[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(β 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 β 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.

Isomerization of Benzothiadiazole Yields a Promising Polymer Donor and Organic Solar Cells with Efficiency of 19.0

The exploration of high-performance and low-cost wide-bandgap polymer donors remains critical to achieve high-efficiency nonfullerene organic solar cells (OSCs) beyond current thresholds. Herein, the 1,2,3-benzothiadiazole (iBT), which is an isomer of 2,1,3-benzothiadiazole (BT), is used to design wide-bandgap polymer donor PiBT. The PiBT-based solar cells reach efficiency of 19.0%, which is one of the highest efficiencies in binary OSCs. Systemic studies show that isomerization of BT to iBT can finely regulate the polymers' photoelectric properties including i) increasing the extinction coefficient and photon harvest, ii) downshifting the highest occupied molecular orbital energy levels, iii) improving the coplanarity of polymer backbones, iv) offering good thermodynamic miscibility with acceptors. Consequently, the PiBT:Y6 bulk heterojunction (BHJ) device simultaneously reaches advantageous nanoscale morphology, efficient exciton generation and dissociation, fast charge transportation, and suppressed charge recombination, leading to larger VOC of 0.87 V, higher JSC of 28.2 mA cm-2 , greater fill factor of 77.3%, and thus higher efficiency of 19.0%, while the analog-PBT-based OSCs reach efficiency of only 12.9%. Moreover, the key intermediate iBT can be easily afforded from industry chemicals via two-step procedure. Overall, this contribution highlights that iBT is a promising motif for designing high-performance polymer donors.

Step-by-Step Modulation of Crystalline Features and Exciton Kinetics for 19.2% Efficiency Ortho-Xylene Processed Organic Solar Cells

With plenty of popular and effective ternary organic solar cells (OSCs) construction strategies proposed and applied, its power conversion efficiencies (PCEs) have come to a new level of over 19% in single-junction devices. However, previous studies are heavily based in chloroform (CF) leaving behind substantial knowledge deficiencies in understanding the influence of solvent choice when introducing a third component. Herein, we present a case where a newly designed asymmetric small molecular acceptor using fluoro-methoxylated end-group modification strategy, named BTP-BO-3FO with enlarged bandgap, brings different morphological evolution and performance improvement effect on host system PM6:BTP-eC9, processed by CF and ortho-xylene (o-XY). With detailed analyses supported by a series of experiments, the best PCE of 19.24% for green solvent-processed OSCs is found to be a fruit of finely tuned crystalline ordering and general aggregation motif, which furthermore nourishes a favorable charge generation and recombination behavior. Likewise, over 19% PCE can be achieved by replacing spin-coating with blade coating for active layer deposition. This work focuses on understanding the commonly met yet frequently ignored issues when building ternary blends to demonstrate cutting-edge device performance, hence, will be instructive to other ternary OSC works in the future.

[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 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.

[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.

[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(Q_R))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 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.

Drug efficacies on bone mineral density and fracture rate for the treatment of postmenopausal osteoporosis: a network meta-analysis

OBJECTIVE

Globally, a great number of elderly suffer from osteoporosis, especially postmenopausal women. Osteoporosis results in low bone mineral density (BMD) and high risk of fragility fracture. However, there is no defined strategy to select the most suitable anti-osteoporotic drugs for osteoporosis patients. Therefore, this study aims to select the most effective anti-osteoporotic drug for postmenopausal women with osteoporosis.

MATERIALS AND METHODS

Literature search was conducted in PubMed, EMBASE, and the Cochrane Library. Raw data from the related randomized clinical trials were extracted. A pairwise and network meta-analysis model was utilized to assess the efficacy of ten drugs on the percentage change of BMD in the lumbar spine and total hip from baseline to one year of treatment. Risks of vertebral fracture and non-vertebral fracture were evaluated as well. We reported the effect size with a weighted mean difference (WMD) for continuous outcomes and odds ratio (OR) for dichotomous outcomes. All the drugs were ranked based on the surface under the cumulative ranking curve (SUCRA) value. Furthermore, the heterogeneity, consistency and publication bias of enrolled literature were assessed.

RESULTS

With regard to lumbar spine BMD, the ten selected drugs all showed significant efficacy compared with placebo. In regard to total hip BMD and vertebral fracture, with the exception of calcitonin, the remaining nine drugs all showed significant efficacy compared with placebo. Six drugs - abaloparatide, alendronate, risedronate, strontium ranelate, teriparatide, and zoledronate - were significantly more effective compared with placebo for the treatment of non-vertebral fractures. As the SUCRA values indicated, abaloparatide performed the best on improving lumbar spine BMD, vertebral fracture and non-vertebral fracture, while denosumab was the best choice to improve total hip BMD.

