Back and Neck Pain
Shamik Bhattacharyya
LOW BACK PAIN
Background
1. Back pain is common in general and neurologic practice. Half of the adults have experienced mild to moderate back pain at some time, many of whom were unable to work as a result.
2. Many patients with back pain do not seek medical care at all. Those who see a neurologist have generally been evaluated by other practitioners such as primary care.
3. The majority of chronic low back pain has a mechanical basis in musculoskeletal spinal disease of the joints, discs, bones, ligaments, and muscles.
4. The examination for back pain infrequently reveals a specific diagnosis. Directed history for “red flags” often exposes the more serious causes.
History
1. Chronic back pain
a. The typical symptom is chronic “aching” in the low back, most often in the region of the lower lumbar spine. The pain can extend into the lower thoracic region superiorly and into the buttocks/proximal legs inferiorly. There are often activities that provoke sharp exacerbations to the background achy pain.
b. Aching pain may be worse on awakening or increase through the day with activity or after prolonged sitting. Both are characteristic of benign “arthritic” causes.
c. Chronic low back pain from degenerative disease displays little limitation of motion, but there may be broad areas of tenderness over the muscles, ligaments, and joints throughout the low back.
d. Severe osteoporosis or osteopenia gives rise to vague, relatively constant low back pain, but the majority of patients with these processes do not have pain.
e. Nocturnal pain, especially pain that awakens the patient in the middle of the night, alternating buttock pain, or progressively escalating pain over the course of a month are “red flags” suggesting potential secondary causes of back pain requiring further investigations.
f. A history of active cancer, fever, night sweats, weight loss, recent bacteremia, HIV, or pulmonary tuberculosis suggests infectious or neoplastic infiltration of the spine.
g. Lumbar stenosis (see further on) is a disease of the older population, characterized by aching back pain and claudication-type sciatic and leg pain that is induced by walking and relieved with rest.
h. Leg weakness, sensory changes in the legs or trunk, and bladder dysfunction indicate compression of the spinal cord or cauda equina and are not consistent with the nondescript types of back pain discussed here.
i. Persistent and increasing lumbar pain of recent onset without a history of recurrent discomfort earlier in life compels consideration of retroperitoneal disease including renal cell cancer, pancreatic cancer, duodenal ulcer, abdominal aortic dissection, and retroperitoneal hematoma.
2. Acute back pain
a. Sudden mechanical injury from awkward positioning, being thrown or falling, lifting, and trauma elsewhere in the body are the main causes of acute back pain, called “strain.” Pain may be delayed by hours after the inciting event.
b. Lumbar disc rupture may cause acute back pain at the time of the event. The pain is often lateralized. However, magnetic resonance imaging (MRI) of lumbar spine acutely even with severe low back pain may not show a clear cause.
c. In acute low back strain, there is a disinclination to bend, twist, or extend the lower torso and the paraspinal muscles, accompanied by the assumption of protective postures of the trunk, and there may be palpable muscle spasm.
d. In adolescents, acute low lumbar pain after minor injury may indicate spondylolysis, a congenital weakness of the pars interarticularis that is prone to fracture usually at L5.
e. Focal thoracic or lumbar back pain may be the result of a compression fracture. Usually, there has been a fall on the buttock or back, but major injury is not necessary if the bones are osteopenic.
f. Severe pain after direct trauma to the spinal column or head is a more serious matter of specialized nature because of potential disruption of the ligaments and supporting bony structures that result in instability of the spinal column.
g. As with chronic back pain described earlier, leg weakness, sensory changes in the legs or trunk, and bladder dysfunction indicate compression of the spinal cord or cauda equina and are not consistent with the nondescript types of back pain discussed here.
h. Disc rupture causes projected pain along the distribution of the adjacent nerve root: For example, L5 rupture is perceived as sciatica; there may also be acute pain over the L5 to S1 facet joint.
Pathophysiology
1. The pain-sensitive structures that generate low back pain include free nerve endings in the periosteum, capsule of the facet joints, and annulus surrounding the disc.
2. The origin of most chronic low back pain is arthritis involving the facet joints, discs, and degeneration of the spinal ligaments.
3. There is frequent disc desiccation at affected levels accompanied by degenerative arthritic changes leading to hypertrophy of the bone surrounding the facet joints and, in advanced cases, loosening of the structural elements that maintain alignment of the spine.
4. The resultant instability may lead to spondylolisthesis, or slippage of one vertebral segment upon an adjacent one. This results in malalignment of the spine, narrowing of the spinal canal, and compression of the cauda equina roots that may itself cause pain.
5. Pain referred to a distant site from bony or disc disease is termed “sclerotogenous” and has a distribution that approximates neurogenic “referred” pain from root compression, but it tends to be less severe, fluctuates more, and is vaguer in localization.
6. Much back pain is described as “muscular” and is located in the paraspinal muscles; it has been presumed that pain receptors in the muscle contribute to discomfort.
7. A relationship of chronic low back pain with posture, abdominal girth, and fatigue of muscles has long been proposed but without definite basis.
