Subaxial Injury Classification Research Articles

Adverse events after surgery for injuries to the subaxial cervical spine: analysis of incidence and risk factors.

To determine the incidence of severe surgical adverse events (sSAE) after surgery of patients with subaxial cervical spine injury (sCS-Fx) and to identify patient, treatment, and injury-related risk factors. Retrospective analysis of clinical and radiological data of sCS-Fx patients treated surgically between 2010 and 2020 at a single national trauma center. Baseline characteristics of demographic data, preexisting conditions, treatment, and injury morphology were extracted. Incidences of sSAEs within 60 days after surgery were analyzed. Univariate analysis and binary logistic regression for the occurrence of one or more sSAEs were performed to identify risk factors. P-values < .05 were considered statistically significant. Two hundred and ninety-two patients were included. At least one sSAE occurred in 49 patients (16.8%). Most frequent were sSAEs of the surgical site (wound healing disorder, infection, etc.) affecting 29 patients (9.9%). Independent potential risk factors in logistic regression were higher age (OR 1.02 [1.003-1.04], p = .022), the presence of one or more modifiers in the AO Spine Subaxial Injury Classification (OR 2.02 [1.03-3.96], p = .041), and potentially unstable or unstable facet injury (OR 2.49 [1.24-4.99], p = .010). Other suspected risk factors were not statistically significant, among these Injury Severity Score, the need for surgery for concomitant injuries, the primary injury type according to AO Spine, and preexisting medical conditions. sSAE rates after treatment of sCS-Fx are high. The identified risk factors are not perioperatively modifiable, but their knowledge should guide intra and postoperative care and surgical technique.

Comparison of Anterior Cervical Discectomy Fusion Combined with Lateral Mass Screw and with Cervical Pedicle Screw Fixation Surgery under O-Arm Navigation for Single-Stage Management of Severe Lower Cervical Fracture Dislocation.

The incidence of severe lower cervical fractures and dislocations due to trauma has increased significantly, and the optimal treatment remains controversial. This study compares the safety and efficacy of anterior cervical discectomy fusion (ACDF) combined with lateral mass screw (LMS) and with cervical pedicle screw (CPS) fixation surgery under O-arm navigation as single-stage treatments of severe lower cervical fracture dislocations. Data from 48 patients who underwent ACDF + CPS (Group A) or ACDF + LMS (Group B) for severe lower cervical fracture dislocation between January 2016 and September 2020 were retrospectively reviewed. Groups A and B comprised 25 and 23 cases, respectively. Clinical parameters, such as operative time, intraoperative blood loss, number of fixed segments, posterior incision length, operative complications, and hospitalization days were recorded. Preoperatively and postoperatively, the sub-axial injury classification (SLIC) score, the American Spinal Injury Association (ASIA) impairment scale, and the Japanese Orthopaedic Association (JOA) score were recorded and analyzed using Student's t-test. The SLIC scores were 7.1 ± 1.2 and 7.5 ± 1.1, ASIA were 1.5 ± 0.6 and 1.2 ± 0.6, JOA score improvements were 3.2 ± 2.4 and 3.0 ± 2.1, operative times were 282.1 ± 91.7 and 266.5 ± 88.2 min, intraoperative blood losses were 437.8 ± 118.5 and 418.7 ± 104.2 mL, fixed segments were 2.8 ± 0.7 and 4.8 ± 1.1, and lengths of posterior incisions were 12.7 ± 2.8 and 13.8 ± 3.2 cm in Groups A and B, respectively. There was no significant difference between the two groups in the operative time, intraoperative blood loss, incision length, and postoperative recovery; however, group A had more fixed segments. At the final follow-up, no intraoperative or postoperative complications directly caused by the implant were present. Throughout the follow-up, all cases showed recovery and progressive improvement. Both ACDF + LMS and ACDF + CPS under O-arm navigation can safely and effectively restore cervical vertebral sequence, fully release spinal canal compression, and promote patients' neurological recovery. Thus, both are effective treatments for severe lower cervical fracture dislocations. However, compared to LMS, CPS under O-arm navigation has shorter fixed segments and induces less trauma.

