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Conflict of Interest: The authors have no potential conflicts
of interest to declare.
Financial Disclosure: This research received no specific grant
from any funding agency in the public, commercial, or not-for-profit
sectors.
ABSTRACT
Objectives: Nasopharyngeal (NP) depth prediction is clinically
relevant in performing medical procedures, and enhancing technique
precision and safety for patients. Nonetheless, clinical predictive
variables and normative data in adults remain limited. This study aimed
to determine normative data on NP depth and its correlation to external
facial measurements.
Methods: A multicenter cross-sectional study obtained data from
adults presenting to otolaryngology clinics at five sites in Canada,
Italy, and Spain. Investigators compared the endoscopically measured
depth from sill to nasopharynx along the nasal floor to the facial
measurements ”curved distance from the alar-facial groove along the face
to the tragus” and ”distance from the tragus to a plane perpendicular to
the philtrum.” When sinus CT images were available, the distance from
the nasopharynx to nasal sill was also collected.
Results: 371 patients participated in the study (41% women; 51
years old, SD 18). The average endoscopic depth was 9.4 cm (SD 0.86) and
10.1 cm (SD 0.9) for women and men, respectively (p<0.001;
95% CI 0.46 to 0.86). Perpendicular distance was strongly correlated to
NP depth (r=0.775; p<0.001), with an average underestimation
of 0.1 cm (SD 0.65; 95% CI 0.06 to 0.2). The equation: ND(cm) =
perpendicular distance*0.773 + 2.344, generated from 271 randomly
selected participants, and validated on 100 participants, resulted in a
0.03 cm prediction error (SD 0.61; 95% CI -0.08 to 0.16).
Conclusions : Nasopharyngeal depth can be accurately
approximated by the distance from the tragus to a plane perpendicular to
philtrum. The generated predictive equation was most accurate but not
likely clinically relevant.
Keywords: Nasopharynx, Nasopharyngeal Depth, COVID-19,
Temperature monitoring, Diagnostic Testing, Evidence-Based Practice.