Case Study: How to Combine Treatments to Improve Scarring

By Dr Sepideh Shahidi / 11 Jul 2023

Dr Sepideh Shahidi describes a case addressing scars using HA fillers and CO2 laser

The prevalence of scarring is incredibly high. One study showed that 48.5% of a group of 11,100 individuals reported having at least one scar on their body.1

The causes of scarring are numerous and diverse; however, the most common cause of facial scarring is acne related (up to 43% of scars), followed by injuries and surgical-related scarring.2

To date, the most common methods of dealing with facial scars have been microneedling or skin peels. Whilst these treatments have proven useful, their results are somewhat limited and require long-term commitment, as well as significant downtime.3

Research has shown that the best format for treating scarring is combination treatment – whether that is combining needling with radiofrequency, peels with platelet rich plasma (PRP) or fillers with laser. By using combination techniques, we can tackle scarring issues from both an immediate and a long-term perspective.4 Stimulating the skin superficially with peels, needling or lasers allows us to physically reduce the appearance of scarring, and the use of heat, plasma or fillers allows us to stimulate the cells into developing collagen and reordering the healing tissues.4

CO2 fractional/ablative laser has been considered the gold standard for scar treatment for years. CO2 wavelength is 10600 nm and works by evaporating the water within the skin and instigating controlled wound healing. It is an ideal laser as we have good control over how much trauma we inflict on the skin, and it has been shown to be extremely effective in stimulating new collagen formation. Using CO2 on a fractional setting also allows us to decrease downtime and minimise potential side effects.5,6

Hyaluronic acid (HA) dermal fillers have been shown to have a positive role in tissue recovery by promoting fibroblast and keratinocyte proliferation and migration.4,7,8 Thus, appropriate fillers can be used following certain treatments to speed up recovery and maximise efficiency.

In this article, I will present a case showing how combining CO2 laser with dermal filler can help improve scarring.

Case study


A 36-year-old female patient with Fitzpatrick skin type III presented to me with an atrophic mature facial scar post-surgical removal of an infantile haemangioma.9 The surgery was carried out when she was five, and the scarring progressively worsened with age. The surgeons had attempted to blend the scar into the nasolabial and marionette lines; however, a very distinct and notable mark was left. The scar measured at 4.5cm, starting from just above the corner of the mouth down to midway of the marionette, on the left-hand side of the face.

The patient was a non-smoker, drinks socially, with no notable medical conditions or medications and no allergies or history of cold sores. She had no previous treatments to address the scarring, but had received laser and HA filler treatments elsewhere on her face.

The patient’s main concern was the depth and severity of the scar, particularly in the marionette region, as she felt it made her look older and harsher. The scar which followed down the corner of the mouth gave a very ‘sad’ looking appearance and she was often asked if she was feeling well. This in turn caused a great deal of psychological distress to the patient.

We discussed at length what she was hoping to achieve as an outcome. She felt the scar was part of her facial characteristics, but just wanted to soften the inferior border of the scar where it was exaggerating her marionette line. We decided to maintain the scar in the nasolabial fold/dimple region and only treat from the corner of the mouth down (marionette region).

I explained the options available for scar treatment, including microneedling, surgery, lasers (CO2 lasers and light) and fillers. The patient did not wish to undergo surgery for a scar revision and was not keen on microneedling due to the lengthy procedure time and required repeated sessions. I had previously obtained good results with similar scars using CO2, and so felt that this would be most beneficial in this case.

As the scar was quite deep, I did not believe that CO2 laser alone would be sufficient to smoothen the surface optimally as we would have to be conservative with the settings to avoid hyperpigmentation.10 I also felt that filler alone would increase the risk of making the marionette fold heavier, and thus worsening the patient’s initial complaint of ‘looking sad’. We decided on a combination approach of CO2 fractional laser and HA filler. The patient was warned of the possible risks of swelling, bruising, hyperpigmentation, lasting erythema and further scarring.


