Innovation for Parkinson's and Essential Tremors
Deep Brain Stimulation (DBS) is a surgical procedure to implant a pacemaker-like device that sends electrical signals to brain areas responsible for body movement. Electrodes are placed deep in the brain and are connected to a stimulator/battery device. Similar to a heart pacemaker, a neurostimulator uses electric pulses to help regulate brain activity. DBS can help reduce the symptoms of tremor, slowness of movement, stiffness, and walking problems caused by movement disorders.
What is Deep Brain Stimulation (DBS) Surgery?
DBS surgery involves placing a thin metal electrode (about the diameter of a piece of spaghetti) into one of several possible brain targets and attaching it to a computerized pulse generator, which is implanted under the skin in the chest below the collarbone. All parts of the stimulator system are internal; there are no wires coming out through the skin. A programming computer held next to the skin over the pulse generator is used during routine office visits to adjust the settings for optimal symptom control. Unlike older lesioning procedures or gamma knife radiosurgery, DBS does not destroy brain tissue. Instead, it reversibly alters the abnormal function of the brain tissue in the region of the stimulating electrode. It is important to note that DBS therapy may demand considerable time and patience before its effects are optimized.
How does DBS work?
Deep Brain Stimulation is not a cure for movement disorders, but it can successfully treat symptoms by disrupting the abnormal patterns of brain activity that become prominent in these diseases. DBS is often described as a brain pacemaker because constant pulses of electrical charge are delivered at settings that are thought to restore normal brain rhythms, allowing the restoration of more normal movements. The exact mechanisms of this neuromodulation are still unknown.
How is DBS surgery performed?
DBS electrode placement in the awake patient either with or without a stereotactic head frame has been the gold-standard for the past fifteen years. Henrico Doctors' Hospital also offers this technique while patients are sleeping, a new innovation in the procedure.
The technique we currently use for traditional awake DBS is frameless. Instead of the traditional stereotactic head frame we use 5-6 pins, called fiducials, which are placed in the skull using local anesthesia. A brain imaging study is obtained with the pins in place. The images of the brain are used to select the target in the brain and plan a trajectory that minimizes the risk of complications.
In the operating room, light intravenous sedative is given and then after making the scalp completely numb, an incision is made on top of the head behind the hairline and a small opening, less than the size of a quarter, is made in the skull. If both sides of the brain are to be implanted, the skull opening is made on both sides before sedation is stopped and the patient is fully awoken.
A tower is then built over the hole that is used to deliver the electrode to the target. First brain mapping using hair-thin microelectrodes is used to record brain cell activity in the region of the intended target to confirm that it is correct, or to make very fine adjustments in the intended brain target to try and find the optimal location. The brain's electrical signals are played over a speaker so that the surgical team can listen for distinctive patterns of neuronal activity that indicate the location of the recording electrode.
When the correct target site is confirmed with the microelectrode, the permanent DBS electrode is inserted and tested for about 20 minutes. The testing will look for improvement in symptoms such as tremor and muscle stiffness. In addition we will confirm that therapeutic stimulation is not causing side effects. We also turn the device up to a higher intensity than is normally used, in order to deliberately produce unwanted stimulation-induced side effects (such as tingling in the arm or leg, difficulty speaking, a pulling sensation in the tongue or face, or flashing lights). The sensations produced at high intensities of stimulation during this testing are experienced as strange, but not painful, and they resolve when the stimulation is reduced or turned off.