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Many of us wonder about the efficacy and cost
effectiveness of widespread spinal steroid injections. In order to
obtain up to date information, I recently interviewed a physician who
performs these frequently. Dr. Robert H. Dorwart, a respected
neuroradiologist, is Medical Director for the Center for Diagnostic
Imaging. Dr. Dorwart is a member of the American Society of Spine
Radiology, the International Spine Injection Society, the American
Society of Neuroradiology, the American College of Radiology and many
more respected professional organizations. He is a recognized leader in
MRI and CT interpretations as well as, in diagnostic and therapeutic
procedures. Some of the most highly respected spine surgeons in
Indianapolis, IN, where Dr. Dorwart practices, utilize his expertise by
referring patients for spinal injection procedures.
Dr. Dorwart stated that most of the steroid
injection procedures he performs are ordered relative to the following
diagnoses: A herniated disc with or without nerve root compression,
spinal stenosis, chronic disc degeneration, and a bulging disc with
nerve compression. Almost all have been classified as having chronic
spinal caused pain, with imaging studies sometimes done elsewhere,
confirming the diagnosis. Chronic pain is defined as having lasting for
over 4-6 weeks, and with the patient having failed other conservative
treatment such as NSAIDS, oral steroids, and physical therapy.
Because the goal is to deliver the steroid as
perfectly as possible to the area of inflammation and, given the
normally occurring anatomic variations in patients, CT imaging is
essential, in Dr. Dorwart’s opinion. Proper placement is correlated
with the imaging studies available and with input from the referring
physician. He stated the steroid only remains at the injection site for
24-48 hours and then success is dependent on the effectiveness of the
residual anti-inflammatory effect .
Of the following – nerve root injections, facet
injections, and epidural steroids – only the latter should even be
considered without concurrent imaging. And, Dr. Dorwart recommends
ESI’s be done with imaging for more accuracy. To support why, Dr.
Dorwart quoted a study done involving only expert, experienced
anesthesiologists who were asked to perform ESI’s. They were asked to
state when they were in the epidural space and then imaging was used for
confirmation. 20% of the time, the doctor was not in the epidural
space. While no terrible harm is perhaps done, injecting the numbing
agent mixed with the steroid, Marcaine or Lidocaine, into a vein (the
most likely error made in the study) can result in no benefit and, make
the patient queasy. Inserting steroids into the thecal sac can even
cause arachnoiditis.
If there is no good anesthetic (numbing) response
after an injection procedure, it is not a good prognosticator of
benefit. This could occur as a result of:
-Scarring from prior surgeries.
-A disc herniation that is so large it makes absorption impossible due
to blockage.
-The pain is discogenic thus, due to the tears inside the disc, which
cause chemical changes and the injection has no potential for successful
pain relief.
Dr. Dorwart says the “Rule of Three” is accepted
best practice but he does not know the specific origin or how it
evolved. His personal criteria is the expectation that a patient will
get at least 25 % pain reduction before undertaking further injections.
He suggests a minimum interval of at least two weeks. Further, Dr.
Dorwart feels the optimum success from these spinal injection procedures
relies on excellent placement of the steroid, patient education (many
times he is the first to provide an anatomic model or, show and explain
to the patient their imaging films), and that outcome is also impacted
significantly by the patient’s motivation, an issue sometimes in the
Worker's Compensation population.
In summary, Dr. Dorwart said imaging confirms the
doctor is in a safe anatomic location and as close to the pathology as
possible. Currently, a universal formal treatment protocol for spinal
injections is lacking, thus imaging is not mandatory. In Dr. Dorwart’s
“perfect world” he wonders if diagnostic studies done earlier to assure
an accurate diagnosis, more proactive treatment involving pain relief
(via injection), physical therapy and NSAIDS, might not decrease pain,
time off work, result in fewer injections and avoidance of surgery
except where clearly indicated.
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