Effect of Chitosan Phonophoresis on Cervical Pain, Disability and Cervical Range of Motion in Smartphone-Addicted Users Aged 16–19 Years: Randomized Controlled Trial

Background and Purpose: Prolonged smartphone use may contribute to cervical pain through sustained muscular overload and increased nociceptive input. This study investigated the effects of adding chitosan phonophoresis to conventional physical therapy on pain, disability, and cervical range of motion (ROM) in smartphone-addicted adolescents with cervical pain. Methods: Thirty-two participants aged 16–19 years with smartphone addiction and cervical pain were randomly assigned to a chitosan phonophoresis group or a control group. Outcomes were assessed before and after treatment using the Neck Disability Index (NDI), Visual Analog Scale for Pain (VAS-P), and cervical range-of-motion (CROM) device. Results: Both groups improved significantly after treatment. Compared with the control group, the chitosan phonophoresis group showed greater reductions in VAS-P (MD = −1.00, 95% CI: −1.59 to −0.41; p = 0.002) and NDI (MD = −3.13, 95% CI: −5.00 to −1.23; p = 0.002). Greater improvements were also observed in cervical ROM, including flexion (MD = 5.63°, 95% CI: 2.58 to 8.67), extension (MD = 6.25°, 95% CI: 1.90 to 10.59), right bending (MD = 3.75°, 95% CI: 1.74 to 5.76), left bending (MD = 4.38°, 95% CI: 1.95 to 6.79), right rotation (MD = 6.25°, 95% CI: 3.70 to 8.80), and left rotation (MD = 6.25°, 95% CI: 3.19 to 9.30; all p < 0.001). Conclusions: Adding chitosan phonophoresis to conventional physical therapy produced greater improvements in cervical pain, disability, and ROM. However, between-group differences in pain and disability were below commonly reported thresholds for clinically important change. Chitosan phonophoresis may be a useful adjunct in managing cervical disorders associated with prolonged smartphone use.