CHAPTER 62 An Algorithmic Methodology for Cervical Axial Neck Pain
HISTORICAL ASPECTS
Fluoroscopically guided cervical injections have been utilized in the clinical management of cervical axial neck pain for several decades. It is only over the past decade and a half that these techniques have been systematically employed for diagnostic and therapeutic purposes. Smith and Nichols1 first described cervical discography in 1957 as a diagnostic tool for the evaluation of cervical intervertebral disc degeneration. A year later, Cloward2 reported the indications for diagnostic cervical discography. In 1964, Holt3 suggested that discography did not have diagnostic value. In contrast, Simmons and Segil4 reported that cervical discography was a reliable diagnostic tool in the determination of a symptomatic cervical disc level in the setting of degenerative disc disease of the cervical spine. Bogduk and Marsland,5 in 1986, identified the value of local anesthetic blockade of the medial branch nerves to the cervical facet joints, implicating CFJS as a cause of cervicogenic headaches. In 1987, Whitecloud and Seago6 demonstrated the validity of cervical discography as a diagnostic tool. A year later, Bogduk and Marsland7 determined that cervical facet joints could cause neck and/or head pain. This study generated pain referral patterns that were constructed from cervical regions from which patients obtained symptom relief after local anesthetic blockade of the cervical facet joints. In 1990, Dwyer et al.8 described pain referral maps of the cervical facet joints in normal volunteers by distending the joint capsule with contrast injected under fluoroscopy. April et al.9 then assessed the accuracy of the pain referral maps. The location of symptomatic cervical facet joints in patients with cervicogenic neck pain were predicted from the pain referral maps and then assessed with confirmatory local anesthetic blockade of the cervical facet joint. In 1993, Barnsley et al. investigated the diagnostic value of comparative local anesthetic blockade of the cervical facet joints.10 They reported that false positives were present with single diagnostic cervical facet joint injections.11 Barnsley et al., in 1994, reported that intra-articular facet joint steroid injections were efficacious in less than 50% of patients for whiplash-induced cervical facet joint pain syndrome leading to chronic neck pain.12 Also in 1994, Dreyfuss et al.13 determined that the atlanto-occipital and atlantoaxial joints may be nociceptive structures. Subsequently, pain referral maps of the atlanto-occipital and atlantoaxial joints were constructed from this study of asymptomatic volunteers.14 In 1995, Lord et al.15 investigated the value of comparative local anesthetic cervical facet joint blocks in the diagnosis of cervical facet joint pain in relation to placebo-controlled cervical facet joint injections. Fluoroscopically guided placebo-controlled local anesthetic injections were utilized by Barnsley et al.16 and Lord et al.17 to investigate the prevalence of whiplash-induced chronic cervicogenic neck pain and headaches. Slipman et al. reported on the outcomes of intra-articular cervical facet joint steroid injections for traumatically induced C2–3 headache.18 In 1995, Saal19 showed favorable outcomes for nonoperative treatment including the use of cervical epidural space steroid injections for painful cervical disc herniations and radiculopathy. Schellhas et al.20 reported that magnetic resonance imaging (MRI) cannot reliably identify the source(s) of cervical discogenic pain and that significant cervical disc annular tears demonstrated by discography often escape MRI detection. Within that study, they also reported upon the distribution of pain referral patterns for the C3–4 to C6–7 disc levels. That same year, Lord et al.17 demonstrated the efficacy of percutaneous radiofrequency neurotomy for patients with neck pain due to CFJS in a double-blinded, placebo-controlled trial. In 1999, McDonald et al.21 described the long-term effectiveness of cervical radiofrequency neurotomy for chronic neck pain and demonstrated that repeat radiofrequency ablation will reinstate the same degree of pain relief if the pain returned after a successful initial procedure. In 2000, Grubb and Kelly22 reported that cervical discograms frequently identified abnormal concordantly painful fissured discs at multiple disc levels in more than 50% of the 173 patients examined, suggesting that treatment decisions based on fewer discs injected during discography should be reconsidered until more disc levels have been assessed. In 2003, Slipman et al.23 reported upon the various cervical discogenic pain referral maps provoked during cervical discography in the first large multicenter prospective study investigating discogenic pain referral patterns and laterality of pain referral.
