[Clinical study of lumbar stability after unilateral biportal endoscopy in the treatment of degenerative lumbar diseases].

Objectives: To investigate the clinical efficacy of unilateral biportal endoscopy (UBE) in the treatment of degenerative lumbar disease (DLD) and its impact on postoperative lumbar stability. Methods: This is a retrospective case series study. A total of 109 cases of DLD treated with UBE in the Department of Orthopaedic, Beijing Chaoyang Hospital Affiliated to Capital Medical University from July 2020 to June 2022 were analyzed retrospectively. There were 47 males and 62 females, aged (53.3±8.2) years (range: 21 to 80 years). The surgical segments were single segment in 80 cases, two segments in 25 cases, and three segments in 4 cases. The low back pain and leg pain of visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score and Oswestry disability index (ODI) were evaluated before and after operation. The modified MacNab criteria were used for evaluation of the clinical consequences. Postoperative three-dimensional lumbar CT was performed to observe the preservation of the facet joints and the angle of the medial surface of the facetectomy(ß angle). At 12 months after surgery, X ray of the flexion and extension lumbar spine were reviewed. The comparison and analysis of the data were conducted using paired sample t tests or generalized estimation equations. Results: All 109 patients underwent operative procedures successfully. The operation time was (94.5±37.1) minutes (range:56 to 245 minutes), the times of X ray was 6.8±4.0 (range:4 to 16 times), and the days of hospitalization was (5.3±3.7) days (range:4 to 14 days). Complications included dural tears in 4 cases, transient lower limb numbness in 4 cases, epidural hematoma in 2 case. The follow-up time was (19.6±7.2) months (range:12 to 36 months). The postoperative low back pain VAS, leg pain VAS, JOA score and ODI were significantly improved(all P<0.05). According to the modified MacNab criteria, the excellent and good rate was 88.99%(97/109) at 12 months after surgery. One case underwent revision surgery because of recurrent lumbar disc herniation. In term of radiographic evaluation, the area of the surgical side facet joints after UBE surgery was reserved more than 60%. The ß angle was less than 90° in all patients. After 12 months of surgery, there was no surgical segment instability or spondylolisthesis by the X-ray of the flexion and extension lumbar spine. Conclusion: UBE can achieve satisfactory clinical efficacy in the treatment of DLD, and maintain the stability of the lumbar spine.

The Effect of Histogram Analysis of DCE-MRI Parameters on Differentiating Renal Tumors.

BACKGROUND: We aimed to assess the role of histogram analysis of DCE-MRI parameters for accurately distinguishing renal clear cell carcinoma from renal hamartoma with minimal fat. METHODS: Patients with renal tumors were enrolled from January 2013 to December 2015, including renal clear cell carcinoma (n = 39) and renal hamartoma (n = 10). Preoperative DCE-MR Imaging was performed, and whole-tumor regions of interest were drawn to obtain the corresponding histogram parameters, including skewness, kurtosis, frequency size, energy, quartile, etc. Histogram parameters differences between renal clear cell car-cinoma and renal hamartoma with minimal fat were compared. The diagnostic value of each significant parameter in predicting malignant tumors was determined. RESULTS: Histogram parameters of the DCE map contributed to differentiating the benign from malignant renal tumor groups. Histogram analysis of DCE maps could effectively present the heterogeneity of renal tumors and aid in differentiating benign and malignant tumors. ROC analysis results indicated that when frequency size = 1,732 was set as the threshold value, favorable diagnostic performance in predicting malignant tumors was achieved (AUC - 0.964; sensitivity - 84.6%; specificity - 100%), followed by skewness, Energy, Entropy, Uniformity, quartile 5, quartile 50, and kurtosis. CONCLUSIONS: Histogram analysis of DCE-MRI shows promise for differentiating benign and malignant renal tumors. Frequency size was the most significant parameter for predicting renal clear cell carcinoma.

Traditional Chinese medicine in thyroid-associated orbitopathy.

PURPOSE: Orbital fibroblasts (OF) are considered the central target cells in the pathogenesis of thyroid-associated orbitopathy (TAO), which comprises orbital inflammation, orbital tissue edema, adipogenesis, fibrosis, oxidative stress and autophagy. Certain active ingredients of traditional Chinese medicine (TCM) demonstrated inhibition of TAO-OF in pre-clinical studies and they could be translated into novel therapeutic strategies. METHODS: The pertinent and current literature of pre-clinical studies on TAO investigating the effects of active ingredients of TCM was reviewed using the NCBI PubMed database. RESULTS: Eleven TCM compounds demonstrated inhibition of TAO-OF in-vitro and three of them (polydatin, curcumin, and gypenosides) resulted in improvement in TAO mouse models. Tanshinone IIA reduced inflammation, oxidative stress and adipogenesis. Both resveratrol and its precursor polydatin displayed anti-oxidative and anti-adipogenic properties. Celastrol inhibited inflammation and triptolide prevented TAO-OF activation, while icariin inhibited autophagy and adipogenesis. Astragaloside IV reduced inflammation via suppressing autophagy and inhibited fat accumulation as well as collagen deposition. Curcumin displayed multiple actions, including anti-inflammatory, anti-oxidative, anti-adipogenic, anti-fibrotic and anti-angiogenic effects via multiple signaling pathways. Gypenosides reduced inflammation, oxidative stress, tissue fibrosis, as well as oxidative stress mediated autophagy and apoptosis. Dihydroartemisinin inhibited OF proliferation, inflammation, hyaluronan (HA) production, and fibrosis. Berberine attenuated inflammation, HA production, adipogenesis, and fibrosis. CONCLUSIONS: Clinical trials of different phases with adequate power and sound methodology will be warranted to evaluate the appropriate dosage, safety and efficacy of these compounds in the management of TAO.

