English edition

materials

A face that has been injected several times is not one problem. It is several materials, placed at different depths, by different hands, in different years, each ageing in its own way. What the substance does over time decides whether it can be dissolved, aspirated or only cut out. Where it sits decides what has to be preserved while that is done.

The first half of this page goes material by material, the second region by region, because the same substance in the lower lid and in the cheek is not the same operation. A third section deals with foreign body granuloma, the reason a face that was quiet for years can become a problem without anything new being injected. Imaging patterns described are the usual ones and not a product identification: an old deposit, a mixture of materials, or advanced fibrosis will blur any of them.

01By material

Materials fall into three practical groups, and the grouping matters more than the brand name. There are materials that can be broken down by an injected enzyme. There are materials that cannot be broken down but are gradually resorbed over months or years. And there are materials that stay for life, or stay long enough that the distinction makes no difference to the person carrying them. Hyaluronidase acts only on the first group.

Hyaluronic acid

Cross-linked hyaluronic acid is the material most people have had, and the one most often blamed for problems it did not cause. It holds water, which is why it works and why it swells. Manufacturers state durations in months, and in mobile, well-perfused tissue those durations are roughly what happens. In still tissue with modest blood supply the same gel can sit for years. People are told a product lasts nine months, find a ridge under the eye five years later, and are then told it cannot possibly be filler.

On ultrasound it usually appears as well-defined pseudocystic spaces that read black, often with brightening of the tissue directly behind them. Older deposits are divided by internal septa and lose the clean outline, and where the gel has provoked a reaction the black pocket acquires a thick grey wall.

Removal usually begins with hyaluronidase rather than surgery. The injection is both treatment and an indirect test: material that reduces was probably hyaluronic acid, material that does not was probably something else, and neither conclusion is certain on its own. Surgery is considered when the deposit is walled off in a capsule the enzyme cannot reach evenly, when repeated sessions have made no difference, or when what remains is fibrous tissue rather than gel.

Polycaprolactone

Polycaprolactone products, of which Ellansé is the one usually named, are polymer microspheres suspended in a gel carrier. The carrier disperses within weeks. The microspheres remain, and the visible result comes largely from collagen the body lays down around them. The material is not a filler in the ordinary sense. It is a stimulus, and the volume is the body’s answer to it.

That is where the trouble comes from. When the collagen response overshoots, the same process produces firm, fixed nodules that no longer correspond to where the injection went. Polycaprolactone is not broken down by hyaluronidase. Patients are given dissolving injections anyway, sometimes several times, before anyone establishes what was injected, and those months are months in which the deposit becomes more adherent.

On ultrasound the pattern is small bright foci scattered through a darker matrix, without the clean black pockets of hyaluronic acid. As fibrosis advances the foci and the surrounding tissue converge, and the boundary the operation depends on becomes the hardest thing on the image to find.

Removal is surgical: excision under direct vision, or endoscopic removal where the region will not tolerate an open approach. The clinic describes pathology after removal of this material showing multinucleated giant cells and collagen deposition, which is the signature of a foreign body reaction rather than of the product.

Calcium hydroxylapatite

Calcium hydroxylapatite, usually encountered as Radiesse, is calcium microspheres suspended in a gel. The gel goes within months. The microspheres are resorbed over a period usually quoted as a year to eighteen months. Firm residue and calcified nodules can outlast that by a wide margin, particularly where the product was placed superficially.

Imaging is distinctive and, in one respect, unhelpful. The material is strongly bright with dense shadowing behind it, and the shadow obscures whatever lies underneath. The examination can establish that calcium is present and still not establish what is beneath it, which is often the information the operation needs. On CT the same material can read at a density close to bone.

No agent in routine use dissolves it, and it binds firmly to surrounding tissue, which is why difficulty increases with the interval since injection. Removal means incision, or an ultrasonic instrument to break down adherent portions, and the realistic aim is to reduce the part causing symptoms.

Poly-L-lactic acid

Poly-L-lactic acid, usually Sculptra, works on the same principle as polycaprolactone and on a slower clock. The particles are resorbed over months. The volume is collagen. The characteristic late problem is papules and nodules appearing after the treatment course has finished, most often where the skin is thin or the tissue moves a great deal.

On ultrasound the particles give small bright foci, less bright than calcium and casting little shadow, and an established nodule reads as a darker mass with bright dots inside it. In many cases the particles have largely gone by the time the nodule is examined, and what the image shows is the reaction, not the product.

