Orthopaedic Surgery - Back Pain

Basics

Low back pain (LBP) is one of the most common musculoskeletal complaints and is a major cause of disability. It accounts for a substantial number of years lived with disability and is responsible for a very large amount of lost work productivity.

An estimated 149 million workdays per year are lost because of low back pain, and approximately 70–80% of adults experience a significant episode of back pain at some point during their lives.

Back pain may involve the bones, joints, ligaments, discs, or muscles of the spine. It occurs most frequently in middle-aged adults but may also affect children and adolescents.

Classification

Back pain can be broadly classified as traumatic or atraumatic.

Pathologic pain may originate directly from the spine, including spondylogenic or neurogenic causes, or may arise from structures outside the spine, including visceral, vascular, or psychogenic sources.

Because low back pain is a symptom rather than a single disease, careful clinical assessment is necessary to determine its underlying cause.

Synonyms

Common terms include backache and low back pain (LBP).

Epidemiology

Low back pain is extremely common in adults.

It is less common in children, and significant back pain in a child should prompt careful investigation.

Children or adolescents with scoliosis may report mild discomfort, but severe or persistent pain should raise concern for conditions such as infection, tumor, fracture, or another structural abnormality.

Age Considerations

The prevalence of chronic low back pain increases with age and is highest during approximately the fifth and sixth decades of life.

Most surgical procedures performed for low back pain occur in patients between approximately 35 and 55 years of age.

Sex Distribution

Back pain has historically been reported more frequently in males, partly because of greater exposure to manual labor, motor vehicle trauma, and industrial accidents.

However, low back pain affects both sexes and is common across the general population.

Incidence

Approximately 25% of adults in the United States report experiencing low back pain over a given period.

The burden of disease is substantial because symptoms may interfere with work, exercise, mobility, sleep, and activities of daily living.

Prevalence

The point prevalence of chronic low back pain among adults aged approximately 20–69 years has been reported at around 13%.

The likelihood of chronic symptoms rises with age.

Risk Factors

Important risk factors include obesity, cigarette smoking, manual labor, and traumatic accidents.

Repeated heavy lifting, prolonged mechanical loading, poor physical conditioning, and certain occupational exposures may also contribute.

Genetics

There is no single established genetic predisposition that explains most cases of nonspecific low back pain.

However, inherited factors may contribute indirectly to certain disorders, such as degenerative disc disease or inflammatory spondyloarthritis.

Pathophysiology

There is no single pathologic process responsible for all forms of back pain.

The mechanism depends on the underlying disorder and may involve mechanical strain, disc degeneration, nerve compression, inflammation, fracture, infection, neoplasm, or referred pain from other structures.

Etiology

Traumatic Causes

Traumatic causes include vertebral fractures or microfractures, fracture-dislocations, intervertebral disc herniation, and ligamentous injuries.

Fractures and major structural injuries usually produce sudden and often severe pain following trauma.

Atraumatic Causes

Atraumatic causes include degenerative disc disease, degenerative spinal stenosis, inflammatory arthritis, osteoporosis, spondylolysis, spondylolisthesis, infection, and neoplasms.

Tumors may be primary bone lesions or metastatic disease.

Associated Conditions

Low back pain may occur in association with ankylosing spondylitis, rheumatoid arthritis, sciatica, and cauda equina syndrome.

Neurologic symptoms accompanying back pain require particular attention because they may indicate nerve root or spinal canal compromise.

Diagnosis

Signs and Symptoms

Common symptoms include low back pain, stiffness, and numbness.

Patients may also experience radiating pain into the buttocks or lower extremities when nerve roots are involved.

Neurologic Signs

Potential examination findings include paravertebral muscle spasm, motor weakness, loss of deep tendon reflexes, sensory loss, clonus, and a positive Babinski sign.

The presence of upper motor neuron findings or significant neurologic deficits should prompt further investigation.

History

A detailed history is essential because routine diagnostic studies are often unnecessary in uncomplicated low back pain.

The clinician should determine the onset, location, severity, duration, and character of pain, together with aggravating and relieving factors.

