A Closer Look at Emerging Thinking in Treating Diabetic Neuropathy

It is estimated that as much as 25% of patients living with diabetes will experience painful diabetic peripheral neuropathy (DPN).¹ Treating diabetic neuropathy is something that we as podiatrists deal with daily. Typically, these patients are treated conservatively with medications. These Food and Drug Administration (FDA)-approved treatments include pregabalin (Lyrica, Pfizer), duloxetine (Cymbalta, Eli Lilly), and tapentadol extended-release (Nucynta, Collegium Pharmaceutical). Gabapentin (Neurontin, Pfizer), tricyclic antidepressants, opioid analgesics, topical lidocaine, capsaicin cream, and isosorbide dinitrate spray are also prescribed. In my experience, the success of these treatments does vary among patients, so they are often met with low levels of patient satisfaction and tolerability.

There are several credible new treatments available today that podiatrists should be aware of. Newer prescription medications, medical devices, and procedures may help our patients with diabetic peripheral neuropathy function, and move about, in a better, more pain-free environment, to complete their activities of daily living. 

What You Should Know About a New Capsaicin Formula

While clinicians often prescribe topically applied capsaicin for our patients with painful diabetic neuropathy in strengths ranging from 0.025%–0.075%, a newer medication has higher concentrations of capsaicin. After prolonged use, capsaicin in general can impact the afferent sensory nerve fibers that transmit pain and may also have an effect on sensitization to pain.¹

Qutenza (Averitas Pharma) is a capsaicin 8% topical system indicated for the treatment of pain associated with diabetic peripheral neuropathy of the feet. It’s a single in-office 30-minute procedure that may provide up to 3 months of relief.¹ Available in a patch form, patients can use this medication alone or in concert with other oral therapies. Repeat application of the patches as directed every 12 weeks showed safety and effectiveness when following patients for 1 year.¹

Certain procedures are important during application of this medication, which must take place by a health care provider in that provider’s office. The company website outlines best practices in application, along with recommendations on available billing codes.²

Exploring the Potential of Various Temperature and Pressure Sensors

There are some medical devices that may help our patients with peripheral neuropathy function better and aid them in preventing the development of diabetic foot ulcers (DFU). The FDA-cleared SmartMat (Podimetrics) uses thermometry to determine if there is an early signal that a diabetic skin breakdown is about to occur.³ Patients stand on the mat for 20 seconds each day to record a temperature reading. The temperature is then compared to previous readings. Temperature differences can indicate inflammation on the plantar surface of the feet, that a new ulcer is about to form, or that there may be another condition that needs immediate attention. This reading can be transmitted back to the health care provider, at which point that patient goes to the office for an examination to determine the origin of the abnormal reading. Published data indicates it is advantageous in preventing diabetic foot ulcers that can lead to amputations.³ Currently, the SmartMat is used primarily in the Veterans Administration setting.  

Orpyx SI Sensory Insoles (Orpyx) can demonstrate pressure changes and temperature changes instantly and give alerts.⁴ The insoles are embedded with sensors to monitor pressure, step count, hours of use, and temperature. There is a digital display with cellular data, preconfigured and ready to use out of the box. It also comes with real-time audio-visual alerts to allow immediate relief of high-pressure areas. A step counter allows for activity level dosing, and the insoles come with a state of the art in-shoe wireless charging system. These devices can be worn off the shelf or can be customized just like an orthotic and worn in a diabetic shoe. The Orpyx insoles were used in a randomized control trial that demonstrated an 86% reduction in DFU recurrence compared to control.⁴ There are two types of insoles available; Custom and Flex. Each satisfy different patient needs, and, in my experience, may qualify for coverage under applicable HCPCS and CPT codes. In addition to what this brings to the patient in terms of peace of mind, the available remote patient monitoring codes may allow the provider to follow the patient in the office whenever there are abnormal readings.

The Walkasin (RxFunction) is a “sensory neuroprosthesis” prescription device that can detect plantar pressure during standing and walking activities. Data suggests that it can decrease fall risk in patients with DPN.⁵ This device measure real-time pressure changes during standing and walking activities and transmit the information to the nervous system via gentle sensory stimuli to help improve sensorimotor integration. They provide vibratory feedback to the patient with each step they take so they know where their feet are in space and when their foot touches the ground, which may prevent falls.⁵ Currently, Walkasins are used primarily in the Veterans Administration setting. There is currently no reimbursement for this outside the VA.

Siren Socks (Siren) monitor foot temperature, providing feedback to that can help identify signs of potential injury. The prescription socks are machine washable and must be recharged. They may also notably be used in patients who have undergone amputation, as there is an ipsilateral algorithm available.⁶

All of these modalities provide an opportunity for patients and providers to partner in gathering actionable information that the presence of peripheral neuropathy would traditionally not allow.

