Prehospital Spinal Clearance Part I

An evidence-based approach...

It's no secret that I am a diehard advocate of progressive prehospital medicine. I am also a proponent of evidence-based medicine. Sometimes these two views can be conflicting because of the lack of evidence to back new medicine. I have often changed my views on certain treatments in light of new research. The outstanding presence of bias and valid arguments associated with medicine drives me to keep reading on, even after discovering what may seem like a correct answer. Looking in one place will never be an adequate solution to a complicated topic, at least this is true when it comes to medicine.

Here in my EMS system we practice evidence-based medicine. We also like to consider ourselves a pretty progressive organization. Our medical director gives us a lot of leeway, and holds us to a pretty high standard. You could see five different medics treat the same patient five different ways here in our system, and they will all have valid arguments for each treatment.

When it comes to a traumatic injury, backboards and neck collars are used at the discretion of the lead paramedic. I have seen paramedics that immobilize every patient they encounter that was involved in a car accident or any other blunt force traumatic event. I think this might be what we call CYA (cover your ass) procedures. These medics might have seen a missed spinal injury be improperly treated in their career, and an unfortunate victim of that care acquire a lifelong need for a wheelchair.

I have developed my own systematic approach to these trauma patients. Of coarse manual cervical spine immobilization is applied upon initial contact. If the patient is under the influence of alcohol, he/she gets the full package, board and collar. I have just had too many drunks that haven't felt a stab wound or broken arm, let-alone a possible spine injury. This is also a strong consideration with anyone who has recently taken analgesics or elicit drugs. If they aren't under the influence of drugs or alcohol I give an appropriate physical exam. I consider the mechanism of injury and touch the patient to assess for tenderness. If the patient is pain free, able to move all extremities, and rotate their head without pain or involuntary movement, they get to stay off the board. This isn't evidence-based and I have begun to question my own rational.

Luckily, I haven't had this go wrong. I pride myself in my assessment skills and appreciate the patient's comfort level. A backboard is a very uncomfortable bed cushion for someone who doesn't need it. Quite often, if they didn't have pain to begin with, they will after being on a backboard for only a few minutes. Of coarse, muscle pains from being on a hard board is nothing in comparison to chronic paralysis from being mishandled; I can also appreciate this fact.

Recently I read a statement on Trauma.org that has sparked yet another need for further information gathering[1]:

There is no conclusive evidence in the literature that supports clinical clearance of the spine in the prehospital environment. There is enough variation between prehospital and in-hospital assessments to recommend that prehospital removal of spinal immobilisation be avoided.

This is a pretty blunt statement; no conclusive evidence, not any? What is Trauma.org's definition of conclusive, I wonder. I know there must be something out there that supports the paramedic's ability to adequately assess their patient and make a decision like this. I also wonder if the statement is made only in regards to removal of previously applied spinal immobilization. What kind then, manual immobilization or the whole package? Or is this statement in regards to all blunt trauma patients; should we immobilize them all? Maybe they are referring to only neck and/or back pain patients. The list of questions has quickly become a long one, luckily the authors listed their sources.

The first source listed is from a journal that I personally subscribe to, Prehospital Emergency Care. Unfortunately, this is from 1999 and I don't have the issue. I used Medline to find the article but was only able to come up with the abstract. Here is the abstract from the cited study[2]:

INTRODUCTION: Traditional EMS teaching identifies mechanism of injury as an important predictor of spinal injury. Clinical criteria to select patients for immobilization are being studied in Michigan and have been implemented in Maine. Maine requires automatic immobilization of patients with "a positive mechanism" clearly capable of producing spinal injury. OBJECTIVE: To determine whether mechanism of injury affects the ability of clinical criteria to identify patients with spinal injury. METHODS: In this multicenter prospective cohort study, EMS personnel completed a check-off data sheet for prehospital spine-immobilized patients. Data included mechanism of injury and yes/no determinations of the clinical criteria: altered mental status, neurologic deficit, evidence of intoxication, spinal pain or tenderness, and suspected extremity fracture. Hospital outcome data included confirmation of spinal injury and treatment required. Mechanisms of injury were tabulated and rates of spinal injury for each mechanism were calculated. The patients were divided into three different high-risk and low-risk groups. RESULTS: Data were collected for 6,500 patients. There were 209 (3.2%) patients with spinal injuries identified. There were 1,058 patients with 100 (9.4%) injuries in the first high-risk mechanism group, and 5,423 patients with 109 (2%) injuries in the first low-risk group. Criteria identified 97 of 100 (97%) injuries in the high-risk group and 102 of 109 (94%) in the low-risk group. Two additional data divisions yielded identical results. CONCLUSION: Mechanism of injury does not affect the ability of clinical criteria to predict spinal injury in this population.

So the first thing that stands out to me is the year the study was done. 1999 was 10 years ago. Sure, it isn't that long ago, but think of how much things change in the medical field in a matter of a few years. That doesn't mean that the data isn't valid though. The next thing that stands out is the study itself. It is questioning the relevance of mechanism of injury(MOI)in determining a cervical spine injury, not the ability of a paramedic to adequately clear a cervical spine.

