Why it is done

When the disc wears out, one vertebra slips over another, or ligaments and joints thicken, the intervertebral foramina through which the nerve roots exit become narrower and the nerve is compressed: back and leg pain, tingling, weakness and difficulty walking. Spinal fusion makes it possible to decompress the nerves, restore disc height and immobilise the segment until the bone has fused [1].

The three stages of the operation (example: TLIF)

1. Laminectomy and foraminotomy: the lamina and, on the side of the approach, the facet joint are removed, freeing the nerve root.
2. Interbody cage: the degenerated disc is removed and a titanium cage filled with bone graft is inserted, restoring disc height and keeping the foramen open.
3. Pedicle screws and rods: the screws, inserted through the pedicle into the vertebral body, are connected by two rods: a frame that holds the vertebrae still while they fuse.

TLIF or PLIF?

PLIF (posterior approach) is the “sister” technique of TLIF. In lumbar spondylolisthesis a meta-analysis found comparable clinical results, but with TLIF there were fewer complications, in particular fewer dural and nerve injuries, with shorter operating times and less blood loss [2][3].

The lateral (XLIF) and anterior (ALIF) approaches

In XLIF the disc is reached from the side, through the psoas muscle, using a minimally invasive approach that allows a large cage to be inserted and the nerves to be decompressed indirectly [4]. In a prospective series of 600 cases, perioperative complications occurred in 6.2%, with an average hospital stay of about one day [5]. In ALIF the disc is reached from the front, through the abdomen, without touching the back muscles: it is particularly suitable for the L5-S1 level. These approaches can be combined with percutaneous posterior screws.

When it is considered

• Spondylolisthesis , degenerative or isthmic, with pain and leg symptoms.
• Stenosis of the canal or foramina associated with abnormal segmental motion.
• Recurrent disc herniations or selected degenerative disc disease.
• Deformities such as adult scoliosis.
• Symptoms that persist despite physiotherapy, medication and injections.

Not all back pain requires surgery: surgery is proposed after a thorough consultation, MRI and dynamic X-rays, when the expected benefits clearly outweigh the risks.

After surgery

Patients are usually up and about within the first few days. This is followed by gradual rehabilitation and X-ray checks that confirm, over time, that the vertebrae have fused. Timing and recommendations are always personalised.