[Genome sequence analysis of two SARS-CoV-2 virus infections in Inner Mongolia, 2022].

The target gene sequences of the novel coronaviruses obtained by sequencing were compared with the reference sequences to analyze the genetic variation of the two cases of the novel coronaviruses from Inner Mongolia Autonomous Region in 2022 and to explore the sources of infection. The results showed that the two sequences belonged to different evolutionary branches, Delta (AY.122) and Omicron (BA.1.1), respectively. hCoV-19/Inner Mongolia/IVDC-591/2022 had 48 single nucleotide polymorphisms on the genome sequences, sharing 40 nucleotide mutation sites with a Mongolian strain; hCoV-19/Inner Mongolia/IVDC-592/2022 genome shared 57 nucleotide mutation sites with a UK strain, and the nucleotide mutation site identity was 100% (57/57). Phylogenetic analysis showed that the target gene sequences were not directly related to domestic novel coronavirus sequences during the same period, but were related to isolates from Europe and Mongolia.

[Application of cortical bone trajectory screw and sacral alar screw internal fixation for surgical treatment of lumbar adjacent segment degeneration].

Objective: To explore the application of cortical bone trajectory screw (CBTS) and sacral alar screw (SAS) internal fixation in the treatment of lumbar adjacent segment degeneration (ASD) and evaluate its clinical effect. Methods: Data of 24 patients who were diagnosed with ASD and treated by CBTS or SAS in Beijing Chaoyang Hospital were retrospectively reviewed. There were 14 males and 10 females with a mean age of (67.9±8.2) years. The patients were followed-up for (2.6±0.4) years. Perioperative parameters including operation time, intraoperative blood loss and postoperative time on the ground were counted. All patients were followed-up for at least 2 years. Visual analogue scale (VAS) and the Oswestry disability index (ODI) were compared between pre-operation and at the last follow-up. The internal fixation-related complications, pseudarthrosis and adjacent re-degeneration were evaluated in the follow-up. Results: There were 14 proximal ASD patients, 8 distal ASD patients, 1 both ends ASD patient and 1 ASD patient in between the fusion surgeries. Bone mineral density (BMD) T score of the adjacent vertebrae was -1.98±0.91 on average. The ASD patients were re-operated with CBTS and SAS internal fixation technique. A small incision was made in the revision surgery and the original fixation was not completely cut open and removed. The mean operation time was (125±36) min, mean blood loss was (85±33) ml. The postoperative ambulation time was (3.1±1.9) days, and the hospitalization time was (9.0±2.6) days. Before the operation, the average VAS (back pain) score was 5.2±1.0, the average of VAS (leg pain) score was 6.8±1.9 and ODI was 56.6%±12.8%. VAS score was reduced to 1.4±0.6 (waist pain) and 0.9±0.4 (leg pain). ODI was improved to 13.8%±6.3%. All the difference between preoperative and the last follow-up was statically significant (all P<0.01). No internal fixation failure, pseudarthrosis and adjacent re-degeneration were observed in the final follow-up. Conclusion: The application of CBTS and SAS internal fixation techniques in the surgical treatment of lumbar ASD has the advantages of less trauma, faster postoperative recovery, reliable internal fixation, and fewer complications, especially in patients with low bone mineral density.

[Clinical application and prospect of lumbar cortical bone trajectory screw].

For a long time, lumbar pedicle screw fixation and fusion has been regarded as the gold standard for the treatment of the lumbar spine degenerative diseases. However, in patients with osteoporosis, pedicle screw fixation often fails to obtain long-term satisfactory. In recent years, the emergence of cortical bone trajectory screw has become an alternative option for dealing with these problems. With the development of clinical and basic research, scholars have found that cortical bone screw internal fixation can help improve fixation strength, reduce surgical trauma, and accelerate postoperative recovery. Based on the current evidence-based research and clinical application experience, this article analyzes the research hotspots of cortical bone screws, introduces the experience and pitfalls in clinical practice, and provides references for colleagues.

[Clinical application of sacral alar screw fixation in surgical treatment of lumbosacral degenerative disease].

