A-B | C-D | E-G | H-K | L-M | N-P | R-U | V-Z


H

HEAD TRAUMA – See Traumatic Brain Injury.

HEMATOMA - A localized collection of blood, usually clotted, caused by bleeding from a ruptured blood vessel.

HEMORRHAGE – A sudden and dramatic loss of blood, either internally or externally, from damaged blood vessels.

HEMORRHAGIC STROKE - A form of stroke that occurs when a blood vessel in the brain ruptures or bleeds.

HERNIATED DISC (SLIPPED OR RUPTURED DISC) – The bones (vertebrae) that form the spine are cushioned by small discs, which act as shock absorbers for the spine.  They are round donut shapes with a tough outer layer (annulus) that surrounds a jellylike material (nucleus).  Thick ligaments attached to the vertebrae hold the pulpy disc material in place.  A herniated disc is a fragment of the disc nucleus which is pushed into the spinal canal through a tear or rupture.  Discs that herniated are usually in an early stage or degeneration.  The spinal canal has limited space which is inadequate for the spinal nerve and the displaced herniated disc fragment.  Due to this displacement, the disc presses on spinal nerves, often producing pain, which may be severe.  Herniated discs are more common in the lower back (lumbar spine), but also occur in the neck (cervical spine).

HNP (Herniated Nucleus Pulpous) – See Herniated Disc.

HYDROCEPHALUS - A condition in which excess cerebrospinal fluid accumulates in the brain. It is often treated with the surgical placement of a shunt to divert the fluid from the brain.

HYPERTENSION - High blood pressure.

HYPOTHALAMUS - A collection of specialized nerve cells at the base of the brain, which controls the anterior and posterior pituitary secretions. They are involved in other basic regulatory functions such as temperature control and attention.

I

IMAGE-GUIDED STEREOTACTIC SURGERY – Also called Frameless Stereotactic Surgery. A minimally invasive surgical technique that uses images to guide the surgeon to a target within the cranium - very helpful for the accurate approach and removal of large brain tumors.  Using an external, three-dimensional frame of reference (for instance, a combination of digitizing cameras, motion tracking software, fiber optic sensing technology and infrared emitters), the system correlates live radiographic images to determine tumor position. Rather than an invasive metal head or body frame, the patient is fitted with a custom mesh garment. Fiducial markers are taped to the scalp before the brain is imaged, and then the orientation of these markers is used to register the computer containing the brain images. The apparatus senses the position of the surgeon's instruments in space and indicates the position on the image displayed on the computer monitor in real time, as the operation proceeds. Thus, throughout the procedure, the surgeon is continuously monitoring the target and readjusting calibrations to assure that they are locked on the tumor. The main advantages with image-guided stereotactic surgery include: more precision in approach and navigation, limited surgical exposure, greater safety, and more complete tumor removal.

INFLAMMATION - A normal reaction to injury or disease, which results in swelling, pain, and stiffness.

INTERBODY FUSION - A bone graft in the space between discs for the purpose of fusing two vertebral segments.

INTRACRANIAL PRESSURE (ICP) - The overall pressure inside the skull. ICP measures CSF and the brain’s blood supply in closed intracranial space. Most commonly due to head injury, a sudden or large increase in ICP can be life-threatening.

INVASIVE PROCEDURE - An operative procedure, major or minor, usually by cutting or puncturing the skin or by inserting instruments into the body.

IPD (INTRASPINOUS PROCESS DECOMPRESSION) – A minimally invasive surgical procedure for the treatment of spinal cord compression. Under local anesthesia, a titanium implant known as X-Stop® is fitted between the posterior parts of the vertebral body, giving the spinal cord and nerve roots more room. The procedure is not a fusion and preserves most structure and movement.

ISCHEMIA - The inadequate circulation of blood generally due to a blockage of an artery.

ISCHEMIC STROKE – The most common type of stroke (occurs in approximately 85 – 90% of stroke incidences) in which a blood vessel becomes occluded and the blood supply to part of the brain is totally or partially blocked.

J

JOINT - A point of articulation between two or more bones that allows motion.

JUGULAR VEIN - The major vein on each side of the neck, which drains blood from the head towards the heart.

KYPHOSIS - A curve in the spine that points to the back of the body.