DENSITY AND RESULT OF TRANSPLANT

	Asian	Caucasian	African
Density of Follicular Unit per sq. cm/ sq. inch/ sq. m. m.	60- 80 per sq. cm or 375 -500 per sq. inch or 0.8 per Sq. m. m.	100 per sq. cm or 625 per sq. inch or 1.1 per Sq. m. m.	60 per sq. cm or 375 per sq. inch or 0.65 per Sq. m. m.
Hair per per sq. cm/ sq. inch/sq. m. m.	120 – 160 per sq. cm or 750 -1000 per sq. inch or 1.6 per Sq. m. m.	200 per sq. cm or 1250 per sq. inch or 2.2 per Sq. m. m.	120 per sq. cm or 750 per sq. inch or 1.3 per Sq. m. m.
Total hair in scalp	80000	100000	60000
Total Donor graft available	Medium due to medium density and smaller size of donor	Maximum due to higher density and larger size of donor (> 35 cm x 7.5 cm = 262 cm2)	low due to low density and smaller size of donor
Donor hair character	More thickness	Average thickness but usually skin hair contrast is less esp. with blonds and light hairs	More 3 or 4 hair follicular units and curly hairs

In the head of an average male with a hair bearing area of approximately 80 square inch area,

The more the density, the more is the movable hair the number of square inches of scalp that can be moved depends upon the looseness of the scalp (something we call Scalp Laxity). The more square inches we can safely move, the more hair we can transplant

With good decision making by the doctor, large sessions should not scar more than multiple smaller sessions but there may be a cost for aggressive decisions in large session transplantation if the doctor is not experienced in such procedures. So there is a balance between what can be done and what should be done. The real issue here is not if it can be done, but whether or not they will actually grow. Various factors affect the overall outcome of the transplant are

1. Density of the hair: A doctor can transplant as high as 50% of the original density but hair transplant is not an Olympic contest of how may grafts one can place in a sq. cm. But it is certainly an issue where you have to see that how many grafts really grow. It is important to focus more in the issues of coverage and fullness. Some studies have shown that by crowding the grafts more than 40 per square cm, blood supply may be compromised & the successful growth of these grafts starts to fall off significantly. If there is hair already present in the transplanted recipient area, there is great likelihood that it would damage the existing hair as well as obtaining poor growth. Well the area of grafting is important; the hairline needs higher visual density than the area behind it for cosmetic reasons.

2. Donor Laxity: Tight scalp restricts the harvestable number of grafts in a megasession because the width of the strip that can be removed becomes restricted.

3. Donor Area size: Assuming normal density of hair, a person with the Norwood Class 7 hair loss pattern (the worst case) will lose 70% of the total hair he was born with. This will leave him with a 3 inch by 14 inch wreath of hair around the back and sides of his head. This area is less in the Asian head due to smaller size of the head both in the hight and the length.

4. Donor Scarring: More the number of surgeries done more is the donor scarring and more is the possible loss in the scarring and therefore less is the available grafts. Therefore megasessions can harvest more number of total grafts than multiple smaller sessions which lead to multiple scars.

5. Hair shaft thickness. The coarser the hair, the better it supplies bulk. Hair bulk is a critical element in producing fullness and coverage. Coarse hair is better than fine and wavy is better than straight in giving the volume or coverage. For the same coverage given by 1000 hairs of 80 micron diameter one needs 1300 hairs of 0.7 micron and 1800 hairs of 0.6 micron and 2560 hairs of 0.5 micron diameter. A blonde with white skin, may only have to return 15% of the hair density, with coarse dark hair , you might get away with 25% of your original density, and if your hair is wavy with good thichness it may be even less. On the other hand Fair skin with thin black hair may require more number of grafts to be transferred to achieve the reasonable coverage. Oriental hair with good shaft thickness has better coverage capacity compared to thin Caucasian hairs.

6. Pre existing DUPA: For an African or Asian man under 25, a donor density of 120 per sq.cm. without “DUPA-Diffuse Un Patterned Alopecia” may make a good candidate with high quality hair, while a Caucasian with he same density having DUPA might make a very bad candidate for a hair transplant for many reasons..

7. The size of the balding area. The more bald you are, the more hair you might need. Sometimes, the goals has to be more realistic due to limited supply or a demand that is too high. One with the impaired vision aims for the best possible improvement in vision by the treatment but one with the loss of both eyes should aim of a helpful stick or a faithful leading dog. Stage 7 may have bald area of 250 sq.cm or more to give coverage to that area with average density of 30 would need 250 x 30 = 7500 grafts which need at least 2 sessions to give coverage.

8. The characteristics of your hair. African hair due to its curliness has a better coverage and volume giving capacity. The Italians and French had the best wavy hair. Straight is the most challenging, as found in many Asians.

9. Color/contrast between hair and skin color. This is critically important. A Class 6 pattern blonde person could reduce his hair population to 85% of its original density and still look full as the blonde hair and blonde skin have low contrast. The same applies to black hair and black skin, brown hair and brown hair, sandy hair and sandy skin and any skin color with white hair. Salt and pepper hair works very well. It difficult to achieve good result in people with white skin with black hair.

10. Length of the hair: Longer the hair the better the coverage and fullness. I normally advise the transplant candidate to keep transplanted hair long and not very short.

11. Elasticity of Recipient: Scarred or callous scalp tissue: The health of the scalp determines just how close you can place the grafts (for scalp that is atrophic and lost its infrastructure of blood vessels, glandular structures and fat; less density is often better). The reasonable upper limit of density numbers from a transplant perspective is up to100 - 120 hairs per square cm. This type of density, however, requires supple skin that still has elastic properties. Scars do not have this characteristic. Also scars have an abnormal blood supply when compared with normal skin. Much of the infrastructure and microcirculation in the vasculature is not present in scar, so transplanting very high densities may not produce good growth.

12. Skill and Ability of the surgeon and team: to transfer this number safely the size of the instruments for making sites, the skill of the surgical team at placing grafts tightly together

13. Other Characters; emerging angle, oiliness, sheen, static electricity etc.