Objective: To verify the safety and feasibility of sacral alar screw fixation and fusion surgery in lumbosacral area. Methods: The clinical and radiological data of patients receiving L5/S1 single-level cortical bone trajectory screw combined with sacral alar screw decompression fixation and fusion in Beijing Chaoyang Hospital due to lumbar spinal stenosis from January 2019 to January 2020 were retrospectively analyzed. The clinical data included operation duration, intraoperative blood loss, postoperative drainage, pain and function scores during follow-up. The radiological data included preoperative and postoperative follow-up X-rays and three-dimensional reconstruction of lumbar spine CT. The fusion status and complication of internal fixation, such as screw loosening and fixation failure were evaluated by the radiological examination. Results: According to the inclusion and exclusion criteria, a total of 16 patients (7 males and 9 females) were included, with an average age of (69.6±5.2) years. The patients were followed-up for (16.2±1.7) months. The average operation duration was (144±21) min, the intraoperative blood loss was (103±20) ml, and the postoperative drainage was (80±34) ml. The patient's low back pain visual analogue scale (VAS) score was 6.8±1.0 before surgery, and it was improved to 0.9±0.7 at the last follow-up; leg pain VAS score was 6.1±0.9 before the operation and it improved to 0.9±0.7 at the last follow-up; Oswestry disability index (ODI) function score was 66.2%±8.0% before the surgery and it decreased to 26.6%±7.2% at the last follow-up. No neurological complications, surgical site infection, screw loosening, internal fixation failure or cage displacement were observed during the follow-up. The fusion rate was 68.8% (11/16) at 6 months post operation. Conclusion: It is safe, feasible and effective to apply cortical screws combined with sacral alar screws in short-segment decompression, fixation and fusion surgery on the lumbosacral region to treat lumbosacral spinal stenosis.

[A long-term follow up study of cervical spondylotic myelopathy using diffusion tensor imaging].

Objective: To analyze the correlation between the parameters of diffusion tensor imaging (DTI) and the clinical function scores before and 5 years after anterior cervical discectomy and fusion (ACDF) by measuring the DTI signal of the maximum compression level (MCL) of the cervical spinal cord in patients with cervical spondylotic myelopathy (CSM). Methods: A prospective study was conducted and clinical data of 37 patients with CSM treated by ACDF in Beijing Chaoyang Hospital from February 2014 to February 2020 were analyzed. The MCL was studied with diffusion tensor imaging (DTI) of MRI. The changes of diffusion indexes (fractional anisotropy (FA)), and clinical function score including Modified Japanese Orthopedic Association (mJOA), neck disability index (NDI) and visual analog scale (VAS) of pain were compared among each follow-up point. The FA value and clinical function score were collected and the data was analyzed to determine whether the high signal intensity could be observed in T2-weighted imaging (T2WI) at each follow-up point. The changes of preoperative and postoperative data were compared, and the correlation between FA value and other two clinical function score were analyzed at each follow-up point. Results: There were 14 males and 23 females with a mean age of (55±10) years in this study. All patients received the surgery and the medullary symptoms improved significantly postoperatively. After 3 months, the mJOA and FA value were improved by 2.62±1.41 and 0.14±0.11 on average, respectively (both P<0.05); and there were significant differences in these two indexes between each follow-up point in two years after the operation (all P<0.05). At the MCL, there were strong correlations between the FA value and mJOA score pre-and postoperatively (rs=0.770, 0.729, both P<0.01). There was no significant correlation between mJOA, NDI and VAS (both P>0.05). Conclusions: The DTI sensitively reflects the improvement of spinal cord function and can be used as an important tool to predict and evaluate the state of spinal cord dysfunction in patients with CSM.

[The clinical effect of percutaneous curved kyphoplasty for osteoporosis vertebral compression fractures].

Objective: To evaluate the clinical effect of percutaneous curved kyphoplasty (PCK) for osteoporosis vertebral compression fractures (OVCF). Methods: This is a prospective study.Patients with OVCF who underwent PCK at the Department of Orthopedics,Beijing Chaoyang Hospital, Capital Medical University from June 2018 to June 2019 were included.All the operations were performed by the same surgeon.X-ray examination was performed before and after the operation to measure the vertebral height and Cobb angle.The visual analogue scale (VAS) and Oswestry disability index (ODI) scores were evaluated before and after the operation,and the amount of bone cement injected was record.The leakage rate and distribution of bone cement was observed by CT examination after the operation,and the postoperative complications was collected during the follow-up.Paired-t test was used to compare the related indexes before and after operation. Results: There were 32 patients in our study,including 8 males and 24 females,aged (74.9±9.9) years (range:64 to 81 years).The intraoperative bone cement injection volume was (4.2±1.5) ml(range:2 to 6 ml).According to the classification of distribution of bone cement,28 cases were rated as type Ⅰ and 4 cases were rated as type Ⅱ. Bone cement leakage was observed in 12 cases (37.5%),and there was no intraspinal leakage or venous leakage.The vertebral height was improved from (21.9±6.2) mm preoperatively to (24.3±4.3) mm postoperatively(t=-2.836,P=0.008),Cobb angle improved from(M(QR))14°(15°)preoperatively to 12.5°(12.75°)postoperatively(Z=-1.950,P=0.051),VAS improved from 6.8±0.7 preoperatively to 1.7±0.8 postoperatively (t=28.946,P<0.01),ODI score improved from 73.4±7.3 preoperatively to 21.3±5.7 postoperatively (t=32.250,P<0.01).The patients were followed up for (19.7±3.7) months (range:15 to 29 months).One patient had refracture (3.1%,1/32),and no other complications such as neurological dysfunction and pulmonary embolism occurred. Conclusions: The clinical effect of PCK in the treatment of OVCF was satisfactory.This technique could reduce the difficulty of puncture to a certain extent,and be beneficial to the distribution of bone cement.

