C1 Transposterior Arch Lateral Mass Screws Combined With C2 Pedicle Screw and Rod Fixation for Pediatric Atlantoaxial Subluxation: A Minimal 10-Year Follow-up Outcome Analysis.

BACKGROUND AND OBJECTIVES: Although the short-term outcomes of the 1-step reduction and fixation technique using C1 transposterior arch lateral mass screws combined with C2 pedicle screw and rod fixation system for the treatment of pediatric atlantoaxial subluxation (AAS) have been satisfactory, its long-term outcomes and impact on spinal development are not well studied. This study was intended to assess the long-term reliability of this technique for pediatric AAS. METHODS: A retrospective case series study was conducted to analyze the minimum 10-year follow-up outcomes from 7 pediatric patients with AAS who underwent atlantoaxial fusion using the aforementioned technique. Quality of life and cervical range of motion were both measured thoroughly. In addition, vertical growth within the fusion construct (C1-2), overall cervical alignment, and subaxial cervical spine degeneration were evaluated radiographically. RESULTS: The mean age of the 7 patients was 8.14 ± 2.41 (6-12) years at the time of surgery. The mean follow-up period was 11.00 ± 1.15 (10-13) years. No patients presented identifiable intervertebral disk degeneration or segmental instability in the subaxial cervical spine except for 1 patient who showed mild intervertebral disk degeneration. Vertical growth did continue within the atlantoaxial complex after surgery (11.90% ± 2.37%); however, there was a decrease in the percentage of vertical growth compared with the corresponding normal populations of the same age and sex. Moreover, there was a significant decrease in the range of cervical extension and rotation motion, and the overall cervical alignment straightened at the latest follow-up. CONCLUSION: The 1-step reduction and fixation technique is a relatively reliable surgical technique for pediatric AAS, which does not adversely affect the postoperative quality of life or the subaxial cervical degeneration. Nevertheless, certain limitations, such as decreased cervical range of motion and changes in cervical alignment, should be concerned.

Novel Radiographic Parameters for Posterior Atlantoaxial Dislocation Secondary to Os Odontoideum and Its Clinical Significance.

OBJECTIVE: To explore correlations of 3 novel radiographic parameters with myelopathy induced by posterior atlantoaxial dislocation (PAAD) secondary to os odontoideum (OO) and assess their reproducibility. METHODS: Of the 51 patients with OO with PAAD enrolled in this study, 28 developed PAAD-induced myelopathy (myelopathy group), and the other 23 patients had no myelopathy (control group). Neurologic function was evaluated by the neurologic function rating system and the Japanese Orthopaedic Association score system. Three novel radiographic parameters (OP [median sagittal diameter of the spinal canal from the posteroinferior edge of the ossicle to the anterosuperior edge of the spinous process of C2]/C4 SAC [space available for spinal cord] ratio, C1 posterior inclination angle, and posterior dislocation index) were measured by lateral cervical dynamic radiography. Their correlations with neurologic function were analyzed, and their reproducibility was assessed by the intraclass correlation coefficient (ICC). In addition, receiver operating characteristic curve analysis was performed. RESULTS: A significant correlation was observed between the OP/C4 SAC ratio and the neurologic function (P < 0.01), and between the C1 posterior inclination angle and the neurologic function (P < 0.01). Furthermore, their interobserver and intraobserver reliability was excellent (ICC ≥ 0.912). Receiver operating characteristic curve analysis showed that the optimal threshold value relating to myelopathy of the OP/C4 SAC ratio and C1 posterior inclination angle was 0.93 and 20°, respectively. CONCLUSIONS: The OP/C4 SAC ratio and the C1 posterior inclination angle seem to be 2 effective and objective radiographic parameters for relating myelopathy in patients with OO with PAAD. When the OP/C4 SAC ratio is <0.93 and/or the C1 posterior inclination angle is >20°, the risk of developing myelopathy should be highly suspected in patients with OO with PAAD.

Factors affecting titanium mesh cage subsidence in single-level anterior cervical corpectomy and fusion for ossification of the posterior longitudinal ligament.

