Prevalence of Bovine Viral Diarrhea Virus in Ovine and Caprine Flocks: A Global Systematic Review and Meta-Analysis.

Background: Bovine viral diarrhea virus (BVDV) is the causative agent of bovine viral diarrhea. It can infect cattle, sheep, pigs, and other animals, causing diarrhea, miscarriage, and stillbirth, among other symptoms, and it can result in huge economic losses to animal husbandry. There are reports on BVDV infection rates in sheep and goat herds from all over the world and this meta-analysis aimed to evaluate the prevalence of and risk factors for BVDV in sheep and goats. Results: Using the data of 41,297 sheep and goats in 24 countries/regions to calculate a comprehensive prevalence rate for BVDV. The overall prevalence of BVDV infection in sheep and goats was estimated to be 8.6% (95% CI: 5.2-12.7) by immunological methods and 7.3% (95% CI: 2.7-13.7) by molecular methods. Analysis by national income level revealed that prevalence is higher in middle-income countries than in high-income countries (P < 0.05). The study also compared prevalence rates by species of BVDV, sampling year, and test species, but did not find significant differences. Conclusion: This systematic review and meta-analysis is the first to determine the global prevalence of BVDV in ovine and caprine flocks. The prevalence of BVDV in sheep and goat populations varies from region to region, and the situation is not optimistic in some countries.

Prevalence and risk factors of bluetongue virus infection in sheep and goats in China: A systematic review and meta-analysis.

Bluetongue is a viral disease transmitted by the bite of bloodsucking insects, which mainly occurs in sheep, goats, and cattle. Bluetongue is characterized by fever, leukopenia, and severe catarrhal inflammation of the oral and gastrointestinal mucosa. The present study aimed to evaluate and analyze the prevalence of bluetongue and its associated risk factors in sheep and goats in China. We collected 59 publications from 1988 to 2019 through searches at ScienceDirect, PubMed, the Chongqing VIP Chinese journal database, Wanfang database, and Chinese Web of knowledge. In these studies, a total of 123,982 sheep and goats across 7 regions of China were investigated, and the pooled prevalence of bluetongue in sheep and goats was 18.6%, as assessed using serological methods. The prevalence of bluetongue in Southern China was 30.3%, which was significantly higher than that in Northeastern China (4.7%). The prevalence of bluetongue between sheep (12.9%) and goats (28.1%) was significantly different (P < 0.05). Detection methods subgroup analysis showed that the prevalence of bluetongue was significantly higher (P < 0.05) in the others group (43.8%) than in the agar immunodiffusion (15.9%) and enzyme-linked immunosorbent assay groups (20.5%). In addition, different geographical factors (latitude range, longitude range, altitude range, average precipitation, and average temperature) could affect the prevalence. Our results suggested that bluetongue is widespread in sheep and goats, and sheep and goats in contact with insect media, such as Culicoides, or in a warm and humid environment, could have an increased prevalence of bluetongue disease. Animal disease prevention and control departments should focus on continuous monitoring of the bluetongue epidemic in sheep and goats to prevent and control outbreaks.

Prevalence and infection risk factors of bovine Eimeria in China: a systematic review and meta-analysis.

Eimeria spp. cause the disease coccidiosis, which results in chronic wasting of livestock and can lead to the death of the animal. The disease, common worldwide, has caused huge economic losses to the cattle industry in particular. This is the first systematic review and meta-analysis of the prevalence of bovine Eimeria in China. Our search of five databases including PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), Chongqing VIP, and Wan Fang for articles published up to February 29, 2020 on the prevalence of Eimeria in cattle in mainland China yielded 46 articles, in which the prevalence of cattle ranged from 4.6% to 87.5%. The rate of bovine Eimeria infection has been decreasing year by year, from 57.9% before 2000 to 25.0% after 2015, but it is still high. We also analyzed the region, sampling years, detection methods, feeding model, seasons, and species of bovine Eimeria. We recommend that prevention strategies should focus on strengthening detection of Eimeria in calves in the intensive farming model.

