Endoscopic foraminotomy

In one minute

Endoscopic foraminotomy frees a nerve root pinched in the foramen (the bony opening on each side of the spine through which the nerve leaves) or in the lateral recess (the gutter at the side of the canal just before that exit). The surgeon shaves away the bone spur and thickened ligament narrowing the passage through a 7 mm incision, usually under local anaesthesia with sedation. It is for one-sided leg pain that follows a single nerve and has not settled with non-surgical care. No implants are used and the joint is kept. Most patients walk the same day and go home within 24 hours.

What the operation is

Foraminal stenosis develops when a disc loses height and the facet joint above it enlarges, so the opening between two vertebrae shrinks around the nerve. Lateral recess stenosis is the same process one step further in, where the upper edge of the facet presses the nerve against the back of the vertebral body. Both are often under-described on an MRI (magnetic resonance imaging) report that concentrates on the disc.

Foraminotomy means enlarging the foramen. Foraminoplasty is the same idea seen from the endoscope: reshaping the tip of the superior articular process (the upward-pointing part of the facet that forms the back wall of the foramen) with a burr and punches until the exiting nerve is free. TELDF (transforaminal endoscopic lumbar decompression and foraminoplasty) is the name used in the British long-term series; para-PSLD is the paramedian version of the PSLD (percutaneous stenoscopic lumbar decompression) technique, described by Dr. Kangtaek Lim's group for foraminal and extraforaminal lesions. Removed: bone from the tip and underside of the facet, the thickened ligament, and any disc bulge pressing the nerve. Kept: the rest of the facet joint, the disc and the muscles.

Who it is for

The operation is for foraminal or lateral recess stenosis on MRI or CT (computed tomography), with leg pain, numbness or weakness in the territory of that nerve, after non-surgical care has failed; the North American Spine Society (NASS) guideline on degenerative lumbar spinal stenosis frames the decision.

It also suits situations where open surgery is unattractive: the level next to a previous fusion, a previously operated segment with scar in the canal, and older patients with heart or lung disease who are better off without general anaesthesia. The British 10-year series was made up of patients who had failed rehabilitation, pain management or surgery, and the operation helped those with failed back surgery as much as the others.

It is not the right tool when the segment is unstable, when the main problem is central stenosis, or when back pain rather than leg pain dominates; then we discuss decompression or fusion instead.

How it is done

You lie face down or on your side. The transforaminal route is done under local anaesthesia with sedation: the Croatian five-year series used local anaesthesia with intravenous analgesia, and the British series describes an aware-state procedure. You stay responsive so that you can tell the surgeon at once if the nerve is touched; the anaesthetist and surgeon decide per patient.

Under X-ray guidance a needle is placed from the side into the foramen, followed by a guidewire, a dilator and the working tube; the incision is 7 mm. With a burr and punches the surgeon shaves the facet tip and the bone spur, removes the thickened ligament and trims any disc bulge, until the nerve lies free with a clear margin above and below it. For the lateral recess the same work is done from the back through the interlaminar window. In the BMJ trial the transforaminal route, which enlarges the foramen with a drill before the disc is reached, took a median of 30 minutes; a bony foraminotomy takes longer, depending on how much bone has to go.

Endoscopic compared with open surgery

There is no randomised trial of endoscopic against open foraminotomy that we could cite, so the comparison rests on series. The open alternatives are partial removal of the facet joint from the back, which risks destabilising the segment, or decompression with fusion. The endoscopic operation removes only the part of the facet that presses on the nerve, from the side, without touching the muscles or the midline.

In the British 10-year study of 114 patients, 79 of whom were reviewed at 10 years, pain fell from 7.3 to 2.4 on a 10-point scale and disability from 58 to 18, 72% rated their result excellent or good, and 77% were able to return to or continue in work or retirement activity. In the Croatian series of 46 patients, 37 kept at least a 50% reduction in both pain and disability through 60 months, with no surgery-related complications. In a Chinese series of 64 patients, leg pain fell from 7.3 to 1.4 and disability from 75 to 23, 91% were rated excellent or good, the foraminal area more than doubled, and alignment and disc height did not change, which argues against destabilisation.

