Validation of the AO Spine CROST (Clinician Reported Outcome Spine Trauma) in the clinical setting.

PURPOSE: To evaluate feasibility, internal consistency, inter-rater reliability, and prospective validity of AO Spine CROST (Clinician Reported Outcome Spine Trauma) in the clinical setting. METHODS: Patients were included from four trauma centers. Two surgeons with substantial amount of experience in spine trauma care were included from each center. Two separate questionnaires were administered at baseline, 6-months and 1-year: one to surgeons (mainly CROST) and another to patients (AO Spine PROST-Patient Reported Outcome Spine Trauma). Descriptive statistics were used to analyze patient characteristics and feasibility, Cronbach's α for internal consistency. Inter-rater reliability through exact agreement, Kappa statistics and Intraclass Correlation Coefficient (ICC). Prospective analysis, and relationships between CROST and PROST were explored through descriptive statistics and Spearman correlations. RESULTS: In total, 92 patients were included. CROST showed excellent feasibility results. Internal consistency (α = 0.58-0.70) and reliability (ICC = 0.52 and 0.55) were moderate. Mean total scores between surgeons only differed 0.2-0.9 with exact agreement 48.9-57.6%. Exact agreement per CROST item showed good results (73.9-98.9%). Kappa statistics revealed moderate agreement for most CROST items. In the prospective analysis a trend was only seen when no concerns at all were expressed by the surgeon (CROST = 0), and moderate to strong positive Spearman correlations were found between CROST at baseline and the scores at follow-up (rs = 0.41-0.64). Comparing the CROST with PROST showed no specific association, nor any Spearman correlations (rs = -0.33-0.07). CONCLUSIONS: The AO Spine CROST showed moderate validity in a true clinical setting including patients from the daily clinical practice.

Understanding Decision Making as It Influences Treatment in Thoracolumbar Burst Fractures Without Neurological Deficit: Conceptual Framework and Methodology.

STUDY DESIGN: This paper presents a description of a conceptual framework and methodology that is applicable to the manuscripts that comprise this focus issue. OBJECTIVES: Our goal is to present a conceptual framework which is relied upon to better understand the processes through which surgeons make therapeutic decisions around how to treat thoracolumbar burst fractures (TL) fractures. METHODS: We will describe the methodology used in the AO Spine TL A3/4 Study prospective observational study and how the radiographs collected for this study were utilized to study the relationships between various variables that factor into surgeon decision making. RESULTS: With 22 expert spine trauma surgeons analyzing the acute CT scans of 183 patients with TL fractures we were able to perform pairwise analyses, look at reliability and correlations between responses and develop frequency tables, and regression models to assess the relationships and interactions between variables. We also used machine learning to develop decision trees. CONCLUSIONS: This paper outlines the overall methodological elements that are common to the subsequent papers in this focus issue.

Using Equipoise to Determine the Radiographic Characteristics Leading to Agreement on Best Treatment for Thoracolumbar Burst Fractures Without Neurologic Deficits.

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVES: Our goal was to assess radiographic characteristics associated with agreement and disagreement in treatment recommendation in thoracolumbar (TL) burst fractures. METHODS: A panel of 22 AO Spine Knowledge Forum Trauma experts reviewed 183 cases and were asked to: (1) classify the fracture; (2) assess degree of certainty of PLC disruption; (3) assess degree of comminution; and (4) make a treatment recommendation. Equipoise threshold used was 77% (77:23 distribution of uncertainty or 17 vs 5 experts). Two groups were created: consensus vs equipoise. RESULTS: Of the 183 cases reviewed, the experts reached full consensus in only 8 cases (4.4%). Eighty-one cases (44.3%) were included in the agreement group and 102 cases (55.7%) in the equipoise group. A3/A4 fractures were more common in the equipoise group (92.0% vs 83.7%, P < .001). The agreement group had higher degree of certainty of PLC disruption [35.8% (SD 34.2) vs 27.6 (SD 27.3), P < .001] and more common use of the M1 modifier (44.3% vs 38.3%, P < .001). Overall, the degree of comminution was slightly higher in the equipoise group [47.8 (SD 20.5) vs 45.7 (SD 23.4), P < .001]. CONCLUSIONS: The agreement group had a higher degree of certainty of PLC injury and more common use of M1 modifier (more type B fractures). The equipoise group had more A3/A4 type fractures. Future studies are required to identify the role of comminution in decision making as degree of comminution was slightly higher in the equipoise group.

