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12 Articles in Volume 17, Issue #1
A Brief History of the FDA’s Role in the Ongoing Effort to Ensure Safe Opioid Use
Distinguishing Neuropathic, Non-Neuropathic, and Mixed Pain
How Can Healthcare Providers Better Advocate for Patients With CRPS?
Ketamine for the Treatment of CRPS?
Letters to the Editor: Opioid Calculator; Metformin
Living With CDC Opioid Guidelines
Neurohormones in Pain and Headache Management: New and Emerging Concepts
Optimizing Neuropathic Pain Relief With Scrambler Therapy
Pain Management and the Elderly
Spinal Cord Stimulation: What Clinicians Need to Know
The Association Between Depressive Disorder and Chronic Pain
Updates in Management of Complex Regional Pain Syndrome

Spinal Cord Stimulation: What Clinicians Need to Know

For patients with chronic radicular pain, axial pain, and patients who are not candidates for surgery, spinal cord stimulation can be a safe and effective therapy, according to a panel discussion at the North American Spine Society's annual meeting.

Proper patient selection is crucial to successful use of spinal cord stimulation (SCS) in pain management, but the timing of SCS, the location of lead placement, and the type of stimulator used also are important factors.

“Spinal cord stimulation is an ideal tool for the right patient, including patients with chronic radicular pain, axial pain who are not surgical candidates, [and patients with] failed back surgery or complex regional pain syndrome,” explained Michael B. Furman, MS, MD, Partner at OSS Health in York, Pennsylvania.

Proper patient selection, placement and timing are key factors to consider when considering spinal cord stimulation.

Dr. Furman chaired a panel discussion on SCS at the 31st Annual Meeting of the North American Spine Society (NASS), recently held in Boston, Massachusetts.1  The session reviewed patient selection, advancements in SCS technology, and tips for integrating SCS into a surgical practice. This article will review highlights of the panel discussion. (Fore more highlights from NASS, click here.)

Guidance on Patient Selection

Patient selection and the timing of SCS placement are both crucial to success of the procedure. The patient selection process involves psychological screening, possible thoracic imaging, consideration of medical history, and an SCS trial. Despite the importance of psychological screening before SCS implantation, Dr. Furman noted that many physicians may not appropriately incorporate these screens into the patient evaluation process.  While thoracic advanced imaging is not necessarily considered a standard of care for patient selection, Dr. Furman said that he often performs thoracic imaging because he has experienced a few cases in which an obstruction prevented him from passing an SCS lead.

Medical history is crucial, providing information about use of anticoagulation therapy, a relative contraindication, as well as any history of traumatic spinal cord injury, lead migration, and infection.

SCS Trial

The SCS trial is another important part of the selection process, Dr. Furman emphasized. As part of this trial, the physician must decide whether to use 1 or 2 leads. This decision depends on a number of factors, including whether the patient had bilateral or unilateral pain, as well as physician preference.

For percutaneous lead placement, Dr. Furman recommended using the fluoroscopic contralateral oblique view, which he called the “safety view,” because it allows visualization of anatomical locations that should be avoided.2

Given the high placebo response rate with SCS trials, which Dr. Furman noted could be as high as 40%, a longer trial duration (5 to 7 days) may help avoid assessment during the “honeymoon phase.” In addition, he explained that some patients will do anything to get better and, thus, may say that they improved during the trial when little symptomatic improvement actually occurred. “You want to walk away from the trial with both you and the patient convinced that they did well with the procedure,” Dr. Furman said.

Temporary vs Permanent Percutaneous Leads

The benefits of using temporary percutaneous leads during SCS trials include reversibility and low morbidity. These leads can be placed and anchored to the skin in an outpatient setting by the surgeon or pain management specialist, explained NASS President Todd Wetzel, MD, a professor of orthopedic and neurological surgery at Temple University School of Medicine in Philadelphia.3 After initial placement of a temporary percutaneous lead, “you can retract the lead a little bit and map it with different real-time paresthesia responses, and get a better guide of where to put the permanent lead,” said Dr. Wetzel.

On the other hand, Dr. Wetzel said, “If I’m convinced that the patient is going to do well with SCS, I put in a permanent percutaneous lead for the trial, with a temporary lead extender placed out to the side, and the patient takes antibiotics for 10 days. If it is a positive trial, the patient goes back to the operating room; I don’t have to move the lead, but rather just remove the temporary extender, tunnel, and put in the pulse generator.”

Dr. Wetzel said he prefers the latter approach, given that it is difficult to place the permanent lead in the exact same place as the temporary lead. He added that approximately 50% of his SCS trials involve permanent percutaneous placement.

The SCS trial also can be performed surgically using a laminotomy, a procedure that Dr. Wetzel said has become easy to perform. This approach requires a general anesthetic with motor and sensory monitoring, and somatosensory evoked potentials or electromyographic mapping.

Dr. Wetzel emphasized the importance of anchoring the SCS lead to the fascia using multiple nonabsorbable sutures. He noted that finding the fascia can be difficult in patients with a body mass index greater than 30 kg/m2. In these patients, he said, “Don’t be afraid to make a ... bigger incision if you have to get to the fascia because it will pay dividends.”

Care for permanent lead placement should involve preoperative antibiotics with no further antibiotics required except in cases of higher-risk patients.

