|
Overview
| Making the Diagnosis
| Getting Help
| Fast Facts
| Myths and Misconceptions
| Children
and Pain
Pain Definitions
| Medications
| Complementary
| Physical Therapy
| Psychology
|Surgery
Interventional Treatment — Injections and
Surgery
At one time, it was believed that all CRPS pain
was related to the sympathetic nervous system (that part of the nervous
system responsible for the regulation of functions such as sweating, body
temperature and blood flow). Thus, injections or surgery designed to disrupt
the function of those nerves and parts of the spinal cord that control
"sympathetic tone" were thought to be useful. This was based on the observations that such
procedures sometimes helped relieve CRPS pain and that patients often
displayed evidence of alterations in local body temperature, sweating, swelling,
and other evidence of "sympathetic" abnormalities.
Physicians now know that CRPS
patients may have abnormalities both in the function of this part of the nervous
system, in association with pain called "sympathetically maintained pain" or SMP,
as well as other parts ("sympathetically independent pain" or SIP). Injections
or surgery, therefore, may be directed to portions of the nervous system
responsible for either SMP or SIP or both. This represents a distinct departure
from former traditional thinking about the "interventional" (injections and
surgery) methods for treating CRPS. The traditional thinking was that techniques
designed to treat SMP, such as sympathetic blocks, were the only interventional
strategies available. We now know that this is incorrect; however, as in many
areas of medicine, new research and teaching has not yet caught up with many
regional practice patterns.
Interventional treatment can be divided into the following categories:
-
Sympathetic blockade
-
Somatosensory blockade
-
Surgical nerve decompression
-
Regional anesthesia blocks
-
Continuous infusion blocks
-
Neurolytic blocks
-
Spinal cord stimulation (SCS)
-
Peripheral nerve stimulation (PNS).
-
Intrathecal drug delivery (ITDD).
Sympathetic blockade.
There are numerous ways to chemically or surgically block transmission of nerve
impulses in the sympathetic nervous system. The most common is the use of a
local anesthetic, ideally injected by a well-trained medical specialist under
fluoroscopic guidance into the region of the stellate ganglion in the neck or
the lumbar sympathetic chain in the low back. These blocks may provide temporary
relief of CRPS pain and related symptoms. Response to the blocks
traditionally was thought to be an important piece of information for diagnosing CRPS;
however, there are many reasons why the blocks may fail, including:
-
Inadequate technique
on the part of the health care provider that fails to achieve a complete block.
-
Absence of SMP in any given patient or at any given stage of the disease.
-
Reliance on the patient's report
of pain relief, which may be influenced by multiple
psychosocial factors.
-
Poor record keeping by the doctor.
There are other techniques that can achieve sympathetic blockade, including
injection into other areas of the body or applications of new technology, such
as radiofrequency (RF) probes, and the use of a
wide variety of other injected drugs. Depending on where you live, such
techniques may not be available in your area. This fact has created difficulty in
gathering meaningful treatment outcome data about sympathetic blockade and is
one of the reasons why there remains confusion in the medical and insurance
communities about the place for sympathetic blockade in the evaluation and
treatment of CRPS.
One area of great concern is the place for
permanent blocks in parts of the sympathetic nervous system. Permanent blocks
can be achieved by the injection of chemicals, such as alcohol or phenol, by
improper use of RF technology, or by surgical cutting of sympathetic nerves or
ganglions. Many patients who have had these procedures get temporary relief of
pain, only to be replaced months later by recurrence of pain (called
"deafferentation" pain) that is just as bad or worse than the original pain. For
this reason permanent blocks (also known as "neuroablative" procedures) are
generally best limited to end-of-life care, when the patient's life
is expected to end before the appearance of such deafferentation pain.
Somatosensory blocks
At times, damage to other parts of the nervous system, particularly nerves in
the head, neck, face and extremities, may cause pain. Blockade of these nerves
may provide a clinician with information about whether or not SIP
(sympathetically independent pain) is present and can help direct medical
treatment. An example is a patient who has CRPS in association with carpal
tunnel syndrome caused by compression of the median nerve in the wrist. All the
rules about blocks, including the dangers of neuroablative procedures, apply to
somatosensory as well as sympathetic nerve blockade.
