Disc Injury Research Articles

Comparison of the Outcomes between AO Type B2 Thoracolumbar Fracture with and without Disc Injury after Posterior Surgery.

ObjectiveThe type AO B2 thoracolumbar fracture is a kind of flexion‐distraction injury and the effect of disc injury on treatment results of patients with B2 fracture remains unclear. The objective of the current study was to compare and analyze the outcomes in AO Type B2 thoracolumbar fracture patients with and without disc injuries in terms of the Cobb angle of kyphosis, the incidence of complication, and the rate of implant failure.MethodsThis is a retrospective study. Of the 486 patients with thoracolumbar fractures who underwent posterior fixation, 38 patients with AO type B2 injuries were included. All the patients were divided into two groups according to changes in the adjoining discs. Disc injury group A included 17 patients and no disc injury group included 21 patients. Clinical and radiologic parameters were evaluated before surgery, after surgery, and at follow‐up. Clinical outcomes included visual analogue scale (VAS) scores, incidence of complications, and incidence of implant failure. Radiologic assessment was accomplished with the Cobb angle (CA), local kyphosis (LK), percentage of anterior vertebral height (AVBH%), intervertebral disc height, and intervertebral disc angle. Fisher's precision probability tests were employed and chi square test were used to compare categorical variables. Paired sample t tests and independent‐sample t tests were used to compare continuous data.ResultsDisc injury mainly involved the cranial disc (15/19, 78.9%). The mean follow‐up period for the patients was 30.2 ± 20.1 months. No neurologic deterioration was reported in the patients at the last follow‐up. Radiological outcomes at the last follow‐up showed significant differences in the CA (18.59° ± 13.74° vs 8.16° ± 9.99°, P = 0.008), LK (12.74° ± 8.00° vs 6.55° ± 4.89°, P = 0.006), and %AVBH (77.16% vs 90.83%, P = 0.01) between the two groups.Implant failure occurred after posterior fixation in five patients with disc injury who did not undergo interbody fusion during the initial surgery. Additionally, in the subgroup analysis, interbody fusion in the implant failure group were significantly different than in the no implant failure group (0% vs 75%, P = 0.009).ConclusionsAO B2 fracture patients with disc injury have higher risk of complications, especially implant failure after posterior surgery. Interbody fusion should be considered in AO type B2 fracture patients with disc injury.

Study on the process of intervertebral disc disease by the theory of continuum damage mechanics

BackgroundRecently, more and more people suffer from low back pain triggered by lumbar degenerative disc disease. The mechanical factor is one of the most significant causes of disc degeneration. This study aims to explore the biomechanical responses of the intervertebral disc, and investigate the process of disc injury by the theory of continuum damage mechanics. MethodsA finite element model of the L4–L5 lumbar spine was developed and validated. The model not only considered changes in permeability coefficient with strain, but also included physiological factors such as osmotic pressure. Three loading conditions were simulated: (A) static loads, (B) vibration loads, (C) injury process. FindingsThe simulation results revealed that the facet joints shared massive stresses of the intervertebral discs, and prevented excessive lumbar spine movement. However, their asymmetrical position may have led to degeneration. The von Mises stress and pore pressure of annulus fibrosus showed significantly different trends under static loads and vibration loads. The von Mises stress of nucleus pulposus was not sensitive to vibration loads, but its pore pressure was conspicuously influenced by vibration loads. The injury first appeared at the posterior centre, and then, it gradually expanded along the edge of the intervertebral disc. With an increase in the loading steps, the damage rate of the intervertebral disc increased logarithmically. InterpretationThe variation in the biomechanical performance of the intervertebral disc could be attributed to the periodic movement of internal fluids. This study might be helpful for understanding the mechanism of intervertebral disc degeneration.

Dynamic elastic modulus assessment of the early degeneration model of an intervertebral disc in cynomolgus monkeys with one strike loading

ObjectiveDisc degeneration has long been associated with excessive mechanical loading or acute disc injury. Our goal is to perform a shock load on the functional units of the cynomolgus monkey intervertebral disc and analyze the degree of degeneration of the intervertebral disc through image analysis and comprehensive analysis. The organ model establishes a standard organ culture model and a non-invasive biomechanical evaluation protocol close to the early degeneration of the human intervertebral disc. MethodsAfter modeling, the cynomolgus monkey intervertebral discs were collected and loaded into the dynamic mechanical culture system. The physiological group was loaded with 10% high compressive deformation load for one second, the injury group was punctured with annulus fibrosus, the model group was loaded with 20–50% high compressive deformation, and the nutritional components were a high-glucose group and low-glucose group. After day 3 (short term) and day 10 (long term), samples were collected to analyze cell viability, histomorphology, image analysis for imaging and biomechanical changes. ResultsBoth the injury group and the 30–50% strain model group showed signs of early degeneration, including decreased instantaneous compressive stiffness, percent change in gray value, decreased cell viability, AF fissure, and percent increase in dynamic elastic modulus. The glucose-restricted group also showed signs of early disc degeneration in long-term cultures. ConclusionThis study shows that a single shock load can induce early degeneration of healthy cynomolgus monkey intervertebral discs, and 30% strain may be the nociceptive threshold for early degeneration of healthy intervertebral discs. More importantly, a non-invasive biomechanical evaluation scheme of Percentage change in dynamic modulus of elasticity is established, which solves the key scientific problem of how to non-invasively, quantitatively and sensitively detect the development process of early intervertebral disc degeneration and its degree of degeneration in an in vitro organ model.

