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12 Articles in this Series
Introduction
Central Post-Stroke Pain – How Central Is It?
False-Positive Urine Drug Monitoring Results and Aspirin
Medical Marijuana & Pain
More Potential Uses for Low-Dose IV Naloxone
On the Horizon: A Brief Look at Potential Analgesics of the Future
Preview of PAINWeek 2018 - Know Before You Go
Stem Cells & Beyond
Underlying Causes of Small Fiber Neuropathies
Understanding Sexual Pain – A Physical Therapist’s Perspective
Video: Drs. Gudin & Fudin on PAINWeek 2018 and PPM's Future
Where Does the Patient-Centered Pain Practitioner Stand Today?
Why Interventional Tactics Should be Used for Chronic Pain Patients Now, Not Later

Why Interventional Tactics Should be Used for Chronic Pain Patients Now, Not Later

Advances in radiofrequency ablation and spinal cord stimulation have paved the way for earlier approaches. A PAINWeek 2018 highlight with Paul J. Christo, MD

 

In a talk titled “Injections, Nerve Bocks, Pumps, and Spinal Cord Stimulation,” Paul J. Christo, MD, called out perhaps a lesser-discussed portion of the CDC Guidelines on Prescribing Opioids for Chronic Pain – the encouragement of practitioners to use interventional procedures. Dr. Christo is an associate professor of anesthesiology and director of the Multidisciplinary Pain Fellowship program at Johns Hopkins University in Baltimore, and a member of the PPM Editorial Advisory Board. In his PAINWeek 2018 presentation, in Las Vegas, he discussed interventional therapies from a primary care angle, including steroids, injections, and surgeries.

Interventions for Low Back Pain

Low back pain is one of top three chronic pain conditions, noted Dr. Christo, and common spinal procedures to treat low back pain may include, for example: epidural steroid injections (ESI) for disc herniation, interlaminar epidural steroid injection for lumbar pain, and caudal epidural steroid injection for post-surgical back pain. The latter is a great technique for the treatment of shooting leg pain, he added, as clinicians can access all the way up to L4 or L5 through the tailbone. For ESI, in particular, ideal candidates may include those with:

  • radiculopathy caused by herniated disc
  • short duration of pain
  • leg pain to back pain (signs of tension)
  • no psychological overlay
  • young age
  • self-employed
  • intermittent pain.

More unfavorable outcomes may occur in those with:

  • degenerative disk disease or spinal stenosis
  • pain that has lasted 6 months or longer
  • back pain to leg pain
  • psychological overlay
  • constant pain
  • unemployment
  • poor imaging correlation
  • previous failed interventions.

Dr. Christo also reviewed transforaminal epidural steroid injection, an approach that involves targeting a specific nerve root, such as the L5, by inserting the needle under fluoroscopy, using contrast, steroid, local anesthetic, and saline. “Remember that the epidural space is anterior as well as posterior,” he advised, so if a patient’s pain is emanating from the posterior, an injection in that space may have a better outcome.

According to Dr. Christo, 60% of more than 40 controlled studies show short-term benefit (ie, 6 months or less) with transforaminal ESI, while evidence of longer-term benefit is limited. For lumbrosacral radicular pain, “outcomes with interlaminar and transforaminal ESI are rather good and about equal in their ability to provide pain relief and function improvement,” he said. The transforaminal approach may also prevent the need for surgery in chronic sciatica patients.

Interventions for Facet Joint Pain

Blocks

Facet joint disorders represent another major cause of pain. Facet joint pain may be caused by whiplash, joint arthritis, spine surgery, trauma or inflammation, and the pain may refer up and down. Lumbar Facet Syndrome, in particular, may present as axial back pain that worsens with extension but, pointed out Dr. Christo, radiographic evidence of facet arthropathy may not always be visible.

While some practitioners still inject into the joints, current treatment approaches target the medial branches. This technique helps to protect against axial rotation and shearing forces, and may assist any affected discs in resisting compressive forces, he explained.

In general, blocks of the facet joints may be ideal for patients who present with deep aching pain on both sides of the neck, low back, shoulder, or thorax. Blocks should only be performed after achieving 50% relief upon a local anesthetic trial. Additional clinical success predictors of radiofrequency denervation for lumbar facet syndrome may include: paraspinal tenderness, the absence of pathopsychology, and fewer levels in need of treatment. Since nerves regenerate, the block may not last more than six months but the procedure may be repeated. The approach is similar for neck pain, using cervical facet blocks.

