With the development of three-dimensional (3D) printing technology, more and more researches have focused on its application in the region of intervertebral fusion materials; the prospects are worth looking forward to. This article reviews the researches about 3D printing technology in spinal implants, and summarizes the materials and printing technology applied in the field of spinal interbody fusion, and the shortcomings in the current research and application. With the rapid development of 3D printing technology and new materials, more and more 3D printing spinal interbodies will be developed and used clinically.
Traditional bone repair materials, such as titanium, polyetheretherketone, and calcium phosphate, exhibit limitations, including poor biocompatibility and incongruent mechanical properties. In contrast, ceramic-polymer composite materials combine the robust mechanical strength of ceramics with the flexibility of polymers, resulting in enhanced biocompatibility and mechanical performance. In recent years, researchers worldwide have conducted extensive studies to develop innovative composite materials and manufacturing processes, with the aim of enhancing the bone repair capabilities of implants. This article provides a comprehensive overview of the advancements in ceramic-polymer composite materials, as well as in 3D printing and surface modification techniques for composite materials, with the objective of offering valuable insights to improve and facilitate the clinical application of ceramic-polymer composite materials in the future.
ObjectiveTo explore the feasibility of co-transduction and co-expression of Nogo extracellular peptide residues 1-40 (NEP1-40) gene and neurotrophin 3 (NT-3) gene into neural stem cells (NSCs).MethodsNSCs were derived from the cortex tissue of Sprague Dawley rat embryo. The experiment included 5 groups: no-load lentiviral vector transducted NSCs (group A), NEP1-40 transducted NSCs (group B), NT-3 transducted NSCs (group C), NEP1-40 and NT-3 corporately transducted NSCs (group D), and blank control (group E). Target genes were transducted into NSCs by lentiviral vectors of different multiplicity of infection (MOI; 5, 10, 15) for different time (24, 48, 72 hours). Fluorescent microscope was used to observe the expression of fluorescence protein and acquire the optimum MOI and optimum collection time. Real-time fluorescence quantitative PCR and Western blot tests were utilized to evaluate the gene expressions of NEP1-40 and NT-3 in NSCs and protein expressions of NEP1-40 and NT-3 in NSCs and in culture medium.ResultsThe optimum MOI for both target gene was 10 and the optimum collection time was 48 hours. The real-time fluorescence quantitative PCR and Western blot results showed that the mRNA and protein relative expressions of NEP1-40 in groups B and D were significantly higher than those in groups A and C (P<0.05), but no significant difference was found between groups B and D, and between groups A and C (P>0.05). The mRNA and protein relative expressions of NT-3 in groups C and D were significantly higher than those in groups A and B (P<0.05), but no significant difference was found between groups A and B, and between groups C and D (P>0.05).ConclusionNEP1-40 and NT-3 gene can be successfully co-transducted into NSCs by the mediation of lentiviral vector. The expressions of the two target genes are stable and have no auxo-action or antagonism between each other.
ObjectiveTo evaluate the mid-term clinical and radiological results of dynamic cervical implant (DCI) arthroplasty for degenerative cervical disc disease in Chinese population.MethodsBetween April 2010 and June 2011, 25 patients with single-segmental degenerative cervical disc disease underwent DCI replacement. Visual Analogue Scale (VAS), Japanese Orthopaedic Association (JOA) scores, Neck Disability Index (NDI) and 36-Item Short Form Health Survey Questionnaires (SF-36) were used for evaluation of neurological function and pain severity, before and after operation, and during follow-up period. Radiographic evaluation included range of motion (ROM) of C2–7, surgical segments and adjacent level, intervertebral height of the surgical segments, migration, subsidence of the implant and heterotopic ossification (HO).ResultsThe mean follow-up period was 72.3 months (ranged from 68 to 78 months). The VAS, JOA, NDI, and SF-36 mental and physical component summaries improved significantly after surgery (P<0.05) and remained stable over the whole observation period. The ROM (flexion/extension) and intervertebral height at the level treated with DCI remained at the first 2 years and partly reduced at the final follow-up. ROM for C2–7 and adjacent levels maintained during the follow-up period. DCI subsidence was observed in 11 segements, and 9 segements appeared heterotopic ossification.ConclusionsClinical efficacy of DCI arthroplasty improves and maintaines during the mid-to-long period of follow-up. HO formation is a common phenomenon, leading a dramatic decrease of ROM at index level and recurrence of neurological symptoms. Rate of implant subsidence and migration is relatively high, leaving a potential risk of symptom at index level and adjacent segment degeneration. It suggests that for patients with degenerative cervical disc disease, total disc replacement or anterior cervical discectomy and fusion is still the first choice instead of DCI arthroplasty.
