Chapter 7: Approach to Neck and Back Pain

Neck and back pain are common presenting complaints in emergency department patients. Approximately 70% to 90% of individuals will experience an episode of back pain at some point in their lifetime.^1–3 In a survey, 26% of individuals reported low back pain and 14% reported neck pain within the previous 3 months.⁴ In addition to being common, back pain is costly: spine-related expenditures have been increasing in recent years, costing $86 billion in the United States in 2005.^5,6 In addition, indirect costs related to days lost from work are substantial, with approximately 2% of the US work force compensated for back injuries each year.⁷

The literature reports that an estimated 85% of patients have pain secondary to muscle or ligamentous injury and only a minority of patients have pain because of nerve roots (e.g., herniated disk), facet joints (e.g., arthritis), or the bone (e.g., osteomyelitis).¹ It is the author’s opinion that this imbalance is greatly exaggerated because the majority of muscle spasm and strain is secondary to another injury or disorder that is the primary cause of the pain. This chapter attempts to provide the reader with the tools to better ascertain the difference between these entities. Chapter 8 goes into further details regarding each of these diagnoses, whereas Chapters 9 and 10 focus on the traumatic injuries of the cervical and thoracolumbar spine, respectively.

Whether the exact cause of the patient’s pain can be determined or not, the ability to differentiate life-threatening from benign causes is of paramount importance to the emergency physician. When evaluating a patient with back pain, clinicians should ask themselves two important questions:

1. Is there a serious underlying systemic disease responsible for the pain?

2. Is neurologic compromise present that would indicate spinal cord injury and necessitate further imaging and surgical consultation?

The spinal column includes 33 vertebrae: 7 cervical, 12 thoracic, and 5 lumbar (Fig. 7–1). The sacrum consists of five fused vertebrae and the coccyx. The first two cervical vertebrae, the atlas (C1) and axis (C2), are unique. The atlas is a ring-like structure that articulates with the skull, where it is responsible for 50% of the neck’s ability to flex and extend. The odontoid process of the axis is secured to the anterior portion of the atlas and allows rotation.

The vertebral bodies gradually increase in size as they descend. The posterior arch encases the spinal cord and consists of the broad pedicles, flat laminae, and the spinous processes (Fig. 7–2). The transverse processes extend laterally near the junction of the pedicles and laminae. The posterior arch has four facets that articulate with the superior and inferior vertebrae forming synovial joints. Depending on their location, the transverse processes articulate with the ribs.

The ligaments of the spine include the anterior and posterior longitudinal ligaments that interconnect the vertebral bodies and run the length of the spine. Posteriorly, the ligamentum flavum, interspinous ligament, and supraspinous ligament provide stability.

Although the vertebrae provide support and protection of the spinal cord, ligaments and intervertebral disks account for the spine’s flexibility. In the cervical and lumbar spine, flexibility is greatest, whereas the thoracic spine ligamentous structures promote stability. The sections of the vertebral column with the greatest mobility also are the location of the greatest frequency of injury. The most common location for spinal cord injury is in the cervical spine between C5 and C6.

The intervertebral disks are composed of the nucleus pulposus at the center surrounded by the annulus fibrosus. In the cervical and lumbar spine, the disks are thicker than the thoracic spine and therefore promote flexibility in these regions. With age, small tears occur in the annulus fibrosus that begin centrally and radiate to the periphery. With a sudden increase in pressure, the annulus fibrosus can completely tear and the nucleus pulposus herniates. Herniation is less common in individuals older than 50 years because the nucleus pulposus is desiccated and fibrotic.

The spinal canal and cord are largest in the cervical region. In the thoracic spine, the spinal canal is very narrow and therefore, small displacement can lead to significant neurologic injury (i.e., cord transection). The nerve roots exit the spinal foramina laterally. Cervical nerve roots emerge above the corresponding vertebrae, whereas the opposite is true of thoracolumbar nerve roots. This is because there are eight cervical nerve roots and only seven cervical vertebrae (Fig. 7–3). In the adult, the spinal cord ends at the L1-2 interspace where the remaining nerve roots make up the cauda equina. The cauda equina loosely fills the remainder of the spinal cord and tolerates compression better than the spinal cord itself.

