Medically reviewed by Scott A. Meyer, MD, FAANS · Last reviewed: Sept 6, 2026

If you have been told you have lumbar spinal stenosis with a slipped vertebra, and that surgery may help, you have probably heard about two options. The first is spinal fusion, which has been the standard operation for this problem for decades. The second is the TOPS System, a newer spinal implant designed to stabilize the spine without fusing it.

Both operations begin the same way: the surgeon relieves the pressure on your nerves. The difference is what happens next. Fusion permanently joins two vertebrae so they no longer move against each other. The TOPS System replaces the small joints at the back of the spine with a device that allows controlled movement.

Neither is right for everyone. This article explains how each surgery works, what the research shows so far (including its limits), and the questions that usually decide which one a spine surgeon recommends.

The problem both surgeries treat

The lumbar spine (lower back) has five vertebrae. At the back of each level sit two small facet joints, which guide movement, and a band of ligament behind the spinal canal. With age, the joints can enlarge, the ligament can thicken and the disc can bulge. Together, these changes narrow the space around the nerves. That narrowing is called spinal stenosis.

Sometimes the worn facet joints also let one vertebra slide forward over the one below it. This is degenerative spondylolisthesis. Doctors grade the slip by how far the vertebra has moved. Grade I, the mildest, means it has slipped less than a quarter of the width of the bone below.

The classic symptom is not back pain alone. Many people notice aching, heaviness, numbness or tingling in the buttocks and legs that builds when they stand or walk and eases when they sit or lean forward. Some find they can walk farther leaning on a shopping cart. Pain that travels down one leg can resemble sciatica from a herniated disc, and poor circulation in the legs can cause similar walking pain. Part of an evaluation is telling these causes apart.

Most people start with nonsurgical care such as physical therapy, activity changes, medication and, in some cases, injections. Patients in the TOPS trial had tried at least six months of nonsurgical treatment before enrolling.^[4] Surgery usually becomes a conversation when symptoms keep limiting daily life despite that care, or when there are signs of nerve damage.

Symptoms that need prompt medical attention: new weakness in a leg or foot, numbness in the groin or inner thighs, or new trouble controlling your bladder or bowels. These are uncommon but can signal severe nerve compression.

What each surgery actually does

Step one is the same: decompression

In both operations, the surgeon removes bone and thickened ligament to open the spinal canal. This is often called a laminectomy. When a vertebra has already slipped, removing these structures can leave the segment less stable, which is why surgeons often add a second step.

Whether that second step is always needed is still debated. Two major randomized trials published in 2016 compared decompression alone with decompression plus fusion and reached different conclusions.^[6][7] This is one reason individual evaluation matters so much.

Spinal fusion

In a fusion, the surgeon places screws in the vertebrae above and below, connects them with rods and usually inserts a spacer (cage) with bone graft where the disc was. The most common version for this condition is a transforaminal lumbar interbody fusion, or TLIF. Over the following months, the bone grows across the level so the two vertebrae heal into one solid segment.

Fusion is well studied and reliable. The trade-off is that the fused level no longer moves, and some of that motion and stress shifts to the levels above and below. Over time, those neighboring levels can wear out, a problem called adjacent segment degeneration. Maxim Spine’s surgeons perform several fusion techniques, including minimally invasive approaches, described on our lumbar spine procedures page.

The TOPS System (spine)

TOPS stands for Total Posterior Spine. After decompression, the surgeon removes the facet joints and attaches the implant to the vertebrae with four screws. The device has a flexible core that lets the level bend and rotate within a controlled range. It is designed to stabilize the segment without requiring the bones to fuse.^[1] This is called posterior arthroplasty, or facet replacement. It is different from a lumbar disc replacement, which replaces the disc at the front of the spine.

You can read more about how the implant works on our TOPS System page.