ObjectiveTo introduce a new occipitocervical angle parameter, occipito-odontoid angle (O-Da), for predicting dysphagia after occipitocervical fusion (OCF) in patients with C2, 3 Klippel-Feil syndrome (KFS) and analyze its effectiveness. Methods A total of 119 patients met selective criteria between April 2010 and November 2019 were retrospectively included as the study subjects. There were 56 males and 63 females. The age ranged from 14 to 76 years, with a median age of 51 years. There were 44 cases of basilar invagination and 75 cases of atlantoaxial subluxation. Forty patients were combined with C2, 3 KFS. Seven patients underwent anterior decompression combined with posterior OCF and 112 patients underwent posterior OCF. The fixed segments were O-C2 in 36 cases, O-C3 in 51 cases, O-C4 in 25 cases, and O-C5 in 7 cases. All patients were followed up 21-136 months, with a median time of 79 months. The lateral cervical X-ray films before operation and at last follow-up were used to measure the occipital to C2 angle (O-C2a), the occipital and external acoustic meatus to axis angle (O-EAa), the occipital protuberance to axial angle (Oc-Axa), the O-Da, and the narrowest oropharyngeal airway space (nPAS). The differences of the above parameters between the last follow-up and the preoperative values were calculated (represented as dO-C2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS). Patients were divided into two groups according to whether they suffered dysphagia after operation, and the differences in clinical data and radiographic parameters were compared between the two groups. The correlation between occipitocervical angle parameters and nPAS in 40 patients with C2, 3 KFS was analyzed respectively. In addition, sensitivity and specificity analyses were used to assess the effectiveness of dO-Da≤−5° for the prediction of postoperative dysphagia. ResultsThirty-one patients (26.1%) suffered dysphagia after OCF (dysphagia group), including 10 patients with C2, 3 KFS; no dysphagia occurred in 88 patients (non-dysphagia group). There was no significant difference in age, follow-up time, fixed segment, proportion of patients with rheumatoid arthritis, proportion of patients with atlantoaxial subluxation, and proportion of patients with C2, 3 KFS between the two groups (P>0.05). The proportion of female patients was significantly higher in dysphagia group than in non-dysphagia group (χ2=7.600, P=0.006). The difference in preoperative O-C2a between the two groups was significant (t=2.528, P=0.014). No significant differences were observed in preoperative O-EAa, Oc-Axa, O-Da, and nPAS (P>0.05). There was no significant difference in dO-C2a, dO-EAa, dOc-Axa, dO-Da, and dnPAS between the two groups (P>0.05). The dO-C2a, dO-EAa, dOc-Axa, and dO-Da were positively correlated with dnPAS in 40 patients with C2, 3 KFS (r=0.604, P<0.001; r=0.649, P<0.001; r=0.615, P<0.001; r=0.672, P<0.001). Taking dO-Da≤−5° as the standard, the sensitivity and specificity of dO-Da to predict postoperative dysphagia in patients with C2, 3 KFS were 80.0% (8/10) and 93.3% (28/30), respectively. ConclusionThe dO-Da is a reliable indicator for predicting dysphagia after OCF in patients with C2, 3 KFS.