Predictive Algorithm for Surgery Recommendation in Thoracolumbar Burst Fractures Without Neurological Deficits.

STUDY DESIGN: Predictive algorithm via decision tree. OBJECTIVES: Artificial intelligence (AI) remain an emerging field and have not previously been used to guide therapeutic decision making in thoracolumbar burst fractures. Building such models may reduce the variability in treatment recommendations. The goal of this study was to build a mathematical prediction rule based upon radiographic variables to guide treatment decisions. METHODS: Twenty-two surgeons from the AO Knowledge Forum Trauma reviewed 183 cases from the Spine TL A3/A4 prospective study (classification, degree of certainty of posterior ligamentous complex (PLC) injury, use of M1 modifier, degree of comminution, treatment recommendation). Reviewers' regions were classified as Europe, North/South America and Asia. Classification and regression trees were used to create models that would predict the treatment recommendation based upon radiographic variables. We applied the decision tree model which accounts for the possibility of non-normal distributions of data. Cross-validation technique as used to validate the multivariable analyses. RESULTS: The accuracy of the model was excellent at 82.4%. Variables included in the algorithm were certainty of PLC injury (%), degree of comminution (%), the use of M1 modifier and geographical regions. The algorithm showed that if a patient has a certainty of PLC injury over 57.5%, then there is a 97.0% chance of receiving surgery. If certainty of PLC injury was low and comminution was above 37.5%, a patient had 74.2% chance of receiving surgery in Europe and Asia vs 22.7% chance in North/South America. Throughout the algorithm, the use of the M1 modifier increased the probability of receiving surgery by 21.4% on average. CONCLUSION: This study presents a predictive analytic algorithm to guide decision-making in the treatment of thoracolumbar burst fractures without neurological deficits. PLC injury assessment over 57.5% was highly predictive of receiving surgery (97.0%). A high degree of comminution resulted in a higher chance of receiving surgery in Europe or Asia vs North/South America. Future studies could include clinical and other variables to enhance predictive ability or use machine learning for outcomes prediction in thoracolumbar burst fractures.

Interobserver Reliability in the Classification of Thoracolumbar Fractures Using the AO Spine TL Injury Classification System Among 22 Clinical Experts in Spine Trauma Care.

STUDY DESIGN: Reliability study utilizing 183 injury CT scans by 22 spine trauma experts with assessment of radiographic features, classification of injuries and treatment recommendations. OBJECTIVES: To assess the reliability of the AOSpine TL Injury Classification System (TLICS) including the categories within the classification and the M1 modifier. METHODS: Kappa and Intraclass correlation coefficients were produced. Associations of various imaging characteristics (comminution, PLC status) and treatment recommendations were analyzed through regression analysis. Multivariable logistic regression modeling was used for making predictive algorithms. RESULTS: Reliability of the AO Spine TLICS at differentiating A3 and A4 injuries (N = 71) (K = .466; 95% CI .458 - .474; P < .001) demonstrated moderate agreement. Similarly, the average intraclass correlation coefficient (ICC) amongst A3 and A4 injuries was excellent (ICC = .934; 95% CI .919 - .947; P < .001) and the ICC between individual measures was moderate (ICC = .403; 95% CI .351 - .461; P < .001). The overall agreement on the utilization of the M1 modifier amongst A3 and A4 injuries was fair (K = .161; 95% CI .151 - .171; P < .001). The ICC for PLC status in A3 and A4 injuries averaged across all measures was excellent (ICC = .936; 95% CI .922 - .949; P < .001). The M1 modifier suggests respondents are nearly 40% more confident that the PLC is injured amongst all injuries. The M1 modifier was employed at a higher frequency as injuries were classified higher in the classification system. CONCLUSIONS: The reliability of surgeons differentiating between A3 and A4 injuries in the AOSpine TLICS is substantial and the utilization of the M1 modifier occurs more frequently with higher grades in the system.

