Anesthesia and Deep Brain
Stimulation
Dr.Amr Sobhy
Objectives
Brief History
 Indications and contra-indications
 The DBS surgical procedure
 Anesthetic consideration
 Anesthetic technique
 Safety issues

Brief History

Basal ganglia have been targeted for neuromodulator surgery
since the 1930s.
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1950s: Pallidotomy was the accepted procedure for the
treatment of Parkinsonism Disease (PD).

procedures were irreversible and were associated with several
permanent side effects.
With the advent of L-dopa (1968),this surgery largely stopped.
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Limitations of dopaminergic therapy led to a resurgence of new
surgical techniques directed at basal ganglia targets in early
1990s.
Brief History

1993: Bilateral high-frequency stimulation of subthalamic
nucleus (STN) introduced in treatment of advanced PD

Pioneering studies & empirical observations during surgery
showed that DBS improved PD patient’s motor function and
quality of life.

Today, DBS has become a non-lesioning alternative to
pallidotomy.
What is DBS?

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A surgically implanted
medical device called a
brain pacemaker.
Sends electrical impulses
to the brain.
Traditionally used to treat
movement disorders such
chronic pain,
Parkinson’s
disease, tremor,
and dystonia.
as
Mechanism
The exact mechanism is incompletely
understood .
 may differ depending on the site of
stimulation, The primary target sites :

1.
2.
3.
Vim = ventralis intermedius nucleus of the
thalamus
GPi = posteroventral portion of the internal
segment of the globus pallidus
STN = subthalamic nucleus
Mechanism


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stimulation of the STN causes hyperpolarization or
“neuronal jamming,” and this consequentially
results in the inhibition of its activity.
Stimulation of the GPi nuclei may result in
activation (GABA)ergic axons, which in turn
inhibits GPi neurons.
In contrast, stimulation of the Vim nucleus of the
thalamus activates output to the neurons in the
reticular nucleus, which then sends inhibitory
efferent back to the thalamic nuclei.
Contra-indications
patients clearly have to be fit enough
to undergo the surgery and well
enough to benefit from it.
 The major concern is of
coagulopathies, as this would
increase the risk of hemorrhage with
the electrode insertion

Components
Three Major
Components

Implanted pulse generator (IPG)

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Lead

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battery-powered neurostimulator
encased in a titanium housing,
which sends electrical pulses to the
brain to interfere with neural activity
at the target site
coiled wire insulated in polyurethane
with four platinum iridium electrodes
and is placed in one of three areas
of the brain
Extension

insulated wire that runs from the
head, down the side of the neck,
behind the ear to the IPG, which is
placed subcutaneously below the
clavicle or in some cases, the
abdomen
The DBS surgical procedure
The DBS surgical procedure

Precise
implantation
of
stimulation
electrode in targeted brain area.

Connecting
electrode
to
programmable pulse generator
internal
The DBS surgical procedure
Pre-Operative Stage:

Stereotactic Surgery
-
Locate targeted brain areas
Stereotactic frame
MRI, CT, or ventriculography
Stereotactic atlas
The DBS surgical procedure
Pre-Operative Stage:

Functional Stereotactic
Surgery
- Electrophysiological exploration
of targeted regions via test
electrodes
- Involves:
1. Microrecording
2. Test-stimulation
The DBS surgical procedure
Electrode-Stimulator Connection:


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Electrode  Extension (passed
under skin to chest)  Chest:
Battery-operated stimulator
Patient turns stimulator “on” and
“off” by passing magnet over the
skin overlying stimulator
Typical stimulator settings:
- Voltage amplitude: 2-3 V
- Pulse width: 90 μs
- Stimulation frequency: 130-185
Hz
Anesthetic consideration
1- Patient-related considerations
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Primary disease (Parkinson disease, dystonia,
essential tremors, chronic pain, and epilepsy)
Comorbid medical conditions of patient and of
disease
Age (children and elderly)
Appropriate patient selection and preparation
Polypharmacy and altered pharmacokinetics and
dynamics
Potential drug interactions
Medication “off state”— worsening of symptoms
Anesthetic consideration
2- Procedure-related considerations
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Different locations of patient care (magnetic
resonance imaging and operating room)
Use of a stereotactic frame: potential for difficult
airway
Positioning of patient on the operating room table:
difficult with movement disorders
Semisitting position: risk of venous air embolism
and hypovolemia
Blood pressure control: prevention of hemorrhage
from hypertension during electrode insertion
Anesthetic consideration
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Microelectrode recordings: anesthetic effects may
impair
Macro stimulation testing: need for an awake and
cooperative patient
Long duration of procedure: patient fatigue
Complications: airway obstruction, seizures,
neurologic deterioration, and hypertension
Anesthetic technique
Anesthetic management
Stage of Framing
 Overall, the majority of patients tolerate the
insertion of DBS using a combination of local
anesthesia and sedation/analgesia
 infusion of dilute Remifentanil usually 0.02–0.05
mg/ kg/ min OR Dexametamedonie usually 0.40.7µg/ kg/ h
 Oxygen is provided by a microphone supply
attached to the underside of the frame, and music
of the patient’s choice played to aid relaxation.
Anesthetic management
Stage of Imaging

the anesthetist is equipped with
the tool to remove the fixing
screws, in case the frame needs
to be removed for access to the
airway
Anesthetic management
Stage of implantation

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Awake: an infusion of remifentanil as
above, while full monitoring and
supplemental oxygen is provided.
Benzodiazepines are avoided
G.A:
typically
a
target-controlled
infusion of propofol and remifentanil and
a non-depolarizing neuromuscular block
technique is used.
If the patient has Parkinson’s disease,
then it is prudent to insert a nasogastric tube
Safety Issues
G.A & R.A

avoiding drugs with extra-pyramidal side-effects in
this group of patients.
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

.
Peripheral nerve stimulators can still be used
MRI scanning
Heating, Magnetic field interactions and DBS
function This can produce Unintended stimulation
thermal lesions possibly resulting in coma,
paralysis, or death.
contraindicated
Safety Issues
Diathermy
Can damage the DBS leads and can also cause
temporary suppression of the neurostimulator.
 use bipolar diathermy.
 if unipolar diathermy is necessary:
(a) use only a low-voltage mode.
(b) use the lowest possible power setting.
(c) keep the current path (ground plate) as far from
the neurostimulator
(d)After using diathermy, confirm that the
neurostimulator is functioning as intended

Safety Issues
External defibrillation

position defibrillation paddles as far from the
neurostimulator as possible.
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position defibrillation paddles perpendicular to the
implanted neurostimulator-lead system.
use the lowest clinically appropriate energy
output.
Confirm that the DBS is functioning correctly after
any external defibrillation.
Safety Issues
Electroconvulsive therapy
 ECT may be a safe and effective
option.
 Care in placing the ECT electrodes.
 Switching the DBS off before ECT.
 Limiting the number of ECT sessions
should be considered.
Any
Questions?
summary
DBS is the pace maker of the brain.
 Anesthetic consideration of PD during
insertion
should
be
consider
especially withholding of the drugs
and early resume postoperatively.
 Dealing with patient have DBS devise
need especial care as regard
electromagnetic interference (MRIDiathermy-External defibrillation).

Thank you