The Exclusive Use of Slit Mini-Micrografting for the Correction of a Large Frontoparietal Scalp Defect

In this article slit mini-micrografting is used exclusively for the correction of a large frontoparietal scalp defect. This method was used as an alternative to tissue expansion, transposition-rotation flaps, free flaps, or conventional punch hair-grafting. The protocol consisted of three well-organized sessions of #15 blade and 18-gauge needle slits made very obliquely into the scarred defect. Mini- and micrografts were then placed into these incisions. This approach yielded a good result which was felt to be due to the combination of the minimal trauma caused by slits and the limited circulation required for the survival of mini- and micrografts. Minigrafts were also much easier to insert into scar tissue when compared with conventional grafts. In conclusion, it was felt that the exclusive use of slit mini-micrografting appears to be a viable method for the correction of frontoparietal cicatrial alopecia.

In the early twentieth century, flap techniques were developed by innovative surgeons as the first viable treatment for large scalp defects. Among these early pioneers, Cushing¹ is generally credited with performing the first closure of a scalp defect with three advancement flaps in 1908. Later, Dufourmenel in 1919², Mitchell in 1933³, Gillies⁴ in the 1940s, Kazanjian in the 50s⁵, and Orticochea in the late 60s^6,7 developed more intricate flap techniques for the treatment of cicatrial alopecia. Over the last 15 years, tissue expansion techniques have significantly enhanced these flaps by allowing them to cover much larger areas^8,9 Even more recently, microsurgical free flaps^10,11 have given surgeons still another tool for effectively reconstructing scalp defects.

On the opposite spectrum, Okuda¹² demonstrated in 1939 that hair transplantation could be used for the treatment of scarring alopecia. Years later, Burke et al.¹³ in 1966, Stough et al.¹⁴ in 1968, Nordstrom¹⁵ in 1979 and Resnik¹⁶ in 1984 also wrote papers describing effective treatment of scarring alopecia with 4.0-mm to 4.5-mm punch hair-grafts. Although these rather large punch-grafts (15-25 hairs per graft) do work fairly well in scarring alopecia, there has been described some inconsistency of hair growth due to poor blood supply. For instance, Unger¹⁷ has written that 4.0-mm punch hair-grafts grow well at the periphery, but grow poorly at the center. He also noted that when normal spacing between grafts is utilized, they do not survive as well. This also seems to occur when the sessions are spaced less than 6 months apart.

MINI-MICROGRAFTING

The apparent reasons for the increasing popularity of both mini- and micrografts are four:

1. The results are more aesthetically pleasing.
2. The grafts require less nutritive circulation.
3. The recipient sites cause less disruption of the recipient vasculature.
4. There is more predictability of hair growth due to 2 and 3.

In regard to the methods used to create the recipient sites, they consist of either making small slits with blades (minigrafts)¹⁹ or needles (micrografts)²³; or by forming holes with small punches.²¹ Slits generally are felt to cause less trauma to the scalp than do holes. There are, however, many who utilize the hole technique.

In the reconstructive case to be studied in this article, slit mini-micrografting was chosen over conventional punch-grafts, transposition-rotation flaps, free flaps, or tissue expansion. The anatomical, emotional, and technical reasons for this decision are discussed in the following case study.

CASE STUDY

No attempts at reconstruction were made until the age of 12 at which time a large transpositional flap was attemptedresulting in necrosis and infection. After this occurrence, the patient wore a hairpiece up to the time that he was referred to the author for possible reconstruction.

At evaluation, the options of slow tissue expansion, free flaps and transposition-rotational flaps were discussed. The patient and his family, however, were not intrigued by these options due to the previous flap failure. Because of this reality, slit mini-micrografting was offered as a viable possibility. It was stated that the risk of the surgery was minimal; that the chance for acceptable hair growth was good; and that a softly feathered hairline could be developed with the use of micrografting. After careful consideration, the patient, along with his family, chose to undergo the slit mini-micrograft method of reconstruction.

The patient from the front view immediately before the first corrective surgery. He had several sessions of conventional punch grafting performed at a hair clinic.

METHOD

At the first session, the patient was administered a preoperative oral sedation of 20 mg of diazepam and 2 oxycodone tablets. While sedation was taking effect, the hairline was drawn in (Figure 2A), as were the necessary horizontal lines of reference (Figure 2B). These horizontal lines were crucial to keeping the staggered pattern consistent and well organized. A fusiform shape was also drawn at the most inferior aspect of the good posterior donor hair.

Figure 2A. The patient with the proposed hairline drawn in preoperatively.	Figure 2B. The horizontal reference lines are critical to keep the pattern consistent and well organized.
Figure 2C. The first session of minigrafts are growing.	Figure 2D. After three sessions of mini- and micrografts.
Figure 2E. A close up of the area that has been slitminigrafted.