A history of trauma, systemic illness, malignancy, infection risk, osteoporosis, or neurologic symptoms is particularly important.

Pain Mapping

Rather than relying only on verbal descriptions, asking the patient to identify or map the exact distribution of pain can improve localization.

The pattern may help distinguish localized mechanical pain from radicular, referred, or systemic causes.

Red Flag History

Important concerning features include night pain, unexplained weight loss, fever, recent serious trauma, history of malignancy, immunosuppression, intravenous drug use, progressive neurologic deficit, or bowel and bladder dysfunction.

These findings may indicate serious structural disease and require urgent investigation.

Physical Examination

Examination begins with inspection of the spine and overall posture.

The clinician should assess for asymmetry of the ribs, flanks, pelvis, or shoulders, and should observe the normal sagittal spinal curves.

Deformities such as scoliosis, excessive kyphosis, or abnormal lumbar lordosis should be documented.

Range of Motion

Lumbar motion should be assessed in flexion, extension, lateral bending, and rotation.

Pain suddenly reproduced during a specific movement may suggest a mechanical abnormality.

Restriction of motion may occur because of pain, muscle spasm, degenerative disease, inflammation, or structural deformity.

Palpation

The lumbar spine and surrounding muscles should be palpated for tenderness.

Paravertebral muscle spasm may be present in acute mechanical pain.

Percussion tenderness over the spine may raise concern for fracture, infection, or other osseous pathology.

Neurologic Examination

The neurologic examination is a crucial component of assessment.

It should include motor strength, sensory testing, deep tendon reflexes, and gait evaluation.

The distribution of weakness or sensory loss may help identify the involved nerve root.

Motor Testing

Major muscle groups of the lower extremities should be examined systematically.

Weakness may indicate nerve root compression, spinal cord involvement, severe pain inhibition, or another neurologic disorder.

Reflexes

Deep tendon reflexes should be assessed and compared bilaterally.

Abnormal or absent reflexes may indicate nerve root involvement, whereas hyperreflexia, clonus, or a positive Babinski response may suggest spinal cord pathology.

Gait Examination

The patient’s gait should be observed for antalgia, weakness, foot drop, imbalance, or other neurologic abnormalities.

Difficulty with heel or toe walking may provide additional information regarding specific nerve root or muscle dysfunction.

Laboratory Tests

There are no routine laboratory tests required for uncomplicated mechanical low back pain.

Investigations should be guided by clinical suspicion.

Evaluation for Infection

When infection is suspected, a complete blood count and erythrocyte sedimentation rate (ESR) may be obtained.

Inflammatory markers are commonly elevated in spinal infection, with ESR often being particularly useful.

C-reactive protein may also assist in assessing inflammatory activity.

Evaluation for Multiple Myeloma

In older patients, particularly those over approximately 50 years of age with unexplained persistent back pain, laboratory investigations may be used to screen for disorders such as multiple myeloma when clinically indicated.

HLA-B27 Testing

In younger patients with marked spinal stiffness and symptoms suggestive of inflammatory back pain, testing for HLA-B27 may support evaluation for ankylosing spondylitis.

It should not be used as a stand-alone diagnostic test.

Imaging

Plain Radiographs

Routine radiographs are not necessary for every first episode of uncomplicated low back pain, particularly when symptoms follow a minor mechanical event such as lifting and there are no concerning findings.

Imaging should be considered when history or examination suggests a significant structural abnormality.

Indications for Imaging

Radiographs may be appropriate when there is suspicion of fracture, ankylosing spondylitis, severe deformity, malignancy, infection, or another important structural disorder.

The decision to image should be based on clinical findings rather than pain alone.

CT

Computed tomography is particularly useful for evaluating bony abnormalities.

It can provide detailed assessment of fractures, pars defects, osteoid osteoma, and other osseous lesions.

CT is also helpful when complex anatomy must be defined before surgery.

MRI

MRI provides excellent visualization of bone marrow, discs, ligaments, neural structures, and surrounding soft tissues.

It is particularly useful for detecting disc herniation, spinal stenosis, infection, metastatic disease, marrow abnormalities, and nerve compression.

