Prof. YILMAZ prefers to perform DBS with the patient awake, so that microelectrode recording and microstimulation can identify the best electrode position for each patient. When dystonia is very severe, or when a patient does not wish to be awake, the operation is performed under general anesthesia. Instead of placing the permanent electrode directly, Prof. Atilla YILMAZ, MD first passes on average three thin test microelectrodes on each side of the brain, records the electrical signals of the brain cells along each track, and then sends small test currents through each one. The track that gives the best result for that patient is chosen for the permanent electrode.
This process is called microelectrode recording and microstimulation. It adds time to the operation, but it lets the team confirm the target with the patient’s own brain signals and responses rather than relying on images alone. Our center has three advanced intraoperative electrophysiology systems: Inomed, FHC and Alpha Omega.
Why awake surgery?
MRI shows the anatomy of the target, but every brain is slightly different, and the best spot for stimulation is only a few millimetres across. When the patient is awake, the team can:
- listen to the brain: each region of the brain has a typical electrical “signature”, so the recordings show exactly when the electrode tip enters and leaves the target
- test the effect: small currents through each track show where stimulation acts and how much current can be given before side effects appear
- talk to the patient: the patient reports tingling, muscle pulling, flashes of light or changes in speech, which tell the surgeon how close the track is to neighbouring structures
- choose the best track on each side before the permanent electrode is placed
In dystonia, the benefit of stimulation usually builds over weeks and months, so the main aim of testing during surgery is to map the target precisely and find the margin before side effects appear.
Step by step: microelectrode recording and microstimulation
- Local anesthesia and frameThe scalp is numbed and a stereotactic frame is fixed. The brain itself has no pain receptors.
- Planned tracksOn 3 Tesla MRI, a central track and neighbouring parallel tracks are planned for each side.
- RecordingOn average three test microelectrodes are advanced millimetre by millimetre on each side, recording brain-cell activity along the way.
- Test stimulationSmall test currents are given through each track, checking effect and side-effect thresholds with the patient awake.
- Choosing the best positionThe results of all tracks are compared and the permanent electrode is placed in the best one.
- Repeat on the other sideThe same process is done for the second side.
- StimulatorThe electrode position is confirmed and the stimulator is implanted below the collarbone.
Our electrophysiology systems
Our center has three of the most advanced intraoperative electrophysiology systems: Inomed, FHC and Alpha Omega. They record the activity of single brain cells through the test microelectrodes and deliver precisely controlled test currents. Having three systems gives the team the right tool for each case and a backup in every operation.
When is the operation done under general anesthesia?
- When dystonia is so severe that the patient cannot lie still safely while awake
- When the patient does not wish to be awake
- When there is a medical reason that makes awake surgery difficult
Under general anesthesia, the team still uses 3 Tesla MRI planning and electrophysiological recording to confirm the target, and CT to check the final position.
What does the patient feel?
- The frame and the small openings are done under local anesthesia, so they are not painful
- During recording, patients usually feel nothing; they may hear the crackling sound of brain-cell activity from the recording system
- During test stimulation, patients may feel brief tingling or muscle pulling, which stops as soon as the current is switched off
- The team talks with the patient throughout and explains each step
More on DBS surgery and recovery and on what makes DBS successful.
Frequently asked questions
Is awake DBS surgery painful?
No. The scalp is numbed with local anesthesia and the brain does not feel pain. Test stimulation can cause brief tingling or muscle pulling, which stops immediately.
Why not place the electrode directly?
Testing several tracks lets the team confirm the best position using the patient’s own brain signals and responses, rather than relying on images alone.
How many test electrodes are used?
On average three on each side of the brain.
Can I have DBS for dystonia under general anesthesia?
Yes, if your symptoms are very severe or you do not wish to be awake. Prof. YILMAZ prefers to perform DBS with the patient awake, so that microelectrode recording and microstimulation can identify the best electrode position for each patient. When dystonia is very severe, or when a patient does not wish to be awake, the operation is performed under general anesthesia.