PURPOSE: To analyze risk factors of titanium mesh cage (TMC) subsidence in single-level anterior cervical corpectomy and fusion (ACCF) for cervical ossification of the posterior longitudinal ligament (OPLL). METHODS: TMC subsidence is defined as the reduction of the adjacent vertebral bodies by ≥ 2 mm. Patients with cervical OPLL who were treated with single-level ACCF between January 2019 and May 2021 were retrospectively analyzed in two groups: patients with TMC subsidence as Group S and patients with no TMC subsidence as Group N during the one-year follow-up period. The degree of distraction of surgical segment and correction of the cervical curvature was measured to analyze their relationship with TMC subsidence. RESULTS: A total of 128 patients were included in Group S, and 138 patients were included in Group N. There was no significant difference in patient demographics and complications between the two groups. The degree of distraction in Group S was significantly higher than that in Group N (11.4% ± 7.6% vs. 4.7% ± 9.7%, P < 0.01). The change of C2 to C7 Cobb angle (α) in Group S was significantly greater than that in Group N (5.7 ± 2.7 vs. 1.4 ± 4.7, P < 0.01), and the change of interspinous process distance (SPD) in Group S was also significantly greater than that in Group N (7.0 ± 4.2 vs. 4.1 ± 2.7, P < 0.01). The JOA score and JOA recovery rate were not statistically different between the two groups. CONCLUSIONS: Intraoperative selection of overlength TMC in single-level ACCF for OPLL, over-distraction and excessive correction of the cervical curvature may cause TMC subsidence after surgery. No significant impact of TMC subsidence on the surgical outcome was observed during the 1-year follow-up period.

Risk Factors for Poor Prognosis of Spinal Cord Injury without Radiographic Abnormality Associated with Cervical Ossification of the Posterior Longitudinal Ligament.

PURPOSE: To investigate the factors associated with the prognosis of spinal cord injury without radiographic abnormality (SCIWORA) accompanied by cervical ossification of the posterior longitudinal ligament (C-OPLL). METHODS: We retrospectively investigated 287 patients with SCIWORA associated with C-OPLL, who were admitted within 30 days after trauma to our facility between August 2014 and August 2018. All patients were divided into the good or poor prognosis group. Patient demographics were analyzed. Besides, occupying ratio on CT and spinal cord high signal changes in MRI T2WI were measured and recorded. Multivariate linear regression was applied to analyze the correlation of prognosis with spinal cord high signal changes in MRI T2WI, cause of injury, and occupying ratio. RESULTS: Occupying ratio of ossification mass was 43.5 ± 10.7% in the poor prognosis group and 27.3 ± 7.7% in the good prognosis group. The occurrence rate of high signal changes in MRI T2WI was 84.2% in the poor prognosis group and 41.3% in the good prognosis group. Poor prognosis was correlated with high occupying ratio and spinal cord high signal changes in MRI T2WI. In the patient with SCIWORA associated with C-OPLL, ROC curve of occupying ratio showed 30% as a predictor for the poor prognosis. Among the 92 patients with occupying ratio ≤ 30%, poor prognosis was observed in 5 cases (5.4%), whereas in the 72 cases with occupying ratio > 30%, poor prognosis was seen in 33 cases (45.8%). Postoperative AIS grade at final follow-up in occupying ratio > 30% group was significantly worse. CONCLUSIONS: Patients suffering from SCIWORA with C-OPLL have poor prognosis when they have higher occupying ratio of ossification mass and spinal cord high signal changes in MRI T2WI. The cut-off value of occupying ratio for predicting the poor prognosis was 30% in patients with SCIWORA associated with C-OPLL.

Cyclic Tensile Stress to Rat Thoracolumbar Ligamentum Flavum Inducing the Ossification of Ligamentum Flavum: An In Vivo Experimental Study.

STUDY DESIGN: Western blot, reverse transcription-polymerase chain reaction (RT-PCR), radiological, and histological analyses of the rat ossification of ligamentum flavum (OLF) induced by cyclic tensile stress. OBJECTIVE: The aim of this study was to induce the OLF using cyclic tensile stress to rat thoracolumbar ligamentum flavum, and to investigate the possible molecular mechanism of tension-induced OLF. SUMMARY OF BACKGROUND DATA: Tensile stress has been considered as an important factor leading to the OLF. So far, however, no OLF induced by tension has been reported. METHODS: Forty rats were randomly divided into five equal groups. For control groups, the blank and anesthesia groups were not subjected to tension. For experimental groups, the 4-, 8-, and 12-week groups were subjected to cyclic tensile stress of ligamentum flavum after abdominal anesthesia for 4 weeks, 8 weeks, and 12 weeks, respectively, using an original stress apparatus for rats. The radiological and morphological changes of rat spine, as well as the protein and mRNA expressions of CD44, bone morphogenetic protein-2 (BMP-2), integrin ß3, collagen protein type I (COL1), osteopontin (OPN), runt-related transcription factor 2 (RUNX-2), and vascular endothelial growth factor (VEGF), were concerned. RESULTS: The micro-CT showed OLF in the 4-, 8-, and 12-week group. The axial maximum occupied area of ossifications was 1.42 mm2, 3.35 mm2, and 7.28 mm2, respectively. In histopathology, chondrocytes proliferated in the experimental model; woven bone arose in the 8- and 12-week groups, and was more noticeable in the 12-week group. According to western blot and RT-PCR, the expressions of seven osteogenesis-related molecules were all increased in three experimental groups. CONCLUSION: Cyclic tensile stress to the ligamentum flavum in rats can induce the OLF, and the longer the duration, the more visible the osteogenesis. The upregulation and synergism of osteogenesis-related molecules may contribute to the OLF induced by tensile stress.Level of Evidence: N/A.

