Degenerative Spondylolisthesis

Our Specialists for Degenerative Spondylolisthesis

Degenerative spondylolisthesis is one of the most studied conditions in spine surgery, and the decision of whether to decompress alone or to add a fusion is still one of the most debated. The surgeons who treat this condition well are the ones who know the literature, tailor the operation to the individual patient, and have done enough of these cases to make the right call.

Mohamad Bydon, M.D.

Chair, Department of Neurological Surgery

Dr. Bydon is the Chair of Neurological Surgery at UChicago and a pioneer in minimally invasive and robotic spine surgery. He led the stem cell trial, the first-in-human stem cell therapy for spinal cord injury, and holds 12 medical device patents with over 600 peer-reviewed publications. He was recruited to UChicago from Mayo Clinic. Dr. Bydon launched one of the nation's first dedicated robotic and minimally invasive spine programs in 2015, has published extensively on fusion outcomes for Grade I degenerative spondylolisthesis using the Quality Outcomes Database, and co-authored landmark comparisons of minimally invasive versus open TLIF for this exact condition (Neurosurgical Focus, 2017).

Timothy F. Witham, M.D., FACS

Section Chief, Spine Surgery

Dr. Witham is Section Chief of Spine Surgery at UChicago and a pioneer in augmented reality-guided spine surgery. In 2020 he performed the first FDA-cleared AR-guided spine surgery on a living patient using the xvision system, and he has published extensively on AR-assisted pedicle screw placement. He came to UChicago from Johns Hopkins, where he was Professor of Neurological Surgery and Orthopaedic Surgery and served as co-program director of the neurosurgery residency. Dr. Witham performed the first FDA-cleared augmented reality-guided spine surgery on a living patient and has published on AR-assisted pedicle screw placement accuracy approaching 98% (J Neurosurg Spine, 2021) — directly relevant to the screw placement precision that makes modern MIS fusion safe.

Martin Herman, M.D., Ph.D.

Program Director, Neurological Surgery Residency

Dr. Herman is Program Director of the Neurological Surgery Residency and a complex spine surgeon who practices the full spectrum of spine and neurorestoration procedures. He co-developed a fully implantable wireless intraspinal microstimulation device for restoring motor function after spinal cord injury, with publications in Artificial Organs and Scientific Reports. He has been named a Top Chicago Doctor for over a decade. Dr. Herman is one of the complex spine surgeons who evaluates degenerative spondylolisthesis patients weekly at UChicago and performs the full range of decompression-only and fusion procedures, including minimally invasive approaches.

What Is Degenerative Spondylolisthesis?

Your spine is made of a stack of bones called vertebrae, held in careful alignment by discs, ligaments, and small joints on the back of each bone called facet joints. As you age, the discs dry out and the facet joints wear down — and sometimes, the joint wears out so much that one vertebra starts to slide forward on the one below it. That slip is called a spondylolisthesis.

The most common level for this to happen is L4 on L5, right at the base of the lower back. Women after menopause are affected about four times more often than men, and the condition becomes increasingly common after age 50.

When a vertebra slips forward, it drags the spinal canal and the nerve roots with it, pinching them. That pinching — called spinal stenosis — is what causes most of the symptoms. So when we talk about treating spondylolisthesis, we're really treating two problems at once: the nerve compression, and the instability from the slip itself.

What Does It Feel Like?

The hallmark of degenerative spondylolisthesis is a combination of back pain and leg symptoms that get worse with standing and walking, and better when you sit down or bend forward (which opens the spinal canal and briefly takes pressure off the nerves).

Common symptoms

• Lower back pain that's worse with standing or extending backward
• Leg pain, numbness, or tingling that runs into the buttock, thigh, or calf — usually on both sides
• Neurogenic claudication — the need to stop and sit or lean on a shopping cart after walking a block or two, because your legs feel heavy, tired, or numb
• Relief when sitting or bending forward — many patients say they can walk fine in a grocery store because they're leaning on the cart
• Weakness in the legs or feet if the nerve compression has been going on long enough

Red-flag symptoms that should get you to a spine specialist urgently include new weakness, foot drop, loss of bladder or bowel control, or numbness in the area that would touch a saddle.

How Is It Diagnosed?

Diagnosis starts with a careful conversation and physical exam. Your surgeon will want to know how far you can walk before the symptoms start, what makes them better, and whether you have any weakness. Then we move to imaging.

Standing X-rays

Here's something important: an MRI lying flat can miss or under-estimate the slip. The slip often only shows up when you're standing up, because gravity is what pulls the vertebra forward. That's why we routinely order standing flexion-extension X-rays — you bend forward and backward, and we measure how much the slip moves. A slip that changes more than 3 mm between positions is considered unstable, and that affects treatment decisions.

MRI

An MRI shows the soft tissues — the discs, the ligaments, and most importantly the spinal canal and nerve roots. It tells us where the stenosis is, which nerves are being pinched, and how severe the compression is.

