Sagittal slope angle of lateral atlantoaxial articulation is associated with the severity of basilar invagination with atlantoaxial dislocation and predicts reduction degree after surgery.

OBJECTIVE: To investigate (1) lateral atlantoaxial articulation (LAA) morphology in patients with basilar invagination (BI) with atlantoaxial dislocation (AAD) and healthy individuals and its relationship with the severity of dislocation and (2) the effect of the LAA morphology on reduction degree (RD) after surgery. METHODS: In this retrospective propensity score matching case-control study, imaging and baseline data of 62 patients with BI and AAD from 2011 to 2022 were collected. Six hundred thirteen  participants without occipitocervical junctional deformity served as controls. Logistic regression and receiver operating characteristic (ROC) curve were used for analysis. RESULTS: The age, BMI and sex did not differ significantly between the two groups after propensity score matching. Sagittal slope angle (SSA) and coronal slope angle (CSA) was lower and greater, respectively, in the patient group than in the control group. A negative SSA value usually indicates anteverted LAA. Regression analysis revealed a significant negative correlation between SSA and severity of dislocation. However, no relationship was found between CSA and the severity of dislocation. The multivariate logistic regression analysis revealed that minimum-SSA emerged as an independent predictor of satisfactory reduction (RD ≥ 90%). The ROC curve demonstrated an area under the curve of 0.844, with a cut-off value set at -40.2. CONCLUSION: SSA in patients group was significantly smaller and more asymmetric than that in the control group. Dislocation severity was related to SSA but not to CSA. Minimum-SSA can be used as a predictor of horizontal RD after surgery.

Correlation between Sternal Slope Angle and Primary Spontaneous Pneumothorax in Young Males, a Propensity Score Match Analysis.

It is generally accepted that primary spontaneous pneumothorax (PSP) is found mostly in tall, thin young males. However, the precise etiology of PSP is unclear. We compared some thoracic structural angles of PSPs and controls in young males to determine the predominant factor. CT data of 43 male PSPs (age 21.88 ± 5.30) and 30 controls (age 21.47 ± 5.47) were collected. The angle of thoracic vertebrae slope (∠α), sternal slope angle (∠ß), and tracheal-sternal stem angle (∠γ) were measured in the sagittal position. Carina angle (∠δ) was measured in the coronal position. After a propensity score match (PSM) of age and smoking history, the angles were comparatively evaluated. There were significant differences in all four angles between two unmatched groups, while only in three (∠ß, ∠γ, and ∠δ) after PSM was performed. The correlation between âˆ ß and PSP was most significant, and R2 was 0.456. The prediction accuracy of âˆ ß was 81.3%, OR was 1.386, 95% confidence interval was (1.095-1.754). The sternal slope angles in PSPs are greater than controls indicate the sternal slope angle is associates with the development of PSP and it could be a thoracic structural index to predict the risk of PSP occurrence. Clin. Anat. 33:605-609, 2020. © 2019 Wiley Periodicals, Inc.

Posterior tibial slope angle is associated with flexion-type Salter-Harris II and Watson-Jones type IV fractures of the proximal tibia.

PURPOSE: Flexion-type Salter-Harris (SH) II fractures of the proximal tibia, also described as Watson-Jones (WJ) IV fractures, are rare injuries reported among adolescent athletes who are close to skeletal maturity and remain elusive. Due to this classification disagreement, the various treatments range from nonoperative to operative types, and no previous studies have explained the mechanisms of injury or the source of the fracture forces. This retrospective matched case-control study aimed to identify radiological factors that are associated with the fracture forces and to elucidate the mechanisms of these injuries. METHODS: Sixteen flexion-type SH II/WJ IV fractures of the proximal tibia in 12 adolescents (12 males, mean age of 14.6 years) were retrospectively reviewed, and knee alignment on plain radiographs was assessed to compare the radiological outcomes of the operated knees (n = 7), nonoperated knees (n = 9), and uninjured contralateral knees (n = 8). The results were compared to healthy age- and sex-matched control subjects (n = 24 knees). RESULTS: With regard to the radiological outcomes, the posterior tibial slope angle (PTSA) was significantly greater in the nonoperated knees (19.0° ± 1.6°), operated knees (16.8° ± 1.3°), and uninjured knees (13.6° ± 1.3°) than in the healthy knees of the matched control subjects (9.6° ± 0.4°). The anatomical tibiofemoral angle was significantly less in the nonoperated knees (0.7° ± 0.6°) than in the healthy knees of the matched control subjects (3.7° ± 0.4°). CONCLUSIONS: These findings suggest a relationship between an increased PTSA and flexion-type SH II/WJ IV fractures of the proximal tibia, considering the deteriorating effects of an increased PTSA on knee kinematics. Adolescent active athletes with an increased PTSA and partially closed epiphysis of the proximal tibia are at risk for suffering from flexion-type SH II/WJ IV fractures of the proximal tibia until the closure of the proximal tibial epiphysis. LEVEL OF EVIDENCE: Case-control study, Level III.

