Measuring the performance of patient-specific solutions for minimally invasive transforaminal lumbar interbody fusion surgery

Pre-surgical planning using 3D-printed BioModels enables the preparation of a “patient-specific” kit to assist instrumented spinal fusion surgery. This approach has the potential to decrease operating time while also offering logistical benefits and cost savings for healthcare. We report our experience with this method in 129 consecutive patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) over 27 months at a single centre and performed by a single surgeon. Patient imaging and surgical planning software were used to manufacture a 3D-printed patient-specific MIS TLIF kit for each patient consisting of a 1:1 scale spine BioModel, stereotactic K-wire guide, osteotomy guide, and retractors. Pre-selected pedicle screws, rods, and cages were sourced and supplied with the patient-specific kit. Additional implants were available on-shelf to address a size discrepancy between the kit implant and intraoperative measurements. Each BioModel was used pre-operatively for surgical planning, patient consent and education. The BioModel was sterilised for intraoperative reference and navigation purposes. Efficiency measures included operating time (153 ± 44 min), sterile tray usage (14 ± 3), fluoroscopy screening time (57.2 ± 23.7 s), operative waste (19 ± 8 L contaminated, 116 ± 30 L uncontaminated), and median hospital stay (4 days). The pre-selected kit implants exactly matched intraoperative measurements for 597/639 pedicle screws, 249/258 rods, and 46/148 cages. Pedicle screw placement accuracy was 97.8% (625/639) on postoperative CT. Complications included one intraoperative dural tear, no blood products administered, and six reoperations. Our experience demonstrates a viable application of patient-specific 3D-printed solutions and provides a benchmark for studies of efficiency in spinal fusion surgery.     

显微血管减压术治疗286例面肌痉挛的临床疗效

目的探讨显微血管减压术治疗面肌痉挛的疗效及预后。方法回顾采用显微血管减压术治疗的286例面肌痉挛患者,分析其临床表现、手术效果和并发症之间的关系,并于术后半年进行电话随访和来院复查,分析其长期的疗效。结果 286例患者起病时均表现为单侧面部肌肉阵发性、不自主、无痛性抽搐,随病程延长呈逐渐加重的趋势。本组术中均能见到有动脉或静脉血管异常而压迫面神经根出脑干处。术后随访6月至1年,230例症状完全缓解,52例明显减轻,4例手术无效。结论显微血管减压术是治疗面肌痉挛的一种安全而有效的手术方法。     

血管内栓塞治疗顽固性鼻出血的中远期疗效分析

目的探讨经血管内栓塞治疗顽固性鼻出血的中远期疗效,评价其临床应用价值。资料与方法搜集2005年3月至2010年3月采用血管内栓塞治疗顽固性鼻出血的患者52例,回顾分析其临床资料及随访结果。结果 52例中,失访8例,随访44例(3~60个月,平均42个月)。鼻咽部血管瘤19例,其中2例5年内复发出血;鼻肉瘤2例,其中1例3个月后因基础疾病诱发鼻腔大出血死亡;鼻咽癌6例,其中2例术后1个月复发出血,第二次栓塞后随访3个月无复发,6个月后因基础疾病复发大出血死亡;高血压6例,其中2例术后1个月复发大出血,常规治疗后止血,术后5年内血压升高时即间断少量渗血;鼻中隔术后4例,栓塞后无出血;无诱因出血7例,其中1例1个月内饮酒诱发鼻出血;36例随访3~60个月均无复发出血。短期止血率100%(≤7天),中远期止血率82%(36/44)。结论血管内栓塞治疗顽固性鼻出血短期疗效显著;根据基础疾病不同,其中远期疗效差异明显;栓塞材料的选择及介入超选择插管技术对中远期疗效有重要意义。     

Efficiency and administrative costs in primary care

We use a formal model to examine the implications of endogenous managerial effort for the interpretation and estimation of efficiency in health care organisations. The model is applied to investigate the doubling of the cost of administering primary care in England in real terms between 1989/1990 and 1994/1995. The main cost determinant was the number of general practitioners (GPs), and there were economies of scale but not of scope. Fund-holding had a positive but small effect on administrative costs, so that the recent abolition of fund-holding may do little to reduce primary care administrative costs. After allowing for changes in the numbers of primary care practitioners, the quality of primary care and the extent of fund-holding, most of the increase in costs was unexplained, and may reflect additional but unmeasured increases in the administrative burden associated with the 1990 reforms. There was little variation in relative efficiency across areas.     

