Occipital nerve stimulator systems: Review of complications and surgical techniques

Introduction: Stimulation of the occipital nerves is becoming more widely accepted in the treatment of occipital neuritis and migraine disorders. Objective: Presently, equipment available for spinal cord stimulation is adapted for insertion into the subcutaneous space over the occipital nerves. Many technical factors need to be reassessed to optimize the therapy. Methods: We performed a retrospective review of patients implanted from 2003 to 2007 at a single center. We aimed to analyze the rate of surgical complications related to implantation technique. A total of 28 patients were present for analysis. Patients were followed up to 60 months with a mean follow-up of 21 months. Results: There is a 32% revision rate for electrode migration or displacement, 3.6% removal rate for infection, and a 21% removal rate for lack of efficacy. Although not well studied secondary to small patient populations, this was consistent with a review of the literature which demonstrated a 10-60% revision rate. Other factors such as anchoring strategy, strain relief, and battery location were all considered in the analysis and will be presented. A major determination was that use of a second incision with an additional strain relief loop had only a 10% revision rate of the lead while those without this additional strain relief loop had a 62.5% revision rate. Conclusion: Many technical factors need to be addressed for optimization of occipital nerve stimulation

Endoscopic rhizotomy for chronic lumbar zygapophysial joint pain.

BACKGROUND: Chronic lumbar zygapophysial joint pain is a common cause of chronic low back pain. Percutaneous radiofrequency ablation (RFA) is one of the effective management options; however, the results from the traditional RFA need to be improved in certain cases. The aim of this study is to investigate the effect of percutaneous radiofrequency ablation under endoscopic guidance (ERFA) for chronic low back pain secondary to facet joint arthritis. METHODS: This is a prospective study enrolled 60 patients. The cases were randomized into two groups: 30 patients in the control group underwent traditional percutaneous radiofrequency ablation, others underwent ERFA. The lumbar visual analog scale (VAS), MacNab score, and postoperative complications were used to evaluate the outcomes. All outcome assessments were performed at postoperative 1 day, 1 month, 3 months, 6 months, and 12 months. RESULTS: There was no difference between the two groups in preoperative VAS (P \u3e 0.05). VAS scores, except the postoperative first day, in all other postoperative time points were significantly lower than preoperative values each in both groups (P \u3c 0.05). There was no significant difference between the two groups in VAS at 1 day, 1 month, and 3 months after surgery (P \u3e 0.05). However, the EFRA demonstrated significant benefits at the time points of 3 months and 6 months (P \u3e 0.05). The MacNab scores of 1-year follow-up in the ERFA group were higher than that in the control group (P \u3c 0.05). The incidence of complications in the ERFA group was significantly less than that in the control group (P \u3c 0.05). CONCLUSIONS: ERFA may achieve more accurate and definite denervation on the nerves, which leads to longer lasting pain relief

Relationship between metabolic syndrome and its components and cardiovascular disease in middle-aged and elderly Chinese population:a national cross-sectional survey

