Movement Disorder Surgery

Question 1

Pathophysiology of Parkinson’s Disease

Answer 1

Degeneration of dopaminergic neurones in the substania nigra compacta leads to dopamine deficiency and interrupts normal neuronal pathways in the cortico-striatal-pallidal-thalamic-cortical
(CSPTC) network

Question 2

Selection of patients for Deep Brain Stimulation

Answer 2

• Idiopathic Parkinson’s disease refractory to medical management
• Essential tremor impairing daily life despite optimal medical management
• Primary dystonia despite optimal medical management and failed botox injections
• Must have well-controlled medical co-morbidities and be in good general health
• Mild cognitive impairment is a relative contraindication and must be looked at on a case-by-case basis
• Any more severe impairment, psych issues and refractory depression are contraindications

Question 3

Types of stereotactic frames

Answer 3

• Leksell frame
• Cosman-Roberts-Wells frame
• Riechert-Mundinger frame

Question 4

Complications from Deep Brain Stimulation Surgery

Answer 4

• Intracranial haemorrhage (0.2-12.5%)
• Infection of lead
• Migration of lead
• Fracture of lead
• Skin erosion
• Neuropsychiatric complications- depression, mania, apathy, hallucinations

Question 5

Perioperative considerations for patients undergoing deep brain stimulation surgery

Answer 5

Disease Related Factors
- Tremor- difficulty positioning
- Autonomic dysfunction
- Risk of aspiration (delayed gastric emptying & pharynx dysfunction)
- OSA

Medication-Related Factors
- Levodopa- risk of hyperpyrexia on acute withdrawal
- Avoid metoclopramide and droperidol

Procedure Related Factors
- Rigid head frame limiting airway access in the awake patient
- Possible need to transfer to MRI
- Long procedure leading to patient fatigue

Question 6

Anaesthetic Techniques for Deep Brain Stimulation Surgery

Answer 6

GA- Prop/ Remi, Arterial line, unable to perform electrophysiological monitoring
Conscious Sedation- Article recommends dexmedetomidine bolus 0.5mcg/kg followed by infusion of 0.2-0.6mcg/kg/hr, risk of under or oversedation
LA only- no risk of sedation/ GA, difficult as long surgical time and specific positioning required

Question 7

Perioperative Complications of Deep Brain Stimulation Surgery

Answer 7

• Airway complications
• Aspiration
• Laryngospasm
• Syncope
• Arrhythmias
• Confusion
• Intracranial Bleeding
• Seizures
• Venous Air Embolism
• Parkinson Hyperpyrexia Syndrome

Question 8

Anaesthetic Considerations for patients with DBS having other surgery

Answer 8

• Remote controlled- turn off DBS after induction and turn on after surgery before emergence
• Avoid monopolar diathermy where possible, place pad away from DBS
• MRI is possible dependent on type of DBS
• ECT is contraindicated
• External defib- ?