Spinal Cord Stimulation: Indications and Patient Selection

Presentation Transcript

Joshua M. Rosenow, MD, FACS

Associate Professor of Neurosurgery

Director, Functional Neurosurgery

Northwestern Memorial Hospital

Disclosures

Consultant:

Boston Scientific Neuromodulation
Medtronic Navigation

FBSS Etiologies

Poor patient selection

Abnormal psychometrics
Chronic pain behavior
Unreachable expectations

Incorrect diagnosis
Wrong procedure

Wrong level or site

Poor technique

Nerve root injury
Iatrogenic instability or flat back syndrome
Pseudarthrosis
Incomplete decompression or incomplete correction of deformity

Progressive disease

Recurrent disk herniation or spinal stenosis
Transition syndrome

Indications for Surgery

Compressive lesion
Associated radiculopathy
Demonstrable neurologic deficit
Clear instability / deformity

CRPS Diagnostic Criteria

Revised Diagnostic Criteria

Pain and sensory changes disproportionate to the injury in magnitude or duration
At least 1 symptom in 3 or more categories and 1 sign in 2 or more categories

Sensory
Vasomotor
Sudomotor/edema
Motor/trophic

Harden RN and Bruehl SP. Introduction and diagnostic considerations. Complex Regional Pain Syndrome: Treatment Guidelines. RSDSA press. 2006:1-11.

Surgical Contraindications

Thecal sac compression by tumor
Significant spinal deformity
Severe emaciation
Significantly low WBC, plt
Coagulopathy
Ongoing infection
Unsuccessful trial

SCS: Patient Selection

Pain syndrome amenable to stimulation

Radicular preferable to axial
Neuropathic preferable to nociceptive

Failed reasonable medical management

Several pharmacologic classes
Dose titration until adverse side effects or lack of response noted

Surgical disease ruled out

Reoperation vs. stim?
Not surgical candidate?

Pain psychological evaluation

Patient Factors

Set appropriate expectations!!!!

Takes time, but will be worth the investment

They need to understand this is not a cure!
Seeing the patient multiple times before moving to a trial helps gauge their goals of therapy and probable compliance level

Patient Factors

Can they be a reliable partner with a subjective therapy?
Can they give appropriate feedback in the OR?
Can they manage the device?

Rechargeable vs primary cell IPG

Other Treatments

Should proceed in parallel
Psychological counseling
Behavioral treatments
Physical therapy and conditioning
Vocational counseling and rehab
Implantables can’t fix everything!

Psychosocial Factors

Present in ALL chronic pain patients
Can include:

Depression
Personality disorders
Drug and alcohol problems
Return to work issues
Social and family discord
Many others

Pain Psychology

Spine surgery success in the presence of:

Childhood physical or sexual abuse,
Emotional neglect/abuse
Abandonment
Chemically dependent parents:

# FactorsSurgical Success

1 95%

1-2 73%

3 or more 15%

(Shofferman et al., 1992)

Predictive value of psychological testing

Many studies have examined the value of psychological testing in predicting success with SCS

Daniel et al calculated an 80% accuracy rate using the MMPI and BDI for predicting success.
Burchiel et al. found that the BDI score and mania scale on the MMPI emerged as predictors. Less helpful in a subsequent study.
Long et al reported a 33% success rate in unscreened patients compared with 70% in screened patients.

Trial Techniques

Trial implant

Easiest

Fastest

Remove electrode in office

Low prob candidates

If multiple choices or procedures debated

If location not suitable for trial extension

Requires reimplant of electrode at permanent implant

“Permanent Trial”

Permanent implant easier
Remove electrode in OR
If finding therapeutic location 2nd time will be difficult
If implant technique difficult or invasive
If general anes needed for permanent system

Paddle Trials

Lumbar fusion or laminectomy precluding percutaneous insertion
Inability to access the epidural space percutaneously

Bony anatomy
Obesity

Prior procedure in the region of the implant

Tumor resection, etc.

Preop imaging is essential

You would never do any other spine case without adequate preop imaging – DON’T START NOW
Preop imaging makes sure something asymptomatic doesn’t become symptomatic
Aids in counseling patient preop if procedure needs to be altered to deal with anatomic issue