TITLE: Prévalence et facteurs de risque des infections des bovins par Eimeria en Chine : revue systématique et méta-analyse. ABSTRACT: Les espèces d'Eimeria provoquent la coccidiose, une maladie qui entraîne l'émaciation chronique du bétail et peut entraîner la mort de l'animal. La maladie, répandue dans le monde entier, a causé d'énormes pertes économiques à l'industrie bovine en particulier. Ceci est la première revue systématique et méta-analyse de la prévalence des Eimeria des bovins en Chine. Notre recherche dans cinq bases de données, dont PubMed, ScienceDirect, China National Knowledge Infrastructure (CNKI), Chongqing VIP et Wan Fang, pour des articles publiés jusqu'au 29 février 2020, sur la prévalence des Eimeria chez les bovins en Chine continentale, a donné 46 articles, dans lesquels la prévalence chez les bovins variait de 4,6 % à 87,5 %. Le taux d'infection des bovins par Eimeria a diminué d'année en année, passant de 57,9 % avant 2000 à 25,0 % après 2015, mais il est toujours élevé. Nous avons également analysé la région, les années d'échantillonnage, les méthodes de détection, le modèle d'alimentation, les saisons et les espèces d'Eimeria de bovins. Nous recommandons que les stratégies de prévention se concentrent sur le renforcement de la détection des Eimeria chez les veaux dans les élevages intensifs.

Seroprevalence of Brucellosis in Buffalo Worldwide and Associated Risk Factors: A Systematic Review and Meta-Analysis.

Background: Brucellosis is an important zoonotic disease caused by Brucella spp. Brucellosis is widely distributed in more than 160 or 170 countries around the world, where it poses a huge threat to animal husbandry and human health. About 150 million head of water buffalo, distributed across more than 40 countries worldwide, are kept for the purposes of service, milk, and meat. High incidence of Brucella spp. in buffalo has negatively affected dairy products and meat products. Results: We searched all research related to seroprevalence of brucellosis in water buffalo anywhere in the world in PubMed, Science Direct, SpringerLink, China National Knowledge Infrastructure, Wanfang Database, and VIP Chinese Journal Databases. A total of 26 articles published from 1985 to 2020 met the final selection criteria. The overall seroprevalence of buffalo brucellosis worldwide was 9.7%. The seroprevalence before 2010 (20.8%) (95% CI: 5.6-42.2) was much higher than the seroprevalence rate from 2010 to 2020 (4.2%) (95% CI: 1.8-7.5). Subgroup analysis by feeding mode found that the point estimate of seroprevalence in stock buffalo (11.5%) (95% CI: 3.6-23.0) was higher than that in captive buffalo (10.6%) (95% CI: 4.9-18.1). Subgroup analysis by farming mode found that the seroprevalence was higher in captive-bred buffalo (10.7%) (95% CI: 6.6-15.7) than in intensively farmed buffalo (8.5) (95% CI: 0.9-22.2). The seroprevalence in buffalo living in dry lands (6.4%) (95% CI: 2.0-12.9) is greater than that in buffalo living in wetlands (5.1%) (95% CI: 1.8-10.4) (P < 0.05). The seroprevalence in female buffalo (10.1%) (95% CI: 3.4-19.7) was higher than that in male buffalo (4.4%) (95% CI: 2.0-7.4). The seroprevalence in lactating buffalo was higher than that in buffalo of other ages (26.9%) (95% CI: 1.8-66.5). Subgroup analysis by detection method found that the seroprevalence detected by the complement fixation test (27.3%) (95% CI: 0.7-70.8) was much higher than that detected by other methods. Conclusion: The results of this meta-analysis showed that buffalo brucellosis infection is very common in buffalo herds around the world. Although the seroprevalence of brucellosis in buffalo and humans is relatively low, serious effects upon animal husbandry and public health make it necessary to take effective control and preventive measures to control the spread of this disease.

Prevalence of Chlamydia in Pigs in China from 1985 to 2020: A Systematic Review and Meta-Analysis.

