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As patient awareness of new hair transplant techniques grows, the repair of improperly planned or poorly executed procedures becomes an increasingly important part of surgical hair restoration. The repairs are performed by excision with re-implantation and/or by camouflage. Follicular Unit Transplants are used for the restorative aspects of the procedure. Using punch or linear excision techniques allows the surgeon to relocate poorly planted grafts to areas that are more appropriate. The key elements of camouflage include creating a deep zone of follicular units, angling grafts in their natural direction, and using forward and side weighting of grafts to increase the appearance of fullness. In special situations, removal of grafts without re-implantation can be accomplished using lasers or electrolysis.

Visible scarring can be a major detriment to a poorly executed hair transplant procedure. Removing unacceptable linear scars by re-excision should be considered when scarring is well localized and the cosmetic benefit from its removal will be more than offset by the decreased density of the surrounding hair. Because of the importance of the surrounding area for camouflage, success in decreasing the size of an existing scar depends as much upon the choice of the scar as upon the actual surgical technique used to repair it.

A number of surgical techniques have the tendency to produce poor donor scars. An understanding of how these techniques may contribute to poor wound healing provides insight into how the repair may best be accomplished. The more common problems are:

* Deep donor incisions
* Wide donor strips
* Suturing with large bites
* Poor wound edge approximation
* Non-contour incisions
* Donor incisions placed too low
* Donor incisions placed too high

Deep Donor Incisions  -

The fascia acts as a structural support for the healing wound. When this support has been violated, the risk of having a widened scar is greatly increased. The use of copious amounts of tumescent anesthesia infiltrated directly into the subcutaneous fat will elevate the dermis and increase the distance from the base of the follicles to the fascia. This is probably the single best way to keep the wound superficial.

With the single-strip harvesting method used in Follicular Unit Transplantation, if the outer edges of the donor strip are cut too superficially, they can be easily deepened with a single blade as the strip is being lifted from the scalp. When using a multi-bladed knife, the standard tool in mini-micrografting, multiple superficially cut strips are almost impossible to deepen in-vivo, and once removed from the scalp further dissection is extremely problematic. Because of this, the surgeon has the tendency to cut more deeply with a multi-bladed knife and this increases the risk of cutting through fascia.

Once the fascia has been cut, the healing will partially obliterate the subcutaneous space. The elimination of this natural surgical plane makes it difficult to judge the depth of subsequent excisions. In the repair, it is therefore important for the surgeon to have greater control over the wound depth. This is best accomplished by using a single-bladed scalpel that allows each wound edge to be treated separately. A single blade is also beneficial when the scarred area is devoid of hair and the angle of the incision does not need to follow the angle of the follicle. In this case, a more perpendicular incision will enable better edge to edge contact and avoid the thin, friable upper edge produced by the fixed angle of some multi-bladed knifes.

When the harvesting is superficial and there is no tension on the wound, a layered closure is rarely needed, as there is no place to position the deeper sutures without impinging on follicles and there is no need to suture the fascia, as it has been left intact. In contrast, with a repair the fascia has often been violated. A meticulous layered closure that includes fascia is important because there is often significant wound tension and the sutured scar tissue regains its wound strength more slowly than normal hair-bearing scalp.

Although one should never undermine in a properly planned harvest in a virgin scalp, in a repair procedure conservative undermining is sometimes required. Undermining should generally be carried out in a superior direction with care to stay deep to the fascia or scar tissue so that follicular damage will be avoided. Undermining in an inferior direction will allow the movement involved in neck flexion to be transmitted to the wound edge, increasing the potential to stretch.

When a layered closure is required, interrupted sutures provide the most secure and controlled approximation of the deeper tissues. Polyglactin 910 (3-0 Coated Vicryl) is a braided absorbable suture that has good tensile strength and handling properties and is an excellent material for deep sutures. Recently, we have been using the synthetic monofilament Poliglecaprone 25 (3-0 Monocryl) for deep closures. This suture has the advantage of causing less inflammation but, being a monofilament, tends to cut through the tissue more easily and is slightly more difficult to tie.