An international validation of the AO spine subaxial injury classification system

PurposeTo validate the AO Spine Subaxial Injury Classification System with participants of various experience levels, subspecialties, and geographic regions.MethodsA 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.ResultsA 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).ConclusionThe 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.

O-Arm Navigated Cervical Pedicle Screw Fixation in the Treatment of Lower Cervical Fracture-Dislocation.

ObjectiveTo evaluate the safety and efficacy of cervical pedicle screw (CPS) placement with O‐arm navigation in the treatment of lower cervical fracture‐dislocation.MethodsA retrospective clinical study was performed involving 42 consecutive patients with lower cervical spine fracture‐dislocation who underwent CPS fixation surgery with O‐arm navigation (CPS group) or received conventional lateral mass screw (LMS) fixation surgery (LMS group) between August 2015 and August 2019. Accuracy of CPS position was evaluated by postoperative CT. The clinical parameters including preoperative and final follow‐up Japanese Orthopaedic Association (JOA) score and American Spinal Injury Association (ASIA) Impairment Scale, preoperative Sub‐axial Injury Classification (SLIC) score, number of fixation segments, operation time, intraoperative blood loss, injury mechanism, injury location, surgical complications were also assessed between the two groups.ResultsIn LMS group, the preoperative SLIC score was 7.5 ± 0.9, ASIA score improvement was 0.8 ± 0.5, JOA score improvement was 3.0 ± 1.8, mean operation time was 204 ± 89 min, intraoperative blood loss was 311 ± 127 ml. In CPS group, the preoperative SLIC score was 7.3 ± 1.2, ASIA score improvement was 0.9 ± 0.5, JOA score improvement was 3.2 ± 2.4, mean operation time is 241 ± 85 min, intraoperative blood loss is about 327 ± 120 ml. There was no significant difference in terms of above clinical parameters between the two groups (P > 0.05), the fixation segments in CPS group (3.5 ± 1.1) were less than that in LMS group (4.2 ± 0.7) (P = 0.037). The accuracy of CPS insertion was evaluated based on postoperative CT. Of all the 118 CPSs, 83 (70.3%) were defined as Grade 0; 27 (22.9%) as Grade 1; eight (6.8%) as Grade 2; and none as Grade 3. CPS malposition rate in this study was 6.8%. In this study, there was no direct intraoperative or postoperative complication caused by CPS or LMS insertion. All the operations were successfully completed in two groups. One of the patients in LMS group presented cerebrospinal fluid leak caused by bone fragment broken of the dural sac, which led to delayed incision healing. CPS group and LMS group both had two patients who suffered pulmonary infection after surgery. A total of 78.6% of the patients showed evidence of neurologic recovery. Satisfactory reduction was achieved in all cases and maintained throughout the follow‐up duration.ConclusionIn the treatment of lower cervical spine fracture‐dislocation, cervical pedicle screw insertion with O‐arm navigation is a safe and effective method for posterior fixation.

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

Global cross-sectional survey. To develop and refine the techniques for web-based international validation of fracture classification systems. 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. 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). 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.

Variations in management of A3 and A4 cervical spine fractures as designated by the AO Spine Subaxial Injury Classification System.