Prognosis
1. Most nonmalignant acute back pain is self-limited, but certain individuals are prone to repeated acute injury and chronic discomfort.
2. Most population studies show about 50% improvement in acute pain level by 1 month, continued slower improvement over the following 2 months, and persistent pain in those who have not improved by that time. Individual pain trajectories vary considerably, and having pain relapses during recovery is common.
3. The risk of recurrence of acute back pain within 3 months of an episode is about 25% and within a year is about 75%.
4. The prognosis of infectious, inflammatory, or malignant low back pain is determined by the nature and treatment responsiveness of the underlying process.
Diagnosis
1. Straight leg raising and derivative maneuvers and the motor, reflex, and sensory examination are most useful in detecting lumbar root compression as described further on.
2. Sharp percussion of the spine may disclose tumor infiltration or compression fracture of a vertebral body.
3. Facet loading maneuvers—worsening of pain by extension of the back and rotation to one side—can point to lumbar facet joints as a cause of back pain.
4. Imaging of the lumbar spine with x-ray, computed tomography (CT), or MRI is not required in cases that conform by history to musculoskeletal or acute mechanical low back pain.
5. Plain films of the lumbar spine have limited value but may demonstrate degenerative arthritis and may reveal metastatic disease to spinal bones. Views in flexion and extension are useful in detecting instability of lumbar segments as the source of back pain.
6. Degenerative changes of the joints and disc spaces on imaging studies are common with aging. Their presence does confirm that these changes are the cause of low back pain.
7. Pain that persists for more than 6 weeks and is not explained by preceding bouts of acute injury should have imaging to detect cancer, fracture, and osteomyelitis.
8. In cases of otherwise unexplained deep lumbar pain or flank pain, imaging of the retroperitoneal space, abdomen, and sometimes the pelvis, is advisable.
9. Erythrocyte sedimentation rate, C-reactive protein, blood cultures, and immunoelectrophoresis are useful to exclude infection, cancer, and myeloma in appropriate cases.
Treatment
1. Treatment for both acute and chronic low back pain combines nonpharmacologic and pharmacologic measures.
2. Patients with painful low back strain may be obliged to rest in bed or easy chair, but beyond symptomatic relief, there is no evidence that rest speeds improvement. The patient can determine the most comfortable position—lying with pillows under or between the knees or decubitus position may reduce pain.
3. Warmth to the back improves pain in many patients with acute low back pain. Gentle massage may help as well. There is better evidence for physical therapy with chronic low back pain compared to acute pain.
4. Nonsteroidal anti-inflammatory drugs improve musculoskeletal low back pain. Acetaminophen may help with conflicting evidence. Muscle relaxants such as cyclobenzaprine may help modestly. For chronic pain, there is evidence for duloxetine for small pain improvement. Other agents such as tricyclic antidepressants or gabapentinoids are used without significant evidence base.
5. Chiropractic adjustment may speed up the return to functional capacity after low back strain. Low-velocity distraction and ballottement administered by qualified physical therapists are also helpful. Compression fracture, cancer, and infection are reasons to avoid adjustments.
6. Instructions in proper biomechanics of sitting, lifting, bending, and carrying are appropriate for individuals with recurrent or postural low back pain. Weight support belts for workers may reduce injury.
7. Patients with chronic low back pain as with any chronic pain disorder should be screened for mood disorder that may be contributing to the pain syndrome.
8. Low back pain worse with back extension may be related to facet joint pain and can be diagnosed by medial branch blocks (diagnostic and therapeutic for facetogenic pain).
9. Back pain from bulging but nonruptured discs alone is not aided by surgery.
10. In the special circumstances of degenerative spondylolisthesis, pain may be improved by surgery with fusion, but cases must be selected with care. More harm than good is done by ill-considered surgery (see later sections).
SCIATICA
Background
1. Sciatica refers to sharp and aching pain that originates in the buttock or gluteal fold and radiates down the back or lateral aspect of the thigh. The term has been used for other nondescript back and leg pains but then loses its utility as a sign of nerve root compression.
2. Unlike the types of low back pain described in earlier sections, sciatica usually indicates L4, L5, or S1 nerve root compression.
3. Bilateral sciatica usually signifies severe degenerative spinal disease.
History
1. The patient describes pain beginning in or around the buttock on one side and radiating to the posterior or posterolateral thigh. When radiation below the knee or into the foot occurs, the diagnosis is more specific.
2. Most sciatica does not have acute precipitating events, but lifting, twisting, or back injury may precede the symptom. The combination of paraspinal lumbar pain followed in hours or days by sciatica is most characteristic of lumbar disc rupture.
3. The severity of sciatic pain varies, but at its extreme, it is very disabling and prevents either sitting, standing, or walking.
4. A few patients with sciatica have additional neurologic symptoms: numbness in the foot, foot drop, or weakness of ankle plantar flexion.
5. Chronic low back pain and limitation of lumbar motion when associated with sciatica suggest lumbar stenosis (see later section).
6. Bilateral sciatica with either leg weakness or urinary incontinence indicates compression of the cauda equina, an urgent condition.Related posts:
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