Open Posterior Reduction and Stabilization of AO Spine C3 Sacral Fractures.

AO Spine C3 sacral fractures are defined by separation of the spine including S1 from the pelvic ring and are usually result of a high-energy injury. Besides their high biomechanical instability and high rate of associated neurological impairment, these fractures are often extremely difficult to reduce due to severe bony impaction and dislocation. Additional difficulties in management of these fractures arise from only a thin-layer of soft-tissue coverage overlying the injured area

Comprehensive Mutation Analysis in Colorectal Flat Adenomas

Background: Flat adenomas are a subgroup of colorectal adenomas that have been associated with a distinct biology and a more aggressive clinical behavior compared to their polypoid counterparts. In the present study, we aimed to compare the mutation spectrum of 14 cancer genes, between these two phenotypes. Methods: A consecutive series of 106 flat and 93 polypoid adenomas was analyzed retrospectively for frequently occurring mutations in “hot spot” regions of KRAS, BRAF, PIK3CA and NRAS, as well as selected mutations in CTNNB1 (β-catenin), EGFR, FBXW7 (CDC4), PTEN, STK11, MAP2K4, SMAD4, PIK3R1 and PDGFRA using a high-throughput genotyping technique. Additionally, APC was analyzed using direct sequencing. Results: APC mutations were more frequent in polypoid adenomas compared to flat adenomas (48.5% versus 30.3%, respectively, p = 0.02). Mutations in KRAS, BRAF, NRAS, FBXW7 and CTNNB1 showed similar frequencies in both phenotypes. Between the different subtypes of flat adenomas (0-IIa, LST-F and LST-G) no differences were observed for any of the investigated genes. Conclusion: The lower APC mutation rate in flat adenomas compared to polypoid adenomas suggests that disruption of the Wnt-pathway may occur via different mechanisms in these two phenotypes. Furthermore, in contrast to previous observations our results in this large well-defined sample set indicate that there is no significant association between the different morphological phenotypes and mutations in key genes of the RAS-RAF-MAPK pathway

An international validation of the AO spine subaxial injury classification system.

PURPOSE To validate the AO Spine Subaxial Injury Classification System with participants of various experience levels, subspecialties, and geographic regions. METHODS A live webinar was organized in 2020 for validation of the AO Spine Subaxial Injury Classification System. The validation consisted of 41 unique subaxial cervical spine injuries with associated computed tomography scans and key images. Intraobserver reproducibility and interobserver reliability of the AO Spine Subaxial Injury Classification System were calculated for injury morphology, injury subtype, and facet injury. The reliability and reproducibility of the classification system were categorized as slight (ƙ = 0-0.20), fair (ƙ = 0.21-0.40), moderate (ƙ = 0.41-0.60), substantial (ƙ = 0.61-0.80), or excellent (ƙ = > 0.80) as determined by the Landis and Koch classification. RESULTS A total of 203 AO Spine members participated in the AO Spine Subaxial Injury Classification System validation. The percent of participants accurately classifying each injury was over 90% for fracture morphology and fracture subtype on both assessments. The interobserver reliability for fracture morphology was excellent (ƙ = 0.87), while fracture subtype (ƙ = 0.80) and facet injury were substantial (ƙ = 0.74). The intraobserver reproducibility for fracture morphology and subtype were excellent (ƙ = 0.85, 0.88, respectively), while reproducibility for facet injuries was substantial (ƙ = 0.76). CONCLUSION The AO Spine Subaxial Injury Classification System demonstrated excellent interobserver reliability and intraobserver reproducibility for fracture morphology, substantial reliability and reproducibility for facet injuries, and excellent reproducibility with substantial reliability for injury subtype

The Influence of Regional Differences on the Reliability of the AO Spine Sacral Injury Classification System.