MRI is generally the preferred advanced imaging modality when neurologic symptoms or serious spinal pathology are suspected.

Bone Scintigraphy

Technetium bone scanning can help detect areas of increased skeletal activity.

It may be useful for identifying early bone infection, stress injury, occult fracture, or metastatic lesions.

Its use has decreased in many situations because MRI often provides more detailed anatomic information.

Differential Diagnosis in Adults

Traumatic Causes

Important traumatic causes include herniated disc, compression fracture, fracture-dislocation, and traumatic spondylolysis.

A clear traumatic history increases suspicion for these conditions.

Atraumatic Causes in Adults

Atraumatic causes include degenerative disc disease, spinal stenosis, inflammatory arthritis, spondylolysis, spondylolisthesis, ligamentous or muscular strain, and neoplasm.

Malignant causes include metastatic bone disease and multiple myeloma.

Differential Diagnosis in Children

Back pain in children deserves careful attention because serious causes are relatively more important.

Traumatic causes include fracture and disc herniation.

Atraumatic causes include scoliosis, disc-space infection, vertebral osteomyelitis, and tumors.

Persistent severe pain should not automatically be attributed to muscular strain.

Treatment

General Measures

Most patients with uncomplicated low back pain can be managed nonoperatively.

Treatment may include short-term rest, appropriate analgesia, NSAIDs when indicated, activity modification, and physical therapy.

The overall aim is to restore mobility and prevent deconditioning.

Bed Rest

Prolonged bed rest is generally not beneficial.

In patients with severe acute spasm or pain, a very short period of rest—often no more than 2–3 days—may be reasonable.

During the first several days, activity may be temporarily restricted, but progressive mobilization should begin as symptoms improve.

Early Mobilization

If no serious structural abnormality is identified, patients should gradually resume activity.

Early mobilization helps prevent muscle weakness, stiffness, loss of cardiovascular fitness, and prolonged disability.

Physical Therapy

Physical therapy and structured exercise can improve back strength, flexibility, range of motion, posture, and general fitness.

Therapy should be tailored to the underlying diagnosis and the patient’s functional limitations.

Exercise Programs

Traditional exercise approaches include the Williams flexion program and McKenzie extension-based exercises.

No single exercise method is appropriate for every patient.

Programs emphasizing coordination, stabilization, strength, and resistance training are particularly useful in chronic low back pain.

Core and Stabilization Training

Exercises targeting the abdominal, paraspinal, pelvic, and hip muscles can improve spinal stability.

Motor-control and stabilization programs may reduce recurrent symptoms and improve function in patients with chronic mechanical low back pain.

Activity Modification

Patients should be educated regarding safe lifting techniques, posture, gradual return to activity, and strategies for preventing recurrent injury.

Temporary modification of work or sporting activity may be required during painful episodes.

Work-Hardening Programs

Patients injured at work may benefit from a structured work-hardening program.

These programs progressively reproduce occupational tasks in a controlled setting and help restore strength, endurance, and confidence before return to full duty.

Passive Therapies

Massage, acupuncture, electrical stimulation, and other passive modalities may provide temporary symptom relief.

However, they generally provide less durable benefit than active exercise and strengthening programs.

They should therefore be considered adjuncts rather than the primary long-term treatment.

Medication

NSAIDs

Nonsteroidal anti-inflammatory drugs are commonly used for short-term symptomatic relief.

They may reduce pain and inflammation sufficiently to allow earlier mobilization and participation in rehabilitation.

Treatment should be individualized according to gastrointestinal, renal, cardiovascular, and other patient-specific risks.

Duration of Medication

NSAIDs may be prescribed for several weeks when necessary, but treatment should be reassessed regularly.

Once symptoms improve, medication can usually be reduced or discontinued.

Muscle Relaxants

Muscle relaxants have a limited role in routine management.

They may be useful for short-term relief in patients with severe muscle spasm, especially during an acute episode.

They are generally not recommended for prolonged use.

Treatment of Spinal Infection

When infection is present, treatment requires appropriate antimicrobial therapy and management of the infected spinal segment.