Although the differential diagnosis for back pain is lengthy, screening patients who may be suffering from conditions that produce significant morbidity and mortality is of the utmost importance. A systematic approach to identifying the potential etiologies of back pain is to categorize the source of pain as vascular, visceral, infectious, mechanical, and rheumatologic. More than 85% of patients presenting to primary care settings have low back pain that is not attributed to a specific disease or spinal abnormality, and is subsequently diagnosed as nonspecific low back pain.⁸ Therefore, there is a high “noise to signal ratio” that the clinician must differentiate to identify life-threatening causes of back pain. Disorders such as spinal epidural abscess or hematoma, malignancy, spinal fractures, thoracic aortic dissection, ruptured aortic aneurysms, compressive mass, spinal column injury with or without cord compression, and cauda equina syndrome, while less common, frequently require emergent treatment. As such, a delay in diagnosis can be problematic. This section will discuss a general approach to aid the clinician in diagnosing these potentially life-threatening conditions. It will highlight the importance of recognizing “red flags” that may indicate the presence of a diagnosis that requires urgent or emergent diagnosis and treatment (Table 7–1).

The patient’s age is the first clue in helping to differentiate the etiology of back pain. In patients younger than 20 years, back pain in the absence of trauma suggests spondylolisthesis or spondylolysis.² Herniation of a disk occurs most commonly in patients aged 30 to 50. Patients older than 50 years account for over three-quarters of malignancy-related causes of back pain.⁹ Elderly patients are at a higher risk for malignancy, aneurysm, and fracture. Most patients with compression fractures are older than 70 years.

The clinician should ask the patient to describe how and when the pain began, what they were doing at that time, and whether they have had previous episodes of similar pain. Inquire if there was an inciting event that produced immediate back pain such as lifting and/or twisting while holding a heavy object, prolonged sitting, motor vehicle collision, or fall, all of which suggest a musculoskeletal cause of pain such as muscular strain or disc herniation. A gradual onset of pain over a period of weeks to months is concerning for malignancy or infection. Because the majority of patients with back pain improve over a 4- to 6-week period, pain that has been persistent for greater than 6 weeks also raises a concern for malignancy or infection. Pain following a fall, especially in an elderly patient, suggests a possible fracture. In patients who sustain a more significant traumatic injury, a fracture should be considered until proven otherwise.

Clinicians should also consider risk factors for vertebral compression fracture, such as older age, history of osteoporosis, and steroid use, as well as risk factors for ankylosing spondylitis, such as younger age, morning stiffness, improvement with exercise, alternating buttock pain, and awakening due to back pain during the second part of night only.¹⁰

The location of pain should be noted. Pain in the paraspinal area suggests muscular injury, but may be secondary to another underlying disorder of the back. Midline pain is seen in fracture, malignancy, or infection. Caution is required here, however, because serious causes may present with paraspinal muscle spasm. Back pain in the lumbar region is most common, but thoracic back pain is potentially more concerning. It may suggest conditions such as aortic dissection, malignancy, or spinal infection.²

It is particularly important to elicit “red flag” symptoms from the history to risk stratify for etiologies of back pain that are surgical emergencies, specifically cauda equina syndrome. It is important to document the presence or absence of bowel or bladder dysfunction, which may be a symptom of severe compression of the cauda equina by a tumor or massive midline disk herniation. In this condition, urinary retention with overflow incontinence is typically present (90% sensitivity), and can often be associated with saddle anesthesia, bilateral sciatica, or leg weakness.¹⁰

Exacerbating and alleviating factors also provide clues to the etiology. Pain that persists at rest or is worse at night may herald an underlying malignancy or spinal infection because musculoskeletal pain usually gets better with rest. Specific positions that exacerbate the pain may also suggest the etiology. An increase in pain in the prone position is seen in lateral disk herniation. Pain increased by extension suggests facet syndrome, central stenosis, or lateral herniation. Pain increased by sitting is usually suggestive of an annular tear in the disk or a paramedian herniation. Standing up from a seated position will make pain worse in patients with discogenic pain. Ambulation usually makes the pain of spinal stenosis worse, whereas bending over improves the pain. If coughing or any other Valsalva maneuvers make the pain worse, this suggests a herniated disk.

Radiation of pain down an arm or leg is suggestive of a radiculopathy. The most common cause is a herniated disk compressing the nerve root, but spinal stenosis, malignancy, and infection can also cause a compressive radiculopathy. In patients with a lumbar radiculopathy, sitting, coughing, or straining make the symptoms worse, whereas lying flat improves the pain. More than 90% of symptomatic lumbar disc herniations occur at the L4/5 and L5/S1 levels, resulting in pain that radiates down the leg and past the knee (sciatica). Although radiculopathy is present in only 1% of patients with low back pain, its absence makes a clinically important disk herniation unlikely. A patient that complains of unilateral lower-extremity weakness should be of particular concern. Differentiating true loss of muscle strength from the inability to perform muscle function secondary to pain is difficult, but crucial. This distinction should start with the history by not only asking the patients, but also observing their movements. Did they walk into the emergency department or to the bathroom?