Optimal management of A3 and A4 cervical spine fractures, as defined by the AO Spine Subaxial Injury Classification System, remains controversial. The objectives of this study were to determine whether significant management variations exist with respect to 1) fracture location across the upper, middle, and lower subaxial cervical spine and 2) geographic region, experience, or specialty. A survey was internationally distributed to 272 AO Spine members across six geographic regions (North America, South America, Europe, Africa, Asia, and the Middle East). Participants' management of A3 and A4 subaxial cervical fractures across cervical regions was assessed in four clinical scenarios. Key characteristics considered in the vignettes included degree of neurological deficit, pain severity, cervical spine stability, presence of comorbidities, and fitness for surgery. Respondents were also directly asked about their preferences for operative management and misalignment acceptance across the subaxial cervical spine. In total, 155 (57.0%) participants completed the survey. Pooled analysis demonstrated that surgeons were more likely to offer operative intervention for both A3 (p < 0.001) and A4 (p < 0.001) fractures located at the cervicothoracic junction compared with fractures at the upper or middle subaxial cervical regions. There were no significant variations in management for junctional incomplete (p = 0.116) or complete (p = 0.342) burst fractures between geographic regions. Surgeons with more than 10 years of experience were more likely to operatively manage A3 (p < 0.001) and A4 (p < 0.001) fractures than their younger counterparts. Neurosurgeons were more likely to offer surgical stabilization of A3 (p < 0.001) and A4 (p < 0.001) fractures than their orthopedic colleagues. Clinicians from both specialties agreed regarding their preference for fixation of lower junctional A3 (p = 0.866) and A4 (p = 0.368) fractures. Overall, surgical fixation was recommended more often for A4 than A3 fractures in all four scenarios (p < 0.001). The subaxial cervical spine should not be considered a single unified entity. Both A3 and A4 fracture subtypes were more likely to be surgically managed at the cervicothoracic junction than the upper or middle subaxial cervical regions. The authors also determined that treatment strategies for A3 and A4 subaxial cervical spine fractures varied significantly, with the latter demonstrating a greater likelihood of operative management. These findings should be reflected in future subaxial cervical spine trauma algorithms.

Variation in global treatment for subaxial cervical spine isolated unilateral facet fractures

PurposeTo determine the variation in the global treatment practices for subaxial unilateral cervical spine facet fractures based on surgeon experience, practice setting, and surgical subspecialty.MethodsA survey was sent to 272 members of the AO Spine Subaxial Injury Classification System Validation Group worldwide. Questions surveyed surgeon preferences with regard to diagnostic work-up and treatment of fracture types F1–F3, according to the AO Spine Subaxial Cervical Spine Injury Classification System, with various associated neurologic injuries.ResultsA total of 161 responses were received. Academic surgeons use the facet portion of the AO Spine classification system less frequently (61.6%) compared to hospital-employed and private practice surgeons (81.1% and 81.8%, respectively) (p = 0.029). The overall consensus was in favor of operative treatment for any facet fracture with radicular symptoms (N2) and for any fractures categorized as F2N2 and above. For F3N0 fractures, significantly less surgeons from Africa/Asia/Middle East (49%) and Europe (59.2%) chose operative treatment than from North/Latin/South America (74.1%) (p = 0.025). For F3N1 fractures, significantly less surgeons from Africa/Asia/Middle East (52%) and Europe (63.3%) recommended operative treatment than from North/Latin/South America (84.5%) (p = 0.001). More than 95% of surgeons included CT in their work-up of facet fractures, regardless of the type. No statistically significant differences were seen in the need for MRI to decide treatment.ConclusionConsiderable agreement exists between surgeon preferences with regard to unilateral facet fracture management with few exceptions. F2N2 fracture subtypes and subtypes with radiculopathy (N2) appear to be the threshold for operative treatment.

