Ipsilateral Fixation and Reconstruction of the Cervical Spine after Resection of a Dumbbell Tumor Via a Unilateral Posterior Approach: A Case Report and Biomechanical Study.

OBJECTIVE: There is lack of an internal fixation following resection of a dumbbell tumor by hemi-laminectomy and facetectomy that achieves adequate stability with less trauma. Unilateral fixation and reconstruction (unilateral pedicle screw and contralateral lamina screw fixation combined with lateral mass reconstruction, UPS + CLS + LM) may be an ideal technique to address this problem. A biomechanical comparison and a case report were designed to evaluate its spinal stability and clinical effect. METHODS: Seven fresh-frozen human subcervical specimens were used for the biomechanical testing. The conditions tested were: (1) intact; (2) injured (single-level hemi-laminectomy and facetectomy); (3) unilateral pedicle screw (UPS) fixation; (4) UPS fixation combined with lateral mass (LM) reconstruction (UPS + LM); (5) UPS fixation and contralateral lamina screw fixation (UPS + CLS); (6) UPS + CLS + LM; (7) UPS fixation and contralateral transarticular screw fixation (UPS + CTAS); (8) bilateral pedicle screw (BPS) fixation. Range of motion (ROM) and neutral zone (NZ) were obtained at C5-C7 segment under eight conditions. In addition, we report the case of a patient with a C7-T1 dumbbell tumor that was treated by UPS + CLS + LM technique. RESULTS: Except left/right lateral bending and right axial rotation (all, p < 0.05), ROM of UPS + CLS + LM condition in other directions was similar to that of BPS condition (all, p > 0.05). There was no significant difference between UPS + CLS + LM and the UPS + CTAS condition in other directions of ROM (all, p > 0.05), except in left/right axial rotation (both, p < 0.05). Compared to UPS + CLS condition, left/right lateral bending ROM of UPS + CLS + LM condition were significantly reduced (both, p < 0.05). UPS + CLS + LM condition significantly reduced ROM in all directions compared to UPS and UPS + LM condition (all, p < 0.05). Similarly, except lateral bending (p < 0.05), there was no difference in NZ in other directions between UPS + CLS + LM and BPS condition (both, p > 0.05). There was no significant difference between UPS + CLS + LM and UPS + CTAS condition in NZ in all directions (all, p > 0.05). Axial rotation NZ of UPS + CLS + LM condition was significantly reduced compared to UPS + CLS condition (p < 0.05). Compared to UPS and UPS + LM condition, NZ of UPS + CLS + LM condition was significantly reduced in all directions (all, p < 0.05). The patient's imaging examination at 3 months postoperatively indicated that the internal fixation did not move and the graft bone was seen with fusion. CONCLUSION: After resection of a dumbbell tumor in the cervical spine, UPS + CLS + LM technique is a reliable internal fixation method to provide sufficient immediate stability and promote postoperative bone fusion.

Bioinformatics analysis identified apolipoprotein E as a hub gene regulating neuroinflammation in macrophages and microglia following spinal cord injury.

Macrophages and microglia play important roles in chronic neuroinflammation following spinal cord injury (SCI). Although macrophages and microglia have similar functions, their phagocytic and homeostatic abilities differ. It is difficult to distinguish between these two populations in vivo, but single-cell analysis can improve our understanding of their identity and heterogeneity. We conducted bioinformatics analysis of the single-cell RNA sequencing dataset GSE159638, identifying apolipoprotein E (APOE) as a hub gene in both macrophages and microglia in the subacute and chronic phases of SCI. We then validated these transcriptomic changes in a mouse model of cervical spinal cord hemi-contusion and observed myelin uptake, lipid droplets, and lysosome accumulation in macrophages and microglia following SCI. Finally, we observed that knocking out APOE aggravated neurological dysfunction, increased neuroinflammation, and exacerbated the loss of white matter. Targeting APOE and the related cholesterol efflux represents a promising strategy for reducing neuroinflammation and promoting recovery following SCI.

