Neck pain

Background

Neck pain is common in the general population and even more common in a chronic pain management practice.

Very few reliable epidemiologic studies regarding the prevalence of neck pain exist; however, a Finnish study [1] and a Norwegian study [2] estimated the prevalence of neck pain in the general population to be approximately 34%. Furthermore, the prevalence of chronic neck pain, defined as lasting 6 months or longer, is estimated at approximately 14%. [1, 2]

In 1933, Ghormley coined the term facet syndrome to describe a constellation of symptoms associated with degenerative changes of the lumbar spine. [3] Relatively recently, the term cervical facet syndrome has appeared in the literature and implies axial pain presumably secondary to involvement of the posterior elements of the cervical spine.

Cervical facet syndrome. Cervical facet syndrome.
View Media Gallery

Many pain generators are located in the cervical spine, including the intervertebral discs, facet joints, ligaments, muscles, and nerve roots. The facet joints have been found to be a possible source of neck pain, and the diagnosis of cervical facet syndrome is often one of exclusion or not considered at all.

 

Clinical features that are often, but not always, associated with cervical facet pain include tenderness to palpation over the facet joints or paraspinal muscles, pain with cervical extension or rotation, and absent neurologic abnormalities. [4]Imaging studies usually are not helpful, with the exception of ruling out other sources of pain, such as fractures or tumors. Signs of cervical spondylosis, narrowing of the intervertebral foramina, osteophytes, and other degenerative changes are equally prevalent in people with and without neck pain. [5]

Aprill and Bogduk estimated the prevalence of cervical facet joint pain by reviewing the records of patients who had presented with neck pain for at least 6 months secondary to some type of injury. [6] These patients underwent discography, facet joint nerve blocks, or both at the request of the referring physicians.

 

A total of 318 patients were investigated, and 26% of the patients had at least one symptomatic facet joint. However, only 126 patients of the original study group had their facet joints investigated, and 65% of these patients had painful facet joints. [6] Furthermore, 62% of the patients who underwent both discography and facet joint nerve blocks had painful facet joints. This study indicated that the prevalence of cervical facet joint pain may be as low as 26% or as high as 65%, depending on how aggressively it is sought. [6]

 

A large study by Manchikanti et al involved 500 patients with chronic, nonspecific spine pain. The prevalence of facet joint pain was determined using controlled comparative local anesthetic blocks with 1% lidocaine followed by 0.25% bupivacaine. [7] This study indicated that the prevalence of cervical facet joint pain was 55%.

 

It seems apparent that the cervical facet joints may be a common source of neck pain; however, there are other pain generators in the cervical spine, such as the intervertebral discs, that may be involved as well. To evaluate the contribution of the disc to neck pain, a sample of 56 patients were selected from the previous study population. This group consisted of patients who had undergone both discography and facet joint nerve blocks at the same segment of the cervical spine as part of the diagnostic process. [8]

 

The results demonstrated that 41% of this group had a painful disc and facet joint at the same segment, and an additional 23% had a painful facet joint but not a painful disc at the same segment. [8] Therefore, most of the sample had a painful facet joint, but there was often a painful disc at the same level. This finding is not surprising when one considers how the facet joints and discs are intimately involved in motion of the cervical spine.

 

Cervical facet joint pain is a common sequela of whiplash injury. Barnsley and Lord et al studied the prevalence of chronic cervical facet joint pain after whiplash injury using double-blind, controlled, diagnostic blocks of the facet joints. [9] The joints were blocked randomly with either a short-acting or long-acting anesthetic, and, if complete pain relief was obtained, the joint was blocked with the other agent 2 weeks later. Of the 38 patients who completed the trial, 27 obtained complete relief from both anesthetics and longer relief from the longer acting agent. [9] Therefore, the prevalence of this sample is 54%, making cervical facet joint pain the most common cause of chronic neck pain after whiplash injury in this population.

