WHAT IS DEEP BRAIN SIMULATION (DBS)?
DBS refers to high frequency stimulation of deep neuroanatomical targets within the brain to improve neurological function in a variety of neurological disorders. To allow this an appropriately trained neurosurgeon places electrodes very accurately within certain targeted collections of nerve cells or nuclei deep within the brain using a combination of computerised targeting and physiological confirmation of the intracranial target. These are connected to an internal pulse generator device under the skin which delivers current to the electrodes and requires periodic programming. The high frequency stimulation may be used to control the unwanted motor symptoms of conditions like Parkinson’s Disease, essential tremor or dystonia including tremor, rigidity, dyskinesia and bradykinesia. DBS has been used for twenty years around the world, is effective but, unfortunately, is not a cure for these neurological conditions. To see whether you are potentially eligible for DBS speak to your neurologist.
IS DBS BETTER THAN LESIONAL SURGERY?
DBS originally evolved from surgery designed to make highly accurate permanent lesions within the brain to control movement disorders e.g. thalamotomy or pallidotomy. The potential advantages of lesional surgery is that it is generally quick, inexpensive, the results permanent and there is no need for placement of electrodes in the brain, programming or follow up care. The potential advantages of DBS include the reversibility of the effects of stimulation and that bilateral electrodes can be placed unlike lesional surgery. Which procedure is better depends upon each patient’s unique situation.
WHAT IS RADIOSURGERY?
Radiosurgery is a radiotherapy technique which involves the delivery of a single highly focused dose of radiotherapy to an intracranial target. It was originally developed in the 1950s by Professor Lars Leksell in Sweden and is most commonly delivered using either x rays from a linear accelerator (LINAC) or gamma rays from a cobalt source (GammaKnife). LINAC is the most commonly available technique in Australia and Europe while GammaKnife predominates in the USA. The procedure is performed as a day procedure and involves application of a special localising head frame, CT or MRI imaging to outline the target, treatment planning and dose calculation and delivery of the radiotherapy. Radiosurgery is done jointly by a neurosurgeon and radiation oncologist working as a team. Radiosurgery may be used to successfully treat brain metastases, brain vascular malformations, some benign intracranial tumours e.g. accoustic neuroma, trigeminal neuralgia and some movement disorders.
WHAT IS SPINAL CORD SIMULATION?
Spinal cord or dorsal column stimulation is a technique which involves the use of a electricity and the resultant electromagnetic field in leads which are surgically placed over the spinal cord to relieve pain in the limbs and lesser extent in the back. The leads may be placed either through the skin (percutaneously) or via an open spine operation using x ray guidance. A trial of stimulation is often performed first to ensure adequate coverage of the painful area and to test the response (degree of pain relief) to stimulation. If the stimulation is helpful, sometimes defined as a greater than 50% improvement in the pain, the leads can be connected to an internal pulse generator (like a pacemaker), which can be externally programmed. Spinal cord stimulation has been used successfully for over 30 years.