As agreed with the patient, we set to carry out three sessions with CO2 fractional laser at one month intervals, followed by one or two sessions of HA filler (dependent on the results). The initial HA filler treatment was to be carried out on the same day as the third and final CO2 laser session, as they can aid tissue recovery post-treatment.11

The filler to be used on the final session of CO2 was Teosyal Redensity 1. By adding Redensity 1, I was able to speed up the recovery process and improve cellular quality due to its biostimulating feature.6 Following the use of Redensity 1, I chose to layer the scar with Teosyal RHA 2 as I find that RHA 2 provides a good amount of fullness while still being malleable enough to avoid any Tyndall effect. HA fillers also allow the introduction of needling during injection, which has been shown to increase new collagen and elastin fibres, as well as creating an opportunity for scar subcision.12 Studies suggest that scar subcision can provide significant results in lifting the scar by breaking down the fibrous strands which bind it down.13

A patch test was carried out for the CO2 settings one month prior to treatment to ensure that it was safe to treat a larger area. Patch testing is an imperative part of procedure safety, and in my experience avoids long-term damage; it also gives the patient a rough idea of how the skin reacts and how long the downtime will be. Skincare was also kept to a minimum, using only hydrating and protecting products from a week before treatment to avoid any peeling or skin sensitisation.

On the day of the first CO2 treatment, the patient was asked to read and sign the consent form (redone at each visit), well-lit images were taken and the skin was cleaned with Clinisept+ Skin and prepped. We placed 4% lidocaine topical cream for 20 minutes with cling film (to prevent the cream from drying out). The numbing agent was then removed, and the skin was cleaned again with Clinisept+ Skin. The patient was also fitted with eye protection.

The CO2RE laser was used under the fractional resurfacing setting – specifically fusion mode, 30% fractional coverage, 84.9mJ ring energy with 70mJ core energy. A total of three passes were carried out, with the skin wiped and dried between each pass. No cooling was necessary as the patient was comfortable and it was a relatively small target area. A surgical smoke extractor was used to remove any debris or smoke from the procedure.

The advised aftercare included mineral sunscreen SPF 50, a paraffin-based ointment (50 liquid paraffin: 50 soft white paraffin) daily and topical hydroquinone 4% for four weeks at a time. The use of topical hydroquinone was necessary in this case as the patient is skin type III, so to reduce the risk of any post-inflammatory hyperpigmentation, it is advisable to have a strict regime of using hydroquinone post-treatment. The patient was advised to strictly avoid the sun as much as possible between treatments and be very mindful of keeping the skin clean using Clinisept+ Skin or diluted cider vinegar solution to cleanse the treated area.14

During the final CO2 sessions, the target area was also injected with 0.5ml of Redensity 1 once the CO2 treatment had been carried out (with no massaging of the product due to the loss of dermal integrity following CO2). The combination of highly concentrated antioxidants and hyaluronic acid allows for optimised dermal restructuring and recovery to further aid the scar tissue improvement and shorten the downtime.12 The product was placed in small microboluses in the superficial to mid dermal layer in accordance with the Teoxane protocol, and did not require any manipulation.15

One month later, the patient returned for a review and completion of the HA filler procedure. At this visit, I first injected 0.5ml Teosyal RHA 2 directly into the scarred area; the filler was placed as linear threads criss-crossed to build a strong foundation to lift the tissue. I then massaged the filler to ensure no lumps were present, and completed the treatment by placing an additional 0.5ml of Redensity 1 on top.

Following the procedure

The patient returned one month later for a review and was delighted with the results. There was a marked improvement in the indentation of the skin and the shadows created by it. The skin was smoother, with increased uniform tone and texture (Figure 1). All that remains is a faint white line and very mild erythema.

We agreed the patient would return in two months for a final follow-up as studies have shown that optimal dermal remodelling is seen three months post-procedure.13,16 The patient felt that her desired outcome was achieved – she no longer felt limited by her scar, and felt that the psychological impact had been significantly improved.

A combination approach for scarring

The combination of CO2 laser and HA filler (and indirect needling/subcision) was both incredibly effective and efficient in the management of post-surgical scarring. The addition of PRP and microneedling with radiofrequency could potentiate the results by improving the regeneration and rejuvenation of the dermis.

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