Manual tools for FUE – BOLA analysis, presentation Dr. Chueco

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Dr.Alejandro Chueco (http://www.injertocapilar.com.ar/) presented an interesting talk during the 2nd International Wold FUE Institute Workshop regarding hand tools used for FUE extraction.

The first important definition is that of the punch (punch in Italian), which is nothing more than a metal cannula designed to cut the structures that keep the follicular unit anchored to the surrounding tissue.

The punch is the most common tool and is found in all variations of the FUE technique.

The punches are made of stainless steel to avoid possible chemical reactions when they come in contact with the scalp.

The most commonly used punches are those made of 300 series stainless steel. To preserve their sharpness they are often coated with titanium nitride (small gold-colored tip that can be seen in some punches).

Only Cole Instruments’ punch is made from 400-series steel (stronger and sharper).

Punches for manual extraction of follicular units can be classified using several discriminants:

1 – Outer diameter punch (with inside bevel): This is a punch in which the sharp edges of the bevel are on the outer surface of the walls of the punch (inside bevel)

2 – Medium-diameter punch (with center bevel): This is a punch in which the cutting edges of the bevel are in the center of the walls of the same (middle bevel)

3 – Inside diameter punch (with outside bevel): This punch has the sharp edges of the bevel along the inside face (outside bevel)

Classification of punches according to the diameter of the cutting edge (cutting edge)

1 – Small punch: has a cutting edge diameter (distance between the cutting edges of the punch) less than or equal to 0.8 millimeters

2 – Medium punch: has a cutting edge diameter (distance between the cutting edges of the punch) greater than 0.8 millimeters and less than 1 millimeter

3 – Large punch: has a cutting edge diameter (distance between the cutting edges of the punch) greater than 1 millimeter

 

Benefits of a large punch:

  • More hair per follicular unit extracted
  • Follicular units have a greater amount of connective tissue
  • Lower transection rates (unit damage)

Benefits of a small punch:

  • Less risk of hypopigmentation (white dots)
  • Less trauma to follicular units
  • Less distortion to the follicles surrounding the one extracted
  • Possibility of “in situ” splitting (i.e., possibility of separating multiple follicular units into doubles or singles)
  • More incisions per cm2 in recipient area

Disadvantages of a large punch:

  • More risk of hypopigmentation (white dots)
  • More distortion during extraction of the follicles surrounding the one extracted
  • More trauma in donor area

Disadvantages of a small punch:

  • More transection rates
  • Follicular units with less tissue and therefore more fragile

 

Dr.Chueco next addressed the concept of damage in FUE:

When the punch cuts the skin and the follicular unit is extracted, the result is a circular “hole” whose diameter is the only real value to be considered for measuring the punch.

The diameter of the circular hole left in the skin is directly related to:

  • Diameter of the cutting edge (cutting edge) of the punch
  • Outer walls of the punch the which at its times produce damage related to rotational friction and by the expansion forces exerted on the surrounding tissue

In the photo below we can see the outcomes in donor area of extraction with Artas vs 0.8 mm punch

 

The punch produces a circular scar whose area can be calculated by multiplying pi x the radius squared (π x r2 ). This is the damage caused by FUE extraction.

It should be mentioned that in power punches it is particularly complex to make a straight cut and thus maintain a perfect circle because of the oscillation of the machine. The greater the oscillation the greater the hole created and thus the damage created in the donor area.

The depth of the extraction is another key factor, one should never go beyond the limit of the erector pili muscle. In the picture below extracting at a depth corresponding to point 1 or 3 is an error while extraction should be done at point 2.

 

The patient’s healing will depend on:

Type of cut made and type of skin of the patient

Actual area that sustained the damage of the extraction

Depth of the extraction, the deeper the slower and more problematic the healing.

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