This changes what removal means. There may be no substance left to take out. The operation removes the tissue the substance provoked, which is a different conversation to have beforehand, because the thing the patient wants removed no longer exists in the form they imagine. Where the nodules are small and untroubling, observation is often the better option.

Collagen-based injectables

Two different things are sold under the heading of collagen. Pure bovine or porcine collagen is resorbed over months and is rarely the cause of a late problem. The products that cause late problems are those in which collagen is only the vehicle. Artecoll and Artefill carry permanent polymethyl methacrylate microspheres suspended in collagen. The collagen resorbs on schedule. The microspheres do not resorb at all.

Patients are often unaware of this. They were told they had a collagen filler, they were told it was temporary, and they have since had years of firmness no one can account for. On ultrasound the microspheres appear as small bright dots of uniform size in a darker matrix. The permanent fraction cannot be dissolved, and removal means excising the tissue that contains it. Where that tissue is the lower lid or the lip, removing all of it would cost more than leaving some.

Polyacrylamide and older permanent materials

Polyacrylamide hydrogel, sold as Aquamid and under other names, belongs with an older group that includes paraffin, industrial-grade silicone and bio-alcamid. Some were licensed products of their era. Some were never medical products at all. What they have in common is that they do not stay where they were put.

Gels and oils travel along tissue planes with gravity and muscle action, so the lump a person can feel is frequently not where the injection was given. Presentations twenty and thirty years later are described: hardening, recurrent inflammation, discolouration, skin thinning, and in some cases a track that discharges to the surface.

Polyacrylamide appears as dark collections without a true capsule, tracking along planes rather than sitting in a pocket. Liquid silicone produces a dense scatter of bright signal with heavy shadowing, sometimes described as a snowstorm, which conceals everything deeper. Paraffin behaves similarly and adds a dense fibrous mass. In each case the image under-reads the true extent, and the surgeon should expect to find more than the scan showed.

Complete removal is not a realistic objective for material dispersed through tissue rather than pooled within it. Attempting it removes normal tissue in quantity and leaves deformity harder to treat than the original complaint.

Grafted fat that has hardened, clumped or migrated

Grafted fat is not a foreign material in the immunological sense, and it behaves like one when it does not survive. Take is always partial. The surviving portion is living fat and changes with body weight, which is why grafted cheeks can grow after weight gain. The portion that does not survive becomes oil cysts, fibrous tissue and, over time, calcification. Over-grafting produces firm lumps because the graft’s blood supply could not reach the middle of the volume placed.

On ultrasound an oil cyst is a rounded, mostly dark collection with a clear wall. Calcification appears as a bright rim or bright foci with shadowing, and on CT dense calcified graft can reach a density close to bone. Fibrosis reads as an ill-defined change in texture rather than as a mass, and it is the part hardest to separate from normal fat.

Removal is selective by necessity: aspiration for soft over-grafted fat, incision for firm calcified nodules, an ultrasonic instrument for adherent portions. The difficulty is the boundary. Grafted fat that has been in place for years looks and feels much like native fat, and the native fat is the tissue that must be kept. Where the boundary stays unclear close to a nerve, the clinic’s stated principle is to preserve.

Lifting threads

Threads come in absorbable form, usually polydioxanone, poly-L-lactic acid or polycaprolactone, and in non-absorbable form, usually polypropylene. Absorbable threads generally break down over months. The fibrous reaction they provoke lasts considerably longer than the thread, which is why a thread that has certainly dissolved can still be felt years later. What is being felt is the track, not the material.

Symptoms are mechanical more often than inflammatory. Barbed threads can tether tissue so that a dimple appears on smiling and disappears at rest. They can migrate, and they can work their way towards the skin or the mucosa and extrude.

On ultrasound a retained thread is a fine bright line, best seen along its length, and the track left by an absorbed thread can look very similar. Removal follows the thread’s known entry direction. Retrieval is straightforward when an end is reachable and the thread is intact, and difficult when it has fragmented or when barbs have engaged the SMAS. Where only the track remains, releasing the tether does more for the patient than any search for a thread that is no longer there.

Injectables of unknown composition

This is the largest single category in practice. The record is gone, the clinic has closed, the product came from abroad, or the injection was given outside a medical setting and the patient was never told what it was. Being unable to name the product does not prevent diagnosis and does not prevent surgery.

