Interpeduncular segmental fixation.

Attempts at segmental correction and fixation of the vertebral column usually result in biomechanical instability, defined as an alteration of any two of the longitudinal mechanical columns. This leads to a system that involves all three columns to restore stability to the spine. The use of specially-designed interpeduncular screws bilaterally and segmentally permits firm attachment of each vertebra through the pedicle and into the vertebral body, thus covering all three biomechanical columns. By attaching coupling screw drivers to each set of transpedicular screws, lordosis, kyphosis, and rotation can be corrected segmentally within the tolerance of disc elasticity. The correction of lateral deviation is accomplished in a segmental manner. As a preliminary report, 20 cases are presented between the ages of 15 and 55 years with a variety of spine pathology. All were treated with interpeduncular screw fixation (ISF) and arthrodesis. The average follow-up period is 15 months, so no conclusion of the rate of pseudoarthrosis can be made. The correction of pathology is 80% with balance and maintenance of physiologic saggital curves. There have been no complications in this group of patients.