Search

OBJECTIVE Achieving solid fusion of the lumbosacral junction continues to be a challenge in long-segment instrumentation to the sacrum. The purpose of this study was to test the condition of adding sacral anchors through an S1 alar screw (S1AS) and multirod construct relative to using S1 pedicle screws (S1PSs) alone with sacroiliac fixation in lumbosacral junction augmentation. METHODS Seven fresh-frozen human lumbar-pelvic spine cadaveric specimens were tested under nondestructive moments (7.5 Nm). The ranges of motion (ROMs) in extension, flexion, left and right lateral bending (LB), and axial rotation (AR) of instrumented segments (L3–S1); the lumbosacral region (L5–S1); and the adjacent segment (L2–3) were measured, and the axial construct stiffness (ACS) was recorded. The testing conditions were 1) intact; 2) bilateral pedicle screw (BPS) fixation at L3–S1 (S1PS alone); 3) BPS and unilateral S2 alar iliac screw (U-S2AIS) fixation; 4) BPS and unilateral S1AS (U-S1AS) fixation; 5) BPS and bilateral S2AIS (B-S2AIS) fixation; and 6) BPS and bilateral S1AS (B-S1AS) fixation. Accessory rods were used in testing conditions 3–6. RESULTS In all directions, the ROMs of L5–S1 and L3–S1 were significantly reduced in B-S1AS and B-S2AIS conditions, compared with intact and S1PS alone. There was no significant difference in reduction of the ROMs of L5–S1 between B-S1ASs and B-S2AISs. Greater decreased ROMs of L3–S1 in extension and AR were detected with B-S2AISs than with B-S1ASs. Both B-S1ASs and B-S2AISs significantly increased the ACS compared with S1PSs alone. The ACS of B-S2AISs was significantly greater than that of B-S1ASs, but with greater increased ROMs of L2–3 in extension. CONCLUSIONS Adding sacral anchors through S1ASs and a multirod construct was as effective as sacropelvic fixation in lumbosacral junction augmentation. The ACS was less than the sacropelvic fixation but with lower ROMs of the adjacent segment. The biomechanical effects of using S1ASs in the control of long-instrumented segments were moderate (better than S1PSs alone but worse than sacropelvic fixation). This strategy is appropriate for patients requiring advanced lumbosacral fixation, and the risk of sacroiliac joint violation can be avoided.

Low back pain (LBP) is a common clinical symptom, and the prevalence is ranged from 60% to 70%. With the deepening of basic research, the development of intervertebral disc regeneration-oriented cell therapy, especially stem and progenitor cells therapy, showed good research prospects and was expected to become new methods of treatment for LBP. Our study is aimed at analyzing the scientific output of stem and progenitor cells in intervertebral discs and at driving future research into new publications. Researches focused on this file were searched from the Science Citation Index Expanded (SCI-E) of the Web of Science (WOS) core collection database and were screened according to inclusion criteria. We evaluated and visualized the results, including annual publications, citations, authors, organizations, countries, research directions, funds, and journals by bibliometric website, VOSviewer, and Citespace softwares on May 27, 2022. A total of 450 original articles and reviews were included, and the overall trend of the number of publications rapidly increased. In worldwide, China and the USA were the leading countries for research production. The retrieved 450 publications received 14322 citations, with an average of 31.83 citations and an H-index of 62. The most high-yield author, organization, country, research directions, funds, and journals were Chen QX from Zhejiang University, Zhejiang University, China, Cell Biology, National Natural Science Foundation of China, and Spine, respectively. Keywords cluster analysis showed the research hotspots in the future, including “human intervertebral disc”, “adipose-derived mesenchymal stem cell”, “intervertebral disc degeneration”, “degenerative disc model”, “nucleus pulposus regeneration”, “human cartilage”, “3d culture”, “shrinkage-free preparation”, and “polylactide disc”. Furthermore, with accumulating evidence demonstrating the role of stem and progenitor cells in intervertebral discs, “microenvironment”, “activation”, “intervertebral disc degeneration”, and “oxidative stress” are becoming the research frontiers and trends.

