Single-Modality Treatment Failure in Mixed Scar Morphology: The Case for Multimodal Protocols

Single-modality treatment failure in mixed scar morphology often becomes obvious when one treatment improves part of your acne scars, but leaves the rest behind.

This happens because mixed scar patterns do not behave as one problem. A treatment that helps surface texture may not release tethered scars, while a method that targets depth may not soften edges or improve pigment changes.

In this article, you will learn why mixed scar patterns rarely respond fully to one approach, and how combined protocols are designed to target different scar features more precisely.

Let’s break it down clearly.

What Single-Modality Treatment Means

Single-modality treatment means relying on one treatment method on its own to improve acne scars, instead of combining it with other approaches.

In acne scar treatment, this often means repeating one procedure, such as laser resurfacing, microneedling, subcision, or TCA CROSS, as the main plan. That can make sense in some cases, especially when the scars are mild or more consistent in type. 

The difficulty starts when the scars are mixed. Some may be tethered, some may be deep and narrow, and others may sit more at the surface. That is where one-treatment plans can start to fall short. A treatment may help one part of the scar pattern, but leave another part largely unchanged.

Limitations of Common Monotherapies

No single treatment can do every job equally well. Each one has a more specific role, which is why results can look noticeable in one area but incomplete overall when scar patterns are more complex.

Here are the limitations of common monotherapies:

• Laser resurfacing may improve surface texture, scar edges, and overall skin smoothness, but it may not release tethered scars beneath the skin.
• Microneedling can support collagen remodelling and improve mild textural changes, but it may not be enough for deep, sharply defined, or heavily tethered scars.
• Subcision can release fibrous bands and help lift rolling or bound-down scars, but it may not smooth the skin surface or fully soften visible scar edges.
• TCA CROSS, or trichloroacetic acid chemical reconstruction of skin scars, can help selected deep and narrow scars, especially ice pick scars, but it does not treat broader uneven texture across a larger area.
• Radiofrequency-based treatments may support collagen stimulation and textural improvement, but they may still fall short when scars need mechanical release or more focal correction.
• Pigment-targeting treatments may reduce visible post-acne marks, but they do not correct depressed scars, tethering, or uneven skin contour.
• Regenerative support treatments may help improve healing or overall skin quality, but they do not replace the structural role of release, resurfacing, or targeted scar correction.

5 Reasons for Single-Modality Treatment Failure in Mixed Scar Morphology

Single-modality treatment can fall short when acne scars are made up of more than one structural problem. That is often the case in mixed scar morphology, where different scar types sit side by side and respond differently.

Below are the main reasons for single-modality treatment failure in mixed scar morphology:

1. Different Scar Types Do Not Respond the Same Way

Rolling scars, boxcar scars, and ice pick scars may exist together, but they behave very differently.

• Rolling scars are often tethered beneath the skin.
• Ice pick scars are narrow and deep.
• Boxcar scars tend to have broader edges and defined borders.

Clinical observations show that most patients present with more than one scar type, rather than a single uniform pattern. This makes it difficult for one treatment to fit all scars equally well.

2. Surface Improvement Does Not Always Mean Structural Change

The skin can look smoother after treatment, but that does not always mean the deeper issue has been corrected.

For example, resurfacing treatments may reduce contrast and improve texture. However, if the scar is still anchored underneath, the indentation may still be visible under certain lighting. This is why early improvement can sometimes plateau.

3. Scar Depth and Shape Vary Across the Same Face

Not all scars have the same depth, width, or edge shape. Some are shallow and broad. Others are narrow and sharply defined.

A treatment that works reasonably well for one type may not produce the same result for another. This variation makes uniform improvement difficult with a single modality.

4. Texture, Pigment, and Redness Are Different Problems

Acne scars are not always just about texture.

Some patients also have:

• post-inflammatory hyperpigmentation (dark marks)
• post-inflammatory erythema (persistent redness)

These are separate concerns. Treating texture alone does not always improve colour changes. In darker or Asian skin types, pigment-related concerns can be more noticeable, which further highlights the limits of single-modality treatment.

5. Partial Improvement Can Be Misinterpreted as Failure

Sometimes a treatment has worked, but only partially. For example, texture may improve by 30 to 50 percent, which is a range often reported in clinical settings for certain monotherapies. However, if deeper scars remain, the overall result may still feel unsatisfactory.

This can lead to the impression that the treatment failed, when it actually addressed only part of the problem.

How Multimodal Protocols Address Mixed Scar Morphology

Multimodal protocols are used because mixed acne scars usually do not come from one problem alone. What you see on the surface may include several things happening at once: tethering under the skin, uneven texture, deep narrow scars, broader depressed scars, and post-acne marks.

A single method may help one part of the scar pattern, but leave the rest looking much the same. For example, a treatment that improves surface texture may not release bound-down scars. A treatment that helps deep narrow scars may do very little for wider textural unevenness. 

This is why multimodal treatment is often less about doing more and more about treating the right problem with the right tool.

In practical terms, that may mean one step is used to release tethering, another to refine texture, and another to target deep focal scars or lingering marks. The aim is not to stack treatments for the sake of it. The aim is to build a plan that matches how the scars actually behave.

What Clinical Studies and Comparative Findings Suggest About Combination Treatment

The evidence does not point to one simple message like “one treatment never works”. The more useful takeaway is this: when scars are mixed, combination approaches often make more sense because they are better matched to the problem in front of you.

