Neuromodulation: Offering Hope to People in Pain

For nearly two decades, he lived with phantom pain following an amputation. DRG Therapy gave Raul Silva relief.

Pain and Movement | Sep. 24, 2020

Raul Silva woke up in the middle of the night and shot out of bed. He was so excited that he was shouting.

"Something's missing! Something's missing!"

His wife gave him a sideways glance, wondering what had gotten into him.

"The pain is gone!"

Earlier that day, Silva began a weeklong trial with DRG Therapy, the latest in neuromodulation advancements for chronic pain management. For 18 years, he had lived with severe phantom limb pain after his left leg was amputated. The pain in Silva's leg had only gotten worse with time; it was particularly excruciating whenever he needed to use the restroom.

But on this particular night, he knew he finally found something that would make a difference.

Living With Chronic Pain

In 2000, Silva was in a motorcycle accident near the California-Mexico border. He was treated for a broken femur in Mexico, but when he returned to California, the limb had developed gangrene. His leg needed to be amputated above the knee.

"When I woke up after the amputation, my leg felt so cold, like my foot was touching the metal bed," he said. "I needed to sit up, to go outside and feel the sun."

That was the start of his phantom limb pain. For nearly two decades, Silva tried managing his pain with over-the-counter medications. A few years ago, his doctor prescribed him prescription pain medications. Neither worked.

"The medicines make me sleepy, and the only pain relief I get is in my sleep," he said.

But it was hardly sleep and wasn't much of a relief. Silva would toss and turn, his wife told him, and his body still reacted as though it was in pain, even if his mind was asleep.

"When I wake up, I feel sore," Silva said. "My head aches. I feel sleepy all day."

Through the pain, Silva still went to his job at a department store — where he walked and stood on his prosthetic leg for long periods of time — and raised his three daughters.

"Work was good in some ways because it kept me busy," he said. "Taking care of customers, I was too worn out to think about the pain. But the pain was still so bad. Some days it would get so bad, I could do nothing but lie on the floor. The pain would become so severe, I would need to go to the emergency room."

Invisible Trial, Palpable Relief

Eventually, Silva's doctor wrote a letter advocating for Silva to be placed on permanent disability. The pain of being on the prosthetic and the attendant risks to his health were too great. Working, standing for so long, was out of the question. Silva's doctor also recommended that he try Proclaim DRG (Dorsal Root Ganglion) therapy, which uses mild electrical signals to treat chronic pain. Proclaim DRG therapy is an aid in the management of moderate to severe chronic intractable pain of the lower limbs in adult patients with complex regional pain syndrome (CRPS) types I and II. Silva had no idea what that meant.

With Proclaim DRG therapy, a physician places thin wires near the dorsal root ganglion — a bundle of nerves in the spinal column that regulates pain signals — and connects them to an implanted generator. It works by sending mild electrical pulses to the nerves responsible for the painful sensations. This could reduce or completely block the pain from the affected nerve to the brain. Those using Proclaim DRG therapy receive a controller to adjust the strength of the pulses as needed. Silva's doctor offered him a weeklong trial.

"I said I wanted to try it because trying something was better than doing nothing," Silva said.

The DRG Invisible Trial System begins with a short outpatient procedure wherein thin wires are placed near the DRG and hooked up to a small, external battery that's worn discreetly under street clothes. It's not exactly invisible, but it's pretty close.

For his procedure, Silva was put under light anesthesia while doctors made an incision for the leads.

They tested the stimulation to make sure leads were positioned in the spot associated with Silva's pain. Then they put him back under. That's how the doctors knew the leads were positioned in the spot associated with Silva's pain. They put him back under anesthesia and finished the procedure. Upon waking, his care team turned on the device and gave Silva an Appleǂ iPod touchǂ. During the trial, Silva used the iPod to change the stimulation settings on his generator to see how the therapy targeted his pain symptoms.

