Spinal stenosis is narrowing of the space the nerves travel through. The word describes a finding on a scan, not a single disease — and what is doing the narrowing determines what will help.
What Is Actually Narrowing
Most patients picture a disc pressing inward. That is one contributor among several, and often not the main one.
Dr. María Alejandra De La Peña, an anaesthesiologist fellowship-trained in interventional pain management at Harvard's Beth Israel Deaconess, describes a case where the imaging made the point directly. Reviewing the contrast spread on a lumbar epidural, she observed the ligament crossing the expected anatomical line — evidence that “part of his lumbar stenosis problem is caused by ligamentum flavum hypertrophy.”
The ligamentum flavum sits at the back of the spinal canal. As it thickens with age and load, it buckles inward and takes up space the nerves need. Nothing about that involves a disc.
The usual contributors, generally in combination:
- Ligamentum flavum hypertrophy — thickening from behind
- Facet arthropathy and bone spurs — osteophytes narrowing the canal and the foramen
- Disc bulging from the front
- Spondylolisthesis — one vertebra slipping on another
De La Peña notes that osteophytes are “very common in these areas, especially with age. We start developing bone spurs around and their level of stenosis.”
Central, Lateral Recess and Foraminal
Where the narrowing sits changes the symptoms.
Central stenosis narrows the main canal and typically produces neurogenic claudication — leg pain and heaviness on walking that eases on sitting or leaning forward.
Lateral recess stenosis affects the nerve as it turns to exit. De La Peña notes this is “very common after having multi-level laminectomy”, where facet arthropathy and bone spurs develop and contribute to the narrowing.
Foraminal stenosis compresses the root at the exit. In one case she describes it as “completely occluded” — and, crucially, notes that this “is the explanation of his symptoms.” The finding matched the complaint.
The Shopping Trolley Sign
Stenosis has a symptom pattern distinctive enough to suggest the diagnosis before imaging.
Pain and heaviness in the legs on walking, which eases when sitting or leaning forward over something. People describe walking further in a supermarket leaning on a trolley than they can walk down the street.
The reason is mechanical: flexion opens the canal, extension closes it. Which is also why a stenotic patient is more comfortable cycling than walking.
Pain that is worse standing and better sitting suggests stenosis. Pain worse sitting and better standing suggests a disc.
Treatment, In Order
1. Activity and Physical Therapy
Flexion-based exercise, walking tolerance work, core and hip strengthening. This does not widen the canal; it improves how much the patient can do within it, which for many is the practical goal.
2. Epidural Steroid Injection
Stenosis is among the conditions De La Peña names as an indication for lumbar epidural injection, alongside nerve root impingement, disc herniation and discogenic pain.
The aim is inflammation around the compressed nerve rather than the narrowing itself. Her framing of purpose applies particularly well here: “reducing inflammation, improved lifestyle, improved functionality of the patient.” For stenosis, function — how far the patient can walk — is the measure that matters most.
Ready to put this into practice?
Explore Empire's hands-on, CME-accredited Pain Management & Interventional Therapies courses — live patients, expert faculty, and ongoing mentorship.
The approach follows the pattern. Back and leg pain together points to an interlaminar approach; leg pain alone to a transforaminal one targeting the specific root. Where the anatomy is distorted by previous surgery, the choice changes — set out in epidural steroid injections.
3. Surgery
Decompression is the definitive option where symptoms are severe, walking distance is meaningfully limited, or there is progressive neurological deficit.
It is worth understanding what follows. De La Peña describes the post-laminectomy picture candidly: scar tissue and osteophytes are “quite common”, and after multi-level surgery patients develop facet arthropathy and bone spurs that contribute to renewed narrowing, with weakened discs that continue to protrude. Her assessment of one such case: “he might have good initial response from this surgery, but over time with the degeneration he will have recurrence.”
That is not an argument against surgery. It is an argument for expecting the spine to keep degenerating afterwards.
Why Injections Get Harder After Surgery
Previous decompression changes what can be offered, which surprises patients who assume the options stay open.
With the lamina removed, the interlaminar route is not available — the anatomy is distorted and, in De La Peña's words, “there is a high risk of having intrathecal uptake.” A bilateral transforaminal approach is used instead.
And in patients fused to L5-S1 who have developed adhesions, a caudal approach with a catheter can help release scarred tissue.
Bone spurs add a practical difficulty she describes from a live case: “sometimes you can see them on x-ray, sometimes you don't, but you can feel them.” The procedure is genuinely harder in a degenerative spine, which is worth knowing when the injection takes longer than expected.
What Stenosis Treatment Cannot Do
No injection widens a narrowed canal. No exercise reverses ligament thickening or removes an osteophyte.
Non-surgical treatment for stenosis manages the consequences of narrowing — inflammation, deconditioning, walking tolerance. That is a legitimate and often sufficient goal, but it is a different claim from correcting the anatomy, and a clinic that blurs the two is overselling.
Frequently Asked Questions
What causes spinal stenosis?
Usually several things together: thickening of the ligamentum flavum buckling inward, facet arthropathy and bone spurs, disc bulging, and sometimes spondylolisthesis. Faculty note osteophytes are very common with age at the level of the stenosis, and describe cases where ligament hypertrophy was visibly responsible for part of the narrowing.
Why can I walk further leaning on a trolley?
Because flexion opens the spinal canal and extension closes it. Leaning forward creates space, which is why patients with stenosis often walk further in a supermarket than down the street, and are more comfortable cycling than walking.
Do epidural steroid injections help spinal stenosis?
Stenosis is among the recognised indications for lumbar epidural injection. The injection targets inflammation around the compressed nerve rather than the narrowing itself, so the realistic aim is improved function and walking tolerance rather than correcting the anatomy.
Does spinal stenosis always need surgery?
No. Decompression is considered where symptoms are severe, walking distance is meaningfully limited, or there is progressive neurological deficit. Many patients manage with activity, physical therapy and injections.
Can stenosis come back after surgery?
Yes, and faculty describe it as the expected course in a degenerative spine rather than a failure. After multi-level laminectomy, facet arthropathy, scar tissue and bone spurs commonly develop and contribute to renewed narrowing.
Disclaimer
This article is educational and is not medical advice. It does not establish a clinician-patient relationship. Treatment decisions about spinal stenosis are individual and should be made with a qualified clinician who has examined you and reviewed your imaging.
Claim Your Prize!