Medial Buttress Plate and Allograft Bone-Assisted Cannulated Screw Fixation for Unstable Femoral Neck Fracture with Posteromedial Comminution: A Retrospective Controlled Study.

OBJECTIVE: To investigate the outcomes of open reduction and internal fixation combined with medial buttress plate (MBP) and allograft bone-assisted cannulated screw (CS) fixation for patients with unstable femoral neck fracture with comminuted posteromedial cortex. METHODS: In a retrospective study of patients operated on for unstable femoral neck fractures with comminuted posteromedial cortex from March 2016 to August 2020, the clinical and radiographic outcomes of 48 patients treated with CS + MBP were compared with the outcomes of 54 patients treated with CS only. All patients in the CS + MBP group were fixed by three CS and MBP (one-third tubular plates or reconstructive plates) with bone allografts. The surgery-related outcomes and complications were evaluated, including operative time, blood loss, union time, femoral head necrosis, femoral neck shortening, and other complications after the operation. The Harris score was evaluated at 12 months after the operation. RESULTS: All patients were followed up for 12-40 months. The average age of patients in the CS-only group (54 cases, 22 females) and CS + MBP group (48 cases, 20 females) was 48.46 ± 7.26 and 48.73 ± 6.38 years, respectively. More intraoperative blood loss was observed in the CS + MBP group than that of patients in CS-only group (153.45 ± 64.27 vs 21.86 ± 18.19 ml, t = 4.058, P = 0.015). The average operative time for patients in the CS + MBP group (75.35 ± 27.67 min) was almost double than that of patients in the CS-only group (36.87 ± 15.39 min) (t = 2.455, P < 0.001). The Garden alignment index of patients treated by CS + MBP from type I to type IV was 79%, 19%, 2%, and 0%, respectively. On the contrary, they were 31%, 43%, 24% and 2% for those in the CS-only group, respectively. The average healing times for the CS-only and CS + MBP groups were 4.34 ± 1.46 and 3.65 ± 1.85 months (t = 1.650, P = 0.102), respectively. Femoral neck shortening was better in the CS + MBP group (1.40 ± 1.73 mm, 9/19) than that in the CS-only group (4.33 ± 3.32 mm, 24/44). Significantly higher hip function was found in the CS + MBP group (85.60 ± 4.36 vs 82.47 ± 6.33, t = 1.899, P = 0.06). There was no statistical difference between femoral head necrosis (4% vs 11%, χ2  = 1.695, P = 0.193) and nonunion (6% vs 9%, χ2  = 0.318, P = 0.719). CONCLUSION: For unstable femoral neck fractures with comminuted posteromedial cortex, additional MBP combined with bone allografts showed better reduction quality and neck length control than CS fixation only, with longer operative time and more blood loss.

Cervical Alignment of Patients with Basilar Invagination: A Radiological Study.

