Tag Archives: Cervical spine

Best of AAST #2: Cervical Spine Clearance And Distracting Injuries

Debate has forever swirled around how to clear the cervical spine. Clear clinically? CT scan plus exam? CT only? Flexion/extension views? Distracting injury?

This last one has been problematic for a long time. What is a distracting injury? Is there a difference between lower extremity wounds vs upper chest/shoulder wounds from a distraction standpoint? Is it possible to clinically clear the cervical spine if one of these injuries exist?

Finally, a multi-institutional trial was performed that strives to answer this question. Seven Level I US trauma centers participated in this 3.5 year long study. All patients with GCS > 14 underwent a standard clinical exam regardless of whether a possible distracting injury was present. Then all underwent CT evaluation of the entire cervical spine.

Here are the factoids:

  • Distracting injuries were classified into three regions: head, torso, and extremities, but no further analysis was presented in the abstract
  • Nearly 3,000 patients were enrolled and 70% had a potential distracting injury
  • A total of 233 patients (8%) had a cervical spine injury identified by CT
  • 136 patients had a cervical injury AND distracting injury, and 14 were missed by clinical exam (10%)
  • 87 patients had a cervical injury BUT NO distracting injury, and 10 were missed by clinical exam (13%)
  • Only one injury missed by clinical exam required operation

Bottom line: This study shows the usual prevalence of cervical spine injury after blunt trauma, but adds some interesting information regarding distracting injury. Basically, clinical examination will miss about 1% of patients with a negative exam, regardless of distracting injury status. Therefore, the study suggests that clinical clearance should be attempted on all patients first, regardless of “distracting injury.”

Reference: Clearing the cervical spine for patients with distracting injuries: an AAST multi-institutional trial. Session I Paper 3, AAST 2018.

Are You Still Using MRI To Clear The Cervical Spine?

There is a fairly robust  amount of data that shows that, properly performed, the cervical spine can be cleared using a high quality CT read by a highly skilled radiologist. This is true even for obtunded patients. Pooled data suggest that the miss rate in this group is only 0.017%. And MRI is not perfect either, missing significant ligamentous injury in a small number of patients.

But it seems that some trauma professionals are still using MRI in some cases despite this data. The latest study on MRI focuses on the cost-effectiveness of the technique. The authors selected patients with GCS < 13 to be their obtunded group, which is probably a bit high. Nevertheless, they used a fairly sophisticated (meaning hard to understand) modeling-based decision analysis using a computerized simulation. This allowed them to compare different clearance strategies without performing large randomized clinical trials.

The authors considered MRI vs no MRI, false results, collar use and complications, MRI use with cost and complications, and the worst-case scenario of tetraplegia. Here is a flow chart of the scenarios considered. (Courtesy JAMA Surgery)

Here are the factoids:

  • The mean cost for followup vs no followup was $14K vs $1K, with no increase in quality adjusted life years (QALY)
  • No followup was the better strategy when the negative predictive value of CT was high (>98%), when the risk of an unstable injury treated with a collar turning into a permanent deficit was >25%, or if the chance of a missed injury becoming a permanent deficit was >58%
  • No followup MRI was the better strategy in all 10,000 iterations of the simulation

Bottom line: Yes, this is a fairly heavy computer simulation. But the reality is that we will never be able to design a large enough study to critically evaluate this issue and have it pass any IRB review. So it’s probably as good as it will ever get. It’s time to stop wasting money and putting obtunded patients in harm’s way by locking them into a relatively inaccessible MRI scanner for 30 minutes just to confirm the CT. Or keeping a collar until until the skin breaks down.

Here is a copy of the practice guideline we use for clearing all cervical spines, obtunded or not. Yes, there is some weirdness with soft collars, which mainly serve as a reminder to re-examine the patient at some point. But note the scan technique and requirement that it be read by a neuroradiologist for final clearance.

Related link:

Reference: Cost-effectiveness of Magnetic Resonance Imaging in Cervical
Clearance of Obtunded Blunt Trauma After a Normal
Computed Tomographic Finding

EAST 2018 #11: Prehospital Cervical Spine Clearance

More and more often, I am receiving trauma activation patients after blunt trauma with no cervical collar in place. Up until a year ago or so, literally everyone with even a hint of blunt trauma had one in place. Now, it is becoming a rarity. It seems that there has been a shift in the philosophy and practice of prehospital providers and the guidelines they follow. 

The group at SUNY Stony Brook reviewed their experience with prehospital spine clearance (meaning non-placement of a collar by EMS) over a 6 year period. They analyzed trends in prehospital spine immobilization during this period.

