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Preemptive Analgesia Before Surgery
By Scott Reuben, MD
Q. How does preemptive analgesia before dental surgery
benefit people who have a risk of CRPS?
There are two types of CRPS patients presenting for surgery.
First, there are those patients with CRPS following dental
extractions and/or surgeries who are coming back for repeat
dental surgery. We have seen neuropathic mediated pain including
mandibular neuralgia and CRPS following dental extractions.
Second, there are those patients with CRPS in other parts
of the body not related to the surgical site (dental). These
patients are still at risk for the spread of CRPS! I would
definitely do a preemptive block on these patients. From my
experience, you would need to perform a sympathetic block
and not just necessarily local anesthetic block. This means
you would need to do a stellate ganglion block on these patients
since this blocks all sympathetic input from the dental/facial
area.
Q. What about preparation for other kinds of surgery?
We have found that at patients who didn't have a history of
CRPS greatly reduced the risk of developing it if they
had regional anesthetics preemptively. A lot of orthopedic
surgeries are at risk for developing CRPS.
We studied patients who were undergoing Dupuytren's surgery-the
incidence of CRPS on surgery for Dupuytren's is as high
as 40%. We compared patients who had a brachial plexus block
to those undergoing general anesthesia. The axiliary block
showed a significant reduction in development of CRPS
post operatively.
Q. What kind of data is there for these procedures?
We have done retrospective and prospective and studies on
people who have a history of CRPS who are scheduled for
surgery on an extremity.
One retrospective study evaluated100 patients with a history
of CRPS who had been treated in pain clinics, their symptoms
had resolved, and they were presenting for surgery,. Of these,
50 patients got a stellate ganglia block and 50 received nothing,
just standard treatment. The 50 patients who had received
the block had a significant decrease in the incidence of flare
up of CRPS; that was very impressive. However, approximately
70 percent of the patients who didn't get the block had a
flare up of CRPS.
So then we did a prospective study looking at the use of IV
regional bier blocks for patients with a history of CRPS undergoing
surgery. The bier blocks by themselves were not particularly
beneficial, but when we added clonidine, again we had a dramatic
reduction in the flare up. Among other things, Clonidine was
blocking the adrenergic response during surgery.
In a review article published in Anesthesiology, we saw approximately
up to 40% of patients develop CRPS following arthroscopies
and knee replacement surgery, surgery for wrist fractures
and carpal tunnel surgery. If you look at the overall numbers
of those orthopedic surgeries being performed, you come out
to an incidence of almost a quarter of a million people developing
CRPS. That's pretty impressive.
Scott S. Reuben MD, Director, Acute Pain Service, Baystte
Medical Center, Professor of Anesthesiology and Pain Medicine,
Tufts University School of Medicine. scott.reuben@aol.com |
