A narrow spinal canal – Knowledge

1. Why this text?

The report sounds alarming: "high-grade spinal stenosis", "narrowing of the dural sac", "compression of the nerve roots". Many people read something like that and think first of paralysis. And on top of it comes everyday life, which had already become unpleasant: the walking distance gets shorter, after two hundred metres the legs need a rest, standing at the checkout is harder than walking there.

"Spinal stenosis" translated literally means nothing other than a narrow spinal canal. It describes something visible on a scan – not a statement about how you are and how you will be. That is the most important sentence in this text, and it is well supported: in a Japanese population study three out of ten people had a markedly narrow canal on the scan – and only about one in six of those people also had the matching symptoms [6].

The second piece of good news concerns the course. Contrary to what many expect, it does not inevitably get worse and worse. In long-term observations over ten years, about a third stayed the same, a third improved and a third got worse [18]. And if you are treated conservatively first and only have surgery later, you lose nothing by it: in a ten-year study, delayed surgery led to essentially the same results as early surgery [19]. So you may take your time over the decision.

There are, however, two exceptions, and they matter. First, there are rare emergency signs – which ones, is in section 4. Second, the relaxed waiting applies only to the lower back. In the neck, a narrow canal is a different disease with different rules; see section 10.

This text explains what becomes narrow in the spinal canal and why, why walking hurts and sitting helps, what an MRI really tells you, how the condition develops, what physiotherapy can and cannot achieve – and, as a chapter of its own, what surgery does and does not deliver. All statements are referenced; the numbers in square brackets point to the reference list at the end.

One note in advance: this article does not replace individual advice. Anyone who has already had surgery, who has an additional disease of the spine or the nerves, or who has severe neurological deficits will receive a recommendation tailored to their own situation during treatment – and that takes precedence over everything described here.

2. What a narrow spinal canal is

2.1 The canal and what lies inside it

The spine consists of individual vertebrae, and each vertebra has a solid body at the front and an arch at the back. Stack the vertebrae on top of one another and these arches form a continuous tunnel: the spinal canal. The nerve tissue lies protected inside it.

In the lower back – the region this text is mainly about – the spinal cord itself is no longer present. It ends at about the level of the first lumbar vertebra. Below that, only a bundle of individual nerve roots continues, called the cauda equina because of how it looks: "horse's tail". These roots run downwards and leave the canal sideways through small openings to reach the legs, the bladder and the bowel.

Narrowing can occur in three places, and reports name them accordingly:

• Central – the tunnel itself becomes narrower and the whole bundle of nerves has less room.
• In the side corner (technical term: lateral recess) – where a single root turns outwards.
• In the exit hole (technical term: neural foramen) – the opening through which a root leaves the spine.

This explains why the symptoms can differ so much: if the narrowing is central, it usually makes itself felt in both legs. If only one side channel is affected, the picture resembles a herniated disc, with symptoms in one leg.

2.2 Why the canal becomes narrower

In the vast majority of cases the narrowing is not congenital but has developed over decades. Three changes work together, and all three are part of the normal ageing of the spine [1], [3]:

• The disc becomes flatter and in doing so bulges slightly backwards into the canal. Like a cushion you sit on: it loses height and becomes wider at the edges.
• The small spinal joints at the back (technical term: facet joints) therefore carry more load and become thicker – the same thing that happens with osteoarthritis in a knee or hip. Except that here the thickening protrudes into the canal from behind.
• The yellow ligament (technical term: ligamentum flavum), which lines the vertebral arches on the inside, thickens and buckles into folds as the spine loses height.

In some people there is also a slipped vertebra (technical term: spondylolisthesis): one vertebra slides forward a little relative to the one below, and what used to be a straight tunnel now has a step in it. This matters because it changes the question of surgery (see section 8.3).

And a smaller proportion of people have a rather narrow canal from birth. They have less reserve: in them, smaller degenerative changes are enough to make it too tight – and symptoms often begin earlier in life [5].

What is not in this section: a question of blame. There is no posture, no sport and no wrong movement that causes a narrow spinal canal. The changes take decades and largely follow your own predisposition.

2.3 Why walking hurts but sitting helps

This is the observation that occupies people most – and there are two good explanations for it.

The first is mechanical. The spinal canal changes its width depending on how you stand. When you straighten up, and even more when you lean back, the small spinal joints slide into each other and the yellow ligament buckles more – the canal becomes narrower. Bending forward does the opposite: the folds stretch smooth and the canal becomes measurably wider. That is why everything that rounds the back relieves the symptoms, and everything that extends it makes them worse [1], [3].

The second is blood supply. Nerve roots need more oxygen when you walk than at rest – they are working. Normally they then receive more blood. If the canal is narrow, the fine veins around the roots are congested and the extra blood flow does not get through. The root ends up undersupplied and reports this with pain, burning, heaviness and numbness [4].

This second explanation is so useful because it describes what ends the symptoms: as soon as the load stops and the position changes, the blood supply normalises. That is exactly what people experience – after one or two minutes of sitting it is fine again.

The one sentence to take away: the symptoms are not caused by damage you do while walking, but by a temporary undersupply. Walking to your limit breaks nothing – it only shows where the limit currently lies.

2.4 "Narrow on the scan" is not the same as "ill"

This is where the gap is largest between what a report suggests and what it means. Two large population studies show it clearly.

The Wakayama study from Japan examined 938 people aged between 40 and 93 with an MRI – regardless of whether they had symptoms. In 77.9 % the canal was at least moderately narrow, in 30.4 % markedly narrow. And of those with marked narrowing, only 17.5 % had the matching symptoms [6]. In other words: five out of six people with an alarming scan noticed nothing.

The Framingham study from the USA measured the canal on computed tomography. In the 60-to-69 age group, 47.2 % had narrowing in the wider sense and 19.4 % clear narrowing in the stricter sense [5]. That study also found, however, that clear narrowing goes together with back pain – more often than in others. Both belong together: the finding is common, and it is still not meaningless.