 

Lord and Barnsley et al subsequently studied the prevalence of chronic cervical facet joint pain after whiplash injury using a double-blind, placebo-controlled protocol. [10] The sample consisted of 68 consecutive patients referred for neck pain secondary to a motor vehicle accident and longer than 3 months in duration. Those individuals with a predominant headache underwent a third occipital nerve block and were removed from the study if they received pain relief. [10] The third occipital nerve has a cutaneous branch and a branch to the C2-C3 facet joint; therefore, patients with pain from this segment could not participate in the placebo study because they would feel the effects of the local anesthetic. The remaining 41 patients underwent diagnostic blocks with either a short-acting or a long-acting local anesthetic, followed by a second block with either normal saline or the other anesthetic, followed by a third block with the remaining agent.

 

The investigators reported the positive responders experienced complete relief with each anesthetic and no relief with the normal saline. The prevalence of cervical facet joint pain after whiplash injury was found to be 60%, and the most common levels were C2-C3 and C5-C6.

 

Neck pain is increased in patients with primary headache, according to one study. The authors assessed the prevalence of neck pain in patients with migraine (M), tension-type headache (TTH), or both migraine and TTH (M+TTH) and found that prevalence is highest in coexistent M+TTH, followed by pure TTH and migraine. In comparison with those without headaches, the prevalence of neck pain was significantly higher in those with M+TTH (89.3%), pure TTH (88.4%), and pure migraine (76.2%). In patients without primary headache, the prevalence of neck pain was 56.7%. [11]

 

International

 

To estimate the global burden of neck pain, a systematic review was performed on the prevalence, incidence, remission, duration, and mortality risk of neck pain. The global point prevalence of neck pain was 4.9%. Disability-adjusted life years increased from 23.9 million in 1990 to 33.6 million in 2010. Out of all 291 conditions studied in the Global Burden of Disease 2010 Study, neck pain ranked 4th highest in terms of disability as measured by years lived with disability (YLDs) and 21st in terms of overall burden. [12]

Functional Anatomy

The cervical spine is made up of the first 7 vertebrae and functions to provide mobility and stability to the head, while connecting it to the relative immobile thoracic spine (see the image below). The first 2 vertebral bodies are quite different from the rest of the cervical spine. The atlas, or C1, articulates superiorly with the occiput and inferiorly with the axis, or C2.

 
Cervical vertebra. Cervical vertebra.
View Media Gallery
 

The atlas is ring-shaped and does not have a body, unlike the rest of the vertebrae. The body has become part of C2, and it is called the odontoid process, or dens. The atlas is made up of an anterior arch, a posterior arch, 2 lateral masses, and 2 transverse processes. The transverse foramen, through which the vertebral artery passes, is enclosed by the transverse process. On each lateral mass is a superior and inferior facet (zygapophyseal) joint. The superior articular facets are kidney-shaped, concave, and face upward and inward. These superior facets articulate with the occipital condyles, which face downward and outward. The relatively flat inferior articular facets face downward and inward to articulate with the superior facets of the axis.

 

The axis has a large vertebral body, which contains the fused remnant of the C1 body, the dens. The dens articulates with the anterior arch of the atlas via its anterior articular facet and is held in place by the transverse ligament. The axis is composed of a vertebral body, heavy pedicles, laminae, and transverse processes, which serve as attachment points for muscles. The axis articulates with the atlas by its superior articular facets, which are convex and face upward and outward.

 

The remaining cervical vertebrae, C3-C7, are similar to each other, but they are very different from C1 and C2. They each have a vertebral body, which is concave on its superior surface and convex on its inferior surface. On the superior surfaces of the bodies are raised processes or hooks called uncinate processes, which articulate with depressed areas on the inferior aspect of the superior vertebral bodies called the echancrure or anvil. These uncovertebral joints are most noticeable near the pedicles and are usually referred to as the joints of Luschka.[13] These joints are believed to be the result of degenerative changes in the annulus, which leads to fissuring in the annulus and the creation of the joint. [14]The spinous processes of C3-C5 are usually bifid, in comparison to the spinous processes of C6 and C7, which are usually tapered.

 

The facet joints in the cervical spine are diarthrodial synovial joints with fibrous capsules. The joint capsules in the lower cervical spine are more lax compared with other areas of the spine to allow for gliding movements of the facets. The joints are inclined at 45° from the horizontal plane and angled 85° from the sagittal plane. This alignment helps to prevent excessive anterior translation and is important in weight bearing. [15]

 

The fibrous capsules are innervated by mechanoreceptors (types I, II, and III), and free nerve endings have been found in the subsynovial loose areolar and dense capsular tissues. [16] In fact, there are more mechanoreceptors in the cervical spine than in the lumbar spine. [17] This neural input from the facets may be important for proprioception and pain sensation and may modulate protective muscular reflexes that are important in preventing joint instability and degeneration.

