THE SCIENCE OF FUE

 

Follicular Unit Extraction (FUE), whether manually or through robotics, is performed with a precise science. Calculation of the angle of the hair is one of the most important considerations in removal of hair via Follicular unit extraction.  A follicular unit is a group of hairs growing together and comprising a hair graft. These clusters of hairs are removed together and the surgeon attempts to avoid transecting or cutting the graft along its root.  Cutting the graft will essentially lead to a nonviable graft. The analogy here is cutting a tree via its trunk and trying to plant it. The hair needs the root system and the branches.

The exit hair angle of the hair can be calculated by astute surgeons.  

Typically the exit angle of the hair is different than the angle of the hair within the scalp.  The challenge is that the human eye must make some calculations to properly remove hair without transecting it:

  1. Exit angle
  2. Anticipated hair within scalp
  3. Caliber of the hair (size of the hair)
  4. Amount of hairs in graft (1,2,3,4)
  5. Shape of the hair
  6. Depth of the hair- too shallow will lead to transection of hair or capping of the graft, too deep will lead to excess tissue removal
  7. Alterations in tissue angle with injections of saline or lidocaine – angles will become more perpendicular to skin
  8. Friction created by the punch due to rotational forces- each punch rotates into the skin which can alter the entry angle into the skin and alter the position of the hair shaft.
  9. Change in pattern of hair once in contact with the extraction device (FUE)

The challenge is that this calculation must be done on each hair removed from the head.  

Some methods of extraction will utilize larger punches to help give more leeway around the hair.  Larger punches can lead to larger holes which can cause the following potential issues:

  1. Higher rate of hyperpigmentation
  2. Longer heal time- skin repairs itself in a milli-metric process daily

 

Besides the challenges in calculations of removing the hair, visualization and physical removal process is necessary.

Visualization can take place with magnification via human eyes. However, the human eye can have difficulty detecting variance in pattern, angle, seeing the pattern below the scalp.  The human eye is also variable from person to person with some FUE surgeons with good vision and others with potentially poor vision.

The physical challenge of removal of hair is to incorporate all of the above data and then to be able to remove it without transecting the hair. To do so all of the following must be accomplished:

  1. Hand must be able to hold the FUE device at a steady angle at approach and while bringing the apparatus closer to the head.  Once the device strikes the skin, the hand must be able to make a microadjustment to change angle below skin. For example, for a hair with an exit angle of 23 degrees, the internal angle may be 21 degrees and the hand must adjust accordingly or the hair will be transected.
  2. Resist the rotational force of the spinning FUE device.  Not only must the hand be held steady, it must be held steady enough to within stand the spinning along the contact point.  
  3. Stop at exactly the depth of the hair shaft to allow enough hair to be incorporated into the hair graft

 

If all of these above criteria are met, the FUE surgeon has removed only one hair graft and this must be repeated typically 1000-3000 times with as much precision.

 In addition, the human eye must also only pick out the best hairs in anagen phase (telogen hairs will not grow) as well as take out hairs in an irregular pattern so that the hair donor site is inconspicuous.  (link to hair loss pattern blog) In our experience, the transection rate is MUCH higher with handheld FUE for all of these reasons and the added comment that humans tire. Hands hurt (injuries are rampant from FUE- google it), wrists hurt, eyes get tired.  

In fact, if you wanted to test this attempt to thread a hair with the eye of the needle.  

Now imagine doing this with a longer needle and one which weighed 2-3 pounds and that if you touched the hair, the hair was transected.  It is not easy for a regular human. In fact, it is almost impossible for ANY human to do once, let alone repeatedly.

The benefits of robotic removal are many and include the following:

  1. Artificial intelligence built into system- The system is constantly updated and with each software update the robot removes hair and adjusts with every ARTAS user in the world to make the process more efficient, faster, and more precise
  2. Can detect hairs, hair angle, calculate entry angles, exit angle, hair length, number of hairs on each graft
  3. Can hold the extraction angle steady and micro-adjust at internal skin
  4. Can adjust to depth of removal for each hair
  5. Can remove hairs in an irregular pattern
  6. Can resist rotational forces and incorporate those forces into removal of the hair
  7. Can actually do real time adjustments if additional local or saline is injected into the hair
  8. Can detect optimal hairs for removal, scar tissue

 

Our transection rate at Aesthetic Scalp was around 50% which is what our practice suspects is the rate at almost every office with FUE.  

With Robotic removal, the transection rate in our office is typically less than 5%. In Dr. Shah’s procedure, he had 1000 graft attempts and 1 transected hair.  If you are going to have hair transplantation, have it with FUE.  If you are going to have FUE, make sure your extraction process is as exacting as possible, which translates to only one option in our opinion:  ARTAS.