A pooled analysis of 41 papers arrives at the same picture: depending on whether you go by symptoms or by imaging findings, the frequency estimates differ widely – and the authors explicitly point out that the underlying studies are methodologically weak [7]. All the other signs of spinal ageing are likewise very common in people without symptoms and increase steadily with age [8].

On top of this there is a problem with the images themselves: there is no uniform measurement above which a canal counts as "too narrow". A systematic review found ten different measurement methods side by side. The ones most often used are a diameter below 10 millimetres or a cross-sectional area below 70 square millimetres – but none of these thresholds is binding [9].

And finally: even in people who are being treated for their symptoms, the degree of narrowing says little about the degree of pain. A Swiss cohort study examined this thoroughly in its participants and found no useful association between MRI measurements and pain in the buttock, leg or back [10].

This is how it can be summarised: the scan says how narrow it is. It does not say how severe your symptoms are, and it does not say what happens next. The diagnosis only emerges when scan, history and examination tell the same story.

3. What a narrow spinal canal feels like

3.1 The leading symptom: trouble that comes on walking

The typical picture is called neurogenic claudication; "neurogenic" means arising from the nerves, and "claudication" means limping – because those affected have to keep stopping while walking. In German it is often called the "shop-window disease of the spine", after the habit of pausing in front of shop windows.

The sequence is characteristic:

• While walking or standing for longer, pain, burning, heaviness, fatigue or tingling develops in one or both legs – often from the buttock downwards.
• The symptoms start after a fairly consistent distance: "after about 300 metres", "after two blocks".
• They ease when you sit down or bend forward – usually within a few minutes.
• Afterwards you can walk a similar distance again.

Many people also describe that walking uphill is easier than downhill – uphill you lean forward, downhill you straighten up. And that cycling works surprisingly well, even for someone who has to stop after 200 metres on foot. The reason is always the same: the forward-leaning position.

Back pain is often part of the picture but rarely dominates it. Anyone who complains mainly of their back and gets no leg symptoms when walking most probably has a different problem – see our article on back pain.

3.2 The shopping trolley sign

There is an everyday observation so reliable that it appears in textbooks: in the supermarket many people can walk for a surprisingly long time – as long as they lean on the shopping trolley. Without the trolley it is over after a short while. The reason is once again the posture: the trolley allows a slight forward lean.

These and similar observations have been systematically examined for how strongly they support the diagnosis. A review of four studies with 741 people investigated for leg symptoms produced the following picture [11]:

In practice this means two things. First: these questions are not small talk, they are the actual examination. Second – and this is the more honest half: these features are most reliable at ruling the diagnosis out. No single finding proves it [13].

3.3 Numbness, weakness, unsteady walking

Alongside the symptoms brought on by walking, the following are common:

• Sensory disturbance – numbness or tingling, often in the soles of the feet, sometimes described as "walking on cotton wool".
• Loss of strength – difficulty climbing stairs or getting up from a chair, occasionally a foot that catches while walking.
• Unsteadiness when walking – a wide-based gait, swaying in the dark or with the eyes closed. This happens because the feedback from the legs becomes less precise.

The last point deserves particular attention because it is directly linked to the risk of falling. Those who walk less steadily fall more often, and those who fall then walk even less. How to break that cycle is described in our article on fall prevention.

Important for context: numbness that comes on when walking and goes again when sitting is unpleasant but not threatening. Weakness that is new and increasing and persists at rest should be assessed medically without delay – see section 4.

3.4 What else may lie behind it

Leg pain when walking is not the same thing as a narrow spinal canal. The most important confusion concerns the blood supply to the legs [1], [2]:

Other possibilities that are considered:

• Hip osteoarthritis – pain in the groin that increases with walking but does not improve with bending forward. See our article on hip osteoarthritis.
• Polyneuropathy – damage to many fine nerves, for instance in diabetes. Typically the symptoms occur independently of activity, are often worst at night, and affect both feet evenly, as if in a sock.
• A single irritated nerve root – pain in a clearly defined strip of one leg, independent of walking; see herniated disc.

These distinctions are not academic: narrowed leg arteries are treated quite differently and are a warning sign for the heart and circulation as a whole. That is why feeling the foot pulses is part of the assessment.

4. The warning signs – when it is urgent

By far the largest part of cases is unpleasant but not dangerous. There is, however, a rare emergency: cauda equina syndrome. The name refers to the bundle of nerves below the spinal cord (see section 2.1). If this bundle is suddenly compressed severely, the bladder, the bowel and sensation in the sitting area can be permanently damaged – within hours to a few days.

Go to the emergency department immediately – do not wait, not until tomorrow:

• You can no longer hold or pass urine; the bladder feels full but nothing comes.
• You no longer feel when the bladder is filling, or you no longer feel the urine as you pass it.
• Stool passes unnoticed, or the sphincter feels weak.
• Numbness in the area that rests on a saddle – perineum, genitals, inner thighs ("saddle anaesthesia").
• New severe pain or rapidly increasing weakness in both legs.
• New disturbance of sexual sensation.

These signs are described consistently in guidelines and are used worldwide for initial triage [16]. It is a matter of time: the earlier the pressure is relieved, the better the prospect that bladder and bowel function return completely.

For reassurance – and this is just as important: cauda equina syndrome is rare. A systematic review estimates the frequency at about 0.3 to 0.5 cases per 100,000 people per year [17]. The great majority of people with a narrow spinal canal never develop it. The list is there so that you react correctly in the rare case – not so that you check yourself every night.