CONCLUSIONS

To sum up, abaloparatide, denosumab, and teriparatide showed the best efficacy for the treatment of postmenopausal osteoporosis, especially abaloparatide.

Circ-VANGL1 promotes the progression of osteoporosis by absorbing miRNA-217 to regulate RUNX2 expression

OBJECTIVE

This study aims to investigate whether circ-VANGL1 can promote the progression of osteoporosis (OP) by absorbing miRNA-217 to regulate RUNX2 expression.

PATIENTS AND METHODS

The serum levels of circ-VANGL1, miRNA-217 and RUNX2 in OP patients and non-OP patients were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Their expression levels in human bone marrow mesenchymal stem cells (hBMSCs) at different time points of osteogenesis differentiation were determined as well. The expression levels of RUNX2 and osteogenic proteins (BSP, OCN, OPN) in hBMSCs were detected by Western blot. Dual-Luciferase reporter gene assay was performed to verify the relationship among circ-VANGL1, miRNA-217 and RUNX2. Alkaline phosphatase (ALP) staining was conducted to evaluate the degree of osteogenic differentiation influenced by circ-VANGL1 and miRNA-217.

RESULTS

OP patients presented a higher serum level of miRNA-217 and lower serum levels of circ-VANGL1 and RUNX2 relative to non-OP patients. Circ-VANGL1 accelerated osteogenic differentiation by absorbing miRNA-217 to regulate RUNX2 expression. Moreover, miRNA-217 inhibited osteogenic differentiation by degrading RUNX2 by targeting to RUNX2 3'UTR. The overexpression of circ-VANGL1 upregulated expressions of RUNX2, BSP, OCN, and OPN. Meanwhile, ALP activity increased in hBMSCs overexpressing circ-VANGL1. However, co-overexpression of circ-VANGL1 and miRNA-217 did not alter RUNX2 expression. ALP activity in hBMSCs co-overexpressing circ-VANGL1 and miRNA-217 slightly increased, but had no difference with controls.

CONCLUSIONS

Circ-VANGL1 promotes the development of OP via binding to miRNA-217 to downregulate RUNX2 expression.

[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.

[Application of meticulous anatomy skills with straight bipolar electric coagulation forceps in thyroid surgery]

Objective: To compare the efficacies of the two techniques of "micro-hemostasis and micro-cutting" with straight bipolar electrocoagulation forceps and traditional clamp-ligation for hemostasia in thyroid surgery. Methods: A total of 228 patients who underwent surgical treatment for thyroid neoplasms in our hospital between January 2015 and December 2018 were retrospectively analyzed, including 50 males and 178 females, aged 23-68 years old. Of those, 150 cases as electric knife group received traditional thyroid surgery between January 2015 and December 2018 and 78 cases as bipolar electrocoagulation group received thyroid surgery by using the technique of bipolar electrocoagulation with meticulous anatomy between January 2018 and December 2018. The total operation time, single operation time, intraoperative hemorrhage, postoperative drainage volume on the first day, postoperative hoarseness and hypocalcemia were compared between the two groups. SPSS 16.0 was used to analyze the data. Results: The total operation time and intraoperative hemorrhage in the bipolar electrocoagulation group were significantly lower than those in the electric knife group ((59.33±18.29)min vs (77.21±25.39)min, (14.83±9.22)ml vs (36.86±11.80)ml, all P<0.01). The single operation time of the bipolar electrocoagulation group was shorter than that of the electric knife group((10.25±6.16) min vs (20.34±7.24)min, (16.25±7.15)min vs (35.68±8.25)min, (12.12±5.25)min vs (20.68±7.26)min, t value was 3.948,16.262,8.238, all P<0.01).There was no significant difference between the two groups in postoperative drainage volume on the first day (P>0.05) and the incidence of postoperative hoarseness (P>0.05), while the incidence of hypocalcemia in the bipolar electrocoagulation group(10.26%) was lower than that in the electric knife group(21.33%,χ(2)=4.353, P<0.05). Conclusions: The fine dissection for thyroid operation can be achieved by using straight bipolar electrocoagulation tweezers. The use of "micro-hemostasis" and "micro-cutting" technique with bipolar electrocoagulation tweezers can greatly reduce intraoperative bleeding, operation time and postoperative complication.

[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.

[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.

[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.

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 (β = 0.071, P = 0.0006) than in controls (β = 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.

[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.

[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.

