Abstract
A rotation flap employs an arciform incision adjacent to an operative wound in order to recruit laxity from multiple directions and redirect flap closure tension. Adjacent tissue laxity assists flap rotation into the primary defect, and the tension vector is redirected in part to the secondary defect/motion of the flap. Rotation flaps recruit laxity by lysing deep restraint and by widely severing and redirecting dermal restraint. Rotation flaps may also displace dog-ears to more favorable locations.
Well-designed rotation flaps create scar lines that are hidden along facial boundaries or within relaxed skin tension lines. There are few repairs as elegant and seemingly simple as a well-designed and well-executed rotation flap. In practice, flaps that utilize only rotational motion are uncommon. Most rotation flaps combine several different types of motion, and most incorporate a significant degree of tissue advancement. Rotation flaps have long been utilized in plastic and general surgery for the reconstruction of larger truncal wounds including pilonidal excisions. In the last three decades, rotation flaps have found a greater use for the reconstruction of facial wounds.
Keywords
rotation, flap, undermining, design, pivotal restraint
A rotation flap employs an arciform incision adjacent to an operative wound in order to recruit laxity from multiple directions and redirect flap closure tension. Adjacent tissue laxity assists flap rotation into the primary defect, and the tension vector is redirected in part to the secondary defect/motion of the flap. Rotation flaps recruit laxity by lysing deep restraint and by widely severing and redirecting dermal restraint. Rotation flaps may also displace dog-ears to more favorable locations.
Well-designed rotation flaps create scar lines that are hidden along facial boundaries or within relaxed skin tension lines. There are few repairs as elegant and seemingly simple as a well-designed and well-executed rotation flap. In practice, flaps that utilize only rotational motion are uncommon. Most rotation flaps combine several different types of motion, and most incorporate a significant degree of tissue advancement. Rotation flaps have long been utilized in plastic and general surgery for the reconstruction of larger truncal wounds including pilonidal excisions. In the last three decades, rotation flaps have found a greater use for the reconstruction of facial wounds.
Rotation Flap Design: Basic Principles
The classic rotation flap incorporates a triangulated defect and a smooth curvilinear arc. The long arciform dermal incision achieves substantial reduction in tension in the primary motion of the repair. Rotation flaps are sometimes hindered in their movements by the inherent stiffness of the tissue at the point of pivotal restraint along the lagging edge of the rotation arc. Such restraint may cause the tip of a properly designed flap to fall short of its destination at the apex of the primary operative wound ( Fig. 5.1 ). In many cases, the tip is simply advanced under some tension to close the wound, but this may impair distal flap viability. To overcome this issue, the arc of the flap may be extended and the leading edge of the flap lengthened. When the elongated rotation is executed, the extended tip of the flap drapes without tension where it meets the distant point of the primary defect ( Fig. 5.2 ). This concept has been demonstrated in vivo in a porcine model.
A rotation flap can frequently be closed without undermining beneath the point of pivotal restraint; however, for optimal flap motion, this area of restraint should be undermined ( Fig. 5.3 ). This is particularly important with the dorsal nasal flap, where maximal rotation is required to close a defect located in the inelastic skin of the distal nose. Proper undermining of the pivot point accomplishes the release of deep restraint and usually allows substantial motion of the flap. This undermining is not without some risk, as too much undermining may interfere with deep vascular perforators. However, the reduction in tension on the flap tip usually more than compensates for any diminishment in pedicle vascularity.
A back cut into the rotation flap’s body can improve flap mobility, particularly on relatively immobile skin such as on the scalp. A back cut frees both deep and lateral restraint and can prove valuable in reducing closure tension, but a back cut also has the potential to compromise the vascular supply of the flap’s pedicle. The more ample the residual vascular input, the more extensive of a back cut may be created. If, as in the case of the dorsal nasal flap, the remaining pedicle contains large-caliber axial vessels, the width of the pedicle may be safely narrowed and a substantial back cut will be tolerated. The defect from a back cut is usually closed with a V-to-Y repair, trimming excess tissue from the apex of the flap as indicated. Alternately, the apex may be closed with a Z-plasty.
Flap Length
Rotation flaps create long incision lines. A longer arc of flap rotation facilitates closure of the narrowed secondary defect and minimizes wound closure tensions, both in the primary and secondary motions of the repair. In addition, a longer rotation flap allows for easier redistribution of tissue redundancy along the longer outer arc of rotation. Thus the incision lines for rotation flaps typically need to be longer than one would initially expect if the flap is to be placed under minimal tension and if the unwanted displacement of structures surrounding the primary defect is to be avoided. A common error in scalp reconstruction is to undersize a rotation flap with the resultant inability to close the operative wound.