CT scan

A CT scan shows bone detail better than an MRI. It's especially useful for surgical planning when fusion and screw placement are being considered.

Types of Spondylolisthesis

Spondylolisthesis is sorted in two ways: by cause and by severity.

By cause

• Degenerative — by far the most common type in adults. The facet joints and discs wear down over years, and the vertebra slips forward. This is what this article is mostly about.
• Isthmic — caused by a stress fracture in a small piece of bone at the back of the vertebra (the pars interarticularis). This usually happens in adolescence and may not cause symptoms for decades. Most common at L5-S1.
• Traumatic — caused by a high-energy injury that fractures the spine
• Pathologic — caused by a tumor or infection weakening the bone
• Congenital — present from birth due to how the spine formed

By severity: the Meyerding grade

The Meyerding classification, developed in 1932 and still used today, describes how far the vertebra has slipped as a percentage of the width of the vertebra below it:

• Grade I — up to 25% slip (most degenerative cases)
• Grade II — 25-50% slip
• Grade III — 50-75% slip
• Grade IV — 75-100% slip
• Grade V (spondyloptosis) — the vertebra has slipped completely off the one below it

Most degenerative cases are Grade I or II. High-grade slips (III-V) are almost always isthmic or congenital and often need more complex reconstructive surgery.

How Is It Treated?

Start with the conservative stuff

Most people with degenerative spondylolisthesis never need surgery. The first line of treatment is physical therapy focused on core stabilization, hip flexibility, and posture. Weight loss helps when it's relevant. NSAIDs and short courses of other pain medications can take the edge off a flare. For leg pain that isn't settling, epidural steroid injections can provide weeks to months of relief and help you get through physical therapy.

If you've tried a reasonable course of non-operative care for at least 8-12 weeks and you're still limited — you can't walk the distances you want, your leg pain is keeping you from sleeping, or you're developing weakness — that's when surgery enters the conversation.

Decompression alone

The simplest operation is a laminectomy — removing the small piece of bone at the back of the spine that's pressing on the nerves. The nerves are unroofed, the stenosis is relieved, and you leave the slip alone. The advantages are a shorter operation, less blood loss, a faster recovery, and no hardware. The disadvantage is the risk that, over time, the slip progresses and you need another operation.

Decompression with fusion

The alternative is to decompress the nerves and stabilize the unstable segment with a fusion — placing screws and rods between the two vertebrae so they heal together into one solid piece, usually with a small cage placed into the disc space for support. The fusion stops the slip from getting worse and addresses the instability directly. The trade-off is a longer operation, more blood loss, a longer recovery, and the risks that come with hardware.

The big debate: to fuse or not to fuse?

Two landmark randomized trials published back-to-back in the New England Journal of Medicine in 2016 came to different conclusions on this question. The American SLIP trial (Ghogawala et al.) found that adding fusion to laminectomy produced better quality-of-life scores and substantially fewer reoperations at 4 years. The Swedish trial (Försth et al.) found no difference between fusion and decompression alone at 2 and 5 years. A Scandinavian trial published in 2021 (NORDSTEN-DS, Austevoll et al.) similarly found decompression alone non-inferior at 2 years, though with a somewhat higher reoperation rate.

The honest answer is that the right operation depends on the individual: how much instability is on the standing films, whether the patient has mostly leg pain or mostly back pain, their bone quality, their age, and their goals. An experienced spine surgeon will walk you through all of this and pick the operation that fits you.

Minimally invasive and robotic approaches

When fusion is the right choice, there are several ways to do it. A minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) places the interbody cage and pedicle screws through small tubular retractors, splitting the back muscles rather than cutting them. Published 5-year outcomes from the Quality Outcomes Database registry show MIS-TLIF and open TLIF deliver equivalent long-term results for Grade I spondylolisthesis, with less blood loss and shorter hospital stays on the MIS side.

Robotic navigation is the next layer. A robotic arm, guided by a pre-operative plan built on your CT scan, helps the surgeon place the pedicle screws with millimeter accuracy. This is especially useful in minimally invasive cases, where the surgeon can't see as much of the anatomy directly. UChicago offers robotic and augmented-reality guided spine fusion in dedicated operating rooms.

What Are the Outcomes?

Outcomes for degenerative spondylolisthesis surgery are, broadly speaking, very good. Most patients who meet surgical criteria experience meaningful improvement in leg pain, walking distance, and overall function.

The long-term SPORT data — an 8-year follow-up of one of the largest spondylolisthesis trials ever done — showed that surgically treated patients maintained substantial improvements in pain, function, and disability compared with non-operatively treated patients. The SLIP trial's 4-year results showed that adding fusion to laminectomy produced durable improvement in physical quality of life and, importantly, cut the reoperation rate roughly in half (14% with fusion vs. 34% decompression-alone at 4 years).

The upshot is that both operations work — and the best results come from a surgeon who chooses the right one for the right patient, performs it well, and manages the recovery carefully. That's where experience actually changes outcomes.

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