Risk Factors for Postoperative Loss of Correction in Thoracolumbar Injuries Caused by High-Energy Trauma Treated via Percutaneous Posterior Stabilization without Bone Fusion.

Background and Objectives: Percutaneous pedicle screws were first introduced in 2001, soon becoming the cornerstone of minimally invasive spinal stabilization. Use of the procedure allowed adequate reduction and stabilization of spinal injuries, even in severely injured patients. This decreased bleeding and shortened surgical time, thereby optimizing outcomes; however, postoperative correction loss and kyphosis still occurred in some cases. Thus, we investigated cases of percutaneous posterior fixation for thoracolumbar injury and examined the factors affecting the loss of correction. Materials and Methods: Sixty-seven patients who had undergone percutaneous posterior fixation for thoracolumbar injury (AO classifications A3, A4, B, and C) between 2009 and 2016 were included. Patients with a local kyphosis angle difference ≥10° on computed tomography at the postoperative follow-up (over 12 months after surgery) or those requiring additional surgery for interbody fusion were included in the correction loss group (n = 23); the no-loss group (n = 44) served as the control. The degree of injury (injury level, AO classification, load-sharing score, local kyphosis angle, cuneiform deformity angle, and cranial and caudal disc injury) and surgical content (number of fixed intervertebral vertebrae, type of screw used, presence/absence of screw insertion into the injured vertebrae, and presence/absence of vertebral formation) were evaluated as factors of correctional loss and compared between the two groups. Results: Comparison between each group revealed that differences in the wedge-shaped deformation angle, load-sharing score, degree of cranial disc damage, AO classification at the time of injury, and use of polyaxial screws were statistically significant. Logistic regression analysis showed that the differences in wedge-shaped deformation angle, AO classification, and cranial disc injury were statistically significant; no other factors with statistically significant differences were found. Conclusion: Correction loss was seen in cases with damage to the cranial intervertebral disc as well as the vertebral body.

Comparison and optimization of sheep in vivo intervertebral disc injury model.

BackgroundThe current standard of care for intervertebral disc (IVD) herniation, surgical discectomy, does not repair annulus fibrosus (AF) defects, which is partly due to the lack of effective methods to do so and is why new repair strategies are widely investigated and tested preclinically. There is a need to develop a standardized IVD injury model in large animals to enable comparison and interpretation across preclinical study results. The purpose of this study was to compare in vivo IVD injury models in sheep to determine which annulus fibrosus (AF) defect type combined with partial nucleus pulposus (NP) removal would better mimic degenerative human spinal pathologies.MethodsSix skeletally mature sheep were randomly assigned to one of the two observation periods (1 and 3 months) and underwent creation of 3 different AF defect types (slit, cruciate, and box‐cut AF defects) in conjunction with 0.1 g NP removal in three lumbar levels using a lateral retroperitoneal surgical approach. The spine was monitored by clinical CT scans pre‐ and postoperatively, at 2 weeks and euthanasia, and by magnetic resonance imaging (MRI) and histology after euthanasia to determine the severity of degeneration (disc height loss, Pfirrmann grading, semiquantitative histopathology grading).ResultsAll AF defects led to significant degenerative changes detectable on CT and MR images, produced bulging of disc tissue without disc herniation and led to degenerative and inflammatory histopathological changes. However, AF defects were not equal in terms of disc height loss at 3 months postoperatively; the cruciate and box‐cut AF defects showed significantly decreased disc height compared to their preoperative height, with the box‐cut defect creating the greatest disc height loss, while the slit AF defect showed restoration of normal preoperative disc height.ConclusionsThe tested IVD injury models do not all generate comparable disc degeneration but can be considered suitable IVD injury models to investigate new treatments. Results of the current study clearly indicate that slit AF defect should be avoided if disc height is used as one of the main outcomes; additional confirmatory studies may be warranted to generalize this finding.

