The article entitled The Current Surgical Management of Metastatic Spinal Disease, by Drs. Peter C. Gerszten and William C. Welch, is a timely, comprehensive review of the current state of the art in the diagnosis and surgical management of spinal metastatic disease. The authors begin by describing the clinical problem and noting the high prevalence of spinal column metastases and cord compression associated with breast, bronchogenic, prostatic, and other types of primary malignancies. They also note that this will likely become an even more common clinical challenge as diagnostic and oncologic treatment modalities continue to improve.
The authors proceed to describe an accepted clinical approach to the evaluation and diagnosis of these patients. The clinical presentation is reviewed, and diagnostic imaging modalities are discussed. Although plain films are an excellent screening tool, the authors emphasize the utility of magnetic resonance imaging (MRI) in the evaluation of metastatic disease. The advantages of MRI include increased sensitivity (eg, for noncontiguous lesions, which often are missed) and the ability to evaluate both cord impingement and soft-tissue extension. Thus, MRI has become the imaging modality of choice in the evaluation of spinal metastatic disease. The roles of computed tomography (CT) and nuclear studies are also discussed.
The authors then review the treatment options for spinal metastatic disease and the role of surgery in treatment. Indications for surgery can include a need for biopsy tissue, radioresistant tumors, spinal instability due to destruction of the bony elements, canal compromise, poor response to radiotherapy, tumor recurrence, and pain relief.
In discussing surgical indications, the authors make an important distinction. Radiotherapy was previously the universally accepted primary treatment for spinal metastatic disease, and this was due, in part, to the somewhat disappointing results of surgical treatment. However, many older series were based on the results of laminectomy to decompress the neural elements.
Laminectomy is a posterior procedure that was performed in the hopes of obtaining an indirect decompression of the neural elements. Because neural element compression with metastatic disease occurs most often ventrally (ie, tumors are most commonly found in the vertebral body), prior surgical treatment often did not produce an adequate decompression.
Modern surgical techniques have allowed direct anterior decompression. Spinal stability can then be effectively restored with bone graft or methylmethacrylate, and appropriate spinal instrumentation (cages, plates, and rods) can be applied both anteriorly and posteriorly. In most cases, surgical decompression and stabilization of the involved spinal segment should precede radiotherapy to avoid possible wound healing complications.
These modern techniques have led to a significant improvement in results compared to the historical results of laminectomy alone. Thus, surgery has become the treatment of choice in selected cases, and early surgical consultation can, at times, prevent unnecessary prolonged pain and neurologic deterioration. The authors emphasize the need for a multidisciplinary approach to these patients, including an in-depth discussion with the patient, his or her family, and other caregivers. The decision to intervene surgically must always be made in light of the patients prognosis and expected survival.
Surgical options in the anatomic regions of the spine are then explored. In the cervical spine, anterior corpectomy and reconstruction with autograft, allograft, or methylmethacrylate can be used when the tumor mass is primarily in the vertebral body and compression is occurring anteriorly. However, the anterior approach provides limited ability to approach posterolateral tumor masses. In these cases, a posterior laminectomy approach is best, but as the authors point out, there is the danger of possible posterior cord displacement if the cord is compressed anteriorly.
Thoracic tumors are then discussed, beginning with the problems associated with traditional laminectomy techniques, including progressive kyphosis and continued neurologic deterioration. Anterior approachesor in selected patients, posterolateral approaches (for example, costotransversectomy)are generally preferred. Minimally invasive tools such as thoracoscopy are exciting adjunctive options, which hold much promise for the future. Decompression and fusion techniques in the lumbar spine can be performed anteriorly, posteriorly, or with a combination of both approaches.
Finally, prognosis and complications are reviewed. The authors point out the high rate of neurologic recovery, with over 65% of previously paraplegic patients regaining functional ambulation. Neurologic outcome tends to be better in patients with incomplete deficits and those with a more gradual onset of symptoms.
Overall, the authors give an excellent, comprehensive review of the surgical treatment of metastatic spine disease, which is accessible and relevant to surgeon and nonsurgeon alike. The role of surgery continues to evolve but clearly is increasingly important. Timely reviews of the literature such as this one can help to better define that role and ensure that surgical modalities will be applied most appropriately to patients who will benefit most from them.
Christopher Michelsen, md