Cervical Lateral Mass Fracture-Separation (Floating Lateral Mass)

A floating lateral mass fracture is defined by a fracture through both the lamina and the pedicle on one side, which separates the lateral mass from the vertebra and disconnects the superior and inferior articular processes - the facet joints above and below. Because the lateral mass is the bony link between consecutive facets, isolating it removes the posterolateral column's continuity and leaves the segment highly unstable, prone to rotation, kyphosis and facet subluxation (the lateral mass may rotate into a horizontal orientation). These are high-energy injuries, often with nerve root involvement and associated cervical injuries. CT defines the pattern, and because the lateral mass/pedicle lie next to the transverse foramen - and fracture-dislocation/subluxation patterns carry the highest risk - CTA should screen for vertebral artery (BCVI) injury.

• Assess fully. Document neurology (the exiting nerve root is at risk), assess alignment and the rest of the cervical spine, and CTA to screen for vertebral artery injury.
• Operative stabilisation is commonly required for this unstable injury - anterior, posterior or combined fusion. In reported series complications clustered in the posterior (hardware failure) and combined (respiratory) groups, with fewest in the anterior approach - so weigh injury pattern, alignment and associated injuries when choosing.
• Non-operative management (rigid immobilisation) is satisfactory for appropriately selected FLM fractures - in a reported cohort no carefully selected non-operative patient needed later surgery for subluxation.
• Individualise. Base the decision on stability, alignment, neurology and the whole injury picture rather than treating every FLM the same way.