Changes in posterior tibial slope angle in patients undergoing open-wedge high tibial osteotomy for varus gonarthrosis.

PURPOSE: In this study, postoperative changes in the posterior tibial slope angle and clinical outcomes following open-wedge high tibial osteotomy were evaluated. METHODS: This study included 39 knees (18 left, 21 right) of 35 patients (three male, 32 female; median age, 53 years; age range 37-64 years) with symptomatic isolated medial joint osteoarthritis who underwent open-wedge high tibial osteotomy and fixation with a Puddu plate. The patients were clinically assessed according to the Lysholm knee score, a visual analogue pain scale, and a patient satisfaction questionnaire. Radiological assessment was made according to the changes in the posterior tibial slope angle and the correlation between these changes and clinical signs. The median follow-up period was 11 years (range 7-14 years). RESULTS: Significant improvements were observed in the preoperative and postoperative clinical scores of the Lysholm knee scale, visual analogue pain scale, and patient satisfaction questionnaire (p < 0.05). Radiological assessment showed that the posterior tibial slope angle was significantly higher during the postoperative and follow-up periods (p  0.05). There was no correlation between the postoperative Lysholm scores and the increase in the posterior tibial slope angle (p = n.s.). CONCLUSIONS: We conclude that both the conventional Puddu plate design and its anteromedial plate placement are what increase the tibial slope after an opening-wedge proximal tibial osteotomy. Therefore, current new plate design may help preserve the posterior tibial slope angle. LEVEL OF EVIDENCE: IV.

Computer-assisted navigation decreases the change in the tibial posterior slope angle after closed-wedge high tibial osteotomy.

PURPOSE: The purpose of the present study was to compare the change in tibial posterior slope angle (PSA) between patients treated via computer-assisted and conventional closed-wedge high tibial osteotomy (CWHTO). It was hypothesized that a decrease in the PSA would be less in the computer-assisted group than in the conventional group. METHODS: Data on a total of 75 computer-assisted CWHTOs (60 patients) and 75 conventional CWHTOs (49 patients) were retrospectively compared using matched pair analysis. The pre- and postoperative mechanical axis (MA) and the PSA were radiographically evaluated. The parallel angle was defined as the angle between the joint line and the osteotomy surface. The data were compared between the two groups. RESULTS: The postoperative radiographic MA averaged 1.3° ± 2.6° valgus in the computer-assisted group and 0.3° ± 3.1° varus in the conventional group. The change in PSA averaged -0.8° ± 0.9° in the computer-assisted group and -4.0° ± 2.2° in the conventional group. The parallel angle averaged 0.2° ± 3.0° in the computer-assisted group and 6.2° ± 5.3° in the conventional group. CONCLUSION: Computer-assisted CWHTO using four guide pins could avoid inadvertent change in the PSA. The navigation can be used in anticipation of decreasing the risk of change in the PSA in CWHTO, especially in patients whose preoperative PSA is small. The special attention should be paid to locate the hinge axis acutely and to make the parallel proximal and distal osteotomy surfaces during CWHTO. LEVEL OF EVIDENCE: III.

Understanding ecological restoration potential: The role of water resources and slope gradient limits.