"When I turn (the iPod) on, I see a body, and the parts connected to your body are highlighted in blue," he said. "I choose the area that hurts and put more strength on it. It's so easy to handle. Not too many steps."

Even as he left the hospital that day, Silva felt like a new person.

"Besides the phantom limb pain, I have sciatic nerve pain," he said. "It was gone. Everything was wonderful. For the first time, I felt normal."

Choosing the Next Steps

Silva kept the Invisible Trial for the full seven days. Each day, he discovered that he could do a little more. He could take his teenage daughters to and from school and extracurricular activities. He could help around the house, visit family and friends.

"I was able to walk my dog again," Silva chuckled. "My wife would ask why I was smiling and laughing when we'd go out walking. For the first time, I could wear the prosthetic and feel good. With the phantom pain, I would feel like my foot is touching my shoes, or my leg is there with the prosthetic."

Whenever his pain flared up, he simply opened his iPod, targeted the body part and delivered more stimulation. When the pain subsided, he set the strength back to normal. He felt great.

"I just want to be a normal amputee," he said. "I can't have my leg back, and I don't want it. But the pain, that's the thing. I've been suffering so badly for 18 years. I want a better quality of life, for my family to not have to worry about me. I want to walk my dog in the park." Neuromodulation advancements won't just benefit Silva's chronic pain management. They're a relief for his family, too.

"Proclaim DRG therapy may mean even more to my wife than to me," he continued, his voice breaking as he illustrates how much his wife has supported — and suffered with — him over the years. "From the beginning, she was with me through everything. Being free of pain would mean I can have quality time with my family, travel more, finish college, enjoy being with relatives. There's finally something that works."

Indications and Important Safety Information

DORSAL ROOT GANGLION (DRG) THERAPY

PRESCRIPTION AND SAFETY INFORMATION

Read this section to gather important prescription and safety information.

INTENDED USE

This neurostimulation system is designed to deliver low-intensity electrical impulses to nerve structures. The system is intended to be used with leads and associated extensions that are compatible with the system.

INDICATIONS FOR USE

US:

This neurostimulation system is indicated for spinal column stimulation via epidural and intraspinal lead access to the dorsal root ganglion as an aid in the management of moderate to severe chronic intractable* pain of the lower limbs in adult patients with complex regional pain syndrome (CRPS) types I and II.**

*Study subjects from the ACCURATE clinical study had failed to achieve adequate pain relief from at least two prior pharmacologic treatments from at least two different drug classes and continued their pharmacologic therapy during the clinical study.

**Please note that in 1994, a consensus group of pain medicine experts gathered by the International Association for the Study of Pain (IASP) reviewed diagnostic criteria and agreed to rename reflex sympathetic dystrophy (RSD) and causalgia as complex regional pain syndrome (CRPS) types I and II, respectively. CRPS II (causalgia) is defined as a painful condition arising from damage to a nerve. Nerve damage may result from traumatic or surgical nerve injury. Changes secondary to neuropathic pain seen in CRPS I (RSD) may be present, but are not a diagnostic requirement for CRPS II (causalgia).  

International:

This neurostimulation system is indicated for the management of chronic, intractable pain.

CONTRAINDICATIONS

This system is contraindicated for patients who are

Unable to operate the system

Poor surgical risks

Pregnant

Under the age of 18

MRI SAFETY INFORMATION

Some models of this system are Magnetic Resonance (MR) Conditional, and patients with these devices may be scanned safely with magnetic resonance imaging (MRI) when the conditions for safe scanning are met. For more information about MR Conditional neurostimulation components and systems, including equipment settings, scanning procedures, and a complete listing of conditionally approved components, refer to the MRI procedures clinician's manual for neurostimulation systems (available online at manuals.sjm.com). For more information about MR Conditional products, visit the Abbott product information page at neuromodulation.abbott.

WARNINGS

The following warnings apply to this neurostimulation system.