During the review of symptoms and past medical history, the physician should inquire about symptoms that might raise the clinician’s suspicion that a significant underlying condition is causative. Weight loss, fevers, immunocompromised status (HIV, chronic steroid use) or a history of intravenous drug use raise concern for an infectious cause of the pain. Approximately 40% of patients with spinal infection have an identifiable site of infection elsewhere such as a urinary tract infection or cellulitis.¹¹ Two-thirds of patients with spinal epidural metastases will have a history of cancer. The most common cancers that metastasize to spine include breast, lung, prostate, kidney, and thyroid carcinomas, therefore patients with a history of one of these malignancies should elicit heightened alarm for a non-mechanical etiology of back pain.¹²

The clinician should also consider a referred source of back pain because of conditions in the abdominal cavity and retroperitoneum (Tables 7–2 and 7–3). Identification of these entities by eliciting other clues from the patient’s history requires a high index of suspicion by an astute clinician.

The examination of a patient with back pain begins with an assessment of the vital signs. Although hypertension should raise the suspicion for aortic dissection, hypotension in the presence of back pain suggests an abdominal aortic aneurysm until proven otherwise. In the setting of trauma with spinal cord injury, consider neurogenic shock as a possible cause of hypotension once hemorrhage has been excluded. A fever is important to note; however, its absence does not exclude a significant infection. For example, one-half of patients with pyogenic osteomyelitis do not have fever.¹³

A complete physical examination should be performed with particular attention to the heart, pulses, lungs, abdomen, and skin, followed by detailed musculoskeletal and neurological examinations. Decreased breath sounds may suggest a malignancy-related effusion; rales or rhonchi may suggest pneumonia or other active infection. Cardiovascular examination including peripheral pulse examination should be completed to assess for asymmetry of peripheral pulses or upper-extremity blood pressures, which would raise concern for aortic dissection. The abdominal examination should assess for the presence of a pulsatile mass, which would suggest an abdominal aortic aneurysm. It is important to perform a rectal examination in order to assess for loss of rectal tone or perianal anesthesia, especially when cord compression is considered on the differential. A thorough examination of the skin may reveal evidence of the early lesions of herpes zoster. Neurological examination should include full assessment of strength, sensation, and reflexes, as well as rectal tone and perianal sensation in appropriate patients. Further discussion of neurological and musculoskeletal examinations is detailed below.

Cervical Spine Examination

Inspection starts by looking for scars, ecchymoses, or erythema. In the nontraumatic setting, the normal lordosis of the cervical spine is best seen from the side of the patient. If Valsalva or compression on the top of the head reproduces pain, there is likely a herniated disk or spinal stenosis affecting the diameter of the spinal canal or foramina.

In the cervical spine, the muscles are relaxed in the supine position, making the deeper bony and ligamentous structures more readily palpable in this position. The examiner begins by feeling the occiput and the base of the skull in the midline. The posterior bony structures are best palpated if the examiner stands behind the patient’s head and cups the hands under the neck so that the fingertips meet at the midline (Fig. 7–4). The first structure noted is the spinous process of the axis (C2). The posterior arch of C2 is not palpable. In the thin patient, the examiner should be able to feel all the spinous processes of the cervical spine. Loss of alignment is seen in unilateral facet joint dislocation or with a fracture.

C7 (and sometimes T1) has the largest spinous process in most individuals and is a helpful landmark. Other landmarks in the cervical spine include the thyroid cartilage, which overlies C4 and C5, and the cricoid cartilage that is at the level of C6. The facet joints are palpated lateral to and between the spinous processes on each side. In the relaxed neck, they feel like a small dome. Tenderness over the facet joints suggests arthritis, fracture, or ligamentous injury.

The neurologic examination should include an assessment of motor strength, sensation, and reflex testing. The location of cord injury can be determined by knowing how-to-test function at that level. In the cervical spine, C5 to C8 are most commonly affected (Table 7–4 and Figs. 7–5 to 7–8).

Thoracolumbar Spine Examination

The thoracolumbar examination should proceed in a systematic manner for both efficiency and completeness. The complete examination of the spine in the nontraumatized patient will be reviewed in this section, but depending on the clinical scenario, the clinician will not need to perform all of the maneuvers described.

