnosed with Shar Pei larynx also had diagnoses of obesity, obstructive sleep apnea, and reflux disease. The demonstrated association is strong enough to warrant further study.

Risk Factors for Posttracheostomy Tracheal Stenosis.

Objective To determine the incidence of posttracheostomy tracheal stenosis and to investigate variables related to the patient, hospitalization, or operation that may affect stenosis rates. Study Design A combined retrospective cohort and case-control study. Setting Tertiary care academic medical center. Subjects and Methods A total of 1656 patients who underwent tracheostomy at a tertiary care medical center from January 2011 to November 2016 were reviewed for evidence of subsequent tracheal stenosis on airway endoscopy or computed tomography. Forty-three confirmed cases of posttracheostomy tracheal stenosis (PTTS) were compared with a subgroup of 319 controls. Factors including medical comorbidity, type and setting of tracheostomy, and hospitalization details were analyzed. Results Five-year incidence of PTTS was 2.6%. Obesity was the sole demographic factor associated with stenosis. Hospitalization-related variables associated with stenosis included tracheostomy after 10 days of orotracheal intubation and endotracheal tube cuff pressure ≥30 mm H2O. The surgical variables associated with higher rates of stenosis included percutaneous technique and insertion of an initial tracheostomy tube size >6. Bjork flap creation was negatively associated with stenosis. In multivariable analysis, obesity and insertion of tracheostomy tube size >6 were identified as risk factors. Conclusion Greater than 10 days of orotracheal intubation prior to tracheostomy and endotracheal tube cuff pressure ≥30 mm H2O were associated with greater rates of subsequent tracheal stenosis. The only patient-related factor associated with tracheal stenosis was obesity. Surgical variables associated with increased rates of subsequent stenosis included placement of a tracheostomy tube size >6, use of percutaneous technique, and failure to create a Bjork flap.

Nonlinear structure-extended cavity interaction simulation using a new version of harmonic balance method.

This study addresses the nonlinear structure-extended cavity interaction simulation using a new version of the multilevel residue harmonic balance method. This method has only been adopted once to solve a nonlinear beam problem. This is the first study to use this method to solve a nonlinear structural acoustic problem. This study has two focuses: 1) the new version of the multilevel residue harmonic balance method can generate the higher-level nonlinear solutions ignored in the previous version and 2) the effect of the extended cavity, which has not been considered in previous studies, is examined. The cavity length of a panel-cavity system is sometimes longer than the panel length. However, many studies have adopted a model in which the cavity length is equal to the panel length. The effects of excitation magnitude, cavity depth, damping and number of structural modes on sound and vibration responses are investigated for various panel cases. In the simulations, the present harmonic balance solutions agree reasonably well with those obtained from the classical harmonic balance method. There are two important findings. First, the nonlinearity of a structural acoustic system highly depends on the cavity size. If the cavity size is smaller, the nonlinearity is higher. A large cavity volume implies a low stiffness or small acoustic pressure transmitted from the source panel to the nonlinear panel. In other words, the additional volume in an extended cavity affects the nonlinearity, sound and vibration responses of a structural acoustic system. Second, if an acoustic resonance couples with a structural resonance, nonlinearity is amplified and thus the insertion loss is adversely affected.

Multicenter Assessment of Antibiotic Prophylaxis Spectrum on Surgical Infections in Head and Neck Cancer Microvascular Reconstruction.

Objective To characterize and identify risk factors for 30-day surgical site infections (SSIs) in patients with head and neck cancer who underwent microvascular reconstruction. Study Design Cross-sectional study with nested case-control design. Setting Nine American tertiary care centers. Subjects and Methods Hospitalized patients were included if they underwent head and neck cancer microvascular reconstruction from January 2003 to March 2016. Cases were defined as patients who developed 30-day SSI; controls were patients without SSI at 30 days. Postoperative antibiotic prophylaxis (POABP) regimens were categorized by Gram-negative (GN) spectrum: no GN coverage, enteric GN coverage, and enteric with antipseudomonal GN coverage. All POABP regimens retained activity against anaerobes and Gram-positive bacteria. Thirty-day prevalence of and risk factors for SSI were evaluated. Results A total of 1307 patients were included. Thirty-day SSI occurred in 189 (15%) patients; median time to SSI was 11.5 days (interquartile range, 7-17). Organisms were isolated in 59% of SSI; methicillin-resistant Staphylococcus aureus (6%) and Pseudomonas aeruginosa (9%) were uncommon. A total of 1003 (77%) patients had POABP data: no GN (17%), enteric GN (52%), and antipseudomonal GN (31%). Variables independently associated with 30-day SSI were as follows: female sex (adjusted odds ratio [aOR], 1.6; 95% CI, 1.1-2.2), no GN POABP (aOR, 2.2; 95% CI, 1.5-3.3), and surgical duration ≥11.8 hours (aOR, 1.9; 95% CI, 1.3-2.7). Longer POABP durations (≥6 days) or antipseudomonal POABP had no association with SSI. Conclusions POABP without GN coverage was significantly associated with SSI and should be avoided. Antipseudomonal POABP or longer prophylaxis durations (≥6 days) were not protective against SSI. Antimicrobial stewardship interventions should be made to limit unnecessary antibiotic exposures, prevent the emergence of resistant organisms, and improve patient outcomes.

Novel approach to maxillary reconstruction using osteocutaneous free tissue transfer with a customized stent.

BACKGROUND: Computer-guided 3D virtual planning and customized templates are novel and effective methods aiding maxillary reconstruction, particularly during osteocutaneous free tissue transfer of complex defects. However, virtual planning and modelling is often expensive. METHODS: We present a new method to reconstruct complex defects with a surgical stent designed from presurgical casts. We present 2 patients who underwent this technique. Reconstruction in both cases was aided by a surgical stent fashioned preoperatively to approximate the anatomic dimensions of the defect, guiding the shape and orientation of the flap during inset to aid in dental rehabilitation. RESULTS: Surgery was performed without evidence of malocclusion, oronasal separation, or osteoradionecrosis with both patients undergoing successful rehabilitation and showing good postoperative oral intake. CONCLUSION: Utilization of our novel surgical stent allowed reconstruction of complex maxillectomy defects and facilitated the design of a reconstructive flap without the need of pre-bent plates, cutting guides, or associated expenses.