Stereotactic surgery
In 1947 the first stereotactic frame was used for human operations. This three dimensional frame fits around the head to hold it in place and guide the surgeon to exactly the right point for surgery. Accuracy is key to neurosurgery and modern computer technology, together with the continued use of the stereotactic frame, allows the surgeon to be precise.
Areas of the brain targeted
Which part of the brain the surgeon targets will be determined by the symptoms that surgery aims to most improve: certain sites in the brain seem to help with specific symptoms, for example:
- the thalamus - for treating drug-resistant tremor
- the globus pallidum internus (GPi), a part of the globus pallidus - for treating stiffness, dyskinesia and akinesia, dystonia and pain
- the subthalamic nucleus (STN) – this seems to be the site that helps most symptoms so tends to be more favoured. It has been estimated that 70-80% of those who have surgery in this area will benefit.
The main surgical procedures
- deep brain stimulation (DBS) uses implanted electrodes to stimulate either the STN or the GPi areas of the brain. The electrical stimulation produced by these electrodes disrupts the abnormal brain activity causing movement problems, and so improves the main motor symptoms. The stimulator can be adjusted or switched off as necessary. This is the most commonly used procedure today
- lesioning delivers an electrical current to a targeted area of the brain, which heats and destroys or ‘lesions’ that area, usually around the size of a pea. This is not reversible and its effects cannot be switched on and off in the way that DBS can be, so it is not commonly used today
- gamma knife surgery uses gamma radiation on damaged brain tissue, but again this procedure is not reversible and cannot be adjusted in the same way as DBS so is rarely used today.
Other surgical techniques
Other surgical techniques currently being researched are:
