A primer on the basics of this ever-growing subspecialty.
June, 2002
Bill Meltzer, Associate Editor

It is estimated that one person in three suffers with some form of chronic pain, affecting an estimated 86 million Americans. Nevertheless, until recently, pain was largely undertreated and widely misunderstood, even by many within the medical profession. This article will spell out the basics of chronic pain management.

Chronic vs. acute pain
How does chronic pain differ from acute pain? Acute pain follows injury to the body-including surgery-and disappears as the body heals. According to the American Pain Society, acute pain is often, but not always, associated with objective physical signs of autonomic nervous system activity. Conversely, chronic pain is not typically accompanied by signs of sympathetic nervous system arousal. The lack of overt signs of pain may prompt the conclusion that the patient does not "look" like he or she is in pain; consequently, direct causes may be more difficult to determine.

Says Harold Weintraub, MD, an anesthesiologist based in Miami, Fla., "The reason why pain management has become a specialized field is that chronic pain has traditionally been undertreated. And the reason why it has been undertreated is that chronic pain can be harder to pin down. As a working definition, you can say that chronic pain involves persistent pain, but it isn't necessarily constant pain. Rather, it is better defined as episodic pain, and the episodes can fluctuate in their regularity and severity. Another problem for clinicians is that chronic pain can be somewhat unpredictable-for example, it may or may not occur after waking up or exercising. Finally, it may or may not be localized. Chronic pain can occur in a single body part or body region or multiple body regions and organ systems."

What causes chronic pain?
Apart from physiological factors such as cancer-related pain, rheumatoid arthritis and fibromyalgia, there are non-physical factors that can contribute to chronic pain. Explains Shashir Dhruva, MD, medical director of the Therapeutic Pain Management Medical Clinic in Redding, Calif., "Chronic pain is related to aspects of both physical and mental health. Factors such as stress and anxiety can trigger or contribute to chronic pain. Also, people process pain differently and have widely different levels of tolerance. Furthermore, a patient's age, lifestyle, and physiological processes can all be contributing factors."

Chronic pain can also be an after-effect of surgery. It may initially begin at the same time as the expected post-operative acute pain, but chronic pain continues beyond the normal time expected for resolution of the problem. Instead, the pain persists and recurs. Common outpatient procedure patients with a higher-than-average risk of post-operative chronic pain would include inguinal hernia patients and gallbladder patients. Inpatient cases that may require a pain specialist include limb amputations and major breast surgery.

According to experts, there are a variety of pre-op, intraoperative, and post-op factors that can be predictive of subsequent chronic pain.

Pre-operative factors that may predict subsequent chronic pain include if the patient has experienced moderate to severe pain prior to the surgery lasting over one month, if the patient is in for repeat surgery, if the case has been referred as a worker's comp-related case, or if the patient is psychologically fragile (for example, if the patient has been under a high level of stress, exacerbated by having to have surgery).

Intraoperative factors may include whether the surgery involves working near nerves (increasing the possibility of post-op complications) and in some cases, whether the patient has had anesthesia complications.

Post-operative factors may include unusually severe acute pain or acute pain accompanied by episodic flair-ups, failure of standard post-op medications to successfully treat the patient's pain, and post-op psychological factors, such as anxiety and depression. For cancer patients, radiation and chemotherapy treatments can be predictive of chronic pain, as well.

What does a pain management specialist do?
After a chronic pain patient is referred to a pain management specialist, the physician will interview and assess the patient. As part of the process, the patient is asked to clarify his or her desired and/or acceptable outcome.

Says Venu Shah, MD, San Jose, Calif., "It's absolutely essential that the treating physician and the patient have a mutual understanding of the goals of treatment. Pain management is a specialty in which differing goals can greatly affect patient satisfaction and the eventual success of treatment. For subsequent treatment to proceed, mutual and realistic goals need to be established."

The patient is assessed along both physical and psychological baselines. Says Dr. Shah, "There are the so-called 4 A's that you look for: Analgesia, Activity (such as daily exercise), Adverse effects of potential drug treatments, and Aberrant behavior."

