Evaluation of Rosenmüller fossa depth and nasopharyngeal structures in individuals with cleft lip and palate using cone-beam computed tomography

Background Cleft lip and palate (CLP) is a malformation traditionally attributed to muscle dysfunction but with deep anatomical origins. While early radiological signs of nasopharyngeal carcinoma often present as an asymmetric obliteration of the Rosenmüller fossa (RF), the impact of congenital CLP-related variations on this clinical detection remains a subject of debate with no definitive consensus. This study investigates these hypotheses by evaluating nasopharyngeal structural remodeling using cone-beam computed tomography (CBCT). To determine whether the morphometric changes are local or regional, unilateral (cleft/non-cleft sides), bilateral, and healthy individuals were compared. Based on our measurements, results indicate a specific structural transformation in the CLP nasopharynx characterized as a ‘narrow and long’ configuration, with both sides similarly affected even in unilateral cases. These findings suggest that CLP should be viewed not merely as a localized anatomical defect, but rather as a regional morphometric remodeling involving the entire nasopharyngeal complex. Methods This retrospective study analyzed CBCT images of 78 CLP and 78 healthy individuals. Parameters included RF depth and type, torus levatorius (TL) length, inter-torus distance (ITD), posterior nasal spine - posterior pharyngeal wall distance (PNS-PPW), eustachian tube length (ETL), ET angle (ETA), tympanotubal angle (TTA), and pharyngeal bursa (PB) presence. Subjects were categorized as unilateral (cleft/non-cleft sides), bilateral, or control. Results RF morphological types varied significantly between groups ( p = 0.022), although RF depth ( p = 0.155) and PB presence showed no significant differences. CLP groups exhibited significantly higher TTA and TL length ( p < 0.001) and increased PNS-PPW distance, particularly in bilateral cases ( p < 0.001). Conversely, ETL ( p = 0.047) and ITD ( p = 0.009) were significantly higher in controls. ETA showed no significant difference. Conclusions CLP appears to be associated with morphometric remodeling of the nasopharynx and the eustachian tube, which is more pronounced in bilateral cases. These structural abnormalities may provide a potential framework for assessing velopharyngeal dysfunction and middle ear pathologies in this population.