Objective To observe the effects of co-transfection of Nogo extracellular peptide residues 1-40 (NEP1-40) and neurotrophin 3 (NT-3) genes with Schwann cell-derived exosomes (SCDEs) on the survival and differentiation of neural stem cells (NSCs), and lay the foundation for the in vivo experiments of SCDE and NSC co-transplantation. Methods The NEP1-40 and NT-3 genes were transfected into Schwann cells by lentiviral vector, and SCDEs were collected for identification. The NSCs that have been passaged for 3 times were selected and inoculated into the inoculation plate, and they were divided into conventional culture group, simple exosome culture group (adding empty vector plasmid to modify SCDE for culture) and two genes exosome culture group (adding two genes modified SCDE for culture). The activity of cells in each group was detected. The survival and differentiation of NSCs were evaluated by immunofluorescence detection of neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP) and galactosylceramidase (GALC) positive cells. Results After transfection of these two genes, the fluorescence intensity was higher and the cell state was better. The relative expression levels of messenger RNA and protein of NEP1-40 and NT-3 in the two gene groups were higher than those in the empty plasmid group (P<0.05). The relative expression levels of NEP1-40 and NT-3 proteins in SCDE of the two gene groups were higher than those of the empty vector group (P<0.05). There was no significant difference in the relative expression level of CD63 protein in SCDE between the two groups (P>0.05). In terms of cell activity, the cell activity of the two genes exosome culture group was the strongest, followed by the simple exosome culture group, and the conventional culture group was the weakest. The differences between any two groups were statistically significant (1.28±0.04 vs. 0.72±0.09 vs. 0.41±0.04, P<0.05). In terms of cell survival, NeuN-positive cells (5.23±0.22 vs. 2.36±0.09 vs. 1.00±0.01) and GALC-positive cells (2.29±0.06 vs. 1.75±0.02 vs. 1.00±0.04) of the two genes exosome culture group were the best, followed by the simple exosome culture group, and the conventional culture group were the weakest. The differences between any two groups were statistically significant (P<0.05). In terms of cell differentiation, NeuN-positive cells (0.44±0.02 vs. 0.29±0.01 vs. 0.16±0.01) and GALC-positive cells (0.38±0.07 vs. 0.23±0.02 vs. 0.12±0.01) of the two genes exosome culture group were the best, followed by the simple exosome culture group, and the conventional culture group were the weakest. The differences between any two groups were statistically significant (P<0.05). The differentiation of GFAP-positive cells in the conventional culture group was the best, followed by the simple exosome culture group, and the two genes exosome culture group was the worst (0.52±0.05 vs. 0.42±0.03 vs. 0.30±0.09). The differences between any two groups were statistically significant (P<0.05). Conclusion NEP1-40 and NT-3 genes can be successfully transfected into Schwann cells by lentiviral vector, which can effectively increase the content of related proteins in SCDE, and the exosomes can effectively promote the survival and differentiation of NSCs in vitro.
ObjectiveTo compare the predictive abilities of O-C2 angle (O-C2a), O-EA angle (O-EAa), and Oc-Ax angle (Oc-Axa) for development of dysphagia in patients after occipitocervical fusion (OCF).MethodsBetween April 2010 and May 2019, 114 patients who underwent OCF and met the selection criteria were selected as the research objects. Among them, 54 were males and 60 were females; they were 14-76 years old, with an average of 50.6 years old. The follow-up time was 13-122 months (median, 60.5 months). The O-C2a, O-EAa, Oc-Axa, and the narrowest oropharyngeal airway space (nPAS) were measured by the lateral X-ray films before operation and at last follow-up, and the differences before and after operation (dO-C2a, dO-EAa, dOc-Axa, and dnPAS) were calculated. Patients were divided into two groups according to whether they had developed postoperative dysphagia. The general data including age, gender, fixed segment, proportion of patients with rheumatoid arthritis (RA), atlantoaxial subluxation (AS), and combined with anterior release surgery (ARS), and imaging indicators were compared between the two groups. The correlations between dO-C2a, dO-EAa, and dOc-Axa and dnPAS in 114 patients were analyzed to further compare the predictive value of three imaging indicators for occurrence of dysphagia after OCF.ResultsDysphagia occurred after OCF in 31 cases with the incidence of 27.2%. There was significant difference in gender between the dysphagia group and the non-dysphagia group (χ2=7.940, P=0.005). There was no significant difference between the two groups in age, fixed segment, the proportion of patients with RA, the proportion of patients with AS, and the proportion of patients combined with ARS (P>0.05). There was no significant difference in O-C2a and Oc-Axa of 114 patients before operation and at last follow-up (P>0.05). The differences in O-EAa and nPAS were significant (P<0.05). There was no significant difference in preoperative O-EAa, Oc-Axa, and nPAS between the dysphagia group and the non-dysphagia group (P>0.05); the difference in the O-C2a was significant (t=2.470, P=0.016). At last follow-up, the differences in the above imaging indicators were significant (P<0.05). There were significant differences in the dO-C2a, dO-EAa, dOc-Axa, and dnPAS between the two groups (P<0.05). Correlation analysis showed that the dO-C2a, dO-EAa, dOc-Axa were all positively correlated with dnPAS (P<0.05). The dO-C2a≤−5°, postoperative O-EAa≤100°, postoperative Oc-Axa≤65° were all related to postoperative dysphagia (P<0.05), and the highest risk factor suffering postoperative dysphagia was dO-C2a ≤−5° with a significant OR of 14.4.ConclusionThe dO-C2a, postoperative O-EAa, and postoperative Oc-Axa can be used as the predictive indexes of dysphagia after OCF, among which dO-C2a has the highest predictive value.