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Once diagnosed, occipital neuralgia's symptoms can be treated/managed in several ways. Some less invasive treatments are as follows: acupuncture,chiropractic manipulation, occupational therapy, osteopathic manipulation,naprapathic treament, massage, yoga, physical therapy, rest, heat, anti- inflammatory medication, antidepressant medication, anti- convulsant medication, opioid and nonopioid analgesia, and migraine prophylaxis medication. Alternatives to these may include local nerve block, peripheral nerve stimulation, steroids, rhizotomy, phenol injections, antidepressants, and Occipital Cryoneurolysis.
Other less common forms of surgical neurolysis or microdecompression are also used to treat the condition when conservative measures fail.
Occipital neuralgia is a form of headache that involves the posterior occiput in the greater or lesser occipital nerve distribution. Pain can be severe and debilitating, with frequent paroxysms. Occipital neuralgia can be difficult to distinguish from other types of headache and, therefore, diagnosis can be challenging. Local anesthetic block of the occipital nerves, either peripherally or more proximally at the C2 and/or C3 nerve root, may aid in diagnosis. Treatment may include medications, minimally invasive percutaneous procedures, and surgical interventions. This issue of Pain Management Rounds presents the characteristics of occipital neuralgia and outlines available treatment options.
BACKGROUND
Headache accounts for nearly 20 million outpatient visits per year in the United States and
is one of the most common complaints brought to doctors. Nearly 95% of the population will
experience a headache at some point in their life. While the parenchyma of the brain is insensate,
the scalp, head muscles, periosteum, dura, and blood vessels are all pain-sensitive; thus,
there are many possible causes of head and face pain. Occipital neuralgia is a headache
syndrome that may be either primary or secondary.
Primary headaches have no clear structural or disease-related cause, (eg, migraine, tension,
and cluster headaches). Primary headaches constitute the etiology of >90% of head and facial
pain1 and occipital neuralgia is often confused with other primary headache syndromes, including
migraine and cluster headaches.
Secondary headaches have an underlying disease process that may include tumor, trauma,
infection, systemic disease, or hemorrhage.
ETIOLOGY
Patients with occipital neuralgia may be divided into those with structural causes and those
with idiopathic causes. Structural causes include:
• trauma to the greater and/or lesser occipital nerves
• compression of the greater and/or lesser occipital nerves or C2 and/or C3 nerve roots by
degenerative cervical spine changes
• cervical disc disease
• tumors affecting the C2 and C3 nerve roots.
The greater occipital nerve receives sensory fibers from the C2 nerve root and the lesser
occipital nerve receives fibers from the C2 and C3 nerve roots. The third occipital nerve (least
occipital nerve) stems from the medial sensory branch of the posterior division of the C3 nerve root and travels along the greater occipital nerve. It passes
through the trapezius and splenius capitus slightly medial
to the greater occipital nerve. Clinically, the third occipital
nerve may also be involved in causing occipital neuralgia.
Cervical spine changes include spondylosis, arthritis
of the upper cervical facet joints, and thickening of the
ligaments in that area (particularly C1-4 levels).2 Some
cases of presumed occipital neuralgia may in fact be C2 or
C3 radiculopathies. Compression of the greater occipital
nerve is possible as it travels up the neck, passing through
the semispinalis and trapezius muscles. Whiplash or
hyperextension injury may lead to this scenario.3 Other
possible causes include localized infections or inflammation,
gout, diabetes, and blood vessel inflammation.4
Although it cannot be quantified, most patients fall in the
category of “unknown cause,” when no identifiable lesion
is found.
CLINICAL FEATURES
Occipital neuralgia symptoms include aching,
burning, and throbbing pain that is often unilateral and
continuous with intermittent, shocking, shooting pain.
The pain usually originates in the suboccipital area and
radiates to the posterior and/or lateral scalp. Occasionally,
patients report pain behind the eye on the affected side.
Pain may also be perceived over the neck, temple, and
frontal regions.5 Pressure over the occipital nerves may
amplify the pain, but there is usually no clear trigger.
