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Patient’s

Manual

for Vagus Nerve Stimulation

with the VNS Therapy™ System

April 2002

9. ADVERSE EVENTS

Although some adverse events (complications and side

effects) are associated with vagus nerve stimulation, most

people with the VNS Therapy System consider them to be

minor. If you are considering vagus nerve stimulation, think

carefully about the risks and learn as much as you can about

the treatment. If you have questions, talk to your doctor. Be

sure to ask about other potential risks and side effects

possibly not covered in this manual.

9.1. Complications

Complications related to the VNS Therapy System can result

from the following:

¨ Surgery

¨ Pulse Generator malfunction

¨ Battery depletion

¨ Manipulation of the device through the skin

9.1.1. Surgery

The Pulse Generator is implanted surgically, like a heart

pacemaker, with an additional neck incision for the Lead. All

types of surgery carry some risks. With this type of surgery,

the Pulse Generator and/or Lead can—but rarely do—move or

break out through the skin. In addition, the Lead can break or

become disconnected from the Pulse Generator.

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The surgical complications listed below are sometimes

associated with implantation of the VNS Therapy System.

They may be short term or long term.

¨ Infection

¨ Pain at the incision site

¨ Tissue reactions, such as inflammation and skin irritation

¨ Blood clotting

¨ Formation of pockets of fluid or fibrous tissue around the

implanted devices

¨ Damage to or paralysis of the surrounding nerves or

muscles

¨ Hoarseness

¨ Changes or abnormalities in heart rate or function

! Because implantation of the Lead may be associated with

nerve constriction (squeezing of the nerve), notify your

doctor immediately if you notice a constant hoarseness

within a few days after surgery. (There could be other

explanations for this symptom.)

Scars from the surgical procedure can be minimized. Talk to

your surgeon if you have particular concerns.

9.1.2. Pulse Generator Malfunction

The Pulse Generator can malfunction, though this is rare. The

stimulation associated with a malfunction can cause intense

neck pain, hoarseness, choking, or difficulty breathing.

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! Stimulation associated with a malfunction could damage

the vagus nerve, leading to permanent hoarseness or

other complications. In addition, it could cause the Pulse

Generator to reach end-of-service sooner than expected.

If you notice any of the symptoms described, or if

stimulation becomes painful, irregular, or continuous,

place the magnet over the Pulse Generator and hold it

there to stop stimulation (see the "Stopping Stimulation"

section of this manual). Then call your doctor

immediately.

9.1.3. Battery Depletion

The Pulse Generator battery will gradually lose its power

when it nears its end-of-service. At that point, it will begin to

stimulate differently—you may notice this as irregular

stimulation. Finally, the stimulation will stop altogether. (See

the "Checking Stimulation" section for how to verify whether

the device is stimulating.)

! After programmed stimulation stops (when the Pulse

Generator reaches end-of-service), seizure frequency,

intensity, or duration (or any combination) may

increase. Your seizures could increase to levels greater

than before stimulation started. If you suspect that the

Pulse Generator might not be stimulating properly,

call your doctor.

When the battery reaches its end-of-service, the Pulse

Generator can be replaced in a procedure that generally takes

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less than an hour. Replacement or removal of the Lead is a

different procedure and is not required for routine battery

replacement.

9.1.4. Manipulation of the Pulse Generator and Lead

Although the Pulse Generator is secured into place during

surgery, it is possible for the device to move (migrate)

slightly. It may be possible to feel the Lead under the skin

after surgery. This feeling is normal and should become less

apparent over a period of several weeks. Manipulation of the

Lead should be prevented at all times.

! Never move or twist the Pulse Generator or manipulate

the Lead. Doing so could damage the Lead or your vagus

nerve and could require that the Pulse Generator and

Lead be replaced.

9.2. Side Effects

Certain side effects are associated with the VNS Therapy

System and stimulation. With time, however, they generally

become less noticeable for most patients. Other discomforts,

such as difficulty breathing, can occur if Pulse Generator

settings are set too high initially or are increased too rapidly,

or if stimulation is started too soon after device implantation.

If this happens, your doctor can reprogram the stimulation

settings.

Because the VNS Therapy System is not a drug, it does not

cause drug-related toxic central nervous system side effects,

such as memory loss, confusion, drowsiness (sedation), and

difficulty concentrating. The most common side effect is

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hoarseness. The three other most commonly reported side

effects are sore throat, shortness of breath, and coughing.

These problems typically occur only during stimulation: the

ON time of the cycle, which is usually about 30 seconds every

five minutes. Most people who experience the hoarseness, as

well as the other three side effects, tolerate it well and notice it

less as time goes on.

! Notify your doctor any time the hoarseness becomes

persistent, uncomfortable, or continuous.

! Magnet settings should be tested while you are in the

doctor’s office to make sure you are able to tolerate the

settings. Stimulation—or the stoppage of stimulation—

can result in a worsening of seizures.

