education 4

SESSION 4

Neurophysiology of Pain and Surgical Interventions

SESSION 4Neurophysiology of Pain & Surgical Interventions

Objectives:1. Introduce the basic concepts of the neurophysiology of pain.2. Introduce aspects related to deciding to have surgery.3. Introduce types of surgery.

Skills:By the end of this session, you should be able to…

1. Demonstrate comprehension of the basic concepts of the neurophysiology of pain.

2. Demonstrate comprehension of the aspects related to deciding to have surgery & types of surgery.

Learning Activities:1. Group Discussion2. Quiz

SESSION 4: Neurophysiology of Pain; Surgical Interventions 1

NEUROPHYSIOLOGY OF PAIN It is important for people with chronic pain to have an accurate and realistic understanding of some of the biological aspects of pain. The following information is intended to give you a greater appreciation for the biological complexities regarding the way our bodies experience pain. Pain messages travel through the body to the brain in a certain fashion.

Group ActivityPlace the following sentences in the correct order as fast as you can.

1. Ultimately, the pain messages are registered by various parts of the brain.

2. From the spinal cord they are transmitted up toward the brain.

3. Sensitive nerve endings pick up the painful sensations.

4. Painful sensations arise from injured or damaged body tissues.

5. Sensitive nerve endings carry pain messages along nerves to the spinal cord.

The correct order is: ___, ___, ___, ___, and ___

ROLE OF THE NERVOUS SYSTEMAs we have just learned, the most important body structure involved in the experience of pain is the brain. At least five parts of the brain are involved in the experience of pain. These may be referred to as the sensory, emotional, memory, evaluative, and action centers. The sensory centers give us information as to the location, quality, and intensity of pain sensations. The emotional centers serve to motivate us to act in ways to minimize the pain or seek relief. The memory centers enable us to compare our immediate experience of pain with previous experiences of pain. The memory centers also work together with the evaluative centers. Based upon our past experiences with pain, we automatically make evaluations about the cause or meaning of the pain, as well as decisions regarding what to do about the pain. Finally, the action centers become activated as we seek to do something about the pain. These action centers include both automatic reflex actions, as well


as actions based upon our conscious evaluation of the pain and decisions regarding what to do about it.

RELATIONSHIP BETWEEN PHYSICAL INJURY AND THE EXPERIENCE OF PAINNormally, what the mind/brain tells us is a very accurate representation of what is happening in the injured part of our bodies. If you accidentally stub your toe, your brain immediately tells you that your toe is hurt. In other words, our nervous system enables us to quickly respond to pain as a signal warning us of injury. This all assumes, of course, that your nervous system is fully intact and operational. If you have some kind of nerve damage, it may be possible to stub your toe and not feel any pain sensations in the brain. In other words, it is possible to have an injury and no pain. This is an example of a situation in which the experience of injury and pain do not coincide.

ROLE OF THE SPINAL GATEA number of years ago, pain researchers described a complex gate mechanism within the spinal cord that determines what amount of pain signals actually reach the brain. If the spinal gate is wide open, all available pain messages reach the brain, whereas if the gate is completely closed, no pain messages reach the brain. In reality, the gate is neither completely open nor completely shut. Rather, it works like a light dimmer switch that determines the intensity of pain signals that actually get through.

This gate mechanism is affected by a number of factors, the most important of which concern the pattern of nerve impulses that reach the spinal cord from the rest of the body, and nerve impulses generated by the brain itself. Sometimes the pattern of nerve impulses reaching the spinal gate can by altered by other forms of physical stimulation such as rubbing and massaging a painful area, applying electrical stimulation (e.g., TENS), applying extremes of temperature (e.g., either heat or cold), or putting needles into the body (e.g., acupuncture, trigger point injections). It is also important to realize that certain mental activities, taking place in the brain, can also result in nerve stimulation that can close the spinal gate.

ROLE OF ENDORPHINSThe term endorphin refers to a class of chemicals, which are produced in the brain, and serve an important role in the experience of pain. These chemicals act to


reduce pain in a way that is very similar to morphine and other opiates. In fact, the very word "endorphin" means an endogenous or internally produced, morphine-like substance. These endorphins act on specific receptor sites on special nerve cells deep within the brain. These receptor sites function like a lock which, when turned, generate nerve impulses that block pain. The endorphins act as a key turning the lock. Morphine and all the other opiates have a similar chemical structure and can also serve as keys to turn the lock.

