BACKGROUND: Spinal cord trauma is damage to the spinal cord. It may result from direct injury to the cord itself or indirectly from damage to surrounding bones, tissues, or blood vessels. A spinal cord injury often causes permanent changes in strength, sensation and other body functions below the site of the injury. It results in a change, either temporary or permanent, in its normal motor, sensory, or autonomic function. Patients with spinal cord injury usually have permanent and often devastating neurologic deficits and disability. (SOURCE: www.ncbi.nlm.nih.gov/pubmedhealth, www.emedicine.medscape.com, www.mayoclinic.com)
THINGS YOU DIDN'T KNOW: The International Standards for Neurological and Functional Classification of Spinal Cord Injury (ISNCSCI) is a widely accepted system describing the level and extent of injury based on a systematic motor and sensory examination of neurologic function. The following terminology has developed around the classification of spinal cord injuries:
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- Tetraplegia (replaces the term quadriplegia): Injury to the spinal cord in the cervical region with associated loss of muscle strength in all 4 extremities.
- Paraplegia: Injury in the spinal cord in the thoracic, lumbar, or sacral segments, including the cauda equina and conus medullaris. (SOURCE: www.emedicine.medscape.com)
SYMPTOMS: The ability to control one's limbs after a spinal cord injury depends on two factors: the place of the injury along the spinal cord and the severity of injury to the spinal cord. The lowest normal part of the spinal cord is referred to as the neurological level of the injury. The severity of the injury is often called "the completeness" and is classified as either complete or incomplete. Spinal cord injuries of any kind may result in one or more of the following signs and symptoms:
- Loss of movement
- Loss of sensation, including the ability to feel heat, cold and touch
- Loss of bowel or bladder control
- Exaggerated reflex activities or spasms
- Changes in sexual function, sexual sensitivity and fertility
- Pain or an intense stinging sensation caused by damage to the nerve fibers in your spinal cord
- Difficulty breathing, coughing or clearing secretions from your lungs SOURCE: (www.mayoclinic.com)
LATEST BREAKTHROUGHS: ReWalk is a motorized exoskeleton suit that enables patients with lower limb disabilities, including complete paralysis, to independently engage in ambulatory activities, including standing, walking and in some cases climbing stairs. ReWalk consists of a lightweight wearable brace support suit, motorized joints, rechargeable batteries, an array of sensors and a computer-based control system. Worn around the legs, chest and back, it fits closely to the body on top of everyday clothing. Patient stability during ambulation is provided by concurrent use of crutches. Patients with spinal cord and brain injuries, stroke, multiple sclerosis, cerebral palsy and other diseases that result in walking impairments are good possible candidates. (SOURCE: www.mossrehab.com)
Dr. Alberto Esquenazi, Director of the Gait and Motion Analysis Laboratory Moss Rehab and Chief Medical Officer for the Institute talks about a new device for spinal injury patients.
Tell us what ReWalk is essentially.
Dr. Esquenazi: ReWalk is basically an exoskeleton. It's a device that you wear on the outside of your body. It's not connected to you in any way. It has motors that basically move your hips and knees and allows an individual who's paralyzed usually from the waist down to ambulate, to walk again. Those individuals who have had a spinal cord injury that have severed their spine and rendered them paralyzed who otherwise would not be able to walk by using ReWalk are allowed to walk again.
How does that work?
Dr. Esquenazi: ReWalk has motors and each one of those motors works independently. There is a computer program that is run in a small computer that the patient carries in their backpack. There are batteries in that backpack as well. The patient uses very gentle body motions, I call it body language, in which the patient generates a tilt of their body forward, and by doing that the system senses that you want to take a step and the system takes a step.
Is it a smart computer?
Dr. Esquenazi: The computer is not smart but there are sensors that allow it to determine what function you're commanding. Now you'll see that patients wear a small watchlike device from which they can also use hand controls to do a variety of activities. They can basically command the system to go from sit to stand. The motors will get the person from the sitting position to the standing position. Then they can switch the mode and say now I want to walk and now the system will pick up their "body language" to generate the appropriate steps. They can use the wrist commander also to command when they want to go from standing to sitting and they can use the wrist controller in some cases to climb steps and descend steps. So the system really provides a freedom that is unprecedented when you compare that to the mobility that a wheelchair or braces allowed.
How much of a learning curve is there with something like this for patients? This is not something you can put on and go right away?
Dr. Esquenazi: It takes a little bit of learning because you have to learn the "body language" and you need to also learn the timing of it. When you generate a very gentle tilt forward of your body the system will generate a step and you need to coordinate that so that the next step is one that is fluid and fluent and that takes a little practice. It's not hugely difficult. We normally see that patients who have never used the system by the second session have a good sense of what it is that they need to do. They become proficient the more they use it. Some patients have a limited exposure to the system only about sixteen to eighteen sessions of training on the basis of the research trials that we've implemented. But some patients actually have had the opportunity to practice with it longer and those patients, the more they practice the more proficient they become at using the system.
Who is an ideal candidate, who would benefit from this and are there some patients for whom this wouldn't help?
Dr. Esquenazi: At this point the system is designed for individuals with spinal cord injury. The research trial that we completed was focused on patients who had what we in medicine call complete injuries. Meaning they have no volitional power they couldn't move any muscles below the waist. The future really will open the door to patients who have less paralysis than that. That has less involvement and may have some residual muscle function and will be able to use this to supplement their own reduced or limited ability to move. By using this external powered system and using these motors and batteries, you could go much faster and much longer compared to what you could do on your own muscle power if you were weakened by a spinal cord injury.
