Decompression means relief: in this procedure, whatever is pressing on a nerve is removed — prolapsed disc tissue, thickened bone, a thickened ligament. Microsurgical means that this is done under the operating microscope through a small approach, sparing the load-bearing structures. It is the most common procedure on the spine and the standard in a herniated disc and in spinal stenosis when treatment without an operation is not enough. We perform this procedure.
A decompression treats the pressure, not the wear. It makes sense when symptoms, examination and image point to the same place — and when treatment without an operation has not been enough, or when there is no time for it.
Who is decompression suitable for?
The procedure treats symptoms that arise from a constricted nerve: pain that runs into the leg or the arm, numbness, weakness, a short walking distance. Back pain alone is not a reason, and neither is a narrowing on the MRI without matching symptoms.
- Herniated disc of the lumbar spine — if the leg pain persists for six to twelve weeks despite consistent treatment and the MRI finding fits it. Urgent if bladder or bowel are disturbed, if sensation in the area between the legs is absent, or if a paralysis is increasing.
- Spinal stenosis of the lumbar spine — if the walking distance has become so short that everyday life suffers, the symptoms have persisted for months, and movement, physiotherapy, medication and, where appropriate, injections have been exhausted.
- Cervical spine — in a herniated disc with persistent arm pain or weakness, and in compression of the spinal cord. Here the relief is usually achieved from the front, with removal of the disc and insertion of a spacer; that is described on the page Spinal fusion and cage implantation.
- Sciatica that does not recede — sciatic pain is usually the consequence of a herniation or of a narrowing in the nerve exit opening; the rules above apply accordingly.
In spondylolisthesis or another proven instability, the decompression can be combined with a fusion — as a routine that is not indicated. Whether it is necessary in your case is a decision of its own, which we explain on the page spondylolisthesis and further down.
The few situations in which you must not wait are on the page warning signs.
What happens exactly?
At the lumbar spine the principle is the same for herniation and for narrowing: a small window between the vertebral arches through which the nerve is exposed.
- PreparationExamination, review of the images, a conversation about the aim and the limits of the procedure. An anaesthetic consultation, blood values and, depending on previous illnesses, further examinations. Your list of medication is important, especially blood thinners; whether and when they are paused is settled beforehand.
- The procedureUnder general anaesthetic and lying on your front. The correct level is marked with X-ray. Through a short skin incision in the middle of the back, the muscles are held to one side, not cut through. Under the microscope, a little bone is removed from the vertebral arch, along with the thickened yellow ligament, until the dural sac and the nerve root are visible. In a herniated disc the prolapsed tissue is removed; the rest of the disc stays. In stenosis the constricting parts of the facet joints are additionally taken away — from the inside, so that the joints themselves are preserved; both sides can be relieved through one approach. At the end the nerves lie free and can be moved.
- AfterwardsGetting up on the day of the operation or the day after; walking is encouraged. The wound is checked, strength and sensation are tested. In a Swedish study the hospital stay after decompression alone averaged about four days; how long it is for you depends on your condition and on your situation at home.
Endoscopic methods through a thin working sleeve with a camera can come into consideration where the finding is suitable. In a decompression the disc is neither “repaired” nor replaced; replacement with a prosthesis is a different procedure with preconditions of its own.
What decompression can achieve — and what it cannot
In a herniated disc the operation is above all faster. In a Dutch study of 283 patients who had had severe sciatica for six to twelve weeks, leg pain disappeared markedly faster in those operated on early; after one year, however, 95 out of 100 in both groups felt recovered — and 39 out of 100 of those initially treated conservatively had had an operation by then after all. The large American SPORT study with 501 participants produced the same picture: both groups improved markedly, and the differences in favour of the operation were small. IQWiG sums it up: the operation relieves faster; after one to two years, those treated conservatively are no worse off in most studies.
In spinal stenosis the gain is the walking distance. In the SPORT stenosis study with 289 randomised and 365 observed patients, those operated on had markedly less pain and more function after two years — although many of those assigned changed groups, which makes the comparison difficult. A Cochrane analysis found a small advantage of decompression over conservative treatment after two years, at very low certainty of the data; IQWiG calls the evidence contradictory. Put honestly, that means: many of those operated on walk further afterwards, but not all, and some residual symptoms are common.
