You are in: eMedicine Specialties > Dermatology > SURGICAL Hair Transplantation: Follicular Unit Transplant MethodArticle Last Updated: Sep 30, 2005AUTHOR AND EDITOR INFORMATIONSection 1 of 10
  Author: Bobby L Limmer, MD, Professor, Department of Dermatology, University of Texas Health Science Center Bobby L Limmer is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Cryosurgery, American Medical Association, American Society for Dermatologic Surgery, and Texas Medical Association Editors: R Stan Taylor, MD, Professor of Dermatology, University of Texas Southwestern Medical School; Director of Skin Surgery and Oncology Clinic, Department of Dermatology, University of Texas Southwestern Medical Center; Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA; John G Albertini, MD, Dermatologic Surgery, The Skin Surgery Center; Joel M Gelfand, MD, MSCE, Medical Director, Clinical Studies Unit, Assistant Professor, Department of Dermatology, Associate Scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania; Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center Author and Editor Disclosure Synonyms and related keywords: androgenetic alopecia, baldness, follicle transplant, hair loss, hair transplant, surgical hair restoration INTRODUCTIONSection 2 of 10
  Surgical hair restoration has followed a logical course to follicular unit transplantation. The concept of redistributing hair in naturally occurring units of 1-4 hairs exactly as nature grows it should have been recognized and used by the hair transplant community earlier than 1988. The finding that hair grows in naturally occurring groupings of 1-4 (and rarely, more hair) has been known for many years. The histopathologic definition of the follicular unit was defined clearly by Headington in 1984.1 Nevertheless, modern surgical hair restoration techniques ranging from Orentreich's2 description of punch autografting in 1958 to Limmer's3 first use of follicular units in 1988 were completed via unnatural groupings of nature's building blocks, resulting in a recognizable pluggy product. By definition, follicular unit transplantation is the redistribution of naturally occurring follicular groupings (follicular units) to the bald zone. The groupings are removed from the donor area by single-bladed elliptical excision and carefully and microscopically dissected beneath the binocular stereoscope. The donor tissue is trimmed into follicular units, removing the bald tissue between the units that contains no hair follicles. Then, the follicular units are reimplanted into the bald recipient zone using a needle tunnel or small slit incision. To minimize damage to the recipient vascular supply essential to the survival of grafts, bald tissue is not removed from the recipient zone. Relatively dense packing during the first session is usual (20-30 grafts per cm2) to create a cosmetic result that can stand on its own if no further procedure sessions are completed. This methodology is unique among hair restoration procedures because of the following:
Other methods of transplantation group the naturally occurring follicular units into unnatural-appearing aggregations (clumps, tufts, plugs), always resulting in an unnatural tufted visibility of the final product, which requires multiple additional sessions to hide the unnatural appearance. Such restoration procedures include standard round or square plugs and all forms of minigrafts (round, square, triangular, oval slots, linear slits, strip grafts). Flaps move follicular units in their original form but do so at great cost in terms of limited coverage, possible substantial donor and recipient site scarring, risk of partial or total flap necrosis, and highly inefficient use of precious and irreplaceable donor hair. Such donor hair may be used more effectively to cover larger bald zones as male pattern baldness (MPB) progresses, which is the natural history of this process. History of the ProcedurePioneering work in modern human hair restoration surgery by Okuda,4 Tamura,5 and Fujita6 largely remained unrecognized until the work of Orentreich2 in 1958 became the basis for worldwide restoration methodology. The punch autografting methodology of Okuda and Orentreich became the world's standard for hair transplantation with few changes over 30 years. Nordstrom7 and Marritt8 added micrografting to improve the aesthetics of the frontal hairline, and Bradshaw quartered plug autografts to produce minigrafts. Stough9 changed the pattern to slit minigrafts, and Vallis introduced the multibladed knife to donor harvesting during the 1980s. The quantum leap to total micro/minigrafting should be credited to Uebel, who simultaneously introduced single-blade donor harvest with rapid graft production and insertion methods, limiting the grafts to