The classifications of subaxial cervical spine traumatic injuries. Part 4. AOSpine Subaxial Classification System

Cervical spine injuries are a fairly common consequence of mechanical impact on the human body. The subaxial level of the cervical spine accounts for approximately half to 2/3 of these injuries. Despite the numerous classification systems that exist for describing these injuries, the recommendations for treatment strategy are very limited, and currently none of them is universal and generally accepted. Consequently, treatment decisions are based on the individual experience of the specialist, but not on evidence or algorithms. While the classification system based on the mechanism of trauma originally proposed by B.L. Allen et al. and subsequently modified by J.H. Harris Jr et al., was comprehensive, but lacked evidence, which to some extent limited its clinical applicability. Similarly, the Subaxial Injury Classification System proposed by the Spine Trauma Group, had no distinct and clinically significant patterns of morphological damage. This fact hindered the standardization and unification of tactical approaches. As an attempt to solve this problem, in 2016 Alexander Vaccaro, together with AO Spine, proposed the AO Spine subaxial cervical spine injury classification system, using the principle of already existing AOSpine classification of thoracolumbar injuries. The aim of the project was to develop an effective system that provides clear, clinically relevant morphological descriptions of trauma patterns, which should contribute to the determination of treatment strategy. The proposed classification of cervical spine injuries at the subaxial level follows the same hierarchical approach as previous AO classifications, namely, it characterizes injuries based on 4 parameters: (1) injury morphology, (2) facet damage, (3) neurological status, and (4) specific modifiers. The morphology of injuries is divided into 3 subgroups of injuries: A (compression), B (flexion-distraction), and C (dislocations and displacements). Damage types A and B are divided into 5 (A0-A4) and 3 (B1-B3) subtypes, respectively. When describing damage of the facet joints, 4 subtypes are distinguished: F1 (fracture without displacement), F2 (unstable fracture), F3 (floating lateral mass) and F4 (dislocation). The system also integrates the assessment of neurological status, which is divided into 6 subtype). In addition, the classification includes 4 specific modifiers designed to better detail a number of pathological conditions. The performance evaluation of AOSpine SCICS showed a moderate to significant range of consistency and reproducibility. Currently, a quantitative scale for assessing the severity of classification classes has been proposed, which also, to a certain extent, contributes to decision-making regarding treatment strategy.

Management of subaxial cervical spine trauma: Clinical results of early surgical decompression

Traumatic injuries of the subaxial cervical spine (C3-7); considered among the most common and most damaging injuries to the axial skeleton. Decompression of the spine is standard approach after cervical spinal cord injury.In this study, 72 patients who underwent early decompression with the decision of surgery according to the classification system with the Subaxial Injury Classification and Severity Scale (SLICS) among 212 patients who developed spine fractures as a result of acute traumatic subaxial cervical trauma were examined.ASIA scoring system was used for neurological examination evaluation.Patients were included in the rehabilitation program, which lasted at least six months after the operation.Neurological recovery results were evaluated with ASIA scores obtained after the rehabilitation program.It has been shown that early surgery for subaxial cervical spine fractures contributes significantly to the patient's neurological recovery.

The classifications of subaxial cervical spine traumatic injuries. Part 2. The Subaxial Injury Classification and Severity Scale (SLIC)

Cervical spine trauma remains one of the most severe musculoskeletal injuries with high mortality and disability. The majority of injuries of this location occur at the subaxial level — more than 65 % of fractures and 75 % of dislocations. The complex anatomical structure of the cervical spine, its high mobility, the multiplicity of injury variants, as well as the potentially catastrophic consequences of incorrect therapy, determine correct tactics to be a difficult clinical task, even for specialists with extensive practical experience. Despite the impressive amount of scientific research and clinical achievements, the classification and approaches to treating fractures and dislocations of the cervical spine remain quite controversial.This review describes one of the first clinical classifications of traumatic injuries of the cervical spine at the subaxial level. The Subaxial Injury Classification and Severity Scale were developed by spinal injury study group in 2007, and currently, it is one of the most common, simple, clinically-oriented tools for unifying damage and treatment tactics. One of the indisputable advantages of the presented systematization is the point-based assessment of the injury severity, a sufficiently developed therapeutic and tactical algorithm and a significant evidence base.The classification considers three main groups of criteria that are fundamental in making clinical decisions regarding the management of patients with traumatic injury: the morphology of injury; integrity of the disco-ligamentous complex; neurological status.The article provides a detailed analysis of principles of classification cases construction, as well as the main surgical approaches, depending on the nature and extent of damage to various anatomical structures. Even though the described tactical principles are certainly purely recommendatory, nevertheless, therapy based on the specified scale is highly clinically argued.

