Permanently altering brain function, outside the skull

A surgical team from Italy have just reported that they’ve altered human brain function through neurosurgery conducted from outside the skull, by using beams of radiation.

The technique is known as radiosurgery and, in itself, isn’t novel. The team used the Cyberknife system, specifically designed to do this sort of operation.

However, the technique is typically used to treat brain tumours, and what is new is that the team have adapted this method to permanently knock out targeted areas to alter overall brain function.

They were inspired by deep brain stimulation and functional brain surgery. These aim to do a similar thing and are most commonly used to treat tremors and movement problems in Parkinson’s disease by altering the movement circuits in the brain.

This new operation aimed to do something similar, but with radiosurgery.

Their report appears in the journal Medical Physics, where they describe the treatment of two patients with, until then, untreatable disorders. One with chronic pain, stemming from nerve damage, and other with dystonia, a neurological disorder that causes certain muscles to painfully contract.

One of the challenges with this sort of operation is hitting exactly the right spot, and to achieve the necessary accuracy the team built a 3D computer model of the key areas from the brain scans which they then used to electronically direct the radiosurgery equipment.

The patient with dystonia had a pallidotomy, where part of his basal ganglia was ablated (destroyed), whereas the patient with chronic pain had a thalamotomy, taking out a section of his medial thalamus.

Both patients recovered well, significantly improved and showed no major side-effects at 15 months.

The image on the left shows where the radiation beams entered the head during the operation on the patient with chronic pain.

Link to research report.
Link to PubMed entry for same.