[Effects of different pelvic incidence minus lumbar lordosis mismatch after long posterior instrumentation and fusion for adult degenerative scoliosis]

Objective: To evaluate the influence of PI-LL (pelvic incidence minus lumbar lordosis mismatch) on scoliosis correction, living quality and internal fixation related complications for adult degenerative scoliosis (ASD) after long posterior instrumentation and fusion. Methods: A total of 79 patients with ADS underwent long posterior instrumentation and fusion in the Department of Orthopedics at Beijing Chao Yang Hospital from January 2010 to January 2014 were retrospectively reviewed.There were 21 males and 58 females aging from 55 to 72 years with the mean age (63.4±4.8)years. The patients were divided into three groups according to immediately postoperative PI-LL: PI-LL<10°, 10°≤PI-LL≤20°, PI-LL>20°.Compare the Cobb's angles, PI-LL, Japanese Orthopaedic Association (JOA) score, Oswestry Disability Index (ODI), Visual Analog Scale (VAS) and Lumbar Stiffness Disability Index (LSDI). Measurement data were compared via t test and ANOVA, enumeration data were compared via Kruskal-Wallis test, noncontiguous data was performed by χ(2) test. Univariate linear regression equation was performed to investigate the relative influences of postoperative PI-LL on postoperative radiographic parameters and clinical outcome. Results: All the operations were successful without intraoperative complications. The operation time was 145-310 minutes (235.3±42.0) minutes, the intraoperative blood loss was 300-5 300 ml (1 021±787) ml, the duration of hospital was 12-18 d (14.5±1.3) d. A total of 4 to 10 (7.0±1.1) vertebra levels were fused. Compared to preoperative, the Cobb's angle of scoliosis ((4.2±1.8)° vs. (20.1±2.7)°), PI-LL ((16.1±8.6)° vs. (36.0±4.3)°), JOA (3.0±1.3 vs. 5.5±1.2), ODI (24.4±8.1 vs. 62.9±2.7), VAS (3.0±1.0 vs. 6.8±1.3) were significantly decreased postoperative (t=18.539~53.826, P<0.01). Compared to preoperative, postoperative Cobb's angle of scoliosis ((4.1±2.7)° vs. (19.5±2.7)°, (4.0±1.4)° vs. (20.2±2.4)°, (4.7±0.9)° vs. (20.6±3.0)°) (t=21.148-45.355, P<0.01) and PI-LL ((5.2±2.8)° vs. (35.8±4.9)°, (17.9±2.9)° vs. (37.2±3.9)°, (25.8±2.7)° vs. (34.5±4.0)°) (t=7.227-38.250, P<0.01) were significantly reduced postoperative in PI-LL<10° group, 10°≤PI-LL≤20° group and PI-LL>20° group. Compared to preoperative, ODI (27.7±4.9 vs. 63.3±2.6, 17.7±5.9 vs. 63.1±2.8, 30.6±6.5 vs. 62.3±2.5) (t=21.218~50.858, P<0.01), JOA (2.8±1.2 vs. 5.2±1.2, 3.3±1.1 vs. 5.7±1.1, 2.8±1.7 vs. 5.7±1.2) (t=9.042-16.025, P<0.01) and VAS (2.9±1.2 vs.7.0±1.3, 3.3±0.9 vs.7.0±1.4, 2.9±0.8 vs. 6.3±1.2) (t=16.073-22.214, P<0.01) were all significantly reduced at last follow-up. There were statistic differences in ODI and LSDI (F=38.477, P<0.01; F=37.063, P<0.01) at the last follow-up among the three groups. There was a negative correlation in PI-LL and LSDI according to linear regression (B=-5.838, P<0.01) in the last follow-up. All the patients were followed up, the follow-up duration were 2 to 5 years with the mean (3.1±0.7) years. The internal fixation failure related complications in 3 years included proximal junctional kyphosis (PJK) in 19 cases, internal fixation loosening in 6 cases. Eight patients received reoperation for severe local pain and low extremity symptoms. PJK occurrences were significantly different among PI-LL<10° group, 10°≤PI-LL≤20° group and PI-LL>20° group. Conclusions: The PI-LL between 10° and 20° may be the best choice in ADS patients after long posterior instrumentation and fusion for its better clinical outcome and less proximal junctional kyphosis (PJK). The overcorrection of LL may lead to more serious postoperative lumbar stiffness.

[Topping-off surgery versus double-segment fusion for treatment of lumbar degenerative disease with mid-long term follow-up]