OBJECTIVES: To assess the relationship between metabolic syndrome (MetS) and its components and cardiovascular disease (CVD) according to different criteria of MetS, as well as whether the estimated association between MetS and CVD was affected by different definitions of MetS among the Chinese population. DESIGN: Population-based, cross-sectional study. SETTING: Data were from a large-scale national stroke screening survey, China National Stroke Screening and Prevention Project. PARTICIPANTS: A nationally representative sample of 109 551 Chinese adults aged ≥40 years in 2014-2015 were included. PRIMARY OUTCOME MEASURES: CVD conditions (stroke, coronary heart disease (CHD) and atrial fibrillation (AF)) diagnosed by clinicians were self-reported. RESULTS: ORs after adjusting for CHD, stroke, AF and CVD in those with MetS using the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criterion were 1.56 (95% CI 1.48 to 1.63), 1.23 (95% CI 1.17 to 1.30), 1.14 (95% CI 1.08 to 1.21) and 1.40 (95% CI 1.35 to 1.45); 1.51 (95% CI 1.44 to 1.58), 1.20 (95% CI 1.14 to 1.26), 1.09 (95% CI 1.04 to 1.15) and 1.34 (95% CI 1.29 to 1.38) with the American Heart Association/National Heart, Lung, and Blood Institute criterion; and 1.41 (95% CI 1.35 to 1.48), 1.24 (95% CI 1.19 to 1.30), 1.12 (95% CI 1.06 to 1.18) and 1.31 (95% CI 1.27 to 1.35) with the International Diabetes Federation criterion, respectively. Elevated blood pressures were all highly related to the prevalence of stroke and AF, and reduced high-density lipoprotein-cholesterol was associated with a higher OR for CHD than other individual components of MetS. CONCLUSIONS: MetS is significantly associated with CVD, and the prevalence of CVD was more evident when MetS was defined according to the NCEP ATP III criterion. Developing effective public health strategies for the prevention, detection and treatment of MetS should be an urgent priority to reduce the burden of CVD in China

Reactive Laser Synthesis of Ultra-high-temperature Ceramics HfC, ZrC, TiC, HfN, ZrN, and TiN for Additive Manufacturing

Ultra-high-temperature ceramics (UHTCs) are optimal structural materials for applications that require extreme temperature resilience, resistance to chemically aggressive environments, wear, and mechanical stress. Processing UHTCs with laser-based additive manufacturing (AM) has not been fully realized due to a variety of obstacles. In this work, selective laser reaction sintering (SLRS) techniques were investigated for the production of near net-shape UHTC ceramics such as HfC, ZrC, TiC, HfN, ZrN, and TiN. Group IV transition metal and metal oxide precursor materials were chemically converted and reaction-bonded into layers of UHTCs using single-step selective laser processing in CH4 or NH3 gas that might be compatible with prevailing powder bed fusion techniques. Conversion of either metals (Hf, Zr and Ti) or metal oxides (HfO2, ZrO2, and TiO2) particles was first investigated to examine reaction mechanisms and volume changes associated with SLRS of single-component precursor systems. SLRS processing of metal or metal oxide alone produced near stoichiometric UHTC phases with yields up to 100 wt% total for carbides and nitrides. However, for single component precursors, gas-solid reactivity induced volumetric changes resulted in residual stresses and cracking in the product layer. To mitigate conversion-induced stresses, composite metal/metal oxide precursors were employed to compensate for the volume changes of either the metal (which expands during conversion) or the metal oxide precursor (which contracts).Comment: 58 pages, 17 figure

Prevalence and Risk Factors for Dyslipidemia Among Adults in Rural and Urban China: Findings From the China National Stroke Screening and Prevention Project (CNSSPP)

