Spinal fusion (such as a TLIF) is a surgical technique to stabilize the spinal vertebra and the disc or shock absorber between the vertebra. Lumbar fusion surgery is designed to create solid bone between the adjoining vertebra, eliminating any movement between the bones. The goal of the surgery is to reduce pain and nerve irritation.
Spinal fusion may be recommended for conditions such as spondylolisthesis, degenerative disc disease or recurrent disc herniations. Surgeons perform lumbar fusion using several techniques. This article describes the transforaminal lumbar interbody fusion (TLIF) fusion technique.
Procedure for Spine Fusion Using TLIF Technique
TLIF back surgery is done through the posterior (back) part of the spine.
- Surgical hardware is applied to the spine to help enhance the fusion rate. Pedicle screws and rods are attached to the back of the vertebra and an interbody fusion spacer is inserted into the disc space from one side of the spine.
- Bone graft is placed into the interbody space and alongside the back of the vertebra to be fused. Bone graft is obtained from the patient’s pelvis, although bone graft substitutes are also sometimes used.
As the bone graft heals, it fuses the vertebra above and below and forms one long bone.
TLIF fuses the anterior (front) and posterior (back) columns of the spine through a single posterior approach.
- The anterior portion of the spine is stabilized by the bone graft and interbody spacer.
- The posterior column is locked in place with pedicle screws, rods, and bone graft.
Benefits of TLIF Back Surgery Technique
TLIF procedure has several theoretical advantages over some other forms of lumbar fusion:
- Bone fusion is enhanced because bone graft is placed both along the gutters of the spine posteriorly but also in the disc space.
- A spacer is inserted into the disc space helping to restore normal height and opening up nerve foramina to take pressure off the nerve roots.
- A TLIF procedure allows the surgeon to insert bone graft and spacer into the disc space from a unilateral approach laterally without having to forcefully retract the nerve roots as much, which may reduce injury and scarring around the nerve roots when compared to a PLIF procedure.
As with all forms of lumbar spine fusion, prior to TLIF surgery medical clearance is obtained. Smoking should be stopped. Patients may require pre-donation of blood to be used at the time of surgery.
How Is A TLIF Performed?
A general anaesthetic will be administered to put you to sleep. A breathing tube (‘endotracheal tube’) will be inserted and intravenous antibiotics and steroids injected (to prevent infection and post-operative nausea). Calf compression devices will be used throughout surgery to minimise the risk of developing blood clots in your legs. A catheter will be inserted into your bladder to prevent bladder distension during surgery and to monitor urine output. You will be placed face-down on the operating table on a special spinal frame.
Your skin will be cleaned with antiseptic solution and some local anaesthetic will be injected.
The skin incision is usually about 6-10cm in the middle of you lower back. It is vertical.
The plane between your back muscles on each side of the spine is then followed down, and screws are inserted into the pedicles at the appropriate levels.
The facet joint on one side is removed using a high-speed drill, and the nerve roots are identified and decompressed (this is known as a ‘rhizolysis’).
A microdiscectomy is performed (see picture). This is done by first cutting the outer annulus fibrosis (fibrous ring around the disc) and removing the nucleus pulposus (the soft inner core of the disc). Disc removal is performed using a combination of special instruments.
The boundaries of the disc space (the vertebral end-plates) are then carefully prepared to facilitate fusion. Some bone from the facet joint is mixed with tricalcium phosphate and bone morphogenetic proteins, and this is packed into the empty disc space.
An interbody cage (made of carbon fibre, PEEK, or trabecular metal) is filled with bone and inserted into the disc space.
A small piece of fat is laid over the nerve roots to minimise scarring.
Further bone is laid down over the laminae, as well as the opposite facet joint and transverse processes (posterior and posterolateral fusion).
The screws are then connected by rods and, if a significant slip (spondylolisthesis) is present, this may be partially reduced.
What Happens Immediately After Surgery?
It is usual to feel some pain after surgery, especially at the incision site. Pain medications are usually given to help control the pain. While tingling sensations or numbness is common, and should lessen over time, they should be reported to your neurosurgeon.
Most patients are up and moving around within several hours of surgery. This is encouraged in order to keep circulation normal and avoid blood clot formation in the legs.
You will be able to drink after 4 hours, and should be able to eat a small amount later in the day.
A CT scan will be performed the next day to check the position of the screws and cage.
You will be discharged home when you are comfortable, usually after a short period of inpatient rehabilitation.
What Happens After Discharge?
You will need to wear a special brace for 3 months after surgery whilst you are sitting, standing or walking. You will need to take it easy for 8 weeks, but should walk for at least an hour every day. You should avoid sitting for more than 15-20 minutes continuously during this time.
At 6-8 weeks it is likely that you will be able to return to work on “light duties” and to drive a motor vehicle on short trips. This, and the step-wise progression in your physical activities, will be determined on an individual basis.
Bear in mind that the amount of time it takes to return to normal activities is different for every patient. Discomfort should decrease a little each day. Increases in energy and activity are signs that your post-operative recovery is progressing well. Maintaining a positive attitude, a healthy and well-balanced diet, and ensuring plenty of rest are excellent ways to speed up your recovery.
Signs of infection such as swelling, redness or discharge from the incision, and fever should be brought to the surgeon’s attention immediately.
You will be reviewed after 6-8 weeks by your neurosurgeon. Until then, you should not lift objects weighing more than 2kg, and should not engage in bending or twisting movements.
The results of fusion surgery are not as good in patients who smoke or are very overweight. It is therefore important that you give up smoking permanently before your surgery and try to lose as much weight as possible.
You should continue wearing your TED stockings for a couple of weeks after surgery.