Carbon Dioxide Gas-Assisted Subcision and PDLLA infusion for Horizontal Neck Lines

Horizontal neck lines (HNLs), also termed transverse cervical creases or "Venus rings," deepen with age due to dermal thinning, alterations in the superficial cervical fascia and retinacula cutis, and repetitive platysmal motion. Conventional treatments-including hyaluronic acid (HA) fillers, energy-based devices, and microneedling radiofrequency-primarily target texture and volume but may not adequately address tethering within the superficial fascia.

To describe a carbon dioxide (CO₂) gas-assisted subcision technique for HNLs that combines mechanical release of fibrous septa within the superficial cervical fascia with biological stimulation through hypercapnia-induced vasodilation, microcirculatory enhancement, and fibroblast activation.

A CO₂ subcision and PDLLA delivery system (Trifill Pro, MCURE, Korea) and a 30-gauge needle were used to perform a three-step procedure: (1) initial CO₂ subcision to mechanically release fibrous septa within the superficial cervical fascia; (2) injection of PDLLA (Juvelook, VAIM, Korea) using Trifill Pro into the upper subdermal plane; and (3) a final CO₂ burst to homogenously disperse the biostimulatory agent along the crease. Outcomes were assessed using the Wrinkle Severity Scale (WSS) by blinded independent evaluators, patient-reported satisfaction (5-point Likert scale), and Global Aesthetic Improvement Scale (GAIS) at baseline, 1, 3, and 6 months post-treatment.

All 32 patients completed the 6-month follow-up. Mean WSS scores improved significantly from 3.41 ± 0.50 at baseline to 1.31 ± 0.47 at 6 months (mean reduction: 2.10 points, 61.6% improvement; p < 0.001).

CO₂ gas-assisted subcision and PDLLA injection represents a minimally invasive, fascia-oriented approach for HNLs, combining mechanical release of retinacular tethering with biological remodeling.