Functional neurosurgery

Functional neurosurgery focuses on adjusting the functions of neural networks involved in movement, spasticity, pain or behavior. By modulating certain groups of neurons, the surgeon can increase or decrease neural activity for therapeutic purposes.

MRI-guided focused ultrasound (MRgFUS) is an innovative technology that uses a helmet emitting a multitude of high-energy ultrasound beams to create small brain lesions in a strategic location.

Currently, the indications for this treatment are disabling essential tremor that is drug-resistant or drug-intolerant, and Parkinson's disease with a tremulous, asymmetrical form that is disabling despite optimized drug therapy. Other rarer forms of tremor may also benefit from this type of procedure, such as Holmes tremor or cerebellar tremor. Akinetorigid syndrome in Parkinson's disease and disabling dystonias will likely become an indication in the future.

The treatment is performed in an MRI suite to ensure optimal target control. The procedure lasts approximately 3 hours. There is no anesthesia, except for local anesthesia of the skin to fix a so-called stereotaxic frame. There is no tissue incision. Focused ultrasound waves propagate through the skull and concentrate on a target precisely chosen by the neurosurgeon. The ultrasound energy is gradually increased, which induces an increase in tissue temperature. With low energy, a reversible effect on tremor is achieved, allowing the correct position of the future lesion to be verified using MRI thermometry. The medical team then clinically tests the treatment's effectiveness and the absence of side effects. Once the therapeutic zone is defined, the temperature is raised, allowing for a small, permanent lesion. The beneficial effect is immediate. There is an improvement in function and quality of life. Tremor may partially recur, but most patients maintain a lasting and significant improvement in their quality of life.

Side effects are very minimal. There may be some discomfort during the procedure in the form of headaches, dizziness, or nausea. After the procedure, tingling around the mouth and difficulty speaking or walking may occur. In the majority of cases, these side effects are transient, with a low risk of long-term residual deficit.

The main contraindication to this treatment is conditions with an increased risk of bleeding, particularly patients with intracranial arterial aneurysms and those in whom it is not possible to discontinue their anticoagulant or antiplatelet therapy two weeks before the procedure and a few days after. Furthermore, eligibility for this treatment depends on skull density, which varies from person to person (approximately 10% of patients are ineligible).

The MRgFUS procedure requires a pre-intervention assessment lasting several days, performed in the hospital. The purpose of this assessment is to ensure the patient's eligibility.

This is a technique used in neurosurgery to precisely reach hard-to-reach areas of the brain. It allows deep brain biopsies, high-precision focal radiotherapy, or the implantation of deep brain electrodes to be performed.

This approach was first used for movement disorders such as in Parkinson's disease. More recently, it has proven effective in specific cases with psychiatric disorders such as Tourette's syndrome, obsessive-compulsive disorder (OCD) and depression. Deep brain stimulation is used at the University Hospitals of Geneva through multidisciplinary collaboration with the Neurology Division.

Pain can be surgically relieved if the cause is neurological. This is the case with some diseases such as trigeminal neuralgia if it responds poorly to drug therapy. Several techniques can be used such as ablations or the modulation of specific parts of the nervous system.

Spasticity is a disorder of the motor system characterized by involuntary contractions of the muscles. It can occur in the context of many cerebral and spinal (spinal canal) pathologies. The placement of an intrathecal Baclofen pump reduces symptoms and promotes neuromuscular function.

Radiosurgery is a non-invasive technique. It can treat benign tumors, brain metastases and some arteriovenous deformities without the need for surgery. Using a beam of rays, it irradiates the relevant area of the brain very precisely. Before each radiosurgery, a multidisciplinary discussion takes place to ensure optimal treatment.