AOSpine—Spine Trauma Classification System: The Value of Modifiers: A Narrative Review With Commentary on Evolving Descriptive Principles

Study Design: Narrative review. Objectives: To describe the current AOSpine Trauma Classification system for spinal trauma and highlight the value of patient-specific modifiers for facilitating communication and nuances in treatment. Methods: The classification for spine trauma previously developed by The AOSpine Knowledge Forum is reviewed and the importance of case modifiers in this system is discussed. Results: A successful classification system facilitates communication and agreement between physicians while also determining injury severity and provides guidance on prognosis and treatment. As each injury may be unique among different patients, the importance of considering patient-specific characteristics is highlighted in this review. In the current AOSpine Trauma Classification, the spinal column is divided into 4 regions: the upper cervical spine (C0-C2), subaxial cervical spine (C3-C7), thoracolumbar spine (T1-L5), and the sacral spine (S1-S5, including coccyx). Each region is classified according to a hierarchical system with increasing levels of injury or instability and represents the morphology of the injury, neurologic status, and clinical modifiers. Specifically, these clinical modifiers are denoted starting with M followed by a number. They describe unique conditions that may change treatment approach such as the presence of significant soft tissue damage, uncertainty about posterior tension band injury, or the presence of a critical disc herniation in a cervical bilateral facet dislocation. These characteristics are described in detail for each spinal region. Conclusions: Patient-specific modifiers in the AOSpine Trauma Classification highlight unique clinical characteristics for each injury and facilitate communication and treatment between surgeons

The Sub-axial Cervical Spine Injury Classification System (SLIC): A Novel Approach to Recognize The Importance of Morphology, Neurology and Integrity of the Disco-ligamentous complex

Abstract Background Context Despite technological advances in spine surgery, classification of sub-axial cervical spine injuries remains largely descriptive, lacking standardization and any relationship to prognosis or clinical decision making. Purpose The primary purpose of this paper is to define a classification system for sub-axial cervical spine trauma that conveys information about injury pattern and severity as well as treatment considerations and prognosis. The proposed system is designed to be both comprehensive and easy to use. The secondary objective is to evaluate the classification system in the basic principles of classification construction, namely reliability and validity. Study Design/Setting Derivation of the classification was from a synthesis of the best cervical classification parameters gleaned from an exhaustive literature review and expert opinion of experienced spine surgeons. Multi-center reliability and validity study of a cervical classification system using previously collected CT, MRI, and plain film x-ray images of sub-axial cervical trauma. Methods Important clinical and radiographic variables encountered in sub-axial cervical trauma were identified by a working section of the Spine Trauma Study Group (STSG). Significant limitations of existing injury classification systems were defined and addressed within the new system. It was then introduced to the STSG and applied to 11 cervical trauma cases selected to represent a spectrum of subaxial injury. Six weeks later, the cases were randomly re-ordered and again scored using the novel classification system. Twenty surgeons completed both intervals. Inter-rater and intra-rater reliability and several forms of validity were assessed. For comparison, the reliability of both the Harris and the Ferguson & Allen systems were also evaluated. Results Each of three main categories (injury morphology; disco-ligamentous complex integrity; and neurological status) identified as integrally important to injury description, treatment, and prognosis was assigned an ordinal score range, weighted according to its perceived contribution to overall injury severity. A composite injury severity score was modeled by summing the scores from all three categories. Treatment options were assigned based upon threshold values of the severity score. Inter-rater agreement as assessed by ICC of the DLC, Morphology, and Neurological Status scores was 0.49, 0.57, and 0.87, respectively. Intra-rater agreement as assessed by ICC of the DLC, Morphology, and Neurological Status scores was 0.66, 0.75, and 0.90, respectively. Raters agreed with treatment recommendations of the algorithm in 93.3 % of cases, suggesting high construct validity. The reliability if the SLIC treatment algorithm compared favorably to the earlier classification systems of Harris and Ferguson & Allen. Conclusions The Sub-axial Injury Classification (SLIC) and Severity Scale provides a comprehensive classification system for sub-axial cervical trauma, incorporating pertinent characteristics for generating prognoses and courses of management. Early data on validity and reliability are encouraging. Further testing is necessary before introducing the SLIC score into clinical practice

