5.cme event 2014 -- handout - uc davis health · • basal ganglia review – physiology (rate...
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Deep Brain Stimulation:Surgical Process
Kia Shahlaie, MD, PhDAssistant Professor
Bronte Endowed Chair in Epilepsy ResearchDirector of Functional Neurosurgery
Minimally Invasive NeurosurgeryDepartment of Neurological Surgery
University of California, Davis
UC Davis Deep Brain Stimulation Program
Outline
• Brief history• Basal ganglia review
– Physiology (rate model)– Parkinson’s disease
• DBS Procedure– Step 1: direct, indirect, physiological targeting– Step 2: pulse generator implantation
• Postop care and outcomes– Programming– Risks and benefits of DBS
UC Davis Deep Brain Stimulation Program
Irving Cooper (1922‐1985)
• Born in Atlantic City, NJ– Son of a salesman– Worked his way through school
• BA, MD, MS, PhD, NSG residency
– Faculty at NYU, then NYMC
• Pioneer in functional neurosurgery– Anterior choroidal artery ligation…
Cooper IS: Parkinsonism: Its Medical and Surgical Therapy. Springfield, Ill: Charles C Thomas, 1961
UC Davis Deep Brain Stimulation Program
What do the basal ganglia do?
• Scale Movement – amplitude and velocity
• Focus Movement– select specific muscles – suppress antagonist muscles
• Rate Model:
DIRECT
INDIRECT
HYPERDIRECT
Direct: Facilitate “wanted” movementsIndirect: Inhibit “unwanted” movements
UC Davis Deep Brain Stimulation Program
Rate Model
STRIATUM
THALAMOCORTEX
BASAL GANGLIA GPi
UC Davis Deep Brain Stimulation Program
Rate model explains kinetic disorders
Hypokinetic disorders:Parkinson’s disease
Hyperkinetic disorders:Dystonia, hemiballism, HD
Delong, TINS 1990:13, 281‐285
UC Davis Deep Brain Stimulation Program
Focused excitation/surround inhibition model of BG function
Nambu Neurosci Res 2002Mink Prog Neurobiol 1996
DIRECT
INDIRECT
HYPERDIRECT
UC Davis Deep Brain Stimulation Program
XX
Rate model provided the rationale for basal ganglia surgery in PD
• Loss of DA input to striatum– Direct pathway is underactive– Indirect pathway is overactive– NET: Excess inhibition of thalamocortical relay
• Nuclei that are overactive in PD– STN (driving the GPi)– GPi (inhibiting the thalamus)
UC Davis Deep Brain Stimulation Program
GPi and STN are overactive in PD
Loss of dopaminergic activity results in disinhibition of the STN and GPi
normal:
PD:
STNGPi
UC Davis Deep Brain Stimulation Program
DBS Surgery for PD• Indications
– Clear diagnosis of idiopathic PD– Continued good motor response to dopamine– Motor fluctuations and dyskinesias from meds– Independent ambulation in best “on” state
• Contraindications– Dementia– Age > 80years (?)– Poor function in best “on” state– Poor MD/patient relationship
• Unilateral/bilateral– Cognitive status, laterality of symptoms
UC Davis Deep Brain Stimulation Program
Goals of DBS surgery
• Primum non nocere!– “elective” operation
• Accurate implantation– Location, location, location– Awake, stereotactic surgery
1) Indirect targeting 2) Direct targeting 3) Physiological targeting
– Microelectrode recording/mapping– Test stimulation
• Adjustable, reversible system
STN
Zona incerta
Red nucleus
Medial lemniscal pathway
AXIAL PLANE
Oculomotor nucleus of CN III
Brain Orientation
SNr SNc
CN III nerve roots
STN
Zona incerta
Red nucleus
Medial lemniscal pathway
AXIAL PLANE
Oculomotor nucleus of CN III
Brain Orientation
SNr SNc
CN III nerve roots
UC Davis Deep Brain Stimulation Program
DBS Surgery Steps
1) Indirect targeting2) Direct targeting3) Physiological targeting
UC Davis Deep Brain Stimulation Program
Indirect TargetingDevelop 3D coordinate system
Define AC, PC, and 3 midline points 3D map with MCP at 0,0,0mmUC Davis Deep Brain Stimulation Program
Indirect TargetingSelect target based on atlas data
Vectors STN
X (lateral)
12mm
Y (ant/post)
‐3mm
Z(sup/inf)
‐4mm
UC Davis Deep Brain Stimulation Program
Direct TargetingRevise based on direct visualization, internal landmarks
Along anterior edge of red nucleus on axial
3mm lateral to edge of red nucleus
2mm below superior edge of red nucleus
UC Davis Deep Brain Stimulation Program
Direct TargetingSelect entry point and trajectory
Entry‐ Avoid cortical veins‐ Enter crest of gyrus‐ Burr hole location
Trajectory‐ Avoid sulci‐ Avoid ventricle‐ Avoid subependyma‐ Avoid major
parenchymal vessels
UC Davis Deep Brain Stimulation Program
Day of surgery…
Head frame placed using local anesthesia
Localizer box used for CT –
provides fiducials
Merge with MRI plan
Patient placed in comfortable position,
then sedated
UC Davis Deep Brain Stimulation Program
DBS Surgery
Prepped and draped.Incision and burr hole placed.
