The small man has been plagued with tremor since his diagnosis of Parkinson’s disease more than twenty years ago. He comes in to the examination room with his wife and a packet of information under an arm. He has the blank visage of a PD patient. When the doctor questions what he’s brought with him though, his expression breaks and he looks almost excited. With the papers in his hands, they flutter about and his wife intercepts them. The patient takes a seat. The hands are moving and distracting him and his wife places the pages on the physician’s desk. The doctor pauses and looks at what they have brought in.
The information from the Michael J. Fox Foundation for Parkinson Research internet site and describes a study of 183 patients with essential tremor or tremor brought on by PD. The study and results were presented in a poster session two years ago, on November 2, 2009. The American Society for Radiation Oncology released a report for the press. They called the intervention, “a less invasive way to eliminate tremors caused by Parkinson’s disease and essential tremor than deep brain stimulation and radiofrequency treatments, and is as effective, according to a long-term study presented November 2, 2009 at the 51st Annual Meeting of the American Society for Radiation Oncology. “The study shows that radiosurgery is an effective and safe method of getting rid of tremors caused by Parkinson’s disease and essential tremor, with outcomes that favorably compare to both DBS and RF in tremor relief and risk of complications at seven years after treatment,” Rufus Mark, M.D., an author of the study and a radiation oncologist at the Joe Arrington Cancer Center and Texas Tech University, both in Lubbock, Texas said. “In view of these long-term results, this non-invasive procedure should be considered a primary treatment option for tremors that are hard to treat.”
The doctor shakes his head and comments that destroying a small region of the brain to control involuntary movements is not a new idea. There’s evidence that prehistoric man drilled holes in the skull, perhaps to release evil spirits or to still tremor. He explains to the patient and his wife that this method uses a beam of radiation to essentially thermo-coagulate an area of tissue, and goes under different names- Cyberknife, Gamma Knife and Synergy are a few. The target is the Ventralis Intermedius nucleus or VIM. Different strengths of radiation have been tried, with varying results.
The wife reads from the sheet in her hand, “With a median follow-up of seven years, 84 percent had significant or complete resolution of tremors. In patients with Parkinson’s disease, 83 percent had near or complete tremor resolution, while those with essential tremor had 87 percent of this degree of tremor resolution.”
The patient is not able to undergo deep brain stimulation, as he has metal bits embedded in his body and brain from his years spent in Vietnam. DBS surgery requires the patient have an MRI of the brain, something not possible for a person with metal shards, since the magnetic field may cause the metal to move, creating internal bleeding. Stereotactic surgery can be performed with the use of a CT, rather than an MRI, to position the beam of radiation.