CURRENTLY AVAILABLE CLASSIFICATION SYSTEMS FOR LOWER CERVICAL SPINE INJURIES. PART 2. SYSTEMATIC REVIEW OF STUDIES ON THE RELIABILITY AND REPRODUCIBILITY OF EXISTING SCALES

The study objective is to review the Russian and foreign studies and to identify an optimal classification system for lower cervical spine injuries. Materials and methods. This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We conducted a search for articles published in English (PubMed database) and Russian (eLIBRARY.ru). The inclusion criteria were as follows: available full text, patient age ≥18 years, and information on one of the validation phases for classifications according to L. Audige et al. Results. A total of 30 articles were eligible. Of them, 3 studies were published in Russian (by one group of authors); however, they didn’t contain required statistical parameters and had duplicated data; therefore, they were excluded from the analysis. Out of 27 articles published in English, 8 articles met all the criteria and were included into the systematic review. The AOSpine and Subaxial Injury Classification Systems demonstrated the highest reliability and reproducibility of the results. The Allen–Fergusson classification has lower intraobserver and interobserver agreement coefficients, but it can give a clearer visual representation of injuries. We also assessed J. Harris classification system. The reliability of the scale developed by С. Argenson et al. was not evaluated. The analyzed publications contained no data for full evaluation of the Cervical Spine Injury Severity Score. Our analysis clearly demonstrated the need for a more thorough evaluation of all available scales and classifications. This study should be multicenter and involve experts with different levels of experience (from residents to experienced spinal surgeons). Moreover, it should analyze not only the reproducibility of individual classifications, but also the aspects of learning and the relationship between individual scales and systems. The main study limitations included insufficient number of publications, small sample sizes, heterogeneity of groups, and differences in the experience of experts. Conclusion. The AOSpine and Subaxial Injury Classification Systems are the most reliable classification systems. However, the data available in literature is not sufficient for a full comparison of all existing scales and systems. Further multicenter studies on the reliability of classifications are needed to select an optimal one.

Currently available classification systems for lower cervical spine injuries. Part 1. Overview of the most popular scales and classifications

This article provides a detailed illustrated description of currently available classification and scoring systems for lower cervical spine injuries (including Allen–Fergusson, J. Harris et al., C. Argenson et al., and AOSpine classifications, Subaxial Injury Classification System and Cervical Spine Injury Severity Score). The present review primarily aims to discuss the advantages and disadvantages of each classification system.

Surgical Treatment of Lower Cervical Locked Facet. An Experience in 20 Cases

Background: Cervical spine injuries are common as a result of a growing number of high energy accidents. The subaxial Injury Classification System and Severity Score (SLICS) suggest that a unilateral or bilateral facet dislocation must be managed surgically, even in the absence of SCI (Level of Evidence III). The surgical approaches could be anterior, posterior or combined anterior and posterior approaches. Methods: 20 patients, 12 males and 8 females, with age ranged from 20 to 45 years with lower cervical spine locked facet treated operatively by anterior or posterior spinal instrumentation after trial of closed reduction by skull traction. Results: In this series, satisfactory closed reduction was achieved in 15 patients with percentage 75% and fixed anteriorly, but 5 patients with percentage 25% needed posterior approach for reduction. Regarding ASIA score all of the patients improved at least one level after surgery except 2 cases with preoperative score A: they didn’t improve. Mean preoperative pain score VAS was 7.7 (range from 5 to 9) and postoperative mean of VAS was 0.75 with range from 0 to 3 until final follow up. Conclusion: Anterior approach with discectomy and fusion is necessary; however, if the closed reduction failed, posterior open reduction is indicated with lateral mass fixation, combined approaches can be indicated in specific cases such as increase of the kyphotic angle post anterior approach or when an osteotomy may be required to restore cervical alignment and neural decompression.