Unilateral Cervical Facet Fractures: Relevance of Acute Disc Injury in Conservative Treatment Failure.

Case-control study. Analyze association between imaging factors related to the failure of conservative treatment in isolated subaxial cervical facet fractures. Facet fracture (F1, F2, and F3 AOSpine) may be stable or unstable depending on clinical and imaging variables, which are not well established. As a result, differences in fracture management lead to differences in surgical or conservative indications, and there is no evidence to predict conservative treatment failure. Patients were categorized into two groups: six patients (16.2%) with conservative treatment failure (defined as the appearance of neurological symptoms, listhesis >3.5 mm, kyphotic deformation >11°, and/or non-union), and 31 patients (83.7%) with successful conservative management (defined as complete consolidation confirmed by computed tomography [CT] at the 6-month followup). All participants were fitted with rigid collars of the Miami type, and standardized follow-up was performed until consolidation or failure. CT and magnetic resonance imaging (MRI) was used to examine imaging characteristics. Sagittal balance parameters were assessed using CT, and signs of acute disc injury, prevertebral edema, facet synovitis, and interspinous hyperintense signal were assessed using MRI. Thirty-seven patients were diagnosed with unilateral cervical facet fractures between 2009 and 2020. In this sample, acute disc injury had a significative association to failure of conservative treatment in F2 and F3 AOSpine facet fractures, 100% of the failure group presented with traumatic disc injury compared to 9.7% of the successful group, for the other variables: prevertebral edema, 83.7% vs. 41.9%; facet synovitis, 100% vs. 77.4%; and interspinous hyperintensity, 71.4% vs. 38.7%, respectively. With conservative management, all F1 fractures healed successfully. Conservative treatment failed in 20% of F2 fractures and 50% of F3 fractures, respectively. In terms of cervical sagittal balance parameters, there were no significant differences between groups. Conservative management was successful in all F1 fractures. In F2 and F3 types, there was a significant association between acute disc injury and conservative treatment failure.

CRISPR-Cas9-mediated loss of function of β-catenin attenuates intervertebral disc degeneration

Intervertebral disc degeneration is a very common medical condition causing pain and disability, and it cannot be reversed by available treatment options. Here we report that targeting β-catenin, a pivotal factor associated with disc degeneration, ameliorates disc degeneration in a mouse model of disc injury. Degenerative changes in the disc in response to disc injury include decompression of nucleus pulposus (NP), replacement of notochordal cells in the NP by chondrocyte-like cells, and disorganization of annulus fibrosus (AF). Importantly, downregulation of β-catenin through intradiscal injection of CRISPR-Cas9-expressing adeno-associated virus significantly mitigated all these pathological changes, by preserving notochordal cells and attenuating chondro-osteogenesis in the NP, as well as maintaining the AF structure. Moreover, β-catenin loss-of-function decelerated the rapid induction of catabolic reactions in disc matrix and attenuated pain-related neural events during disc degeneration. Thus, our data demonstrate that targeting β-catenin in disc cells through CRISPR-Cas9 has multifaceted therapeutic effects on disc degeneration, and we suggest that β-catenin plays a fundamental role in the remodeling and degenerative processes of the disc. In addition, this study proposes that CRISPR-Cas9 is a useful tool for identifying new drug targets and developing therapeutic strategies for disc degeneration.

Predictors of adverse events after percutaneous pedicle screws fixation in patients with single-segment thoracolumbar burst fractures

BackgroundPercutaneous pedicle screw fixation (PPSF) is the primary approach for single-segment thoracolumbar burst fractures (TLBF). The healing angle at the thoracolumbar junction is one of the most significant criteria for evaluating the efficacy of PPSF. Therefore, the purpose of this study was to analyze the predictors associated with the poor postoperative alignment of the thoracolumbar region from routine variables using a support vector machine (SVM) model.MethodsWe retrospectively analyzed patients with TLBF operated at our academic institute between March 1, 2014 and December 31, 2019. Stepwise logistic regression analysis was performed to assess potential statistical differences between all clinical and radiological variables and the adverse events. Based on multivariate logistic results, a series of independent risk factors were fed into the SVM model. Meanwhile, the feature importance of radiologic outcome for each parameter was explored. The predictive performance of the SVM classifier was evaluated using the area under the receiver operating characteristic curve (AUC), accuracy (ACC) and confusion matrices with 10-fold cross-validation, respectively.ResultsIn the recruited 150 TLBFs, unfavorable radiological outcomes were observed in 53 patients (35.33%). The relationship between osteoporosis (p = 0.036), preoperative Cobb angle (p = 0.001), immediate postoperative Cobb angle (p = 0.029), surgically corrected Cobb angle (p = 0.001), intervertebral disc injury (Score 2 p = 0.001, Score 3 p = 0.001), interpedicular distance (IPD) (p = 0.001), vertebral body compression rate (VBCR) (p = 0.010) and adverse events was confirmed by univariate regression. Thereafter, independent risk factors including preoperative Cobb angle, the disc status and IPD and independent protective factors surgical correction angle were identified by multivariable logistic regression. The established SVM classifier demonstrated favorable predictive performance with the best AUC = 0.93, average AUC = 0.88, and average ACC = 0.87. The variables associated with radiological outcomes, in order of correlation strength, were intervertebral disc injury (42%), surgically corrected Cobb angle (25%), preoperative Cobb angle (18%), and IPD (15%). The confusion matrix reveals the classification results of the discriminant analysis.ConclusionsCritical radiographic indicators and surgical purposes were confirmed to be associated with an unfavorable radiographic outcome of TLBF. This SVM model demonstrated good predictive ability for endpoints in terms of adverse events in patients after PPSF surgery.

