Internal Kinematics of the Volume-Reduced Tongue: A Longitudinal Microsonometric Study

This study examined tongue internal kinematics during feeding over time after its volume reduction. Six ultrasonic crystals were implanted into the tongue to record distance changes in anterior width (AW), bilateral lengths (LENG), posterior thicknesses (THICK), and posterior dorsal (PDW) and ventral (PVW) widths in five sibling pairs of Yucatan minipigs (N = 10). In each pair, one received tongue volume reduction surgery (reduction), and the other had the identical incisions without tissue removal (sham). Functional deformation of the tongue from preimplanted ultrasonic crystals was recorded during natural feeding 1 day before, 7-8, 13-15, and 28-30 days after the surgery. The results revealed that feeding behavior and tongue functional deformation were unchanged over time in the sham pigs. However, at Days 7-8, more frequent and longer ingestion episodes were seen in the reduction as compared with the sham. Moreover, deformational changes in AW and LENG decreased, whereas those in THICK, PDW, and PVW increased significantly (P < 0.001). At Days 13-15, the reduced deformational changes in LENG (P < 0.01) slightly restored, and the increased deformation in THICK (P > 0.05), PDW (P < 0.01), and PVW (P < 0.05) diminished. At Days 28-30, the restoration of AW and LENG continued (P < 0.01-0.05), but previously enhanced deformations in THICK, PDW, and PVW were no longer significantly different from the baseline (P > 0.05). These results suggest that the tongue volume reduction has significant and persistent impacts on feeding behaviors and tongue internal kinematics, and the restoring capacity of internal kinematics in the anterior tongue is limited and incomplete over time.