A midline or slightly paramedian incision of approximately 2 cm is made. A series of dilators are passed through the muscle (rather than stripping muscle from bone). A tubular retractor holds the muscle apart, creating a working corridor. Under the operating microscope, the lamina is thinned, ligamentum flavum removed, and the nerve roots decompressed. For bilateral stenosis, both sides can be decompressed through a single midline incision by tilting the tube (over-the-top technique). The operation takes 45–90 minutes per level.
MIS decompression is offered for lumbar spinal stenosis when a less invasive approach is desired — particularly for single or two-level stenosis without instability. It preserves more of the posterior musculature and bony structures than open laminectomy.
Physiotherapy, epidural injection, pain medication, and activity modification — the same as for standard decompression.
MRI confirming stenosis. Assessment for instability (dynamic X-rays) — if unstable, fusion should be added. Day-case or overnight procedure.
Equivalent decompression to open laminectomy with potentially less post-operative pain, shorter hospital stay (often day-case), faster recovery, less muscle damage, and preservation of more posterior stability — potentially reducing the need for later fusion.
Same risks as open decompressionSee standard risks
Dural tear, nerve injury, infection.
Conversion to openUncommon
If decompression is inadequate through the tube. Approximately 2–5%.
Learning curveExpected
The tubular technique requires specific training.
Dural tearUncommon
Risk approximately 3–5%, similar to open.
Incomplete decompressionUncommon
The limited field of view may result in inadequate decompression, particularly for central stenosis.
Nerve injuryRare
Risk approximately 1%.
InfectionUncommon
Wound or deep infection.
InstabilityUncommon
If significant bone is removed despite the minimally invasive approach.
General anaesthesia. Prone position. Day-case in many centres.
Most patients go home the same day or next morning. Walking immediately. Minimal wound care. Return to desk work at one to two weeks. Driving at one to two weeks. Full activity at four to six weeks. Recovery is generally faster than open laminectomy.
Review at six weeks. Further follow-up as needed.
Is MIS decompression as effective as open?
Yes — the decompression achieved is equivalent. The advantage is in the approach — less muscle damage, less pain, and faster recovery. Long-term outcomes are equivalent.
Can this be done as a day case?
Yes — many MIS decompressions are performed as day cases, with patients going home a few hours after surgery. This is one of the significant advantages over open laminectomy.