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Making the Diagnosis of Craniocervical Instability

Published on Oct 15, 2020

If you read this blog, you know that I often write about what I experience on a day to day basis. This week I had a telemedicine evaluation with a patient who was scheduled for a C1-C2 screw fixation surgery who didn’t meet our diagnostic criteria for a much less invasive injection-based procedure to treat craniocervical instability. She seemed perplexed that a surgeon had put her on the schedule for this invasive procedure and yet she couldn’t meet our criteria for a diagnosis of CCI. So how is that diagnosis made? Let’s review.

What is CCI?

Craniocervical Instability or CCI is excessive motion where the head meets the neck, usually due to loose or damaged ligaments. These are the ligaments that hold the head onto the upper spine. To learn more, see my video below:

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What Criteria Do We Use to Make a Diagnosis of CCI?

While I’ll focus this blog on the diagnosis of CCI, this same diagnostic process should be used for all diagnoses. We use these six main criteria:

Mechanism
History
Physical Exam
Imaging
Response to diagnostic blocks
Response to Treatment

Think of this as putting together puzzle pieces that create a picture. Your job to guess what that picture is once the pieces are correctly assembled. For example, there are times when you won’t know what the picture is for sure until all six pieces are connected. Or there are times when three pieces are placed when it’s easy to guess the picture because it can’t be anything else. So let’s review these criteria, or puzzle pieces, one by one:

Mechanism

If the patient has a diagnosis where the ligaments that hold the head on are damaged or loose, how did that happen? For example, trauma to the neck or head can cause CCI by partially tearing ligaments like the alar or transverse. Hence, did the patient hit their head forcefully or have a neck injury in a car crash? Also, the ligaments that hold the head on, like others in the body can be loose due to abnormal connective tissue formation. This would be the cause in patients with Ehlers Danlos Syndrome (EDS).

If I use the patient above, the mechanism didn’t fully fit CCI. There was no known trauma. She did have a history of spinal hypermobility, but tests for EDS didn’t pan out. So while it’s possible that she may have loose ligaments in the spine only as some sort of rare EDS variant, we’ll call this “Positive/Negative” for now. Meaning that it’s not clearly positive for CCI, but there could be something here.

History

Do the patient’s symptoms match CCI? For example headaches, dizziness/imbalance, visual problems, fast heart rate, postural hypotension, wandering pain or numbness symptoms. We need to careful here, as many of these same symptoms are also caused by other conditions. Hence, just this puzzle piece is incomplete by itself.

Our patient above did have a convincing set of CCI symptoms. So this puzzle piece is a firm positive.

Physical Exam

In this case, let’s define what an exam is and isn’t. Most patients get cursory exams that last a few minutes. That’s not what I’m talking about. In this case, I mean at least 20 minutes with the doctor (not a mid-level like a PA or NP) performing a physical exam.

In this case, the focus is on confirming things that are common in patients with upper cervical pain or injury. For example, tenderness in the upper cervical spine facet joints or issues with sensation in the upper cervical spinal nerve root territories. Or balance/proprioceptive problems that can be linked back to the upper neck.

Our patient above had only seen a surgeon knowledgeable in upper cervical surgery, so while I had limited data on what was found, we’re usually talking about the few minute exam versus the long format type. Hence, we’ll call this one positive/negative for now.

Imaging

Most patients believe that an MRI or CT Scan is like the Oracle of Delphi and that by divining the angles and other things, that’s all that’s required to nail a diagnosis of CCI. Nope. While imaging can be helpful, it’s false positive rate is way too high to be used alone. Meaning, there are people walking around out there with all sorts of crazy CCI angles and measurements that are fine and have no symptoms.

We need to use imaging in a way that considers that false-positive rate carefully and rationally. For example, based on the published literature, what are the odds that what I’m looking at is a normal variant and not associated with symptomatic CCI? For example, this data was recently published for DMX. If the patient had more than a 3 mm overhang between C1 and C2 with side bending of the neck, it was very unlikely that this would be found in a normal patient without symptoms and more likely to be associated with trauma.

In our patient above, the surgeon relied only on a C1-C2 rotational measurement on CT scan. According to the patient, that measurement was only a few degrees beyond the upper limit. Meaning that since all measurements have an error rate, if we did the measurement a few times, sometimes it would be normal and others abnormal. Hence, we have another positive/negative. Therefore I discussed with the patient that getting a DMX study would help add additional information to this puzzle piece.