Chlamydia is a small gram-negative (G-) microorganism that can be dangerous to human and animals. In this study, we conducted a systematic review and meta-analysis of Chlamydia infection in swine in China. From PubMed, ScienceDirect, Chinese Web of knowledge (CNKI), VIP Chinese journal database, and Wanfang database, we collected a total of 72 publications reported in 1985-2020. The prevalence of Chlamydia was 22.48% in China. In the sampling year subgroup, the prevalence after 2011 was the highest (26.14%). In southern China, the prevalence was 30.97%. By contrast, the prevalence in northern China was only 10.79%. Also the difference was significant (p < 0.05). In the provincial level, Hubei had the highest rate of 36.23%. Boars had a higher prevalence (29.47%). The prevalence of Chlamydia detection in pigs with reproductive disorders (21.86%) was higher than that without reproductive disorders. Among the three age groups, finishing pigs (21.43%) had the highest prevalence. The prevalence in large-scale farmed pigs (28.58%) was the highest in the subgroup of feeding methods. The prevalence in farms was 24.29%, which was the highest in the survey areas. The prevalence in spring was the highest with 40.51%. Other methods had the highest prevalence (39.61%) than enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination assay. The prevalence of Chlamydia psittaci 18.41% was lower than the prevalence of Chlamydia abortus (41.35%). We also analyzed the impact of different climate factor subgroups (rainfall, temperature, and humidity) on the probability of pigs suffering from the disease. The results showed that Chlamydia was widespread in pigs in China. We suggest that we should strengthen the detection of Chlamydia in the semen of breeding pigs and pigs with reproductive disorders, and reasonably control the environment of large-scale pig farms, so as to reduce further infection of Chlamydia in pigs.

Prevalence of bovine leukemia in 1983-2019 in China: A systematic review and meta-analysis.

Bovine leukemia is a chronic, progressive, contagious tumor disease characterized by malignant lymphoid cell hyperplasia and systemic lymphadenopathy, and is caused by bovine leukemia virus (BLV). The disease affects almost all countries and regions where livestock are raised, and may even be a potential zoonotic disease. Monitoring and early prevention of bovine leukemia is very important. Therefore, we conducted this meta-analysis, the first of its type in the country, to estimate the prevalence of bovine leukemia in 1983-2019 in China. We included a total of 35 publications reported in 1983-2019 from the PubMed, ScienceDirect, Chinese Web of Knowledge (CNKI), VIP Chinese, and Wan Fang databases. In those articles, a total of 34,954 cattle had been tested, of which 4701 were positive for BLV infection. The estimated pooled BLV prevalence was 10.0% (4701/34,954). Subgroup analysis showed that there were significant differences for sampling years, detection methods, and age. BLV prevalence was highest in the following subgroups: sampled before 1985 (38.5%, 437/1134), age 3-5 years (22.5%, 231/1044), and detected by PCR (17.9%, 1228/5100). Regarding geographic factors, there were significant differences in the latitude and elevation subgroups. BLV prevalence was lowest in the subgroups of 20-30° latitude (3.3%, 255/5069) 200-1000 m altitude (2.2%, 560/11,990). We also analyzed other subgroups such as region, variety, breeding method, precipitation, humidity, and temperature, however, the differences were not significant. Our research indicated that the BLV was still prevalent in some of areas in China. We recommend strengthening the testing of cattle aged >1 year and using flexible testing methods such as PCR to control the prevalence of bovine leukemia and to prevent persistent infection.

Prevalence of porcine circovirus 2 throughout China in 2015-2019: A systematic review and meta-analysis.

Porcine circovirus type 2 (PCV2) causes infectious diseases in pigs leading to considerable economic losses in the pig industry. To prevent and control PCV2 infections, is important to understand the prevalence and geographical distribution of the virus. We performed the first systematic review and meta-analysis to estimate the prevalence of PCV2 in China. From PubMed, ScienceDirect, Chinese Web of Knowledge, Wanfang, and VIP Chinese Journal, we extracted 53 studies published in China between 2015 and 2019. There were 29,051 samples, 14,230 of which were positive for PCV2. The pooled prevalence of PCV2 was 46.0%, with the highest in Northeastern China (58.1%). The highest prevalence was 86.3% in Xinjiang province. Nursery pigs had the highest prevalence of PCV2 (50.9%), and the serological test detected the highest number of cases (58.5%). PCV2 prevalence was 50.1% in intensive farms and 37.5% in extensive farms. Our findings showed that PCV2 is common throughout China. Effective control measures are necessary to reduce PCV2 infections.

Machine learning-based CT radiomics method for predicting hospital stay in patients with pneumonia associated with SARS-CoV-2 infection: a multicenter study.