OBJECTIVE: To investigate the cervical alignment and the relative range of motion (ROM) in patients with basilar invagination (BI). METHODS: A total of 40 BI cases (38.1 years old ± 17.9 years old, 19 male and 21 female) and 80 asymptomatic individuals (33.8 years old ± 10.8 years old, 40 male and 40 female) were included. The Skull-C2 /Skull-BV, Skull-C7 , C2 -C7 /BV-C7 wall angles, C0 -C2 /C0 -BV, C0 -C7 , C1 -C7 , and C2 -C7 /BV-C7 angles were measured in dynamic X-ray images (including neutral, extension, and flexion positions). Correlation between the upper and lower cervical curvatures were analyzed. The total, extension, and flexion ROMs of these angles were calculated, respectively. RESULTS: The BI patients had a smaller C0 -C2 /C0 -BV angle (18.2° ± 16.4° vs 30.9° ± 9.3°), but larger C2 -C7 /BV-C7 (32.2° ± 16.1° vs 19.4° ± 10.6°) and C2 -C7 /BV-C7 wall angles (37.8° ± 17.2° vs 23.6° ± 10.2°) than the control group in neutral position. The upper and lower curvatures correlated negatively in neutral (r = -0.371), extension (r = -0.429), and flexion (r = -0.648) positions among BI patients, as well as in extension position (r = -0.317) among control group. The BI patients presented smaller total ROMs in Skull-C2 /Skull-BV (12.3° ± 16.6° vs 19.7° ± 10.9°), C0 -C2 /C0 -BV (8.1° ± 11.1° vs 17.6° ± 10.5°), and C0 -C7 angles (57.8° ± 14.2° vs 78.3° ± 17.9°), but a larger total ROM in C2 -C7 /BV-C7 wall angle (52.8° ± 13.9° vs 27.0° ± 16.1°) than the control group. The BI patients also presented smaller extension ROMs in Skull-C2 /Skull-BV (6.9° ± 9.4° vs 12.5° ± 9.3°), Skull-C7 (24.5° ± 10.9° vs 30.7° ± 12.5°), and C0 -C2 /C0 -BV angles (4.4° ± 7.8° vs 9.9° ± 8.6°) than the control group. Moreover, the BI patients showed smaller absolute values of flexion ROMs in Skull-C2 /Skull-BV (-5.2° ± 9.4° vs -7.3° ± 8.0°), C0 -C2 /C0 -BV (-3.2° ± 8.8° vs -7.7° ± 8.7°), and C0 -C7 angles (-33.2° ± 13.0° vs -52.8° ± 19.2°), but a larger absolute value of flexion ROM in C2 -C7 /BV-C7 wall angle (-33.9° ± 14.8° vs -8.2° ± 15.1°). CONCLUSION: The cervical spine was stiffer in BI patients than the asymptomatic individuals, especially in the upper cervical curvature. The negative correlation between upper and lower cervical curvatures was more obvious in BI patients.

Genome-Wide Expression Difference of MicroRNAs in Basal Cell Carcinoma.

Distinct expression of the miRNAs has rarely been explored in basal cell carcinoma (BCC) of skin, and the regulatory role of miRNAs in BCC development remains quite opaque. Here, we collected control tissues from adjacent noncancerous skin (n = 15; control group) and tissues at tumor centers from patients with cheek BCC (n = 15; BCC group) using punch biopsies. After six small RNA sequencing- (sRNA-seq-) based miRNA expression profiles were generated for both BCC and controls, including three biological replicates, we conducted comparative analysis on the sRNA-seq dataset, discovering 181 differentially expressed miRNAs (DEMs) out of the 1,873 miRNAs in BCCs. In order to validate the sRNA-seq data, expression of 15 randomly selected DEMs was measured using the TaqMan probe-based quantitative real-time PCR. Functional analysis of predicted target genes of DEMs in BCCs shows that these miRNAs are primarily involved in various types of cancers, immune response, epithelial growth, and morphogenesis, as well as energy production and metabolism, indicating that BCC development is caused, at least in part, by changes in miRNA regulation for biological and disease processes. In particular, the "basal cell carcinoma pathways" were found to be enriched by predicted DEM targets, and regulatory relationships between DEMs and their targeted genes in this pathway were further uncovered. These results revealed the association between BCCs and abundant miRNA molecules that regulate target genes, functional modules, and signaling pathways in carcinogenesis.

Proteomics and bioinformatics reveal insights into neuroinflammation in the acute to subacute phases in rat models of spinal cord contusion injury.

Neuroinflammation is recognized as a hallmark of spinal cord injury (SCI). Although neuroinflammation is an important pathogenic factor that leads to secondary injuries after SCI, neuroprotective anti-inflammatory treatments remain ineffective in the management of SCI. Moreover, the molecular signatures involved in the pathophysiological changes that occur during the course of SCI remain ambiguous. The current study investigated the proteins and pathways involved in C5 spinal cord hemi-contusion injury using a rat model by means of 4-D label-free proteomic analysis. Furthermore, two Gene Expression Omnibus (GEO) transcriptomic datasets, Western blot assays, and immunofluorescent staining were used to validate the expression levels and localization of dysregulated proteins. The present study observed that the rat models of SCI were associated with the enrichment of proteins related to the complement and coagulation cascades, cholesterol metabolism, and lysosome pathway throughout the acute and subacute phases of injury. Intriguingly, the current study also observed that 75 genes were significantly altered in both the GEO datasets, including ANXA1, C1QC, CTSZ, GM2A, GPNMB, and PYCARD. Further temporal clustering analysis revealed that the continuously upregulated protein cluster was associated with immune response, lipid regulation, lysosome pathway, and myeloid cells. Additionally, five proteins were further validated by means of Western blot assays and the immunofluorescent staining showed that these proteins coexisted with the F4/80+ reactive microglia and infiltrating macrophages. In conclusion, the proteomic data pertaining to the current study indicate the notable proteins and pathways that may be novel therapeutic targets for the treatment of SCI.