Ecological restoration is one of the most feasible ways to mitigate climate change and conserve ecosystems. However, the scope, intensity, effectiveness, and future potential of ecological restoration are restricted by unfavorable environmental conditions, especially limited water resources and complex topography. This paper proposes an assessment framework of ecological restoration potential under the coupled limits of water resources and slope gradient to quantitatively assess ecological restoration potential (ERP) under these two limiting factors. Results indicate that the current vegetation plantation in 20%, 0.19% and 32% areas of China's 31 provinces are larger, equal, and lower than the vegetation threshold permitted by local water resources respectively, which represents about 0.299 billion ha potential for additional restoration area. The ecological restoration potential under the integrated water resources and slope gradient constraints is 0.4 Pg C, less than half (47%) of the potential under the single limit of water resources (0.856 Pg C). However, this potential and China's existing carbon sink capacity related to terrestrial ecosystems is estimated to offset up to 8% of its current carbon dioxide emissions. Ecological restoration programs in areas with slope >5° will require additional economic investment to support Soil and Water Conservation programs, estimated to average about 212 trillion yuan. Succinctly, it is critical to integrate field investigations, process-based assessments and landscape design for sustainable ecological restoration. This work can provide techniques support for quantitative measurement of ecological restoration potential considering multiple limiting factors and guidance for sustainable implementation of ecological restoration programs.

Changes in Patellar Height and Tibial Posterior Slope after Biplanar High Tibial Osteotomy with Computer-Designed Personalized Surgical Guides: A Retrospective Study.

OBJECTIVE: Medial opening-wedge high tibial osteotomy (MOWHTO) is a surgical procedure to treat medial compartment osteoarthritis in the knee with varus deformity. However, factors such as patellar height (PH) and the sagittal plane's posterior tibial slope angle (PTSA) are potentially overlooked. This study investigated the impact of alignment correction angle guided by computer-designed personalized surgical guide plate (PSGP) in MOWHTO on PH and PTSA, offering insights for enhancing surgical techniques. METHODS: This retrospective study included patients who underwent 3D-printed PSGP-assisted MOWHTO at our institution from March to September 2022. The paired t-tests assessed differences in all preoperative and postoperative measurement parameters. Multivariate linear regression analysis examined correlations between PTSA, CDI (Caton-Deschamps Index), and the alignment correction magnitude. Receiver operating characteristic (ROC) curve analysis determined the threshold of the correction angle, calculating sensitivity, specificity, and area under the curve. RESULTS: A total of 107 patients were included in our study. The CDI changed from a preoperative mean of 0.97 ± 0.13 (range 0.70-1.34) to a postoperative mean of 0.82 ± 0.13 (range 0.55-1.20). PTSA changed from a preoperative mean of 8.54 ± 2.67 (range 2.19-17.55) to a postoperative mean of 10.54 ± 3.05 (range 4.48-18.05). The t-test revealed statistically significant changes in both values (p < 0.05). A significant alteration in patellar height occurred when the correction angle exceeded 9.39°. Moreover, this paper illustrates a negative correlation between CDI change and the correction angle and preoperative PTSA. Holding other factors constant, each 1-degree increase in the correction angle led to a 0.017 decrease in postoperative CDI, and each 1-degree increase in preoperative PTSA resulted in a 0.008 decrease in postoperative CDI. PTSA change was positively correlated only with the correction angle; for each 1-degree increase in the opening angle, postoperative PTS increased by 0.188, with other factors constant. CONCLUSION: This study highlights the effectiveness and precision of PSGP-assisted MOWHTO, focusing on the impact of alignment correction on PH and PTSA. These findings support the optimization of PSGP technology, which offers simpler, faster, and safer surgeries with less radiation and bleeding than traditional methods. However, PSGP's one-time use design and the learning curve required for its application are limitations, suggesting areas for further research.

Spine Alignment in Standing and Maximal Upper Limb Elevation in Baseball Players with Lumbar Spondylolysis and Those without Low Back Pain.

