Chapter 11: Neck and Back Pain

David Lipps MD; Charles Brennt, MD

I. CASE HISTORIES

Case 11-1. A 42-year-old previously healthy man complains of a one-week history of left neck, shoulder, and arm pain with numbness in the left hand after lifting a heavy box at work. The pain is worsened by neck extension and coughing. On motor examination he has weakness of triceps, wrist extension, and pronation. Sensory examination shows slight numbness to pinprick in the left middle finger. His reflexes are normal except for absence of the left triceps reflex.

1. Where do you localize his neurologic problem?
2. What are the likely etiologies?

Case 11-2. A 59-year-old woman with steroid-dependent asthma presents with a sudden onset of severe midback pain after a coughing spell. She describes pain radiating into both hips and posterior legs and has noted two episodes of urinary incontinence since the onset of her pain. On examination, she has point tenderness to percussion over T12 and limited range of motion of the spine. Motor strength is normal in the legs with negative straight leg raise test, but she has difficulty walking on her toes. Sensory examination is normal in the legs to pain and temperature, but she has reduced sensation to pinprick in the perennial region and her rectal sphincter tone is reduced. Reflexes are normal except for absent ankle jerks.

1. Where do you localize her neurologic problem?
2. What are the likely etiologies?

II. DISORDERS

The vast majority of cases of neck and back pain are not neurologic injuries at all, but instead represent acute or chronic injuries to the spine and its supportive tissues (intervertebral discs, facet joints, muscles, ligaments, and bony structures). In some cases, however, spinal nerve root or spinal cord tissue may be injured, and it is critical that a physician recognize when injury to these delicate neural structures has occurred since the consequences can be severe and in some cases irreversible.

Table 11-1 Neurologic Disorders Causing Neck/Back Pain

III. HISTORY

There are several key aspects of the neck and back pain history that may help establish the presence of neurologic involvement (Table 11-2).

Table 11-2 Back and Neck Pain: Important Historical Points

Onset and Course of Pain

Acute-onset pain is most often associated with trauma or injury, e.g., flexion-extension injuries (as commonly occur in motor vehicle accidents or "whiplash" injuries), blunt trauma, heavy lifting or strain, bending or twisting injuries, and even violent coughing or sneezing.

Chronic, intermittent pain over weeks, months, or years is most commonly associated with degenerative diseases of the spine, e.g., intervertebral discs, facet processes, or myofascial elements. This type of pain is also commonly brought on by trauma or minor injuries.

Location and Character of Pain

Local pain results from irritation of local sensory nerve endings at the site of involvement and is often due to cutaneous injury, myofascial strain, or vertebral injury (ligament, facet joint, or bone). Local pain can be identified by direct palpation or percussion of the spine and/or its supporting structures. Referred pain is subdivided into two types, (1) that originating in the spine and projected to dermatomes of the cervical, thoracic, lumbar, or sacral region, and (2) pain originating from internal viscera of the chest, abdomen, or pelvis and projecting to the spine. This type of pain is often described as a dull, aching, or squeezing pain but may have sharp or stabbing components at times. Referred pain of cervical spine origin projects to the shoulder, scapula, proximal upper limb, or occipital cranium. Pain of lumbar spine origin projects to the sacrum, buttocks, hip, and proximal lower limb. Radicular pain is caused by compression, stretch, or irritation of the spinal nerve root, most often proximal to or within the intervertebral foramen. Radicular pain has similar characteristics to referred pain but differs in its intensity and its radiation to distal structures. It is described as "stabbing," "electrical," or "like a hot poker" in the distal limb.

Aggravating and Alleviating Factors

Radicular (nerve root) pain will worsen with increased intraspinal pressure (e.g., coughing, sneezing, straining or other Valsalva maneuvers), with upright activities (sitting, standing, and walking), and forward flexion. Referred and local pain of spinal origin remains regionally localized with abrupt Valsalva maneuver. Spinal origin pain is often worse with prolonged sitting or standing and may be relieved with change of position or walking. Those patients who feel better with absolutely no movement are more likely to have a localized process, e.g., pathologic or compression fracture, infection. Both radicular and spinal origin pains are often improved by supine, lateral, and/or fetal positions. Back pain that is present only while lying supine may be due to an extramedullary tumor with spinal fluid block. 

Spinal Nerve Root or Spinal Cord Symptoms

Spinal nerve root dysfunction (radiculopathy) symptoms include sensory changes (numbness, paresthesia, burning), muscular weakness, and radiating pain. Spinal cord dysfunction (myelopathy) symptoms include changes in gait due to spastic weakness in one or both legs, sensory loss on the trunk and back below a specific level of the spinal cord (spinal sensory level), and changes in bowel, bladder, or erectile dysfunction.

