This is a question from an hair transplant doctor to Dr. John P. Cole:

Dear Dr. Cole, I recently did a procedure of FUE where I felt like 1450 grafts was all I could harvest.  I felt like I could have gotten more grafts doing a strip procedure.  I’ve enclosed a photograph of my patient for you to review.  How do I get more grafts doing FUE hair transplant since I am new to doing FUE procedures?

One must have knowledge to talk or think learnedly about any matter. You cannot possibly have a clue as to your potential follicular unit harvest numbers without knowing the patients pre-operative density. You might have a clue as to your potential strip graft numbers only through experience. With a lack of experience, the only way to predict your graft density with FUE is to first determine the follicular unit density in the donor area.

My method is to first subdivide my donor area in 14 distinct boxes. I have 8 major boxes and 6 minor boxes. I have four major boxes to the right (numbered 1-4) and 4 major boxes to the left (numbered 5-8). Boxes 1 and 5 are in the midline and measure 3.5 X 5 cm. Boxes 2-4 and 6-8 measure 3.5 X 6 cm. I measure the FD in each box and multiply this by the surface area. This gives me a predicted total FD in each box.

When I harvest, I note the extracted number of grafts in each box. In this manner I can assess the total percentage of extracted grafts for each box and the total percentage extracted over a case. It is very common to be able to extract between 250 to 350 grafts in each box. In cases of poor FD, you may harvest only 150 to 200 grafts. In cases of exceptional FD, you may harvest over 500 grafts from some of the boxes.

I¹ve enclosed an actual example. As you can see I harvested very few grafts from the lower, minor boxes and a total of 17.2% of the donor area. I can push this much harder if I want to up to about 25% in a single pass.

When you remove a strip, you remove surface area and volume from the donor area. You then must close this defect with less skin and fewer follicular units. You accomplish this by stretching the skin. This stretch necessarily reduces the follicular density (FD). There is some stretch back mostly in the first 0.5 cm on either side of the strip and part of the void is filled by scar, but the general process is to reduce the FD by asking the remaining FU to do more work.
This reduces the cross sectional trichometry partly due to stretch and partly due to scar formation. In a perfect scar the remaining follicles have to cover more area than with a wider scar because they have to cover the full defect rather than having scar do some of the work.

Strip removal causes a tightening of the donor area so you wind up with fewer grafts in the second procedure due to a lower FD, tighter donor area, and scar formation (provided you excise the same scar with a subsequent procedure).

With FUE, you remove FU. This reduces the cross sectional trichometry. However, FUE results in a compression of the donor area so that the reduced number of FU in the safe donor area have to cover a smaller surface area rather than the same surface area. This results in an often higher CST for the same number of grafts harvested. In other words, strips lower the donor area hair mass more than FUE does.

Hair mass is a function of donor area surface area (more hair loss means less donor area), hair diameter, and density of both the FU and hair. Those with more hair mass can expect more coverage. Those with a lower hair mass can expect less coverage. Those with less hair loss can expect more optimal results than those with advanced degrees of hair loss.

Hair mass potential before surgery is no different when you do a strip or FUE. The real question is which procedure offers a higher hair mass transfer in real life experience. Is it strip? Is it FUE? Or is it a combination. Which procedure causes a greater decline in the donor area CST? I think you
know my answer and I think I know your answer, which is the same answer all strip surgeons have. I don¹t  think anyone will be convinced without objective data. I¹m not prepared to visit the offices of Dr. Nagsaki or Dr. Hiroshima yet, but the time is coming. The American Prometheus is preparing the knock out blow.

You hardly over harvested this donor area, yet you obtained 1450 grafts. There is no question that you could have exceeded 2000 grafts. Obviously, it is hard to see all the FU in this donor area primarily because the hair is light in color. The next time you prepare a donor area like this, first use some sort of hair dye to give the follicles more pigment. I typically use Just for Men. Then buy yourself a donor template from me and use it to mark up you donor area.
Alternatively, draw it in by hand. Then evaluate your donor area density for each box and estimate your total follicular unit density. Finally, aim for a harvest of about 19 to 20% in each box. If you can¹t reach this level, then don¹t knock FUE. Just get back on your horse and try again the next time. When you can reach 20%, try for 25%.

We all know the theory that you have to loose 50 1Ž2 your hair before you look thin. Well, many can loose far more than 50% and still look full except in the crown area where thinning is apparent around 50% loss (the reason is due to the spiral direction changes in the crown). In the donor area, removing over 50% will make the donor area thinner, but it will still look full. Often you can take over 50% of the FU without making the donor area exceptionally thin. What you have to watch out for is thinning the safe area more than the surrounding areas because the surrounding areas will look thinner than the safe area.
You may need to thin some of the surrounding areas to make the overall product similar. That leads us into a totally different topic, which is what is the safe donor area? My opinion is that it varies from one patient to another and you can¹t make generalizations because many will never advance beyond a NW 3V. These individuals certainly have a much larger safe donor area than those who head to a NW 6 or 7. I”ll save this debate for a later time.