Predictors of Failure of Nonoperative Management Following Subaxial Spine Trauma and Creation of Modified Subaxial Injury Classification System

Subaxial cervical spine injuries may be treated with either nonoperative stabilization or surgical fixation. The subaxial injury classification (SLIC) provides 1 method for suggesting the degree of necessity for surgery. In the current study, we examined if the SLIC score, or other preoperative metrics, can predict failure of nonoperative management. We performed a retrospective chart review to identify patients who presented with acute, nonpenetrating, subaxial cervical spine injury within our health system between 2007 and 2016. Patient demographics, medical comorbidities, injuries, and treatments were collected. Logistic regression analysis was used to determine potential predictors of failure of nonoperative management. During the study period, 40 patients met the inclusion criteria. A small subset of patients failed nonoperative management (n= 5, 12.5%). The mean SLIC score was 3.9 ± 1.9; however, 14 (35%) patients had scores >4. Neither total SLIC score (P= 0.68) nor SLIC subscores (morphology [P= 0.96], discoligamentous complex [P= 0.83], neurologic status [P= 0.60]) predicted failure of nonoperative treatment. Time to evaluation/treatment did predict failure of nonoperative management. Evaluation within 8 hours of injury was a negative predictor of failure (odds ratio= 0.03, P= 0.001) and evaluation 24 hours or more after injury was a positive predictor of failure (odds ratio= 66.00, P < 0.001). We created a modified SLIC score on the basis of these findings, which significantly predicted failure of nonoperative management (P= 0.044). Management of subaxial spine injuries is complex. In our cohort, SLIC scoring did not adequately predict odds of failure of nonoperative management. Time to evaluation, however, did. We created a modified SLIC score that significantly predicted failure of nonoperative management.

Functional Outcomes of Subaxial Spine Injuries Managed With 2-Level Anterior Cervical Corpectomy and Fusion: A Prospective Study

ObjectiveTo evaluate the results of operative management of subaxial spine injuries managed with 2-level anterior cervical corpectomy and fusion with a cervical locking plate and autologous bone–filled titanium mesh cage. MethodsThis study included 23 patients with a subaxial spine injury who matched the inclusion criteria, underwent 2-level anterior cervical corpectomy and fusion at our institution between 2013 and 2016, and were followed up for neurological recovery, axial pain, fusion, pseudarthrosis, and implant failure. ResultsAccording to Allen and Ferguson classification, there were 9 cases of distractive extension; 4 of compressive extension; 3 each of compressive flexion, vertical compression, and distractive flexion; and 1 of lateral flexion. Sixteen patients had a score of 6 on the Subaxial Injury Classification system, and the rest had a score of more than 6. The mean follow-up period was 19 months (range, 12–48 months). Neurological recovery was observed in most of the patients (78.21%). All patients experienced relief of axial pain. None of the patients received a blood transfusion. Twenty-one patients (91.3%) showed solid fusion and 2 (8.69%) showed possible pseudarthrosis, with no complications related to the cage or plate. ConclusionTwo-level anterior cervical corpectomy and fusion, along with stabilization with a cervical locking plate and autologous bone graft-filled titanium mesh cage, can be considered a feasible and safe method for treating specific subaxial spine injuries, with the benefits of high primary stability, anatomical reduction, and direct decompression of the spinal cord.

