1
Indications & Contraindications
When kyphoplasty is preferred over vertebroplasty
Indications
- Osteoporotic VCF with >15% height loss — balloon inflation can restore height before cementing; more height gain than vertebroplasty alone
- Fractures where cement containment is desired — cavity created by balloon reduces free cement flow through cancellous bone (lower leak risk than vertebroplasty)
- Acute fractures with burst pattern and intact posterior wall — controlled balloon inflation can reduce fracture; posterior wall must be intact to prevent retropulsed fragment worsening
- Kyphotic deformity — kyphoplasty provides modest kyphosis correction; preferred when sagittal balance restoration is a goal
- All indications for vertebroplasty also apply — osteoporotic, malignant, and traumatic VCFs with pain refractory to conservative management
Contraindications
- Absolute: Posterior wall disruption with retropulsed fragment causing neurologic deficit (surgery preferred) · Active infection · Uncorrectable coagulopathy · PMMA allergy
- Relative: Vertebra plana (>75% height loss) — balloon may not be deployable; consider SpineJack · Spinal instability requiring surgical fixation · Pregnancy
- Note: Burst fractures with posterior wall compromise — balloon inflation may worsen retropulsion. CT mandatory pre-procedure to assess posterior wall. If any doubt: vertebroplasty or SpineJack preferred over balloon
Kyphoplasty vs. Vertebroplasty — Key Differences
- Height restoration: Balloon inflation before cement provides active fracture reduction; vertebroplasty relies on cement pressure alone — minimal height gain
- Cement containment: Balloon creates a defined cavity; high-viscosity cement fills the cavity — lower leak risk compared to vertebroplasty (direct injection into cancellous bone)
- Cost: Kyphoplasty is more expensive (balloon system ~$1,500–3,000 per level vs. ~$200–400 for vertebroplasty)
- Anesthesia: General anesthesia used at many centers for kyphoplasty; vertebroplasty often MAC/local
- Evidence: FREE trial (Wardlaw et al, Lancet 2009) demonstrated superior outcomes for kyphoplasty vs. conservative management. Adjusted survival rate higher for kyphoplasty vs. vertebroplasty in retrospective Medicare data (Edidin et al)
2
Pre-Procedure Checklist
Imaging, labs, equipment planning
MRI spine with STIR sequence. Bone marrow edema (STIR hyperintensity) confirms active fracture. Grade compression on Genant scale: Grade 1 (20–25% height loss), Grade 2 (25–40%), Grade 3 (>40%). Kyphoplasty most beneficial for Grade 2–3 fractures with height loss amenable to restoration.
CT spine — posterior wall assessment is critical. Must confirm posterior wall integrity before balloon inflation. Any retropulsed fragment or cortical disruption of the posterior wall alters the plan: kyphoplasty may worsen canal compromise if balloon inflated blindly. Consider vertebroplasty or SpineJack instead.
Confirm level-appropriate balloon sizing. Kyphoplasty systems (e.g., Kyphon by Medtronic) come in specific balloon sizes. Review level anatomy and degree of collapse to select appropriate balloon volume. Upper thoracic: smaller volumes; lumbar: larger.
Labs. INR ≤1.5, platelets ≥50K (SIR Category 2). CBC, BMP. Type and screen not routinely required.
Anesthesia plan. MAC with monitored sedation preferred. General anesthesia commonly used at surgery-based centers or for complex multi-level procedures. Patient must tolerate prone positioning for procedure duration (typically 45–90 minutes).
Consent — specific kyphoplasty risks. Discuss: cement leak (lower risk than vertebroplasty but still present), failure to restore height (height gain not guaranteed — compliant balloon in very hard bone may not fully inflate), neurologic injury, adjacent fracture, pulmonary cement embolism.
Curved balloon kyphoplasty (AVAflex) planning. If using curved balloon system: single unipedicular approach possible — curved nitinol stylet traverses to contralateral hemivertebra. Confirm availability of AVAflex balloon and accessories if planned.
