Principles, Design, Completion



Principles, Design, Completion





1.1 PRINCIPLES OF RECONSTRUCTION

The first step in cancer surgery is to ensure clearance of the tumor. Neither cosmetic nor functional goals can be met if the results are short-term, and the patient will require further surgery to remove persistent tumor. Taking too narrow a surgical margin or leaving positive surgical margins untreated will likely doom the patient to more extensive cancer surgery and reconstruction in the future. Although adjuvant radiation therapy may help “clean up” some residual tumor cells in some situations, a better, more consistent option may be to consider Mohs micrographic surgery as a primary method to clear difficult or recurrent skin cancers before reconstructive surgery.

Mohs surgery was first described in the 1930s by Dr. Frederic Mohs. At that time, the procedure was described as “chemosurgery” in reference to the zinc chloride paste that was applied to the tumor prior to surgery. This process fixed the tissue “in situ,” and although it made surgical excision of the tumor easier in some ways, it made immediate postoperative reconstruction of this devitalized wound bed impossible. Although Dr. Mohs did perform the procedure without zinc chloride paste in certain locations such as the eyelids, several other physicians began utilizing Mohs surgery without zinc chloride paste in the 1970s, a procedure subsequently referred to as “fresh tissue technique.” Today, almost every case of Mohs surgery is performed without the tissue fixative, and the procedure is termed Mohs micrographic surgery. The two greatest benefits of the procedure are that it provides the highest cure rate for most primary and recurrent skin cancers and preserves the greatest amount of healthy tissue around the tumor site. Even if another surgeon will be performing the reconstruction, it may be in the patient’s best interest to have the tumor removed by Mohs surgery. And for the surgeon performing the reconstruction, the benefits of highest cure rate (i.e., less chance of performing another excision and repair in this area) and greatest preservation of healthy tissue (i.e., more healthy adjacent tissue means more options for local flap or side-to-side repair) should sound like a good option.

After cancer removal, we address the two goals in reconstruction: functional and aesthetic. Both of these should be addressed in consultation with the patient, and one should get a sense of whether one’s ability and goals will match the patient’s expectations. (See also Section 1.3.) As mentioned before, selection and performance of reconstructive technique needs to address functional as well as aesthetic requirements. Functional requirements may include the eyelids’ protection of the globe, the lips’ retention of food and liquids, the ears’ collection of sound, and the nostrils’ movement of symmetric and uninterrupted air flow. Each of these functional requirements can be disturbed by a poorly planned or executed reconstruction. A suboptimal
aesthetic result can more easily be addressed in a subsequent or revision surgery; however, the preference is to reach both goals first time around.

In considering any defect for reconstruction, three questions should be considered:



  • 1. What is missing?


  • 2. Where am I going to find the replacement tissue?


  • 3. How am I going to get it there and hide most of the subsequent scars?

Let us examine each of these.

“What is missing?” Each defect is different. Does the defect involve only skin and soft tissue, or is structural integrity also missing? If only skin and soft tissue, is it superficial or deep? Is it in an area where second intention healing may provide excellent results? Many defects in concave areas heal quite well through proper wound care and the body’s own innate mechanism of wound repair. As a result, many defects of the conchal bowl may best be treated by good wound care and second intention healing (Section 7.4). Defects on the temple too large to easily repair with a side-to-side or flap repair can also be allowed to heal by second intention healing (Section 4.8). Superficial defects on the medial canthus (especially if balanced above and below the medial canthal tendon and not adjacent to the lid margin) and superficial defects on concave areas of the nose (e.g., alar crease) can also be allowed to heal by second intention healing with exceptional results.

Now, if the defect is deeper or impacts structural support or is on a convex surface or crosses into another cosmetic unit or subunit, one should consider other options. Deeper defects, especially if near a free margin (e.g., eyelid or vermilion border) or anatomical landmark (e.g., eyebrow or nasal tip), should be repaired to minimize scar contraction and thereby minimize the risk of deviation of the free margin or landmark. So although large defects on the temple can be allowed to heal by second intention healing with exceptional results, if that defect approaches the lateral canthus or the tail of the eyebrow, a repair should be considered to minimize the risk of distortion of the lateral canthus or eyebrow. In these instances, it might be worth the extra time and work to place a full-thickness or split-thickness skin graft on the temple defect because the graft will decrease the chance of wound contraction and subsequent distortion (Section 8.6F-H).