Standing

If the patient is able to stand, the examination begins in this position with inspection. Note the normal lordosis of the lumbar spine. Straightening of the lumbar spine might suggest ankylosing spondylitis or paravertebral muscle spasm. Next, check the alignment of the back from behind the patient. Over half of patients will have abnormalities of alignment that may contribute to back strain. The first thoracic vertebrae should be centered over the sacrum, and the posterior superior iliac spines (PSIS) should be equal in height.

The sacroiliac (SI) joint is assessed by placing one thumb on the PSIS and the other on the spine of the sacrum. After asking the patient to raise the ipsilateral leg off the ground, determine if the PSIS moves down (normal) or up (SI joint pathology). In addition to assessing the SI joint, raising one leg while extending the back will exacerbate back pain in patients with facet joint disease or spondylolisthesis. If the patient prefers to stand leaned over slightly to one side with the hip and knee flexed, this suggests sciatic nerve irritation, most commonly from a herniated disk.

Range of motion in flexion and extension does not reliably distinguish among pathologic causes, but can provide a baseline to evaluate for therapeutic response. Normal range of motion of the back involves 40 to 60 degree of flexion. If the lumbar spine maintains its lordosis and flexion occurs at the hips when the patient bends forward, pathology of the lumbar spine, usually at the L4-5 or L5-S1 interspaces, should be suspected. Pain with flexion is consistent with sciatica, disk herniation, or lumbar strain. Normal extension of the lumbar spine is 20 to 35 degrees. Extension stresses the facet joints and narrows the foramina through which the nerve roots exit. Painful extension, therefore, is characteristic of facet joint pathology and arthritis.

Palpation of the spine is ideally performed in flexion. The spinous processes of the thoracolumbar spine are easily palpated except in extremely obese patients. Any lateral deviation of these processes suggests rotational deformity such as scoliosis or fracture. The distance between the spinous processes should be equivalent from one segment to the next. The supraspinous and interspinous ligaments are palpated in the recesses between the spinous processes (Fig. 7–9). Some helpful landmarks to remember include the iliac crests at the level of the L4 and L5 interspace and the S2 spinous process at the level of the PSIS (Fig. 7–10).

Pressure on the spinous processes is transmitted anteriorly to the arches and toward the vertebral bodies. For that reason, percussion of the spinous processes with a reflex hammer may aid in differentiating pain from the vertebral column versus deeper retroperitoneal structures. Generally, pain with percussion suggests spinal pathology such as a fracture or infection. Tenderness to percussion over the spine is 86% sensitive for bacterial infection, but is only 60% specific.^9,14.

The facet joints are located approximately 3 cm lateral to the spinous processes in the thoracolumbar region. Like the cervical spine, the facet joints are both lateral to and between the spinous processes. Direct palpation of the facet joints is not possible in the thoracolumbar spine because they are deep to the paraspinous muscles.

Lastly, while the patient is still standing, have the patient stand on their heels to test the motor function of the L5 root and stand on tip toes to test the S1 root.

Supine

Once the patient is lying supine, perform a straight-leg raise test and crossed straight-leg raise test. With the knee extended, the leg is raised gradually. Pain before 30 degree of elevation is not consistent with nerve root irritation because only the dura is being stretched until this point. Elevation from 30 to 60 degree stretches the nerve root and reproduces pain due to a herniated disk (Lasègue’s sign). For either test to be considered positive, the pain must radiate beyond the knee. A positive straight-leg test is sensitive, but not specific, for herniated disc. The crossed straight-leg test is less sensitive for herniated disks, but 90% specific.¹⁵ An increase of pain with the Valsalva maneuver is also sensitive for sciatic nerve irritation.

The FABER (flexion, abduction, and external rotation of the hip) test for pathology of the hip and SI joints is also performed in the supine patient. The foot of the affected side is placed on the opposite knee. Pain in the groin suggests pathology of the hip, not the spine. Gentle, but firm, downward pressure on the flexed knee and opposite anterior superior iliac crest produces SI joint pain in patients with pathology there.

The majority of the neurologic assessment can be performed while the patient is lying supine. The neurologic examination should include an assessment of motor strength, sensation, and reflex testing. The location of cord injury can be determined by knowing how-to-test function at that level. In the lumbar spine, the L3, L4, L5, and S1 nerve roots are tested (Table 7–5 and Figs. 7–11 to 7–13). L5 motor nerve root testing evaluates strength of ankle and great toe dorsiflexion. L5 sensory nerve root damage would result in numbness in the medial foot and the web space between the first and second toe. The S1 nerve root is tested by evaluating ankle reflexes and sensation at the posterior calf and lateral foot. S1 radiculopathy may cause weakness of plantar flexion.¹⁵ The ability to squeeze the buttocks together (i.e., gluteus maximus) is an additional reliable motor finding of the S1 nerve root.

