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ANESTHESIA
DOLOROSA
Conditions: Facial Neuralgias
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Description | Possible
Causes | Symptoms | Diagnosis
| Treatments | References
Description
Anesthesia Dolorosa is one of the most dreaded complications of
neurosurgery and is considered to be non-reversible. It occurs
when the trigeminal nerve is damaged by surgery or physical trauma in
such a way that the feeling sensation in part of the face is reduced or
eliminated entirely while the sense of pain remains. According to
Dr. Steven Graff-Radford, director of the Head and Neck Section of
Cedars Sinai Medical Center's Pain Center in Los Angeles, there are two
forms of anesthesia dolorosa, each of which responds best to different
treatments.
Causes
As far as can be seen from the medical literature, anesthesia
dolorosa is caused by injury to the trigeminal nerve or as a
complication of surgery to correct a condition such as trigeminal
neuralgia It can occur after glycerol injection, alcohol
injection, partial nerve sections, radiofrequency rhizotomy, gamma
knife surgery, balloon compressions and microvascular
decompression.
Symptoms
The two main symptoms of AD are facial numbness (much like the
numbness from a dental anesthetic injection) and constant pain.
The pain is usually burning, pulling or stabbing but can also include a
sharp, stinging, shooting or electrical component. Pressure and
"heaviness" can also be part of the pain symptoms. Often there
is eye pain. Cold increases the feeling of numbness sometimes
making the face feel frozen.
Diagnosis
In the past, diagnosis of anesthesia dolorosa was based on
symptoms. More recently, thermograms ( a test that measures minute
temperature differences in the painful area) and nerve blocks of the
sympathetic nervous system are sometimes used to distinguish between two
forms of anesthesia dolorosa.
Treatments
Unfortunately, there are no easy answers to the pain and
discomfort of anesthesia dolorosa. No single treatment
has been found yet that resolves all of the pain. However
there are a number of treatment options that can help to manage the pain
and discomfort.
Drug
Treatments
Capsaicin (topical
applications)
Clonidine
(topical applications)
EMLA
(an anesthetic which hospitals use to numb the skin before inserting
an IV)
Nerve blocks
Nortriptyline
(Pamelor)
Paroxetine
( Paxil).
Carbamazepine
(tegretol) - Used if there is an electrical, shooting pain component
Gabapentin
(Neurontin) - Used if there is an electrical, shooting pain component
Clonazepam
(Klonopin)
Lidocaine (IV treatment)
Ketamine (IV treatment)
Opioids
Other pain
relief strategies that can help include:
Hot and cold
compresses
Acupuncture
Biofeedback
TENS Units
Surgical
Treatments
Once anesthesia dolorosa is diagnosed, any further surgery on the
trigeminal nerve should be avoided as there is little evidence surgery
will improve this condition. In fact, surgery can actually make
anesthesia dolorosa worse.
There are several
forms of brain surgery used to treat anesthesia dolorosa that
selectively destroy parts of the pain-transmission area of the
brain. These are extreme procedures and should only be considered
as a last resort.
Thalamotomy
Cingulotomy
DREZ - Dorsal Root entry Zone
This procedure developed by Dr. Blain Nashold at Duke University in
Georgia includes selectively damaging part of the pain-transmission
system at the back to the head with a radiofrequency electrode.
Most medical professionals advise that this procedure should only be
used as the "absolute last ditch effort" as the success rate
is so low (reported by some at 50%). Complication rates
are as high as 30% and include numbness or loss of coordination
in the arms and hands.
References
Epstein JB, et al.
"Topical clonidine for orofacial pain: a pilot study. " J
Orofac Pain. 1997 Fall;11(4):346-52.
Weigel, George,
Trials
and Treatments of Anesthesia Dolorosa, TN Alert, Winter 1996/1997
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