The changes in lumbar lordosis angle (LL) and sacral slope angle (SS) related to upper limb elevation and thoracic kyphosis angle (TK) in baseball players with spondylolysis remain unclear. Herein, we investigated baseball players with spondylolysis and those without low back pain, comparing LL and SS with upper limb elevation within and between groups and TK between groups. Baseball players with spondylolysis were enrolled as subjects, and baseball players without low back pain were enrolled as controls (n = 8 each). X-rays were obtained in the standing position and with maximal elevation position of the upper limb (elevation position). LL and SS were measured in the standing and elevated positions, and TK was measured in the standing position. LL was significantly larger in individuals with spondylolysis than controls. The SS of the control group was significantly larger in the elevated position than in the standing position, while the SS of the spondylolysis group was not significantly different between positions. SS was significantly larger in the spondylolysis group than in the control group, only in the standing position. Physical therapy for spondylolysis should focus on hyperlordosis alignment in the standing and maximal elevation positions of both upper limbs, sacral hyper-slope alignment in the standing position, and decreased sacral slope motion.

How to Choose the Appropriate Posterior Slope Angle Can Lead to Good Knee Joint Function Recovery in Total Knee Arthroplasty?

Objective: In this study, we aim to examine the effects of osteotomy under varying posterior slope angles on knee joint function recovery following knee arthroplasty. Methods: We conducted a retrospective analysis from September 2015 to September 2018 on 240 patients who underwent knee arthroplasty three years previously. The study participants were categorized based on changes in the angle of the posterior slope before and after surgery: Group 1, > 5°; Group 2, 3°-5°; Group 3, 0°-3°; Group 4, -3°-0°; Group 5, < -3°. All participants were affected with knee osteoarthritis. The Knee Society Clinical Rating System (KSS) knee function score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) knee function score, Visual Analogue Scale (VAS) pain score, and postoperative complications were measured 3 years after surgery. Results: The level of pain experienced by the patients decreased significantly than before, with pain scores ranging from 1.0-3.0, and there was a statistical difference between groups (H = 93.400, P < 0.001). The KSS score increased, with group 5 having the lowest median score of 78.0 and group 2 having the highest median score of 97.0, and there was a statistical difference between groups (H = 164.460, P < 0.001). The WOMAC score was reduced, with the median score being 24.0, 11.0, 14.0, 20.0, and 26.0, in the five groups, respectively. Group 5 had the highest score, while Group 2 had the lowest score, and there was a statistically significant difference between groups (H = 164.223, P < 0.001). No symptoms such as periprosthetic femoral fracture, prosthetic loosening, or pad wear were detected in patients postoperatively. Conclusion: Osteotomy at various posterior slope angles in total knee arthroplasty impacts postoperative knee function rehabilitation. An excessive increase or decrease in angle can have an impact on the postoperative recovery of knee function.

[Study on application of posterior tibial slope angle in anterior cruciate ligament].

Posterior tibial slope angle (PTSA) is a risk factor for anterior cruciate ligament (ACL) injury and has attracted a lot of attention, but its mechanism of action and diagnosis are still not systematically studied in the field of sports medicine. In this paper, we believe that PTSA should be measured by full-length lower extremity films and combined with multiple imaging data for comprehensive assessment to reduce errors. A large PTSA may increases risk of anterior cruciate ligament injury, so patients with more than 12 degrees of PTSA should be treated by preserving meniscus as much as possible during ACL reconstruction and combining with tibial osteotomy if necessary, which could effectively prevent risk of ligament re-injury. At the same time, gait analysis has an important reference value for preoperative pathogenic pattern and postoperative rehabilitation function, so the author believes that it will have a guiding significance for the development of individualized rehabilitation strategy based on PTSA, in order to achieve the best treatment effect.

Facet-occiput slope angle: A novel predictor of cage placement feasibility during surgery in basilar invagination patients.