Flap Curvature
Most rotation flaps are designed with an arc that transects about one-quarter of a circle. Such a flap design reliably redistributes tension vectors along the secondary operative defect. Rotation is limited by the surface restraint of the pivot point. The greater the curvature of a flap, the greater degree of rotation can be accomplished. Similar to a back cut, a greater curvature actually cuts into the pedicle and permits greater freedom of movement by freeing pivotal restraint. However, too great of an arc of rotation will actually redirect tension “backward” and may negate the decrease in tension that the rotation flap was supposed to accomplish ( Fig. 5.4 ).
Because rotation flaps require long incision lines to achieve appropriate flap motion, in many facial locations other flap options may be preferable. Rotation flaps have their greatest utility in the closure of scalp, temple, and cheek defects. In select cases, rotation flaps are also quite valuable on the nose. On the scalp, a lack of adjacent skin mobility requires rotation flaps to be especially long in order to close even small to moderate-sized operative wounds. On the cheek, rotation flaps are particularly useful for the repair of medially located wounds, because the rotation flap can effectively mobilize the large reservoir of loose skin in the entire area of the lateral cheek. Infraorbital wounds can be closed with rotation flaps that recruit substantial laxity from the temple. Because rotation flaps tend to be rather “short” flaps when the distance from the flap base to the tip is considered, their vascular supply is quite predictable, and ischemic failures of the flaps are very uncommon if the flaps are closed under low tension.
Bilateral Rotation Flaps
Bilateral or dual rotation flaps utilize rotation from two sides of an operative defect to allow for wound closure where motion from one side would either be inadequate to close the wound or where symmetry of the repair is desired for enhanced cosmesis. Bilateral rotation flaps are most useful for large forehead wounds where a bicoronal incision is utilized ( Fig. 5.5 ), for chin defects where the arc of the bilateral rotation lies within the mental crease, and lip defects where it is preferable to spread the tension out evenly over the entire lip.
O–Z Rotation Flap
The construction of an O–Z flap involves the creation of opposing rotation flaps, one of which takes origin from one side of the operative wound and the other as a mirror image from the opposing side of the defect. In the design of the O–Z flap, however, there is great flexibility. The paired flaps can be designed to rely upon pure rotational movement, or there can be varying amounts of flap advancement introduced into the operative design. As with traditional rotation flaps, the movement of O–Z flaps produces paired standing cone redundancies near the flaps’ pivot points, and these redundancies are either excised or sewn out by the rule of halves. The O–Z repair has its greatest application on the scalp, where the flap’s prominent incision lines are typically hidden beneath a blanket of hair ( Fig. 5.6 ).
Selected Rotation Flaps
Dorsal Nasal Rotation Flap
Surgical defects of the distal third of the nose present unique reconstructive challenges. The skin of this area is stiff, sebaceous, and inflexible. Although some broad distal nasal wounds may be appropriately repaired with skin grafts, grafts often result in texture and color disparities, and grafts will not reliably survive over exposed cartilage. Many local nasal flaps do not allow adequate tissue movement for larger defects and can produce alar asymmetry and tip elevation. Distant pedicled flaps provide superior outcomes but require multiple surgical procedures.
In 1967 Rieger introduced the dorsal nasal rotation flap for the reconstruction of distal nasal wounds ( Fig. 5.7 ). The Rieger flap is a random pattern rotation flap that pivots on a muscular pedicle from the medial canthus and nasofacial sulcus. The flap described by Rieger is a full-thickness rotation of the entire nasal dorsum with a glabellar back cut to improve flap mobility. The flap is designed with a long sweeping arc that extends from the superior aspect of the defect to the nasofacial sulcus, past the contralateral medial canthus to a midpoint just superior to the glabella. In order to include the abundantly perfused underlying nasal musculature, the flap is elevated at the level of the underlying perichondrium or periosteum. Although not originally described by Rieger, it is often beneficial to change undermining planes at the glabella and elevate the flap above the procerus and medial inferior corrugators in this area. This avoids the transfer of thick glabellar skin to the thin skin of the contralateral medial canthus. The point of pivotal restraint with the dorsal nasal flap is located in the areas of the ipsilateral medial canthal tendon and the attachment of the nasal musculature to the nasofacial sulcus. As with all rotation flaps, undermining in the area of pivotal restraint can improve flap mobility, but this undermining should be performed under direct visualization in order to protect the flap’s vascular pedicle. Properly executed, the dorsal nasal flap can be used to repair distal nasal defects up to 2 cm in diameter and is most useful for medium-sized distal nasal defects too large to be repaired with bilobed transposition flaps and too small to warrant the use of two-staged pedicled flaps ( Fig. 5.8A ).