Hongtao Ding, Yong Hai, Yuzeng Liu, Li Guan, Aixing Pan, Xinuo Zhang, Bo Han, Yue Li, Peng Yin Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of ChinaCorrespondence: Yong Hai; Yuzeng Liu, Department of Spine Surgery, Beijing Chao-Yang Hospital, Capital Medical University of China, Beijing, People’s Republic of China, Tel +86 10-85231229 ; +86 13801221889 ; +86 13811552832, Email prof.haiyong@yahoo.com; yong.hai@ccmu.edu.cn; beijingspine2010@163.comStudy Design: This was a prospective randomized controlled trial study.Objective: To elucidate clinical and radiographic outcomes and complications of cortical bone trajectory (CBT)-screw fixation in patients with osteoporosis at 24-month follow-up and to compare the results with those after transforaminal lumbar interbody fusion (TLIF) using traditional pedicle screw (PS) fixation.Methods: We enrolled 124 patients and randomly assigned them to two groups (each group had 62 participants). The primary outcome was fusion rate. Secondary outcomes were VAS, Oswestry Disability Index (ODI), and Japanese Orthopaedic Association (JOA) scores, operation duration, incision length, estimated blood loss, drainage volume, radiological outcomes, and complications.Results: At the 6- and 12-month follow-up points, similar fusion rates were observed based on CT scans in both groups (P=0.583 and 0.583). CBT provided significantly better short-term functional status at 3 months postoperation on ODI and JOA scores (P=0.012 and 0) and similar improvements in pain intensity and functional status at other follow-up points. In addition, CBT resulted in significantly better surgical characteristics. Notably, CBT fixation led to lower incidence of screw loosening (P=0.006).Conclusion: CBT-screw fixation for single-level lumbar fusion in patients with osteoporosis provided improvement in clinical symptoms comparable to that of TLIF using PS fixation. Significantly better lumbar stability was found in the CBT group. We suggest that CBT-screw fixation is a reasonable and superior alternative to PS in TLIF in osteoporosis.Trial Registration Number: ChiCTR1900022658.Date of Registration: April 20, 2019.Keywords: cortical bone-trajectory screw, pedicle screw, lumbar fusion, osteoporosis, randomized controlled trial

Artificial bone materials are of high demand due to the frequent occurrence of bone damage from trauma, disease, and ageing. Three-dimensional (3D) printing can tailor-make structures and implants based on biomaterial inks, rendering personalized bone medicine possible. Herein, we extrusion-printed 3D silk fibroin (SF) scaffolds using mixed inks from SF and sodium alginate (SA), and post-mineralized various calcium phosphates to make hybrid SF scaffolds. The effects of printing conditions and mineralization conditions on the mechanical properties of SF scaffolds were investigated. The SF scaffolds from ~10 wt% SF ink exhibited a compressive modulus of 240 kPa, which was elevated to ~1600 kPa after mineralization, showing a significant reinforcement effect. Importantly, the mineralized SF 3D scaffolds exhibited excellent MC3T3-E1 cell viability and promoted osteogenesis. The work demonstrates a convenient strategy to fabricate SF-based hybrid 3D scaffolds with bone-mimetic components and desirable mechanical properties for bone tissue engineering.

Study Design: Modified Delphi study. Objective: The objective of this study was to establish expert consensus on the application of lateral lumbar interbody fusion (LLIF) by using the modified Delphi study. Methods: From June 2019 to March 2020, Members of the Chinese Study Group for Lateral Lumbar Spine Surgery were selected to collect expert feedback using the modified Delphi method where 65 spine surgeons from all over China agreed to participate. Four rounds were performed: 1 face-to-face meeting and 3 subsequent survey rounds. The consensus was achieved with ≥a 70.0% agreement for each question. The recommendation of grade A was defined as ≥90.0% of the agreement for each question. The recommendation of grade B was defined as 80.0-89.9% of the agreement for each question. The recommendation of grade C was defined as 70.0-79.9% of the agreement for each question. Results: A total of 65 experts formed a panelist group, and the number of questionnaires collected was 63, 59, and 62 in the 3 rounds. In total, 5 sections, 71 questions, and 382 items achieved consensus after the Delphi rounds including summary; preoperative evaluation; application at the lumbar spinal stenosis, lumbar disc herniation, lumbar spondylolisthesis, adult degenerative scoliosis, postoperative adjacent segmental degeneration, and revision surgery; complications; and postoperative follow-up evaluation of LLIF. Conclusion: The modified Delphi method was utilized to ascertain an expert consensus from the Chinese Study Group for Lateral Lumbar Spine Surgery to inform clinical decision-making in the application of LLIF. The salient grade A recommendations of the survey are enumerated.

STUDY DESIGN Systematic review and meta-analysis. OBJECTIVE The purpose of the study was to compare the outcomes and after spinal fusion with or without iliac screw (IS) insertion for patients with adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA The number of patients undergoing multilevel spinal stabilization for the treatment of ASD is growing. However, the selection of spinopelvic fixation for ASD patients with long fusion is controversial. METHODS A comprehensive literature search was performed without time restriction according to the guidelines from the Cochrane Collaboration in May 2020 using PubMed, EMBASE, and the Cochrane Library. The comparison of the two types of fixation was evaluated by spinopelvic parameters, incidence rate of complications, rate of revision, and clinical outcomes at the last follow-up. RESULTS The literature search identified 422 records, of which eight studies were included for meta-analysis with a total of 439 patients. All the included studies provided level III evidence. There was no significant difference in the sagittal vertical axis, pelvic incidence, the proximal junctional kyphosis rates, the pseudarthrosis rates, the revision rates, and the clinical outcomes at the last follow-up between those who receive sacrum fixation and sacropelvic fixation. Nevertheless, greater lumbar lordosis (LL) (weighted mean difference [WMD], 4.15; 95% confidence interval [CI] 2.46-5.84, P

