Preliminary Efficacy of Combination Decompressive Surgery, Stabilization and Cyberknife Radiosurgery: A New Treatment Paradigm for Metastatic Spinal Tumors with Cord Invasion

Abstract

Objective:The goal of this retrospective study was to assess clinical and radiographic outcomes of posterior surgical decompression with stabilization followed by image-guided robot Cyberknife radiosurgery for encircling malignant tumors of the spine. Methods: From August 2008 to December 2009, 14 consecutive patients with a malignant spinal metastatic lesion with cord compression were treated at the author's institute. Patients underwent on a decompressive surgery by the posterior approach, and latent unstable spines were stabilized with instrumentation. After recovery, radiosurgery was administered at doses ranging from 16 to 26 Gy (mean 20.1 Gy) prescribed to the 75-85% isodose line that encompassed at least 95% of tumor volumes. Visual Analogue Scale, American spine injury association grades, and MRI with gadolinium enhancement were used to monitor pain, neurology, and radiological outcomes, respectively, after the radiosurgery. Results: No acute radiation-induced toxicity or new neurological deficit occurred during the follow-up period (mean 4.5 months). Axial pain improved in 10 out of the 14 patients. No hardware failure was encountered. At 3-6 months after the Cyberknife radiosurgery, local control and effective therapeutic rates were both 80% (8/10) and no lesion enhancement on vertebral bodies or pedicles was visualized by MRI. Conclusion: Posterior decompression with stabilization followed by radiosurgery of residual tumor in the anterolateral region is useful in cases where an anterior approach or a circumferential approach is not an option due to medical condition. Longer term follow-up is required to evaluate survival and late toxicities.