Residual stability of the craniovertebral segment in its various injuries

Residual stability of craniovertebral segment in the most common injuries (odontoid process fractures, ring fractures of C2, Atlas fractures, etc.) was sudied in experiment. The study was performed in 7 cadaveral craniovertebral blocks. The range of movement before and after injuires modelling, the estimation of force that caused the vertebrae displacement using special loading test device were detected. It was shown that in any injury without vertebrae dislocation craniovertebral segment possessed the residual stability. The minor stability was noted in odontoid prosess fractures of II and III types and butchersfractures, the major stability was in the intervertebral disc injuries of C2-C3 and occipital condyle fractures. On the base of experimental and clinical data the conclusion was done that fixation of cervical spine using head support with frontal fixative or halo apparatus were indicated for cranivertebral segement injuries without vertebrae dislocation. In dislocation of vertebrae it was necessary to reduce the dislocation and open surgical intervention for stabilization.

Intervertebral disc injury is the mainspring for the postoperative increase in Cobb Angle after thoracolumbar burst fracture.

A single-institution retrospective study of a cohort of patients who underwent internal fixation spine surgery for thoracolumbar burst fracture (TLBF). To observe the imaging manifestations of intervertebral disc changes in TLBF, to analyze the relationship between the degree of disc injury and the Cobb angle increase. We retrospectively analyzed the data of patients who underwent short-segment pedicle screw instrumentation in the spinal surgery department of a single hospital between January 2014 and December 2017 (n = 90). According to the magnetic resonance imaging characteristics of the superior intervertebral disc tissue of the injured vertebrae before the operation, the intervertebral disc injury was divided into three types, which was used for group allocation: group A, uninjured intervertebral disc group; group B, mild intervertebral disc injury group; and group C, severe intervertebral disc injury group. The main imaging results of the three groups Cobb, IVA, IHI, AHIV, and VAS were compared among groups. Ninety patients were included in the study (n = 38, 32, and 20, in groups A, B, and C, respectively). There was no statistically significant difference in demographics among the three groups (p > .05). 1-year post-surgery, the Cobb angle in group C differed significantly from that in groups A and B (p < .01). There was a significant difference in Cobb angle between groups A and B after internal fixation was removed for 6 months. At 1-year post-surgery, the IHI group C differed significantly from groups A and B (p < .01), while groups A and B were similar (p = .102); however, at 6 months after the internal fixation was removed, the IHI differed significantly between these two groups, also the AHIV between groups A and B was statistically significant (p < .01). The VAS pain score was similar among the three groups. Pearson's test showed that the increase in the Cobb angle was moderately correlated with IVA and IHI, and weakly correlated with AHIV. For TLBF with an intervertebral disc injury, the presurgical degree of intervertebral disc injury is the main reason for the post-surgery increase in the Cobb angle. Thus, diagnosis and treatment of this kind of patient require attention to the risk of spinal deformity.

Correlation between preoperative magnetic resonance imaging findings and bone cement leakage after percutaneous vertebral augmentation.