Über Wirksamkeit,Dosisrelation und Depoteffekt eines synthetischen Polypeptids mit ACTH-Wirkung

Zusammenfassung In der vorliegenden Untersuchung werden die Wirksamkeit, die Dosisrelation und der Depoteffekt eines synthetischen depot-^1–24-tetracosactide (Cortrophine-S-Deport Organon^®) und eines nach herkömmlicher Weise hergestellten Depot-ACTH-Präparates (Cortrophine-Z Organon^®) verglichen. Als Parameter gilt die Ausscheidung des freien Cortisols im Harn. Bei einer angenommenen Relation von 100 IE Cortrophine-Z gleich 1 mg Cortrosyn-Depot zeigt das synthetische Präparat bei vollwertiger adrenocorticotroper Wirkung einen Gesamtstimulationseffekt von 70,2% desjenigen des herkömmlichen Präparates. Dabei ist der Initialphaseneffekt bei beiden Präparaten gleich. In der sogenannten Stimulationserhaltungsphase und in der Abklingphase des Depoteffektes zeigen sich Unterschiede zugunsten des herkömmlichen Präparates. Es errechnet sich eine Dosisrelation von 100 IE Cortrophine-Z gleich 1,42 mg Cortrosyn-Depot, wobei diskutiert wird, ob es sich hier in der Tat um ein Dosisproblem oder um ein Problem der Depotstabilität handelt.

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Efficiency, dose relation and depot effect of a depot-^1–24-tetracosactide

This paper reports on a comparative study on a synthetic depot-^1–24-tetracosactide (Cortrophine-S-Depot Organon^®) and an extractive ACTH-depotpreparation (Cortrophine-Z Organon^®); the factors studied were efficiency, dose relation, and depot effect. The parameter used was the excretion of free cortisol in the urine. Assuming a dose relation of 100 I.U. of extractive ACTH equal to 1 mg of the synthetic preparation, our results show, that the synthetic preparation evokes a stimulative effect which equals 70.2% of that of the extractive ACTH. The difference was especially observed in the decreasing phase of the depot effect. The true dose relation calculated with regard to the parameter used, was 100 I.U. extractive ACTH to 1.42 mg of the synthetic tetracosactide. However, it has to be considered whether the difference between the two preparations regarding the effect of stimulation is in fact a question of unequal doses or a question of the stability of the depot itself.

Die Untersuchung wurde im Rahmen einer Beihilfe der Deutschen Forschungsgemeinschaft, Bad Godesberg, durchgeführt (Sto 45/8)     

Cognitive Efficiency in Alcoholics and Polysubstance Abusers

Previous studies have found alcoholics to be impaired on tests of cognitive efficiency. However, it is unclear to what extent individuals who abuse drugs in addition to alcohol exhibit similar deficits. To answer this question, 63 healthy control subjects were compared with 40 individuals who abused alcohol only, 24 individuals who abused alcohol and stimulants, 16 individuals who abused alcohol and marijuana, and 41 individuals who abused alcohol and depres-sants/narcotics, or alcohol and two or more other drugs. All subjects were administered tests of Short-term memory, spatial orientation, visual-spatial perception, and problem-solving. Results from the study indicated that control subjects and individuals who abused both alcohol and marijuana performed significantly better than the other groups on most tests. These results were not attributable to differences on measures of affect or chronicity of alcohol consumption.     

Utility of a dynamic termination criterion in the ZEST adaptive threshold method

Bayesian adaptive threshold procedures may be run for a fixed number of trials, or may be stopped when the calculated confidence interval for the threshold reaches a selected limit (a dynamic termination criterion). This study used Monte-Carlo simulations to determine whether the confidence interval is a useful predictor of errors in the estimated threshold. No difference was found between the distribution of errors in a fixed trial procedure versus a dynamically terminated procedure of the same average number of trials. In addition, the width of the confidence interval failed to usefully predict observer variability arising from a shallow psychometric function slope or increased false positive response probabilities. This study suggests that dynamic termination criteria are of little use in Bayesian adaptive threshold procedures.     