 

The facet joints in the cervical spine are innervated by both the anterior and dorsal rami. The occipitoatlantal (OA) joint and atlantoaxial (AA) joint are innervated by the ventral rami of the first and second cervical spinal nerves. Two branches of the dorsal ramus of the third cervical spinal nerve innervate the C2-C3 facet joint, a communicating branch and a medial branch known as the third occipital nerve.

 

The remaining cervical facets, C3-C4 to C7-T1, are supplied by the dorsal rami medial branches that arise one level cephalad and caudad to the joint. [18, 19]Therefore, each joint from C3-C4 to C7-T1 is innervated by the medial branches above and below. These medial branches send off articular branches to the facet joints as they wrap around the waists of the articular pillars.

 

Intervertebral discs are located between each vertebral body caudad to the axis. The discs are composed of 4 parts, including the nucleus pulposus in the middle, the annulus fibrosis surrounding the nucleus, and 2 end plates that are attached to the adjacent vertebral bodies. The discs are involved in cervical spine motion, stability, and weight bearing. The annular fibers are composed of collagenous sheets called lamellae, which are oriented 65-70° from the vertical and alternate in direction with each successive sheet. Therefore, the annular fibers are prone to injury with rotation forces because only one half of the lamellae are oriented to withstand the force in this direction. [17] The middle and outer one third of the annulus is innervated by nociceptors, and phospholipase A2 has been found in the disc and may be an inflammatory mediator. [20, 21, 22]

 

Several ligaments of the cervical spine, which provide stability and proprioceptive feedback, are worth mentioning. [23, 24] The transverse ligament, the major portion of the cruciate ligament, arises from tubercles on the atlas and stretches across its anterior ring while holding the dens against the anterior arch. A synovial cavity is located between the dens and the transverse process. This ligament allows for rotation of the atlas on the dens and is responsible for stabilizing the cervical spine during flexion, extension, and lateral bending. The transverse ligament is the most important ligament in preventing abnormal anterior translation. [25]

History

Patients with cervical facet joint syndrome often present with complaints of neck pain, headaches, and limited range of motion (ROM). The pain is described as a dull, aching discomfort in the posterior neck that sometimes radiates to the shoulder or mid back regions. Patients also may report a history of a previous whiplash injury to the neck.

Physical

Clinical features that are often, but not always, associated with cervical facet pain include tenderness to palpation over the facet joints or paraspinal muscles, pain with cervical extension or rotation, and absent neurologic abnormalities. Signs ofcervical spondylosis, narrowing of the intervertebral foramina, osteophytes, and other degenerative changes are equally prevalent in people with and without neck pain.

Causes

Bogduk and Marsland studied patients with neck pain without objective neurologic signs to determine if the facet joints were the primary source of their pain. [43] Twenty-four consecutive patients presenting at a pain clinic with neck pain of unknown origin were entered into the study. Those with lower cervical spine pain underwent C5 and C6 medial branch blocks first. If these medial branch blocks did not provide relief, then adjacent levels were blocked until the pain was relieved. Those with upper cervical spine pain underwent third occipital nerve blocks, and then C3 and C4 medial branch blocks if necessary. Bupivacaine was used as the blocking agent and a positive response was considered total pain relief for at least 2 hours. [43]

 

Fifteen patients experienced complete relief of their neck pain, and repeat blocks had the same effect. Seven of these patients underwent intra-articular facet joint blocks, corresponding to the levels determined by the medial branch blocks, which also completely relieved their pain. [43] No clinical or radiologic features corresponded with the positive responses. This finding suggests that facet joints in the cervical spine can be a significant source of neck pain and that medial branch blocks can be used as both diagnostic and therapeutic tools in the management of this type of pain. [43]

 

Each facet joint seems to have a particular radiation pattern upon painful stimulation. Even in subjects without neck pain, stimulation of the facet joints by injecting contrast material into the joints and distending the capsule produces neck pain in a specific pattern corresponding to the specific joint.