TOPS System vs. spinal fusion: side by side

What the research shows so far

The TOPS System was studied in a randomized FDA trial that enrolled 321 patients at 37 U.S. centers. Patients were assigned to TOPS or fusion in a 2-to-1 ratio.^[4] Researchers judged each patient against a “composite clinical success” measure. A patient counted as a success only if they met every criterion: no reoperation, no major device problem, a meaningful improvement in disability scores and no new or worsening nerve deficit.

• Two years (first report, 2023): 85% of TOPS patients met the composite success measure, compared with 64% of fusion patients.^[2]
• Two years (larger report, 2024): 73.5% vs. 25.5% using the study’s predetermined composite score. The fusion group also had a higher rate of symptomatic adjacent segment degeneration.^[3]
• Three years (2026): 76.0% of TOPS patients vs. 56.8% of fusion patients.^[4]

The FDA approved the TOPS System in June 2023 as an alternative to fusion for certain patients with this condition, based on the two-year results.^[8]

How to read these numbers

The percentages differ between reports because each analysis used a different group of patients and, in some cases, a different definition of success. Each report so far has also analyzed a portion of the enrolled patients rather than the full group, and some insurers’ medical policies have noted that final results were still pending.^[9] The trial is following patients for five years, with completion expected in 2027.^[10]

In plain terms: results so far favor TOPS for the specific patients it is approved for, and the trend has held from two to three years. Fusion, however, has a much longer track record. A small group of patients treated with an earlier version of the device in Israel has been followed for about 11 years with lasting improvement,^[11] but large-scale data beyond the U.S. trial’s five-year follow-up are not available yet.

“When patients ask how long the TOPS System lasts, I give them the honest answer. We have randomized data out to three years, and the results have held up. We don’t have twenty-year data yet, and fusion does. For the right patient, I think the early evidence makes TOPS a very reasonable option. I just want people making that choice with clear eyes.”

— Scott A. Meyer, MD, FAANS, Neurosurgeon, Maxim Spine

Who may be a candidate for the TOPS System

The FDA-approved indication describes a fairly specific patient:^[1]

• Age 35 to 80
• Symptomatic degenerative spondylolisthesis, grade I
• Moderate to severe lumbar spinal stenosis
• Thickened ligament and/or scarred facet joint capsule
• At a single level from L3 to L5

Beyond the label, surgeons weigh other factors. The TOPS System leaves the disc in place, so the disc itself needs to be reasonably healthy; a badly worn or collapsed disc usually points toward fusion, which removes it. Because the implant relies on screws holding in bone, bone quality matters, and osteoporosis may rule it out. A surgeon at Northwell Health, a New York academic health system, lists healthy bone and the absence of other significant problems at that level, such as a herniated disc, among the requirements.^[5] A previous fusion at the level, a slip beyond grade I, stenosis at more than one level or significant scoliosis generally point toward other options.

“The most common reason is that the problem is bigger than the device was designed for: more than one level involved, or a slip beyond grade I. TOPS was tested for a specific situation, and I don’t stretch it beyond that. The second is bone quality. The implant is anchored with screws, so if a bone density scan shows significant osteoporosis, we either address that first or choose a different approach.”

— Scott A. Meyer, MD, FAANS, Neurosurgeon, Maxim Spine

When fusion is still the better choice

Fusion is not an outdated operation. For many people it is the right one. As the Northwell surgeon puts it, fusion remains necessary for patients with spinal deformity, instability and patterns of stenosis or scoliosis that motion-preserving devices are not designed to treat.^[5] Fusion also treats many conditions outside the TOPS System’s approved use.

“Before TOPS is even on the table, I look at three things: the MRI, standing X-rays that show how much the segment moves when you bend, and what the patient wants to get back to. If the anatomy fits and the bone is healthy, I lay out both options side by side. Some patients who qualify for TOPS still choose fusion, and that’s a legitimate choice.”

— Scott A. Meyer, MD, FAANS, Neurosurgeon, Maxim Spine

A good surgical consultation should leave you understanding why one option fits your spine better than the other. The answer should never simply be that one is newer.

