Deep Brain Stimulation for Parkinson's: Timing and Cost

Deep brain stimulation (DBS) for Parkinson's disease is the next step once medication stops working well enough, with rising doses, side effects or a waning effect. In the experience of Dr. Anil Kumar Kansal, Vice Chairman & HOD - Neuro Surgery & Neuro Spine, BLK-Max Super Speciality Hospital, New Delhi, India, that point usually comes four to five years after diagnosis, and DBS there costs about USD 30,000 to 35,000.

DBS belongs to functional neurosurgery, which treats conditions whose main burden is lost function rather than a mass to be removed: Parkinson's disease, dystonia, drug-resistant epilepsy and the facial pain of trigeminal neuralgia. They can take away a patient's ability to walk, eat or carry out ordinary daily activities. Dr. Kansal sets out a consistent principle: medication comes first, and surgery enters at a defined point, when the drugs stop working well enough or their side effects become the problem.

Why Parkinson's disease may need surgery

Parkinson's disease may need surgery because medication, effective at first, eventually stops delivering an acceptable balance of benefit and side effects. Dr. Kansal describes Parkinson's disease as a highly disabling condition. Patients may be unable to walk or to feed themselves, and involuntary movements interfere even with the act of eating.

Treatment begins with medication. His practice is to start at a low dose and increase it gradually to control the disease and its symptoms. That works for a period. Over time, however, one of three things happens: the dose required becomes too high, side effects start to appear, or the medication's effect wanes.

When to have deep brain stimulation for Parkinson's

That point, in Dr. Kansal's experience, usually arrives around four to five years after diagnosis, and it defines the ideal time for deep brain stimulation (DBS). The purpose of the operation at that stage is to stop the drugs or to reduce them substantially.

The timing logic is worth stating plainly to patients and referring doctors. DBS is not a first-line treatment. It is the next step for a patient whose medication has stopped delivering an acceptable balance of benefit and side effects.

DBS is also used in dystonia.

How DBS electrodes are placed

The target in Parkinson's disease is the subthalamic nucleus, a small structure deep in the brain involved in controlling movement. A stereotactic frame is applied, and the team then confirms the target by three independent methods:

1. Anatomical localisation on imaging.
2. Monitoring the brain's electrical activity, recording its waves to identify the target.
3. Clinical testing on the table. With the electrode in place, the patient is asked to perform movements, and the team checks that the electrode is correctly positioned and is improving them.

The third step makes the patient's own motor response the final confirmation that the electrode is in the right place.

Long-term drawbacks of DBS: battery, hardware and reprogramming

Battery replacement is the main long-term drawback of DBS. Asked in the Live Discussion about the major drawbacks of DBS ten or fifteen years after implantation, Dr. Kansal identified three:

• Battery replacement. This is the main issue. A non-rechargeable battery has to be replaced every few years, with the interval depending largely on the stimulation settings. A rechargeable battery lasts around 15 years.
• Hardware failure. After trauma or another event, an electrode can disconnect, or the electrode itself can fail.
• Reprogramming. A patient's stimulation settings may need adjusting over time, which has traditionally meant frequent visits to the treating centre. Newer devices allow settings to be changed from a mobile phone, a real advantage for international patients who would otherwise travel back for adjustments.

Deep brain stimulation cost and device choice

Dr. Kansal put the cost of DBS at his hospital at around USD 30,000 to 35,000, covering medicines, tests, surgery and the hospital stay. The figure varies with the device, because equipment from different companies is priced differently.

The trade-off between devices maps directly onto the battery issue:

• Non-rechargeable devices cost less, but the battery has to be replaced every few years.
• Rechargeable devices cost somewhat more.
• Newer devices with monitoring features are more expensive still.

His team uses whichever option the patient chooses. For a referring doctor, the practical point is that the lower upfront price of a non-rechargeable system comes with a battery replacement procedure a few years later. Indicative costs for other brain and neurosurgery procedures are listed separately.

Deep brain stimulation vs focused ultrasound

MRI-guided focused ultrasound is now in use for essential tremor and Parkinson's disease. Instead of implanting an electrode, the surgeon uses ultrasound, guided by MRI, to create a focused lesion at the chosen target.