What this means is that the more endorphins that are produced by the brain, the less pain you feel. However, if the locks (receptor sites) are already filled by the narcotics you’re taking, there may not be any need for endorphins. The following are some situations and conditions that are thought to stimulate endorphin production.

1. Emergency situations requiring the person to perform physical actions despite pain and injury.

2. Intense physical activity. 3. Moderate physical activity over an extended period of time can also increase

the supply of endorphins.

GENERAL RULES FOR SURGERYSurgery can relieve pain, restore function, and return a person to employment. Its potential to satisfactorily repair a damaged joint increases year by year. But surgery is expensive and painful, is associated with a long recovery period, keeps you away from activities during the period of convalescence, and may not be successful. The joint might be worse afterward. Surgery can even kill you or paralyze you, although this is rare. The decision to undergo surgery is one that you will make with your doctor. It's a major step, and you want to make the right decision. Here are some guidelines to help you sort out the issues.

Total Joint ReplacementFor individuals with severe damage to hips or knees, total joint replacement can mean the difference between being dependent on others and independent life at home or in the community. Such procedures are performed by orthopedic surgeons with special training in joint replacement. The damaged parts of the joints are replaced with metal or plastic components. These parts are attached to the bone with glue or by a careful tight fit. Some people with RA will benefit from replacement of other joints and from other types of surgery for hand and foot problems caused by the disease. People with early rheumatoid arthritis, however,


should be placed on a program of medications and therapy before surgery is considered as a form of treatment.

Surgery For Arthritis Is Seldom Urgent With only a few exceptions, a delay of days, weeks, or even months makes relatively little difference with surgery for arthritis. If the operation is successful, you will still have the good results to enjoy; if the operation is unsuccessful, you will have delayed the pain and expense by waiting. You have plenty of time for a second opinion, or a third. You can watch your condition to see if it goes away by itself or perhaps stabilizes at an acceptable level. So take your time. Rare exceptions to this rule include bone conditions causing nerve pressure, a bacterial infection in the bone or joint, or a rupture of the tendons.

Not All Surgeons Are Equal Generally, you will want an orthopedic or hand surgeon to perform any operations on your joints that may be required. You will also want a surgeon who does a lot of joint operations and is up-to-date on the latest techniques. Surgery is a rapidly changing field, and familiarity with the most recent advances leads to better results. A surgeon who performs the operation only once or twice a year is not likely to have the same level of skill as a surgeon who does the operation weekly. As a dividend, you will usually find that the busy joint surgeon is more conservative in his or her recommendation for an operation. It's not at all uncommon for a good orthopedic surgeon to state candidly that the condition for which the operation is being considered is not likely to respond to surgical treatment—and then you will be spared an unsuccessful operation.

Not All Operations Are Equal Total hip replacement and total knee replacement are very fine operations; almost all patients receive some benefit from them. On the other hand, certain procedures, such as tendon operations on the small joints of the hand or most kinds of back surgery, are far less predictable. Before you decide to have either of the latter two kinds of operation, you will want to find out how likely you are to derive benefit from the recommended operation.

Best Results Are Achieved When Problems Are Localized Treatment with medications is often best for a widespread problem. On the other hand, if the problem is localized, say in one knee, then surgery is likely to be a good, targeted approach to the problem. If a large number of joints are involved, surgery may be impractical. For example, the lower extremities consist of eight major weight-bearing areas: the two forefeet, the ankles, the knees, and the hips. If


any one of these areas is limiting walking, surgery may be a wise move. But if all eight areas are bad, then fixing one joint without providing relief to the other seven will not translate into function and increased activity. Be realistic. Ask how much better off you would be if the area of a proposed operation were entirely well. If the answer is, "Not much,” then surgery may not be advisable.

Best Results Are Achieved In Treatment Of Large JointsJoints are complicated structures and scarring after surgery can result in stiffness, particularly if the surface area of the joint is small. The best surgical procedures repair large joints, such as the hip and the knee. Results in these areas are usually predictably good. With the smaller joints, sophisticated repair techniques sometimes don't improve function significantly and should be approached with caution. Usually problems with smaller joints are also problems that involve many joints, which again complicates the surgical approach.

