SCI Forum Reports
Pain and SCI
May 14, 2002
"It isn't all bad," said Bob about his SCI pain. "If you have SCI, sometimes it's nice to feel something in the lower regions, even though it might be painful." Bob, who has a cervical injury, was one of the panelists at this evening's SCI Forum on pain after SCI.
"You can sometimes use that pain to advantage," he continued. "I can tell when I'm sitting on my butt too long because it begins to burn. That gets me moving. It has kept me from getting a decubitus over the years.
"New versus old injuries produce different kinds of pain. When you're first hurt, you have pains that are really weird. You can't figure out what's going on. You may have pain like someone is standing on your foot for days. Or feel like you've got to pee or poop for days on end. There are all these sensations, like an amputee who can feel fingers that aren't there.
"As you get further along in your injury, a lot of those weird pains go away. If you have spasticity, sometimes there'll be a dull pain coming on before you get a spasm-a warning that it's going to kick in.
"You may get a bladder or bowel sensation you might be able to use. I get a lot of pain in my back, neck and limbs. Sometime, with your mind, you have to take that pain and put it aside. It takes a certain amount of mental energy to get past the pain. I always have pain. That's why I'm always turning and twisting around." Bob avoids take pain medications because they diminish his mental alertness.
Steve, a panelist with a T2 injury, reported having pain in his right leg that "goes on constantly. Sometimes I take an Advil® or Tylenol 3® just to get to sleep. Squirming does help me a lot."
"I'm in constant pain," said Shannon, a man with tetraplegia. "From my level of injury all the way to my toes."
Shannon described his pain as burning and tingling. "I've tried several types of pills, with no success. All you can do is try to mentally block it out. The only time I don't feel pain is when I'm asleep. The rest of the time, you have to get up and go on."
"No one knows someone else's pain," said John D. Loeser, MD, professor in the Department of Neurological Surgery. "You know only your own pain. You can observe somebody else's pain behavior, and you can ask about intensity, quality, when, how does if affect your life."
SCI pain is not due to something wrong at the level of injury, Loeser explained. "Your pain is due to something that is happening in your brain because of changes that occurred in the nervous system. But those changes aren't resident in the region of injury. They're resident up here," he said, pointing to his head. "The brain is the organ of pain."
"As all three of these panelists said, pain can be modulated by a variety of events, both internal and external. It doesn't matter what your pain is due to. If you're worried that your pain means something bad is happening.it hurts a lot more."
There are different cognitive strategies people can use to influence pain, such as distraction or positive thinking. "This is not unique to SCI pain, because the pain is coming from your brain, and what you do with your brain modulates or influences pain of all sorts."
"I look upon SCI pain as a sort of journey we're taking, because the fact is we don't know a lot about it."
Loeser presented three case studies to demonstrate the wide range in pain experiences even when injuries are similar.
Patient 1. A 33 year-old-female with C7 paraplegia from a skiing accident in 1992. She had an immediate posterior fusion. She resumed work as an administrative assistant three months after injury, takes no medications, and describes a fulfilling life with no pain.
Patient 2. A 42-year-old male with T8 paraplegia from a motorcycle accident at age 26. He had a posterior fusion with Harrington rods. He developed severe spasticity and pain below the level of injury. Intrathecal baclofen controlled his spasticity but intrathecal opioids provided no pain relief. He uses oxycodone with fair relief of pain, is unemployed, but leads an active life.
Patient 3. A 53-year-old male with complete C7 tetraplegia from a car accident at age 46. He developed pain and spasticity below the level of the lesion. Intrathecal baclofen controlled his spasticity but he has no relief from pain with intrathecal morphine. He is depressed and on "high doses of antidepressants, anticonvulsants and oral opioids, with no obvious beneficial effects," Loeser said. "And as you pointed out (Bob), all those medications make you stoned and it's hard to do anything, and that's exactly the way he wanted to be. He didn't want to face the world around him."
"So here are three people with similar motor and sensory deficits who have totally different pain problems," Loeser continued. "One has no pain. One has pain but is functional. And one has pain and is totally devastated and nonfunctional. Yet their injuries look very similar. Knowing the injury tells you nothing about the likelihood of having pain. Some SCI patients have pain and some do not. It's not related to the level of injury and it's a big mystery as to why."
Pain in SCI patients can be difficult to manage. A multi-disciplinary effort is needed to establish diagnosis and determine a treatment approach.
SCI pain is reported inconsistently in the medical literature. The more recent articles report higher incidences of pain-from 25% to 85%- than earlier articles, Loeser said. This may be due to the fact that in the past, SCI patients weren't often asked about pain. "Indeed, in the most famous treatise on SCI in the first half of the 20th century (Monroe) there was not one word about pain," he noted. Many journal articles published after World War II discussed pain, but there was huge variation in the prevalence of pain, for two reasons. First, there are many different kinds of pain after SCI, and people often look at only one type of pain and miss the others. And second, until recently, physicians didn't ask if patients had pain. They only knew about it if the patient volunteered the information. Loeser surmises that doctors weren't interested in hearing about SCI pain because it is so difficult to manage; patients knew that and kept quiet.