Screening and validation of candidate genes involved in the regulation of egg yolk deposition in chicken.

Eggs with the same total weight may have considerable differences in yolk weight. Eggs with a high percentage of yolk have a higher nutritional value, more flavor, and are more desirable to consumers. However, a large yolk proportion means more dry matter in the eggs, which reduces the feed efficiency. The elucidation of the genetic factors of yolk quantity in eggs is of scientific and practical significance. Through RNA sequencing, we explored the transcriptome of ovarian tissue from 12 Wenchang chickens, including 6 chickens that laid eggs with a high yolk percentage (32%) and 6 that laid low yolk percentage eggs (25%). We identified a total of 362 differentially expressed genes (P-value < 0.01, log2 fold change < -1, log2 fold change > 1), of which 220 were upregulated and 142 were downregulated in high yolk percentage hens. According to the Gene Ontology terms annotation and Kyoto Encyclopedia of Genes and Genomes enrichment analysis, the differentially expressed genes were associated with the regulation of various cell functions, cell differentiation and development, neuroactive ligand-receptor interactions, and calcium and ubiquitin-mediated proteolysis signaling pathways. To further filter for genes that were directly involved in yolk accumulation, the chicken quantitative trait loci database, genes within 100 kb upstream and downstream of the yolk weight trait SNP, and intersection genes in protein-protein interaction network diagrams were used to detect genes that overlapped with the differentially expressed genes. We found 7 candidate genes in total, MNR2, AOX1, ANTXRL, GRAMD1C, EEF2, COMP, and JUND, which affect female reproductive performance and the growth and development of follicles, supporting cell transport, cell proliferation, and differentiation. All candidate genes and several randomly selected genes were verified by quantitative real time PCR, and the results were consistent with the RNA sequencing. In conclusion, investigating the molecular mechanisms of high yolk percentage traits will allow breeding strategies to be optimized to alter the percentage of yolk in chicken eggs.

The role of lncRNA-MEG/miR-21-5p/PDCD4 axis in spinal cord injury.

Spinal cord injury (SCI) is an insult to the spinal cord resulting in a change, either temporary or permanent, in its normal motor or sensory function, but the mechanism of neuron loss after spinal cord injury is still unclear. Long non-coding RNAs (lncRNAs) can play an important role in regulating cell physiological activities through competitively binding to miRNAs. However, there is still a lack of research on the effect of lncRNAs on SCI. In this study, we selected SCI gene expression data and miRNA expression data from the NCBI database for differential expression analysis, and predicted miRNA target genes. Subsequently, biological analysis of gene expression and miRNA changes was performed on a rat SCI model. The results showed that the expression level of lncRNA-MEG increased significantly in rat SCI model. Subsequently, we found that lncRNA-MEG can promote the expression level of PDCD4 by inhibiting miR-21-5p, which leads to neuronal cell apoptosis. Furthermore, knocking down of lncRNA-MEG with shRNA can reverse the effect of miR-21-5p and inhibit the effect of PDCD4 to reduce the expression of apoptosis-related proteins. Furthermore, we found lncRNA-MEG can regulate PDCD4 expression through miR-21-5p by targeting 3'UTR of PDCD4 in the OGD cell model. In summary, we first discovered lncRNA-MEG regulates neuronal cell apoptosis through miR-21-5p by targeting PDCD4 in SCI.

Design and application of a novel patient-specific 3D printed drill navigational guiding template in percutaneous thoracolumbar pedicle screw fixation: A cadaveric study.

