Orthopaedic Surgery - Spondylolisthesis

Basics

Spondylolisthesis is:

Abnormal translation of one vertebral body relative to the adjacent vertebra.

Most commonly, the upper vertebral body moves:

Anteriorly

relative to the vertebra below it.

Relationship to Spondylolysis

Spondylolisthesis may develop because of a defect in the:

Pars interarticularis

known as:

Spondylolysis

or because of failure or degeneration of other:

Posterior ligamentous and bony stabilizers.

Classification

Spondylolisthesis is classified according to:

Etiology

and

Severity of vertebral translation.

Major Types

The principal categories include:

Isthmic

Dysplastic or congenital

Degenerative

Traumatic

Pathologic

and

Iatrogenic spondylolisthesis.

Isthmic Spondylolisthesis

Isthmic spondylolisthesis results from a defect in the:

Pars interarticularis.

This defect most often develops as a:

Stress fracture

during childhood or adolescence.

Degenerative Spondylolisthesis

Degenerative spondylolisthesis occurs because of:

Disc degeneration

Facet-joint degeneration

and subsequent:

Segmental instability.

It most commonly affects:

L4–L5

in older adults.

Prevention

There is no proven strategy that reliably prevents development or progression of:

Spondylolisthesis.

Bracing

Long-term brace treatment has historically been proposed to limit progression, but because substantial progression is:

Uncommon

routine prolonged bracing for asymptomatic slips is generally:

Not recommended.

Bracing may nevertheless be used temporarily for:

Pain control

in selected symptomatic adolescents.

Epidemiology

Isthmic spondylolysis and spondylolisthesis generally begin during:

Childhood or adolescence.

The prevalence increases slightly during:

Adolescent growth.

Adult Prevalence

By adulthood, spondylolysis or related spondylolisthesis affects approximately:

5–6% of the population

in many historical series.

Age of Onset

Pars defects are:

Not present at birth

in typical isthmic disease.

They generally appear after children begin:

Walking and loading the spine.

The condition is rarely seen before approximately:

5–6 years of age.

Sex

Isthmic disease has historically been reported more often in:

Males.

However, females may demonstrate:

Greater slip progression

and may develop more substantial vertebral translation at a younger age.

Degenerative Disease

Degenerative spondylolisthesis predominantly affects:

Older adults

and is more common in:

Women.

Level

Isthmic spondylolysis occurs most commonly at:

L5

with translation of L5 over:

S1.

Degenerative spondylolisthesis occurs most frequently at:

L4–L5.

Risk Factors

Important risk factors include:

Positive family history

Repetitive lumbar hyperextension

High-impact adolescent sports

Generalized connective-tissue laxity

and selected:

Skeletal disorders.

Athletic Activities

Activities repeatedly loading the lumbar spine in:

Extension

may increase the risk of developing a pars stress injury.

Examples include:

Gymnastics

Football lineman activities

Diving

Weight lifting

and other sports involving repetitive:

Hyperextension and rotation.

Genetics

A positive family history increases the likelihood of:

Spondylolysis and spondylolisthesis.

Historical reports suggest approximately:

One-quarter of affected patients

may have a family history of the disorder.

Associated Genetic Disorders

The risk of vertebral translation may be increased in conditions associated with:

Bone weakness

or

Connective-tissue laxity.

Examples include:

Osteogenesis imperfecta

and some heritable:

Connective-tissue disorders.

Etiology

The underlying mechanism differs according to the:

Type of spondylolisthesis.

Isthmic Etiology

Isthmic disease usually begins as a:

Stress fracture through the pars interarticularis.

Repeated mechanical loading prevents normal healing and may produce:

Fibrous nonunion or pseudoarthrosis.

Development of Listhesis

A pars defect alone does not necessarily produce vertebral translation.

Progression to spondylolisthesis requires additional deformation or failure through:

The intervertebral disc

and surrounding:

Soft-tissue restraints.

Degenerative Etiology

Degenerative spondylolisthesis develops through progressive:

Disc degeneration

Facet arthrosis

and loss of:

Segmental stability.

Associated Conditions

Most patients are otherwise:

Neurologically and systemically normal.

However, increased risk may occur with:

Marfan syndrome

Neuromuscular disease

Athetoid cerebral palsy

and other disorders associated with:

Spinal instability or connective-tissue laxity.

Diagnosis

Diagnosis is based on:

History

Physical examination

and

Imaging.