BACKGROUND: Studies have shown that the endplate injuries in patients with osteoporotic vertebral compression fracture are related to the intradiscal cement leakage after percutaneous vertebral augmentation. OBJECTIVE: To investigate the correlation between preoperative magnetic resonance imaging findings and intradiscal cement leakage after percutaneous vertebral augmentation, and to analyze whether endplate fractures and adjacent intervertebral disc injuries affect the incidence of intradiscal cement leakage. METHODS: Totally 182 patients with single-level osteoporotic vertebral compression fractures admitted to the Affiliated Hospital of Xuzhou Medical University from September 2018 to December 2019 were selected, of which 110 received percutaneous kyphoplasty treatment, 72 cases received percutaneous vertebroplasty treatment. According to the preoperative magnetic resonance imaging images, the condition of the adjacent intervertebral disc injury and endplate fracture of the fractured vertebral body was evaluated. According to whether there is intradiscal cement leakage after the operation, the patients were divided into a leakage group (n=32) and a non-leakage group (n=150). A univariate analysis was performed on the correlation between the patient’s age, gender, surgical spinal level, surgical method, endplate fracture, adjacent intervertebral disc injury and intradiscal cement leakage, and then a multivariate binary logistics regression model analysis was performed. The study was approved by the Medical Ethics Committee of the Affiliated Hospital of Xuzhou Medical University. RESULTS AND CONCLUSION: (1) Of the 182 patients, 63 had endplate fractures and 98 had adjacent intervertebral disc injuries. In all patients, 32 cases of intradiscal cement leakage occurred after percutaneous vertebral augmentation;the leakage rate of the endplate fracture group was higher than that of the non-endplate fracture group (P 0.05). (3) The binary logistics regression analysis showed that the endplate fracture was the independent risk factor for intradiscal cement leakage after percutaneous vertebral augmentation;adjacent intervertebral disc injury, age, gender, surgical method, and surgical spinal level were not the risk factors for intradiscal cement leakage. (4) Related analysis showed that there was a significant correlation between the endplate fracture and the intervertebral disc injury (r=0.47, P=0.000). (5) The results showed that the endplate fracture found in the preoperative magnetic resonance imaging was a risk factor for intradiscal cement leakage, and the intervertebral disc injury was not the influence factor of intradiscal cement leakage;the intervertebral disc injury was significantly related to the endplate fracture in osteoporotic vertebral compression fractures patients. (English) [ABSTRACT FROM AUTHOR] 背景：有研究表明，骨质疏松性椎体压缩骨折患者伴随的终板损伤与经皮椎体强化后骨水泥椎间盘渗漏有关。 目的：探讨经皮椎体强化后骨水泥椎间盘渗漏与术前MRI发现的相关性，分析终板骨折及邻近椎间盘损伤对骨水泥椎间盘渗漏的影响。 方法：选择2018年9月至2019年12月徐州医科大学附属医院收治的单节段骨质疏松性椎体压缩骨折患者182例，其中110例接受经皮椎体后 凸成形骨水泥注射治疗，72例接受经皮椎体成形骨水泥注射治疗。根据术前MRI片评估骨折椎体相邻椎间盘损伤和终板骨折情况。根据术 后是否出现椎间盘骨水泥渗漏分为渗漏组(n=32)和无渗漏组(n=150)，对患者年龄、性别、手术椎体部位、手术方式、终板骨折情况、相邻 椎间盘损伤情况与骨水泥椎间盘渗漏的相关性进行单因素分析，再进行多因素的二元logistics回归模型分析。研究经徐州医科大学附属医 院医学伦理委员会批准。 结果与结论：①182例患者中，术前63例存在终板骨折，98例存在邻近椎间盘损伤；所有患者中，32例椎体强化后发生骨水泥椎间盘渗 漏，终板骨折组的渗漏率高于无终板骨折组(P 0.05)；③二元logistics回归分析显示，终板骨折是强化后 发生骨水泥椎间盘渗漏的独立危险因素，邻近椎间盘损伤、年龄，性别，手术方式、手术椎体部位不是骨水泥椎间盘渗漏的危险因素；④ 相关分析显示，终板骨折与椎间盘损伤存在显著相关性(r=0.47，P=0.000)；⑤结果表明，术前MRI发现的终板骨折是骨水泥椎间盘渗漏的 危险因素，而椎间盘损伤并非骨水泥椎间盘渗漏的影响因素，椎间盘损伤与终板骨折在骨质疏松性椎体压缩骨折患者中存在明显相关性。 (Chinese) [ABSTRACT FROM AUTHOR] Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo zu zhi gong cheng yan jiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Некоторые особенности дископатий у собак

Currently, vertebrogenic dyskinesias of various nature are widespread in urban dogs. Among them, there are often herniated discs associated with degenerative processes in various parts of the spinal column in dogs. The article discusses different types of intervertebral disc disease in animals of different breeds and ages, analyzes the frequency of their occurrence, considers the breed characteristics of the distribution of certain pathologies of the spine, topical features of herniated intervertebral discs of various types, as well as risk factors for discopathy in dogs. Among the animals studied, intervertebral disc disease Hansen Type 1 and Hansen Type 2 was more common in dogs of chondrodystrophic breeds (dachshund and French bulldog) and in dogs of large breeds (German shepherd and mestizos). Animals of the older age group are more prone to vertebrogenic dyskinesias. Intervertebral disc injuries were more common in the most mobile parts of the spine, and overweight animals were especially susceptible to them.

