UCSD surgeons, in collaboration with the University of Washington Medical Center, have developed a new technique in minimally invasive surgery that consists of surgeons inserting probes through tiny slits in the patient’s body and completing the operation in that way.

Head and neck surgeons from both university medical centers have  spent the past 10 years conducting research and fine-tuning the technique, which can now be safely used on patients.

The procedure, called TONES (transorbital neuroendoscopic surgery), allows surgeons to access the brain and skull base through the eye socket instead of the traditional method of removing the top of the skull.

Previously, surgeons also operated on patients through the nose, in between the eyes. But, due to its position, going through the nose restricts access to parts of the brain above and lateral to the eyes.

“Usually for procedures which require access to those parts, we would cut across the head from ear to ear, peel the face down and lift the brain,” Assistant Professor of Head and Neck Surgery Chris Bergeron said. “Using this new technique, we can avoid making incisions from ear to ear.”

Accessing the brain through the eye socket also avoids potentially harmful contact with the optic nerves (for eyesight), the olfactory nerves (for smell), and the carotid and ophthalmic arteries, which supply the head, neck and eyes with blood.

In addition, using a TONES procedure means a less crowded operating room, as just two surgeons can complete it.

The new procedure uses the fundamentals of traditional surgery. Endoscopes, a long surgical tool with a camera on the end, are widely used in sinus and brain surgery and are also part of the basic equipment used in TONES.

Surgeons use endoscopes to see inside the patient via a camera without making wide incisions.

Bergeron and his colleagues have safely performed the procedure on a series of 20 patients.

“The implications of minimally invasive procedures, such as TONES, include minimal morbidity with as little side effects as possible,” Bergeron said. “There is less disturbance of the surrounding tissue and structure.”

Patients with procedures performed using TONES reported fewer post-operative days in the hospital, less pain, and minimal or non-visible scarring.

Using TONES, cerebral spinal fluid leaks and tumors both inside and outside of the brain can be accessed and treated.

Surgical procedures on the optic nerves can also be performed using this technique, as well as fracture repairs on the cranial skull base.

“This procedure also holds promise for trauma cases,” Bergeron noted. “We can attempt to fix a leak from the top without a big incision. It is also a new way of approaching anterior skull base lesions.”

With further research, surgeons hope to make TONES applicable to tumors in the pituitary gland, tumors on the meninge — also known as meningiomas — and vascular malformations, or abnormalities of the blood vessels near the head.