It is important to determine whether the observed spondylolisthesis is actually responsible for the patient’s:

Symptoms.

Signs and Symptoms

Symptoms may begin:

Insidiously

or follow relatively minor:

Trauma or repetitive athletic loading.

Back Pain

Patients may complain of:

Low-back pain

sometimes extending into the:

Buttocks

or

Posterior thighs.

Radicular Pain

L5 nerve-root irritation may cause:

Sciatica

Numbness

or

Weakness

in an:

L5 distribution.

Gait Abnormality

Patients with more significant slips may develop:

Abnormal gait

or altered:

Pelvic and lumbar posture.

Posture

High-grade slips may produce compensatory:

Pelvic retroversion

and alterations in:

Lumbar lordosis.

Depending on the deformity, patients may appear either unusually:

Hyperlordotic

or relatively:

Hypolordotic.

Trauma History

Symptoms may appear after:

Acute trauma

or more commonly after repetitive:

Sports-related microtrauma.

Physical Examination

The examination should include assessment of:

Gait

Spinal alignment

Lumbar motion

Hamstring flexibility

and

Neurologic function.

Lumbar Extension

Pain is often increased by:

Lumbar hyperextension

particularly in patients with active:

Pars stress injury or spondylolysis.

Forward and Backward Bending

Assess:

Flexion

Extension

and

Rotation.

Restricted motion may reflect:

Pain

Hamstring tightness

or advanced deformity.

Hamstring Tightness

Patients with significant spondylolisthesis may develop marked:

Hamstring tightness.

This may limit:

Straight-leg raising

and

Forward flexion.

Limited Straight-Leg Raise

A limited straight-leg-raise test associated with marked hamstring tightness may be seen in:

High-grade spondylolisthesis

particularly in adolescents.

Neurologic Examination

A complete neurologic assessment should include:

Motor strength

Sensation

Reflexes

and evaluation for:

Radiculopathy.

L5 Radiculopathy

Severe slips may stretch or compress the:

L5 nerve root.

Possible findings include weakness of:

Ankle dorsiflexion

Great-toe extension

and

Hip abduction.

Cauda Equina Assessment

In patients with severe neurologic symptoms, assess for:

Saddle anesthesia

Urinary dysfunction

Bowel dysfunction

and progressive:

Lower-extremity weakness.

Laboratory and Electrodiagnostic Tests

Routine laboratory testing is generally:

Not required.

Electromyography

EMG and nerve-conduction studies may occasionally help evaluate:

L5 nerve-root dysfunction

when the neurologic diagnosis remains:

Uncertain.

Imaging

Plain Radiographs

Conventional radiographs are the initial study for diagnosing and grading:

Spondylolisthesis.

Lateral Radiograph

A standing:

Lateral lumbar radiograph

shows the degree of:

Vertebral translation.

For L5–S1 disease, a focused lateral view centered on:

L5–S1

can improve visualization.

AP Radiograph

An AP view helps evaluate:

Alignment

Spinal deformity

and associated:

Congenital abnormalities.

Oblique Views

Oblique radiographs historically have been used to visualize the:

Pars interarticularis.

The pars represents the:

Neck of the “Scotty dog.”

A pars defect may appear as a break through the:

Dog’s neck.

Because oblique views add radiation and may not always improve diagnosis, they are used more selectively in modern practice.

Flexion-Extension Radiographs

Dynamic views can assess:

Segmental motion

and

Instability.

They are particularly useful in:

Degenerative

or

Iatrogenic spondylolisthesis.

MRI

MRI is useful for identifying:

Early stress reaction

before a complete pars defect develops.

MRI Findings in Early Spondylolysis

MRI may show:

Bone marrow edema

or stress reaction around the:

Pars interarticularis.

Neural Compression

MRI is also useful for determining the degree of:

Nerve-root compression

Central canal stenosis

and

Foraminal stenosis.

Disc Assessment

MRI can evaluate the condition of adjacent discs, particularly the:

L4–L5 disc

when planning treatment for:

L5–S1 disease.

CT

CT provides excellent visualization of:

Cortical bone

and is highly useful for detecting:

Pars defects

Sclerosis

and

Chronic nonunion.

SPECT

Technetium bone scintigraphy with SPECT has historically been used to identify:

Metabolically active pars stress injuries

when radiographs are normal or equivocal.

MRI is now frequently preferred because it avoids:

Ionizing radiation.