This study gave the paramedics a set list of criteria, it didn't expand off of the paramedic's assessment skill. The study used paramedics in their research, but they were not testing the medics, just the method. So if the criteria were invalid, how does this reflect on the assessment skill of a paramedic?

Unfortunately this abstract leads a lot to the imagination. I'm not sure if the low risk group was intended to be injury free and ended up with 94% of them having injuries (highly unlikely). It seems to me like their low risk criteria appropriately identified 94% of the injuries and the high risk criteria caught 97% of the injuries. That seems to have pretty good specificity to me. I am still looking for the full text for this study (hint hint Rogue Medic).

The conclusion pretty much states that MOI does not effect clinical criteria when predicting spinal cord injury. Does this mean that a possible spinal cord injury is not at all predictable by the MOI. I didn't find conclusive evidence (be it just an abstract) that states paramedics should not be clinically clearing the cervical spine in the field.

That isn't exactly what I am looking for though. Without evidence of benifit, we wouldn't be practicing evidence-based medicine. The next refference that Trauma.org cited was a study from The Journal of Trauma. Once again, all I could find (even in my college's extensive database) was the abstract[3]:

OBJECTIVE: Determine the level of agreement between emergency medical technicians (EMTs) and emergency physicians (EPs) when applying an existing emergency medical services/fire department protocol for out-of-hospital clinical cervical spine injury (CSI) clearance in blunt trauma patients. METHODS: Prospective observational study of consecutive blunt trauma patients transported by emergency medical services/fire department during a 3-month study period. The setting was an urban Level I trauma center. Measurement of interrater agreement (kappa) was determined. RESULTS: Mean age of the 190 patients was 34+/-19 years (range, 6 -98 years). Fifty-nine percent of the patients were male. One hundred forty-six patients (77%) were immobilized by EMTs; 17 of these patients were clinically cleared by EPs. Forty-four patients (23%) were clinically cleared by EMTs and presented without CSI precautions; of these, 61% (27 of 44) were immobilized by EPs and 57% (25 of 44) had cervical spine radiographs obtained. Overall, 141 patients (74%) required radiographic clearance. CSI were detected in five patients (2.6%); all five were immobilized in the out-of-hospital setting. Overall disagreement between EMTs and EPs regarding out-of-hospital CSI clearance occurred in 44 patients (23%) (kappa=0.29; 95% confidence interval, 0.15-0.43; p less than 0.01). CONCLUSION: Significant disagreement in clinical CSI clearance exists between EMTs and EPs. Further research and education is recommended before widespread implementation of this practice.

An even older study, done in 1998, but the data is still relevant (also, keep in mind, the Trauma.org article is from 2002). This study doesn't disprove the ability of paramedics, or EMTs for that matter, to clincally clear a cervical spine. This abstract questions whether EMTs and emergency physicians agree. I hate to point this out, but according to the abstract, the EMTs properly immobilized every patient that came back with a positive cervical spine injury. This doesn't disprove the purpose of the study however. What I get out of this is the need for the emergency physicians to be on board with a prehospital spinal clearanace protocol.

These were the only two references cited by Trauma.org. Neither reference seems to disprove the ability of an EMT to clinically clear the cervical spine. What was the original statement in question though?

There is no conclusive evidence in the literature that supports clinical clearance of the spine in the prehospital environment. There is enough variation between prehospital and in-hospital assessments to recommend that prehospital removal of spinal immobilisation be avoided.

We still don't have the conclusive evidence to support cervical spine clearance. One abstract questioned the relationship between MOI and cervical spine injuries. The other study states that physicians and EMTs disagree, but that isn't necessarily a definitive reason to avoid prehospital clearance of the cervical spine. Just because the studies were both conducted in the prehospital environment doesn't mean that they tested the ability of the prehospital personnel.

Part II will include my own research on this topic.

Works Cited

[1]Brohi K. 2002. "Clinical Clearance of Cervical Spine Injury" Trauma.org, Link to article

[2]Domeier RM, Evans RW, Swor RA, Hancock JB, Fales W, Krohmer J, Frederiksen SM, and Shork MA. 1999. "The reliability of prehospital clinical evaluation for potential spinal injury is not affected by the mechanism of injury." Prehospital Emergency Care: Official Journal Of The National Association Of EMS Physicians And The National Association Of State EMS Directors 3, no. 4: 332-337. MEDLINE with Full Text, EBSCOhost (accessed May 30, 2009).

[3]Meldon SW, Brant TA, Cydulka RK, Collins TE, and Shade BR. 1998. "Out-of-hospital cervical spine clearance: agreement between emergency medical technicians and emergency physicians." The Journal Of Trauma 45, no. 6: 1058-1061. MEDLINE with Full Text, EBSCOhost (accessed May 30, 2009).