Any patient with a suspected cervical spine injury and a neurologic deficit should have a cervical collar in place, and should be referred immediately for neurosurgical or orthopedic spine consultation and imaging. All other patients who have indications for prehospital cervical collar placement as detailed above with the Canadian C-Spine Rule should undergo cervical spine clearance by the appropriate algorithm. There are separate algorithms for reliable (Appendix E) and unreliable (Appendix F) patients. Unreliable patients are those who cannot adequately communicate, have a decreased level of consciousness (GCS<15), or have a significant distracting injury. However, controversy exists about the clinical importance of distracting injuries.
Significant distracting injury is technically defined as any injury, which is so painful that it may obscure the patient’s ability to notice pain in their neck. The treating physician makes the final determination whether a certain injury is distracting enough to render a patient unreliable and require clearance via the unreliable patient algorithm. The rate of missed injury in the presence of a distracting injury is above 12%, but has not been shown to be significantly higher than in patients without distracting injuries.18,19 However, if uncertain, err on the side of caution and consider the injury distracting and proceed accordingly. Clearing the C-spine in this scenario requires good communication with the next echelon of care (Appendix G: Cervical Spine Clearance Status) or defer to that level of care for clearance.
See Appendix E and Appendix F for protocol diagrams. If possible, the cervical spine should be cleared and the collar removed within 24 hours of collar placement. If the clinical scenario requires that the collar remain in place more than 24 hours, stiff extrication collars should be replaced with collars designed for long-term immobilization that provide greater padding and decubitus ulcer prevention.
CERVICAL SPINE CLEARANCE IN THE OBTUNDED PATIENT
Cervical spine clearance in the obtunded patient is highly controversial and presents additional challenges to the clinician, especially in the combat environment.15,17,20 Obtunded patients with a concerning mechanism of injury should undergo CT of the spine with fine cuts and multi-planar reconstructed images (3 mm axial, 3 mm coronal and 2 mm sagittal views). If CT is unavailable or unobtainable, full C-Spine plain radiographs (adequate AP, lateral and odontoid) should be performed.21 Flexion/extension radiography should not be performed in a patient who cannot be simultaneously examined for the development of neurological signs or symptoms. Ultimately, clearance of the cervical spine in the obtunded patient should be left to clinical decision making of the highest level of care the patient is evacuated to who will be providing their longer term care.
For the obtunded patient with negative imaging, the incidence of significant cervical instability is low. It has generally been accepted that occult ligamentous injury is only cleared through a reliable clinical examination with a cooperative, extubated patient or magnetic resonance imaging (MRI). However, recent literature suggests that a high quality negative CT scan may be enough to remove the cervical collar.22 This protocol has become the new standard to follow in several high-level acute civilian trauma centers and supports the guideline to forego an MRI as a requirement to clear an obtunded patient, per the Eastern Association for the Surgery of Trauma Practice Management Guideline.22
“[I]n obtunded adult blunt trauma patients, cervical collars should be removed after a negative high-quality C-spine CT result alone. This recommendation is based on the finding that there is a worst-case 9% cumulative literature incidence of stable injuries and a 91% negative predictive value of no injury, after coupling a negative high-quality C-spine CT result with 1.5-T MRI, upright x-ray series, flexion-extension CT, and/or clinical follow-up. Similarly, there is a best-case 0% cumulative literature incidence of unstable C-spine injuries after negative initial imaging result with a high-quality C-spine CT.”
As such, with a high quality CT scan negative for fractures, this method of clearance may be utilized in patients who have arrived at their definitive level of care.
There is risk for significant neck movements in obtunded patients while transiting through the aeromedical evacuation system, so it is recommended that they remain with cervical spine immobilization until arrival at their definitive level of care. The incidence of occipital skin breakdown has decreased with the utilization of collars with greater padding (e.g., Miami-J with Occian back) and increased trauma system awareness of this potential complication.
The clinical decision to definitively clear the cervical spine without exclusion of ligamentous injury by either a reliable clinical examination or a MRI should be left to the level of care providing definitive treatment to the patient. Historically, given the challenges and multiple hand-offs inherent to echeloned care, a “2 out of 3” rule for cervical clearance in the obtunded patient has been Landstuhl Regional Medical Center/Role 4 policy since 2011. This rule requires negative results of 2 of 3 modalities (CT, MRI, clinical exam) prior to removing rigid cervical collars in obtunded patients. Given the low, but non-zero, incidence of significant cervical injury missed on standard 3-plane CT scan, it is recommended that when applying the 2 out of 3 rule, that the obtunded patient be transitioned from the traditional rigid collars to a memory foam enhanced rigid collar if available (i.e. Miami-J with Occian back) until either a reliable clinical examination or MRI can be obtained.22-25 This method helps to decrease the risk of an occipital decubitus ulcer in those patients with a low likelihood of cervical spine injury who are still in transport and have not yet arrived at their level of definitive care.
Determination of when to image the whole spine (occiput to sacrum) versus selective imaging is based on the mechanism of injury, the physical/neurological exam, as well as the mental status of the patient. Patients who have one identifiable fracture in the spine should have their entire spine imaged. Certain mechanisms of injury, such as a mounted blast, should also warrant imaging of the whole spine.
CERVICAL SPINE CLEARANCE DOCUMENTATION
It is recommended that the JTS Cervical Spine Clearance Status Sheet (Appendix G) or Trauma Resuscitation Record (DD Form 3019) be used for documenting the cervical spine evaluation and clearance status. This comprehensive worksheet includes indications for clearance, exam, imaging studies, and final clearance status. It is intended to bring together all cervical spine information onto one sheet of paper and was designed to improve both the completeness and ease of documentation.
PATIENTS UNABLE TO TRANSFER FROM THEATER
The optimal management of host nationals and others unable to transfer is problematic in the austere environment. The availability to obtain CT or transfer the patient to a facility with CT can make spine evaluation and clearance challenging, with reliance on plain radiographs and physical examination. Sound clinical judgment, remote consultation with a spine surgeon (if available), as well as consultation with theater rules of eligibility are of benefit to decision making.