Reoperation rates and risk factors for revision 4 years after dynamic stabilization of the lumbar spine

Background Context

The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).

Boosting treatment stabilization in patients of amphetamine-type stimulant use disorder

BackgroundTo investigate boosting effects on treatment stabilization in the mandatory treatment modality for patients of amphetamine-type stimulant use disorder.MethodsThis is a retrospective follow-up study over a period from January 2013 to December 2018. We analyzed 425 patients of amphetamine-type stimulant use disorder under mandating treatments. Treatment stabilization for a given patient was defined once 4 negative urinalysis had been observed. We developed a dynamic monitoring model of boosting effects informed by the available data, specifically the number of negative urine samples required to reach stabilization, the sum of urinalyses done at the time when the given number of negative urine samples had been observed and who the patient was. To represent the simulated population, a Monte Carlo method was used to generate p-values from 1000 experiments conducted on a computer.ResultsIn the observed samples, the probability of 4 negative results in urinalysis from 4 outpatient visits was 75.5%. In comparison, the probability for achieving 4th negative results in urinalysis over 4 visits from negative binominal distribution was 57.3%, and from the computer simulation, 49.8%. The observed samples had significantly higher probability of achieving 4 negative results in urinalysis over 4 outpatient visits (p < 0.001).ConclusionsThe mandatory treatment modality boosted treatment stabilization for patients of amphetamine-type stimulant use disorder. The major benefit of using the monitoring model is the ability to monitor boosting effects of stabilization. Results supported the effectiveness of this mandatory treatment modality and can be implemented in deferred-prosecution based treatment modality.     

FEEDBACK CONTROL OF A HEAT DIFFUSION SYSTEM WITH TIME-DEPENDENT SPATIAL DOMAIN

The problem of controlling the temperature distribution in a solid cylinder whose length varies with time and with one end in contact with a constant temperature medium is considered. This problem is motivated from that of controlling the temperature and thermal gradient inside a crystal pulled from a melt by the Czochralski method. Boundary feedback controls are derived by considering the time rate of change of a cost functional involving the deviations of both the solid temperature and its gradient from their desired values. The derived feedback controls consist of spatially distributed proportional-plus-rate and lag compensators and a non-linear feedback control involving the temperature gradient at the cylinder surface and the velocity of the spatial domain boundary. The resulting feedback-controlled system has the property that the cost functional along any motion decreases monotonically to zero with time. A numerical scheme for solving the partial differential equation of the feedback-controlled system is proposed. Typical numerical results on the dynamic behaviour of the feedback-controlled system obtained by means of the proposed scheme are presented.     

Arthroscopic Shoulder Stabilization: Is There Ever a Need to Open?

Recent studies show comparable results of arthroscopic shoulder stabilization techniques compared with the gold standard open Bankart reconstruction. Great technical advances and ever-increasing surgeon experience have rendered pathology once deemed an indication for open surgery as treatable by arthroscopic means. With this movement toward a more universal application of all-arthroscopic techniques, we might consider the following question: Is there ever a need to open? To answer this question, we must first consider normal anatomy and then appreciate the contribution of deranged pathoanatomy to recurrent instability in each individual case. The surgeon must then determine whether this is best addressed via an arthroscopic or open technique. Arthroscopy, as compared with open stabilization procedures, holds the potential benefits of decreased morbidity rates, early functional rehabilitation, and improved range of motion. Despite potential advantages, arthroscopic stabilization is clearly contraindicated when a significant pathologic lesion contributing to recurrent instability cannot be adequately addressed as a result of the limitations of current techniques or instrumentation. On the basis of this principle, we believe that sizable glenohumeral bone defects remain the only absolute contraindication to an all-arthroscopic approach. Many complicating issues, such as attenuated capsule, humeral avulsion of the glenohumeral ligament lesions, cases of revision surgery, and collision or contact athletes, exist and warrant close attention. We prefer to think of these situations as “challenges” for which both arthroscopic and open surgery should be considered, rather than as true contraindications to arthroscopic shoulder stabilization. We are, by no means, advocating arthroscopic treatment in all cases of shoulder instability, because this would represent a gross oversimplification of the issues at hand. However, we do acknowledge that the steadfast contraindications to arthroscopic shoulder stabilization are decreasing every day.     