Expert Opinion, Real-World Classification, and Decision-Making in Thoracolumbar Burst Fractures Without Neurologic Deficits?

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVES: To compare decision-making between an expert panel and real-world spine surgeons in thoracolumbar burst fractures (TLBFs) without neurological deficits and analyze which factors influence surgical decision-making. METHODS: This study is a sub-analysis of a prospective observational study in TL fractures. Twenty two experts were asked to review 183 CT scans and recommend treatment for each fracture. The expert recommendation was based on radiographic review. RESULTS: Overall agreement between the expert panel and real-world surgeons regarding surgery was 63.2%. In 36.8% of cases, the expert panel recommended surgery that was not performed in real-world scenarios. Conversely, in cases where the expert panel recommended non-surgical treatment, only 38.6% received non-surgical treatment, while 61.4% underwent surgery. A separate analysis of A3 and A4 fractures revealed that expert panel recommended surgery for 30% of A3 injuries and 68% of A4 injuries. However, 61% of patients with both A3 and A4 fractures received surgery in the real world. Multivariate analysis demonstrated that a 1% increase in certainty of PLC injury led to a 4% increase in surgery recommendation among the expert panel, while a .2% increase in the likelihood of receiving surgery in the real world. CONCLUSION: Surgical decision-making varied between the expert panel and real-world treating surgeons. Differences appear to be less evident in A3/A4 burst fractures making this specific group of fractures a real challenge independent of the level of expertise.

The Influence of Comminution and Posterior Ligamentous Complex Integrity on Treatment Decision Making in Thoracolumbar Burst Fractures Without Neurologic Deficit?

STUDY DESIGN: A prospective study. OBJECTIVE: to evaluate the impact of vertebral body comminution and Posterior Ligamentous Complex (PLC) integrity on the treatment recommendations of thoracolumbar fractures among an expert panel of 22 spine surgeons. METHODS: A review of 183 prospectively collected thoracolumbar burst fracture computed tomography (CT) scans by an expert panel of 22 trauma spine surgeons to assess vertebral body comminution and PLC integrity. This study is a sub-study of a prospective observational study of thoracolumbar burst fractures (Spine TL A3/A4). Each expert was asked to grade the degree of comminution and certainty about the PLC disruption from 0 to 100, with 0 representing the intact vertebral body or intact PLC and 100 representing complete comminution or complete PLC disruption, respectively. RESULTS: ≥45% comminution had a 74% chance of having surgery recommended, while <25% comminution had an 86.3% chance of non-surgical treatment. A comminution from 25 to 45% had a 57% chance of non-surgical management. ≥55% PLC injury certainity had a 97% chance of having surgery, and ≥45-55% PLC injury certainty had a 65%. <20% PLC injury had a 64% chance of having non-operative treatment. A 20 to 45% PLC injury certainity had a 56% chance of non-surgical management. There was fair inter-rater agreement on the degree of comminution (ICC .57 [95% CI 0.52-.63]) and the PLC integrity (ICC .42 [95% CI 0.37-.48]). CONCLUSION: The study concludes that vetebral comminution and PLC integrity are major dterminant in decision making of thoracolumbar fractures without neurological deficit. However, more objective, reliable, and accurate methods of assessment of these variables are warranted.

Non-linear Effect of Preexisting Cranial Adjacent Disc Degeneration on Cumulative 12-year Revision Risk Following Lumbar Fusions.