This seems almost futuristic, is this just a first step?
Dr. Esquenazi: It's not the first step. Others have tried devices to allow individuals who are paralyzed to walk again. I think that this is the beginning of the future in the sense that we've integrated a variety of new sensors, new computer technology, new software language and certainly batteries that are lighter and more powerful that can permit someone who is paralyzed to truly be able to walk. That they can wear this over their regular street clothing that allows them to remove it if they want to do so, that allows them to put it on if they want to do so. Most importantly, that in the future will allow them to really replace the use of a wheelchair. For home use for example, they will be able to just be completely mobile independent using a device like ReWalk. The other huge advantage is one of environmental interaction. If you think about engaging yourself with the environment from a wheelchair is very different than when you are standing on two feet because things are designed for standing. If you want to reach in to a bookshelf or in to a cabinet it's usually higher up than if you were sitting. Being able to if you can imagine be at home and suddenly be standing and be able to reach in to a cabinet and take a dish or a glass or a book or a kitchen utensil how it would be a huge advantage. The idea of being eye to eye with another person and being able to interact in the same way at the same level. Individuals who sit in wheelchairs will tell you that looking up or having been looked at down is perceived to be a disadvantage. Suddenly you're putting people at the same level to interact with the environment and with each other.
When will they be bale to use it at home?
Dr. Esquenazi: ReWalk is currently approved by the Food and Drug Administration for what's called institutional version. That means that the device must be used under the supervision of an institution. The device is basically sold to an institution and the staff in that institution is trained to use the device and then they provide it as a therapeutic intervention. It's a therapy training program which is very common when you think about many other therapy interventions. That's a good way to do it. The device will continue to progress, right now there are a few centers across the country which have the ReWalk for institutional use. More will come on line in the next several months. Moss Rehab was the very first one to start with this treatment strategy. I expect that the next step will be to move to the version that will be the home or the patient use device in which they will be able to obtain a device and use it for all their activities every day.
Who would not benefit from his?
Dr. Esquenazi: We don't know that with scientific information, but it is my clinical impression that at this point individuals with either very recent or remote injuries will benefit. In fact, in our group of patients when we did our trial those research subjects had a injury that spanned in an average eight years, but we have patients who have had an injury nearly thirteen years ago and more recent injuries. All of those patients learned to use the device, learned to walk with the device, learned to be able to obtain independent mobility with ReWalk.
Why would people with recent injuries have potentially more of a response to this?
Dr. Esquenazi: I don't know that they will have necessarily more response but what you need to understand is that an individual who has a spinal cord injury and the resulting neurological injury will create the paralysis and along with the paralysis there is a tendency to lose muscle mass. Your muscles atrophy because of disuse. More important than that is, the bones tend to lose their strength over time, bones lose their calcium, their mineral strength as time goes on. In patients who have neurological injuries it is well documented in the scientific world that they tend to lose more bone and faster than normals. If you have someone who has been paralyzed for many years reversing that bone loss is going to be a much bigger effort but if you are recently injured, We can prevent the loss of bone that would be a huge advantage, a huge gain in the healthcare of this individual.
How is it for patients who haven't walked for a while? It must be gratifying for you to stand here and watch them get up and move forward.
Dr. Esquenazi: Very gratifying to see them get to that point. It's very emotional for me to see them really go from a sitting position to somebody being on their own power stand up, because they're wearing the ReWalk suit which is doing that for them. They are really interacting with the world in a very different perspective. It's quite emotional to see that happen. Whenever we as clinicians do any intervention we're always proud of what we're doing because we're seeing a change. But is that change the all that it's meant to be and the patient is the best person to answer that question.
Is there anything you would like people to know?
Dr. Esquenazi: Probably people would wonder how heavy is the device; I always get that question asked. That question is really of no significant importance because even though the device is almost forty pounds in weight, patients are not carrying the device. They always have one foot on the ground and this system is built so that it is self sustaining, self supporting and so you don't need to worry about that.
Is it waterproof if you're out in the rain?
Dr. Esquenazi: I think its weather proof but I don't know if it's water proof. If a patient jumped in to a pool or try to take it in to the shower that wouldn't be recommended. As currently designed the system would get damaged if it was emerged in water, but if it got exposed to rain nothing would happen to it. The system would tolerate that. There are motors and gears and electrical connections and batteries so it's not a good recipe for jumping in to the pool.
How close is this to Avatar?
Dr. Esquenazi: The idea of Avatars is that these devices that are created really to take over the patient, this is really one of the very important different premises of ReWalk. ReWalk is the patient taking over the control of the equipment. This is why you have to have "body language", you need to be the one that generates the step. There are now in research trials two other systems that are following the steps of ReWalk. One of them uses movement of your arms to generate stepping pattern so as you move your arm forward it takes a step. As you can see now it's changing the paradigm. It's not walking, it's moving your arms that make you walk. The developer of the Re-Walk system really thought about a way in which the system was unobtrusive in the way you have to behave in order to interact with the system and looked at normal walking. If you think about when you walk you gently tilt your body forward and that's how you walk. This is exactly what ReWalk does. You gently tilt your body forward and it takes a step for you instead of having to generate a different type of command or think about walking. He wanted to really make it as intuitive as possible and I think he's made a good step with that.
FOR MORE INFORMATION, PLEASE CONTACT:
Judy Horwitz
Senior Communications Specialist
Albert Einstein Healthcare Network
(215) 456-6767
horwitzj@einstein.edu