Subaxial Cervical Spine Injuries: WFNS Spine Committee Recommendations

To formulate specific guidelines for the recommendation of subaxial cervical spine injuries concerning classification, management, posttraumatic locked facets and vertebral artery injury. Computerized literature was searched on PubMed and google scholar database from 2009 to 2020. For classification, keywords "Sub Axial Cervical Spine Classification," resulting in 22 articles related to subaxial cervical spine injury classification system (SLICS) system and 11 articles related to AO (Arbeitsgemeinschaft für Osteosynthesefragen, German for "Association for the Study of Internal Fixation") Spine system. The literature search yielded 210 and 78 articles on "management of subaxial cervical spine injuries" and the role of "SLICS" and "AO Spine" respectively. Keywords "management of traumatic facet locks" were searched and closed reduction, traction, approaches and techniques were studied. "Vertebral artery injury and cervical fracture" exhibited 2,328 references from the last 15 years. The objective was to identify the appropriate diagnostic tests and optimal treatment. Up-to-date information was reviewed, and statements were produced to reach a consensus in 2 separate consensus meetings of World Federation of Neurosurgical Societies (WFNS) Spine Committee. The statements were voted and reached a positive or negative consensus using Delphi method. Based on the most relevant literature, panelists in Moscow consensus meeting conducted in May 2019 drafted the statements, and after a preliminary voting session, the consensus was identified on various statements. Another meeting was conducted at Peshawar in November 2019, where in addition to previous statements, few other statements were discussed and voted. Specific recommendations were then formulated guiding classification, management, locked facets and vertebral artery injuries. This review summarizes the WFNS Spine Committee recommendations on subaxial cervical spine injuries.info:eu-repo/semantics/publishedVersio

An Investigation of Subaxial Cervical Spine Trauma and Surgical Treatment through Biomechanical Simulation and Kinematic Analysis

In vitro biomechanical investigations can help to identify changes in subaxial cervical spine (C3-C7) stability following injury, and determine the efficacy of surgical treatments through controlled joint simulation experiments and kinematic analyses. However, with the large spectrum of cervical spine trauma, a large fraction of the potential injuries have not been examined biomechanically. This includes a lack of studies investigating prevalent flexion-distraction injuries. Therefore, the overall objective of this thesis was to investigate the changes in subaxial cervical spine kinematic stability with simulated flexion-distraction injuries and current surgical instrumentation approaches using both established and novel biomechanical techniques. Three in vitro experiments were performed with a custom-designed spinal loading simulator. The first evaluated sequential disruption of the posterior ligaments with and without a simulated facet fracture (n=7). In these specimens, posterior lateral mass screw fixation provided more stability than anterior cervical discectomy and fusion with plating (ACDFP). A second study examined a unilateral facet perch injury by reproducing a flexion-distraction injury mechanism with the simulator (n=9). The resulting soft tissue damage was quantified through meticulous dissection of each specimen, which identified the most commonly injured structures across all specimens as both facet capsules, ¾ of the annulus, and ½ of the ligamentum flavum. This information was used to develop and validate a standardized injury model (SIM) in new specimens (n=10). A final study examined the ACDFP surgical factor of graft size height (bony spacer replacing the intervertebral disc to promote fusion) for the SIM and two other injuries (n=7). Results were motion and injury dependent, which suggests that both these factors must be considered in the surgical decision. Two additional investigations were completed. The first examined mathematical techniques to generate a large number of accurate finite helical axes from six-DOF rigid body tracker output to describe changes in cervical spine kinematic stability. The second explored the effect of boundary conditions and PID control settings on the ability of the current simulator design to reproduce desired loading techniques. Ultimately, it is hoped that these results, and the protocols developed for future investigations, will provide valuable biomechanical evidence for standardized treatment algorithms

Spinal injury in underbody blast

Improvised Explosive Device (IED) is common in insurgent conflict as such devices are cheap, available, and devastating. Recent literature shows that victims of these devices often have complex injuries including spinal fractures. However, spinal injuries are not described in detail, so the mechanism and effects of these injuries are not well understood. This thesis reviews the literature with respect to spinal injuries in blast and compares it to UK military victims of IED attacks with spinal fractures. In the UK population, the majority of spinal fractures are thoracolumbar and are associated with multiple other injuries. This thesis shows that, based on the patterns of injury in UK blast victims, most fractures are caused by a combination of axial loads and flexion, with the apex of the thoracic spine and the thoracolumbar junction most affected by flexion. Military vehicles incorporate features intended to reduce the effect of blast on their occupants, and a standardised test has been established to evaluate such designs. However, the simple model of the spine used for these tests lacks validity. Understanding the behaviour of the spine in blast incidents will support development of an improved injury prediction model for future vehicle design. In this thesis an in vitro study develops a model to understand the role of posture in shaping fracture patterns when the spine is loaded at the rates seen in blast, and supports the mechanistic propositions this thesis makes about the behaviour of the spine in underbody blast. The clinical outcome and functional effect of blast related spinal fractures is unknown. In a short case series, this thesis suggests that spinal fractures lead to significant pain but the effect of spinal injuries on function is unclear as these victims also have other severe injuries.Open Acces

Magnetic resonance imaging in paediatric spinal trauma – retrospective analysis of feasibility, safety, and diagnostic value in the emergency department

