Cervical Spondylotic Myelopathy (CSM)

Our Specialists for Cervical Spondylotic Myelopathy (CSM)

Surgery for CSM is technical and the stakes are real: the spinal cord does not tolerate mistakes, and the decision to come in from the front, from the back, or both, has to match your specific anatomy. The spine surgeons below focus on degenerative cervical myelopathy as part of their weekly practice at UChicago.

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's work on the Quality Outcomes Database has helped define what a meaningful recovery looks like after CSM surgery, including severity-adjusted minimum clinically important differences on the mJOA. He trained at Johns Hopkins, where he co-authored one of the early series on laminectomy with instrumented fusion for multilevel CSM (Neurological Research, 2009).

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's published work on the surgical management of cervical spondylotic myelopathy with laminectomy and instrumented fusion helped establish how to decompress the cord across multiple levels while preserving cervical alignment (Neurological Research, 2009). For CSM patients with multilevel posterior compression, laminectomy with fusion remains one of his routine operations.

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 spine neurosurgeons who sees cervical myelopathy patients weekly at UChicago, evaluating whether an anterior approach, posterior laminoplasty, or laminectomy with fusion best matches the compression pattern and cervical alignment on each individual MRI.

What Is Cervical Spondylotic Myelopathy?

Cervical spondylotic myelopathy — increasingly called degenerative cervical myelopathy (DCM) — is spinal cord injury caused by age-related wear and tear in the neck. Over decades, discs dry out and bulge, bone spurs form, ligaments thicken, and the space available for the spinal cord quietly shrinks. At some point the cord itself starts getting pinched, and the wiring that carries signals between your brain and the rest of your body begins to misfire.

CSM is the most common cause of spinal cord dysfunction in adults, and with aging populations worldwide its numbers are climbing. It usually shows up after age 50, but people in their 40s — and occasionally younger — can develop it too, especially if they were born with a narrow spinal canal.

What makes CSM tricky is how slowly it sneaks up. Early on, most people blame their hands on arthritis and their legs on getting older. By the time they see a neurosurgeon, the spinal cord has often been compressed for years. The good news is that once it's recognized, surgery is highly effective at stopping the progression and, for most patients, recovering function.

What Does It Feel Like?

CSM symptoms are a mix of hand problems, balance problems, and sometimes pain — but pain is often not the main thing, which is part of why CSM gets missed. The symptoms typically come on over months to years, not days.

Hand and arm symptoms

• Clumsiness — dropping things, fumbling keys or coins, struggling with buttons, zippers, or bra clasps
• Handwriting that's gotten messier
• A pins-and-needles or numb feeling in the fingers, often in both hands
• Weakness in the grip or in fine finger movements
• A sense that your hand isn't quite "yours" anymore

Leg and walking symptoms

• Gait instability — feeling unsteady, wide-based walking, tripping or near-falls
• Legs feeling stiff or heavy, like walking through mud
• Trouble with stairs or uneven ground
• A "drunk" feeling without alcohol, especially in the dark or with eyes closed

Other signs your doctor may notice

• Hyperreflexia — knee and ankle reflexes that are overly brisk
• A positive Hoffmann sign or Babinski sign (abnormal reflex responses that suggest spinal cord involvement)
• Spasticity — muscles that feel tight or jumpy
• In advanced cases, bladder urgency or loss of control

Neck pain is common but not universal. Many people with significant CSM have surprisingly little neck pain — their main complaint is "I just can't do what I used to."

How Is It Diagnosed?

Diagnosis starts with a careful history and a neurologic exam. A spine surgeon or neurologist will test your strength, sensation, reflexes, and gait, and check specifically for the signs of spinal cord compression — brisk reflexes, a Hoffmann sign, clonus, and sometimes an abnormal gait pattern.

MRI is the key test

A cervical spine MRI is what confirms the diagnosis. It shows the bones, discs, ligaments, and — most importantly — the spinal cord itself. We look for three things:

• Where the spinal cord is being compressed (which levels, from the front or the back, one side or both)
• How severe the compression is — whether there's still cerebrospinal fluid around the cord or it's been squeezed flat
• Signal change inside the cord (a bright spot on T2 images) — which means the cord has been injured, not just pushed on

Plain X-rays, including flexion and extension views, are often added to show the shape of the neck (is it still in its normal gentle curve, or has it straightened or reversed into kyphosis?) and to check for instability. A CT scan may be ordered if we need a better look at the bone or at ossification of the posterior longitudinal ligament (OPLL), a specific condition where a ligament behind the vertebrae turns to bone.

Scoring how severe it is

Spine surgeons use the modified Japanese Orthopaedic Association (mJOA) score to grade CSM severity. It rates function in four areas — upper limb motor, lower limb motor, sensation, and bladder — on an 18-point scale. By convention: 15-17 is mild, 12-14 is moderate, and less than 12 is severe. The mJOA helps guide treatment decisions and is the standard outcome measure used across almost every major CSM study.

Where Is the Compression Coming From?

CSM isn't really a single disease — it's a final common pathway for several different kinds of wear on the cervical spine. The pattern of compression drives which operation you need, so your surgeon will spend real time sorting this out on your MRI.

Anterior (front) compression

The most common source. Bulging discs and bone spurs push back into the cord from the front. Since the problem is in front, the most direct fix is usually from the front — an anterior cervical discectomy and fusion (ACDF) or, for taller compression that crosses a vertebral body, a corpectomy (removing the body of the vertebra). Anterior surgery is especially favored when only one or two levels are involved, or when the neck has lost its normal curve.