The role of mast cells and histamine in leukocyte-endothelium interactions in four rat strains

 The objective of the present study was to determine the role of mast cells and histamine in leukocyte-endothelium interactions in mesenteric venules of four rat strains: Brown Norway, Lewis, Sprague-Dawley and Wistar. Intravital microscopy showed that the mast cell stabilizer cromoglycate (5 mg/kg i.v. just before exteriorization of the mesentery) did not affect the baseline level and velocity of leukocyte rolling in any of the four strains. This finding is in agreement with the observation that cromoglycate pretreatment only slightly influenced mast cell degranulation in all strains except the Brown Norway. After mast cell stabilization, only in Sprague-Dawley did topical administration of histamine (10^–4 M) result in a significant increase in the level of leukocyte rolling and a decrease in the rolling velocity compared with the time control. Histamine induced leukocyte adhesion only in the Brown Norway strain. In conclusion, the hypothesis presented in other studies, that degranulation of mast cells, and more specifically the release of histamine, is of major importance for the induction of leukocyte-endothelium interactions in rat mesenteric venules is not generally applicable; the present study shows a clear strain dependency. Received: 18 July 1997 / Received after revision: 17 November 1997 / Accepted: 13 March 1998     

Voluntary head stabilization in space during oscillatory trunk movements in the frontal plane performed in weightlessness

 The ability voluntarily to stabilize the head in space during lateral rhythmic oscillations (0.59±0.09 Hz) of the trunk has been investigated during microgravity (μG) and normal gravity (nG) conditions (parabolic flights). Five healthy young subjects, who gave informed consent, were examined. The movements were performed with eyes open or eyes closed, during phases of either μG or nG. The main result was that head orientation with respect to vertical may be stabilized about the roll axis under μG with, as well as without vision, despite the reduction in vestibular afferent and muscle proprioceptive inputs. Moreover, the absence of head stabilization about the yaw axis confirms that the degrees of freedom of the neck can be independently controlled, as was previously reported. These results seem to indicate that voluntary head stabilization does not depend crucially upon static vestibular afferents. Head stabilization in space may in fact be organized on the basis of either dynamic vestibular afferents or a short-term memorized postural body schema. Received: 4 October 1995 / Accepted: 30 September 1996     

微创内固定系统治疗复杂股骨转子部骨折的初步报告

目的探讨微创内固定系统(LISS)治疗复杂股骨转子部骨折的可行性、手术技术及指征,并总结其近期临床治疗效果。方法自2005年6月～2006年5月,应用LISS治疗复杂股骨转子部骨折12例。骨折采用AO分类法,其中转子间骨折5例：31-A2．2型2例,31-A2．3型2例,31-A3．3型1例；转子下骨折7例：32-A3．1型1例,32-B1．1型3例,32-B2．1型1例,32-B3．1型2例。记录手术时间、术中出血量、术后住院时间,术后观察有无感染、下肢深静脉血栓、心肺疾患、应激性溃疡等并发症。术后1、2、3、6、12个月时常规随访。结果手术时间50～90 min,平均65 min；出血量50～400 mL,平均142 mL,术后住院时间6～15 d,平均9．3 d。无死亡病例。所有患者均未出现切口感染、下肢深静脉血栓、术后心肺疾患、应激性溃疡等并发症。12例均获得3～14个月(平均7．2个月)随访。10例在术后3个月复查骨折时达到临床愈合,1例假体周围骨折术后4个月、1例病理性骨折术后6个月达到临床愈合。所有患者在最后一次随访时均无骨折再移位、髋内翻畸形、内固定切出、内固定失败及股骨头坏死。结论微创反向使用股骨LISS从生物力学和解剖结构上都能满足股骨近端骨折内固定要求,并具有创伤小、操作简便、固定可靠、安全性高、并发症少的特点,尤其适用于老年人合并内科疾病、骨质疏松较重的转子间骨折及复杂的股骨近端骨折。熟练掌握间接复位技术,正确放置A孔导针,避免过早负重是手术成功的关键。     