The following is a partial alphabetical list of the side effects

possibly associated with the VNS Therapy System that have

been reported in clinical trials. You may experience one or

more of them. If any one of the items below becomes too

uncomfortable, talk to your doctor:

¨ Lack of coordination in the voluntary muscles (ataxia)

¨ Difficulty breathing, shortness of breath (dyspnea)

¨ Hoarseness (voice alteration)

¨ Impaired sense of touch (hypesthesia)

¨ Inability to sleep (insomnia)

¨ Increased coughing

¨ Indigestion (dyspepsia)

¨ Infection

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¨ Inflammation of the pharynx, throat (pharyngitis)

¨ Muscle movements or twitching generally associated

with stimulation

¨ Nausea

¨ Pain

¨ Prickling of the skin (paresthesia)

¨ Throat, larynx spasms (laryngismus)

¨ Vomiting

These side effects could, potentially, occur:

¨ Aspiration (fluid in the lungs)

¨ Blood clotting

¨ Choking sensation

¨ Damage to nerves or blood vessels in the surgical area,

including the carotid artery and jugular vein

¨ Device (Generator and/or Lead) migration or extrusion

¨ Difficulty swallowing (dysphagia)

¨ Dizziness

¨ Duodenal ulcer, gastric ulcer

¨ Ear pain

¨ Facial flushing

¨ Facial paralysis, paresis

¨ Foreign body reaction to implants, including possible

tumor formation

¨ Formation of fibrous tissue, pockets of fluid

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¨ Heart rate and rhythm changes

¨ Hiccuping

¨ Incision site pain

¨ Irritability

¨ Left hemidiaphragm paralysis

¨ Left vocal cord injury or paralysis (affects voice)

¨ Low-grade fever

¨ Muscle pain

¨ Neck pain

¨ Nerve injury

¨ Painful or irregular stimulation

¨ Ringing in the ears (tinnitus)

¨ Skin, tissue reaction

¨ Sore, painful throat (laryngeal irritation)

¨ Stomach discomfortTooth pain

¨ Unusual scarring at the incision site

¨ Urinary retention

¨ Vagus nerve paralysis

¨ Weight change

¨ Worsening of asthma and bronchitis

¨ Worsening of cardiac abnormalities, including heart rate

and rhythm

9.3. Environmental Hazards

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Environmental hazards can occur when the Pulse Generator is

in close contact with certain types of equipment. Moving

away from or avoiding the equipment usually resolves the

problem.

Pacemaker Warning Signs: Seek medical advice before

entering areas where entry by a Pacemaker Patient is

cautioned.

9.4.2. Mammography

Because of where the Pulse Generator is implanted in your

chest, you may need to be specially positioned during

mammography procedures for clear imaging. Otherwise, the

device may be seen as a shadow on the mammogram and

could make a lesion or lump in the area of the device difficult

or even impossible to detect. Make sure that your doctor and

the mammography technician are aware of the implanted

device.

9.4.4. Magnetic Resonance Imaging

If you plan to have magnetic resonance imaging (MRI), make

sure your doctor has the following information:

! Magnetic resonance imaging (MRI) should not be

performed with a magnetic resonance body coil in the

transmit mode. The heat induced in the Lead by an MRI

body scan can cause injury.

If an MRI should be done, use only a transmit and receive

type of head coil. Magnetic and radiofrequency (RF) fields

produced by MRI may change the Pulse Generator settings

(change to reset parameters) or activate the device.

Stimulation has been shown to cause the adverse events

reported in the "Adverse Events" section of this manual.

MRI compatibility was demonstrated using a 1.5T General

Electric Signa Imager and Model 100 Pulse Generator only.

Testing on this imager as performed on a phantom indicated

that the following Pulse Generator and MRI settings can be

used safely without adverse events:

¨ Pulse Generator output programmed to 0 mA for the MRI

procedure, and afterward, retested by performing the

Lead Test diagnostics and reprogrammed to the original

settings

¨ Head coil type: transmit and receive only

¨ Static magnetic field strength: £ 2.0 tesla

¨ Specific-rate absorption (SAR): < 1.3 W/kg for a 70-kg

(154.5-lb) patient

¨ Time-varying intensity: < 10 tesla/sec

Use caution when other MRI systems are used, since adverse

events may occur because of different magnetic field

distributions.

! No scan in which the radiofrequency (RF) is transmitted

by the body coil should be done on a patient who has

the VNS Therapy System. Thus, protocols must not be

used which utilize local coils that are RF-receive only,

with RF-transmit performed by the body coil. Note that

some RF head coils are receive only, and that most other

local coils, such as knee and spinal coils, are also RFreceive

only. These coils must not be used in patients

with the VNS Therapy System.

9.4.5. Other Procedures

External cardiac defibrillation and other procedures for heart

problems, as well as extracorporeal shockwave lithotripsy,

diathermy, and electrocautery, may damage the Pulse

Generator. If any of these procedures have been performed

without the knowledge of your doctor, have the Pulse

Generator checked for correct operation.

While diagnostic ultrasound should not affect the VNS

Therapy System, therapeutic ultrasound therapy could

damage the Pulse Generator or inadvertently harm you by

concentrating the therapy

9.5.2. Implanted Devices

The Pulse Generator may affect the operation of other

implant-ed medical devices, such as cardiac pacemakers and

implant-able defibrillators. Possible effects include sensing

problems, which could lead to inappropriate Pulse Generator

responses.

Hi Gbean: I don't believe I got that manuel and if I did get if it was after the operation.lol HadI got it before the operation, I doubt I would have allowed to the operation to go thru.They did give me a video, which I didn't want to watch,My husband put it on and of course the tpae was broken?????

Thanks for the info , I should have gotten before the operation

Positive person