The significance of spinal fixation in palliative surgery for spinal metastases.

The purpose of this study is to assess appropriate fixation methods for surgical spinal stabilization for spinal metastases. 191 patients who underwent spine surgery for spinal metastases are included in this study. The surgeries included 1) posterior decompression only (29), 2) posterior decompression and fixation (153), and 3) decompression and circumferential fixation (9). We evaluated and compared all cases based upon 1) use of fixation, 2) number of levels included in the fixation, 3) type of fixation, 4) use of bone graft, 5) presence of preoperative collapse of involved vertebrae, and 6) involved area of vertebrae according to Kostuik classification. Progression of vertebral collapse on radiographs or Magnetic Resonance Imaging (MRI) or occurrence of implant failure after surgery was considered a failed case. The number of failed cases was 51 (27%). The factors that were compared between the failed and successful groups were: use of fixation (p < .01), extent of fixation (one level above and one level below affected vertebrae vs. ≧ two above and two below, p < .01), presence of preoperative collapse of affected vertebrae (p < .05), and ≧ four of six columns of vertebral involvement according to Kostuik classification (p < .01). All results were statistically significant. In conclusion, when treating metastatic spinal disease with instability, it is recommended that posterior fixation with instrumentation be used and extend at least two levels above and two below the affected vertebrae. Preoperative collapse of affected vertebrae and greater involvement of the vertebrae with metastatic disease results in greater local instability.