Objective To summarize the research progress on rodent models of cervical spinal cord injury (SCI). Methods The relevant domestic and foreign literature in recent years was reviewed, the methods of establishing the rodent models of cervical SCI and the evaluation methods of behavior, imaging, neuroelectrophysiology, and histology were summarized. Results Cervical SCI involves primary and secondary injuries. Primary cervical SCI can be simulated with contusion, contusion compression, fracture dislocation, spinal cord traction, and spinal cord transection; scondary cervical SCI can be simulated with photochemical model and excitotoxicity model. Certain evaluation methods such as behavior, imaging, neuroelectrophysiology, and histology are used to evaluation during model building and research. Conclusion Different rodent models of cervical SCI have different advantages and application directions, and it is critical importance for the study of cervical SCI to establish effective animal models.
Objective To summarize the research progress of stem cell transplantation in treating spinal cord injury (SCI) at different stages based on the pathophysiological mechanism of SCI. Methods The relevant research literature at home and abroad was extensively reviewed to explore the impact of transplantation timing on the effectiveness of stem cell transplantation in treating SCI. Results Researchers performed different types of stem cell transplantation for subjects at different stages of SCI through different transplantation approaches. Clinical trials have proved the safety and feasibility of stem cell transplantation at acute, subacute, and chronic stages, which can alleviate inflammation at the injured site and restore the function of the damaged nerve cells. But the reliable clinical trials comparing the effectiveness of stem cell transplantation at different stages of SCI are still lacking. Conclusion Stem cell transplantation has a good prospect in treating SCI. In the future, the multi-center, large sample randomized controlled clinical trials are needed, with a focus on the long-term effectiveness of stem cell transplantation.
Objective To analyze the distribution of stress in the upper and lower plates of the prosthesis-bone interface, and the effect of interface pressure on osseointegration. Methods CT scanning was performed on goats at 1 week after artificial cervical disc replacement to establish the finite element model of C3, 4. The stress distribution of the upper and lower plates of the interface was observed. At 6 and 12 months after replacement, Micro-CT scan and three dimensional reconstruction were performed to measure the bone volume fraction (BVF), trabecular number (Tb. N), trabecular thickness (Tb. Th), trabecular separation (Tb. Sp), bone mineral density (BMD), bone surface/bone volume (BS/BV), and trabecular pattern factor (Tb. Pf). The C3 lower plate and C4 upper plate of 4 normal goat were chosen to made the cylinder of the diameter of 2 mm. The gene expressions of receptor activator for nuclear factor κB ligand (RANKL), osteoprotegerin (OPG), transforming growth factor β (TGF-β), and macrophage colony-stimulating factor (M-CSF) were detected by real time fluorescent quantitative PCR at immediate after cutting and at 24 and 48 hours after culture. The samples of appropriate culture time were selected to made mechanical loading, and the gene expressions of RANKL, OPG, M-CSF, and TGF-β were detected by real time fluorescent quantitative PCR; no mechanical loading samples were used as normal controls. Results Under 25 N axial loading, the stress of the upper plate of C3, 4 was concentrated to post median region, and the stress of the lower plate to middle-front region and two orbits. According to stress, the plate was divided into 5 regions. The Micro-CT scan showed that BMD, Tb.Th, BVF, and Tb.N significantly increased, and BS/BV, Tb.Sp, and Tb.Pf significantly decreased at 12 months after replacement when compared with ones at 6 months (P<0.05). At 24 and 48 hours after culture, the gene expressions of RANKL, OPG, and TGF-β were signifi-cantly higher than those at immediate (P<0.05), but no significant difference was found between at 24 and 48 hours after culture (P>0.05). The mechanical loading test results at 24 hours after culture showed that the RANKL and OPG gene expressions and OPG/RANKL ratio in C3 lower plate and C4 upper plate were significantly up-regulated when compared with controls (P<0.05), but no significant difference was shown in TGF-β and M-CSF gene expressions (P>0.05). Conclusion Domestic artificial cervical disc endplate has different pressure distribution, the stress of lower plate is higher than that of upper plate. Pressure has important effect on local osseointegration; the higher pressure area is, the osseointegration is better. Under the maximum pressure in interface, the osteoblast proliferation will increase, which is advantageous to the local osseointegration.
