Endoscopic lumbar fusion

In one minute

Endoscopic lumbar fusion joins two vertebrae (the bones of the spine) into one solid piece. Through an endoscope (a thin camera tube) the surgeon removes the worn disc, fills the space with bone graft and a cage (a small hollow spacer), and holds the segment still with screws placed through the skin. It is for a segment that slips or has collapsed, where freeing the nerve alone would not hold. Published series report roughly two to three hours of operating time, most often under general anaesthesia. Most patients walk within a day; the bone takes months to knit.

What the operation is

The full name is endoscopic transforaminal lumbar interbody fusion, shortened to endoscopic TLIF. "Transforaminal" means the surgeon enters through the foramen, the opening at the side of the spine where the nerve root leaves. Relatives are endoscopic PLIF (posterior lumbar interbody fusion, a more central angle), biportal or UBE (unilateral biportal endoscopic) fusion, which uses two small portals, and iLIF (endoscopic assisted intraforaminal lumbar interbody fusion).

A decompression removes what presses on the nerve and leaves the joint alone. A fusion goes further: the disc comes out, graft and cage go in, and screws stop the two vertebrae moving until they grow together.

Who it is for

Fusion is considered when a segment is unstable and the nerve is trapped at the same time: spondylolisthesis (one vertebra slipped forward on the one below) that moves on bending X-rays, a recurrent disc herniation at a level already operated on that has become loose, and foraminal stenosis (narrowing of the nerve opening) where the disc has collapsed so far that decompression alone would leave the nerve pinched.

Many slips do not need fusion. The North American Spine Society (NASS) guideline of 2014 suggests decompression with fusion for symptomatic stenosis with degenerative spondylolisthesis, yet finds that for a single-level, low-grade slip (under 20%) without lateral foraminal stenosis, decompression alone gives equivalent outcomes; both statements are grade B. Back pain alone, without a slip or a trapped nerve, is a weaker reason to fuse.

The published endoscopic fusion series are mostly one-level degenerative cases: 32 of the 42 studies in the 2022 meta-analysis were single-level, the rest one to two or more levels, and the endoscopic-versus-open study was limited to single-segment disease. That is where the technique has been tested so far. Soft bone that cannot hold screws, a high-grade slip, severe central stenosis, infection or deformity usually call for open surgery, described on the spinal fusion page.

How it is done

You lie face down. The endoscopic-versus-open study operated under general anaesthesia; among the endoscopic series in the 2022 meta-analysis, some used general anaesthesia with nerve monitoring, others conscious sedation or local anaesthesia.

A decompression alone is done through a 7 mm incision. Inserting a cage needs a wider corridor: the endoscopic-versus-open study describes a working tube of 11 mm inside diameter through a skin cut of roughly 13 mm. Dilators pass between the muscle fibres without cutting them, part of the facet joint is shaved to open the path, the disc is removed under the camera and the endplates (the cartilage layers on the bone) are scraped to bleeding bone. Graft is packed in and the cage inserted under X-ray guidance, with the decompression and the cage position checked on the screen before the tube comes out. The surgeon then places two screws on each side through stab incisions and joins them with rods. Single-level endoscopic fusion took a mean of about 180 minutes in that study, whose authors cite earlier endoscopic series ranging from about 168 to 286 minutes.

Endoscopic compared with open surgery

Endoscopic TLIF against tubular minimally invasive TLIF (MIS-TLIF): the 2024 meta-analysis of 13 studies and 1,015 patients found similar pain, disability, fusion and complication rates; the endoscopic group lost about 77 mL less blood, left hospital 2.15 days earlier and had less back pain in the first two weeks, while MIS-TLIF was 29 minutes faster. A 2022 meta-analysis of 42 studies agreed: less blood loss, a stay about two days shorter, no significant difference in complications or fusion.

One study of 30 endoscopic against 30 open interbody fusions: blood loss 63 versus 313 mL, stay 3.3 versus 7.0 days, fusion 93.3% versus 96.7%, operation 54 minutes longer with the endoscope.

The honest reading: similar results, less tissue damage, faster discharge, a longer operation, more X-ray exposure, a steep learning curve, and almost all of it observational rather than randomised.

Risks and how we reduce them

The 2022 meta-analysis lists the main complications. Endoscopic fusion: cage migration 1.1%, screw malposition 0.6%, infection 0.6%, pooled 4.7%. MIS-TLIF: screw malposition 1.6%, adjacent segment degeneration 1.5%, dural tears (a leak of spinal fluid) 1.3%, pooled 9.6%. The pooled comparison was borderline (p = 0.05) and the authors conclude that complication rates did not differ significantly.

Non-union, when the bone fails to bridge, is the complication specific to fusion: with fusion rates of 93.3% and 96.7% in the endoscopic-versus-open study, a few patients in every hundred do not knit fully, and a persistent non-union can need a second operation. Smoking works against it: a 2021 meta-analysis of 26 studies and 4,409 patients found that smokers fused significantly less often than non-smokers (odds ratio 0.55). The exiting nerve root can be irritated because the cage passes close to it. Cage subsidence (the cage sinking into soft bone) was 6.7% endoscopic versus 16.7% open in the head-to-head study. Screws hold the cage while the bone knits. Conversion to open surgery remains possible.

What we do: we perform the fusion fully endoscopically, with an interbody cage and percutaneous screws. Across all the team's operations our complication figure is well below 1%; our own figure, not a comparison.

Recovery, week by week

What the evidence says

SPORT (the Spine Patient Outcomes Research Trial, Weinstein and colleagues, 2007) followed 607 patients with degenerative spondylolisthesis: with about 40% crossover in the randomised cohort the intention-to-treat comparison showed no significant difference, while the as-treated analysis showed a substantial advantage for surgery at two years with little evidence of harm.

The American Association of Neurological Surgeons and Congress of Neurological Surgeons (AANS/CNS) fusion guideline of 2014 (Parts 9 and 11) finds that trials consistently show superior outcomes with surgery for stenosis with spondylolisthesis, with most surgical patients having some form of fusion, that no standard fusion technique can be recommended, and that interbody techniques give higher fusion rates than posterolateral fusion when there is instability.

The NASS guideline suggests instrumentation to improve fusion rates but not clinical outcomes, and calls the evidence on minimally invasive versus open technique conflicting.

How we do it at spine.uz

We are Tashkent's first endoscopic spine team, five surgeons operating as one, with 27,600+ endoscopic and spine operations. This page was reviewed by Dr. Shomansur Shotursunov, orthopaedic surgeon. We perform the fusion fully endoscopically: disc removal, decompression and cage placement under the camera, with an interbody cage and percutaneous screws.

Send your MRI (magnetic resonance imaging) and X-rays on Telegram or WhatsApp; a doctor from the team replies by voice within 48 hours, free of charge. After surgery you receive a written conclusion and follow-up on Telegram.

Preparing for the operation

Bring your MRI, standing and bending X-rays, any CT (computed tomography) scan, your medicines list and details of blood thinners so the surgeon can plan when to pause them. If you smoke, surgeons ask you to stop before and after a fusion, because smokers fuse less often than non-smokers in the published series. Expect an anaesthetist review, fasting from the night before and a day or more in the ward.