Here are the factoids:

  • Over 5,000 patients were analyzed, and the incidence of cervical spine injury remained constant at 9% over the study period
  • Placement of prehospital cervical immobilization decreased from 54% to 35%
  • The incidence of spine injury in patients without immobilization  increased from 4% to 6%
  • Of those without immobilization, 15% had a major spine injury (AIS > 3), and 19% had multisystem injuries
  • Factors significantly associated with “inappropriate” prehospital clearance included fall mechanism, elderly, functional dependence, dementia, and presence of comorbidities

Bottom line: This study is intriguing, but I worry that the study population is a bit too small to draw the best conclusions. I say this because the incidence of cervical injury is significantly higher in this study that in a larger one with 34,000 patients. This may indicate either a small sample size or some type of sample bias. I’m unclear about what data the prehospital agencies used to relax the immobilization criteria, and whether or not the criteria are being applied appropriately. It does appear, however, that the elderly are at higher risk for having an injury and not being immobilized.

Here are some questions for the authors to consider before their presentation:

  • How did you define cervical injury, and why is the incidence in your study so much higher?
  • Do the prehospital agencies delivering patients to your center utilize the same clearance guidelines?
  • Big picture question: What should we do to make sure that cervical immobilization is applied appropriately?

Reference: EAST 2018 Podium abstract #34.

EAST 2018 #7: Cervical Spine Injury And Dysphagia

One of the under-appreciated complications of cervical spine fractures is dysphagia. This problem disproportionately affects the elderly, and is most common in patients with C1-C3 fractures. Swallowing becomes even more difficult when the head is held in position by a rigid cervical collar, which is the most common treatment for this injury.

How common is dysphagia in patients with cervical spine injury? What is the best way to detect it? These questions were asked by the group at MetroHealth Medical Center in Cleveland. They  retrospectively reviewed their experience with patients presenting with cervical spine injury for 14 months, then prospectively studied the use of routine, nurse-driven bedside dysphagia screening in similar patients for a year. They wanted to test the utility of screening, and judge its impact on outcome.

Here are the factoids:

  • 221 patients were prospectively studied and received a bedside dysphagia screen, but only 114 met all inclusion criteria and had the protocol properly followed (!)
  • 17% had dysphagia overall, with an incidence of 15% in cervical spine injuries and 31% in those with a concomitant spinal cord injury
  • The bedside dysphagia screen was 84% sensitive, 96% specific, with positive and negative predictive values of 80% and 97%, respectively
  • There were 6/214 patients with dysphagia complications in the retrospective group vs 0/114 in the screened group

Bottom line: This abstract actually puts a number on the incidence of dysphagia on this group of patients. I wish the patient numbers could have been higher, but they are still very good. The results are convincing, and the negative predictive value is excellent. If the screen is passed, then the patient should do well with feeds. I recommend that all patients with cervical spine injury treated with a rigid collar undergo this simple screen, and have appropriate diet adjustments to limit complications.

Here are some questions for the authors to consider before their presentation:

  • Please share the details of the nurse-driven component of the bedside dysphagia screen, and how you determine when a formal barium swallow is indicated
  • Why did your prospective study group drop from 221 to 114?
  • When did you typically perform the screen? Fracture swelling may not peak for 3 days, so early screening may not be as good as later screening.
  • This was a nice study, with a very practical and actionable result!

Reference: EAST Podium abstract #10.

A New Proposed Practice Guideline For Cervical Spine Clearance

In my last post, I reviewed a very recent prospective study on using CT scan alone for  cervical spine clearance in intoxicated patients. I believe that this is the final piece in the spine clearance puzzle to allow us to perform this task intelligently.

We’ve been accumulating more and more data that supports the use of CT scan in patients who fail clinical clearance. This failure can be due to the patient being obtunded or intoxicated, bearing a “distracting” injury, or being just plain uncooperative. Because of this, and our fear of missing a potentially devastating injury (typically because of rare anecdotal cases or urban legends), we have resorted to a significant degree of overkill. This has included, over the years, prolonged immobilization in a rigid collar, flexion/extension imaging (plain x-ray or fluoro), and MRI.

I’ve synthesized the available literature, and have drafted a simple, one sheet practice guideline for discussion. In order to use it, you must have the following:

  • A decent CT scanner – minimum 64 slice
  • A well-defined scan setup protocol – 3mm collimation, skull base to T2, 2-D reconstruction in sagittal and coronal planes (get a copy of our protocol below)
  • A skilled radiologist – neuroradiologist required

An image of the protocol can be found at the bottom of this post. I’m interested in your comments, and your comfort or discomfort with adopting something like this. Please leave comments here or on twitter.

Links: 

Reference: Cervical spine evaluation and clearance in the intoxicated patient: A prospective Western Trauma Association Multi-Institutional Trial and Survey. J Trauma 83(6):1032-1040, 2017.