Pregnancy and nursing. Safety and effectiveness of neurostimulation for use during pregnancy and nursing have not been established.

Pediatric use. The safety and effectiveness of neurostimulation for pediatric use have not been established.

External defibrillators. Safety for use of external defibrillator discharges on a patient receiving neurostimulation has not been established. External defibrillation can cause induced currents in the lead-extension portion of the neurostimulation system. After defibrillation, confirm the neurostimulation system is still working

Magnetic resonance imaging (MRI). Some patients may be implanted with the components that make up a Magnetic Resonance (MR) Conditional system, which allows them to receive an MRI scan if all the requirements for the implanted components and for scanning are met. A physician can help determine if a patient is eligible to receive an MRI scan by following the requirements provided by Abbott Medical. Physicians should also discuss any risks of MRI with patients.

Patients without an MR Conditional neurostimulation system should not be subjected to MRI because the electromagnetic field generated by an MRI may damage the device electronics, cause heating at the lead tip that could result in tissue damage, and induce voltage through the lead that could jolt or shock the patient.

Diathermy therapy. Do not use short-wave diathermy, microwave diathermy, or therapeutic ultrasound diathermy (all now referred to as diathermy) on patients implanted with a neurostimulation system. Energy from diathermy can be transferred through the implanted system and cause tissue damage at the location of the implanted electrodes, resulting in severe injury or death.

Diathermy is further prohibited because it may also damage the neurostimulation system components. This damage could result in loss of therapy, requiring additional surgery for system implantation and replacement. Injury or damage can occur during diathermy treatment whether the neurostimulation system is turned on or off. Advise patients to inform their healthcare professional that they should not be exposed to diathermy treatment.

Electrosurgery. To avoid harming the patient or damaging the neurostimulation system, do not use monopolar electrosurgery devices on patients with implanted neurostimulation systems. Before using an electrosurgery device, place the device in Surgery Mode using the patient controller app or clinician programmer app. Confirm the neurostimulation system is functioning correctly after the procedure.

During implant procedures, if electrosurgery devices must be used, take the following actions:

Use bipolar electrosurgery only.

Complete any electrosurgery procedures before connecting the leads or extensions to the neurostimulator.

Keep the current paths from the electrosurgery device as far from the neurostimulation system as possible.

Set the electrosurgery device to the lowest possible energy setting.

Confirm that the neurostimulation system is functioning correctly during the implant procedure and before closing the neurostimulator pocket

Implanted cardiac systems. Physicians need to be aware of the risk and possible interaction between a neurostimulation system and an implanted cardiac system, such as a pacemaker or defibrillator. Electrical pulses from a neurostimulation system may interact with the sensing operation of an implanted cardiac system, causing the cardiac system to respond inappropriately. To minimize or prevent the implanted cardiac system from sensing the output of the neurostimulation system, (1) maximize the distance between the implanted systems; (2) verify that the neurostimulation system is not interfering with the functions of the implanted cardiac system; and (3) avoid programming either device in a unipolar mode (using the device’s can as an anode) or using neurostimulation system settings that interfere with the function of the implantable cardiac system

Emergency procedures. Instruct patients to designate a representative (family member or close friend) to notify any emergency medical personnel of their implanted neurostimulation system if emergency care is required. Patients will receive an identification card to carry with them that will inform emergency medical personnel of their implanted system. Advise patients to use caution when undergoing any procedure that could include radiofrequency (RF) or microwave ablation, defibrillation, or cardioversion.

Ultrasonic scanning equipment. The use of ultrasonic scanning equipment may cause mechanical damage to an implanted neurostimulation system if used directly over the implanted system.

Therapeutic radiation. Therapeutic radiation may damage the electronic circuitry of an implanted neurostimulation system, although no testing has been done and no definite information on radiation effects is available. Sources of therapeutic radiation include therapeutic X rays, cobalt machines, and linear accelerators. If radiation therapy is required, the area over the implanted IPG should be shielded with lead. Damage to the system may not be immediately detectable.