Posterior (back) compression

Thickened ligamentum flavum and infolded joint capsules squeeze the cord from behind, often across several levels at once. When compression is mostly from the back and the neck still has a reasonable curve (lordosis), a posterior operation — laminoplasty or laminectomy with fusion — lets the cord drift backward into the new space and relieves pressure indirectly.

Circumferential (all around) compression

In advanced CSM, the cord is squeezed from both the front and the back. These cases sometimes need a combined front-and-back operation in one or two stages to get the cord fully free.

Ossification of the posterior longitudinal ligament (OPLL)

A specific variant where the ligament behind the vertebral bodies slowly turns into bone and indents the cord. OPLL often involves many levels and is a particular reason surgeons may choose a posterior approach, since trying to drill out ossified ligament from the front can be risky.

How Is It Treated?

The big picture

For moderate and severe CSM (mJOA below 15), the international AO Spine clinical practice guidelines recommend surgery. The reason is simple: the natural history of moderate and severe CSM is progression. Studies show that 20-60% of patients decline on the mJOA within a few years if they're treated non-operatively, and once the cord is injured enough to cause myelopathy, it rarely gets better on its own. For mild CSM (mJOA 15-17), you and your surgeon have a real choice — either a trial of structured non-operative care with close monitoring, or surgery. Progression can happen in mild CSM too, and some patients prefer to operate before decline sets in.

Non-operative care — physical therapy, activity modification, avoiding high-impact sports — doesn't reverse cord compression, but it can help with neck pain and function in milder cases. There is no evidence that cervical traction, chiropractic manipulation, or injections treat myelopathy itself, and aggressive neck manipulation is specifically discouraged when there's cord compression.

Anterior cervical discectomy and fusion (ACDF)

Through a small incision on the front of the neck, the surgeon removes the offending disc(s) and any bone spurs pushing on the cord, then places a spacer (often with plate and screws) to restore disc height and fuse the vertebrae together. ACDF is the workhorse operation for one- or two-level disease coming from the front. It has a long track record, short hospital stays, and most patients can swallow, talk, and go home within a day or two.

Anterior cervical corpectomy

When compression spans a full vertebral body, the surgeon removes that body entirely and reconstructs it with a cage or strut graft. Corpectomy gets a wider decompression than multiple ACDFs but is a bigger operation.

Posterior laminoplasty

Through the back of the neck, the surgeon makes a hinge on one side of each lamina and opens the other side like a door, enlarging the spinal canal without removing bone or fusing any levels. Laminoplasty preserves motion and avoids the risks of hardware failure and adjacent-segment degeneration that come with fusion. It's a strong choice for multilevel posterior compression in a neck that still has a good lordotic curve.

Laminectomy with posterior fusion

The surgeon removes the laminae at the compressed levels and adds a screws-and-rods fusion to prevent the neck from collapsing into kyphosis afterward. This is a versatile operation for multilevel posterior disease, especially when the cervical alignment is already compromised, when OPLL involves several levels, or when there's pre-existing neck pain that fusion can help.

How surgeons decide

There's no single "best" operation. The AO Spine guidelines emphasize matching the approach to the patient. In broad strokes: one- or two-level disease from the front usually goes anterior; multilevel disease from the back in a lordotic neck often goes posterior (with laminoplasty favored when fusion can be avoided); kyphotic necks, ossified ligaments, and complex deformities may need combined approaches. The AOSpine North America CSM study of 264 patients found that both anterior and posterior approaches produced meaningful mJOA improvement at two years, with some differences in the magnitude of recovery depending on selection.

What Are the Outcomes?

The most important thing to know about CSM surgery is that it works. The prospective multicenter AOSpine North America and AOSpine International studies — together enrolling 757 patients with CSM across 26 sites — showed consistent, significant improvement on the mJOA, Nurick grade, NDI, and SF-36 at six months, one year, and two years after surgery, regardless of country or approach. Mild, moderate, and severe patients all benefited; severe patients had the most room to improve.

The minimum clinically important difference (MCID) on the mJOA is about 1 point for mild, 2 points for moderate, and 3 points for severe disease — so "a small number change" on a spine-surgery follow-up actually corresponds to a real-life improvement you can feel.

Complication rates

The AOSpine North America complications analysis of 302 CSM patients reported an overall perioperative complication rate of about 15-16%, with most complications being minor. Serious complications were under 5%. The most common specific complications differ by approach:

• ACDF: temporary dysphagia (difficulty swallowing) in 5-10%, hoarseness from vocal cord nerve irritation (usually temporary), rare dural tear, and late adjacent-segment degeneration
• Corpectomy: higher rates of graft or hardware problems than ACDF; small risk of airway swelling
• Laminoplasty: C5 nerve palsy (weakness of shoulder abduction) in about 5%, which typically recovers; axial neck pain
• Laminectomy with fusion: C5 palsy, wound complications, pseudarthrosis (failure to fuse), and the usual risks of posterior hardware

The bottom line

Across thousands of patients followed prospectively, CSM surgery reliably halts neurologic decline and produces meaningful functional recovery in the large majority of patients. Better preoperative function, shorter duration of symptoms, younger age, and non-smoker status all predict better results — which is a concrete reason not to wait if your surgeon is recommending an operation.

References