One of the most common surgical procedures is a discectomy, the removal of a herniated disk to relieve pressure on a nerve root. The first step is to remove a portion of the lamina of the vertebra. The lamina is the portion of the vertebra that forms the roof over the spinal nerves. Removing a portion of the lamina creates a window into the spine. The nerves are then pulled to the side so that the herniated disk can be seen. Small instruments are then used to remove the herniated disk material. Most of the nucleus pulposus is removed to prevent the disk from herniating again. Once the disk material is removed, the nerves are free of pressure and irritation. The lamina and the area of the disk that is removed fill with scar tissue very rapidly.