Prior to revis­ing a scar, it is impor­tant to take a care­ful patient his­tory and find out specif­i­cally what, if any­thing went wrong with pre­vi­ous surg­eries. It is pre­sump­tu­ous to think that just because a patient has scar­ring, the next pro­ce­dure will make it bet­ter. One should care­fully review the sur­gi­cal his­tory and, if pos­si­ble, speak with the orig­i­nal sur­geon to see if there are any tech­niques that could be improved upon, or prob­lems that occurred which might be avoided in future pro­ce­dures.
The cause of an unac­cept­able scar may be due to poor heal­ing intrin­sic to the patient, such as the ten­dency to form keloids. It might also be caused by a genetic pre­dis­po­si­tion to poor heal­ing because of con­nec­tive tis­sue defects, such as Ehlers-Danlos Syn­drome. Genetic or drug induced coag­u­lopathies, or med­ica­tions that inter­fere with heal­ing can also result in unac­cept­able scars. In addi­tion, scar­ring may be caused by com­pli­ca­tions such as a post-operative infec­tion or sim­ply from the patient not fol­low­ing post-op instruc­tions, such as smok­ing or per­form­ing stren­u­ous exer­cise too soon after the surgery.
As empha­sized in the pre­ced­ing dis­cus­sion, a depleted donor sup­ply is the major lim­i­ta­tion to a suc­cess­ful repair. The inabil­ity to har­vest addi­tional hair is caused by two main fac­tors. The first fac­tor is the phys­i­cal limit set by the com­bi­na­tion of low donor den­sity and poor scalp mobil­ity. When donor den­sity is low, a larger strip must be har­vested to obtain an ade­quate amount of hair. A tight scalp, how­ever, lim­its the size of the strip that can be removed. After mul­ti­ple pro­ce­dures, attempt­ing to har­vest addi­tional hair is no longer worth the risk of a pos­si­ble widened scar. Every hair trans­plant pro­ce­dure simul­ta­ne­ously decreases donor den­sity and scalp lax­ity, but poorly exe­cuted surgery does this to a greater degree and decreases the sup­ply with­out mak­ing pro­por­tion­ate cos­metic improve­ments in the recip­i­ent scalp.
The sec­ond fac­tor is the vis­i­bil­ity of the donor scars. Once the donor scars are to the point of near vis­i­bil­ity, the abil­ity to har­vest addi­tional hair is severely lim­ited, as fur­ther surgery would make the patient’s pre­vi­ous trans­plant surgery appar­ent. An impor­tant point to keep in mind in judg­ing how much addi­tional hair is avail­able, is that cov­er­age of donor scar­ring is more closely related to the amount of donor hair present than to the degree of scar­ring. There­fore, any process that removes hair along with the scar will run the risk of mak­ing the donor scar­ring more vis­i­ble. The rea­son is that when scar and hair are both removed, the clo­sure will fur­ther stretch the scalp and decrease the den­sity of the remain­ing hair. This may pre­vent it from cov­er­ing other scars that have not been excised or thin out the appear­ance of the donor fringe to an unac­cept­able degree.
Tech­niques, such as Fol­lic­u­lar Unit Extrac­tion, where fol­lic­u­lar units are har­vested directly from the donor area with­out a lin­ear exci­sion can be use­ful when the scalp is very tight. The use­ful­ness of this tech­nique is lim­ited, how­ever, as sig­nif­i­cant donor scar­ring makes remov­ing hair with­out tran­sec­tion dif­fi­cult and a donor zone of low den­sity lim­its the amount of hair that can be removed with­out the area becom­ing too transparent.

Fol­lic­u­lar unit extrac­tion is a method used to har­vest grafts in the least inva­sive way.  Fol­lic­u­lar unit extrac­tion enables the sur­geon to extract hair fol­li­cles using a tiny punch, with­out the need to remove a strip of hair bar­ing skin. This method of har­vest­ing hair fol­li­cles is what makes FUE dif­fer­ent from the stan­dard hair restora­tion pro­ce­dure. In the typ­i­cal sur­gi­cal hair restora­tion pro­ce­dure a strip of skin con­tain­ing bald resis­tance fol­li­cles is removed, this strip is then dis­sected care­fully under mag­ni­fi­ca­tion to pro­duce indi­vid­ual hair grafts. Both the extrac­tion and the strip exci­sion pro­ce­dure pro­duce com­pa­ra­ble micro grafts. The major dif­fer­ence between the two meth­ods is the har­vest­ing of the grafts.

The Pros and Cons of Fol­lic­u­lar Unit Extraction

Pros

·         Fol­lic­u­lar unit extrac­tion is the min­i­mally inva­sive way which fol­lic­u­lar unit grafts are removed.

·         There is less trauma to the graft dur­ing the extrac­tion process then with the tra­di­tional method

·         Patients who have reduced donor den­si­ties, due to poor hair qual­ity in the donor area, have a bet­ter, health­ier selec­tion of grafts.

·         Patients with tight scalps, where tra­di­tional strip har­vest­ing can be prob­lem­atic, are able to receive hair restora­tion now that this method is being used.

·         There is no vis­i­ble scar, patients who like to keep a short hair cut would ben­e­fit from this

Cons

·         The max­i­mum amount of grafts can­not be harvested

·         Grafts har­vested from places other than the donor area will not be permanent

·         The cost is twice as much as the tra­di­tional procedure

·         Prob­lems of “cap­ping” (this is when the top of the graft pulls off dur­ing the extraction)

·         Mul­ti­ple ses­sions are required to equal one strip method procedure

·         Patients with curly or fine hair are gen­er­ally not good can­di­dates for FUE