Objective: Hetertopic ossiofication (HO) was considered one of the main adverse events following lumbar decompression and could negatively affect these patients' daily activity. However, there is still a lack of evidence to assess the association between the incidence of HO at surgical segment and clinical outcomes following the implantation of a Coflex™ device. The objective of this study is determine the association between the incidence of HO and clinical outcomes following implantation of a Coflex™ device based on X-ray imaging. Methodology: One hundred sixty-nine consecutive patients who underwent decompression and implantation of a Coflex™ device from December 2007 to January 2014 were studied. A logistic regression analysis was used to analyze complications and development of HO. Spearman's rank correlation coefficient was used to analyze the correlation between clinical results and the incidence of HO based on X-ray imaging. Results: All patients showed improvement from baseline in clinical outcomes at all time points up to 5 years post-operation (all p = 0.000). Preoperative range of motion (ROM) of operated segment had a positive relationship with the incidence of HO (r = 0.194, p = 0.012). No correlation exists between the incidence of HO and clinical outcomes. The odds ratio (OR) for development of complications in patients with Pfirrmann disc degeneration classification grades III and IV compared to those with grades 0, I and II was 3.003 (p = 0.005, 95% confidence interval, 1.621–34.195). In addition, the OR for the incidence of HO in the large ROM of the surgical segment compared to that in the normal/small ROM segment was 21.670 (p = 0.001, 95% confidence interval, 21.137–22.280). Conclusions: Our findings provide evidence that high Pfirrmann disc degenerative classification grades and a large ROM of the surgical segment were the main risk factors for complications and development of HO, respectively.

Aims The aim of this study was to use diffusion tensor imaging (DTI) to investigate changes in diffusion metrics in patients with cervical spondylotic myelopathy (CSM) up to five years after decompressive surgery. We correlated these changes with clinical outcomes as scored by the Modified Japanese Orthopedic Association (mJOA) method, Neck Disability Index (NDI), and Visual Analogue Scale (VAS). Methods We used multi-shot, high-resolution, diffusion tensor imaging (ms-DTI) in patients with cervical spondylotic myelopathy (CSM) to investigate the change in diffusion metrics and clinical outcomes up to five years after anterior cervical interbody discectomy and fusion (ACDF). High signal intensity was identified on T2-weighted imaging, along with DTI metrics such as fractional anisotropy (FA). MJOA, NDI, and VAS scores were also collected and compared at each follow-up point. Spearman correlations identified correspondence between FA and clinical outcome scores. Results Significant differences in mJOA scores and FA values were found between preoperative and postoperative timepoints up to two years after surgery. FA at the level of maximum cord compression (MCL) preoperatively was significantly correlated with the preoperative mJOA score. FA postoperatively was also significantly correlated with the postoperative mJOA score. There was no statistical relationship between NDI and mJOA or VAS. Conclusion ms-DTI can detect microstructural changes in affected cord segments and reflect functional improvement. Both FA values and mJOA scores showed maximum recovery two years after surgery. The DTI metrics are significantly associated with pre- and postoperative mJOA scores. DTI metrics are a more sensitive, timely, and quantifiable surrogate for evaluating patients with CSM and a potential quantifiable biomarker for spinal cord dysfunction. Cite this article: Bone Joint J 2020;102-B(9):1210–1218.

The incidence of distraction spinal cord injury (DSCI), which results from spinal cord ischemia due to vascular compromise and spinal cord tract disturbances, remains high. Furthermore, because no ideal animal model that mimics DSCI in clinical settings is available thus far, the related molecular mechanisms underlying DSCI remain unclear. Thus, this study aimed to establish a porcine model of DSCI and investigate the neuroinflammation and apoptosis mechanisms in these pigs. Before surgery, all pigs were randomly divided into three groups: sham group, osteotomy surgery only; the incomplete distraction spinal cord injury (IDSCI) and complete distraction spinal cord injury (CDSCI) group, osteotomy plus DSCI surgery with a motor-evoked potential (MEP) amplitude decreased by approximately 75% and 100%, respectively. After surgery, modified Tarlov scoring and MRC muscle strength scoring were used to evaluate neurologic function in each group. We observed the distracted spinal cord using MRI, and then all pigs were sacrificed. Inflammatory cytokine levels in the spinal cord and cerebrospinal fluid (CSF) were also analyzed. We used immunofluorescence staining to assess the neuronal and microglial structure and function and astrocyte hyperplasia in the central DSCI lesions (T15). Western blotting was used to determine the expression of apoptosis-related proteins. Results showed that the modified Tarlov scoring and muscle strength decreased significantly in the two DSCI groups. T2-MRI showed a relative enhancement at the center of the DSCI lesions. H&E and Lxol fast blue staining revealed that spinal cord distraction destroyed the normal structure of spinal cord tissues and nerve fiber tracts, exacerbating inflammatory cell infiltration, hyperemia, and edema. The IL-1β, IL-6, and TNF-α levels increased in the spinal cord and CSF following DSCI. Immunofluorescence staining results indicated the GFAP, Iba-1 expression increased following DSCI, whereas the NeuN expression reduced. Moreover, DSCI promoted the protein expression of P53, Bcl-2-associated X protein (Bax), and Caspase-3 in the spinal cord tissues, whereas it reduced the Bcl-2 expression. This study successfully established a porcine DSCI model that closely mimics DSCI in clinical settings, and clarified the mechanisms underlying DSCI-associated neuroinflammation and apoptosis; thus, our findings highlight potential DSCI-treatment strategies for further establishing suitable drug therapies.