Cooled Radiofrequency for Sacroiliac & Knee Pain

The prevalence of sacroiliac (SI) joint pain is often underestimated in primary care, said Dr. Christo, but this condition represents 15 to 30% of axial back pain cases below L5. Referral zones include the buttock, thigh, and lower lumbar. Intra-articular (IA) injection under x-ray or CT, while the patient lies on his/her stomach, is a typical treatment with controlled studies demonstrating short-term relief. However, shared Dr. Christo, the SI joint may also be denervated to provide longer-term relief in those who obtained temporary relief from blocks. In these cases, the lateral branches may be targeted. Further, there is evidence that cooled radiofrequency denervation may provide 3 to 12 months of SI joint pain relief. Compared to conventional RF systems, cooled RF is spherical (versus elliptical), removes the constraints of tissue charring, and increases the lesion size 2-fold.

Dr. Christo also discussed the use of cooled radiofrequency for chronic knee pain stemming from osteoarthritis. Cooled RF ablation may target the genicular nerves via outpatient procedure, he explained, and some patients still report relief at one year, including improved knee function. To compare, he shared studies by Davis, et al, and Santana Pineda, et al, published in Reg Anes Pain Medicine, in which only 16% of IA steroid patients reported relief at 6 months compared to 50% of those who underwent a cooled radiofrequency procedure.

Spinal Cord Stimulation

Dr. Christo focused the final portion of his PAINWeek presentation on Spinal Cord Stimulation (SCS) and available devices. With these devices, patients can control the on/off feature and change the frequency. Conventional batteries last 2 to 5 years, while newer models are rechargeable and may last 9 to 10 years, he shared.

Proper candidates for SCS implantation include those with failed back surgery syndrome, radicular pain, postlaminectomy pain, degenerative disc disease, Complex Regional Pain Syndrome (CRPS), interstitial cystitis, epidural fibrosis, arachnoiditis, and more controversially so, ischemic leg pain that is inoperable and refractory angina. SCS trials are first carried out under fluoroscopy, again with at least 50% relief demonstrated in a pre-intervention trial. A pain psychology review is also typically required by insurance before implantation. When successful, SCS patients may find improvement in pain level and function, as well as improved mood and sleep.

While SCS may block and/or reverse central sensitization as shown in animal studies, Dr. Christo said that “there is growing evidence and feeling that we should offer SCS early, not 10 years after numerous failed treatments” as the intervention may help to suppress pain by triggering brain pain processing areas.

Abbott, Boston Scientific, Medtronic, Nevro, Nuvectra, and StimWave are among those manufacturers who offer approved SCS devices and, said Dr. Christo, each one has its unique benefits. Nevro’s device, for instance, does not produce parasthesias, he said, so just looking for pain relief in a trial is remarkable compared to other devices. This high-frequency stimulation device has also demonstrated better controlled back and leg pain based on a study by Kapural L, et al, he said. Stimwave’s wireless miniaturized system has no implantable batteries and can be worn in the patient’s shirt. A wire placed in the epidural space can be placed along dorsal root ganglion (DRG). DRG stimulation is approved for CPRS in the United States, and for even more conditions in Europe; it offers more precise targeting and less energy requirements. DRG stimulation may also help to prevent unintentional stimulation due to the separation of sensory and motor fibers.

The SCS success rate overall is 85% in patients who are implanted within 2 years of receiving a chronic pain diagnosis compared to 8% when implanted in those who have had chronic pain more than 15 years. So “instead of waiting many years to offer device, offer it sooner if you have candidates,” he advised. Most systems become cost-effective around 2.5 years (ie, the payoff period).

Peripheral and Intrathecal Systems

Peripheral nerve stimulators (eg, Bioness) may also be an asset for treating neuropathic pain caused by post-traumatic or post-surgical neuralgia, intercostal neuralgias, entrapment syndromes, upper extremity and lower extremity pain, or trunk pain. For instance, Dr. Christo noted that he has seen success in patients with post-stroke shoulder pain. With these devices, the needle is placed and activated near the affected nerve. The data on these is still preliminary data but it is positive so far with reports of 3 months up to 1 year of pain relief, said Dr. Christo.

Last but not least, Medtronic’s intrathecal drug delivery system may be placed right or left lower quadrant of the abdomen, with catheter tunnels running from the pump to the intrathecal space, where medication is delivered. These systems are useful in treating intractable cancer pain as it can reduce opioid doses and allows bypass of gastrointestinal tract, thus resulting in fewer side effects, noted Dr. Christo, who said he would like to see more oncologists refer for this system as they may not be aware of its potential.

Why Intervene Now

Overall, Dr. Christo reinforced that the CDC guideline on prescribing for chronic pain poses procedural interventions as alternatives to opioids. There is good evidence for short- and long-term benefit of epidural steroid injections for radicular pain; of cooled radiofrequency for sacroiliac or knee joint pain; of spinal cord stimulation for neuropathic pain; of pumps for refractory pain; and now, the emergence of less invasive peripheral nerve stimulation. With so much available and intriguing in the interventional space, why make your patients wait for relief?

Dr. Christo disclosed he is a consultant to GlaxoSmithKline Consumer Healthcare and does Media Work with Algiatry, LLC.

More on this topic with John Markman, MD.

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