STUDY DESIGN Global cross-sectional survey. OBJECTIVE To explore the influence of geographic region on the AO Spine Sacral Classification System. METHODS A total of 158 AO Spine and AO Trauma members from 6 AO world regions (Africa, Asia, Europe, Latin and South America, Middle East, and North America) participated in a live webinar to assess the reliability, reproducibility, and accuracy of classifying sacral fractures using the AO Spine Sacral Classification System. This evaluation was performed with 26 cases presented in randomized order on 2 occasions 3 weeks apart. RESULTS A total of 8320 case assessments were performed. All regions demonstrated excellent intraobserver reproducibility for fracture morphology. Respondents from Europe (k = .80) and North America (k = .86) achieved excellent reproducibility for fracture subtype while respondents from all other regions displayed substantial reproducibility. All regions demonstrated at minimum substantial interobserver reliability for fracture morphology and subtype. Each region demonstrated >90% accuracy in classifying fracture morphology and >80% accuracy in fracture subtype compared to the gold standard. Type C morphology (p2 = .0000) and A3 (p1 = .0280), B2 (p1 = .0015), C0 (p1 = .0085), and C2 (p1 =.0016, p2 =.0000) subtypes showed significant regional disparity in classification accuracy (p1 = Assessment 1, p2 = Assessment 2). Respondents from Asia (except in A3) and the combined group of North, Latin, and South America had accuracy percentages below the combined mean, whereas respondents from Europe consistently scored above the mean. CONCLUSIONS In a global validation study of the AO Spine Sacral Classification System, substantial reliability of both fracture morphology and subtype classification was found across all geographic regions

Development of Online Technique for International Validation of the AO Spine Subaxial Injury Classification System.

STUDY DESIGN Global cross-sectional survey. OBJECTIVE To develop and refine the techniques for web-based international validation of fracture classification systems. METHODS A live webinar was organized in 2018 for validation of the AO Spine Subaxial Injury Classification System, consisting of 35 unique computed tomography (CT) scans and key images with subaxial spine injuries. Interobserver reliability and intraobserver reproducibility was calculated for injury morphology, subtype, and facet injury according to the classification system. Based on the experiences from this webinar and incorporating rater feedback, adjustments were made in the organization and techniques used and in 2020 a repeat validation webinar was performed, evaluating images of 41 unique subaxial spine injuries. RESULTS In the 2018 session, the AO Spine Subaxial Injury Classification System demonstrated fair interobserver reliability for fracture subtype (κ = 0.35) and moderate reliability for fracture morphology and facet injury (κ=0.45, 0.43, respectively). However, in 2020, the interobserver reliability for fracture morphology (κ = 0.87) and fracture subtype (κ = 0.80) was excellent, while facet injury was substantial (κ = 0.74). Intraobserver reproducibility for injury morphology (κ =0.49) and injury subtype/facet injury were moderate (κ = 0.42) in 2018. In 2020, fracture morphology and subtype reproducibility were excellent (κ =0.85, 0.88, respectively) while reproducibility for facet injuries was substantial (κ = 0.76). CONCLUSION With optimized webinar-based validation techniques, the AO Spine Subaxial Injury Classification System demonstrated vast improvements in intraobserver reproducibility and interobserver reliability. Stringent fracture classification methodology is integral in obtaining accurate classification results

Effect of surgical experience and spine subspecialty on the reliability of the AO Spine Upper Cervical Injury Classification System.

OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience ( 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson's chi-square or Fisher's exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level ( 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 ( 20 years: 0.62), and only surgeons with > 20 years of experience did not have substantial reliability on assessment 2 ( 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system

The AO spine upper cervical injury classification system: Do work setting or trauma center affiliation affect classification accuracy or reliability?

PURPOSE To assess the accuracy and reliability of the AO Spine Upper Cervical Injury Classification System based on a surgeons' work setting and trauma center affiliation. METHODS A total of 275 AO Spine members participated in a validation of 25 upper cervical spine injuries, which were evaluated by computed tomography (CT) scans. Each participant was grouped based on their work setting (academic, hospital-employed, or private practice) and their trauma center affiliation (Level I, Level II or III, and Level IV or no trauma center). The classification accuracy was calculated as percent of correct classifications, while interobserver reliability, and intraobserver reproducibility were evaluated based on Fleiss' Kappa coefficient. RESULTS The overall classification accuracy for surgeons affiliated with a level I trauma center was significantly greater than participants affiliated with a level II/III center or a level IV/no trauma center on assessment one (p1<0.0001) and two (p2 = 0.0003). On both assessments, surgeons affiliated with a level I or a level II/III trauma center were significantly more accurate at identifying IIIB injury types (p1 = 0.0007; p2 = 0.0064). Academic surgeons and hospital employed surgeons were significantly more likely to correctly classify type IIIB injuries on assessment one (p1 = 0.0146) and two (p2 = 0.0015). When evaluating classification reliability, the largest differences between work settings and trauma center affiliations was identified in type IIIB injuries. CONCLUSION Type B injuries are the most difficult injury type to correctly classify. They are classified with greater reliability and classification accuracy when evaluated by academic surgeons, hospital-employed surgeons, and surgeons associated with higher-level trauma centers (I or II/III)

