The differences between mesh grafts, sheet grafts, and full-thickness skin grafts

Characteristics	Meshed STSG (Thin)	Sheet STSG (Thick)	Full-Thickness Skin Graft (FTSG)
Dermal Content	+	++	+++
Primary Contraction	+	++	+++
Secondary Contraction	+++	++	+
Engraftment	+++	++	+
Durability	+	++	+++
Pigmentation	+++	++	+
Resist Desiccation	+	++	+++
Recipient Bed	+	++	+++
Appearance	+	++	+++

Characteristics	Meshed STSG (Thin)	Sheet STSG (Thick)	Full-Thickness Skin Graft (FTSG)
Dermal Content	Contains the epidermis and a thinner layer of dermis, allowing it to be more pliable and conformable to irregular wound surfaces.	Contains a thicker layer of dermis compared to meshed grafts, providing a better cosmetic match and more resistance to trauma.	Composed of both the epidermis and the entire dermis, preserving more of the original skin structure, including sweat glands and hair follicles.
Primary Contraction	Experiences moderate contraction upon application due to the elastic properties of the skin.	Contracts slightly less than thin grafts because the additional dermal content provides more stability.	Exhibits the most significant contraction due to the full dermal layer which tends to shrink when healing.
Secondary Contraction	Tends to contract significantly during the healing process, which may lead to a tighter and less flexible wound area.	Exhibits moderate secondary contraction, resulting in a balance between flexibility and stability of the graft.	Has minimal secondary contraction, maintaining the most original size and shape after healing.
Engraftment	Has a high rate of successful attachment to the recipient site, as the mesh allows for excellent integration with the underlying tissue.	Has a good engraftment rate, though slightly lower than thin grafts due to the decreased surface area contact.	May have a lower engraftment rate than thinner grafts because it requires a well-vascularized recipient site.
Durability	Less durable compared to thicker grafts, suitable for areas that will not undergo significant abrasion or trauma.	More durable than meshed grafts and can withstand more wear and tear.	Most durable and best suited for areas of the body that are subject to frequent movement or forces.
Pigmentation	May initially match the surrounding skin well but can undergo changes like hyperpigmentation or hypopigmentation over time.	Offers a good match to the surrounding skin and may have less pigmentation change than meshed grafts.	Provides the best color match to the surrounding skin, with the lowest chance of pigmentation changes.
Resist Desiccation	Less resistance to drying out; the graft may require more frequent dressing changes or special care to prevent desiccation.	Better resistance to drying out compared to thin grafts, offering a balance between maintenance needs and durability.	Offers the best resistance to drying out, which can be beneficial in areas without frequent dressing changes.
Recipient Bed	Requires a well-prepared recipient bed but can tolerate some irregularities due to its flexibility.	Requires a recipient bed that is well-vascularized and relatively flat for optimal attachment.	Demands an excellent recipient bed with optimal vascularization and contour for successful transplantation.
Appearance	Can have a noticeable mesh pattern, which may be visible even after healing, leading to a less desirable cosmetic outcome.	Provides a smooth, continuous skin surface that can lead to a more cosmetically appealing result.	Offers the best cosmetic outcome, closely resembling the appearance of normal, uninterrupted skin.

Skin grafts are a crucial component in the management of large wounds, burns, or areas of extensive skin loss due to various conditions. Here are the types and subtypes of skin grafts used in reconstructive surgery:

• Split-Thickness Skin Grafts (STSGs)

• Thin STSGs: Include the epidermis and a small portion of the dermis. They are more likely to survive transplantation because they have a higher chance of revascularization.

• Intermediate STSGs: Contain a larger portion of the dermis, offer better durability and less contraction but require a well-vascularized recipient bed.

• Thick STSGs: Comprise almost the entire dermis, providing the best cosmetic result and durability, but have the highest requirement for a well-vascularized bed for graft take.

Modification of STSGs

Meshed grafts and sheet grafts are subtypes of Split-Thickness Skin Grafts (STSGs). They both involve the same type of graft, which includes the epidermis and a portion of the dermis, but they differ in their preparation and application:

• Meshed Grafts have been altered by making multiple small incisions to create a mesh-like pattern. This modification allows the graft to be expanded to cover a larger surface area and provides spaces for fluid egress, which can be particularly beneficial for wounds with a lot of exudate.

• Sheet Grafts are STSGs that are left intact as a whole sheet without the mesh-like pattern. These grafts are typically used for areas where a better cosmetic result is desired, as they heal with a smoother surface compared to the mesh pattern of the meshed grafts. However, they are limited by the size of the wound they can cover since they cannot be expanded.

Why the division is made differently

The division into different subtypes of split-thickness skin grafts (STSGs) and the categorization based on modifications such as meshed and sheet grafts are based on different criteria that serve particular needs in wound management and reconstruction.

Here's why the division is made differently:

1. Thickness of STSGs (Thin, Intermediate, Thick):

• This classification is based on the depth of skin layers included in the graft. It determines the graft's characteristics like flexibility, durability, ability to conform to the wound bed, and cosmetic outcome.

• Thin grafts are more pliable and can take on complex surfaces, intermediate grafts offer a balance between take rates and cosmetic outcome, and thick grafts provide the best durability and cosmetic resemblance to normal skin but require a highly vascular wound bed for successful take.

1. Modification of STSGs (Meshed, Sheet):

• This categorization is based on the processing of the graft after harvesting. Meshed grafts are altered to create a mesh-like pattern which allows them to expand, cover larger wound areas, and facilitate fluid drainage.

• Sheet grafts are left intact and are typically used where a more aesthetically pleasing outcome is desired, such as on the face or hands.

These distinctions allow for a tailored approach in reconstructive surgery:

• Meshed grafts are preferred for large or irregular wounds where expansion and fluid management are critical.

• Sheet grafts are chosen for smaller wounds or when a better cosmetic result is essential.

• Thickness-based grafts are selected according to the specific requirements for graft survival, wound bed characteristics, and desired functional and cosmetic outcomes.

In clinical practice, the decision to use a particular subtype of STSG is based on the surgeon’s assessment of the wound, the patient's overall health and preferences, and the ultimate goals of wound closure and healing.

• Full-Thickness Skin Grafts (FTSGs)

• Taken from areas where the skin is loose and redundant, such as the groin, the upper eyelid for lower eyelid reconstruction, or behind the ear for facial reconstruction.

• Benefits: They provide better cosmetic results as they have a full dermal layer, leading to less secondary contraction and a better color match.

• Challenges: Require meticulous surgical technique to prevent fluid accumulation under the graft, and they demand a very well-vascularized wound bed for successful grafting.

• Composite Grafts

• Contain skin and other tissues such as fat, cartilage, or mucosa.

• Commonly used for the reconstruction of the nose and ears because they provide both skin coverage and structural support.

• Cultured Epithelial Autografts (CEAs)

• Produced by growing epidermal cells in a lab to create sheets of epithelium.

• Mainly used for patients with extensive burns when there is not enough unburned skin to harvest for grafts.
  

Types Based on Donor Source:

• Autografts: Skin taken from another part of the patient’s body.

• Allografts: Skin taken from a donor of the same species (cadaveric skin).

• Xenografts: Skin taken from a donor of a different species, such as pigs (porcine skin).

Graft Selection Factors:

• Wound Characteristics: Size, depth, and location.

• Patient Factors: Age, health status, and presence of comorbidities.

• Desired Outcome: Functional requirements and cosmetic considerations.

For each type of graft, the surgical technique is crucial for success, including proper wound bed preparation, graft application, and post-operative care to prevent infection, ensure graft adherence, and promote healing.