Rhombic flaps

Introduction

着手选择及设计供区皮瓣前需要综合考虑以下因素：

皮瓣转移和修复对周围解剖结构和标志的影响，避免导致重要解剖标志——如眼睑、嘴唇、鼻唇嵴等——的移位和变形；(First, mobile structures such as the eyelid, lip, and melolabial fold must be accounted for in planning the flap and care taken to avoid distortion of these structures due to unfavorable vectors of tension.)
供区的皮肤需要有足够的松弛度，以完成皮瓣的转移；(Second, an area of skin must be identified with adequate tissue laxity that is best suited for construction of a flap.)
须对供区及受区的RSTLs、LME以及美容边界标志进行仔细评估，以获得最好的瘢痕隐蔽以及最小的缝合张力；(Third, a careful evaluation of relaxed skin tension lines (RSTLs), lines of maximal extensibility (LME), and aesthetic boundaries must be made to plan incisions that will maximize scar camouflage and minimize wound closure tension.)
对术后的瘢痕及张力应有预见性，这是皮瓣选择及皮瓣方位设计的决定因素。(Fourth, scars and all vectors of tension after transfer of a flap must be anticipated, and these are the determining factors for flap selection and orientation.)

Limberg flap

limberg flap即最初的经典菱形皮瓣，其缺损由内角为60°和120°的菱形构成，因此缺损的四条边以及短的对角线长度相等，当缺损形态不符合时，需要牺牲正常的皮肤组织以将缺损区修整成60°和120°的菱形，这一点也是limberg皮瓣的缺点之一。

皮瓣的设计为由短的对角线作出与边长等长的延长线切开皮肤，再以此长度成60°夹角形成皮瓣的另一个切口，皮瓣的大小和缺损区等大。按照上述设计缺损的一边可形成两个菱形，而对角线可向两边延长，故可形成四个供选择的皮瓣。皮瓣转移后，最大张力位于供区，其方向大致平行于缺损与皮瓣邻边的方向，这一方向能否与LME平行是四选一时决定菱形皮瓣位置的最重要因素。

limberg皮瓣常用于颊部、颞部、眼睑、鼻、唇、颏部以及颈部等区域缺损的修复。前额由于存在水平的皱褶，非常不适合菱形皮瓣的修复。

limberg皮瓣的缺点一是修整缺损区及皮瓣转移形成的猫耳朵时需要舍弃正常皮肤，二是难以隐蔽产生的所有瘢痕。

Dufourmentel flap

Dufourmentel flap是limberg flap的一个变种，与limberg flap相比，它几乎适合任何菱形缺损的修复，而不需要将菱形内角限制在60°和120°，所以减少了修整缺损时的组织浪费；但是和limberg一样，Dufourmentel flap只能被用于修复菱形缺损（缺损四边的长度相等）。

其设计方法如下：延长短对角线及其一条邻边得到一个夹角，作此夹角的角平分线段，其长度等于菱形边长，此为皮瓣的第二条边；由此线段的端点作一平行于长对角线的线段，线段长度等于菱形边长，此为皮瓣的第三条边。

由设计方法可以看出，Dufourmentel flap比limberg flap的旋转角度更小，所以形成的猫耳朵也会更小；Dufourmentel flap同样存在四个位置的选择，其原则也是需要考虑张力方向与LME平行的原则；同limberg flap一样，难以做到将所有的瘢痕都隐蔽在RSTL内。

Webster 30° flap

又叫做30°菱形皮瓣。这一变种的目的在于降低供区缝合时的张力，减小皮瓣转移过程中形成的猫耳朵畸形。

其设计方法如下：

First, the excision of the standing cutaneous deformity is performed as a W-plasty to limit the length of the excision of the deformity. Second, the apex of the flap is designed with an angle of 30°. The Webster 30° flap is designed by approximately halving an equilateral triangle. The height of the triangle is designed with a height equal to the length of a side of the defect. The angle of the apex of the transposition flap is 30°. The width of the base of the flap is half the greatest width of the defect. The Webster 30° transposition flap allows a more even distribution of wound closure tension but is more likely to distort neighboring structures.8 This is because the surface area of the flap is less than the surface area of the defect that the flap is designed to repair. Thus secondary tissue movement is necessary to assist the flap with closure of the primary defect. Furthermore, care must be taken to ensure that the angle created between the flap and the adjacent side of the defect is at least 110°.5 A lesser angle may result in vascular compromise of the repair. The Webster modification results in an irregular closure line because of the W-plasty but does so at the expense of an additional limb of scar.

Variations of flap design

经典的菱形皮瓣要求将缺损区修整成内角为60°和120°的菱形，即使经过Dufourmentel flap以及Webster 30° flap的modify后也只能用于方形缺损区的修复。菱形皮瓣的另外一种设计是将方形的皮瓣用于修复圆形的缺损区，这样就完全避免了修整缺损区时的组织浪费。

其设计方法如下：

The flap is designed by selecting a diameter of the defect based on the area of greatest tissue laxity and the desired location for placement of flap donor site scars. To create the first side of the flap, the line of the diameter is extended beyond the defect for a distance approximately two-thirds of the length of the diameter. The second limb of the flap, of equal length to the first, is drawn from the end of the first line, creating a 60° angle. The line follows the curve of the adjacent border of the defect (Fig. 11-7). Care is taken to avoid narrowing the flap’s base as the line parallels the curved border of the defect. After dissection of the flap and appropriate undermining of adjacent skin, the flap is transferred to the defect and key sutures are placed to distribute wound closure tension. The scar resulting from flap transfer tends to look remarkably like that occurring after use of a Limberg flap.

这种设计方法具有三个优势：

由于是将一条直径延长出去形成菱形的一条边后才决定了皮瓣的位置，所以可以根据需要将皮瓣放置在缺损区周围任何合适的位置；
由于以上有点而可能具有更好的瘢痕隐蔽效果；
由于不需要将缺损区修整成方形，所以避免了组织的浪费，仅仅在去除皮瓣转移时形成的猫耳朵时需要切除一部分正常组织。

其缺点是由于形成的皮瓣面积比缺损区面积小，所以在转移后缝合缺损区的时候会相比常规设计的菱形皮瓣，张力会更大，可能会导致缺损区周围的组织移位，这一点必须在皮瓣设计的时候考虑到。另外就是猫耳朵的形成，有报道175个患者中其猫耳朵畸形产生的机率高达22%。但是由于皮瓣面积较笑，所以供区创口关闭时的张力相对经典设计来说会更小一些。

所以这一设计是以增加缺损区创口关闭张力为代价，增加了皮瓣设计的灵活性。