Anterior Kostuik-Harrington distraction systems for the treatment of kyphotic deformities.

Based on the biomechanical principles of anterior distractive forces combined with instrumentation to decrease sagittal bending moments, an anterior system using a modification of Harrington instrumentation has been developed for the correction of kyphotic deformities. It has been used in the treatment of acute burst fractures in 100 cases, posttraumatic kyphosis in 45 cases, Scheuermann's kyphosis in 36 cases, rigid round backs in three cases, acute rigid kyphosis (congenital) in four cases, postlaminectomy in 21 cases, flat back syndrome in 56 cases, kyphosis secondary to tumor in ten cases, and kyphosis secondary to osteoporosis with fracture in four cases. A total of 279 cases have been treated with anterior instrumentation. Complications include breakage of 35 screws and four rods. There have been no early or late vascular or neurologic sequelae related to instrumentation. The biomechanical basis for the treatment of kyphotic deformities includes an anterior distractive force to resist compressive loads and, where possible, segmental fixation to decrease sagittal bending moments combined with bone grafts far from the neutral axis. This system provides these benefits with minimal risk and morbidity.