Upon completion of the drawing, the patient was taken to the operating room, at which time a field block anesthesia of 2% lidocaine hydrochloride and 1:100,000 epinephrine was administered at the donor area. A quadruple blade (Robbins Instruments, Chatham, NJ)²² was then used to make three long 3-mm strips of donor hair (Figure 3). These were subsequently cut into 3.0 X 1.5 mm rectangular minigrafts. One-haired micrografts were also dissected away from these strips.

Figure 3. A schematic demonstrating the strips that were removed from the patient. These were then cut into 3.0 mm x 2.0 mm rectangular minigrafts and micrografts.	Figure 4. The incisions intraoperatively before placement of the mini and micrografts.

While these hair-grafts were being developed by the surgical assistants, the recipient area was addressed. A #15 blade was used to make incisions in a staggered pattern with each incision being separated by 6.0 mm (Figure 4). The rectangular minigrafts were later inserted into these incisions. Because the area of cicatria was exceptionally thin, it was essential to create sharp oblique back cuts into the scar so that the graft could be properly buried (Figure 5A). It is critical that the entire graft, except for its epidermis, be buried so that desiccation does not destroy the graft. On the converse, it is important that the epidermis of the graft remain above the surface (Figure 5B), so that an abnormal inverted pitted appearance does not result. Once the #15 blade incisions were completed, the hairline was refined with the random extensive use of micrografts placed into 18-gauge needle wounds.

Figure 5A. The blade is placed at a very oblique angle so that the grafts are not desiccated in the thin scarred area..

Figure 5b. It s important that the epidermis of the graft remains above the surface.

Four months after the completion of the first session (Figure 2C), the second session was performed. The donor strips harvested for this operation were taken immediately above the scar from the first operation. This scar was then excised. After closing the donor area with 0 PDS II and 3-0 Prolene, #15 blade incisions were made 2.0 mm to the right of the growing minigrafts from the first session. The appropriate needle incisions were then made randomly at the anterior hairline.

Four months later, the final session was performed. The donor strips for this procedure were taken immediately superior to the second session's scar. The scalp laxity was good, allowing the scar to be excised at this time. After suturing the donor site, #15 blade incisions were made 2.0 mm to the right of the second session of growing minigrafts. Once again, extensive random 18-gauge needle incisions were made anteriorly for hairline softening.

Six months later, the patient was reviewed and found to have a good result with all grafts achieving excellent hair growth (Figures 2D and 2E).

DISCUSSION

1. The grafts grew extremely well at the central areas of the defect as well as the peripheral areas.
2. The minigrafts were spaced close together and still grew extremely well.
3. The time interval between sessions was the normal 4 months with excellent hair growth being realized.

This varies from previous reports about conventional punchgrafts which state that large grafts do not generally grow well at the central areas of the defect; that it is necessary to allow a little more space between grafts; and that there should be a greater time interval between sessions.

Although this one case study does not speak for all cases, it does elicit the hypothetical question-"What factors would help slit mini-micrografts perform better than conventional punchgrafts in an area of cicatrial alopecia?" In the author's view there are three key factors:

1. Slits are much less traumatic than holes. Making a slit is obviously less traumatic than making a hole because much less vasculature is violated with a slit. The circumferential length of a punch incision is much longer, which obviously causes more destruction than a #15 blade incision. Finally, the act of removing skin, after creating a hole, is more disruptive than simply making a small incision.

2. Small grafts need less circulation than larger grafts for survival. Many times with larger grafts the phenomenon of doughnuting occurs, due to toxin build-up at the central portion of the graft.²⁴ Conversely, minigrafts rarely develop this phenomenon because the necessary nutrients can more readily reach the center of the graft. In an area of scarring alopecia these factors become even more crucial.

3. Small grafts are much easier to bury at an oblique angle in thin cicatrial tissue. Because scarred alopecia is usually very thin, it is more difficult to bury a large conventional graft at an oblique angle. This oblique angle is crucial to preventing the graft from desiccating.

Besides these significant advantages, the smaller grafts offer better aesthetics when compared with conventional punch-grafts. It is fairly obvious that if one implants the same number of hairs, but does it with a greater number of smaller hair grafts, the result will be more refined.

Alternatively, flap and expansion techniques could have been utilized for this patient, but a previous flap failure caused the patient to reject this approach. Regardless of this decision, it is the author's opinion that a flap and/or expansion technique would not have given this patient the refined appearance that was achieved, primarily due to the abruptness of the hairline created by flaps. On the other hand, if the defect were in a posterior area of the scalp, and not at the hairline, a flap or expansion would probably have been a superior approach.

SUMMARY

REFERENCES