Objective: To compare the mid-long term clinical effect of Topping-off surgery and lumbar fusion surgery for two-segmental lumbar degenerative disease. Methods: From March 2009 to March 2012, one hundred and twenty-six consecutive patients (Topping-off surgery and two-segment PLIF surgery) were studied in Orthopedics Department, Beijing Chao-Yang Hospital, Capital Medical University.The VAS and ODI were used to assess clinical symptoms.All patients underwent flexion/extension radiographs examinations before surgery, 1, 2 years and last follow-up postoperatively.Lumbar lordosis, sacral slop, data of Coflex segment and adjacent segment (disc height index, range of motion, foraminal height, foraminal width and Pfirrmann classification of intervertebral disc in MRI) were recorded.The paired double-tailed t test was used to analyze the differences in the results from baseline to each postoperative time point.The paired double-tailed t test was used in both groups to analyze the differences in the results from baseline to each postoperative time point.The Chi-square test was used to evaluate the differences between the incidences of adjacent segment degeneration(ASD) in the groups. Logistic regression analysis was used to analyze risk factors for developing radiographic ASD. Results: In topping-off group, 60 patients, average operation time was (134.5±10.2) min. The average blood loss was (301.5±64.6) ml.In fusion group, 68 patients, average age (58.3±4.6) years.The average follow-up time was (47.5±5.1) months.The average operation time was (158.6±19.3) min (P=0.000). The average blood loss was (413.6±131.3) ml (P=0.000). Sex, age, body mass index and intervertebral disc grading were matched between the two groups.Better improvement in VAS back pain score was noted in the topping-off group over the fusion group (P=0.030). Both groups achieved good recovery in ODI and improvement in VAS leg pain and back pain scores at last follow-up postoperatively.In the Topping-off group, FH increased from 10.5 mm at baseline to 11.8 mm at 1 year after surgery (P=0.000) and then decreased mildly in the third postoperative year, while in the fusion group, showed no significant change at all postoperative time points.In the fusion group, the disc height and FW at the same segment were no significant change after first year follow-up, while ROM was significantly decreased after surgery (P=0.000). Foraminal height, foraminal width and intervertebral disc height of adjacent segment of Coflex implant level were found decreased at the end of the postoperative follow-up, while compared with preoperative data no significant difference (P>0.05). At last follow-up, eight patients (13.3%) in the Topping-off group and eighteen patients (26.5%) in the fusion group developed ASD (P=0.033). Conclusions: Topping-off surgery compared with two-segment lumbar fusion surgery can achieve a good result in cases with pre-existing mild or moderate adjacent segment degeneration, restrict the adjacent segment's range of motion and reduce the adjacent segment degeneration. Under strict indications, Topping-off surgery is an acceptable alternative to fusion surgery for the treatment of two-segment lumbar disease.

[Efficacy of Coflex in the treatment of lumbar spondylolisthesis]

Objective: To study the clinical results of Coflex and lumbar posterior decompression and fusion in the treatment of lumbar degenerative spondylolisthesis at L(4-5). Methods: Thirty-eight patients with Grade Ⅰ degenerative spondylolisthesis, from January 2008 to December 2011 in Beijing Chaoyang Hospital, Capital Medical University were reviewed, and patients were divided into two groups by randomness. Group A was treated with Coflex and group B with pedicle instrumentation and interbody fusion. Fifteen patients were included in group A, and 23 patients were included in group B. In group A, the average age was (56.3±9.1) years. In group B, the average age was (58.2±11.2) years. The clinical results were evaluated by visual analogue scale (VAS) and Oswestry disability index (ODI). Slip distance (SD) was measured before and after surgery, and the changes of intervertebral angle at index level and adjacent level were also recorded. Results: The follow-up period was 36 to 68 months, with the average of (39±14) months in the both groups. The operation time and bleeding volume of patients in group A were significantly less than that of group B (P<0.05). In both groups, the difference of ODI and VAS before operation and postoperative follow-up were statistically significant (P<0.05). There was no significant difference between lumbar intervertebral angle and the sliding distance in group A at all time points. In the group B, there was a significant increase in the intervertebral angle and the sliding distance at L(3-4) and L(5)-S(1 )level after surgery, the difference at upper and below adjacent segment before and after surgery were statistically significant. Conclusions: Coflex interspinous dynamic stabilization system has same excellent clinical results as pedicle screw instrumentation and fusion surgery for the treatment of L(4-5) degenerative spondylolisthesis; no significant progression of spondylolisthesis been observed during more than 3 years follow-up, and no obvious adjacent segment degeneration has been found.

[Clinical outcome of mid-term follow-up of anterior cervical non-fusion surgery versus anterior cervical discectomy and fusion for cervical spondylosis]

OBJECTIVE

To evaluate the clinical and radiological outcomes of artificial cervical disc replacement (Prodisc-C), dynamic cervical implant and anterior cervical discectomy and fusion (ACDF) in the treatment of cervical spondylosis.

