Abstract

Objectives: 1. Recognise the anatomical relationship between midface filler injection zones and functional anatomy. 2. Identify patient-specific anatomical risk factors, such as septal deviation and narrow valve angles, that may predispose to dynamic valve collapse. 3. Apply practical complication management strategies, including conservative measures and when to escalate to hyaluronidase to preserve airway function and cosmetic results. Introduction: Hyaluronic acid fillers are trusted tools for restoring midface volume and softening nasolabial folds, with an established safety record for vascular and contour risks. However, the potential for functional nasal airway complications remains under-recognised in routine practice. This case presents an unexpected internal nasal valve collapse after deep filler placement near the pyriform aperture, highlighting the interplay between aesthetic midface volumisation and subtle functional nasal anatomy that can affect airflow. Materials / method: A healthy 50-year-old woman underwent nasolabial fold augmentation with 0.4 mL hyaluronic acid filler per side into the deep dermal and supraperiosteal plane near the pyriform fossa. Three days later, she developed new unilateral nasal obstruction and inspiratory noise. Examination showed dynamic collapse of the left internal nasal valve, resolving with lateral cheek traction (positive Cottle manoeuvre). High-resolution clinical images and video documented diagnosis, treatment steps, and outcome. Results: A stepwise conservative approach was used to resolve the nasal valve collapse without sacrificing the cosmetic outcome. Warm compresses, firm directional massage away from the valve region using neutral emollient, and a short course of intranasal corticosteroid spray restored normal breathing by day 20. Hyaluronidase was avoided to maintain volume. Final review confirmed no residual functional obstruction and satisfactory fold correction. The video clearly demonstrates valve dynamics pre- and post-treatment. Conclusion: This case demonstrates that midface filler injections can affect functional nasal valve competence, especially in patients with unrecognised mild septal deviation or narrow valve angles. A clear understanding of nasal anatomy, careful plane and volume control near the pyriform aperture, and prompt recognition of inspiratory collapse allow practitioners to manage such rare complications conservatively. Awareness of this risk helps maintain safe practice standards, balancing functional and aesthetic goals in everyday filler treatments.