Bisegmental posterior stabilisation of thoracolumbar fractures with polyaxial pedicle screws: Does additional balloon kyphoplasty retain vertebral height?

Abstract

We retrospectively evaluated single-level compression fractures (T12-L3) scheduled for a short-segment POS (posterior-only stabilization) using polyaxial screws. Patients averaged 55.7 years (range, 19-65). Patients received either POS or, concomitantly, BK (balloon kyphoplasty) of the fractured vertebrae as well. Primary endpoint was the radiological outcome at the last radiographic follow-up prior to implant removal. POS together with BK of the fractured vertebrae resulted in a significant improvement of the local kyphosis angle and vertebral body compression rates immediately post-OP. During the further course of FU, a considerable loss of correction was observed post-OP in both groups. (Local KA: pre-OP/ post-OP/ FU: 12.6±4.8/ 3.35±4.8/ 11.6±6.0; anterior vertebral body compression%: pre-OP/ post-OP/ FU: 71.94±12.3/ 94.78±19.95/ 78.17±14.74). VAS was significantly improved from 7.2±1.3 pre-OP to 2.7±1.3 (P<0.001) at FU. We found a significant restoration of the vertebral body height by BK. Nevertheless, follow-up revealed a noticeable loss of reduction. Given the fact that BK used together with polyaxial screws did not maintain intra-operative reduction, our data do not support this additional maneuver when used together with bi-segmental polyaxial pedicle screw fixation.

Effectiveness of the Endplate Reduction Technique Combined With Bone Grafting for the Treatment of Thoracolumbar Fractures by Using Posterior Short-Segment Fixation

“…9 Bone cement is also difficult to absorb within the vertebral body and prolonged retention within the vertebral body can have a detrimental effect on adjacent vertebrae and discs. 26,40 The risk of implant breakage was lower in the EPR group than in the IS group (0% vs. 9.2%, p = 0.04). In the analysis of this study, this was partly because the fracture was better repositioned and maintained in the EPR group and the fracture healed better, which effectively relieved the stresses on the implant; and partly because the 6-screw fixation in the IS group was more robust but had a greater concentration of stresses, whereas the 4-screw fixation in the EPR group retained some mobility above and below the fractured vertebral body, which stress concentrations are reduced.…”

“…Some studies demonstrated that the strength of the 4-screw fixation using a short posterior approach across the injured vertebral body was adequate compared to the 6-screw fixation method of IS group by repositioning the endplate and effectively filling the bone defect, consistent with the results of this study. [25][26][27] The EPR group and the IS group were compared in this study, focusing on the assessment of radiological indices. The result indicated that the EPR group had no significant advantage over the IS group in resetting the VWA, CA, and AVBH, whereas it maintained the resetting better with less postoperative correction loss.…”

“…27,28 In recent years, the importance of EPR has begun to attract the attention of orthopedic surgeons. 12,25,29 EPR is important, but indirect repositioning methods that rely solely on ligamentous distraction are not effective in restoring the collapse of the central endplate injury, 22,25,26 which directly affects the change in the vertebral space and increases the risk of recurrent kyphosis and chronic low back pain. 30 Endplate prying was employed in the EPR group, prying the endplate and disc as a whole to directly pry and reposition the endplate injury, by prying from a thinner pedicle opener (4 mm), thus increasing the flexibility of the prying and facilitating adjustment of the prying direction and positioning.…”