Canadian C-Spine vs. NEXUS

Aidey

Aidey

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I'm looking for studies that investigate why the Canadian C-Spine Rule (CCSR) is more sensitive and more specific than NEXUS. Several studies have been done comparing the sensitivity and specificity of the two, but I can't find any explaining why there is a difference.
 
I'll stump through my literature in a bit, but the CCR adds sensitivity through its "age/mechanism" arm and includes a "low risk" filter to improve sensitivity by requiring midline cervical spine tenderness in the absence of neuro deficit.

NEXUS uses other qualifiers like intoxication or ALOC, where CCR uses GCS=15.

Intuitively this tells me they will have different sens/spec and that NEXUS casts a wider net thru usage of intox/ALOC/distracting but misses age/mechanism that CCR uses.
 
Yeah, but studies on mechanism have shown it to be an extremely poor predictor of actual injury. Maine used to use it in their version of NEXUS, but got rid of it after a few years because they found it had no correlation to actual injury.

NEXUS also requires a lack of midline cervical spine tenderness, so I don't think that is the difference, unless I'm not understanding what you are saying.
 
Aidey said:
Yeah, but studies on mechanism have shown it to be an extremely poor predictor of actual injury. Maine used to use it in their version of NEXUS, but got rid of it after a few years because they found it had no correlation to actual injury.

NEXUS also requires a lack of midline cervical spine tenderness, so I don't think that is the difference, unless I'm not understanding what you are saying.
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My lil NEXUS card just lists "midline spine tenderness", but looking it up shows that you're correct and it should state "midline cervical spine tenderness". Interesting omission, good thing we use CCR :)

CCR's mechanism clause is "high risk" like axial loading from diving injuries:
A dangerous mechanism is considered to be a fall from an elevation ≥3 ft or 5 stairs; an axial load to the head (e.g., diving); a motor vehicle collision at high speed (>100 km/hr) or with rollover or ejection; a collision involving a motorized recreational vehicle; or a bicycle collision.
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D'oh! I did read that study, but it probably would have helped if I had read the tables attached the first time around. Thanks.
 
Aidey said:
D'oh! I did read that study, but it probably would have helped if I had read the tables attached the first time around. Thanks.
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I've got a number of CCR vs NEXUS papers in my spinal collection and the replies by the docs from the original NEXUS standards are interesting in and of themselves.
 
I don't care too much about the efficacy of the CCR vs NEXUS, what I'm really interested in is why there is a difference. But I will check out what you posted, thanks.
 
Aidey said:
I don't care too much about the efficacy of the CCR vs NEXUS, what I'm really interested in is why there is a difference. But I will check out what you posted, thanks.
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Well, NEXUS was formed to validate Hoffman's criteria developed in the early 90's in a large population of patients. I don't have Hoffman's original paper and thus don't have the reasons (paging Dr. Oto). (edit: The validation paper features commentary from Hoffman which is Ok, apparently the NEXUS criteria were derived from small studies into features of "low risk" patients)

As for the CCR, Steill et al do a good job explaining why they sought to find better criteria:
The National Emergency X-Radiography Utilization Study (NEXUS) low-risk criteria for C-spine radiography were recently evaluated in a large study of EDs that found the criteria to be 99.6% sensitive for clinically important injuries. However, the specificity was only 12.9%, leading to concerns that use of the NEXUS criteria would actually increase the use of radiography in some US jurisdictions and in most countries outside of the United States.
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They collected a large chunk of data on 10k+ patients and did some statistical modeling to find a protocol which accounted for variables which independently predicted the need for imaging. The final 5 rules they settled on achieved the 100% sensitivity they were looking for and eked out an impressive 42% specificity in their cohort.

Basically, the items were chosen by pure numbers. One could argue since a number of the variables they studied were objective or subjective criteria per physicians that those choices showed some forethought, but ultimately it boiled down to simple logistic regression.

My assumption is Hoffman's criteria were arrived at in a similar fashion.
 
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This issue turned into a nice little measuring contest....The Stiell NEJM article was actually the first validation of the canadian rule, and I've always thought it was a bit overly competitive of our neighbors to the north to combine their first validation with an "ours is better" claim....

Anyhoo..

The back and forth between authors can be seen here:http://www.nejm.org/doi/full/10.1056/NEJMoa031375#t=letters

The editorial accompanying the canadian validation study is here, which addresses this issue head on (and is supportive of NEXUS):

http://sitemaker.umich.edu/emjourna...a.data/53938/PDF/nexus_ccr_nejm_editorial.pdf

aDr. Mower and Hoffman's (primary authors of NEXUS) respond again here:

http://www.downstate.edu/emergency_medicine/documents/CCSRvs.NEXUS-AEM04-04.pdf
 
Thanks guys, this is helpful.

I'm considering advocating for a combination of the two. NEXUS with a ROM test and possibly an age criteria that allows for the use of collars without LSBs in the elderly who lack symptoms.
 