 

In a study of 5 such subjects, joint pain referral patterns were mapped out. [44] The C2-C3 facet joint refers pain to the posterior upper cervical region and head, whereas the C3-C4 facet joint refers pain to the posterolateral cervical region without extension into the head or shoulder. The C4-C5 joint refers pain to the posterolateral middle and lower cervical region, and to the top of the shoulder. The C5-C6 joint refers pain to the posterolateral middle and primarily lower cervical spine and the top and lateral parts of the shoulder and caudally to the spine of the scapula. The C6-C7 joint refers pain to the top and lateral parts of the shoulder and extends caudally to the inferior border of the scapula.

 

These pain referral maps were subsequently used to predict the segmental origin of neck pain in 10 symptomatic patients, who were referred for radiologic evaluation of possible facet joint pain. [45] Each of these patients was interviewed before the procedure and recorded the distribution of their pain on a diagram. These diagrams were compared with the maps previously generated from the asymptomatic subjects, and the facet joint or joints thought to be responsible for the pain patterns were predicted. Afterward, the patients underwent diagnostic facet joint nerve blocks at the predicted levels, and the pain was completely relieved in all but one patient. [45] This result suggests that these pain referral maps may be a powerful diagnostic tool when evaluating patients with cervical pain.

 

Facet joint pain referral patterns have also been documented in the OA joint and the lateral AA joint. Dreyfuss et al studied 5 asymptomatic subjects and injected the right AA joint and the left OA joint in each participant with contrast medium to distend the capsule. [46] The resultant pain referral patterns for the AA joints were similar and located posterior and lateral to the C1-C2 segments. The patterns for the OA joints were variable and extended from the vertex of the skull to the C5 segment. Perceived pain was also greater with the OA injections compared with the AA injections. Pain referral patterns have also been documented in symptomatic patients and correspond well to those obtained from asymptomatic subjects. [47]

 

Fukui et al created pain referral patterns from the OA facet joint to the C7-T1 joint.[4] The investigators studied 61 patients with neck pain and stimulated the painful joints by the following 2 methods: injection of contrast medium into the joints and electrical stimulation of the medial branches. Two separate pain referral maps were constructed, and the facet joints and their corresponding medial branches correlated relatively well. [4]

 

Windsor et al electrically stimulated the medial branches of the C3-C8 posterior primary rami with or without the third occipital nerve in 9 subjects. [48] This study demonstrated that the medial branch and third occipital nerve, when stimulated individually, have a separate and distinct referral pattern from the facet joint referral patterns previously mentioned. These medial branch referral maps may provide additional insight in the evaluation of patients with suboccipital, cervical, or shoulder girdle pain.

 
A composite drawing of the referral patterns of 9 A composite drawing of the referral patterns of 9 subjects derived from the minimal threshold stimulation of their right occipital nerve and C3-C8 medial branches
 
 

The alar ligaments run from the lateral aspects of the dens to the ipsilateral medial occipital condyles and to the ipsilateral atlas. The alar ligaments limit axial rotation and side bending. If the alar ligaments are damaged, as in a whiplash injury, the joint complex becomes hypermobile, which can lead to kinking of the vertebral arteries and stimulation of the nociceptors and mechanoreceptors. This may be associated with the typical complaints of patients with whiplash injuries such as headache, neck pain, and dizziness. The alar ligaments prevent excessive lateral and rotational motions, while allowing flexion and extension.

 

The anterior longitudinal ligament (ALL) and the posterior longitudinal ligament (PLL) are the major stabilizers of the intervertebral joints. Both ligaments are found throughout the entire length of the spine; however, the anterior longitudinal ligament is closely adhered to the discs in comparison to the posterior longitudinal ligament, and it is not well developed in the cervical spine. The anterior longitudinal ligament becomes the anterior atlantooccipital membrane at the level of the atlas, whereas the posterior longitudinal ligament merges with the tectorial membrane. Both ligaments continue onto the occiput. The posterior longitudinal ligament prevents excessive flexion and distraction. [26]

 

The supraspinous ligament, interspinous ligament, and ligamentum flavum maintain stability between the vertebral arches. The supraspinous ligament runs along the tips of the spinous processes, the interspinous ligament runs between the spinous processes, and the ligamentum flavum runs from the anterior surface of the cephalad vertebra to the posterior surface of the caudad vertebra. The interspinous ligament and especially the ligamentum flavum control for excessive flexion and anterior translation. [26, 27, 28] The ligamentum flavum also connects to and reinforces the facet joint capsules on the ventral aspect. The ligamentum nuchae is the cephalad continuation of the supraspinous ligament and has a prominent role in stabilizing the cervical spine.

