- Published: October 29, 2013
Spinal tumors are abnormal masses of tissue within the spinal canal that can be classified anatomically into two groups:
(1) intramedullary: those that originate within the spinal cord, either as a primary growth or from metastatic spread
(2) extramedullary: those arising outside of the spinal cord, either from within the dura mater lining (intradural) or outside the dura mater lining (extradural).
The majority of spinal tumors are extradural, resulting from metastatic disease such as breast, prostate, and lung cancer.
Approximately 10,000 Americans develop primary or metastatic spinal cord tumors each year. Overall, 70% of spinal tumors are malignant, metastatic lesions. Primary spinal tumors are much less prevalent; however, the majority are benign (non-cancerous). The most common symptom in patients with spinal tumors, whether benign or malignant, is non-mechanical back pain that is usually worse when lying down. Pain, along with neurological deficits ranging from slight weakness to complete paraplegia, develops due to compression of the spinal cord or nerve roots. Additional symptoms, such as loss of sensation, loss of bladder/bowel function, and/or spinal deformity may arise depending on the tumor location. Diagnosis relies on mainly MRI and/or CT scans to definitively visualize the tumor and assess the risk of cord compression. Biopsy and/or surgical removal are needed for a definitive diagnosis.
The goal of treatment for spinal tumors is to reduce or prevent nerve damage from spinal cord compression. Treatment is divided into surgical and non-surgical approaches:
Tumors that are asymptomatic to mildly symptomatic are likely benign and may simply be monitored with regular MRI scans. Corticosteroids may reduce symptomology by decreasing swelling and any associated inflammatory reaction in patients with nerve/cord compression. Radiation and/or chemotherapy therapy may be used to treat inoperable tumors or following surgery to treat tumor that could not be completely resected. Radiation may be the first-line treatment in metastatic spinal tumors. Finally, stereotactic radiosurgery (Gamma Knife) is an advanced form of radiation that delivers treatment directly to the tumor, causing less impact to healthy tissue.
Indications for surgery depend on several factors such as the type and location of the tumor, intractable pain, spinal cord compression, and the need to stabilize the spine with impending fractures. Primary spinal tumors may be amenable to complete surgical resection while others may be partially resected to relieve pressure on the spinal cord.
Metastatic tumors warrant a palliative approach which may involve surgical techniques to also alleviate pain, stabilize the spine, and restore/preserve neurologic function.
Focused Ultrasound Research
Focused ultrasound (FUS) is not approved to treat spinal tumors. However, it has been shown to be a promising tool for pain palliation of bone metastases through local bone denervation. Guided by magnetic resonance imaging, the physician is able to heat the targeted bone and bone-tissue interface where the nerves reside. This beam destroys the pain-reporting nerve fibers, thereby blocking their ability to transmit pain signals. This non-invasive, radiation-free method may even directly damage tumoral tissue in the targeted region through localized thermal ablation. As such, spinal tumors may be amenable to both pain palliation and shrinkage through the use of FUS. However, as the ultrasound beam is unable to penetrate through bone to target tumors within the spinal canal, surgical removal of the posterior spinal elements may be necessary before FUS can be used.
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