Background and aim: Direct posterior reduction and manipulation of the C1-2 joints, accompanied by placement of spacers, is the state-of-the-art technique for treating basilar invagination (BI) and atlantoaxial dislocation (AAD). The hindrance of occiput to reaching up to the true atlantoaxial facets (AAF) during the surgery remains challenging for cage placement. The aim of this study was to explore an objective and precise method of measuring the effect of the hindrance of occiput to reaching up to the true AAF and cage placement during surgery. Method: We collected the clinico-imaging data of 58 patients with BI and AAD (Group A) who underwent surgery in our hospital, and 78 control cohorts (Group B) were retrieved retrospectively. We measured facet-occiput slope angle (FOSA) in midsagittal CT. Patients were positioned prone for surgery based on preoperative flexion O-C2a, and access to the true AAF was observed intraoperatively. The cut-off value of FOSA for the feasibility of cage placement in BI and AAD patients was appointed when access to the true AAF was impossible due to the hindrance of occiput during surgery. Results: The cut-off value of FOSA for the feasibility of cage placement was 34o with an area under the curve AUC of 0.800 (95 % CI: 0.672-0.928, P < 0.001) and the Youden index of 0.607. In patients with FOSA >34o, reaching up to the true AAF and 3D-printed cage placement was impossible. FOSA was negative in Group A and positive in Group B, significantly larger in females compared to males in both groups and significantly larger postoperatively in Group A. Conclusion: FOSA can objectively measure the feasibility of cage placement when the patient is positioned prone per preoperative flexion O-C2a. A FOSA >34o is contraindication for cage placement.

Visual function correlates with foveal slope, retinal and choroidal thickness on optical coherence tomography in type 2 Macular Telangiectasia.

PURPOSE: To correlate the foveal slope angle (FSA), retinal (RT) and choroidal (CT) thickness measured using optical coherence tomography (OCT) across different stages of type 2 macular telangiectasia (MacTel) with best-corrected visual acuity (BCVA). METHODS: A cross-sectional study of 182 gradable quality macular OCT images of 49 patients with type 2 MacTel was carried out. RT was measured on the Spectralis OCT machine from ETDRS (Early Treatment Diabetic Retinopathy Study) retinal thickness map and later used for calculating FSA. RT and CT were measured at 500-µm intervals up to 1500 µm from foveal centre manually. The change in RT, CT and FSA across five stages of type 2 MacTel was assessed. The measurements were correlated with BCVA. RESULTS: The FSA, RT and CT were calculated quadrantwise and stagewise. The FSA and RT showed a significant negative correlation with disease stage and BCVA (p < .05) in all four quadrants. No significant correlation was noted between CT and BCVA. Multivariate linear regression analysis identified the temporal FSA to correlate best with BCVA. CONCLUSION: BCVA correlates best with temporal FSA. Smaller the temporal FSA, poorer the vision.

[Analysis of the influence of tibial component posterior slope angle on short- and mid-term effectiveness of unicompartmental knee arthroplasty].

OBJECTIVE: To investigate the influence of tibial component posterior slope angle (TCPSA) on the short- and mid-term effectiveness of unicompartmental knee arthroplasty (UKA). METHODS: The clinical data of the patients with anterior medial knee osteoarthritis (KOA) treated by UKA between May 2014 and May 2019 were retrospectively analysed. There were 10 males and 45 females with a median age of 68 years (range, 49-83 years). The body mass index (BMI) was 27.63-52.26 kg/m 2, with an average of 40.04 kg/m 2. There were 28 cases of left knee, 21 cases of right knee, and 6 cases of double knees. The disease duration was from 7 months to 12 years, with an average of 4.33 years. Measurements of posterior tibial slope (PTS) and TCPSA were performed on the knee joint X-ray films of patients before operation and at last follow-up, respectively. According to the postoperative TCPSA, patients were divided into TCPSA<4° group (group A), 4°≤TCPSA<9° group (group B), and TCPSA>9° group (group C) with the quartile method. Baseline data such as age, gender, BMI, and affected side were compared among the 3 groups, as well as the Hospital for Special Surgery (HSS) score, visual analogue scale (VAS) score, and range of motion (ROM) before and after operation. RESULTS: All 55 patients were followed up 17-72 months, with an average of 36 months. No complication such as prosthesis loosening, infection, tibial plateau collapse, and dislocation of the meniscus pad occurred. The preoperative PTS was (7.38±3.37)°, and the postoperative TCPSA was (6.25±3.22)°, showing no significant difference ( t=1.815, P=0.074). According to postoperative TCPSA, there were 12 knees in group A, 32 in group B, and 17 in group C. There was no significant difference in age, gender, BMI, affected side, and preoperative HSS scores, ROM, and VAS scores among the 3 groups ( P>0.05). At last follow-up, the HSS scores, ROM, and VAS scores of the 3 groups significantly improved when compared with preoperative ones ( P<0.05). There was no significant difference in the difference of the above indicators before and after operation among 3 groups ( P>0.05). CONCLUSION: The patients with anterior medial KOA may have good short- and mid-term effectiveness after UKA. Among the recommended range of TCPSA, there is no significant influence on the postoperative short- and mid-term effectiveness. Long-term effectiveness need to extend the follow-up time and expand the sample size for research verification.

