Deep brain stimulation (DBS) is a well-established and effective treatment for motor symptoms
resulting from idiopathic Parkinson's disease (PD). During the DBS surgery , a brain
electrode is implanted in the basal ganglia, which is involved in the pathophysiology of the
disease. The surgery consists of three steps: 1. Opening the skin, drilling the skull bone
and inserting a temporary electrode. 2. Recording electrical activity of the brain,
electrical stimulation of the brain which guide the implantation of the electrode.3
Transferring wires and implanting a subcutaneous pacemaker battery in the chest area.
Today, standard treatment protocols consist undergoing the second stage (or first and second
stage, depending on the treatment center protocol) of the surgery awake (under local
anesthesia only). As systemic anesthetics affect cerebral electrical activity and prevent
patient cooperation, they inhibit precise identification of the cerebral target under
'physiological navigation' guided by electrical recording and brain stimulation. As a result,
the accuracy of electrode implantation decreases. However, undergoing surgery in an awake
format often causes severe patient discomfort and anxiety necessitating shortening the length
of surgery or aborting the surgery.
As such there is a need for establishing an alternative anesthesia protocol for DBS
surgeries.
Ketamine is considered a unique anesthetic due to its hypnotic properties, analgesia, and
possible amnesia. Standard doses of ketamine are currently used worldwide to treat patients
with various injuries and brain diseases. Research from monkeys has shown that ketamine (in
low dose) does not affect electrical brain activity used for physiological navigation.
The investigators therefore propose a prospective , randomized , blinded study to evaluate
the utility of low dose of ketamine in the second stage of DBS surgeries for increasing
patient satisfaction and cooperation without detracting from the accuracy of physiological
navigation to the cerebral target.
This study will compare two treatment arms :
Treatment arm consisting of patients randomized to receive a low dose of ketamine for the
second stage of DBS surgery.
Control arm consisting of patients randomized to receive sham control of saline during the
second stage of DBS surgery.