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Grade 1 Spondylolisthesis and Meyerding Grades I–V: What the Slip Grade Means

Written by Ifije Ohiorhenuan, MD, PhD — Board-Certified Spine Surgeon. Last updated 2026-06-20.

Grade 1 spondylolisthesis means one vertebra has slipped forward by less than 25% compared with the bone below it, and by itself it does not automatically mean you need surgery or that your spine is unstable.

If you saw the words “Grade 1 spondylolisthesis,” “anterolisthesis,” or “Meyerding Grade I” on an X-ray or MRI report, it can sound alarming. Many people picture a bone sliding out of place. In most cases, Grade 1 is the mildest category. The more important question is whether the slip matches your symptoms, pinches a nerve, or moves too much.

What Does “Grade 1 Spondylolisthesis” Mean?

Spondylolisthesis means one vertebra, which is one of the bones in your spine, has slipped compared with the vertebra below it.

Anterolisthesis means the vertebra has slipped forward.

Many spine reports use “spondylolisthesis” and “anterolisthesis” in a similar way when they are describing a forward slip. The exact wording can vary from one radiologist to another.

Grade 1 spondylolisthesis means the slip is less than 25% of the width of the vertebral body. The vertebral body is the large front part of the spinal bone.

Grade 1 is the mildest Meyerding grade.

Grade 1 spondylolisthesis means the slip is small by measurement. It does not automatically tell us how much pain you should have, whether a nerve is pinched, or whether surgery is needed.

In my practice, I tell patients that Grade 1 is a measurement, not a diagnosis of how much pain they should have.

For a broader overview, see Spondylolisthesis: When the Bones Slip.

The Meyerding Classification: Grades I Through V

The Meyerding classification is a grading system for spondylolisthesis. It measures how far one vertebral body has slipped forward compared with the vertebra below it.

You may see the grade on a standing X-ray, an MRI, which is a scan that uses magnets to show soft tissues and nerves, or a CT scan, which is a scan that uses X-rays to show bone detail.

Meyerding Grade Amount of Slip Plain-English Meaning
Grade I 0–25% Mild slip
Grade II 25–50% Moderate slip
Grade III 50–75% More significant slip
Grade IV 75–100% Severe slip
Grade V More than 100% Spondyloptosis; the upper vertebra has slipped completely beyond the one below

Spondyloptosis means the upper vertebra has slipped more than 100% forward. This is Grade V. It is uncommon and is very different from the typical Grade 1 finding many people see on reports.

Image/diagram suggestion

Create a simple side-view diagram of two lumbar vertebrae showing:

  • Normal alignment
  • Grade I slip: less than 25%
  • Grade II: 25–50%
  • Grade III: 50–75%
  • Grade IV: 75–100%
  • Grade V: greater than 100% / spondyloptosis

Add this note below the diagram:

The grade measures how far the bone has slipped, not how much pain a person should have.

Does a Higher Grade Always Mean More Pain?

No.

A higher grade can be more important from a structure standpoint. But the grade does not always match pain severity.

Some people with Grade 1 spondylolisthesis have a lot of symptoms. This can happen if the slip narrows the spaces for the nerves or adds to stenosis, which means narrowing around the spinal canal or nerve pathways.

Other people with low-grade slips have little pain or no symptoms.

Pain can come from many places, including:

  • Discs, which are the cushions between the vertebrae
  • Facet joints, which are small joints in the back of the spine
  • Nerves
  • Muscles
  • The sacroiliac joint, which is the joint between the spine and pelvis
  • Other sources outside the spine

The Meyerding grade measures alignment. It does not measure inflammation, nerve irritation, instability, or how the finding fits your symptoms.

What Doctors Look For Besides the Slip Grade

The slip grade is only one part of the story. A small slip can matter if it affects a nerve. A larger slip may cause fewer symptoms if the nerves still have enough room.

What I look for on MRI is not just the slip. I look for whether that slip is crowding the nerves or narrowing the spaces where the nerves travel.

Is There Nerve Compression?

Nerve compression means a nerve is being squeezed or crowded.

A slip can sometimes contribute to several types of narrowing:

If a nerve root is irritated, you may feel sciatica. Sciatica means pain, tingling, numbness, or weakness that travels from the low back or buttock into the leg along a nerve path. Learn more in Sciatica: Causes, Diagnosis, and the Treatment Path.

The finding matters most when the patient’s symptoms match the level and side of the nerve compression.

Is the Slip Stable or Mobile?

A slip may look different on a standing X-ray than it does on a lying-down MRI.

Instability usually means abnormal motion between two vertebrae. It does not mean that every small slip is dangerous.

MRI shows anatomy very well. But MRI is usually done while you are lying still. It may not fully show whether the slipped level moves too much when you stand, bend, or extend.

Flexion-extension X-rays are standing X-rays taken while you bend forward and backward. They can help show whether there is abnormal motion when that question matters.

If I am worried about motion at the slipped level, I may look beyond the MRI and consider standing or flexion-extension X-rays.

Is It Degenerative or Isthmic?

The cause of the slip matters.

