Fusion Can Prevent Spinal Deformity Following Intramedullary

Introduction: Spinal deformity is a common development following laminectomy and resection of pediatric intramedullary spinal cord tumors. While risk factors for post-laminectomy deformity have been well-documented, few reports have evaluated the efficacy of a preventative surgical approach. The current study is a multi-center update from our initial study which demonstrated the ability of fusion at the time of tumor resection to prevent post-resection spinal deformity.

Methods: Retrospective review of 255 children with spinal cord tumors treated at two tertiary pediatric cancer centers between 1960-2002. Of these, 52 patients with a biopsy-proven intramedullary spinal cord tumor had complete clinical records and radiographic data. Pre-operative spinal alignment, surgical treatment, post-operative deformity, and risk factors for deformity were evaluated. All patients had at least two years follow up.

Results: There were 18 females and 34 males with an average age of 8.1 +/- 4.1 years. The average time to latest follow up was 7.6 +/- 5.3 years. Moderate or severe post-resection spinal deformity (scoliosis >25 o, sagittal plane abnormality >20o requiring bracing or surgery) developed in 57% (17/30) of resections without fusion (laminectomy or laminoplasty), and in 27% (4/15) of fusions (p=0.24). Excluding patients with tumor recurrence or paraplegia, however, 54% (14/26) of laminectomies and all three laminoplasties developed moderate or severe deformity at latest follow up, while only 17% of fusions did (2/8 in situ; 0/4 instrumented) (p=0.02). Among skeletally mature children, 67% (16/24) developed deformity following laminectomies and laminoplasties, compared with 13% (1/8) of fusions (p=0.001). Removal of greater than 3 lamina (p<0 .04), but not age at surgery or junctional tumor location, were risk factors for deformity.

Discussion: These findings confirm our previous conclusion that, in patients without tumor recurrence or paraplegia, instrumented and in situ fusion performed at the time of spinal cord tumor excision significantly lowers the risk for developing post-resection spinal deformity. All three laminoplasties, however, developed significant deformity.