The subaxial cervical spine injury classification system: a novel approach to recognize the importance of morphology, neurology, and integrity of the disco-ligamentous complex.
METHODS
The classification system was derived through a literature review and expert opinion of experienced spine surgeons. In addition, a multicenter reliability and validity study of the system was conducted on a collection of trauma cases.


OBJECTIVE
To define a novel classification system for subaxial cervical spine trauma that conveys information about injury pattern, severity, treatment considerations, and prognosis. To evaluate reliability and validity of this system.


BACKGROUND
Classification of subaxial cervical spine injuries remains largely descriptive, lacking standardization and prognostic information.


METHODS
Clinical and radiographic variables encountered in subaxial cervical trauma were identified by a working section of the Spine Trauma Study Group. Significant limitations of existing systems were defined and addressed within the new system. This system, as well as the Harris and Ferguson & Allen systems, was applied by 20 spine surgeons to 11 cervical trauma cases. Six weeks later, the cases were randomly reordered and again scored. Interrater reliability, intrarater reliability, and validity were assessed.


RESULTS
Each of 3 main categories (injury morphology, disco-ligamentous complex, and neurologic status) identified as integrally important to injury classification was assigned a weighted score; the injury severity score was obtained by summing the scores from each category. Treatment options were assigned based on threshold values of the severity score. Interrater agreement as assessed by intraclass correlation coefficient of the DLC, morphology, and neurologic status scores was 0.49, 0.57, and 0.87, respectively. Intrarater agreement as assessed by intraclass correlation coefficient of the DLC, morphology, and neurologic status scores was 0.66, 0.75, and 0.90, respectively. Raters agreed with treatment recommendations of the algorithm in 93.3% of cases, suggesting high construct validity. The reliability compared favorably to the Harris and Ferguson & Allen systems.


CONCLUSIONS
The Sub-axial Injury Classification and Severity Scale provides a comprehensive classification system for subaxial cervical trauma. Early validity and reliability data are encouraging.
Vaccaro
Alexander R
AR
Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, PA, USA. alexvaccaro3@aol.com
Hulbert
R John
RJ
Patel
Alpesh A
AA
Fisher
Charles
C
Dvorak
Marcel
M
Lehman
Ronald A
RA
Anderson
Paul
P
Harrop
James
J
Oner
F C
FC
Arnold
Paul
P
Fehlings
Michael
M
Hedlund
Rune
R
Madrazo
Ignacio
I
Rechtine
Glenn
G
Aarabi
Bizhan
B
Shainline
Mike
M
D002574:Cervical Vertebrae / Q000033:anatomy & histology / Q000293:injuries*; D006801:Humans; D015601:Injury Severity Score; D007403:Intervertebral Disc / Q000033:anatomy & histology / Q000293:injuries*; D009462:Neurology / Q000145:classification; D013124:Spinal Injuries / Q000145:classification* / Q000473:pathology*