Restricted areas. Warn patients to seek medical guidance before entering environments that could adversely affect the operation of the implanted device, including areas protected by a warning notice preventing entry by patients fitted with a pacemaker.

Component manipulation by patients. The patient must be instructed to not rub or exert pressure on implanted components through the skin as this may cause lead dislodgement leading to stimulation at the implant site, IPG inversion leading to the inability to communicate with the device, or skin erosion that can lead to another surgical procedure or possible infection.

Lead movement. Patients should be instructed to avoid bending, twisting, stretching, and lifting objects over 2 kg (5 lb) for at least six weeks after implantation. These activities may cause lead movement, resulting in under stimulation or overstimulation for the patient. Excessive lead migration may require reoperation to replace the leads.

Scuba diving and hyperbaric chambers. Instruct patients to avoid scuba diving and entering hyperbaric chambers above 1.5 atmospheres absolute (ATA) because these activities might damage the neurostimulation system.

Operation of machines, equipment, and vehicles. In the clinical experience with this device, patients have experienced few effects when moving from lying down to sitting up. Therefore, it is unlikely patients will need to adjust stimulation when changing positions or moving. However, advise patients who feel uncomfortable paresthesia during postural changes that they should not operate potentially dangerous equipment such as power tools, automobiles, or other motor vehicles. These patients should not climb ladders or participate in activities where postural changes or abrupt movements could alter the perception of stimulation intensity and cause patients to fall or lose control of equipment or vehicles or injure others.

Explosive and flammable gases. Do not use a clinician programmer or patient controller in an environment where explosive or flammable gas fumes or vapors are present. The operation of these devices could cause them to ignite, causing severe burns, injury, or death.

Keep the device dry. Programmer and controller devices are not waterproof. Keep them dry to avoid damage. Advise patients to not use their device when engaging in activities that might cause it to get wet, such as swimming or bathing.

Device components. The use of components not approved for use by Abbott Medical with this system may result in damage to the system and increased risk to the patient.

Device modification. The equipment is not serviceable by the customer. To prevent injury or damage to the system, do not modify the equipment. If needed, return the equipment to Abbott Medical for service.

Application modification. To prevent unintended stimulation, do not modify the operating system in any way. Do not use the application if the operating system is compromised (i.e., jailbroken).

Case damage. Do not handle the IPG if the case is pierced or ruptured because severe burns could result from exposure to battery chemicals.

IPG disposal. Return all explanted IPGs to Abbott Medical for safe disposal. IPGs contain batteries as well as other potentially hazardous materials. Do not crush, puncture, or burn the IPG because explosion or fire may result.

Product materials. Neurostimulation systems have materials that come in contact or may come in contact with tissue. A physician should determine whether or not a patient may have an allergic reaction to these materials before the system is implanted.

PRECAUTIONS

The following precautions apply to this neurostimulation system.

General Precautions

Clinician training. Implanting physicians should be experienced in the diagnosis and treatment of chronic pain syndromes and have undergone surgical and device implantation training.

Patient selection. It is extremely important to select patients appropriately for neurostimulation. Thorough psychiatric screening should be performed. Patients should not be dependent on drugs and should be able to operate the neurostimulation system.

Infection. Follow proper infection control procedures. Infections related to system implantation might require that the device be explanted.

Implantation of multiple leads. If multiple leads or extensions are implanted, the leads and extensions should be routed in close proximity. Nonadjacent leads and extensions have the possibility of creating a conduit for stray electromagnetic energy that could cause the patient unwanted stimulation.

High stimulation outputs. Stimulation at high outputs may cause unpleasant sensations or motor disturbances, or render the patient incapable of controlling the stimulator. If unpleasant sensations occur, the device should be turned off immediately.