micrografts and small minigrafts. The Uebel10 method remains one of the most popular methods of hair transplantation and currently is used by many hair restoration surgeons worldwide. Recognizing that normal hair growth occurs in groupings of 1-4 terminal and 1-2 vellus follicles referred to as follicular units, Limmer11 developed the methodology of follicular unit transplantation, which subsequently was adopted and popularized by Rassman, Bernstein,12 Seager,13 Norwood,14 and others. When properly performed, follicular unit transplantation consistently and predictably produces the most natural-appearing surgical hair restorations. ProblemAndrogenetic alopecia (MPB) is a progressive disorder of loss of hair of the dorsal scalp sparing the lateral and occipital fringes. The degree of loss is determined genetically and produced hormonally by the androgenic hormones testosterone and dihydrotestosterone. Starting after puberty, the disorder may require from a few to 40 or more years to establish the genetically coded pattern. When planning surgical hair restoration, it is essential to plan and design procedures anticipating that the patient may progress significantly in baldness pattern. This especially is important in youthful candidates who have not had time to define their genetic pattern fully. Failure to properly plan for future loss may result in unnatural patterns as baldness progresses and surrounds previously grafted areas. FrequencyApproximately 70% of adult American males develop some degree of MPB. Hamilton15 was the first to classify MPB in 1949. Norwood used Hamilton's data and organized his own evaluation resulting in a system that currently remains in use. The classification system is helpful in planning procedures and forms the usual basis for discussion of the degree of alopecia present. Approximately 30% of cases of MPB progress to patterns VI and VII. INDICATIONSSection 3 of 10
Hair restoration to alopecic zones is an elective option. Only patients who lack adequate donor hair to reach their goals and are unwilling to compromise those goals to be compatible with available donor hair are unsuitable candidates. Because results of follicular unit transplantation methodology are natural and predictable, few candidates with realistic goals need to be excluded. CONTRAINDICATIONSSection 4 of 10
Unattainable and unrealistic goals based upon degree of alopecia and available donor hair are an absolute contraindication. Young age, psychological instability, and coexistent medical problems that may influence healing or predispose the patient to bleeding and infection are relative contraindications. WORKUPSection 5 of 10
Lab Studies
TREATMENTSection 6 of 10
Medical therapyBoth topical minoxidil (Rogaine 2%, 5%) and finasteride (Propecia 1 mg) are useful adjunctive treatments when combined with surgical restoration in men. Such therapy helps prevent or retard further loss and may induce new hair growth in some individuals. The best candidates for potential benefit are patients with large numbers of miniaturized hair present. Topical minoxidil and antiandrogens may benefit selected females. Spironolactone is the antiandrogen used most commonly. Preoperative detailsPlanning and design The midpoint of the frontal hairline is designed to fall approximately 8-9 cm above a horizontal line drawn through the center of the patient's eyebrows. Then, the hairline is gently curved laterally and superiorly toward the temporal lateral fringe. This curvilinear portion of the hairline may rise gently above, but should not be designed below, the horizontal plane. Depending on the existent lateral fringe, the hairline may be connected to this temporal fringe. When creating an isolated frontal forelock, it is best to design a central area of density and surround it by a feathering of grafts along the perimeter. This provides a more natural appearance even as hair loss progresses. When designing for crown restoration, the potential for progression of alopecia surrounding the grafted zone must be weighed carefully. While an isolated frontal forelock is an acceptable restoration and a naturally occurring process in many patients, a central crown restoration surrounded by an alopecic halo of bald scalp is not, and it represents an unacceptable consequence of inadequate planning. Transplants should mimic the natural pattern and growth direction of normal scalp hair. Donor area The density of the hair in the donor site is important to determine during planning to acquire the desired number of grafts. The donor area first must be clipped, and the number of follicular units per cm² counted. This can be achieved by using a densitometer (magnified field of 10 mm²) or by counting 4 positions along the donor site with a 10-power dermatoscope and a 