What are the recommended settings for a CO2 (Carbon Dioxide) laser for Multi-Line Scan (MLS) treatments?

CO2 Laser Settings for Multi-Line Scan (MLS) Treatment

For optimal CO2 laser Multi-Line Scan (MLS) treatments, use low pulse repetition rates (10-60 Hz) with focused beam delivery achieving power density >60 kW/mm² to minimize thermal damage while maintaining effective tissue ablation.

Optimal CO2 Laser Parameters for MLS

Power and Energy Settings

• Pulse Duration: 1-2 microseconds (ultrashort pulses)
• Pulse Repetition Rate: 10-60 Hz (optimal range)
  • Lower rates (10-60 Hz) minimize thermal damage zone by 80% compared to higher rates 1
  • Rates above 200 Hz provide no additional ablation benefit 1
• Power Density: >60 kW/mm² when focused
• Energy Settings:
  • For facial treatments: 15 mJ with double pulse (equivalent to 30 mJ single pulse) 2
  • For body treatments: Lower settings than facial areas due to different tissue response

Scanning Pattern Configuration

• Density: 10% coverage for fractional treatments 2
• Scan Pattern: Multi-line configuration with appropriate spacing
• Treatment Area: Include 1 cm margin beyond visible lesion borders

Tissue-Specific Considerations

Facial Applications

• Double pulsing at lower energies (15 mJ) produces similar ablation depth to single pulsing at higher energies (30 mJ) 2
• Facial skin responds differently than body skin to the same settings
• Consider pulse stacking for consistent tissue contraction with lower energy settings 3

Body Applications

• Require different settings than facial treatments due to varying tissue thickness
• Abdominal treatments show significant differences in microthermal zone depth between single and double pulse modes 2

Technical Considerations

Thermal Damage Control

• Thermal damage can be minimized by:
  • Using ultrashort pulse durations (1-2 microseconds) 4
  • Maintaining lower pulse repetition rates 1
  • Proper focusing of the beam to achieve adequate power density 5
• Thermal damage zones can be reduced from 750 μm to as little as 50 μm by using shorter pulses 4

Treatment Efficacy

• For hidradenitis suppurativa treatments, CO2 laser has shown positive outcomes in multiple uncontrolled retrospective series for Hurley stage II or III disease 6
• Scanner-assisted CO2 laser treatment under topical anesthesia has shown only 1.1% recurrence in follow-up periods of 1-19 years 6

Clinical Applications

Hidradenitis Suppurativa

• CO2 lasers are used for excision, marsupialization, and vaporization of affected skin 6
• Patient satisfaction is high with 95% reporting improvement and 91% recommending the procedure 6
• Recurrence rates within treated areas range from 1.1% to 29% depending on technique 6

Bowen's Disease

• For lower leg lesions, caution is advised as there is 12% progression to invasive carcinoma within 12 months when depth is inadequate 6
• CO2 laser is recommended for erythroplasia of Queyrat with good results 6
• For digital lesions, retrospective reviews show good cosmetic results 6

Pitfalls and Caveats

• Inadequate depth of treatment may lead to recurrence or progression, particularly in Bowen's disease 6
• New lesions may develop adjacent to treated areas (35.3% of cases) despite successful treatment of the target site 6
• Flares in untreated areas occur in 73.5% of hidradenitis suppurativa patients 6
• Thermal damage increases significantly when pulse repetition rates exceed 60 Hz 1

By following these guidelines, clinicians can optimize CO2 laser MLS treatments to achieve effective tissue ablation while minimizing thermal damage to surrounding tissues.