Have this assessed medically within a few days, but it is not an emergency:

• Weakness in the leg that is new or increasing and persists at rest – especially if the foot catches while walking.
• Pain that is unbearable despite medication and makes sleep impossible.
• A walking distance that shortens markedly within weeks.
• Fever, unintended weight loss, a history of cancer or a recent serious infection – together with new back pain.
• A fall or accident as the trigger, especially with known osteoporosis.
• Cold, pale legs, absent foot pulses or calf pain that stops as soon as you stand still – that points to the arteries (see section 3.4).

And the signs in the neck, which carry an urgency of their own, are in section 10.

5. How the diagnosis is made

5.1 The conversation contributes most

It sounds old-fashioned, but it is true: the most important clues come from your account. After what distance do the symptoms begin? What exactly do you feel – pain, heaviness, tingling, numbness? What ends them: standing still alone, or only sitting down? What is it like walking uphill, cycling, with a shopping trolley? And: how was it six months ago – the same, better, worse?

There are even validated questionnaires for exactly these questions. A Japanese self-report tool combining history and a few examination steps achieved useful discrimination and is still in use [14]. And an international professional society agreed in a formal process on which features constitute the clinical diagnosis – tellingly, these are features from history and examination, not millimetre values from the scan [15].

5.2 The physical examination

What is examined: strength, sensation and reflexes in both legs, the mobility of the spine, the effect of bending and extending on the symptoms, balance in standing – and the foot pulses, to distinguish an arterial cause.

Two observations carry particular weight: a wide-based gait and unsteady standing with the eyes closed [11]. Sometimes it is also measured how long you can walk on a treadmill, once upright and once leaning slightly forward – the difference between the two says more than either figure alone [13].

In practice this means: no single test decides. A systematic review of nine studies concluded that none of the individual findings is strong enough on its own to confirm or exclude the diagnosis [13]. The diagnosis emerges from the whole picture.

5.3 When an MRI is needed

Magnetic resonance imaging shows the canal and the nerve roots in great detail and is the best available imaging method for this purpose [12]. The question is not whether it shows something – in most people over 60 it does – but whether the result changes the treatment.

A scan is useful above all when

• an operation is seriously under discussion – then it must be known exactly where and how tight it is;
• warning signs are present (see section 4);
• the symptoms do not fit the picture and another cause needs to be excluded.

It is not useful as a follow-up check when symptoms are stable. Imaging changes develop over years, your walking distance changes over weeks – and there is no close link between the two [10]. The more honest measure of progress is therefore the question of how far you can walk today.

5.4 Why no millimetre value makes the diagnosis

There is a widespread expectation that there must be a threshold: below so many millimetres it is stenosis. That expectation is disappointed. As mentioned, a systematic review found ten different measurement methods, and only four out of 63 treatment studies gave any numerical criterion at all for including their participants [9].

This is not a failing of radiology; it lies in the nature of the thing. How much room the nerve tissue needs differs from person to person, and the width changes with every movement. A scan is taken lying down – that is, in the position in which you feel best.

So: the diagnosis of "symptomatic spinal stenosis" is a clinical diagnosis. The scan confirms it or does not fit it – but it is made in the person, not in the image.

6. How it develops

6.1 Mostly it stays as it is

The fear that it will inevitably get worse until the wheelchair is the commonest reason for hasty decisions. The available long-term observations do not support it.

A Japanese group followed people with MRI-confirmed narrowing for an average of eleven years without surgery. At the end, symptoms had improved in about 30 %, were unchanged in about 30 % and had worsened in about 30 % [18]. The study is small – 34 people – but it is one of the few that observed for that long without an operation.

A Norwegian study followed 100 people over ten years, some operated on, some not. One incidental observation is notable: during the last six years of the follow-up period no clinically meaningful deterioration occurred – neither in the operated nor in the non-operated participants [19].

6.2 In whom it tends to get worse

In the same Japanese observation a pattern emerged: those whose symptoms increased already had a particularly small cross-sectional area of the canal at the start – on average below 50 square millimetres. Those who went on to have surgery usually had even less room at the outset [18].

That is not a prediction for the individual, but it is a useful pointer: with very marked narrowing it is worth following the course more closely and discussing the question of surgery earlier. With moderate narrowing, waiting is the obvious first step.

6.3 Why you may take your time

The most important finding for the decision is this: in the Norwegian study, people for whom conservative treatment did not help enough were operated on later – on average after three and a half months, in some cases after more than two years. Their outcome was essentially the same as that of the group operated on from the start [19].

This means you forfeit nothing by first exhausting non-surgical treatment. The door to surgery stays open. With a narrow spinal canal – unlike with the emergency signs in section 4 – there is no window that closes.

The one sentence to take away: with this condition, waiting is a treatment decision with a good reputation – not an omission.

7. What helps without surgery

7.1 Honesty first: the evidence is thin

Anyone reading this section should know what it rests on. The Cochrane review of non-surgical treatment from 2013 found only low or very low quality evidence for almost every measure examined [20]. The 2022 update assessed 23 additional trials and arrived at a somewhat clearer but still modest result [21]:

• There is moderate-quality evidence that a combined approach of manual therapy and exercise – with or without education – is effective and in the short term achieves considerably more than usual medical care or a community group exercise class.
• There is moderate-quality evidence that such a programme improves walking distance, and does so into the longer term.
• For all other non-surgical measures the evidence is insufficient to say anything reliable.

That is not a glowing balance sheet. But it is the honest one – and it does at least point in a direction: what works is a programme, not a single measure.

7.2 The goal is walking distance

With this condition the walking distance is the decisive measure – not the pain score, not the imaging finding. It can be measured, it means something concrete in daily life, and it can be improved.

The most informative study comes from Canada. 104 people with a confirmed diagnosis – average age 70.6 years, 84 % with leg symptoms for over a year, mean walking distance at the start 329 metres – received either a structured six-week programme or instructions for self-directed exercise. The programme comprised manual treatment, exercises, walking training with increasing load, and education about what is happening in the back and what can be done.