Effect of progestogen for women with threatened miscarriage: a systematic review and meta-analysis.

BACKGROUND: Threatened miscarriage is a common complication of pregnancy. Results of randomised controlled trials on the efficacy of progestogen in the treatment of threatened miscarriage remain inconsistent. OBJECTIVE: To investigate whether the use of progestogen is associated with improved event rate of live birth and other benefits in women with threatened miscarriage. SEARCH STRATEGY: Ovid MEDLINE, Ovid Embase and Cochrane CENTRAL Register of Controlled Trials from their inception until 8 July 2019. SELECTION CRITERIA: Randomised controlled trials comparing progestogen with a placebo or no treatment for pregnancy outcomes in women with threatened miscarriage. DATA COLLECTION AND ANALYSIS: Two authors independently conducted data extraction and assessed study quality. We calculated risk ratios (RR) and 95% confidence intervals using the Mantel-Haenszel approach for dichotomous outcomes. MAIN RESULTS: Ten trials with a total of 5056 participants were eligible for analysis. The use of progesterone increased the incidence of live birth (RR 1.07, 95% CI 1.00-1.15; P = 0.04; I2  = 18%), with benefit only seen with the use of oral progestogen (RR 1.17, 95% CI 1.04-1.31; P = 0.008; I2  = 0%) and not with vaginal progesterone (RR 1.04, 95% CI 1.00-1.08; P = 0.07; I2  = 0%). Similarly, progestogen reduced the risk of miscarriage (RR 0.73, 95% CI 0.59-0.92), with benefit only seen with oral progestogen and not with vaginal progesterone. CONCLUSION: Progestogens may have benefits on live birth rate and miscarriage rate for women with threatened miscarriage. These benefits appear to be confined to the use of oral progestogen, and no statistically significant improvements were seen with vaginal progesterone. TWEETABLE ABSTRACT: A meta-analysis of 10 trials found that progestogens increased live birth rates and reduced miscarriage rates for women with threatened miscarriage.

Immunohistochemical analysis of human orbital tissue in Graves' orbitopathy.

PURPOSE: Immunohistochemistry of orbital tissues offers a correlation between the microscopic changes and macroscopic clinical manifestation of Graves' orbitopathy (GO). Summarizing the participation of different molecules will help us to understand the pathogenesis of GO. METHODS: The pertinent and current literature on immunohistochemistry of human orbital tissue in GO was reviewed using the NCBI PubMed database. RESULTS: 33 articles comprising over 700 orbital tissue samples were included in this review. The earliest findings included the demonstration of HLA-DR and T cell (to a lesser extent B cell) markers in GO orbital tissues. Subsequent investigators further contributed by characterizing cellular infiltration, confirming the presence of HLA-DR and TSHR, as well as revealing the participation of cytokines, growth factors, adhesion molecules and miscellaneous substances. HLA-DR and TSHR are over-expressed in orbital tissues of GO patients. The inflammatory infiltration mainly comprises CD4 + T cells and macrophages. Cytokine profile suggests the importance of Th1 (especially in early active phase) and Th17 immunity in the pathogenesis of GO. Upregulation of proinflammatory/profibrotic cytokines, adhesion molecules and growth factors finally culminate in activation of orbital fibroblasts and perpetuation of orbital inflammation. The molecular status of selected parameters correlates with the clinical presentation of GO. CONCLUSION: Further investigation is warranted to define precisely the role of different molecules and ongoing search for new players yet to be discovered is also important. Unfolding the molecular mechanisms behind GO will hopefully provide insights into the development of novel therapeutic strategies and optimize our clinical management of the disease.

[Change of cervical sagittal alignment after the treatment of growing rods to the early-onset scoliosis].