The composite dataset of the present-day Infralittoral Prograding Wedges (IPWs) in the inner continental shelf of the Campania region (Central-Eastern Tyrrhenian Sea).

This article reports on the dataset gathered following the census of 83 present-day Infralittoral Prograding Wedges (IPWs), surveyed on the inner continental shelf of the Central-Eastern Tyrrhenian Sea. The purpose of the census was to explore their bathymetric range and assess the observational laws governing this variability. The ensued dataset (Campania Region IPW Dataset, CRID) includes geographic, topographic and morpho-bathymetric indices, descriptive of each IPW and more, the exposure of each IPW to wave forcing (Geographical fetch, Effective fetch and extreme significant wave height, H S ). In this work, histograms contribute to describe all the variables and highlight the dominant features of each IPW. Location maps univocally links the geographic position of each IPW to the appropriate attribute record in the dataset. Further, thematic maps illustrate eight wave fields obtained by offshore-to-nearshore transformation by as many sea states scenarios with 200-year return period. Such wave fields are used as sources for significant wave height representing wave conditions over each IPW. This dataset could be implemented with new measures at a broader scale, by following analogue procedures for measurements, to enlarge the observational scale on IPWs and improve the numerical models which might eventually derive by the analysis of this dataset.

Use of a suspended and straightened knee joint position when fixing steel plates can prevent the increase in postoperative posterior tibial slope after open­wedge high tibial osteotomy.

BACKGROUND: Posterior tibial slope (PTS) increases after medial open-wedge high tibial osteotomy (OWHTO) is challenging for patients. This study aims to determine whether use of a suspended and straightened knee joint position during the fixing of steel plates can prevent an increase in the PTS after OWHTO. METHODS: This study retrospectively analyzed 112 subjects (122 knees) [34 males, 78 females; mean age 59.1 ± 6.6 (range 48-76) years; mean body mass index 28.06 ± 3.61 kg/m2] who underwent OWHTO. A total of 78 knees that were suspended and extended by placing a sterile cloth ball under the ipsilateral ankle during the fixing of steel plates comprised the suspended and straightened knee joint position (SSP) group, and 44 knees that were kept naturally straightened without placing a sterile cloth ball under the ipsilateral ankle during the fixing of steel plates comprised the naturally straightened knee joint position (NSP) group. Patients were clinically assessed according to the visual analog pain scale (VAS), the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index, the Knee Society Scores (KSS) knee and function scores, the Hospital for Special Surgery (HSS) knee scores and the Lysholm knee scores. Radiological assessment was performed according to the changes in the PTS between preoperation, 1-day postoperation, and the final follow-up periods. Ultimately, the difference in postoperative PTS changes between the two groups was statistically analyzed. The median follow-up period was 2.2 years (range 1.6-3.7 years). RESULTS: In the final follow-up period, significant improvements were observed in the clinical VAS scores, WOMAC scores, KSS knee and function scores, HSS scores and the Lysholm knee scores in both groups (P < 0.001), and no difference was found between the two groups. Radiological assessment showed that there was no statistical difference in the preoperative PTS between the two groups. The 1-day postoperative PTS and the most recent follow-up PTS were significantly greater than the preoperative PTS in the NSP group (t = - 3.213, - 6.406, all P < 0.001), but no significant increase was seen in the SSP group (P > 0.05). The increase in PTS in the NSP group was significantly greater than that in the SSP group at the 1-day postoperative (t = 2.243, P = 0.030) and final follow-up periods (t = 6.501, P < 0.001). CONCLUSIONS: For OWHTO, the use of a suspended and straightened knee joint position rather than a naturally straightened knee joint position during the fixing of steel plates could effectively prevent the increase in postoperative PTS. LEVEL OF EVIDENCE: Retrospective Study Level III.