Furthermore, some patients may have a positive Tinel’s
sign over the occipital nerve. Occasionally, neck movements
(eg, extension and rotation) may trigger pain. At
times, patients with occipital neuralgia may experience
symptoms similar to migraine or even autonomic changes
characteristic of cluster headaches. Associated symptoms
include posterior scalp paresthesias, photophobia, and
dizziness. Many patients with occipital neuralgia report a
cycle of pain-spasm-pain.6
DIAGNOSIS
Thorough history-taking and a complete physical and
neurological examination are necessary in diagnosing
headache.7 A diagnosis is usually made based on the
characteristic area of the pain. In addition, finding tender
areas that exacerbate the pain aids in diagnosis. It is
important to clarify whether the cause of occipital neuralgia
is structural or idiopathic. Abnormal findings on neurologic
exam usually indicate a structural cause, in which
case, computed tomography (CT) or magnetic resonance
imaging (MRI) of the head and cervical spine may be
indicated. The work-up of occipital neuralgia should
include assessment for atlanto-axial joint instability.
Patients with a history of rheumatoid arthritis or trauma
should receive a thorough spine work-up. Diagnostic
occipital nerve blockade also aids in diagnosis.
Occipital neuralgia often is confused with migraines
and other headache syndromes (Table 1). In some cases,
occipital neuralgia is misdiagnosed as fibrocytis or
fibromyalgia, cervical spine arthritis, or cervical disc
disease.
TREATMENT OPTIONS
If the cause is structural, then surgical treatment may
be indicated. Because the majority of patients have no
clear structural cause, their treatment is usually symptomatic.
Local nerve blocks, medications, occipital nerve
stimulator implantation, surgical decompression, or
lesioning of the C2 and/or C3 nerve roots, or even the
greater and/or lesser occipital nerves, may be considered.
Occipital neuralgia is often difficult to manage because it
can easily be mistaken for other headache syndromes.8
Management of occipital neuralgia follows the usual
course, starting with the recommended conservative treatment,
conventional therapy, and medications such as
non-steroidal anti-inflammatory drugs (NSAIDs), neuropathic
medications (seizure medications, tricyclic antidepressants),
and possibly opioids.
Conservative treatment
Physical therapy, massage, acupuncture, and heat are
other treatments that can be used for the treatment of
occipital neuralgia.9,10
Medications
Medications that may help relieve pain in occipital
neuralgia include gabapentin 300-3600 mg/day, carbamazepine
400-1200 mg/day, phenytoin 300-600 mg/day,
valproic acid 500-2000 mg/day, and baclofen 40-120
mg/day. NSAIDs and opioids may also be beneficial.
NERVE BLOCKS
Nerve blocks consisting of steroids and local anesthetics may also be considered for treatment of occipital neuralgia.11
Occipital nerve block
Occipital nerve block is indicated for the diagnosis or treatment of occipital neuralgia. The greater occipital nerve is 2.5 to 3 cm lateral to the external occipital protuberance and medial to the occipital artery. The third occipital nerve is medial to the greater occipital nerve
and the lesser occipital nerve is about 2.5 cm lateral to the artery.
The greater and third occipital nerves are blocked slightly above the superior nuchal line, just medial to the occipital artery, which is easily palpated. After antiseptic preparation, a 25 gauge 11 /2 inch needle attached to a 5 ml syringe is placed just medial to the artery at the above location. For diagnostic indications, 1 ml of local anesthetic is injected. For treatment, 3-5 ml of local anesthetic combined with steroid is injected. Anesthesia in the region of the greater occipital nerve usually occurs within 10 to 20 minutes. The most serious complication is piercing the occipital artery and bleeding. Compression of the occipital artery is usually effective in avoiding any significant problems.
