What are the benefits of near infrared (NIR) therapy for medical conditions?

Benefits of Near Infrared Therapy

Near infrared (NIR) therapy has limited established medical benefits, with most applications still considered investigational and not well-established for routine clinical use in most medical conditions.

Current Evidence for NIR Therapy Applications

Acute Ischemic Stroke

Near-infrared laser therapy has been investigated as a potential therapy for acute ischemic stroke, but clinical evidence does not support its routine use:

• The American Heart Association/American Stroke Association guidelines explicitly state that transcranial near-infrared laser therapy is not recommended for the treatment of acute ischemic stroke (Class III: No Benefit; Level of Evidence B-R) 1
• Although early studies showed promise in animal models and a small preliminary trial of 120 patients, a larger confirmatory trial of 660 patients only showed a positive trend without definitive benefit 1
• The mechanism of action was theorized to be photobiostimulation, with NIR radiation absorbed by mitochondrial chromophores, accelerating enzymatic activity and ATP production 1

Diabetic Wound Healing

NIR therapy shows some promise in wound healing applications:

• Photobiomodulation therapy using red and NIR wavelengths may speed up diabetic wound healing through alteration of cellular processes 2
• Point-of-care, non-contact NIR imaging devices may help guide clinical decision-making for optimal timing of transition from protective wound dressings to full activity 3
• However, high-quality clinical guidelines do not yet recommend this approach as standard of care

Chronic Foot Ulcers in Diabetes

The evidence for NIR in diabetic foot ulcers is limited:

• A systematic review found that laser therapy studies for diabetic foot ulcers were either unclear, did not show benefit, or used only surrogate outcomes 1
• Most studies were small, unblinded, and at high risk of bias 1
• Current evidence does not support the use of laser therapy over standard care for diabetic foot ulcers 1

Musculoskeletal Conditions and Pain Management

Some evidence suggests potential benefits for pain management:

• A systematic review noted decreased pain levels (measured by visual analog scale) in patients with musculoskeletal disorders treated with IR 4
• Decreased Fibromyalgia Impact Questionnaire scores were observed in subjects with fibromyalgia 4
• However, IR failed to facilitate muscle recovery following athletic injuries 4
• NIR may provide pain relief in neuropathic pain models through different mechanisms depending on irradiance levels 5

Anti-inflammatory Effects

NIR may have anti-inflammatory properties:

• R/NIR exposure most often demonstrates anti-inflammatory effects in immune cell studies 6
• The effects typically involve production of reactive oxygen species, nitric oxide, or interleukins 6
• The specific outcomes depend heavily on radiation spectrum, irradiance, and exposure time 6

Clinical Applications in Medical Imaging

NIR spectroscopy has established diagnostic applications:

• In cardiac surgery, NIR spectroscopy is used to monitor cerebral oxygen saturation, though recent high-quality trials and meta-analyses show no clinical benefit of NIRS-based algorithms 1
• In coronary interventions, NIRS allows characterization of chemical composition of intravascular structures, such as quantifying lipid distribution 1

Limitations and Considerations

1. Lack of standardization: Treatment parameters (wavelength, power density, treatment duration) vary widely across studies
2. Methodological issues: Many studies have small sample sizes, lack proper controls, or have other design flaws
3. Limited high-quality evidence: Few large randomized controlled trials with low risk of bias exist
4. Mechanism uncertainty: The exact mechanisms of action remain incompletely understood
5. Regulatory status: Many NIR devices lack FDA approval for specific therapeutic indications

Conclusion

While NIR therapy shows theoretical promise and some positive preliminary results in certain conditions, particularly in pain management and wound healing, the current body of evidence does not strongly support its routine clinical use for most medical conditions. More rigorous, large-scale clinical trials are needed before NIR therapy can be recommended as standard treatment for specific medical conditions.