We sought to assess the elasticity change of the paravertebral fascia and muscle in adolescent idiopathic scoliosis patients with Lenke Type 1, 2, or 3 curves after posterior selective fusion surgery.The shear wave elasticity imaging system was used to assess the elasticity of the thoracic paravertebral muscles and fascia both on the concave and convex sides. Three regions of interest, including the apex, upper end, and lower end of the main curve, were tested.Ten female patients, with an average age of 16.6 ± 2.7 years old, were included. The average post-operation follow-up period was 9.0 ± 2.4 months. The Cobb angle was significantly corrected from 63.6 ± 12.0° to 10.7 ± 5.4° (p 0.05). The length of the trunk increased from 40.4 ± 2.5 cm to 46.0 ± 2.8 cm (p 0.05). The elasticity of deep fascia didn't show a significant change post-operation (p 0.05). The elasticity of the paravertebral muscle on the concave side had a significant increase at the final follow-up (p 0.05). The elasticity of the paravertebral muscle on the convex side also increased at the upper end (p 0.05). The elasticity asymmetry of the deep fascia decreased, but the elasticity asymmetry of the paravertebral muscle increased at the upper end of the curve (p 0.05).The paravertebral muscle on the concave side is stiffer after surgery. Elastic asymmetry of paravertebral muscle increased and elastic asymmetry of the deep fascia decreased at the upper end of the curvature. Further study is needed to elucidate the mechanism by which the paravertebral soft tissue responds after surgery.

Objective To compare the safety and accuracy of cortical bone trajectory screw placement between the robot-assisted and fluoroscopy-assisted approaches. Methods This retrospective study was conducted between November 2018 and June 2020, including 81 patients who underwent cortical bone trajectory (CBT) surgery for degenerative lumbar spine disease. CBT was performed by the same team of experienced surgeons. The patients were randomly divided into two groups—the fluoroscopy-assisted group (FA, 44 patients) and the robot-assisted group (RA, 37 patients). Robots for orthopedic surgery were used in the robot-assisted group, whereas conventional fluoroscopy-guided screw placement was used in the fluoroscopy-assisted group. The accuracy of screw placement and rate of superior facet joint violation were assessed using postoperative computed tomography (CT). The time of single screw placement, intraoperative blood loss, and radiation exposure to the surgical team were also recorded. The χ2 test and Student’s t-test were used to analyze the significance of the variables (P Results A total of 376 screws were inserted in 81 patients, including 172 screws in the robot-assisted group and 204 pedicle screws in the fluoroscopy-assisted group. Screw placement accuracy was higher in the RA group (160, 93%) than in the FA group (169, 83%) (P = 0.003). The RA group had a lower violation of the superior facet joint than the FA group. The number of screws reaching grade 0 in the RA group (58, 78%) was more than that in the FA group (56, 64%) (P = 0.041). Screw placement time was longer in the FA group (7.25 ± 0.84 min) than in the RA group (5.58 ± 1.22 min, P P = 0.313). The radiation time of the FA group (0.43 ± 0.07 min) was longer than the RA group (0.37 ± 0.10 min, P = 0.001). Furthermore, the overall learning curve tended to decrease. Conclusions Robot-assisted screw placement improves screw placement accuracy, shortens screw placement time, effectively improves surgical safety and efficiency, and reduces radiation exposure to the surgical team. In addition, the learning curve of robot-assisted screw placement is smooth and easy to operate.