What is DMX? What is this new data? See my video below:

Response to Diagnostic Blocks

This means that the areas that hurt are diagnosed by precisely injecting anesthetic into that area to see if that numbs out the pain or takes away other symptoms. Sometimes this part of the evaluation isn’t needed because the other puzzle pieces all fit. However, when there’s a question about the diagnosis, having this ability comes in handy. Here are some common diagnostic blocks we use for CCI:

C0-1 or C1-C2 facet injections. These are upper neck joints that get beat up in CCI patients and often become painful and themselves can cause headaches or balance issues. The problem? Only about a dozen providers in the US have any substantial experience with these x-ray guided procedures. There are likely a hundred providers that have some experience, and the rest of the spine interventionalists have limited experience. Hence, finding a local provider who knows how to do these can be problematic.
Occipital nerve blocks. There are several nerves that can cause headaches here including the greater occipital nerve, the lesser, and the third occipital nerve. There are also two levels of knowledge for providers, one common and one rare. What I mean by that, is that these nerves can get pinched in common places or uncommon places. This usually happens in CCI patients when the upper neck muscles go into overdrive to provide stability, irritating these nerves. The common occipital nerve blocks are easy to do and it’s not hard to find a doctor who has performed a reasonable number of those procedures. The uncommon forms are more difficult to source, as they require advanced ultrasound injection skills.
Superficial Cervical Plexus Blocks. In CCI patients, the sternocleidomastoid muscles often go into overdrive as well. Under that muscle is a structure called the superficial cervical plexus (aka transverse cervical nerve) that can also be blocked. Irritation of this nerve can cause headaches, side of face and neck pain, or ear pain.

Our patient above had only simple occipital nerve blocks, so was missing most of the injection-based diagnostic workup. So again, another positive/negative.

Response to Treatment

This final puzzle piece is whether the patient has had the correct response to treatments that often help CCI patients. For example, here are some common ones:

Upper cervical chiropractic care-here many CCI patients can get excellent short-term relief of symptoms
Neck or head bracing-This will usually dramatically reduce symptoms as the unstable neck is temporarily stabilized. On the other hand, some CCI patients can’t tolerate certain braces, so finding the right cervical collar is key.
Worsening with Active PT-While many CCI patients are helped by physical therapy that involves manipulation, most are made worse by any attempt at neck strengthening.
Injections-Diagnostic blocks can also be a treatment if they’re done with orthobiologics like platelet-rich plasma. In this case, the patient may realize temporary relief from treating beat up upper neck joints or nerves, despite not treating the instability directly. Hence, the pain usually returns.

Our patient did try a collar, but it didn’t give her dramatic relief. Hence, this category is positive/negative.

Diagnostic Certainty vs. Disability vs. Risk

Now that we have all of our diagnosis puzzle pieces, it’s time to lay these out on the table to see if they fit together and what diagnostic picture that produces. The more we have that fit the diagnosis the better.

Sometimes all of the pieces fit perfectly together and all match a diagnosis of CCI. However, in the real world, sometimes the picture is harder to see clearly. For example, some pieces may be positive for CCI and some not so much. Hence, if we have all six that match up, our diagnostic certainly is high. If we have only two that match up, our diagnostic certainty is low.

The next step is looking at disability. Is this patient highly disabled or not very disabled? If the patient is highly disabled and has low diagnostic certainty, accepting more treatment risk may be reasonable. The best for a high-risk treatment would be high diagnostic certainty for CCI and high disability. The worse would be low certainty that the patient has CCI and low disability.

Finally, the risk of treatment is critical. If the risk is very small, like a specific upper cervical chiropractic adjustment, then we can have low diagnostic certainty and low disability all day long. Here’s how CCI treatment risk lays out:

LOW RISK

Bracing
Upper Cervical Manipulation
Occipital Nerve Blocks

MODERATE RISK

Occipital nerve blocks
Superficial cervical plexus blocks
Posterior ligament prolotherapy
Upper neck facet injections

HIGHER RISK

PICL Procedure (direct injection of the ligaments that hold the head on to tighten those ligaments and reduce instability)

HIGHEST RISK

C1-C2 screw fixation
Larger upper cervical fusions with extensive hardware

So how did our patient compare here? She has a low to moderate diagnostic certainty, moderate levels of disability, and is already scheduled for a “Highest Risk” procedure. Hence, my advice to her was to get more information so that we can increase the certainty that she has CCI before undergoing an irreversible surgical procedure that is very high risk.

The upshot? As you can see, getting to an accurate diagnosis is more than just taking an image and performing a cursory exam. It’s hard work, especially with CCI. Hence, please don’t sign up for any invasive surgeries until you tick all of the boxes above!