Hair Transplant Terms & Definitions D-L
Dermal Papilla – DP are part of the uppermost layer of the dermis. Blood vessels in DP provide oxygen and nutrients to hair follicles.
Dermis – The second layer of skin on our bodies.
- Dihydrotestosterone (DHT) is a derivative or by-product of testosterone. Testosterone converts to DHT with the aid of the enzyme Type II 5-alpha-reductace. The full genetic process of male pattern baldness is not completely understood but we do know that DHT shrinks hair follicles that have DHT coded receptors at the cellular level and when DHT is reduced hair follicles continue to grow without signs of miniaturization. Prescription medication can slow or stop this process if caught early enough.
Dilators – A technique to enlarge a recipient site for easier hair transplant graft placement due to increased visual recognition. Invented by Dr. Emanual Marritt, Dr. Marritt, and eventually many other doctors at the time, used toothpick like instruments to insert into freshly made recipient sites in order to better see where the incisions were made prior to placement of prepared grafts. Patients with multiple hundreds of incisions made and with dilators in place have been compared to “pin cushions” or “cushion heads”. It was later thought that the expansion of scalp tissue from such dilators caused more damage than necessary and eventually the practice of using dilators has stopped.
Donor – With reference to hair restoration the donor, also known as the “safe donor” or “donor zone” is the area at the back and sides of a person’s scalp that has hair considered to be safe for surgical transplantation. This hair is traditionally considered to be resistant to dihydrotestosterone (DHT) but it is not 100% guaranteed that this is the case for all people. Some hair in the donor zone can and is susceptible to DHT.
Donor Dominance - Dr. Norman Orentriech discovered donor dominance in 1952 when he successfully transplanted hair from the DHT resistant tissue in the back of the head to a patient's balding area. Tissue taken from the safe zone retains characteristics of that area and remains resistant to DHT so hair is permanent for life. This principal is called donor dominance.
DPA - DPA stands for Diffused Pattern Alopecia. This is a type of hair loss that does not progress to the point of complete loss in any given area but rather introduces a general thinning over one of the recognized patterns of hair loss as found in the Norwood chart.
DUPA - Diffused Unpatterned Alopecia is a type of diffused hair loss that permeates throughout the entire scalp and is considered untreatable by surgery because the thinning progresses into the traditional safe zone thereby rendering hairs in the safe zone to be unreliable for transplantation.
Dutasteride – A 5 – Alpha Reductase (5αR) inhibitor. This is a newer medication than Propecia/Proscar (finasteride) and is still only approved for prescription for the treatment of benign prostate hyperplasia (BPH) but is commonly prescribed “off label” for hair loss prevention. The market name is Avodart and is manufactured by Glaxo-Smith-Kline Pharmaceuticals. Dutasteride blocks both 5αR enzymes, type I and type II.
Epidermis – The outermost layer of skin, the skin that you see on your arm, your face, etc.
Finasteride – The generic name for medication known as Propecia (1mg) and Proscar (5mg) in North America and Europe, manufactured by Merck Pharmaceuticals. Finasteride is available in generic form 5mg in North America and manufactured through international licensing by other pharmaceutical companies in 1mg and 5mg dosages.
Follicular Unit - Hairs do not always grow as single hairs isolated from each other. Hair tends to grow in groups or bundles called follicular units. These are hairs that grow very close to each other or even out of the same exit point and appear as clusters. They consist of two, three, four and sometimes five hairs per bundle. Single isolated hairs make up approximately 20% to 30% of all hair growing on the scalp depending on ethnicity and hair type.
Follicular Unit Transplant (FUT) - This has two definitions.
1. The original meaning refers to the introduction of stereoscopic dissecting microscopes for use in separating follicular units out of the donor strip tissue. This was introduced by Dr. Limmer of San Antonio, Texas USA in 1994 and became the gold standard worldwide for nearly twenty years. By using stereoscopic dissecting microscopes the yield from FUT procedures increased on average of 30%. With proper trimming through the use of microscopes the grafts implanted are thinner, requiring smaller incisions thus allowing for higher placement densities and less overall trauma to the recipient scalp.
2. "FUT" currently refers to strip surgery in general to distinguish between strip surgery and FUE surgery. Technically this is an incorrect use of the term as it can refer to strip surgery or FUE surgery because both procedures transplant follicular units. A more appropriate term to reference strip surgery would be Follicular Unit Strip Surgery or "FUSS" as originally described by Dr. Alvi Armani in the late 1990's.
Follicular Unit Extraction (FUE) - Removal of each bundle or follicular unit individually with a small punch device. Technically, FUE was invented in Japan in the late 1930's by Dr. Okuda but the details of his work were lost during WWII. Dr. Tamura, a few years after Okuda, is reported to have used smaller punches more similar to what is used today but this is still in dispute due to lack of documentation. Dr. Ray Woods of Australia is the recognized inventor of modern FUE as we know it today. FUE is becoming the preferred method of hair restoration for most patients due to the lack of the linear scar common to patients of strip surgery. FUE will leave scars as tiny white dots allowing the patient to have shorter hair styles in general when compared to strip surgery patients. This is highly dependent on various factors such as healing characteristics, hair density, scalp color, ethnicity etc. but even with visible dot scarring the visible result has less cosmetic impact than with strip surgery. FUE can be performed manually by hand, with a motorized punch or more elaborate automated or robotic systems.
FUSS - Follicular Unit Strip Surgery, the more correct acronym to describe strip surgery.
