When Hyalase Doesn't Work - Why Ultrasound Matters

Filler complications are far more common than the aesthetic industry acknowledges, and most are still managed blindly by eye, feel, and protocol. Below are some cases I have evaluated recently that illustrate why point-of-care ultrasound (POCUS) transforms complication management: it replaces guesswork with anatomy.

Case 1 - Aquamid in the Radix: A Permanent Filler and Its Consequences

A patient presented with a wide, flattened nasal bridge, often termed an “Avatar nose.” Over a decade prior, an aesthetic doctor had injected Aquamid, a permanent polyacrylamide hydrogel filler, into her radix.

Aquamid is not hyaluronic acid (HA); it cannot be dissolved with hyaluronidase (Hyalase). Over years, it spreads and integrates with surrounding soft tissue. Despite this, previous providers had subjected her to both needle aspiration and repeated Hyalase injections, futile attempts reflecting a fundamental misunderstanding of the material.

POCUS revealed an extensive hypoechoic deposit with irregular, poorly defined borders. There was no distinct capsule or surgical plane. Needle aspiration and suction cannot clear integrated material after ten years; the only realistic option is an open rhinoplasty approach to debulk and physically scrape away what is possible, accepting that complete removal in this scarred bed is unachievable.

POCUS scan of the radix in a patient, showing a large, indistinct, hypoechoic mass consistent with the history of Aquamid.

This is the predictable endpoint of permanent nasal fillers. It is also why I do not use it, nor recommend or offer it. A result that looks acceptable at one year can end up like this at year ten.

Case 2 & 3 - Tear Trough Fillers That Would Not Dissolve

A patient presented with a palpable, persistent “sausage roll” beneath her lower eyelid that had failed to improve after three rounds of Hyalase. The tear trough filler had been placed five years earlier.

POCUS revealed a well-defined, 10.85 mm deposit sitting directly on the bone (supra-periosteal), showing internal layering and partial, irregular fibrous encapsulation. This fibrotic envelope prevented injected Hyalase from penetrating the deposit, while "blind", repeated attempts in the periorbital zone risked creating further hollows and lead to what's known as posthyaluronidase syndrome.

POCUS scan showing filler placed in the supra-perisoteal plane, measuring approximately 10.85 mm across. However, note the irregularity of its contours (see yellow arrow) in the picture on the right, which is consistent with the history of unsuccessful hyalase attempts and likely encapsulation/fibrosis, which would be in keeping with the use of a HA filler with BDDE.

Furthermore, heavily cross-linked HA formulations (using Butanediol Diglycidyl Ether, BDDE) exhibit significant enzymatic resistance and delayed inflammatory potential over time. This is not a minor clinical footnote. A class action lawsuit filed in June 2024 against AbbVie in the United States District Court for the Northern District of Illinois specifically highlights BDDE as pro-inflammatory, citing scientific literature describing the combination of BDDE and HA as capable of triggering delayed granuloma formation.

POCUS scan showing the filler placed at just about 1 mm beneath the thin lower eyelid skin, and measured approximately 13.87 mm in length. Note the irregularities within the filler itself, which again is in keeping with the history of multiple unsuccessful Hyalase attempts, leading to encapsulation/fibrosis.

Compared with another patient, who has also had tear trough filler done, albeit abroad, and was told it was HA material. This led to a lump measuring about 1.5 cm across under her lower lashes, which was more prominent when smiling. Despite having tried Hyalase thrice in the last two to three years, it persisted.

POCUS confirmed my suspicions as the lump was located barely 1 mm beneath the skin, likely within the orbicularis oculi muscle (see above). There were also features in keeping with encapsulation and fibrosis, which is likely the result from previous unsuccessful Hyalase attempts. The point here is, at such superficial depths, blind injections might have missed the filler altogether, leading to the development of the fibrous shell, thereby rendering each subequent attempt harder.

Both patients were told their filler could always be reversed with Hyalase, yet both are now on their third failed dissolving attempt years later, and living with that consequence.

The management plan in both cases is ultrasound-guided dissolving, under direct real-time visualisation, to ensure it is placed at the exact depth of the filler deposit rather than in the surrounding tissue. My colleagues and I published on the superiority of this approach in 2025, through a systematic review and pilot meta-analysis, compared to "blind" landmark injection for filler complications. Following successful dissolution, the next steps would be fat grafting for volume restoration and nanofat for skin quality improvement in the tear trough area. Failure with dissolving would then necessitate surgical excision, either through direct or indirect approaches (e.g. subciliary, transconjunctival).

Cases 4 & 5 - The Persistent Lump Under the Eyes When Smiling

A patient travelled from abroad seeking POCUS because high-frequency ultrasound for aesthetic complications remains unavailable in her home country. Her chief complaint was a lump that appeared only when smiling. She had received multiple midface fillers years ago but not uncommonly, could not recall the exact products used.

Assuming it was residual HA, she was treated with Hyalase a year ago, and again three days before seeing me, with zero effect. POCUS explained why instantly:

• Intramuscular entrapment: The material was embedded within the fibers of the orbicularis oculi directly above the bone. This explained the dynamic deformity as the nodule bunched up only upon facial animation.

• Non-HA acoustic signature: Rather than an anechoic HA pool (see Case 2 above), POCUS demonstrated an ill-defined nodule with internal hyperechoic speckling, typical of biostimulatory microspheres. The images were highly suggestive of polycaprolactone (PCL) granulomas.

