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Laminectomy with instrumented fusion (LF) has demonstrated better prevention of ossification of posterior longitudinal ligament (OPLL) growth compared to laminoplasty (LP). There remains uncertainty, however, as to which surgical approach is more beneficial with respect to clinical outcomes and complications. We retrospectively reviewed 273 cervical OPLL patients of more than 3 levels, from the two institutions’ databases, who underwent LF or LP between January 1998 and January 2016. Each 273 patient (85 with LF, 188 with LP) was assessed for postoperative neurologic and radiologic outcomes, complications and reoperations. The mean length of follow-up was 40.11 months. There were baseline differences between cohorts. Overall, postoperative JOA recovery rate at last follow up was significantly better in the LP group with similar improvement in visual analog neck score. Postoperative C2-7 Cobb angle was decreased compared to baseline for both LF and LP cohorts, but there was no significant difference between groups. Complications occurred in 19 (22.35%) LF patients, and 11 (5.85%) LP patients, with higher incidence of C5 palsy and instrumentation failure in the LF group. Four LF patients (4.71%) and five LP patients (2.66%) underwent reoperation during the follow up period.

Background Destruction of the spine is a huge complication of infectious spondylitis and surgical intervention is required. However, vertebral defect is a major problem after surgical intervention and numerous methods have been researched to solve this problem. There are known methods that use variously designed, patient-customized 3-dimensional (3D)-printed implants in various medical fields. The use of 3D-printed implants has also been attempted in treating defects in the spine. We present a case of failure of expandable titanium cage fusion after infection, treated using a 3D-printed implant. Case Description The patient had undergone reconstruction surgery with expandable titanium cage due to infectious spondylitis and needed reoperation owing to recurrence of infections and failure of bone fusion. The problem we faced in this operation was a large vertebral defect, for which we used a 3D-printed implant. After 3 years of follow-up, the implant and bone fusion were intact and infection or mechanical complications were not seen. Conclusions A 3D-printed implant could be an acceptable and alternative treatment option for replacing a large vertebral defect.

PBI membranes are recently discussed as stable, well performing membranes for vanadium redox flow batteries (VRFB). Blending meta-PBI with an anion exchange polymer (FAA3i) slightly reduces the coulomb efficiency from 99.7 to 97.8%, but strongly increases the voltage efficiency from 82.5 to 88.2%, leading to an increased energy efficiency (86.2% at 80 mA cm−2), exceeding that of meta-PBI (82.2%) and N212 (83%). Apparently, since the conductivity of sulfuric acid has a maximum around a concentration of 3.8 M, the concentration of the absorbed acid has a dominant influence on the conductivity. Addition of FAA3i decreases the concentration of the acid absorbed by PBI membranes. Furthermore, an ex-situ stability test in 1.5 M V5+ solutions in 2 M sulfuric acid for 87 days showed a very high stability for meta-PBI and Nafion 212, while the commercial FAA3 membrane disintegrated into pieces. Blending of meta-PBI and FAA3 decreased the stability, as proven by formation of V4+, but all tested blend membranes retained their membrane shape and could still be handled. Blending with FAA3 reduces the tensile strength and Young's modulus of meta-PBI, and doping with sulfuric acid leads to a further decrease in the mechanical strength. However, an acid doped PF-21 still showed a tensile strength of 37 MPa and a Young's modulus of 0.7 GPa.

Because of the scarcity of atypical spinal meningioma, there is a lack of research on this type of tumor or its associated metastases.The aim of this study was to investigate the biological behavior of atypical spinal meningioma and identify its prognostic factors by reviewing surgical and clinical outcomes of patients with these tumors.A retrospective chart review was performed.We retrospectively reviewed the data from all patients who underwent spinal cord tumor excision between 1994 and 2017. Seventeen patients were pathologically proven to have atypical spinal meningioma.We examined patients' neurologic status by determining their Nurick scores before and after surgery. Moreover, imaging studies, laboratory data, and the employed surgical method were analyzed retrospectively, as was the Ki-67 index and prognosis following postoperative radiation therapy.The ranges, locations, and pathologic diagnoses of the tumors were extracted from the radiological and pathological records of each patient. The extent of surgery and progression of disease were confirmed using postoperative enhanced magnetic resonance imaging. Patients were divided into two atypical spinal meningioma groups: primary and metastatic. The demographics, age, sex, presenting symptom duration, tumor location, Simpson resection grade, Ki-67, radiotherapy, recurrence, overall survival, and progression-free survival of patients in both groups were compared.Seventeen patients were included in the analysis, of whom 12 (70%), 4 (24%), and 1 (6%) had tumors in the thoracic, cervical, and sacral regions, respectively. Complete and subtotal resections were achieved in 15 (88%) and 2 (12%) patients, respectively. Overall and progression-free survival rates in patients who underwent complete resection were longer than those in patients who underwent subtotal resection (p.001). Four patients (24%) had metastatic meningiomas in the brain, among whom three were administered adjuvant radiotherapy after surgery. Two patients with intramedullary atypical spinal meningioma had metastatic tumors and experienced poorer prognoses. The 5-year overall and progression-free survival rates were 84.4% and 85.2%, respectively. The Simpson resection grade, Ki-67 index, and preoperative neurologic status were found to be important prognostic factors on univariate Cox regression analysis (p.05).Complete resection should be considered as a primary treatment modality for individuals with atypical spinal meningioma. If subtotal resection is performed, adjuvant therapy can be administered.