Paediatric spinal trauma is a relatively uncommon but challenging entity in the emergency department. Despite the algorithms aiming to exclude spinal trauma based on symptoms and physical examination, medical imaging is often needed. Since the early 20th century, conventional radiography has been the most utilised imaging modality. In recent decades, computed tomography (CT) has become a common primary method, accompanied by magnetic resonance imaging (MRI) as an additional imaging in difficult cases and spinal cord injuries. MRI is more sensitive than CT, but it is unclear if MRI yields additional clinical value compared to CT. MRI is also more expensive, time-consuming, and less available than CT. Long scanning time makes sedation or anaesthesia often mandatory with younger children. The goals of this thesis were to assess the feasibility, safety, and accuracy in emergent spinal trauma imaging of children and adolescents. We retrospectively reviewed the imaging data and medical records of the under-18-year-old patients having undergone spinal MRI at the Emergency Radiology Department of Turku University Hospital 2013–2021 because of acute trauma. MRI demonstrated all injuries requiring surgical treatment. No MRI-related adverse events were reported, and the need for anaesthesia was mainly limited to children aged five years or younger. Unless MRI demonstrated potentially unstable features in spinal injury, the clinical value of follow-up or flexion-extension imaging was low. If the concurrent brain and spine MRI was performed because of a spinal trauma but without symptoms suggesting brain injury, the brain MRI did not reveal any traumatic findings regardless of spinal MRI findings. Our results show that emergency MRI is an accurate, feasible, and safe imaging modality in paediatric spinal trauma. Spinal injury does not seem to be a risk factor for brain injury if no brain injury-related symptoms are present. Emergency MRI reduces the need for follow-up imaging, but assessing MRI's cost-effectiveness or potential superiority over CT as primary imaging requires further studies.Lasten rankavammojen päivystyksellinen kuvantaminen – takautuva tutkimus magneettikuvauksen käyttökelpoisuudesta, turvallisuudesta ja diagnostisesta merkityksestä Rankavammat ovat moniin lasten ja nuorten vammatyyppeihin verrattuna harvi-naisia. Epäilyn herättyä rankavamman luotettava poissulkeminen oireiden ja klii-nisten tutkimuslöydösten perusteella on hankalaa, joten rankavammaepäily johtaa usein kuvantamistutkimuksiin. Röntgenkuvausta on käytetty rangan tutkimisessa yli sadan vuoden ajan, mutta viimeisten parinkymmenen vuoden aikana tietokone-tomografia (TT) on yleistynyt huomattavasti. Magneettikuvausta (MK) on käytetty täydentävänä tutkimuksena ja erityisesti selkäydinvammaepäilyn yhteydessä. MK osoittaa rangan vammamuutokset herkemmin kuin TT, mutta suuremman herkkyyden merkitys ja hyöty potilaiden hoidossa on toistaiseksi epäselvä. MK on kalliimpi ja hitaampi kuin TT, ja sen saatavuus erityisesti päivystysaikaan on huonompi. Tämän väitöstutkimuksen tarkoituksena oli arvioida MK:n tarkkuutta, turvallisuutta ja toteutettavuutta lasten ja nuorten rankavammaepäilyn vuoksi tehtävänä päivystystutkimuksena. Tutkimuksessa käytiin takautuvasti läpi Turun yliopistollisen keskussairaalan päivystysradiologian yksikössä vuosina 2013–2021 rankavammaepäilyn vuoksi alle 18-vuotiaille potilaille tehtyjen magneettikuvantamisten tiedot sekä muut vammaan liittyvät potilasasiakirjamerkinnät. MK osoitti kaikki kirurgista hoitoa vaativat rankavammat, eikä kuvantamiseen liittyviä haittatapahtumia ilmennyt. Lähes kaikki yli viisivuotiaat pystyttiin kuvantamaan ilman nukutusta. Jos vammassa ei MK:n perusteella ollut huolestuttavia piirteitä, ei seurantakuvauksista ollut lisähyötyä. Lapsilla, joille tehtiin vamman vuoksi samanaikaisesti rangan ja aivojen MK mutta joilla ei ollut aivovammaan viittaavia oireita, ei magneettikuvaus paljastanut aivo-vammaa, vaikka rangassa olisikin todettu vamma. Tulostemme perusteella MK on tarkka ja turvallinen lasten rankavammaepäilyn kuvantamistutkimus. Päivystyksellinen MK vähentää seurantakuvausten tarvetta. Kustannusvaikuttavuuden arviointi kuitenkin vaatii lisätutkimusta, samoin sen selvittäminen, onko MK merkitsevästi parempi kuin TT

