Glossary

Anterior

This means at the front of the body such as “an anterior approach”, which would mean an approach through the front of the body ie the belly (abdomen)

Anterior interbody cages

Are devices that are made to be inserted into the lumbar disc space through an anterior (from the front) approach. They can be made of allograft bone, titanium, or carbon/PEEK (radiolucent cages).

Cervical

This is the “neck” part of the spine

Degenerative

This is a term used to describe the changes in a body part caused by age, activity or genetics. In other words, the part is wearing or worn out due to overuse, repetitive use over a long time, or not being of good quality to start with

Facet Joints

These are the small synovial joints of the back that are at the back of the back (as opposed to the discs at the front of the back). They are the same sort of joint as knees and hips and so wear down just like their bigger brothers as well. This causes true arthritis and pain particularly on extending the back, which is an activity that compresses the facet joints.

Fusion

The role of spine fusion instrumentation is to provide additional spinal stability while helping the fusion set up. Various forms of instrumentation (medical devices) have been developed with the goal of improving the rates of successful spinal fusion. Because bone tends to fuse more effectively in an environment where there is little motion, instrumentation helps the fusion set up by limiting the motion at the fused segment.

There are five primary types of spine surgery instrumentation: anterior screws/plates (for neck and low back), pedicle/lateral mass screws (for neck and low back), anterior interbody cages (for neck and low back), posterior lumbar cages, and the dynamic implants (disc replacements, interspinous devices and dynamic stabilisation systems). Obviously the latter is not involved in fusion.

In the posterolateral gutter fusion, use of pedicle screws has improved spinal fusion rates from approximately 60% to 90%. Many surgeons also believe that pedicle screws enhance patient recovery because they provide immediate stability for the spine and allow early mobilization for the patient

Graft

In the past, the patient's own bone had been used (autologous bone). This required a large bone graft to be taken from the patient's iliac crest, and had a fairly high complication rate (such as postoperative chronic pain, infection, pelvic fracture). Also, this bone is not all that strong and required supplementation with posterior instrumentation. It is not as strong or supportive as allograft bone

Herniated Disc

A spinal disc herniation is caused by a tear in the outer, fibrous ring of an intervertebral disc allowing the soft, central portion to bulge out.

Lordosis

This is a term used to describe a normal curve seen in the neck and low back

Lumbar

This is the “low back” part of the spine.

Osteoporosis

In osteoporosis the bone mineral density is reduced causing bones to become porous and more susceptible to fractures

Pedicle screws

Provide a means of gripping onto a vertebral segment and limiting its motion. The pedicle screw, which is sometimes used as an adjunct to spinal fusion surgery, provides a means of gripping a spinal segment. The screws themselves do not fixate the spinal segment, but act as firm anchor points that can then be connected with a rod. The screws are placed at two or three consecutive spine segments (e.g. lumbar segment 4 and 5) and then a short rod is used to connect the screws. This construct prevents motion at the segments that are being fused.

After the bone graft grows, the screws and rods are no longer needed for stability and may be safely removed with a subsequent back surgery. However, most surgeons do not recommend removal unless the pedicle screws cause discomfort for the patient (5% to 10% of cases).

While there was a rod and screw breakage rate of approximately 10% in the 1980's, with modern pedicle screws the breakage rate has now been reduced to about one in 1,000.

An analysis of 2,500 patients by 350 physicians conducted by the North American Spine Society found that the complication rate with using pedicle screws in spinal fusion surgery is low. There is about a one in 1,000 chance of nerve root damage, and a 2% to 3% chance of infection.

Posterior

This means at the back of the body such as “a posterior approach”, which would mean an approach through the back of the body ie the muscles of the back

Posterior lumbar cages

Are also made to be inserted into the lumbar disc space, but are modified to be inserted through a posterior (from the back) approach. They can be made out of the same materials as an anterior cage

Scoliosis

This is an abnormal curvature of the spine, generally associated with a twisting of the spine. It is seen in children as well as adults although the cause in adults is mainly degeneration (wear and tear) whereas in children the cause is often not known.

Spinal Stenosis

Spinal stenosis occurs when the spinal canal narrows and compresses the spinal cord and nerves

Spondylitis

Spondylitis is an inflammation of a vertebra. Inflammatory arthritis of the spine.

Spondylolisthesis (Slipped disc)

Spondylolisthesis is the movement of one vertebrae in either the anterior or posterior direction due to instability

Spondylolysis

Spondylolysis is a defect in the pars interarticularis of a vertebra.

Spondylosis (Degenerative Disc Disease)

Spondylosis is degenerative arthritis, osteoarthritis, of the spinal vertebra and related tissue

Thoracic

This is the “chest/rib cage” part of the spine