Stereotactic Radiosurgery for the Management of Intradural Neoplasms of the Cervical Spine

Stereotactic radiosurgery (SRS) is increasingly utilized for the treatment of spinal neoplasms. Microsurgical resection remains the first-line treatment for most intradural neoplasms. However, the use of radiotherapy for metastatic intradural and intramedullary lesion of the cervical spine is also well established and there is also a growing body of evidence regarding the use of radiosurgery for the treatment of benign intradural spinal neoplasms. Conventional radiotherapy is usually performed with a 5–10mm planned treatment volume (PTV) expansion around the gross target volume (GTV) to account for setup and imaging uncertainties. For tumors that are adjacent to the spinal cord, this means that a significant portion, often including the entire circumference of the spinal cord at the level of the tumor, will be treated to the same dose as the tumor. The sharp dose fall-off from radiosurgery treatment volumes with little or no additional margin allows for SRS of tumors adjacent to the spinal cord using doses higher than what the spinal cord receives. Even if a radiation injury occurs following SRS, it would be far less likely to result in any permanent injury across the entire width of the spinal cord than an injury developing after conventional radiotherapy. Recent data also suggest that cervical spinal neoplasms respond favorably to SRS, with high rates of radiographic tumor control and clinical improvement. Pain is one of the main indications for radiosurgery, and many patients demonstrate symptomatic improvements. Treatment response varies, depending on tumor histopathology, location, and radiation dose applied. Especially in the cervical spine, the possible side effect of radiationinduced myelopathy may result in significant harm to quality of life, and other critical adjacent structures are also sensitive to radiotherapy. Nevertheless, radiosurgery is becoming an important treatment modality for intradural neoplasms of the cervical spine.