Advanced Practice Provider insights into imaging review

My specific area of interest in evaluating the mild^® patient candidate is the small black area, which is the ligamentum flavum, highlighted in the image here.

In the small white area, we can see the central canal where the nerves are housed. In this image, we can see that the canal is very small, with very little white showing. This is consistent with central canal stenosis, and in this case, we can see clearly that the hypertrophic ligamentum flavum is compressing the nerves.

By moving our image up to L2-L3, we can see an excellent comparison of the healthy central canal. The large white area shows that at this level, the thin black ligament is not compressing the nerves.

In the sagittal view, it's possible to see clearly where the spinal canal narrows, and this is helpful in identifying all levels where the central canal is stenosed.

We can also see here that the patient has a disc bulge, indicative of multi-factorial central canal stenosis.

It’s important to remember that comorbidities are common among LSS patients—in fact, a Level-1 clinical study of mild^® patients demonstrated that just 5% of patients presented with central canal stenosis only. The presence of comorbidities, such as foraminal narrowing, lateral recess narrowing, or facet hypertrophy DO NOT RULE OUT patients as mild^® procedure candidates. Indeed, the same clinical study found that the majority of patients with comorbidities achieved an ODI improvement of ≥10 points at 2-year follow-up.²

Here, the measurement clearly shows an HLF of 6.38 mm. I will then repeat this measurement process at each of the levels that are affected by central stenosis (per the report, and as seen in the sagittal view).

As a reminder, any patients with HLF ≥2.5 mm may be considered a candidate for the mild^® procedure.^4,5

Imaging Review
Using the length tool in the software, I can draw a line across the ligament (the dark area indicated in the image below) to obtain the ligament measurement.

1. Request an HLF measurement in the report. If I see a patient that is suffering from “Shopping Cart Syndrome” and exhibiting symptoms consistent with lumbar stenosis with neurogenic claudication, I’ll put the primary diagnosis code as “lumbar stenosis with neurogenic claudication” on the MRI request. I’ll also add a note to the order for the radiologist to measure the ligamentum flavum at the levels that are being affected and are stenotic. This can also be programmed into an EMR system as an automated note for every lumbar MRI request. 
2. Scroll to find the best view. When the MRI is capturing images, it’s going to be at different depths, and may vary depending on the position of the patient. After I select the level of interest, I’ll typically scroll through several images (using the up and down arrow keys on my keyboard) to make sure I have the clearest view of the ligament and central canal. 
3. Find the level by starting at the sacrum. It’s possible to determine which level I’m looking at by counting from the sacrum. I also keep in mind that L5-S1 is where the spine really starts to have curvature.
4. Focus on restoring functionality. If HLF is present in the MRI, we can feel confident about a decision to move to mild^®, to provide LSS patients long-term relief* using a therapy that has a safety profile similar to an ESI, but with lasting results.² It’s common that you’ll see comorbidities that may need to be addressed eventually, but we’ll often begin with the mild^® procedure to restore functionality and help patients get back on their feet. 

*88% of mild patients avoided back surgery for at least 5 years while experiencing significant symptom relief.³

An ideal mild^® procedure candidate

Watch the video for a full description.

In this video, we present an end-to-end example of the imaging review for an ideal mild^® case. In under 5 minutes, I can:

• Review the report: Start going line-by-line. At L4-L5, the patient appears to have bulking of the ligamentum flavum, resulting in narrowing of the central canal with no other noted comorbidities. 
• Link sagittal and axial images: After selecting a 2-image layout, select the T2 images, where cerebral spinal fluid brightens up, making it easier to identify the spinal canal. 
• Evaluate the level of central canal stenosis: Even though the radiologist has provided a report, I like to review the nuances of the images, knowing that I’m looking specifically to determine whether the patient is a good candidate for mild^®. 
• Measure the ligamentum flavum: With my length tool, I can measure the ligament to make sure the HLF is ≥2.5 mm. In this case, an HLF of 4.18 mm confirms the patient is a candidate for mild^®. 

What if MRI isn’t an option? 
When a patient can’t have an MRI, we will instead send them in for a computed tomography (CT), ideally with a myelogram. A myelogram will highlight these relevant anatomical structures, so the ligament can be seen and determine the patient’s candidacy. Even if a myelogram is not an option, I try to indicate a primary diagnosis for lumbar stenosis when I order the CT, and the radiologist will then assess that patient for lumbar stenosis and HLF.

Using imaging to support patient education
When patients are in the office, I’ll often bring my laptop into the exam room and show them their imaging on screen. Being able to see their own anatomy, and specifically the hypertrophic ligament pressing on the nerves, is incredibly helpful to demonstrate this root cause of their LSS.

Then, I can also use the imaging to clearly point out how mild^® addresses a major root cause of LSS by removing excess ligament tissue and leaving no implants behind. I’ll also show them where the nerves are being compressed and educate them about how mild^® restores space in the spinal canal, which reduces the compression of the nerves. Most patients understand how the mild^® procedure works much more easily when they can see the images themselves, and it also helps them realize how the mild^® procedure can provide long-term relief and restore mobility.

How I Embrace Imagining: Don’t be intimidated—practice makes perfect!
When I first started with imaging review, I was much less comfortable and confident than I am today. Knowing that our practice is committed to helping more patients move to mild^®, I recognized that becoming comfortable with imaging review was a critical aspect of my role. Even though MRI review was not something included in my initial APP education, I realized that becoming proficient gave me an opportunity to bring additional value to our patients and practice.

The best way I found to get comfortable with imaging review was to dive in and review previous cases so I could become familiar with the anatomy and structures. Beyond hands-on experience, there are resources that offer additional support, including:

• Online video resources: I found there are many videos available online that walk through MRI reviews and bring familiarity with some of the structures. 
• Clinicians: I’d often review an MRI, and then share my findings with the physician I work with to confirm that they were seeing the same diagnosis that I saw. 
• Webinars: I'd view webinars geared towards APP education, especially in imaging, such as the “mild^® Procedure Advanced Practice Provider (APP) Didactic” here. 
• Stryker representative: Our Stryker representative has been a great resource for our practice! Stryker representative can be useful in scheduling a lunch-and-learn or meeting to review the latest educational materials for mild. 

Comfortability reviewing imaging came with additional practice and experience. Over time I noticed how many of my patients with LSS have HLF and were candidates for the mild^® procedure. By putting more patients on the path to lasting relief with mild^®, I got to see first-hand how regaining mobility can be a life-changing improvement for the patients in my care.

About James Lynch, PA

James Lynch is an Advanced Practice Provider who works as a Physician Assistant (PA) at Pain Consultants of San Diego, a leading pain management practice in Southern California. At the time of publishing, James Lynch was a paid APP Consultant for Vertos Medical, now a part of Stryker.

The opinions of James Lynch, PA stated throughout are those of the James Lynch, PA and may not necessarily be those of Stryker.