Postural changes. In the clinical experience with this device, patients have experienced few effects when moving from lying down to sitting up. Therefore, it is unlikely patients will need to adjust stimulation when changing positions or moving. However, some patients may experience a decrease or increase in the perceived level of stimulation. Perception of higher levels of stimulation has been described by some patients as uncomfortable, painful, or jolting. Advise patients who experience these types of stimulation changes to turn down the amplitude or turn off the IPG before making extreme posture changes or abrupt movements such as stretching, lifting their arms over their heads, or exercising. If unpleasant sensations occur, the IPG should be turned off immediately.

Sterilization and Storage

Single-use, sterile device. The implanted components of this neurostimulation system are intended for a single use only. Sterile components in this kit have been sterilized using ethylene oxide (EtO) gas before shipment and are supplied in sterile packaging to permit direct introduction into the sterile field. Do not resterilize or reimplant an explanted system for any reason.

Storage environment. Store components and their packaging where they will not come in contact with liquids of any kind.

Handling and Implementation

Expiration date. An expiration date (or “use-before” date) is printed on the packaging. Do not use the system if the use-before date has expired.

Package or component damage. Before opening any sterile package, verify the kit model number, that the kit is within its expiration (use-before) date, and that the packaging has not been damaged or compromised in any way. If the packaging has been compromised, the device is beyond its expiration date, or the sterile package or device show signs of damage, do not use the device as it may be compromised and could cause harm to the patient. Return any suspect components to Abbott Medical for evaluation.

Handle the device with care. The clinician programmer and patient controller are sensitive electronic devices that can be damaged by rough handling, such as dropping them on the ground.

Lead inspection. Carefully inspect the lead (in the sterile field) for damage after removing it from the sterile package. Damage to the lead body can cause improper function and stimulation or stimulation to areas other than the intended target.

Care and handling of components. Use extreme care when handling system components prior to implantation. Excessive heat, excessive traction, excessive bending, excessive twisting, or the use of sharp instruments may damage and cause failure of the components.

Component handling. Do not bend, kink, or stretch the lead body, sheaths, or other components as this may result in damage to the component and poor function.

Using surgical instruments. Do not use surgical instruments to handle the lead. The force of the instruments may damage the lead or stylet.

Component manipulation. Do not over-manipulate the sheath and lead system as this may result in trauma within the epidural space.

Stylet handling. Do not bend, kink, or use surgical instruments on the stylet, as this may damage it. Use care when reinserting a stylet. Too much pressure on the stylet could damage the lead, resulting in intermittent or loss of stimulation. Remove the stylet from the lead only when satisfied with lead placement. If the stylet is removed from the lead, it may be difficult to reinsert it.

Sheath insertion precaution. Do not insert the sheath into the epidural space without the lead or guidewire inserted, as this may cause injury to the dura.

Stabilizing the lead during insertion. When inserting the lead-sheath assembly through the needle into the epidural space, tighten the lead stabilizer to prevent lead migration out of the sheath. Failure to do so may cause harm to the patient such as damage to the dura.

Bending the sheath. Do not bend the sheath without the lead inside the sheath, as this will permanently kink it and make it difficult to deploy the lead.

Lead handling. If the operating field is bloody, wipe gloves, lead, stylet, and sheath before handling the lead. Failure to do so may result in difficulty delivering the lead.

Exposure to body fluids or saline. Prior to connection, exposure of the metal contacts, such as those on the connection end of a lead or extension, to body fluids or saline can lead to corrosion. If such exposure occurs, clean the affected parts with sterile, deionized water or sterile water for irrigation, and dry them completely prior to lead connection and implantation.

System testing. To ensure correct operation, always test the system during the implant procedure, before closing the neurostimulator pocket, and before the patient leaves the surgery suite.

Component disposal. Return all explanted components to Abbott Medical for safe disposal.  

