Cervical spine pain related to the facet joints

Abstract

Neck pain is a common diagnostic entity, with a lifetime prevalence of between 65% and 80%. Appreciation of the role of the cervical facet joints in the etiology of cervical spine pain is paramount to providing sustained pain relief for individuals suffering from degenerative and posttraumatic neck pain. Studies have demonstrated that approximately 60% of patients who sustain whiplash-type rear-end motor vehicle collisions would have pain that results from the facet joints alone, or in conjunction with the cervical intervertebral disks. An appreciation of the anatomical foundation for the development of these painful conditions includes knowledge of the dual, overlapping innervation of each cervical facet joint with contributions from levels at, and above the joint. Medial branch nerves invest the joints; are held closely adherent to the articular pillars by tendons of the semispinalis capitis muscles; and can be treated using local anesthetic nerve blocks followed by radiofrequency (RF) procedures for prolonged benefit. Nerves in facet joints contain modified nociceptors, including silent nociceptors, low-threshold mechanoreceptors, and mechanically sensitive nociceptors. Nerves within facet joints are both free and encapsulated and contain Substance P and calcitonin gene–related peptide. Treatment approaches must address these diverse anatomical and physiological phenomena to provide the highest level of interventional therapy. Large, well-conducted studies have demonstrated the efficacy and safety of providing short-term symptomatic pain relief using cervical facet medial branch nerve blocks. Continuous-energy thermal lesioning RF ablation techniques of the cervical medial branches may produce pain relief that persists for up to 12 months in two-thirds of patients so treated. A systematic review of well-conducted studies recently published confirmed that the evidence in favor of using RF ablation is level II for the long-term effectiveness of RF neurotomy and facet joint nerve blocks in managing cervical facet joint pain. Imaging for performing these procedures is mandatory to assure success and to minimize adverse events from occurring. Fluoroscopy is a standard imaging technique, but ultrasound and even computed tomography scan guidance have been documented to be satisfactory in properly trained interventionalists. The cervical facet joints with their medial branches represent a reliable target for directing interventional therapies aimed at addressing nociceptive type pain, albeit with a neurogenic component. Future studies would reflect our evolving appreciation of these intricate anatomical networks of innervation and their role in the etiology of chronic headache and neck pain.