To evaluate prevalence, incidence, morbidity, and mortality rates of cervical ossification of posterior longitudinal ligament (OPLL) using data from a 12-year national cohort of 1,025,340 Korean people.A nested case-control cohort study was performed from 2002 to 2013 using the insurance claims database provided by the National Health Insurance Service. We examined prevalence and incidence of cervical OPLL. Age- and sex-matched control subjects were randomly extracted, with 10 times the number of OPLL cases. Differences in sex, comorbidity, and relative survival rate compared with control subjects were assessed.Cumulative prevalence was 20,960 per 1,025,340 people for 12 years. Annual incidence was approximately 199-371 per 1 million people. Overall crude mortality rate was 7.64%. Relative survival rate of OPLL cases was not significantly different from control cases. Diabetes, hypertension, cardiovascular disease, and cerebrovascular disease, except renal disease, correlated significantly with OPLL compared with control cases (P0.001). Additionally, between dead and surviving patients among OPLL cases, all comorbidities correlated more significantly with death (P 0.001). Furthermore, between surgery and nonsurgery cases of OPLL, diabetes, hypertension, and renal disease (P 0.05) were significantly associated with surgery.Annual incidence of OPLL was 199-371 per 1,025,340 people for 10 years. Diabetes, hypertension, cardiovascular disease, and cerebrovascular disease, except renal disease, correlated significantly with OPLL compared with control cases. Especially, diabetes, hypertension, and renal disease were associated with patients with OPLL who underwent surgery.

VA anomalies in extra- and intraosseous regions of the craniovertebral junction (CVJ) is considered very carefully during the posterior screw fixation for the atlantoaxial instability (AAI). This study aims to compare the incidence and variations of VA anomalies, isthmus and pedicle size of C2 in 100 patients with AAI due to congenital skeletal anomaly (CSA) and acquired disease by using three-dimensional CT angiograms (3D CTA) before surgery. The CSA group contained 48 patients and the acquired disease group consisted of 52. In the CSA group, Os odontoideum was the major cause with 43 patients. The causes of acquired disease were RA in 16 patients and OA in 36 patients. Five patients had the anomalous VA in only CSA group; fenestration 2 patients and persistent first intersegmental (PFIS) artery 3 patients. Between CSA and acquired disease groups, no significant differences were found in the isthmus height, internal height, and pedicle width of C2 except the right internal height that is bigger in CSA group. The high-riding VA (isthmus height4 mm or internal height2 mm) had no significant difference between CSA group (27.1%) and acquired disease group (34.6%). However, in acquired disease group, patients with rheumatoid arthritis had smaller left internal height (4.21 ± 1.63 vs. 5.51 ± 1.83 mm) and pedicle width (4.11 ± 1.05 vs. 5.05 ± 1.66 mm) of C2 than those of patients with degenerative osteoarthritis. Therefore, in the case of atlantoaxial fusion, we should contemplate VA anomaly and the high-riding VA, especially in patients with CSA and RA.

