A transforaminal lumbar interbody fusion, or TLIF (pronounced “tee-liff”) is performed to remove and replace a worn out, or degenerated disc with the goal of growing together or fusing the spine. Implants are inserted to help stabilize the spine. Using a less or minimally invasive surgical technique, this procedure can be done with a smaller incision than traditional open spinal surgeries that use a larger incision and may help avoid disrupting or damaging the low back muscles.
For a single level TLIF procedure, which involves one intervertebral disc and the spinal bones, or vertebrae, above and below it, an incision is made on the side of the lower back where the diseased disc is located, and two small incisions are made on the opposite side. A device, called a fluoroscope, that projects live x-ray images onto a screen is typically used to help pinpoint the exact positions on the spine where the instruments will go. Next, thin metal wires designed to help guide the instruments are inserted into each incision through tissues and muscle to the bones of the spine where the retractor will dock (on the side of the diseased disc) and to the bones where screws will be inserted (on the opposite side). Special instruments (dilators) are guided down the wires to separate muscle fibers and provide access to the underlying spinal bones. After the initial dilators are docked on the back of the spine, larger dilators are added, gradually increasing the diameter of the incision area to allow enough room for the instruments to pass.
With the dilators in place, a sharp instrument called an awl is inserted into the bones connecting the back of the vertebrae to the vertebral bodies in the front of the spine. These bones are called pedicles, and the instrumentation placed into them are called pedicle screws. These screws may be placed into the vertebrae above and below the diseased disc on both side of the spine. For a single level TLIF, this means four screws are placed, two on each side. Next, a device called a retractor is inserted to allow your surgeon to expand the surgical field. It is connected to the pedicle screws on the side of the spine where the diseased intervertebral disc can best be reached. A lighting component is attached to illuminate the surgical field. Typically, the retractor can then be opened further, helping to hold muscle and soft tissue out of the way. With the retractor and screws in place, your surgeon can now move on to the discectomy, or intervertebral disc removal.
Through the opening in the retractor, your surgeon is now able to remove a portion of the back of the vertebra in order to allow access to the disc. A grasping instrument is used to remove most of the intervertebral disc. Removing the facet joints and disc is intended to help relieve pressure on the spinal nerves. A single implant, which can be either a piece of donor bone or an implant made of metal or plastic and filled with natural bone material, is placed in the disc space through the exposed area where the facet joint was removed. The implant is intended to help provide stability to the spine as fusion (growing together) occurs between the vertebrae above and below it. If successful, spinal fusion takes place in the weeks and months following surgery.
To help provide stability to the spine while the fusion occurs, rods are inserted between the upper and lower screws on both sides to connect them. A device called a compressor can be used to squeeze the upper and lower vertebral bodies together, which can help allow for a tight fit of the implants in the disc space. This pressure, called “compression,” is intended to aid in the spinal fusion process. Small screws called blockers are then inserted to tighten the screws and rods in the compressed position. If successful, spinal fusion takes place in the weeks and months following surgery and can be assessed by your surgeon using imaging studies (e.g., x-rays) taken during follow up visits.
Your surgeon will close the incision and dress it with a wound covering at the conclusion of the surgery. Some patients require a brace for a short period of time after surgery. A minimally invasive surgical, or “MIS” approach can be performed with potentially less operative blood loss and shorter hospitalizations than traditional open surgery. As with any surgery, spinal surgery carries certain risks. Your surgeon will explain all the possible complications of the surgery, as well as side effects.
