Euclidean distances of laryngopharyngeal structures obtained from CT data for preclinical development of laryngoscopic devices

Diers, Daniela; Fast, Jacob Friedemann; Götz, Friedrich; Kahrs, Lüder A.; Miller, S.; Jungheim, M.; Ptok, M.

doi:10.1007/s00276-019-02397-3

Cited by 2 publications

(1 citation statement)

References 17 publications

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“…The targets were consecutively positioned perpendicularly to the laryngoscopic direction of view at a distance of approximately 66 mm and 51 mm for the rod lens-based system and the fiberoptic system, respectively. These values correspond to the expected average distances between the laryngoscope tip and the glottal area [51]. Based on the trajectory approximation T para and the stereoscopic reconstruction of the target, the predicted droplet impact site was calculated and superimposed onto the undistorted and rectified left laryngoscopic image.…”

Section: ) Goodness Of Fit Of Trajectory Modelsmentioning

confidence: 98%

Stereo Laryngoscopic Impact Site Prediction for Droplet-Based Stimulation of the Laryngeal Adductor Reflex

et al. 2021

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The laryngeal adductor reflex (LAR) is a vital reflex of the human larynx. LAR malfunctions may cause life-threatening aspiration events. An objective, noninvasive, and reproducible method for LAR assessment is still lacking. Stimulation of the larynx by droplet impact, termed Microdroplet Impulse Testing of the LAR (MIT-LAR), may remedy this situation. However, droplet instability and imprecise stimulus application thus far prevented MIT-LAR from gaining clinical relevance. We present a system comprising two alternative, custom-built stereo laryngoscopes, each offering a distinct set of properties, a droplet applicator module, and image/point cloud processing algorithms to enable a targeted, dropletbased LAR stimulation. Droplet impact site prediction (ISP) is achieved by droplet trajectory identification and spatial target reconstruction. The reconstruction and ISP accuracies were experimentally evaluated. Global spatial reconstruction errors at the glottal area of (0.3 ± 0.3) mm and (0.4 ± 0.3) mm and global ISP errors of (0.9 ± 0.6) mm and (1.3 ± 0.8) mm were found for a rod lens-based and an alternative, fiberoptic laryngoscope, respectively. In the case of the rod lens-based system, 96 % of all observed ISP error values are inferior to 2 mm; a value of 80 % was found with the fiberoptic assembly. This contribution represents an important step towards introducing a reproducible and objective LAR screening method into the clinical routine.INDEX TERMS Aspiration, biomedical engineering, computer aided diagnosis, endoscopes, image guidance, laryngeal closure reflex, reflex latency, stereo endoscopy.

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Section: ) Goodness Of Fit Of Trajectory Modelsmentioning

confidence: 98%

Stereo Laryngoscopic Impact Site Prediction for Droplet-Based Stimulation of the Laryngeal Adductor Reflex

et al. 2021

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Droplet applicator module for reproducible and controlled endoscopic laryngeal adductor reflex stimulation

et al. 2020

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This work presents a droplet applicator module to generate stable droplets with different muzzle energies for the reproducible endoscopic stimulation of the laryngeal adductor reflex (LAR). The LAR is a protective reflex of the human larynx; an abnormal LAR performance may cause aspiration pneumonia. A pathological LAR can be detected by evaluating its onset latency. The reflex can be triggered by shooting a droplet onto the laryngeal mucosa, which is referred to as Microdroplet Impulse Testing of the LAR (MIT-LAR). Stimulation intensity variation is desired as the reflex threshold may vary inter-individually. The kinetic energy of a droplet after detachment from the nozzle, i.e., its muzzle energy, is considered an appropriate metric for the LAR stimulation intensity. In this work, a suitable nozzle channel geometry is identified based on the experimental evaluation of droplet formation using three different nozzle channel geometries. Two nontoxic additives are evaluated regarding their effect on fluid properties and droplet formation. The range of achievable droplet muzzle energies is determined by high-speed cinematography in association with a physically motivated model of the macroscopic droplet motion. The experimental results show that sodium chloride is a suitable additive to enhance droplet stability in the studied parameter range with the proposed system. Droplet muzzle energy variation from 0.02 μJ to 1.37 μJ was achieved while preserving the formation of a single stimulation droplet. These results are an important prerequisite for a safe and reproducible LAR stimulation by MIT-LAR, which could also help to further elucidate the physiological mechanisms underlying this laryngeal reflex.

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Euclidean distances of laryngopharyngeal structures obtained from CT data for preclinical development of laryngoscopic devices

Cited by 2 publications

References 17 publications

Stereo Laryngoscopic Impact Site Prediction for Droplet-Based Stimulation of the Laryngeal Adductor Reflex

Stereo Laryngoscopic Impact Site Prediction for Droplet-Based Stimulation of the Laryngeal Adductor Reflex

Droplet applicator module for reproducible and controlled endoscopic laryngeal adductor reflex stimulation

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