METHOD

From May 2011 to May 2013, a total of 44 cervical spondylosis patients that received cervical disc arthroplasty (Prodisc-C), dynamic cervical implant (DCI) or ACDF were retrospectively reviewed in Orthopedics Department, Beijing Chaoyang Hospital, Capital Medical University.The patients were divided into three groups by surgical methods.Parameters as gender, age, the operation time, blood loss and average hospital stay of three groups were compared.The patients were followed 3 months, 6 months, 12 months and 24 months postoperatively.Neck disability index (NDI), Japanese Orthopaedic Association (JOA) Score and Visual Analogue Scale (VAS) were used to evaluate the clinical outcomes of the three groups.We also measured the cervical lordosis, range of motion of surgical segment and adjacent segment and height of disc at pre-op and post-op.

RESULT

All the patients were got at least 24 months follow-up.The differences between postoperative JOA, NDI and VAS scores and preoperative scores were of statistical significance (P<0.05). There was no statistical difference in average hospital stay, JOA, NDI and VAS recovery rate (P>0.05) among three groups.But the operative time and intraoperative blood loss were statistically different (P<0.05). Compared the pre-and postoperative ROM of C2-7, operative, upper and lower levels of each group respectively, the difference between pre-and postoperative ROM of ACDF group were of statistically significant [(16.6±3.6)°, (22.3±4.6)°, (18.1±3.1)°, P<0.05], while was no statistically significant of non-fusion group(P>0.05). There was no statistically significant difference between pre-and postoperative ROM of upper and lower levels among three groups (P>0.05), but had statistically difference in operative levels [(7.0±1.0) mm, (9.2±1.5) mm, (6.8±1.4) mm, P<0.05]. And there are no serious postoperative complications.

CONCLUSION

Two cervical non-fusion surgery and ACDF have received good clinical effects in the treatment of spondylotic myelopathy or radicular spondylosis.The artificial cervical disc replacement and dynamic cervical implant can not only recover cervical lordosis and keep the range of motion and stability of the surgical segment, but also reduce the incidence of compensatory motion at adjacent segments and will prevent from adjacent segment degeneration.

[Radiographic study of Coflex interspinous device for lumbar spinal stenosis]

OBJECTIVE

To assess the radiography change of lumbar spinal stenosis (LSS) treated with the implantation of Coflex interspinous device retrospectively.

METHODS

Sixty patients (34 male and 26 female) with LSS who underwent the decompression and Coflex device implanted surgery from January 2010 to December 2013 were followed up. The mean age of the patients was 59.4 years. There were 33 cases underwent Coflex surgery and 27 cases underwent Topping-off surgery. The Coflex segment ranged from L1/2 to L4/5 (L1-2: 1, L2-3: 5, L3-4: 19, L4-5: 35). The foraminal height, foraminal width and intervertebral space height change of the Coflex segment as well as its adjacent segment were recorded pre-/post-operatively and at last follow-up.Meanwhile, the Oswestry Disability Index(ODI) and Visual Analog Scale(VAS) were measured in all patient pre-/post-operatively and at last follow-up. The measurement data was recorded asx±s. And the independent and paired samples t-test was used to conduct the statistical analysis.

RESULTS

The foraminal height(FH) increased from (19.82±2.38) mm to (22.28±2.95) mm (P<0.05) post-operatively, and the FH decreased to (19.31±3.32) mm at the last follow up(P>0.05, compared to the post-operation). The average foraminal width(FW) was 11.2 mm, 11.58 mm and 11.12 mm at pre-/post-operation and follow up, which had no significant different change(P>0.05). The post-operative intervertebral space height (ISH) increased from (7.84±1.56) mm to (10.05±2.39) mm(P<0.05), and the ISH decreased to (7.91±1.77) mm at the last follow up(P>0.05, compared to the post-operation). The amount of the decreased FH and ISH had no significant difference when comparing the Coflex segment with its adjacent (Coflex±1) segments (P>0.05). The lumbar lordosis(LL) was 43.13°±15.93°, 38.41°±10.82° and 43.10°±13.21° at pre-/post-operation and follow up, there was no significant difference between pre- and post-operation(P>0.05). All patients showed statistically significant improvement(P<0.05) in the clinical outcome assessed in the VAS and ODI at the time of follow up compared to the pre-operation. The ODI score decreased from 65.12±13.56 to 9.89±1.77; the VAS score decreased from 8.02±1.81 to 1.66±0.51.

CONCLUSIONS

Coflex device could temporarily improve the FH and ISH after operation. However, it could not maintain the improvement as the follow-up time extended. The surgical decompression is the responsible factor for the good clinical outcome but not the improvement of FH.

[Risk factors of postoperative major complication after spine deformity surgery]

OBJECTIVE

To analyze risk factors of major complications after spinal deformity surgery.

METHODS

From January 2011 to December 2014, 254 consecutive patients undergone spinal deformity surgery , 68 male and 186 female, average age 22.1(3-73) years, were divided into two groups based on if they had major complications after surgery.Univariate and multivariate analysis (Logistic regression) were used to identify the risk factors.