Lumbar Disc Injury: Mechanisms and Intervention Options

Low back pain is prevalent in sport and the lumbar disc is a pain generator. Conservative care of these physically demanding patients is not consistent as outcome data has not established optimal strategies. Investigating disc injury mechanisms using experimental models will contribute to the creation of treatment strategies that will take into effect movements to avoid and minimize to reduce unwanted strain on the injured tissues throughout the recovery process. Additionally, how disc tissue acquires nutrition would help provide insight into activities that may facilitate the ability of disc tissue to sustain health and promote optimal healing. Rotational forces and compression in trunk-flexed positions may inflict injury to the annulus and endplate structures. Activity to facilitate nutrients through the endplate into the nucleus of the disc and restriction of exasperating movements may be effective in returning athletes to their desired levels of performance efficiently. The purpose of this review is to inquire possible disc injury mechanisms and how they occur in sport. It will also address recommendations for treatment interventions based on disc healing and metabolism evidence.

Do triangular fibrocartilage complex foveal injuries affect the clinical outcome of ulnar shortening osteotomy for ulnar impaction syndrome?

BackgroundUlnar shortening osteotomy (USO), as its name implies, is used to shorten the ulna. It subsequently tightens the triangular fibrocartilage complex (TFCC) and ulnar wrist. TFCC foveal insertion is a primary stabilizer of the distal radioulnar joint. It is unclear whether USO is effective in TFCC foveal injuries. The purpose of this study was to review the clinical outcomes of ulnar shortening osteotomies with and without TFCC foveal injuries. MethodsWe retrospectively reviewed patients with ulnar wrist pain treated with USO and wrist arthroscopy including the distal radioulnar joint (DRUJ). Sixty-five patients were included in this study. An algorithm was used to guide surgical decision-making. After arthroscopic confirmation of ulnar impaction syndrome, we performed USO with a locking compression plate (mean length of shortening, 2.7 mm; range, 1–7.5 mm). The flattened TFCC disc due to ulnar shortening was confirmed arthroscopically. If the DRUJ was unstable after USO, we repaired the TFCC foveal insertion. ResultsThere were 32 post-traumatic and 33 idiopathic cases. We detected TFCC disc injuries in 34 wrists and TFCC foveal injuries in 33 wrists; both types were found in 15 wrists. TFCC foveal injuries were not significantly correlated with patient age, history of trauma, or clinical outcome. Most patients showed good clinical outcomes; 31 of 65 patients had preoperative DRUJ instability, with a significant number having foveal but not disc injuries. ConclusionUSO achieved reasonable outcomes, even in patients with TFCC foveal injuries. In cases demonstrating ulnar impaction, USO should be prioritized over TFCC repair.

Use of Computed Tomography Compression Ratio in Diagnosis of Disc Injuries and Posterior Ligamentous Complex Injuries in Osteoporotic Thoracolumbar Compression Fractures

Background: Osteoporotic compression fractures are common among the elderly. It is important to predict the posterior ligamentous complex (PLC) and disc injuries in computed tomography (CT) scans of patients with magnetic resonance imaging (MRI) contraindications. Objectives: To determine the role of the CT compression ratio (CTCR) in diagnosing PLC and disc injuries and to compare it with the loss of vertebral body height (LOVBH) in osteoporotic thoracolumbar compression fractures. Patients and Methods: A total of 91 consecutive patients with vertebral fractures were included as the study population. The PLC and disc injuries were assessed using MRI, and the following radiological parameters were determined based on CT scans for further MRI examinations: CTCR, LOVBH, local kyphosis (LK), interspinous widening (ISW), vertebral translation (VBT), and posterior structures fractures (PSF). Statistical analysis was performed to identify the diagnostic value of CT features in PLC and disc injuries. Results: The PLC injuries were detected in 9/91 cases, and the number of disc injuries was 47/91. Neither CTCR nor LOVBH was associated with PLC injuries (P &gt; 0.05). However, the CTCR was associated with disc injuries (P &lt; 0.05), with an optimal threshold of 1.755 (sensitivity, 68.1%; specificity, 79.5%), while the LOVBH was not significantly associated with disc injuries. Based on the results, VBT was significantly related to PLC and disc injuries (P &lt; 0.05). Conclusion: The injured vertebral CTCR was associated with disc injuries rather than PLC injuries, suggesting that compression fractures are relatively stable with less PLC injury. Overall, CTCR is a useful indicator reflecting the compression degree of the injured vertebrae; it is also a valid predictor of disc injuries.

