Anterior Lumbar Interbody Fusion
ALIF is a surgical fusion of the lower spine where the spine is approached from the front i.e. through the abdomen. The intervertebral disc is removed and replaced by bone graft and a cage (spacer). The aim of the surgery is to prevent movement between the involved vertebrae and realign the spinal column so as to reduce the back pain and relieve the compression on the nerves.
About the surgery
Lumbar spine with discs
- Anaesthesia: The surgery is performed under a general anaesthetic, with the patient lying on the back.
- Procedure: A 7-10cm incision is made in the abdomen and the abdominal muscles (rectus abdominis) are retracted to the side. The abdominal contents (intestines) that lie inside a large sack (peritoneum) are retracted to allow access to the front of the spine. The large blood vessels that continue to the legs (aorta and vena cava) lie in front of the spine and have to be moved out of the way to access the spine. After the blood vessels have been moved aside, the intervertebral disc is excised and the resultant space is filled with a cage (made from a plastic substance called PEEK) filled with bone graft. A drain tube may be placed in the wound to remove the blood that collects at the surgical site. The incision is closed with dissolvable sutures.
After surgery
Arteries in front
of the spine
- In the recovery room: Following surgery, you will be transferred to the recovery room and may feel some pain at the operated site when you wake up. You will be given pain medications, antibiotics, intravenous fluids to keep you hydrated and a urinary catheter will empty your bladder. When you are comfortable you will be transferred to your room.
- In the ward: Since the abdomen was opened during surgery, you will be advised not to eat or drink anything for the first 12 -24 hours. You will then be commenced on a clear fluid diet and gradually progress to a light diet. Medications will be provided to reduce your pain after surgery and at home for the first 1-2 weeks. However, if you have excessive pain while you are in the hospital, the attending nurses should be informed. The day after surgery, the drain tube and the urinary catheter will be removed and you will be encouraged to walk wearing a brace to support your spine. You will stay in the hospital for approximately 3-5 days and your surgeon will decide when you can go home.
- At home: Once you are at home, it is important to stay active and take short walks at regular intervals to help reduce pain and hasten your recovery. Gradually increase the distance you walk each day but avoid strenuous activities, heavy lifting and twisting. You may require some help with chores and errands for the first few weeks and it is advisable to have someone to help with these activities.
Risks and potential complications
One level anterior
umbar fusion - front view
All surgical procedures are associated with a risk of complications and all risks should be discussed with your surgeon. Allergic reaction to the anaesthetic or other medications and unforeseen complications such as pneumonia, stroke or heart attack are not caused by the surgical treatment and although rare it may have serious consequences. Please let your surgeon and anaesthetist know if you are allergic to medications and if you have any medical problems (relating to your heart, lungs, diabetes or increased blood pressure) and provide a list of your current and past medications.
Surgical complications can include bleeding, infection, spinal fluid leak, injury to the veins and arteries near the spine or injury to the spine's nerve tissue or its surrounding protective layer. Injury to the spinal cord or the nerves may occur during surgery and can result in complete paralysis of all four limbs or paralysis of certain muscles in the arms or legs, with loss of normal sensation. Loss of bowel and bladder control can also occur following injury to the nerves. An injury to the covering layers of the nerves (dura) can result in a leak of spinal fluid and this may occasionally require a repeat surgery. Great care is taken to ensure the accurate placement of the screws, including the use of intra-operative fluoroscopy (x-rays).
Although antibiotics are given before and after surgery, there is a 1-5% incidence of wound infection. Superficial mild infections can be treated with antibiotics, while deep infections may require a wound wash-out under anaesthesia. If you have had an infection in any other region (urinary bladder, chest and skin) immediately prior to surgery, you may be at a higher risk of post-operative infection in the spine, so let your surgeon know.
Two level anterior
lumbar fusion - side view
Two level anterior
lumbar fusion - front view
Venous thrombosis (DVT: clotting of blood in your calf muscles) and pulmonary embolism are uncommon after an elective spine surgery, particularly when you are out of bed and walking within 24 hours after surgery. We use calf compressors and TED stockings to prevent the clotting of blood in legs; we do not routinely use medications. However, if you have had an episode of DVT in the past, let your surgeon know.
A major risk that is unique to the anterior disc surgery is damage to the large blood vessels that lie in close proximity to the spine leading to excessive blood loss. Quoted rates in the medical literature put this risk at 1% -2%.
One level anterior lumbar
fusion - side view
For males, another risk unique to this approach occurs while approaching the L5-S1 disc. There are small nerves directly over the disc interspace that control a valve that causes the ejaculate to be expelled outward during intercourse. By dissecting over the disc space the nerves can stop working, and without this coordinating innervation to the valve, the ejaculate takes the path of least resistance, which is up into the bladder - a condition known as retrograde ejaculation. The sensation of ejaculating is largely the same, but it makes conception very difficult (special harvesting techniques can be utilized). Fortunately, retrograde ejaculation happens in less than 1% of cases and tends to resolve over time (a few months to a year). This complication does not result in impotence as these nerves do not control erection.
Another risk of this type of spine surgery is that a solid fusion will not be obtained (nonunion) and further surgery to re-fuse the spine may be necessary. Nonunion rates are higher for patients who have had prior lower back surgery, patients who smoke or are obese, patients who have multiple level fusion surgery, and for patients who have been treated with radiation for cancer. Not all patients who have a nonunion will need to have another fusion procedure. As long as the joint is stable, and the patient's symptoms are better, more back surgery is not necessary. In addition, there is a risk of achieving a successful fusion, but the patient's pain does not subside.
Notify your surgeon at once if you notice the following after surgery
- Excessive bleeding
- Redness or discharge from the wound
- Fever
- Persistent headache
- Weakness or numbness in the arms and legs
- Difficulty in passing urine
Talk to your surgeon
This is a brief overview and does not contain all the known facts about your condition and the treatment options. Feel free to seek any clarifications from your surgeon and his team. It is important for you to obtain a clear understanding of your condition and the risks, benefits and limitations of the surgical procedure before proceeding.
