ANESTHESIA FOR PARKINSON DISEASE

PATIENT

Rizq Alamri

OUTLINES

• Parkinson disease • Deep brain stimulation surgery and its

anesthestic concerns• anesthesia for patients with pre-existing deep

brain stimulator systems

Dorsey et al.2007

Projected Increase in Prevalence of PD by 2030

Parkinson’s Disease is increasing• Affects 1 in 100 older than 60 years• 5-10% diagnosed with PD are less than 40 yrs. old• No social, ethnic or geographical boundaries

BIOCHEMICAL PATHOLOGY

• is decreased dopamine neurotransmission in the basal ganglia.

• most parkinson syndromes have degeneration of the nigrostriatal dopamine system with marked loss of striatal dopamine.

• in some – striatal degeneration with loss of dopamine receptors occurs.

Putamen

Motor Cortex

MotorThalamus

PremotorCortex

+ Glutamate

- GABA

Gpe

Gpi

STN

Dopamine

SNpc

+

-

PATHWAYS 1

Putamen

Motor Cortex

MotorThalamus

PremotorCortex

+ Glutamate

- GABA

Gpe

Gpi

STN

Dopamine

SNpc

+

-

PATHWAYS 2

Putamen

Motor Cortex

MotorThalamus

PremotorCortex

+ Glutamate

- GABA

Gpe

Gpi

STN

Dopamine

SNpc

+

-

PATHWAYS 3

INITIAL SYMPTOMS OF PARKINSON DISEASE

• 60% of substantia nigra dopaminergic neurons already lost at onset

• Dopamine content of striatum is only 20% of normal

• Motor symptoms are prominent , i.E. Tremor, stiffness & slowness, loss of dexterity, gait disturbance, and muscle aches, pains and cramps.

• S.N. Pathology: black brown tan

SIX CARDINAL FEATURES

Rest tremor

Rigidity

FLEXED POSTURE

BRADYKINESIA – HYPOKINESIA

LOSS OF POSTURAL REFLEXES

FREEZING PHENOMENON

TO DIAGNOSE: two of above with at least being rest tremor OR bradykinesia

Clinical Presentation

NON-MOTOR SYMPTOMS OF PARKINSON DISEASE

• Behavioral symptoms :depression, anxiety, decreased motivation, personality changes, less inclination to speak, bradyphrenia

• Sensory non-specific pains, akathisia, restless legs and other sleep problems

• Autonomic constipation, bladder dysfunction, impotence, low blood pressure

Pharmacological Treatment of Parkinson’s Disease

• Goals:• Primary = restore dopamine receptor function.• Secondary = inhibition of muscarinic cholinergic

receptors.

• Several types of drugs:• Levodopa• Dopamine Receptor Agonists• Monoamine Oxidase Inhibitors (MAOIs).• Catechol-O-Methyltransferase (COMT) inhibitors.• Muscarinic Cholinergic Receptor Antagonists.• Amantidine.

Pharmacological Treatment of Parkinson’s Disease

From: Youdim et al. 2006. Nature Rev Neurosci. 7: 295-309

CURRENT SURGICAL INTERVENTIONS

• Thalamotomy/ Thalamic Stimulation• Mainly used for tremor - essential,

MS• Other targets preferred for PD

• Pallidotomy/Pallidal Stimulation• Effective for all cardinal features

Considerable experience

• Subthalamic Stimulation • Most recent addition • Several theoretical advantages• Currently most popular therapy

DEEP BRAIN STIMULATION

• is used to treat Parkinson disease and other neurologic conditions, as well as certain psychiatric disorders

• The indications for DBS have now expanded to include other conditions, and the number of centers performing this procedure has also increased .

• The DBS system provides advantages over traditional surgical ablative procedures such as thalamotomy and pallidotomy, because it is non-destructive, reversible, and adjustable

PATIENT SELECTION

• Inclusion Criteria- Idiopathic Parkinson's Disease- Symptoms for four or more years- Documented response to levodopa

therapy- Medically refractory disease?