ALGORITHMIC METHODOLOGY
A working knowledge of the anatomic interrelationships in the cervical spine is important in understanding the pathomechanism of cervical spinal disorders that cause cervical axial neck pain. Similarly, understanding the epidemiology, etiology, and pathophysiology of these disorders is helpful in organizing a differential diagnosis, initiating a logical systematic treatment plan, and ultimately formulating diagnostic and therapeutic treatment algorithms. This chapter will focus on cervical axial neck pain that has been nonresponsive to a reasonable trial of physical therapy, NSAIDs, acute pain medications, activity modifications, time, and relative rest. Musculoskeletal entities such as muscular strains will not be discussed since these entities typically resolve within 2 months of appropriate nonoperative treatments (Table 62.1).24–26
| Axial pain | Limb pain |
|---|---|
| Cervical sprain/strain | Musculoskeletal |
| Disc herniation | Radiculopathy |
| Fibromyalgia | – Disc herniation |
| Myofascial pain syndrome | – Stenosis |
| Whiplash syndrome |
Clinical assessment
Traumatic versus atraumatic
In formulating an accurate differential diagnosis, obtaining a comprehensive history is the initial step. A detailed history is critical because it will provide the clinical basis of any diagnostic and treatment paradigm and as well as offer prognostic implications. For instance, a history of trauma provides the possibility that more than one structure sustained a traumatic injury. It has been well documented that whiplash injuries can injure a cervical facet joint, intervertebral disc, cervical nerve root, or a combination of these structures.16,27–34 A common cervical intervertebral disc injury that occurs as a result of whiplash is a transverse tear near the anterior vertebral rim.29,30 This ‘rim lesion’ is caused by distraction and shearing at the annular–endplate interface by sudden cervical extension.35–37 Rim lesions have been shown to predispose the disc to premature degeneration.30,31,38–40 Other injuries that can occur may include disc contusion or herniation, facet hemarthroses, cervical nerve root shearing, or fractures of the articular processes.16,27–33,36,41–47 Organizing the history as traumatic versus atraumatic is useful when attempting to formulate a differential diagnosis. It is reasonable to assume that traumatically induced cervical axial neck pain may arise from more than one structure. For nontraumatic cases, the law of parsimony is applied and it is assumed that there is only one structure responsible for the painful symptoms.
Segmentation of pain
The next step in formulating a differential diagnosis within the framework of a diagnostic algorithm is segmenting the distribution of pain into quadrants: head, neck, upper back or periscapular, upper arm, and forearm. The relative distribution of pain in these regions assists in determining whether the pain is axial or radicular. Cervical axial pain includes the neck, head, and/or interscapular regions. Radicular pain refers to upper limb symptoms that are greater or more pronounced than axial complaints. Understanding the various pain referral patterns or dynatomes of the cervical nerve roots will assist in properly interpreting the segmented distribution of painful symptoms. For instance, upper back or periscapular pain that is more intense than neck pain in the patient without arm symptoms can be of radicular etiology despite its relative axial location. A more detailed discussion regarding the historical and examination features of cervical radicular pain and how to differentiate that from cervical axial pain is contained in Chapter 57. It is also generally considered that cervical axial neck pain that is greater in intensity than extremity pain is typically caused by cervical facet joint syndrome or cervical internal disc disruption. However, ipsilateral lower cervical neck pain may be caused by injury to the fourth or fifth cervical nerve root.48 In these more challenging clinical scenarios, physical examination findings can provide additional information to further rank order the differential diagnosis. For example, physical examination findings of increased focal suboccipital pain during 45 degrees of cervical flexion and sequential rotation would suggest pain emanating from the C1–2 joint.13,14
Upper versus lower cervical axial neck pain
Formulating a probability analysis within each grouping, axial or radicular, is the next critical step in successfully implementing treatment algorithms to arrive at an accurate diagnosis. For instance, a history of unilateral occipital headaches more intense than neck pain following a traumatic injury is more suggestive of upper cervical facet joint syndrome than cervical internal disc disruption.16,33 Upper cervical neck pain may be due to cervical internal disc disruption or from an upper cervical facet joint (C2–3, C3–4, C1–2).33 In this scenario, a history of trauma, unilateral symptoms, or the presence of occipital headaches tends to favor the presence of cervical facet joint syndrome involving an upper cervical facet joint. Similarly, an atraumatic history, bilateral symptoms, or the absence of occipital headaches, would more likely suggest cervical internal disc disruption syndrome as the cause of upper cervical axial neck pain. Lower cervical neck pain may be caused by a lower cervical facet joint, intervertebral disc, or an injury to the fourth or fifth cervical nerve root.16,27–33 One may suspect cervical facet joint syndrome more than internal disc disruption if there is focal tenderness following palpation of an isolated cervical facet joint or if the patient is able to point to the painful area corresponding to the distribution of pain reported for a particular facet joint.49 However, one cannot make the diagnosis of CFJS just on the presence of focal tenderness of the cervical paraspinal muscles in the region of a cervical facet joint. In traumatic injuries such as whiplash, cervical facet joint syndrome maybe more common than an injury to an upper cervical nerve root;33,50 however, this may be a consequence of the paucity of epidemiologic data for whiplash-induced cervical radicular pain.