Diagnostic Blocks

In selected difficult cases, injections around a pars defect or other suspected pain source may help determine whether the lesion is:

Symptomatic.

Discography is used much less commonly because of:

Limited specificity

and its invasive nature.

Classification by Etiology

Isthmic

Associated factors include:

Family history

Gymnastics

Football line play

and repetitive:

Lumbar hyperextension.

Dysplastic or Congenital

This form results from congenital abnormalities of the:

Lumbosacral junction

that predispose the vertebra to:

Progressive slip.

It may be associated with abnormalities such as:

Spina bifida occulta.

Pathologic

Pathologic spondylolisthesis may result from structural weakening caused by:

Tumor

Infection

or other destructive:

Bone disease.

Traumatic

Acute traumatic spondylolisthesis follows fracture or disruption of:

Posterior spinal elements

other than a chronic pars stress defect.

It may be associated with:

Neurologic injury.

Degenerative

Degenerative disease typically affects older adults, particularly during the:

Sixth and seventh decades.

It occurs most frequently at:

L4–L5.

Iatrogenic

Iatrogenic spondylolisthesis may follow removal of stabilizing posterior structures during:

Prior spinal surgery.

Meyerding Grading

Severity is commonly described by the percentage of:

Anterior vertebral translation.

Grade 0

No measurable slip

although a pars defect may still be present.

Grade I

Translation of:

0–25%.

Grade II

Translation of:

26–50%.

Grade III

Translation of:

51–75%.

Grade IV

Translation of:

76–100%.

Grade V

Complete displacement beyond the supporting vertebra is called:

Spondyloptosis.

Pathological Findings

The common lesion in isthmic disease is a defect through the:

Pars interarticularis.

Chronic Pars Defect

A longstanding defect may demonstrate:

Fibrous nonunion

Pseudoarthrosis

and

Reactive sclerosis.

Nerve Compression

Fibrous tissue at the pars defect or foraminal narrowing associated with translation may compress the:

L5 nerve root.

Differential Diagnosis

The presence of a pars defect or spondylolisthesis does not prove that it is the source of:

Pain.

Many patients have asymptomatic:

Radiographic abnormalities.

Important Alternatives

Other causes of low-back or leg pain include:

Lumbar disc herniation

Degenerative disc disease

Facet arthropathy

Spinal stenosis

Tumor

Infection

and other causes of:

Radiculopathy.

L4–L5 Disc Disease

A patient with L5–S1 isthmic spondylolisthesis may actually have symptoms from an:

L4–L5 disc herniation

or degeneration.

Clinical and imaging findings should therefore be carefully:

Correlated.

Treatment

Treatment depends on:

Age

Symptoms

Slip grade

Slip progression

Neurologic findings

and underlying:

Etiology.

Children and Adolescents

Most symptomatic low-grade slips can initially be treated:

Nonoperatively.

Activity Modification

Painful extension-based activities should be reduced until:

Symptoms resolve

and painless motion returns.

Bracing

A lumbar brace may be used for several months in selected adolescents with:

Symptomatic active pars lesions

or painful:

Low-grade spondylolisthesis.

Its purpose is mainly to:

Reduce pain and limit extension

rather than reliably reverse an established slip.

Nonoperative Outcomes

Historical series report good or excellent outcomes in up to approximately:

90% of appropriately selected young patients.

Observation

Once symptoms resolve, patients may be followed clinically.

Serial radiographs may be obtained every:

1–2 years until skeletal maturity

when there is concern for:

Slip progression.

Failure of Nonoperative Treatment

Surgery may be considered when symptoms persist despite approximately:

6–12 months of appropriate conservative management

or when the patient has a:

Symptomatic high-grade slip.

Adults

Adults with low-grade disease and symptoms consistent with mechanical back pain are often initially treated with:

Nonoperative measures.

Higher-Grade Adult Slips

More advanced symptomatic slips may require:

Fusion

and, when neural compression is present,

Nerve-root decompression.

Management depends on the specific pathology rather than grade alone.

Activity

Asymptomatic patients with low-grade stable spondylolisthesis generally do not require:

Routine activity restriction.

Symptomatic Patients

Activities should be reduced until the patient regains:

Painless lumbar motion

and adequate:

Core and hamstring function.

Physical Therapy

Physical therapy commonly emphasizes:

Hamstring stretching

Core stabilization

Abdominal strengthening

and control of excessive:

Lumbar extension.