Objective This retrospective case control study aimed to evaluate the feasibility of using Estimation of Physiological Ability and Surgical Stress (E-PASS) and Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (POSSUM) systems in patients undergoing spinal surgical procedures. Degenerative spine disease has increased in incidence in aging societies, as has the number of older adult patients undergoing spinal surgery. Many older adults are at a high surgical risk because of comorbidity and poor general health. Methods We retrospectively reviewed 217 patients who had undergone spinal surgery at a single tertiary care. We investigated complications within 1 month after surgery. Criteria for both skin incision in E-PASS and operation magnitude in the POSSUM system were modified to fit spine surgery. We calculated the E-PASS and POSSUM scores for enrolled patients, and investigated the relationship between postoperative complications and both surgical risk scoring systems. To reinforce the predictive ability of the E-PASS system, we adjusted equations and developed modified E-PASS systems. Results The overall complication rate for spinal surgery was 22.6%. Forty-nine patients experienced 58 postoperative complications. Nineteen major complications, including hematoma, deep infection, pleural effusion, progression of weakness, pulmonary edema, esophageal injury, myocardial infarction, pneumonia, reoperation, renal failure, sepsis, and death, occurred in 17 patients. The area under the receiver operating characteristic curve (AUC) for predicted postoperative complications after spine surgery was 0.588 for E-PASS and 0.721 for POSSUM. For predicted major postoperative complications, the AUC increased to 0.619 for E-PASS and 0.842 for POSSUM. The AUC of the E-PASS system increased from 0.588 to 0.694 with the Modified E-PASS equation. Conclusions The POSSUM system may be more useful than the E-PASS system for estimating postoperative surgical risk in patients undergoing spine surgery. The preoperative risk scores of E-PASS and POSSUM can be useful for predicting postoperative major complications. To enhance the predictability of the scoring systems, using of modified equations based on spine surgery-specific factors may help ensure surgical outcomes and patient safety.

Life-Cycle Assessment has been used extensively in the construction industry to assess the environmental impacts of building materials. Attributional LCA considers processes in a supply chain which allows users to identify a process to improve to minimize the environmental impacts. However, the level of detail adopted in traditional attributional LCA is aggregate, not appropriate for process improvement efforts in the construction project context which is characterized as a complex system. This paper proposes Activity-based LCA (ABLCA) which adopts the methodology of the activity-based costing system to carry out the assessment and analysis of environmental impacts for the life cycle. The research carried out a case study on the curtain wall supply chain. The outcome of inventory analysis for each activity and environmental impact assessment showed the curtain wall supply chain process made an impact on five environmental impact categories: global warming air, acidification air, HH criteria air; eutrophication air, and photochemical smog air. With comparison to the outcome of environmental impact assessment from existing LCA, the proposed management system to investigate environmental impacts was addressed. The proposed ABLCA enables management to develop an environmental-impacts-reduction plan focusing on critical activities.

Study Design Retrospective cohort study. Objective To compare the clinical outcomes of patients undergoing anterior lumbar interbody fusion (ALIF) with or without automated pressure-controlled discography (APCD) before the procedure. Methods Patients (n = 36) who underwent ALIF for lumbar discogenic back pain between 2008 and 2013 and were followed for more than 6 months were enrolled in this study. APCD was performed to identify discogenic back pain. Preoperative x-rays, computed tomography images, and magnetic resonance images were obtained. The intervertebral disc height, type of Modic change, grade of disc degeneration, and fusion rate were determined. Additionally, the presence or absence of high-intensity zone and vacuum disc were checked preoperatively. Clinical evaluation was performed by visual analog scale (0 = no pain, 10 = worst pain imaginable), Oswestry Disability Index (ODI), and 36-Item Short Form Health Survey before surgery and every 6 months postoperatively. Results The average patient age was 53.3 years (range, 31–73 years). The mean follow-up durations were 19.7 months. Seventeen patients (the APCD-ALIF group) underwent ALIF after APCD, and 19 patients underwent ALIF without APCD. The APCD-ALIF group had significantly improved clinical outcomes compared with the control group (visual analog scale score 1.8 ± 1.6 vs. 3.3 ± 2.4; P = 0.039: ODI score 6.7 ± 6.3 vs. 12.1 ± 6.8; P = 0.019). The surgical improvement rate was significantly associated with ODI score (P = 0.005). Conclusions The results of this study confirm that APCD aids surgical outcomes of ALIF in patients with suspected lumbar discogenic pain. We recommend performing APCD before ALIF to confirm lumbar discogenic pain.

Air pollution caused by particulate matter (PM) has become a serious issue, and significant research has focused on managing large stationary emission sources, i.e., the primary sources of PM. Currently, the U.S. Environmental Protection Agency (EPA) Method 201A and ISO 23210 are predominantly employed to measure the PM emissions at large stationary sources. Method 201A is designated as a standard test method in Korea, but it is difficult to measure PM10 and PM2.5 simultaneously owing to the size of the full-set cyclone. In large stationary emission sources, the use of a serial connection of PM10 and PM2.5 cyclones is unsuitable for measurements at conventional sampling ports featuring diameters of approximately 100 mm. Therefore, in this study, PM10 and PM2.5 cyclones were developed to replace the cyclones currently used in Method 201A. The developed cyclones featured a cutoff diameter, which was confirmed by numerical and experimental analyses that were close to Method 201A. Moreover, there was an increase in the stiffness of collection efficiency. The hook adaptor, which is a key accessory used in Method 201A, was found to be applicable to the newly developed cyclones. This alternative method will help reduce the measurement time by simultaneously measuring TSP, PM10, and PM2.5 and eliminates the costs of installing or refurbishing additional sampling ports at existing large stationary sources.

