Decompression or Stabilization
The spine is the most common, and most clinically challenging, site of bony metastasis (Abel et al. 2008). Individual functional status and overall disease prognosis vary considerably, and this leads to significant heterogeneity in the management of the spinal metastasis. In many individuals with symptomatic compression of the spinal cord, the cancer has progressed to a point where surgical intervention is not considered curative. Rather, the rationale for surgery and (neo)adjuvant chemotherapy or radiation is to relieve pain and to prevent or reverse neurologic deficits.
Attempts to decompress the spinal cord or stabilize the spine may employ an anterior, posterior or combined approach. Specifically, the mechanical instability and extent of cord compression caused by the lesion will affect the surgical strategy. While many studies have compared the outcomes of such procedures, unfortunately, most groups include individuals with variable pre-operative neurological deficits and do not provide enough details regarding neurological outcomes. However, as summarized in Table 9, several studies have aimed to determine the possible advantages of different surgical approaches.
Discussion
Bony metastasis in the spine is most commonly encountered in individuals with multiple myeloma, breast or prostate cancer. These lesions may lead to pathologic fractures and usually cause significant pain. Moreover, compression of the spinal cord and the resultant neurologic deterioration is a challenging complication. These findings represent disease progression and usually herald poor survival prognosis.
Numerous groups have proposed treatment strategies and reported the efficacy of surgical and adjuvant therapies (Abel et al. 2008; Chong et al. 2012; Gokaslan et al. 1998; Rompe et al. 1999). Treatment is aimed at preventing further neurologic deficits and for pain control. Surgical options include anterior, posterior or combined approaches for decompression and/or stabilization.
Above, we have summarized several well-designed studies which report surgical outcomes for individuals with metastatic spine lesions. As metastatic lesions most commonly arise within the vertebral body, anterior procedures or combined approaches are usually preferred for decompression. Gokaslan et al. (1998) reported the outcomes for 72 individuals with metastatic lesions who underwent trans-thoracic vertebrectomy. In this series, significant improvements in neurologic status and functionality were noted in 76% of individuals and pain was decreased in 92% of individuals.
While anterior procedures usually allow greater decompression, some individuals may not tolerate the procedure and others may also need posterior stabilization. Abel et al. (2008) report significant improvements in individual pain after posterior decompression and stabilization. They prevented progressive neurologic decline in 87% of individuals and functional status improved significantly in their individuals.
Conclusion
Given the heterogeneity in individual status, lesion characteristics and variations in surgical experience it is likely futile to argue for the superiority of a certain approach for decompression or stabilization for compression by metastatic lesions. Instead, the surgical technique should be individualized to achieve the objectives safely.
