Surgical Treatment of Essential Tremor

When medications are not effective, one additional option is surgery to destroy the abnormal brain cells that are responsible for the tremors. These cells are located deep in the brain in the thalamus in a bilateral structure called the basal ganglia. There are several nuclei (collections of brain cells) in the thalamus, but the one that is related to tremors is called the ventral intermediate nucleus (VIN). The operation, thalamotomy, can be done by conventional stereotatic surgery or by the use of a Gamma knife (which uses radiation). Since there is one thalamus in each side of the brain, the thalamotomy could be unilateral or bilateral. An additional option is by deep brain stimulation (DBS) with implanted electrodes.

These techniques have proved to be very effective in some patients but are not free of side effects. At the present time the following are accepted recommendations:

• Unilateral thalamotomy is indicated when the tremor is predominant or limited to the contralateral limb. It might also be indicated in disabling bilateral limb tremor that is refractory to medication.
  
  
• Bilateral thalamotomy might be indicated in cases of severe bilateral tremor; however, the frequency of the side effects is a limiting factor.
  
  
• Deep brain stimulation is also effective for reducing a contralateral tremor.
  
  
• Both approaches seem to be effective in the suppression of limb tremors. DBS seems to have fewer post-operative complications, but requires more monitoring and adjustments after the operation. The ultimate decision depends upon the individual patient.
  
  
• There is conflicting information regarding the use of surgery or DBS for the treatment of voice or head tremors.