The conventional surgical method of percutaneous pedicle screw fixation (PPSF) mainly uses X-ray fluoroscopy guidance to target the vertebral pedicle for screw placement. This study aimed to explore the feasibility of establishing a personalized drill guide template for PPSF based on a three-dimensional (3D) printing technique and to evaluate the accuracy and safety of the method for assisting screw insertion in cadaveric specimens. The T3-L3 trunk cadaveric specimens from six adults were subject to a computed tomography (CT) scan in the prone position. A three-dimensional model containing the back skin contour was reconstructed. A bilateral ideal pedicle screw in the T6-L1 segment was designed. Then, the reverse templates were designed. The two templates were fused and printed into an individualized guide template. PPSF was performed under the assistance of the guide template, and the CT scan was taken postoperatively to access the screw position. Ninety-six pedicle screws were successfully placed on the bilateral vertebral body of the T6-L1 segment with the assistance of a guide template. The guide plate was not loosened or displaced when operated by a single hand, and the operation time was 24.6 ± 7.9 s. The axial CT images after puncture indicated that in 96 puncture needles, 90 needles were grade I and 6 were grade II, with a puncture accuracy rate of 98.6%. In conclusion, an individualized PPSF navigation template was developed using Mimics software and 3D printing prototyping, which improved the accuracy of PPSF in cadaveric specimens.

Comparison of Effects of PELD and Fenestration in the Treatment of Geriatric Lumbar Lateral Recess Stenosis.

PURPOSE: Although degenerative lumbar spinal stenosis (LSS) is increasingly being diagnosed in older people, there is much uncertainty about the appropriate operative treatment options. The objective of this study was to compare the outcome of percutaneous endoscopic lumbar decompression (PELD) versus fenestration for lumbar lateral recess stenosis (LRS) in geriatric patients over 75 years old. MATERIALS AND METHODS: This prospective controlled study was performed on 46 consecutive over aged patients with lateral recess stenosis who underwent either PELD or fenestration. Clinical data were recorded before, 1 week, 3 months and 1.5 years after surgery using visual analog scale (VAS), Japanese Orthopaedic Association Score (JOA), The Short-Form-36 (SF-36), and the modified Macnab evaluation criteria. RESULTS: The patients' mean age was 82.7 years (aged 75-93 years) in PELD group and 79.1 years (aged 75-88 years) in fenestration group. No statistical difference was found between PELD group and fenestration group with regards to VAS-back pain, VAS-leg pain, JOA and at 3 months and 1.5-year follow-up. However, the PELD group had a lower mean VAS for back pain at 1 week postoperatively (P<0.05). The quality of life in PELD group achieved the same remarkable improvement as fenestration group (P>0.05). Operative time (min) was similar between two groups (p>0.05), while the PELD techniques brought advantages in blood loss (mL) (48.3 vs 128.2, p<0.05), early ambulation (h) (5.5 vs 25.2, p<0.05), and anesthesia-related complications. CONCLUSION: Both PELD and fenestration showed favorable clinical outcomes for the treatment of lumbar lateral recess stenosis. In addition, PELD had advantages such as reduced traumatization and less anesthesia-related complications. In terms of quality of life and complications after operation, PELD under local anesthesia could be an efficient supplement to conventional decompression surgery in geriatric patients with lumbar lateral recess stenosis.

Preparation and Assessment of an Individualized Navigation Template for Lower Cervical Anterior Transpedicular Screw Insertion Using a Three-Dimensional Printing Technique.

STUDY DESIGN: Prospective trial. OBJECTIVE: To establish an individualized navigation template for safe and accurate insertion of lower cervical anterior transpedicular screw (ATPS) based on a three-dimensional (3D) printing technique. SUMMARY OF BACKGROUND DATA: Conventional screw insertion manually under fluoroscopy easily leading to deviation of ATPS screw channel, cervical instrumentation procedures demand the need for a precise technique for screw placement. METHODS: Twenty adult cervical spine specimens (10 men and 10 women, with a mean age of 50.29 ±â€Š6.98) were selected for computed tomography pre- and postoperatively. A 3D lower cervical spine model was reconstructed using Mimics software to measure the screw-related parameters and generate a reverse template with optimal screw channel as well as a prototype using 3D printing. Assisted by the navigation template, bilateral ATPS were inserted into the cadavers. RESULTS: The mean outer width and height of pedicle were 5.31 ±â€Š1.23 and 6.78 ±â€Š1.10 mm, respectively. The average length, sagittal, and axial angles of the optimal screw channel obtained through the optimal entry point were 36.34 ±â€Š4.39 mm, 40.67°â€Š±â€Š5.10°, and 93.7°â€Š±â€Š7.96°, respectively. The adjustable safe ranges of sagittal and axial angles were 3.89°â€Š±â€Š1.13° and 5.64°â€Š±â€Š0.97°, respectively. The axial and sagittal accuracies of the 200 screws were 99.5% and 97%, respectively. The average deviations of the actual entry point and the preset opening in the X, Y, and Z axes were 0.39 ±â€Š0.43, 0.21 ±â€Š0.41, and 0.29 ±â€Š0.14 mm, respectively (P > 0.05). CONCLUSION: An individualized ATPS navigation template was developed using Mimics software and 3D printing prototyping, based on computed tomography, for highly accurate screw insertion. LEVEL OF EVIDENCE: 4.

