Objective:To investigate the anatomical safety and feasibility ofposterior occipitocervical fixation with atlan-tooccipital-clivus screw.Methods:Data of 60 patients who treated in the spinal department of our hospital with upper cervical computed tomographic scans from February 2017 to November 2019 were retrospectively collected. Occipitocervical infection, injury, tumor and deformity were excluded. The Mimics software was used to reconstruct the occiput, atlas and measure the anatomical parameters, including the height and width of the anterior edge of the clivus, the height and width of the middle part of the clivus, the thinnest distance of the soft tissue in front of the clivus, the anteroposterior diameter, transverse diameter, the angle of inside tilting in coronary plane of the occipital condyle, the distance from the hypoglossal canal to the atlantooccipital articular surface, the anteroposterior diameter and transverse diameter of the superior joint of atlas, the height of the lateral mass, and the height and transverse diameter of the inferior articular process of the superior atlas joint. The three-dimensional digital modeling was performed and the screw diameter of 3.5mm was simulated. 3-Matic software were used to measure the screw placement parameters, including the inside tilting angle in coronary plane of screw, and the angle of upper tilting in sagittal plane and length of screw. The atlanto-occipital junction was exposed at the rear of 8 cadavers. According to the above parameters, the titanium alloy screws with a diameter of 3.5 mm were transferred from the inferior articular process and posterior arch of the atlas to the clivus through the atlantooccipital. Finally, the screw path was cut along the nail path with a pendulum saw, and the track of the screw was observed to confirm the safety and effectiveness of the screw.Results:The leading edge height and width of male clivus was 16.8±2.5 mm and 20.1±3.1 mm. The middle part of the clivus was 9.7±2.3 mm and 22.4±3.7 mm. The thinnest soft tissue in front of the clivus was 5.8±1.48 mm. The anteroposterior diameter of the occipital condyle was 19.1±1.9 mm, the transverse diameter was 12.6±2.0 mm, the inside tilting angle was 33.7°±4.5°, and the vertical distance from the lowest point of the neural tube to the articular surface of the occipital condyle was 9.6±1.1 mm. The height of the lateral mass of atlas was 12.9±2.4 mm, the anteroposterior diameter of the upper joint of atlas was 21.7±1.9 mm, and the transverse diameter was 11.7±1.4 mm. The width of the inferior facet was 14.9±1.4 mm and the height of the inferior facet was 5.7±0.85 mm. The distance from the screw entry point to the vertical line of the lateral mass migration midpoint was 2.5±0.6 mm; The distance from the screw entry point to the horizontal line of the midpoint was 2.3±0.7 mm.The inside titling angle of screw was 18.4°±1.6°, the upper tilting angle was 55.6°±3.1°, the length of the screw track was 53.0±2.8 mm, the adjustment range of upper tilting angle was 15.0±2.8 mm, the adjustment range of inside tilting angle was 10.4±2.4 mm. The anatomical parameters of females were slightly smaller than those of males, and the difference was statistically significant, but there was no significant difference between left and right parameters. The screws of 8 specimens could be inserted safely and effectively.Conclusion:Atlan-tooccipital-clivus screw can be implanted without damaging the nerve and vascular structure, and it can be used as a choice for occipitocervical fixation.