What is established instead is the plane the material occupies, how far it extends, whether it has formed nodules or fluid-filled spaces, and how it relates to normal fat and to nerves. Hyaluronidase is used as an indirect test where hyaluronic acid is plausible. CT is added where bone position, wide calcification or traces of previous contouring surgery are in question. Biopsy is considered where imaging and response testing leave the nature of the tissue unresolved.

An operation can be planned on layer and extent without the product name. What cannot be planned without it is the non-surgical route.

02By region

The same material is a different operation in different parts of the face. What changes is not the substance but what surrounds it: how thick the skin is, which nerves run through the region, whether the structure underneath can be replaced if it is damaged, and how visible a small error will be.

Tear trough and lower lid

The skin here is the thinnest on the face. The orbicularis oculi carries vessels and small nerve branches within it, and injected material commonly lies in or against the muscle rather than cleanly above or below it. Superficial hyaluronic acid shows through as a blue-grey shadow. The region moves little and turns over slowly, which is why material persists here long after the same product would have gone elsewhere.

Both errors are visible. Leave too much and the ridge remains. Take too much, or take normal structure with the material, and the lower lid retracts or turns outwards, which is a harder problem than the one the patient came in with. The approach follows from that: a non-incisional route through a small port where the material is soft and close to the lid; a transconjunctival incision where skin laxity does not need correcting; a transcutaneous incision where the material is firm, extends towards the cheek, or where skin has to be addressed at the same time. Material that has encapsulated is not cleared by a cannula alone. The clinic states that infraorbital foreign body removal is performed by Dr. Kang himself.

Forehead, glabella and temple

Material in the upper face is usually old and usually deep. The supraorbital and supratrochlear nerves emerge at the orbital rim. The temporal branch of the facial nerve crosses the zygomatic arch beneath a thin layer of fascia, where it cannot be seen without magnification and cannot be repaired usefully if it is divided. This is the principal region in which an endoscope is used: the access incisions sit inside the hairline, and the nerve is seen rather than inferred.

A long-standing forehead implant adds a second consideration. Over years a space can develop between the implant and the frontal bone, and the bone surface can be eroded. The clinic describes taking CT before removal partly for this reason, because erosion determines how hollow the forehead will look once the implant is out, and that belongs in the consultation rather than after the operation.

Nasolabial fold and cheek

The midface is where repeated treatment accumulates. Filler in the subcutaneous plane, filler on the periosteum, grafted fat in between, often all three placed years apart by different people. The layers overlap and the boundaries between them are the first thing lost. The angular and facial arteries run in this territory, which is why material here is approached in a known plane rather than blindly.

Deep cheek material can frequently be reached through an incision inside the mouth, which keeps visible scarring down. This is also the region where removal changes the face most, and not only by subtraction. Material in the midface conceals descent that is already present, and taking it out reveals what it was concealing.

Chin and jawline

The mental nerve leaves the mandible below the second premolar and supplies sensation to the lower lip and chin. The marginal mandibular branch of the facial nerve runs near the lower border and moves the corner of the mouth. Material injected for chin projection is subject to muscle action with every word spoken, and it can migrate below the mandibular border, where it is felt as a band rather than as the lump it began as.

Soft tissue descent in front of the chin point is often called a witch’s chin. It follows ageing, previous contouring surgery or the effects of injected material, and it can simply be the shape a person was born with. The correction depends on which of those applies, so the first task is to establish the cause rather than to treat the appearance.

Nose

The nasal skin envelope is thin over the tip and its blood supply is unforgiving. Injected material sits in a loose plane in which it spreads readily, and it firms with time. Vascular complications are described after nasal injection because the vessels of the dorsum and sidewall connect with the ophthalmic circulation, and that anatomy does not change with the product used. Material here also constrains what a later operation can achieve, because it alters the tissue that operation would have to work with. Which surgeon takes a given nasal case at this clinic is confirmed at consultation.

Opening is not the hard part. The hard part is deciding how much can come out, what must be left, and which plane to work in.

03Foreign body granuloma

A foreign body granuloma is the tissue’s long answer to something it cannot break down and cannot ignore. Macrophages gather at the material, fuse into multinucleated giant cells, and collagen is laid down around the whole. The result is a firm mass containing the original substance and a good deal of tissue that was not there before. It is not an infection, and it is not the product simply sitting where it was put.

Why it can appear years later

The process is cumulative rather than sudden. Nothing detectable has to happen on the day the lump is noticed; the reaction has been assembling for a long time and has only now reached a size that can be felt. Delayed inflammatory nodules are described from a few weeks after injection to more than a year afterwards, and longer intervals are reported. A person can say, accurately, that they had no trouble at all for five years, and still be describing a reaction to something injected five years ago.

