Neurostimulation for Pain: Neurosurgical Considerations

Northwestern University Department of NeurosurgeryNorthwestern University Department of Neurosurgery

Neurostimulation for Pain: Neurostimulation for Pain:

Neurosurgical ConsiderationsNeurosurgical Considerations

Joshua M. Rosenow, MD, FACSJoshua M. Rosenow, MD, FACSDirector, Functional Neurosurgery

Associate Professor, Department of Neurosurgery

Northwestern Memorial Hospital


SCS: Patient SelectionSCS: 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

*North, et al. Stereotact Funct Neurosurg 1994;62:267-272.


Patient FactorsPatient Factors

Set appropriate expectations!!!! Takes time, but will be worth the investment

Prepare patients for the procedureInvolve them in the process

i.e. IPG placement


Surgical ContraindicationsSurgical Contraindications

Thecal sac compression/significant spinal stenosis

Significant spinal deformity

Severe emaciation

Significantly low WBC, plt

Coagulopathy

Ongoing infection

Inability to assess patient response to trial

Psychological contraindications

Patient compliance issues

Medication abuse issues

Unsuccessful trial


General PrinciplesGeneral Principles

Adequate length of trial

Choose appropriate hardware

Simulate everyday life during trial, within limits

Confirm location and ensure stability of electrode

Prevent infection

Prepare for permanent implant

Permanent system should be stable, flexible and convenient

Prepare for revisions


MAC vs. GETAMAC vs. GETA

Airway/body habitus

Comorbidities

Procedure to be performed/region of operation

Anticipated intraoperative difficulties

Need for intraoperative verification of coverage

Patient preference

Patient ability/willingness to cooperate

If GETA - consider neuromonitoring for protection and confirmation


Why use paddles?

Previous difficulties with perc leads

Preference of implanter

?lower current requirement

?less interference by epidural fat


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.


Paddle LeadsPaddle Leads


Laminotomy Lead Placement

Plan incision centered 1 disc space below desired entry point Incision centered on T10-11 will lead to entry at T9-10

and paddle will cover T8-9 bodies

Rongeur both upper and lower spinous processes to

flatten angle

Small central lamintomy through ligamentum flavum

Carefully dissect epidural space and insert electrode

Avoid pressure on spinal cord

Securely anchor to deep tissues


Paddle issuesPaddle issues

Where does the paddle go?

Assessing canal adequacy for paddle

Clearing the epidural space

The paddle won’t go straight


Guess the level!Guess the level!


Communication is keyCommunication is key

T9T9

T10T10


Preop imaging is essentialPreop 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


Preop imaging is essentialPreop imaging is essential

Where is the cord???

The cord may not respect the spinal column midline

Paddle may look great on fluoro and not provide adequate coverage


Paddle issues in the ORPaddle issues in the OR

Dissecting epidural space Careful You’re a surgeon – use surgical tools

No – paddle lead, passing deviceYes – dural separator, narrow tip malleable brain ribbon

Anywhere but straight Straight paddle in curved space Epidural adhesion Unilateral extension vs. “reach around” laminotomy


Epidural fibrosisEpidural fibrosis

Careful dissection

Use appropriate instruments

Don’t over-reach

Decompress if you need to do so

Suture paddle to dura if possible

Fibrin glue

Postop abdominal pain


Complication avoidanceComplication avoidance

Don’t be overzealous

Don’t push a bad situation If it won’t go, it won’t go…

Caution when dissecting laterally – epidural veins

Poor coverage despite radiographic adequacy check trial fluoros make sure c-arm aligned in both planes


Don’t be THAT surgeonDon’t be THAT surgeon

Paddle placed under GETA

Awoke with right thoracic radicular pain

Never had good coverage with stim

Surgeon told him to “wait a year and see if the coverage and pain improve”


Don’t make more cases!Don’t make more cases!


To Extend or Not to Extend

PRO Adds slack to system May make revision less invasive May be needed to adapt electrodes to IPG Needed for “permanent trial”

CON Another electrical connection Another wire that may break Connector adds bulk and may not be suitable for some locations Direct connection to IPG may reduce slack in system and add tension to

electrode

In either case, there should be a relaxing loop of electrode in the electrode incision site


IPG Considerations

Location location location Patient comfort Cosmesis Ease of remote interface Ease of recharger interface (if rechargeable) Ease of implant Ease of revision

Rechargeable vs. Primary cell


Possible IPG Locations

Buttock Cervical or lumbar SCS ONS Peripheral LE stimulation

Axillary ONS Cervical SCS

Abdomen DBS/MCS ONS SCS

Infraclavicular Trigeminal ONS DBS/MCS Cervical SCS UE peripheral stimulation

SQ lower extremity


ConclusionsConclusions

Rational treatment plan improves outcomes

Good patient selection important

Technique is key, as always

Goal: not “do implants” but TREAT PAIN


E-mail: E-mail: [email protected]@nmff.org

Thank you for coming!Thank you for coming!

Phone: Phone: 312-695-0495312-695-0495

Neurostimulation for Pain: Neurosurgical Considerations

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