Insights On Spinal Cord Stimulation

Spinal cord stimulation is usually one of the last steps in pain management. A recently released systematic review of the literature demonstrated successful  treatment of painful diabetic neuropathy with spinal cord stimulation in several high-quality, multi-center, randomized controlled trials.⁷ Patients using this treatment option typically have had painful diabetic neuropathy for several years, failed multiple medications, and did not have critically uncontrolled diabetes at the time of the spinal cord stimulator placement.⁷ There are many types of spinal cord stimulators available depending on the patient’s individual needs. These can include low frequency, high frequency and burst stimulation. The evidence demonstrates that spinal cord stimulation is an effective and safe option for treatment in these patients.⁷

HFX (Nevro) is one example of a high frequency (10-kHz) spinal cord stimulator used for DPN. A 2021 randomized clinical trial revealed significant pain relief and improved heath-related quality of life over a 6 month period in patients with refractory DPN.⁸

Is Surgical Decompression Effective?

Surgical decompression continues to gain popularity, with a substantial library of research and studies being completed.^9,10 While there is always a need for conservative measures to use early on in treatment, it is reassuring to know that there is a strong body of evidence to support a path for surgical intervention when needed for our patients. I would encourage you to read the website for the Association of Extremity Nerve Surgeons for more information on these procedures.

Podiatrists will frequently encounter cases of diabetic peripheral neuropathy, with its associated potential consequences. Whether pain that impacts quality of life or a lack of sensation that increases risk for ulceration, it is important to understand how new and evolving treatment options could improve outcomes for your patients.

Dr. Garoufalis is certified by the American Board of Foot and Ankle Surgery and the American Board of Podiatric Medicine Prevention/Wound Care. He is also a Certified Wound Specialist by the American Board of Wound Management. Dr. Garoufalis is in private practice in Chicago and also practiced at Jesse Brown VA Medical Center for 39 years and thus has extensive experience in treating the veteran population. He has authored many articles and has lectured extensively across the country, on a variety of topics pertinent to podiatric medicine and surgery and practice management.

Disclaimer: Information regarding coding, coverage, and payment is provided as a service to our readers. Every effort has been made to ensure accuracy. However, HMP and the author do not represent, guarantee, or warranty that coding, coverage, and payment information is error-free and/or that payment will be received.

References
1.     Abrams RMC, Pedowitz EJ, Simpson DM. A critical review of the capsaicin 8% patch for the treatment of neuropathic pain associated with diabetic peripheral neuropathy in the feet of adults. Exp Rev Neurother. 2021; 21(3):259–66.
2.     Qutenza. Available at https://www.qutenza.com/hcp/dpn/
3.     Gordon IL, Rothenberg GM, Lepow BD, et al. Accuracy of a foot temperature monitoring mat predicting diabetic foot ulcers in patients with recent wounds or partial foot amputation. Diabetes Res Clin Pract. 2020; 161:108074.
4.     Abbot CA, Chatwin KE, Foden P, et al. Innovative intelligent insole system reduces diabetic foot ulcer recurrence at plantar sites: a prospective, randomized, proof-of-concept study. Lancet Digital Health. 2019; 1:e308–18.
5.     Koehler-McNicholas SR, Danzl L, Cataldo AY, Oddsson LIE. Neuromodulation to improve gait and balance function using a sensory neuroprosthesis in people who report insensate feet – A randomized control cross-over study. PLOS One. 2019; 14(4):e0216212.
6.     Scholten HJ, Shih CD, Ma R, Malhotra K, Reyzelman AM. Utilization of a smart sock for the remote monitoring of patients with peripheral neuropathy: Cross-sectional study of a real-world registry. JMIR Form Res. 2022; 6(3):e32934.
7.     Henson HV, Varhabhatla NC, Bebic Z, et al. Spinal cord stimulation for painful diabetic peripheral neuropathy: a systematic review. Pain Ther. 2021; 10:895-908.
8.     Petersen EA, Stauss TG, Scowcroft JA. Effect of high-frequency (10-kHz) spinal cord stimulation in patients with painful diabetic neuropathy: a randomized clinical trial. JAMA Network. 2021; 78(6):687–98.
9.     Bregman P, Cancelliere P. Current and emerging insights on treating diabetic peripheral neuropathy. Podiatry Today. 2013; 26(3):36–45.
10. Fadel AT, Imran WM, Azhar T. Lower extremity nerve decompression for diabetic peripheral neuropathy: a systematic review and meta-analysis. Plast Reconstr Surg. 2022; 10(8):e4478.