Posterior Lumbar Fusion
Posterior lumbar fusion, also known as arthrodesis, is a surgical procedure performed to join two or more of the lumbar vertebrae (the small bones of the lower back) into one solid bone. This operation is designed to stop mechanical pain, the pain associated with the movement of the affected bones that results in inflammation of the discs and joints. During this surgery, a bone graft is inserted along the side of the vertebrae which will eventually help the bones grow together. The procedure is called a posterior fusion because the surgeon works on the back of the spine.
Reasons For Posterior Lumbar Fusion
Posterior lumbar fusion is commonly performed to treat a variety of spinal conditions affecting the lower back, including:
- Spinal fractures
- Degenerative disc disease
- Radicular pain (down the buttock and thigh)
Other surgical procedures are frequently performed along with lumbar fusion, such as removing bone spurs or repairing herniated discs.
The Posterior Lumbar Fusion Procedure
During the procedure, performed under general anesthesia, the patient is usually face down on a special operating table. This position not only provides the surgeon with room to operate and increases comfort for the patient, but also lessens the patient’s blood loss.
An incision is made in the middle of the lower back to expose the spinal column, and part of the lamina, the bony covering of the spinal canal, is removed. The surgeon also removes any disc fragments or bone spurs impinging on the nerves, and prepares the patient for the fusion by shaving off a layer of bone from the back of the affected vertebrae. This resulting cut surface is receptive to the bone graft that will be attached.
Because the primary goal of a posterior lumbar fusion is to eliminate the mechanical pain and inflammation associated with vertebral movement, the operation basically consists of a type of welding, in which the bone graft, taken either from the patient’s own hip (autograft), harvested from a cadaver (allograft) or manufactured (synthetic), is used to stimulate bone growth. Most often, the graft is fixed in place using a combination of screws, rods and plates to keep the vertebrae from moving. Held in place this way, the tissues have a higher success rate of growing together completely and permanently.
Recovery From Posterior Lumber Fusion
Recovery from this surgery takes from 1 to 3 months during which the patient normally undergoes physical rehabilitation and must avoid heavy lifting, bending and twisting.
Posterior Lumbar Interbody Fusion
Posterior lumbar interbody fusion (PLIF) is a spinal surgical procedure performed to provide relief from debilitating pain in the lumbar (lower) region of the spine. PLIF is performed by through the patient’s back. A posterior approach can be advantageous since it avoids interfering with the many organs and major blood vessels present in the abdominal region. Also, a posterior approach brings the surgeon to the affected site more quickly. Interbody fusion involves removing an interverterbal disc, replacing it with a bone spacer and fusing the two vertebrae on either side.
PLIF is a successful treatment for a number of lower back problems, such as spondylothesis and disc space collapse, also known as disc degeneration, that have not responded to more conservative therapies. Prior to the procedure, detailed images of the spine are produced using MRI and CT scans. In addition to confirming the diagnosis, these images allow the surgeon to pinpoint the exact location of the problem and to determine which implant device is most appropriate for use in the repair.
The PLIF Procedure
The PLIF procedure is performed with the patient under general anesthesia, positioned face down on the operating table. The treatment site is cleansed with an antiseptic and the surgeon makes a three-to six-inch incision in the midline of the back near the affected portion of the spine. Tools are used to separate and retract the muscles. An imaging device will ensure that the precise vertebrae are targeted. Next, the lamina, or outer covering of the spinal cord, is removed and any excess bone is trimmed back to present an unobstructed view of the nerve roots. The injured disc, bone spurs and any debris are then removed. This recreates a space for the nerves that have been compressed, relieving pain and symptoms in the lower back and legs.
To fill the space that has been created, a bone graft or bone morphogenetic proteins are placed in the open disc area and instrumentation is affixed as needed to maintain spinal stability. The hardware used often includes two spacers containing the graft material, with one positioned on each side of the interbody space. The surgeon carefully inserts the spacers, avoiding the spinal cord and adjacent nerves. In addition, metal plates, rods and screws will be attached to the vertebrae to hold the spinal bones in place as they grow together.