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVE: To evaluate how preexisting adjacent segment degeneration status impacts revision risk for adjacent segment disease (ASD) after lumbar fusions. SUMMARY OF BACKGROUND DATA: ASD incurs late reoperations after lumbar fusion surgeries. ASD pathogenesis is multifactorial. Preexisting adjacent segment degeneration measured by Pfirrmann is suggested as one of the predisposing factors. We sought to find deeper insights into this association by using a more granular degeneration measure, the Combined imaging score (CIS). METHODS: A total of 197 consecutive lumbar fusions for degenerative pathologies were enrolled in a prospective follow-up (median 12 years). Preoperative cranial adjacent segment degeneration status was determined using Pfirrmann and CIS, which utilizes both radiographs and magnetic resonance imaging. Based on CIS, patients were trichotomized into tertiles (CIS <7, CIS 7-10, and CIS >10). The cumulative ASD revision risk was determined for each tertile. After adjusting for age, sex, body mass index, sacral fixation, and fusion length, hazard ratios (95% confidence intervals, CI) for ASD revisions were determined for each Pfirrmann and CIS score. RESULTS: Patients in the intermediate CIS tertile had a cumulative ASD revision risk of 25.4% (17.0% to 37.0%), while both milder degeneration (CIS <7) [13.2% (6.5% to 25.8%)] and end-stage degeneration (CIS >10) [13.6% (7.0% to 25.5%)] appeared to be protective against surgical ASD. Pfirrmann failed to show a significant association with ASD revision risk. Adjusted analysis of CIS suggested increased ASD revisions after CIS 7, which turned contrariwise after CIS 10. CONCLUSIONS: The effect of preexisting adjacent segment degeneration on ASD reoperation risk is not linear. The risk seems to increase with advancing degeneration but diminish with end-stage degeneration. Therefore, end-stage degenerative segments may be considered to be excluded from fusion constructs. LEVEL OF EVIDENCE: Therapeutic Level III.

Supplementary value and diagnostic performance of computed tomography scout view in the detection of thoracolumbar spine injuries.

PURPOSE: Assessing the diagnostic performance and supplementary value of whole-body computed tomography scout view (SV) images in the detection of thoracolumbar spine injuries in early resuscitation phase and identifying frequent image quality confounders. METHODS: In this retrospective database analysis at a tertiary emergency center, three blinded senior experts independently assessed SV to detect thoracolumbar spine injuries. The findings were categorized according to the AO Spine classification system. Confounders impacting SV image quality were identified. The suspected injury level and severity, along with the confidence level, were indicated. Diagnostic performance was estimated using the caret package in R programming language. RESULTS: We assessed images of 199 patients, encompassing 1592 vertebrae (T10-L5), and identified 56 spinal injuries (3.5%). Among the 199 cases, 39 (19.6%) exhibited at least one injury in the thoracolumbar spine, with 12 (6.0%) of them displaying multiple spinal injuries. The pooled sensitivity, specificity, and accuracy were 47%, 99%, and 97%, respectively. All experts correctly identified the most severe injury of AO type C. The most common image confounders were medical equipment (44.6%), hand position (37.6%), and bowel gas (37.5%). CONCLUSION: SV examination holds potential as a valuable supplementary tool for thoracolumbar spinal injury detection when CT reconstructions are not yet available. Our data show high specificity and accuracy but moderate sensitivity. While not sufficient for standalone screening, reviewing SV images expedites spinal screening in mass casualty incidents. Addressing modifiable factors like medical equipment or hand positioning can enhance SV image quality and assessment.

An Assessment of the World's Contribution to Spine Trauma Care: A Bibliometric Analysis of Classifications and Surgical Management; An AO Spine Knowledge Forum Trauma Initiative.

STUDY DESIGN: Bibliometric analysis. OBJECTIVES: An analysis of the literature related to the assessment and management of spinal trauma was undertaken to allow the identification of top contributors, collaborations and research trends. METHODS: A search to identify original articles published in English between 2011 and 2020 was done using specific keywords in the Web of Science database. After screening, the top 300 most cited articles were analyzed using Biblioshiny R software. RESULTS: The highest number of contributions were from the Thomas Jefferson University, USA, University of Toronto and University of British Columbia, Canada. The top 3 most prolific authors were Vaccaro AR, Arabi B, and Oner FC. The USA and Canada were among the top contributing countries; Switzerland and Brazil had most multiple country co-authored articles. The most relevant journals were the European Spine Journal, Spine and Spine Journal. Three of the 5 most cited articles were about classification systems of fractures. The keyword analysis included clusters for different spinal regions, spinal cord injury, classification agreement and reliability studies, imaging related studies, surgical techniques and outcomes. CONCLUSIONS: The study identified the most impactful authors and affiliations, and determined the journals where most impactful research is published in the field. Study also compared the productivity and collaborations across countries. The study highlighted the impact of development of new classification systems, and identified research trends including instrumentation, fixation and decompression techniques, epidemiology and recovery after spinal trauma.

