Editing Skin flap design and principles (section)

== Flaps in continuity ==

* Defined as blood supply for the flap coming through an intact skin bridge
* Transposition flaps
** Donor site runs radial to the defect
** Donor site is closed directly, and the flap crosses over intervening normal skin to enter the defect
** The point at the base of the flap opposite the defect is called the pivot point and this does not move
* Rotation flaps
** Do not cross intervening tissue, but advance directly into the defect
** Roughly semicircular with the pivot point at the far end of the incision from the defect
** Takes up tension over the whole incision
** Can use a back-cut at the far end to allow further advancement of the tip of the flap. Usually you can set up the flap so that the back cut is made in an area with loose skin.
* Advancement flaps
** Either one limb or two limb
** Two limb advancement flaps are susceptible to pin-cushioning
** Takes up skin in the direction of closure, parallel to the incision
** Advancement flaps in continuity are most useful for reducing dog ears, whereas island advancement flaps will help close wounds that would not otherwise close
* Rhomboid flaps
** Subtype of transposition flaps
* Bilobed flap
** Transposes skin through an angle up to 180 degrees while avoiding dog ears


=== Pivot points ===

* Pivot point - the fixed point at one side of the base of the flap in rotation and transposition flaps. If there is tightness in the closure, there will usually be a tension line beginning at the pivot point and extending to the far side of the defect. If this tightness is seen, the flap is high-risk for ischaemia, particularly venous ischaemia. Avoid this by ensuring the distance from the pivot point to tip of flap is the same as the distance from the pivot point to the far side of the defect.