Traction may enhance the imaging of spine injuries with plane radiographs: implications for the laboratory versus the clinic

Objective. In some of our work to quantify injury we had been unsuccessful in quantifying confirmed bony damage with conventional X-ray positioning. This motivated the current study to evaluate whether external loading would enhance radiologic imaging and interpretation of spinal injuries. It was hypothesized that traction loads would enhance injury manifestation on planar radiographic images. Design. Test–retest of fractured specimens both unloaded and loaded followed by dissection. Methods. Fresh, and previously frozen, cervical spines of pigs (80 kg) were set in potting fixtures and subjected to various types of loads until failure occurred. An aluminum fixture frame was fabricated to clamp the vertebrae over the X-ray film, and apply calibrated traction loads. Injuries were evaluated during dissection and compared to radiographic film evidence. Three examples are demonstrated in this technical note. Results. The application of 45–112 N (10–25 lbs) of traction load enabled the visibility of some injuries on film while it also enhanced imaging of others. Conclusions. Two major implications of this work when fractures are suspected are: Scientists using cadaveric material should consider the need to load spines in modest traction during positioning (112 N proved adequate in this study of porcine cervical spines) to enhance fracture imaging; we all need reminding that negative radiographs do not rule out massive fracture.