Intravenous antibiotics are commonly required initially.

Inflammatory markers such as ESR and CRP may be followed to assess response to treatment.

Surgical Management

Only a minority of patients with low back pain require surgery.

Approximately 1–5% may ultimately become candidates for operative treatment, depending on the underlying pathology.

Surgery is generally reserved for clearly defined structural problems that fail to respond to appropriate conservative care or threaten neurologic function.

Surgical Principles

The principal surgical goals include decompression of compressed nerve roots or the spinal cord, stabilization of an unstable spine, and correction of significant deformity.

The exact procedure depends on the diagnosis.

Decompression

Nerve root or spinal cord compression may require surgical decompression.

Examples include significant disc herniation, spinal stenosis, tumor, infection, or traumatic compression associated with neurologic deficits.

Spinal Fusion

Fusion may be used when instability is present or when decompression would otherwise leave the spine unstable.

It can also be considered for selected cases of deformity, spondylolisthesis, or severe degenerative disease.

Fusion solely for nonspecific low back pain is relatively uncommon.

Deformity Correction

Patients with significant spinal deformities such as scoliosis or spondylolisthesis may require realignment combined with fusion.

Correction is generally considered when deformity is progressive, symptomatic, unstable, or neurologically compromising.

Instrumentation

Modern spinal fusion may use a variety of fixation systems.

Examples include pedicle screws, rods, plates, and interbody devices.

Instrumentation provides mechanical stability and increases the likelihood of obtaining a solid fusion.

Lumbar Disc Arthroplasty

Lumbar disc replacement has been developed as an alternative to fusion for selected patients with persistent discogenic low back pain.

The objective is to remove the painful disc while preserving motion at the involved spinal level.

Short-term outcomes have been encouraging in appropriately selected patients.

Limitations of Disc Arthroplasty

Longer-term studies have demonstrated that prosthetic disc motion may gradually decrease over time.

Because of concerns regarding durability, patient selection, adjacent-segment effects, and revision surgery, lumbar disc arthroplasty remains controversial in some settings.

Follow-Up

Patients with uncomplicated low back pain should be reviewed according to symptom severity and functional limitation.

Follow-up at approximately 4–6-week intervals may be appropriate until substantial improvement occurs.

Persistent or worsening symptoms should prompt reconsideration of the diagnosis.

Prognosis

The prognosis is generally good in patients without major structural abnormalities.

Many episodes improve with activity modification, appropriate medication, exercise, and rehabilitation.

However, recurrent or chronic symptoms are common in some patients.

Prognosis After Fusion

Patients who undergo major spinal fusion can often return to many routine activities.

However, heavy manual work and repeated high-load activities may remain difficult because spinal motion is reduced and adjacent segments experience greater mechanical demand.

Complications

Potential complications of spinal disease and its treatment include infection, neurologic injury, surgical failure, pseudarthrosis, loss of fixation, and persistent unexplained pain.

Complication risk varies according to the underlying disorder and surgical procedure.

Pseudarthrosis

Pseudarthrosis refers to failure of a planned spinal fusion to unite.

It may result in persistent pain, hardware failure, deformity, or instability and may occasionally require revision surgery.

Cauda Equina Syndrome

Cauda equina syndrome is a neurologic emergency caused by severe compression of the cauda equina nerve roots.

It may result from a large disc herniation, tumor, infection, fracture, or other space-occupying lesion.

Signs of Cauda Equina Syndrome

Concerning findings include progressive bilateral leg weakness, saddle anesthesia, urinary retention or incontinence, bowel dysfunction, and severe neurologic loss.

Untreated compression can result in permanent paralysis and irreversible loss of bladder and bowel function.

Urgent imaging and surgical evaluation are required.

Patient Monitoring

Patients should demonstrate gradual improvement with rest, activity modification, appropriate medication, and rehabilitation.

Range of motion, strength, gait, neurologic function, and ability to perform daily activities should be monitored.

If pain fails to improve as expected or new neurologic or systemic symptoms develop, a significant structural or systemic cause should be reconsidered.