ObjectiveTo measure anatomical parameters related to cervical uncovertebral joint and provide data support for the design of uncovertebral joint fusion cage.MethodsAccording to the inclusion and exclusion criteria, raw DICOM data of cervical CT scan in 60 patients (30 males and 30 females, aged 39-60 years) were obtained, then the three-dimensional cervical spine model was reconstructed for anatomical measurement by using the Mimics19.0 software. The height of the uncinate process, the length of the uncinate process, the width of the uncinate process, and the length of the uncovertebral joint in the intervertebral foramen region were measured bilaterally from C3 to C7. The anterior and posterior distances between the uncinate processes were measured from C3 to C7. The height of the uncovertebral joint space, the central height of the intervertebral disc space, and the depth of the intervertebral disc space were also measured from C2, 3 to C6, 7. The mean, standard deviation, maximum, and minimum were calculated by using the SPSS22.0 statistical software for the design of uncovertebral joint fusion cage.ResultsThe height of the uncinate process, the length of the uncinate process, the width of the uncinate process, and the length of the uncovertebral joint in the intervertebral foramen region of C3-C7 and the height of the uncovertebral joint space of C2, 3-C6, 7 showed no significant difference between two sides (P>0.05). The height of the uncovertebral joint space also had no significant difference between females and males (P>0.05). The anterior distances between the uncinate processes of C3-C7 were significantly larger than the posterior distances between the uncinate processes (P<0.05), the uncovertebral joint presented a posterior cohesive shape. The central height of the intervertebral disc space in male group was slightly higher than that in female group, and the differences were significant (P<0.05) at C2, 3 and C5, 6; the depth of the intervertebral disc space in male group was significantly higher than that in female group (P<0.05). The central height of the intervertebral disc space was (4.94±0.49) mm (range, 3.81-5.90 mm), the depth of the intervertebral disc space was (15.78±1.23) mm (range, 12.94-18.85 mm), the anterior and posterior distances between the uncinate processes were (17.19±2.39) mm (range, 13.39-24.63 mm) and (10.84±2.12) mm (range, 7.19-16.64 mm), respectively. According to the results of the anatomical research, the height of the uncovertebral joint fusion cage was designed as 5, 6, 7, and 8 mm; the depth of the uncovertebral joint fusion cage was designed as 12, 13, 14, 15, and 16 mm; the width of the uncovertebral joint fusion cage was designed as 14-18 mm; and the two wings are designed as arc-shape with 2 and 3 mm in width.ConclusionThere are certain differences in the anatomical parameters of the uncovertebral joint between different segments. The uncovertebral joint fusion cage that designed based on the results of anatomical research is suitable for most patients.
ObjectiveTo explore the influence factors of anterior bone loss (ABL) after cervical disc arthroplasty (CDA) and effects of ABL on the clinical and radiographic outcomes.MethodsOne hundred and fifty-five patients who underwent single-level Prestige-LP CDA between January 2008 and December 2017 and met the inclusive criteria were enrolled in the study. Perioperative data of patients were collected. The Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), and the visual analogue scale (VAS) score were used for clinical outcomes evaluation. Radiographic parameters including cervical lordosis, C2-7 range of motion (ROM), disc angle, segmental ROM, and the lengths of the upper and lower endplates were assessed on the X-ray films. Device-related complications, including ABL, subsidence, radiographic adjacent segment pathology, and heterotopic ossification, were recorded. Univariate analysis was used to analyze the related factors, and logistic regression analysis was used to screen the influence factors. Patients were grouped according to whether ABL occurred after operation, and the differences in clinical and imaging evaluation parameters were compared.ResultsThere were 94 cases (60.6%) in the ABL group and 61 cases (39.4%) in the non-ABL group. Univariate analysis showed the significant differences in age, body mass index (BMI), and intraoperative blood loss between the two groups (P<0.05). However, there was no significant difference in gender, bone mineral density (T value), preoperative blood calcium level, preoperative blood phosphorus level, preoperative alkaline phosphatase level, operative segment, operative time, and follow-up time between the two groups (P>0.05). Multivariate analysis showed that the age and BMI were influence factors for ABL after CDA (P<0.05). The JOA score, NDI, and VAS score significantly improved in both groups at 3 months after operation (P<0.05), and the scores were further improved at last follow-up (P<0.05). There was no significant difference in JOA score, NDI, and VAS score between the two groups before and after operation (P>0.05). The preoperative cervical lordosis was significantly smaller in the ABL group than in the non-ABL group (t=−2.402, P=0.018). At last follow-up, the segmental ROM was significantly greater in the ABL group than in the non-ABL group (P<0.05), and the lengths of the upper and lower endplates were less in the ABL group than in the non-ABL group (P<0.05). No significant difference in the other radiographic parameters between the two groups were found (P>0.05). Prosthesis subsidence occurred in 5 cases (3.2%), including 3 cases in the ABL group and 2 cases in the non-ABL group; the difference between the two groups was not significant (P=1.000). Heterotopic ossification occurred in 67 cases (43.2%), including 32 cases in the ABL group and 35 cases in the non-ABL group; the difference between the two groups was significant (χ2=8.208, P=0.004). High-grade heterotopic ossification was detected in 26 cases (13 cases in the ABL group and 13 cases in the non-ABL group). Twenty-nine cases (18.7%) had radiographic adjacent segment pathology, including 15 cases in the ABL group and 14 cases in non-ABL group; the difference between the two groups was not significant (χ2=1.190, P=0.276).ConclusionThe incidence of ABL after CDA was relatively high, which mainly occurred within 3 months after operation, and no longer progressing with stable radiographic features after the first 12 months. Age and BMI were independent influence factors for ABL. ABL does not affect the clinical outcomes but may preserve more ROM of prostheses.