Burst Fractures

A neurologically injured burst fracture raises the perennial question of high-dose methylprednisolone. The NASCIS II and III trials suggested a marginal motor benefit if a 24-48 hour high-dose methylprednisolone infusion was started within 8 hours of injury - but the effect was small, derived from post-hoc subgroup analysis, and came with a real increase in complications (wound infection, pneumonia, GI bleeding, hyperglycaemia, sepsis).

On that basis most contemporary guidance (AANS/CNS, and the spinal-trauma community broadly) no longer recommends routine high-dose steroids for acute SCI; some bodies (e.g. AOSpine) regard a 24-hour infusion within 8 hours as an option to be discussed, not a standard. Exam-safe answer: steroids are not a substitute for timely decompression and stabilisation, their routine use is not recommended, any use is an individualised time-limited decision weighed against significant complication risk, and they are contraindicated in penetrating injury and the high-infection-risk polytrauma patient.

The open posterior fusion above is not the only construct. For the neurologically intact but mechanically unstable burst (e.g. AO A4/B not needing decompression), two modern options are examinable:

• Percutaneous (minimally invasive) pedicle screw fixation - the same short-segment construct placed through small stab incisions under fluoroscopy/navigation, giving less blood loss, less muscle stripping and faster mobilisation, at the cost of no formal posterolateral fusion bed.
• Fixation without fusion ("internal bracing") - posterior instrumentation stabilises the fracture while the body heals, then the implants are removed (typically around 9-12 months) to restore segmental motion and reduce adjacent-segment stress. Attractive in younger patients with good bone and a healable fracture, it avoids fusion morbidity but requires a second (removal) operation and is unsuitable when the disc is destroyed (the segment will collapse once hardware is out).

The principle: match the invasiveness and the fusion/no-fusion decision to whether decompression is needed, the bone quality, the disc integrity and the patient's age - an MIS no-fusion construct can over-treat a brace-able injury and under-treat a high-LSC one.

Q: What defines a burst fracture and differentiates it from a compression fracture? A: Involvement of the posterior vertebral body wall (middle column) with retropulsion into the canal. Compression fractures only involve the anterior column.

Q: What are the three components of the McCormack Load-Sharing Classification? A: Comminution (1-3), fragment Apposition (1-3), and Kyphosis correction needed (1-3). Score 7+ predicts posterior-only failure.

Q: At what LSC score should anterior column reconstruction be considered? A: LSC 7 or more - short segment posterior-only constructs have a high failure rate at this threshold (36% broken screws in McCormack's original series).

Q: A patient has 50% canal compromise but is neurologically intact with intact PLC. Does this require surgery? A: No - canal compromise alone does not mandate surgery. It remodels spontaneously. TLICS would be 2 (non-operative).

Q: What is the most common type of burst fracture in the Denis classification? A: Type B (superior endplate) - accounts for 70% of burst fractures.

Q: When is ligamentotaxis most effective for reducing retropulsed fragments? A: When PLL is intact and surgery is performed within 72 hours. Beyond this, fragments become adherent.