After six months the difference was large: the programme group walked on average 421 metres further than the comparison group (confidence interval 181 to 661 metres). 82 % of the programme group achieved an improvement they could feel, compared with 63 % of those exercising on their own. The advantage persisted to twelve months [22].

An American study of 259 people over 60 compared three approaches: medical care with medication and injections, a group exercise class at a community centre, or manual therapy with individually tailored exercise. After two months the third group was ahead, including on walking capacity. After six months the groups had converged – all three had improved [23].

And an older study compared two physiotherapy programmes with each other: one with manual treatment, exercise and body-weight-supported treadmill walking, the other with flexion exercises, treadmill walking and an inactive sham treatment. After six weeks considerably more people in the first group felt recovered; after one year it was 62 % versus 41 % [24].

This is how it can be summarised: a structured programme works better than loose advice, and the advantage is clearest in the first six months. Whether it persists beyond that varies from study to study – but every group in these studies improved its walking distance.

7.3 Bending as a tool, not as a posture

From section 2.3 follows a whole set of practical tricks that work immediately:

• Walking with a task for the hands – a shopping trolley, Nordic walking poles, or a rollator if the limitation is greater. All do the same thing: produce a slight forward lean that opens the canal.
• Plan breaks before the limit arrives. Someone with a bench every 200 metres walks further in total than someone who goes to the maximum and then needs a long recovery.
• Cycling or an exercise bike instead of walking when the walking distance is currently short. For endurance and leg strength it is equivalent – and it is usually pain-free.
• Relieving positions for acute phases: lying on your back with the legs bent and a cushion under the knees, or sitting and resting the upper body on the thighs.

The caveat matters. Bending is a tool for the moment, not a permanent posture. Anyone who walks around stooped all day gradually loses the ability to straighten up – and that ability is needed for balance, for standing up and for everything that happens overhead. The exercise programmes in the studies mentioned therefore always contained both: relief through bending and strengthening in an upright position.

7.4 Strength and fitness

The narrow canal cannot be widened by exercise – nobody can do that, and nobody claims to. What can be changed is everything else: how strong the legs are, how good the balance is, how much endurance you have, how much load you tolerate before the limit arrives.

This is not a side issue but often the most important thing in this age group. The typical person affected is over 65, has done less for months because of the walking distance and has lost muscle in the process – and loss of muscle worsens balance, walking speed and the risk of falling quite independently of the back. See our articles on strength training and muscle weakness in older age.

In practice that means: strengthen what carries the body (legs, buttocks, trunk), train balance, and build endurance by whichever route currently works – cycling, exercise bike, water, or walking in intervals.

7.5 Medication

With this condition medication is an aid to movement, not a treatment of the cause. And the evidence for it is weak: the updated review found no evidence of sufficient quality on drug treatment for a narrow spinal canal to support a clear recommendation [21].

What follows from that is not rejection but sobriety. A painkiller that allows you to take the walk and do the exercises has its place. A painkiller you have been taking for months without any change in your walking distance should be discussed. That applies particularly to stronger drugs: in older age they increase dizziness and the risk of falling – and falls are the real danger here.

7.6 The injection into the spinal canal

Injecting corticosteroid into the spinal canal (technical term: epidural injection) is a widespread treatment. It has been tested thoroughly.

The decisive study was an American double-blind trial with 400 participants. It compared corticosteroid together with a local anaesthetic against the local anaesthetic alone. After six weeks there was no meaningful difference – neither in everyday disability nor in leg pain [25]. Adding the corticosteroid therefore contributed nothing that the injection itself had not already provided.

The updated review confirms this and puts it as follows: the difference between corticosteroid and local anaesthetic alone was statistically detectable but not to an extent that would be noticeable for those affected [21].

In practice this means: the injection is not a treatment plan. It can make sense as a bridge when pain is so severe that exercise cannot get started. Anyone who has one should use the window afterwards to build up their loading – otherwise everything is as before after a few weeks.

7.7 What is not supported by evidence

For a whole range of measures that are offered – traction, braces and supports, ultrasound, electrotherapy, individual hands-on techniques without an accompanying exercise programme – the evidence is simply insufficient to claim an effect [20], [21].

"Not supported" does not mean "harmful". It means: these measures should not take the place that walking training, strengthening and education need – and they should not be what your nine sessions are spent on.

8. Surgery

8.1 What is done

The standard operation is called decompression – relieving pressure. Bone and thickened ligament are removed where it is too tight, so that the nerve roots have room again. Today this is usually done microsurgically through a small approach, with the aim of removing as little as possible of the stabilising structures.

Sometimes an additional fusion is proposed, in which two vertebrae are firmly joined with screws and rods. Whether this is necessary is the most contested question in the whole field – see section 8.3.

It is also worth knowing that the operation removes the narrowing, not the ageing. The discs and joints are the same after the procedure as before.

8.2 What it achieves – and what is difficult about these studies

Before the figures, a preliminary remark, without which these studies are read wrongly. In almost every comparison between surgery and conservative treatment, many participants switched groups: people allocated to the conservative group later had surgery after all. That is why there are always two analyses – one by original allocation, one by the treatment actually received. The first is methodologically cleaner, the second closer to what people experienced. They often reach different conclusions.

The largest study (SPORT, USA) enrolled 289 people in the randomised part. After two years, 67 % of the surgical group had had surgery – but so had 43 % of the conservative group. Analysed by allocation, there was an advantage for surgery in pain, but no meaningful difference in physical function or everyday disability. Analysed by treatment actually received, surgery was superior on all outcomes [26].

After eight years the same study looked like this: analysed by allocation there were no differences; analysed by treatment actually received, the initial advantage of surgery had evened out between the fourth and eighth year – in years six to eight no effect was detectable any more [27].

A Finnish study with 94 participants found an advantage for surgery after one year in disability, leg pain and back pain; after two years it had become smaller. Notably, in walking ability – measured and reported – there was no difference between the groups [28].