IV. EXAMINATION

Table 11-3 Back and Neck Pain: Examination

The examination of the patient with neck and back pain usually begins with inspection and palpation of the spine. With the patient standing, observe for postural changes, signs of spinal deformities (scoliosis, sharp spinal angulation from vertebral collapse, midline dimpling from spinal dysraphism) or malalignments. Palpate for muscle spasm, trigger point zones, or sciatic notch tenderness and apply light percussion for facet joint, sacroiliac, or spinal tenderness. Check for spinal movement and range of motion with flexion, extension, lateral bending and rotation.

Secondly, have the patient walk (see chapter 8). In patients with neck pain, spinal cord involvement may be indicated by a stiff-legged spastic gait (see Chapter 8) with a circumducting or scissoring gait. While low back pain may limit gait testing, it is important to try to test toe and heel walking. Toe walking can test for calf strength and S1 root integrity, while heel walking tests L4 and L5 root distribution muscle strength.

With the patient seated, check motor strength in extremities (see chapter 10), looking for nerve root (Tables 11-4 and 11-5) or upper motor neuron (spinal cord) patterns of weakness or muscle atrophy. Similarly, the goal of the sensory examination (chapter 10) is to localize any neurologic impairment. A sharp object such as pin or paper clip point may be used to isolate a dermatomal sensory loss indicative of a nerve root lesion. Spinal cord involvement may produce a sensory level on the back. If a level is established, look for an asymmetry of sensory loss indicating a Brown-Sequard syndrome. Testing for proprioception (position sense) of the hands and feet may be useful to identify posteriorly placed cord lesions. Deep tendon reflexes and plantar reflexes should also be done at this point. Spinal nerve root involvement will typically cause a reduction or absence of the corresponding level reflex (Tables 11-4 & 11-5), while spinal cord injury will produce hyperreflexia and extensor plantar reflexes.

With the patient supine, the straight-leg-raising test (Video 11-2)may be performed to elicit nerve root or radicular pain by passively lifting the patient's heel and then gently dorsiflexing the foot, thereby stretching the entrapped or injured nerve root, radicular symptoms are reproduced. By then flexing the leg at the knee and relieving the sciatic nerve tension, the hip can be internally and externally rotated to evaluate primary hip disease. A rectal examination to evaluate sphincter tone may be done at this time, if clinically appropriate.

Table 11-5 Neurologic Signs and Symptoms of Lumbar Root Injury

VI. RED FLAGS AND WHEN TO REFER

Nontraumatic causes of acute onset pain are far less common and should be a red flag for more ominous pathologies, including pathologic compression fractures, epidural infections, spontaneous rupture of spinal arteriovenous malformation, or intramedullary cord tumors with spinal fluid block. A history of cancer, human immunodeficiency virus,, immunosuppression, or systemic disorder should be elicited. Subacute nontraumatic causes may also include a spinal tumor, epidural mass, or transverse myelitis. Acute-onset neck or back pain associated with myelopathic symptoms (significant bilateral weakness, gait changes, bowel/bladder signs, spinal sensory level) must always be treated as a medical emergency. Emergent evaluation usually involves imaging of the spine with magnetic resonance imaging (MRI). It is important to remember that when suspecting a spinal cord lesion, MRI scanning should be directed not only at the level of the suspected lesion, but also above it. For example, a patient who on examination has a spinal sensory level at T5 may have a cord lesion in the thoracic spine or in the cervical spine, so the initial imaging should be directed at both cervical and thoracic spines. Computed tomography (CT)-myelography may be an appropriate alternative in cases where MRI is contraindicated or impossible (morbidly obese patients or those with pacemakers or other implanted electronics). In cases of acute-onset neck/back pain while lifting with subtle or no sensory, motor, or reflex changes, conservative management of pain for 10 to 20 days may be considered, and if neurologic signs persist or worsen, spinal imaging would then be indicated. For patients presenting with subacute or chronic intermittent pain who have myelopathic symptoms or signs, imaging referral should be within 72 hours of evaluation. Patients with known history of cancer or immunodeficiency states who present with acute or chronic progressive back pain associated with spinal cord sign or symptoms should be urgently evaluated. Patients with chronic back pain and signs or symptoms of radiculopathy should be referred within two weeks of evaluation. Electromyography may be indicated if the differential includes nerve root injury, diabetic polyradiculopathy, and/or peripheral neuropathy. Electromyography may be falsely negative if performed within the first three weeks after the onset of symptoms.