Objective: To determine the impact of growing rods (GR) technique on cervical alignment in early-onset scoliosis (EOS) through the change of cervical alignment parameters after the GR surgery. Methods: Total of 24 consecutive EOS patients treated in Beijing Chao-Yang Hospital from 2009 to 2018 were retrospectively reviewed (17 males and 7 females). Cervical lordosis, T(1) slope and C(2-7) sagittal vertical axis (C(2-7)SVA), thoracic/lumbar Cobb angle, thoracic kyphosis (TK), global kyphosis Cobb angle, SVA were included in radiographic data in the full spinal standing X-ray before and post operation and at the last follow-up. Based on clinical data, including the upper instrumented vertebra (UIV), proximal junctional kyphosis (PJK) and the number of GR, patients were divided into different groups for statistical analysis. Logistic regression analysis was used to find the independent risk factors of the abnormality of C(2-7)SVA. Results: All patients received at least one time of distraction operation, the mean follow-up was (35±14) months. The C(2-7) Cobb angle increased from 17°±11° to 18°±9° and T(1) slope changed from 28°±13° to 28°±11° and C(2-7)SVA changed from (17±11) mm to (16±10) mm after the operation, but no significant differences were found in those indexes before and after the operation (t=-1.15, 0.14, 0.55, all P>0.05). At the last follow-up after GR technique, the C(2-7) Cobb angle, T(1) slope angle and C(2-7)SVA significantly increased when compared with those before the operation (t=-7.60, -4.08, -2.46, all P<0.05). The △C(2-7) Cobb angle and △T(1) slope angle PJK group was both more significant than those in non-PJK group (t=3.50, 3.25, both P<0.05); while there was no significant difference in the △C(2-7) Cobb angle and △T(1) slope angle when the choice of UIV and the number of GD were taken into account (t=-1.02, -1.61, -0.67, 0.31, all P>0.05). The occurrence of PJK was identified as an independent risk factor for the abnormality of C(2-7)SVA during the GR surgery with logistic regression analysis(OR=11.57, 95%CI: 1.49-91.54, P<0.05). Conclusions: When used for EOS to correct deformity, GR surgery will increase the cervical lordosis and T(1) slope angle of EOS patients. More attention should be paid to the cervical sagittal alignment and cervical sagittal imbalance in EOS patients with PJK.

[Effect of posterior lumbar fusion on the degeneration of adjacent segments using cortical bone trajectory screw fixation].

Objective: To compare the degenerative changes of adjacent segments after posterior lumbar fusion surgery using cortical bone trajectory (CBT) screws and pedicle screws (PS) in lumbar spinal degenerative disease. Methods: According to certain inclusion and exclusion criteria, prospective non-randomized study on cases of the single-segment lumbar spinal fusion surgery using cortical bone trajectory screws fixation and pedicle screws fixation in Beijing Chao-Yang Hospital from January 2015 to February 2016 was performed. The intervertebral space height (ISH), foramen height (FH), foramen width (FW), cephalad adjacent segment (CAS) and intervertebral disc degeneration grades at MRI scans were measured before surgery and during follow-up. Clinical symptoms were evaluated by Oswestry Dysfunction Index (ODI) score and pain visual analogue scale (VAS) before and during the follow-up. Radiologic adjacent segment degeneration (R-ASD) and symptomatic adjacent segment disease (S-ASD) patients were diagnosed during the follow-up. Paired sample t test was performed when data were compared before surgery and during follow-up. Results: A total of 69 patients were included in the study, 33 in the CBT group (male/female, 15/18), with an average age of (65±11) years, and 36 in the PS group (male/female, 17/19), with an average age of (64±10) years. The follow-up time was no less than 36 months. At the last follow-up, the ISH of the adjacent segments in the CBT group were not statistically different from that before surgery; the ISH of the adjacent segments in the PS group were significantly reduced compared with that before surgery (t=6.78, P<0.05). The loss of ISH, FH, and FW in the adjacent segments in the CBT group were smaller than those in the PS group, and the differences were statistically significant. During follow-up, 4 cases (12.1%) of R-ASD and no S-ASD were found in the CBT group, while 12 cases (33.3%) of R-ASD appeared in the PS group, which was significantly higher than that in the CBT group (χ(2)=4.35, P=0.04). According to MRI, the adjacent discs of PS group had significantly more severe degeneration at the last follow-up than the CBT group (Z=-2.14, P=0.03). Conclusions: Compared with the PS fixation fusion, the CBT screw fixation can effectively reduce the occurrence of adjacent segment degeneration.

Bidirectional Mendelian randomization to explore the causal relationships between body mass index and polycystic ovary syndrome.