An American study compared surgery directly with physiotherapy: 169 people who were all already surgical candidates and had consented to the operation. After two years physical function was considerably better than at the start in both groups, and there was no difference between the groups. Here too many switched: 57 % of the physiotherapy group went on to have surgery [29].

The Cochrane review pooled five studies with 643 participants and reached a cautious conclusion: it cannot be said with confidence whether surgery or a conservative approach is better. It highlights a different point – side effects: complications occurred in 10 to 24 % of participants in the surgical groups, while none were reported in the conservative groups [30].

This is how it can be summarised: surgery works, and in the right people it works quickly. But it is not as superior to conservative treatment as the imaging report suggests, its advantage shrinks over the years, and it is the only one of the two options that carries a risk of complications. That makes it a good option – not a necessity.

8.3 Does a fusion have to be added?

This question mainly concerns people who also have a slipped vertebra. It is the only place in this text where two careful studies contradict each other – published in the same issue of the same journal.

The Swedish study examined 247 people aged between 50 and 80, with and without a slipped vertebra. Result: adding a fusion brought no advantage over decompression alone after two years – neither in disability nor in the six-minute walk test (397 versus 405 metres). The same held after five years. But the hospital stay lasted almost twice as long (7.4 versus 4.1 days), there was more blood loss and higher costs. About one in five people in each group needed further surgery [33].

The American study examined 66 people, all with a mild slipped vertebra. Here fusion was somewhat better for general physical quality of life after two years, and this advantage held to the fourth year. For back-related disability the difference was not confirmed. Striking was the number of repeat operations: 14 % in the fusion group versus 34 % after decompression alone [34].

The Cochrane review of surgical techniques assessed 24 studies with 2,352 participants and found, across all studies, no difference in pain and disability from adding a fusion – but more blood loss and longer operating times. For the interspinous spacers promoted as gentler, it found results similar to standard decompression but an around fourfold higher risk of needing another operation [31]. And the SPORT study on slipped vertebrae found a clear advantage for surgery over conservative treatment in the analysis by treatment actually received [32].

What you can do with this: this question is decided by the spinal surgeon together with you, not by physiotherapy. But it is a question you are entitled to ask – and a good answer is not "that is what we always do" but names a reason that fits your findings: the degree of slippage, the mobility of the affected level, how much bone has to be removed for the decompression.

8.4 Risks – particularly in older age

Decompression alone is a comparatively well-tolerated procedure. With the extent of the operation, however, the risk rises markedly. An analysis of 32,152 operations in older insured people in the USA showed the following for this same condition [35]:

Something else was striking: over the period studied the number of complex fusions increased fifteenfold, without the evidence improving correspondingly [35]. That is a reason to ask for the rationale when a fusion is proposed.

The general risks also include: injury to the covering of the spinal cord with leakage of nerve fluid, infection, bleeding, and the possibility that symptoms remain or return after years because the ageing continues.

8.5 Five questions for the decision

Because the studies give no universally valid answer, the decision is a personal one. These five questions help to order it:

• What exactly is stopping me? Not "how bad is the pain" but: what can I no longer do that matters to me? How far do I get today?
• Have I really exhausted non-surgical treatment? A structured programme over several weeks with walking training and strengthening – not just massage and heat, not just an injection.
• What has the course of the last few months been? A walking distance that stays stable argues for carrying on. One that is visibly shortening argues for a conversation with the surgical team.
• What am I bringing to the operation? Other illnesses, medication, smoking, strength and walking stability – all of that influences both the risk and the rebuilding afterwards.
• What am I expecting? The operation is good against the leg symptoms brought on by walking. It is not good against general back pain or morning stiffness.

9. After the operation

Many people expect strict prohibitions and a long period of taking it easy. The evidence points rather the other way. The Cochrane review of postoperative care assessed three studies with 373 participants and found: active rehabilitation is superior to usual aftercare – in the short term and still after twelve months, both for everyday function and for back pain. No adverse effects were reported in any of the studies [36].

A realistic course looks like this: in the first days and weeks, walk a lot, change position often, do not sit for long stretches. After that the actual rebuilding begins – strength for legs and trunk, balance, endurance, and step by step the movements of daily life. Here too the walking distance is the best measure: it should increase over the weeks.

Two points that often surprise people. First: the leg symptoms usually improve quickly, while strength and confidence take longer – anyone who has walked little for months has lost muscle, and that does not come back with the operation. Second: back pain that was already there often remains. That is not a sign that something has gone wrong.

The instructions of the operating clinic are always binding. They know the details of the procedure – if they say something different from this text, their instructions apply.

10. A narrow canal in the neck – here the opposite applies

Everything said so far concerns the lower back. In the neck the situation is different, and this section is the reason why this text addresses it explicitly.

In the neck the canal contains not a bundle of individual roots but the spinal cord itself. If it is permanently compressed by the same ageing processes, a disease in its own right develops: degenerative cervical myelopathy. "Cervical" means relating to the neck, "myelopathy" a disease of the spinal cord.

It announces itself differently from narrowing in the lower back – often gradually and without severe pain [38]:

• Clumsy hands – buttons, zips, keys, handwriting that changes.
• Unsteady walking, balance problems, more frequent falls.
• Symptoms in both arms, or in arms and legs at the same time.
• Later, changes in bladder and bowel.

The decisive difference lies in the approach. Whereas with a narrow lumbar canal you may wait calmly, that does not apply here: the international guideline recommends surgical decompression for moderate and severe myelopathy. For mild disease either is defensible – surgery, or supervised rehabilitation with close monitoring so that deterioration is not missed [37]. The reason is that damage to the spinal cord recovers less well than irritation of nerve roots.

Important: if you notice clumsiness of the hands, increasing unsteadiness when walking or symptoms in both arms, do not wait – even if it barely hurts. This condition is frequently recognised late [38], and the timing of treatment influences the outcome.