BackgroundInflammatory processes exacerbated by IL-1β are believed to be key mediators of disc degeneration and low back pain. However, the underlying mechanism remains unclear. We performed a bioinformatics analysis to identify the key genes that were differentially expressed between degenerative intervertebral disc cells with and without exposure to interleukin (IL)-1β, and explore the related signaling pathways and interaction networks.MethodsThe microarray data were downloaded from the Gene Expression Omnibus (GSE 27494). Then, analyses of the gene ontology, signaling pathways, and interaction networks for the differentially expressed genes (DEGs) were conducted using tools including the Database for Annotation, Visualization, and Integrated Discovery (DAVID), Metascape, Gene Set Enrichment Analysis (GSEA), Search Tool for the Retrieval of Interacting Genes (STRING), Cytoscape, the Venn method, and packages of the R computing language.ResultsA total of 260 DEGs were identified, including 161 upregulated genes and 99 down-regulated genes. Gene Ontology (GO) annotation analysis showed that these DEGs were mainly associated with the extracellular region, chemotaxis, taxis, cytokine activity, and cytokine receptor binding. A Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analysis showed that these DEGs were mainly involved in the interactions of cytokine-cytokine receptor interaction, rheumatoid arthritis, tumor necrosis factor (TNF) signaling pathway, salmonella infection, and chemokine signaling pathway. The interaction network analysis indicated that 10 hub genes, including CXCL8, CXCL1, CCL20, CXCL2, CXCL5, CXCL3, CXCL6, C3, PF4, and GPER1 may play key roles in intervertebral disc degeneration.ConclusionsBioinformatic analysis showed that CXCL8 and other 9 key genes may play a role in the development of disc degeneration induced by inflammatory reactions, and can be used to identify the potential therapeutic target genes.

Study Design: Retrospective case-control study. Objective: We aimed to evaluate the value of 3-dimensional printing (3DP) spine model in the surgical treatment of severe spinal deformity since the prosperous development of 3DP technology. Methods: Severe scoliosis or hyper-kyphosis patients underwent posterior fixation and fusion surgery using the 3DP spine models were reviewed (3DP group). Spinal deformity surgeries operated by free-hand screw implantation during the same period were selected as the control group after propensity score matching (PSM). The correction rate, pedicle screw accuracy, and complications were analyzed. Class A and B screws were defined as accurate according to Gertzbein and Robbins criteria. Results: 35 patients were enrolled in the 3DP group and 35 matched cases were included in the control group. The perioperative baseline data and deformity correction rate were similar between both groups ( P > .05). However, the operation time and blood loss were significantly less in the 3DP group (296.14 ± 66.18 min vs. 329.43 ± 67.16 min, 711.43 ± 552.28 mL vs. 1322.29 ± 828.23 mL, P < .05). More three-column osteotomies (Grade 3-6) were performed in the 3DP group (30/35, 85.7% vs. 21/35, 60.0%. P = .016). The screw placement accuracy was significantly higher in the 3DP group (422/582, 72.51% vs. 397/575, 69.04%. P = .024). The screw misplacement related complication rate was significantly higher in the free-hand group (6/35 vs. 1/35, P = .046). Conclusions: The study provided solid evidence that 3DP spine models can enhance surgeons’ confidence in performing higher grade osteotomies and improve the safety and efficiency in severe spine deformity correction surgery. 3D printing technology has a good prospect in spinal deformity surgery.

Background To evaluate the incidence and risk factors associated with unintended return to the operating room in adult spinal deformity after spinal deformity corrective surgery. Methods Retrospect of 141 adult spinal deformity patients in a single institution between January 2017 and December 2019. Inclusion criteria enrolled 18 to 80 years old patients who diagnosed with congenital/idiopathic/syndromic/acquired spinal deformity underwent posterior corrective spinal surgery. The surgical details and complications were recorded. The rate of unintended return to the operating room (UIROR) during hospitalization was examined, and the risk factors of unintended return to the operating room were investigated via multivariate analysis. Results This is a retrospective study. One hundred and forty-one patients who underwent spinal deformity surgery with a mean age of 31.8 years (range 18-69 years) were studied. The rate of unintended return to the operating room was 10.64% (15/141). Two of 15 patients had twice unintended surgery during hospitalization (13.33%). The most principal complication was neurologic deficit (73.3%); six of 15 postoperative present implants deviation causes severe lower limbs radiating pain (40%). The multivariate analysis shows higher apical vertebral rotation (AVR>grade II, odds ratio [OR] = 9.362; 95% CI= 1.930-45.420; P= .006), obesity (OR = 11.448; 95% CI= 1.320-99.263; P= .027), and previous neurological symptom (OR = 7.358; 95% CI= 1.798-30.108; P= .006) were independent predictors of unintended return to the operating room. Conclusion Postoperative neurologic deficit and short-term implant malposition are essential causes of unintended return to the operating room in adult spinal deformity patients. Preoperative factors such as higher AVR (> grade II), obesity, and previous neurological symptom may significantly increase the risk of morbidity in UIROR. Spine surgeons should be alert to these risk factors and require adequate preoperative evaluations to reduce the incidence of unintended return to the operating room.

Objectives The aim of this study was to identify perioperative risk factors of pulmonary complications (PC) after posterior instrumentation and fusion (PIF) for non-degenerative scoliosis and devise a predictive scoring system that could be used by spine surgeons to predict the level of risk requiring advanced measures. Patients and methods A retrospective review was performed of 703 patients who underwent PIF at our center between January 2010 and January 2018. Preoperative, peri-operative, demographic data, surgical methods, and radiographic parameters were extracted to identify the predictors of PC, and a predictive scoring system was created using multiple logistic regression and receiver operator characteristic (ROC). Results There were statistically significant differences in revision surgery, preoperative pulmonary disease, Cobb angle and thoracoplasty between the patients who suffered from PC as compared to those who did not. The predictive scoring system included four dimensions. The area under the ROC curve for the system was 0.82 for PC after PIF at the optimal cut-off point, and the sensitivity was 79.2%, which demonstrated good diagnostic accuracy. Conclusion We identified a significant relationship between perioperative parameters (revision surgery, preoperative pulmonary disease, Cobb angle and thoracoplasty) and PC after PIF for non-degenerative scoliosis and created a predictive scoring system that can be used to prepare measures to manage PC after PIF. The system was proven to be reliable in this study.

