Treating Peripheral Neuropathy: Multi-Faceted Approach Including Laser Therapy

Peripheral neuropathy affects at least 20 million people in the United States¹ and nearly 60 percent of all people with diabetes suffer from diabetic neuropathy. Many suffer from the disorder without ever identifying the cause.² Because of its prevalence and impact on quality of living, appropriate evaluation and treatment are imperative. It all starts with knowledge, the critical starting point when dealing with peripheral neuropathy.

Common Signs / Symptoms

Signs and symptoms of peripheral neuropathy may include the following:³

• Gradual onset of numbness and tingling in the feet or hands, which may spread upward into the legs and arms
• Sharp / jabbing / burning pain
• Extreme sensitivity to touch
• Lack of coordination / falling
• Muscle weakness or paralysis if the motor nerves are affected

Possible Causes

Some of the common causes of peripheral neuropathy are: diabetes, alcoholism, auto-immune diseases, poisonings, heavy metals, certain medications, chemotherapy, viral and bacterial infections, trauma, and vitamin deficiency.³

As you can see from this list, determining the causal factor(s) is important for each case. Secondary management of the cause (diabetes, infection, etc.) needs to be addressed, along with any treatments directed toward managing the patient's peripheral neuropathy. Trying to manage peripheral neuropathy for a patient with uncontrolled diabetes, for example, would prove to be futile.

Examination Tips

The examination required is not a standard exam. It is multi-faceted. A comprehensive sensory exam including light and deep touch, vibration test, sensitivity to hot / cold and pin prick are all good starting points.

Carefully documenting the area of involvement is also important. Note the skin texture, tone, color and any abnormalities such as pitting edema, or dryness, scaling and flaking skin.

A complete motor examination should be done, testing both large and small muscles; and paying particular attention to any indications a specific spinal level is affected. A reflex examination testing MSRs is necessary. Don't overlook joint position sense for large and small joints. There are several good examples of these types of examinations on YouTube. Watching a few also will help you streamline the flow of your examination.

For some finer points, vibration testing is performed using a 128 C tuning fork over a distal joint in most cases. If you test the most distal joint – for example, the great toe – and the patient reports good sensation, then there is no need to test more proximally.

So, what is good sensation? The Vibration Perception Scoring Chart comes in handy.⁴ A firmly struck 128 C fork should be felt for 10 seconds or more over the great toe DIP:

• 0 = felt >10 seconds (normal)
• 1 = felt 6-10 seconds (mild loss)
• 2 = felt <5 seconds (moderate loss)
• 3 = not felt (severe loss)
• 8 = unable to or did not assess

Reviewing the dermatomes of the foot and lower limb is always a good idea; it's important to be able to differentiate the lateral plantar distribution from the sural nerve, etc.

Having a monofilament testing kit to scientifically test for light-touch sensation is a must. These kits range wildly in pricing, so careful research should be conducted before purchasing.

Recommendations: Multi-Faceted Treatment

Nutrition is a good start for your patient. Consuming plenty of fruits and vegetables rich in vitamins and antioxidants is important. These will feed the nerves and help to destroy the free radicals.

As we age, our spine begins to degenerate, causing compression on spinal nerves and roots. This compression leads to classic symptoms of neuropathy.

According to a study published in the British Medical Journal in 2004, chiropractic adjustments, "with or without exercise, improved symptoms more than medical care did after both 3 and 12 months."⁵ And in 2008, the Journal of Chiropractic Medicine reported that "patients showed an 85.5% resolution of the nerve symptoms after only 9 chiropractic treatments."⁶

Dozens of home remedies, from a turmeric-based paste to ginkgo biloba, are readily available as well; along with physical measures such as contrast baths and therapeutic massage. As long as there are no side effects or contraindications, it might be worth a multi-faceted approach.

While several drugs on the market can offer varied amount of relief, the extent of the neuropathy has an impact on how effective most interventions are. More severe, long-term cases are more difficult to manage, as one might expect. However, most of the medications only work to manage the symptoms and do not address a correction.

Super-Pulsed Laser Therapy

This brings us to a treatment that can offer more than just pain relief: super-pulsed laser therapy. SPL has long been established as an effective modality for pain.^7-8 SPL offers a variety of positive benefits, including improved blood flow and stimulating nerves.⁹ The blood flow improvements come from a photochemical reaction whereby the laser photons cause a release of nitric oxide – a powerful vasodilator that also exerts an anti-inflammatory effect.¹⁰

SPL stimulation also helps on a synaptic level, and aids in the uptake and production of neurotransmitters by a photochemical reaction, photochemotherapy. PHT stimulates oxyhemoglobin to release an oxygen molecule that is readily available for cellular respiration.¹¹ And evidence suggests treating the dorsal horn with SPL can inhibit substance P release and the synapse, aiding in pain relief.¹²

When it comes to managing peripheral neuropathy, the road to recovery can be long and slow, with small victories. It is important to set goals for treatment and follow through with the protocols fit for your diagnosis. Don't give up after a few weeks. Changes will come slowly and it is important to be consistent.

References

1. Peripheral Neuropathy Fact Sheet. National Institute of Neurological Disorders and Stroke.
2. Nerve Damage (Diabetic Neuropathies). National Institute of Diabetes and Digestive and Kidney Diseases.
3. Peripheral Neuropathy: Symptoms and Causes. Mayo Clinic.
4. Yang Z, et al. Scoring systems to screen for diabetic peripheral neuropathy. (C. M. Group, Ed.) Cochrane Database Systematic Rev, 2014 Mar 4;3.
5. Spinal manipulation gives value for money. BMJ, 2004 Dec 11;329(7479).
6. Christensen KD, Buswell K. Chiropractic outcomes managing radiculopathy in a hospital setting: a retrospective review of 162 patients. J Chiro Med, 2008 Sep;7(3):115-125.
7. Leal-Junior ECP, et al. Adjunctive use of combination of super-pulsed laser and light-emitting diodes phototherapy on nonspecific knee pain: double-blinded randomized placebo-controlled trial. Lasers in Med Sci, 2014 Nov;29(6):1839-1847.
8. Bjordal JM, et al. Low-level laser therapy in acute pain: a systematic review of possible mechanisms of action and clinical effects in randomized placebo-controlled trials. Photomed Laser Surg, 2006 Apr;24(2):158-168.
9. Avci P, Gupta A, Sadasivam M, et al. Low-level laser (light) therapy (LLLT) in skin: stimulating, healing, restoring. Seminars Cutaneous Med Surg, 2013 Mar;32(1):41-52(12).
10. Manchini MT, et al. Amelioration of cardiac function and activation of anti-inflammatory vasoactive peptides expression in the rat myocardium by low level laser therapy. PLoS One, 2014 Jul;9(7):e101270.
11. Eells JT, et al. Mitochondrial signal transduction in accelerated wound and retinal healing by near-infrared light therapy. Mitochondrion, 2004 Sep;4(5-6):559-567.
12. Chow R, et al. Inhibitory effects of laser irradiation on peripheral mammalian nerves and relevance to analgesic effects: a systematic review. Photomed Laser Surg, 2001 Jun;29(6):365-81.