Bone morphogenetic protein (BMP) is an FDA-approved treatment used in conjunction with spinal fusion surgery to stimulate bone growth within the treated area and achieve optimal results without the need for a bone graft. Bone grafts taken from another part of the patient’s own body or obtained from donor bone, however, are also highly successful. Once the operation is complete, imaging is used once again to confirm the placement of instrumentation. Finally, the incision is closed with sutures or surgical staples. PLIF procedures may vary in length, generally lasting between 3 and 6 hours, depending on the extent of the spinal damage.
Recovery From A PLIF Procedure
After undergoing a PLIF procedure, a patient typically remains in the hospital for 3 to 5 days. A physical therapy regimen is started soon after to assist the patient in regaining strength and mobility. Certain activities are restricted during the recovery period, including heavy lifting, twisting the midsection,and bending at the waist. Many patients can return to work 2 to3 weeks after the procedure. After 3 months, patients can resume more rigorous activities, including some sports. The duration of a full recovery depends on the number of vertebrae that have been fused during surgery and the patient’s individual healing process.
Risks Of A PLIF Procedure
While PLIF is considered a safe procedure, like any spinal surgery it carries some risks. While uncommon, the most frequent complication is nonunion, which means the bones do not fuse properly. This is more likely to occur in those who smoke, are obese, have previously undergone a spinal surgery or have undergone radiation treatments. There is also the minor risk that the patient’s pain will persist after surgery. Other risks of PLIF, or of any surgical procedure, include the possibility of infection, excessive bleeding, blood clot and adverse reaction to anesthesia or medication.
Anterior Lumbar Interbody Fusion
Anterior lumbar interbody fusion (ALIF) is a surgical procedure performed to alleviate persistent lumbar pain, or pain in the lower region of the back. Currently one of the most frequently used spinal fusion techniques, ALIF is performed from the anterior of the spine through the abdomen. Interbody fusion refers to the removal of an intervertebral disc, which is replaced with a bone spacer during the fusion process. This method of anterior incision is chosen when the targeted area of the spine is closer to the front of the body or when the level of instability present is not too great. A major advantage of anterior entry is that a larger implant can be incorporated into the procedure.
Reasons For ALIF
ALIF is performed to treat nerve compression and its associated pain. Such compression of spinal nerves may occur as a result of:
- Disc degeneration
- Abnormal curvatures of scoliosis or kyphosis
- Fracture of one or more vertebrae
- Spondylolisthesis, slippage of one vertebra over another
- Spinal stenosis
- Spinal instability
Patients with persistent low back pain, which often radiates down the leg, may be candidates for ALIF if more conservative treatments, such as rest, non-steroidal anti-inflammatories (NSAIDs), physical therapy and corticosteroid injections, have not been effective in relieving their symptoms.
The ALIF Procedure
The ALIF procedure is performed under general anesthesia with the patient lying face up on an operating table. The surgeon makes an incision on the side of the abdomen near the affected area. The muscles of the back and the nerves do not need to be moved from this approach. The injured disc and any bone spurs or other debris are removed. A bone graft or some bone morphogenetic protein (BMP), an FDA-approved substance that helps to stimulate bone growth, is then attached to connect the affected discs. Any necessary devices to ensure spinal stability as the vertebrae fuse are also implanted.
BMP, discovered in the 1960s, is a protein extract found naturally in the body which can also be created artificially. Its use represents an advancement over previous surgeries, since in assists bone fusion and often eliminates the need for either extracting a bone graft from the patient or using a donor bone graft.
Recovery From ALIF
Patients usually have a smooth recovery from ALIF. After the procedure, they normally remain in the hospital for 3 to 5 days and are able to resume their activities after 6 to 8 weeks. Patients are advised to avoid bending and stretching for 8 weeks and may be restricted from strenuous exercise for a somewhat longer period, depending on their particular circumstances. Patients have to refrain from driving for as long as they require prescribed pain medication. ALIF carries the same risks as other surgical procedures, including risks of excessive bleeding, damage to adjacent tissue, breathing difficulties and adverse reactions to anesthesia or medications.