Except in rare circumstances, the SydneyDBS team performs DBS surgery with patients under light sedation only. This is to allow electrical recording and test stimulation to be performed during the operation itself. Brain activity mapping and effects of test stimulation are two important means of confirming surgical accuracy and are best performed when patients are awake. The use of light sedation makes it possible for patients to be briefly woken up for these important stages of the operation.
Patients understandably find the concept of awake surgery to be frightening. Awake surgery is well established in Neurosurgery. Our Neuro-Anaesthetists, Dr Purcell and Dr Donnelley are expert in managing sedation and pain relief, through this part of the operation. Dr George Fracchia, the SydneyDBS surgical assistant provides reassurance and psychological support through the procedure, further assisting the tolerability of this type of surgery.
Once surgical planning is completed, Dr Cook determines the position of the scalp incision, programs the Stereotactic frame, and drills the burr hole through the skull.
This hole made in the skull is about the size of a 10cm piece. A tiny hole is then made in the lining of the Brain allowing passage of the testing microelectrode.
This electrode has dual functionality, allowing direct recording of Brain activity as well as test electrical stimulation. Dr Cook utilises a Microdrive mounted on the sterotactic frame to implant this electrode.
Dr Cook and Dr Silberstein analyse recording from the microelectrode during its passage through the brain.
Subsequently, intra-operative test stimulation is performed. Here the thresholds to clinical benefit and stimulation induced side effects are assessed by Dr Silberstein (below). These findings assist in confirming surgical accuracy.
Intra-operative Xray is the third instrument to confirm surgical targeting. Once satisfactory, the testing microelectrode is replaced with the permanent stimulating electrode. This is attached to the skull using a customising locking system.
Deep Brain Stimulation surgery is most commonly performed on both sides of the brain. The procedure for implanting the other side of the brain is identical.
The scalp wound is then closed, and the patient transferred to recovery whilst the Operating Theatre is prepared for stimulator battery implantation.