What recovery can look like

Both procedures are performed through an incision in the lower back under general anesthesia and usually involve a hospital stay. Most patients are encouraged to get up and walk soon after surgery, then gradually increase activity, often with physical therapy.

One practical difference is bone healing. After fusion, the vertebrae take months to knit together, and activity is often restricted during that time to protect the fusion. The TOPS System does not depend on the bone fusing. Your surgeon will still set limits while the tissues heal and the screws settle into the bone. Recovery varies with age, fitness, job demands and the extent of surgery.

“Most patients are up and walking the day after either operation. The difference shows up over the following months. After a fusion, I ask patients to protect the spine while the bone heals, so we’re more careful with bending and lifting. With TOPS there’s no fusion to protect, so the restrictions are mainly about letting the muscles and soft tissues recover.”

— Scott A. Meyer, MD, FAANS, Neurosurgeon, Maxim Spine

Questions to ask your spine surgeon

• Is my slip grade I, and at which level is it?
• Is my stenosis at one level or several?
• Would decompression alone be reasonable for me?
• Am I within the TOPS System’s FDA-approved criteria? If not, why not?
• What does my bone density look like, and should it be tested?
• How many TOPS and fusion procedures do you perform?
• What would a revision or second surgery involve with each option?
• Will my insurance cover the procedure you recommend?

Getting evaluated in New Jersey

Maxim Spine is a neurosurgical spine practice, and our surgeons perform both spinal fusion and the TOPS System. You can be evaluated at any of our four New Jersey offices:

• Morristown: 310 Madison Avenue, Suite 300, Morristown, NJ 07960
• Cedar Knolls: 197 Ridgedale Avenue, Suite 225, Cedar Knolls, NJ 07927
• Bridgewater: 745 US-202, Suite 205, Bridgewater, NJ 08807
• Verona: 799 Bloomfield Avenue, Suite 112, Verona, NJ 07044

Offices are open Monday through Friday, 9 a.m. to 5 p.m. See directions and contact details for each location. When surgery is recommended, our surgeons operate at Hackensack Meridian Morristown Medical Center, Overlook Medical Center, Cooperman Barnabas Medical Center, Hudson Regional Hospital and Mountainside Medical Center.

To make a first visit as useful as possible, bring your MRI and X-ray reports and images, including any flexion-extension (bending) X-rays. Also bring a list of the treatments you have already tried. You can meet our surgeons before your visit.

Frequently asked questions

Is the TOPS System FDA-approved?

Yes. The FDA approved it in June 2023 for adults aged 35 to 80 with grade I degenerative spondylolisthesis and moderate-to-severe stenosis at one level from L3 to L5.^[1][8]

Is the TOPS System better than fusion?

For patients who fit its approved use, the randomized trial found higher composite success rates with TOPS at two and three years.^[2][4] That does not make it better for everyone, and long-term results beyond the trial’s follow-up are not yet known.

Will insurance cover the TOPS System?

Coverage varies by insurer and plan. Some insurers’ medical policies still classify facet arthroplasty, the category the TOPS System falls into, as investigational, which can lead to a coverage denial.^[9] Your surgeon’s office can check your specific plan and request prior authorization before surgery.

Can I have the TOPS System if I’ve had back surgery before?

It depends on what was done. A previous fusion at the same level generally rules it out, because that level no longer moves. An earlier surgery without implants may not. Your surgeon will need your operative reports to tell.

How long does the TOPS implant last?

Nobody can say for certain yet. The U.S. trial is following patients for five years.^[10] Longer-term performance will become clearer as those results are published.

Is the TOPS System the same as a disc replacement?

No. The TOPS System replaces the facet joints at the back of the spine. A lumbar disc replacement replaces the disc at the front and is used for a different set of problems.