11. What you can do yourself

Six things that influence the course and are in your hands:

• Make walking distance your own measure. Note once a week how far you can walk without stopping. That is more informative than any scan [10] and shows you whether what you are doing is working.
• Keep walking, in stages. Better four times 200 metres with a bench in between than once to the absolute limit. The total counts, and the total can be increased [22].
• Get stronger. Legs, buttocks, trunk – two to three times a week. It does not improve the canal, but it improves everything else.
• Train your balance. Because unsteady walking is part of this condition and falls are the greater danger, not the narrow canal.
• Choose a form of movement that currently works. Cycling, an exercise bike or water if walking is hard. The body does not care where the endurance comes from.
• Keep an eye on your weight and, if you smoke, stop. Both affect how much you can tolerate and – if it does come to surgery – how you heal.

And a word about fear, because it so often plays a part: the worry that walking "squeezes the nerve further" is understandable and nonetheless unfounded. The symptoms arise from a temporary undersupply, not from destruction [4]. Walking to your own limit and then pausing is exactly right.

12. Where, how often and how long treatment takes place

In Switzerland a medical prescription covers nine sessions [39]. For a narrow spinal canal this is often enough for the first stage: making sense of it, introducing relieving positions and walking strategies, setting up the home programme, starting to build up loading. If the limitation persists, or after an operation, a second prescription follows.

At the beginning appointments are closer together, because a lot is being adjusted. Later they become less frequent and the home programme carries more weight.

The decisive point is the same as everywhere: what happens between appointments decides the outcome. The programmes that worked in the studies were programmes to do yourself with professional steering – not treatments you receive [22].

And a criterion for the interim review: after four to six weeks something should have shifted – more metres, fewer breaks, less unsteadiness. If nothing shifts, we change the approach or recommend further assessment. What does not make sense is carrying on unchanged because there are sessions left.

13. Eight common misunderstandings

"A narrow canal on the scan explains my symptoms."
Not necessarily. In a population study only 17.5 % of people with marked narrowing also had the matching symptoms [6]. Only the agreement of scan, history and examination makes a diagnosis.

"The narrower it is, the worse the pain."
A Swiss cohort study found no useful association between MRI measurements and pain intensity [10]. The narrowing says something about the canal, not about you.

"This will inevitably get worse and worse."
Over ten years it stayed the same in about a third and improved in a third [18]. And in a Norwegian ten-year study no meaningful deterioration occurred during the last six years [19].

"If I do not operate soon it will be too late."
People treated conservatively first and operated on later had essentially the same outcome as those operated on early [19]. This does not apply to the emergency signs in section 4, and not to the neck.

"Walking damages the nerve."
The symptoms arise from a temporary undersupply of the nerve roots that disappears again when you stop [4]. Walking to your limit does no damage.

"Physiotherapy can do nothing about a narrowing."
It does not widen the canal. It does improve walking distance: in one trial the programme group walked on average 421 metres further than the comparison group after six months [22].

"An injection solves the problem."
In a double-blind trial with 400 participants, adding corticosteroid brought no meaningful advantage over the local anaesthetic alone [25]. As a bridge it can make sense; as a plan it does not.

"If we are operating, let us do it properly – with a fusion."
In the Swedish trial the added fusion brought no advantage but clearly lengthened the hospital stay [33], and with the extent of the procedure the risk of complications rises [35]. With a slipped vertebra the balance comes out differently in part [34] – that needs to be discussed case by case.

14. When to get in touch

Go to the emergency department immediately:

• Bladder or bowel function has changed – unable to pass urine, unable to hold urine or stool, no longer feeling the bladder fill.
• Numbness in the saddle area – perineum, genitals, inner thighs.
• New severe symptoms or rapidly increasing weakness in both legs.

Seek medical assessment within a few days:

• New or increasing weakness in the leg, especially if the foot catches.
• A walking distance that shortens markedly within a few weeks.
• Unbearable pain despite medication, no sleep at night.
• Clumsy hands, increasing unsteadiness when walking, or symptoms in both arms – see section 10.
• Fever, unintended weight loss, a history of cancer.
• Cold, pale legs or absent foot pulses.

Raise it in physiotherapy:

• Your walking distance has not improved after four to six weeks.
• You avoid outings because you do not know whether there will be somewhere to sit.
• You feel unsteady on your feet or have fallen recently.
• You are facing the question of whether to have surgery and would like to sort out the arguments.
• You have had surgery and do not know how to plan the rebuilding.

What to expect in our practice: first, making sense of it – do the symptoms fit neurogenic claudication, could the arteries or the hip be involved, are there warning signs? Then an honest account of the likely course, because that usually reduces the burden most. After that the work: relieving positions and walking strategies for daily life, a home programme with clear dosing, strength and balance training, and walking training built up in stages. We measure the walking distance over time and check after four to six weeks whether things are moving forward. If the question of surgery is on the table, we prepare it with you – the decision is made together with your doctor, but it is easier when it is clear what the operation can and cannot deliver.

15. In summary

"Spinal stenosis" describes a narrow spinal canal – a finding that is very common in older people and causes no symptoms in most of them. It becomes a disease only when the typical pattern is added: leg symptoms that come on with walking and standing and disappear again on sitting or bending forward.

The reason for that pattern is both mechanical and circulatory: straightening up narrows the canal, bending widens it, and when walking the nerve roots need more oxygen than reaches them through the narrow canal. That is why walking does no harm – it only shows where the limit currently lies.

The course is mostly stable. Over ten years it stayed the same in about a third and improved in a third. And those who are operated on later lose nothing by having waited. The evidence for non-surgical treatment is not glorious, but one point is well established: a structured programme of walking training, strengthening and education clearly improves walking distance – and walking distance is what daily life is about.