5-mm² window. Because each follicular unit represents a graft, the number of cm² of donor surface area required to achieve the desired numbers of grafts is a simple mathematic calculation. In Caucasians, the average scalp has between 90-100 follicular units per cm² with a range of 50-140. Care must be taken to use donor hair from the zone not predisposed to future loss. Intraoperative detailsDonor area The number of cm² in the donor surface area required to produce the desired numbers of grafts is marked. The width of the donor excision may range from 0.7-1.5 cm depending on surgical design. Removal is performed using a single-blade knife and closure accomplished with single or double layer suture or staple technique. Graft dissection Once the donor tissue has been removed, it is kept in chilled saline over frozen packs to maintain a cool temperature while the tissue is dissected. To maintain graft viability, it is important to keep the grafts from becoming dehydrated or heated. The grafts are dissected under a binocular microscope using a minimum magnification of 10X. Sterilized tongue blades placed over an autoclavable glass cutting plate create a cutting surface for the tissue. Assistants use jeweler's forceps to apply traction while cutting with a standard double-edged razor blade or knife. Donor tissue first is reduced to thin wafers or slivers containing only a few follicular units. Then, these slivers are cut into follicular units and trimmed of excess bald tissue. The use of a binocular microscope provides minimal transection of follicles during the dissection process and dense packing in the recipient area, since minimal amounts of donor tissue are regrafted along with the follicular units. The ability to create greater density within the recipient zone as a result of the small size of the grafts is the key to follicular unit hair transplantation. The dissection process is undeniably the most labor-intensive portion of the process and requires 2-3 graft-dissection assistants for every 1 implanting assistant. Graft implantation During the implantation stage, the follicular unit grafts are placed into the anesthetized recipient zone using small punch holes (0.75-1 mm), small slit incisions (1-2 mm in length), or needle tunnels made by 19- to 22-gauge needles. If using the punch or slit methods, the recipient sites may be made prior to beginning the implantation process. The needle tunnel technique, also referred to as the stick-and-place method, requires that each graft be placed immediately after the needle has been removed, since the needle tunnel remains open only for a few seconds. An 18-gauge needle is preferred for implanting 3-4 hair grafts, while 19- to 20-gauge needles are used for implanting 1-2 hair grafts. The stick-and-place method provides greater density of follicular units within the recipient zone and causes the least trauma to the vascular system in that area. Thus, this is the method of choice for some physicians. Because of the smaller size of these grafts, it is important to handle them with extreme care and to keep them hydrated at all times. A goal of 20-40 follicular unit grafts per cm² is reasonable and readily achieved by skilled assistants. Postoperative detailsOnce the implantation process has been completed, the recipient surface is cleaned using chilled saline spray. The use of a postoperative dressing is optional. A moist surface speeds up the healing process. Repetitive wetting of the surface with saline or special solutions, such as copper peptide (GraftCyte), or ointments can maintain a moist surface. Allowing the graft surfaces simply to dry and heal without dressings is the method of care used most commonly. COMPLICATIONSSection 7 of 10
Complications are rare and seldom threatening. Postoperative bleeding and infections are unusually rare. Donor suture lines occasionally may spread and are more prone to do so if closure is performed under tension. During the regrowth phase that occurs between 30-90 days postoperatively, pustules may form in the grafted zone, which are believed to represent a pseudofolliculitis phenomenon of regrowth. A rare furunculoid lesion or epidermal inclusion cyst may occur at the site of a buried graft. OUTCOME AND PROGNOSISSection 8 of 10
The goal is to make the final product look so natural that it cannot be distinguished as a transplant. The tight packing of grafts provided by microscopic dissection generates a natural appearance acceptable to most patients. Although this method is time and labor intensive, the results justify the meticulous attention to detail. MULTIMEDIASection 9 of 10
REFERENCESSection 10 of 10
Hair Transplantation: Follicular Unit Transplant Method excerpt Article Last Updated: Sep 30, 2005 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