Degenerative spondylolisthesis means the slip is related to wear-and-tear changes in the disc and facet joints. This is more common in older adults. It often happens at L4-L5. L4-L5 means the level between the fourth and fifth lumbar vertebrae in the low back.

Isthmic spondylolisthesis means the slip is related to a defect or stress fracture in the pars interarticularis. The pars interarticularis is a small bridge of bone in the back part of the vertebra. Isthmic slips often happen at L5-S1. L5-S1 means the level between the lowest lumbar vertebra and the sacrum, which is the bone at the base of the spine.

Degenerative and isthmic spondylolisthesis both involve a slip. But they are not the same problem. Their patterns and treatment choices can differ.

For more on the condition itself, see Spondylolisthesis: When the Bones Slip.

Are the Symptoms Matching the Imaging?

Back pain alone is different from leg pain, numbness, weakness, or trouble walking.

A Grade 1 slip at L4-L5 may matter more if you have symptoms that match L4 or L5 nerve compression. But the report phrase alone cannot prove the pain source.

A radiology report describes what is seen on the scan. It does not know your exact pain pattern, strength exam, reflexes, or walking limits.

Grade 1 Spondylolisthesis: Is It Serious?

Grade 1 is generally considered low-grade. It is the mildest Meyerding category.

Many people with Grade 1 spondylolisthesis are treated without surgery. That is especially true when there is no progressive weakness, severe nerve compression, or disabling limitation.

But Grade 1 is not automatically “nothing.” Its seriousness depends on the full picture, including:

  • Your symptoms
  • Your neurologic findings, meaning strength, feeling, reflexes, and walking function
  • Whether nerves are compressed
  • Whether there is spinal stenosis
  • Whether the slip is stable or mobile
  • Whether the slip is changing over time
  • How much the symptoms limit your life

A Grade 1 slip with mild or no symptoms is very different from a Grade 1 slip with progressive weakness or severe stenosis.

Grade 1 is the mildest category, but the grade is only one part of the picture.

Does Grade 1 Spondylolisthesis Get Worse?

Some Grade 1 slips remain stable over time.

Some can progress. The risk is not the same for everyone. It can depend on:

  • Age
  • The cause of the slip
  • The spinal level
  • Disc wear
  • Facet joint arthritis
  • Whether the slip is degenerative or isthmic
  • Whether the level shows abnormal motion

Not every Grade 1 slip needs repeated imaging. Follow-up imaging may be considered when symptoms change, new neurologic findings appear, or a clinician is monitoring known or suspected instability.

A change in symptoms often matters more than the number alone.

How Spondylolisthesis Is Usually Treated

This section is a high-level overview. It is not a personal treatment plan.

Many low-grade slips are first treated without surgery. Common options may include:

  • Activity changes to reduce painful positions or loads
  • Physical therapy focused on core strength, hip strength, flexibility, and movement mechanics
  • Anti-inflammatory medicines when appropriate and approved by the patient’s clinician
  • Injections in selected cases, especially when nerve irritation or stenosis is suspected
  • Surgery in selected cases when symptoms are persistent and disabling, neurologic deficits are present, or instability or stenosis is significant

Anti-inflammatory medicines are medicines that reduce inflammation and pain. They may not be safe for everyone.

Injections usually mean placing medicine near an irritated nerve or painful spinal area to reduce inflammation. They are not the right choice for every person.

I do not recommend treatment based on the word “spondylolisthesis” alone. I look at the patient’s pain pattern, neurologic exam, imaging, and how much the symptoms are limiting life.

Treatment is based on the patient’s symptoms and exam, not the Meyerding grade alone.

For a deeper treatment overview, see Spondylolisthesis: When the Bones Slip.

Why Your MRI Report May Sound Scarier Than the Finding Is

Radiology reports use technical language. Words like “listhesis,” “spondylolisthesis,” and “anterolisthesis” can sound worse than the measurement actually is.

Listhesis means slippage. It describes alignment.

Your report may also list several degenerative findings. Degenerative means related to wear-and-tear or age-related change. These findings are common on spine imaging, even in some people without pain.

The key question is not, “Does the report list abnormalities?” Many reports do.

The better question is:

Which findings, if any, explain your symptoms?

For help with MRI wording, see How to Read Your Spine MRI Report.

If you are confused by similar-sounding terms, see Spondylosis vs. Spondylolisthesis vs. Spondylolysis: The Three “Spondy” Words.

If your report says the vertebra slipped backward instead of forward, see Retrolisthesis: When the Vertebra Slips Backward.

When to Seek Urgent Medical Care

This article and SpineClarity’s written MRI/case review are not for emergencies.

Seek urgent medical care now if you have:

  • New or worsening leg weakness
  • Numbness in the groin, genitals, buttocks, or saddle area
  • Loss of bladder control
  • Loss of bowel control
  • New trouble starting urination with severe back or leg symptoms
  • Rapidly worsening numbness, weakness, or walking trouble
  • Fever, chills, or feeling very ill with severe back pain
  • Severe back pain with infection risk, such as IV drug use, immune suppression, recent spine procedure, or active infection elsewhere
  • Severe back pain with a known history of cancer or unexplained weight loss
  • Severe pain after a major fall, accident, or trauma
  • Back pain with possible fracture risk, especially in older adults or people with osteoporosis or long-term steroid use

Cauda equina syndrome is a spine emergency where nerves at the bottom of the spinal canal are severely compressed. It can cause bladder or bowel changes, saddle numbness, leg weakness, or severe nerve symptoms.