 

Discogenic neck pain

Background

Cervical intervertebral disc disease accounts for 36% of all spinal intervertebral disc disease, second only to lumbar disc disease, which accounts for 62% of all spinal intervertebral disc disease. Cervical problems tend to be less debilitating than lumbar problems, and they do not cause individuals to miss work as often as lumbar spine problems do. [1, 2]

One of 5 visits to an orthopedic practice is for cervical discogenic pain (CDP), with C5-6 and C6-7 accounting for approximately 75% of visits. C7 is the most common nerve root involved. [3] Cervical discogenic pain syndrome (CDPS) presents with proximal symptoms first, and, later, it can progress to brachialgia.

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center. Also, see eMedicineHealth's patient education articles Shoulder and Neck Pain and Neck Strain.

Background

Cervical intervertebral disc disease accounts for 36% of all spinal intervertebral disc disease, second only to lumbar disc disease, which accounts for 62% of all spinal intervertebral disc disease. Cervical problems tend to be less debilitating than lumbar problems, and they do not cause individuals to miss work as often as lumbar spine problems do. [1, 2]

One of 5 visits to an orthopedic practice is for cervical discogenic pain (CDP), with C5-6 and C6-7 accounting for approximately 75% of visits. C7 is the most common nerve root involved. [3] Cervical discogenic pain syndrome (CDPS) presents with proximal symptoms first, and, later, it can progress to brachialgia.

For excellent patient education resources, visit eMedicineHealth's First Aid and Injuries Center. Also, see eMedicineHealth's patient education articles Shoulder and Neck Pain and Neck Strain.

Sport-Specific Biomechanics

Biomechanics is the study of the changes in the anatomic structures occurring during body movements. The movements of the cervical spine include flexion and extension in the sagittal plane, lateral flexion in the coronal plane, and rotation in the horizontal plane. Lateral flexion and rotation occur as coupled movements. Other movements of the cervical spine include protrusion (ie, the head is moved as far forward as possible with the neck outstretched and maintaining forward-facing position) and retraction (ie, the head is moved as far backward as possible and maintaining a forward-facing position).

 

Fifty percent of rotation of the cervical spine occurs in the upper cervical complex with the atlas rotating ipsilaterally around the odontoid. Protrusion causes upper cervical spine extension and lower cervical spine flexion, whereas retraction causes upper cervical spine flexion and lower cervical spine extension. At the occiput-C1 and C1-2 levels, ROM is greater with the protruded and retracted position than with full-length flexion and full-length extension positions. [16] See the image below.

 
Three-dimensional computed tomography scan of C1. Three-dimensional computed tomography scan of C1.
View Media Gallery
 

The annular fibers are made up of collagenous lamellae with alternating directions of inclination oriented 35° from the horizontal. The annulus is more susceptible to injury with rotation and translation movements due to resistance offered only by the lamella oriented in the direction of movement. In the cervical spine, as in the lumbar spine, the intervertebral disc dissipates the transmission of compressive loads throughout the ROM by slowing the rate at which these forces are transmitted through the spine. By diverting the load via temporarily stretching the annular fibers, the disc protects the vertebra from taking the entire load at once.