BACKGROUND: The coronavirus disease 2019 (COVID-19) has become a global challenge since the December 2019. The hospital stay is one of the prognostic indicators, and its predicting model based on CT radiomics features is important for assessing the patients' clinical outcome. The study aimed to develop and test machine learning-based CT radiomics models for predicting hospital stay in patients with COVID-19 pneumonia. METHODS: This retrospective, multicenter study enrolled patients with laboratory-confirmed SARS-CoV-2 infection and their initial CT images from 5 designated hospitals in Ankang, Lishui, Lanzhou, Linxia, and Zhenjiang between January 23, 2020 and February 8, 2020. Patients were classified into short-term (≤10 days) and long-term hospital stay (>10 days). CT radiomics models based on logistic regression (LR) and random forest (RF) were developed on features from pneumonia lesions in first four centers. The predictive performance was evaluated in fifth center (test dataset) on lung lobe- and patients-level. RESULTS: A total of 52 patients were enrolled from designated hospitals. As of February 20, 21 patients remained in hospital or with non-findings in CT were excluded. Therefore, 31 patients with 72 lesion segments were included in analysis. The CT radiomics models based on 6 second-order features were effective in discriminating short- and long-term hospital stay in patients with COVID-19 pneumonia, with areas under the curves of 0.97 (95% CI, 0.83-1.0) and 0.92 (95% CI, 0.67-1.0) by LR and RF, respectively, in test. The LR and RF model showed a sensitivity and specificity of 1.0 and 0.89, 0.75 and 1.0 in test respectively. As of February 28, a prospective cohort of six discharged patients were all correctly recognized as long-term stay using RF and LR models. CONCLUSIONS: The machine learning-based CT radiomics features and models showed feasibility and accuracy for predicting hospital stay in patients with COVID-19 pneumonia.

Adjacent segment degeneration after intervertebral fusion surgery by means of cervical block vertebrae.

BACKGROUND: The prevalence of cervical block vertebrae is unknown. Furthermore, there is no consensus on the cause of adjacent segment degeneration (ASD) after cervical fusion. QUESTIONS/PURPOSES: (1) What is the incidence of cervical block vertebrae? Is there a gender difference? (2) Among cervical block vertebrae cases, is ASD related to age and segment? And what is the specific relationship? (3) What are the imaging findings and characteristics of this disease? PATIENTS AND METHODS: We retrospectively diagnosed cervical block vertebrae cases with bony fusions in any segments of the cervical spine without intervertebral fusion surgery of 33,762 patients reported from 2006 to 2011 in north China. Then the X-ray of the obtained cases were observed and counted. The primary outcome was incidence of ASD according to age and segment. The secondary outcome measures were C2-7 angle in fusion (single segment fusion of lower cervical vertebra) and control groups (randomly selected cases of non-fusion), Cobb's angle of fusion segments, and curvature of each lower cervical segment in the control group. RESULTS: A total of 218 cervical block vertebrae cases were found, with a incidence of 0.65%, and C2-3 represented the highest number of fusion segment cases. There were no significant differences in the incidence by sex. Varying degrees of degeneration in the adjacent segment was present in 112 cases (51.4%). The incidence of ASD increased with age, with the ASD growth rate reaching its peak at the age of 51-60 years (55.08%). Cervical curvature shows no significant difference between patients with cervical block vertebrae and normal individuals. The segmental curvature was lower in the fusion group than in the control group, with statistical significance achieved in fusion segments located in C4-5, C5-6, and C6-7, but not C3-4. CONCLUSIONS: Fusion segments located in C4-5, C5-6, and C6-7 are more prone to ASD than C3-4. The incidence of ASD in patients with vertebral fusion increases with age. LEVEL OF EVIDENCE: III.

A biomechanical comparison of four different fixation methods for midshaft clavicle fractures.

