Safety of Copolyamide Filler Injection for Breast Augmentation

Shunichi Nomoto, MD; Keiko Hirakawa, PhD; Rei Ogawa, MD, PhD, FACS


Plast Reconstr Surg Glob Open. 2021;9(2):e3296 

In This Article


Patient and Copolyamide Filler Injection Characteristics

In total, 29 patients presented to our hospital during the 27-month study period. Their details are shown in Table 2. All patients were female and their average age was 42 (range, 26–61) years. According to the patients, 1 received both Aquafilling/Los Deline and Aqualift/Activegel (these formulations were called Aquafilling and Aqualift); 24 received Aquafilling/Los Deline (23 with the formulation called Aquafilling and 1 with the formulation called Los Deline); and 5 received Aqualift/Activegel (3 with the formulation called Aqualift and 2 with the formulation called Activegel).

The average injected volume was 141.03 (20–250) g for the left breast and 138.96 (0–250) g for the right breast [note that 1 patient (case 1) received a volume of 0 in her right breast; this indicates that only the left breast was treated]. The average duration between receiving the injection(s) and coming to our hospital was 22.1 (0.5–48) months.

Copolyamide Filler Complications

Three patients reported having hypochondralgia, pain/discomfort, and chronic pain at presentation 34, 38, and 33 months after the infusion, respectively. Seventeen of the 29 cases (59%) complained of breast deformity. There were 8 cases of infection (28%). In all cases, local infection at the puncture site and inflammation had spread to the whole mammary gland. Induration was seen in 5 cases (17%) and varied from single large to small lumps. Migration of the filler outside of the breast was rare (4/29, 14%), but these cases had the worst symptoms. In these 4 cases, the filler had migrated to the back and vulva. Seven patients (24%) were asymptomatic but came to our hospital because they had become concerned after hearing a news report that discussed the joint statement of 4 Japanese aesthetic medicine-related societies that called for careful use of Aquafilling/Los Deline.

Treatments Provided in Our Center

We conducted imaging scans in 24 patients (83%): computed tomography (CT) scans were performed in 22 cases and magnetic resonance imaging was performed in the remaining 2 cases. Surgery was performed in 13 cases (45%), 11 patients (38%) were monitored by follow-up, and 1 patient was given conservative treatment.

NMR Analysis of Copolyamide and PAAG Fillers

NMR spectra were obtained for the 2 copolyamide fillers and compared with reference spectral data for PAAG, 2 PAAG fillers (Aquamid and Amazingel), and a commercial PAAG electrophoresis gel (e-PAGEL HR) (Figure 1). The 4 characteristic peaks of PAAG shown by the gray ranges were present in all fillers and the electrophoresis gel. Thus, the copolyamide fillers Aquafilling/Los Deline and Aqualift/Activegel appear to be similar to PAAG and PAAG fillers in terms of composition.

Figure 1.

Proton NMR spectra of the copolyamide and PAAG fillers. The following NMR spectra are shown: ① Los Deline, ② Aqualift, ③ Aquamid, ④ e-PAGEL HR, ⑤ PAAG, and ⑥ Amazingel. The characteristic peaks of PAAG are highlighted in gray. ① to ④ were measured by the FGMAS method, whereas ⑤ and ⑥ were measured by the solution-state method.

Physical Appearance of Copolyamide Filler After Desiccation

When collecting the copolyamide filler samples for the NMR study, a fresh formulation of Aqualift 50 g was opened to extract 1 mL. The bag with 49 g of product was then left open to the air and stored in its box in a room at room temperature for about 3 months. At that point, the components had solidified into a hard resin due to evaporation of the water in the bag (Figure 2). When the weight of the material was measured, it was only 1.19 g.

Figure 2.

Appearance of Aqualift when it was left to dessicate for 3 months. A, The product in the open bag. B, The product had become a hard yellow resin. C, The original weight of the product had been 49 g, but it now weighed 1.19 g.