The Diagnostic Process of Spinal Post-traumatic Deformity: An Expert Survey of 7 Cases, Consensus on Clinical Relevance Does Exist.

STUDY DESIGN: Survey of cases. OBJECTIVE: To evaluate the opinion of experts in the diagnostic process of clinically relevant Spinal Post-traumatic Deformity (SPTD). SUMMARY OF BACKGROUND DATA: SPTD is a potential complication of spine trauma that can cause decreased function and quality of life impairment. The question of when SPTD becomes clinically relevant is yet to be resolved. METHODS: The survey of 7 cases was sent to 31 experts. The case presentation was medical history, diagnostic assessment, evaluation of diagnostic assessment, diagnosis, and treatment options. Means, ranges, percentages of participants, and descriptive statistics were calculated. RESULTS: Seventeen spinal surgeons reviewed the presented cases. The items' fracture type and complaints were rated by the participants as more important, but no agreement existed on the items of medical history. In patients with possible SPTD in the cervical spine (C) area, participants requested a conventional radiograph (CR) (76%-83%), a flexion/extension CR (61%-71%), a computed tomography (CT)-scan (76%-89%), and a magnetic resonance (MR)-scan (89%-94%). In thoracolumbar spine (ThL) cases, full spine CR (89%-100%), CT scan (72%-94%), and MR scan (65%-94%) were requested most often. There was a consensus on 5 out of 7 cases with clinically relevant SPTD (82%-100%). When consensus existed on the diagnosis of SPTD, there was a consensus on the case being compensated or decompensated and being symptomatic or asymptomatic. CONCLUSIONS: There was strong agreement in 5 out of 7 cases on the presence of the diagnosis of clinically relevant SPTD. Among spine experts, there is a strong consensus to use CT scan and MR scan, a cervical CR for C-cases, and a full spine CR for ThL-cases. The lack of agreement on items of the medical history suggests that a Delphi study can help us reach a consensus on the essential items of clinically relevant SPTD. LEVEL OF EVIDENCE: Level V.

Cervical spine trauma - Evaluating the diagnostic power of CT, MRI, X-Ray and LODOX.

BACKGROUND: Traumatic cervical spine (c-spine) injuries account for 10% of all spinal injuries. The c-spine is prone to injury by blunt acceleration/deceleration traumas. The Canadian C-Spine rule and NEXUS criteria guide clinical decision-making but lack consensus on imaging modality when necessary. This study aims to evaluate the sensitivity and specificity of CT, MRI, X-Ray, and, for the first time, LODOX-Statscan in identifying c-spine injuries in patients with blunt trauma and neck pain. METHODS: We conducted a retrospective monocenter cohort study using patient data from the emergency department at Inselspital, Bern, Switzerland's largest level one trauma center. We identified patients presenting with trauma and neck pain during the recruitment period from 01.01.2012 to 31.12.2017. We included all patients that required a radiographic c-spine evaluation according to the NEXUS criteria. Certified spine surgeons reviewed each case, analyzed patient demographics, injury classification, trauma mechanism, and emergency management. The retrospective full case review was established as gold standard to decide whether the c-spine was injured. Sensitivity and specificity were calculated for CT, MRI, LODOX, and X-Ray imaging methods. RESULTS: We identified 4996 patients, of which 2321 met the inclusion criteria. 91.3% (n = 2120) patients received a CT scan, 8.9% (n = 206) a MRI, 9.3% (n = 215) an X-ray, and 21.5% (n = 498) a LODOX scan. By retrospective case review, 186 participants were classified as injured. The sensitivity of CT was 88.6% (specificity 99%), and 89.8% (specificity 99.2%) with orthopedic surgeon consultation. MRI had a sensitivity of 88.5% (specificity of 96.9%); highlighting 14 cases correctly diagnosed as injured by MRI and misdiagnosed by CT. Projection radiography (36.4% sensitivity, 95.1% specificity) and LODOX (5.3% sensitivity, 100% specificity) were unsuitable for ruling out spinal injury. CONCLUSION: While CT offers high sensitivity for detecting traumatic c-spine injury, MRI holds clinical significance in revealing injuries not recognized by CT in symptomatic patients. LODOX and projection radiography are insufficient for accurately ruling out c-spine injury. For patients with neurological symptoms, we recommend extended MRI use when CT scans are negative.

