DBS PROCESS

Before surgery

If DBS is being considered, a workup is needed to assess whether your condition will respond and if so, which brain target to choose. The first step is a consultation with the DBS neurologist.  Depending on your condition, you may then need to see a psychiatrist or neuro-psychologist to assess mood and cognition. Patients with Parkinson’s disease will have their movement graded by a specialist nurse or physiotherapist, both off and on medication. If the assessment suggests that you are suitable for DBS and you wish to proceed, you will then see the neurosurgeon.
DBS surgery is elective, so can be deferred until you are ready – although the exact date depends on theatre availability.  In the month before surgery, you will have a special MRI brain scan.

Before surgery, you will receive education regarding the surgery and living with the implanted hardware. You will need to choose between two types of battery– a ‘primary cell’ or rechargeable. Primary cell batteries are larger and need replacement around every 3-4 years (under local or general anaesthetic). Rechargeable batteries are smaller, need recharging for at least an hour each week (this varies) and last up to 9 years. 

Surgery

You are usually admitted to hospital the day before surgery. Many patients elect to shave their entire head before admission (otherwise the surgeon will shave the front of the head only in theatre). On the morning of surgery, any medications for tremor or Parkinson’s disease are withheld.

In theatre, the neurosurgeon physically performs the procedure and the neurologist guides the electrodes into the brain target (using brain scans and by assessing brain signals and the effects of stimulation).

There are two parts to the procedure (taking around 3-4 hours in total). We usually perform these consecutively on the same day:

  1. Electrode implantation: Patients with Parkinson’s disease and Essential tremor are kept awake with local anaesthetic and light sedation. Patients with Dystonia and Epilepsy are usually kept asleep (general anaesthetic). A ‘frame’ is attached to the head followed by a CT scan. A skin and scalp incision is made. A small hole is drilled through the skull bone. A tiny test wire (‘microelectrode’) is passed into the brain. Brain signals are recorded. Stimulation is applied and any improvement and side effects are assessed. Based on this information, the microelectrode may be shifted. When the target has been identified, the microelectrode is replaced with the permanent electrode under X-Ray guidance. The procedure is then repeated on the other side of the brain.

  2. Cables and Battery:  Patients who have been awake are given a general anaesthetic. The head frame is removed. The battery (usually sited beneath the collar bone) and connecting cables (running between the brain electrode and battery) are implanted under the skin.

Typically, patients are able to walk independently the day after surgery. Within a few days, you have another CT scan to confirm electrode location. Most patients are discharged home after 4-7 days.

After surgery

Stimulation and medication adjustments

In the first weeks postoperatively, control of the underlying condition can fluctuate whilst medication and stimulation are adjusted.  In this period, you may need to see the neurologist frequently (e.g. every 1-2 weeks).

Even without stimulation, movement often improves due to ‘stun effect’. ‘Stun effect’ refers to temporary swelling around the freshly implanted electrodes that reduces abnormal brain signals. Stun effect peaks around day 3 then subsides over the following weeks. Because of this, stimulation is often started at a low level then slowly increased. With stun effect and stimulation, medication for Parkinson’s disease is usually decreased.

For most patients, the bulk of the adjustments are over by about 4-6 weeks. However further adjustments may be needed over time. Fine tuning stimulation can be quite tricky and even require a further hospital admission.

You are given your own personal DBS controller (about the size of a computer mouse) which allows you to check battery status and turn stimulation off and on. Occasionally, patients are given the capability to adjust their own DBS (within certain limits).

Recovery and resuming normal activities

This varies from person to person. Guidelines recommend no driving for 6 weeks. This is also a useful ‘rule of thumb’ for other activities such as return to work and other responsibilities. Like other types of neurosurgery, patients can feel that their intellectual functioning, particularly attention span, is reduced for several weeks postoperatively. We therefore suggest deferring any major decisions until this recovers.

There are some long term precautions when living with DBS systems. For example, avoiding heavy contact sports (e.g. boxing), avoiding routine MRI (MRI is possible under special conditions only) and advising surgeons and dentists of your ‘pacemaker’. 

The DBS Risks and side effects