J Korean Soc Spine Surg.  2011 Sep;18(3):103-110.

Efficiency of Implant Removal for Treatment of the Thoraco-lumbar Unstable Fractures: Multi Segments Fixation, Single Segment Fusion

• Park HJ
• Shim YJ
• Kim WK
• Cho TY
• Kwon SM

Abstract

STUDY DESIGN: A retrospective study.
OBJECTIVES
To evaluate the safety and usefulness of implant removal based on fusion by radiological change analyses and non-fused segment motion angle after open reduction, multi-segment fixation, and single segment fusion. SUMMARY OF LITERATURE REVIEW: There have been reports that discuss possible fracture of fixator, loss of reduction, or failure of fixation in certain cases of single segment fixation consistent with thoracolumbar fracture.
MATERIALS AND METHODS
We analyzed 83 patients who had undergone treatment by fixation of the top 2 segments and the bottom segment. The posterolateral fusions were performed for the top segment for thoracolumbar fractures. The mean follow-up was 21.3 months. Wedge and local kyphotic angles, anterior, and posterior heights of the vertebral body were measured on plain radiograph. The range of motion of each segment was recorded by flexion-extension lateral radiographs at 6 month after the removal of implants.
RESULTS
Radiologic assessments performed on 83 patients demonstrated preoperative mean wedge angle, kyphotic angle, mean anterior body height of 20.1degrees, 18.5degrees and 62.0%, respectively, and, postoperatively, these were corrected by 9.0degrees, 9.3degrees and 24.6%, respectively. In the 44 cases that had the implants removed, the correction losses were 0.4degrees(P=0.258) and 3.7degrees(P=0.000), 0.5%(P=0.756), and at the last follow-up, compared to measurements prior to the removal. There was no statistical significance in wedge angle or anterior body height. The range of motion measured on the non-fused segment was 3.9degrees on average at 6-months after the hardware removal.
CONCLUSIONS
The multi-segments fixation and single-segment fusion for the thoracolumbar fracture can preserve correction and the motion of non-fusion segment. Although the implant removal after union can sustain motion, further studies regarding degenerative change of the non-fused segment are necessary.

Keyword

Thoracolumbar spine; Fracture; Pedicular screw; Implant removal

MeSH Terms

Body Height
Follow-Up Studies
Humans
Range of Motion, Articular
Retrospective Studies

Figure

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  Fig. 1. Radiography showing linear and angular measurement. : Wedge angle(∠ CD°), Local kyphotic angle(∠ AE°), Sagittal index(∠ BD°: if T11,∠ BD-5 and if L2,∠ BD+10), Anterior body height(200ⅹ b/(a+c) %), Posterior body height(200× e/(d+f) %)

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  Fig. 2. A 41-year old male with flexion-distraction injury on L2. (A) Preoperative lateral roentgenogram shows fracture of L1 spinous process (B) Lateral radiograph, immediately after surgery, shows anatomical reduction. (C,D,E) Lateral roentgenogram of neutral/flexion/extension views that show range of motion of no fusion segment

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  Fig. 3. The radiologic change of angular measurement

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  Fig. 4. The radiologic change of linear measurement

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