Factors to consider before permanent implantation include whether to use a primary cell (non-rechargeable) device or an SCS with a rechargeable battery. “A good rule of thumb I use in the office is to ask patients if they can use a remote control for their TV or if they use rechargeable batteries for their electronic devices,” Dr. Furman said. “If they are unable to use a remote control or rechargeable batteries, they will most likely be unsuccessful with a rechargeable system.”

In addition, it is important to review patient expectations before permanent SCS implantation. “With reasonable expectations, SCS can work well,” Dr. Furman said.

Advancements in SCS Technology

There are several SCS approaches to consider, depending on whether the goal is to create pain relief with paresthesia (conventional SCS) or without paresthesia using a newer approach with 10 kHz high-frequency stimulation and anatomic lead placement (HF10 SCS). In the latter approach, the clinician uses an external trial generator during the trial that is controlled by the patient. In addition to HF10 SCS, other new trends include burst stimulation and expanded indications for dorsal root ganglion (DRG) stimulation.

HF10 Therapy

Steven M. Falowski, MD, director of functional neurosurgery at St. Luke’s University Health Network, in Bethlehem, Pennsylvania, explained that HF10 is a paresthesia-free therapy that is composed of 4 key attributes: 10 kHz frequency, pulse width amplitude wave shape, consistent lead placement, and a proprietary programming algorithm.4 In a randomized, parallel-arm, non-inferiority study, HF10 therapy demonstrated superiority to conventional tonic SCS with back pain responder rates of 84.3% vs 43.8% and leg pain responder rates of 83.1% vs 55.0% at 3 months (P < 0.001 for both comparisons). These findings were sustained at 12-month follow-up.5

Burst Stimulation

Burst stimulation is establishing itself as a de novo therapy; it also may play a role as salvage therapy in tonic SCS nonresponders and to improve response in tonic SCS responders, Dr. Falowski said. He explained that this technology typically emits 5 signals in a short burst to mirror the physiologic firing of the thalamus. In a study of 102 patients, 95% of responders to tonic SCS had further improvement in pain relief with burst stimulation, Dr. Falowski said.6 In addition, of the 24% of patients who did not respond to tonic SCS therapy, 63% responded to burst stimulation.6

DRG Stimulation

DRG stimulation is approved in the United States for treatment of lower extremity pain in complex regional pain syndrome types 1 and 2. However, Dr. Falowski said that this technology is being used to treat a range of chronic pain conditions that have a focal pain pattern, including post-hernia repair pain, post-hip replacement pain, and post-knee replacement pain. “If you think of any type of focal pain pattern, you can treat it with DRG stimulation,” he said.

Time to SCS Implantation Affects Outcomes

Dr. Falowski reported the results of a study7 showing that “the earlier you intervene with SCS, the more likely you are to succeed. If you intervene on chronic pain within 2 years of the diagnosis, your chance of succeeding with SCS approaches 90%.” However, the average time to SCS implantation is approximately 5 years after diagnosis, when success rates drop to less than 70%, he said. The study findings “mirror the data we see in our own practice,” Dr. Falowski noted.

Integrating SCS Into Practice

SCS is an effective end-stage therapy for properly selected patients with chronic pain conditions. Approximately 70% of SCS users achieve >50% pain relief at long-term follow-up, said Dr. Wetzel. “It is amazing how easily SCS can be integrated in a surgical practice, particularly when you are used to being part of a multidisciplinary team and have the right technical support,” he said.

“The future is here,” Dr. Falowski said. Given the high success rate with SCS and data suggesting that earlier use of SCS is linked to better outcomes, he suggested pain physicians and spinal surgeons should consider SCS earlier in the chronic pain treatment continuum.

The technology and indications for SCS are growing, and the need for increased the use of SCS should be considered in the context of current opinion on use of opioids and spine surgery for chronic pain, he added.

“Everyone knows we have an opioid problem in the United States,” Dr. Falowski said, adding that the Drug Enforcement Agency (DEA) announced in October 2016 that the production of Schedule II opioid agents manufactured in the United States will be reduced by 25% or more in 2017.8

In addition, he cited brain imaging research showing that people without chronic pain who were given 2 mg of morphine for 30 days developed structural and functional changes in reward- and affect-processing circuitry that persisted at 5-month follow-up.9 Thus, there is a need for nonopioid therapies delivered earlier in the treatment paradigm, he said.

Furthermore, he added that spinal surgery has “come under attack” recently, prompted, in part, by the article in The New York Times suggesting that surgeries such as spinal fusion are no better than alternative nonsurgical treatments.10 Dr. Falowski said that he doesn’t think that is true, adding, “I believe fusions and spinal surgery are right for the right patient, just like I believe SCS is right for the right patient at the right time.”  

Rehabilitation, Medications, and Psychological Support

SCS alone is insufficient to manage most patients’ chronic pain, and patients generally also require long-term physical rehabilitation and conditioning, adjuvant medications, and psychological support (preintervention evaluation, directed treatment, and long-term support), Dr. Wetzel said. SCS often will not make a patient medication-free, nor should continued use of adjuvant medication be misconstrued as a failure of treatment, Dr. Wetzel emphasized.

He gave the example of a patient with failed back surgery syndrome who received SCS for neuropathic leg pain. Given that SCS generally is more effective for extremity pain than axial pain, medical management for persistent mechanical low back pain following SCS implantation may be necessary in this type of patient, he said. “Adjuvant therapy with a nonsteroidal anti-inflammatory drug or occasional low-dose opioid … is perfectly reasonable,” he said, “as long as you are doing that as a partnership with pain management.”

Last updated on: August 8, 2017
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