Anterior Lumbar Interbody Fusion (ALIF)
Frequently Asked Questions
When considering the indications for lumbar spine fusion, lower back pain that lasts for more than six months is the most general indication. The indications for fusing the lower back occur primarily in situations where there is a large deformity, such as:
- Mechanical back pain (usually attributed to disc degeneration)
- Spinal stenosis (narrowing of the spinal canal)
- Spondylolisthesis (slippage of one vertebra on another)
- Patient history
- Physical exam
- X-rays, Magnetic Resonance Image (MRI) or CT scan
- Continue to live with condition
- Physical therapy (exercises and stretching)
- Chiropractic manipulation
- Epidural Steroid Injections (ESIs)
- TENS Units
Purpose of Procedure
The primary purpose of this procedure is to stabilize the spine by restoring the disc height and alignment using metal cages and/or pedicle screws. We fuse the vertebrae together using the patient’s own bone or a genetically engineered substance known as Bone Morphogenetic Protein (BMP). Relieving pressure on the nerves may be combined with the fusion by laminectomy.
Bone for Fusion
There are currently two primary alternative sources for the bone needed for the spinal fusion. Traditionally, some of the patient’s own bone has been harvested from the iliac crest (pelvic bone). This technique produces excellent results for the fusion.
Early in 2003, the FDA approved a genetically engineered bone substitute for use in spinal fusions. Under the brand name, InFUSE, BMP converts stem cells into bone-forming cells and stimulates rapid growth of bone at the targeted site. Using this orthopedic stem cell treatment eliminates the need for harvesting the patient’s own bone and speeds up the fusion process.
Using either form of bone graft can yield a high rate of fusion, but neither is 100 percent guaranteed. BMP tends to give better rates of fusion than other graft materials, including pelvic bone.
What are the cages made of?
Metal cages are usually made of titanium. Newer cages are being made of carbon fiber and special inert synthetic compounds. These do not set off airport screening detectors.
Advantage of Anterior (Front) Approach vs. Posterior (Back) Approach
In the ALIF approach, a three-inch to five-inch incision is made on the left side of the abdomen, and the abdominal muscles are retracted to the side. Since the anterior abdominal muscle in the midline runs vertically, it does not need to be cut and easily retracts to the side. The abdominal contents lay inside a large sack (peritoneum) that can also be retracted, thus allowing the surgeon access to the front of the spine.
The large blood vessels that continue to the legs (aorta and vena cava) lay on top of the spine, so we perform this surgery in conjunction with a vascular surgeon who mobilizes the large blood vessels. After the blood vessels have been moved aside, the disc material is removed and bone graft, or bone graft and anterior interbody cages, is inserted.
The ALIF approach has the advantage that, unlike the PLIF and posterolateral approaches, both the back muscles and nerves remain undisturbed. Another advantage is that placing the bone graft in the front of the spine places it in compression, and bones in compression tend to fuse more readily. This also allows for the removal of the common source of pain, namely the disc.
However, there is also a major risk that is unique to the ALIF approach: the procedure is performed in close proximity to the large blood vessels that go to the legs. Damage to these large blood vessels may result in excessive blood loss. This is a rare complication.
For males, another risk unique to this approach is that approaching the L5-S1 (lumbar segment 5 and sacral segment 1) disc space from the front has a risk of creating a condition known as retrograde ejaculation. This condition causes ejaculation to go up into the bladder instead of out. The sensation of ejaculating is largely the same, but it makes conception more difficult. Fortunately, retrograde ejaculation happens in less than 1% of cases and tends to resolve in 1 – 2 years.
Who will be involved in the procedure?
Surgeon – The orthopedic spine surgeon who you have been seeing in our office will be the primary surgeon, in charge of your surgery.
Assistant Surgeon – Another orthopedic spine surgeon, usually from our office, will assist your orthopedic surgeon with the procedure. This is done to minimize the length of time you are under general anesthesia and to provide the necessary assistance with the actual surgical procedure.
Anesthesiologist – The doctor who actually administers and monitors the anesthesia is a critical part of the surgical team. You will normally meet with the Anesthesiologist during your pre-op appointment at the hospital.
Length of Surgery
One to two hours is typical for one and two levels fused anteriorly.
With most spinal surgeries, patients are up and walking within hours after their procedure. It is no longer necessary nor recommended that you lie in bed for days or weeks after spine surgery. Nurses who are experienced in working with spinal surgery patients will assist you during your first few efforts at getting out of bed and walking.
Your doctor will tell you when it is safe to shower after surgery. Showers are usually allowed 2-3 days after surgery. Soaking in a bathtub is not allowed.
The nursing staff at the hospital will show you how to keep the dressing dry and in place to protect the incision while showering. The wound should not be submerged in water (pool or tub) until it has healed and has been cleared by your doctor. The nurse will change the dressing after your shower, and again later if necessary.
Your surgical incision will be checked during your first post-op appointment. However, should your incision become red and tender, or if drainage should occur prior to your first scheduled post-op visit, you should contact our office for instructions.
Liquids are allowed right after surgery. Solid foods are not started for several days. Your doctor will give you specific instructions.
How much pain should I expect and how is it treated?
Your doctor’s goal is to keep you as comfortable as possible. Almost all strong pain medications are narcotics that tend to make you sleepy and can depress your breathing. We must balance the side effects with our goal to relieve pain. In the hospital, (IV) patient-controlled medications are given the first day. We then switch to oral medications. You will have pain pills for home use as well. We continue home medications as needed with the goal of weaning them as you recover. It is important to tell your doctor of any allergies to medicines and to only use pain medications as directed. Mixing medications can be dangerous. We do not refill pain medications after hours or on weekends. You must ask ahead 1-2 days if you are going to run out of pain pills. Refills of medications are at your doctor’s discretion.
Return to Routine of Normal Daily Living
It normally takes approximately 3 to 6 months for the fusion to occur. During that time, you should avoid strenuous activities that might affect the fusion process.
During the rehabilitation process, it is important to recondition the muscles with exercise, stretching, and aerobic conditioning. Your doctor will give more specific instructions during the course of your post-operative care during your office visits.
Driving is not allowed until after your first post-op visit (usually 7-10 days). Most patients are able to go up and down stairs when they go home from the hospital. Some patients may require additional assistance.
Return to Work
Return to work is determined for each individual patient based upon several factors. The doctor’s goal is to help you return to work as soon as you can do so safely. If you have a light or sedentary job, or if light duty restrictions are available, then return to work could occur in 10-14 days. If you are able to work from home by phone, fax and computer, very early work may be realistic. If your job is very heavy and strenuous, return to work can take several months. Other factors that play a role in your return include your overall physical condition, tolerance of pain, and your need for additional therapy.
Even the best results of surgery do not mean that you will necessarily be able to return to your prior type of job. Some patients are advised to go through job re-education or find a lighter job for future back safety.
Risks and Potential Complications
- Complications from anesthesia
- Continued low back or leg pain
- Fusion may not occur (higher incidence of non-fusion in patients who smoke)
- Hardware (i.e. pedicle screws or cages) may break or come loose
- Nerve damage
- Loss of sexual function
No guarantees can be made as to the success of this procedure.
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