3
Relevant Anatomy
Access planning, balloon workspace, posterior wall
Access Approach
- Standard: Bilateral transpedicular — 8–10G Jamshidi/working cannula bilaterally, each to posterior one-third of vertebral body
- Extrapedicular: Used when pedicle too narrow (<4–5 mm), typically above T8
- Unipedicular (curved balloon): Single right pedicle entry — curved nitinol stylet advanced to traverse midline into contralateral hemivertebra, creating bilateral cavity from single access point
- Level range: T4–L5 (same as vertebroplasty); cervical spine kyphoplasty rare
The Posterior Wall — Critical Landmark
- Posterior cortex separates the vertebral body from the spinal canal and posterior elements
- Any fracture line or fragment involving the posterior wall is a warning sign — forced balloon inflation could displace bone into the canal
- On lateral fluoroscopy: confirm balloon tip does not contact or cross the posterior vertebral cortex during inflation
- Balloon inflation should be monitored in real time — stop at any resistance suggesting posterior wall proximity
Balloon Workspace
- Target position: Balloon placed in the central/anterior trabecular bone, posterior to the anterior cortex, anterior to the posterior wall
- Balloon inflation compacts trabecular bone radially and cranio-caudally, reducing the fracture and creating a defined cavity
- Cavity volume correlates with expected cement volume — do not overfill the cavity with cement
- In areas of dense or sclerotic bone (old fractures, post-radiation), the balloon may not fully inflate — partial restoration still beneficial
4
Technique
Default RadCall approach · share your own below
Supplies
Biplanar fluoroscopy (C-arm)
8–10G Jamshidi needle / working cannula (bilateral)
Kyphoplasty balloon system (Kyphon or equivalent)
Balloon inflator (manometer syringe)
PMMA bone cement (high-viscosity formulation)
1 mL Luer-lock syringes (cement delivery)
ChloraPrep
Sterile drapes
1% lidocaine
18G spinal needle (marking)
Mallet
Standard Bilateral Kyphoplasty Steps
1
Position & level localization
Patient prone on radiolucent table. Biplanar fluoroscopy configured. Confirm correct vertebral level with marking needle. Count ribs/levels on AP fluoroscopy. Check lateral for fracture morphology and degree of collapse. Prep and drape widely.
2
Bilateral pedicle entry
Local anesthesia (1% lidocaine) to skin, subcutaneous tissue, and periosteum. Make bilateral stab incisions. Advance 8–10G Jamshidi/working cannula through both pedicles using "owl eye" technique on AP fluoroscopy. Confirm position on both AP (midline of pedicle) and lateral (within pedicle, not crossing posterior wall). Advance cannula to posterior one-third of vertebral body.
▶ Bilateral pedicular access — working cannulae placed
Bilateral pedicular access: trocars positioned with tips at posterior vertebral body — confirm medial wall integrity before advancing to vertebral body.
3
Create working channel
Remove trocar from working cannula. Insert hand-drill or drill bit to create a channel in trabecular bone for balloon insertion. Advance to desired depth — typically to junction of posterior and middle thirds of vertebral body. Do not breach the anterior cortex.
▶ Drill creating working channel
Working channel creation: drill advanced to anterior one-third of vertebral body — lateral view confirms trajectory; stay posterior to anterior cortex.
4
Insert balloons bilaterally
Insert balloon tamps (one per side) through the working cannulae. Advance under lateral fluoroscopy until balloon markers are centered in the vertebral body. Confirm both balloons are in satisfactory position on AP and lateral views before inflation.
5
Balloon inflation — height restoration
Inflate both balloons simultaneously using manometer inflator syringes under continuous lateral fluoroscopy. Inflate slowly with 0.5 mL increments. STOP if: resistance plateaus without further height gain, balloon contacts posterior cortex on lateral view, or end-plate breakthrough occurs. Monitor inflation pressure — do not exceed manufacturer pressure limits. Goal: achieve near-normal height or maximum achievable height restoration.
▶ Bilateral balloon inflation — height restoration
Bilateral balloon inflation: sequential or simultaneous inflation to restore vertebral height — stop at posterior cortex contact, pressure >220 psi, or full volume.
6
Balloon deflation & removal
Once target height or pressure reached: fully deflate balloons using the inflator syringe (aspirate back to negative pressure). Remove deflated balloons from working cannulae. The cavity created by balloon inflation is now ready for cement. Do NOT delay cement injection — cavity can partially collapse if time is excessive.
7
Cement injection into cavity
Mix PMMA to high-viscosity (paste consistency) — this is important for kyphoplasty as the cavity holds more viscous cement, reducing extravasation risk. Inject under continuous fluoroscopy via 1 mL Luer-lock syringes. Fill cavity from anterior to posterior. STOP at any sign of posterior or foraminal leak. The cavity guides cement placement — less free flow into cancellous bone compared to vertebroplasty.
▶ Post-cement fill — completion fluoroscopy
Post-cement injection: AP and lateral views confirm intracavitary fill without epidural, foraminal, or vascular extravasation — stop injection if any leakage detected.
