Diabetic neuropathy (DN) represents a common, disabling and, until recently, largely neglected problem affecting approximately 50% of patients with diabetes at some point. According to the International Diabetes Federation, 425 million people world-wide aged 20 years had diabetes in 2017, and this number is expected to increase to 629 million by 2045. Approximately one in 3 people with diabetes experience painful diabetic neuropathy (PDN).
In this week’s Medical Independent (7th March 2022) Prof. Dominic Hegarty (Clinical Director, Pain Relief Ireland) says that “Ignoring PDN is no longer acceptable because the impact it has on an individual’s quality of life once established can lead to several costly complications including, persistent neuropathic pain, ulcers, Charcot foot, and an increased risk of amputations associated with increased mortality”. A recent cohort study reported that patients with PDN were twice as likely to use opioids and over 16 times more likely to have an amputation than patients with diabetes mellitus without neuropathy.
Medical management was the only option available and it would often fail to control the situation. That is likely to change with the recent research and subsequent approval by the FDA to use of spinal cord stimulation to treatment painful diabetic peripheral neuropathy.
Present Medical management options
Over the past 12 years there have been many reports on the effects of different drugs for the treatment of PDN. A meta-analysis in 2021 where the pain score was used as the main result, and 30 and 50% pain reduction and adverse events were used as secondary results identified 37 studies. Pregabalin and duloxetine have shown good therapeutic effects on painful DPN, but adverse events, which were not unexpected, were also significant. Tapentadol was found to have a good analgesic effect, but due to possible risk of opioid addiction, it needs to be very cautious in clinical use.
The analgesic effects of ABT-894 and gabapentin need to be further studied with longer and larger RCTs. Although lacosamide, mirogabalin, and capsaicin are more effective than placebo, the therapeutic effect is weaker than pregabalin.
Spinal Cord Stimulation as a treatment option
Neuromodulation or modulation of nerve fiber activity at the spinal cord (SCS) is an established treatment option for neuropathic pain such as failed back surgery syndrome and complex regional pain syndrome. In July 2021 the FDA approved the use of SCS to treat PDN especially for those who have not responded to traditional medical management and in whom their diabetes is under reasonable control. For the first time individuals with PDN now have a treatment that can provide have a meaningful improvement on activities daily living.
The concept of SCS is that it provides focused electrical current on the dorsal column to counter balance the painful signals thereby providing symptom relief. It does not eliminate the pain source but it changes the way the brains perceives the pain. The devices themselves can be programmed to influence the pain pathway personalising the therapy (Figure 1).
Evidence of clinical improvement
Overall SCS has shown a mean reduction in pain intensity of 23.13 (95% CI 24.19 to 22.08) for the management of PDN with SCS when compared with basic medical therapy (BTM). Statistically significant differences were also observed for the proportion of patients achieving at least a 50% pain reduction, EQ-5D utility index, and EQ-5D VAS; all showing beneficial effects of SCS compared with BMT for patients with PDN.
Ability to personalise treatment
The ability of SCS devices to deliver differ types of stimulation patterns is an important advancement. This ability greatly increases the chance of improving outcomes for those with PDN. For example randomised controlled trials evaluating high-frequency SCS at 10 kHz for PDPN have shown a greater improvement in the proportion of patients with at least a 50% reduction in lower-limb pain without a clinically meaningful neurological deficit compared with baseline at 3 months (SCS (86%) when compared with patients receiving conventional medical management alone (5%). Encouraging results have also been reported in a case series and a small cross-over RCT evaluating burst SCS for PDN. Randomised controlled trials evidence is required to ascertain the effectiveness of burst SCS for PDN. The use of conventional SCS parameter should also provide pain control and the introduction of Differential Targeted Multiplexed SCS (DTM) programming that involved the stimulation for the glia cell in the dorsal column could also provide another useful control point in the pain pathway.
Although the effectiveness of conventional paraesthesia inducing SCS for PDN has been demonstrated, its cost-effectiveness has not yet been established. A cost-utility analysis from a societal perspective should be conducted based on the outcomes of SCS.
Spinal Cord Stimulation at Pain Relief Ireland
At Pain Relief Ireland we have over 15 years of experience in the field of spinal cord stimulation for many different indications. Prof. Hegarty believes that “patient selection for implantation of spinal cord stimulator is the key to success. We spend a lot of time trying to understand the needs of an individual and how best to manage their pain. For some spinal cord stimulation is the answer and we will work with each individual to give a very personalise therapy plan using the best technology devices on the market”
At Pain Relief Ireland we work with the key MedTech leaders in the field including Medtronic, Boston Scientific and Nervo to provide many individuals with the type of treatment that their condition requires. Fortunately, all the health insurers in the Irish Market are prepared to cover the cost of this specific expensive treatment once certain criteria are met. We know that the partnership Pain Relief Ireland has build up with the best technology firms with excellent technical support, this provides each individual with the best opportunity to improve outcomes no matter what the indication.
The new indication for those with painful diabetic neuropathy in another exciting time in the era of drug-free medical management of chronic illness.
FIGURE 1: SCS uses either (a) low-frequency current to replace the pain sensation with a mild tingling feeling called paraesthesia or (b) high-frequency or burst pulses to mask the pain with no tingling feeling. This inhibits the transmission of painful sensations to the brain based on the ‘Gate Control Theory’
If you, or your patients suffer from chronic neuropathic pain no matter what the cause and you feel they may benefit from clinical review please contact us and we will be delighted to help.
Pain Relief Ireland, where personalised pain relief matters!