Objective To compare the clinical characteristics of cervical spine trauma in patients with ankylosing spondylitis (AS) and cervical ossification of the posterior longitudinal ligament (OPLL) with those of a control group. Methods A total of 124 patients with cervical spine trauma from January 2004 to December 2013 were reviewed. Fourteen patients were diagnosed with AS and 25 patients were diagnosed with OPLL; 85 patients were controls. C-spine plain radiography, computed tomography, and magnetic resonance imaging were obtained for evaluation of cervical spine trauma. The American Spinal Injury Association impairment scale and Subaxial Cervical Spine Injury Classification were used to evaluate the neurologic status of patients and the fracture mechanism. Results Patients with AS or OPLL had more spinal injuries associated with minor trauma than did the control group. All patients with AS had spinal fracture injuries after cervical spine trauma, but patients with OPLL mostly had spinal cord injuries without bony fractures. After cervical spine trauma, delayed diagnosis occurred in 3 patients with AS (21.4%) and 4 patients with OPLL (15.6%). Improvement from neurologic deficit after treatment showed better outcomes in patients with AS and OPLL than in controls ( P = 0.106). Conclusions Patients with AS or OPLL who had cervical spine trauma showed different characteristics and outcomes than control patients. Proper surgical treatment led to better outcomes in both patients with AS and patients with OPLL than in control patients. Moreover, it is important to thoroughly examine patients with AS or OPLL after cervical trauma so as not to delay diagnosis.

To investigate the clinical characteristics and surgical outcome of revision surgery after first surgical decompression of cervical ossification of posterior longitudinal ligament.A retrospective analysis was performed of 913 patients who underwent surgical decompression of cervical ossification of posterior longitudinal ligament from 1998 to 2012. Of these patients, 35 underwent revision surgery. Neurologic and surgical outcomes, radiologic findings, surgical procedures, and complications were evaluated. Indications for revision surgery were compared between early (≤24 months after the first surgery) and delayed (24 months after the first surgery) revision surgery.There was a higher prevalence of male patients with revision surgery (89%) compared with patients without revision surgery (71.2%, P = 0.033). Preoperative Japanese Orthopaedic Association score was significantly lower in patients with revision surgery (11.5 vs. 12.7, P0.01). Visual analog scale score for neck pain was improved both without revision surgery (from 3.0 to 2.1, P0.001) and with revision surgery (from 3.0 to 2.2, P0.001) patients. Symptomatic residual stenosis was a more frequent cause of revision surgery in early revision surgery than in delayed revision surgery (75% vs. 25%, P0.001). In delayed revision surgery, growth of ossification of posterior longitudinal ligament (50%) was the primary cause of revision surgery.Clinical outcomes (Japanese Orthopaedic Association and visual analog scale scores) of revision surgery are similar to the outcomes of patients who did not require revision surgery. Residual stenosis after the index surgery is the most common indication for early revision surgery. To avoid early revision surgery, surgeons should carefully consider achieving circumferential decompression of the spinal canal during initial surgery.

The progression of scoliosis after fusion surgery is a poor prognostic factor of long-term outcomes in patients with degenerative lumbar stenosis (DLS). In this study we aimed to investigate changes in coronal alignment and identify risk factors related to progression of scoliosis after fusion.There were 540 patients with symptomatic DLS treated by short-segment lumbar fusion surgery. Among them, 50 patients had coronal Cobb angles10° at the final follow-up. Sixteen patients had increases5° (progression group), and 34 patients had increases5° (nonprogression group). Radiologic parameters that may affect the progression of scoliosis were compared.The mean progression of the Cobb angle was 7.92° in the progression group and 1.25° in the nonprogression group. The progression group had significantly longer follow-up periods and a lower preoperative Cobb angle. The apical vertebra (AV) of the major curve was more frequently thoracic in the progression group. Progression of the Cobb angle was correlated with the follow-up period, preoperative Cobb angle, and location of the AV. Multivariate regression analysis showed that progression of the Cobb angle was significantly associated with a lower preoperative Cobb angle, and both facet degeneration of the upper instrumented vertebra at the fusion site and vertebral spur formation on the concave side also appeared to be associated with progression of the Cobb angle.The global magnitude of progression of the Cobb angle after short-segment lumbar fusion surgery in patients with DLS is similar to the natural curve progression of adult degenerative scoliosis.

