The duration of DBS benefit for Parkinson’s disease (PD) varies depending on a variety of factors including age, the nature of Parkinson’s symptoms, duration of PD at the time of surgery, and the presence or absence of other medical problems. Specific information for any given patient can only be determined by a thorough analysis of individual symptoms, which we establish through a surgical work-up process. That said, evidence from a number of long term studies provide a good general idea of the durability of DBS.
DBS related improvements in tremor appear to be life-long. Whilst it can take up to six months to optimise stimulation settings after surgery, the improvements in tremor achieved at six months are generally persistent in the long term.
Improvements in stiffness (rigidity) post DBS are maintained for > 5 years. In fact, control of upper body Parkinson’s symptoms is long lasting (and often life-long) in the majority of patients.
On average, the improvements in walking and balance achieved in the early years post DBS begin to diminish by 5 years. These changes in gait and balance relate to the progression of Parkinson’s disease. Here again, age and disease factors will play a major role. For example, younger patients may maintain gait and balance for more than a decade post DBS, whereas patients who have surgery in their early or mid-seventies, will generally note some change in their walking and balance by five years after surgery.
DBS results in a > 50% reduction in tremor severity in patients with Essential tremor. Surgery is generally considered in Essential tremor when tremor is severe, not responding to medical therapy and interfering with activities of daily living.
Rigorous level 1 evidence studies examining the efficacy of DBS for Dystonia indicate that 50% of patients experience at least 50% improvement. DBS is indicated when Dystonia is severe and refractory to treatment with tablets or botulinum toxin.
There is limited worldwide experience in DBS for Tourette’s syndrome. We have implanted four patients for severe Tourette’s Syndrome, all of whom have experienced a significant reduction in tic severity and frequency.
Most patients with Parkinson’s disease initially experience many years of good symptom control with tablet therapy. After 5-10 years of treatment however, many patients find that the benefits of tablet therapy become inconsistent and unreliable. Less predictable symptom control can sometimes be associated with excessive and involuntary movements termed dyskinesias. It is generally at this stage the next level of therapy termed ‘Advanced therapy’ or ‘Device assisted therapy’ is considered.
There are three forms of advanced therapy available for the management of PD:
Apomorphine: an injectable medication, which can be delivered intermittently or using an injection pump.
Duodopa: A gel formulation delivered directly into the intestine through a feeding tube inserted through the abdominal wall via the stomach.
DBS: A procedure where permanent stimulating electrodes are implanted in the brain and connected under the skin to a battery implanted in the chest or abdominal wall.
All three techniques can be effective in ironing out symptom control and reducing dyskinesia. Often, all three are reasonable options. The choice of therapy is made by the individual.
With comparison to apomorphine and Duo-dopa, DBS has the advantage that all components are implanted under the skin. This leads to considerably lower maintenance demands on patients and their carers, substantially reduced incidence of device related complications and much improved cosmetic outcomes.
DBS was first performed in Australia in 1997 with the assistance of the French Neurosurgeon who developed the procedure, Professor Benabid. DBS became more widely practiced in Australia in the early 2000s. Dr Cook began performing DBS procedures in 2001 with the assistance of Brisbane Neurologist Professor Silburn. Dr Silberstein and Dr Cook have worked together since 2004. Over 2000 DBS procedures have now been performed in Australia.
The hospital admission is usually 10-12 days. Generally patients are admitted at least two days prior to surgery for blood tests, chest xray, ECG and a further MRI scan of the brain which is used for surgical planning.
Patients are generally awake and alert after their surgery. The first night is spent in the Intensive Care Unit for close monitoring and nursing support. Stimulation is generally commenced on the same day as the surgery.
Most patients return to the ward on the first day after their surgery, and are generally out of bed and walking on day 1. Stimulation and medication adjustments are made over the next week to optimise control of Parkinson’s symptoms. Most patients will require further adjustment after discharge. Stable stimulation parameters are usually achieved by six months after surgery.
