Advancement flaps

Introduction

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

有时被叫做U-plasty。

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。

与旋转皮瓣一样存在皮瓣边长小于切口总长度的情况。

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

根据缝合后的形状又被称为H-plasty或T-plasty。

T-pasty

与H-plasty相比，T-plasty只需要一个切口便能做出两个瓣，所以瘢痕相对更少。

• A-T repair

• O-T repair
  

Modified T-plasty

T-plasty由于垂直瘢痕的收缩以及存在旋转动作导致皮瓣长度缩短的原因，常常引起组织移位，改良的T-plasty就是为了解决这个问题而在垂直部分增加了类似Z-plasty的部分。

…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

早期用于头皮缺损修复，但由于其secondary defect常常需要植皮，所以面部应用较少。

Applications

Forehead

对于前额中间1/3部位的缺损，采用垂直方向皮瓣切口设计，以获得最佳的美容效果，这一部位的皮瓣制备时分离部位位于帽状腱膜下；

而对于paramedian以及lateral的缺损，则需要采用水平方向的切口设计才能获得最佳的美容效果，分离平面位于subcutaneous，以保护其深面的眶上及滑车上神经。

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.

由于前额皮肤弹性较差，故对于较大的缺损常需设计成bilateral形式的推进瓣。

Cheek

对于中等到较大（2-4cm）的缺损，可以采用颊部皮瓣修复：

对于较小的缺损（2cm，or less）可以通过外形修整后直接缝合。无论是直接缝合还是皮瓣修复还是修整较后直接缝合，都需要注意将切口隐蔽在天然的皱褶、沟纹以及美容区分界线处。

对于颊部内侧的缺损而言，修复时需要注意保护鼻面沟的外形，所以在颊部内侧和鼻侧面都存在缺损时，往往需要各自采用独立的方法进行修复，使用一整个颊部皮瓣进行修复的时候常常会使鼻面沟消失。对于缺损位于鼻面沟但是没有涉及鼻侧面时，可以通过将皮瓣在鼻面沟位置的骨膜上固定一针来进行改善。

V-Y皮下蒂皮瓣适合鼻翼水平及以下的颊部缺损的修复，可以利用该区的唇面沟等天然结构隐蔽瘢痕。

皮下蒂皮瓣的制备：

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）。

外侧颊部相对于内侧颊部而言，皮下脂肪组织很少，皮肤与筋膜附着更紧密，所以皮下蒂难以运用，对于较大的缺损需采用旋转推进瓣获取下颌角去以至颈上部的皮肤进行修复。

Eyelid

Lip

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.

Case reports

Not shown