Vertebroplasty and Kyphoplasty

Vertebroplasty and kyphoplasty are minimally invasive procedures involving percutaneous injection of bone cement (typically PMMA) into vertebral compression fractures to provide pain relief and mechanical stabilization. While initially popular, landmark sham-controlled trials have called their efficacy into question.

Historical Development

Vertebroplasty was first performed by Galibert in France in 1987 for a painful cervical hemangioma. Kyphoplasty was developed in the 1990s with the addition of a balloon to create a cavity and potentially restore vertebral height. Rapid adoption occurred before rigorous evidence existed.

Current Controversy

The VERTOS II (2009) and subsequent trials showed no benefit over sham procedures, challenging routine use. However, some argue that appropriate patient selection and timing may identify those who benefit. Practice has shifted toward more conservative approaches.

Vertebral Anatomy

Relevant Structures:

• Vertebral body (anterior column)
• Posterior wall of vertebral body
• Pedicle (needle pathway)
• Basivertebral venous plexus (cement leakage pathway)
• Spinal canal and neural structures posteriorly

Vertebral Compression Fracture Pathophysiology

Mechanism:

• Axial loading on osteoporotic bone
• Anterior column failure (anterior wedging)
• Usually spares posterior wall and pedicles
• Pain from periosteal nerves, instability, inflammatory response

Risk Factors for VCF:

• Osteoporosis (primary)
• Corticosteroid use
• Metastatic disease
• Multiple myeloma
• Primary bone tumors

Cement Biomechanics

PMMA Properties:

• Exothermic polymerization (heat generation)
• Viscosity changes during injection
• Provides immediate stability
• No biological incorporation (remains foreign body)

Height Restoration (Kyphoplasty):

• Balloon creates cavity in cancellous bone
• May restore some vertebral height
• Height restoration may not correlate with clinical outcome
• Kyphosis correction usually modest

Patient Selection

Clinical Assessment

History:

• Mechanism (minimal trauma typical for osteoporotic)
• Duration of symptoms
• Pain character and location
• Functional limitation
• Red flags for malignancy or infection

Physical Examination:

• Midline tenderness over fracture level
• Neurological examination (rule out deficit)
• Sagittal alignment (kyphosis assessment)
• Other spinal tenderness (multiple levels?)

Contraindications

Absolute:

• Neurological deficit requiring decompression
• Active infection (vertebral or systemic)
• Uncorrectable coagulopathy
• Severe posterior wall destruction with canal compromise

Relative:

• Healed fracture with no edema
• Minimal symptoms
• Retropulsion of fragments
• More than 3 levels requiring treatment
• Young patient (consider other options)

Additional Investigations

Bone Density (DEXA):

• Confirms osteoporosis
• Baseline for treatment monitoring
• T-score guides systemic treatment

Laboratory:

• Rule out myeloma (SPEP, UPEP, light chains)
• Inflammatory markers if infection suspected
• Coagulation studies before procedure

Nuclear Medicine (Bone Scan):

• Alternative if MRI contraindicated
• Increased uptake = active fracture
• Less specific than MRI

Technical Pearls

Cement Viscosity:

• "Toothpaste" consistency preferred
• Too thin = extravasation risk
• Too thick = difficult injection

Fluoroscopy:

• Continuous monitoring during injection
• Lateral view for posterior wall
• AP view for midline and pedicle

Volume:

• Typically 2-5 mL per vertebra
• Avoid overfilling
• Quality over quantity

Postoperative Care

Same Day or Next Day Discharge:

• Mobilize when comfortable
• Analgesia as needed
• Resume activities as tolerated
• Follow-up in 4-6 weeks

Cement Extravasation

Other Complications

Pulmonary Cement Embolism:

• Rare but potentially fatal
• Cement migrates through venous system
• May be asymptomatic or cause cardiopulmonary compromise
• Prevention: Monitor viscosity, stop if venous filling seen
• Treatment: Supportive, anticoagulation, rarely surgical

Adjacent Level Fracture:

• Incidence 10-20% within 1-2 years
• Controversial if cement increases risk
• May be natural osteoporotic progression
• Risk factors: Osteoporosis severity, cement volume, kyphosis

Other Complications:

• Infection (rare, less than 1%)
• Pedicle fracture
• Rib fracture (thoracic levels)
• Hematoma
• Transient radiculopathy

Immediate Postprocedure

Recovery:

• Monitor for 2-4 hours
• Neurological assessment
• Pain assessment
• Mobilize when comfortable

Discharge:

• Same day or next day typical
• Return to normal activities as tolerated
• Analgesia as needed (often reduced)

Activity Guidelines

Osteoporosis Management - Critical

Essential Systemic Treatment:

• Calcium and Vitamin D supplementation
• Bisphosphonates or denosumab
• Consider anabolic agents (teriparatide) for severe cases
• Fall prevention strategies
• Lifestyle modifications

Follow-up:

• 4-6 weeks: Clinical assessment
• DEXA: Per osteoporosis guidelines
• Radiographs if new symptoms

Evidence Summary - The Controversy

VERTOS II (2009):

• Sham-controlled RCT
• 101 patients, vertebroplasty vs sham
• No significant difference at 1 month, 1 year
• Challenged routine use of vertebroplasty

