Thoracic Endoscopic ULBD (TE-ULBD)

The ligamentum flavum is a ligament that runs along the back of the spinal canal. In the thoracic spine it can, in some people, gradually turn to bone — a process called ossification of the ligamentum flavum, or OLF. As it thickens and hardens, it presses on the spinal cord from behind, producing thoracic myelopathy: difficulty walking, problems with balance and coordination, numbness in the legs and trunk, and sometimes bladder symptoms. Because the cord is involved, and because pressure left untreated can cause lasting harm, decompressing it in good time is important. This is the most common reason for a thoracic decompression, and it is chiefly a bone-removal problem.

The operation applies the same elegant principle I use in the lower back. The endoscope enters through a keyhole on one side of the back, and by angling across underneath the bony roof of the canal — over the top of the cord — the ossified ligament and overgrown bone crowding the cord are removed on both the near and the far side through that single small opening. The hardened ligament is taken down carefully with fine burrs, often lifting it away from the cord as a block once it has been freed all round. Because only one side is opened and the muscles and much of the bony architecture on the far side are preserved, the stability of the spine is largely maintained — frequently avoiding the fusion that a wide open decompression might require.

I want to be especially measured here, because decompressing the thoracic cord is among the highest-stakes work in spinal surgery and must be approached with great caution and careful patient selection. The cord in this region has a relatively poor blood supply and tolerates handling badly; the decompression must be complete, the cord must never be pressured, and bleeding must be controlled meticulously. Working a fine drill over the top of a compressed cord leaves essentially no margin for error. Not every case of thoracic stenosis is suited to an endoscopic approach — the extent and shape of the ossification, the number of levels, and the state of the cord all bear on the decision, and reserving the endoscopic route for cases genuinely suited to it is as much a part of the expertise as the technique itself.

The evidence for endoscopic thoracic decompression is emerging and favourable, though younger than the lumbar evidence, which is exactly why careful selection matters. A systematic review and meta-analysis comparing endoscopic decompression with open laminectomy for thoracic OLF found good recovery rates, with the endoscopic approach positively associated with neurological recovery. A comparative cohort of thoracic endoscopic ULBD against open laminotomy for OLF reported a lower complication rate with the endoscopic technique. Full-endoscopic and biportal endoscopic series — several performed under local anaesthesia — report meaningful improvement in myelopathy scores, with the tissue-sparing benefits of a keyhole approach. As with all newer techniques, the literature rightly stresses meticulous technique and appropriate selection.

Where TE-ULBD is appropriate, the keyhole, muscle-sparing nature of the operation means recovery is often quicker and more comfortable than an open decompression, and the stability of the spine is preserved. Improvement in myelopathic symptoms — walking, balance — can be gradual, and the aim of surgery is often to halt progression and allow recovery over time rather than to reverse everything at once. Because this is advanced surgery, the plan is always individualised after a thorough assessment, and neurological function is followed up carefully over the longer term.

• —Kumar V, et al. Endoscopic decompression versus open laminectomy for thoracic ossified ligamentum flavum: systematic review and meta-analysis. (PMID 39037535)
• —Uniportal thoracic endoscopic laminotomy with bilateral decompression versus open laminotomy for thoracic OLF: comparative cohort. (PMID 35383681)
• —Biportal endoscopic posterior thoracic laminectomy for myelopathy from ossification of the ligamentum flavum. (PMID 37016861 / PMC10080434)
• —Percutaneous full-endoscopic posterior decompression of thoracic myelopathy caused by ossification of the ligamentum flavum. (PMID 30656471)
• —Surgical results and prognostic factors after full-endoscopic posterior decompression for thoracic OLF myelopathy. (PMC6987090)
• —Percutaneous endoscopic versus posterior laminectomy for thoracic ossified ligamentum flavum: retrospective comparison. (PMID 35246092 / PMC8895858)