Health professionals' perspective on the applicability of AO Spine PROST (patient reported outcome Spine trauma) in people with a motor-complete traumatic or non-traumatic spinal cord injury.

PURPOSE: The AO Spine PROST (Patient Reported Outcome Spine Trauma) was developed for people with spine trauma and minor or no neurological impairment. The purpose is to investigate health professionals' perspective on the applicability of the AO Spine PROST for people with motor-complete traumatic or non-traumatic spinal cord injury (SCI), using a discussion meeting and international survey study. METHODS: A discussion meeting with SCI rehabilitation physicians in the Netherlands was performed, followed by a worldwide online survey among the AO Spine International community, involved in the care of people with SCI. Participants rated the comprehensibility, relevance, acceptability, feasibility and completeness of the AO Spine PROST on a 1-5 point scale (5 most positive). Comments could be provided per question. RESULTS: The discussion meeting was attended by 13 SCI rehabilitation physicians. The survey was completed by 196 participants. Comprehensibility (mean ± SD: 4.1 ± 0.8), acceptability (4.0 ± 0.8), relevance (3.9 ± 0.8), completeness (3.9 ± 0.8), and feasibility (4.1 ± 0.7) of the AO Spine PROST were rated positively for use in people with motor-complete traumatic or non-traumatic SCI. Only a few participants questioned the relevance of items on the lower extremities (e.g., walking) or missed items on pulmonary functioning and complications. Some recommendations were made for improvement in instructions, terminology and examples of the tool. CONCLUSION: Health professionals found the AO Spine PROST generally applicable for people with motor-complete traumatic or non-traumatic SCI. This study provides further evidence for the use of the AO Spine PROST in spine trauma care, rehabilitation and research, as well as suggestions for its further development.

Validation of the Hierarchical Nature of the AO Spine Sacral Classification and the Development of the Sacral AO Spine Injury Score.

STUDY DESIGN: Global cross-sectional survey. OBJECTIVE: The objective of this study was to validate the hierarchical nature of the AO Spine Sacral Classification System and develop an injury scoring system. SUMMARY OF BACKGROUND DATA: Although substantial interobserver and intraobserver reliability of the AO Spine Sacral Classification System has been established, the hierarchical nature of the classification has yet to be validated. METHODS: Respondents numerically graded each variable within the classification system for severity. Based on the results, a Sacral AO Spine Injury Score (AOSIS) was developed. RESULTS: A total of 142 responses were received. The classification exhibited a hierarchical Injury Severity Score (ISS) progression (A1: 8 to C3: 95) with few exceptions. Subtypes B1 and B2 fractures showed no significant difference in ISS (B1 43.9 vs. B2 43.4, P =0.362). In addition, the transitions A3→B1 and B3→C0 represent significant decreases in ISS (A3 66.3 vs. B1 43.9, P <0.001; B3 64.2 vs. C0 46.4, P <0.001). Accordingly, A1 injury was assigned a score of 0. A2 and A3 received scores of 1 and 3 points, respectively. Posterior pelvic injuries B1 and B2 both received a score of 2. B3 received a score of 3 points. C0, C1, C2, and C3 received scores of 2, 3, 5, and 6 points, respectively. The scores assigned to neurological modifiers N0, N1, N2, N3, and NX were 0, 1, 2, 4, and 3, respectively. Case-specific modifiers M1, M2, M3, and M4 received scores of 0, 0, 1, and 2 points, respectively. CONCLUSIONS: The results of this study validate the hierarchical nature of the AO Spine Sacral Classification System. The Sacral AOSIS sets the foundation for further studies to develop a universally accepted treatment algorithm for the treatment of complex sacral injuries. LEVEL OF EVIDENCE: Level IV-Diagnostic.