Objective:To provide a theoretical basis for the clinical application of the posterior route through atlas occipital articular slope screw internal fixation system through the biomechanical study.Methods:Eight cadavers of healthy adults aged 35-60 years and 155-180 cm in height were selected. The specimens with complete anatomical structure and without surgical operation were established as normal models. The model of occipito-atlantoaxial complex was established by breaking the articular capsule, ligament and other connecting structures and cutting the dentate process. The device was established as an internal fixation model through the specimen of atlantooccipital joint slope screw internal fixation system. Given normal model and internal fixation of 1.5 N·m in the moment of flexion, lateral bending and axial rotation and to measure the specimen C 0-C 1 and C 0-C 2 segment of the range (range of motion, ROM), comparative analysis of pillow neck area within the normal model and fixed model changes the range of movement, after the evaluation through the slope between atlas and the occipital screw internal fixation system of mechanical properties. Results:In the normal model, the flexion, flexion and extension, lateral bend and axial rotation ranges of C 0-C 1 segments were 23.85°±2.43°, 4.74°±0.55°, 5.77°±0.75°, respectively; the corresponding activity ranges of C 0-C 2 segments were 30.66°±3.05°, 9.09°±1.37°, 70.97°±9.48°, respectively; in the internal fixation model, the flexion and extension, lateral bend and axial rotation ranges of C 0-C 1 segments were 0.71°±0.24°, 0.24°±0.06°, 0.34°±0.09°, respectively. The corresponding activity range of C 0-C 2 segment was 3.09°±0.82°, 0.74°±0.07°, 1.22°±0.10°, respectively. Compared with the normal model, the range of activity of the internal fixation model in all directions was significantly reduced (<3°), and the reduction ratio of activity was more than 90%. Conclusion:The posterior route through pillow slope screw internal fixation system can effectively reduce the range of motion of the occipital neck in flexion, extension, lateral bending and rotation, and has safe and reliable biomechanical stability.

Objective:To explore the difference in properties of anterior occipital condyle plate screws compared with common anterior occipitalcervical fusion internal fixation.Methods:A 28-year-old healthy adult male volunteer's CT data of the occiput and neck was selected to establish finite element models：including the normal model，simple artificial vertebral fixation model（special-shaped titanium cage+clival screws），anterior occipital condyle plate and screw fixation model，and clival plate and screw fixation model，then a 50 N gravity and a torque of 1.5 N m were exerted upon the upper surface of the occipital bone to make the model produce flexion and extension，lateral bending and rotation. The motion range，internal fixation stress distribution and occipital bone stress distribution of each model under varying conditions were compared.Results:Under the conditions of flexion，extension，lateral bending and rotation，the range of motion of the normal model was 18.65°，15.35°，9.82° and 34.68°，respectively；that of the simple artificial vertebral fixation model was 3.20°，3.63°，2.94° and 3.92°，respectively；that of the clival plate and screw fixation model was 0.40°，0.50°，0.35° and 0.89°，respectively；that of the anterior occipital condylar plate and screw fixation model was 0.27°，0.33°，0.13° and 0.30°，respectively. Compared with the simple artificial vertebral fixation model，the range of motion of the clival plate and screw fixation model decreased by 87.5%，86.2%，88.1% and 77.3% in flexion，extension，lateral bending and rotation. The range of motion of the anterior occipital condylar plate and screw fixation model decreased by 91.5%，90.1%，95.6% and 92.3%，respectively. Under the conditions of flexion and extension，lateral bending and rotation，the stress peak of the simple artificial vertebral fixation model was 52.3 MPa，51.9 MPa，52.6 MPa，respectively；that of the clival plate and screw fixation was 100.1 MPa，158.1 MPa，170.6 MPa，respectively；that of the anterior occipital condylar plate and screw fixation was 114.2 MPa，62.9 MPa，132.9 MPa，respectively. Under the condition of flexion and extension，lateral bending and rotation，the stress peak of the occipital bone in the simple artificial vertebral body internal fixation model was 52.9 MPa，50.9 MPa and 62.3 MPa，respectively；that of the clival plate and screw fixation model was 19.7 MPa，55.9 MPa and 38.3 MPa，respectively；that of the anterior occipital condylar plate and screw fixation model was 37.8 MPa，15.0 MPa and 16.3 MPa，respectively. The stress in bone near the hypoglossal canal was close to 0 MPa，much smaller than the stress peak in occipital bone.Conclusion:Anterior occipital condylar plate and screw fixation in front of the special-shaped titanium cage can improve the stability of occipitocervical fusion with little effect on the occipital bone and hypoglossal canal or without obvious stress concentration，and hence is a safe and reliable anterior fixation method for upper cervical spine instability.

