gms | German Medical Science

Objective: Stabilization of osteoporotic vertebral fractures (type A3 acc. to AO) comprises a major challenge. Balloon-kyphoplasty does not address the posterior wall fragment and thus cannot restore axial stability. Classic-type posterior instrumentation tends to fail due to implant loosening. We therefore prefer combined vertebral stabilization by means of cement-augmented bi-level posterior instrumentation and single-level kyphoplasty.

Methods: Inclusion criteria for this prospective trial: A3-fractures of Th11-L5; integrity of adjacent discs (MRI); t-score ≤–2.5 (DEXA). Initial reduction and cement-augmentation performed by percutaneous Balloon-kyphoplasty (Medtronic) using PMMA-cement. Final reduction achieved by short-segment instrumentation of the adjacent vertebrae with PMMA screw-augmentation. Both conventional open (USS II; Synthes) and percutaneous (Sextant; Medtronic) techniques were applied for instrumentation. Data acquired: subjective pain rating (Visual Analogue Scale-VAS); bisegmental endplate-angle (plain X-rays). Patients were subject to full weight-bearing on day 1. Follow-up was performed on day 1; week 6; and months 3, 6, and 12.

Results: 52 patients with 208 augmented pedicle screws were included. Average patient age 74 (60 to 92). Average t-score -2.7. (–3.1 to –2.5). Leakage of cement in 41/208 pedicle screws. Direction of leakage was anterior/lateral for 40, epidural for 1 case. 3/52 cases with extrusion of cement during the kyphoplasty procedures. All 52 patients with marked pain-relief as expressed on the VAS. Average correction of endplate-angle 8.7°. During follow-up, no significant loss of correction with the exception of 2/52 patients in which there was cut-out of the cement-augmented cranial pairs of screws. Except those 2/52 cases, no case of implant loosening or cut-out of pedicle screws.

Conclusions: Combined cement-augmented instrumentation and kyphoplasty is efficient for stabilization of osteoporotic burst fractures. The typical shortcomings of conventional instrumentation (implant loosening; cut-out of screws) can be avoided. With the fixator providing sufficient axial stability for the posterior spinal wall, this technique allows for far anterior placement of the cement during kyphoplasty, thus adding to its safetyness. It can be performed percutaneously, additionally fitting elderly patients' needs. However, verification of disc-integrity is necessary, as this technique does not address the disc space.