Reliability of Allen Ferguson classification versus subaxial injury classification and severity scale for subaxial cervical spine injuries: a psychometrics study

A psychometrics study. To determine intra and inter-observer reliability of Allen Ferguson system (AF) and sub-axial injury classification and severity scale (SLIC), two sub axial cervical spine injury (SACI) classification systems. Online multi-national study METHODS: Clinico-radiological data of 34 random patients with traumatic SACI were distributed as power point presentations to 13 spine surgeons of the Spine Trauma Study Group of ISCoS from seven different institutions. They were advised to classify patients using AF and SLIC systems. A reference guide of the two systems had been mailed to them earlier. After 6 weeks, the same cases were re-presented to them in a different order for classification using both systems. Intra and inter-observer reliability scores were calculated and analysed with Fleiss Kappa coefficient (k value) for both the systems and Intraclass correlation coefficient(ICC) for the SLIC. Allen Ferguson system displayed a uniformly moderate inter and intra-observer reliability. SLIC showed slight to fair inter-observer reliability and fair to substantial intra-observer reliability. AF mechanistic types showed better inter-observer reliability than the SLIC morphological types. Within SLIC, the total SLIC had the least inter-observer agreement and the SLIC neurology had the highest intra-observer agreement. This first external reliability study shows a better reliability for AF as compared to SLIC system. Among the SLIC variables, the DLC status and the total SLIC had least agreement. Low-reliability highlights the need for improving the existing classification systems or coming out with newer ones that consider limitations of the existing ones.

One-stage anterior-posterior decompression and internal fixation for severe fracture-dislocation of lower cervical spine in "beach chair position"

Objective To explore the surgical feasibility and clinical efficacy of one-stage anterior-posterior approaches in treatment of severe fracture and dislocation of lower cervical spine in beach chair . Methods Sixteen male cases of severe fracture and dislocation of lower cervical spine and with a mean age of 49.8 years (range, 36-78 years) treated surgically from May 2012 to May 2016 were analyzed retrospectively by using case series study. The segment of injury was C4-5 in 4 cases, C5-6 in 7 and C6-7 in 5. The degree of spinal cord injury according to the American Spine injury Association (ASIA) score was Grade A in 4 cases, Grade B in 7 and Grade C in 5. Sub-axial injury classification (SLIC) score was 8 points in 9 cases and 9 points in 7. After a general anesthesia, a ring with a hole was hanged on patient's head before the operation. Then, under the protection of hole traction, the upper of operating bed was swung up slowly, so that the patient was restricted in vertical beach chair with traction on the halo in order to immobilize the head and partially reduce the kyphotic deformity. Routine cervical anterior-posterior approach was done with the exposure of damaged section of the front and rear structure. Pedicle screw system or lateral mass screw displacement was conducted. Anterior intervertebral discectomy or fracture vertebral was performed, using collaborative reset prying method before and after the road. In the front of intervertebral cage or titanium net support bone graft, rear pedicle screws or lateral mass screws fixation and bone graft fusion were implemented. The operation time and blood loss were recorded. The healing of the wound was observed. The recovery of neurological function was evaluated according to the ASIA grade. Postoperative review X-ray, CT and MRI were done to evaluate the reset and bone graft in position and fusion. Results All the surgeries were done well without aeroembolism and other related complications. The mean operative time was 153 minutes (range, 150-180 minutes), and the mean amount of blood loss was 543 ml (range, 400-800 ml). Sixteen cases were followed-up from 6 to 24 months (mean 13.7 months). All the incision were healed at I stage. Spinal cord function did not aggravate. The ASIA grade was improved with an average of one to two Grades 6 months after surgery. Postoperative X-ray and CT confirmed that graft object position was favorable and cervical sequence was recovered well. The Cobb angle decreased from (23.6±5.3)°preoperatively to (4.0±0.4)°postoperatively, and the translational displacement of vertebral body was restored into (2.7±0.4)mm (P<0.01) from (10.9±1.6)mm before operation. The cervical spinal canal was not obstructed and the cervical spinal cord was relieved, showed by MRI. Conclusions One-stage anterior-posterior approaches for severe fracture and dislocation of lower cervical spine circumferential reconstruction in beach chair is a beneficial and effective method, without the need of changing positions in a collaborative reduction and fixation. The method can reduce the interference of spinal cord, shorten the operation time and save anterior extra fixation. Key words: Cervical vertebrae; Spinal fractures; Dislocation; Beach chair position

