Pathophysiology of aspiration in a unilateral SLN lesion model using quantitative analysis of VFSS

Objective: The purpose of this study was to elucidate the pathophysiology of aspiration in previously studied female infant piglets after a unilateral superior laryngeal nerve (uSLN) lesion. Methods: Videofluoroscopic swallow studies (VFSS) were acquired from 15 female piglets ages 2–3 weeks (9 with uSLN lesion and 6 controls). VFSS were analyzed at 30 frames/second sampling rate. Quantitative measures were conducted and compared between groups using published methodologies for VFSS assessment in adult and infant humans. Measures included the: 1) number of lingual-palatal contacts (LPC) (i.e. pre-swallow), 2) total pharyngeal transit time (TPT), 3) offset of swallow (offP), as well as onset of: 4) pharyngeal stage (onP), 5) pharyngoesophageal segment opening (oPES), 6) maximum PES opening (maxPES), 7) airway closure onset (oAC), and 8) maximum airway closure (maxAC). Measures 5–7 were determined relative to onP. Bolus residue was rated by severity (0 (none) to 3 (severe)). A gamma regression was used to compare continuous measures between lesioned and control groups. Results: The number of LPC (p =.006), TPT (p =.023) and timing of maxAC (p =.041) were significantly greater in the uSLN lesion than the control group. Conclusions: Outcomes of this study replicated prior published findings and elucidated that piglets with right uSLN lesions exhibited delayed maxAC. Noteworthy was the use of clinically relevant quantitative videofluoroscopic measures in piglets for comparison to future studies in human pediatric populations.