Implantable neurostimulators

Main article: Neurostimulators

How implantable neurostimulators work

In a conversation with Zdrav.Expert, the neurosurgeon of the Kuzbass Regional Children's Clinical Hospital named after Yu. A. Atamanov Eduard  Froshkaiser in November 2021 said that implantable neurostimulators can help in cases where conservative treatment of some neurological diseases stumbles - there is either no effect from the treatment, or there is, but to a minimum extent. Neurostimulators are used for deep brain stimulation (GSM).

The essence of the operation is as follows: electrodes are introduced into the deep parts of the brain, to which an implantable neurostimulator is connected. With the help of electrical stimuli, each millisecond is stimulated by damaged areas responsible for movements.

Movement-related symptoms of Parkinson's disease and other neurological diseases are caused by disorganization of electrical signals in areas of the brain that control movement. If successful, GSM interrupts irregular signals that cause tremors and other symptoms of movement. After a series of tests determining the optimal place of installation, neurosurgeons implant one or more wires inside the brain. The wires are connected by an insulated cable with a very small neurostimulator implanted under the collarbone, like a pacemaker. Continuous pulses of electric current from the neurostimulator pass through the wires and enter the brain. A few weeks after the installation of the neurostimulator, the doctor programs it to send an electric signal. This programming process can take more than one visit over several weeks or months to ensure that the current is properly tuned and produces effective results per patient. When adjusting the device, the doctor seeks to find the optimal balance between improving symptom control and limiting side effects.

Physicians may use stimulation to treat motor disorders or neuropsychiatric diseases when medications have become less effective or their side effects interfere with daily human activity. According to Froshkaiser, the effectiveness of the operation reaches 97%, which is the best result among all treatments.

Cons - change the stimulant once every 3-7 years; "gentle" electrodes can break and need to be reinstalled. Well, the main minus is expensive. Not every hospital can afford such installations, "he said.

Movement-related symptoms of Parkinson's disease and other neurological diseases are caused by disorganization of electrical signals in areas of the brain that control movement. If successful, GSM interrupts irregular signals that cause tremors and other symptoms of movement.

How is the implant surgery going

Neurostimulator implantation surgery is performed as follows:

• Implantation of a conductor, a person removes clothes, jewelry or other objects that can interfere with the procedure.

• After shaving a small amount of hair behind the hair growth line, the surgical team introduces local anesthesia into the scalp to install the head frame.

• The head frame or halo is attached to the skull with screws and remains in place throughout the procedure to keep the head in the correct position.

• The team then uses computer or magnetic resonance imaging (MRI) to pinpoint the target location in the brain where the conductor will be inserted.

• After the administration of painkillers, the neurosurgeon drills a small hole in the skull to insert a conductor.

• The team records the process of advancing the wire through brain tissue to make sure it is placed accurately. During recording, the patient may be asked to move his face, hand or foot at a certain time.

• After the conductor is installed, it is connected to an external neurostimulator. Electrical stimulation, conducted through a conductor for a short period of time, helps doctors determine whether symptoms improve or side effects, such as muscle contractions or visual events, appear.

• An extension wire is attached to the wire, which is placed under the scalp and connects the wire to the neurostimulator.

• The hole in the skull is closed with a plastic plug and sutures are applied.

After surgery for deep brain stimulation:

• In the hospital. As a rule, the hospital stay after GSM surgery is 24 hours, but it may be longer, depending on how quickly the patient recovers and is ready to go home. The doctor will visit the patient, make sure that he is ready to leave, and give instructions for home care.

• At home. At home, it is important to monitor the cleanliness and dryness of cuts. The doctor will tell the patient how to take a bath while the surgery site heals. If there are stitches, they will be removed during a subsequent visit to the office. The adhesive strips, if any, should be kept dry and usually fall off for several days. The patient will be given a magnet that can be used to turn the neurostimulator on or off under conditions prescribed by the doctor.

People who have undergone GSM surgery should:

• Always carry with you an identity card, which indicates that they have a neurostimulator GSM. In addition, they may wear a medical identification bracelet indicating this information.

