Interobserver and Intraobserver Reliability of Sub-Axial Injury Classification and Severity Scale between Radiologist, Resident and Spine Surgeon

OBJECTIVE: The sub-axial injury classification (SLIC) and severity scale was developed to decide whether to operate the cervical injured patient or not, but the reliability of SLIC and severity scale among the different physicians was not well known. Therefore, we evaluated the reliability of SLIC among a spine surgeon, a resident of neurosurgery and a neuro-radiologist. METHODS: In retrograde review in single hospital from 2002 to 2009 years, 75 cases of sub-axial spine injured patients underwent operation. Each case was blindly reviewed for the SLIC and severity scale by 3 different observers by two times with 4 weeks interval with randomly allocated. The compared axis was the injury morphology score, the disco-ligamentous complex score, the neurological status score and total SLIC score; the neurological status score was derived from the review of medical record. The kappa value was used for the statistical analysis. RESULTS: Interobserver agreement of SLIC and severity scale was substantial agreement in the score of injury morphology [intraclass correlation (ICC)=0.603] and total SLIC and severity sacle (ICC value=0.775), but was fair agreement in the disco-ligamentous complex score (ICC value=0.304). Intraobserver agreements were almost perfect agreement in whole scales with ICC of 0.974 in a spine surgeon, 0.948 in a resident of neurosurgery, and 0.963 in a neuro-radiologist. CONCLUSION: The SLIC and severity scale is comprehensive and easily applicable tool in spine injured patient. Moreover, it is very useful tool to communicate among spine surgeons, residents of neurosurgery and neuro-radiologists with sufficient reproducibility.

Accuracy and Safety in Pedicle Screw Placement in the Thoracic and Lumbar Spines : Comparison Study between Conventional C-Arm Fluoroscopy and Navigation Coupled with O-Arm(R) Guided Methods

OBJECTIVE: The authors performed a retrospective study to assess the accuracy and clinical benefits of a navigation coupled with O-arm(R) system guided method in the thoracic and lumbar spines by comparing with a C-arm fluoroscopy-guided method. METHODS: Under the navigation guidance, 106 pedicle screws inserted from T7 to S1 in 24 patients, and using the fluoroscopy guidance, 204 pedicle screws from T5 to S1 in 45 patients. The position of screws within the pedicle was classified into four groups, from grade 0 (no violation cortex) to 3 (more than 4 mm violation). The location of violated pedicle cortex was also assessed. Intra-operative parameters including time required for preparation of screwing procedure, times for screwing and the number of X-ray shot were assessed in each group. RESULTS: Grade 0 was observed in 186 (91.2%) screws of the fluoroscopy-guided group, and 99 (93.4%) of the navigation-guided group. Mean time required for inserting a screw was 3.8 minutes in the fluoroscopy-guided group, and 4.5 minutes in the navigation-guided group. Mean time required for preparation of screw placement was 4 minutes in the fluoroscopy-guided group, and 19 minutes in the navigation-guided group. The fluoroscopy-guided group required mean 8.9 times of X-ray shot for each screw placement. CONCLUSION: The screw placement under the navigation-guidance coupled with O-arm(R) system appears to be more accurate and safer than that under the fluoroscopy guidance, although the preparation and screwing time for the navigation-guided surgery is longer than that for the fluoroscopy-guided surgery.