Heterogeneous macrophages contribute to the pathology of disc herniation induced radiculopathy

Macrophages play important roles in the progression of intervertebral disc herniation and radiculopathy. To better understand the roles of macrophages in this process, we developed a new mouse model that mimics human radiculopathy. A preclinical randomized animal study. Three types of surgeries were performed in randomly assigned Balb/c mice. These were spinal nerve exposure, traditional anterior disc puncture, and lateral disc puncture with nerve exposure (n=16/group). For the nerve exposure group, the left L5 spinal nerve was exposed without disc injury. For the traditional anterior puncture, L5/6 disc was punctured by an anterior approach as previously established. For lateral puncture with nerve exposure, the left L5 spinal nerve was exposed by removing the psoas major muscle fibers, and the L5/6 disc was punctured laterally on the left side with a 30G needle, allowing the nucleus to protrude toward the L5 spinal nerve. Mechanical hyperalgesia (pain sensitivity) of hind paws was assessed with electronic von Frey assay on alternative day for up to 2 weeks. MRI, histology, and immunostaining were performed to confirm disc herniation and inflammation. Ipsilateral pain in the lateral puncture with nerve exposure group was significantly greater than the other groups. Pro-inflammatory cytokines IL-1β and IL-6 were markedly elevated at the hernia sites of both puncture groups and the spinal nerve of lateral puncture with never exposure group on postoperative day 7. Heterogeneous populations of macrophages were detected in the infiltration tissue of this mouse model and in tissue from patients undergone discectomy. We have established a new mouse model that mimics human radiculopathy and demonstrated that a mixed phenotype of macrophages contribute to the pathogenesis of acute discogenic radiculopathy. This study provides a clinically relevant in vivo animal model to elucidate complex interactions of disc herniation and radicular pain, which may present opportunities for the development of macrophage-anchored therapeutics to manage radiculopathy.

Cervical spine injury: A review

The aim of this review is to re-examine the role of cervical spine imaging in the context of new guidelines and technical advances in imaging techniques. MRI and multislice CT technology have made rapid advances. The rapid primary clinical survey should be followed by lateral cervical spine, chest and pelvic radiographs. If a patient is unconscious then CT of the brain and at least down to C3 is very useful. The cranio-cervical scans should be a maximum of 2 mm thickness, and probably less, as undisplaced type II peg fractures, can be invisible even on 1 mm slices with reconstructions. If the lateral cervical radiograph and the CT scan are negative, then MRI is the investigation of choice to exclude instability. Patients with focal neurological deficit, sign of cord or disc injury, and patients whose surgery require pre-operative cord assessment should be imaged by MRI. It is also the investigation of choice for evaluating the complications and late sequela of trauma. If the patient is to have an MRI scan, do a sagittal STIR sequence of the entire vertebral column to exclude non-contiguous injuries, which, since the advent of MRI. Any areas of oedema or collapse then require detailed CT scanning. The aim of this review is to re-examine the role of cervical spine imaging in the context of new guidelines and technical advances in imaging techniques.

Is only Anterior Stabilization Enough in Three-Column Injury of Subaxial Cervical Spine? - A Long-Term Retrospective Analysis of 78 Patients.

Study Design:This was a retrospective study.Purpose:The purpose was to retrospectively evaluate long-term outcome of anterior stabilization in three-column injury of the subaxial cervical spine.Overview of Literature:Literature shows varied results regarding the approach to be chosen. Most studies prefer a combined approach since biomechanically forms more stable construct. The isolated posterior approach is preferred by many as it is easy to reduce and fix three-column injuries. There are very few studies which show the isolated anterior approach to be better than the other two.Materials and Methods:Seventy-eight patients of three-column injury operated by anterior approach with follow-up of atleast 2 years were included and retrospectively analyzed. Clinical data included age, sex, time to surgery, methods of reduction, postoperative mobilization, and neurological evaluation using the ASIA scale. Radiological data included pre- and postreduction X-ray, computed tomography, and magnetic resonance imaging (MRI). X-rays taken post-operatively at 1,3, 6 months, 1yr and 2yrs. Variables like fracture type (AO Classification), overall alignment, localized kyphosis, time for fusion and grade of fusion mass were noted.Results:Of 78 patients, 61 had bifacetal dislocation and 17 unifacetal. The most common site was C5-6, followed by C3-4 and C6-7. The mean patient age was 35.98 years with 60 males and 18 females. The mean time to surgery was 4.4 days. Forty dislocations were reduced by closed method and 38 by open anterior approach. Fifty-six percent of patients had traumatic disc injury on MRI. All are managed by single-level anterior cervical discectomy and fusion with iliac crest autograft for fusion. The mean preoperative lordosis: 4.44° (range −13.4° to 25°) and mean postoperative lordosis: 28.57° (P < 0.0001) mean loss of alignment: 2.59° by 2 years, 100% fusion with mean time – 22.82 weeks, neurological recovery in 34.6% with atleast one grade improvement in ASIA scale. No neurological worsening or need for revision surgery was observed.Conclusion:The goal of surgery in cervical injury is bony stabilization and fusion using a least morbid approach and one with good long-term outcome. Above study concludes that only anterior stabilization after reduction of three-column injury would suffice with good long-term outcome, thereby obviating need for global fusion.

