# Principles of Scar Management and Revision
## Overview
Scar formation is the inevitable outcome of wound healing that extends beyond the superficial epidermis. Understanding the pathophysiology of abnormal scarring, the timing of intervention, and the range of available therapies is critical for plastic surgeons. Scar revision is not about eliminating scars -- it is about converting a conspicuous scar into one that is less noticeable and more functionally acceptable.
## Normal Scar Maturation
Scars undergo remodeling for 12-18 months after injury. Initial phase: erythematous, raised, firm, pruritic. Mature phase: pale, soft, flat, non-tender. Collagen is reorganized from type III (immature) to type I (mature) during remodeling.
Maximum tensile strength: approximately 80% of unwounded skin (never returns to 100%). Scar revision should generally wait until full maturation (12-18 months) unless functional impairment demands earlier intervention.
## Hypertrophic Scars vs. Keloids
### Hypertrophic Scars
Remain within the boundaries of the original wound. Develop within weeks of injury. Often related to excessive wound tension, infection, or prolonged healing. Frequently occur across joints, upper trunk, and shoulders.
May regress spontaneously over 1-2 years. Histology: organized collagen bundles parallel to the epidermis, nodules of myofibroblasts.
### Keloids
Extend beyond the boundaries of the original wound into normal tissue. May develop months to years after injury. Genetic predisposition: higher incidence in individuals with darker skin pigmentation (African, Asian, Hispanic descent). Common locations: earlobes, sternum, deltoid, upper back.
Rare below the knee or on the eyelids, genitalia, palms, and soles. Do NOT regress spontaneously. High recurrence rate after excision alone (50-80%). Histology: thick, disorganized, hyalinized collagen bundles ("keloidal collagen"), no nodular pattern.
### Key Differentiating Features
| Feature | Hypertrophic Scar | Keloid |
|---------|-------------------|--------|
| Extends beyond wound | No | Yes |
| Spontaneous regression | Yes (often) | No |
| Genetic predisposition | Less prominent | Strong |
| Response to excision alone | Good | Poor (high recurrence) | | Histology | Organized collagen | Hyalinized collagen |
## Non-Surgical Scar Management
### Silicone-Based Therapy
Silicone gel sheeting and topical silicone gel are first-line for prevention and treatment. Mechanism: hydration of stratum corneum, modulation of fibroblast activity, reduced transepidermal water loss. Should be worn 12-24 hours/day for a minimum of 3 months. Evidence: Grade B recommendation from international consensus panels.
### Pressure Therapy
Custom pressure garments (25-30 mmHg) for burn scars. Mechanism: ischemia-induced collagen remodeling, reduced fibroblast activity. Most effective when applied early and continuously (23 hours/day). Duration: 6-12 months or until scar maturation. Primarily used for burn patients; less practical for small surgical scars.
### Intralesional Corticosteroid Injection
**Triamcinolone acetonide (TAC)** -- most commonly used. Concentration: 10-40 mg/mL (10 mg/mL for hypertrophic scars; 40 mg/mL for keloids). Mechanism: anti-inflammatory, inhibition of collagen synthesis, enhanced collagenase activity. Inject into the scar (not beneath it); multiple sessions at 4-6 week intervals.
Side effects: skin atrophy, telangiectasia, hypopigmentation, pain at injection. Most effective when combined with excision (intralesional injection immediately post-excision for keloids).
### 5-Fluorouracil (5-FU)
Antimetabolite that inhibits fibroblast proliferation. Concentration: 50 mg/mL, injected intralesionally. Often combined with TAC (reduces steroid side effects while maintaining efficacy). Regimen: weekly injections for 8-12 weeks.
### Other Medical Therapies
**Bleomycin** -- intralesional injection; cytotoxic to fibroblasts. **Verapamil** -- calcium channel blocker; reduces collagen synthesis. **Imiquimod 5% cream** -- immunomodulator applied post-excision to prevent keloid recurrence. **Botulinum toxin** -- reduces wound tension by paralyzing underlying muscles; may improve scar quality in facial wounds.
## Laser Therapy
### Pulsed Dye Laser (PDL) -- 585/595 nm
Targets oxyhemoglobin in scar vasculature. Reduces erythema, height, and pliability of hypertrophic scars and keloids. Multiple treatments required (3-6 sessions at 4-8 week intervals). Best evidence for hypertrophic scars; adjunct for keloids.
### Fractional CO2 Laser
Creates microscopic columns of thermal injury that stimulate remodeling. Improves texture, pliability, and height of both hypertrophic and atrophic scars. Can be combined with topical drug delivery (laser-assisted drug delivery of TAC or 5-FU).
### Nd:YAG Laser
Deeper penetration; targets deeper dermal collagen. Used for thicker, more established scars.