Background: Inflammatory processes exacerbated by IL-1β are believed to be key mediators of disc degeneration and low back pain. However, the underlying mechanism remains unclear. We performed a bioinformatics analysis to identify the key genes that were differentially expressed between degenerative intervertebral disc cells with and without exposure to interleukin (IL)-1β, and explore the related signaling pathways and interaction networks.Methods: The microarray data were downloaded from the Gene Expression Omnibus (GSE 27494). Then, analyses of the gene ontology, signaling pathways, and interaction networks for the differentially expressed genes (DEGs) were conducted using tools including the Database for Annotation, Visualization, and Integrated Discovery (DAVID), Metascape, Gene Set Enrichment Analysis (GSEA),Search Tool for the Retrieval of Interacting Genes (STRING), Cytoscape, the Venn method, and packages of the R computing language.Results: A total of 260 DEGs were identified, including 161 upregulated genes and 99 down-regulated genes. Gene Ontology (GO) annotation analysis showed that these DEGs were mainly associated with the extracellular region, chemotaxis, taxis, cytokine activity, and cytokine receptor binding. A Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analysis showed that these DEGs were mainly involved in the interactions of cytokine-cytokine receptor interaction, rheumatoid arthritis, tumor necrosis factor (TNF) signaling pathway, salmonella infection, and chemokine signaling pathway. The interaction network analysis indicated that 10 hub genes, including CXCL8, CXCL1, CCL20, CXCL2, CXCL5, CXCL3, CXCL6, C3, PF4, and GPER1 may play key roles in intervertebral disc degeneration.Conclusions: Bioinformatic analysis showed that CXCL8 and other 9 key genes may play a role in the development of disc degeneration induced by inflammatory reactions, and can be used to identify the potential therapeutic target genes.

ObjectiveTo characterize the safety and effectiveness during one surgeon’s initial phases of performing a Midline lumbar fusion by freehand technique based on perioperative parameters.MethodsThe first 90 consecutive patients underwent single level MIDLF, utilized a consistent technique, performed by one surgeon were retrospectively studied. A piecewise regression analysis was performed to evaluate the operation duration based on case number, and to estimate the breakpoint. The early learning period and the late steady phase was divided according to the case number of the breakpoint. Perioperative parameters and clinical data of 2 groups were compared then to elucidate if improvement in operative duration was accompanied by better patient prognosis.ResultsThe inflectional asymptote of the surgeon’s learning curve for MIDLF was achieved at the 40th case. The demographics parameters were similar between the early group of 40 patients and the latter 50. Average surgical time, intraoperative blood loss, length of incision, duration of drainage, postoperative drainage and post-operative hospitalization were significantly less in the late cohort (p.05), and lateral cortical breach was observed in 35/360 cases (24 vs.11, P.05). The overall complication incidence decreased alone with the learning curve, and statistical difference was achieved. Furthermore, there was no difference in clinical improvement between the two groups.ConclusionsOur result indicated that technical proficiency in MIDLF was achieved after 40 surgeries. And it is effective to significantly improve the patients’ functional status and relief the pain during one surgeon’s learning process of MIDLF in the treatment of lumbar degenerative disease, even in the initial phase. As the surgeon gains surgical proficiency and familiarity with MIDLF procedure, potential complications could be minimized. Furthermore, our results provided evidence to the excellent performance as an alternative option to traditional pedicle screw fixation.