The decision to have surgery is a major one. It is not a decision to be made quickly without good reasons. Joint surgery can offer several benefits:

Relief of pain is the most important benefit of joint surgery. Many people with arthritis have constant pain. Some of this pain can be relieved by rest, heat and cold treatments, exercise, splints, and medication. When these therapies don't lessen the pain, surgery may be considered.

Improved movement and use of a joint are also important benefits of joint surgery. Continuous inflammation and the wearing away of bone and cartilage can cause joints, tendons, and ligaments to become damaged or pulled out of place. Losing the use of a joint, such as a hip, knee, hand, elbow or shoulder, can seriously hamper a person's activities. When this happens, surgery to replace or stabilize the joint may be suggested.

Some types of surgery lead to an improvement in the look of deformed joints, especially in the hand.

WHAT TO CONSIDER BEFORE HAVING SURGERYDon't be shy about asking lots of questions of your surgeon, including information on his or her success record with the particular procedure. Before you decide to have surgery, be sure to learn at least the following:

What operation is being suggested What the alternatives are


What the risks are What is involved in the recovery process

As you consider whether or not to have surgery, keep in mind that every person's needs are different. Your doctor may inform you that surgery won't give you the results you want. If your doctor thinks that surgery can help you, there are still many things you need to know.

If you have serious problems with your lungs or heart disease, the strain of some types of surgery may be too much for you. Before any kind of surgery, it's important to have other health problems under control.

In addition, any type of bacterial infection must be cleared up before surgery. One possible problem after joint surgery is infection, which can spread from one part of the body to another through the bloodstream.

Occasionally people develop blood clots in their legs or arms after surgery. The risk of this may be decreased by using blood-thinning drugs. Discuss this and other potential problems with your surgeon.

Being overweight may put extra stress on the heart and lungs. Also, if the surgery is on a weight-bearing joint (like a hip or knee), recovery of the joint may be slower. Excess weight puts added strain on the joint and makes it harder to do the exercises needed to make the joint stronger after surgery.

Before you decide on surgery, you must be aware that you have to follow a strict treatment plan after the operation. It's important to realize that the operation is only the first step toward restoring joint function.

The amount of work you put into the recovery process often makes the difference between success and failure. Your doctor's orders regarding medication, joint protection, rest, exercise, physical therapy, and the possible use of splints must be followed very carefully. If you don't believe you can follow through on all your prescribed care, then surgery may not be the best treatment for you.

WORKING WITH YOUR DOCTOR & GETTING A SECOND OPINIONJoint surgery is not for everybody. Even if your doctor and surgeon determine your condition would be improved by surgery, the decision to have the operation is still up to you. You need to weigh your options and understand what the surgery will involve—before, during, and after surgery, and over the months of physical therapy. It will require patience and the willingness to follow through with physical therapy. Your commitment is the key ingredient in the success of joint surgery.


Of course, you will have support in this undertaking. Doctors, nurses, physical and occupational therapists, and social workers are part of the team that will work to make the surgery a success. Your family and friends are also members of the team. Look to them for emotional support and for assistance during your recovery. But the most important team member is you.

If you're not sure about having surgery, ask for a second opinion from another doctor. Ask your doctor to recommend a surgeon who has experience with arthritis. Sign a release form and ask that your doctor’s office send your medical records and x-rays to the consulting surgeon. Consider the advice of all your doctors carefully. Sometimes it may be hard to remember what you want to ask the doctor unless you write down your questions. You might want to refer to the list we’ve provided of questions you may want to ask about the surgery (page 15).

TYPES OF SURGERY Joint Replacement This is the most important orthopedic surgical procedure for arthritis. The joint is removed and replaced entirely by an artificial joint. The cartilage is replaced by long wearing plastics such as Teflon, the bone is replaced by titanium, and the artificial joint is embedded in the ends of the bone on either side by a marvelous cement called methyl methacralate. This bone cement made possible the new era in joint surgery by providing a way to anchor the artificial joint to the bones. The hip was the first joint to be replaced.

Total Hip Replacement In the hands of an experienced surgeon, this is an excellent operation. Pain is almost totally relieved, and function is greatly improved. The present artificial hip is estimated to last 10 to 15 years, and newer models are expected to last longer as design problems are overcome. The failure rate is only one or two percent, but these patients may have infections or even have to have the artificial hip removed. It is true that some patients receiving artificial hips have to have a replacement for the replacement; it is also true that the final result usually has been satisfactory. Recently a new type of total hip operation has been developed that works by allowing bony in-growth into the artificial joint; it does not require cement.