Background: Dyslipidemia is a modifiable risk factor for cardiovascular disease (CVD). We investigated the prevalence and associated risk factors of dyslipidemia- raised total cholesterol (TC), raised triglycerides (TG), raised low-density lipoprotein (LDL-C), low high-density lipoprotein (HDL-C), and raised non-high-density lipoprotein (non-HDL-C) in rural and urban China. Methods: We analyzed data from 136,945 participants aged 40-100 years of the CNSSPP project for 2014. Dyslipidemia was defined by the NCEP-ATP III and the 2016 Chinese guidelines for the management of dyslipidemia in adults. Complete data on demographic, metabolic and lifestyle characteristics were used. Chi-square tests and multivariable logistic regression were used to obtain age- and sex-adjusted prevalence and risk factors for dyslipidemia among participants. Results: A total of 53.1% participants lived in rural areas. The prevalence of dyslipidemia was similar among rural and urban participants (43.2% vs. 43.3%). Regarding the components of dyslipidemia: urban compared with rural participants had a higher prevalence of low HDL-C (20.8% vs. 19.2%), whereas the prevalence of raised LDL-C (7.8% vs. 8.3%), raised TC (10.9% vs.11.8%) and raised non-HDL-C (10.0% vs. 10.9%) were lower in urban residents, (all p \u3c 0.001). Women were more likely to have raised TC than men (adjusted OR [AOR] =1.83, 95% confidence interval [CI]:1.75-1.91), raised LDL-C (AOR = 1.55, 95% CI: 1.47-1.63) and high non-HDL-C (AOR = 1.52 95% CI: 1.45-1.59) (all p \u3c 0.001). Compared with rural, urban participants had higher odds of dyslipidemia: low HDL-C (AOR = 1.04, 95% CI: 1.01-1.07), and raised TG (AOR = 1.06, 95% CI: 1.04-1.09). Hypertension and current drinker were less likely to get low HDL-C with AOR 0.93 (95% CI: 0.90-0.96) and AOR 0.73 (95% CI: 0.70-75), respectively. Overweight, obesity, central obesity and diabetes had higher odds of all dyslipidemias (p \u3c 0.001). Conclusions: Low HDL-C was higher in urban areas, whereas the remaining dyslipidemia types were more common in rural areas. Dyslipidemia was more common in women in both areas of residence. Overweight, obesity, central obesity and diabetes were associated with dyslipidemias. The need to intensify intervention programs to manage dyslipidemia and risk factors should be prioritized

Use of High-Resolution Ultrasound to Guide Alcohol Neurolysis for Chronic Pain

BACKGROUND: The diagnosis and treatment of neuropathic pain is often clinically challenging, with many patients requiring treatments beyond oral medications. To improve our percutaneous treatments, we established a clinical pathway that utilized ultrasound (US) guidance for steroid injection and alcohol ablation for patients with painful neuropathy. OBJECTIVES: To describe a collaborative neuropathy treatment pathway developed by a neurosurgeon, pain physicians, and a sonologist, describing early clinical experiences and patient-reported outcomes. STUDY DESIGN: A retrospective case series was performed. METHODS: Patients that received percutaneous alcohol ablation with US guidance for neuropathy were identified through a retrospective review of a single provider\u27s case log. Demographics and treatment information were collected from the electronic medical record. Patients were surveyed about their symptoms and treatment efficacy. Descriptive statistics were expressed as medians and the interquartile range ([IQR]; 25th and 75th data percentiles). Differences in the median follow-up pain scores were assessed using a Wilcoxon signed-rank test. RESULTS: Thirty-five patients underwent US-guided alcohol ablation, with the average patient receiving one treatment (range: 1 to 2), having a median duration of 4.8 months until reinjection (IQR: 2.9 to 13.1). The median number of steroid injections that individuals received before US-guided alcohol ablation was 2 (IQR: 1 to 3), and the median interval between steroid injections was 3.7 months (IQR: 2.0 to 9.6). Most (20/35 [57%]) patients responded to the survey, and the median pain scores decreased by 3 units (median: -3, IQR: -6 to 0; P \u3c 0.001) one week following the alcohol ablation. This pain reduction remained significant at one month (P \u3c 0.001) and one year (P = 0.002) following ablation. Most (12/20 [60%]) patients reported that alcohol ablation was more effective in improving their pain than oral pain medications. LIMITATIONS: Given the small sample size, treatment efficacy for alcohol neurolysis cannot be generalized to the broader population. CONCLUSIONS: US-guided percutaneous treatments for neuropathic pain present a growing opportunity for interprofessional collaboration between neurosurgery, clinicians who treat chronic pain, and sonologists. US can provide valuable diagnostic information and guide accurate percutaneous treatments in skilled hands. Further studies are warranted to determine whether a US-guided treatment pathway can prevent unnecessary open surgical management

A novel progressive grid generation method for free-form grid structure design and case studies