A Comparison of Multilevel Anterior Cervical Discectomy and Corpectomy in Patients With 4-level Cervical Spondylotic Myelopathy: a Minimum 2-year Follow-up Study: Multilevel Anterior Cervical Discectomy.

STUDY DESIGN: Retrospective clinical series. OBJECTIVES: To compare perioperative parameters, clinical outcomes, radiographic parameters, and complication rates of segmental anterior cervical corpectomy and fusion (sACCF) plus preservation of middle vertebrae with those of multilevel anterior cervical discectomy and fusion (mACDF) in 70 patients with 4-level cervical spondylotic myelopathy (CSM). METHODS: Between July 2006 and May 2011, 70 consecutive patients [49 males and 21 females; mean age 56.8 y (range, 38-72 years)] with 4-level CSM were enrolled in this study and divided into sACCF (n=39) group and mACDF (n=31) group. The study compared perioperative parameters, complication rates, clinical parameters, and radiologic parameters. RESULTS: No significant differences between the groups were found in demographic, baseline disease characteristics, operation time, hospital stay, and follow-up time. Significant improvements of clinical outcome were seen from preoperative to postoperative in both groups. Satisfaction was rated as excellent or good by 79.5% of the sACCF group and 80.6% of the mACDF group, which was not a significant difference. Mean postoperative cervical lordosis was significantly greater in the mACDF group than in the sACCF group. Blood loss was significantly greater in the sACCF group than in the mACDF group and instrumentation-related and/or graft-related complication rate significantly lower for the mACDF group. Both sACCF and mACDF groups achieved solid fusion rates (87.1% and 90.3%, respectively). CONCLUSIONS: Both mACDF and sACCF provide satisfactory clinical outcomes and fusion rates for 4-level CSM. However, mACDF is associated with better radiologic parameter, less blood loss, and lower instrumentation-related and/or graft-related complication rate.

MicroRNA-221 is involved in the regulation of osteoporosis through regulates RUNX2 protein expression and osteoblast differentiation.

INTRODUCTION: MicroRNAs (miRNAs) has emerged as important factors in osteogenesis and chondrogenesis. This study aimed to determine whether miR-221 is involved in the regulation of osteoporosis and its underlying mechanism. METHODS: Total RNA was extracted from fresh femoral neck trabecular bone from women undergoing hip replacement due to either osteoporotic fracture (OP group, n = 12) or osteoarthritis in the absence of osteoporosis (Control group, n = 12). Gene expression was quantified using TaqMan quantitative RT-PCR assays and protein production was determined by western blot analysis. The role of miR-221 in osteoblast differentiation was identified by gain or loss function experiment. MiRNA targets were identified using bioinformatics and luciferase reporter assay. RESULTS: MiR-221 was down-regulated in the osteoporotic samples compared with non-osteoporotic controls, and decreased in a C2C12 cell model of osteogenic differentiation. Overexpression of miR-221 resulted in a decrease in the osteogenic potential, as indicated by the reduced expression levels of key osteoblast markers, including osteocalcin (OC), alkaline phosphatase (ALP) and collagen, type I, α 1 (COL1A1), whereas inhibition of miR-221 promoted the activity of OC, ALP and COL1A1. Then bioinformatic analysis identified potential target sites of the miR-221 located in the 3' untranslated regions of RUNX2. Western blot analysis demonstrated that miR-221 inhibited RUNX2 gene expression. Furthermore, dual-luciferase reporter assays confirmed that RUNX2 was a direct target of miR-221. Rescue experiments showed that overexpression of RUNX2 significantly attenuated the effect of miR-221 on osteoblast markers providing strong evidence that miR-221 mediated the osteoblast differentiation by targeting RUNX2. CONCLUSIONS: Taken together, these data implied that miR-221 played an important part in osteoporosis through regulating RUNX2 expression and osteoblast differentiation.