• People with a neurostimulator should report this to airport security officers before passing through detectors. Many detectors at airports are safe for pacemakers, but a small amount of metal in the neurostimulator can cause alarm. Patients selected for additional testing with hand-held detectors should be politely reminded by the examiners that the detector should not be kept over the neurostimulator for longer than a few seconds, as these devices contain magnets that may affect the neurostimulator's operation or programming.

• Patients with conductors and neurostimulators cannot undergo some magnetic resonance imaging (MRI) procedures. Before any type of MRI, patients should necessarily consult a doctor, although under certain circumstances, GSM may be compatible with MRI. They should avoid places with large magnetic fields, such as electric generators and automobile landfills, where large magnets are used.

• Patients who have undergone GSM surgery should avoid using heat in physical therapy to treat muscles.

• They should also avoid high voltage or radar equipment such as radio or television transmitters, electric arc welders, high voltage wires, radar installations or melting furnaces.

• If the patient has to undergo surgery, he must inform his surgeon in advance of the presence of a neurostimulator. It is important to ask advice for special precautions before and during surgery, since equipment such as an electric cauterizer that controls bleeding can interfere with the neurostimulator.

• When participating in physical, recreational or sports activities, patients should protect the neurostimulator area from injuries. A blow to the chest near the pacemaker can affect his work and serve as an occasion to see a doctor.

Neurostimulator Programming

After installing the GSM conductors and neurostimulator, the patient returns to the doctor to program the neurostimulator for optimal electrical stimulation. Programming usually begins a few weeks after the surgery procedure, although some doctors activate the neurostimulator before the patient is discharged from the hospital after surgery. Programming takes time, and it may take several visits to adjust the neurostimulator parameters. At the same time, doctors are working on the patient's drugs and their dosages so that the drugs work effectively together with electrical stimulation to control symptoms.

Even after adjustment, the patient will need to periodically come for examinations. The doctor determines the frequency of subsequent visits depending on the specific situation of each patient. The neurostimulator operates from a battery, the service life of which is usually from three to five years. When the battery begins to wear out, doctors can replace the neurostimulator during the outpatient procedure. There are also rechargeable neurostimulators that work longer but require regular recharging.

To whom neurostimulators are shown and contraindicated

Neurostimulators are shown for use in humans having the following abnormalities:

• Parkinson's disease;
• Essential tremor;
• Dystonia;
• Psychiatric illnesses.

• Suppression of pain syndrome - the method of neurostimulation for 2017 is considered the most effective way to suppress chronic pain syndrome. Pain is just a signal that is transmitted through nerves from a problem area to the brain. Pain is just information to the brain that there is a malfunction in the body and it needs to be eliminated. But this "mere information" can make a person's life unbearable, especially when it comes to chronic pain.

Neurostimulators resemble pacemakers in shape: a metal body is implanted under the skin, and electrodes are introduced into the brain or spinal cord. This small device is implanted under the skin in the area of ​ ​ the lower back and sends weak electrical signals to the spinal cord through the electrodes. These signals intercept pain impulses and a person senses a pleasant tickling instead of pain.

Spinal neurostimulation is carried out using a small electric pulse generator device that is implanted into the spinal cord region. The whole system is not visible externally, as it is under the skin and does not constrain the patient's movements. Before setting up a permanent neurostimulating system, test stimulation is necessarily carried out, in which the doctor and the patient himself can verify the effectiveness of stimulation with the help of an external test electrode. If at this stage a positive effect is achieved, then a neurostimulator is implanted.

Who falls into the categories of unwanted candidates for deep brain stimulation with the following diagnoses:

• Difficulties with balance, walking or fading;
• The main symptom is difficult speech;
• Constant confusion and problems with memory and thinking;
• A psychiatric condition such as depression or anxiety that has not improved or stabilized with other treatment;
• Another condition that increases the risk of complications of surgery.

Some of these factors may be treatable. Having one or more symptoms does not eliminate the possibility of GSM surgery at all, but the doctor may recommend more aggressive therapy aimed at solving these problems before the operation.