Treatment of odontoid fracture combined with lower cervical spinal cord injuries without fracture or dislocation

To discuss the clinical characteristics, mechanism, and treatment of odontoid fracture combined with lower cervical spinal cord injuries without fracture or dislocation. According to the inclusion and exclusion criteria, 7 male patients aged 37-71 years (mean, 51.4 years), suffered from odontoid fractures combined with lower cervical spinal cord injuries without fracture or dislocation were analyzed retrospectively between June 2007 and October 2015. The trauma causes were traffic accidents in 2 cases, fall in 2 cases, and hit injury in 3 cases. The time from injury to admission was 2 hours to 3 days with an average of 9 hours. According to Anderson-Grauer classification of odontoid fracture, 1 case of type IIA, 3 cases of type IIB, 2 cases of type IIC, and 1 case of shallow type III were found. The cervical spinal cord injuries affected segments included C 4, 5 in 1 case, C 4-6 in 2 cases, and C 5-7 in 4 cases. All the cervical spine had different degenerative changes: 2 of mild, 3 of moderate, and 2 of severe. The lower cervical spinal cord injury was assessed by Sub-axial Injury Classification (SLIC) with scoring of 4-6 (mean, 5.1). The visual analogue scale (VAS) score was used to evaluate the occipital neck pain with scoring of 7.8±1.0; the neurological function was assessed by American Spinal Injury Association (ASIA) as grade B in 1 case, grade C in 4 cases, and grade D in 2 cases; and Japanese Orthopedic Association score (JOA) was 9.2±3.9. For the odontoid fractures, 4 cases were fixed with anterior screw while the others were fixed with posterior atlantoaxial fixation and fusion. For the lower cervical spine, 4 cases were carried out with anterior cervical corpectomy and titanium fusion while the others with anterior cervical disecotomy and Cage fusion. The operation time was 178-252 minutes (mean, 210.2 minutes); the intraoperative blood loss was 60-140 mL (mean, 96.5 mL) and with no blood transfusion. All incisions healed primarily. All the patients were followed up 12-66 months (mean, 18 months). There was no direct surgical related complications during operation, and all bone grafting got a fusion at 6-9 months (mean, 7.7 months) after operation. There was no inter-fixation failure or loosening. At last follow-up, the VAS score declined to 1.7±0.7 and JOA score improved to 15.1±1.7, showing significant differences when compared with preoperative ones ( t=18.064, P=0.000; t=-7.066, P=0.000). The neurological function of ASIA grade were also improved to grade D in 5 cases and grade E in 2 cases, showing significant difference ( Z=-2.530, P=0.011). Complex forces and degeneration of lower cervical spine were main reasons of odontoid fracture combined with lower cervical spinal cord injuries without fracture or dislocation. The type of odontoid fracture and neurological deficit status of lower cervical spinal cord were important to guide making strategy of one-stage operation with a satisfactory clinic outcome.

Update on subaxial cervical trauma classification systems

Injury classification systems guide management, predict prognosis, and allow for communication between providers. Several classification systems for subaxial cervical trauma have been described. Historically, classifications focused on osseous morphology, inferred mechanism of action, and stability. Later, neurologic status of the patient and integrity of the posterior ligamentous complex were described as important determinants of treatment. This article will detail important historic classifications, the Subaxial Injury Classification (SLIC) and Severity Scale, and the novel AOSpine Subaxial Cervical Spine Injury Classification System.

The Efficacy of Modified Allen Staging Classification and Subaxial Injury Classification (SLIC) Scale of Distraction-Extension Injury in Cervical Spine

The Efficacy of Modified Allen Staging Classification and Subaxial Injury Classification (SLIC) Scale of Distraction-Extension Injury in Cervical Spine