Cervicogenic headache is referred pain from cervical structures innervated by the upper three cervical spinal nerves. Cervicogenic headache can be defined as headache that is provoked by neck movement or pressure over tender points in the neck with associated reduced range of movement of the cervical spine. The headache originates from the neck and spreads over the occipital, temporal, and frontal regions. The clinical presentation is not enough to make a definite diagnosis of cervicogenic headache.
Response to diagnostic block of the nerve supply of these cervical structures or intraarticular injection of local anesthetic into the symptomatic joint is considered the major criterion in the diagnosis of cervicogenic headache.
In this chapter we will review the diagnostic criteria, differential diagnosis, and management of cervicogenic headache.
Keywordsatlanto-axial joint pain, cervicogenic headache, occipital nerve stimulation, occipital neuralgia, occipital neuromodulation, third occipital headache
Cervicogenic headache was initially defined as unilateral headache that is provoked by neck movement or pressure over tender points in the neck with associated reduced range of movement of the cervical spine. The headache occurs in nonclustering episodes and is usually nonthrobbing in nature, originating from the neck and spreading over the occipital, temporal, and frontal regions. However, these clinical criteria are not enough to make a definite diagnosis of cervicogenic headache, as it is sometimes difficult to differentiate clinically between cervicogenic headache, migraine, and tension-type headache.
Response to diagnostic block of the nerve supply of these cervical structures or intraarticular injection of local anesthetic into the culprit joint is now considered the major criterion in the diagnosis of cervicogenic headache. Also, cervicogenic headache can be unilateral or bilateral. These clinical characteristics prompted the development of new diagnostic criteria for the diagnosis of cervicogenic headache by the International Headache Society (IHS). More recently, the International Classification of Headache Disorders, 3rd edition (ICHD-3) was released.
Any headache fulfilling criterion C
Clinical, laboratory and/or imaging evidence of a disorder or lesion within the cervical spine or soft tissues of the neck known to be able to cause headache
Evidence of causation demonstrated by at least two of the following:
Headache has developed in temporal relation to the onset of the cervical disorder or appearance of the lesion
Headache has significantly improved or resolved in parallel with improvement in or resolution of the cervical disorder or lesion
Cervical range of motion is reduced and headache is made significantly worse by provocative maneuvers
Headache is abolished following diagnostic blockade of a cervical structure or its nerve supply
Not better accounted for by another ICHD-3 diagnosis
Cervicogenic headache is referred pain from cervical structures innervated by the upper three cervical spinal nerves. Thus possible sources and differential diagnoses of cervicogenic headache are: atlanto-occipital joint, median and lateral atlanto-axial joints, C2–C3 intervertebral disc, C2–C3 zygapophyseal joint, upper posterior neck and paravertebral muscles, the trapezius and the sternocleidomastoid muscles, spinal and posterior cranial fossa dura matter, cervical spinal nerves and roots, and the vertebral artery.
Neuroanatomy and Neurophysiology
The spinal nucleus of the trigeminal nerve extends caudally to the outer lamina of the dorsal horn of the upper three to four cervical spinal segments. This is known as the trigeminocervical nucleus, which receives afferents from the trigeminal nerve and the upper three cervical spinal nerves. Convergence between these afferents accounts for the cervical-trigeminal pain referral. Therefore, pain originating from cervical structures supplied by the upper cervical spinal nerves could be perceived in areas innervated by the trigeminal nerves such as the orbit and the frontotemporoparietal region. Bartsch and Goadsby showed that noxious stimulation of the greater occipital nerve induces increased central excitability of supratentorial afferents, and vice versa, stimulation of the dura mater increases trigeminocervical neuron’s responsiveness to cervical input.
Common Sources of Cervicogenic Headache
In this chapter, I discuss the clinical presentations of the common causes of cervicogenic headache and how to come up with an accurate diagnosis and a plan of care ( Fig. 22.1 ).
The lateral atlanto-axial joint, which is innervated by the C2 ventral ramus, is not an uncommon cause of cervicogenic headache. It may account for 16% of patients with occipital headache. In human volunteers, distending the lateral atlanto-axial joint with contrast agent produces occipital pain.
Clinical presentations suggestive of pain originating from the lateral atlanto-axial joint include occipital or suboccipital pain, focal tenderness over the suboccipital area or over the transverse process of C1, restricted painful rotation of C1 on C2, and pain provocation by passive rotation of C1. These clinical presentations merely indicate that the lateral atlanto-axial joint could be a possible source of occipital headache; however, they are not specific and therefore cannot be used alone to establish the diagnosis. The only means of establishing a definite diagnosis is a diagnostic block with intraarticular injection of local anesthetic.
The pathology of lateral atlanto-axial joint pain is usually osteoarthritis or posttraumatic in nature. However, the presence of osteoarthritic changes in imaging studies does not mean that the joint is necessary painful; also, the absence of abnormal findings does not preclude the joint from being painful.
There is no conservative treatment for lateral atlanto-axial joint pain. However, intraarticular steroids are effective in short-term relief of pain originating from the lateral atlanto-axial joint. Long-lasting pain relief may require arthrodesis of the lateral atlanto-axial joint.
