Spinal Cord Stimulation for Low Back Pain

Is spinal cord stimulation a safe and effective treatment for low back pain?

When studied for up to six months, spinal cord stimulation likely does not improve pain, function, or health-related quality of life vs. placebo. When studied for up to 12 months, spinal cord stimulation and optimal medical management may slightly improve back function and reduce opioid use. It is also uncertain if spinal cord stimulation can improve outcomes in the immediate term (i.e., less than one month). The long-term adverse effects and complications of spinal cord stimulation have not been quantified and are not fully understood.¹ (Strength of Recommendation: B, inconsistent or limited-quality patient-oriented evidence.)

Chronic low back pain is the leading cause of years lived with a disability and the most common musculoskeletal problem worldwide.² Spinal cord stimulation involves surgically implanting a device in the lower back or trunk that generates electrical impulses and delivers them to the spinal cord via electrodes within the posterior epidural space.¹ The mechanism of action is not well understood but is thought to work using the gate-control theory of pain, in which activation of non-nociceptive nerve signals attenuate pain signals sent to and processed by the brain. Inhibition of sympathetic nervous system activation is also a proposed action. Preimplantation trials are typically performed with percutaneous leads to screen for a response. If a patient achieves at least 50% pain relief, spinal cord stimulation implantation may be considered. The average cost of spinal cord stimulation implantation is $30,000.¹

The authors of this review studied spinal cord stimulation as a potential treatment intervention for low back pain. The review included 13 randomized studies (three multinationals and others in Belgium, Germany, Israel, Poland, the United Kingdom, Norway, and the United States) with 699 participants. Sample sizes ranged from four to 218 participants per trial to assess spinal cord stimulation benefits and harms. Study participants were adults (18 years or older) with chronic low back pain (greater than 12 weeks’ pain duration), with or without leg pain, including people classified as having failed back surgery syndrome. The diversity of participants was not well-described, but the mean age of study participants ranged from 47 to 59 years. Participants with chronic low back pain caused by serious spinal pathology (e.g., fracture, cancer, infection) were excluded. Leg pain was not defined and was not classified as radiculitis vs. radiculopathy. Not all trial reports described a preimplantation trial; seven studies included patients who already had a spinal cord stimulation implant. Scales used to determine effect included a 100-point visual analog pain scale, the 100-point Roland-Morris Disability Questionnaire, and the Oswestry Disability Index.

The primary evaluation was spinal cord stimulation vs. placebo—including a stimulator that was off, turned on for initial programming only, or switched on but not emitting a signal. Primary outcomes included pain intensity, physical function, quality of life, and self-assessed effectiveness from the patient’s perspective. No studies included a follow-up date of more than six months. Of the 13 studies, only one study with a sample size of 50 patients (mean age = 50 years) measured outcomes at six months, with most reporting only immediate-term (less than one month) outcomes. In that study of 50 patients, at six-month follow-up, there was no statistical benefit for spinal cord stimulation on back pain, function, or health-related quality of life.