Measuring tools called pain analog scales are used to assess the physical ramifications of chronic pain. Use of the pain analog scales before and after treatment "quantifies" the patient's pain level and gives a baseline from which progress (or lack thereof) can be measured. As with acute pain, the 1-10 scale established by the Veteran's Administration can be used to quantify chronic pain. Says Dr. Shah, "If patients have chronic pain episodes that rate 4 or higher, medical intervention is appropriate."

If, after physical and psychological assessment, the patient is accepted as a treatment candidate, the physician will consider the following factors in formulating a treatment plan:

Primary pre-referral diagnosis: The diagnosis is double-checked to see if it is supported by medical history, physical findings during assessment, and the results of any tests. These should be directed to answering the question of whether it is medically justified for the patient to be seeing a pain management specialist and if other, more standard forms of pain relief have been tried with due diligence.

Assessment: The caregiver's direct assessment on the patient's physical and psychological status.

Compliance ability: The physician will evaluate if the patient is likely to understand goals and comply with instructions.

Medical records: This includes documentation of all patient office visits and consultations; all prescriptions including date, types of medication, and quantity prescribed; therapeutic and diagnostic procedures performed; and laboratory results.

Objectives for treatment: The physician will consider whether the treatment objectives are measurable and reasonable.

During treatment, each patient has a chance to review his or her progress on a regular basis. Patients are asked if they are satisfied with the treatment to date and if there has been any change, positive or negative, subtle or substantial since the last assessment. The plan is continued or altered accordingly.

Common treatment methods for chronic pain
There are a variety of potential treatment options for the chronic pain patient. These are some of the most common. Note that some are used for different types of chronic pain and are not considered alternative options if one course of treatment is deemed inappropriate or does not work.

Opioid treatments
This is an increasingly common and accepted way to treat chronic pain, but it is still controversial in the general medical community. According to Dr. Weintraub, if chronic pain limits function, opioids may help improve function. Studies have shown that chronic pain for non-cancer patients can be effectively managed with opioids. However, there are fears about regulatory sanctions, abuse potential and side effects.

Says Dr. Weintraub, "For many patients, opioids are the simplest and most effective way to treat their pain. In some cases, it's the only treatment option that provides significant relief for chronic pain. If patients are assessed by accepted standards of pain management-in other words, they have a legitimate chronic pain condition and they meet the psychological profile-there's no reason not to consider opioids a viable option."

Before prescribing opioids, the caregiver must be aware of several regulatory issues. To legally use this treatment method, the physician must be licensed by State medical authorities and registered with the DEA; these requirements are necessary to prescribe any controlled substance.

The source of controversy behind opioid treatments, of course, is their abuse potential. Says Dr. Shah, "Opioid abuse is of course a serious issue, and there is a tremendous responsibility for the caregiver to consider the abuse potential. Patients with psychological problems and especially those with histories of drug abuse should raise caution in cases in which opioids may be indicated from a strictly clinical standpoint. But what also concerns me is the tendency of some physicians to focus only on the abuse potential of opioids, without respecting their legitimate analgesia potential. I believe strongly in caution with opioids, but sometimes we cross the line between caution and fear."

Dr. Weintraub adds, "There is also the issue of side-effects. It should almost go without saying that side-effects will vary by patient, intake, and the specific medication you use, but the common side-effects of opioids are sedation and constipation." Dr. Weintraub says that with chronic pain, opioid side effects are usually comparable to side effects during opioid therapy for cancer pain. Neuropsychological side effects (such sedation) can be managed effectively using such measures as dosage reduction, change of opioid agent, addition of psychostimulant drugs, elimination of other drugs or conditions that may contribute to side effects. Constipation can be managed with a stepwise approach that includes an increase in fiber and fluids, adding stimulant laxatives (for example senna or bisacodyl) as needed, with or without concurrent softening agent.

Epidural and Transdermal Treatments
A major category of chronic pain treatments falls under a rough heading of injections. These are some of the more common types of injection-related treatments.

