Anterior Lumbar Interbody Fusion (ALIF)

What is ALIF surgery?

Anterior Lumbar Interbody Fusion (ALIF) is a spinal fusion procedure performed through a small incision in the front of the abdomen — the anterior approach — to access the lumbar spine without disturbing the muscles of the back. The damaged intervertebral disc is removed, a large interbody cage packed with bone graft is inserted, and the two adjacent vertebrae are fused together.

The key advantage of the anterior approach is preservation of the posterior spinal muscles. Because ALIF accesses the disc from the front, the large paraspinal muscles at the back of the spine are completely untouched, which reduces postoperative back pain and allows superior restoration of disc height, spinal alignment, and lumbar lordosis compared to posterior approaches.

ALIF is may be combined with a posterior stabilisation procedure — pedicle screws and rods inserted through small back incisions — to provide circumferential (360-degree) fusion and maximum stability. At One Brain and Spine, ALIF is performed by our neurosurgeons in collaboration with a specialist vascular surgeon who performs the abdominal approach.

When is ALIF recommended?

• Spondylolisthesis — slippage of vertebra, particularly at L4-L5 and L5-S1
• Severe degenerative disc disease with significant disc collapse and deformity
• Recurrent disc herniation at L4-5 or L5-S1
• Revision surgery after failed posterior approaches — when posterior scarring prevents safe re-entry
• Adjacent segment disease after prior fusion
• Lumbar deformity correction requiring restoration of lordosis

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ALIF provides particularly large disc space reconstruction and superior lordosis restoration compared to posterior techniques, making it the preferred approach for lower lumbar levels (L4-5 and L5-S1) when significant disc height and alignment correction is needed.  It may also be utilised as a first stage procedure in spinal deformity procedures to ensure a strong fusion base.

Preoperative Preparation

You will have a consultation with a One Brain and Spine neurosurgeon including clinical assessment and radiological imaging including MRI, standing X-rays, and CT scans.  Once surgery is decided as the next step, a vascular surgery consultation is arranged preoperatively. The procedure is performed in conjunction with the vascular surgeon performs the abdominal approach and exposure, then One Brain and Spine's neurosurgeon performs the discectomy and fusion. Blood thinners are ceased before surgery. 

What Happens During ALIF?

The patient is positioned supine (face-up). The vascular surgeon makes a small incision in the lower abdomen and carefully retracts the abdominal contents and blood vessels to expose the front of the lumbar spine.  Because this dissection uses natural tissue planes without cutting major muscles, postoperative abdominal pain is typically less than after traditional open abdominal surgery.

Once the spine is exposed, the neurosurgeon removes the intervertebral disc completely — a more extensive discectomy than possible from posterior approaches. A large interbody cage (significantly larger than those used in a posterior approach) is inserted with bone graft, precisely restoring disc height and lumbar lordosis. Screws inserted into the vertebral body through the cage provide immediate stability.

In many cases, the procedure is then supplemented with posterior pedicle screw fixation at which point the patient is repositioned prone (on their stomach) and pedicle screws are inserted through small back incisions under navigation guidance, providing circumferential stabilisation. 

Total operative time is typically 2-3hours. Hospital stay is 3 to 5 days.

ALIF-Specific Advantages

• Complete disc removal from the front — superior endplate preparation and cage sizing
• Largest possible interbody cage — maximising fusion surface area and bone graft volume
• Superior lordosis restoration — best correction of disc height and lumbar curve
• No posterior muscle disruption — less postoperative back pain than a posterior fusion
• Avoids posterior scar tissue — ideal for revision surgery

Abdominal Recovery

In addition to the standard lumbar fusion recovery, ALIF patients experience abdominal discomfort and mild bowel disturbance for the first one to three days as the bowel recovers from retraction. Diet progresses from clear fluids to normal over 1 to 2 days. Abdominal wound care is required in addition to the back wound.

Outcomes of ALIF Surgery

ALIF achieves excellent fusion rates exceeding 90% at 12 months. For spondylolisthesis and significant disc degeneration at lower lumbar levels, ALIF provides superior disc height and lordosis restoration compared to posterior techniques. Most patients experience significant improvement in leg pain; back pain improvement is variable but occurs in the majority. ALIF is particularly effective for restoring spinal alignment in deformity correction.

Risks and Complications

General Surgical Risks

• Wound infection — approximately 1–2%; higher for multilevel procedures
• Bleeding — intraoperatively or postoperatively; rarely requires return to theatre
• CSF leak — approximately 1–2%

Fusion-Specific Risks

• Non-union (pseudarthrosis) <5% — failure of the bone to fuse; more common in smokers, multi-level surgery, and poor bone quality; may require revision surgery
• Nerve injury (<1%) — persistent or worsening leg pain, numbness, or weakness
• Implant malposition or failure (<1%) — minimised by intraoperative navigation
• Persistent back pain — fusion does not guarantee resolution of back pain
• Bowel or bladder dysfunction — rare

ALIF-Specific Risks

• Vascular injury — injury to the aorta or vena cava during anterior approach; rare in experienced hands; managed by the vascular surgeon
• Retrograde ejaculation — injury to the sympathetic nerves anterior to the spine can impair ejaculatory function in men; occurs in approximately 1% of L5-S1 ALIF cases
• Bowel or ureteric injury — very rare
• Ileus — temporary delay in bowel function; usually resolves within 2–3 days