## Radiation Therapy
Adjunct to surgical excision for recalcitrant keloids. Administered within 24-48 hours of excision. Total dose: 12-20 Gy in 3-5 fractions (superficial X-ray or electron beam). Reduces keloid recurrence to 10-20% (compared to 50-80% with excision alone).
Concerns about theoretical malignancy risk -- generally reserved for adults and non-breast locations. Controversial but effective for severe, multiply recurrent keloids.
## Surgical Scar Revision Techniques
### Timing
Wait 12-18 months for scar maturation before elective revision. Exceptions: functional contractures, significant distortion of anatomical landmarks. Rule: "Don't revise a scar unless you can make it better".
### Fusiform (Elliptical) Excision
Standard excision and re-closure with meticulous technique. 3:1 to 4:1 length-to-width ratio to avoid dog ears. Reorient the scar to align with RSTLs if possible. Layered closure with deep dermal sutures to minimize tension.
### Z-Plasty
Redirects scar to align with RSTLs. Lengthens contractures (60-degree angles provide 75% lengthening). Breaks up scar linearity. Multiple small Z-plasties (serial/running Z-plasty) for long scars.
### W-Plasty
Breaks up linear scar into irregular zigzag pattern. Does not change scar direction or length. Useful when scar cannot be redirected with Z-plasty.
### Geometric Broken Line Closure (GBLC)
Random geometric shapes (triangles, rectangles, semicircles) interdigitated along both sides of the scar. Creates maximum irregularity to camouflage the scar. Technically demanding but provides excellent results for long, straight scars on the face.
### Tissue Rearrangement
Local flaps (advancement, rotation, transposition) to redistribute tension. Particularly useful when scar is wide due to tension across the wound.
### Serial Excision
Staged excision of large scars or lesions that are too wide for single-stage closure. Each stage removes a portion of the scar/lesion. Tissue relaxation between stages allows progressive closure.
## Dermabrasion and Microneedling
**Dermabrasion** -- mechanical resurfacing that blends scar edges with surrounding skin. Performed at 6-8 weeks post-injury or revision (during the "window of collagen remodeling"). **Microneedling** -- percutaneous collagen induction; creates micro-channels that stimulate remodeling. Useful for atrophic and acne scars; less effective for hypertrophic scars.
Comparative histological illustration showing cross-sections of three types of scars: (A) mature normal scar with organized parallel collagen fibers and flat surface, (B) hypertrophic scar with nodular collagen bundles containing myofibroblasts, raised surface that remains within original wound borders, and (C) keloid with thick hyalinized disorganized collagen extending beyond the original wound borders into normal tissue. Epidermis, dermis, and subcutaneous tissue layers labeled. Clean medical illustration style with collagen fibers depicted in distinct patterns for each scar type.
Illustration demonstrating geometric broken line closure (GBLC) technique: (A) long linear scar on the face, (B) design of random geometric shapes (triangles, semicircles, small rectangles) along each side of the scar creating interdigitating patterns, (C) excision of the scar with the geometric pattern, (D) closure with precise alignment of the geometric elements producing an irregular, well-camouflaged scar line. Top-down surgical planning view in medical illustration style.
## Key Clinical Pearls
Never revise a scar before it is mature (12-18 months) unless there is a functional indication -- many scars improve dramatically during natural remodeling. Keloids extend beyond the wound boundaries and do NOT regress spontaneously; hypertrophic scars stay within the wound and often regress over 1-2 years. Excision alone for keloids has a 50-80% recurrence rate -- always combine with adjuvant therapy (steroid injection, radiation, or 5-FU). Silicone gel sheeting is the best-supported non-surgical therapy for both prevention and treatment of hypertrophic scars and keloids.
Intralesional triamcinolone (10-40 mg/mL) is the first-line injection therapy; combine with 5-FU to reduce steroid side effects. Radiation therapy within 24-48 hours of keloid excision reduces recurrence to 10-20% and is the most effective adjuvant for recalcitrant keloids. The goal of scar revision is never scar elimination -- it is conversion to a less conspicuous scar. Z-plasty is the most versatile scar revision technique: it redirects, lengthens, and breaks up linearity simultaneously.
## References
- Mustoe TA, Cooter RD, Gold MH, et al. International clinical recommendations on scar management. *Plast Reconstr Surg*. 2002;110(2):560-571.
- Ogawa R. Keloid and hypertrophic scars are the result of chronic inflammation in the reticular dermis. *Int J Mol Sci*. 2017;18(3):606.
- Berman B, Maderal A, Raphael B. Keloids and hypertrophic scars: pathophysiology, classification, and treatment. *Dermatol Surg*. 2017;43(Suppl 1):S3-S18.
- Borges AF. Scar revision and camouflage. In: *Elective Incisions and Scar Revision*. Little, Brown; 1973.
- Gupta S, Kalra A. Efficacy and safety of intralesional 5-fluorouracil in the treatment of keloids. *Dermatology*. 2002;204(2):130-132.