A Novel High Mechanical Property PLGA Composite Matrix Loaded with Nanodiamond-Phospholipid Compound for Bone Tissue Engineering.

A potential bone tissue engineering material was produced from a biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), loaded with nanodiamond phospholipid compound (NDPC) via physical mixing. On the basis of hydrophobic effects and physical absorption, we modified the original hydrophilic surface of the nanodiamond (NDs) with phospholipids to be amphipathic, forming a typical core-shell structure. The ND-phospholipid weight ratio was optimized to generate sample NDPC50 (i.e., ND-phospholipid weight ratio of 100:50), and NDPC50 was able to be dispersed in a PLGA matrix at up to 20 wt %. Compared to a pure PLGA matrix, the introduction of 10 wt % of NDPC (i.e., sample NDPC50-PF10) resulted in a significant improvement in the material's mechanical and surface properties, including a decrease in the water contact angle from 80 to 55°, an approximately 100% increase in the Young's modulus, and an approximate 550% increase in hardness, thus closely resembling that of human cortical bone. As a novel matrix supporting human osteoblast (hFOB1.19) growth, NDPC50-PFs with different amounts of NDPC50 demonstrated no negative effects on cell proliferation and osteogenic differentiation. Furthermore, we focused on the behaviors of NDPC-PFs implanted into mice for 8 weeks and found that NDPC-PFs induced acceptable immune response and can reduce the rapid biodegradation of PLGA matrix. Our results represent the first in vivo research on ND (or NDPC) as nanofillers in a polymer matrix for bone tissue engineering. The high mechanical properties, good in vitro and in vivo biocompatibility, and increased mineralization capability suggest that biodegradable PLGA composite matrices loaded with NDPC may potentially be useful for a variety of biomedical applications, especially bone tissue engineering.

Comparison of two reconstructive techniques in the surgical management of four-level cervical spondylotic myelopathy.

To compare the clinical efficacy and radiological outcome of treating 4-level cervical spondylotic myelopathy (CSM) with either anterior cervical discectomy and fusion (ACDF) or "skip" corpectomy and fusion, 48 patients with 4-level CSM who had undergone ACDF or SCF at our hospital were analyzed retrospectively between January 2008 and June 2011. Twenty-seven patients received ACDF (Group A) and 21 patients received SCF. Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI) score, and Cobb's angles of the fused segments and C2-7 segments were compared in the two groups. The minimum patient follow-up was 2 years. No significant differences between the groups were found in demographic and baseline disease characteristics, duration of surgery, or follow-up time. Our study demonstrates that there was no significant difference in the clinical efficacy of ACDF and SCF, but ACDF involves less intraoperative blood loss, better cervical spine alignment, and fewer postoperative complications than SCF.

Anterior discectomy/corpectomy and fusion with internal fixation for the treatment of unstable hangman's fractures: a retrospective study of 38 cases.

OBJECT: The object of this study was to describe the authors' method of anterior discectomy/corpectomy and fusion combined with internal fixation for the treatment of unstable hangman's fractures and to evaluate the clinical and radiological outcomes. METHODS: This study included 38 consecutive patients who underwent surgery for unstable hangman's fractures between July 2002 and October 2011 and were followed up for more than 2 years. The patients were 18 women and 20 men with a mean age of 42.8 years (range 20-69 years). The fracture resulted from a fall in 9 patients, a motor vehicle accident in 21 patients, and a motorcycle accident in 8 patients. The Levine-Edwards classification was Type II in 13 patients, Type IIA in 20 patients, and Type III in 5 patients. All patients underwent anterior C2-3 intervertebral disc excision or C-3 corpectomy, decompression and reduction, interbody implantation of an autologous iliac bone graft, and internal fixation with a titanium plate. Pain was assessed before and after surgery using a visual analog scale (VAS). Myelopathy was graded using the Japanese Orthopaedic Association (JOA) score. Patient satisfaction with the surgery was assessed using Odom's grading system. Anteroposterior, lateral, and dynamic (flexion/extension) radiographs were obtained during the follow-up period. Two-dimensional CT studies with sagittal and coronal reconstructions were routinely performed. RESULTS: The mean follow-up period was 49.2 months (range 24-132 months). There was a significant decrease between the preoperative and final follow-up VAS scores (mean [SD] 7.56 ± 1.52 vs 2.36 ± 1.25, p < 0.05) and a significant increase between the preoperative and final follow-up JOA scores (12.58 ± 1.34 vs 16.13 ± 1.17, p < 0.05). Postoperative radiographs showed satisfactory reduction of the fracture in all cases. Postoperative complications included transient neurological deficits (3 cases), hematoma (2 cases), temporary dysphagia (5 cases), temporary hoarseness (2 cases), prolonged pain at the iliac crest donor site (4 cases), and wound infection at the iliac crest donor site (2 cases). Solid fusion was achieved in 94.7% of patients at the final follow-up. CONCLUSIONS: Anterior discectomy/corpectomy and fusion combined with internal fixation is a safe and effective procedure for the treatment of unstable hangman's fractures.