Surgery relieves the nerve roots and works quickly and well in the right people. Its advantage over conservative treatment shrinks over the years, and it is the only one of the two options carrying a risk of complications. It is therefore a good option, not a necessity – except with the rare emergency signs, and in the neck, where different rules apply.

The most useful question is therefore not "how narrow is it?" but: how far do I get today, and what is the next step to getting further?

If you would like to experience how much the course depends on the decisions of the first few weeks: our learning game Rückenwerk lets you make exactly those decisions over twelve weeks and shows where they lead.

References

All Digital Object Identifiers (DOIs) were checked individually against the Crossref register. The links in the reference list lead via the DOI service to the publishers' pages. Some of these are located outside Switzerland and the EU. When you click, your IP address is transmitted to the respective provider – this does not happen on our own site.

[1] Katz JN, Zimmerman ZE, Mass H, Makhni MC. Diagnosis and Management of Lumbar Spinal Stenosis: A Review. JAMA. 2022;327(17):1688–1699. https://doi.org/10.1001/jama.2022.5921

[2] Lurie J, Tomkins-Lane C. Management of lumbar spinal stenosis. BMJ. 2016;352:h6234. https://doi.org/10.1136/bmj.h6234

[3] Genevay S, Atlas SJ. Lumbar Spinal Stenosis. Best Practice & Research Clinical Rheumatology. 2010;24(2):253–265. https://doi.org/10.1016/j.berh.2009.11.001

[4] Porter RW. Spinal Stenosis and Neurogenic Claudication. Spine. 1996;21(17):2046–2052. https://doi.org/10.1097/00007632-199609010-00024

[5] Kalichman L, Cole R, Kim DH, Li L, Suri P, Guermazi A, Hunter DJ. Spinal stenosis prevalence and association with symptoms: the Framingham Study. The Spine Journal. 2009;9(7):545–550. https://doi.org/10.1016/j.spinee.2009.03.005

[6] Ishimoto Y, Yoshimura N, Muraki S, et al. Associations between radiographic lumbar spinal stenosis and clinical symptoms in the general population: the Wakayama Spine Study. Osteoarthritis and Cartilage. 2013;21(6):783–788. https://doi.org/10.1016/j.joca.2013.02.656

[7] Jensen RK, Jensen TS, Koes B, Hartvigsen J. Prevalence of lumbar spinal stenosis in general and clinical populations: a systematic review and meta-analysis. European Spine Journal. 2020;29(9):2143–2163. https://doi.org/10.1007/s00586-020-06339-1

[8] Brinjikji W, Luetmer PH, Comstock B, et al. Systematic Literature Review of Imaging Features of Spinal Degeneration in Asymptomatic Populations. American Journal of Neuroradiology. 2015;36(4):811–816. https://doi.org/10.3174/ajnr.A4173

[9] Steurer J, Roner S, Gnannt R, Hodler J. Quantitative radiologic criteria for the diagnosis of lumbar spinal stenosis: a systematic literature review. BMC Musculoskeletal Disorders. 2011;12:175. https://doi.org/10.1186/1471-2474-12-175

[10] Burgstaller JM, Schüffler PJ, Buhmann JM, et al. Is There an Association Between Pain and Magnetic Resonance Imaging Parameters in Patients With Lumbar Spinal Stenosis? Spine. 2016;41(17):E1053–E1062. https://doi.org/10.1097/BRS.0000000000001544

[11] Suri P, Rainville J, Kalichman L, Katz JN. Does This Older Adult With Lower Extremity Pain Have the Clinical Syndrome of Lumbar Spinal Stenosis? JAMA. 2010;304(23):2628–2636. https://doi.org/10.1001/jama.2010.1833

[12] de Schepper EIT, Overdevest GM, Suri P, et al. Diagnosis of Lumbar Spinal Stenosis: An Updated Systematic Review of the Accuracy of Diagnostic Tests. Spine. 2013;38(8):E469–E481. https://doi.org/10.1097/BRS.0b013e31828935ac

[13] Cook CJ, Cook CE, Reiman MP, Joshi AB, Richardson W, Garcia AN. Systematic review of diagnostic accuracy of patient history, clinical findings, and physical tests in the diagnosis of lumbar spinal stenosis. European Spine Journal. 2020;29(1):93–112. https://doi.org/10.1007/s00586-019-06048-4

[14] Konno S, Kikuchi S, Tanaka Y, et al. A diagnostic support tool for lumbar spinal stenosis: a self-administered, self-reported history questionnaire. BMC Musculoskeletal Disorders. 2007;8:102. https://doi.org/10.1186/1471-2474-8-102

[15] Tomkins-Lane C, Melloh M, Lurie J, et al. ISSLS Prize Winner: Consensus on the Clinical Diagnosis of Lumbar Spinal Stenosis. Spine. 2016;41(15):1239–1246. https://doi.org/10.1097/BRS.0000000000001476

[16] Todd NV. Guidelines for cauda equina syndrome. Red flags and white flags. Systematic review and implications for triage. British Journal of Neurosurgery. 2017;31(3):336–339. https://doi.org/10.1080/02688697.2017.1297364

[17] Hoeritzauer I, Wood M, Copley PC, Demetriades AK, Woodfield J. What is the incidence of cauda equina syndrome? A systematic review. Journal of Neurosurgery: Spine. 2020;32(6):832–841. https://doi.org/10.3171/2019.12.SPINE19839

[18] Minamide A, Yoshida M, Maio K. The natural clinical course of lumbar spinal stenosis: a longitudinal cohort study over a minimum of 10 years. Journal of Orthopaedic Science. 2013;18(5):693–698. https://doi.org/10.1007/s00776-013-0435-9

[19] Amundsen T, Weber H, Nordal HJ, Magnaes B, Abdelnoor M, Lilleâs F. Lumbar Spinal Stenosis: Conservative or Surgical Management? A Prospective 10-Year Study. Spine. 2000;25(11):1424–1436. https://doi.org/10.1097/00007632-200006010-00016

