Archives for May 2017

In strip harvesting, doctors take strips of hair-bearing tissue from part of the head and place them elsewhere, while with FUE – follicular unit extraction, doctors take follicular units of one to four hairs instead of entire strips, and transplant them elsewhere on the head. 

In this second article of the three-part series we will talk about graft survival, graft placement and graft numbers. 

Graft Survival

Debate exists over the rate of survival using FUE versus strip grafts. There is some concern that since FUE grafts may have very little tissue surrounding them, they are less likely to survive. Such grafts are more prone to dehydration, which has been shown to be a major cause of diminished graft survival. The lack of tissue surrounding the hair follicle is often a result of “pulling” on the graft to remove it. Because there is added manipulation in trying to remove a graft this may also contribute to diminished survival.

With FUE hair transplants there is a greater chance of damaging hairs as compared to strip harvesting, and this could result in poor growth or lack of growth depending on the level of damage. The rates of damage seem to vary widely with FUE. Conversely, with strip harvesting, grafts may be damaged in making the initial skin incisions and subsequent dissection of the tissue, but this is considered minimal. The use of the microscope for dissection of the donor strip should limit damage rates to 1-2{acd4a358aa854be283d148c7810f1013831bd5d6bf73206c5f743beae9259ccd}. Grafts created with strip harvesting generally have a greater amount of surrounding tissue and fat. This may decrease the chance of dehydration and allow for greater leeway in manipulation of the grafts during placing and hence, better graft survival.

Placing of Grafts

When manual placement of grafts is used there is no difference between the two techniques. There may be some concern about the fragility of FUE grafts and the fact that they may be more susceptible to drying.

Perfectly harvested grafts may be damaged during the placement phase and fail to grow. Trauma and graft drying are well known factors that may occur in inexperienced hands and will impact graft survival. Regardless of how grafts are harvested, there is a considerable amount of artistry and technical expertise necessary to place them to produce an excellent or even acceptable result. The surgeon must be able to create an aesthetic “blueprint” for graft placement, determining the distribution of 1, 2, and 3 hair grafts. Hairline design is obviously important, as is the grafting plan over the rest of the scalp.

Number of grafts per session

In general most physicians who perform FUE hair transplants cannot do as many grafts in a single session they can with strip harvesting. With strip harvesting, sessions of 2000-3000 grafts are very common and some physicians frequently perform sessions in excess of 4000 grafts. There are, however, exceptions and some physicians, routinely performing FUE, report similar in excess of 2000 grafts.

It is estimated that 35 million men in the United States are affected by male pattern baldness or androgenetic alopecia. “Andro” refers to the androgens (testosterone, dihydrotestosterone) necessary to produce male-pattern hair loss (MPHL). “Genetic” refers to the inherited gene necessary for MPHL to occur. In men who develop male pattern baldness the hair loss may begin any time after puberty when blood levels of androgens rise. The first change is usually recession in the temporal areas, which is seen in 96 percent of mature Caucasian males, including those men not destined to progress to further hair loss.

Hamilton and later Norwood have classified the patterns of male pattern baldness (see illustration below). Although the density of hair in a given pattern of loss tends to diminish with age, there is no way to predict what pattern of hair loss a young man with early male pattern baldness will eventually assume. In general, those who begin losing hair in the second decade are those in whom the hair loss will be the most severe. In some men, initial male-pattern hair loss may be delayed until the late third to fourth decade. It is generally recognized that men in their 20’s have a 20 percent incidence of male pattern baldness, in their 30’s a 30 percent incidence of male pattern baldness, in their 40’s a 40 percent incidence of male pattern baldness, etc. Using these numbers one can see that a male in his 90’s has a 90 percent chance of having some degree of male pattern baldness.

Hamilton first noted that androgens (testosterone, dihydrotestosterone) are necessary for the development of male pattern baldness. The amount of androgens present does not need to be greater than normal for male pattern baldness to occur. If androgens are present in normal amounts and the gene for hair loss is present, male pattern hair loss will occur. Axillary (under arm) and pubic hair are dependent on testosterone for growth. Beard growth and male pattern hair loss are dependent on dihydrotestosterone (DHT). Testosterone is converted to DHT by the enzyme, 5¤ -reductase. Finasteride (Propecia®) acts by blocking this enzyme and decreasing the amount of DHT. Receptors exist on cells that bind androgens. These receptors have the greatest affinity for DHT followed by testosterone, estrogen, and progesterone. After binding to the receptor, DHT goes into the cell and interacts with the nucleus of the cell altering the production of protein by the DNA in the nucleus of the cell. Ultimately growth of the hair follicle ceases.

The hair growth cycle is affected in that the percentage of hairs in the growth phase (anagen) and the duration of the growth phase diminish resulting in shorter hairs. More hairs are in the resting state (telogen) and these hairs are much more subject to loss with the daily trauma of combing and washing. The hair shafts in male pattern baldness become progressively miniaturized, (see hair follicle miniaturization illustration) smaller in diameter and length, with time. In men with male pattern baldness all the hairs in an affected area may eventually (but not necessarily) become involved in the process and may with time cover the region with fine (vellus) hair. Pigment (color) production is also terminated with miniaturization so the fine hair becomes lighter in color. The lighter color, miniaturized hairs cause the area to first appear thin. Involved areas in men can completely lose all follicles over time. Male pattern baldness is an inherited condition and the gene can be inherited from either the mother or father’s side. There is a common myth that inheritance is only from the mother’s side. This is not true.

In summary, male pattern hair loss (Androgenetic Alopecia) is an inherited condition manifested when androgens are present in normal amounts. The gene can be inherited from the mother or father’s side. The onset, rate, and severity of hair loss are unpredictable. The severity increases with age and if the condition is present it will be progressive and relentless.

Hair loss in men is likely to occur primarily between late teen-age years and age 40-50, in a generally recognizable “male-pattern” baldness known as androgenetic alopecia. Men with male-pattern hair loss may have an expectation of hair loss if they have male relatives who lost hair in a recognizably male pattern.