Knee ReplacementThe knee is a complicated hinge joint with a requirement for sideways stability. This has made it more difficult to construct an appropriate replacement joint, since the joint must move freely in the hinge direction but must strongly resist sideways


force. The ball and socket joint of the hip poses easier engineering problems. Techniques of knee replacement have been greatly refined over the last several years.

Other Types of Joint Replacement SurgeryAnkle replacements remain less frequently used. Shoulder replacements have become quite good. Operations to replace the small joints of the fingers are widely practiced, but the outcome has not been uniformly satisfactory. One of the problems with present operations for the small joints of the hands is that appearance may be considerably improved by the straightening of deformed fingers but the ability to use the hand may not be greatly changed.

SynovectomySynovectomy is the removal of diseased synovium. This popular operation results in a reduction of the swelling of synovitis and presumably less enzymatic damage to the joint because the inflamed tissue mass has been reduced. Unfortunately joint stiffness is often experienced after the synovectomy and the inflamed tissue frequently grows back. There has been a long-standing argument about whether synovectomy should be done early or late, or never, in rheumatoid arthritis, with some doctors holding each position. In other words, the effects of synovectomy are not so dramatic that people can’t argue about them. There should be a special reason for this operation, such as worsening of a single joint when all other joints are in control, or the hope of avoiding the use of a hazardous drug.

ResectionSome older operations sound a bit strange, and this is the case with resection procedures. Here, bones are just cut away and removed. This may sound as though it wouldn’t be very helpful, but often it is. Resection of the metatarsal heads in the forefoot, for example, can relieve pain and restore the ability to walk. Similar operations may be done in the distal ulna, the bone on the outside of the wrist. Bunions and other protuberances can be removed. While this type of surgery is not elegant in concept, it can be very useful.

FusionsAn operation to unite two bones is termed a fusion. Such operations are useful to stabilize joints; the fusion provides a platform for movement and prevents pain in the fused area. The wrist and ankle are the joints where this procedure is most frequently used; fusion of the back or part of the neck is also performed on occasion. A successful fusion, limiting all motion, stops pain. But in the area that is fused, flexibility is lost. Usually a fusion places additional strain on nearby


joints that are called on to take over the flexibility functions. Fusion doesn’t always work, and nonunion can occur. These operations are useful, however, in certain situations.

Neurological OperationsThere can be pressure on nerves out in the limbs. An example is carpal tunnel syndrome, where there is pressure on the nerve passing over the front of the wrist resulting in pain and tingling in the fingers. This pressure can be effectively eliminated by surgery, and surgery should be considered if rest and/or injection do not result in disappearance of the syndrome within a few weeks. Other problems such as Morton’s neuroma, can also cause peripheral pain. Here, an injury has caused the nerve fibers to grow into a little ball and to transmit pain signals all the time. If this bundle of nerves is removed, the pain is eliminated and a good result obtained. So while we can’t really operate to repair nerves, we can either remove the structures that are pressing on them or remove the area that is sending the abnormal signals.

VIDEO: “Rebuilding Arthritic Hands”


GATE OPENERS

1. Physical Factors Extent of injury/disease Readiness of nervous system

to receive pain signals Inappropriate activity level

2. Thought-related Factors Focusing on the pain Boredom Non-adaptive attitudes

3. Emotional Factors Tension Negative emotional arousal

(i.e., stress)

GATE CLOSERS

1. Physical Factors Medications (opioids, NSAIDS) Stimulation (heat, massage,

acupuncture) Surgery Reduced muscle tension or

arousal

2. Thought-related Factors Distractions (diverting your

attention away from the pain) Humor and positive attitudes

3. Action-related Factors Utilizing active coping skills Increased feelings of control

WHAT TO EXPECT FOLLOWING SURGERY

SESSION 4: Neurophysiology of Pain; Surgical Interventions

Gate

Site of Injury

Ascending Spinal Nerves

Sensation Center

Gate Control Theory

11

Depending on the type of surgery, your doctor will usually prescribe a period of rest, physical therapy, and limited activity. Before you undergo surgery, make sure your household can be arranged so that your full recovery is possible. You may need days or weeks of rest. In addition, you may need to use splints, a cane, a walker, a wheelchair, or crutches before you are able to perform your usual tasks. Talk with your doctor about any short-term limitations and what you can expect during the recovery period. You may also be referred to an occupational therapist for advice on how to do your daily activities in ways that are safe for your joints.