Muscle efficiency: the controversial role of elasticity and mechanical energy conversion in stretch-shortening cycles

The analysis of muscle efficiency was performed on a variety of simulated muscle stretch-shortening cycles of in situ rat gastrocnemius muscle. The processes of biochemical energy conversions (phosphorylation and contraction-coupling) and mechanical conversions (internal work to external work) were incorporated in the efficiency calculations. Metabolic cost was determined using a simple linear model. Special attention was drawn to the interacting roles of series elastic compliance and contraction dynamics. The results showed that series elastic compliance affected the efficiency of muscle contraction to a great extent. Stiff muscle was well designed to perform efficient contractions in which muscle merely shortened while active. Compliant muscle performed best in true stretch-shortening contractions utilising the storage and release of series elastic energy effectively. However, both stiff and compliant series elastic elements showed similar optimal muscle efficiency values in shortening contractions and stretch-shortening contractions, respectively. The findings indicate that the storage and re-utilisation of series elastic energy does not enhance overall muscle efficiency, but that optimal efficiency is obtained by a proper design of the muscle with regard to the dynamics of the movement task. Furthermore, it was found that although biochemical efficiency determined the feasible range of muscle efficiency, mechanical work conversions had the strongest influence on the exact value of overall muscle efficiency in stretch-shortening contractions. Electronic Publication     

Body composition,work capacity,and work efficiency of active and inactive young men

On 46 healthy young men, of whom 18 took part in strenuous sport at least once a week, height, weight, total body fat (as % of body mass) and lean body mass (LBM) were determined. The subjects performed submaximal exercise on a bicycle ergometer and climbing on an upwardly inclined treadmill at work loads of 60, 110, and 140 watts. Oxygen consumption ( ), respiratory quotient (RQ), energy expenditure (), and heart rate (f _H) were measured at rest and at each work load, and maximum oxygen intake ( max) and physical work capacity (PWC₁₅₀, PWC₁₇₀) were calculated.Anthropometric parameters did not differ significantly between sportsmen and sedentary subjects. max, PWC₁₅₀, and PWC₁₇₀ had higher correlations with LBM than with the other anthropometric parameters. max expressed in terms of LBM (ml/kg LBM/min) was the parameter which showed the clearest distinction between sportsmen and sedentary individuals. The sportsmen had higher max on the treadmill test than on the bicycle ergometer. PWC₁₅₀ and PWC₁₇₀ were higher on the bicycle than on the treadmill and had high correlations with max. Work efficiency was of the same order in both groups and showed negative correlation with the degree of obesity on the bicycle ergometer and positive correlation on the treadmill.     

多杀菌素Natular G30对海南省不同生境致倦库蚊的控制效果比较研究

目的 比较不同剂量多杀菌素Natular G30在生活污水与小型净水中对致倦库蚊海口种群的控制效果,为其在蚊虫控制中的应用提供依据.方法 用海南省海口市生活污水与小型净水中的致倦库蚊幼虫和水,在外环境以减退率为指标,分别测定Natular G30 10、20、40和80 mg/m2对蚊虫的控制效果.试验中,两次测量试验水体的水质pH值、温度、总固体含量、盐度、溶解氧含量.结果 生活污水的pH值、溶解氧含量分别为（9.62±0.43）、（12.79±3.01）mg/L,小型净水分别为（8.91±0.39）、（7.77±3.46）mg/L,二者差异有统计学意义（P＜0.05）.在生活污水中,多杀菌素有效浓度为10和20 mg/m2时,蚊虫控制持效时间为12d,40和80 mg/m2处理的则＞30 d;而在小型净水中,所有4个浓度均有超过30 d的持效期.两种水体所有剂量在第1天对1、2龄期幼虫的减退率即接近100％,3、4龄期幼虫在第3～7天出现100％减退,而蛹在第1天的减退率基本为负值.结论 多杀菌素Natular G30对致倦库蚊幼虫的控制效果具有高效、持久的特点;且对1、2龄幼虫的毒性高于对3、4龄幼虫的毒性,对蛹无明显的毒杀作用.因其在小型净水中的效果优于生活污水,使用时应根据水质调整剂量.