NEW YORKIn recent years, the practicing anesthesiologist has
become more involved in the management of pain and has to be aware of
the increasing number of treatments available, said Carol A.
Warfield, MD, chief, Division of Pain Services, Beth Israel Deaconess
Speaking at the Third Conference on Pain Management and Chemical
Dependency, Dr. Warfield addressed some of the more common problems
seen in a multidisciplinary pain management center, including back,
neck, neuropathic, and cancer-related pain. The conference was
sponsored by the American Pain Society, the National Institute on
Drug Abuse (NIDA), Beth Israel Medical Center, New York, and others.
Lower Back Pain
Lower back pain affects about four out of five people at some point
in life and may be addressed through many treatment options, she
said. Of the injection therapies, the most common is the epidural
In discogenic disease, these injections will not only reduce
the edema, but also reduce the patients pain, Dr.
Warfield said. Epidural steroid injections are most effective in
patients with acute radiculop-athy and those with acute exacerbations
of chronic pain. Unfortunately, patients who have had previous
back surgery do not do as well, she added.
Use of an epi-duroscope offers the advantage of allowing the
physician to visualize adhesions during an epidural injection.
Unfortunately, the data have not supported that its use provides any
better relief than a blind epidural injection. However, when
the role of the epiduroscope is further defined, it may serve as a
diagnostic measure, defining situations in which surgical or other
interventional techniques should be used, Dr. Warfield said.
The selective nerve root block also allows the physician to identify
the correct nerve root and can help identify which patients may be
amenable to interven-tional surgical procedures, she said.
In the discogram, another technique for identifying the inflamed
nerve root, a saline injection may mimic the patients usual
pain. It is especially useful for the patient with axial low back
pain, which is common among chronic back pain sufferers.
Many patients have had previous surgery that relieved the radicular
pain component in their leg, but are left with the axial low back
pain without radiation to the leg. The discogram technique will
help us determine which disks are involved and tell the surgeon
whether the patient is a candidate for spinal fusion to prevent
further irritation at the level of the disk, Dr. Warfield
Facet syndrome is a pain syndrome occurring particularly
postsurgically. It is a difficult diagnosis to make because
there are no diagnostic techniques that are pathognomonic for
it, Dr. Warfield noted. A past study looking for predictive
factors found that patients who had positive x-rays, CT scans, or
MRIs, and had awakenings from pain, tenderness over a facet joint,
and absence of positive straight leg raising, were the patients most
likely to benefit from facet blocks.
Although most patients experience short-term relief from a series of
facet injections, many do not get long-term relief, she said. A newer
radiofrequency denervation technique offers longer term relief. The
response has been generally good, although there are varying study
Many patients who have initial pain relief with this technique
go on to experience long-term or permanent relief, Dr. Warfield said.
In chronic regional pain syndrome (CRPS), patients will typically
have burning and heightened aesthetic pain related to an over- or
understimula-tion of the sympathetic nervous system. These
patients can be very dysfunctional, with severe hyperpathic
pain, Dr. Warfield said. CRPS type I, also called RSD (reflex
sympathetic dystrophy), is not associated with major nerve trauma in
contrast to CRPS type II, or causalgia, which does involve major
nerve trauma. Among tests for CRPS are sympathetic blocks, she said.
A series of such injections is usually enough to provide adequate
In some circumstances, radiofrequency lesioning (or denervation) can
help patients with RSD. Radiofrequency denervation may also be
effective for those with intractable pain from vascular disease or
other vascular problems in the lower extremities. Regional IV
infusions of vasodilators have also been reported to offer long-term
relief to some patients with hypersympathetic mediated pain
Regarding neuropathic pain, Dr. Warfield noted several innovative
techniques. Capsaicin (Zostrix), which depletes substance P from the
nerve endings, has been used to treat burning neuropathic pain.
Transcutaneous electrical nerve stimulation (TENS) has been
particularly useful in neuropathic pain.
Spinal Cord Stimulation
Spinal cord stimulation effected via an externally placed
transmitting device has been especially effective for patients with
failed back syndrome or previous laminectomy, particularly when the
patient has unilateral leg pain, Dr. Warfield said. The technique is
also useful for ischemic limb pain, CRPS, and some types of
neuropathic pain such as postamputation, spinal cord injuries, and
For patients who respond to spinal cord stimulation, this
can really be a miraculous relief for their chronic pain, Dr.
A few patients who require long-term opioid treatment but cannot
tolerate the intractable side effects of nausea and sedation may be
candidates for spinally administered opiates. In a study of more than
1,200 chronic pain cancer patients, only 1% fell into this category.
Catheters for epidural opiates can be internally or externally
implanted, giving patients the freedom to receive treatment at home.
Because endorphins are not the only neurotransmitters to mediate
pain, many non-opioid drugs may be helpful. For example, agonists of
serotonin, norepinephrine, GABA, and somatostatin can also be
injected to provide pain relief independent of the opioid system.
Patients tolerant to opioids or those with neuropathic pain can
benefit from injections of clonidine, the most common of these
non-opioid drugs, Dr. Warfield observed.
Rounding out the list of useful approaches in chronic pain settings,
Dr. Warfield included spinal alcohol blocks, other neurolytic blocks,
cryoanalgesia, and a few neurosurgical procedures. She concluded with
the reminder that proper patient evaluation is critical to correct