Monday, July 15, 2013

The CyberKnife Advantage

By: Blake Pearson, MD

Over the last decade, radiosurgery has revolutionized the practice of neurological surgery, allowing radiation oncologists and neurosurgeons to provide safe, non-invasivetreatment. Brookwood Medical Center is the only facility in Central Alabama that offers CyberKnife©technology, and numerous patients have benefitted from this painless alternative to traditional surgery for the treatment of both cancerous and non-cancerous tumors.

Cyberknife© radiosurgery is performed collaborativelyamong a neurosurgeon, a radiation oncologist and a radiation physicist. CT and MR-images are used to create a three-dimensional model of the patient’s pathology and the surrounding normal anatomy. A focused high dose of radiation is delivered in a series of beams from a linear accelerator placed on a robotic arm at multiple angles, focusing the radiation at a high dose within the pathologic structure and minimizing the dose to surrounding, healthy structures. Because no head frame is used, the radiation can be fractionated or delivered in a single session, depending on the needs of the case and the pathology being treated. 

In years past, the treatment of metastatic brain tumors was whole-brain radiation and relatively short life expectancy. The use of CyberKnife© allows treatment of multiple intracranial metastases and intracranial metastases in surgically inaccessible areas with very limited morbidity. CyberKnife’ s relatively unique ability to deliver radiosurgery in a fractionated method allows the dose of radiation to be split up over several days, and radiobiologically, this allows a higher dose to be delivered to the tumor than to the surrounding normal structures, reducing the risk of radiation necrosis and allowing treatment of slightly larger tumors. With the CyberKnife© innovation, we have moved away from recommending whole-brain radiation as an initial treatment, since patients will start to develop neurocognitive effects of radiation exposure.

In addition to the treatment of metastatic tumors, CyberKnife© is an outstanding tool for the treatment of meningiomas and acoustic neuromas. CyberKnife© can also treat trigeminal neuralgia, and in my practice, has completely replaced percutaneous rhysolysis as a minimally-invasive option. While the effectiveness still lags slightly behind open microvascular decompression, the minimal risk profile and elimination of the anesthetic risks and avoidance of a craniotomy are very appealing, especially in the elderly population, who are most affected by trigeminal neuralgia.

CyberKnife©can also treat spinal lesions outside the cranial vault, allowing very aggressive management of spinal tumors and warding off cases of tumor-associated paralysis and tumor-associated spinal column collapse before they ever occur. Typical radiation delivery methods provide large doses of radiation to paraspinal wounds and are well known to lead to severe wound complications. CyberKnife© radiosurgery targets the radiation dose directly to the wound and prevents complications, providing a substantial improvement in both quality and longevity of life compared to traditional neurosurgery methods.

Blake Pearson
is a neurosurgeon with Brookwood Medical Center.

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