Effectiveness of tranexamic acid in reducing blood loss in spinal surgery: a meta-analysis.

BACKGROUND: The aim of present meta-analysis was to evaluate the effectiveness of tranexamic acid (TXA) use in reducing blood loss and the related thrombotic complications in spinal surgery. METHODS: Three databases (MEDLINE, EMBASE, and the Cochrane Library) were searched through October 2012 to identify the relevant randomized controlled trials (RCTs) regarding the TXA effective in spinal surgery. Mean differences (MDs) of blood loss, blood transfusions, and postoperative partial thromboplastic time (PTT), odds ratios (ORs) of blood transfusion and thrombotic complication in TXA-treated group compared to placebo group were extracted and combined using random-effect meta-analysis. RESULTS: A total of 6 RCTs comprising 411 patients were included in the meta-analysis according to the pre-defined selection criteria. TXA-treated group had significantly less amount of blood loss and blood transfusions per patient, and had smaller proportion of patients who required a blood transfusion compared with the placebo group. The use of TXA can significantly reduce the postoperative PTT with weighted MD of -1.59 [(95% confidence interval (CI):-3.07, -0.10] There is a null association between thrombosis complications and the use of TXA. CONCLUSION: We conclude that the use of TXA in patients undergoing spinal surgery appears to be effective in reducing the amount of blood loss, the volume of blood transfusion, the transfusion rate, and the postoperative PTT. However, data were too limited for any conclusions regarding safety. More high-quality RCTs are required before recommending the administered of TXA in spinal surgery.

[A cadaveric study on establishing an individualized navigation template for the placement of occipital condyle screws using a three-dimensional printing technique].

OBJECTIVES: To investigate the feasibility of establishing an individualized navigation template for occipital condyle screws insertion using a fused deposition modeling based three-dimensional printing forming technique, and to evaluate the accuracy and safety of template-assisted condyle screw insertion. METHODS: Thirty adult occipitocervical specimens were selected to take a CT-scan. After original Dicom data imported into the Mimics software, the craniocervical junction models were created, which were used to evaluate anatomic structures and define the screw-related parameters. Design and generate the cavity models of the occipital condyle based on a three-dimensional printing forming technique. After using a free-hand procedure to create a navigation template with a well-established screw path, finish bilateral condyle screws insertion assisted by the navigation template. Anatomy study and CT-scan were taken postoperatively to access the position of the screws. RESULTS: Sixty condyle screws were implanted assisted by 30 individualized navigation templates with an average time cost of (91.4 ± 8.2) s. The axial medial angle, sagittal cranial angle and distance between the entry point to atlantooccipital joint surface were (33.2 ± 6.4)°, (8.9 ± 3.4)°, (3.9 ± 0.9) mm, respectively. The variations due to different sex and sides resulted in a statistically insignificant difference of the parameters. Anatomy study and CT-scan indicated no intrusion of the vertebral artery, hypoglossal canal, condyle emissary vein canal or atlantooccipital joint. Fifty-nine condyle screws were completely contained within the condyle, while only 1 screw perforated lateral condyle wall. CONCLUSIONS: Using the Mimics software for establishing the occipital condyle and related cavity model based on CT-scan images proves to be a feasible and precise method.Occipital condyle screws insertion assisted by a three-dimensional printing model is highly accurate and simple, which could be a new alternative to conventional technique.

Enhanced p62 expression triggers concomitant autophagy and apoptosis in a rat chronic spinal cord compression model.