Wide Donor Strips -

In the era of mega-sessions, taking too wide a donor strip has been a common problem in hair transplantation surgeries. A wide strip places unnecessary tension on the donor closure and leads to a widened scar. Hair loss associated with this type of closure does not adequately compensate for advantages of the larger session. When larger sessions are appropriate, and the scalp does not have good mobility, the surgeon should consider a longer incision rather than a wider one. Harvesting a donor strip of appropriate width, so that there is minimal tension on the wound closure, is the single most important thing that a surgeon can do to minimize donor scarring.

Once a wide initial incision had been identified as the cause of a widened scar, it is preferable to wait at least eight months so that the scar has a chance to mature and regain some of its original laxity. On re-excision, it is advisable to make the new strip at least 3-6mm narrower than the previous one. When a tight closure is the cause, one should generally not attempt to remove the entire width of the old scar since this invariably leads to a reoccurrence, or worsening, of the old scar. To facilitate healing, the new excision should extend into one hair-bearing edge. In other situations, when adequate laxity is present, removing the entire scar width may be beneficial. When two hair-bearing areas are approximated, the healing seems to be improved. The issue of whether the additional wound security from suturing into a hair-bearing edge outweighs potential hair loss from the suturing itself should be decided on a case-by-case basis.

In general, the surgeon should not attempt to remove the entire length of the old scar, as a shorter incision will create less tension on the closure. The repair excision may extend further anteriorly than the previous excision, but should not go to the contra lateral side, as the suturing of one side will create tension on the other. If the repair is successful, the remaining scar may be removed in a subsequent session.

A creative way to repair the defects caused by tension closures, called “Deep Plane Fixation” has recently been proposed by Seery. In this technique, he “channels away the tension forces from the superficial, at risk tissues, into deeper tissues where they are harmlessly dissipated.” The procedure is accomplished by first suturing the deep dermis of the superior wound edge to the deep tissues or fascia of the inferior wound edge. The upper dermal/epidermal components of the two wound edges are then sutured together, end-to-end, ideally without tension.

Suturing with Large Bites -

When suturing with large bites a significant amount of hair-bearing scalp is incorporated within the sutures. Especially with a running stitch, any post-op edema or tension in the donor area will tend to compromise the blood supply of the entrapped tissue and may result in permanent hair loss. In addition, if there is any tension on the wound, the mechanical pressure of the sutures can cause hair loss. In the repair procedure, it is useful to use horizontal mattress sutures to reduce wound tension. Small bites, very close to the wound edge, are recommended for the superficial closure. The cutaneous suture, Poliglecaprone 25 (5-0 Monocryl), is excellent due to its low tissue reactivity and relatively slow loss of tensile strength (2-3 weeks). Metal staples are useful when sutures need to be left in place for extended periods of time. However, staples have the disadvantage of not allowing for perfect wound edge apposition and causing greater post-operative discomfort than sutures. The advantage of staples in being less destructive to hair follicles than a running suture is of less importance when the closure involves mostly scarred scalp.

Poor Wound Edge Approximation -

Perfectly opposing the wound edges of the donor incision is a key factor in preventing the scar from stretching. Since the incision made in harvesting the strip should follow the angle of the hair, one edge will necessarily be acute and the other obtuse. Suturing techniques that do not account for the different angles of the two wound edges will not be able to keep the edges flush and will result in inadequate dermal-dermal contact and a spread wound.

Careful suture placement with small bites is the best means of keeping wound edges apposed, but it is often a time-consuming process. Although faster to place, metal staples do not allow for the same amount of control as sutures and can result in a wider scar, especially if there is any tension on the wound. If the wrong suture material or poor suturing technique can be identified as the cause of the wide scar, this can be remedied by a more meticulous closure using the appropriate sutures.

Non-Contour Incisions -

Incisions that do not follow the natural curved contour of the skull tend to heal with wider scars than those that follow it. When a re-excision is planned, it is important to have the new excision follow the natural curvature of the skull, regardless of the linearity of the original excision and regardless of whether the new excision completely encompasses the old excision. Special care should be taken so that the re-excision stays above the mastoid area. It is sometimes useful to make the excisions narrower in this area. In most cases, the focus should be on reducing the size of the original scar and changing its direction, rather than on eliminating it entirely.