STUDY QUESTION: What are the causal relationships between polycystic ovary syndrome (PCOS) and body mass index (BMI)? SUMMARY ANSWER: Bidirectional Mendelian randomization analyses suggest that increased BMI is causal for PCOS while the reverse is not the case. WHAT IS KNOWN ALREADY: The contribution of obesity to the pathogenesis of PCOS is controversial. To date, published genetic studies addressing this question have generated conflicting results and have not utilized the full extent of known single nucleotide polymorphisms associated with body mass index (BMI). STUDY DESIGN, SIZE, DURATION: This cross-sectional Mendelian randomization (MR) and genetic association study was conducted in 750 individuals of European origin and with PCOS and 1567 BMI-matched controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: Cases and controls were matched for BMI as well as for distribution of weight categories (normal weight, overweight, obese). Two-sample MR using inverse variance weighting (IVW) was conducted using a 92-SNP instrument variable for BMI with PCOS as the outcome, followed by two-sample MR with a 16-SNP instrument variable for PCOS with BMI as the outcome. Sensitivity analyses included MR-Egger and maximum likelihood methods. Secondary analyses assessed associations of genetic risk scores and individual SNPs with PCOS, BMI and quantitative androgen-related and glucose homeostasis-related traits. MAIN RESULTS AND THE ROLE OF CHANCE: Each standard deviation genetically higher BMI was associated with a 4.89 (95% CI 1.46-16.32) higher odds of PCOS. Conversely, genetic risk of PCOS did not influence BMI. Sensitivity analyses yielded directionally consistent results. The genetic risk score of 92 BMI SNPs was associated with the diagnosis of PCOS (OR 1.043, 95% CI 1.009-1.078, P = 0.012). Of the 92 BMI risk variants evaluated, none were associated individually with PCOS after considering multiple testing. The association of FTO SNP rs1421085 with BMI was stronger in women with PCOS (ß = 0.071, P = 0.0006) than in controls (ß = 0.046, P = 0.065). LIMITATIONS, REASONS FOR CAUTION: The current sample size, while providing good power for MR and genetic risk score analyses, had limited power to demonstrate association of individual SNPs with PCOS. Cases and controls were not matched for age; however, this was mitigated by adjusting analyses for age. Dietary and lifestyle data, which could have been used to explore the greater association of the FTO SNP with BMI in women with PCOS, was not available. WIDER IMPLICATIONS OF THE FINDINGS: Increasing BMI appears to be causal for PCOS but having PCOS does not appear to affect BMI. This study used the most comprehensive set of SNPs for BMI currently available. Prior studies using fewer SNPs had yielded conflicting results and may have been confounded because cases and controls were not matched for weight categories. The current results highlight the potential utility of weight management in the prevention and treatment of PCOS. STUDY FUNDING/COMPETING INTEREST(S): National Institutes of Health Grants R01-HD29364 and K24-HD01346 (to R.A.), Grant R01-DK79888 (to M.O.G.), Grant U54-HD034449 (to R.S.L.), Grant U19-HL069757 (to R.M.K.). The funders had no influence on the data collection, analyses or conclusions of the study. No conflict of interests to declare. TRIAL REGISTRATION NUMBER: N/A.

[In-vivo change of the spine canal after surgical corrections of severe and rigid kyphoscoliosis].

Objective: To measure the length changes of the spine canal of patients with severe kyphosis after treatments of deformity using osteotomy surgeries. Methods: Retrospectively investigated the data of 10 severe kyphosis patients who were treated between August of 2016 and December of 2018 at Beijing Chaoyang Hospital (5 with Ponte and 5 with posterior vertebra column resection (VCR) osteotomy surgeries). For each patient, the full-spine X-Ray images were used to measure Cobb angles before and after the surgery; 3D CT images were used to construct a 3D model of the spine, including the T(2) to L(2) vertebrae and the spine canal. The 3D model was then used to measure the spinal canal lengths (SCLs) between the upper and lower vertebrae (U/LEV) and between T(2)-L(2) vertebrae at 5 locations on the spine canal cross section (anterior, central, posterior, left and right locations), and the vertical distance between the T(2) and L(2) vertebrae before and after the surgery. The data were statistically analyzed using t tests. Results: For the 5 patients of Ponte osteotomy, the Cobb angles were improved by 89°±17°(56%±11%) and 84°±16°(56%±8%) in the coronal and sagittal planes respectively after the surgery. The changes of the SCL between the T(2)-L(2) vertebrae were (9.9±4.8) mm and (6.0±12.7) mm, and those were (7.2±5.4) mm and (-0.5±7.9) mm between the U/LEV, respectively at the concave and convex sides of the canal. The vertical distance between the T(2)-L(2) vertebrae increased by (66.1±12.0) mm. For the 5 patients with VCR osteotomy, the Cobb angles improved by 83°±19°(60%±10%) and 82°±22°(56%±10%) in the coronal and sagittal planes, respectively. The changes of the SCL between the T(2)-L(2) vertebrae were (-5.5±5.3) mm and (-14.0±6.6) mm, and those were (-8.3±8.4) mm and (-20.7±11.6) mm between the U/LEV, respectively at the concave and the convex sides of the canal. The vertical distance between the T(2)-L(2) vertebrae increased by (41.5±12.4) mm. Conclusions: The Ponte osteotomy significantly elongates the SCLs, especially at the concave side, and the VCR osteotomy shortens the spinal canal, resulting in significant compression of the spinal cord at the convex side.

[Surgical results and sagittal alignment analysis of different fusion levels for degenerative scoliosis].