 

In asymmetric loading, the nucleus pulposus migrates toward the area with less load. Thus, in flexion movements of the cervical spine, anterior offset loading of the intervertebral disc occurs, in which the nucleus pulposus moves posteriorly and the posterior annular wall is stretched. In addition, the cervical lordosis reduces, the vertebral canal lengthens, and the intervertebral foramina open. [2]

 

In extension movements of the cervical spine, posterior offset loading of the intervertebral disc occurs, in which the nucleus moves anteriorly and the anterior annular wall is stretched. Shortening of the vertebral canal and closing of the intervertebral foramen also occur. [2] In lateral flexion and rotation (coupling movement) of the cervical spine, there is offset loading of the intervertebral disc on the side of flexion and rotation, with nuclear material moving to the opposite side (site of the convexity), and the posterolateral annular wall is stretched. [2]

 

The intervertebral foramina house the exiting cervical nerves. The largest cervical spine foramen is at the C2-3 level, and the smallest foramen is at the C6-7 level.[17] The cervical foramina become very dynamic during cervical spine ROM. The intervertebral foramina enlarge with flexion and decrease with extension. In rotation, the ipsilateral side becomes smaller, and the contralateral side enlarges. The extreme changes of the foramina occur with coupled movements (ie, flexion-rotation and extension-rotation-lateral flexion). [18]

 

In addition to the above biomechanical concerns, cervical spinal stenosis has been evaluated with regard to catastrophic cervical sports injuries. The Torg/Pavlov ratio (measured by dividing the sagittal diameter of the spinal canal by the sagittal diameter of the vertebral body) when less than 0.8 was thought to subject the football player to high risk of cervical cord injury due to suspected cervical stenosis (see image below). However, subsequent studies found that this ratio may be erroneously low in players that have wide vertebral bodies. A study by Cantu suggested that functional stenosis as documented by myelogram or magnetic resonance imaging (MRI) may be a more appropriate measure of stenosis. [6]

 
Lateral cervical spine plain radiograph illustratiLateral cervical spine plain radiograph illustrating the Torg/Pavlov ratio.
View Media Gallery
 

Classification of athletic cervical spine injuries

A review by Bailes and Maroon classified athletes with cervical injuries into 3 types [4] :

  • Type I injuries were those that caused permanent spinal cord damage, including conditions such as anterior cord syndrome, Brown-Sequard syndrome, central cord syndrome, and mixed incomplete syndrome.
  • Type II injuries were classified as those that occur transiently after athletic trauma with normal neurologic examination and normal radiologic evaluation. Type II injuries included spinal concussion neurapraxia, and "burning hands" syndrome. The burning hands syndrome was described as suspected injury to the spinothalamic and corticospinal tracts, resulting in arm and hand weakness with burning dysesthesias. [19] This is distinct from the burner or stinger injury that is a common cervical injury in football players and is thought to be due to traction on the upper trunk of the brachial plexus. In this condition, athletes typically have a burning, dysesthetic pain that begins in the shoulder region and radiates unilaterally into the arm and hand, with C5-C6 distribution numbness or weakness.
  • Type III injuries were classified in athletes with only radiologic abnormalities but without neurologic deficit. These included congenital spinal stenosis, acquired spinal stenosis, herniated cervical disc, an unstable fracture, fracture/dislocation, ligamentous injury, and spear-tackler’s spine. Spear tackler’s spine was described by Torg et al described athletes that were at high risk for quadriplegic injury. These athletes had developmental cervical canal stenosis, reversal of the cervical lordosis, preexisting posttraumatic cervical radiographic abnormalities, and documentation of using spear-tackling techniques.

History

Obtaining an accurate history is essential when evaluating patients with neck pain.