Donor Incisions Placed Too Low -

Of the various factors contributing to a widened donor scar, the most problematic with respect to the repair is a low incision on the posterior scalp. Some surgeons feel that hair lower down on the scalp is a good source of fine hair, however, this hair may not be permanent and harvesting it may result in unacceptable scarring due to the location. In the rare instance that 1-hair follicular units are not delicate enough, (such as in the front edge of the temples, or the leading edge of a female hairline) fine hair may be generated by removing all, or part, of the bulb of terminal hair harvested from the mid-permanent zone.

As discussed in the section “Limitations,” the most desirable position for the donor scar is in the mid-portion of the permanent zone. In most individuals, this lies at the level of the external occipital protuberance, at the midline, and the superior nuchal ridge, as one moves laterally. The trapezius muscle, the most superficial muscle of the nuchal area, originates from the superior nuchal line and the ligamentum nuchae. Incisions that lie below the nuchal line will thus be affected by the muscle movement directly below it and have a greater tendency to stretch. This problem is exacerbated when a deep donor scar obliterates the subcutaneous layer and muscle movement in the neck is more directly transmitted to the overlying skin.

It has been advocated by some that wide donor scars can be treated with re-excision in conjunction with aggressive undermining, and possibly tissue expansion. However, even the conservative re-excision of a widened scar that is located in the inferior portion of the occipital scalp carries a significant risk of healing with an even wider scar. Scars in this area should not be re-excised and, if additional transplants are performed, hair should be harvested from an incision made above it in the mid-permanent zone, leaving a thin zone of hair separating the upper and lower incisions. Instead of attempting to remove a difficult scar, its appearance may be more consistently improved by the addition of small amounts of hair to the area, with far less risk.

Donor Incisions Placed Too High -

When a donor incision has been placed too high, it is best left untreated unless the scar is wide and poor surgical technique has been identified as the cause. Often, the surgeon who used poor judgment in placing the wound too high did an equally poor job in the closure. In this case, there is a reasonable chance the scar may be improved with better techniques. As with other scars, one should generally attempt to lessen or improve the appearance, rather than trying to remove the scar entirely.

The temptation to add hair into a high scar should be resisted, as progressive balding would isolate the hair-bearing scar and present new cosmetic problems, demanding additional hair. An exception to this is placing hair into the lower portion of a vertical scalp reduction scar that dipped way down into the permanent donor fringe.

Implantation of Hair -

When a localized area of a donor scar is cosmetically bothersome, its excision is impractical, and there is easily accessible donor hair in other areas, it may be beneficial to place hair directly into the widened donor scar. Two and three-hair follicular units are the most useful for this purpose and should be inserted at very acute angles. Only a small amount of hair is generally needed to soften the appearance of a scar. Dedicating too much hair for the purpose is unnecessary and wasteful. It appears that grafts do not grow well when the scar is hypertrophic, and it is best to manage these scars with intra-lesional corticosteroids, 5-fluouracil or silicone gel sheeting, before attempting to add hair.

Conclusion -

The “science” in hair restoration surgery involves the ability to mimic nature as closely as possible, by carefully matching the newly transplanted hair to the patient’s original hair in its distribution and growth pattern. Once these principles have been violated, a standardized approach will no longer suffice in restoring the person’s normal appearance. Presented with dramatic cosmetic defects, a severely limited donor supply, and an exasperated patient, the surgeon attempting a repair faces a set of challenges quite different from those encountered when operating on a virgin scalp.

In corrective surgery, the judicious use of every graft is critical and setting surgical priorities is as important as the technique itself. In repair work, the routine, symmetrical placement of grafts will often not be sufficient to accomplish the patient’s goals. The surgeon must find ways to transform harsh walls of hair into soft hairlines and make small quantities of hair camouflage larger areas. The surgeon must be able to tap every bit of harvestable hair from the donor area and even reuse hair from previously transplanted grafts. To achieve the best results, the creative use of every follicular resource is required. This is the “art of repair.”