What is the implant used for treating radicular pain that hasn't responded to conservative treatments?

Spinal Cord Stimulator for Refractory Radicular Pain

For radicular pain that has failed conservative treatments, a spinal cord stimulator (SCS) is the implantable neuromodulation device used to provide pain relief through electrical stimulation of the dorsal columns of the spinal cord. 1, 2, 3

Device Description and Mechanism

A spinal cord stimulator consists of:

• Implantable pulse generator (IPG): Battery-powered device typically placed in the buttock or abdomen 4
• Electrode leads: Placed in the epidural space at the thoracic or lumbar level, depending on pain distribution 2, 4, 3
• External programmer: Allows patient to control stimulation parameters 1

The device delivers electrical impulses to the spinal cord that modulate pain signals, creating paresthesia coverage over the painful area 4.

Mandatory Prerequisites Before SCS Implantation

Before any SCS trial can be considered, the following requirements must be documented:

Conservative Treatment Failure

• Documented trials of first-line neuropathic pain medications (gabapentin, pregabalin, duloxetine, or tricyclic antidepressants) with specific dosages and duration 1
• Structured physical therapy program completion 1
• Simple analgesics and NSAIDs trial documented 5
• Minimum 3 months of conservative management for non-severe radicular pain 5

Psychological Clearance

• Favorable psychological evaluation is explicitly required by the American Society of Anesthesiologists 1
• Absence of untreated psychiatric comorbidity or current enrollment in multidisciplinary pain management 1
• Normal MMPI-3 results and no substance use disorder 6

Medical Safety Requirements

• Coagulation studies to exclude coagulopathy, anticoagulant/antiplatelet therapy, or thrombocytopenia 1
• Documentation that patient can operate the device 1
• Baseline validated outcome measures (VAS, ODI scores) documented 1

Imaging Correlation

• MRI findings must correlate with documented neural compression and clinical presentation 1
• Imaging should be interpreted by specialists with skills to organize, interpret, and act on findings 5

Evidence-Based Treatment Sequence

The following interventions should be attempted before SCS:

1. For cervical radicular pain: Pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion (1B+ recommendation), followed by conventional radiofrequency if insufficient 2

2. For lumbosacral radicular pain:

   • Transforaminal corticosteroid administration for subacute pain under L3 level (2B+ recommendation) 3
   • Pulsed radiofrequency treatment adjacent to the DRG for chronic pain (2C+ recommendation) 3

3. Image-guided epidural steroid injections using fluoroscopic guidance (gold standard) should be attempted before SCS 5

Specific Indications for SCS

SCS is specifically recommended for:

• Failed Back Surgery Syndrome with therapy-resistant radicular pain (2A+ recommendation) 3
• Chronic cervical radicular pain refractory to other treatments, performed in specialized centers 2
• Complex Regional Pain Syndrome (CRPS) that has not responded to other therapies, particularly when trial achieves >85% pain relief 6, 4

SCS should only be considered when:

• Pain is predominantly neuropathic in nature 1
• All conservative treatments have failed 1, 2
• No psychological contraindications exist 1, 6

Trial Period Requirement

A temporary trial period is mandatory before permanent implantation:

• Trial leads are placed and connected to an external generator 6
• Success is defined as >85% pain relief during the trial period 6
• Only patients achieving this threshold should proceed to permanent implantation 6

Complication Rates and Risks

Hardware-related complications occur in 10-29% of cases, including: 1, 6, 4

• Lead migration and connection issues 1, 6
• Infection risk (particularly concerning in patients with active infections) 1
• Wound erosions over the IPG 4
• Post-implantation thoracic radiculopathy (rare but treatable with corticosteroids) 7

Patients must be counseled about:

• Potential need for revision surgery 1, 6
• Possible decrease in pain relief over time 6
• MRI compatibility issues with older systems 8

Common Pitfalls to Avoid

• Do not proceed without psychological clearance: This is an explicit requirement that cannot be bypassed 1, 6
• Do not skip the medication trial documentation: Specific drugs, dosages, and durations must be recorded 1
• Do not implant when imaging shows no neural compression: MRI findings must correlate with clinical presentation 1
• Do not use SCS as first-line treatment: It is reserved for refractory cases after conservative management failure 1, 2, 3
• Avoid blind injections: Fluoroscopic guidance is the gold standard for epidural interventions that should precede SCS consideration 5

Timing Considerations

• Severe radicular pain with neurological deficit: Earlier referral within 2 weeks may be appropriate for image-guided injections or surgery 5
• Less severe radicular pain: Referral to specialist services should occur no later than 3 months 5
• SCS consideration: Only after documented failure of conservative treatments over appropriate timeframe 1, 3