If your surgery involved your hand(s) or arm(s), you will most likely be able to get up the first day after the operation. If it involved one or both legs, how soon you are allowed out of bed will depend on the surgery. Often, you will be able to get up the first day after surgery, but it may be longer. Once your doctor has given permission for you to get up, you will begin to feel better the more you move around.

As soon as you're able and depending on the type of surgery you've had, you will begin physical therapy consisting of various exercises. You must dedicate yourself to this program and be prepared to work hard. If you don't, your repaired joint may be less useful than it could be.

Some pain is common during the early stages of physical therapy. This pain usually comes from the muscles, not the joint. Some of your muscles have not been used much or may have been working in abnormal ways to protect a sore joint. Some muscles may have been cut and stitched during surgery. It is important to realize that muscles strengthen in response to exercise. An exercise that hurts today may hurt a little less tomorrow. You will see improvements in range of motion, along with decreased pain, as time goes on.

You will have to work hard for the first few weeks after surgery to achieve range of motion, and a little less so for several months after that to regain strength. As time goes on, keeping up with your physical therapy requires dedication. You may find that you're bored with the exercises, and you may be tempted to slack off. Don't! Remember that it takes time, but the rewards can be great. You should start to see some encouraging results, such as the ability to perform a task that was too painful to do before surgery. The combined efforts of your doctors, nurses, therapists, and most important, yourself, are essential to success.


QUESTIONS YOU MAY WANT TO ASK ABOUT THE SURGERY

1. What other kinds of treatment may I have other than surgery?2. How successful will these treatments be?3. Can you explain the operation?4. Do you have written materials or videotapes on this surgery that I can

review?5. How long will the surgery take?6. Can surgery be performed as an outpatient?7. What risks are involved in the surgery? How likely are they?8. Are blood transfusions necessary, and if so, can I donate my own blood?9. What type of anesthesia will I have? What are the risks?10. How much improvement can I expect from the surgery?11. Will more surgery be necessary?12. If surgery is chosen, will you contact my family doctor? Will he or she be

involved in my hospital stay? In what way?13. Are you Board Certified, and do you have a special interest in arthritis

surgery?14. What is your experience doing this type of surgery?15. Would you give me the name of another person who has undergone this

surgery who would talk to me about it?16. Is an exercise program recommended before and after the operation?17. Must I stop any of my medications before surgery?18. What happens if I delay surgery?19. What are the risks if I don't have the surgery?


HOW TO PREPARE FOR SURGERY

Preparing mentally and physically for surgery is an important step toward a successful result. People who understand and are knowledgeable about the process have swifter recoveries and fewer problems.

If you smoke, you should stop prior to surgery if you can.

Diet is an important factor in general health and becomes especially important in times of stress, such as around the time of surgery. It is best to eat foods that are rich in nutrients prior to surgery and during the entire first year after surgery. Vitamin C is especially important because it enhances the healing process.

Do not take aspirin or aspirin-like medications for three days before surgery. These medications interfere with blood clotting.

If you take cortisone, prednisone, or any steroid medication, you must tell your surgeon before the operation. These medications should not be stopped before or after surgery.


Name ______________________________ Date _______________________

QUESTIONS YOU MAY WANT TO ASK AFTER SURGERY

1. How long will I stay in the hospital?2. How much pain will there be? Will I receive medication for it? What kind of

pain is normal to expect? How long will this pain last?3. How long do I have to stay in bed?4. When do I start physical therapy? Will I need home or outpatient therapy?5. May I review written materials or videotapes concerning this phase of my

care?6. Are physical therapy, occupational therapy, and home health care covered

by insurance? (You may need to address this question with your insurance company.)

7. Will I need to arrange for special help at home? If so, for how long? Is it covered by my insurance?

8. What medications will I need at home, and how long will I need to take them?

9. What limits will there be on my activities, e.g., driving, using the toilet, climbing stairs, bending, eating, sex?

10. How often will I have follow-up visits with you? Are they covered by insurance? Are they included in the cost of the surgery?


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