Reconstruction with VRAM Flap and STSG
Kenneth D. Hatch
GENERAL PRINCIPLES
Vaginal Split-Thickness Skin Graft (STSG)
Skin grafting is useful in gynecologic oncology to cover a defect left after surgical excision of the vulva or vagina. It is also commonly used for a neovagina in young women who have vaginal agenesis. Normal skin is composed of (1) the stratified squamous epithelium that provides protection against microbes and prevents loss of water from the body and (2) the dermis which consists of collagen and elastin that give the skin mechanical strength. The skin appendages, such as the hair follicle and its companion sebaceous gland, extend through the dermis to the subcutaneous fat. The sweat glands’ origin is in the subcutaneous fat.
Definition
A skin graft is a segment of skin that is completely separated from its blood supply and transplanted to a recipient site where the skin is missing. A full-thickness skin graft consists of the entire epidermis and dermis down to the subcutaneous fat. It is rarely used in gynecology. The STSG consists of the epidermis and varying degrees of the underlying dermis. It is categorized as thin, intermediate, or thick as shown in Figures 8.1 and 8.2. The thin graft has the most capillary network at the epidermal/dermal junction and will have the best survival. It also will have the most secondary retraction since it has less of a collagen base. The intermediate graft is the most used in gynecology. It is cut with the setting of 0.014- to 0.016-in thickness. It has slightly larger vessels from deeper in the dermis and has more collagen; so the maturation of the skin graft is faster and shrinkage is less. The thick graft will have less contraction but a lower survival rate.
Nonoperative Management
Abdominal wounds that are opened because of infection are best treated with dressing changes or wound VAC and allowed to heal secondarily. The skin graft is most often used to cover defects on the vulva to stop the granulation process that produces scarring and bring a more normal appearance.
Vertical Rectus Abdominis Myocutaneous (VRAM) Flap for Vaginal Reconstruction
The VRAM flap is often used to create a neovagina following an exenteration.
It has several advantages over the STSG. It brings a new blood supply to the irradiated tissue in the pelvis, it fills space in the pelvic defect and keeps the small bowel from adhering to the pelvic floor, and it has a better survival of the skin surface and less chance of stricture.
Compared to the gracilis flap it has better survival, is easier to place in the pelvis when a low rectal anastomosis is performed, and avoids the large medial thigh scars following a gracilis flap.
The gracilis flap is best used when a total exenteration with a large perineal phase is performed. It fills the perineal and pelvic defects and decreases the risk of herniation of small bowel through the perineum. The gracilis flap is demonstrated in Chapter 5.
Anatomic Considerations
A general discussion of flaps is in Chapter 5.
The VRAM flap used for pelvic reconstruction relies on the deep inferior epigastric vessels. If the patient has had a transverse lower abdominal incision, the integrity of the vessel should be established by Doppler.
The flap is centered around the umbilicus because of the many perforators penetrating the skin in this area.
The flap will be taken on the side that the vertical incision went around the umbilicus.
The muscle will be paralyzed and the skin will lack sensitivity because the motor and sensory nerves are disrupted.
PREOPERATIVE PLANNING
STSG
Selection of the donor site should be done prior to the operation. The best location is the lateral thigh or the lateral buttock over the trochanter of the femur. Here the skin is thick enough to heal rather quickly and the nerve endings are not as prominent as in the medial thigh. To hide the donor site scar the patient should be marked where her underpants or swimsuit will cover it. The patient is asked which side she sleeps on so the graft can be taken from the opposite side. If she does not know, ask on which side of the bed she gets up. If it is the right side, the graft should be taken from the left.
Evaluation of the recipient site suitability for the graft should be done carefully. Infection, devitalized tissue, seroma, hematoma, and uneven surfaces may interfere with the survival of the graft. Fat is not a good surface because it does not have an abundance of blood vessels that will provide a new blood supply. For vulva grafting the fat should be allowed to form healthy granulation tissue with a salmon color.
SURGICAL MANAGEMENT
STSG
When a neovagina is being performed for vaginal agenesis the graft can be taken before the patient is positioned for the creation of the recipient site.
 Figure 8.1. Anatomy of the skin. |
 Figure 8.2. Levels of split-thickness skin graft. |
Positioning
For a lateral thigh or buttock donor site, the patient is placed in the lateral Sims position exposing the chosen side for harvesting the graft.
The supine position could be used for anterior thigh donor site.
Approach
Choosing the dermatome: Most surgeons prefer the air- or electric-powered dermatome. The Zimmer and the Padgett are two examples.
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