What decompression does not achieve: it does not reverse the wear, it does not guarantee that a pre-existing numbness will disappear, and it does not treat back pain. Whether a fusion is additionally required depends on the stability — three large randomised trials show that decompression alone gives equally good results after two and five years as decompression with fusion in most people with stenosis, including those with mild spondylolisthesis.
Risks and side effects
As with every operation: infection, post-operative bleeding, thrombosis and the risks of the anaesthetic. Specific to the procedure: an injury to the dura with leakage of cerebrospinal fluid, which is usually closed during the procedure and can cause headaches for a few days; rarely damage to a nerve root with new altered sensation or weakness; a haematoma that presses on the nerves and has to be relieved promptly. After a herniated disc, tissue can prolapse again at the same place; that affects a proportion of those operated on. After an operation for stenosis, the segment can become unstable or the narrowing can return through scarring and further wear. And with every procedure the possibility remains that the symptoms only partly subside.
In figures: according to the IQWiG review, after a decompression for stenosis 6 to 7 out of 100 of those operated on had to go into hospital because of a complication, and in 1 to 2 out of 100 it was life-threatening; after an additional fusion it was 9 to 10 out of 100. In the Swedish comparison study, 21 out of 100 had a further operation on the lumbar spine within an average of six and a half years after decompression alone. Which of these is to the fore in your situation is something we discuss before the procedure.
Before and after
Before the procedure: the decision is not taken in the first consultation. Take the assessment home with you, clear up any open questions, and arrange who will support you in the first few days. Bring all images on a storage medium and your list of medication. Stay in movement until the operation, as far as the pain allows.
After the procedure: walking from the start, sitting at first only briefly and frequently interrupted. For a few weeks no heavy lifting, no twisting under load, no deep bending. Showering is usually possible soon after the wound is closed; bathing and swimming wait until the wound has healed. According to a Cochrane analysis of 22 studies with around 2,500 participants, physiotherapy and rehabilitation programmes that begin four to six weeks after the operation can relieve pain for a few weeks and improve mobility; an earlier start within four weeks also appears to be safe. How long you are unfit for work depends on your occupation. Drive only once you can turn freely and brake firmly if needed. A follow-up check with us is part of it.
Alternatives
The most important alternative is to continue treatment without an operation: movement, physiotherapy, painkillers for a limited time, and for root pain a targeted injection at the nerve root, which we carry out at the practice. In stenosis, walking training, flexed postures and a walking frame often lengthen the walking distance considerably. For pain lasting months, a multimodal pain treatment can come into consideration. Where instability has been proven, the combination of decompression and fusion is an option that we likewise offer. Implants placed between the spinous processes to spread the canal open led in randomised trials to markedly more repeat operations than bony decompression.
Frequently asked questions
Is the disc removed?
Only the part that has prolapsed and is pressing on the nerve. The rest stays as a buffer between the vertebrae. Clearing it out completely brings no advantage and weakens the segment.
How long should I have waited before the operation?
In a herniated disc without paralysis, six to twelve weeks of consistent treatment, because most herniations recede in that time. Where there is a significant or increasing paralysis and where there are warning signs, that does not apply — then time counts in the other direction.
Can the herniation come back?
Yes, tissue can escape again at the same place, because the disc is not replaced. That affects a proportion of those operated on. Strengthening the trunk and the back and a back-friendly daily routine lower the risk; they cannot rule it out.
Does stenosis have to be fused?
Usually not. Three large studies show that decompression alone gives equally good results as decompression with fusion in most people with stenosis — with a shorter stay and less blood loss. Fusion is used where instability has been proven. If a fusion has been recommended to you, ask what the reason is.
What if the numbness remains?
Sensation recovers more slowly than pain, often over months, and some of it can remain — especially if the numbness had already been present for a long time before the operation. A stable numbness that does not increase is unpleasant but not a cause for concern.
When may I work and do sport again?
That depends on your occupation and on the procedure. Walking, and later cycling and swimming, are possible early on; sport with impacts, jumping or heavy lifting waits until the wound has healed and the trunk and back can take load again. We discuss that at the follow-up check.
If you have been advised elsewhere to have an operation, you can obtain a second opinion from us. We look at your images, examine you and tell you frankly whether we share the recommendation — and what happens if you wait for the time being. What you should bring is on the page Your first appointment.