Liu J. et al. - Near-Infrared Light and Surgical Wound Healing: A Systematic Review and Meta-Analysis

Based on 56 clinical trials involving nearly 4,900 patients, near-infrared light applied after surgery is associated with improved healing and reduced postoperative pain. The overall certainty of the evidence remains very low.

What this study measured

Near-infrared light devices are increasingly being used after surgery, but the results of clinical trials remain inconsistent. This systematic review with meta-analysis, registered on PROSPERO under number CRD420251163415, compared near-infrared light (630 to 1,100 nanometers) to standard care or a placebo for surgical wounds. Fifty-six trials involving a total of 4,920 participants were included in the review, and 35 of these provided 69 usable results for the meta-analysis. The authors used a random-effects multilevel model, expressed as standardized mean differences (SMD). Additional analyses examined which parameters influenced the outcome: wavelength, fluence, number of sessions, application technique, and anatomical site. The risk of bias was assessed using Cochrane RoB 2.0, and the certainty of the evidence was assessed using GRADE.

Key Findings

Two criteria stand out as positive; the others remain inconclusive. The authors speak of a promise yet to be confirmed rather than a proven finding.

• Cicatrisation des plaies : SMD 0,78 (IC 95 % 0,46 à 1,09 ; p < 0,01) en faveur du proche infrarouge
• Douleur postopératoire : SMD 0,71 (IC 95 % 0,24 à 1,17 ; p < 0,01)
• Edema, scar appearance, and inflammatory markers: inconsistent results
• Best results are achieved at wavelengths ranging from 700 to 850 nanometers, with 4 to 10 sessions, using a non-contact application method
• High heterogeneity among studies and very low overall certainty of the evidence

The fact that edema, scar quality, and inflammatory markers do not change in a consistent manner is a warning sign that should not be ignored: the observed effect cannot yet be explained by a clear biological mechanism.

How photobiomodulation works for this indication

The proposed mechanism has not been verified here and is stated in the conditional tense. Near-infrared light penetrates a few millimeters into tissue and is thought to be absorbed by cytochrome c oxidase, the final link in the mitochondrial respiratory chain. This absorption is thought to increase ATP synthesis and alter the levels of reactive oxygen species, thereby modulating oxidative stress and inflammation. In a surgical wound, these signals are believed to promote fibroblast proliferation, collagen synthesis, and angiogenesis—that is, the formation of new capillaries that supply the healing tissue.

Limits You Should Know

The main limitation is clear: the overall certainty of the evidence is very low. There is high heterogeneity among trials, and the effects vary widely, which means that a given patient may not experience any benefit. The 56 trials cover a wide range of surgeries, sites, and protocols, and only 35 were included in the pooled analysis. Finally, secondary outcomes such as edema and scar appearance do not show a consistent trend, even though these are often the outcomes of greatest interest to patients.

What This Means in Practice

This is the first review of this scope on the subject, and it provides guidelines for treatment parameters. The best results are associated with wavelengths ranging from 700 to 850 nanometers, a series of 4 to 10 sessions, and noncontact application. These guidelines are based on exploratory analyses and do not constitute a validated protocol. A surgical wound remains the responsibility of the surgical team, and no light should be applied to a recent scar without their approval.

Frequently Asked Questions

Does infrared light speed up healing after surgery?

In this meta-analysis of 56 trials, it is associated with improved healing of surgical wounds, with an effect size of 0.78. This result is statistically significant but is based on evidence of very low certainty and highly heterogeneous trials. It does not guarantee an individual benefit.

What wavelength should be used for a scar?

The analyses in this review associate the best results with wavelengths ranging from 700 to 850 nanometers, over 4 to 10 sessions, using a non-contact method. These are trends identified retrospectively, not an established clinical recommendation.

Does near-infrared light reduce pain after surgery?

The authors report a reduction in postoperative pain, with an effect size of 0.71 (95% CI 0.24 to 1.17). The confidence interval is wide, indicating significant uncertainty regarding the actual magnitude of the benefit. This approach is not a substitute for prescribed pain medications.

Reference

Liu J, et al. Effects of Near-Infrared Light on Surgical Wound Healing: A Systematic Review and Meta-Analysis. International Wound Journal, 2026. PMID 41605843. View the study on PubMed

This summary is provided for informational purposes only and does not constitute medical advice. Photobiomodulation is not a substitute for prescribed treatment. Consult a healthcare professional.