Epidural steroid injections. These are used widely with treating chronic lower back pain and leg pain. Epidural injections can also be given for overall analgesia. Steroids are injected directly into the problem area to decrease inflammation. Says Dr. Shah, "Lay people hear 'steroids' and assume this a way to try to build strength. What it really is a way to reduce pain and inflammation. It's a fairly conservative approach. Rebuilding strength is an ambitious goal that could be set if the treatment is successful in restoring daily mobility with manageable pain."

According to experts, the advantages of epidural treatments are that they are an established technique with a track record of providing varying degrees of chronic pain relief. The disadvantages are, as with any type of injection, there are potential risks any time the skin is broken. The injections may work for a period of time and then stop. Finally, some patients are afraid of receiving epidural injections and, as such, may not be a good psychological "fit" for the treatment option.

Nerve blocks. These encompass various different types of injections of long-acting anesthetic agents. Says Dr. Shah, "Nerve blocks are a somewhat more aggressive form of chronic pain therapy, but they are also very well-established and highly effective for many patients. The risks of nerve blocks are somewhat higher than giving an epidural-there is risk of nerve damage, for one." The following are some of the more common types of nerve blocks.

Stellate ganglion blocks: This injection occurs in the lower neck in front of the spine. These blocks are used to treat facial, arm and hand pain.

Lumbar blocks: Injections into the front of the spine in the lower back. They are used to treat leg and foot pain.

Sacral blocks: Injections just above or below the base of the spine. They are used to treat pain in the pelvic area.

Celiac plexus blocks: These injections target nerves located in the abdominal region. These are primarily used to treat cancer pain in this area but may also be used for patients who experience chronic pain after a hernia.

Intercostal blocks: These are injections into the chest wall used to treat pain in the sternum.

Trigger Point Injections. These are injections right into the muscle, designed to relieve muscle spasms and relax the muscle. Says Dr. Shah, "This method is common in cases where chronic muscle pain may be preventing someone from working or going about their daily routine." Along with the injections, patients are usually given exercises to do at home and work with a physical therapist.

Surgical Options
For some patients, the only viable treatment option is to perform an outpatient implantation of a pain pump. Says Dr. Dhruva, "If the patient has a well-documented pain condition that has not responded to oral or transdermal medications and also fits the proper psychological profile, he or she may be a candidate for an implantable device." Accepted patients will undergo a trial run with the medication that will be infused by the pump. The specific agent that is used can vary, but they are often the same types of medications used in other treatments. If all goes well with the trial, they will undergo a procedure that takes about 45 minutes to an hour."

The procedure involves two incisions in the abdominal area; one where the pump itself is implanted and a second in the lower back, where a catheter is inserted. The pump is about the size of a hockey puck. The infusion pumps come in two varieties-programmable and non-programmable. Programmable pumps, which are considerably more expensive but offer great flexibility in managing concentration and amount of the medication delivered, run on batteries and must be replaced after the battery runs out-typically a four to seven year period. The non-programmable pumps run on gas (such as freon), which does not need to be replenished. However, once a patient develops tolerance to the medication, the pump needs to be refilled with another agent to provide a comparable level of relief.

According to experts, implantable pumps can dramatically improve the quality of life for chronic pain patients, but as they are invasive, permanent, and expensive, they are a last resort. The benefits of the implantables are that they provide continuous and consistent pain relief, reduced side-effects, and long-term cost-effectiveness (over a period of years, the costs of oral medications add up). The drawbacks are the risk of post-operative problems (infection, accidental trauma), discomfort from the device itself, and the still-extant possibility of reaction to the medication.

The treatments described above encompass only a fraction of the drug-related treatments that (there are also an array of non-drug, as well as less widely accepted , so-called "alternative" therapies). Increasingly, says Dr. Weintraub, the field is moving from a subspecialization of anesthesiology to a multi-disciplimary type of medicine. Concludes Dr. Weintraub, "I think it's fair to say that as well as anesthesiology, pain management incorporates elements of neurology, psychiatry, physical and occupational therapy, industrial medicine, and orthopedic medicine. I see pain management as one of the most dynamic of all medical specialties."

Copyright Herrin Publishing Partners, 2002