Revision IELD

When a fragment of disc is removed, a defect remains in the tough outer wall of the disc. In most people this settles, but in a minority a fresh fragment herniates through the same weakened area later — a recurrent disc herniation that brings the leg pain back. This is a feature of the disc itself rather than a sign of a poor first operation, and factors such as smoking, a large defect in the disc wall and diabetes raise the risk. When a recurrence does not settle and needs surgery, the approach is chosen to fit the anatomy and the position of the fragment.

The choice of corridor in revision surgery follows the same anatomical logic as in primary surgery. At the lowest level of the spine, L5/S1, the pelvis often blocks a from-the-side transforaminal approach, and the interlaminar window is generous — so coming from behind is frequently the more practical route to a recurrent disc there. It is also the natural choice when the recurrent fragment sits in a position best seen from behind. The interlaminar approach does mean working through some of the scar of the previous operation, but it does so with two real advantages over open re-operation: the keyhole is tiny, and the continuous saline irrigation and magnified endoscopic view help define the plane between scar tissue and the nerve far more clearly than the naked eye can.

Under x-ray guidance, the interlaminar window is identified and the working channel docked at its edge. The scar over the previous opening is carefully defined and separated under irrigation, which lifts the tissues and improves the view. The nerve and its covering — the dura — are identified and protected, and the recurrent fragment beneath is mobilised and removed with fine endoscopic instruments. Because scar can be adherent to the dura, this dissection is done slowly and deliberately, always with the nerve in sight. Decompression is confirmed when the nerve lies free and the dural sac pulses normally.

The particular challenge of any revision from behind is that scar tissue sticks to the dura, so the risk of a small tear in that lining is genuinely higher than in first-time surgery. Working through scar right next to the nerve, through a small window, is where magnified endoscopic vision helps and where experience counts most. I am candid with patients that revision surgery is more demanding and, on average, a little less predictable than first-time surgery, and that the decision between removing the recurrent fragment alone and stabilising the level with a fusion is made individually, according to the stability of the level and how many times the disc has recurred. These are exactly the judgements that my focus on endoscopic surgery is built around.

The evidence supports endoscopic revision. The randomised trial by Ruetten and colleagues, which included both interlaminar and transforaminal full-endoscopic revision, found equivalent re-recurrence rates — around six percent — with fewer complications and less tissue trauma than microsurgical revision. Later cohorts, including biportal endoscopic revision series, and a recent systematic review confirm that endoscopic revision achieves good outcomes with acceptable complication rates. Consistent with the honest picture I give patients, the literature also notes the higher risk of dural tears when working through scar in revision surgery, which is why careful, magnified, irrigated dissection matters so much.

Because the muscles and most of the bone are spared, recovery from an interlaminar endoscopic revision is generally quicker than from an open re-operation — many people go home the same day or the next, walking, with relief of the leg pain often early. Some temporary nerve sensitivity can occur in the first weeks and usually settles; numbness and long-standing weakness may take longer and do not always resolve fully. Where a fusion has been added for instability, recovery follows that of a fusion. Care is taken with lifting and bending early on, and the spine is followed up over the longer term.

• —Ruetten S, et al. Full-endoscopic versus microsurgical revision for recurrent lumbar disc herniation (RCT). (PMID 19342934)
• —Kang MS, et al. Biportal endoscopic revisional discectomy for recurrent lumbar disc herniation. (PMID 33228753 / PMC7685633)
• —Yoshikane K, et al. Full-endoscopic discectomy for recurrent lumbar disc herniation: patient-reported outcomes. (PMID 34435151 / PMC8356243)
• —Percutaneous endoscopic lumbar discectomy for recurrent disc herniation: systematic review and meta-analysis. (PMID 40242820 / PMC11998055)
• —Jitpakdee K, et al. Transforaminal versus interlaminar endoscopic discectomy: systematic review and meta-analysis. (PMID 35993298 / PMC9972290)
• —Akmal S, et al. Risk factors for recurrent lumbar disc herniation: systematic review and meta-analysis. (PMID 26765413 / PMC4718239)