Purpose

Provide an anatomy-led, defensible framework for hyaluronic acid (HA) filler along the mandibular border, angle, and prejowl sulcus, aligned with Australian regulation and international safety guidance.^{1 2 3 4}

1. Regional Anatomy & Risk

The facial artery crosses the mandible at the antegonial notch before ascending; the submental branch courses along the inferior border. The marginal mandibular nerve runs superficial to the facial vessels and is vulnerable to oedema or haematoma. Deep, avascular planes on periosteum are safer for structural contouring, whereas mid-dermal injections increase intravascular risk.^{2 3 4}

2. Indications & Patient Selection

Indications include mandibular angle definition, camouflage of prejowl sulcus, and restoration of skeletal contour in age-related descent. Selection considers skin thickness, skeletal projection, masseter hypertrophy, and weight fluctuation. Contraindications include active infection, poorly controlled systemic disease, and unrealistic expectations; brief psychological screening reduces dissatisfaction risk.^{1 5}

3. Product Science & Selection (HA Rheology)

Use higher G′, cohesive HA gels for lateral jawline scaffolding and angle definition, balancing lift with moldability to avoid edges. In the prejowl, a slightly lower G′ can soften transitions. Particle size, crosslinking, and cohesivity influence projection and spread; hydration profile impacts oedema risk.^{6 7 8}

4. Injection Technique & Dosing

Prefer a 22–25G blunt cannula via lateral or posterior entry for long, controlled linear threads along the mandibular border, keeping to the deep supraperiosteal plane. For angle projection, consider small supraperiosteal boluses (0.1–0.3 mL) with firm aspiration and very low pressure; avoid static boluses over the antegonial notch. Advance cannula in a single plane, with frequent perfusion checks and injection speed ≤0.1 mL/s.^{2 5 9}

Typical dosing per hemiface is 0.5–1.5 mL for contour refinement, escalated in staged sessions to allow tissue accommodation and appraisal. Record planes, entry points, volumes per pass, and massage strategy for reproducibility and audit defensibility.^{4 10}

5. Red Flags & Vascular Occlusion Response

Stop for disproportionate pain, blanching, livedo, or coolness; leave cannula in place to aspirate if possible. Initiate high-dose hyaluronidase with warmth and massage, consider antiplatelet measures per local guidance, and escalate urgently where visual symptoms or extensive ischaemia present. Document batch/lot numbers and actions; consider TGA DAEN reporting for serious events.^{11 12 13}

6. Non‑Vascular Complications

Potential issues include contour irregularity, oedema, nodules or biofilm, neuropraxia of the marginal mandibular nerve, and late migration. Management ranges from massage and watchful waiting to targeted hyaluronidase or antimicrobial therapy after assessment. Structured follow‑up at 2–4 weeks supports early identification and remediation.^{9 14}

7. Documentation, Consent & Governance Alignment

Use AHPRA‑compliant consent with clear explanation of benefits, risks, alternatives, costs, and cooling‑off where applicable. Record standardised photos, product name, ARTG, batch/lot, volumes and planes; store images and records per Australian Privacy Principles. Audit outcomes within NSQHS Clinical Governance and report significant device or medicine issues via TGA mechanisms.^{1 15 3}

8. Aftercare & Review

Written aftercare: avoid heavy pressure, heat, and strenuous exercise for 24 hours; intermittent cold compress; monitor for increasing pain, colour change, or sensory change. Reassess at 2–4 weeks to refine symmetry, palpate for firmness, and plan staged dosing if further projection is desired.⁹

Sources

1. AHPRA, Guidelines for registered medical practitioners who perform cosmetic medical and surgical procedures (2025), viewed 28 October 2025, https://www.ahpra.gov.au/Resources/Cosmetic-surgery-hub/Cosmetic-procedure-guidelines.aspx ↩
2. ACE Group World, Injection Complications: Prevention & Management Algorithms, viewed 28 October 2025, https://uk.acegroup.online/ ↩
3. ACSQHC, NSQHS Standards: Clinical Governance & Partnering with Consumers, viewed 28 October 2025, https://www.safetyandquality.gov.au/standards/nsqhs-standards ↩
4. NSW Health, Clinical Governance in NSW (Policy Directive PD2025_032), viewed 28 October 2025, https://www1.health.nsw.gov.au/pds/ActivePDSDocuments/PD2025_032.pdf ↩
5. Cotofana S, et al., Arteries of the Face and Their Relevance for Minimally Invasive Facial Procedures: An Anatomical Review (2019), Plast Reconstr Surg, viewed 28 October 2025, https://pubmed.ncbi.nlm.nih.gov/30688884/ ↩
6. Freytag DL et al. (2019), Facial Safe Zones for Soft Tissue Filler Injections, Journal of Drugs in Dermatology, 18(9), 896–902, viewed 28 October 2025, https://pubmed.ncbi.nlm.nih.gov/31524345/ ↩
7. Brennan C, Avoiding the "danger zones" when injecting dermal fillers and volume enhancers, Aesthetic Surg J, viewed 28 October 2025, https://pubmed.ncbi.nlm.nih.gov/25188847/ ↩
8. RACGP, Cosmetic and procedural medicine: patient assessment guidance, viewed 28 October 2025, https://www.racgp.org.au/ ↩
9. Hong, Gi-Woong et al., Review of the Adverse Effects Associated with Dermal Filler Treatments: Part I Nodules, Granuloma, and Migration. (2024), viewed 28 October 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11311355/ ↩
10. Heitmiller K, Ring C, Saedi N. Rheologic properties of soft tissue fillers and implications for clinical use. J Cosmet Dermatol. 2021; 20: 28–34. https://doi.org/10.1111/jocd.13487 ↩
11. Sundaram H, et al., Cohesivity of Hyaluronic Acid Fillers: Development and Clinical Implications of a Novel Assay, Pilot Validation with a Five-Point Grading Scale, Plast Reconstr Surg, viewed 28 October 2015, https://pubmed.ncbi.nlm.nih.gov/26397245/ ↩
12. de Maio M, MD Codes™: A Methodological Approach to Facial Aesthetic Treatment with Injectable Hyaluronic Acid Fillers, Plast Reconstr Surg, viewed 28 October 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8012343/ ↩
13. WHO, Patient Safety: Learning systems and incident reporting, viewed 28 October 2025, https://www.who.int/teams/integrated-health-services/patient-safety ↩
14. TGA, Database of Adverse Event Notifications (DAEN), viewed 28 October 2025, https://www.tga.gov.au/safety-and-shortages/database-adverse-event-notifications-daen ↩
15. Australian Resuscitation Council (ARC), Anaphylaxis & BLS Guidelines, viewed 28 October 2025, https://resus.org.au/guidelines/ ↩
16. ACE Group, Vascular occlusion emergency pathway, viewed 28 October 2025, https://uk.acegroup.online/ ↩
17. Haneke H (2015), Managing complications of fillers: Rare and not-so-rare, Clinical, Cosmetic and Investigational Dermatology, 8, 429–444, viewed 28 October 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC4728901/↩
18. OAIC, Australian Privacy Principles (Privacy Act 1988), viewed 28 October 2025, https://www.oaic.gov.au/privacy/australian-privacy-principles ↩