Neural Engineering CH 61 Deep Brain Stimulation for
Neural Engineering CH. 6(1) Deep Brain Stimulation for Pain Management 2010. 04. 01. Fri. Kim, Sang Kyong Special thanks to
6. 1 2 Electrical Stimulation of the Brain • Since the early 20 c • Low potential for side effect • Potential to affect previously untreatable pain Who Heath When Early 1950 s Where • Septal area Target Effects Patients with terminal cancer Pain relief Patient with Schizophrenics Pain relief Pool et al. 1956 • Septal area Patients Pain relief Ervin 1966 • Thalamus Patients Pain relief Gol 1967 • Septal area Patients Pain relief
6. 1 3 Electrical Stimulation of the Brain
6. 1 4 Electrical Stimulation of the Brain Who When Reynolds 1969 Mayer et al. 1971 Richardson ? Akil, Richardson 1970 Richardson Early 1970 s Where Target Effects • Periaqueductal gray(PAG) Rat Deep analgesia • PAG Rat (Stimulation produced analgesia) 1 Patient with cancer pain Pain relief SPA (Human) 5 Patients SPA Patients Chronic pain relief • During stereotaxic Leisoning procedure (not exactly) • PAG • Periventricular(P VG) • PVG • PAG SPA in animal
6. 1 5 Electrical Stimulation of the Brain
6. 1 6 Electrical Stimulation of the Brain Who Target Effects Early 1970 s • Dorsal Column Peripheral nerve Patients Pain relief Chronic pain relief 1960 • Ventral posterior lateralis (VPL) • Ventral posterior medialis (VPM) Patients Pain relief Hosobuchi et al. Early 1970 s • VPM • Internal capsule (IC) Patients Relief of Anesthesia dolorosa Young et al 1992 3 patients Analgesia Richardson Marzars et al. When Where • Lateral upper brainstem
6. 1 7 Ventral view Ventral Posterior Lateralis (VPL) Ventral Posterior Medialis (VPM)
6. 1 8 Internal capsule v
6. 1 9 Brain stem
6. 1 10 Periventricular gray (PVG) Internal capsule (IC) v (PAG)
6. 2 11 PVG & PAG stimulation • PVG or PAG • Stimulation SPA • Different effect for each of the sites selected • Mechanism • Best understood • But, most complex • Direct effect? • NO! • By naloxone effect – SPA inhibition • More complex mechanism • Cell bodies for the central opiate mechanism • Mu system • Arcuate, infundibular, and periventricular nucleus of the hypothalamus • Axons from hypothalamus to raphe nuclei
6. 2 12 PVG & PAG stimulation
6. 2 13 PVG & PAG Hypothalamus Raphe nucleus
6. 2 14 Side effects of DBS • Different side effects • PAG • Osilopsia • Epigastric rising syndrome • Patients will not allow long stimulation • PVG and septal area • Mild euphoric • Basal forebrain and hypothalamus • Elevation of BP
6. 2 15 Mechanism • Dorsal level • Fibers Serotonergic fiber Norepinergic fiber • Intermediate opioid interneuron • Activated by these tracts • Pain inhibition at the first synapse in the dorsal horn • PAG, PVG stimulation • Activating the same system • Pain relief in dorsal level
6. 2 16 Mechanism • Thalamic level or brainstem level • Inhibition of propagation of impulses through the spinoreticular tracts and the spinothalmic tracts • Inhibition of input to the spinal cord > central mechanism • Activation of this system • (Akil et al. ) • Endogenous opiates release • Naloxone • Blocking analgesia in animal • Reducing analgesia in humans
6. 2 17 Mechanism • Direct activation of the cells in PAG and PVG • (Fessler et al. ) • Activation of serotonergic and norepinergic mechanisms in the cord • Blocking of monoamine mechanisms • (Yaksh et al. ) • SPA reduction • PVG stimulation • (Young et al. ) • Release of beta-endorphin • Release of methionin enkephlelin • PVG and PAG stimulation • Opiate fibers activation
6. 2 18 PVG & PAG
6. 3 19 Thalamus & Internal Capsule • Inhibitory mechanism of stimulation • Thalamus & Internal capsule • Remains Obscure • In the cat • Sectioning of the dorsal columns below the level of activation Not completely obliterate the pain-reducing effects • Sectioning of the dorsal columns above and below the level of activation Complete deactivation of pain inhibition
6. 3 20
6. 3 21 Dorsal column
6. 3 22
6. 3 23 Dorsal column • Single cell recordings in the sensory thalamus • On/off mechanism activated by dorsal column stimulation • Complex inhibitory mechanism • Interaction btw sense fibers and the pain transmission system • Sense fibers • The proprioception, touch, and position • Dorsal column • Pain transmission system • Dorsal horn • Synapses in the brainstem, thalamus, and cortex of the brain • Marzars et al. in 1960 • Stimulation of the somatosensory pathways in the cord Pain relief • Ervins et al. in 1966 • Stimulation of the sensory thalamus Pain relief
6. 3 24 Chronic stimulation • Chronic thalamic stimulation • (Hosobuchi et al. ) • For anesthesia dolorosa • Lose its effectiveness over time • Programmed type of stimulation • Ramping or intermittent stimulation Good pain relief • Possibility of parensthesia in the area of the patients’ pain Accurate placement of the electrodes
6. 3 25 Internal capsule • Internal capsule stimulation • (Hosobuchi et al. ) • For neospinothalamic stimulation • More effective • Less likely to produce sensory loss • Electrode insertion in the main sensory nucleus • Resulting in areas of focal sensory loss • Face or Hand Trouble! • Insertion of electrodes into the internal capsule • Does not seem to produce sensory loss • Unclear reason • Probably fibers are less vulnerable than cell bodies to the trauma of electrode insertion
6. 3 26 Inhibitory mechanism • Stimulation of the dorsal columns • Main sensory relay nuclei of the thalamus and internal capsule • Activation of touch and proprioception fibers • Inhibition of pain • “Gate theory of pain transmission” • The effect of VPL/VPM/IC , dorsal column stimulation • Multilevel • Activation of VPL/VPM/IC • More effective for pain relief
6. 4 27 Electrode • Original electrode • Solid silver with silver balls(1 mm in diameter) at the tip • Last only few weeks due to chloridization • Degradation of contact btw electrode balls and the brain tissue • 1 st generation chronic electrode • Four-contact pull-down electrodes • Platinum/iridium • Semirigid • Electrode Migration • 5 mm deep to the original placement • CSF loss brain sagged
6. 4 28 Electrode • Solution to the migration of electrodes • Change the electrode wiring material • Platinum/iridum wire(semirigid) Pure platinum wire(flexible) • Electrode replacement • Possible to scar • Intracerebral hemmorrhage • Hemiplegia • Death • Old electrode clipped at the cortex • Recent electrode • Smooth • Prevents glia from infiltrating or adhere to its surface • Battery-operated internal pulse generator(IPG) • Problem of battery replacement
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