Atlanto-axial joint intraarticular injection has the potential for serious complications, so it is imperative to be familiar with the anatomy of the joint in relation to the surrounding vascular and neural structures ( Fig. 22.2 ). The vertebral artery lies lateral to the atlanto-axial joint as it courses through the C2 and C1 foramina. Then it curves medially to go through the foramen magnum, crossing the medial posterior aspect of the atlanto-occipital joint (see Fig. 22.2 ). The C2 dorsal root ganglion and nerve root with its surrounding dural sleeve crosses the posterior aspect of the middle of the joint. Therefore during atlanto-axial joint injection, the needle should be directed toward the posterolateral aspect of the joint. This avoids injury to the C2 nerve root medially or the vertebral artery laterally ( Figs. 22.3 to 22.5 ). Meticulous attention should be observed to avoid intravascular injection, as the anatomy may be variable. Injection of a contrast agent should be performed under real time fluoroscopy preferably with digital subtraction prior to injection of the local anesthetic, as negative aspiration is not reliable. Inadvertent puncture of the C2 dural sleeve with cerebrospinal fluid (CSF) leak or high spinal spread of the local anesthetic may occur with atlanto-axial joint injection if the needle is directed only a few millimeters medially. Spinal cord injury and syringomyelia are potential serious complications if the needle is directed further medially.
C2–C3 Zygapophysial Joint and Third Occipital Headache
C2–C3 zygapophyseal joint is innervated by the third occipital nerve, which is the superficial medial branch of the dorsal ramus of C3. Pain stemming from this joint (named third occipital headache) was seen in 27% of patients presenting with cervicogenic headache after whiplash injury. Tenderness over the C2–C3 joint is only suggestive, and controlled diagnostic third occipital nerve block (ONB) is mandatory to confirm the diagnosis.
Earlier reports showed that radiofrequency neurotomy of the third occipital nerve was not effective ; however, with improved radiofrequency technique, complete relief was obtained in 88% of patients with third occipital headache ( Fig. 22.6 ). The C2–C3 zygapophyseal joint intraarticular steroid injection was effective in one study. On the other hand, Barnsley et al. reported a lack of efficacy of intraarticular steroids for chronic pain stemming from the cervical zygapophyseal joints.
Third Occipital Nerve Neurolysis
The third occipital nerve is the superficial medial branch of C3 dorsal ramus. It supplies the C2–C3 zygapophysial joint while crossing the joint laterally. Also, it supplies part of the semispinalis capitis muscle and its cutaneous branch supplies a small area of skin below the occiput.
Third occipital radiofrequency neurolysis was shown to be effective in the treatment of headache stemming from the C2–C3 joint. The most common side effect is incomplete lesioning of the third occipital nerve because of its variable anatomy. Using the three-needle-technique accommodates all variation in the anatomy of the third occipital nerve from just lateral to the joint line to above or below the joint, and creating consecutive lesions no more than one electrode width from adjacent lesion markedly improved the results (see Fig. 22.6 ).
Anesthesia dolorosa has not been reported with this particular block. However, numbness in the cutaneous distribution of the nerve is very common, whereas dysesthesia and hypersensitivity typically at the border of the area of numbness occur in up to 50% of cases; however, these are temporary complications that usually persist only for few days to weeks. Temporary ataxia has been reported in most patients, as third occipital neurotomy partially denervates the semispinalis capitis muscles with the resultant interference of the tonic neck reflexes. Most patients can overcome this sensation by relying on visual cues. Other possible complications that are not specific to third ONB, as they may occur with cervical medial branch blocks at lower levels, include infection, hematoma formation, and injury to the vertebral artery or the cervical nerve root if the needle is not positioned appropriately.
According to the ICHD, occipital neuralgia is coded separately under cranial neuralgias. It is discussed because of its relevance to cervicogenic headaches.
The diagnostic criteria include the following:
Paroxysmal stabbing pain, with or without persistent aching between paroxysms, in the distribution(s) of the greater, lesser, and/or third occipital nerves
Tenderness over the affected nerve
Pain is eased temporarily by local anesthetic block of the nerve
Occipital neuralgia was long thought to be the result of entrapment of the greater occipital nerve as it emerges from the trapezius muscle. However, surgical nerve release gives only short-term relief in about 80% of cases, while nerve excision provides short-term relief in about 70% of patients. Occipital neuralgia must be distinguished from occipital referral of pain from the atlanto-axial or upper zygapophyseal joints or from tender trigger points in neck muscles or their insertions.
The greater occipital nerve is the terminal branch of the dorsal ramus of C2 with contribution from C3, while the lesser occipital nerve is a branch of the dorsal ramus of C3 with contributions from C2. Segmental nerve blocks at C2 and C3 may be necessary to make the diagnosis in some cases.
Cryoneurolysis, radiofrequency ablation, and more permanent neuroablative approaches such as dorsal rhizotomy at C1–C3 and partial posterior rhizotomy at C1–C3 showed variable responses. Recently, there has been a growing interest in pulsed radiofrequency (PRF) for the treatment of intractable occipital neuralgia. To date, there are two prospective studies and one retrospective multicenter study with promising results ( Table 22.1 ). However, the lack of randomized controlled studies and the variation in the technique with landmark versus imaging guidance limit the wide application of this treatment modality.