Minimally Invasive Anterior Lumbar Interbody Fusion

Why I do it

When performed in appropriate patients with good technique, this is the most reproducible and effective way of treating both post-traumatic and degenerative disc pathology. Several published papers demonstrate greater than 99% success.

Who should be treated?

Patients with disc injuries or degeneration at the L5/S1 level are the most appropriate patients for this surgery. Ideally the patients should have undergone a course of nonoperative treatment ensuring that their posture is corrected as much as possible, that they have good core muscle control and that their weight is appropriate. If having achieved these three objectives their pain is still of such an intensity as to prevent them from participating in life and activities of daily living, and the disc pathology is seen to be severe enough on MRI scanning, in my hands this would normally include loss of the normal white signal within the disc, loss of the height of the disc, loss of the normal angulation (lordosis) and changes in the bone above and below the disc. Barring any obvious anatomical barriers to performing the procedure, this would be my method of choice for reconstructing and fusing the L5/S1 disc.

Technique

The surgery is performed with the patient lying on their back. A lumbar roll is placed at the base of the lumbar spine to open up the front of the disc. The x-ray machine is brought in and the surgical incision is planned to minimise the damage to the musculature and provide the most direct trajectory to the disc. The skin is cut horizontally, typically over a distance of 6-8 cm. Often a patient’s previous caesarian incision can be used but typically the incision needs to be perhaps a quarter of the length of the caesarian scar. Once the skin has been cut horizontally, a vertical split is made between the two sides of the abdominal six-pack (no muscle is cut). It is then possible to gently peel away the peritoneum (the filmy tissue that contains the intestines) from the side of the abdominal wall. NB. No abdominal contents are removed from the body at any stage. The abdominal contents are swept to the patient’s right-hand side which exposes a view of the L5/S1 discs between the major blood vessels to and from the legs, the iliac veins and arteries. The anterior longitudinal ligament is cut. The disc is entered and gently distracted up to accept an appropriate sized implant that gives an adequate degree of space for the nerves and angulation at the junction between the lumbar spine and the pelvis. Sometimes the microscope is brought in to ensure that no remaining disc tissue is touching either the cauda equina (the base of the spinal cord) or the exiting L5 nerve roots. Under x-ray guidance two threaded cylindrical tapered cages are then inserted into the disc space. These are packed with an artificial bone graft sold under the commercial name Infuse but technically speaking are containing a biologic product called recombinant human bone morphogenetic protein type 2.

X-rays are then taken to confirm adequate restoration of disc height and angulation and correct positioning of the implants. Blood flow to the toes is checked. The abdominal contents are left to fall back into place and the wound is closed with three layers of absorbable stitches.

Typically the patient’s require no catheterisation. Upon waking up, patients will notice pumps on their calves to prevent the development of clots of deep venous thrombosis but most patients walk on the day of surgery and are able to toilet and shower themselves by day two or three post-surgery.

Risks

  1. Deep infection. The last 300 of these procedures we have performed we have had no deep infections.
  2. Superficial infection requiring washout of the wound and reclosure. We have had one of these complications.
  3. Nerve damage. We have had no reported or documented cases of damage to the nerves to the legs, bowel or bladder. We have had three male patients with a rare complication of short-lived retrograde ejaculation. This refers to damage to the nerves that close the bladder at the time of orgasm which results in semen passing into the bladder rather than out of the tip of the penis. This is obviously a very disturbing complication for the patients who suffer from it, but thankfully to date this has not been permanent in any cases.
  4. Major blood loss requiring transfusion. This has occurred in two of our patients due to the damage to the internal iliac veins. I perform all of these procedures with an assistant surgeon who specialises in general surgery in this area and on both of these occasions the patient has suffered from no long term deleterious effects.
  5. Non-union. This refers to the bone graft not taking. This has occurred in three patients all of whom were reasonably heavy smokers. It has been widely demonstrated that the union rate is 99% or greater using this technique but drops away to perhaps 50% in patients who smoke nicotine.
  6. Deep venous thrombosis. This refers to a clot developing in the calf muscles or higher in the legs that at worst case scenario propagates to the lungs and causes shortness of breath and/or death. We have had two documented cases of pulmonary embolus. To prevent this from occurring, first and foremost we encourage patients to get up on the day of surgery. Secondly, they are fitted with calf pumps. Thirdly, most patients will be given injectable blood thinners on the night or surgery and asked to take Aspirin for six weeks post-surgery.
  7. Transient radiculopathy secondary to the bone graft. Infuse as a bone graft substitute is a very potent chemical. Some patients develop a severe reaction to this with worsening of the leg pain they had before surgery. Typically this will occur somewhere between day four and week three from surgery. Most patients will respond to medicines such as oral steroids or Gabapentin. If it is particularly severe a CT-guided transforaminal epidural steroid injection will help to settle the pain down. Thankfully to date we have had no patients who have had radiculopathy that has lasted for more than 12 weeks but when it occurs it can be quite distressing.
    In summary, the anterior lumbar approach is a minimally invasive, highly successful and relatively safe surgical procedure for the treatment of either post-traumatic or degenerative disc disease at the L5/S1 level.

In summary, the anterior lumbar approach is a minimally invasive, highly successful and relatively safe surgical procedure for the treatment of either post-traumatic or degenerative disc disease at the L5/S1 level.

How we approach your care
by Dr Ferguson

We provide efficient and professional care throughout your time as our patient.

Your initial contact will see us begin your journey to recovery. The first stage is non-invasive high tech imaging of the problem causing area.

Next, you will come and meet the team, sit with me to discuss your situation and your available options.

If you do proceed to have surgery, we will guide you through the process with experience and patience.

Our team provides excellent post op care through a range of methods. We have regular follow ups with you, throughout your recovery period. Whether that be weeks, months or years.

We are available to answer any questions that you may have, and will work with you to reduce any worries that occur.

If you would like to make an enquiry, contact us

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