8
Needle removal & completion
After cement sets (1–2 min), rotate cannulae and remove with gentle traction. Apply pressure. Post-procedure lateral fluoroscopy to confirm cement distribution and vertebral height. Post-procedure CT of treated level recommended. Upright weight-bearing X-ray at follow-up visit to assess maintained height restoration.
Curved Balloon Kyphoplasty (AVAflex System)
A
Single unipedicular access
10G needle advanced through a single pedicle (typically right) to center of vertebral body on lateral fluoroscopy. Standard transpedicular approach for entry.
B
AVAflex nitinol stylet insertion
Coaxially insert the curved AVAflex nitinol stylet and introducer sheath through the 10G cannula. Advance horizontally across the midline into the contralateral hemivertebra. Confirm on AP fluoroscopy that stylet tip is in the contralateral half. This allows bilateral vertebral body coverage via a single pedicle access.
C
Balloon deployment & inflation
Remove stylet, leaving introducer sheath in place. Advance AVAflex balloon through the introducer. Retract introducer to expose balloon within the vertebral body. Inflate balloon to create cavity — it expands in the contralateral region given its curved trajectory. Monitor on AP and lateral fluoroscopy during inflation.
D
Curved needle cement delivery
Deflate and remove balloon and introducer. Insert curved nitinol AVAflex needle through the 10G cannula. Inject high-viscosity Vertaplex HV bone cement under fluoroscopy. Curved needle enables targeted cement placement into the cavity across midline. Remove needle and cannula once cement is set.
Sign in to view and create community cards
5
Troubleshooting
Problem
Balloon does not inflate / height not restored
Likely cause: Balloon in dense/sclerotic bone, old fracture with extensive callus, or chronic deformity where trabeculae have remodeled — no reducible fracture cleft remaining.
Next step: Attempt to advance balloon tip into the fracture cleft on lateral fluoroscopy. Try sequential inflation in small increments with increased force. If still no movement: partial inflation may be achievable. Partial height gain with good cavity formation is still clinically beneficial — pain relief does not require complete height restoration. Document outcome and adjust patient expectations.
Problem
Cement leak despite cavity — posterior extravasation
Likely cause: Posterior cortical disruption not identified pre-procedure, cement viscosity too low, or overfilling the cavity.
Next step: Stop injection immediately. Wait for cement to polymerize and self-seal at the leak site (1–2 min). Reassess on lateral fluoroscopy. For kyphoplasty, the cavity should contain most cement — leak suggests cortical breach. Abandon injection on that side if leak continues. Post-procedure CT mandatory to characterize extent.
Problem
Balloon rupture during inflation
Likely cause: Balloon contacted a sharp bony cortical edge, exceeded maximum inflation volume, or defective balloon.
Next step: Remove ruptured balloon fragments via working cannula (use fluoroscopy to confirm complete removal). Assess whether adequate cavity was created before rupture. If sufficient cavity present: proceed with cement injection. If not: replace with new balloon, or proceed with direct cement injection (converting to vertebroplasty technique). Most balloon remnants are radiopaque and can be confirmed removed on fluoroscopy.
Problem
End-plate breakthrough during inflation
Likely cause: Excessive inflation pressure or balloon positioned too cranially/caudally — contacts weakened end plate.
Next step: Stop inflation immediately. Deflate balloon. Reposition to a more central location and reattempt at lower pressure. Minor end-plate breakthrough may result in intradiscal cement leakage during cement injection — monitor carefully and stop if intradiscal filling seen.