One study compared fractional carbon dioxide laser alone with fractional carbon dioxide laser combined with subcision, and found greater improvement in the combined group within the study setting. What is especially relevant is that the authors pointed out how varied acne scar morphology can be, which helps explain why a single treatment often has limited reach.

A larger retrospective study involving 413 patients found stronger improvement when fractional carbon dioxide laser was combined with subcision than when laser was used alone. That is useful because it moves the discussion beyond theory. It suggests that in real clinical settings, combining release with resurfacing can produce a more complete result than resurfacing by itself.

Another useful point is that the order of treatment can matter too. A 2024 study compared simultaneous and sequential use of fractional carbon dioxide laser with subcision. That supports an important idea in multimodal planning: it is not only about which treatments are chosen, but also when and how they are used together.

Studies have reported better outcomes when fractional carbon dioxide laser is combined with platelet-rich plasma rather than used alone. Again, that does not mean every patient needs the same combination. It simply supports the broader principle that layered scar problems often respond better to layered treatment plans.

Common Multimodal Treatment Combinations for Acne Scars

When acne scars are mixed, treatment is often planned as a combination rather than a single method.  Each approach targets a different part of the scar pattern. 

Below are some common multimodal treatment combinations:

1. Subcision With Energy-Based Resurfacing Treatments

(Subcision + EdgeOne Fractional CO2 / Pico Laser / INFINI Fractional RF)

This combination is often used when scars are both tethered and uneven.

• Subcision helps release bound-down scars. Once that tension is reduced, resurfacing treatments can work more effectively on texture and edges.
• Fractional CO2 laser is commonly used for surface refinement.
• Pico laser may help with texture and pigment.
• Radiofrequency-based treatments can support deeper collagen remodelling.

2. TCA CROSS With Global Skin Texture Refinement

(TCA CROSS + Pico Laser / Fractional CO2)

TCA CROSS is used for deep, narrow scars such as ice pick scars. It works in a very targeted way, treating individual scars.

Because it does not address the surrounding skin, it is often paired with resurfacing. This helps improve overall texture and reduces contrast between treated and untreated areas.

3. Radiofrequency-Based Collagen Stimulation in Combination Protocols

(INFINI Fractional RF + EndyMed Nano-Fractional Radiofrequency)

Radiofrequency-based treatments are often used to improve skin structure gradually. Combining approaches within this category may help target both superficial and deeper layers. 

This is usually considered when the focus is on texture and skin quality rather than deep tethering alone.

4. Needle-Free or High-Pressure Delivery Combined With Structural Treatments

(Enerjet 2.0 with subcision or resurfacing treatments)

High-pressure delivery systems are sometimes used alongside structural treatments. They may support skin response or delivery into the skin, but are usually not relied on alone when deeper correction is needed. 

Combining them with subcision or resurfacing helps address both structure and skin quality.

5. Regenerative Support as Part of Multimodal Protocols

(Rejuran S alongside structural or energy-based treatments)

Regenerative treatments are often added to support healing and improve overall skin quality. They are typically used alongside other treatments rather than on their own, especially when structural changes are needed.

6. Layered Protocols Within a Structured Acne Scar Programme

(360° Acne Scar Treatment Program as an example of staged, multimodal planning)

Multimodal treatment is often done in stages rather than all at once. One phase may focus on release, followed by texture refinement, then further adjustments based on how the skin responds. This allows each step to build on the previous one.

That is often where a structured, layered approach becomes more effective than repeating a single treatment.

Clinical Assessment Before Choosing a Multimodal Approach

Clinical assessment matters because multimodal treatment only works well when it is built around the actual scar pattern, not just a general label like “acne scars”.

Mixed scar morphology can include rolling scars, boxcar scars, ice pick scars, tethering, uneven texture, and post-acne marks on the same face. These do not respond in the same way. If they are treated as though they are one uniform problem, the plan can easily become too broad or too limited.

A proper assessment helps answer a few important questions early:

• which scars are tethered
• which scars are deep and narrow
• which scars are broader and more textural
• which concerns are structural scars, and which are pigment or redness
• which issues should be treated first, and which can be addressed later

That is what makes assessment so important before choosing a multimodal approach. It shapes the sequence, the combination, and the overall direction of treatment.

At Sozo Clinic, this assessment is used to map out the scar pattern in a more detailed way before deciding on a treatment plan. The focus is not only on how the scars look straight on, but also on how they behave under angled light, how deep they sit, whether they are bound down, and whether colour changes are adding to the overall uneven look.

This is where Dr. Justin Boey’s role becomes especially relevant. Acne scar treatment depends heavily on judgement. It is not just about knowing what each treatment does, but knowing when it fits, where it fits, and what it still cannot do on its own.

Dr. Boey is the Medical Director of Sozo Clinic. He holds an MBBS from the National University of Singapore and Ministry of Health-approved Certificates of Competence in Aesthetics. His experience allows him to assess scar patterns more carefully and guide you towards a multimodal treatment plan that matches your skin, scar depth, and overall scar profile.

Conclusion

Single-modality treatment failure in mixed scar morphology does not always mean a treatment has failed completely. More often, it means one method improved one part of the scar pattern, while other features remain visible.

That is why mixed acne scars often need a more layered plan. Rolling scars, boxcar scars, ice pick scars, tethering, and post-acne marks do not behave the same way, so they rarely respond fully to one approach alone.

A more thoughtful treatment plan starts with understanding what each scar is doing before deciding what to use and in what order.

If your acne scars seem stuck despite treatment, book a consultation with Sozo Aesthetic Clinic to find out what your scar pattern may actually need.