BACKGROUND: Even though there is bidirectional association between hypertension and atherosclerosis, atherosclerosis itself is involved in the process of endothelial repair. To clarify the association of endothelial repair with hypertension, a cross-sectional study was conducted. METHODS: We conducted a cross-sectional study of 562 elderly Japanese men aged 60-69. As gamma-glutamyl transpeptidase (γ-GTP) could act as a marker of oxidative stress that injures endothelial cell and higher levels of CD34-positive cell indicate a higher activity of endothelial repair, we therefore performed a CD34-positive level specific analysis of γ-GTP on atherosclerosis and hypertension. RESULTS: In the present study population, hypertension was independently and positively associated with atherosclerosis (multivariable odds ratio (OR) = 2.09 (1.30, 3.35)). Among participants with high CD34-positive cells, γ-GTP showed significant and positive association with atherosclerosis (OR of the log-transformed value of γ-GTP (OR) = 2.26 (1.32, 3.86)) but not with hypertension (OR = 0.77 (0.51, 1.17)). Among participants with low CD34-positive cells, even γ-GTP showed no significant association with atherosclerosis (OR = 0.92 (0.51, 1.68)), but was significantly and positively associated with hypertension (OR = 1.99 (1.27, 3.12)). CONCLUSIONS γ-GTP revealed to have ambivalent association with hypertension and atherosclerosis. Active endothelial repair that is associated with atherosclerosis might have beneficial association with hypertension.

BACKGROUND: Hypertension and atherosclerosis are bidirectionally related, while platelet count could serve as an indicator of endothelial repair. Therefore, high platelet counts could be associated with hypertension by indicating more intense endothelial repair activity. Furthermore, short stature has been shown to constitute a risk of atherosclerosis. Since inflammation-related single-nucleotide polymorphism (SNP (rs3782886)) is reportedly associated with myocardial infarction and short stature, rs3782886 could be associated with a high platelet count and thus more intense endothelial repair activity. METHODS: We conducted a cross-sectional study of 988 elderly Japanese who participated in a general health check-up. Short stature was defined as a height of at or under the 25th percentile of the study population, and high platelet count as the highest tertiles of the platelet levels. RESULTS: High platelet counts were found to be independently and positively associated with hypertension while rs3782886 was independently associated with high platelet levels and short stature. The classical cardiovascular risk factor-adjusted odds ratio (OR) and 95% confidence interval (CI) of high platelet count for hypertension was 1.34 (1.02, 1.77). With non-minor homo of the rs3782886 as the reference group, the adjusted OR and 95% CI for high platelet count and short stature of minor home were 2.40 (1.30, 4.42) and 2.21 (1.16, 4.21), respectively. CONCLUSION SNP (rs3782886) was shown to be associated with high platelet count and short stature. This result partly explains how a genetic factor can influence the impact of height on endothelial repair.
Aged ; Aged, 80 and over ; Blood Platelets ; metabolism ; Body Height ; genetics ; Cross-Sectional Studies ; Endothelium, Vascular ; physiology ; Female ; Genetic Association Studies ; Genetic Predisposition to Disease ; Genotype ; Humans ; Hypertension ; blood ; epidemiology ; genetics ; Male ; Middle Aged ; Odds Ratio ; Platelet Count ; Polymorphism, Single Nucleotide

BACKGROUND: Hemoglobin concentration reportedly is positively associated with muscle strength, for example, handgrip strength. However, hemoglobin cannot repair muscle directly, but is beneficial only in a supportive role. Since hepatocyte growth factor (HGF) regulates muscle satellite cell production and differentiation, which is stimulated by organ injury, the supportive effect of hemoglobin should thus be stronger for participants with high HGF than for those with low HGF. However, the association between hemoglobin concentration and handgrip strength in relation to HGF levels remains unknown. METHODS: We conducted a cross-sectional study of 255 Japanese elderly men aged 60-69 years who participated in annual health check-ups in 2014-2015. The study population was categorized on the basis of a median value of HGF of 300.6 pg/mL. RESULTS: Among present study population, 128 participants showed low HGF. For participants with low HGF, hemoglobin concentration showed no significant association with handgrip strength (standardized parameter estimate (β) = 0.03, p = 0.767), but for those with high HGF, hemoglobin concentration was significantly positively associated with handgrip strength (β = 0.23, p = 0.014). CONCLUSIONS A significant positive association between hemoglobin level and handgrip strength was established for elderly Japanese men aged 60-69 years with high HGF but not for participants with low HGF. Our finding indicates that HGF levels could determine the relationship of hemoglobin concentration with handgrip strength in elderly Japanese men aged 60-69 years. This result can be expected to serve as an effective tool for the clarification of the roles played by HGF and hemoglobin concentration in maintenance of muscle strength.
Aged ; Cross-Sectional Studies ; Hand Strength ; physiology ; Hemoglobins ; metabolism ; Hepatocyte Growth Factor ; genetics ; metabolism ; Humans ; Japan ; Male ; Middle Aged

