Basis, indications and risk
It is the destruction of the nerves in the facet joints, normally
by burning them with radiofrequency current.
To improve pain in instances of facet joint degeneration.
There are no nerves in the cartilage of the facet
joint. These are located in the bone placed underneath. This
is why joint degeneration may not cause problems until the bone
is affected. When this occurs, pain nerves are activated, with the
subsequent onset of pain.
Conceptually, rhizotomy aims at destroying the nerves in the facet
joint to eliminate pain sensation. It is usually performed by burning
the joint nerves. Obviously, this procedure is only considered in
those cases in which pain is due to activation of these nerves by
facet joint disorders.
However, each facet joint enfolds nerves from two, and in some
individuals three, different vertebral levels. Thus, for example,
the facet joint between the fourth and fifth lumbar vertebrae may
receive nerves that originate from, for example, the third, fourth
and fifth lumbar level. Therefore, nerve destruction of only one
of these levels may have no effect, or have a temporary effect until
the remaining nerves take on its nerve field.
Also, it was traditionally believed that all pain nerves reached
the medulla through the posterior root, which permitted the localization
of the site where nerves had to be destroyed to eliminate the pain
originated in the facet joint. However, recent studies show that,
although there are individual variations, in some individuals up
to 20% of pain nerves reach the medulla through the anterior root.
Muscle nerves also pass through this root so it cannot be destroyed
since, in doing so, it would cause paralysis of the innervated muscles.
Evidence of efficacy
The existing recommendations
based on scientific evidence do not consider studies on this topic.
Since the publication of those guidelines, some rigorous studies
have been performed on this technique. In summary, these studies
coincide in demonstrating that rhizotomy can be effective in a small
subgroup of chronic patients. The key is to select them very meticulously
with the criteria described in "indications" of this section.
Risks and contraindications
The inherent risks of surgery (infections, hemorrhage, etc.),
although they rarely occur, and pain at the operation site, which
persists during several days.
The existing evidence based recommendations
do not recommend rhizotomy, essentially because they are focused
on the treatment of acute cases and rhizotomy can only be considered
in chronic cases.
It may only be indicated in cases that comply with the following
- Characteristics of pain:
- local pain with no radiated
pain nor signs of nervous compression (such as loss of
strength or reflex or sensibility alterations)
- pain resistant to non-surgical treatments for more than
- Pain origin:
- Rhizotomy should not be performed on patients whose other
organic alterations of the spine may explain the pain.
- - It must be assured that pain results from alterations
of the facet joint. This is the most important criterium to
recommend rhizotomy and also the most difficult one to prove.
The detection of signs of joint degeneration through radiological
test is not enough, since many healthy persons have it.
To verify it, a test with anaesthetics is needed (see below).
- Test with anaesthetics:
- - Before a rhizotomy treatment, an anaesthetic infiltration
test at the joint should be done. If pain is due to the activation
of nerves at the joint, pain should disappear completely.
Some authors recommend doing three infiltrations spaced out
in time; two with anaesthetics and one with a placebo (substance
of similar appearance but with no effect), without letting
the patient know which is which).
- - Rhizotomy should only be performed on those patients in
which pain disappears completely with the anaesthetic injections
and remains unchanged with the placebo shot.
- - An adequate selection of patients is the key criterium
to assure that Rhizotomy has acceptable chances of success.
- - It should only be considered on patients whose pain complies
with the above described characteristics, after discarding
that it may be due to any alteration different from that of
the facet joint and where pain disappeared with the anaesthetic
- - The destruction of the root should be performed under
radiologic control, to assure it is done in the right place.
- - The roots of, at least, two segments should be destroyed
and two or three lesions should be made at each location,
to accomodate personal variations in the course of the nerve.
Available studies suggest Rhizotomy in cases in which each and
all of the requisites described are met and have:
- Pain at the neck from injuries in the facet joint at some level
between the seventh and third cervical vertebra (technically,
it is very difficult to perform Rhizotomy at levels above this
one), and in which the injury is due to a cervical whiplash (abrupt
flexo-extension of the neck) caused by a car accident,
- Lumbar pain.
Even when it is successful, the effect of rhizotomy tends to diminish