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Neural Engineering
CH.6(2) Deep Brain Stimulation
for Pain Management
2010. 04. 05. Tue.
Kim, Sang Kyong
Special thanks to
6.5
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Indications and Patients Selection
• Patients for DBS
• Chronic intractable pain
• Pain in the lower extremities and back
• Spinal cord stimulation
• Less demanding procedure
 Better choice than DBS
• Pain located in the upper half of the body
• Head, face, neck
• DBS
• Unilateral pain
• VPL/VPM/IC Stimulation
• On the side contralateral to stimulation
• Neurogenic pain
• PVG stimulation
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Indications and Patients Selection
• Patients for DBS
• Deafferentation pain
• VPL/VPM/IC stimulation
• IC stimulation : More effective!
• Pain from brain injury
• Stroke, trauma, etc.
• Pain that has not responded to other modalities?
• Such as spinal cord stimulation or other techniques
• Invalid selection criteria!
• Does not follow that DBS will be effective
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Technique
• Preoperative processes prior to consideration for
surgery
• Psychologic test – Depression, Anxiety, Psychosis
• Detoxification from all narcotic medication
PVG electrode placement
Thalamic and IC placement
Chronic stimulation
6.6.1
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PVG
• Stimulation
• 250 𝝁𝒔𝒆𝒄 pulses
• 20~30Hz
• Gradually increment to 8 volts
• Until side effects are encountered
• Side effects
• Indication of a good target
placement
• Sensation of heat or cold in the
contralateral face
 Excellent electrode placement
• Pinprick sensory test
• PVG  IC  Thalamus
6.6.2
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Thalamic and Internal Capsule
• Stimulation
• Different from those used in the PVG
• 250 𝝁𝒔𝒆𝒄 pulses
• 60Hz
• Gradually increment to 2 volts
• Electrode
• Percutaneous wire exit site
－Inferior and posterior to the electrode insertion
site
－prevention of contamination and infection
• Stimulation test
• 7 days after surgery
• Edema around the electrode －Poor results
• System implantation
• Battery-operated internal pulse generator
• Magnet for turning the device on and off
6.6.2
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Thalamic and Internal Capsule Placement
6.6.2
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Thalamic and Internal Capsule Placement
6.6.3
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Chronic Stimulation
• PVG stimulation
• 20~30Hz
• Only small elevation of its activity
• Most patients cannot feel any side effects
• Rarely requires adjustment
• VPL/VPM/IC stimulation
• Often requires adjustment
• Depression
• Reduction of brain serotonin and norepinephrine levels
• Antidepressants
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Troubleshooting : Patients
• PVG/IC stimulation effect inhibition
• Use of drugs (ex.narcotic)
• Depression
• Depletion of serotonin and norepinephrine
• Use of antidepressants (ex.trazodone, amitriptyline)
• Stress (anxiety, grief)
• Loss of pain relief for unknown reason
• Stimulator off for approximately 2 weeks
• Stop medications (antidepressants)
• Instead,
• L-dopa for norepinephrine production
• L-tryptophan for serotonin production
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Troubleshooting : Device
1. Failure of the insulation or electrical wiring
• Burning sensation over the wiring or connectors
• Leakage of current through the insulation
2. Skin erosion over the electrode
3. Fracture of the wiring and failure of electrical
contact
• Fixation point, usually at the locking plug under the scalp
4. Fracture of the electrode or extension wiring
• Associated with trauma, such as a motor vehicle accident
that produces snapping of the head and neck
5. Battery depletion
6. Failure of stimulation system
• Pain relief remains for about 10 days
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Complications and Side Effects
• Infection
• Less common as more experience has been obtained
• Development of equipment  reducing skin erosion
• Intraoperative antibiotics
• Closure with skin clips that do not perforate the skin
• Cerebral Hemorrhage
• Smooth surface  Prevents from adhering to tissue
• Neurological side effects
• ptosis, hypesthesia, paresis, dysphoria, dysphasia, confusion…
• Electrode placement & Shorter operating time
• Headache
• Still an enigma
• Aggravation of discomfort
• Patient describing paresthesia as pain