[Adult spondylolisthesis treated with the combination of angled and pushing-pulling pedicle screws]

Altogether 28 patients with degenerative (22 cases), isthmic (4 cases), and post-traumatic (2 cases) spondylolisthesis were treated with a reduction fixation system using both angled and pushing-pulling pedicle screws. Preoperatively, the percentages of the sliprage were < or = 25% in 15 cases, < or = 50% in 11, and < or = 75% in 2 cases. All patients had low-back pain and/or leg pain. Postoperatively, 28 cases obtained a nearly anatomical reduction. The average rate of correction was 98%. There is a significant difference (P < 0.01) compared with preoperation. After reduction, all patients had only two segmental rigid fixations with posterolateral bone grafting or postero-inter-body fusion. 27 cases had satisfactory pain relief postoperatively. No patient deteriorated neurologically with surgery. All patients were followed up for a minimum of 8 months ranging from 8 to 28 months (average 19). At the end of follow-up, in 26 patients correction remained unchanged with X-ray demonstrating radiographic evidence of fusion. Neither pseudarthroses nor significant complications occurred. The new system is a safe and effective pedicular fixation system, it has a three-dimensional correction force that allows for reduction of the spondilolisthesis and fixation of only two segments. It also gives more rigid fixation to maintain the reduction and increase the fusion rate. The new system gives satisfactory results over conventional hook and sub-lamina wire and other segmental spinal pedicle screw instrumentation systems.