Reliability and Validity of the German Version of the AO Spine Patient Reported Outcome Spine Trauma Questionnaire.

STUDY DESIGN: A single-center validation study. OBJECTIVE: To translate and cross-culturally adapt the AO Spine PROST (Patient Reported Outcome Spine Trauma) into German, and to test its psychometric properties among German-speaking Swiss spine trauma patients. METHODS: Patients were recruited from a level-1 Swiss trauma center. Next to the AO Spine PROST, the EQ-5D-3L questionnaire was used for concurrent validity. Questionnaires were filled out at two-time points for test-retest reliability. Patient characteristics were analyzed using descriptive statistics. For content validity, floor, and ceiling effects, as well as any irrelevant and missing questions were analyzed. Construct validity of the AO Spine PROST questionnaire to the EQ-5D-3L was tested using Spearman correlation tests. RESULTS: The AOSpine PROST was translated and adapted into German using established guidelines. We included 179 patients. The floor effect for all items was well within the optimal range (below 15%), while the ceiling effect of seven items was within the optimal range. None of the items displayed a problematic floor or ceiling effect. The overall test-retest reliability of the total PROST score was excellent, with an ICC of .83 (95% CI .69-.91). The Spearman correlation coefficient between the total PROST summary score and EQ-5D-3 L was ρ = .63. CONCLUSIONS: The German version of the AO Spine PROST questionnaire demonstrated very good validity and reliability results.

Anterior thoracolumbar column reconstruction with the vertebral body stent-safety and efficacy.

PURPOSE: The aim of this study was to assess safety and efficacy of vertebral body stenting (VBS) by analyzing (1) radiographic outcome, (2) clinical outcome, and (3) perioperative complications in patients with vertebral compression fractures treated with VBS at minimum 6-month follow-up. METHODS: In this retrospective cohort study, 78 patients (61 ± 14 [21-90] years; 67% female) who have received a vertebral body stent due to a traumatic, osteoporotic or metastatic thoracolumbar compression fracture at our hospital between 2012 and 2020 were included. Median follow-up was 0.9 years with a minimum follow-up of 6 months. Radiographic and clinical outcome was analyzed directly, 6 weeks, 12 weeks, 6 months postoperatively, and at last follow-up. RESULTS: Anterior vertebral body height of all patients improved significantly by mean 6.2 ± 4.8 mm directly postoperatively (p < 0.0001) and remained at 4.3 ± 5.1 mm at last follow-up compared to preoperatively (p < 0.0001). The fracture kyphosis angle of all patients improved significantly by mean 5.8 ± 6.9 degrees directly postoperatively (p < 0.0001) and remained at mean 4.9 ± 6.9 degrees at last follow-up compared to preoperatively (p < 0.0001). The segmental kyphosis angle of all patients improved significantly by mean 7.1 ± 7.6 degrees directly postoperatively (p < 0.0001) and remained at mean 2.8 ± 7.8 degrees at last follow-up compared to preoperatively (p = 0.03). Back pain was ameliorated from a preoperative median Numeric Rating Scale value of 6.5 to 3.0 directly postoperatively and further bettered to 1.0 six months postoperatively (p = 0.0001). Revision surgery was required in one patient after 0.4 years. CONCLUSION: Vertebral body stenting is a safe and effective treatment option for osteoporotic, traumatic and metastatic compression fractures.

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.

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.

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.

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 (< 5 years, 5-10 years, 10-20 years, and > 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 (< 5 years: 0.74 vs 5-10 years: 0.69 vs 10-20 years: 0.69 vs > 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 (< 5 years: 0.67 vs 5-10 years: 0.62 vs 10-20 years: 0.61 vs > 20 years: 0.62), and only surgeons with > 20 years of experience did not have substantial reliability on assessment 2 (< 5 years: 0.62 vs 5-10 years: 0.61 vs 10-20 years: 0.61 vs > 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.