Slowly progressive and unrelenting pain is another potential red flag for more serious pathology, including intra- or extramedullary tumors, or chronic infectious etiologies. Constant pain can also represent referred pain from within the spine or internal viscera.

VII. CASE DISCUSSIONS

Case 11-1. This patient has neurologic signs and symptoms that are consistent with an acute C7 radiculopathy. The most likely etiology, given the history of preceding trauma (lifting of a heavy box) is a herniated intervertebral disc at the C6-C7 level with compression of the left C7 nerve root within the intervertebral foramen. One might consider ordering an MRI of the cervical spine or referring the patient to a neurologist.

Case 11-2. The history of acute-onset severe back pain in association with a change in bowel or bladder function is a red flag for possible spinal cord injury. In this case, a middle-aged woman with steroid-dependent asthma is very likely to have spinal osteoporosis, and a pathologic compression fracture of the spine might be expected, especially after trauma (in this case because of a coughing spell). The presence of point tenderness over the lower thoracic region helps to localize the lesion to the T12 level, which is the location of the conus medullaris (the spinal cord ending at the lower body of L1 vertebra). The neurologic examination reflects injury to the conus medullaris due to sensory loss in the perineal region, and reduced rectal tone. The presence of reduced patellar reflexes and decreased toe walking suggests some involvement of the S1 proximal roots at this level. This case represents a potential neurologic emergency due to the presence of acute spinal cord dysfunction. This case might require surgical intervention, and an emergent referral to neurosurgery would be indicated.

VIII. CME QUESTIONS

1. Radicular pain is similar to referred pain except that:

a. It is associated with numbness in a nerve root distribution.
b. It is more intense in severity.
c. It may be associated with motor weakness in a nerve root distribution.
d. It worsens in the distribution of a specific nerve root with cough or Valsalva maneuvers.
e. All of the above.

2. A 45-year-old man presents with three-week history of low back and left leg pain. The pain radiates into the left first toe when he bends forward or coughs .On examination, he has weakness of left foot and first toe dorsiflexion and numbness in the left distal lateral calf and dorsum of the foot. His knee and ankle reflexes are normal. Which of the following is the most likely diagnosis?

a. Conus medullaris syndrome
b. Left L4 radiculopathy
c. Left L5 radiculopathy
d. Lumbar strain

3. A 58-year-old woman with a history of metastatic breast cancer to the lung presents with a three-day history of worsening upper back pain, weakness of both legs, and numbness from the chest level down. The following are true except:

a. She does not need to be treated as a medical emergency.
b. She is likely to have compression of her cervical or thoracic spinal cord.
c. She may develop bowel or bladder incontinence.
d. She will require an emergent MRI scan of her spine.

4. A 49-year-old obese man presents with a two-day history of low back pain radiating into both buttocks and posterior thighs. Pain is worse with prolonged sitting or standing but improved with ambulation. Cough or strain causes minimal increase in pain in the back. On examination he has tenderness throughout the lumbar region to palpation and moderate muscle spasm. Neurologic examination is normal. The following are true except:

a. The patient can be treated conservatively for pain for 10 days.
b. The patient most likely does not have a significant nerve root injury.
c. The patient most likely has lumbar degenerative spine disease with referred pain to the posterior legs and buttocks.
d. The patient needs an emergent MRI scan of the lumbar spine.

5. A previously healthy 35-year-old woman presents with a one-week history of progressive weakness in both legs with clumsy gait and episodes of urinary urgency and occasional incontinence. She complains of tingling and numbness on her left side from an area just below her left breast down to her foot, which is worse with neck flexion. She notes a nagging chronic pain in her low back since a motor vehicle accident six months ago.

On neurologic examination she has weakness in right hip and knee flexion and right foot drop. Her reflexes are hyperactive in both lower extremities with a Babinski sign on the right. Her sensory examination is consistent with a T5 sensory level with numbness to pin prick and temperature on the left. Her gait is stiff legged and spastic. All of the following are true except:

a. MRI or CT-myelogram of the spine must include cervical and thoracic spinal imaging since the lesion in question could be at the thoracic level or above.
b. MRI or CT-myelogram of the thoracic and lumbar spine should be adequate to identify the pathology in question.
c. The patient's chronic low back pain is likely to be of non-neurologic origin and unrelated to her current symptoms of leg weakness and numbness.
d. The patient's history and examination are consistent with an acute myelopathy and should be treated as a medical emergency.

CME ANSWERS

1. e. All of the above

2. c. Left L5 radiculopathy

3. a. She does not need to be treated as a medical emergency

4. d. The patient needs an emergent MRI scan of the lumbar spine

5. b. MRI or CT-myelogram of the thoracic and lumbar spine should be adequate to identify the pathology in question