Background and Objective We investigated a novel method using a 2D convolutional neural network (CNN) to identify superior and inferior vertebrae in a single slice of CT images, and a post-processing for 3D segmentation and separation of cervical vertebrae. Methods The cervical spines of patients (N == 17, 1684 slices) from Severance and Gangnam Severance Hospitals (S/GSH) and healthy controls (N == 24, 3490 slices) from Seoul National University Bundang Hospital (SNUBH) were scanned by using various volumetric CT protocols. To prepare gold standard masks of cervical spine in CT images, each spine was segmented by using conventional image-processing methods and manually corrected by an expert. The gold standard masks were preprocessed and labeled into superior and inferior cervical vertebrae separately in the axial slices. The 2D U-Net model was trained by using the disease dataset (S/GSH) and additional validation was performed by using the healthy control dataset (SNUBH), and then the training and validation were repeated by switching the two datasets. Results In case of the model was trained with the disease dataset (S/GSH) and validated with the healthy control (SNUBH), the mean and standard deviation (SD) of the Dice similarity coefficient (DSC), Jaccard similarity coefficient (JSC), mean surface distance (MSD), and Hausdorff surface distance (HSD) were 94.37%% ± 1.45%, 89.47%% ± 2.55%, 0.33 ± 0.12 mm and 20.89 ± 3.98 mm, and 88.67%% ± 5.82%, 80.83%% ± 8.09%, 1.05 ± 0.63 mm and 29.17 ± 19.74 mm, respectively. In case of the model was trained with the healthy control (SNUBH) and validated with the disease dataset (S/GSH), the mean and SD of DSC, JSC, MSD, and HSD were 96.23%% ± 1.55%, 92.95%% ± 2.58%, 0.39 ± 0.20 mm and 16.23 ± 6.72 mm, and 93.15%% ± 3.09%, 87.54%% ± 5.11%, 0.38 ± 0.17 mm and 20.85 ± 7.11 mm, respectively. Conclusions The results demonstrated that our fully automated method achieved comparable accuracies with inter- and intra-observer variabilities of manual segmentation by human experts, which is time consuming.

Objective In vertebrae with low bone mineral densities pull out strength is often poor, thus various substances have been used to fill screw holes before screw placement for corrective spine surgery. We performed biomechanical cadaveric studies to compare nonaugmented pedicle screws versus hydroxyapatite, calcium phosphate, or polymethylmethacrylate augmented pedicle screws for screw tightening torques and pull out strengths in spine procedures requiring bone screw insertion. Methods Seven human cadaveric T10–L1 spines with 28 vertebral bodies were examined by x-ray to exclude bony abnormalities. Dual-energy x-ray absorptiometry scans evaluated bone mineral densities. Twenty of 28 vertebrae underwent ipsilateral fluoroscopic placement of 6-mm holes augmented with hydroxyapatite, calcium phosphate, or polymethylmethacrylate, followed by transpedicular screw placements. Controls were pedicle screw placements in the contralateral hemivertebrae without augmentation. All groups were evaluated for axial pull out strength using a biomechanical loading frame. Results Mean pedicle screw axial pull out strength compared with controls increased by 12.5% in hydroxyapatite augmented hemivertebrae (P = 0.600) and by 14.9% in calcium phosphate augmented hemivertebrae (P = 0.234), but the increase was not significant for either method. Pull out strength of polymethylmethacrylate versus hydroxyapatite augmented pedicle screws was 60.8% higher (P = 0.028). Conclusions Hydroxyapatite and calcium phosphate augmentation in osteoporotic vertebrae showed a trend toward increased pedicle screw pull out strength versus controls. Pedicle screw pull out force of polymethylmethacrylate in the insertion stage was higher than that of hydroxyapatite. However, hydroxyapatite is likely a better clinical alternative to polymethylmethacrylate, as hydroxyapatite augmentation, unlike polymethylmethacrylate augmentation, stimulates bone growth and can be revised.

