Balloon Kyphoplasty

The indication in one line. Balloon kyphoplasty is for a painful vertebral compression fracture with mechanical axial pain that correlates to the fractured level, where the fracture is subacute (typically less than 3 months) and shows bone-marrow oedema on MRI (STIR or T2 fat-suppressed sequences), and where conservative management — analgesia, bracing and physiotherapy for at least 4–6 weeks — has failed. Patient selection is the operation. The single strongest predictor of a good result is MRI bone-marrow oedema: a hypointense fracture line on T1 with bright STIR signal. Chronic fractures without oedema respond poorly (pain relief falls below 50 percent) and are a relative contraindication. Oedema is the gatekeeper — confirm it before offering the procedure. Absolute indications. A painful osteoporotic or pathological compression fracture with mechanical pain correlating to the level; a subacute fracture (less than 3 months) with bone-marrow oedema on MRI; failure of 4–6 weeks of conservative care (analgesia, bracing, physiotherapy); or a pathological fracture (myeloma, lymphoma, metastasis) with mechanical pain and limited life expectancy, where stabilisation improves quality of life. Relative indications. Progressive kyphosis with sagittal imbalance and secondary pain; multiple contiguous fractures where staged augmentation may prevent further collapse; and severe osteoporosis in whom prolonged bracing is poorly tolerated. Absolute contraindications. Active spinal infection or osteomyelitis at the target level; a neurological deficit attributable to the fracture (cord or cauda equina compression needing decompression); a burst fracture with significant retropulsion and canal compromise; and coagulopathy that cannot be corrected. Relative contraindications. A chronic fracture without oedema on MRI; greater than 50 percent vertebral height loss with severe endplate fragmentation (technical difficulty); and allergy to PMMA cement components.

Special situations.

• Pathological (tumour) fractures are excellent candidates when the goal is palliation: take a biopsy at the time of cannulation if the diagnosis is uncertain, expect to use smaller cement volumes, and add posterior stabilisation if there is instability or neurological compromise. Leakage consequences may be greater when tumour has eroded the posterior wall.
• Multiple contiguous levels are best staged — two levels per session — to limit cement load and operative time; plan caudal to cranial and reassess alignment after each stage.

Consent specifically for cement leakage (5–10 percent), neurological injury (less than 1 percent), pulmonary cement embolism (3–5 percent, mostly asymptomatic), adjacent-level fracture (10–20 percent at 1 year), infection (less than 1 percent), and the possibility of incomplete pain relief. Counsel that the procedure treats the fracture, not the underlying osteoporosis, which must be managed medically. Setup. Prone on a radiolucent table with chest and pelvic bolsters allowing free abdominal excursion (this lowers epidural venous pressure and bleeding), the spine in slight extension to help endplate reduction. High-quality biplanar fluoroscopy is mandatory — obtain true AP and lateral projections before skin preparation. Single-dose cefazolin at induction (vancomycin if penicillin-allergic); consider vancomycin powder in the wound for high-risk patients. General anaesthesia or conscious sedation per patient tolerance and fracture acuity.

The goal is to stabilise the fractured vertebra and relieve mechanical pain by creating a contained cavity inside the vertebral body with an inflatable bone tamp, then filling that cavity with high-viscosity PMMA cement at low pressure — achieving partial height restoration and kyphosis correction with a lower leakage rate than vertebroplasty. The whole procedure is percutaneous, through a bilateral transpedicular corridor, under continuous biplanar fluoroscopy. Why the transpedicular corridor is safe. The pedicle connects the posterior elements to the vertebral body. Advancing a needle down the pedicle's long axis keeps the instrument away from the exiting nerve root (which lies in the foramen just inferior to the pedicle) and the thecal sac and cord (which lie immediately medial to the medial pedicle wall). The posterior vertebral wall is the critical depth landmark — on lateral fluoroscopy the cannula tip must reach, but not breach, the posterior wall before entering the body. Cement can escape along the basivertebral and segmental veins (draining to the azygos system and the vena cava, causing pulmonary embolism) or through fractured endplates into the disc — which is why real-time imaging during injection is non-negotiable.

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Implants. The only implant is PMMA bone cement — typically 3–6 mL per level. No metallic hardware is used; the cement interdigitates with trabecular bone and gives immediate stabilisation by mechanical interlock once cured.

Immediate recovery. Mobilise as tolerated within 2–4 hours; no bracing is required. Analgesia with paracetamol, NSAIDs (if renal function allows) and a short course of weak opioid if needed. Most patients report a substantial reduction in their pre-operative pain within 24 hours. Standing radiographs at 4–6 weeks assess alignment and screen for adjacent fractures. Return to function.

• Light activities — immediately
• Driving — when comfortable, usually 3–7 days
• Heavy lifting — avoid for 6 weeks
• Sedentary work — within 1 week; manual work — 4–6 weeks Treat the disease, not just the fracture. Every patient needs a formal osteoporosis assessment initiated or optimised: a DEXA scan if not recent, calcium and vitamin D supplementation, antiresorptive or anabolic therapy per guidelines and fracture risk, and a fall-prevention programme. The augmentation stabilises one fracture; without medical therapy the next one follows.

Critical danger structures and exam traps

How kyphoplasty differs from vertebroplasty. Both deliver PMMA cement into a painful fractured vertebra for rapid pain relief. Balloon kyphoplasty first creates a contained cavity with the inflatable bone tamp before injection; this permits use of higher-viscosity cement at lower pressure and aims for partial height restoration and kyphosis correction. Vertebroplasty injects cement directly, without prior cavity creation. Landmark evidence. The FREE trial (Wardlaw, 2009) showed kyphoplasty superior to non-surgical care for pain and function at one month, with benefit sustained to 12 months and cement leakage in 9.5 percent with no neurological sequelae. VERTOS II (Klazen, 2010) showed vertebroplasty accelerates pain relief over conservative care. Head-to-head comparisons (Liu, 2010) show equivalent pain scores but modestly greater height restoration and kyphosis correction with kyphoplasty, at the cost of slightly longer operative time. Cement leakage is lower with kyphoplasty but not eliminated; adjacent-fracture rates are comparable between the two techniques. The KAST study and the Taylor meta-analysis confirm durable pain reduction to 24 months with rare major neurological complications.