Clavicle fractures may occur in all age groups, and 70%-80% of clavicle fractures occur in the midshaft. Many methods for treating midshaft clavicular fractures have been reported and remain controversial. To provide some guidance for clinical treatment, 30 artificial polymethyl methacrylate models of the clavicle were sewn obliquely at the midshaft to simulate the most common type of clavicular fractures, and the fracture models were divided into five groups randomly and were fixed as follows: the reconstruction plates were placed at the superior position of the fracture model (R-S group), the reconstruction plates were placed at the anteroinferior position of the fracture model (R-AI group), the locking plates were placed at the superior position (L-S group), the locking plates were placed at the anteroinferior position (L-AI group); and the control models were unfixed (control group). The strain gauges were attached to the bone surface near the fracture fragments, and then, the biomechanical properties of the specimens were measured using the compression test, torsion test and three-point bending test. The results showed that plate fixation can provide a stable construct to help with fracture healing and is the preferred method in the treatment of clavicle fractures. The locking plate provides the best biomechanical stability when placed at the anteroinferior position, and this surgical method can reduce the operation time and postoperative complications; thus, it would be a better choice in clinical practice.

Positive effect of IGF-1 injection on gastrocnemius of rat during distraction osteogenesis.

Distraction osteogenesis (DO) is used to form new bone between bone segments to lengthen the callus. Skeletal muscles frequently fail to adapt to distraction, which causes complications. Insulin-like growth factor-1 (IGF-1) has been implicated as a central regulator of muscle repair. We hypothesized that IGF-1 injection could reduce muscle complications in DO. A total of 102 Sprague-Dawley rats received DO or did not were randomly assigned into saline, IGF-1 and normal groups. On the day before the distraction, the rats in the IGF-1 group were injected with IGF-1. The gastrocnemius muscles of the rats were harvested at the 0, 1st, 4th, 7th, and 10th days of distraction. The weight of the muscles, cross-sectional area (CSA) of the muscle fibers, collagen volume fraction (CVF), maximum limit load (MLL), maximum contraction forces, and gene expression of Akt, MyoD, myogenin, myostatin, and collagen I were analyzed. The results indicated that IGF-1 injection had increased the weights, CSA of the muscle fibers, MLL and force generation of the gastrocnemius. Also, Akt, MyoD, and myogenin were upregulated, and myostatin was downregulated in the IGF-1 group. Injection of IGF-1 could attenuate the gastrocnemius atrophy, prevent fibrosis, increase MLL, and regulate the related mRNA.

Dose intraarticular steroid injection increase the rate of infection in subsequent arthroplasty: grading the evidence through a meta-analysis.

BACKGROUND: Intraarticular steroid injections are widely used in joint arthritis. However, the data regarding an association between an increased risk for arthroplasty infection after an intraarticular steroid injection are still conflicting. We conducted a meta-analysis to evaluate the evidence from relevant studies that examine the relation between intraarticular steroid injections and infection rates in subsequent joint arthroplasty and to develop GRADE based recommendations for using the steroid before arthroplasty. METHODS: A systematic search of all studies published through August 2014 was conducted using the MEDLINE, EMBASE, OVID, ScienceDirect and Cochrane CENTRAL databases. The relevant studies that examined the relation between intraarticular steroid injections and infection rates in subsequent joint arthroplasty were identified. Demographic characteristics, infection rates and clinical outcomes were manually extracted from all of the selected studies. The evidence quality levels and recommendations were assessed using the GRADE system. RESULTS: Eight studies looking at hip and knee arthroplasties were included. Meta-analysis showed that patients with steroid injection before arthroplasty had a higher deep infection rate than patients without steroid injection (OR = 2.13, 95% CI 1.02-4.45), but no significant effect on superficial infection rate (OR = 1.75, 95% CI 0.74-4.16). The overall GRADE system evidence quality was very low, which lowers our confidence in their recommendations. CONCLUSIONS: Intraarticular steroid injections may lead to increased deep infection rates of subsequent joint arthroplasty but not the superficial infection rates. Due to the poor quality of the evidence currently available, further studies are still required.

Evaluation of the stress distribution change at the adjacent facet joints after lumbar fusion surgery: a biomechanical study.