Background context Anterior decompression and fusion (ADF) for ossification of the posterior longitudinal ligament (OPLL) is technically demanding and associated with complications. Although various factors affecting clinical outcome have been investigated in posterior decompression, prognostic factors of ADF remain unclear. Purpose The purpose of the study was to identify surgical outcome and prognostic factors of ADF for cervical myelopathy due to OPLL. Study design This was a retrospective case study. Patient sample Between 2005 and 2012, 913 patients underwent decompression surgery for cervical OPLL at our institution. Among them, 131 who underwent ADF and 221 who underwent laminoplasty were enrolled. Inclusion criteria were (1) diagnosis of OPLL; (2) cervical compressive myelopathy; and (3) no trauma, infection, tumor, or previous surgery. We excluded 60 patients with ADF and 157 patients with laminoplasty owing to inadequate follow-up or absence of preoperative myelopathy. Finally, 71 patients with ADF and 64 patients with laminoplasty were enrolled in this study (mean follow-up, 48 vs 41 months). Outcome measures Neurologic assessment was conducted using the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy. Rate of neurologic improvement was calculated by comparing preoperative and postoperative JOA scores. Methods We investigated the effects of such variables as age, gender, body mass index (BMI), presence of diabetes mellitus (DM), smoking history, type of OPLL, shape of the ossified lesion, occupying ratio of OPLL, presence of intramedullary increased signal intensity (ISI) on magnetic resonance imaging (MRI), and sagittal alignment of the cervical spine on surgical outcome. Severity of ISI was classified into three groups based on T2-weighted sagittal MRI as follows: Grade 0, none; Grade 1, ISI limited to one disc level; or Grade 2, ISI beyond one disc level. This work was supported by the 2013 Korea Health Technology R&D Project of the Ministry of Health and Welfare of the Republic of Korea (A120254). Results In patients with an occupying ratio ≥60% or with presence of ISI on MRI, ADF yielded better surgical outcome than laminoplasty. A higher ISI grade (B=−28.5, p=.000) and a higher occupying ratio (B=0.88, p=.04) were significantly associated with a lower recovery rate (R=0.56, p=.006). Older age also was associated with a lower recovery rate. Gender, BMI, presence of DM, smoking history, type of OPLL, shape of the ossified lesion, and cervical alignment were not associated with recovery rate. Conclusion Anterior decompression and fusion has favorable outcome in patients with an occupying ratio ≥60% or with presence of ISI on MRI. Presence of higher ISI grade, higher occupying ratio, and older age were associated with a poor long-term surgical prognosis. Therefore, evaluating ISI and occupying ratio on preoperative MRI is important for selecting the appropriate surgical approach and for predicting clinical outcome after surgery for cervical compressive myelopathy due to OPLL.

Objective Transarticular facet screws restore biomechanical stability to the cervical spine when posterior cervical anatomy has been compromised. This study compares the more recent, less invasive, and briefer transarticular facet screw system without rods with the lateral mass screw system with rods. Methods For this study, 6 human cervical spines were obtained from cadavers. Transarticular facet screws without rods were inserted bilaterally into the inferior articular facets at the C5-C6 and C5-C6-C7 levels. Lateral mass screws with rods were inserted bilaterally at the same levels using Magerl's technique. All specimens underwent range of motion (ROM) testing by a material testing machine for flexion, extension, lateral bending, and axial rotation. Results Both fixation methods, transarticular facet screws without rods and lateral mass screws with rods, reduced all ROM measurements and increased spinal stiffness. No statistically significant differences between the 2 stabilization methods were found in ROM measurements for 1-level insertions. However, in 2-level insertions, ROM for the nonrod transarticular facet screw group was significantly increased for flexion-extension and lateral bending. Conclusions Transarticular facet screws without rods and lateral mass screws with rods had similar biomechanical stability in single-level insertions. For 2-level insertions, transarticular facet screws without rods are a valid option in cervical spine repair.

Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Medical Research Institute, Busan, epublic of Korea Department of Nuclear Medicine, Pusan National University Hospital, Pusan National University School of Medicine and Medical Research Institute, usan, Republic of Korea Department of Radiology, Pusan National University Hospital, Pusan National University School of Medicine and Medical Research Institute, Busan, epublic of Korea