Objective: To retrospectively investigate the effects of long segment fusion and short segment fusion on lumbar sagittal alignment and quality of life in patients with degenerative scoliosis. Methods: From January 2011 to December 2014, 75 patients with degenerative scoliosis were treated with pedicle screw fixation. Total of 56 females and 19 males were included in this study. Fifty-four patients underwent short-segment fusion (≤3 segments) and 21 patients underwent long-segment fusion (>3 segments). The average age of the patients was (63±8) years. The patients were followed-up for a mean time of (2.9±1.3) years. The postoperative follow-up included Cobb angle, pelvic tilt, sacral slope, lumbar lordosis, visual analogue scale of pain on lumbar and lower extremities and Oswestry disability index. Fusion levels, blood loss, surgery length and postoperative hospital stay were recorded. All above parameters were evaluated statistically with Student's t test. Results: The short segment fusion group averaged (1.8±0.7) segments, and the long segment fusion group averaged (5.2±1.6) segments. Coronal Cobb angle changed from (21.3±7.8) degrees preoperatively to (15.3±5.6) degrees at final follow-up in short-segment fusion group (t=2.315, P=0.024) and from (44.5±11.2) degrees preoperatively to (11.4±5.8) degrees at the final follow-up in long-segment fusion group (t=8.214, P<0.01). In the short segment fixation group, the preoperative lumbar lordosis changed from (44.3±9.7) degrees to (48.9±8.2) degrees at final follow-up (t=2.123, P=0.038), and it changed from (25.3±9.5) degrees to (52.1±11.2) degrees in the long segment fusion group (t=5.982, P<0.01). The sacral slope in the short segment fusion group increased from (22.6±6.8) degrees preoperatively to (34.1±7.5) degrees at the final follow-up (t=2.872, P=0.006), and it increased from (12.1±9.5) degrees to (37.8±8.4) degrees in long segment fusion group (t=7.314, P<0.01). The pelvic tilt in the short segment fusion group changed from (23.5±5.5) degrees preoperatively to (19.5±4.7) degrees at final follow-up (t=2.217, P=0.031), and it decreased from (27.1±6.1) degrees to (22.9±4.3) degrees in the long segment fusion group(t=2.131, P=0.045). The visual analogue scale of pain on lumbar and lower extremities and Oswestry disability index were all improved after the operation in both groups. Conclusions: Both short segment fusion and long segment fusion can achieve satisfactory surgical results and improves the spinal-pelvic parameters. Short segment fusion can reduce surgery trauma and shorten hospital stay relative to long segment fixation.

[Comparison of cortical bone trajectory screw fixation and pedicle screw fixation in posterior lumbar fusion].

Objective: To evaluate the efficacy and safety of cortical screw fixation in posterior lumbar spine fixation with cortical bone trajectory (CBT) fixation or pedicle screw (PS) fixation in posterior lumbar fusion. Methods: It was a prospective study and CBT or PS for the treatment of lumbar disease from August 2015 to August 2017 in Beijing Chaoyang Hospital were analyzed. There were 53 males and 51 females, aged 56-78 years (mean age, (67±5) years). The patient's gender, age, operative time, intraoperative blood loss, postoperative bleeding, postoperative hospital stay, and postoperative patient satisfaction were collected. The Oswestry disability index (ODI) and visual analogue scale (VAS) of back pain were used to evaluate preoperative and half-year, one-year and two-year postoperative function and quality of life. Complications such as wound infection, cage displacement, screw extraction and fixation fracture were compared between the two groups. The data of normal distribution were compared with Student t test between the two groups. Results: There was no significant difference in the operation time between the CBT group (n=50) and the PS group (n=54) ((223±17) min vs (221±16) min, t=0.74, P=0.46). The intraoperative blood loss and wound drainage volume were significantly lower in the CBT group than those in the PS screw group (t=-24.20, -57.62, both P<0.05). The average length of hospital stay in the CBT group was significantly shorter than that in the PS group (t=-7.65, P=0.00). Patients with CBT screws had better postoperative satisfaction than patients in PS group (91±6 vs 86±7, t=3.89, P=0.00). The ODI score in the CBT group was significantly lower than that in the PD screw group half a year after the operation (3.9±1.9 vs 5.8±3.1, t=-3.66, P=0.00). The VAS and ODI scores in the CBT group were significantly lower than those in the PS group 1 year after the surgery (t=-3.03, -4.09, both P<0.05). There was no significant differences in wound infection, cage displacement, screw extraction and fixation fracture between the two groups. Conclusion: CBT screw technique is minimally invasive, with short operation time, less intraoperative blood loss, rapid postoperative recovery and low complications. It can be effectively used in posterior lumbar cone fusion.

[Percutaneous endoscopic transforaminal lumbar interbody fusion for lumbar spinal stenosis].

Objective: To evaluate the clinical effects of percutaneous endoscopic transforaminal lumbar interbody fusion (PE-TLIF) for L(4/5) single-segment lumbar spinal stenosis. Methods: From September 2016 to March 2018, 7 patients with L(4/5) single-segment lumbar spinal stenosis were treated by PE-TLIF in the Department of Orthopedics, Beijing Chaoyang Hospital. There were 1 male and 6 females, with a mean age of (57±13) years(43-77 years). The operation time, intraoperative blood lose, blood transfusion and complications were recorded, and the pain relief effects were evaluated by visual analog scale (VAS) score and Oswestry dability index (ODI). The indexes before and after the operation were compared with t test. Results: The average of follow-up time was 13.3 months (6-21 months), and the clinical symptoms relieved significantly. The VAS scores of low back pain and leg pain at 3-day postoperatively and at the last follow-up were (2.28±0.48), (1.57±0.53) and (0.42±0.53), (0.14±0.37), respectively; and the VAS scores were significantly improved when compared with those before the operation[(7.42±0.78), (6.14±1.77)](t=19.718, 6.672, 18.520, 7.937, all P<0.05). At the last follow-up, the ODI score was also significantly lower than that before surgery (54%±10% and 15%±9%, t=12.551, P<0.05). During the follow-up period, one patient had transient hyperreflexia after surgery, and the other 6 patients had no significant complications. None nerve root injury or lower extremity paralysis occurred. Conclusion: PE-TLIF can obtain satisfactory short-term results in the treatment of single-segment lumbar spinal stenosis, with a lower incidence of complications and rapid recovery after surgery.