One neurologic test that is frequently overlooked, but often diagnostic, is vibratory sensation. A tuning fork is placed over a bony prominence supplied by the nerve root (e.g., medial malleolus for L4, patella for L3). The vibration will elicit discomfort that radiates upward to the back in the sensory distribution of the irritated nerve root. Vibratory sense is the most superficial layer of the nerve and thus is the most sensitive when there is early compression.

When attempting to determine the location of neurologic injury, several general principles are useful. Unilateral weakness suggests a radiculopathy, whereas bilateral weakness or spasticity is characteristic of a lesion within the spinal cord (i.e., myelopathy). Cauda equina syndrome should be suspected in patients with lower motor neuron findings, bilateral leg weakness, loss of rectal tone, saddle anesthesia, and urinary retention. Sensory deficits within a single dermatome support a radicular source of pain, whereas involvement of multiple dermatomes is more likely to be due to pathology within the cord (Fig. 7–14).

Prone

Test the S1 nerve root by noting the function of the gluteus maximus muscle. Ask the patient to clench the buttocks together. If one side is weaker, there is likely a deficit of the S1 nerve root.

Perform the femoral stretch test by extending the hip in the prone position. This maneuver produces pain lateral to the midline in patients with facet joint pathology. Pain produced in the anterior thigh, however, suggests irritation of the L2-3 nerve roots.

Next, palpate the area of the sciatic nerve as it courses between the ischial tuberosity and the greater trochanter. If this produces tenderness, irritation of the nerve in this location should be suspected as opposed to irritation in the back. Piriformis syndrome is a cause of sciatic nerve irritation in this position and is covered in further detail in Chapter 17 “Pelvis.”

A sheet placed under the umbilicus in the prone patient will flex the lumbar spine and make the facet joints more apparent. The spinous processes should be equidistant. A step-off between L5-S1 and L4-L5 suggests spondylolisthesis. As in the standing patient, tenderness 3 cm lateral to the spinous process suggests facet joint pathology.

Because most patients with back pain recover uneventfully, extensive imaging studies are not routinely recommended. Joint guidelines from the American College of Physicians and the American Pain Society (2007) recommend that routine imaging not be obtained in patients with nonspecific low back pain and that imaging be reserved for patients with severe or progressive neurologic deficits, trauma, or when serious underlying conditions are suspected on the basis of history and physical examination.¹⁶ Table 7–6 identifies eight “red flags” which may be helpful in identifying patients in whom imaging should be considered.

Plain films are indicated following trauma or as a screen for a pathologic fracture in selected high-risk patients such as those with osteoporosis or steroid use. In the spine, the anteroposterior, lateral, and oblique views are routine. The odontoid (open-mouth) view is unique to the cervical spine and allows for better visualization of C1 and C2.

MRI or CT imaging is recommended in patients who have severe or progressive neurologic deficits or who are suspected of having a serious underlying condition (such as vertebral infection, cauda equina syndrome, or cancer with impending spinal cord compression), as these are emergent diagnoses. CT scan may demonstrate intervertebral disk disease or a tumor if it is large enough. It is not sensitive enough to diagnose spinal malignancy. MRI is the diagnostic test of choice for visualizing the spinal cord, vertebral marrow, and soft tissue.¹⁷ It is emergently indicated when compression is suspected. It provides good definition of the disks, spinal cord, and nerve roots. MRI is up to 96% sensitive and 94% specific for diagnosing vertebral osteomyelitis.¹⁸

For patients with acute back and radicular pain but no motor weakness, and for those with chronic low back pain without neurologic deficit, obtaining MRI and CT does not improve outcome.¹⁹ Anatomic evidence of a herniated disk is present in 20% to 30% of MRIs in asymptomatic patients. The findings of herniated disks and spinal stenosis in many asymptomatic individuals indicates that imaging alone can be misleading.¹

The treatment of back and neck pain is dependent on the cause. Any patient with significant trauma, impaired consciousness, or neurologic deficits should have spinal precautions instituted with a cervical collar and back board in the emergency department, if not already performed in the prehospital setting. For information regarding the specific treatments of emergent conditions that cause back pain in the absence of trauma refer to Chapter 8. Further treatment guidelines for patients with cervical and thoracolumbar trauma are presented in Chapters 9 and 10.