**2. Cryopreserved total skin cutaneous allografts (CTSCAs)**

CTSCAs emerge from the need and search for coverage for burnt patients and complex wounds associated with a low organ and tissue donation rate. Compared to the classical SAs, CTSCAs have three distinctive features: a) derived from live donors, b) total thickness skin, and c) cryopreserved [20, 21].

#### **2.1 Live donors**

It is crucial to emphasize that the skin donation request is done in the context of elective surgery and happiness due to the primary esthetic and functional expected results and not in an environment of familiar sadness of skin procurement in cadaveric donors, where the donor remains with a social altruism sensation secondary to the donation of a tissue that would otherwise be a surgical waste. The extensive inclusion and exclusion criteria for skin donation in cadaveric donors (**Table 1**) in order to guarantee the microbiological safety of the tissues are left aside in live donors, since it is understood that patients submitted to elective body contour surgeries do not have contraindications for the performance of such surgeries and the consequently tissue donation.

*Banks of Cryopreserved Skin from Live Donors and Total Skin Allografts in the Surgery of… DOI: http://dx.doi.org/10.5772/intechopen.104451*


#### **Table 1.**

*Exclusion criteria for skin donation.*

Besides, there are multiple myths around the organ and tissue donation process; thus, the skin procurement in live donors permits the breakdown of two important myths: a) cadaveric body disfigurement secondary to the skin extraction, a factor that affects the low skin donation rates in many countries, which becomes a "refinement" obtained after a body contour surgery, and b) poor patients donate their tissues and organs to wealthy patients, since people with higher incomes have more access to body contour surgeries and burns are more common in the poor population [22, 23].

### **2.2 Total thickness skin**

Skin resection in body contour surgeries allows the procurement of a cutaneoussubcutaneous flap, which is defatted with scissors, obtaining total skin cutaneous allografts (TCSAs) (**Figures 1** and **2**) compared to classical SA, which are procured with a dermatome, obtaining only partial skin allografts. The amount of TCSA obtained is variable. In an adult abdominoplasty, 3–4% of the total body surface is resected, and once the skin is processed, the valuable surface is of approximately 250–300 cm<sup>2</sup> . The skin surface obtained is more extensive in patients submitted to body contour surgeries post-bariatric surgery. However, histologically, the skin presents chronic inflammation areas, sebaceous gland infections, lower collagen fiber organization, elastin and fibroblast concentration, and metalloproteinase levels similar to oncologic or burnt patients [24, 25].

Even if the skin surface obtained compared to a cadaveric skin procurement is smaller, its potential is associated with the number of patients submitted to these

**Figure 1.** *Abdominal cutaneous-subcutaneous flap.*

*Banks of Cryopreserved Skin from Live Donors and Total Skin Allografts in the Surgery of… DOI: http://dx.doi.org/10.5772/intechopen.104451*

**Figure 2.** *Procurement of total skin with scissors from redundant adipose skin flap.*

types of surgeries and the possibility of obtaining all the skin layers, making it an attractive option [26, 27].

#### **2.3 Cryopreservation**

There are multiple forms to preserve tissues: high-concentration glycerol and cryopreservation are the most used techniques in skin banks [28, 29]. The main difference among both techniques is that in the first case, the tissue is nonviable but maintains its structural and mechanical properties, generating a biological dressing. In contrast, the second preserves some cellular viability, and the tissue can be integrated into a wound bedding.

Preservation with high-concentration glycerol is the predominant method in most skin banks since its lower cost and easier storage and distribution. Cryopreservation freezes the TCSA in the presence of a cryoprotectant (glycerol 10%), which prevents the crystallization effects, maintaining the viability of keratinocytes, fibroblasts, endothelial, and Langerhans cells over the time following the freezing. The viability of the obtained tissues is crucial for the clinical results [30–34].

Dimethyl sulfoxide (DMS) is another cryoprotectant frequently used in cryopreservation procedures; however, there are contradictory publications regarding the best alternative for cryopreservation compared to glycerol 10% [35–36].

Precisely, both partial and total skin allografts can be cryopreserved, but the viability is one of the features of CTSCA.
