Metastatic Tumors of the Spine: Diagnosis and Treatment.
Metastatic disease of the spine occurs in as many as 70% of patients with disseminated cancer and may result in vertebral collapse, spinal instability, and progressive neurologic compromise. Today, magnetic resonance imaging is the most effective means of differentiating benign from malignant causation of vertebral collapse, based on the imaging patterns and extent of marrow ablation. The more rapid the onset of the neurologic deficit, the worse the prognosis for recovery, no matter what treatment is instituted. The majority of vertebral lesions requiring decompression and stabilization emanate from the vertebral body and are best managed by anterior decompression and stabilization alone. With posterior element destruction, spinal subluxation through the involved segment, or involvement of the lumbar spine, a combination of both anterior and posterior stabilization is required. The author's preference is to perform anterior vertebral replacement with methylmethacrylate incorporating a Knodt distraction rod. This construct affords instantaneous stability that is not adversely affected by postoperative irradiation. Many devices can provide adequate posterior stabilization, but the author prefers to use Luque rods with sublaminar wire fixation. In a series of 77 patients with major neurologic compromise treated with this technique, 62% showed improvement by at least two Frankel grades, compared with fewer than 5% who improved after laminectomy decompression with or without irradiation. Nineteen of the 77 patients remained alive more than 4 years postoperatively.