Cervical facet arthropathy is a degenerative process that may lead to axial and mechanical spine pain. Cervical facet mediated pain may occur secondary to arthropathy, trauma, whiplash injury, or secondary to prior surgery. Diagnostic blocks have been demonstrated to be the most reliable way to diagnose facet-mediated pain and no studies for non-interventional treatments for confirmed facet-mediated pain have been evaluated. The majority of conservative treatments for facet-mediated pain have been anecdotal or based on studies for non-specific neck pain. This chapter will discuss important components of the history, physical examination, diagnosis, and treatment of cervical facet-mediated pain.
KeywordsCervical, Facet, Neck, Pain, Whiplash, Zygapophyseal
|M47.812||Spondylosis w/o radiculopathy or myelopathy|
|M54.02||Facet syndrome (cervical)|
|S13.4||Neck: Sprain of atlanto-axial (joints), sprain of atlanto-occipital (joints), whiplash injury|
The cervical facet joints have long been identified as a potential pain generator for neck pain. The facet joints are located in the posterior portion of the cervical spine and the paired synovial joints articulate between adjacent vertebrae ( Fig. 2.1 ). The coronal oblique orientation of the joints allows greater flexion, extension, and lateral bending of the cervical spine. Cervical facet joint arthropathy is mostly degenerative in nature, although facet joint mediated pain can occur secondary to trauma, acceleration-deceleration injury such as whiplash, or following prior fusion surgery due to adjacent segmental changes.
In the case of chronic axial neck pain, the facet joints have been reported to be the primary pain generator in about 25% to 66% of cases. In patients with chronic facet-mediated pain, 58% to 88% of patients complained of associated headaches. Cervical facet joint arthropathy increases with age and in cadaveric studies, the C4-5 level was found to be most frequently affected followed by C3-4, C2-3, C5-6, and C6-7. The findings of facet joint arthropathy have been shown to be independent of race and gender. However, based on the most clinically affected segments diagnosed by diagnostic blocks, the C2-3 and C5-6 joints were shown to be most commonly affected. In patients who complain of posterior headaches following a whiplash injury, the C2-3 joint has been estimated to be the pain generator in 50% to 53% of patients. Following trauma, the C5-6 joint has been shown to be the most commonly affected level.
Patients who present with facet-mediated pain secondary to facet arthropathy typically have progressive pain as opposed to acute pain with the main exception being whiplash injuries. Patients typically have axial neck pain that is unilateral and does not radiate past the shoulder. Weakness, numbness, or any other neurologic symptom are typically not seen in patients with primary facet-mediated pain, but may occur if there is simultaneous nerve root injury. Pain may worsen with cervical extension and axial rotation. Referral pain patterns arising from the cervical facet joints have been described using noxious stimulation of the joints in asymptomatic subjects that was subsequently validated with diagnostic blocks. Referral patterns have been described as seen in Fig. 2.2 .
Examination for cervical facet-mediated pain has been shown to be inconsistent, although paraspinal tenderness has been demonstrated to be most correlative with facet-mediated pain. Aside from palpation, examination usually consists of range of motion testing, segmental analysis, and neurologic examination to rule out neurologic impairment. Point tenderness may be associated with exacerbation of symptoms with cervical extension and axial rotation and loss of cervical motion. Manual examination of the joints may be performed with the patient supine. The C2 spinous process can be palpated as the first protuberance below the occiput while the C7 spinous process is the largest and most palpable and is fixed in comparison to the relatively mobile C6 spinous process. The facet joints may be palpable as hard bony masses about 1.3 to 2.5 cm lateral to the spinous process. Unless cervical disc or nerve root disease is also present, the findings of the neurologic examination are otherwise typically normal.
Patients may have difficulty with cervical extension and rotation, although they may be limited in all planes due to associated muscle spasm. Patients may complain of difficulty driving due to limited ability to turn their head and may also have interference with various activities of daily living and work tasks that may require rotation of the cervical spine.
Aside from the history and physical examination, the gold standard for diagnosis of cervical facet-mediated pain are fluoroscopically guided medial branch blocks. Theoretically, the diagnosis can be confirmed by the alleviation of pain by injecting local anesthetic around the medial branches of the dorsal rami, which supply the nociceptive fibers to the facet joints. However, there is no consensus on what constitutes a positive block as well as whether a single or comparative block should be performed with anesthetics of different durations. False positive rates have been reported to be around 27% to 63% with a single block, thus causing some to advocate for comparative blocks, although this continues to be controversial in the interventional spine community.
Imaging of the facet joints includes plain films, computed tomography (CT), and magnetic resonance imaging (MRI). Disc degeneration has been shown to precede development of facet joint arthropathy. Population-based studies of patients with neck pain who underwent cervical spine imaging failed to show a correlation of neck pain and facet joint arthropathy in men and women between the ages of 20 and 65. Findings on CT and MRI have been unable to predict success with facet joint blocks and radiofrequency denervation, respectively.
Use of bone scintigraphy using single photon emission computed tomography (SPECT) has been studied in predicting a favorable response to facet joint injections in the lumbar spine, although this is not commonly done at this time in the cervical or lumbar spine.