BACKGROUND: Human T cell leukemia virus type-1 (HTLV-1) stimulates inflammation activity. Our previous study revealed a positive association between asymptomatic HTLV-1 infection and advanced periodontitis among elderly Japanese individuals with low levels of hematopoietic activity (reflected by reticulocyte levels). Since low hematopoietic activity has been correlated with low-grade inflammation and low-grade inflammation is associated with atherosclerosis, the status of atherosclerosis could, in turn, determine the nature of this association. METHODS: To this end, a cross-sectional study of 907 elderly Japanese individuals (aged 60-99 years), who had participated in dental health check-up during the period 2016-2018, was conducted. Advanced periodontitis was defined as periodontal pocket ≥ 6.0 mm. RESULTS: Among the study population, 295 (32.5%) were found to have atherosclerosis defined as a carotid intima-media thickness (CIMT) of ≥ 1.1 mm. HTLV-1 infection was positively associated with advanced periodontitis in participants with atherosclerosis, but no significant associations were observed among the participants without atherosclerosis. The known risk factors' (including reticulocyte and CIMT) adjusted odds ratio (OR) and 95% confidence interval (CI) of advanced periodontitis were OR 2.01 and 95% CI 1.06-3.81 for participants with atherosclerosis and OR 0.61 and 95% CI 0.34-1.12 for participants without atherosclerosis. CONCLUSION This study found a significant association between HTLV-1 infection and advanced periodontitis among elderly Japanese with atherosclerosis. However, this association is absent in individuals without atherosclerosis, suggesting that atherosclerosis might act as a determinant in the association between HTLV-1 infection and advanced periodontitis among elderly Japanese.

BACKGROUND: We reported that human T cell leukemia virus 1 (HTLV-1) infection is positively associated with atherosclerosis. Recent evidence has revealed a close association of periodontitis with atherosclerosis, endothelial dysfunction, and disruption of the microcirculation. However, the association between HTLV-1 and advanced periodontitis has not been investigated to date. Since hematopoietic activity is closely linked to endothelial maintenance activity and is known to decline with age, we hypothesized that the state of hematopoietic activity influenced the association between HTLV-1 and advanced periodontitis in elderly participants. METHODS: A cross-sectional study was performed including 822 elderly participants aged 60-99 years who participated in a dental health check-up. Advanced periodontitis was defined as a periodontal pocket ≥ 6.0 mm. Participants were classified as having low or high hematopoietic activity according to the median values of reticulocytes. RESULTS: HTLV-1 infection was positively related to advanced periodontitis among participants with lower hematopoietic activity (lower reticulocyte count), but not among participants with higher hematopoietic activity (higher reticulocyte count). The adjusted odds ratio (95% confidence interval) considering potential confounding factors was 1.92 (1.05-3.49) for participants with a lower reticulocyte count and 0.69 (0.35-1.36) for participants with a higher reticulocyte count. CONCLUSIONS Among elderly participants, the association between HTLV-1 infection and advanced periodontitis is influenced by hematopoietic activity. Since hematopoietic activity is associated with endothelial maintenance, these findings provide an efficient tool for clarifying the underlying mechanism of the progression of periodontitis among elderly participants.
Aged ; Aged, 80 and over ; Cross-Sectional Studies ; Female ; HTLV-I Infections ; physiopathology ; Hematopoiesis ; physiology ; Human T-lymphotropic virus 1 ; physiology ; Humans ; Japan ; epidemiology ; Male ; Middle Aged ; Odds Ratio ; Periodontitis ; epidemiology ; virology ; Prevalence ; Risk Factors