STUDY DESIGN This was a retrospective observational study. OBJECTIVE We aimed to characterize the feasibility of assessing the accuracy of cortical bone trajectory (CBT) screw placement in midline lumbar interbody fusion using a traditional pedicle screw insertion accuracy evaluation system based on computed tomography (CT). SUMMARY OF BACKGROUND DATA Since Santoni and colleagues proposed CBT as an alternative approach for the treatment of lumbar degenerative disease, CBT has been biomechanically and clinically investigated in detail. The reported misplacement rate was 0%-12.5%. Therefore, these cortical screws may result in severe complications, such as nerve root, vascular, and spinal cord injuries. However, to the best of our knowledge, the accuracy of the current assessment system of cortical bone screw placement has not been described clearly. MATERIALS AND METHODS Overall, 342 cortical screws of 69 consecutive patients with lumbar degenerative disease who underwent midline lumbar interbody fusion surgery in one surgeon's initial phase were examined retrospectively. A comprehensive and detailed pedicle screw accuracy classification and grading system was introduced in our study, including 5 types of misplacement: (1) medial and (2) lateral cortical bone perforation (MCP and LCP) of the corresponding pedicle, (3) anterior cortical bone perforation of the vertebral body, (4) endplate perforation, and (5) foraminal perforation (FP). The degree of interobserver and intraobserver agreement with regard to the screw positions based on CT were used as indicators of the reliability of the modified classification system. All patients were retrospectively assessed for screw placement-related complications throughout the entire treatment course to evaluate the relationship between the procedure adequacy and neurological symptoms. RESULTS The interobserver and intraobserver agreements were substantial-to-almost perfect (κ=0.78 and 0.88, respectively) in distinguishing the acceptable-placed pedicle screws from those with partial or complete cortical perforation. In the MCP and LCP-the most common types of misplacement-the interobserver agreement was substantial (κ=0.70 and 0.76, respectively), and the intraobserver agreement was almost perfect (κ=0.85 and 0.89, respectively). In total, there are 7 (2.05%) MCP and 65 (19.01%) LCP screws. The screw placement-related complication rate is significantly higher in the MCP and FP groups than that in the LCP group. CONCLUSIONS Our study demonstrated that using a pedicle screw classification and grading system based on CT to assess the accuracy of CBT screw placement is feasible and practical. MCP and FP screws are more likely to cause neurological deficits with statistical significance, especially grade 2 MCP. We recommend inexperienced surgeons choose a lateral trajectory rather than a medial one if they cannot ensure accurate screw insertion. LEVEL OF EVIDENCE Level III.

Objective To evaluate the position of the aorta relative to the spine and the risk of aortic injury during correction surgery in patients with idiopathic severe and rigid scoliosis (main curve Cobb angle >90° and flexibility Methods Twenty-seven patients with severe right thoracic/thoracolumbar scoliosis were recruited. The entry point–aorta distance (EAD), the left pedicle–aorta angle (α), the left aorta angle (β), and the vertebral rotation angle (γ) were measured from 4 vertebrae above (A4) to 4 below (B4) the apical vertebra (Apex) to quantify the spatial relationship between aorta and spine. We simulated the pedicle screw misplacement with variable direction error, length, and diameter to analyze the potential risk of aortic injury. Results The aorta shifted laterally and posteriorly as it descended from A4 and moved back medially and anteriorly from Apex. The potential risk of aortic injury increased with the augment of direction error and/or length of the screw, but the tendency was not significant with the augment of diameter. The risk peaked at A4, A3, and B2, when the screw length was 40 mm and diameter was 5.0 mm, and the direction error was 30°, whereas the risk was lowest at the apical level 14.3% (0%–40.7%) in any scenarios. Conclusions In patients with severe and rigid scoliosis, the aorta shifted more laterally and posteriorly, and the injury risk was lower at the apical level, compared with moderate scoliosis. Most potential risks can be minimized by careful preoperative planning and the assistance of intraoperative navigation or robotics.

To investigate the correlation between fatty infiltration in the multifidus muscle related to the involved nerve root and structural parameters associated with stenosis in patients with degenerative lumbar spinal stenosis (DLSS).Sixty-four patients with single-segment DLSS at L4-5 were retrospectively enrolled. The fatty infiltration rate (FIR) of the multifidus muscle at L5-S1, lumbar lordosis and the cross-sectional area (CSA) of the structural parameters at L4-5, such as dural sac, disc bulge, ligamentum flava and vertebral body of L5 were measured on magnetic resonance images using ImageJ software. All enrolled patients were divided into an FIR 25 % group and an FIR ≥ 25 % group according to the FIR of the multifidus muscle at L5-S1. The propensity scores matching and adjustment of potential covariates were performed to reduce the confounding bias between the two groups.Lumbar lordosis in the FIR ≥ 25 % group was significantly lower than that in the FIR＜25 % group in both cohorts. The mean differences in lumbar lordosis of 14.16 degrees between the two groups in the complete cohort and of 14.23 degrees in the matched cohort remained significant after adjustment. The disc bulge CSA/ vertebral body CSA in the FIR ≥ 25 % group was greater than that in the FIR＜25 % group in both cohorts. The mean differences in the disc bulge CSA/ vertebral body CSA between the two groups of 0.67 in the complete cohort and 0.96 in the matched cohort were statistically significant after adjustment. There was no significant difference in the dural sac CSA/ vertebral body CSA and ligamentum flava CSA/ vertebral body CSA between the two groups in either cohort regardless of adjustment. Logistic regression analysis for FIR ≥ 25 % in the multifidus muscle at L5-S1 exhibited that the disc bulge CSA/ vertebral body CSA were independent risk factors with odds ratio (OR) of 8.52, while lumbar lordosis were independent protective factors (OR = 0.72).The disc bulge at the stenosis segment and lumbar lordosis reduction may be correlated with fatty infiltration in the multifidus muscles at L5-S1 in patients with L4-5 single-segment DLSS.

