# Vertebroplasty and Kyphoplasty

## Introduction

**Vertebroplasty** and **kyphoplasty** are minimally invasive percutaneous procedures that involve injection of polymethylmethacrylate (PMMA) bone cement into fractured vertebral bodies. These procedures provide rapid pain relief and structural stabilization for patients with painful vertebral compression fractures (VCFs) refractory to conservative management.

## Indications

**Osteoporotic vertebral compression fractures** with persistent pain despite 2-6 weeks of conservative therapy (analgesics, bracing, activity modification). **Pathologic fractures** from metastatic disease or multiple myeloma. **Painful vertebral hemangiomas** with aggressive features. **Osteonecrosis** (Kummell disease) with intravertebral vacuum cleft. Fractures from **T5 to L5** (cervical and upper thoracic are relative contraindications).

## Contraindications

**Asymptomatic fractures** or pain adequately controlled with conservative measures. **Active osteomyelitis** or discitis at the target level. **Uncorrectable coagulopathy**. **Retropulsed fracture fragments** with significant spinal canal compromise. **Burst fractures** with posterior wall disruption (relative; may be performed with caution). Fracture involving the **posterior elements** primarily.

## Preprocedural Evaluation

### Imaging

**MRI with STIR sequence**: identifies acute/subacute fractures by marrow edema; critical for determining which levels to treat. **CT**: evaluates posterior wall integrity, pedicle anatomy, and fracture morphology. **Bone scan**: alternative when MRI is contraindicated; hot uptake indicates active fracture.

### Clinical Assessment

Correlate imaging findings with the patient's **point tenderness** and pain distribution. Assess for **neurological deficits** that may indicate spinal cord or nerve root compression. Review coagulation parameters; hold anticoagulation per institutional protocol.

![MRI STIR sequence showing marrow edema in an acute L1 compression fracture compared to chronic T12 fracture without edema](verte-mri-stir.png)

## Vertebroplasty Technique

### Patient Positioning and Access

**Prone** position on a radiolucent table with fluoroscopic guidance (biplane preferred). General anesthesia or moderate sedation with local anesthesia. **Transpedicular approach**: most common; 11-13 gauge trocar needle advanced through the pedicle into the anterior third of the vertebral body. **Parapedicular (extrapedicular) approach**: used when pedicles are too small or fractured. AP fluoroscopy confirms the needle tip does not cross the medial pedicle wall until the needle is at the posterior vertebral body wall on lateral view.

### Cement Injection

**PMMA bone cement** is mixed and allowed to reach a toothpaste-like consistency before injection. Inject under **continuous lateral fluoroscopy** to monitor cement flow in real time. Typical volume: **2-4 mL per vertebral body** for thoracic; **4-8 mL** for lumbar. Stop injection immediately if cement approaches the **posterior vertebral body wall**, epidural space, or venous channels.

## Kyphoplasty Technique

### Balloon Tamp Placement

Access is similar to vertebroplasty via transpedicular approach. After trocar placement, a **balloon tamp (inflatable bone tamp)** is advanced into the vertebral body. Balloon is inflated under fluoroscopic guidance to create a cavity and restore vertebral body height. Inflation pressure typically 150-300 psi; monitored with a pressure syringe.

### Vertebroplasty vs. Kyphoplasty Comparison

| Feature | Vertebroplasty | Kyphoplasty |
|---------|---------------|-------------|
| Balloon tamp | No | Yes (creates cavity) |
| Height restoration | Minimal | Average 2-3 mm gain |
| Kyphosis correction | No | Possible |
| Cement extravasation rate | 19-41% | 7-9% |
| Injection pressure | Higher | Lower (contained cavity) |
| Cost | Lower | Higher (balloon device) |
| Pain relief | Equivalent | Equivalent |
| Procedure time | Shorter | Longer |

### Advantages Over Vertebroplasty

Creates a **contained cavity** that allows lower-pressure cement injection. Potential for **height restoration** and **kyphosis correction** (average 2-3 mm height gain). Lower rate of **cement extravasation** compared to vertebroplasty (7-9% vs. 19-41%).

![Lateral fluoroscopic view showing balloon tamp inflation within a compressed vertebral body during kyphoplasty](kyphoplasty-balloon.png)

## Outcomes

**Pain relief**: 80-95% of patients report significant pain improvement within 24-72 hours. Improvement in **functional status** and **quality of life** measures. Durable pain relief maintained in most patients at 1-2 year follow-up. Controversy exists regarding superiority over sham procedures based on RCTs (INVEST, FREE trials).

## Complications

### Cement Extravasation

Most common complication; reported in up to 40% of vertebroplasty cases (usually asymptomatic). **Epidural leakage**: risk of spinal cord or nerve root compression; may require urgent surgical decompression. **Foraminal leakage**: can cause radiculopathy. **Venous extravasation**: may cause pulmonary cement embolism (usually asymptomatic; rarely fatal). **Disc leakage**: may predispose adjacent-level fractures.

### Other Complications

**Adjacent-level fractures**: occur in 12-20% within the first year; debated whether due to altered biomechanics or natural disease progression. **Infection**: rare (less than 1%); strict sterile technique essential. **Rib fractures** from prone positioning in osteoporotic patients. **Pedicle fracture**: from aggressive needle placement.

![CT showing cement distribution within a vertebral body after vertebroplasty with small amount of asymptomatic venous extravasation](cement-distribution-ct.png)

## Special Considerations

### Metastatic Disease

Kyphoplasty or vertebroplasty provides effective palliation for painful pathologic fractures. Can be combined with **radiation therapy** for durable tumor control. Cement fills the lytic defect and provides structural support, reducing fracture risk.

### Multiple-Level Treatment

Up to 3-4 levels can be treated in a single session. Higher volumes increase the risk of hemodynamic effects from PMMA monomer toxicity (hypotension, cardiac depression). Monitor vital signs closely during multi-level procedures.

## Key Clinical Pearls

MRI with STIR or short-tau inversion recovery sequences is essential for identifying acute fractures that will benefit from treatment; do not treat chronic fractures without marrow edema. Cement injection must be performed under continuous lateral fluoroscopy; AP views alone are insufficient to detect posterior cement leakage toward the spinal canal. Kyphoplasty is preferred over vertebroplasty when height restoration is desired and when treating fractures with posterior wall compromise, as the lower-pressure cavity fill reduces extravasation risk. Adjacent-level fractures are the most common long-term complication; patients should receive concurrent osteoporosis treatment.

## References

1. Defined Defined Defined Defined Buchbinder R, Johnston RV, Rischin KJ, et al. Percutaneous Vertebroplasty for Osteoporotic Vertebral Compression Fracture. Cochrane Database Syst Rev. 2018;4:CD006349.
2. Defined Defined Defined Defined Defined Defined Wardlaw D, Cummings SR, Van Meirhaeghe J, et al. Efficacy and Safety of Balloon Kyphoplasty Compared with Non-Surgical Care for Vertebral Compression Fracture (FREE). Lancet. 2009;373(9668):1016-1024.
3. Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined Defined