Social media has created an uprising desire to aim for aesthetic perfection. Filters and photo editing apps suggest that we can improve ourselves with just one click.
Lately, soft tissue fillers are on the rise supplanting in many situations more invasive procedures such as surgery (Melo et al, 2017).
One of the areas that have not been exploited with the use of medical-grade soft tissue fillers for its anatomical location and extension is the gluteal area.
Usually, there are two types of dermal fillers in the market: biodegradable fillers, such as hyaluronic acid (HA) and biodegradable collagen stimulators such as calcium hydroxyapatite (CaHa) and polycaprolactone (PCL), and non-biodegradable fillers such as polymetilmetacrylate (PMMA) (Jongseoo et al, 2014).
Minimally invasive treatments to achieve the perfect buttock have been requested by patients for decades. However, with multiple complications such as product migration, nodules or granulomas that took place with the use of silicone and other non-absorbable products to achieve these results, it became a surgery only answer. However, with all the minimally invasive procedures on the rise, a new field for minimally invasive body shaping emerges from its latent state. (Chacur et al, 2019).
Nowadays, besides surgical options, such as silicone implants or the famous Brazilian butt lift, which involves an autologous fat transfer, the only available non-surgical treatments for gluteal augmentation are the injection of biocompatible fillers, such as large quantities of hyaluronic acid or biostimulation of the area with polylactic acid (PLA) or even the use of non-absorbable fillers like PMMA. Nevertheless, these minimally invasive treatments have their limitations such as the potential risk for migration of product, foreign body reaction or the cost of the treatment (Chacur et al, 2019).
In the quest to find a better option to treat this specific area, the idea of using PCL to enhance the gluteal area emerged.
PCL is a state-of-the-art soft tissue filler and collagen biostimulator. This PCL-based filler with European quality standards (CE) is well-known for decades of presence in the medical field, and just a little over 10 years in the medical aesthetics field with notorious results. It was introduced in the medical aesthetics market in 2009 and is nowadays available in 80 countries (Melo et al, 2017).
This biocompatible product is made of a carboxymetilcellulose (CMC) gel, carried with polycaprolactone microspheres with a particle size of 25-50 micrometres, small enough to be phagocyted by the macrophages and have the property of biocompatibility. All presentation comes in 1 ml prefilled, ready-to-use syringes (Marion et al, 2013). Even though biostimulators share some characteristics, such as particle size, distribution and concentration, PCL has controlled and even hydrolysis superior bioreabsorption qualities, in comparison to its competitors such as CaHa and PLA (Marion et al, 2013).
On the other hand, CaHa does not have presentations that could last up to 3 years and PLA cannot give immediate results because is not suspended in a volumising gel carrier. PCL is indicated to increase volume and reshape the face, as well as biostimulate the skin and subcutaneous tissue. It has also been used to treat skin laxity on the neck and hands, yet there is little to no information regarding this filler and its potential use in the gluteal and trochanteric area (Marion et al, 2013).
Case report
A case of a 26-year-old woman who was searching for a non-surgical option to give projection and increase perkiness in the gluteal area is presented in Figures 1, 3 and 4. She had a history of two gluteal fat transfers in 2014 and 2016, respectively, with no satisfactory results.
Figure 1. The patient pre-treatment 
Figure 2. How the patient was marked 
Figure 3. The patient immediately post-treatment 
Figure 4. The patient 3 months post-treatment
After explaining the potential achievable outcome using PCL as a filler and biostimulator, the patient agreed to be treated with it.
After all the consent forms were signed, baseline pictures were taken (Figure 1). The patient was prepped and marked with two centrifugal radial vectors, the first one starting from the upper transgluteal line, and the second one from the upper external area, making sure some of the lines from both vectors could cross paths (Figure 2).
After marking the treatment area, and before injecting 2% lidocaine in both vector entry points, it was disinfected with 1% chlorhexidine.
Using a 22 Gx60 mm cannula, two 1ml syringes were injected per side, following the markings and respecting the correlation of 1 ml per 10x10 cm area. The injection technique was retroinjection of 0.2 ml per line in the subcutaneous tissue. After the injections, a rough massage was performed in the area to ensure even distribution and ensure there were no residual lumps or nodules.
The immediate results were evaluated after the treatment was completed, and photographic evidence using a white backdrop (Figure 3) demonstrated an enhancement in both volume and shape.
The patient was sent home with specific instructions, such as no exercise or manipulation of the area and sleeping on her front to avoid excessive compression of the gluteal zone.
After 3 months, there was a control appointment where further photos were taken (Figure 4). The patient referred in the same subjective treatment satisfaction test previously applied an overall 9/10 satisfaction score.
Photos show that there was a slight shape remodelling compared with photos taken immediately after treatment; yet, an outstanding result, compared with the baseline picture, remained.
Discussion
The use of biostimulators to enhance the buttock area has become a new treatment possibility for patients who do not want to undergo a surgical procedure (Chacur, 2019).
There is no report in the literature that PCL has been used in the buttock area; however, it is being reported in different body areas, such as the hands, abdomen and knees. The reason might stem from the belief that large quantities of such products are needed to create a projection in the gluteal zone. However, PCL comes in a prefilled ready-to-use 1 ml syringe and, according to the designed protocol, 1 syringe can treat an area of up to 10x10 cm. To ensure results, there is no need to hyperdilute the material. In some cases, it could be mixed with up to 0.2 ml of 2% lidocaine to ease the discomfort of the injection (De Melo, 2012).
The advantage of using a PCL-based filler is that, in comparison with CaHa, there is no need to hyperdilute, which simplifies the treatment protocol (Trinidad de Almeida, 2018).
In comparison to PLA, PCL provides immediate results and there is no need to perform serial sessions to achieve an enhanced buttock projection (Lin, 2019).
In the case study, the patient wanted a gluteal projection that was not obtained in the previous BBL procedures she underwent. The main issue was the lack of projection in the area.
A PCL-based filler was suggested, as she was a young patient with no signs of menopause, who actively exercised and had a body mass index lower than 27.
The reason why vectorial injections helped in this case is because of the increased volume that mesh patterns produce in the subcutaneous tissue. The use of PCL without hyperdiluting helps to keep the technique simple and avoids tampering with the molecular structure of the filler. It also ensures that the results will last as long as the product description promises.
As shown in Figure 3, there is a significant improvement in the projection of the gluteal zone, both in shape and texture. The areas that had a mild depression were partially filled up and the dusky colour of the skin improved. The result of this overall improvement is due to the new type I collagen formation. After the 3-month evaluation, the patient was asked if she wanted to add 1 ml more of PCL filler per side to further project the area, but the patient assured she was happy with the results.
Conclusion
In conclusion, a knowledge gap is found when discussing which buttock filler is right to use. More research is required within this area of medical aesthetics. Meanwhile, using PCL filler could become a new alternative to non-surgical gluteal enhancement. It is a simple, ready to use, minimally invasive procedure that provides great results. The main difference is that there is no need to use a large amount of product to achieve immediate and long-lasting effects. Lastly, because of the collagen biostimulation property, the treatment will also enhance the skin quality, giving the buttocks an overall and satisfactory improvement.
Key Points
- Buttock enhancement is in fashion
- Minimally invasive procedures are requested more often
- There is little information regarding appropriate fillers for the buttock area
- Polycaprolactone based filler is a potent biostimulator
- Polycaprolactone could be used in the gluteal area.
CPD reflective questions
- What is the particle size of a biostimulator molecule?
- What is the polycaprolactone gel carrier made of?
- Does polycaprolactone needs to be diluted?