Transforaminal Lumbar Interbody Fusion (TLIF) Animation

This narrated animation about Transforaminal Lumbar Interbody Fusion (TLIF) explains how disc pain may originate and demonstrates TLIF; a type of spinal surgery performed to treat disc disorders and stabilize the spine.

Spine surgeons may recommend TLIF to treat different types of lumbar disorders such as disc bulge or herniation, degenerative disc disease or spondylolisthesis. These low and lower back problems may cause nerve compression (eg, pinched nerves) and/or spinal instability leading to back and/or leg pain. TLIF can help decompress the spine by removing whatever is pressing on nerve roots, such as a herniated disc and then stabilizing that spinal segment. Interbody devices and other types of spinal instrumentation are combined with bone graft to stimulate fusion.
Example of spinal nerve compression, overhead view.Anatomical illustration shows a herniated disc compressing a spinal nerve within the foramen (neuroforamen). Photo Source:

Transforaminal Lumber Interbody Fusion Terminology Explained

What does transforaminal mean?
Transforaminal refers to going across or through the foramen. Foramen refers to the nerve passageways created by an intervertebral disc that separates its upper and lower vertebral bodies. Another name for these nerve passageways is neuroforamen.

What is the meaning of lumbar?
The term lumbar refers to the five vertebrae that make up the low or lower back. The term originated about 1800 years ago, when a Greek physician named Claudius Galen sketched out his dissections of the spines of animals, including two humans. Galen was the first to roughly name different regions of a spine. “Cervical, dorsal and lumbar,” he scribbled beside his drawings. Today, modern physicians divide the spinal column into five regions—cervical (neck), thoracic (mid back), lumbar, sacral (sacrum, back of pelvis) and coccygeal (tailbone), but Galen’s term “lumbar” stuck from the second century and is the second word in a TLIF procedure.

What is the meaning of interbody in a TLIF procedure?
Interbody refers to a type of medical device or spinal instrumentation—often called an interbody device or interbody cage. It is implanted into the empty disc space after the damaged disc is surgically removed (discectomy).

Interbody devices are designed and made from strong materials to withstand the body’s pressures and forces during rest and movement, and porous to allow new bone growth into and around the device.

Some interbody devices are made of a metal like titanium and/or a special polymer with a name that sounds like the scientist might be stuttering called, “polyetheretherketone,” or PEEK. Scientists are always working on new ideas for the best material with which to craft the interbody device and thinking of what coatings could be applied to promote bone growth. Because the interbody device is often hollow and porous, it is sometimes called an interbody cage.

What is fusion and its role in TLIF?
Fusion is a healing process whereby two (or more) bones (eg, vertebral bodies) grow together into a solid mass. Fusion is also called spinal fusion, involves use of bone graft material (eg, autograft) with spinal instrumentation (eg, interbody devices) to stimulate new bone growth. It can take upwards of three months for fusion to heal and permanently fuse bone together. Sometimes fusion doesn’t heal properly or completely causing what is called a nonunion, pseudoarthrosis or failed fusion.

The goal of spinal fusion is to stabilize and stop movement of the spine at the levels operated on, such as L4-L5 (fourth and fifth lumbar levels). Spinal instrumentation, such as interbody devices, rods and screws provide immediately stabilization of the operative levels while fusion heals. Spinal fusion helps to eliminate articulation or movement, even micro movement of two or more vertebrae that can cause back and/or leg pain.

How is transforaminal lumbar interbody fusion surgery performed?

TLIFs can be performed as a traditional “open” surgery or through minimally invasive spine surgery (MiTLIF) techniques using general anesthesia. The spine surgeon accesses the particular level of the lumbar spine from the back (posterior) through one or more incisions. The size of the incision and the way soft tissues (eg, muscles) are moved to access the spine depend on whether the procedure is performed open or MiTLIF.

TLIF involves removing the intervertebral disc (discectomy) as well as bone or tissue compressing spinal nerves (decompression such as laminectomy) in the foramen. It may be necessary to remove part of the facet joints (facetectomy) for nerve decompression and access to the disc.

After the intervertebral disc is removed, the disc space is prepared for insertion of two or more interbody devices or interbody cases. Bone graft is strategically packed into and around the devices and disc space. Pedicle screws and rods are affixed to stabilize the operative levels.

Bone Graft Options

Autograft, allograft and bone morphogenic protein (BMP) are three types of bone graft materials. Autograft is the patient’s own bone that is taken from the iliac crest of a hip bone. Obtaining autograft requires a separate surgical procedure. Allograft is donor bone acquired from a tissue bank. BMP is a biological material containing factors that help stimulate new bone growth.

Updated on: 09/03/19
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