648 Direct Comparison of Fractional Carbon Dioxide Lasers Systems: Ablative Well Properties and Healing
Bibliographic record
Abstract
Abstract Introduction Ablative lasers are a common tool for burn scar remodeling with numerous commercially available systems, each with varying capabilities. Among fractional CO2 (FXCO2) laser systems, the same nomenclature is utilized to describe properties of the laser including beam fluence and fractional coverage. Despite identical laser settings for these properties, the outcomes in two patient cohorts utilizing two different FXCO2 laser systems were notably different. As a result, a direct comparison of ablative wells, fractional coverage and healing between the two systems was conducted using ex-vivo and porcine models. Methods An ex-vivo study comparing fractional coverage settings (1%, 3%, and 5%) between the two different FXCO2 laser systems was first carried out (all measurements were obtained by a blinded rater using a high-powered microscope to quantify ablative area). Porcine skin was then treated with the two systems at 10–70 mJ. To compare ablative well properties, biopsies were collected and serial sectioned with the deepest/widest point of each well calculated from the histological section using ImageJ. Fractional coverage for each laser system was quantified for three different settings: 70 mJ 1%, 70 mJ 5%, and 30 mJ 5%. Finally, re-epithelialization rate (as measured by transepidermal water loss), erythema and expression of genes encoding inflammatory cytokines were quantified in a porcine burn model prior to and at multiple time points following treatment with both laser systems (70 mJ, 5% fractional coverage). Results The two laser systems produced significantly different ablative wells. In the ex-vivo study, the fractional coverage measurements obtained differed from those provided by the manufacturer by 1.6 - 8.9%. In the porcine study, at 70 mJ, the ablative wells created from system 1 were deep and narrow, on average 1251 + 183 µm deep and 142 + 32 µm wide whereas wells from system 2 were shallow and wide, 374 + 44 µm deep and 267 + 35 µm wide. Following treatment, scars treated with system 2 re-established barrier function within 7 days whereas scars treated with system 1 re-established within 4 days. A significant increase in gene expression for IL-6 was observed in both systems at 1-hour post laser. Expression levels returned to baseline in system 2 by 24 hours whereas a return to baseline was not observed until the 96-hour time point for system 2. Conclusions While different FXCO2 laser systems utilize the same nomenclature for user selected properties, the same settings are not equivalent between systems resulting in significantly different ablative wells and downstream healing. Applicability of Research to Practice Laser systems should not be considered interchangeable despite being programmed for the same settings.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".