Unrealistic expectations are the most common causes of a “perception
of failure” after a procedure. Most nerve blocks are done for diagnostic
purposes as well as for treatment. We all hope that a single nerve block will
be able to take our pain away and allow us to go back to our normal lives.
Although this is occasionally true, it is not the rule, but the exception.
Most nerve blocks are performed with local anesthetics as well as steroids.
If you are to get any long-term benefits, this will occur as a consequence of
the steroids. The purpose of steroids is to decrease any chronic
swelling that may exist in the area. They normally begin to work immediately
after being injected. Nevertheless, in most patients, it will take 5 to 10 days
for the swelling to come down to the point where you will be able to tell a
difference. Steroids will only help if there is swelling to be treated.
If the problem is one of mechanical compression, you will get no benefit
from those steroids. As such, the steroids have a diagnostic purpose, where if
effective, they suggest an inflammatory component to the pain, and if
ineffective, they rule out inflammation as the main cause or component of the
problem. This is usually referred to as the “long-term benefit” of the
procedure.
In the case of local anesthetics, their goal is not only to
provide you with some relief of the pain during and after the procedure, but
they also have a crucial role in the diagnosis of your condition. There are
short-acting (1-2 hours) and long-acting (4-6 hours) local anesthetics. Most
will begin to work within15 to 20 minutes after injected. The duration will
depend on the type used (short- vs. Long-acting). It is of outmost importance
that patients and their family members keep tract of whether there was
immediate relief of the pain after the procedure, and for how long. They are
essential in providing diagnostic information to the physician. Normally, if
the patient does not obtain any relief of the pain for the duration of the
local anesthetic, this would suggest that the blocked nerve was not responsible
for the conduction of the painful stimulus. On the other hand, good relief of
the pain during the time that the numbing medicine is in effect, would be
interpreted as a success in having identified the nerve that is transmitting
the painful impulse, even if the pain returns when the local anesthetic wears
off. This is usually referred to as the “short-term benefit” of the
procedure.
It is therefore possible to get 100%
short-term relief of the pain, with 0% long-term relief. This would suggest
that even though the correct structure was blocked, the mechanism of the pain
does not involve an inflammatory component and therefore a different technique
will need to be applied to obtain longer lasting relief of the pain.
The above is only true if all blocks have
been performed under radiological guidance, where confirmation of needle placement
can be assessed. Otherwise, 0% short-term benefits from the procedure may be as
a consequence of a missed target.
Sadly, this information is not always given
to the patients, and even worse, in the case of diagnostic procedures performed
by Non-Pain Specialists, the patients are not followed after the procedure to
collect these results. The obvious problem being that a patient may not obtain
long-term benefit from the nerve block, and because of this, he/she may wrongly
assume that it was a failure. Every nerve block, whether it provides you
with relief or not, will always provide a good Pain Physician with
invaluable information that can be used to ultimately find the missing piece to
the puzzle.