Due to its high structural efficiency and aesthetics, free-form grid structures have been widely used in various public structures. However, it is neither a convenient nor an obvious task for engineers to create a discrete grid on a free-form surface that manifests the architect's intent. This paper presents an efficient design approach based on Coulomb's law to generate well-shaped and fluent grids for free-form grid structural design. In the method, nodes of the grid structure are considered to be interacting particles in an electric field and are added to the surface in a progressive way. The nodal position is determined by Monte Carlo simulation and the grid is generated by connecting the particles that are already in equilibrium. According to the different ways of adding particles, two variations of the method are introduced in this paper: point-based progressive method (PBPM), and curve-based progressive method (CBPM). Case studies are provided to demonstrate the effective execution of the proposed method. The results show that the proposed method can effectively avoid mapping distortion and generate grids with regular shape and fluent lines to meet the aesthetic requirements. Furthermore, the proposed method provides flexible control over the direction and size of the grid, which gives architects a more flexible choice

The rates and the determinants of hypertension according to the 2017 definition of hypertension by ACC/AHA and 2014 evidence-based guidelines among population aged ≥40 years old

Background : In November 2017, the American College of Cardiology/American Heart Association (ACC/AHA) updated their definition of hypertension from 140/90 mm Hg to 130/80 mm Hg. Objectives : We sought to assess the situation of hypertension and the impact of applying the new threshold to a geographically and ethnically diverse population. Methods : We analyzed selected data on 237,142 participants aged ≥40 who had blood pressure taken for the 2014 China National Stroke Screening and Prevention Project. Choropleth maps and logistic regression analyses were performed to estimate the prevalence, geographical distribution and risk factors of hypertension using both 2017 ACC/AHA guidelines and 2014 evidence-based guidelines. Results : The present cross-sectional study showed the age- and sex-standardized prevalence of hypertension was 37.08% and 58.52%, respectively, according to 2014 evidence-based guidelines and 2017 ACC/AHA guidelines. The distribution of hypertension and risk factors changed little between guidelines, with data showing a high prevalence of hypertension around Bohai Gulf and in south central coastal areas using either definition. The age- and sex-standardized prevalence of newly labeled as hypertensive was 21.44%. Interestingly, the high prevalence region of newly labeled as hypertensive was found in the north China. Conclusion : The prevalence of hypertension increased significantly on 2017 ACC/AHA guidelines compared to the prevalence when using 2014 evidence-based guidelines, with high prevalence areas of newly labeled as hypertensive now seen mainly in north China. There need to be correspondingly robust efforts to improve health education, health management, and behavioral and lifestyle interventions in the north

Implementing opportunistic spectrum access in LTE-Advanced

Long term evolution advanced (LTE-A) has emerged as a promising mobile broadband access technology aiming to cope with the increasing traffic demand in wireless networks. However, the enhanced spectral efficiency offered by LTE-A may become futile without a better management of scarce and overcrowded electromagnetic spectrum. In this sense, cognitive radio (CR) has been proposed as a potential solution to the problem of spectrum scarcity. Among all the mechanisms provided by CR, opportunistic spectrum access (OSA) aims at a dynamic and seamless use of certain licensed bands provided the licensee is not harmfully affected. This operation requires spectral awareness in order to avoid interferences with licensed systems. In spite of implementing some spectrum sensing mechanisms, LTE-A technology lacks other tools that are needed in order to improve the knowledge of the radio environment. This work studies the adoption of a Geo-located data base (Geo-DB) that cooperatively retrieves and maintains information regarding the location of unutilized portions of spectrum potentially available for OSA. Moreover, the potential benefit of this LTE-compliant OSA solution is evaluated using a calibrated simulation tool, by which numerical results allow us to optimally configure the system and show that the proposed opportunistic system is able to significantly improve its performance.The authors would like to thank the funding received from the Ministerio de Ciencia e Innovacion within the Project number TEC2011-27723-C02-02 and from the Ministerio de Industria, Turismo y Comercio TSI-020100-2011-266 funds. This article had been written in the framework of the CELTIC project CP08-001 COMMUNE. Study by X. Gelabert is funded by the BP-DGR 2010 scholarship (ref. 00192). 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