The story of Gavin Pierson, the 8-year-old Ramsey, Minnesota, boy battling a brain tumor, includes a number of key players: his doctors, parents, siblings and care team, and the thousands of people who have followed his two-year fight against the aptly nicknamed "Joe Bully."
But one of Gavin's most important allies doesn't have a degree, voice or personal Facebook page.
Visualase, an MRI-guided, minimally invasive laser system, has been the Kryptonite to Gavin's tumor since he became the first person with a mature teratoma brain tumor to undergo the procedure. His first laser surgery took place on Oct. 29, 2013, at Children's Hospitals and Clinics of Minnesota and his second four months later on Feb. 20, 2014.
"There are many things that make this procedure unique. One is the use of MRI, which allows us to monitor the temperature of both the tumor and the normal brain during the laser treatment," said Joseph Petronio, MD, medical director of pediatric neurosurgery at Children's and the doctor who led Gavin's Visualase procedures. "The composition of (Gavin's) tumor is unusual, including elements of bone and skin that makes it conduct heat very broadly. By being able to monitor temperature that closely, we are able to target the tumor more precisely without damaging other tissue."
Founded in 2005, Visualase, Inc.'s system is a minimally invasive laser procedure that allows surgeons to pinpoint and treat lesions and tumors with extreme precision.
So, how does Visualase work?
- Visualase Cooled Laser Applicator System:The system features a disposable fiber optic catheter with a built-in cooling mechanism that prevents overheating near the surface of the applicator. This laser catheter is placed through a small opening in the scalp and skull and into the center of a tumor using advanced MRI technology. Laser energy is then used to heat the tumor carefully. The system was engineered to allow for the use of higher laser powers to destroy tumors with shorter exposure times.
- Laser generator:The generator produces light energy that is used to thermally ablate, or destroy, soft tissue.
- Workstation:The workstation interfaces with an MRI to allow temperature control and monitoring in real time during a treatment. It also provides on-screen visuals of the tissue as it turns into a solid or semi-solid state. Because of the in-depth monitoring, the procedure results in a high level of precision and control.
- Temperature:The time it takes to destroy parts of the tumor depends on the temperature of the laser. When set to 113-140 degrees Fahrenheit, tumor cells eventually get destroyed. Cells and tissue are destroyed immediately when the laser is between 140-212 degrees. Anything above 212 degrees, though, can cause water in the tissue and areas inside a cell to vaporize, and leads to ruptured cells and tissue components.
- According to Visualase, once soft tissue is destroyed, or ablated, it is considered non-viable and is reabsorbed, leaving little evidence that a tumor or burn existed.
After getting its start in treating liver and prostate problems, the Visualase Thermal TherapySystem was cleared by the Food and Drug Administration in 2007 for the ablation of soft tissue in neurosurgery. Visualase's first minimally invasive neurosurgical procedures were performed in 2006 in Paris as part of a study for treating brain tumors.
The Visualase laser system is in use at more than 40 hospitals, nationwide, including 15 pediatric hospitals. In pediatric patients, including at Children's Hospitals and Clinics of Minnesota, Visualase has also been used to address brain lesions that cause epilepsy.
"What's exciting to me is the path this technology opens to areas of the brain that were closed to us before," said Petronio. "To think we could reach a day when the term 'inoperable brain tumor' in children is obsolete is extraordinary."