The symptoms of dystonia occur when muscles of the body receive faulty information from the brain causing them to contract involuntarily. These faulty messages originate most commonly in a part of the brain called the basal ganglia. These messages are conveyed over brain pathways to the spinal cord and, from the spinal cord, reach the muscles via nerves.
Peripheral surgeries occur outside the brain and generally target the specific nerves and muscles affected by the incorrect messages from the brain. Peripheral surgeries are generally used to treat focal dystonia. An exception is intrathecal baclofen, which targets the spinal cord and is used to treat generalized or hemidystonia. However, for the purpose of this discussion, intrathecal baclofen is included under the category of peripheral surgeries.