Risks and side effects from the use of neurostimulators

Although deep brain stimulation with neurostimulators is generally thought to be associated with low risk, any type of surgery is fraught with complications. In addition, brain stimulation itself can cause side effects. Deep brain stimulation involves creating small holes in the skull for implanting electrodes into brain tissue, as well as performing an operation to implant a device containing batteries under the skin in the chest. Complications of surgery may include:

• Incorrect pin placement;
• Bleeding in the brain;
• Stroke;
• Infectious disease;
• Breathing problems;
• Nausea;
• Heart problems.
• Numbness or tingling;
• Headache;
• Difficulties in concentrating attention;
• Problems with speech;
• Balance problems;
• Frivolity;
• Vision problems, such as twofold eyes;
• Unwanted mood changes such as anger and depression.
• Temporary pain and swelling at the site of implantation.

Chronicle of Technology Development

2018: A brain implant directed a car into a crowd of people

In April 2018, The Conversion published an article, the authors of which ask whether it is possible to accuse a person of a crime whose illegal actions were committed under the influence of a neurostimulator.

In 2018, deep brain stimulation is increasingly being used - a procedure in which an implant sends electrical pulses to target neurons to change their activity. These brain implants are designed to treat neural dysfunction, but can have an undesirable effect on human perception and behavior. 

It's not me, it's my brain implant. The driver explained why he drove into a crowd of people

Journalists told the story when a woman drove into a bus stop with a large number of people. As a result of the accident, they were injured, and the culprit said that she did not see a stop when she received an electronic impulse from a brain implant intended for the treatment of Parkinson's disease. According to the motorist, the brain received a signal to move towards a stop due to a malfunction of the implant. How this story ended is unknown.

The conditions under which individuals should be considered legally and morally responsible for their actions are stipulated by law. However, can a person who acts under the influence of a brain implant be considered responsible for his behavior? What happens if one day the driver drives into a crowd of people at a stop, and later declares that he did it under the influence of a pulse from a faulty device - who should be considered responsible in this situation? The decision of the court will depend on whether such an offender will be criminally liable and will have to undergo treatment.

In addition, questions arise about the responsibility of manufacturers, researchers and developers of such technologies, as well as about the negligence of medical specialists who implant and program the device. Even if more than one party was responsible, the question remained as to how to allocate that responsibility. At the same time, the possibility of criminal interference in the operation of implants is not excluded. 

The publication also says that one of the patients treated for severe obsessive compulsive disorder suddenly discovered that he loved Johnny Cash's music; when the implant was turned off, the patient returned to his usual musical preferences. Another patient, to whom deep brain stimulation was carried out to clarify the cause of epileptic seizures, stated that his doctors had turned into cooks with aprons. In both cases, deep stimulation changed perceptions, raising a number of issues for discussion.^[1]

2017: Operations in the ZITO named after Priorov

On June 29, 2017, at the Central Research Institute of Traumatology and Orthopedics (CITO) named after N. N. Priorov, an operation was carried out to implant a spinal neurostimulator on Medtronic equipment. Neurostimulator implantation operations have been carried out in CITO since 2017. The cost of the operation at this time is about 1 million 300 thousand rubles. Of these, about a million is the cost of a neurostimulator and 300 thousand is the cost of implantation. However, for citizens of the Russian Federation, these operations are carried out free of charge within the framework of quotas for High-Tech Medical Care (VMP). In 2017, CITO allocated 50 quotas for this type of operation, it is possible that their number will be increased. The need for such operations is an order of magnitude higher.

The uniqueness of Medtronic equipment is that the test electrode can be connected to a permanent neurostimulator without extracting from the spinal cord. This allows you to reduce the time of surgery and make the surgeon work more comfortable, and patients receive high-quality high-tech care. The essence of the method is that the neurostimulator generates electrical pulses that seem to replace signals about pain and thus actually deceive the nervous system. As a result, instead of acute pain, the patient experiences mild tingling, trembling or other non-painful symptoms.