Inclination of the small laminar slope angle leads to lumbar spinal stenosis due to hypertrophy of the ligamentum flavum.

OBJECTIVE: This study was designed to investigate the relationship between the laminar slope angle (LSA) and the lumbar disc degenerative grade, the cross-section area (CSA) of multifidus muscle, the muscle-fat index, and the thickness of the ligamentum flavum. METHODS: Retrospective analysis of 122 patients who were scheduled to undergo a lumbar operation for diagnoses associated with degenerative lumbar disease between January and December 2017. The L4-L5 disc grade was evaluated from preoperative sagittal T2-weighed magnetic resonance imaging of the lumber region; the CSA of the multifidus and muscle-fat index were measured at the L4 level, while the thickness of the ligamentum flavum was measured at the L4-L5 facet level from axis T2-weighed magnetic resonance imaging. The slope of the laminar was evaluated from preoperative three-dimensional computer tomography at the tip level of the facet joints and selected by the axis plane. Independent-sample T-tests were used to assess the association between age and measurement indices. RESULTS: Our results showed that age was positively connected with the LSA of L4 and L5 in different patients, although there was no significant difference between age and the difference of the two segment LSA. Partial correlation analysis, excluding the interference of age, revealed a strong negative relationship between the LSA of L4 and the thickness of the ligamentum flavum, irrespective of whether we considered the left or right. However, there was no correlation with lumbar disc degenerative grade, the CSA of the multifidus, and the muscle-fat index. CONCLUSION: The thickness of the ligamentum flavum showed changes with anatomical differences in the LSA, but not the lumbar disc degenerative grade, the CSA of the multifidus, and the muscle-fat index. A small change in LSA may cause large mechanical stress; this may be one of the causative factors responsible for lumbar spinal stenosis.

Effects of rainfall intensity, slope angle, and vegetation coverage on the erosion characteristics of Pisha sandstone slopes under simulated rainfall conditions.

The water loss and soil erosion in the Pisha sandstone region in the middle reaches of the Yellow River are extremely severe, leading to extremely harmful effects on the ecological environment and safety of the lower reaches. In this paper, the effects of the slope angle (20, 30, and 40°), rainfall intensity (20, 50, and 80 mm/h), and vegetation coverage (10, 30, and 50%) on the erosion characteristics of the Pisha sandstone slopes are studied using indoor-simulated rainfall tests. The results show that the infiltration into the Pisha sandstone is only 10~15%. It is found that rainfall intensity has the most significant effect on runoff, which gradually increases with increasing rainfall intensity. Vegetation significantly affects runoff reduction when the rainfall intensity is low (approximately 20 mm/h), but this effect decreases with increasing rainfall intensity. Rainfall intensity has an extremely significant effect (P < 0.01) on the sediment yield, followed by vegetation coverage, and slope angle. When the vegetation coverage is approximately 50%, the reduction in sediment yield reaches approximately 70%. Additionally, the sediment reduction benefit is more significant than the runoff reduction benefit. The presence of the eroded gullies on slopes with vegetation is less compared to that on the bare slopes. Therefore, relatively high vegetation coverage (≥ 50%) is required for soil and water conservation in Pisha sandstone area. The findings will provide some reference for Pisha sandstone conservation.

Predictors of poor outcome in cervical spondylotic myelopathy patients underwent anterior hybrid approach: focusing on change of local kyphosis.

