Bernstein Medical Center for Hair Restoration - Dense Packing of Grafts

Dense Packing of Grafts

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Q: It is my understanding that as a person loses his or her hair, the skin of the scalp undergoes a number of changes, namely there is a loss of fat, an increase in cellular atrophy, and of course the dreaded perifollicular fibrosis (now that’s a mouthful). It seems to me that these changes, in particular the fibrotic scarring, are the main obstacles in the way of regrowth, and the reason Propecia does not work for extensively bald men. What can be done about this demon we call fibrosis? Can it be slowed, stopped, prevented, reversed? If we could somehow counteract collagen formation, wouldn’t our baldness problems be solved for good? If a bald scalp is atrophic, how does it have the capacity to hold a whole new head of transplanted hair? Is there a limitation to the number of hairs we can transplant (outside of donor limitations)? — R.L., Rivington, C.T.

A: The findings that you are describing are well documented; however, it is not clear if these changes are the cause of the hair loss or are the result of having lost one’s hair. Most likely, the DHT causes the hair follicles to miniaturize and eventually disappear. This, in turn, causes the scalp to thin and lose its abundant blood supply (whose purpose is to nourish the follicles). The changes in the scalp are also affected by normal aging, which causes alterations in connective tissue including the breakdown of collagen and other components of the skin. The changes seen with aging are greatly accelerated by chronic sun exposure.

Fortunately, even with long-standing baldness there is still enough blood supply to support a hair transplant, although there are some limitations. One should perform a hair transplant with a lower density of grafts when patients have thin, bald fibrotic scalps since the blood supply is diminished.

The most important factor, however, is photo change. The sun dramatically alters the connective tissue making the grafts less secure in their sites and alters the vasculature, (blood vessels) decreasing tissue perfusion (blood flow to the tissues). When there is bald atrophic, sun damaged scalp, I generally perform two hair transplant sessions of lower density (in place of one) spaced at least a year apart to give time for the scalp to heal and blood flow to increase in the area.

I often have the patient treated with topical 5-flurouracil before the surgery to improve the quality of the skin and to treat or prevent pre-cancerous growths from the sun.

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Q: Is it possible to tell me roughly how many grafts would be left from donor area if one had a hair transplant of 2,500 grafts and had a density of around 2.0? G.H. – New York, NY

A: How much hair can be harvested in total depends upon a number of factors besides donor density. These include: scalp laxity, hair characteristics (such as hair shaft diameter, color and wave), and the actual dimensions of the permanent zone.

Every person is different, so all of these factors would need to be taken into account to determine the total number of grafts that would be available for the hair restoration.

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Q: What causes graft popping during a hair transplant? G.K. – Carle Place, N.Y.

A: Popping, or the tendency for grafts to elevate after they have been placed into the recipient area, is caused by a number of factors including:

  • Packing the grafts too closely, particularly when they are placed on a very acute (sharp) angle with the skin
  • Rough placing techniques
  • Bleeding
  • Poor fit between the graft and recipient site
  • Natural characteristics of the patient’s skin, including the elasticity and stickiness of wound edges

The problem with popping is that it exposes grafts to drying (while they are elevated on the skin surface) and trauma (when they have to be re-inserted).

The judgment and experience of the surgeon performing hair transplants is extremely important in minimizing popping. It is important that the surgeon customize the site size to the different size follicular unit grafts and to test the recipient sites as they are made, to make sure that the “fit” is perfect.

Although it is important to place grafts close together to get the best cosmetic result possible, over-packing of the grafts risks popping and other factors (such as overwhelming the blood supply) that may lead to poor growth.

In the end, maximum growth of the transplanted hair should be the primary goal.

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Q: I have had some surgical procedures on my head that left a fair amount of scar tissue. Can hair grow there? Is it a more difficult procedure? Are there any complications? – Darien, C.T.

A: Transplanted hair will grow in scar tissue as long as the tissue is not thickened. Thickened scar tissue can be flattened with local injections of cortisone.

Once the scar is smooth, the hair transplant procedure is relatively straightforward, however a few things must still be kept in mind.

  1. Since the blood supply of the scar tissue is less than in normal tissue, the grafts should not be placed as close.
  2. As the grafts from the hair transplant grow, new blood vessels are formed in the area.
  3. Additional density can then be achieved in a subsequent session by adding more grafts.
  4. After the hair restoration procedure, care must be taken with grafts transplanted into scar tissue, as the scarred scalp doesn’t hold onto grafts as well as normal tissue and they are more easily dislodged.

If grafts are packed too closely into scar tissue, poor growth can result. If sites are placed properly and the post-op care is diligent, good growth should be expected.

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Q: When a donor strip is taken out during a hair transplant and separated under the microscope, you can read on the internet that there is a wastage of grafts (about 15%), because of those unseen telogen hairs. What do you think about that and how does it affect the hair restoration? — T.B. Baldwin, New York

A: The Telogen phase of the hair cycle is about 3 months long and about 12% of follicles are in this phase at any one time. It is speculated that the follicles may be empty for perhaps 1/2 that time (this number may vary significantly between people). Therefore, approximately 6% of the hair follicles may be in telogen at any one time.

On average about 15% of the follicular units are 1-hair units (but this also may very greatly between patients). If 6% of all follicles are “empty” telogen follicles, then there should be .15 x .06 = .009 or about 1% of the patient’s 1-hair follicular units in the empty telogen phase that can’t be identified and will be missed on dissection.

The 1% isn’t very large. However, also consider that the remaining 5% of the empty follicles are associated with larger follicular units (i.e. those with 2-4 hairs). If these follicular unit grafts are closely trimmed, as is the practice with very dense packing, a much more significant number of follicles are at risk of being lost. With chubby follicular unit grafts (i.e., where the microscopic dissection leaves a protective sheath of tissue around the follicles) the risk should be closer to the 1%.

The lesson for hair transplantation is that over-trimming of grafts, for the sake of very dense packing, may waste telogen hairs as well as place the grafts at an unnecessary risk of mechanical trauma, drying and warming.

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Q: Does dense packing hurt grafts? — P.L., Rye, NY

A: There is no absolute answer to this question. In a hair transplant, dense packing of grafts has a risk of decreasing yield if there is a significant amount of photo damage to the scalp (which alters the blood supply) and if there is a tendency for the grafts to pop (this is difficult to predict pre-operatively). Very closely spaced grafts exacerbate the popping and expose the grafts to desiccation (drying), hypoxia (lack of oxygen) and mechanical trauma from the necessary re-insertion.

That said, the skill of the hair transplant surgeon and placing team, the size of the recipient sites, and the way the grafts are dissected and trimmed all play important roles in determining graft survival in dense packing.

Read a thorough analysis of the “pros” and “cons” of large hair transplant sessions
Read answers to more questions on dense packing of grafts

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