The term advancement flap usually refers to a flap created by incisions that allow a “sliding” movement of the tissue. Tissue transfer is achieved by moving the flap and its pedicle in a single vector.
Unipedicle advancement flaps
Pivotal flap常常在基底部形成一个猫耳朵，而advancement flap则会两侧个形成一个猫耳朵；前者的猫耳朵须在基底部切除，而后者的猫耳朵可以在沿着皮瓣全长的任意部位切除，所以可以根据需要将其放在更美观的位置。
advancement flap常常矩形的外形，对于圆形或者椭圆形的缺损修复不能适合时，往往需要将缺损“square off”，而不是将皮瓣“round off”。因为直线形瘢痕有助于减少trap-door deformity的发生。
皮瓣长度与缺损宽度比例常常为3：1，所以大的缺损常采用两个推进皮瓣来进行修复（Bilateral unipedicle advancement flap）。
Bilateral unipedicle advancement flap
- A-T repair
- O-T repair
…The resulting standing cutaneous deformity that forms opposite the flap incisions is marked. Only half of the typical incision to excise the deformity is made. This creates a flap of skin that is pivoted and advanced into a second horizontally oriented incision made in the opposing lip segment. The orientation and length of the second incision are designed after the first incision creating the flap of skin has been performed. The flap is positioned over the adjacent lip segment, and the distal end of the overlapping flap is marked on the lip segment. A line is drawn from this point to the lip segment wound border. The line is angled so it is centered beneath the linear axis of the overlapping flap. An incision is then made along this line. The borders of the incision are undermined. The flap is then sutured into the recipient site created by the second incision. On occasion, a small portion of the flap must be trimmed to allow it to fit perfectly within the opposing lip segment…
V-Y and Y-V advancement flap
Subcutaneous tissue pedicle island advancement flap
Bipedicled advancement flap
Defects in or near the midline (within 3 cm) are best closed without making horizontal incisions. Rather, they are treated like a primary wound closure, with advancement by dissection in the subgaleal plane, because all sensory nerves are superficial to this plane of dissection. If the entire defect cannot be closed by primary apposition of wound margins, the remaining portion of the wound is left open to heal by granulation.
The perimeter of the skin island is incised to the levelof the subcutaneous tissue. Undermining of the adjacentfacial skin peripheral to the flap for a distance of 2 cm is performed at this level. Blunt and sharp dissection is then carried through the subcutaneous tissue surrounding the skin island, beveling slightly away from the skin island down to the level of the fascia overlying the facial musculature. This frees the elastic subcutaneous tissue pedicle from its medial and lateral fatty attachments to surrounding cheek fat while preserving its vascular supply, which is derived from its deep attachments. The skin island is then advanced toward the defect by placing a skin hook at its leading border (Fig. 9-12). At this point, the pedicle can be narrowed to facilitate the advancement of the flap. This is accomplished by back cutting the peripheral borders of the flap in a subcutaneous plane, leaving at least one-third of the total flap surface area attached to the underlying subcutaneous tissue. Further thinning of the subcutaneous tissue underlying the undermined portion of the flap may be performed to create an appropriate thickness match between the leading border of the flap and the recipient site. A central pedicle of one-third of the total skin island surface area will adequately perfuse the skin island. Further subcutaneous undermining of the skin adjacent to the flap is required if puckering of the peripheral facial skin occurs with flap mobilization. Subcutaneous undermining is also performed at the recipient site. In addition, the recipient site’s depth and shape may be modified by removing skin and subcutaneous tissue so that scars will be along aesthetic boundary lines and the defect will more appropriately accommodate the thickness of the advancement flap. The leading border of the skin island is fixed in place, and the wound surrounding the remaining perimeter is subsequently closed such that wound closure tension is equally distributed over the entire length of the flap.
皮下蒂相对于经典设计的推进瓣而言，没有猫耳朵形成，所以不会有皮肤的浪费，但是发生”trap-door deformity”的机率会增加，尤其是修复小的缺损时（smaller than 2cm）。
1/2以下的缺损可转换为圈层缺损直接关闭。更大的缺损可以使用Bilateral unipedicle advancement flap关闭。V-Y皮下蒂皮瓣更适用于上唇缺损修复，口裂外侧部位皮下脂肪丰富，可作为皮下蒂皮瓣的蒂部（the flap is freed from its orbicularis muscle attachments near the commissure and is based solely on the abundant subcutaneous fat located just lateral to the commissure）。
If the width of the flap does not extend to the cheek fat lateral to the orbicularis oris, the muscle is left attached to the majority of the underside of the flap. Only peripheral margins of the flap are undermined to allow eversion of the wound edges. It may be necessary to incise through some of the muscle to increase mobility. When the flap is sufficiently wide to incorporate the abundant fat lateral to the orbicularis oris, the flap may be partially or completely released from the orbicularis oris for greater mobility.