Cross‑Product Layering SOP - Dermal Filler

Applies to: Licensed medical practitioners and nurses working under medical delegation in accredited clinics.

Clinical governance disclaimer: This SOP provides evidence‑based guidance for trained clinicians. It does not replace local law, device Instructions for Use, or clinical judgement. Follow emergency protocols for suspected vascular events without delay.

1. Purpose & Scope

Define evidence‑based principles for layering different filler classes (HA, CaHA, PLLA, PMMA) across planes and sessions to optimise projection, support and surface refinement while lowering complication risk. Aligns with Australian governance (AHPRA/TGA/RACGP/CPCA) and international safety guidance. ¹ ² ³ ⁴

2. Indications & Clinical Rationale

Cross‑product layering is used for complex facial volume loss where a single filler class cannot meet both structural and surface demands. Strategy: deep structural support first, then superficial polish. Rationale: combine immediate lift/cohesivity with biostimulation or high‑definition contouring while respecting planes to avoid product interaction, migration or nodularity. ⁵ ⁷ ⁹

3. Product Classes & Planes

Hyaluronic acid (HA): reversible gels with variable G’/cohesivity; used from supraperiosteal to dermal planes depending on rheology.
Calcium hydroxylapatite (CaHA): viscous particles in gel; deep structural or hyperdilute for biostimulation; avoid superficial dermis.
Poly‑L‑lactic acid (PLLA): biostimulator; series treatments; deep subcutaneous/supraperiosteal; not for lips/tear trough.
Polymethylmethacrylate (PMMA): permanent microspheres (e.g., Bellafill®); restricted indications; avoid intradermal use and be cautious with future layering.

Ultrasound can map vessels, verify plane/product location, identify legacy/migrated filler and guide dissolving or aspiration during complications.⁶

4. Compatibility Framework

Core rules:

Do not mix different products in the same syringe unless an approved hybrid device; keep products in distinct planes.
Prioritise structural filler (CaHA/robust HA/PLLA) deep; add superficial HA for contour/skin finish.
Use ultrasound to confirm separation where planes are tight or prior filler is present. ⁸ ¹¹ ¹² ¹³

Primary (deep)	Secondary (superficial)	Same‑session?	If staged	Notes
CaHA (supraperiosteal/deep SC)	HA (mid‑/superficial)	Yes — if strictly separate planes	2–4 weeks	Hybrid/combined approaches supported; avoid superficial CaHA.
PLLA (deep)	HA (superficial refinement/skinboosters)	Prefer staged	4–8 weeks	Allow collagen phase to begin before HA finish.
Robust HA (deep)	Soft HA (superficial)	Yes — if planes distinct	≥2 weeks	Touch‑ups once oedema resolves.
CaHA (deep)	PLLA (deep)	No (same area)	8–12 weeks, different planes	Avoid concurrent biostimulators in same plane.
PMMA (approved indications only)	Any other filler in same track	Avoid	Consider ≥3–6 months and different plane with ultrasound	Permanent; higher granuloma risk if disturbed.

Evidence base for the above: ¹¹ ¹² ¹³ ¹⁵.

5. Injection Planning & Technique

Plane hierarchy: correct skeletal/fat‑pad deficits (deep) first; then mid‑dermal/subdermal refinement.
Imaging: handheld high‑frequency ultrasound pre‑map and live‑guide in high‑risk zones; archive key frames to the record.
Cannula vs needle: choose based on target plane and precision; use minimal pressure and slow linear threading; aspirate where appropriate.
Volumes: micro‑aliquots; avoid bolus in compromised zones; never inject against capillary refill changes or pain.
Emergency readiness: immediate occlusion protocol and high‑dose hyaluronidase availability; escalate per algorithm.

Key safety data on ultrasound guidance and occlusion response: ⁶ ¹⁶ ¹⁷

6. Recommended Layering Intervals by Product Type

Sequence	Minimum interval (if staged)	Rationale	Sources
PLLA → HA (skinboosters/refinement)	4–8 weeks	Allow early collagen formation before adding superficial HA.	¹⁴ ¹⁵
CaHA (deep) → HA (superficial)	Same session if strictly separate planes; otherwise 2–4 weeks	Reduce interaction/edema confounders; strong evidence for safe combination when separated.	¹¹ ¹² ¹³
HA → HA (touch‑up)	≥2 weeks	Wait for oedema to settle; reassess symmetry.	¹⁶
CaHA ↔ PLLA (same area)	Avoid same session; if needed, 8–12 weeks and different planes	Limit additive granuloma/inflammatory risk from dual biostimulation.	¹⁵ ¹⁶
Any filler over recent PMMA (same track)	Avoid; consider ≥3–6 months with ultrasound mapping	Permanent microspheres—higher risk of nodules if disturbed.	¹⁹ ²⁰

7. Risk Management & Contraindications

Do not layer biostimulators with HA in the same plane in one sitting.
Avoid layering over migrated/unknown filler; map first with ultrasound and dissolve HA if needed.
Contraindications: active infection, poor wound healing states, autoimmune flares, pregnancy/breastfeeding, hypersensitivity to components (e.g., bovine collagen in PMMA formulations).
Monitor for delayed inflammatory reactions and nodules; treat per algorithm (hyaluronidase for HA, antibiotics/steroids when indicated; specialist referral for PMMA/CaHA nodules).