Level of injury, completeness, age, gender and pre-existing psychosocial factors are not predictors of pain after SCI. "As all rehabilitation physicians know very well," Loeser said, "chronic pain is often a greater cause of disability than paralysis after SCI. Chronic pain is the major reason why patients can't meet their expected functional level after an SCI."
The diagnosis of an SCI pain problem is usually determined from the general history and physical examination of the patient, although other methods are also routinely employed, including neurological assessment; mechanical evaluation of spine and limbs; imaging studies such as MRIs and CTs; and electrodiagnostic studies.
There are two types of SCI pain. Nociceptive or "normal" pain is caused by the activation of the tissue damage detection system in the peripheral tissues, usually associated with trauma or inflammation. In nociceptive pain, neural pathways are working normally, signaling that there is something wrong going on where it hurts. Neuropathic pain is "abnormal" in that damage to the peripheral or central nervous system causes pain in the absence of peripheral nociceptor activation or any identifiable disturbance in the location of the pain.
Loeser described the seven different categories of SCI pain.
Mechanical instability . This is musculoskeletal pain due to fracture or ligamentous disruption. "Probably none of you have this," Loeser said. "We used to see a lot of this in earlier days before we went into the phase of doing prompt fusions, often using metal to increase the likelihood of a solid fusion. This type of pain starts at the time of injury and is made worse by moving and position."
It is described as aching or cramping in the region of the spinal injury. Not unique to SCI, "it's the same thing that would hurt if you broke a bone anywhere, with activation of the nociceptors in the region of tissue damage," Loeser continued. "The nervous system is working appropriately. It's a "normal" pain in that you can predict that this would hurt because of your knowledge of what happens in the region of a fracture. You can almost always cure this pain with an operation or immobilization. Now we see much less of this kind of pain because of more aggressive and earlier surgery to restore stability to the spine."
Nerve root entrapmen t. This occurs acutely, soon after injury, and is caused by compression of a nerve root. "Leaving the spinal cord at every level is a nerve root that goes to the body," Loeser explained. "Compress it and you can produce pain. The pain is due to the fact that the nerve root itself is innervated (supplied with nerves) and sensitive to pain, and the dorsal root ganglian cells that live in the nerve root are also mechanically sensitive. It is described as radiating pain around the body at a single level. Usually decompressing the nerve root relieves the pain. A good, non-SCI example of this kind of pain is a ruptured disk."
Transitional zone (girdle-zone or segmental deafferentation) pain . The transition zone starts from where normal sensation begins, above the injury, and goes down to where sensation stops, below the injury, often spanning more than one level. Pain is often felt in that zone, and it is associated with allodynia, meaning light touch is painful. "It can be treated with methods that make the transition zone anesthetic," Loeser said. "Surgery to cut the nerve roots in the transition zone can stop the pain, but this raises the level of injury. This pain sometimes responds to oral medications, especially anticonvulsants and antidepressants."
Central Dysesthesia Syndrome . The pain described by all three panelists would fall into this category, according to Loeser. "Pain is perceived in the anesthetic areas, below the level of injury. It responds poorly to any treatment and is the hardest pain to treat. Onset is usually soon after injury. The origin may be in the spinal cord or the brain. There is some evidence that it is in the brain."
Secondary overuse or pressure syndromes . These are treatable, "normal" pains occurring in normally innervated areas and are due to overuse or abnormal pressure. "Basically, when you use your shoulders as hips (for pushing a manual wheelchair), your shoulders don't like it, nor does your wrist," Loeser said. "We see lots of people (with SCI) with rotator cuff problems, carpal tunnel syndrome. The nervous system is working appropriately." This type of pain is relieved by rest, positioning and NSAIDs (non-steroidal anti-inflammatory medications).
Visceral pain . Pain that occurs in the abdomen but whose cause cannot be determined. When a patient reports abdominal pain, "you need to look for some visceral cause," Loeser explained, "but in most cases, you don't find a treatable problem, and we assume it's just another part of the spinal cord pain picture."
Muscle spasm pain . Only present in incomplete injuries, usually delayed in onset, this pain is treated by eliminating the spasm. "You don't treat it as a pain problem," Loeser said, "you treat it as a spasm problem."
Syringomyelia . In about 2% of the SCI population, a fluid-filled cavity (syrinx) forms in the spinal cord, causing new neurological deficits and pain. It is diagnosed by MRI or CT. Onset occurs usually years after injury. "Treatment is not as easy as diagnosis," Loeser noted. "The only way we know of to treat it is to drain the syrinx. If left alone, and the patient has symptoms, the symptoms will progress. Some people with small syrinxes never have symptoms."
Cognitive and affective factors also influence pain. "These factors are commonly ignored in our biomedically fixated healthcare system," Loeser remarked. As with other chronic pain problems, psychological and behavioral approaches to pain management can be helpful in SCI pain.
"Better treatments for pain after SCI will be based on new and better understanding of pain mechanisms," he added. "There may be a genetic factor in the nervous system that determines pain."
Loeser is conducting a study for people with SCI and central dysesthetic pain syndrome. "We're taking fetal nerve cells and placing them into the damaged spinal cord in hopes the cells will produce chemical substances that will restore the nerve cells back to normal," Loeser explained. "It is a highly experimental, Phase 1 study to determine safety and efficacy." For more information, call Susan Strom at 206-598-4596.