A preliminary study of a novel robotic system for pedicle screw fixation: A randomised controlled trial.

BACKGROUND AND OBJECTIVE: Existing orthopaedic robotic systems are almost restricted to provide guidance for trajectory direction. In the present study, a novel spinal robotic system with automatic drilling power was introduced. The aim of this study is to evaluate the feasibility and safety in pedicle screw â€‹insertion of posterior lumbar interbody fusion assisted by this novel robotic system. METHODS AND MATERIALS: A randomised controlled trial was conducted for 17 participants who were required posterior lumbar interbody fusion process. Seven (3 M/4 F) were randomly assigned to the robot-assisted group (RA group), and the other ten (4 M/6 F) were assigned to the conventional technique group (FH group). A novel robotic system was used in the RA group. All measurements were based on postoperative computed tomography (CT) data. Accuracy of screw insertion was determined using the Gertzbein and Robbins Scale. Precision was measured by the entry point deviation distance and the trajectory rotation. Other variables included operation time, radiation time, length of stay, and screw-related complications. RESULT: A total of 82 pedicle screws were placed in the 17 participants. In the RA group, 90.6% of screws placed were Grade A, and 9.4% were Grade B. In the FH group, 78.0% of screws were Grade A, 20.0% were Grade B, and 2.0% were Grade C. No statistical difference was found in the operation time, radiation time per case, and length of stay between both groups. The radiation time per screw is significantly lower in the RA group. No screw-related complications or revision occurred in the present study. CONCLUSION: The outcome of screw accuracy of this robotic system was comparable with that of experienced surgeons, and no screw-related complication was found in the RA group during hospitalisation. In addition, radiation time per screw in the robotic group was significantly lower than that in the conventional group, which shows the potential to reduce radiation exposure of pedicle screw fixation assisted by this robotic system. TRANSLATIONAL POTENTIAL: Our study shows that pedicle screw fixation assisted by "Orthbot" system is accurate and safe. It is concluded that this novel robotic system offers a new option for internal implantation in spine surgery.

Cortical bone trajectory screws for the middle-upper thorax: An anatomico-radiological study.

To quantify the reference data concerning the morphometrics of the middle-upper thorax to guide the placement of cortical bone trajectory (CBT) screws.Eighty patients were studied on computed tomography (CT) scans. The reference anatomical parameters were measured. Next, 20 cadaveric specimens were implanted with CBT screws based on CT measurements. These specimens were then judged directly from the cadaveric vertebrae and X-ray.The maximum length of the trajectory, the maximum diameter, and the cephaled angle exhibited a slight increase trend while the transverse and sagittal angles of the pedicle tended to decrease from T3 to T8. We recommend that the width of CBT screw for middle-upper thoracic spine is 5.0 mm, the length is 25 to 35 mm. The cadaveric anatomical study revealed that 5/240 screws penetrated in the medial or lateral areas, 5/240 screws penetrated in the superior or inferior pedicle wall, and 2/240 screws did not fit into the superior endplate of the pedicle.The CBT screws are safe for the middle-upper thorax. This study provides a theoretical basis for clinical surgery.

[Effects of bioactive modification of poly-D,L-lactide acid scaffolds on the biological behaviors of the seed cells].