• Exclusion Criteria- Patients unable to communicate- Patients unable to cooperate for

surgery- Dementia- Abnormalities on pre-operative MRI- Medical contraindications to surgery

• Movement Disorders Team Evaluation- Initial screening- Insure that medical therapy is optimized- Neurologic evaluation using validated

clinical rating scales- Psychiatric Evaluation- Neuro-psychologic Evaluation- Neurosurgical Evaluation- Consensus opinion at weekly

conference

• The deep brain stimulation (DBS) hardware has three main components:

1. Multicontact intracranial quadripolar electrodes2. A programmable single- or dual-channel internal

pulse generator (IPG) with battery unit3. An extension cable connecting the DBS

electrodes to the IPG

• Stage one : is usually done under sedation.

• Stage two : is usually done under General anesthesia.

DBS TARGET SITES FOR MOVEMENT DISORDERS

Vim Thalamus: Essential Tremor

Subthalamic Nucleus: Parkinson’s disease

and Dystonia

Globus Pallidus: Parkinson’s disease

and Dystonia

• Subthalamic nucleus is small (5 x 7 mm) and difficult to visualize using current MRI and CT technology

SUBTHALAMIC NUCLEUS

BRAIN MAPPING

Frame-based imaging to identify the target nuclei

Target localization with the use of microelectrode recording

Macro stimulation testing

FRAME-BASED IMAGING

• A stereotactic head frame is usually applied using local anesthesia

• With the stereotactic frame in place, magnetic resonance imaging (MRI) is performed to identify target nuclei, allowing the surgeon to establish external coordinates for electrode insertion.

• Alternatively, computerized tomography (CT) scanning can be used, if MRI is contraindicated or not possible in an individual patient.

MICROELECTRODE RECORDING

• Is a fine tune localization of the target sites.

• The neurophysiology team obtains MERs to detect and amplify the activity of individual neurons

Stereotactic Localization

Micro Drive

• A microelectrode is inserted to a point 10 to 15 mm above the target, then slowly advanced in 0.5 to 1.0 mm increments while its tip records and amplifies neuronal discharges along its path.

MICROELECTRODE RECORDING

9

10

1

2

3

4

6

7

8

11

12

5

De

pth

in

(m

m)

Para-sagittal Section - 12 mm lateral

Thalamus

ZonaIncerta

SubthalamicNucleus

TremorCell

ElectrodeTrajectory

1 sec

PHYSIOLOGIC LOCALIZATION

MACROSTIMULATION TESTING

• the patient is awake during surgery, allowing the team to briefly activate the implanted deep brain electrode in order to confirm clinical improvement (efficacy) and detect any adverse side effects during neurostimulation

PREOPERATIVE EVALUATION AND PREPARATION

• Use of the stereotactic head frame and airway compromise:

regardless of the original anesthetic plan, meticulous airway assessment is imperative to assess the risk of potential airway compromise and to formulate a plan for urgent airway management.

all equipment necessary to remove the stereotactic head frame should be immediately available throughout the procedure.

• Blood pressure control:Hypertension is a common perioperative problem

and is associated with increased risk of intracerebral hemorrhage.

It is important to treat hypertension immediately to minimize the risk of intracerebral hemorrhage during electrode insertion.

• long-standing Parkinson disease

autonomic dysfunction impaired respiratory reservepoor cough reflexsleep apneaincreased risk for aspiration

• challenging Patient:

Patient with psychiatric conditionPatients with chronic pain require special

consideration

INTRAOPRATIVE CARE

After applying appropriate monitoringSedation drug selection:Novel drug should be:Airway and respiratory sparing Attenuate responses to surgical stimulation Does not interfere with Microelctrode recording or macrostimulation and patient evaluation.

• Dexmedetomidine : a dose of (0.3 to 0.6 mcg/kg/hour) provides

sedation from which patients are easily aroused and cooperative with verbal stimulation.

