ABSTRACT
Thoracolumbar fractures are relatively common injuries. Numerous classification systems have been developed to characterize these fractures and their prognostic and therapeutic implications. Recent emphasis on short, rigid fixation has influenced surgical management. Most compression and stable burst fractures should be treated nonsurgically. Neurologically intact patients with unstable burst fractures that have >25 degrees of kyphosis, >50% loss of vertebral height, or >40% canal compromise often can be treated with short, rigid posterior fusions. Patients with unstable burst fractures and neurologic deficits require direct or indirect decompression. Posterior stabilization can be effective with Chance fractures and flexion-distraction injuries that have marked kyphosis, and in translational or shear injuries. Advances in understanding both biomechanics and types of fixation have influenced the development of reliable systems that can effectively stabilize these fractures and permit early mobilization.
Subject(s)
Fracture Fixation, Internal/instrumentation , Internal Fixators , Lumbar Vertebrae/injuries , Spinal Fractures/diagnosis , Spinal Fractures/surgery , Thoracic Vertebrae/injuries , Equipment Design , Equipment Safety , Female , Follow-Up Studies , Fracture Fixation, Internal/methods , Fracture Fixation, Internal/rehabilitation , Fracture Healing/physiology , Humans , Injury Severity Score , Male , Postoperative Care/methods , Recovery of Function , Risk Assessment , Spinal Fusion/instrumentation , Spinal Fusion/methods , Treatment OutcomeABSTRACT
BACKGROUND: We tested the hypothesis that a pedicle screw construct's height is an important factor in strengthening a screw-rod system. METHODS: Six corpectomy constructs were made, each using two ultra-high-molecular-weight polyethylene blocks, 6.5-mm pedicle screws, and two 6.35-mm rods. Pedicle screws were placed at +10-, +5-, 0-, and -5-mm depths in relation to the dorsal surface of the corpectomy model. Nondestructive testing was performed in flexion/extension and in torsion. RESULTS: For all modes tested, the screw-rod constructs continued to increase in stiffness as the height of the construct was lowered, and this was statistically significant at all heights tested (P < 0.001). The stiffness increased 232% when comparing flexion at +10 and -5 mm and increased 231% in extension from +10 to -5 mm. The torsional stiffness increased 171% when comparing +10 and -5 mm. CONCLUSIONS: Thus, lower-profile instrumentation systems should be used to take advantage of this by decreasing the size and bulkiness of the implants while increasing the strength of the construct.