The operation was carried out by a doctor of the highest category, Professor Alexander Evgenievich Yakovlev. He successfully treats pain syndromes, motor disorders, acute cerebral circulation disorders and their consequences for more than 20 years, performs neurostimulation operations for more than 10 years: he performed more than 20,000 operations, of which more than 3,000 for the installation of neurostimulation systems and the delivery of drugs. Yakovlev lived for many years in the United States, taught at the Medical University of Wisconsin. He is a member of the American Society for Pain Management, the American and International Society for Neuromodulation (Functional Neurosurgery), and the American Spinal Society.

The patient is a 49-year-old man. In 2009, as a result of an unsuccessful fall with a parachute, he received an injury to the spine, ribs and thigh. Since that time, he has been in burning pain. In addition, he lost the ability to move on his feet and used a wheelchair. According to Alexander Yakovlev, neurostimulation will not only relieve pain syndrome, but can also return the patient's ability to walk^[2].

2016: Ukraine is asked to provide funds in the budget for the installation of neurostimulation systems for 19 patients

In October 2016, it became known that "people on batteries" - patients in Ukraine suffering from orphan disease "torsion dystonia," are asked to provide for the allocation of UAH 9.1 million in the state budget for 2017 to install neurostimulation systems for 19 patients and replace batteries for these systems. More details here.

2015: Neurostimulators began to be used to treat obesity

Obesity is a dangerous disease, so in advanced cases, the patient undergoes gastric bypass surgery so that he becomes smaller and stops sending "I want to eat" signals to the brain. However, if it's only about signals, then why torment the stomach? After all, doctors have already learned to fight with nerve signals with the help of neurostimulators. The company EnteroMedics has already received American and European certification for the use of its Maestro neurostimulator for the treatment of obesity. The electrodes of the neurostimulator are connected to the stomach wall and send impulses to the vagus nerve, which allows blocking signals from the stomach to the brain and leads to depression of appetite.

2014: Pain-sized neurostimulator certified to eliminate back pain

An ordinary neurostimulator is a box the size of a pudrenica. It is quite small, but still I don't really want to implant it under the skin. The American company Stimwave Technologies has created (and has already received FDA certification) a Stimwave Freedom neurostimulator, which fits on the tip of the finger and is absolutely not felt after implantation. In addition, it is injected directly into the desired section of the spinal cord and eliminates the need to pull electrodes from the lower back (where a standard neurostimulator is usually located) through the spine.

Like a conventional neurostimulator, Stimwave Freedom connects to nerve fibers and suppresses pain signals that go to the brain^[3].

2013: EU allows use of Libra and Brio brain neurostimulators to treat acute dystonia

Just as a pacemaker helps a patient to heart shrink rhythmically, an electrical brain stimulator helps the brain patient rhythmically perform logical operations and control the body. This is a small implant that sends weak electrical vibrations through the electrode to the right area of ​ ​ the brain. Electric stimulators are already used to treat epilepsy, depression, Parkinson's disease. Now the European Commission has given the go-ahead to St. Jude Medical on the use of its Libra and Brio brain neurostimulators to treat acute dystonia. Acute dystonia is a syndrome characterized by involuntary movements with the formation of pathological poses. The implant stimulates the brain region responsible for the motility and suppresses the messy signals generated by the diseased brain that cause muscle dystonia.

2006: EU allows Eon implantable neurostimulator

In 2006, the American company St. Jude Medical received the European Commission's welcome to use the implantable neurostimulator Eon to eliminate chronic pain.

Like a pacemaker, Eon (# 2 in the picture) is installed under the skin in the lumbar region, and its electrodes are injected into various parts of the spinal cord (since it is through the spinal cord that pain signals from the body pass). The neurostimulator generates weak electrical pulses that plug the pain signals. At the same time, instead of pain, a person feels a pleasant massage.

Eon is programmed for each patient separately (since the profile of pain pulses may be different). For reprogramming, data removal, switching on/off and recharging the neurostimulator, a special control panel is used that connects to the implant through the skin (without the need for surgery).

Of course, this device eliminates not the cause of pain, but the pain itself. The cause of pain - you need to treat separately.

Notes