Spinal fusion surgery has been widely applied in clinical treatment, and the spinal fusion rate has improved markedly. However, its postoperative complications, especially adjacent segment degeneration, have increasingly attracted the attention of spinal surgeons. The most common pathological condition at adjacent segments is hypertrophic degenerative arthritis of the facet joint. To study the stress distribution changes at the adjacent facet joint after lumbar fusion with pedicle screw fixation, human cadaver lumbar spines were used in the present study, and electrical resistance strain gauges were attached on L1-L4 articular processes parallel or perpendicular to the articular surface of facet joints. Subsequently, electrical resistance strain gauge data were measured using anYJ-33 static resistance strain indicator with three types of models: the intact model, the laminectomy model, and the fusion model with pedicle screw fixation. The strain changes in the measurement sites indirectly reflect the stress changes. Significant differences in strain were observed between the normal and laminectomy state at all facet joints. Significant differences in strain were observed between the normal and the pedicle screw fixation fusion state at the L1/2 and L3/4 facet joints. The increased stress on the facet joints after lumbar fusion with pedicle screw fixation may be the cause of adjacent segment degeneration.

Biomechanical analysis of four types of internal fixation in subtrochanteric fracture models.

OBJECTIVE: To compare the biomechanical properties of four types of internal fixation (proximal femoral nail [PFN], dynamic hip screw [DHS], dynamic condylar screw [DCS], and proximal femoral locking plate [PFLP]) for different types of subtrochanteric fractures. METHODS: Thirty-two antiseptic femurs were randomly divided into four groups. After internal fixation had been implanted, different types of subtrochanteric fracture models were produced and each tested under vertical, torsional and vertical damage loads. RESULTS: The stiffness ratio of PFN in each fracture model and failure load were the highest in the four groups; however, the torsional stiffness ratio was the lowest. Tension strain ratios of DHS and DCS on the lateral side became compression strain ratios with restoration of the medial fragment. The stiffness ratio of DHS was lower than PFLP in each fracture model, torsional stiffness ratio was the highest in fracture models II to V and the failure load was lower only than PFN. The stiffness ratio and failure load of DCS were both the lowest, torsional stiffness ratio was similar to PFLP's in fracture models II to V. The stiffness ratio of PFLP was only lower than PFN's in each fracture model, but the failure load was lower than DHS's. CONCLUSION: Four types of internal fixation achieve better stabilities for type I subtrochanteric fractures. PFN and PFLP produce reliable stability in type IIIA subtrochanteric fractures. If the medial buttress is restored, DCS can be considered. For type IV subtrochanteric fractures, only PFN provides stable fixation. PFLP is suitable for comminuted fractures with large fragments.

[Biomechanical study on open fracture model with plate fixation compared with closed fracture model with intramedullary nail fixation in rats].

OBJECTIVE: To compare biomechanical effect of the closed fracture model with intramedullary nail fixation and the open fracture model with plate fixation in rats. METHODS: Forty 8-week-old Spragu-Dawley male rats were divided into two groups randomly. Left femoral shaft closed fractures model was created in 20 rats, and treated with intramedullary nail. Other 20 rats received open osteotomy on the left femoral shaft, and were fixed by plate. Rats were sacrificed and draw the materials at 4, 6, 8 and 12 weeks in batch. Across section area and volume of callus were measured, peak load, restoration rate of peak load were tested. The biomechanical efficency of two methods of femoral shaft fracture fixation were compared. RESULTS: The difference of surgical duration was statistically significant between two groups (P < 0.001). At 4, 6, 8 and 12 weeks, the difference of peak load, restoration rate of peak load, volume and area of callus was also statistically significant between two groups (P < 0.05). CONCLUSION: Open fracture model with plate fixation led to delayed healing compared with closed fracture model with intramedullary nail. However, open fracture model with plate fixation model could be a valuable research tool to study the healing consequences of cortical bone, which may provide insight into the pathogenesis and ideal treatment of fractures or nonunions.

A biomechanical study of the recovery in spinal stability of flexion/extension and torsion after the resection of different posterior lumbar structures in a sheep model.

Posterior lumbar structures are vital for spinal stability, and many researchers thought that laminectomy and facetectomy would lead to severe spinal instability. However, because living organisms have compensatory repair capacities, their long-term condition after injuries may change over time. To study the changes in the lumbar biomechanical stability of flexion/extension and torsion at different time points after the resection of various posterior structures, as well as to assess the capacity for self-healing, sheep that had undergone laminectomy or facetectomy were used as an experimental animal model. The injured sheep models included three groups: laminectomy only, laminectomy plus left total facetectomy, and laminectomy plus bilateral facetectomy. Eight nonoperative sheep were used as the control group. At 0, 6, 12, 24, and 36 weeks after injury, the lumbar specimens were harvested for biomechanical testing using the Instron 8874 servohydraulic biomechanical testing system. The changes in the injured lumbar spine were also analyzed through radiological examination. The lumbar stability in flexion/extension and torsion was severely decreased after the three types of surgery. After 6 weeks, the flexion/extension mechanical parameters recovered substantially; each parameter had returned to normal levels by 12 weeks and exceeded the intact group by 24 and 36 weeks. Torsional stiffness also recovered gradually over time. All injury groups demonstrated decreased intervertebral space and degeneration or even fusion in the small joints of the surgical segment or in adjacent segments. These results indicate that the body has the ability to repair the mechanical instability to a certain extent.

