When Hyalase Doesn't Work - What Ultrasound Reveals

Jul 28

5 min read

Updated: 16 hours ago

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.

Aquamid filler on POCUS - ZNG Plastic Surgery, Singapore — 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 - Tear Trough Filler 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.

Persistent tear trough filler despite hyalase - ZNG Plastic Surgery, Singapore — 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.

A patient who was told her filler could always be reversed with hyalase, and who is now on her third failed dissolving attempt five years later, is living that consequence.

The management plan in this case 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.

Case 3 – 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 images of PCL injection, ZNG Plastic Surgery Singapore — POCUS scan 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.

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. Winner of ISAPS Bronze Medal for Rhinoplasty (2025), and Best Abstract Award (2024) at the London Rhinoplasty Course, Techniques in Rhinoplasty with an Integrated ENT-Plastics Approach.

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