Materials that work by inducing collagen are most often described in this context. Where the collagen response is greater than intended, the clinic’s description is that the excess collagen and the surrounding cells together change into a firm form. Pathology after removal of polycaprolactone-based filler has shown multinucleated giant cells with collagen deposition. Hyaluronic acid and other materials can also provoke a reaction in an individual patient, less commonly, and no material should be assumed incapable of it.

Delayed inflammatory nodule or infection

The two are treated differently, and telling them apart on appearance alone is not reliable. The features below are the ones usually used to lean one way or the other. They are a guide to examination, not a substitute for it.

The two can occur together. A low-grade bacterial film on the surface of implanted material is one proposed mechanism by which a quiet deposit becomes an inflamed one, which means the clean distinction between reaction and infection is sometimes not available. Where infection is clearly active, treating it comes first.

What is described as setting it off

Triggers reported in the published literature for delayed inflammatory reactions after injectable treatment include viral illness, particularly influenza-like and upper respiratory infections; dental treatment; vaccination; facial trauma; and further injection into a site that already contains material. Bacterial biofilm around the implanted substance has been proposed as an underlying mechanism in some of these cases.

These are associations described in case reports and series, not established causes, and the great majority of people who have dental work, influenza or a vaccination while carrying injected material have no reaction at all. The value of the list is that it explains why the timing felt arbitrary, and that it tells the clinician to ask what happened in the weeks before the lump appeared.

What treatment involves

Where inflammation is active, it is settled before anything is removed. The clinic describes a period of medication before proceeding to removal surgery in such cases. Operating through active inflammation, particularly with wide undermining, raises the risk of infection and delayed healing.

Steroid treatment is frequently given elsewhere before these patients arrive, and it often works in the short term. It reduces the inflammation and the bulk. It does not remove the material that provoked either, which is why the same nodule can return once the course finishes, and why several rounds of it can pass before anyone establishes what is actually in the tissue. The definitive step, where the material can be identified and safely reached, is to remove it together with the tissue formed around it. Recurrence remains possible where material has been left behind.

At a glance

Dissolved by hyaluronidase

Hyaluronic acid only. Not polycaprolactone, calcium hydroxylapatite, poly-L-lactic acid, the permanent fraction of collagen-carrier fillers, polyacrylamide, grafted fat or threads.

Fillers the clinic describes as needing surgical removal

Radiesse, Ellansé, Artecoll, Artefill, Sculptra, Aquamid and comparable products.

Removal methods, as the clinic describes them

Cannula aspiration, ultrasonic instrument, endoscope and open incision, used singly or in combination.

Pathology reported after removal

Multinucleated giant cells with collagen deposition, in polycaprolactone-based filler.

Delayed inflammatory nodule, reported onset

A few weeks to more than a year after injection.

What imaging settles

Plane, depth, extent, nodularity, fluid, and relation to normal fat and nerve.

What imaging does not settle

The product name, particularly in old mixtures and advanced fibrosis.

Yes. Semi-permanent and permanent fillers can remain years after treatment, and hyaluronic acid can also persist in this region for longer than its stated duration.

The polymer may have broken down while the fibrous reaction it provoked has not. What is felt in that case is the track rather than the thread, and the two can feel identical.

They adhere strongly to surrounding tissue and remain in the body for a long time, so difficulty tends to increase with the interval since injection. Position and elapsed time matter more than the product name.

Areas hardened by over-grafting or calcification can be broken down selectively with an ultrasonic instrument or removed through an incision. Where the hardened part lies against nerve or muscle, it is not removed in full.

It can, if material has been left behind or the reaction to it persists. This is one reason observation continues after removal rather than ending when the swelling settles.

Imaging patterns, timings and protocols described here are the ones generally described and, where indicated, the clinic’s own account of its practice. They are not a diagnosis. Product identification from imaging alone is unreliable in old and mixed deposits, and what can actually be removed from a particular face is decided on examination and on the anatomy found at operation.ContinueRemovalFacial Foreign Body RemovalMaterial injected into a face does not always answer to an injection that dissolves it. This page sets out how the…RemovalUnder-eye RemovalThe lower eyelid is the thinnest skin on the face and the place where the most has to be left behind. This page sets…RemovalKnowing What Is In ThereMost people arrive without a product name, a receipt or a record. Identification begins instead with what can still…