A Comparison of Radiographic Alignment between Bilateral and Unilateral Interbody Cages in Patients Undergoing Transforaminal Lumbar Interbody Fusion

Study Design Retrospective cohort study. Purpose: To compare radiographic outcomes between unilateral and bilateral cage placement in transforaminal lumbar interbody fusions (TLIF) and to determine if the rate of fusion at the 1-year postoperative point was different in patients who received bilateral versus unilateral cages. Overview of Literature There is no clear evidence to dictate whether bilateral or unilateral cages promote superior radiographic or surgical outcomes in TLIF. Methods: Patients \u3e18 years old who underwent primary one- or two-level TLIFs at our institution were identified and propensity-matched in a 3:1 fashion (unilateral:bilateral). Patient demographics, surgical characteristics, and radiographic outcomes, including vertebral endplate obliquity, segmental lordosis, subsidence, and fusion status, were compared between groups. Results: Of the 184 patients included, 46 received bilateral cages. Bilateral cage placement was associated with greater subsidence (1.06±1.25 mm vs. 0.59±1.16 mm, p=0.028) and enhanced restoration of segmental lordosis (5.74°±14.1° vs. −1.57°±10.9°, p=0.002) at the 1-year postoperative point, while unilateral cage placement was associated with an increased correction of endplate obliquity (−2.02°±4.42° vs. 0.24°±2.81°, p\u3c0.001). Bilateral cage placement was significantly associated with radiographic fusion on bivariate analysis (89.1% vs. 70.3%, p=0.018) and significantly predicted radiographic fusion on multivariable regression analysis (estimate, 1.35; odds ratio, 3.87; 95% confidence interval, 1.51–12.05; p=0.010). Conclusions: Bilateral interbody cage placement in TLIF procedures was associated with restoration of lumbar lordosis and increased fusion rates. However, endplate obliquity correction was significantly greater for patients who received a unilateral cage

Global Validation of the AO Spine Upper Cervical Injury Classification: Geographic Region Affects Reliability and Reproducibility.

STUDY DESIGN Global Survey. OBJECTIVE To determine the accuracy, interobserver reliability, and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeons' AO Spine region of practice (Africa, Asia, Central/South America, Europe, Middle East, and North America). METHODS A total of 275 AO Spine members assessed 25 upper cervical spine injuries and classified them according to the AO Spine Upper Cervical Injury Classification System. Reliability, reproducibility, and accuracy scores were obtained over two assessments administered at three-week intervals. Kappa coefficients (ƙ) determined the interobserver reliability and intraobserver reproducibility. RESULTS On both assessments, participants from Europe and North America had the highest classification accuracy, while participants from Africa and Central/South America had the lowest accuracy (P < .0001). Participants from Africa (assessment 1 (AS1):ƙ = .487; AS2:0.491), Central/South America (AS1:ƙ = .513; AS2:0.511), and the Middle East (AS1:0.591; AS2: .599) achieved moderate reliability, while participants from North America (AS1:ƙ = .673; AS2:0.648) and Europe (AS1:ƙ = .682; AS2:0.681) achieved substantial reliability. Asian participants obtained substantial reliability on AS1 (ƙ = .632), but moderate reliability on AS2 (ƙ = .566). Although there was a large effect size, the low number of participants in certain regions did not provide adequate certainty that AO regions affected the likelihood of participants having excellent reproducibility (P = .342). CONCLUSIONS The AO Spine Upper Cervical Injury Classification System can be applied with high accuracy, interobserver reliability, and intraobserver reproducibility. However, lower classification accuracy and reliability were found in regions of Africa and Central/South America, especially for severe atlas injuries (IIB and IIC) and atypical hangman's type fractures (IIIB injuries)