Brain

Deep Brain Stimulation (DBS)

More than 150,000 patients have undergone DBS. The present day techniques make it a very safe procedure.

Life Style Modification /After DBS Care

Treatment of movement disorders not only involves medication and surgery but also includes diet, exercise, support of family and friends as well as a healthy life style.

Patients are advised to have positive and hopeful attitude, do regular exercise, yoga and meditation to improve their quality of life and lessen depression and anxious moods.

Patients should be informed to take normal healthy diet which promotes overall well-being. They should also be encouraged to take low protein, fibre-rich diet with avoidance of milk & milk products.

Drinking plenty of fluids should be encouraged which helps in alleviating constipation. Connecting with people who are supportive can be very helpful in coping stress. Communicating with support groups offer a secured place to express your feelings and concerns as well as to get valuable information regarding your queries.

Deep Brain Stimulation surgery gives the patients a better quality of life, makes them independent and enables them to do things, they would not otherwise be able to do without active support from others.

The patients with Internal Pulse Generator (IPG) (also called as battery) implanted inside their body should take the following precautions during their lifetime:

There is a possibility of electromagnetic interference (EMI) of IPG with following commercial devices and equipments, so their use should be avoided:

Electrical equipments e.g. arc welders

Induction furnaces and resistant welders

Communication equipments like microwave transmitters & power amplifiers

High-power amateur transmitters & high voltage power lines

Metal detectors and screening devices at airports & railway stations.

Following sources of EMI at home or occupational environment unlikely to interfere with IPG functioning include the following:

Home appliances that are properly grounded without open electrical circuit and in good working condition.

Cell phones – as per recommendation, it should not be kept in the shirt pocket over the area of pacemaker.

Electrical or fire cremation should not be performed with the IPG in-situ as there is risk of explosion. IPG should be removed and safely disposed of before the rituals.

[All explanted components should be returned to respective production company (Medtronic/ Boston scientific) for analysis and their safe disposal].

Diathermy e.g. surgical monopolar cautery, diathermy used for dental procedure etc. should not be used in patients with DBS implants in situ during surgical procedures. If it’s absolutely required, then only bipolar diathermy can be used.

The DBS neurostimulator system may influence the function of other implanted devices, such as cardiac pacemakers and implantable defibrillators in patients.

Possible effects include inappropriate devices responses as they cross talk.

If the patient requires concurrent implantable DBS pacemaker system and cardiac defibrillator therapy, careful programming of each system is required to optimize the benefit from each device.

IPG can also interfere with ECG tracing & therefore repositioning the ECG leads away from the pacemaker can avoid this interference. External defibrillation can also damage the Neurostimulator.

These precautions should be followed to minimize current flowing through the neurostimulator and lead-extension system during external defibrillation:

Position defibrillation paddles away from the neurostimulator as much possible.

Always position defibrillation paddles perpendicular to the implanted DBS neurostimulator – lead system.

The lowest clinically appropriate energy output (watt seconds) from the defibrillator should be used.

Neuro-stimulation system function should be checked after any external defibrillation.

Proper shielding of the DBS pacemaker system is required to exclude it from the field of radiation.

The beam of ultrasonic devices like Electrohydraulic Lithotripter should not be focused near the stimulator if it’s use is mandatorily required.

Patients with an implanted DBS pacemaker system should not be exposed to the strong electromagnetic fields produced by magnetic resonance imaging (MRI). Use of MRI may potentially alter the neurostimulator settings, activate/deactivate the device or induce high voltages in the neurostimulator which is transmitted through the lead to the electrode contact points.

An induced high voltage from the neurostimulator transmitting to the lead can cause uncomfortable “jolting,” or “shocking” levels of stimulation. Additionally, MRI may dislodge the electrode contact points or can heat the lead.

All of the above effects are potentially injurious to the patient. Patients exposed to the electromagnetic fields generated from an MRI machine should be closely monitored, and programmed DBS parameters are verified upon completion of MRI.

However, a study published by Tronnier et al. in 1999 on heating effects of 1.5T MRI on IPG device and leads has established the fact that, there is insignificant heat induction due to MRI scanning which did not appear to harm patients.

MRI Guidelines for Pacemaker: Medtronic & Vercise (Boston Scientific)

Usually MRI is considered to be contraindicated in the patients with implanted neuro-stimulator. However, in cases, where MRI is needed, Medtronic has issued the following guidelines for performing MRI scan in patients with implanted neurostimulator.

Different MRI scanner interact differently with various neuro-stimulators. A brief guideline for each device and its interaction with groups of neuro-stimulators is described below.

These guidelines are only for information but the requirements for different pacemakers are different; therefore, before proceeding for MRI scan you must check with your doctor.

Medtronic DBS Systems

Impedance measurements should be performed on implanted neurostimulation systems to verify system integrity & therapy should be turned off prior to MRI scan.

Eligible for MRI scans of whole body: patients must be scanned under the following conditions:

  1. MRI scanner must be of 1.5-tesla (T) horizontal closed bore.
  2. Maximum spatial gradient of the MRI machine must be of 19 T/m (1900 gauss/cm).
  3. RF transmit/receive body coil (built-in) or RF transmit/receive head coil should be available.
  4. Maximum RF power of 2.0 µT B1+rms (B1+ root mean squared) is allowed.
  5. If B1+rms is not available, a maximum RF power of 0.1 W/kg (0.05 W/lb) whole body and head SAR (specific absorption rate) should be used.
  6. Gradient slew rate should be limited to 200 T/m/s

Eligible for MRI scans of the head only: patients must be scanned under the following conditions:

  1. MRI scanner should be 1.5-tesla (T) horizontal closed bore
  2. RF transmit/receive head coil only should be available
  3. Maximum RF power of 0.1 W/kg (0.05 W/lb) head SAR is allowed.
  4. Gradient slew rate should be limited to 200 T/m/s

Contraindication

MRI procedures using a full body transmit radio-frequency (RF) coil, a receive-only head coil, or a head transmit coil that extends over the chest area is contraindicated in patients with the following implanted Medtronic DBS systems or system components:

  1. Soletra Model 7426 Neurostimulator
  2. Kinetra Model 7428 Neurostimulator
  3. Activa SC Model 37602 Neurostimulator
  4. Model 64001 and Model 64002 pocket adaptors implanted with any DBS system

After the MRI scan is over, the patient must see the clinician managing the patient’s neurostimulation system to have the therapy turned back on and program therapy back to the original settings.

For details, please refer to MRI guidelines for Medtronic deep brain stimulation systems.

MRI guidelines for Boston Scientific Deep Brain Stimulation System

  1. MRI magnet strength should of 1.5 tesla only in a horizontal closed bore system
  2. Gradient system of maximum gradient slew rate per axis ≤200T/m/s
  3. Maximum spatial field gradient ≤40T/m(4000gauss/cm)
  4. Cumulative active scan time with RF on should be ≤30 minutes
  5. Stimulator should be fully charged before MRI scan.
  6. MRI mode should be turned on in the stimulator before scanning (stimulation is automatically turned off)

After MRI scan is over & the patient is exited from the scanner room, patient’s physician is contacted for disabling the MRI mode, enabling the stimulation turned on & also to rule out any adverse effect.