LISS钢板治疗股骨远端粉碎骨折的疗效分析

目的探讨应用微创固定系统LISS钢板治疗股骨远端粉碎骨折的临床疗效。方法采用LISS钢板治疗股骨远端粉碎骨折26例。结果所有患者获得10—28个月随访，切口Ⅰ期甲类愈合，骨折全部愈合，X线复查骨折对位、对线良好，未发生感染，无内固定钢板、螺钉脱出、断裂等发生。疗效评价采用Kolmert评定标准：优A3型10例，C2型3例；良A3型2例，C2型1例，C3型5例：可C2型2例，C3型2例；差C3型1例。结论采用微刨固定系统LISS钢板治疗股骨远端粉碎骨折，是一种有效的内固定方法，具有操作简便、创伤小、疗效肯定等优点，为术后早期功能锻炼提供保证。     

Responses of Neurons of the Nucleus of the Optic Tract and the Dorsal Terminal Nucleus of the Accessory Optic Tract in the Awake Monkey

The nucleus of the optic tract (NOT) and the dorsal terminal nucleus of the accessory optic tract (DTN) are essential nuclei for the generation of slow-phase eye movements during horizontal optokinetic nystagmus. We recorded from 101 neurons (all directionally selective) in four NOT/DTN of three trained and behaving rhesus monkeys. Neuronal activity increased when stimuli moved ipsiversively with respect to the recording site and decreased below spontaneous activity when stimuli moved contraversively. While the monkey fixated a small spot, some NOT/DTN neurons did not respond at all to the retinal image slip of a whole-field random dot pattern; others showed a monotonic increase of activity to increasing velocities of that stimulus. The velocity range tested was up to 100°/s. During the execution of optokinetic nystagmus, 39 of 73 cells tested showed a velocity-tuned response with an average optimum at 21°/s retinal image slip. Following saccades during optokinetic nystagmus (quick phases), the NOT/DTN neuronal activity briefly attained the level of spontaneous activity, as predicted from the velocity selectivity during optokinetic nystagmus. Immediately upon cessation of optokinetic stimulation in the preferred direction, NOT/DTN activity returned to the spontaneous level and did not reflect the ongoing optokinetic afternystagmus in darkness. Most NOT/DTN neurons displayed direction selectivity also during smooth pursuit. Twenty-one of 50 cells tested (42%) always responded to the retinal slip of the target (target velocity cells), 16 cells (32%) responded to the retinal slip of the background (background velocity cells), and 13 cells (26%) did not respond at all during smooth pursuit. We conclude from our results that the NOT/DTN is an essential structure for the processing of the direction and speed of retinal image slip. This information is then used for the generation and maintenance of slow eye movements, preferentially during horizontal optokinetic nystagmus but also during pursuit eye movements.     

侧块钢板螺钉系统在颈椎后路手术中的应用

目的 探讨侧块钢板螺钉系统在颈椎后路手术中应用的临床经验。方法 对1999年2月－2000年3月间共36例行侧块钢板内固定的患者进行回顾分析。29例（80．6％）获得随访,平均随访时间8个月（4－15个月）。29例患者中颈椎病（3节及3节段以上椎间盘突出）20例,黄韧带骨化症（OYL）1例,后纵韧带骨化症（OPLL）2例,颈椎骨折脱位6例。手术时采取坐位,病变节段行全椎板切除减压,保留关节突。钢板螺钉固定于侧块（即关节突）,同时关节突间植骨融合。结果 29例患者共植入124枚螺钉,平均每位患者4．3枚。颈痛明显改善者为18例（20例术前存在颈痛）占90％。术后3－6月X线随访,27例患者关节突间见骨小梁生成,融合率93％。4例患者路侧块钢板螺钉系统能提供较稳定的固定,有效改善颈痛。钢板螺钉松动与神经根损伤是较严重的并发症。只要严格掌握手术适应证与安装技术,颈椎后路钢板固定是治疗颈椎不稳的一种十分有效的方法。