Traditional brain surgery, performed via a craniotomy, can result in long recoveries and potential complications. Over the past decade, a new procedure, transorbital neuroendoscopic surgery, or TONES, has offered a different route to the pathology of the brain and skull base, eliminating the need to remove part of the skull.
Transorbital neuroendoscopic surgery
Kris Moe, MD, FACS, a head and neck surgeon and chief of Facial Plastics and Reconstructive surgery, pioneered TONES in 2010 along with Richard G. Ellenbogen, MD, FACS, a neurosurgeon and professor and chair of the Department of Neurological Surgery, and Moe’s fellow at the time, Chris Bergeron, MD.
The procedure is a less disruptive way to access the skull base — a set of five bones supporting the bottom of the brain — to remove tumors, treat aneurysms, fix cerebrospinal fluid leaks, repair skull and orbital fractures, and more. Surgeons go in through a two-centimeter incision above the eye and use an endoscope, which Moe describes as a “small telescope.”
“The orbits reach back almost to the center of the skull, so between both of them you can access many parts of the brain, and by going around the eye you already have a little tunnel through which you can get way back into the head without retracting the brain,” Moe says.
TONES is sometimes referred to as transorbital skull base surgery. The eye is protected in the orbit, says Jacob Ruzevick, MD, a neurosurgeon who specializes in neuro-oncology and skull base tumors.
When Moe and Ruzevick work together, Moe guides the endoscope while Ruzevick removes the tumor. They’re both working through the same two-centimeter incision.
“We call it a dance,” Ruzevick says. “You have to dance with your partner to achieve the best outcome.”
Benefits for patients
Moe likes to call TONES “minimally disruptive” rather than “minimally invasive” because the tumor or other reason for surgery is already invasive. But the treatment doesn’t have to disrupt the patient’s life completely.
“We can be minimally disruptive to your lifestyle, to how you function, and get you back to your quality of life as soon as possible with rapid recovery, less expense, a shorter hospital stay and less time needed off work,” he says.
Most patients don’t even develop a scar. If they do, it’s small and covered by the eyelid.
Depending on the location, size and other factors of the tumor or other problem to be fixed, the surgery also takes much less time than a craniotomy. Since the incision is so small, there’s less pain and less recovery time, with some people able to go home the same day as the procedure.
“It makes patients feel a lot easier going into surgery,” Moe says. “For example, one of my recent patients said he had no pain after.”
Of course, no surgery is without risk, though lasting complications are rare for TONES patients.
“When you retract the eye, the lens of the eye gets deformed temporarily, and temporary blurry vision can happen,” Ruzevick says. “But it almost universally resolves.”
On the forefront of neurosurgery and neuro-oncology
As a first step, Moe and Ruzevick must decide whether a patient qualifies for TONES — and there are several factors to consider.
“It depends on the structures involved. What critical structures are adjacent to the tumor and is the tumor invading them? What’s the size of it? Are there blood vessels feeding it or around it? Is the optic nerve near it?” Moe says. It’s a complex analysis that takes a wealth of experience, a factor owing to UW Medicine’s leadership in the field, given Moe’s pioneering experience.
It’s also why there are few surgeons in the United States who can perform TONES. However, Moe says, that is starting to change as international adoption of the technique has accelerated.
A patient’s personal health history matters too when determining if they are eligible, though Moe and Ruzevick have successfully operated on everyone from infants to individuals in their 90s.
Moe and Ruzevick sometimes also work with an ophthalmologist, depending on the location of the surgery.
“I am incredibly grateful and humbled to do this for people. It feels great to be on the forefront of neurosurgery and neuro-oncology,” Ruzevick says. “You always want to be constantly improving to minimize stress, harm and pain for patients, and this is a natural avenue to do just that.”
Moe agrees. “It’s really rewarding to see patients recover so quickly,” he says. “I really enjoy my work. It gives me a lot of satisfaction.”