RESULTS

Among them, 29 patients had major complications after surgery.Univariate risk factors showed that medical history, scoliosis operation history, preoperative nerve injury, vertebral number of major curve, cobb of major curve, Kyphosis(>90°), time of operation, operative bleeding and osteotomy of group Ⅰ were higher or longer than those of group Ⅱ.Maximal voluntary ventilation (MVC) and orthopaedic rate of group Ⅰ were worse than those of group Ⅱ[(63.5%±23.9%)vs(76.7%±21.9%), (53%±23%) vs(68%±21%), P<0.05]. Logistic regression identified that preoperative nerve injury(OR=5.976), medical history>10 years (OR=4.095), MVC observed/predicted<50(OR=7.405), time of operation>5 h (OR=3.510), osteotomy(OR=3.472)were final risk factors for major complications.

CONCLUSIONS

Major complications after surgery to treat spinal deformity can be predicted through preoperative nerve injury, medical history, maximal voluntary ventilation observed/predicted, time of operation and osteotomy during the surgery.The patients with these risk factors need more preoperative care and postoperative care to reduce the occurrence of major complications.

Quantitative changes in spinal canal dimensions using interbody distraction for spondylolisthesis

STUDY DESIGN

An experimental study was performed using cadaveric lumbar spines to evaluate the effect of anteriorly or laterally placed interbody distraction implants on the alteration of spinal canal and neuroforaminal dimensions.

OBJECTIVES

To quantify changes in the spinal canal and neuroforaminal dimensions using interbody fusion devices inserted at various configurations in cadaveric lumbar spines exhibiting degenerative spondylolisthesis.

SUMMARY OF BACKGROUND DATA

Although several clinical studies have demonstrated successful treatment of degenerative spondylolisthesis with anterior interbody fusion, no study has shown the role of interbody distraction in improving lumbar spinal canal and foraminal stenosis.

METHODS

Five fresh cadaver lumbar spines exhibiting a degenerative spondylolisthesis or retrospondylolisthesis were used for the study. Computed tomography scans of each specimen and a silicon mold of the left intervertebral foramens were repeated in a consistent manner after pure compressive load (150 lb) was applied to simulate physiologic load (intact case), after two BAK (Sulzer SpineTech Inc., Minneapolis, MN) distraction plugs were anteriorly inserted into the intervertebral disc space (anterior distraction cases), and after one long BAK cage was laterally inserted from the left side (lateral distraction case). The cross-sectional area of the spinal canal was measured from computed tomography images using National Institutes of Health image software (Bethesda, MD). The spinal canal volume was calculated using the cross-sectional area and total scan thickness. Left intervertebral foraminal volumes were calculated from the weight of the silicon mold injected into the foramen. Descriptive statistics and a Student's t test were used to detect statistical differences in the spinal canal and neuroforaminal volumes before and after interbody distraction.

RESULTS

The cross-sectional canal area was significantly increased after anterior distraction (35.11%) and lateral distraction (33.14%). The spinal canal volume was markedly increased with anterior distraction (19.92%) and lateral distraction (21.96%). Left foraminal volume was also enhanced by 40.25% for anterior distraction and 41.03% for lateral distraction.

CONCLUSIONS

Interbody distraction either by anteriorly inserted plugs or laterally inserted threaded cagescan immediately improve the narrowed canal area and increase spinal canal, as well as foraminal volume for lumbar degenerative spondylolisthesis or retro- spondylolisthesis.

[Surgical treatment of single level unstable degeneration with foraminal stenosis]

OBJECTIVES

Lumbar spine single level unstable degeneration with foraminal stenosis was treated with unilateral decompression, disc excision, posterolateral interbody fusion utilizing single BAK cage and count-lateral facet joint screw fixation. The short-term and mid-term clinical results were evaluated.

METHODS

There were thirty patients (13 male, 17 female) with an average age of 46.5 years. From posterior approach, all patients underwent unilateral decompression, disc excision, interbody fusion with posterolateral inserted single BAK cage, and count-lateral facet joint screw fixation.

RESULTS

All patients underwent surgery safely without severe complications occurred such as infection and neurological damages. The average follow-up time was 12 months (6 - 18 months) with complete relief of symptoms. Solid fusion was achieved in all but 2 patients at final follow-up. 90% of the patients obtained successful clinical outcome.

CONCLUSIONS

Complete decompression of the neural foramen can relief the symptoms, and interbody fusion utilizing threaded cage can restore the height of disc space and withstand axial loading of the spine. Addition of the facet joint fixation increased the postoperative segment stability and enhances solid fusion. With less invasive and preservation of part of the posterior elements of the lumbar spine and the solid fusion achieved, we consider it a sound procedure for the treatment of single level unstable degeneration with foraminal stenosis of lumbar spine. Long-term follow-up results needs to be observed.

