The next injury possible as the result of a traumatic injury and after the primary brain injury has occurred, is hydrocephalus. Hydrocephalus is the flow of fluid from the spinal cord and brain into the cavities, or ventricles, of the brain is sometimes blocked or disrupted after a brain injury. When this happens fluid can build up in the brain and cause increased pressure. This condition is called hydrocephalus, and it can be a serious secondary brain injury. Pressure can be relieved through a procedure that involves inserting a needle into the brain cavities, drawing off the fluid, and routing it through a tube into the abdominal cavity.