Background context Heterotopic ossification (HO) is defined as a formation of bone outside the skeletal system. The reported HO occurrence rate in cervical artificial disc replacement (ADR) is unexpectedly high and is known to vary. However, the predisposing factors for HO in cervical ADR have not yet been elucidated. Purpose Investigation of the predisposing factors of HO in cervical arthroplasty and the relationship between degeneration of the cervical spine and HO occurrence. Study design Retrospective study to discover predisposing factors of HO in cervical arthroplasty. Patient sample A total of 170 patients who underwent cervical ADR were enrolled including full follow-up clinical and radiologic data. Outcome measures Radiologic outcomes were assessed by identification of HOs according to McAfee's classifications. Methods This study enrolled a total of 170 patients who underwent cervical ADR. Pre-existing degenerative change included anterior or posterior osteophytes, ossification of the anterior longitudinal ligament, posterior longitudinal ligament, or ligamentum nuchae. The relationships between basic patient data, pre-existing degenerative change, and HO were investigated using linear logistic regression analysis. Results Among all 170 patients, HO was found in 69 patients (40.6%). Among the postulated predisposing factors, only male gender and artificial disc device type were shown to be statistically significant. Unexpectedly, preoperative degenerative changes in the cervical spine exerted no significant influence on the occurrence of HOs. The odds ratio of male gender compared with female gender was 2.117. With regard to device type, the odds ratios of Mobi-C (LDR medical, Troyes, France) and ProDisc-C (Synthes, Inc., West Chester, PA, USA) were 5.262 and 7.449, respectively, compared with the Bryan disc. Conclusions Definite differences in occurrence rate according to the gender of patients and the prosthesis type were identified in this study. Moreover, factors indefinably expected to influence HO in the past were not shown to be risk factors thereof, the results of which may be meaningful to future studies.

Changes in workforce demographics have led to the need for more sophisticated approaches to addressing the safety requirements of the construction industry. Despite extensive research in other industry domains, the construction industry has been passive in exploring the impact of a color scheme; perception-related accidents have been effectively diminished by its implementation. The research demonstrated that the use of appropriate color schemes could improve the actions and psychology of workers on site, thereby increasing their perceptions of potentially dangerous situations. As a preliminary study, the objects selected by rigorous analysis on accident reports were workwear, safety net, gondola, scaffolding, and safety passage. The colors modified on site for temporary facilities were adopted from existing theoretical and empirical research that suggests the use of certain colors and their combinations to improve visibility and conspicuity while minimizing work fatigue. The color schemes were also tested and confirmed through two workshops with workers and managers currently involved in actual projects. The impacts of color schemes suggested in this paper are summarized as follows. First, the color schemes improve the conspicuity of facilities with other on site components, enabling workers to quickly discern and orient themselves in their work environment. Secondly, the color schemes have been selected to minimize the visual work fatigue and monotony that can potentially increase accidents.

Hepatitis B virus (HBV) infection in Asian American Pacific Islanders (AAPIs) is an important health problem that must be recognized and addressed by the U.S. public health policy. However, AAPIs have been to a large degree invisible in public health data and debates and their interests have been disregarded. Moreover, an estimation of HBV infection rates reported from the National Nutritional and Health Survey Examinations III was 1.25 million; however, an estimate based on AAPI-targeted studies places the number at almost 2 million. This article discusses the perils of application of textbook methods of sampling coverage, selection, and nonresponse in studies related to AAPIs and the importance to note that some rapidly increasing racial/ethnic groups such as AAPIs have linguistic and cultural differences and these differences often cause such groups to be omitted from data collection.

Background Preservation of segmental motion and avoidance of adjacent segment degeneration are common theoretical advantages of cervical arthroplasty and ACF. In patients with unilateral cervical radiculopathy, both procedures have shown good clinical results; but there are currently no proven comparative biomechanical results. This study was designed to compare the biomechanical effect of cervical arthroplasty and ACF and to propose optimal inclusion criteria for each surgery. Methods Among the patients with unilateral cervical radiculopathy, 15 patients who underwent arthroplasties using the Bryan disk (Medtronic Sofamor Danek, Memphis, TN) and 13 patients who underwent ACFs were retrospectively analyzed. A radiological assessment and comparative analysis of the biomechanical results (sagittal alignment, ROM, and disk height) between the 2 procedures were performed. Results Both procedures showed similar but contrary biomechanical results, with the exception of the disk height. Anterior cervical foraminotomy has been shown to restrict motion in the segmental and adjacent segment motion and a tendency toward restoration of lordosis. Anterior cervical foraminotomy caused a significant decrease in disk height after surgery, whereas arthroplasty caused no change in height. The restoration of disk height was achieved by arthroplasty, especially in patients with spondylotic radiculopathy. Conclusions In unilateral cervical radiculopathy, arthroplasty and ACF provided favorable clinical and radiological outcomes. However, we should understand the different biomechanical backgrounds resulting in common advantages. To achieve the fundamental goal of the procedures, the patients' biomechanical abnormalities should be elucidated and treated by the optimal procedure.