Posterior lumbar interbody fusion using posterolateral placement of a single cylindrical threaded cage

STUDY DESIGN

An in vitro biomechanical study of posterior lumbar interbody fusion (PLIF) with threaded cages was performed on 18 bovine lumbar functional spinal units.

OBJECTIVES

To compare the segmental stiffness among PLIF with a single long posterolateral cage, PLIF with a single long posterolateral cage and simultaneous facet joint fixation, and PLIF with two posterior cages.

SUMMARY OF BACKGROUND DATA

In most cases, PLIF with threaded cage techniques needs bilateral facetectomy, extensive exposure, and retraction of the cauda equina. Posterior element deficiency is detrimental to postoperative segmental stiffness.

METHODS

All specimens were tested intact and with cage insertion. Group 1 (n = 12) had a long threaded cage (15 x 36 mm) inserted posterolaterally and oriented counter anterolaterally on the left side by posterior approach with left unilateral facetectomy. Group 2 (n = 6) had two regular-length cages (15 x 24 mm) inserted posteriorly with bilateral facetectomy. Six specimens from Group 1 were then retested after unilateral facet joint screw fixation in neutral (Group 3). Similarly, the other six specimens from Group 1 were retested after fixation with a facet joint screw in an extended position (Group 4). Nondestructive tests were performed in pure compression, flexion, extension, lateral bending, and torsion.

RESULTS

The PLIF procedure involving a single cage (Group 1) had a significantly higher stiffness than PLIF with two cages (Group 2) in left and right torsion (P < 0.05). Group 1 had higher stiffness values than Group 2 in pure compression, flexion, and left and right bending, but differences were not significant. Group 3 had a significant increase in stiffness in comparison with Group 1 for pure compression, extension, left bending, and right torsion (P < 0.05). For Group 4, the stiffness significantly increased in comparison with Group 1 for extension, flexion, and right torsion (P < 0.05). Although there was no significant difference between Groups 3 and 4, Group 4 had increased stiffness in extension, flexion, right bending, and torsion.

CONCLUSIONS

Posterior lumbar interbody fusion with a single posterolateral long threaded cage with unilateral facetectomy enabled sufficient decompression while maintaining most of the posterior elements. In combination with a facet joint screw, adequate postoperative stability was achieved.

[Significance of surgical treatment of bursting fracture with CT estimation analysis of the anatomy of pedicle of vertebral arch]

Using CT analysis of 3-D anatomical data of the pedicle of the vertebral arch as a guideline, we standardized the pedicle screw insertion technique. Fourty-six bursting fracture cases were treated using a AF 3-D pedicle screw system with the standard technique and followed up for over 12 months. Comparision was made with the former non-standard technique performed in 72 cases. The results showed that each screw reached the maximum depth with an accurate angle. Comparision of the former non-standard technique showed a significant difference between the two groups. 46 bursting fracture cases obtained anatomical reduction in 3-D and rigid fixation after follow-up for 12 months. Pedicle screw, inserted through the pedicle anatomical axis can reach the maximum depth, that will achieve best stability and ideal clinical result. CT analysis supplies reliable individual data for standardization of pedicle screw insertion.

Global mapping of structural solutions provided by the extended X-ray absorption fine structure ab initio code FEFF 6.01: structure of the cryogenic photoproduct of the myoglobin-carbon monoxide complex