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

Objective: 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. Methods: 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\u27 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. Results: 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 \u3c 0.001) and A4 (p \u3c 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 \u3c 0.001) and A4 (p \u3c 0.001) fractures than their younger counterparts. Neurosurgeons were more likely to offer surgical stabilization of A3 (p \u3c 0.001) and A4 (p \u3c 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 \u3c 0.001). Conclusions: 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

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

OBJECTIVE 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. METHODS 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. RESULTS 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). CONCLUSIONS 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

Towards Understanding the Injury Mechanics and Clinical Outcomes of Traumatic Subaxial Cervical Facet Dislocation and Fracture-Dislocation

Despite potentially devastating outcomes, the injury mechanisms of traumatic subaxial cervical facet dislocation (CFD) and fracture-dislocation (CFD+Fx) are not well understood and have not been reliably produced in biomechanical testing. In particular, bilateral CFD (BFD) with concomitant facet fracture (BFD+Fx) has not been produced experimentally, possibly due to a lack of neck muscle replication. Muscle activation may impose intervertebral compression and anterior shear during injury, increasing loading of the facets and preventing isolated dislocation via intervertebral separation – such separation has been observed during inertially-produced CFD. The mechanical behaviour of the facets during these scenarios, and the effect of axial distraction on the risk of facet fracture or dislocation, have not been investigated. The aim of this thesis was to improve understanding of the epidemiology, clinical outcomes, and injury mechanisms of CFD and CFD+Fx, and to investigate the biomechanics underlying the injury. In Study 1, a large-cohort medical record and radiographic review of subaxial cervical subluxations, dislocations, and fracture-dislocations presenting at an Australian tertiary hospital over the decade to 2014 was performed. Two primary injury causations were identified: motor vehicle accidents in younger adults, and falls in the elderly. BFD frequently caused spinal cord injury (SCI) and concomitant facet fracture was common. The C6/C7 vertebral level was most commonly involved, and injury to this level most often caused SCI. In Study 2, the bilateral inferior facets of 31 isolated human cadaver subaxial cervical vertebrae (6×C3, C4, C5, and C7, 7×C6) were loaded quasi-statically in simulated supraphysiologic anterior shear and compressive-flexion directions using a materials testing machine – these motions are thought to be associated with BFD. Facet stiffness and failure load were significantly greater in the simulated compressive-flexion loading direction, and sub-failure deflection and surface strains were higher in anterior shear. Facet tip fractures occurred during anterior shear loading, while failure through the pedicles was most common in compressive-flexion. In Study 3, the effect of intervertebral axial separation on human cadaver C6 inferior facet biomechanics during non-destructive anterior shear, axial rotation, flexion, and lateral bending motions of twelve C6/C7 functional spinal units (FSUs) was investigated. Axial compression generally increased facet deflection and strains, when compared to intervertebral distraction. In Study 4, a method was developed to reliably apply 20 mm of constrained anterior shear motion with superimposed intervertebral axial compression or distraction to twelve human cadaver cervical FSUs in a materials testing machine. The effect of superimposed axial compression vs distraction on the type of fractures observed was assessed for the subset of specimens that successfully achieved 20 mm of anterior shear. BFD+Fx was produced in five of 12 specimens, of which three had axial compression superimposed. The mechanical behaviour of the C6 inferior facets at the point of initial anatomical failure did not appear to be affected by intervertebral axial separation. This thesis presents the first large-cohort clinical investigation of CFD and provides quantitative information about the biomechanical response of the subaxial cervical facets to simulated traumatic loading. Axial compression generally increased facet surface strains and deflections when superimposed on intervertebral motions, and constrained intervertebral anterior shear can produce BFD+Fx. It is anticipated that this thesis will inform the development of improved preventative measures and provide data for the validation of models of cervical trauma.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 201

Spine Surgery

We are very excited to introduce this new book on spinal surgery, which follows the curriculum of the EUROSPINE basic and advanced diploma courses. The approach we take is a purely case-based one, in which each case illustrates the concepts surrounding the treatment of a given pathology, including the uncertainties and problems in decision-making. The readers will notice that in many instances a lack of evidence for a given treatment exists. So decisions taken are usually not a clearcut matter of black or white, but merely different shades of gray. Probably in a lot of cases, there is often more than one option to treat the patient. The authors were asked to convey this message to the reader, giving him a guidance as what would be accepted within the mainstream. In addition, the reader is provided with the most updated literature and evidence on the topic. Most of the authors are teachers in the courses of EUROSPINE or other national societies with often vast clinical experience and have given their own perspective and reasoning. We believe that the readers will profit very much from this variety and bandwidth of knowledge provided for them in the individual chapters. We have given the authors extensive liberty as to what they consider the best solution for their case. It is thus a representative picture of what is considered standard of care for spine pathologies in Europe. We hope that this book will be an ideal complement for trainees to the courses they take. Munich, Germany Bernhard Meyer Offenbach, Germany Michael Rauschman