Definition
Scar revision is unique in the field of facial plastic and reconstructive surgery because the initial traumatic event and its immediate treatment is  not  within the control of the plastic surgeon . Candidates for scar revision procedures often present after significant loss of regional tissue, injury that crosses anatomically distinct facial aesthetic units ,  inadequate  wound closure  and  poor post -injury wound management.

Etiology
Unfavorable facial scars result from a variety of influences, over which the reconstructive surgeon often has little initial control. Patients who present with unaesthetic facial scars typically have wounds that (1) exhibit an unfavorable configuration with respect to length and direction of RSTLs ( relaxed skin tension lines), (2) have undergone pathologic healing processes,  (3) unfavorably cross anatomic regions, (4) are subjected to constant deforming contractile forces because of underlying anatomy, and (5) are deeply traumatic.

Purpose
Psychological and physical considerations

• Patients who have been injured frequently bear psychological trauma  which  often persists irrespective of the time between injury and surgical consultation.
• It may be in the best interests of both surgeon and patient to seek adjunctive consultation with a therapist well versed in the treatment of posttraumatic stress disorder (PTSD) for patients whose scar revision follows significant psychological trauma.
• The  waiting period for scar revision also  allows the patient sufficient time to adjust psychologically to the prospect of undergoing another facial surgical procedure and to make a more dispassionate consideration of the surgeon's treatment plan.
• Patients are required to have a  realistic perspective of the lengthy healing time following revision procedures, likely outcomes given the injury characteristics, and the possibility of future adjunctive procedures such as dermabrasion, laser resurfacing, or multiple steroid injections.

Preparation

Timing of scar revision

Timing of scar revision depends on type and location of injury and the psychological readiness of the patient. A  6- to 12-month waiting period following initial injury is usually advised . Before the surgical intervention , a thorough assessment includes characteristics of the initial injury, relationships to anatomic location and relaxed skin tension lines (RSTLs), likelihood of pathologic healing (such as  hypertrophic scar , keloid ) ,  and any regional functional impairment by deformity ( such as  oral or ocular impairment ) . Surgeons should also recognize that conservative nonsurgical methods may be applicable as a primary treatment method.

Description

The following will present the most common surgical techniques in scar revision :
 
Z-plasty
As a transposition flap, Z-plasty allows for 2 adjacent undermined triangular flaps, constructed from the same central axis, to transpose over each other and to lie in the other's originating bed.
 


Scar revision. Classic Z-plasty composed of two 60° angles.


W-plasty

W-plasty (also termed the running W-plasty or zig-zag plasty) is in rendering a lengthy linear scar irregular.



Scar revision. Size and number differential between W-plasty triangles to ensure corresponding fit between inner and outer wound curvature.


Geometric broken line closure

A variant of the W-plasty, geometric broken line closure (GBLC) employs the same illusory principles as a W-plasty, seeking to maximally create irregularity in a linear scar and thus render it less visible than a procedure with a regular patterned unbroken configuration.

Scar revision. Excision following design of geometric broken line.

M-plasty

A useful technique to preserve healthy tissue and lessen the chance of secondary tissue deformity is the M-plasty. The M-plasty, by creating 2 separate 30° angles instead of one, decreases the loss of surrounding healthy tissue by nearly 50%.

Scar revision. Central scar with bilateral M-plasty.

Adjunctive Techniques

Dermabrasion

• Dermabrasion works  by superficially abrading  the scar and the surrounding skin in a precise and controlled manner  which results in a smoother  texture .
• The process  improves the appearance of uneven scar edges and raised grafts and flaps by leveling the irregular contours.  
• The best candidates for  dermabrasion are those with lighter complexions, because the risk of  postabrasion  dyspigmentation   is lowest in these patients.

Laser resurfacing Techniques

Ablative vs Non-ablative Lasers

• Pulsed ablative lasers (such as carbon dioxide and erbium: YAG) can provide similar results as dermabrasion by superficially ablating the scar. Each laser has its distinct advantages.
  • Erbium:YAG, is more precise in ablating raised scar edges  due to  its higher affinity for water.
  • The carbon dioxide laser causes more thermal necrosis  leading to wound contraction and collagen remodeling.
• All ablative procedures (  lasers and dermabrasion ) may result in pigmentary alteration and carry the risk of worsening a scar from overaggressive treatment.
• Nonablative lasers have the advantage of improving scars without incision or wounding  decreasing downtime. These lasers  works through heating collagen thereby improving the appearance of  a scar.
  • The flashlamp-pumped pulsed dye laser has renders its effect  through absorption by oxyhemoglobin, causing direct destruction of the blood vessels and an indirect effect on the surrounding collagen.
  • Improvement in the the overall redness caused by the scar's vascularity and promotes collagen remodeling and scar softening . An effect best suited for red hypertrophic scars or for telangiectases surrounding scars, which typically are not noticed for at least 1 month postoperatively.
  • Newer nonablative lasers with wavelengths of 532 nm, 1064 nm, 1390 nm, and 1450 nm are also being used to promote collagen remodeling

Intralesional Steroids

• Hypertrophic linear scars, bulky grafts and flaps, can be treated with intralesional corticosteroids. Injections can be instituted at approximately 1 month postoperatively.
• A small amount (as little as 0.1 mL) of low-dose triamcinolone acetonide  at 5 to 10 mg/mL is injected into the scar; this dosage can be repeated monthly until the scar has flattened.
• Side effects include atrophy (  if the injection leaks out into healthy skin ),  hypopigmentation and telangiectasias when injected in higher concentrations into the dermis.

Contraindications

Contraindications to scar revision include :

• Patient is not psychologically prepared which limits a favorable visible outcome
• Unrealistic expectations of what the revision procedure is capable of providing.
• Candidates with history of hypertrophic or keloid scarring are at higher risk of a poor aesthetic result and  must be weighed against the expectation of a cosmetically superior revision.
• Poor candidates are those  with traumatically thickened or discolored skin because the less compliant skin ultimately may compromise the revised scar.