OBJECTIVE: To study the changes in the biological behavior of bone marrow mesenchymal stem cells (BMSCs) transfected with red fluorescent protein by lentivirus (RFP-BMSCs) seeded on in poly-D, L-lactide acid (PDLLA) scaffolds with bioactive modification by ammonia plasma and Gly-Arg-Gly-Asp-Ser (GRGDS) in vitro. METHODS: Circular sheets of PDLLA scaffolds (8 mm in diameter and 1 mm in thickness) were prepared and aminated with PDLLA (group A) or modified with the peptide conjugate A/PDLLA (group PA), with untreated PDLLA as the control (group P). The RFP-BMSCs were seeded on the scaffold materials and their proliferation and metabolic activity were detected using CyQuant NF and Alamar blue staining. The mineralization on the scaffolds was observed using calcein fluorescent dye under a fluorescent microscope. The adhesion and proliferation of RFP-BMSCs were observed by fluorescent microscope, and scanning electron microscope (SEM) was used to confirm the observed adhesion of the seed cells. RESULTS: The RFP-BMSCs seeded on the 3 scaffolds all showed proliferative activity at different time points after cell seeding, and the cell numbers decreased significantly in the order of PA>A>P (P<0.001). The cell number was significantly greater in group PA than in group A at all the time points except for days 10 (P=0.077) and 12 (P=0.491), and gradually became similar with the passage of time. The metabolic changes of the cells follow a similar pattern of cell proliferation. RFP-BMSCs showed more active proliferation in group A and group PA than in group P. On days 14 and 21, the intensity of green fluorescence decreased in the order of group PA, A and P. The RFP-BMSCs showed better adhesion in group PA than in group A, and the cells in group P appeared more scattered under scanning electron microscope. CONCLUSION: Bioactive modification of PDLLA by ammonia treatment and conjugation with GRGDS peptides may promotes the adhesion, proliferation, metabolism and mineralization of RFP-BMSCs seeded on PDLLA scaffolds.

[Studies on poly-D, L-lactide acid scaffolds modified by conjugation of bioactive peptides via ammonia plasma treatment].

OBJECTIVE: To study the feasibility of preparation of the poly-D, L-lactide acid (PDLLA) scaffolds treated by ammonia plasma and subsequent conjugation of Gly-Arg-Gly-Asp-Ser (GRGDS) peptides via amide linkage formation. METHODS: PDLLA scaffolds (8 mm diameter, 1 mm thickness) were prepared by solvent casting/particulate leaching procedure and then treated by ammonia plasma. The consequent scaffolds were labeled as aminated PDLLA (A/PDLLA). The pore size, porosity, and surface water contact angle of groups 0 (un-treated control), 5, 10, and 20 minutes A/PDLLA were measured. A/PDLLA scaffolds in groups above were immersed into the FITC labelled GRGDS aqueous solution which contain 1-[3-(dimethylamino) propyl]-3-ethylcarbodiimide hydrochloride (EDC-HCl) and N-hydroxysuccinimide (NHS), the molar ratio of peptides/EDC*HCL/NHS was 1.5 : 1.5 : 1.0, then brachytely slashed for 24 hours in room temperature. The consequent scaffolds were labelled as peptides conjugated A/PDLLA (PA/PDLLA). The scaffolds in groups 0, 5, 10, and 20 minutes A/PDLLA and groups correspondingly conjugation of peptides were detected using X-ray photoelectron spectroscopy (XPS). The scaffolds in groups of conjugation of peptides were measured by confocal laser scanning microscope and high performance liquid chromatography (HPLC), un-treated and un-conjugated scaffolds employed as control. Bone marrow mesenchymal stem cells (BMSCs) from SD rats were isolated and cultured by whole bone marrow adherent culture method. BMSCs at the 3rd-6th passages were seeded to the scaffolds as follows: 20 minutes ammonia plasma treatment (group A/PDLLA), 20 minutes ammonia plasma treatment and conjugation of GRGDS (group PA/PDLLA), and untreated PDLLA control (group PDLLA). After 16 hours of culture, the adhesive cells on scaffolds and the adhesive rate were calculated. After 4 and 8 days of culture, the BMSCs/scaffold composites was observed by scanning electron microscope (SEM). RESULTS: No significant difference in pore size and porosity of PDLLA were observed between before and after ammonia plasma treatments (P > 0.05). With increased time of ammonia plasma treatment, the water contact angle of A/PDLLA scaffolds surface was decreased, and the hydrophilicity in the treated scaffolds was improved gradually, showing significant differences when these groups were compared with each other (P < 0.001). XPS results indicated that element nitrogen appeared on the surface of PDLLA treated by ammonia plasma. With time passing, the peak N1s became more visible, and the ratio of N/C increased more obviously. After PDLLA scaffolds treated for 0, 5, 10, and 20 minutes with ammonia plasma and subsequent conjugation of peptides, the ratio of N/C increased and the peak of S2p appeared on the surface. The confocal laser scanning microscope observation showed that the fluorescence intensity of PA/PDLLA scaffolds increased obviously with treatment time. The amount of peptides conjugated for 10 minutes and 20 minutes PA/PDLLA was detected by HPLC successfully, showing significant differences between 10 minutes and 20 minutes groups (P < 0.001). However, the amount of peptides conjugated in un-treated control and 0, 5 minutes PA/PDLLA scaffolds was too small to detect. After 16 hours co-culture of BMSCs/scaffolds, the adhesive cells and the adhesive rates of A/PDLLA and PA/PDLLA scaffolds were higher than those of PDLLA scaffolds, showing significant difference between every 2 groups (P < 0.01). Also, SEM observation confirmed that BMSCs proliferation in A/PDLLA and PA/PDLLA groups was more detectable than that in PDLLA group, especially in PA/PDLLA group. CONCLUSION: Ammonia plasma treatment will significantly increase the amount of FITC-GRGDS peptides conjugated to surface of PDLLA via amide linkage formation. This new type of biomimetic bone has stabilized bioactivities and has proved to promote the adhesion and proliferation of BMSCs in PDLLA.