C2 and/or C3 ganglion block
C2 and/or C3 ganglion block has proven successful in treating some patients. One case report demonstrated that a patient with severe intractable occipital neuralgia became pain-free for >2 months when given a C2 ganglion block.12 However, repeat blocks with steroids may have adverse effects. A case report published in 2001 demonstrated that a 39-year-old female who had 6 bilateral greater occipital nerve blocks over a period of 3 months developed signs of Cushing’s syndrome. Signs and symptoms were intermittent hypertension, severe muscle weakness, and fluid retention.13
BOTULINUM TOXIN
Botulinum Toxin Type A (botox) is an accepted treatment for migraine headache and muscle spasm related pain with relief up to 4 months.14 Botox was originally used to treat strabismus and cervical dystonia. 15 One trial demonstrated that botox helped chronic daily headache and appeared to have a
cumulative effect with subsequent injections.16
Treatment with botox is generally well-tolerated; side
effects are minimal and include minor discomfort or
bleeding at the time of injection.17 Clinical trials have
shown that botox injections for migraine headaches
reduced the duration, length, and severity of the
headaches, as well as the intake of migraine medications.
18 Botox has been shown to be effective in the
treatment of whiplash-associated disorders that often
cause occipital neuralgia. It improved the pain and
increased the range of motion in these patients.
Because of its success in the treatment of muscle
spasms and migraines, botulinum toxin may prove to
be a reasonable treatment option for occipital neuralgia
in the future.
SURGICAL OPTIONS
Occipital neuralgia can occasionally be treated
successfully with microvascular nerve decompression.
Surgical procedures such as epifacial electric stimulation,
dorsal cervical rhizotomy, neurolysis of the
greater occipital nerve, and radiofrequency rhizotomy
may also be considered. Selective C2 and/or
C3 dorsal rhizotomy is another option, although few
papers have been published assessing its utility.
Dubuisson followed 14 patients over a period of 33
months after partial posterior rhizotomy at C1-3. He
found that 10 of 14 patients (71%) had continuing
significant relief over that period of time.19 CT or
fluoroscopy-guided percutaneous C2 and/or C3
nerve block is also useful for confirmation of occipital
neuralgia and as a preoperative guide for dorsal
cervical rhizotomy.20
RADIOFREQUENCY THERMOCOAGULATION
Radiofrequency thermocoagulation (RF) is
another widely used method to treat occipital
neuralgia. It has many advantages, including safety,
efficacy, a rapid recovery period, and no permanent
scarring. C2 ganglionotomy by RF lesion generator
has also been performed and resulted in cases of
significant pain relief. Pulsed radiofrequency (PRF)
is yet another technique used to treat occipital
neuralgia. In a case report, a patient was treated
with PRF and, after a 12-month follow-up, was
pain-free.21 Recently, a new surgical treatment was
reported consisting of neurolysis of the greater
occipital nerve and sectioning of the inferior oblique
muscle.22
OCCIPITAL NERVE STIMULATOR IMPLANTATION
Surgical implantation of a subcutaneous electrode
along the C1-C3 nerve level has been shown to
significantly reduce the pain of occipital neuralgia in
patients who have failed conservative therapies.23
In one study of 19 patients, 95% reported improvement
in their quality of life and would undergo the
procedure again.24 In another study of 13 patients,
12 reported good-to-excellent pain control at up to
6 years of follow-up.25 The benefit of this procedure
is that it is minimally invasive and there is no permanent
destruction of nerves or other vital structures.
Another advantage is that patients can first undergo a
percutaneous trial of temporary lead placement for
several days prior to permanent lead implantation.
Depending on the results of the temporary percutaneous
trial, patients may or may not undergo the
more invasive permanent lead implantation. It has
been postulated that a successful temporary percutaneous
lead trial, in combination with a successful
diagnostic occipital nerve block, may predict a highly
effective permanent occipital nerve stimulator
implantation.
CONCLUSION
Occipital neuralgia is a headache syndrome that requires careful attention to enable proper diagnosis and treatment. Typically, there is no clear structural cause, although appropriate work-up should be considered in order to rule-out pathologic structural causes. The occipital nerve block is a valuable, simple, and safe diagnostic and therapeutic tool that should be considered early in the course of treatment. If the pain persists despite preliminary therapies, including occipital nerve blockade with local anesthetic and steroid, then botulinum toxin or permanent implantation of a percutaneous occipital nerve stimulator should be considered before destructive C2 and/or C3 root surgical procedures are implemented.
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