The hippo pathway orchestrates cytoskeletal organisation during intervertebral disc degeneration

Yes-associated protein (YAP) activity responded to physical and mechanical cues such as extracellular matrix (ECM), cell density and the mechanical regulation of YAP controlled cellular proliferation and inhibition of apoptotic signals. The intervertebral disc (IVD) comprises a heterogeneous population of cells, including those of the nucleus pulposus (NP) and annulus fibrosus (AF), which are diverse in phenotype, partly due to the different ECM and mechanical loads they experience. How do IVD cells sense microenvironment and what is the relationship between YAP and cytoskeleton in the process of intervertebral disc degeneration (IDD) are not well understood. First, Hippo pathway and cytoskeleton organisation were assessed in the NP and AF of immature (4 weeks), mature (14 weeks), aged (50 weeks), and degenerated (14 weeks, 4 weeks after annulus puncture) IVDs. Second, to assess the effect of ECM composition and cell density on cytoskeleton and YAP levels, we seeded cells at different densities on three types of ECM. In this study, YAP and F-actin activity decreased gradually with age in natural IDD. Hippo signalling was suppressed in the early stages of disc injury, demonstrating the potential for endogenous repair, but this repair did not prevent further disc degeneration. β-tubulin and vimentin filaments provide the cell with its shape and its elastic properties in resisting mechanical forces. The Hippo pathway and cytoskeleton were shown to be regulated by cell density and the ECM composition.

Classification of unilateral cervical locked facet with or without lateral mass-facet fractures and a retrospective observational study of 55 cases

This study describes a morphology-based unilateral cervical facet interlocking classification in an attempt to clarify the injury mechanism, instability, neurological deficits, radiological features, and determine optimum management strategies for these injuries. A total of 55 patients with unilateral cervical locked facet (UCLF) involving C3 to C7 were identified between January 1, 2012 and December 1, 2019. The injuries were classified into three types, and they were further divided into six subtypes using three-dimensional computed tomography. The injury mechanism, clinical features, neurological deficits, and imaging characteristics were analyzed, and the appropriate treatment strategies for UCLF were discussed. UCLFs were divided into the following six subtypes: UCLF without lateral mass-facet fracture (type I) in nine cases, with superior articular process fracture (type II A) in 22, with inferior articular process fracture (type II B) in seven, both superior and inferior articular process fractures (type II C) in four, with lateral mass splitting fracture (type III A) in three, and with lateral mass comminution fractures (type III B) in ten. A total of 22 (40.0%) of the 55 patients presented with radiculopathy, and 23 patients (41.8%) had spinal cord injuries. The subtype analyses showed high rates of radiculopathy in types II A (68.2%) and II C (75.0%), as well as significant spinal cord injury in types I (77.8%) and III (61.5%). Destruction of the facet capsule was observed in all patients, but the injury of disc, ligamentous complex, and vertebra had a significant difference among the types or subtypes. The instability parameters of the axial rotation angle, segmental kyphosis, and sagittal displacement showed significant differences in various types of UCLF. Closed reduction by preoperative and intraoperative general anesthesia traction was achieved in 27 patients (49.1%), and successful rate of closed reduction in type I (22.2%) was significantly lower than that in type II (51.5%) and type III (61.5%). A total of 35 of 55 patients underwent a single anterior fixation and fusion, 10 patients were treated with posterior pedicle and (or) lateral mass fixation, and combined surgery was performed in ten patients. Ten patients (18.2%) with a poor outcome were observed after first surgery. Among them, 3 patients treated with a single anterior surgery had persistent or aggravated radiculopathy and posterior approach surgery with ipsilateral facet resection, foramen enlargement, and pedicle and (or) lateral mass screw fixation was performed immediately, 5 patients treated with a short-segment posterior surgery showed mild late kyphosis deformity, and 2 patients with vertebral malalignment were encountered after anterior single-level fusion during the follow-up. This retrospective study indicated that UCLF is a rotationally unstable cervical spine injury. The classification proposed in this study will contribute to understanding the injury mechanism, radiological characteristics, and neurological deficits in various types of UCLF, which will help the surgeons to evaluate the preoperative closed reduction and guide the selection of surgical approach and fusion segment.