Supplementary Material for: Postoperative swallowing function in patients with deep neck infection

Introduction: Early detection of dysphagia risk, initiating rehabilitation, and resumption of appropriate diet based on swallowing function is important during deep neck infection control. This study aimed to evaluate the extent of cervical abscess development, particularly in the deep neck space, and its relationship to postoperative swallowing function. Methods: A retrospective chart review was performed for all deep neck infection cases treated between April 2015 and April 2021. Deep neck spaces were divided into categories based on computed tomography (CT) findings. Functional Oral Intake Scale (FOIS) scores of 4 or higher was defined as normal or slight swallowing disorder, and 3 or lower as dysphagia. Results: 17 cases were included in the analysis. Based on FOIS, 14 cases were classified into the dysphagia group at 2 weeks after surgery, 11 cases at 4 weeks, and 8 cases at 8 weeks. There was no significant difference between the location of the abscess and dysphagia at 2 weeks after surgery. Patients with anterior cervical space abscess significantly increased dysphagia 4 weeks (p= 0.018) and 8 weeks (p= 0.036) after surgery. Conclusion: Abscess formation in the anterior cervical space may be associated with prolonged dysphagia after treatment due to inflammation and scarring of the muscles associated with swallowing.