[20] Ammendolia C, Stuber KJ, Rok E, et al. Nonoperative treatment for lumbar spinal stenosis with neurogenic claudication. Cochrane Database of Systematic Reviews. 2013;(8):CD010712. https://doi.org/10.1002/14651858.CD010712

[21] Ammendolia C, Hofkirchner C, Plener J, et al. Non-operative treatment for lumbar spinal stenosis with neurogenic claudication: an updated systematic review. BMJ Open. 2022;12(1):e057724. https://doi.org/10.1136/bmjopen-2021-057724

[22] Ammendolia C, Côté P, Southerst D, et al. Comprehensive Nonsurgical Treatment Versus Self-directed Care to Improve Walking Ability in Lumbar Spinal Stenosis: A Randomized Trial. Archives of Physical Medicine and Rehabilitation. 2018;99(12):2408–2419.e2. https://doi.org/10.1016/j.apmr.2018.05.014

[23] Schneider MJ, Ammendolia C, Murphy DR, et al. Comparative Clinical Effectiveness of Nonsurgical Treatment Methods in Patients With Lumbar Spinal Stenosis: A Randomized Clinical Trial. JAMA Network Open. 2019;2(1):e186828. https://doi.org/10.1001/jamanetworkopen.2018.6828

[24] Whitman JM, Flynn TW, Childs JD, et al. A Comparison Between Two Physical Therapy Treatment Programs for Patients With Lumbar Spinal Stenosis: A Randomized Clinical Trial. Spine. 2006;31(22):2541–2549. https://doi.org/10.1097/01.brs.0000241136.98159.8c

[25] Friedly JL, Comstock BA, Turner JA, et al. A Randomized Trial of Epidural Glucocorticoid Injections for Spinal Stenosis. New England Journal of Medicine. 2014;371(1):11–21. https://doi.org/10.1056/NEJMoa1313265

[26] Weinstein JN, Tosteson TD, Lurie JD, et al. Surgical versus Nonsurgical Therapy for Lumbar Spinal Stenosis. New England Journal of Medicine. 2008;358(8):794–810. https://doi.org/10.1056/NEJMoa0707136

[27] Lurie JD, Tosteson TD, Tosteson A, et al. Long-term Outcomes of Lumbar Spinal Stenosis: Eight-Year Results of the Spine Patient Outcomes Research Trial (SPORT). Spine. 2015;40(2):63–76. https://doi.org/10.1097/BRS.0000000000000731

[28] Malmivaara A, Slätis P, Heliövaara M, et al. Surgical or Nonoperative Treatment for Lumbar Spinal Stenosis? A Randomized Controlled Trial. Spine. 2007;32(1):1–8. https://doi.org/10.1097/01.brs.0000251014.81875.6d

[29] Delitto A, Piva SR, Moore CG, et al. Surgery Versus Nonsurgical Treatment of Lumbar Spinal Stenosis: A Randomized Trial. Annals of Internal Medicine. 2015;162(7):465–473. https://doi.org/10.7326/M14-1420

[30] Zaina F, Tomkins-Lane C, Carragee E, Negrini S. Surgical versus non-surgical treatment for lumbar spinal stenosis. Cochrane Database of Systematic Reviews. 2016;(1):CD010264. https://doi.org/10.1002/14651858.CD010264.pub2

[31] Machado GC, Ferreira PH, Yoo RIJ, et al. Surgical options for lumbar spinal stenosis. Cochrane Database of Systematic Reviews. 2016;(11):CD012421. https://doi.org/10.1002/14651858.CD012421

[32] Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical versus Nonsurgical Treatment for Lumbar Degenerative Spondylolisthesis. New England Journal of Medicine. 2007;356(22):2257–2270. https://doi.org/10.1056/NEJMoa070302

[33] Försth P, Ólafsson G, Carlsson T, et al. A Randomized, Controlled Trial of Fusion Surgery for Lumbar Spinal Stenosis. New England Journal of Medicine. 2016;374(15):1413–1423. https://doi.org/10.1056/NEJMoa1513721

[34] Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus Fusion versus Laminectomy Alone for Lumbar Spondylolisthesis. New England Journal of Medicine. 2016;374(15):1424–1434. https://doi.org/10.1056/NEJMoa1508788

[35] Deyo RA, Mirza SK, Martin BI, Kreuter W, Goodman DC, Jarvik JG. Trends, Major Medical Complications, and Charges Associated With Surgery for Lumbar Spinal Stenosis in Older Adults. JAMA. 2010;303(13):1259–1265. https://doi.org/10.1001/jama.2010.338

[36] McGregor AH, Probyn K, Cro S, et al. Rehabilitation following surgery for lumbar spinal stenosis. Cochrane Database of Systematic Reviews. 2013;(12):CD009644. https://doi.org/10.1002/14651858.CD009644.pub2

[37] Fehlings MG, Tetreault LA, Riew KD, et al. A Clinical Practice Guideline for the Management of Patients With Degenerative Cervical Myelopathy: Recommendations for Patients With Mild, Moderate, and Severe Disease and Nonmyelopathic Patients With Evidence of Cord Compression. Global Spine Journal. 2017;7(3 Suppl):70S–83S. https://doi.org/10.1177/2192568217701914

[38] Davies BM, Mowforth OD, Smith EK, Kotter MRN. Degenerative cervical myelopathy. BMJ. 2018;360:k186. https://doi.org/10.1136/bmj.k186

[39] Verordnung des EDI über Leistungen in der obligatorischen Krankenpflegeversicherung (KLV), SR 832.112.31, Art. 5 (Physiotherapie). Zusammengefasst in: FMH. Verordnung von Physiotherapie im KVG-Bereich – Frequently Asked Questions. Stand 31.10.2022. fmh.ch (PDF)