Graft – A piece of hair bearing tissue transplanted into the scalp. Grafts can be taken from all areas of the body or scalp and the size and refinement of grafts is determined by the technology, tools and overall approach taken. The term “graft” is a general term and includes plugs, mini-micro, follicular units, multi-units, body hair, etc.
Gynecomastia – Sometimes referred to as “gyno”. It is a condition in which male breast tissue is enlarged causing tenderness and visually noticeable swelling. Gyno has been attributed to the use of finasteride, dutasteride and other 5αR medications and is listed as a rare but potential side effect.
Hair Flap – A surgical procedure in which the surgeon moves a “flap” or strip of hair bearing tissue from either side of the scalp and inserts it into the anterior region of the scalp. This creates a new hairline that has native hair density with immediate results. The procedure is extremely invasive and has a high potential for post-operative complications. Final results have mis-angled hair direction and potential obvious scarring along the frontal hairline region.
Hair Geometry – This is in reference to the natural direction of hair growth. All hair growth directions radiate out from a central point in the crown whorl, usually in a clockwise fashion. The whorl or rotation pattern is tightest at the center of the crown and as the rotation moves outward the direction of growth loosens or relaxes. The left side of the scalp usually sees hair growing in a fairly forward direction toward the anterior scalp and the right side of the scalp usually grows in a backward direction to the posterior of the scalp, completing the rotation. Hair on the back of the scalp tends to grow down and slightly to the left of center and hair on the top of the scalp tends to grow forward toward the hairline with a slight deviation to the right.
Hair Transplant - This is a general term. It involves the act of transplanting hair from one part of the body to another. The term is normally associated with transplanting hair from the traditional safe donor zone of the scalp to an area of the scalp that has become thin or bald for the purpose of restoring lost hair.
Hypertrichosis – Excessive scalp and body hair growth, also called Ambras syndrome.
Hyper Thyroid – Thyroid deficiency that can cause hair loss. It is typically one of the tests suggested to investigate female hair loss.
HypoThermosol – A solution used in the storage and transport of living tissue. For hair restoration it is gaining traction to become the standard storage solution for follicular units after removal from the scalp or scalp tissue while they await implantation into the recipient scalp.
– This is a device used for the implantation of follicular unit grafts into the recipient scalp. It was first developed and used by Yung Chul Chou of Kyungpook National University in South Korea in the early 1990’s. It is designed to reduce the number of movements necessary to place a FU into the recipient scalp and is also designed to reduce the amount of direct physical contact between practitioner and transplant tissue. Implanter pens also help to reduce the amount of time that a follicular unit is outside of the body. Once a prepared graft is loaded into the pen a hyperdermic needle simultaneously makes the recipient site incision and loads the follicular unit into the incision. This is known as simultaneous stick and place. There are two types of implanter pens. The Choi Implanter and the Lion Implanter. The Lion Implanter is a modification on the Choi implanter as it is designed to allow for faster needle replacement as the needle tips become dull due to repeated use during surgery.
Keratin – It is the key component that makes up hair and nails.
Ketoconazole – An anti-fungal compound available in multiple forms. It is available topically as a cream or in various dandruff shampoos in 1% and 2% dosages. Multiple studies have shown ketoconazole to be as effective against hair loss as 2% Minoxidil.
Langer’s Lines – Sometimes called “Cleavage Lines” they are lines drawn on the human body used to represent the natural orientation of collagen in the dermis. Specifically, cosmetic surgeons will try to make incisions along Langer’s Lines as wounds tend to heal better and with less visible scar tissue. On the scalp, Langer’s Lines tend to line up from the posterior scalp to the anterior scalp.
Lateral Slit Technique – A technique for recipient site creation originally envisioned and developed by Dr. Jerry Wong in Vancouver Canada. Lateral slits are incisions into the recipient scalp with custom cut flat blades placed perpendicular to the direction of natural hair growth which, for the most part, follows the Langer’s Lines of the scalp. The nature of the incisions allow for a stronger degree of control for angle and direction of graft placement and they encourage multi-hair follicular units to spread thus giving better overall coverage than grafts placed into sagittal incisions. Commonly, but mistakenly, confused with coronal slits the lateral slit technique, by definition, requires the use of flat blades and while the incisions are parallel to the direction of growth the this direction will deviate from one recipient zone to the next based on the natural flow of hair growth in different regions.
Latisse – Market name for bimatoprost. It is an eyelash growth or thickening treatment that some belive has the potential to be the next topical agent for male pattern hair loss and female pattern hair loss.
Laxity - Laxity, or "scalp laxity", is the vertical movement of the scalp. When hair restoration surgeons are assessing the candidacy of a patient for FUSS they measure the donor density and the donor laxity. In this regard, the measurement is determined by the distance of vertical movement, both in the posterior scalp and the lateral scalp as this determines the width of the donor strip to be taken for harvesting. The greater the laxity, the more scalp can be removed, thus more hair can be harvested for a stronger cosmetic impact and final result.
Loniten -Loniten Tablets contain minoxidil, an antihypertensive peripheral vasodilator. Minoxidil occurs as a white or off-white, odorless, crystalline solid that is soluble in water. Loniten tablets contain the very strong antihypertensive active ingredient known as Minoxidil (same active ingredient in Rogaine) which can cause serious adverse effects. It can cause pericardial effusion, which sometimes can turn into tamponade, and it may antagonize existing cases of angina pectoris.
Ludwig Scale - One of two widely used charts to measure female hair loss.
Terms & Definitions A-C