Faced with this image, I re-questioned her history. She then recalled having received Ellansé (polycaprolactone / PCL). PCL microspheres stimulate neocollagenesis and persist for years. Crucially, PCL does not respond to Hyalase.

POCUS stopped the cycle of futile enzyme injections. It directed our focus toward appropriate solutions such as targeted intralesional steroid therapy, surgical debulking if cosmetically warranted, or simply leaving it alone.

POCUS scan (transverse view, left; sagittal view, right) showing intramuscular (within orbicularis oculi) hypoechoic nodules with irregular borders in the tear trough/upper cheek areas, with sonographic evidence suggestive of posterior shadowing. This is most consistent with PCL granulomas, in keeping with the patient's history of prior Ellanse injections.

In contrast to an intramuscular biostimulator nodule bunching up upon animation, another patient presented specifically requesting POCUS-guided dissolving after becoming fixated on residual HA deposits seen on a prior scan, convinced that clearing them would resolve her persistent under-eye fullness, which also became noticeably more prominent when smiling.

However, correlating her POCUS findings with her dynamic clinical anatomy told a very different story. While small, scattered HA pockets were indeed visible on POCUS, they were not what was driving her lower-eyelid contour at rest or during animation. Instead, her fullness stemmed from true anatomical aging. Specifically, this was herniated orbital fat (of the medial, central, and lateral compartments) that became more prominent when smiling, paired with a deep tear trough tethered by the orbicularis retaining ligament (ORL).

I explained that we treat her anatomy, not her POCUS scan. Dissolving incidental, non-contributory HA deposits would not flatten prolapsed orbital fat pads or release a tight ORL tether. In fact, it would subject her to unnecessary risk, especially when the skin in this area is especially thin. In cases like hers, restraint comes first: leaving harmless filler remnants alone and addressing the actual structural cause through a transconjunctival lower blepharoplasty (with fat repositioning or excision and ORL release) if and when she wishes to pursue surgical correction.

Case 6 - The Almost 20-Year-Old "Collagen" Filler in the Chin

This patient presented with a persistent lower chin lump and ptosis creating a classic "witch's chin" deformity, having received what she was told was a "collagen" injection done abroad almost two decades ago. Hyalase treatment performed locally 3 to 4 years prior yielded minimal improvement.

Point-of-care ultrasound (POCUS) instantly unmasked the true culprit as it revealed a textbook "snowstorm" appearance with dense posterior acoustic shadowing, classic for unapproved liquid silicone (most likely) and chronic foreign-body reaction with tissue ingrowth.

POCUS scan showing a "snowstorm" with acoustic shadowing (left, transverse view), which is highly suggestive of silicone particles as their acoustic properties are different; and tissue ingrowth (right, sagittal view), which is in keeping with a chronic foreign body response.

Once again, this case highlights why detailed ultrasound mapping is vital for differentiating permanent fillers from degradable HA, saving patients from ineffective enzymatic dissolutions and guiding us towards definitive surgical excision for removal.

Why POCUS Changes Filler Management

Clinical examination only confirms that a problem exists. POCUS reveals what the problem is - the exact material, depth, tissue plane, and why standard reversal protocols have failed.

As delayed complications grow increasingly prevalent, POCUS should no longer be considered an optional luxury or worse, a fancy marketing tool. In filler complication management, it is the line between empirical guesswork with potential downstream effects, and precise, informed treatment.

Written by Dr Ng Zhi Yang, UK & Singapore accredited Plastic Surgeon.

References

• Wilde CL, Jiang K, Lee S, Ezra DG. The Posthyaluronidase Syndrome: Dosing Strategies for Hyaluronidase in the Dissolving of Facial Filler and Independent Predictors of Poor Outcomes. Plast Reconstr Surg Glob Open. 2024 Apr 23;12(4):e5765. doi: 10.1097/GOX.0000000000005765. PMID: 38655103; PMCID: PMC11037726.

• Garcia v. AbbVie Inc. Class Action Complaint. US District Court for the Northern District of Illinois. Filed June 27, 2024. https://www.aboutlawsuits.com/for-martha-juvederm-lawsuit-claims-fillers-caused-facial-scarring-disfigurement/

• AbbVie class action alleges company hid Juvederm nodule risk. ClaimDepot. https://www.claimdepot.com/cases/juvederm-class-action-alleges-abbvie-hid-granuloma-risk-from-patients

• Boey JJE, Boey JJJ, Chen Z, Cao T, Tan ASM, Ng ZY. Superior Outcomes with Ultrasound-Guided Hyaluronidase for Impending Filler-Induced Facial Skin Necrosis: A Systematic Review and Pilot Meta-Analysis. Aesthetic Plast Surg. 2025 Jul;49(13):3519-3525. doi: 10.1007/s00266-025-04707-0. Epub 2025 Jan 29. PMID: 39881073.

• Habibi S, Khorasanizadeh F, Etesami I, Tootoonchi N, Mahmoudi H, Balighi K, Wortsman X. Ultrasonographic Features of Polycaprolactone Granulomatous Reactions: Case Series and a Literature Review. Aesthet Surg J Open Forum. 2026 Jul 22;8:ojag116. doi: 10.1093/asjof/ojag116. PMID: 42488346; PMCID: PMC13390709.