Skin expansion as an alternative for head and neck reconstruction.
Where to place expanders in the head and neck.
How to place expanders in the head and neck.
Management of expanders in the head and neck.
Complications associated with expanders in the head and neck.
Surgeons repair most skin defects in the head and neck with simple tissue mechanics. These techniques harvest the inherent elasticity of skin, mechanical skin creep, local or distant flaps, or grafts. In the arena of trauma, routine methods may be dubious or problematic. Reasons may include the following:
Host issues: other compromising trauma issues
Existing local scars or lacerations
Lack of available adjacent tissue
Local flap scars may be unaesthetic
Inexperience with large defects
Contaminated or avascular tissue bed
In these instances, a plan for local skin expansion may create new local skin with the advantages of matching color and characteristics. Acutely, complex tissue planning is abrogated because the only acute need is to prepare the wound for grafting. In this case, expanders may be inserted acutely several centimeters away from the defect (with delayed expansion), or, at least 6 weeks after grafting, to allow tissue to be adherent to prevent extrusion of the expander.
The authors have used expansion for both pathologic and traumatic defects. Their commonest use has been for scalp defects. Regardless of defect, planning for expanders is identical, after acute compromising issues are eliminated ( Fig. 1 ).
Choice of expander
Expanders have been shaped to provide tissue coverage for specific elective choices. Hence, round expanders are ideal for breast reconstruction, and croissant-shaped expanders are often the unique choice to move scalp tissue medially in baldness correction. The choice for head/neck expansion is almost always rectangular. This choice fosters preplanning and flap design. Likewise, larger expanders or multiple expanders, when possible, increase efficiency because more tissue becomes available quicker for recruitment.
Location of the expander should be controlled by type of tissue desired in the defect area, plan design of future flaps, and shape of the defect or lesion being removed.
Tissue characteristics of expanded skin should match, if possible, the defect. For example, coverage of a forehead defect means the expansion should include mostly forehead skin, and sometimes hair-bearing scalp.
Plan design of future flaps should be conceived before inserting the expander. For example, anterior scalp defects are usually managed with parietal or occipital expanders. These scalp expansions afford named vascular feeders to the flaps and multiple options for scalp design. Expanded tissue may be used with routine flap methods of advancement, rotation, or occasionally, transposition.
In Fig. 2 , E is the width of expander; D is the distance over the top of expanded skin, and 20% is to allow for stretch back.
Finally, the shape of the defect may modify choice of single or multiple expanders. For example, a triangular defect may be corrected easily by an adjacent expander and a rotational incision method (see Fig. 9 ). A square defect may be corrected with direct advancement or opposing transposition flaps (see Fig. 7 ).
Fig. 3 shows an initial scalp defect and the options for expanders. In the case of a 50-year-old woman after a motor vehicle accident with craniotomy defect covered with acrylic ( Fig. 4 ), the defect is 12 cm. How much to expand? Eight-centimeter base of expander? 8 + 12 + 20% = 24 cm. Or 10-cm base of expander? 10 + 12 + 20% = 25 cm.
→Therefore, the distance over the top of the expanded skin needs to be 24 or 25 cm.
Access incisions to insert the tissue expander are usually designed in 1 of 3 methods:
Through a 2- to 3-cm “V” or “W” at least 3 cm away from the body of the expander.
Multiple linear incisions, perpendicular or radially to the major axis of the expander expansion.
Within the borders of a lesion or graft to be excised.
In the authors’ cases, the first choice was most versatile because dissection was easy and insertion of the expander was facilitated. This method allows filling to begin at 7 to 10 days. Secondary radial incisions (choice no. 2) can be incised for dissection completion.
Occasionally, the surgeon might decide to insert the expander tangential to the expander dissection. This choice occurs when adjacent lesions or grafts and alternate access incisions might be unaesthetic or too remote. Hence, expansion should be delayed for 3 or more weeks to reduce the possibility of extrusion of the prosthesis out of the access site or wound dehiscence.
The tissue expander is usually placed under the skin and subcutaneous tissue, but in the scalp, under galea, muscle, or fascia. The dissection area is controlled by marking the base of the expander on the skin plus 1 cm circumferentially. The dissection is 2 cm or more, larger than the base of the selected prosthesis to avoid tightness of the pocket and to ease insertion. Subgaleal scalp around the curvature of the skull can be dissected with urethral sounds to complete the expander pocket.
Before the expander is inserted, a closed suction drain exits through the most dependent area of the dissection pocket. The drain is removed when fluid is less than 20 to 25 cc over a 24-hour period, usually 2 to 3 days after insertion. Alternatively, some combine exterior port positions with the expander tubing site as a drain at the most dependent location of the dissection.
A prior coronal flap breakdown eliminates the top of the scalp for the expander ( Fig. 5 A). Instead, an 8 × 12-cm expander is placed behind the defect through the open scalp defect superiorly and a V incision (arrow) below ( Fig. 5 B).