No, in those cases the ROM test would be deferred. I'm thinking of elderly pts with neck pain, or who are unreliable due to dementia causing them to fail NEXUS. I would like to be able to use only a c collar without the backboard.

Edit: I should have been more clear in my previous post. The studies done with the CCR show there is an increased correlation between age and c-spine injury. Many of the elderly pts that end up on LSBs where I work would fail NEXUS because of the neck pain (often chronic) or because they are unreliable due to dementia or other issues. Rather than continuing to use full spinal motion restriction in this population, I would like to advocate for using just a c-collar in the cases that fail NEXUS because of one criteria, unless they have an acute neurological deficit.
 
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Christopher said:
I've got a number of CCR vs NEXUS papers in my spinal collection and the replies by the docs from the original NEXUS standards are interesting in and of themselves.
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Ok, now that I've had a chance to look at this on something other than my phone, you are officially my hero. I bequeath you 1 get out of jail free card*.
























































*Not really, because the administration here frowns on that sort of thing. But it is the thought that counts right?
 
Aidey said:
Ok, now that I've had a chance to look at this on something other than my phone, you are officially my hero. I bequeath you 1 get out of jail free card*.
Click to expand...

I am also now in love (A platonic, masculine and tough kind of love though). That looks like my folders on my computer, only organised, logical and coherent. I have 800 files in one folder alone, only I have no idea where to find most of my stuff.
 
If you send PM with an email address I can get you access to the rest of the collection.
 
I agree that keeping geriatric patients off the long board is probably good medicine, and definitely good for your immortal soul!

Given the know risks, many EMS agencies are eliminating the use of the spine board if patients are not severely injured. Xenia Fire, in Ohio, has a policy:"Do not transport a patient to the hospital on a backboard, short board, KED, or vacuum mattress unless it is necessary for patient safety." Only multi-system trauma gets a board. Or New Haven CT, that does not require boards for ambulatory trauma patients.

So many places already feel that there is sufficient evidence to forgo a board. Frankly, even with Christopher's library (Alexandrian in scale!), I don't think there is much in the c-spine literature that helps us directly with T&L spine stuff.
 
KellyBracket said:
I agree that keeping geriatric patients off the long board is probably good medicine, and definitely good for your immortal soul!

Given the know risks, many EMS agencies are eliminating the use of the spine board if patients are not severely injured. Xenia Fire, in Ohio, has a policy:"Do not transport a patient to the hospital on a backboard, short board, KED, or vacuum mattress unless it is necessary for patient safety." Only multi-system trauma gets a board. Or New Haven CT, that does not require boards for ambulatory trauma patients.

So many places already feel that there is sufficient evidence to forgo a board. Frankly, even with Christopher's library (Alexandrian in scale!), I don't think there is much in the c-spine literature that helps us directly with T&L spine stuff.
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(I certainly raced to build the Great Library of Alexandria whenever I played Civ II)

I think part of the problem in applying either the CCR or NEXUS is they are meant to determine who should receive imaging studies in order to identify high risk cervical spine injuries.

This is a nice surrogate for "who should we immobilize" as we're looking for the same sensitivity (100%).

As you noted, nowhere do these papers state how to immobilize what types of patients!

Perhaps the right answer for ambulatory patients with only ROM neck pain and no neuro deficits is no board and no collar, but they would still receive imaging in the ED.

We've got the tools to determine if they're low risk for imaging, but we don't necessarily have the tools to determine what is the appropriate amount/type of immobilization. I think we all agree some level of immobilization is appropriate...maybe?

(edit: I just realized North Carolina uses Dr. Weingart's "Canexus" protocol--most likely independently arrived--for Paramedics)
 
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Smash said:
I am also now in love (A platonic, masculine and tough kind of love though). That looks like my folders on my computer, only organised, logical and coherent. I have 800 files in one folder alone, only I have no idea where to find most of my stuff.
Click to expand...

Evernote, or some other program with optical character recognition (OCR). If you load your PDFs into a program with OCR it makes the PDFs searchable.

Christopher said:
If you send PM with an email address I can get you access to the rest of the collection.
Click to expand...

Done!

KellyBracket said:
I agree that keeping geriatric patients off the long board is probably good medicine, and definitely good for your immortal soul!

Given the know risks, many EMS agencies are eliminating the use of the spine board if patients are not severely injured. Xenia Fire, in Ohio, has a policy:"Do not transport a patient to the hospital on a backboard, short board, KED, or vacuum mattress unless it is necessary for patient safety." Only multi-system trauma gets a board. Or New Haven CT, that does not require boards for ambulatory trauma patients.

So many places already feel that there is sufficient evidence to forgo a board. Frankly, even with Christopher's library (Alexandrian in scale!), I don't think there is much in the c-spine literature that helps us directly with T&L spine stuff.
Click to expand...

I'm not Christian, but every time we force a little old lady in spinal motion restrictions I feel like I am going to be sent straight to hell and I should report myself for elder abuse.

We do not have a spinal clearance protocol nor do we have a protocol detailing under what circumstances we should be using spinal motion restriction. I've been told "follow the standard of care" <_<
 
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