Aesthetic Dermatology MCQ - Fractionated non-ablative laser

A 45-year-old woman with Fitzpatrick skin type III seeks treatment for mild to moderate photodamage and early perioral rhytides. She desires minimal downtime and is willing to accept gradual improvement over multiple sessions. Which of the following devices creates microscopic columns of thermal injury in the dermis while leaving the epidermis intact, and what is its most common immediate postoperative appearance?

A) Fractionated non-ablative laser; erythema and edema
B) Ablative carbon dioxide (CO2) laser; erythema, edema, and serous exudate
C) Erbium:YAG (Er:YAG) laser; mild erythema with minimal exudate
D) Intense pulsed light (IPL); erythema and mild crusting
E) Pulsed dye laser; purpura

Correct Answer: A) Fractionated non-ablative laser; erythema and edema

Explanation

This question addresses the use of fractionated non-ablative lasers for skin rejuvenation, which are ideal for patients seeking minimal downtime.

Key Features of Fractionated Non-Ablative Lasers:

• Mechanism: These lasers (e.g., 1550 nm erbium-doped fiber laser) deliver microscopic columns of thermal energy to the dermis, creating microthermal zones (MTZs) of injury. The epidermis remains intact due to sparing of the surrounding tissue, which facilitates rapid healing.

• Indications: Mild to moderate photodamage, fine rhytides, dyspigmentation, and acne scars.

• Postoperative Course: The immediate appearance is erythema and edema (resembling a sunburn), which typically resolves within 24-48 hours. There is no exudate or crusting because the epidermis is not ablated.

• Treatment Protocol: Requires multiple sessions (typically 3-5) for gradual improvement, as collagen remodeling occurs over months.

Why This is the Best Choice for This Patient:

The patient desires minimal downtime and has mild to moderate photodamage, making a fractionated non-ablative device the optimal choice. It balances efficacy with a favorable recovery profile.

Why Not the Other Options?

• (B) Ablative CO2 laser: Provides significant dermal remodeling but causes erythema, edema, and serous exudate with a recovery time of 7-10 days. It is overkill for mild photodamage and contradicts the patient's desire for minimal downtime.

• (C) Er:YAG laser: An ablative laser that causes mild erythema with minimal exudate compared to CO2, but still requires 5-7 days of recovery. It is not fractionated non-ablative.

• (D) Intense pulsed light (IPL): A broadband light source used for dyspigmentation and erythema, but it does not create fractional columns of injury. Post-treatment, there is erythema and potential crusting of pigmented lesions.

• (E) Pulsed dye laser: Targets hemoglobin and causes purpura post-treatment. It is used for vascular lesions, not skin resurfacing for rhytides.

Management Considerations:

• Preoperative: Sun avoidance, topical priming with retinoids or hydroquinone (for pigmented skin types).

• Postoperative: Soothing skincare, sun protection, and scheduling of multiple sessions.

Prognosis:
Gradual improvement over months with low risk of dyspigmentation or scarring in Fitzpatrick types I-III.

Note: Fractionated non-ablative lasers are a cornerstone of "lunchtime" procedures due to their minimal downtime. The key is the creation of MTZs with intact epidermis, leading to dermal remodeling without ablation. Always align the device with patient goals (downtime tolerance) and clinical findings (severity of photodamage).