Risk factors for new vertebral compression fractures after percutaneous vertebroplasty: qualitative evidence synthesized from a systematic review.

STUDY DESIGN: Methodological systematic review. OBJECTIVE: To identify the risk factors for new vertebral compression fractures (VCFs) in patients after percutaneous vertebroplasty (PVP) and to grade the evidence according to the quality of included studies. SUMMARY OF BACKGROUND DATA: PVP is an effective procedure for the treatment of VCFs. A major concern after PVP in patients with osteoporosis is the occurrence of new VCFs in the untreated vertebrae. The risk factors for new VCFs after PVP reported thus far remain controversial. These risk factors have neither been well identified or summarized. This systematic review was performed to identify the risk factors for new VCFs after PVP. METHODS: Noninterventional studies evaluating the risk factors for new VCFs of patients with osteoporosis after PVP were searched in MEDLINE, EMBASE, ScienceDirect, and OVID databases (all up to November 2012). Only observational studies with eligible data were included. Quality of included studies was assessed by a modified quality assessment tool, which was previously designed for observational study. The effects of studies were combined with the study quality score using a model of best-evidence synthesis. RESULTS: Twenty-four observational studies involving 3789 patients were included. These articles were published between 2004 and 2012. According to the quality assessment criteria for included studies, 8 studies were deemed as high-quality studies, 6 as moderate-quality studies, and 10 as low-quality studies. There were strong evidences of 3 risk factors, including lower bone mineral density, lower body mass index, intradiscal cement leakage, and vertebral height restoration. We also identified 6 moderate-evidence factors including lower body mass index, number of pre-existing vertebral fractures, thoracolumbar junction in initial VCFs, cement distraction, older age, and number of treated vertebrae. Thirteen factors were classified into the limited-evidence risk factors. CONCLUSION: Although there is no conclusive evidence for new VCFs of patients with osteoporosis after PVP procedure, these data provide evidence to guide the surgeon and develop optimal preventions for new VCFs after PVP. Special attention should be paid to the 3 strong-evidence risk factors. Further studies were still required to evaluate the effects of the earlier mentioned risk factors. LEVEL OF EVIDENCE: 2.

A methodological, systematic review of evidence-based independent risk factors for surgical site infections after spinal surgery.

OBJECTIVE: To identify the independent risk factors, based on available evidence in the literature, for patients developing surgical site infections (SSI) after spinal surgery. METHODS: Non-interventional studies evaluating the independent risk factors for patients developing SSI following spinal surgery were searched in Medline, Embase, Sciencedirect and OVID. The quality of the included studies was assessed by a modified quality assessment tool that had been previously designed for observational studies. The effects of studies were combined with the study quality score using a best-evidence synthesis model. RESULTS: Thirty-six observational studies involving 2,439 patients with SSI after spinal surgery were identified. The included studies covered a wide range of indications and surgical procedures. These articles were published between 1998 and 2012. According to the quality assessment criteria for included studies, 15 studies were deemed to be high-quality studies, 5 were moderate-quality studies, and 16 were low-quality studies. A total of 46 independent factors were evaluated for risk of SSI. There was strong evidence for six factors, including obesity/BMI, longer operation times, diabetes, smoking, history of previous SSI and type of surgical procedure. We also identified 8 moderate-evidence, 31 limited-evidence and 1 conflicting-evidence factors. CONCLUSION: Although there is no conclusive evidence for why postoperative SSI occurs, these data provide evidence to guide clinicians in admitting patients who will have spinal operations and to choose an optimal prophylactic strategy. Further research is still required to evaluate the effects of these above risk factors.