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Objective(s): To create and validate a synthetic simulator for teaching tracheostomy and laryngotracheal reconstruction (LTR) using anterior costal cartilage and thyroid ala cartilage grafts. Methods: A late adolescent/adult neck and airway simulator was constructed based on CT scans from a cadaver and a live patient. Images were segmented to create three‐dimensional printed molds from which anatomical parts were casted. To evaluate the simulator, expert otolaryngologists ‐ head and neck surgeons performed tracheostomy and LTR using anterior costal cartilage and thyroid ala cartilage grafts on a live anesthetized porcine model (gold standard) followed by the synthetic simulator. They evaluated each model for face validity (realism and anatomical accuracy) and content validity (perceived effectiveness as a training tool) using a five‐point Likert scale. For each expert, differences for each item on each simulator were compared using Wilcoxon Signed‐Rank tests with Sidak correction. Results: Nine expert faculty surgeons completed the study. Experts rated face and content validity of the synthetic simulator an overall median of 4 and 5, respectively. There was no difference in scores between the synthetic model and the live porcine model for any of the steps of any of the surgical procedures. Conclusion: The synthetic simulator created for this study has high face and content validity for tracheostomy and LTR with anterior costal cartilage and thyroid ala cartilage grafts and was not found to be different than the live porcine model for these procedures. Level of Evidence: 5 Laryngoscope, 131:E2378–E2386, 2021 [ABSTRACT FROM AUTHOR]

Objectives/hypothesis: To evaluate the validity of a live porcine model for surgical training in tracheostomy and open-airway surgery.Study Design: Prospective observational study.Methods: Eleven expert otolaryngologists-head and neck surgeons rated a live porcine model's realism/anatomical accuracy (face validity) and perceived effectiveness as a training tool (content validity) for tracheostomy and laryngotracheoplasty using anterior costal cartilage and thyroid ala cartilage grafts using a 53-item post-trial questionnaire with a five-point Likert scale.Results: Experts rated the face validity of the live porcine model a median (interquartile range [IQR]) of 4/5 (4-5) and the content validity a median (IQR) of 5/5 (4-5) for each surgical procedure. Overall, 91% strongly agreed or agreed that the simulator would increase trainee competency for tracheostomy and laryngotracheoplasty using costal cartilage graft, and 82% strongly agreed or agreed that it would increase trainee competency for laryngotracheoplasty using thyroid ala cartilage graft.Conclusions: The live porcine model has high face and content validity as a training tool for tracheostomy and laryngotracheoplasty using costal cartilage and thyroid ala cartilage grafts. This training model can help surgical trainees practice these complex, low-frequency procedures.Level Of Evidence: NA Laryngoscope, 130: 2063-2068, 2020. [ABSTRACT FROM AUTHOR]

Background: Ischemia-reperfusion (I/R) injury involves damage to the microvessel structure (eg, increased permeability) and function (blunted vasomodulation). While microstructural damage can be detected with dynamic contrast-enhanced (DCE) MRI, there is no diagnostic to detect deficits in microvascular function.Purpose: To apply a novel MRI method for evaluating dynamic vasomodulation to assess microvascular dysfunction in skeletal muscle following I/R injury.Study Type: Prospective, longitudinal.Animal Model: Twenty-three healthy male adult Sprague-Dawley rats.Field Strength/sequence: Dynamic T1 fast field echo imaging at 3.0T with preinjection T1 mapping.Assessment: Injury in the left hindlimb was induced using a 3-hour I/R procedure. Longitudinal MRI scanning was performed up to 74 days, with animals completing assessment at different intervals for histological and laser Doppler perfusion validation. Pharmacokinetic parameters Ktrans and ve were determined following i.v. injection of gadovist (0.1 mmol/kg). Vasomodulatory response was probed on gadofosveset (0.3 mmol/kg) using hypercapnic gases delivered through a controlled gas-mixing circuit to induce vasoconstriction and vasodilation in ventilated rats. Heart rate and blood oxygen saturation were monitored.Statistical Tests: Two-way analysis of variance with Tukey-Kramer post-hoc analysis was used to determine significant changes in vasomodulatory response, Ktrans , and ve .Results: This new MRI technique revealed impaired vasomodulation in the injured hindlimb. Vasoconstriction was maintained, but vasodilation was blunted up to 21 days postinjury (P < 0.05). However, DCE-MRI measured Ktrans and ve were significantly (P < 0.05) different from baseline only during acute inflammation (Day 3), with severe inflammation noted on histology.Data Conclusion: While conventional DCE-MRI shows normalization after the acute phase, our new approach reveals sustained functional impairment in muscle microvasculature following I/R injury, with compromised response in vasomotor tone present for at least 21 days.Level Of Evidence: 4 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:1174-1185. [ABSTRACT FROM AUTHOR]

Purpose: To characterize T2* and T1 relaxation time response to a wide spectrum of gas challenges in extracranial tissues of healthy rats.Materials and Methods: A range of graded gas mixtures (hyperoxia, hypercapnia, hypoxia, and hypercapnic hypoxia) were delivered through a controlled gas-mixing circuit to mechanically ventilated and intubated rats. Quantitative magnetic resonance imaging (MRI) was performed on a 3T clinical scanner; T2* and T1 maps were computed to determine tissue response in the liver, kidney cortex, and paraspinal muscles. Heart rate and blood oxygen saturation (SaO2 ) were measured through a rodent oximeter and physiological monitor.Results: T2* decreases consistent with lowered SaO2 measurements were observed for hypercapnia and hypoxia, but decreases were significant only in liver and kidney cortex (P < 0.05) for >10% CO2 and <15% O2 , with the new gas stimulus, hypercapnic hypoxia, producing the greatest T2* decrease. Hyperoxia-related T2* increases were accompanied by negligible increases in SaO2 . T1 generally increased, if at all, in the liver and decreased in the kidney. Significance was observed (P < 0.05) only in kidney for >90% O2 and >5% CO2 .Conclusion: T2* and T1 provide complementary roles for evaluating extracranial tissue response to a broad range of gas challenges. Based on both measured and known physiological responses, our results are consistent with T2* as a sensitive marker of blood oxygen saturation and T1 as a weak marker of blood volume changes. J. Magn. Reson. Imaging 2016;44:305-316. [ABSTRACT FROM AUTHOR]