Low-dose infusion does not ameliorate clinical signs of Parkinson disease, and anxiolysis can be achieved with no effect on MER

• Propofol has been widely used as a continuous infusion, either alone or in combination with opioids, especially in cases involving lead placement in the subthalamic nuclei

The extent to which propofol interferes with MER localization is not clear, although it is known to cause dyskinesia and abolish tremor

Propofol has the desirable properties of rapid onset and short duration of action.

• Short acting opioids are commonly used as analgesics because of their minimal effect on MER

Opioids may cause worsening of rigidity especially in high doses

• Benzodiazepines should be avoided as these drugs can abolish MER and also interfere with stimulation testing

PERIOPERATIVE COMPLICATIONS IN DBS

• Airway and respiratory complications 1.6 to 2.2 %

• Hypertension is a common perioperative problem

• Hypotension may occur due to autonomic dysfunction

• Venous air embolism can occur at any time during the burr hole procedure, either in the supine or in the semi-sitting position

especially in a hypovolemic patient

The incidence of venous air embolism is reported to be 4.5%

PERIOPERATIVE COMPLICATIONS IN DBS

• Seizures: are the most common neurological complication, occurring in 0.8 to 4.5 % of patients having DBS placement

• Intracranial hemorrhage is rare Intracranial hemorrhage is suspected in an awake

patient when there is a sudden change in mental status or occurrence of a focal neurological deficit

POSTOPERATIVE CARE

• vigilance of the hemodynamic and respiratory parameters in the immediate postoperative period as increased chances of respiratory depression present

• Care must be taken to start antiparkinsonian drugs as soon as possible, either through the nasogastric tube or orally to avoid potential risk of exacerbation

“ON” Time Without Dyskinesias Improves from 27% to 74%

‘ON’ without Dyskinesia‘ON’ with Dyskinesia ‘OFF’

Before Surgery(n=96)

49%

27%

23%

6 Months After SurgeryBilateral STN Implant

(n=91)

74%*

19%

7%

* The Deep-Brain Stimulation for Parkinson’s Disease Study Group. Deep-brain stimulation of the subthalamic nucleus for the pars interna of the globus pallidus in Parkinson’s disease. N Eng J Med. 2001;345:956-63.

DBS Improvement in PD

PD MOTOR SYMPTOMS IMPROVEMENT MAINTAINED AFTER 5 YEARS

OFF-Medication Motor Score Improvements*

6-month 1-year 3 years 5 years

Tremor 79% 75% 83% 75%

Rigidity 58% 73% 74% 71%

Akinesia 42% 63% 52% 49%

• In a 5-year study, DBS significantly improved OFF-medication assessments of tremor, rigidity, and akinesia/bradykinesia

*Results for STN

Journal of the Formosan Medical Association DOI: (10.1016/j.jfma.2013.09.006) Copyright © 2013 Terms and Conditions

OVERALL COMPLICATION

ANESTHESIA FOR PATIENTS WITH PRE-EXISTING DEEP BRAIN STIMULATOR

SYSTEMS • identification of the device and the status of the

severity of the patient’s symptoms when the implanted DBS system is turned off.

• If deactivation of the device results in severe symptoms, oral medication should be started before turning the device off on the day of surgery.

ANESTHESIA FOR PATIENTS WITH PRE-EXISTING DEEP BRAIN STIMULATOR SYSTEMS

• DBS systems may produce artifacts and interfere with the recording of an ECG

• Intraoperative electrocautery has the potential to burn neural tissue around the stimulator or to reprogram the device

•  Use of bipolar electrocautery is safer

• the paddles must be positioned as far away as possible from the generator and the lowest clinically-appropriate energy output should be used

• Electroconvulsive therapy, radiofrequency neuro-ablation, and peripheral nerve stimulation have been reported to be safe if the stimulator is turned off and the probes are placed far away from the generator

CONCLUSION

• There is good evidence from randomized controlled trials to endorse deep brain stimulation (DBS) of either the subthalamic nucleus (STN) or the internal globus pallidus (GPi) as an effective therapeutic option for

• DBS is non-destructive, can be performed bilaterally with low neurologic morbidity

• DBS surgery is growing up in functional brain surgery including psychiatric and behavior illness