  • Identifying specific red flags that are indicators of potentially serious spinal or nonspinal pathology or conditions that may interfere with treatment is extremely important. The absence of red flags diminishes the need for special studies during the first 4 weeks of symptoms, a time in which spontaneous recovery is common. Serious spinal and nonspinal conditions associated with red flags include the following:
    • Cancer/malignancy
    • Infection
    • Trauma with possible underlying fracture
    • Osteoporosis with possible underlying fracture
    • Conditions associated with spine instability (eg, rheumatoid arthritis, Down syndrome)
    • Significant or progressive neurologic deficit (eg, profound muscle weakness and/or reflex loss, bowel and/or bladder incontinence or retention)
    • Vertebral basilar artery insufficiency
    • Pregnancy
  • Obtain an accurate description of the characterization of the pain, including location, onset, duration, frequency, description, distribution, and aggravating and relieving factors.
    • Differentiating between referred and radicular pain is important. Referred pain is more diffuse, whereas radicular pain is more specifically along the course of a dermatome.
    • Patients with disc degeneration could have chronic low-grade pain that is periodically exacerbated for several weeks.
    • Cervical discogenic pain may be localized pain, referred pain, or radicular pain.
    • Mechanical pain can be constant or intermittent, whereas chemical pain is more likely to be constant.
    • Cervicogenic pain is usually worse in positions that involve prolonged sitting, especially in sitting positions with a protruded head posture or prolonged flexion. Bending positions also provoke cervicogenic pain. Frequent changes of position provide relief. However, in cases of severe acute pain, a still position may be most comfortable. Pain worse upon awakening is probably related to using an unsuitable pillow or having adopted an inappropriate posture while sleeping. [2, 20]
    • In 1959, Ralph B. Cloward, MD, published referral patterns of the cervical spine discs using cervical discography. [21]
      • He found that stimulating the anterolateral aspect of the cervical discs produced pain at the ipsilateral scapula. Stimulation in the midline of the anterior aspect of the disc produced pain between the shoulders in the middle of the back. Cloward described that pain from the C6-7 disc was felt in the inferior angle of the scapula. Pain from the C5-6 disc was felt in the center of the medial scapular border. Pain from C4-5 disc was experienced in the region of the spine and superior angle. Pain from the C3-4 disc was referred to the C7 spinous process and the posterior border of the trapezius muscle.
      • Cloward also found that when stimulating patients with posterolateral disc protrusions, the referral patterns were found to be more intense than when stimulating the anterior aspect of the disc and were found to spread from the vertebral border of the scapula out to the shoulder and upper arm as far as the elbow. Midline posterior disc protrusions were found to refer pain to a confined area overlying the fifth cervical to the second thoracic spinous processes near the midline, with upper discs more cephalad and lower discs more caudad. When extensive disc rupture and degeneration were present, a combination of the posterolateral and midline posterior referral patterns was found. [21]
  • Risk factors for malignancy include age older than 50 years, history of cancer, unexplained weight loss, pain with bed rest, and failure to improve with conservative therapy. [22, 23]
  • Ask questions related to potential infection (eg, history of recent surgery, including dental surgery; history of fever or chills; history of intravenous drug abuse) [23]
  • Obtain information regarding the patient's past medical history, including previous neck pain, surgeries, trauma, motor vehicle accidents, and work-related or sports-related injuries.
  • Obtain information regarding a history of alcohol, tobacco, or drug use or abuse; osteoporosis; rheumatologic conditions; diabetes; or other conditions associated with neuropathy (eg, vitamin deficiencies, thyroid disease).
  • Obtain information regarding previous diagnostic studies and treatment interventions.

Physical

See the list below:

  • Physical examination of the patient with cervical discogenic pain includes the assessment for neurologic deficits suggestive of myelopathy.
    • While assessing the patient, look for altered balance, stooped and wide-base gait, weakness, decreased sensation of the upper extremities, lower motor neuron findings in the upper extremities, and upper motor neuron findings in the lower extremities.
    • Patients with a herniated nucleus pulposus (HNP) without radiculopathy can present with limited ROM and referred pain, which may be elicited with the cervical compression test (see image below). Patients with an HNP with radiculopathy may present with limited ROM and radicular pain, dermatomal sensory loss, diminished strength in a myotomal distribution, and loss of muscle stretch reflexes.
      Axial computed tomography scan of cervical herniatAxial computed tomography scan of cervical herniated nucleus pulposus.
      View Media Gallery
    • Manual muscle testing has greater specificity than either reflex or sensory changes. [17, 24] The Spurling test can elicit radicular pain and is performed by having the patient actively extend the neck, laterally flex, and rotate toward the side of the pain. Then, careful downward compression is applied on the head. The Spurling test is helpful in the diagnosis of cervical radiculopathy, because of its high specificity. However, its absence does not preclude the diagnosis of radiculopathy because of its low sensitivity. [17]
  • The Lhermitte test is performed by flexing the neck with the patient in the sitting position. This test may produce an electriclike sensation down the spine and occasionally the extremities. This electriclike sensation has been reported in patients with cervical spondylosis, cervical myelopathy, cervical cord involvement secondary to tumor, and multiple sclerosis. [17]
  • Another helpful clinical sign is pain relief upon arm abduction in cases of a ruptured cervical disc. No changes in pain occur with arm position when the disease process is spondylosis with foraminal stenosis. [25]
  • The neck compression test (Spurling test), axial manual traction, and the shoulder abduction test have high specificity but low sensitivity for the diagnosis of root compression in cervical disc disease. Despite the low sensitivity, these tests are valuable in the clinical examination of a patient with neck and arm pain. [26]
  • The Arm Squeeze Test may be used to differentiate shoulder pain caused by cervical nerve root compression from that caused by shoulder disease. [27]The test involves squeezing the middle third of the upper arm; if pain is elicited from this maneuver, the etiology of the should pain may be cervical in origin. [27]