[The effect of disc degeneration on the structural property distributions in the cervical vertebral endplates].

OBJECTIVE: To study the effect of disc degeneration on the structural property distributions in the cervical vertebral endplates. METHODS: A 2 mm-diameter hemispherical indenter was used to perform indentation tests at 0.03 mm/s to the depth of 2 mm at 20 normalized locations in 50 bony endplates of intact human cervical vertebrae (C2 approximately C7). The resulting load-displacement curves were used to extract the failure load and stiffness of each test site. Grade of disc degeneration was determined using Nachemson's grading scale. One-way ANOVA, factorial analyses, SNK tests and correlate analyses were used to analyze the result data. RESULTS: Both the failure load and stiffness decreased with disc degeneration in the cervical endplates (P <0.001, both), and correlated significantly with the disc degeneration (rs=-0.429 and rs=-0.244, respectively). Only the distribution of superior cervical endplate changed with disc degeneration, but that of inferior cervical endplate changed little. CONCLUSIONS: The structural property distributions in the cervical vertebral endplates change significantly in the degenerated discs. It suggests that disc degeneration is an important factor to evaluate the intervertebral implant subsidence in anterior cervical fusion.

[Stability analysis of an enhanced load sharing dynamic pedicle screw fixation device and its equivalent rigid device].

OBJECTIVES: To compare the stability of an enhanced load sharing dynamic pedicle screw fixation device with its equivalent rigid device and to evaluate biomechanical roles of the dynamic fixation. METHODS: A model of L(1) body fracture was produced on seven specimens of fresh adult cadaver spine from T(10) to L(4). Both dynamic and rigid devices were applied in the specimens to strength the injured level. Ranges of three dimensional movements and stiffness under flexion-compression were measured in intact, injured and stabilized specimens. RESULTS: Both dynamic and rigid devices were found to provide significant stability for injured segment in flexion-extension and lateral bending. In axial rotation, the devices could restore the stability to levels similar to those in an intact spine. Results indicated 40% increase in range of motion in flexion-extension and 24.1 Nmm reduction in stiffness of flexion-compression for dynamic device, compared with the rigid device. CONCLUSION: The dynamic device offers a design that may enhance load sharing without sacrificing the stability and will decrease stress-shielding and stress concentration.