The multifidus muscle morphology and its relation to the function of patients with degenerative lumbar spinal stenosis (DLSS) remains unclear. This study aimed to investigate the multifidus muscle morphology in patients with DLSS and to determine its relations to the patients function. Sixty-two patients with single-segment DLSS at L4-5 and sixty control patients with non-spinal-derived low back pain were retrospectively enrolled and further matched based on propensity scores. The Oswestry Disability Index (ODI) and bodily pain using the Short-Form Health Survey were evaluated. The cross-sectional area (CSA), CSA of fatty free (CSAF), and fatty infiltration rate [FIR; i.e., (1- CSAF/CSA) × 100%] of the multifidus muscle were measured on magnetic resonance images using ImageJ software. Adjustment for confounders was performed using generalized linear models. The FIR at L5-S1 in controls was statistically significant but slightly less than the DLSS group. The between-groups difference was 5% (p 0.001), and 2.8% (p = 0.036) in the complete and matching cohorts, respectively, after adjustment. Statistically significant differences were not observed in other multifidus muscle parameters between the groups. FIR 20% at L5-S1 was independently associated with ODI ≥ 41 in patients with DLSS [Retaining demography as control block or not, Odds ratio (OR) = 8.4, p = 0.023; OR = 12.3, p = 0.030]. The multifidus muscle at L5-S1 demonstrated slightly greater fatty infiltration in patients with L4-5 single-segment DLSS than controls. Significant fatty infiltration in the multifidus muscle at L5-S1 may be correlated with poor function in patients with L4-5 single-segment DLSS.

To determine whether fat infiltration in the multifidus muscle would predict surgical prognosis in patients with degenerative lumbar spinal stenosis (DLSS).This ambispective cohort study enrolled 118 consecutive patients undergoing surgery for L4-5 single-segment DLSS. Fat infiltration rate (FIR) on magnetic resonance images of the multifidus muscle at L5-S1 were measured using ImageJ software. The enrolled patients were divided into FIR25% and FIR ≥25% groups according to their FIR of the multifidus muscle at L5-S1. The 2 groups of patients who finished follow-up were further matched for the baseline covariates based on propensity scores. Patients' reported outcomes including the visual analog scale score for back pain and leg pain, and the Oswestry Disability Index (ODI) score were compared between groups at follow-up and further adjusted using generalized linear models.Patients in the FIR25% group showed statistically significantly greater reduction in ODI at 6 and 18 months after surgery than did patients in the FIR ≥25% group in either cohort regardless of adjustment; however, the 2-point between-group difference was smaller than the predefined minimum clinically important difference. In addition, more patients in the FIR25% group achieved clinically significant improvement in ODI than those in the FIR ≥25% group in either complete cohort or matching cohort (63.8% vs. 21.1%, P0.001; 70.3% vs. 24.1%, P 0.001, respectively) before and after adjustment (63.3% vs. 27.8%, P0.001; 69.1% vs. 31.0%, P0.001, respectively).Fat infiltration in multifidus muscle at L5-S1 could be a potential predictor of functional improvement after surgery in patients with L4-5 single-segment DLSS.

The aim of this study was to evaluate the prevalence and risk factors for postoperative pulmonary complications (PPC) after posterior instrumentation and fusion (PIF) in patients with non-degenerative scoliosis.We retrospectively evaluated 703 patients (224 males, 479 females) diagnosed with non-degenerative scoliosis who underwent PIF in our center from January 2010 to January 2018. Preoperative, perioperative, demographic data, surgical methods and radiographic parameters were extracted and analyzed to identify risk factors for PPC.The mean age of the patients was 20.8 ± 9.0 years with the following diagnoses: congenital scoliosis (287/703, 40.8%), idiopathic scoliosis (281/703, 40.0%), neuromuscular scoliosis (103/703, 14.7%) and syndromic scoliosis (32/703, 4.5%). PPC manifested in 82 patients (11.7%) including pleural effusion (39/82, 47.6%), pneumonia (33/82, 40.2%), pneumothorax (3/82, 3.7%), respiratory failure (3/82, 3.7%), hemothorax (2/82, 2.4%), pulmonary edema (1/82, 1.2%) and pulmonary embolism (1/82, 1.2%). Multifactorial regression analysis confirmed that revision surgery [odds ratio (OR) = 2.320, P = 0.030], preoperative respiratory disease (OR = 14.286, P 0.001), preoperative Cobb angle of main curve 75° (OR = 1.701, P = 0.046) and thoracoplasty (OR = 4.098 P 0.001) were risk factors for PPC after PIF in patients with non-degenerative scoliosis.A prevalence of 11.7% PPC was observed after PIF. Risk factors were preoperative Cobb angle of main curve 75°, preoperative respiratory disease, revision surgery and thoracoplasty. Surgeons should recognize and pay attention to these risk factors and take appropriate preventive measures to prevent severe pulmonary complications. These slides can be retrieved under Electronic Supplementary Material.