VERTOS III (2018):

• Sham-controlled RCT for kyphoplasty
• Similar findings - no benefit over sham

VAPOUR Trial (2016):

• RCT of vertebroplasty for acute fractures (under 6 weeks)
• Showed benefit over sham at 14 days
• Suggests timing matters

FREE Trial (2009):

• Kyphoplasty vs conservative treatment
• Kyphoplasty superior at 1 month
• Difference diminished by 12 months
• Not sham-controlled

Interpretation

Arguments Against Augmentation:

• Sham-controlled trials show no benefit
• Placebo effect likely significant
• Complications from cement are real

Arguments For Selective Use:

• Acute fractures (under 6-8 weeks) may benefit
• Rapid pain relief (even if diminishes over time)
• VAPOUR and other trials suggest early intervention helps
• Patient selection may be key

Adjacent Level Fractures

Incidence: 10-20% at 1-2 years

Debate:

• Some argue cement increases risk
• Others argue it simply reflects osteoporotic progression
• Both augmented and non-augmented VCF patients get new fractures

Pathological (Neoplastic) VCF

Different Considerations:

• Palliative intent (pain relief, quality of life)
• May provide stability for radiation therapy
• Cement extravasation risk may be higher (tumor destruction)
• Consider in conjunction with radiation/systemic therapy

When to Consider Surgery Instead:

• Neurological deficit
• Significant canal compromise
• Need for tissue diagnosis
• Life expectancy warrants more definitive treatment

Multiple Level Fractures

Challenges:

• Each level adds procedural time and risk
• Cumulative cement load
• Prioritize most symptomatic levels
• Consider staged procedures

Timing Considerations

Acute (under 6 weeks):

• VAPOUR trial suggests possible benefit
• May offer faster pain relief
• Edema on MRI confirms acuity

Subacute (6 weeks to 3 months):

• Debatable benefit
• Conservative treatment often effective
• Consider if severe refractory pain

Chronic (more than 3 months):

• Little evidence for benefit
• No edema on MRI = healed
• Unlikely to respond to cement

Young Patients

Avoid if Possible:

• Traumatic VCF in young patients usually treated surgically
• Consider underlying bone pathology
• Long-term effects of cement unknown
• Reserve for exceptional circumstances

Management Pathway

Step 1: Diagnosis and Assessment

• Confirm painful VCF (history, examination)
• Imaging: X-ray then MRI (assess acuity, rule out tumor/infection)
• Assess for neurological deficit, posterior wall involvement

Step 2: Rule Out Contraindications

• Neurological deficit → Consider surgery
• Active infection → Treat infection
• Burst fracture with canal compromise → Surgery
• Coagulopathy → Correct before procedure

Step 3: Conservative Treatment (3-6 weeks)

• Analgesia, activity modification
• Osteoporosis treatment (essential)
• Physical therapy as tolerated
• Most patients improve

Step 4: Persistent Severe Pain

• Confirm MRI edema still present (acute fracture)
• Discuss evidence with patient (VERTOS controversy)
• Shared decision-making

Step 5: If Augmentation Chosen

• Vertebroplasty vs kyphoplasty (similar outcomes)
• Informed consent including extravasation risks
• Transpedicular approach, fluoroscopic guidance
• Continue osteoporosis management post-procedure

Current Practice in Australia

Practice in Australia has evolved following the VERTOS trials. There is now greater emphasis on conservative management and more rigorous patient selection. Procedures are still performed but with clear documentation of indications and informed consent discussion.

Both vertebroplasty and kyphoplasty are available, with the choice often based on surgeon preference and specific patient factors. Multi-disciplinary osteoporosis management is emphasized.

Medicolegal Considerations

Given the controversial evidence, thorough documentation is essential including clear indication (acute painful VCF failed conservative treatment), discussion of VERTOS trial evidence, informed consent covering the debate about efficacy, documentation of MRI findings (acute edema), and discussion of alternatives.

Ensure patients understand that the procedure remains controversial and that conservative treatment is a reasonable alternative.

Key Takeaways

1. VERTOS Trials Changed Practice: Sham-controlled trials (VERTOS II, III) showed no benefit of vertebroplasty or kyphoplasty over sham procedure at 1 year. This is a landmark finding and common exam topic.

2. Acute Fractures May Differ: The VAPOUR trial suggested benefit for very acute fractures (under 6 weeks). Timing may matter - MRI edema confirms acuity.

3. Cement Extravasation is Common: 10-20% of procedures have some extravasation, mostly asymptomatic. Serious complications (epidural compression, pulmonary embolism) are rare but can occur.

4. Contraindications are Critical: Neurological deficit requires decompression, not cement. Healed fractures without edema will not benefit.

5. Kyphoplasty vs Vertebroplasty: Kyphoplasty creates a cavity (lower extravasation, may restore height) but clinical outcomes are similar. Height restoration does not clearly correlate with pain relief.

6. Treat the Osteoporosis: Systemic osteoporosis management is more important than the augmentation procedure. All patients need calcium, vitamin D, and anti-resorptive therapy.

7. Shared Decision-Making: Given the controversial evidence, honest discussion with patients about the limited evidence is essential. Conservative treatment remains a reasonable alternative.