TRANSFORAMINAL LUMBAR INTERBODY FUSION
Interbody fusion involves placement of fusion implants and bone graft into the area between two vertebral bodies and is an effective method for achieving fusion. The intervertebral implant may be made from a variety of materials including metal, plastic, or bone. Bone graft and bone healing protein may be placed within the implant and within the interbody space to encourage bony healing. The implant helps by separating and holding the two vertebrae apart. This increases the opening around the nerve roots at that level, relieving pressure on the nerves. The intervertebral implants can also be used to correct spinal deformity and restore proper alignment. Intervertebral implants can be placed from the front, side or back of the spine. The location of the surgery is dependent on the specific anatomy of each patient, as well as the location and amount of pressure that may be occurring around the nerves in the spinal canal. The decision is based on many factors including the patient’s anatomy, location of the levels that need to be fixed, degree of spinal instability, and prior abdominal surgery.
HOW DOES TLIF WORK?
The patient is brought to an operating room and placed under general anesthesia with a breathing tube for the duration of surgery, usually about 3-4 hours for a one-level procedure. X-ray is used to plan two small (about 2 inches long) lower back incisions – one on each side of midline – through which the surgery is performed. If intraoperative CT scanner and 3-D navigation are used, a small incision is also made over the pelvis in order to attach the navigation frame.
Without cutting through the muscles, a series of dilators are used to separate muscle fibers and provide access to the spine. A retractor is placed over the dilators and provides a working channel to perform the surgery. A microscope is then used to provide a close-up view during the procedure.
Bone spurs and overgrown ligament are removed in order to create more room for nerves in the spinal canal. Most of the disc between the vertebrae is then removed to create space for fusion between the bones. A synthetic spacer packed with patient’s own bone chips and synthetic material is then inserted between the vertebrae. The spacer provides support to the spine and aids bone fusion. Additional synthetic material is placed around the spacer to stimulate bone growth.
Titanium screws are inserted into the vertebrae above and below the spacer and connected together with titanium rods. This provides support to the spine while the bones fuse together over time. The screws and rods do not need to be removed and do not set off the metal detector at the airport.
The incisions are then closed with sutures that stay under the skin and dissolve over time, so no suture removal is necessary. Sterile dressings are placed that stay on for two days. If the surgery involves 2 or more levels or if the patient has risk factors for fusion not taking, a lumbar brace and/or a bone growth stimulator is worn for 6 weeks after surgery; otherwise, no brace is necessary.