A patient sustained C7-C8 incomplete myelopathy with dissociated sensory loss after a whiplash injury. Cervical radiograms showed no fracture or dislocation but separation of the C4-C5 and C5-C6 spinous processes and anterior tilting on C5 on C6 vertebral body only in the head-neck flexed position. Complete sensory and motor recovery occurred after neck immobilization. The patient's transient neurologic deficits were probably caused by vascular insufficiency of an anterior radicular artery at the C5-C6 intervertebral foramen.

The increasing use of more rigid internal fixation constructs for spinal fractures, especially in association with spinal cord injury, has led surgeons to combine sublaminar segmental wiring with Harrington instrumentation systems. Two clinical cases whose neurologic condition deteriorated postoperatively were shown to have sustained direct cord injury by the combination of Harrington compression rods with segmental sublaminar wiring. Myelographic and surgical evidence of hook protrusion into the spinal canal with direct cord injury is presented. Laboratory spine simulations duplicating the clinical situation did demonstrate that sublaminar wiring of the Harrington compression rod system caused the standard hooks to protrude dangerously into the spinal canal. Caution should be exercised not to combine Harrington compression rods with segmental sublaminar wiring.