Focused ultrasound creates a permanent lesion and is usually performed on one side of the brain, whereas deep brain stimulation is adjustable and can treat both sides. For that reason DBS remains the most established surgical treatment for advanced Parkinson's disease.

Surgery for drug-resistant epilepsy

For drug-resistant epilepsy, removing a lesion or focus comes first, and stimulation is reserved for patients without one. Dr. Kansal's team does place electrodes for intractable seizures, but not routinely, because in his view other methods are still better. The sequence he follows is:

1. Look for a lesion. If a lesion is found, it is removed.
2. Resective surgery. Medial temporal lobectomy is performed where indicated, and in some patients hemispherectomy.
3. Neuromodulation when no focus is found. If the epilepsy remains uncontrolled and no focus can be identified, there are two options: vagal nerve stimulation, or electrodes placed in the anterior thalamus.

Anterior thalamic stimulation reduces seizure frequency progressively over time: in the pivotal SANTE trial, about two-thirds of patients had at least a 50% reduction in seizures by five years. The ordering is the point: neuromodulation is reserved for patients in whom resection is either not possible or has not worked, because removing a focus remains the more effective approach when one exists.

DBS for psychiatric disorders: a cautious position

Dr. Kansal's team has performed a small number of frontal DBS procedures for psychiatric disorders. The results are variable: in some patients it works and in others it does not.

His caution is explicit. Patients need to understand three things:

• The procedure is not curative.
• It can control symptoms, but the patient will still need medication.
• The results are not 100%.

Trigeminal neuralgia: microvascular decompression

Where a blood vessel compresses the trigeminal nerve, the main sensory nerve of the face, microvascular decompression (MVD) separates the vessel from the nerve. Dr. Kansal's fuller account of trigeminal neuralgia treatment and microvascular decompression is in his separate masterclass guide.

A condition that is not life-threatening but is disabling

Trigeminal neuralgia can be caused by a tumour or by vascular compression of the trigeminal nerve. It is not life-threatening, but the pain is severe and the disability is real. Patients may be unable to carry out their daily activities: brushing the teeth becomes difficult, eating becomes very difficult, and some cannot feed themselves.

The course mirrors that of Parkinson's disease. Initially, drugs and other methods help. Over time, the required doses climb and side effects follow. As Dr. Kansal puts it, the patients who reach his clinic are not happy with their life and not happy with their medicines.

How microvascular decompression is done

Where a blood vessel is compressing the nerve, the treatment is microvascular decompression. The first task is to identify the culprit vessel: the one in conflict with the nerve.

Through a small craniotomy, the cerebellum is gently retracted to reach the fifth cranial nerve. The endoscope can assist with visualisation. Once the vessel compressing the nerve has been identified, it is separated from the nerve and a graft is interposed between them to keep them apart. Shredded Teflon felt is the standard interposition material. Throughout, the team minimises handling of the nerves and surrounding tissue.

Two variations come up in practice:

• More than one vessel. Sometimes several vessels are in contact with the nerve, and all of them must be moved away.
• Circumferential contact. Sometimes the nerve has to be freed from the vessels around its full circumference.

Microvascular decompression results

Dr. Kansal describes the outcomes of microvascular decompression as excellent. Medication can usually be stopped entirely within a few weeks of surgery, and the patient is relieved of the pain.

This is the clearest contrast with the neuromodulation procedures above. DBS for epilepsy or psychiatric disorders controls symptoms and requires continued medication; microvascular decompression removes the cause and allows medication to stop. For a referring doctor, a patient with trigeminal neuralgia whose doses are escalating and whose imaging suggests vascular compression is the patient for whom a surgical opinion is worth seeking.

Medication first, surgery at a defined point

Across Parkinson's disease, epilepsy and trigeminal neuralgia, Dr. Kansal's practice follows the same structure: medication first, a clearly defined trigger for surgery, and honest framing of what surgery can deliver. The stereotactic and imaging tools that make these procedures precise are described in endoscopic brain surgery, from ventriculostomy to colloid cysts, and the outcomes and limits across the field in recent advances in spine and neurosurgery: a complete guide.