Chronic spinal cord compression is the result of mechanical pressure on the spinal cord, which in contrast to traumatic spinal cord injury, leads to slowly progressing nerve degeneration. These two types of spinal cord injuries may trigger similar mechanisms, including motoric nerve cell apoptosis and autophagy, however, depending on differences in the underlying injury severity, nerve reactions may predominantly involve the conservation of function or the initiation of functions for the removal of irreversibly damaged cells. p62 is a multidomain adapter protein, which is involved in apoptosis and cell survival as well as autophagy, and is a common component of protein aggregations in neurodegenerative diseases. In the present study, a rat chronic spinal cord compression model was used, in which the spinal cord was progressively compressed for six weeks and then constantly compressed for another 10 weeks. As a result Basso, Beattie and Bresnahan locomotor scaling revealed a gradual score decrease until the 6th week followed by constant recovery until the 16th week after spinal cord compression was initiated. During the first eight weeks of the experiment, p62 and nuclear factor-κB (NF-κB) were increasingly expressed up to a constant plateau at 12-16 weeks, whereas caspase 3 exhibited a marginally enhanced expression at 8 weeks, however, reached a constant maximum peak 12-16 weeks after the beginning of spinal cord compression. It was hypothesized that, in the initial phase of spinal cord compression, enhanced p62 expression triggered NF-κB activity, directing the cell responses mainly to cell survival and autophagy, whereas following eight weeks of spinal cord compression, caspase 3 was additionally activated indicating cumulative elimination of irreversibly damaged nerve cells with highly activated autophagy.

Anterior fusion technique for multilevel cervical spondylotic myelopathy: a retrospective analysis of surgical outcome of patients with different number of levels fused.

OBJECTIVE: The anterior approach for multilevel CSM has been developed and obtained favorable outcomes. However, the operation difficulty, invasiveness and operative risks increase when multi-level involved. This study was to assess surgical parameters, complications, clinical and radiological outcomes in the treatment of 2-, 3- and 4-level CSM. METHODS: A total of 248 patients with 2-, 3- or 4-level CSM who underwent anterior decompression and fusion procedures between October 2005 and June 2011 were divided into three groups, the 2-level group (106 patients), the 3-level group (98 patients) and the 4-level group (44 patients). The clinical and Radiographic outcomes including Japanese Orthopedic Association (JOA) score, Neck Disability Index (NDI) score, Odom's Scale, hospital stay, blood loss, operation time, fusion rate, cervical lordosis, cervical range of motion (ROM), and complications were compared. RESULTS: At a minimum of 2-year follow-up, no statistical differences in JOA score, NDI score, Odom's Scale, hospital stay, fusion rate and cervical lordosis were found among the 3 groups. However, the mean postoperative NDI score of the 4-level group was significantly higher than that in the other two groups (P<0.05), and in terms of postoperative total ROM, the 3-level group was superior to the 4-level group and inferior to 2-level group (P<0.05). The decrease rate of ROM in the 3-level group was significantly higher than that in the 2-level group, and lower than that in the 4-level group (P<0.05). CONCLUSIONS: As the number of involved levels increased, surgical results become worse in terms of operative time, blood loss, NDI score, cervical ROM and complication rates postoperatively. An appropriate surgical procedure for multilevel CSM should be chosen according to comprehensive clinical evaluation before operation, thus reducing fusion and decompression levels if possible.

Clinical and radiologic comparison of dynamic cervical implant arthroplasty versus anterior cervical discectomy and fusion for the treatment of cervical degenerative disc disease.

This study compared the clinical and radiological outcomes of dynamic cervical implant (DCI; Scient'x, Villers-Bretonneux, France) arthroplasty versus anterior cervical discectomy and fusion (ACDF) for the treatment of cervical degenerative disc disease. This prospective cohort study enrolled patients with single-level cervical degenerative disc disease who underwent DCI arthroplasty or ACDF between September 2009 and June 2011. Patients were followed up for more than 2years. Clinical evaluation included the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), Neck Disability Index (NDI), Japan Orthopedic Association (JOA) score, and visual analog scale (VAS) scores for neck and arm pain. Radiological assessments included segmental range of motion (ROM), overall ROM (C2-C7), disc height (DHI), and changes in adjacent disc spaces. The VAS, SF-36, JOA, and NDI scores improved significantly after surgery in both the DCI and ACDF groups. The VAS, JOA, and SF-36 scores were not significantly different between the DCI and ACDF groups at the final follow-up. The segmental ROM at the treated level and overall ROM increased significantly after surgery in the DCI group, but the ROM in the adjacent cephalad and caudal segments did not change significantly. The mean DHI at the treated level was significantly restored after surgery in both groups. Five patients (12.8%) in the DCI group showed new signs of adjacent segment degeneration. These results indicate that DCI is an effective, reliable, and safe procedure for the treatment of cervical degenerative disc disease. However, there is no definitive evidence that DCI arthroplasty has better intermediate-term results than ACDF.