[Assessment of biomechanical properties of paraspinal muscles in adolescent idiopathic scoliosis].

Objective: To assess the bio-mechanical properties of paraspinal muscles in adolescent idiopathic scoliosis (AIS). Methods: The MyotonPro® device and shear wave elasticity imaging(SWEI) technique were applied to detect the paraspinal muscle tone (F), stiffness (S), relaxation time (R), Deborah number (C) and elasticity (D) of paravertebral muscles on the concave side and convex side of scoliosis curvature at several points: apex of the curve (a), upper (b) and lower (c) limits of the curve in 23 cases of AIS treated from October to December 2017 in Beijing Chaoyang Hospital.Cobb angle of the main curve was measured on the standing anteroposterior whole spine radiograph.Pearson correlation analysis was applied to detect the relation between the bio-mechanical properties and Cobb angle of the main curve. Results: A total of 23 AIS patients [3 males and 20 females, mean age was (15±4) years] were assessed in this study.The mean Cobb angle was (66±33) degrees.The MyotonPro® data showed that the muscle tone on the concave side were all significantly greater than those on the convex side [a: (18.9±2.2) Hz vs (17.4±1.6) Hz, t=4.435, P<0.05; b: (18.2±2.0) Hz vs (16.7±1.7) Hz, t=4.183, P<0.05; c: (18.0±2.3) Hz vs (16.8±1.7) Hz, t=4.520, P<0.05]. The muscle stiffness on the concave side were all significantly greater than those on the convex side at the three points (t=1.974, 2.048, 1.749, all P<0.05). The relaxation time were all longer on the convex side (t=-3.422, -2.713, -2.380, all P<0.05). The Deborah number were greater on the convex side at a and b points (t=-2.939, -2.466, both P<0.05). No significant difference in elasticity was found between the muscles of the two sides.The SWEI results also indicated that the elasticity of the paraspinal muscles of the two sides were similar.The Pearson correlation analysis showed that stiffness on the concave side was moderate positively correlated with Cobb angle of the main curve (r=0.582, P<0.05). Deborah number on the two sides and relaxation time on the concave were moderate negatively correlated with Cobb angle of the main curve (r=-0.632, -0.432, -0.611, all P<0.05). Conclusions: The bio-mechanical properties of paraspinal muscles in AIS are different significantly between the concave and convex side and affected by the severity of scoliosis.

[Biomechanical effects on adjacent segments of different growing-rod fixation in early onset scoliosis].

Objective: To analyse the biomechanical effects on adjacent segments of different growing-rod (GR) fixation in early onset scoliosis through a finite element analysis method. Methods: A severe early-onset scoliosis patient was selected and the pre-operation and post-GR-operation (Upper instrumented levels: T(4), T(5). Lower instrumented levels: L(3), L(4)) whole spine 3-dimentional CT scan data were collected to build the finite models. Based on the different models, biomechanical differences on adjacent segments were analysed. Results: The stress on the adjacent structures decreased after the GR surgery compared with the pre-operation. Compared with the single GR, stress on T(3) vertebrae decreased by 6.2%, stress on T(3/4) disc decreased by 6.7%, stress on T(3/4) ligament decreased by 27.7%, stress on T(6) vertebrae decreased by 16.9%, stress on T(5/6) disc decreased by 1.2%, stress on T(5/6) ligament decreased by 40.4%, stress on L(2) vertebrae decreased by 32.6%, stress on L(2/3) disc decreased by 30%, stress on L(2/3) ligament decreased by 15.6%, stress on L(5) vertebrae decreased by 1.2%, stress on L(4/5) disc decreased by 15.7%, stress on L(4/5) ligament decreased by 100.0% in dual GR structure. The application of hook (s) on the upper instrumented vertebrae (s) decreased the stress on the cranial adjacent segment. Stress on T(3) vertebrae decreased by 2.8% and 2.2%, stress on T(3/4) disc decreased by 2.4% and 1.5%, stress on T(3/4) ligament decreased by 3.6% and 5.7% in single GR and dual GR models separately when the hook (s) were utilized. In the meanwhile, the stress on the adjacent segment was more concentrated in the single GR model. Conclusion: Dual-rod growing-rod and the application of hook (s) on the upper instrumented vertebrae could reduce the stress on the adjacent segments more effectively in patients with early onset scoliosis.