Stereotactic head frame set to proper coordinates
mER with patient awake
UC Davis Deep Brain Stimulation Program
Physiological Targeting: mERSubthalamic nucleus (STN)
Goal: Dorsolateral motor territory of STN
‐‐ leg area is medial‐‐ arm area is lateral
Globus pallidus internus (GPi)
Goal: Posterior motor territory of GPi
‐‐ leg area is dorsal/medial‐‐ arm area is ventral/lateral
UC Davis Deep Brain Stimulation Program
Physiological Targeting: Test Stimulation
Subthalamic nucleus (STN) Globus pallidus internus (GPi)
UC Davis Deep Brain Stimulation Program
Interpreting STN Test Stimulation
STN
Zona incerta
Red nucleus
Medial lemniscal pathway
Oculomotor nucleus of CN III
SNr SNc
CN III nerve roots
STN
Zona incerta
Red nucleus
Medial lemniscal pathway
Oculomotor nucleus of CN III
SNr SNc
CN III nerve roots
Error Structures Side effect
Too lateral
IC: CBTIC: CSTFEF fibers
DysarthriaTonic contractionsContra gaze dev
Too medial
CN3Red nucleusLimbic STN
DiplopiaParesthesia, flushPersonality
Too posterior
Med Lemnisc Parasthesia
Too anterior
IC: CSTIC: CBTHypothalam
Tonic contractionsDysarthriaFlushing
UC Davis Deep Brain Stimulation Program
Intraoperative Imaging: iCT
Standard OR, equipment, surgical technique; awake surgery with mERUC Davis Deep Brain Stimulation Program
Post‐implantation MRI
Subthalamic nucleus (STN) Globus pallidus internus (GPi)
UC Davis Deep Brain Stimulation Program
Hospital stay: 1 night
UC Davis Deep Brain Stimulation Program
Stimulator Implantation
Outpatient surgery (same day discharge, general anesthesia)UC Davis Deep Brain Stimulation Program
Clinic follow‐up for programmingPhysician programmer
Patient programmer
Contacts/monopolar/bipolar Voltage Frequency Pulsewidth
monopolarC+/1‐
Bipolar0‐/1+
UC Davis Deep Brain Stimulation Program
Benefits of DBS for PD
~ 30% improvement in motor scores
~ 40% improvement in ADL scores
~ 50% reduction in PD medication needs
DBS is typically as effective as “best” dopamine response…Likely to improve: Tremor Rigidity (tightness) Bradykinesia (slowness) Dystonia Dyskinesia*
Unlikely to improve:• Gait instability / falls• Freezing of gait• Speech• Swallow• Cognitive deficits
UC Davis Deep Brain Stimulation Program
Risks of DBS surgery
from Starr PA and Silay C, 2008
• Infection: 5‐10%• ICH/hemorrhage: 2‐4%• Neurological deficit: <1%
UC Davis Deep Brain Stimulation Program
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