If symptoms are rapidly worsening, do not wait for an online review. Possible cauda equina symptoms require immediate emergency evaluation.

Learn more in Cauda Equina Syndrome: The Spine Emergency Patients Need to Recognize.

When a Written MRI/Case Review Can Help

If your report says “Grade 1 spondylolisthesis,” “anterolisthesis,” or “Meyerding Grade I” and you are not sure whether it explains your symptoms, SpineClarity can help.

A board-certified spine surgeon can review your symptoms, MRI report, and relevant records and provide a plain-language written interpretation with a suggested next-step category.

This is not emergency care and does not replace an in-person physician relationship.

Frequently Asked Questions

What is Grade 1 spondylolisthesis?

Grade 1 spondylolisthesis means one vertebra has slipped forward less than 25% compared with the vertebra below it. It is the mildest Meyerding grade.

Is Grade 1 spondylolisthesis serious?

It can be mild, but the grade alone does not decide seriousness. The important issues are symptoms, nerve compression, neurologic findings, stability, and whether the slip is changing.

Does Grade 1 spondylolisthesis require surgery?

Usually not based on the grade alone. Many Grade 1 slips are managed without surgery. Surgery is considered only in selected cases, such as persistent disabling symptoms, progressive neurologic problems, significant stenosis, or instability.

Can Grade 1 spondylolisthesis cause sciatica?

Yes, it can contribute to sciatica if it narrows the space for a nerve or irritates a nerve root. But sciatica can also come from other causes, such as a disc herniation or spinal stenosis.

What is the Meyerding classification?

The Meyerding classification grades spondylolisthesis by the percentage of slip. Grade I is 0–25%. Grade II is 25–50%. Grade III is 50–75%. Grade IV is 75–100%. Grade V is more than 100% and is called spondyloptosis.

What is the difference between spondylolisthesis and anterolisthesis?

Spondylolisthesis means one vertebra has slipped compared with the vertebra below it. Anterolisthesis means the slip is forward. Many reports use these terms similarly when describing a forward slip.

Can a Grade 1 slip get worse over time?

Some Grade 1 slips stay stable. Some progress. Risk varies by age, cause, level, disc degeneration, and whether there is abnormal motion. New or changing symptoms may change how the finding is followed.

Does the percentage of slip match the amount of pain?

No. The percentage measures alignment. It does not measure inflammation, nerve irritation, muscle spasm, instability, or disability.

Why does my MRI say Grade 1 but my pain is severe?

Severe pain can happen for many reasons. A Grade 1 slip may be involved if it matches nerve compression or other findings. But pain can also come from discs, joints, nerves, muscles, the sacroiliac joint, or other sources.

What other MRI findings matter besides the slip grade?

Important findings include foraminal narrowing, lateral recess stenosis, central canal stenosis, nerve compression, disc degeneration, facet joint arthritis, and signs that match your symptoms. Stability may also need standing or flexion-extension X-rays when motion is a concern.

References

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Spondylolisthesis. StatPearls. NCBI Bookshelf. Treasure Island, FL: StatPearls Publishing. Updated regularly. https://www.ncbi.nlm.nih.gov/books/

North American Spine Society. Diagnosis and Treatment of Degenerative Lumbar Spondylolisthesis: Evidence-Based Clinical Guidelines. 2nd ed. Burr Ridge, IL: North American Spine Society; 2014.

North American Spine Society. Diagnosis and Treatment of Adult Isthmic Spondylolisthesis: Evidence-Based Clinical Guidelines. Burr Ridge, IL: North American Spine Society; 2014.

Kalichman L, Hunter DJ. Diagnosis and conservative management of degenerative lumbar spondylolisthesis. European Spine Journal. 2008;17(3):327–335. doi:10.1007/s00586-007-0543-3

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Weinstein JN, Lurie JD, Tosteson TD, et al. Surgical compared with nonoperative treatment for lumbar degenerative spondylolisthesis: four-year results in the Spine Patient Outcomes Research Trial. Journal of Bone and Joint Surgery American Volume. 2009;91(6):1295–1304. doi:10.2106/JBJS.H.00913

Brinjikji W, Luetmer PH, Comstock B, et al. Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. AJNR American Journal of Neuroradiology. 2015;36(4):811–816. doi:10.3174/ajnr.A4173

Boden SD, Davis DO, Dina TS, Patronas NJ, Wiesel SW. Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. Journal of Bone and Joint Surgery American Volume. 1990;72(3):403–408.

American College of Radiology. ACR Appropriateness Criteria® Low Back Pain. Revised 2021. https://acsearch.acr.org/

Gardner A, Gardner E, Morley T. Cauda equina syndrome: a review of the current clinical and medico-legal position. European Spine Journal. 2011;20(5):690–697. doi:10.1007/s00586-010-1668-3

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