If the defect involves structure or if contraction of the wound might compromise function, one should consider structural support via cartilaginous grafting. Most surgeons agree that if structural support is missing (e.g., nasal tip) or if there is a possibility of impairment of function (e.g., over the internal or external nasal valves), then one should replace or restore the structural integrity of the anatomy. Similarly, when nasal mucosa is missing, it should be replaced because although small full-thickness nasal defects may heal without complication, larger defects repaired without mucosal replacement may heal with significant contraction and distortion. In fact, the earliest midline forehead flaps (see image of moulage of forehead flap in front matter of book) were often fraught with this complication, and it was not until various
methods to address the missing nasal mucosa and structural support were developed that the aesthetic utility of this flap for complicated nasal repair was truly recognized.

So, if superficial, consider second intention healing, especially on a concave surface away from free margins and anatomical landmarks. If deeper, consider reconstruction of some method. If there is a specific cosmetic or functional quality to the missing tissue, such as the hair-bearing eyebrows or lining of the nasal vestibule, replace with tissue of similar characteristic (Section 4.2). And if structure is missing or structural support is needed to decrease the chance of functional or aesthetic distortion, reconstruct the structure or add adequate support to avoid distortion.

The second question is “Where are you going to find the replacement tissue?” The tissue with the greatest similarity to the missing skin of the defect (i.e., color, texture, thickness, adnexal structures, actinic damage) is tissue from the same cosmetic subunit adjacent to the defect. Unfortunately, tissue within the same cosmetic subunit is frequently inadequate for reconstruction, but the tissue with the second greatest similarity to the tissue being replaced is probably within an adjacent cosmetic subunit. This similarity allows local flaps to be an excellent reconstructive option in repair of defects on cosmetically sensitive areas. Tissue of similar color, texture, and thickness is being used to repair the defect. As a result, local flaps tend to be a superior reconstructive option compared with grafts for repair of these areas. This is especially true over convex areas (e.g., nasal tip) or deeper defects, where grafts cannot reconstruct the depth of the wound but only its surface. In cases where the defect is too large for repair with a local flap, you might have to go to another cosmetic unit to find the replacement tissue. For large or deep or complicated defects on the nasal tip, this might be the forehead, where a paramedian forehead flap might be the best alternative (e.g., Section 5.12). For a similar complex defect on the nasal ala or soft triangle of the nasal tip, one might consider a cheek-to-nose interpolation flap from the medial cheek (Section 5.11). Both the forehead and the cheek have similar characteristics to the skin of the distal one-third of the nose and are excellent sites for replacement tissue. If the defect is superficial but too big for local flap repair, another alternative is a full-thickness skin graft. Although the usual donor site may be the pre- or postauricular skin or the supraclavicular area (Section 4.4), an alternative is to use adjacent tissue for the skin graft, a procedure that has been referred to as an adjacent-tissue skin graft or a Burows’ graft. In this instance, tissue adjacent to the surgical defect is used as a donor site for the full-thickness skin graft. This may be particularly useful in defects that extend beyond one cosmetic unit or subunit into another. In these cases, one closes the defect in individual cosmetic units or subunits and in doing so, creates redundant tissue that is used to repair the remaining surgical defect (Section 8.6).

Finally, we have to ask, “How are you going to move the needed tissue from where it is located to where you need it?” The trick here is to accomplish this feat without distortion of anatomical landmarks or free margins and hide incision lines (and thus subsequent scars) as well as possible. To avoid the former, proper design of the side-to-side or flap repair is essential to avoid secondary tension vectors (i.e., tension caused by execution of the repair), which could distort nearby free margins or landmarks. For the latter, consider placement of incision lines within
rhytides, furrows, or the junctions between cosmetic units or subunits. It is likely that these two factors discourage less experienced reconstructive surgeons from considering local flap repairs. It is much easier to place a full-thickness skin graft on a surgical defect than to worry about secondary tension vectors or hiding incision lines even if a local flap will provide a more similar skin surface and reconstruct depth as well.

So, if each defect is approached in the same logical, step-by-step manner, the reconstructive process becomes easier and adaptable to different situations. Rather than trying to remember a specific repair for a specific site, it is more useful and versatile to consider the following questions: what is missing, where are you going to find its replacement, and how are you going to get it there?

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Oct 13, 2018 | Posted by in Reconstructive surgery | Comments Off on Principles, Design, Completion
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