Aluminum curtain wall system is commonly used in high-rise residential complex. For the energy-efficient curtain wall system, the insulation performance of the fastening unit, which enjoins the curtain wall unit to the slab, should be improved because in Korea, hot water pipes for radiant heating are typically installed on the slab in residential buildings. However, this fastening unit composed of metals with high thermal conductivity, acts as a thermal bridge that increases heat loss. Therefore, in this study, we aim to develop a more effective insulation method for the fastening unit. Three alternative fasteners coated with urethane foam and insulation paint were selected (Case 1: using the existing fastener; Case 2: coating the upper part of fastener with urethane foam; Case 3: coating the entire surface of fastener with insulation paint; Case 4: coating the upper part of fastener with urethane foam and the lower part with insulation paint). The heat loss and economical efficiency of each case were analyzed through the three-dimensional annual transient heat transfer simulation and payback period method, respectively. Case 4, compared to Case 1, was found to show the best performance of reducing the annual heat loss by 8.14%. From an economical efficiency perspective, however, Case 2 was found to have the shortest payback period of 2.27years.

The aim of this study is to reveal the oscillatory change and subjective arousal level during simulated driving using synthetic aperture magnetometry (SAM). Subjects were instructed to perform the driving simulation task using a steering wheel, accelerator and brake pedals. The subjective arousal level was estimated using a visual analog scale. The subjective arousal level was reduced and the activities of theta band (4–8 Hz) in frontal areas were increased as driving time advanced. It is well known that the theta wave increases during rest state. Our previous studies also demonstrated that pseudo- Z value in the theta band inversely correlates with subjective arousal level. The present study demonstrated that this relation holds true even during driving state.

As-cast microstructure of Mg-rich Mg(68)Zn(28)Y(4) has been investigated by a detailed transmission electron microscopy study. The as-cast Mg(68)Zn(28)Y(4) alloy consisted of three different types of phases: 10-20 m size primary solidification phase, dendritic phase grown from the primary phase and a eutectic structure formed at the later stage of solidification. The primary solidification phase has an icosahedral structure with a large degree of phason strain. 1/1 rhombohedral approximant phase with lattice parameters a=27.2 A and =63.43 degrees is first observed in Mg-Zn-Y system. The rhombohedral structure can be obtained by introducing phason strain in the six-dimensional face centered hyper-cubic lattice. The decagonal phase nucleates with orientation relationship with the icosahedral phase, and Mg(4)Zn(7) nucleates with orientation relationship with the decagonal phase, indicating a close structural similarity between the three phases. Gradual depletion of Y during solidification plays an important role in heterogeneous nucleation of decagonal and Mg(4)Zn(7) phases from icosahedral and decagonal phases, respectively.

Highly effective nurse practitioners in managed care settings may understand the basic concept of managed care without appreciating how the context of managed care impacts their practice. This article discusses the concept of managed care within the context of 4 managed care strategies. In developing this paper, our goals were first, to describe contracts, incentives, management, and medical necessity as managed care strategies and second, to discuss some of the ways these strategies can significantly impact nurse practitioner practice. Illustrative practice examples are used to suggest that those nurse practitioners who understand managed care, both as a theoretical concept and as a context for practice, may find that they are better able to develop innovative ways to meet the needs of their patients.

Structural applications of monolithic icosahedral phase (I-phase) materials have been limited by the brittleness of I-phases. Composite material design, including a ductile phase, can be a solution for the structural applications of the I-phase materials. Two phase microstructures, including thermodynamically stable I-phase, are studied in the Mg-rich corner of the alloy system Mg–Zn–Y. An (I-phase+α-Mg) eutectic microstructure is reported for the first time in the as-cast samples. By controlling thermal processing procedures, a very different (I-phase+α-Mg) microstructure from the eutectic microstructure can be developed, expanding the microstructural options available for the structural composite materials, comprising the I-phase and α-Mg solid solution.

For the purpose of enhancing the electrochemical performance of a cathode in a Li-ion battery, composites with a mechanically blended mixture of Cu-base metallic glass, LiCoO 2 , and carbon black were developed. The cathodes were synthesized by warm rolling in the supercooled liquid region of the metallic glass by adjusting the reduction ratio to possess pores to enlarge the contact area to the electrolyte. The cyclic voltammetry tests of the cathodes showed good electrochemical reaction with high durability. The effective bonding between the metallic glass and LiCoO 2 developed by viscous flow of the metallic glass, and high capacity of absorbing the hydrostatic strain which is being occurred during the reaction in the metallic glass, can sustain the electrochemical reaction for a long time.