Risks and how we reduce them

• Transient nerve irritation. The exiting nerve sits in the working corridor, and burning or tingling in its territory for days to weeks is the most common complaint: 19% of the British cohort for two to four weeks, none in the Croatian series. Local anaesthesia with sedation, which keeps the patient responsive so that nerve contact is reported at once, is the safeguard both series rely on; in the Croatian series the approach was changed whenever the patient reported pain from the instrument.
• Dural tear: 1.3% for the transforaminal route in pooled endoscopic discectomy studies, and about 1% across 64,470 lumbar endoscopies in an international surgeon survey. A small tear is sealed during the operation.
• Incomplete relief: nine of 46 in the Croatian series did not reach a 50% improvement, and 28% of the British cohort did not rate their result excellent or good. A second pain source that the operation could not address is one reason, which is why the MRI is matched to the examination before any decision to operate.
• Instability: not seen on follow-up imaging in the 64-patient series. The technique removes the facet tip, not the joint.
• Infection: none in the British or Croatian series.
• Conversion to open surgery: possible if the foramen cannot be reached safely, for example with a high pelvic rim at L5-S1.

Across the team's own operations, complications have been well below 1%. That is our figure, not a comparison with anyone else.

Recovery, week by week

Day 0. Walking the same day; home within 24 hours for most. In the British series everyone left by the next morning.

Days 1 to 3. Short walks, no lifting. Tingling in the leg in this window is expected, not a sign of failure.

Week 2. The nerve irritation, if it came, is fading; in the British series it lasted two to four weeks. Desk work and short drives are usually possible.

Week 6. Physiotherapy for the hip and trunk starts; physical jobs and sport are discussed at this visit.

Month 3 to 6. The Croatian series measured at six months, and the gains seen then held through 60 months in most patients. Numbness improves slowest.

Year 1 and beyond. The British series followed patients for 10 years; the improvement in pain and disability was still present at the end, despite ageing and other illnesses.

What the evidence says

• Knight and colleagues, International Journal of Spine Surgery 2014: 114 patients followed for 10 years after transforaminal endoscopic foraminoplasty; sustained improvement, transient nerve irritation in 19%.
• Houra and colleagues, International Journal of Spine Surgery 2022: 46 patients under local anaesthesia; 37 kept at least a 50% improvement at 60 months, no complications.
• Yu and colleagues, Orthopaedic Surgery 2024: 64 patients; 91% excellent or good, foraminal area up 143%, no loss of alignment or disc height.
• Nam, Lim and colleagues, Asian Spine Journal 2019: the paramedian PSLD approach for foraminal and extraforaminal lesions.
• Jitpakdee and colleagues, Global Spine Journal 2023: the transforaminal route is the one for foraminal lesions and allows local anaesthesia.

How we do it at spine.uz

We are Tashkent's first endoscopic spine team: five surgeons operating as one team, 27,600+ endoscopic and spine operations in total. Dr. Kangtaek Lim, founder of the uniportal PSLD technique, trained the team. The incision is 7 mm, most decompressions are done under local anaesthesia with sedation rather than general anaesthesia, and no implants are used.

Send your MRI on Telegram or WhatsApp. A doctor from the team replies by voice within 48 hours, free of charge, saying whether the foramen is the problem, whether a foraminotomy alone would be enough, and whether fusion would be the honest answer. The in-person consultation ends with a written team conclusion, and follow-up continues in the same chat.

Preparing for the operation

Bring the MRI files and a CT if you have one, since bone spurs show better on CT, reports of any previous spine operation, a list of your medicines, and someone to take you home. Tell us about blood thinners, diabetes and heart or lung conditions; the anaesthetist decides what to stop and when to stop eating.