X-ray methods based on synchrotron technology have the promise of providing time-resolved structural data based on the high flux and brightness of the X-ray beams. One of the most closely examined problems in this area of time-resolved structure determination has been the examination of intermediates in ligand binding to myoglobin. Recent crystallographic experiments using synchrotron radiation have identified the protein tertiary and heme structural changes that occur upon photolysis of the myoglobin--carbon monoxide complex at cryogenic temperatures [Schlichting, I., Berendzen, J., Phillips, G., & Sweet, R. (1994) Nature 371, 808--812]. However, the precision of protein crystallographic data (approximately 0.2 A) is insufficient to provide precise metrical details of the iron--ligand bond lengths. Since bond length changes on this scale can trigger reactivity changes of several orders of magnitude, such detail is critical to a full understanding of metalloprotein structure--function relationships. Extended X-ray absorption fine structure (EXAFS) spectroscopy has the potential for analyzing bond distances to a precision of 0.02 A but is hampered by its relative insensitivity to the geometry of the backscattering atoms. Thus, it is often unable to provide a unique solution to the structure without ancillary structural information. We have developed a suite of computer programs that incorporate this ancillary structural information and compute the expected experimental spectra for a wide ranging series of Cartesian coordinate sets (global mapping). The programs systematically increment the distance of the metal to various coordinating ligands (along with their associated higher shells). Then, utilizing the ab initio EXAFS code FEFF 6.01, simulated spectra are generated and compared to the actual experimental spectra, and the differences are computed. Finally, the results for hundreds of simulations can be displayed (and compared) in a single plot. The power of this approach is demonstrated in the examination of high signal to noise EXAFS data from a photolyzed solution sample of the myoglobin--carbon monoxide complex at 10 K. Evaluation of these data using our global mapping procedures placed the iron to pyrrole nitrogen average distances close to the value for deoxymyoglobin (2.05 +/- 0.01 A), while the distance from iron to the proximal histidine nitrogen is seen to be 2.20 +/- 0.04 A. It is also shown that one cannot uniquely position the CO ligand on the basis of the EXAFS data alone, as a number of reasonable minima (from the perspective of the EXAFS) are observed. This provides a reasonable explanation for the multiplicity of solutions that have been previously reported. The results presented here are seen to be in complete agreement with the crystallographic results of Schlichting et al. (1994) within the respective errors of the two techniques; however, the extended X-ray absorption fine structure data allow the iron--ligand bond lengths to be precisely defined. An examination of the available spectroscopic data, including EXAFS, shows that the crystallographic results of Schlichting et al. (1994) are highly relevant to the physiological solution state and must be taken into account in any attempt to understand the incomplete relaxation process of the heme iron for the Mb*CO photoproduct at low temperature.

[Biomechanics of AF new 3-d pedical screw system and treatment of 31 patients with unstable thoracolumbar fracture]

For anatomic reduction of the spinal frectures, the 3 dimensional multiple correction forces were needed. Several pedical screw systems were designed for reducion and fixation of the spinal fractures as the AO universal joint system and the RF angle screw system. Because of the contradiction of the universal joint and the fixed angle, a new generation of RF was designed and named AF (atlas fixator) system. This is a new concept of 3-D reduction, without complex structure as universal joint, but has truly 3-D adjustment that allowed to reduce the intra-canal compromise. It also provided rigid fixation to maintain the reduction. Comparison with CD, AO, Steffee, and RF, the AF was truly 3-D reduction in XTZ axis. It provided strong symmetric transmitter orthotic force to correct the deformity. 31 patients with unstable thoracolumbar fractures were treated with the new AF system. 17 had partial (15) or complete (2) neurologic deficits. The AF system provided accurate angle to restore the normal thoracic-lumbar lordosis and to maintain it. All patients had a anatomic reduction by AF system. The spinal canal area increased over 33% by CT scan (P < 0.01). All cases were followed up over 8 months. No one deteriorated neurologically after AF fixation.

[Adult spondylolisthesis treated with the combination of angled and pushing-pulling pedicle screws]

Altogether 28 patients with degenerative (22 cases), isthmic (4 cases), and post-traumatic (2 cases) spondylolisthesis were treated with a reduction fixation system using both angled and pushing-pulling pedicle screws. Preoperatively, the percentages of the sliprage were < or = 25% in 15 cases, < or = 50% in 11, and < or = 75% in 2 cases. All patients had low-back pain and/or leg pain. Postoperatively, 28 cases obtained a nearly anatomical reduction. The average rate of correction was 98%. There is a significant difference (P < 0.01) compared with preoperation. After reduction, all patients had only two segmental rigid fixations with posterolateral bone grafting or postero-inter-body fusion. 27 cases had satisfactory pain relief postoperatively. No patient deteriorated neurologically with surgery. All patients were followed up for a minimum of 8 months ranging from 8 to 28 months (average 19). At the end of follow-up, in 26 patients correction remained unchanged with X-ray demonstrating radiographic evidence of fusion. Neither pseudarthroses nor significant complications occurred. The new system is a safe and effective pedicular fixation system, it has a three-dimensional correction force that allows for reduction of the spondilolisthesis and fixation of only two segments. It also gives more rigid fixation to maintain the reduction and increase the fusion rate. The new system gives satisfactory results over conventional hook and sub-lamina wire and other segmental spinal pedicle screw instrumentation systems.

Enhancement of resistance to infectious diseases by oral administration of brewer's yeast

The effect of oral administration of brewer's yeast on resistance to infectious diseases was studied in laboratory animals. It was shown that there was a significantly increased enhancement of resistance to seasonal respiratory and enteric infections in rhesus monkeys. Similarly, enhanced resistance to experimental chronic infections was observed in mice after yeast administration. A 2-week lag occurred between the initiation of yeast treatment and the expression of enhanced resistance. Study of the mechanism of the yeast-induced enhancement of resistance to infection leads to the conclusion that it is based on in vivo stimulation of phagocytosis, as measured by the "phagocytic index." No effect of brewer's yeast on circulating antibody levels was detected.