Next steps

If leg pain, numbness or heaviness is limiting how far you can walk or stand, and nonsurgical care hasn’t helped enough, an evaluation with a spine surgeon can clarify what is causing it and which options fit your situation. That may include decompression alone, fusion or the TOPS System. Request an appointment at any of our four New Jersey offices.

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Medically reviewed by: Scott A. Meyer, MD, FAANS
Specialty: Spine surgery · Board certified in neurological surgery
About the reviewer: Dr. Meyer is a board-certified neurosurgeon and the founder of Maxim Spine. After graduating from Brown University Medical School, he completed his residency at Mount Sinai Medical Center in New York City and a spine fellowship at the University of California, San Francisco. He has served as Scientific Program Chair and Annual Meeting Chair for the Spine Summit, the annual spine meeting of the American Association of Neurological Surgeons and Congress of Neurological Surgeons, and participated in an FDA trial of a motion-preservation device for lumbar spondylolisthesis. View Dr. Meyer’s full profile.

This article is for general education and is not a substitute for medical advice. Symptoms such as leg pain and numbness can have many causes, and only a qualified clinician who has examined you and reviewed your imaging can recommend a treatment.

References

1. U.S. Food and Drug Administration. TOPS System – P220002 (approval, indications for use). 2023. https://www.fda.gov/medical-devices/recently-approved-devices/tops-system-p220002
2. Coric D, Nassr A, Kim PK, et al. Prospective, randomized controlled multicenter study of posterior lumbar facet arthroplasty for the treatment of spondylolisthesis. J Neurosurg Spine. 2023;38(1):115–125. doi:10.3171/2022.7.SPINE22536. https://pubmed.ncbi.nlm.nih.gov/36152329/
3. Decompression plus lumbar facet arthroplasty versus decompression plus fusion for lumbar spinal stenosis and grade I degenerative spondylolisthesis: a prospective randomized controlled trial. J Bone Joint Surg Am. 2024;106(12):1041–1053. PMID 38713762. https://pmc.ncbi.nlm.nih.gov/articles/PMC11593996
4. Posterior lumbar facet arthroplasty versus fusion for the treatment of spondylolisthesis: 3-year results from the Total Posterior Spine System investigational device exemption study. Neurosurg Focus. 2026;61(1):E12. PMID 42385242. https://pubmed.ncbi.nlm.nih.gov/42385242/
5. Northwell Health. TOPS procedure: a fix for back pain. December 2024. https://www.northwell.edu/news/the-latest/tops-procedure-fix-for-back-pain
6. Försth P, Ólafsson G, Carlsson T, et al. A randomized, controlled trial of fusion surgery for lumbar spinal stenosis. N Engl J Med. 2016;374(15):1413–1423.
7. Ghogawala Z, Dziura J, Butler WE, et al. Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med. 2016;374(15):1424–1434.
8. U.S. Food and Drug Administration. FDA Roundup: June 16, 2023. https://www.fda.gov/news-events/press-announcements/fda-roundup-june-16-2023
9. Blue Cross and Blue Shield of Texas. Medical Policy SUR712.034: Facet Arthroplasty. 2024. https://medicalpolicy.bcbstx.com/content/dam/bcbs/medicalpolicy/pdf/surgery/SUR712.034_2024-12-15.pdf
10. Cleveland Clinic Consult QD. For spondylolisthesis, posterior lumbar facet arthroplasty promises a mobility-maintaining alternative to fusion. 2023. https://consultqd.clevelandclinic.org/for-spondylolisthesis-posterior-lumbar-facet-arthroplasty-promises-a-mobility-maintaining-alternative-to-fusion
11. Smorgick Y, Mirovsky Y, Floman Y, et al. Long-term results for total lumbar facet joint replacement in the management of lumbar degenerative spondylolisthesis. J Neurosurg Spine. 2020;32(1):36–41. doi:10.3171/2019.7.SPINE19150. https://doi.org/10.3171/2019.7.SPINE19150