Microbolus vs Linear Thread Injection — Policy & Procedure

1. Purpose

To standardise safe, evidence‑based selection between microbolus and linear thread hyaluronic acid (HA) filler techniques across facial sub‑units; and to codify asepsis, documentation, and complication response under Australian regulatory frameworks. ¹ ³

2. Scope

Applies to all cosmetic doctors and nurses performing dermal filler injections at Newcastle Cosmetic Doctor, under direct or delegated supervision consistent with AHPRA/NMBA scope and prescribing rules. ¹ ³

3. Policy Statement

Technique selection follows anatomical plane, product rheology (G′, tanδ, cohesivity), intravascular risk, and intended effect (lift vs blend). Only TGA‑included devices are used with full batch traceability; Schedule 4 advertising restrictions apply; hyaluronidase and VO kit are immediately accessible. ² ⁶

4. Definitions

Microbolus: discrete 0.01—0.02 mL deposits for structural projection in deep planes with high‑G′ gels. Linear thread: continuous or segmented 0.05—0.1 mL per thread along the withdrawal path to blend transitions in subcutaneous/superficial fat. ⁵ ⁷

5. Governance & Credentialing

Annual competencies include VO simulation, hyaluronidase reconstitution, IPC/ANTT, and ocular‑emergency drills. Records must include consent, injection map, ARTG/UDI, batch/expiry, and prescriber details where applicable. ¹ ³ ⁶

6. Pre‑Procedure Safety

Medical review, skin prep per RACGP IPC, ultrasound considered for high‑risk zones (temple, nose, glabella, tear trough). Emergency kit visible and in date. ³ ⁷

7. Technique Selection Framework

Structure/lift → microbolus (deep, high‑G′). Blend/line effacement → linear threading (superficial/subcutaneous, lower G′). Aspiration is unreliable—prioritise slow/low‑pressure injection, small aliquots, correct plane, and stable needle/cannula control. ⁴ ⁵

8. Procedure Checklist

Time‑out (ID, indication, area, product/ARTG/LOT/expiry, consent). Asepsis per RACGP IPC. Device plan and dosing limits per region. Emergency kit at hand. ³

9. Complication Management

Cutaneous VO: stop, massage, warm compress, high‑dose pulsed hyaluronidase infiltrated throughout the ischaemic field with repeat dosing guided by reperfusion. Any visual symptoms: activate RANZCO pathway and urgent ophthalmology transfer; do not delay with prolonged in‑clinic measures. Tyndall: low‑dose targeted hyaluronidase with review in 48—72 h. ⁴

10. Audit & Review

Quarterly audit comparing outcomes by technique and region (VO rate, Tyndall, nodules, revisions) and annual peer‑review workshop on rheology/ultrasound/emergency drills. ⁶

Sources

Ahpra (2025) Performing non‑surgical cosmetic procedures — Guidelines hub., viewed 05 November 2025, https://www.ahpra.gov.au/Resources/Cosmetic-surgery-hub/Cosmetic-procedure-guidelines.aspx ↩
Therapeutic Goods Administration (TGA) (2024). Cosmetic injectables and safety standards, viewed 04 November 2025, https://www.tga.gov.au/ ↩
RACGP (2024) Infection prevention and control guidelines for general practices., viewed 05 November 2025, https://www.racgp.org.au/running-a-practice/practice-standards/racgp-infection-prevention-and-control-guidelines ↩
Therapeutic Goods Administration (TGA) (2024), Advertising health services & cosmetic injections – FAQs, viewed 05 Nov 2025, https://www.tga.gov.au/products/regulations-all-products/advertising/specialised-advertising-issues-and-topics/advertising-health-services-and-cosmetic-injections-frequently-asked-questions-and-answers ↩
ASAPS (2021), Cosmetic plastic surgery patient safety guide (governance & safety), viewed 05 November 2025, https://aestheticplasticsurgeons.org.au/wp-content/uploads/2022/02/FINAL-ASAPS-GUIDE-Patient-Safety-Oct21.pdf ↩
Therapeutic Goods Administration (TGA) (2024), Understanding your post-market responsibilities for medical devices, viewed 05 November 2025, https://www.tga.gov.au/resources/guidance/understanding-your-post-market-responsibilities-medical-devices ↩
Allergan Aesthetics (AbbVie) (2025), Allergan Medical Institute — Australia: Education overview (injection anatomy & vascular safety modules; restricted access), viewed 05 November 2025, https://www.allerganaesthetics.com.au/providers/education ↩

Disclaimer for Newcastle Cosmetic Doctor Policies & Procedures

The policies and procedures contained within this document are the exclusive property of Newcastle Cosmetic Doctor and are provided for internal clinical governance and educational purposes only. These materials represent the internal operational framework, safety standards, and evidence-based protocols developed and implemented by Dr. Bart John Scanlon and the Newcastle Cosmetic Doctor team. They are designed specifically for use within Newcastle Cosmetic Doctor and reflect our clinic’s own professional standards, risk assessments, and compliance obligations under Australian law and regulatory authorities. External individuals, practitioners, or organisations must not copy, reproduce, distribute, or rely upon these materials, in whole or in part, for their own clinical, commercial, or educational use without prior written consent from Newcastle Cosmetic Doctor. These materials do not constitute medical, legal, or professional advice and are not intended to be adopted as official protocols or procedures by any other entity. Any external use or adaptation must be independently reviewed and modified to meet the relevant laws, guidelines, and standards applicable to the user’s own jurisdiction, scope of practice, and facility operations. Newcastle Cosmetic Doctor and Dr. Bart Scanlon accept no liability for any loss, injury, or damage arising from the unauthorised use, reliance upon, or misinterpretation of this material.