The Crucial Role of Mechanical Forces in Wound Healing and Scar Minimisation

Every year, millions of people experience skin injuries due to surgery, trauma, or burns.

Scar formation is a natural and inevitable result of wound healing, but can also lead to compromised skin function, disfigurement, and various psychosocial challenges.

Understanding and mitigating excess scar formation is of paramount importance in allied health care, and MLD and Elastic Taping are two of the most effective modalities in your scar management tool box.

The Complex Process of Scar Formation

Scar formation is a complex biological process involving various factors including cellular activities and chemical signals. There are four main stages;

Haemostasis: platelets form a clot to prevent further blood loss, and the pre-cursors to collagen formation enter the tissues.

Inflammation: brings in all the necessary immune cells to get rid of any invading microorganisms and organise the clean up.

Proliferation: reticular collagen is laid down to repair the tissue structure and as a template for the final stage.

Remodelling: functional reorganisation of collagen fibres.

Complex chemical signalling co-ordinates the cellular activity and transition between stages during wound healing. Key elements in how a scar forms include how fast cells reproduce and proliferate, and what kind of chemical factors are being released,

Mechanical forces acting on the wound site play a significant role in determining these cellular and molecular responses, and therefore the nature of the resulting scar. Stress, shear and compression forces can have beneficial or detrimental effects on scar formation depending on the type of force and stage of healing (1).

The Impact of Mechanical Forces on Scar Formation

Mechanical forces affect wound healing through a process called mechano-transduction, cellular and molecular responses to mechanical changes in the scar environment which can activate, suppress, or modulate cellular activities and chemical signals.

Fibroblasts and keratinocytes are crucial for wound healing.

They are mechano-reactive and mechano-responsive, which means that they sense mechanical stress and respond by activating a protein called FAK to promote cell adhesion, migration, and collagen accumulation.

Molecular responses to mechanical forces include regulation of cell proliferation and tissue regeneration by controlling gene expression, therefore high mechanical stress will increase the likelihood of significant scarring. (1).

Likewise too much mechanical stress on a healing wound will increase FAK and promote the formation of fibrosis (2)

Figure from (Zhou et al, 2023)

Therapeutic Approaches Using Mechanical Regulation

Given the influence of mechanical forces on scar formation, therapeutic strategies often focus on modulating these forces to minimise scarring (1). The aim of these therapies is to reduce mechanical tension on the healing scar, and promote the functional formation of scar tissue.

Manual Therapies

Therapists may manipulate the skin and tissue surrounding an acute scar, and the scar itself in healed scars, using a variety of modalities and techniques.

From very gentle movement of the skin adjacent to an unhealed scar, to uncomfortably strong forces applied to soften stiff and contracted scars, the pressure, direction and force applied will be determined by the stage of healing.

Applying the correct type of mechanical force at each stage can promote wound healing and progress the scar formation though the necessary stages.

However too much mechanical stimulation too early can initiate a new unwanted inflammatory action, taking the tissue back through the earlier stages of healing and potentially increasing collagen deposition.

Manual Lymph Drainage

The Dr Vodder method of MLD directly induces mechano-transduction through precise manipulation of the skin and underlying tissue at specified pressures and directions according to lymph flow and skin elasticity.

Stationary Circles create gentle stretch and shear forces in the skin and underlying tissue.

By applying the ideal type of mechanical stress to healing tissue, MLD takes advantage of the natural healing processes, amplifying ones that promote wound healing and scar management while minimising those that don't.

MLD can be used in the acute phase of healing to promote new capillary and lymph vessel growth.

Continued through the inflammatory phase MLD will promote the natural progression to the proliferation phase, minimising excess collagen production.

In the remodelling phase, firmer MLD techniques work directly with the normal functional range of the collagen and elastin fibres to promote the formation of a soft and mobile scar.

Topical Therapies

From bandaids to high tech mechanical suction devices, the first response to many new wounds is to cover them. Topical dressing and devices have a variety of uses, from keeping the wound and surrounding skin clean, to delivering bio-active molecules and chemicals into the wound.

Paper (inelastic) tape is used post-surgically to minimise tension at the wound site, reducing the chance of pathological scarring by limiting the mechanical stress on the healing tissue.

When used consistently and for prolonged periods this method will help to improve scar appearance and reduce hypertrophy and is particularly useful in high stress areas such as over the knee joint.

Silicone gel sheets provide a protective barrier and reduce mechanical tension at the wound site.

Silicone treatments work by hydrating the stratum corneum and downregulating some growth factors thereby reducing collagen deposition and scarring.

Compression Therapy over the scar and surrounding tissue reduces capillary perfusion pressure and promotes collagen matrix maturation. The increased tissue pressure interrupts the formation of fibrotic tissue, helping to flatten and soften the scar.

Compression garments can be highly effective in controlling scar remodelling and reducing overall scar size and are used extensively in burns therapy.

Table from (Zhou etal, 2023)

Elastic Therapeutic Tape

Elastic tape can be applied at every stage of wound healing to reduce tension from multiple angles, and improve circulation and lymph drainage. In later stages tapes can be positioned to encourage functional rehabilitation of tissue structure, and can be used as a targeted form of spot compression.

In the early phase of wound healing we use lymph tapes to support circulation and lymph formation, using single strips placed parallel to the scar to reduce mechanic tension around the wound.

During the proliferation phase we use cross tapes over the scar to moderate the amount of pre-cursor collagen that is deposited.

In the remodelling phase, scar tapes will help to moderate the external mechanical stimulation and support functional remodelling.

The following video is an excerpt from a presentation on mechanical forces, lymph angiogenesis, scar formation, and elastic taping. View the full video in the Members Forum

Future Directions in Scar Management

As our understanding of scar formation and the role of mechanical forces continues to evolve, the integration of advanced therapeutic methods is becoming increasingly important. Manual lymph drainage and elastic therapeutic tape represent promising tools in this domain, offering an alternative to more invasive and sometimes uncomfortable techniques like aggressive massage and shock wave therapy.

Minimising mechanical tension at the wound site is crucial for enhancing wound healing and mitigating scar formation. MLD and Elastic Taping can offer superior results by providing a gentler, more targeted intervention compared to traditional approaches that may be painful or less effective. The complementary nature of their principle of application and physiological effects make them synergistic partners in scar minimisation.

Future studies should focus on determining the optimal parameters of mechanical interventions, such as the appropriate duration and intensity of applied forces, and understanding their impact on cellular and molecular responses.

Once we know these parameters, I predict that we will discover that the forces used in Manual Lymph Drainage (MLD) and Elastic Taping Therapies at each stage of healing, will align with the optimal ranges of stress, shear, and compression forces required for optimal healing and scar formation. Confirmation what we have seen for decades in our clinics.

Dr Vodder's MLD supports healthy wound healing and helps to minimise scar formation

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1. Zhou S, Xie M, Su J, Cai B, Li J, Zhang K. New insights into balancing wound healing and scarless skin repair. J Tissue Eng. 2023 Jul 27;14:20417314231185848. doi: 10.1177/20417314231185848. PMID: 37529248; PMCID: PMC10388637. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10388637/
   

2. van Daele, U.; Meirte, J.; Anthonissen, M.; Vanhullebusch, T.; Maertens, K.; Demuynck, L.; Moortgat, P. Mechanomodulation: Physical Treatment Modalities Employ Mechanotransduction to Improve Scarring. Eur. Burn J. 2022, 3, 241-255. https://doi.org/10.3390/ebj3020021