Medial Branch Block and Radiofrequency Description
Medial branch blocks are useful diagnostic injections for spinal arthritis. Spinal arthritis
(spondylosis) is noted for the following: Pain is dull, deep and difficult to localize but is
accentuated by pressure over the facet joints. Pain may have an “aching” quality and
often is primarily on each side of the spine, worse with twisting, change in weather, and
leaning backwards. Facet arthropathy may be seen on Xray, MRI, or CT scan. In the
lumbar spine, pain may be referred into the buttocks, hips and thighs, but pain below the
knee or into the foot is rare. Mid back facet pain appears to be uncommon and the
diagnosis should be considered only after all other etiologies have been ruled out.
Clinical data suggests less success in relieving pain from thoracic facets than either the
neck or low back. Cervical facet pain is primarily felt in the neck, but can radiate into
the head and into the shoulders and upper back. Cervical facet pain is often implicated in
tension headache that starts in the neck and radiates over the head and describes as
tugging behind the eyes.
Medial branch blocks are preferred over injecting into the facet joints based on a review
of the medical literature. ISIS guidelines (International Spinal Intervention Society) and
all insurance carriers require at least 50% relief using a few drops of local anesthetic.
The procedure is repeated using a different anesthetic agent on a different day to prove
that the facet is the pain generator. Blockade may be combined with steroids to produce
longer-lasting relief. This is not backed up by the literature, but is common in practice.
If both diagnostic test injections provide significant but short term relief, RF neurotomy
is performed. Radio-frequency of the medial branches (burning the nerves), above and at
the level of the painful facet joint has demonstrated relief for about 14 months in the
lower back and 10 months in the neck. Our clinic results are slightly better than the
average.
In summary, the medial branch blocks (facet injections) are not performed in a
series, but are repeated when the pain returns and can lead to burning the nerves
for near permanent relief. If an injection fails to provide more than 50% relief
during the local anesthetic phase, the pain is not coming from that joint.