Lumbar Posture

Historically, exercises aimed at reducing excessive:

Lumbar lordosis

have been used to decrease extension stress across the:

Pars.

Medication

Medication may include standard treatment for:

Mechanical low-back pain.

Options include:

Acetaminophen

NSAIDs

and, in selected short-term circumstances,

Muscle relaxants.

Surgery

Surgery is considered for:

Persistent disabling pain

Progressive neurologic deficit

High-grade slip

Progressive deformity

or failed:

Nonoperative treatment.

Direct Pars Repair

In selected young patients with:

Symptomatic pars defects

without substantial disc degeneration or high-grade translation, direct repair of the:

Pars interarticularis

may preserve:

Spinal motion.

Posterolateral Fusion

A traditional procedure for symptomatic L5–S1 spondylolisthesis is:

Posterolateral L5–S1 fusion.

Instrumented Fusion

Modern fusion commonly uses:

Pedicle-screw instrumentation

to improve:

Mechanical stability

and

Fusion rate.

Decompression

When significant L5 radiculopathy is present, the:

L5 nerve root

may require adequate:

Foraminal decompression.

Reduction

Whether a high-grade slip should be:

Reduced

or fused largely:

In situ

remains individualized.

Reduction may improve:

Alignment

but can place the:

L5 nerve roots

under substantial traction.

Anterior Column Support

Severe slips may occasionally require:

Interbody or anterior-column fusion

to improve stability and:

Fusion probability.

Levels of Fusion

The number of levels included depends on:

Slip severity

Lumbosacral alignment

Adjacent disc health

and

Patient age.

Follow-Up

Patients treated nonoperatively should be monitored for:

Pain

Neurologic symptoms

and

Progression of slip.

Skeletally Immature Patients

Children and adolescents with remaining growth may require periodic:

Standing lateral radiographs

until:

Skeletal maturity.

Postoperative Follow-Up

After fusion, follow-up evaluates:

Alignment

Neurologic status

Implant position

and development of:

Solid fusion.

Prognosis

Most patients with low-grade spondylolisthesis have a:

Favorable prognosis.

Low-Grade Slips in Children

Most symptomatic low-grade slips in children and adolescents respond to:

Nonoperative treatment

and do not result in long-term:

Disability.

Back Pain Risk

Spondylolisthesis may modestly increase the likelihood of:

Chronic low-back pain

but many patients remain:

Asymptomatic.

Slip Progression

Major progression is uncommon after:

Skeletal maturity

particularly in low-grade:

Isthmic slips.

Degenerative slips may progress with continued:

Disc and facet degeneration.

Complications

Lumbar Radiculopathy

L5 radiculopathy may occur because of:

Foraminal narrowing

Fibrous tissue

or progression of:

Vertebral translation.

Neurologic Injury With Reduction

One of the most important complications of surgical reduction is:

L5 nerve-root injury.

This may produce:

Pain

Sensory loss

or

Motor weakness.

Cauda Equina Syndrome

Very severe slips may rarely cause compression of the:

Cauda equina

resulting in:

Saddle anesthesia

Bowel dysfunction

Bladder dysfunction

and

Lower-extremity weakness.

This requires:

Urgent evaluation.

Pseudarthrosis

Spinal fusion may fail to achieve solid union, resulting in:

Pseudarthrosis.

This can lead to:

Persistent pain

Implant failure

or need for:

Revision surgery.

Adjacent-Segment Degeneration

Long-term fusion may increase mechanical loading at adjacent spinal levels and contribute to:

Degenerative changes.

Patient Monitoring

Monitoring should focus on:

Pain severity

Neurologic function

Gait

Hamstring tightness

Slip progression

and development of:

Radicular or cauda equina symptoms.

Key Principle

Spondylolisthesis is abnormal translation of one vertebra relative to another, most commonly caused by either a:

Pars interarticularis defect in isthmic disease

or

Disc and facet degeneration in degenerative disease.

The condition is graded according to the percentage of vertebral slip:

Grade I up to 25%, Grade II 26–50%, Grade III 51–75%, Grade IV 76–100%, and Grade V representing spondyloptosis.

Most low-grade slips, especially in children and adolescents, can be treated with:

Activity modification, physical therapy, analgesia, and selective bracing.

Surgery is reserved for:

Persistent disabling symptoms, progressive neurologic deficit, high-grade or progressive slips, or failed nonoperative treatment, with procedures ranging from:

Pars repair to decompression and instrumented spinal fusion.