8. Clinical Governance (Australia 2025)

Practitioners must hold AHPRA registration and comply with the 2025 cosmetic procedure guidelines for performance and advertising.
Only TGA‑approved products (ARTG‑listed/registered) to be stocked and used in line with their IFU.
Document product, batch/lot, volume, injection plane, and ultrasound captures where used; obtain specific consent for cross‑product layering.
Report adverse events to the TGA (IRIS/MDIR). For dual‑registered devices treated overseas, also lodge to FDA MedWatch if applicable. ¹⁰ ² ¹⁷ ¹⁸

9. Documentation & Audit

Pre‑treatment: photography, risk consent, plane‑by‑plane plan, product identifiers.
Intra‑treatment: real‑time notes per syringe/cannula pass, adverse events, ultrasound screenshots if used.
Post‑treatment: aftercare given, review booked at 14—28 days, escalation triggers documented.
Audit: complications, Tyndall/nodules, vascular events, dissolving events, and all external reports (IRIS/MDIR/MedWatch).

10. Adverse Event Escalation — Micro‑Algorithm

Suspected intravascular event: stop, call for help, warm compresses, high‑dose hyaluronidase (repeat 10—20 min), massage to reperfuse, consider ultrasound‑guided flooding; ophthalmology pathway if ocular symptoms.
Delayed inflammatory nodule: classify (inflammatory vs non‑inflammatory). For HA, consider hyaluronidase +/- antibiotics/steroids; for CaHA focal accumulations, follow minimally‑to‑more invasive algorithm; for PMMA, refer early to specialist.
Report per Section 8; document fully.

Sources: ¹⁷ ²⁰

Sources

AHPRA — New guidelines for cosmetic procedures (2 Sep 2025), viewed 05 November 2025, https://www.ahpra.gov.au/News/2025-09-02-New-guidelines-for-cosmetic-procedures.aspx ↩
TGA — Adverse event reporting for medical devices (updated 26 Aug 2025), viewed 05 November 2025, https://www.tga.gov.au/safety-and-shortages/adverse-events/medical-device-adverse-events/obligations-report-adverse-event-medical-devices ↩
CPCA — Policies & Guidelines, viewed 05 November 2025, https://cpca.net.au/policies-guidelines/ ↩
RACGP (2024) Infection prevention & control guidelines (primary care)., viewed 05 November 2025, https://www.racgp.org.au/running-a-practice/practice-standards/racgp-infection-prevention-and-control-guidelines ↩
Sito G, Manzoni V, Sommariva R. (2021), Hyaluronic Acid Fillers: A Comprehensive Review of Complications and Safety, Journal of Clinical Medicine, 10(4):780, viewed 05 November 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8748115/ ↩
Cral W.G. (2022), Ultrasonography and Facial Aesthetics, Aesthetic Plastic Surgery, 46(2):999-1000, viewed 05 November 2025, https://pubmed.ncbi.nlm.nih.gov/34241666/ ↩
Journal of Clinical & Aesthetic Dermatology (JCAD) (n.d.), Dermal Fillers – Areas of Interest, viewed 05 November 2025, https://jcadonline.com/areas-of-interest/dermal-fillers/ ↩
Mehta P. (2022), Non-ischemic complications of dermal fillers, Open Access Emergency Publish (OAE Publish), viewed 05 November 2025, https://www.oaepublish.com/articles/2347-9264.2022.28 ↩
Modarressi A., Nizet C., Lombardi T. (2020), Granulomas and nongranulomatous nodules after filler injection: Different complications require different treatments, Journal of Plastic, Reconstructive & Aesthetic Surgery, 73(11):2010-2015, viewed 05 November 2025, https://pubmed.ncbi.nlm.nih.gov/32928687/ ↩
AHPRA — Non‑surgical cosmetic procedures hub (reviewed 2 Sep 2025), viewed 05 November 2025, https://www.ahpra.gov.au/Resources/Cosmetic-surgery-hub/Information-for-the-public/Injectables.aspx ↩
Fakih‑Gomez et al., Combining CaHA and HA (PMC8831259), viewed 05 November 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC8831259/ ↩
Bravo et al., 2024 — Blending HA & CaHA (MDPI), viewed 05 November 2025, https://www.mdpi.com/2079-9284/11/2/61 ↩
Meçani et al., 2025 — HA+CaHA combinations (Aesthetic Plast Surg), viewed 05 November 2025, https://link.springer.com/article/10.1007/s00266-025-04904-x ↩
Bauer et al., 2011 — Optimising PLLA (intervals ≥4 weeks), viewed 05 November 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC3269336/ ↩
Munia et al., 2023 (JCAD) — Add HA skinboosters 30—60 days after PLLA, viewed 05 November 2025, https://jcadonline.com/skin-quality-acid-hyaluronic-acid/ ↩
Hong et al., 2024 — Adverse effects review; oedema timeline & risks, viewed 05 November 2025, https://pmc.ncbi.nlm.nih.gov/articles/PMC11276034/ ↩
FDA — Dermal Fillers (Soft Tissue Fillers) + MedWatch link, viewed 05 November 2025, https://www.fda.gov/medical-devices/aesthetic-cosmetic-devices/dermal-fillers-soft-tissue-fillers ↩
FDA — Reporting Serious Problems (MedWatch), viewed 05 November 2025, https://www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program/reporting-serious-problems-fda ↩
Bellafill® (PMMA) Instructions for Use (FDA), viewed 05 November 2025, https://www.accessdata.fda.gov/cdrh_docs/pdf2/P020012S009c.pdf ↩
McCarthy et al., 2024 — CaHA nodule algorithm (Aesthetic Surgery Journal), viewed 05 November 2025, https://academic.oup.com/asj/article/44/8/869/7609149 ↩

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.