Spinal fusion is a surgical procedure that involves joining or fusion of two or more vertebrae together. To facilitate the fusion, bone grafting is required in fusion surgery which involves taking a small part of the bone from the patient’s pelvic bone (known as autograft) or from a donor (called allograft) and placing it between the vertebrae to allow them to fuse together. Some of the common spinal disorders such as spondylolisthesis, severe disc degeneration, spinal fusion or scoliosis can be treated by spinal fusion surgery. Fusion surgery is generally recommended when non-operative treatments have failed.
There are three common types of fusion surgeries: PLIF, ALIF and TLIF.
PLIF – Also known as posterior lumbar inter-body fusion is performed to treat degenerative lumbar problems like scoliosis or spondylolisthesis. This procedure can be performed as an open or minimally invasive surgical procedure in which surgeon accesses the spine from the middle of the back. The PLIF procedure involves a laminectomy and removals of the facet joints to access the nerves roots, disc and spinal canal.
Before the surgery, doctor may perform several tests such as MRI or CAT scans to determine the size of implant that patient may require. He/she will then prepare the disc space and will make an incision depending on the number of levels to be fused on the patient’s back and move aside the spinal muscles to access the vertebral disc. Lamina will be removed carefully to reach the nerve roots. Surgeon will then trim the facet joints that lie directly over the nerve roots to create more room for the nerve roots. He/she will then remove the diseased disc and nearby tissue and prepares bone surfaces of another vertebrae for fusion. Then surgeon will place the implants in position and when the disc space is prepared, he will insert bone graft or allograft to stimulate fusion between the vertebrae. Some additional instruments such as rods or screws may also be used to further stabilize the spine.
PLIF has many benefits e.g. it can provide anterior fusion of the disc space without need of second incision and some disadvantages e.g. not as much of the disc space can be removed with PILF procedure or there is a potential risk that inserting a cage through PILF will allow it to retro pulse back into the canal and create neural compression. There are more chances of failure in case of patients who smoke or are obese, patients who had multiple level fusion surgery or patients who have been treated with radiation for cancer. But if the patient’s symptoms get better and joints are stable then he/she may not need another spine fusion surgery.
TLIF – Transforminal lumbar interbody fusion or TLIF is similar to PLIF procedure and has gained popularity as a treatment for spinal (lumbar) conditions. This technique involves accesses the spine just as performed in PLIF but more side of the spinal canal through the incision made along the middle line in the patient’s back. This can greatly reduces the surgical dissection of the muscle and minimizes the nerve manipulation required to access the bone, discs and nerves. Due to fewer traumas to the spine, safety of nerves and minimal access with the help of endoscopic techniques, this approach is more preferred among the patients with spinal problems. During the surgery, surgeon will remove the disc material from the spine and replace it with bone graft along with cages, screws or rods if required are inserted into the disc space. These instruments help in facilitating the fusion along with adding strength and stability to the spine.
There are several advantages of TLIF such as enhanced bone fusion due to the bone graft that is placed both along the gutters of the spine posteriorly but also in the disc space, reduced injury and scarring around the nerve roots as compared to PLIF procedure etc. Some of the potential risks of this procedure are reaction to anesthesia, infection, and blood loss, injury to nerves or lack of solid fusion.
ALIF - ALIF also known as anterior lumbar inter-body fusion is similar to PLIF, but is performed from the front (anterior) side of the body, to remove a lumbar disc and fuse the spine through an incision made in the lower abdominal area. A mini open ALIF is more preferred procedure as it preserves the muscles and incisions are smaller. This approach maintains abdominal muscle strength and function. After accessing the vertebrae, disc material will be removed after retracting the abdominal muscles and blood vessels. Surgeon will then inserts bone graft to stabilize the spine and stimulate the fusion.
Recovery from ALIF, PLIF OR TLIF may depend on many factors such as patient’s overall health conditions, spine problem etc. patient may require to stay in the hospital for 2-3 days depending on the their condition and doctor will recommend some pain medications, physical therapy, healthy diet to fasten the recovery process.