Clinical Techniques and Technology Endoscopic Multipoint Laser System for Objective Pediatric Airway Assessment Otolaryngology– Head and Neck Surgery 1–3 Ó American Academy of Otolaryngology–Head and Neck Surgery Foundation 2020 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/0194599820966302 http://otojournal.org Andrew Christopher Hall, FRCS 1 , Annakan Victor Navaratnam, FRCS 1 , Elizabeth Maughan, PhD 1,2 , Benjamin Hartley, FRCS 1 , Richard J. Hewitt, FRCS 1 , and Colin Butler, PhD, FRCS 1,2 Abstract Recent technological advances within aeronautical engineer- ing have demonstrated the delivery of objective quantitative endoscopic measurements to within one-hundredth of a millimeter. We sought to validate this emerging laser tech- nology in a simulation-based assessment of pediatric airway stenosis. A 4.4-mm flexible endoscope, incorporating a laser measurement system projecting 49 laser points into the endoscopic view, was used to assess a simulated model of subglottic stenosis. Multiple anteroposterior and lateral mea- surements were obtained for each stenosis and compared with standard airway assessment techniques. Intra- and inter- observer reliability was assessed. A total of 240 multipoint laser measurements were obtained of simulated airway ste- nosis. The mean difference from manual measurement was 0.1886 mm. The Bland-Altman plot showed low bias (0.011) and narrow 95% limits of agreement (20.46 to 0.48). This advanced endoscopic measurement technique shows great promise for clinical development to benefit ongoing assess- ment and treatment of evolving pediatric airway stenosis. Keywords pediatric airway, subglottic stenosis, endoscopic airway surgery Received May 13, 2020; accepted September 24, 2020. O ptimal management of pediatric airway pathology requires integration of both subjective and objective parameters of assessment. Clinical history and exami- nation remain paramount, yet obtaining objective data allows for the direct comparison of surgical techniques, enables out- come monitoring, and minimizes potential interpretation bias. The internationally recommended standard for sizing the subglottic airway uses the outer diameter of the pediatric endotracheal tube (ETT) during microlaryngobronchoscopy. 1 Assessing stenosis by obtaining an air leak as originally described requires close-fitting the ETT instrumentation to size the airway. This technique arose from practical neces- sity and an inability to obtain accurate measurements endos- copically. This technique may be time-consuming and potentially traumatic. Measurement is inaccurate in irregular or soft pathologies, for example, granulations for which longitudinal monitoring is relevant to clinical care. Three-dimensional endoscopic measurement technologies and the integration of a ‘‘virtual ruler’’ have been in devel- opment, yet their clinical applicability to pediatric airway assessment has not been evaluated. 2,3 Within engineering, an integrated endoscopic multipoint laser system (EMLS) is used for engine and wind turbine evaluation. A 4.4-mm flexible videoscope is integrated with a laser tool generating a 7-by-7 grid of coordinates over the endoscopic view (Figure 1). A 3-dimensional model of the object surface within this view is instantaneously created through shape deformation of the grid pattern. Simultaneous inspection and measurement can thereby occur. Distances, areas, and depth can subsequently be measured from any angle of view and without time-consuming quantification of the endoscope position relative to the stenosis itself. This advance allows us to consider faster, more accurate, and less traumatic means to formally measure airway stenosis. We evaluated EMLS accuracy within a validated pediatric airway preclinical simulation model prior to potential clinical use. Methods The AirSIM Child Bronchi X simulation model (Tru-Corp, Co, Armagh, Northern Ireland) was used to validate the accuracy of the measurement method. This has removable front-of-the-neck access of the larynx and trachea that allows creation and customization of subglottic stenosis (Figure 2). By passing an uncuffed pediatric ETT of a known size through modeling clay, 3 specimens of subglottic stenosis 1 Great Ormond Street Hospital for Children, London, UK 2 UCL Institute of Child Health, London, UK This work was short listed for the Susannah Leighton oral presentation prize at the British Pediatric Otolaryngology Meeting; September 20, 2019; Edinburgh, UK. Corresponding Author: Andrew Christopher Hall, FRCS, Consultant Pediatric Otolaryngology (Locum), Great Ormond Street Hospital for Children, Great Ormond Street, Holborn, London, WC1N 3JH, UK. Email: andrew.hall@gosh.nhs.uk