6
Complications
Cement Extravasation (Lower Rate Than Vertebroplasty)
- Epidural: Cord/cauda equina compression — emergent surgical decompression if symptomatic neurologic deficit
- Foraminal: Radiculopathy; usually self-limited
- Intradiscal: End-plate breach leads to intradiscal injection; accelerates disc degeneration
- Venous / PE: Asymptomatic cement PE reported on CT in up to 5%; symptomatic PE rare
- Overall leak rate: Lower than vertebroplasty due to cavity containment — but not zero
Kyphoplasty-Specific Complications
- Failed height restoration: Chronic fractures, sclerotic bone — clinically acceptable if pain relief achieved
- Balloon rupture: Rare; usually manageable (retrieve fragments, proceed)
- End-plate disruption: Balloon inflation may breach end plate; monitor for intradiscal cement
- Adjacent vertebral fracture: As with vertebroplasty — stiffened cemented segment alters biomechanics
- Significant adverse events: 1.0–1.5% in large series (epidural cement requiring decompression, hematoma, osteomyelitis)
Emergent Escalation Triggers
- New neurologic deficit post-procedure → emergent spine surgery consult + CT spine
- Hypoxia / chest pain post-procedure → CT chest angiography (cement PE)
- Severe unremitting pain escalation → CT spine (epidural collection)
7
Post-Procedure Care
Recovery & Monitoring
- Recover supine 1–2 hours; neurologic exam before discharge
- Ambulate day of procedure when sedation cleared
- Anecdotal pattern: pain relief immediate post-procedure, returns within 24 hours (muscle spasm/inflammation), then resolves over 10–14 days
- Most patients discharged same day (ambulatory procedure) or next morning if admitted
- Post-procedure pain score documentation at 24 hours
Imaging & Follow-up
- Post-procedure CT of treated level to document cement distribution and confirm no canal encroachment
- Upright weight-bearing lateral X-ray at 4–6 week follow-up to assess maintained height restoration (balloon deflation after cement sets ensures durable height)
- Resume anticoagulation: 24 hours post-procedure
- Osteoporosis management referral — bisphosphonates, denosumab, or teriparatide
- Physical therapy for core strengthening and fall prevention
- Counsel on adjacent fracture risk; return to ED for new acute back pain or neurologic symptoms
8
Critical Pearls
✦
Inflate slowly with frequent fluoroscopy pauses: Rapid balloon inflation risks cortical breach or end-plate disruption. Inflate in 0.5 mL increments, pause on lateral fluoroscopy after each increment to check balloon position relative to posterior wall and end plates.
✦
High-viscosity cement is mandatory for kyphoplasty: The cavity created by the balloon should be filled with high-viscosity PMMA — this cement does not flow freely through trabecular bone and stays within the cavity. Low-viscosity cement in a kyphoplasty cavity negates the leak protection advantage over vertebroplasty.
✦
Deflate fully before cement injection: Partial balloon deflation leaves residual volume in the cavity — reducing space for cement. Aspirate to full negative pressure. Remove balloon quickly after deflation to prevent cavity collapse before cement is injected.
✦
Pain relief does not require height restoration: Multiple studies confirm that patients without significant height restoration still benefit from excellent pain relief after kyphoplasty. Do not attempt dangerous over-inflation to achieve more height — accept partial restoration if bone is resistant.
✦
Curved balloon (AVAflex) advantage: Single pedicle access saves time, reduces second access risk, and enables contralateral cavity creation from a unilateral approach. The curved nitinol stylet allows the balloon to traverse midline — covering the entire vertebral body from one entry point.
✦
Posterior wall assessment is non-negotiable: Always review CT pre-procedure for posterior wall integrity. Balloon inflation in a burst fracture with retropulsed fragment can push bone into the spinal canal. If in doubt: use vertebroplasty or SpineJack, which do not rely on balloon inflation for fracture reduction.
!
Cavity partially collapses if cement delay is excessive: After balloon deflation, the trabecular bone cavity may partially spring back. Inject cement promptly — do not take extended breaks between balloon removal and cement injection. Having cement already mixed at the correct viscosity before balloon deflation avoids this issue.
9
Related Resources
References, comparison table, related procedures
Vertebral Augmentation Comparison
| Feature | Vertebroplasty | Balloon Kyphoplasty | SpineJack |
|---|---|---|---|
| Mechanism | Direct cement injection | Balloon inflation creates cavity, then cement | Titanium implant expands craniocaudally, then cement |
| Height restoration | Minimal | Moderate (balloon inflation before cement) | Superior — up to 40% height gain; durable |
| Cement leak risk | Higher | Lower (contained cavity) | Low (implant contains cement) |
| Sedation | MAC / Local | MAC / General | General / MAC |
| Cost | Lowest | Moderate | Highest |
| Implant remains | No | No (balloon removed) | Yes (titanium implant permanent) |
| Best for | VCF without significant height loss; malignant fractures | Fractures with >15% height loss; intact posterior wall; when cavity containment desired | Acute fractures with significant height loss; young patients; durable restoration |
Primary Reference
Prologo JD, Ray CE Jr., eds. Advanced Pain Management in Interventional Radiology: A Case-Based Approach. Thieme; 2024. DOI: 10.1055/b000000387
Chapters 17 (Marshall — Osteoporotic Fracture II: Kyphoplasty) and 19 (McGraw & McGraw — Osteoporotic Fracture IV: Curved Balloon Kyphoplasty)
Additional references: FREE trial — Wardlaw et al, Lancet 2009 · Edidin et al, JBMR 2011 (mortality analysis) · ACR Appropriateness Criteria: VCF Management · SIR Consensus Guidelines for Periprocedural Management · AVAflex FDA approval 2017