Comparison of posterior fixation alone and supplementation with posterolateral fusion in thoracolumbar burst fractures

Abstract

Objective: We compared the radiological and clinical outcomes between patients who underwent posterior fixation alone and supplemented with fusion following the onset of thoracolumbar burst fractures. In addition, we also evaluated the necessity of posterolateral fusion for patients treated with posterior pedicle screw fixation.

Methods: From January 2007 to December 2009, 46 consecutive patients with thoracolumbar burst fracture were included in this study. On the basis of posterolateral fusion, we divided our patients into the non-fusion group and the fusion group. The radiological assessment was performed according to the Cobb's method, and results were obtained at immediately, 3, 6, 12 months after surgery. The clinical outcomes were evaluated using the modified Mcnab criteria at the final follow-up.

Results: The demographic data and the mean follow-up period were similar between the two groups. Patients of both groups achieved satisfactory clinical outcomes. The mean loss of kyphosis correction showed that patients of both groups experienced loss of correction with no respect to whether they underwent the posterolateral fusion. There was no significant difference in the degree of loss of correction at any time points of the follow-up between the two groups. In addition, we also compared the effect of fixed levels (i.e., short versus long segment) on loss of correction between the two groups and there was no significant difference. There were no major complications postoperatively and during follow-up period.

Conclusion: We suggest that posterolateral fusion may be unnecessary for patients with thoracolumbar burst fractures who underwent posterior pedicle screw fixation.

Keywords: Loss of kyphosis correction; Posterior pedicle screw fixation; Posterolateral fusion; Thoracolumbar burst fracture.

Fig. 1

A 48-year-old female was sustained an injury due to a motor vehicle. She was diagnosed with burst fracture of L1 and underwent a posterior short segment screw fixation including the index level (that is, the level of the burst fracture). A : The preoperative lateral view and CT scan show 17.9° kyphotic angle and 51% canal encroachment, respectively. B : The immediate postoperative lateral view shows that kyphotic angle was decreased to 13.6°. C : At a 1-year follow-up, the lateral view shows 18.1° kyphotic angle.

Fig. 2

A 42-year-old male fell backwards from height of 3 meters. He was diagnosed with burst fracture of L2 and underwent total laminectomy with posterior short segment screw fixation involving the index level. Instrumentations were supplemented with posterolateral fusion. A : The preoperative lateral view and CT scan show 10.1° kyphotic angle and 62% canal encroachment, respectively. B : The immediate postoperative lateral view shows 12.3° lordotic angle and AP view reveals that bone graft materials were placed in the transverse process of fixed segments. C : At a 1-year follow-up, the lateral view shows 6.2° lordotic angle and the AP view demonstrates that bone grafts were partially absorbed (progression of bone fusion).

Fig. 3

Changes of kyphotic angle : comparison between two groups.