Almost all patients experience substantial improvement in symptom control by the time they leave hospital. Optimising stimulation and medications after surgery does take time however – usually around 6 months. These changes are managed by a network of Neurologists who have trained with Dr Silberstein and the Sydney DBS surgical team. Most patients require 3-4 outpatient Neurologic reviews in the first six months. Annual or bi-annual review is generally recommended thereafter.
DBS involves the implantation of one of two wires in the brain, which are then routed under the skin to a pacemaker like device implanted in the chest wall or abdomen.
To maximise surgical access, we undertake a full head shave at the time of the operation. Hair of course grows back, but many patients choose to wear a scarf or hat in the early weeks after surgery. Hair dyes can generally be applied from 8 weeks after the operation.
An incision is made across the top of the scalp to allow access to the skull. This is made behind the hairline if possible. The scar from this incision may be visible in the long term in men with male pattern hair loss.
Two small devices secure the brain wire to the skull behind the surgical incision. These can be felt as two small lumps on the top of the skull.
The brain wires are routed under the skin behind the ear and then down the front of the neck. The wires in the neck look like a vein.
The battery pack is implanted through a five to six cm incision on the chest wall or abdomen. Like all surgical incisions, this leaves a scar. In most people this becomes less visible over time.
All of the DBS apparatus is sited under the skin.
In the medium term most patients become unaware of the DBS system.
We generally recommend our patients limit exercise to walking for the first 8 weeks after surgery. After this, there is usually no restriction on returning to all previous exercise and sporting activity (subject to discussion with treating doctors).
The effects of DBS on personality, cognition (thinking) and behaviour have been extensively evaluated in many international studies. Transient or short lived psychologic changes are common in the first month or so after surgery as stimulation and medication are titrated, and patients adjust to their new circumstances. Long term changes in behaviour are very uncommon.
Patients who are interested in pursuing surgery undergo a careful evaluation process that helps to determine the potential benefits and risks in each individual case. Most patients find this process very helpful in determining whether or not to proceed to DBS (for more information on the surgical work up, see question ‘How long is the waiting list for DBS?’).
A number of cost related options are available, which patients may elect depending on their individual circumstances. Cost is generally discussed early in the assessment process with Dr Silberstein. The cost of the surgery depends on a variety of factors including Private Health Insurance cover.
We implant both non-rechargeable and rechargeable batteries.
Non-rechargeable batteries generally need to be changed after ~ 3 years. Rechargeable batteries by contrast, last ~ 9 years but require charging in a seated position for 2-3 hours per week. Battery life can vary between individuals. All patients are encouraged to check their battery monthly to reduce the risk of unexpected battery failure.
All patients who wish to explore further evaluation undergo a surgical work up. This includes baseline MRI scan, evaluation of Parkinson’s symptoms on and off medication by Dr Silberstein, Neuropsychiatric evaluation with Dr Linton Meagher and Surgical Consultation with Dr Cook. For patients who wish to proceed to DBS, surgery can generally be performed within 4 months of the completion of the surgical work-up.
Stem cell technology is growing rapidly. Currently, several international trials are in progress exploring the safety and efficacy of implanting stem cells into deep areas of the brain in patients with Parkinson’s disease.
Earlier stem cell transplantation research in Parkinson’s disease demonstrated mixed results. Overall, these earlier studies failed to show significant improvement across patient groups. Some individual patients did achieve benefit however, spurring further research in the field. This is an exciting space to watch. In the long term, many of the techniques we currently use for the DBS may have a role in stem cell implantation surgery.
Older surgical treatments such as lesioning (deliberately burning or freezing an area of the brain for therapeutic effect) have not precluded patients subsequently undergoing DBS. Similarly, it seems unlikely that DBS will preclude patients benefiting from future therapies. DBS systems can be partially or totally removed if required.
We proudly partner with Parkinson’s NSW and Shake It Up Foundation to ensure communities feel supported throughout their Parkinson’s journey. Every journey is unique to you and your family, and both Parkinson’s NSW and Shake It Up are here to assist you. Throughout the year, both Dr Cook and Dr Silberstein attend community events to give updates and answer questions about new research or treatments. We encourage you to sign up to receive up to date information from both charities about upcoming events, information, research breakthroughs, etc.