Causes

See the list below:

  • Degenerative changes
    • Degenerative changes appear early in the lower cervical spine, with the most severe changes occurring at the C5-6 and C6-7 levels. According to Kramer, this is due to the mechanical influence on the cervical intervertebral discs by the extensive movement carried out in the cervical spine in relation to the rigid thoracic spine. [3] Therefore, the comparative loading per squared centimeter by the head on the cervical discs exceeds that of the thoracic and lumbar spine. [3] Cervical spine degenerative changes appear first in the intervertebral discs during the third, fourth, and fifth decades of life.
    • Degenerative disc changes are appreciated by loss of intervertebral disc height and osteophyte development at the origins of the vertebral endplates. These changes lead to loss of shock-absorbing capacity, resulting in abnormal force transmission and increased load to the zygapophyseal joints. Therefore, cervical zygapophyseal joint degenerative changes commonly follow intervertebral disc degeneration. [2, 3] The combination of decreased intervertebral disc space and facet joint degeneration with hypertrophy causes narrowing of the intervertebral foramina, with potential compression of the exiting nerves and associated radicular symptoms.
    • Creep is the further detectable movement that occurs after maximal ROM is attained and a constant force is continued on a collagenous structure. [28] Creep is believed to be due to gradual rearrangement of collagen fibers, proteoglycans, and water content in the ligament or capsule being stressed. As the water content of the nucleus pulposus decreases with disc degeneration and aging, the ability to imbibe water and distribute compressive loads also decreases, [29] resulting in increased creep under compression, which can cause incompetence of the annulus. Hickey and Hukins reported that if ligaments were stretched more than 4% of their resting length, irreversible damage would follow.[30]
    • As disc degeneration continues, the distinction between the margins of the nucleus and annulus becomes obscured. The negatively charged proteoglycan side chains decrease with subsequent loss of their imbibing capabilities. During this process, the overall collagen content within the disc increases. Primary annular disruption initially may occur in the periphery and is referred to as a rim lesion. As the process continues to progress and the margins of the annulus and nucleus coalesce with infiltration of type III collagen, the gelatinous nucleus becomes replaced and the disc essentially becomes fibrotic. [31, 32, 33, 34]
  • Predisposing and precipitating factors for cervical discogenic pain syndrome (CDPS)
    • Predisposing and precipitating factors for cervical discogenic pain syndrome (CDPS) include prolonged sitting with poor posture (eg, protruded head posture), frequent of flexion, sudden unexpected movements, and trauma.
    • Harms-Ringdahl was able to provoke pain in individuals who were asymptomatic by maintaining a protruded sitting posture. [35] All subjects in the study reported neck pain within 2-15 minutes.
    • Static loading with poor sitting or lying postures eventually lead to problems within the cervical spine. Poor posture can also enhance or perpetuate an already existing cervical pain from trauma or whiplash injury.
    • Kramer reported that most patients in his practice developed pain for no apparent reason. [3]
    • Frequent flexion of the cervical spine is another predisposing factor in the production of symptoms from the cervical spine.
    • Sudden unexpected movements, particularly those that involve lateral flexion and rotation of the head and neck with the neck in a protruded position, can cause or precipitate neck pain. Trauma to the cervical spine is commonly seen as a result of whiplash forces occurring during significant motor vehicle accidents or in sports-related cervical spine injuries.