OBJECTIVE: This study was a retrospective multivariable analysis for risk factors of poor outcome in patients who underwent anterior hybrid approach, and discussed the causes of worsening of postoperative local alignment. METHODS: A total of 86 patients with progressive spinal cord compression and local kyphosis underwent an anterior hybrid approach (ACDF+ACCF), between June 2011 and June 2017. We evaluated clinical outcome by the Japanese Orthopaedic Association (JOA) score and recovery rate. Patients were divided into two groups according to the worsening and improving of postoperative local alignment. Multivariate logistic regression analysis was applied to the evaluation of risk factors. Mann-Whitney U test, independent t test, and chi-squared test were performed for the comparison of local kyphosis between postoperative and last follow-up. RESULTS: There were twenty patients who had a recovery rate of less than 50%. Advance age, longer duration of symptoms, bigger T1 slope angle, and lower change of local kyphosis angle were significantly associated with a poor clinical outcome by multivariate logistic regression analysis. The cause of worsening of postoperative local alignment had T1 slope, C2-7 sagittal vertical axis (SVA), adjacent segment degeneration (ASD), and implant subsidence. CONCLUSIONS: The change of local kyphosis was a predictor of clinical outcome after the hybrid approach. Furthermore, postoperative ASD, implant subsidence, T1 slope, and C2-7 Cobb were associated with recurrence of postoperative cervical kyphosis.

Experimental study on the spread and burning behaviors of continuously discharge spill fires under different slopes.

This paper examines the effects of the slope on the burning and spread process of JP-4 continuous spill fires. Spill fires experiments were conducted on surfaces with different slope angles (0˚-3˚) in a rectangular trench (0.8m×6m). The spread and burning behaviors including the spread process, burning rate and flame height are recorded and analyzed. The results indicate that the whole spread process can be divided, based on the burning area variations with time, into four phases: 1) burning layer spread, 2) shrink process, 3) steady burning, and 4) extinguishment. The results also show that a large slope can increase the spread rate and as a result shorten the duration of the burning layer spread and shrink process phases. In addition, it is found that the slope has a more significant effect on the maximum spread area than the steady burning area. The steady burning rate decreases with increasing slope and the ratio of the steady burning rate of a spill fire and that of the corresponding pool fire is nearly constant. The flame height of continuous spill fires is also well predicted by an empirical model with a dimensionless heat release rate and equivalent pool diameter. The experimental data presented in the work will provide a basis for further studies of liquid fuel spill fire on an inclined surface.

Clinical features and treatment of "Non-dislocated hyperextension tibial plateau fracture".

BACKGROUND: To explore the epidemiological characteristics, clinical characteristics, treatment strategies, and clinical results of non-dislocated hyperextension tibial plateau fracture. METHOD: A total of 25 cases of non-dislocated hyperextension tibial plateau fracture patients were collected (12 males and 13 females), aged 27-79 years. Preoperative tibial plateau posterior slope angle was - 10~0° (average - 5.2°). Preoperative MRI showed 5 cases of MCL injury, 3 cases of PLC complex injury, and 2 cases of PLC + PCL injury. The change of tibial plateau posterior slope angle was more than 10° in patients with ligament injury, and the patients with a tibial plateau posterior slope angle change less than 10° had no ligament injury; 6 patients with simple column fracture had a ligament injury, 2 patients with bilateral column fracture had a ligament injury, and 2 patients with three column fracture had a ligament injury. RESULTS: Patients were followed up for 12-24 months (average 16.4 months). The operative time was 65-180 min (average 124 min), and the blood loss was 20-200 ml (average 106 ml). The plate was placed on the anterior part of tibial plateau. Evaluation of postoperative fracture reduction was as follows: 20 cases reached anatomic reduction, 5 cases reached good reduction (between 2 and 5 mm articular surface collapse), and the excellent rate of fracture reduction was 100%. The fracture healing time was 3-6 months (average 3.3 months). The postoperative knee Rasmussen score was 18-29 (average 24.9), and the postoperative knee joint mobility was 90-130° (average 118°). Two patients suffered superficial infection. CONCLUSIONS: The main imaging characteristic of "non-dislocated hyperextension tibial plateau fracture" is the change of tibial plateau posterior slope angle. The injury of single anteromedial column/anterolateral column fracture is easy to combine with "diagonal" injury, and when the tPSA changes more than 10°, it is easy to be combined with ligament injury. By reducing the joint articular surface and lower limb force line, repairing the soft tissue structure, and reconstructing the knee joint stability, we can get satisfactory results. TRIAL REGISTRATION: It was a retrospective study. This study was consistent with the ethical standards of the Second Affiliated Hospital of Zhejiang University Medical College and was approved by the hospital ethics committee and the trial registration number of our hospital was 20180145 .