Anterior construct location following vertebral body metastasis reconstruction through a posterolateral transpedicular approach: does it matter?

Abstract

Object The posterolateral transpedicular approach (PTA) is a widely used method for the surgical treatment of vertebral body metastases. It is crucial to understand the optimal location of the anterior graft in terms of sound and durable reconstruction following PTA. The purpose of this study was to investigate whether postoperative construct stability is related to the location of anterior grafts. Methods The authors conducted a retrospective review of 45 cases of metastatic spine disease with epidural tumor extension in which patients underwent circumferential decompression and fusion by means of PTA. Mechanical (anterior construct stability), pain (visual analog scale score), and neurological (American Spinal Injury Association scale) outcomes were evaluated and correlated with the anterior graft location (lateral or central) and surgical approach (unilateral or bilateral), number of decompressed levels, types of anterior graft, screw density of posterior fixation (number of screws used divided by the number of pedicles spanned), and kyphotic angle change from the immediate postoperative period to the most recent follow-up. Results Seven of 45 constructs were judged unstable—5 with a lateral location of the anterior graft and 2 with a central location. The anterior graft was located laterally in 31 cases (69%), centrally in 11 (24%), and bilaterally in 3 (7%). A unilateral approach was used in 33 cases and a bilateral approach in 12. Neither the location of the anterior graft nor the approach had a significant effect on the stability of the reconstructed spine (p > 0.05). There was a significant difference in construct stability between the single-level decompression group (33 patients) and the multiple-level decompression group (12 patients) (p = 0.0001). The types of anterior graft, screw density, and kyphotic angle change were not correlated to the mechanical outcome. Conclusions The anterior graft location showed no significant relationship to the final mechanical, pain, and neurological outcomes.