Hospital and Medical Environments

High-output ultrasonics and lithotripsy. The use of high-output devices, such as an electrohydraulic lithotriptor, may cause damage to the electronic circuitry of an implanted IPG. If lithotripsy must be used, do not focus the energy near the IPG.

Home and Occupational Environments

Electromagnetic interference (EMI). Some equipment in home, work, medical, and public environments can generate EMI that is strong enough to interfere with the operation of a neurostimulation system or damage system components. Patients should avoid getting too close to these types of EMI sources, which include the following examples: commercial electrical equipment (such as arc welders and induction furnaces), communication equipment (such as microwave transmitters and high-power amateur transmitters), high-voltage power lines, radiofrequency identification (RFID) devices, some medical procedures (such as therapeutic radiation, static magnetic field [SMF] therapy, and electromagnetic lithotripsy), and some medical devices (such as bone growth stimulators, transcutaneous electrical nerve stimulation [TENS] devices, dental drills, and ultrasonic probes).  

Wireless use restrictions. In some environments, the use of wireless functions (e.g., Bluetooth® wireless technology) may be restricted. Such restrictions may apply aboard airplanes, in hospitals, near explosives, or in hazardous locations. If you are unsure of the policy that applies to the use of this device, please ask for authorization to use it before turning it on. (Bluetooth® is a registered trademark of Bluetooth SIG, Inc.)

Security, antitheft, and radiofrequency identification (RFID) devices. Some antitheft devices, such as those used at entrances or exits of department stores, libraries, and other public places, and airport security screening devices may affect stimulation. Additionally, RFID devices, which are often used to read identification badges, as well as some tag deactivation devices, such as those used at payment counters at stores and loan desks at libraries, may also affect stimulation. Patients who are implanted with nonadjacent multiple leads and patients who are sensitive to low stimulation thresholds may experience a momentary increase in their perceived stimulation, which some patients have described as uncomfortable or jolting. Patients should cautiously approach such devices and should request help to bypass them. If they must go through a gate or doorway containing this type of device, patients should turn off their IPG and proceed with caution, being sure to move through the device quickly.

Mobile phones. While interference with mobile phones is not anticipated, technology continues to change and interaction between a neurostimulation system and a mobile phone is possible. Advise patients to contact their physician if they are concerned about their mobile phone interacting with their neurostimulation system.

ADVERSE EFFECTS

In addition to those risks commonly associated with surgery, the following risks are associated with using this neurostimulation system:

Unpleasant sensations or motor disturbances, including involuntary movement, caused by stimulation at high outputs (if either occurs, turn off your IPG immediately.)

Undesirable changes in stimulation, which may be related to cellular changes in tissue around the electrodes, changes in electrode position, loose electrical connections, or lead failure or breakage

Stimulation in unwanted places (such as stimulation of the chest wall)

Lead migration, causing changes in stimulation or reduced pain relief

Epidural hemorrhage, hematoma, infection, spinal cord compression, or paralysis from placement of a lead in the epidural space

Cerebrospinal fluid (CSF) leakage

Tissue damage or nerve damage

Paralysis, weakness, clumsiness, numbness, sensory loss, or pain below the level of the implant

Pain or bleeding where the needle was inserted

Persistent pain at the electrode or IPG site

Escalating pain

Seroma (mass or swelling) at the implant site  

Headache

Allergic or rejection response to device or implant materials

Implant migration or skin erosion around the implant

Battery failure, leakage, or both

Hardware malfunction that requires replacing the neurostimulator

Pain from a noninjurious stimulus to the skin or an exaggerated sense of pain

Additional risks to the patients, as a result of the placement and stimulation of the lead in the area of the dorsal root ganglion (DRG), include pain from setting the stimulation parameters too high. This may occur once the lead is in place and is connected to the neurostimulator and activated. The neurostimulator is controlled by a trained operator and the starting point for the stimulation will be set to the lowest available settings. Additionally, all patients will be awake and conversant during the procedure to minimize the impact.