Surgical nerve decompression
Surgical relief of compressed nerves may provide pain relief in patients with
CRPS II. Most experts believe that any surgical procedures in an area of the body
affected by
CRPS, including those done on or around somatosensory nerves, also require the
use
of regional sympathetic blockade because CRPS may get
worse if such blockade is not part of the surgical plan.
Regional anesthesia blockade
There are a variety of ways to produce regional anesthesia of somatosensory
nerves and/or regional sympathetic blockade, including the injection of drugs
and/or local anesthetics into veins or into the epidural space of the spine and
the use of radiofrequency (RF) or surgical interruption of nerves. These
techniques are often used when simpler procedures have failed to produce any
lasting relief of symptoms, and should only be done by very qualified
specialists (almost always anesthesiologists with special training in pain
management). The long-term value of these techniques is unknown and there is
considerable differences in availability depending on where you live and in types of procedures
used. Neuroablative (permanent) blocks are generally discouraged except in
end-of-life care, as discussed above.
Continuous infusion blocks
Something to consider when temporary blocks fail is the continuous infusion of
local anesthetics into various parts of the body. This includes areas where
nerves may be found together in "nerve plexuses" or in the epidural space of the
spine. There is some evidence for the usefulness of these techniques, but they
are usually available only in highly specialized pain treatment centers. When
available, they are generally preferred before trying even riskier techniques
(to be discussed below).
Neurolytic (neuroablative) blocks
This refers to permanent blocks in portions of the somatosensory or sympathetic
nerve system, and has already been discussed in previous sections. Surgical
interruption of sympathetic nerves (sympathectomy) was once very popular, but
has now fallen out of favor. It is generally agreed that all neurolytic
procedures should be limited to end-of-life care; however, it still continues to be a method of treatment
in many parts of the world. This may be because of the
sense of desperation that CRPS patients may bring to their physicians and the
lack of knowledge about poor long-term outcomes with these procedures.
Spinal cord stimulation (SCS)
SCS is one of the more promising techniques available for the treatment of CRPS.
Once felt to be only a "last resort" in treatment (and still considered so by
many insurance companies), newer information suggests that when performed by an
experienced and specially trained surgeon, SCS can be of considerable help in CRPS. Outcomes vary with the skill and experience
of the medical team, and great care should be taken in choosing a practitioner
who offers this therapy. SCS is generally first offered on a temporary basis
and, if successful, is then used on a more permanent basis through surgery.
Risks include equipment failure, infection, and injury to the spinal cord. The
long-term (over years) outcomes of SCS await further studies from multiple
specialty centers.
Peripheral nerve stimulation (PNS)
Peripheral nerve stimulators have been placed near the spinal cord or further
away in the limbs, usually when severe pain is present in the territory (or
distribution) of a somatosensory nerve. This may or may not be accompanied by
signs of CRPS in more distant areas. PNS is a highly specialized area that is
available in few parts of the country and there is limited information about its
usefulness.
Intrathecal drug delivery (ITDD)
A variety of drugs have been injected into different parts of the spinal canal
for the treatment of severe pain, including pain related to cancer and CRPS. Only morphine is
approved by the U.S. Food and Drug Administration for this purpose, but numerous other drugs have been used
"off label." The technique is most often used in patients who have had good
responses to the use of morphine-like drugs (opioids) taken by mouth, who can no
longer use them because of intolerable side effects that can develop as
tolerance to the pain-relieving effects of the drug occurs and progressively
higher doses are required to get the same pain relief. Most specialists believe
ITDD to be a truly "last resort" treatment for CRPS, when all other techniques
have failed, because of the high rate of complications, high maintenance costs
and general unavailability in the medical community.
Overview
| Making the Diagnosis
| Getting Help
| Fast Facts
| Myths and Misconceptions
| Children
and Pain
Pain Definitions
| Medications
| Complementary
| Physical Therapy
| Psychology
|Surgery
|
