胫骨高位截骨术治疗膝内翻伴膝外摆步态的疗效与不足

[目的]探讨外侧闭合胫骨高位截骨术治疗膝内翻伴膝外摆步态患者的临床效果及相关的影响因素。[方法]随访2000~2004年因膝内翻伴膝外摆步态于本院行胫骨高位截骨手术的患者19例,年龄47~54岁,随访时间6个月~4 a。术前及术后X线片测量股骨-胫骨角、胫骨平台后倾角和腓骨小头高度,HSS膝关节功能评分,关节后外侧稳定性测试,术后患者以五点问卷法评价术后关节稳定性的改善情况。[结果]股骨-胫骨角术前184.5°~197°,术后167°~176°;腓骨小头高度术前7.73~18.5 mm,术后-3.5~10.7 mm;胫骨后倾角术前2°~17°,术后-4°~13°;HSS评分术前48~68分,术后60~91分(P=0.00)。后外侧的稳定性测量术前Ⅰ度损伤16例,Ⅱ度损伤3例。术后Ⅰ度损伤9例,Ⅱ度损伤10例(P<0.05)。术后患者关节稳定性的问卷4例明显提高,9例有提高,6例与术前相同。[结论]外侧闭合胫骨高位截骨治疗膝内翻合并膝外摆的近期效果良好,远期效果可能受到膝外摆步态、胫骨后倾角和腓骨小头高度改变的影响。     

单枚椎间融合器短节段椎弓根螺钉内固定治疗腰椎失稳症

目的:评价单枚椎问融合器植骨融合短节段椎弓根螺钉内固定治疗腰椎失稳症的临床疗效.方法:1999年3月～2007年8月我院采用单枚椎间融合器植骨融合结合短节段椎弓根螺钉内固定治疗腰椎失稳症患者中资料完整的病例149例,男83例,女66例,年龄32～68岁,平均46.7岁.失稳节段:L3/4 7例,L4/5 50例,L5/S1 92例.采用NaKai评定标准判定术后疗效,观察术后失稳椎体间有无移位,椎弓根螺钉及椎间融合器位置情况;测量术前、术后1周、术后16个月失稳椎间隙高度与上位椎间隙高度的比值.结果:手术时间1.5～3h,平均1.8h;术中出血量200～600ml,平均490ml.并发硬膜囊撕裂5例,神经根牵拉伤4例.随访16个月～6年9个月,平均39个月,术后腰椎序列恢复正常;术后1周失稳椎间隙高度与上位椎间隙高度的比值与术前比较有统计学差异(P.0.05);术后16个月时按NaKai标准评定,优115例,良26例,可8例,优良率94.5%;术后16个月时,按Suk标准评定椎间融合率为100%;末次随访时无失稳复发,椎弓根螺钉及椎间融合器均无松动、移位等.结论:单枚椎间融合器植骨融合短节段椎弓根螺钉内固定是治疗腰椎失稳症比较可靠的方法,能很好地维持椎间隙的高度和节段的稳定.     

A technique for frameless stereotaxy and placement of transarticular screws for atlanto-axial instability in rheumatoid arthritis

The aim of the present study was to outline a new surgical technique and describe how, in a clinical setting, computer-generated image-guidance can assist in the planning and accurate placement of transarticular C1/C2 screws inserted using a minimally invasive exposure. Forty-six patients with atlanto-axial instability due to rheumatoid arthritis underwent posterior stabilisation with transarticular screws. This was achieved with a minimal posterior exposure limited to C1 and C2 and percutaneous screw insertions via minor stab incisions. The Stealth Station (Medtronic Sofamor Danek, Memphis, Tenn., USA) was used for image guidance to navigate safely through C2. Reconstructed computed tomographic (CT) scans of the atlanto-axial complex were used for image guidance. It was possible to perform preoperative planning of the screw trajectory taking into account the position of the intraosseous portion of the vertebral arteries, the size of the pars interarticularis and the quality of bone in C2. Screws could be inserted percutaneously over K-wires using a drill guide linked to the image-guidance system. Preoperative planning was performed in all 46 patients and accurate registration allowed proposed screw trajectories to be identified. Thirty-eight patients had bilateral screws inserted and eight had a unilateral screw. A total of 84 screws were inserted using the Stealth Station. There were no neurovascular injuries. This technique for placing transarticular screws is accurate and safe. It allows a minimally invasive approach to be followed. Image guidance is a useful adjunct for the surgeon undertaking complex spinal procedures.     

部分切除腓骨对踝关节稳定的影响

对8例新鲜尸体的踝关节在完整胫腓骨与腓骨部分切除时的外踝上下和侧向位移变化进行了测试与分析,结果显示腓骨部分切除后,外踝无论是上下位移还是侧向位移都显著增加,表明完整的腓骨对维持踝关节的稳定具有相当大作用。     

Predictors of early and late instability following conservative treatment of extra-articular distal radius fractures

Introduction The purpose of this study was to identify radiological predictors of early and late instability following conservative treatment of extra-articular distal radius fractures.Materials and methods An observational study design was employed using patient records and standardized radiological follow-up examinations as data sources. The database at a single institution was used to identify all patients with extra-articular distal radius fractures over the course of 1 year. A total of 71 patients with extra-articular distal radius fractures (50 dorsally displaced, 21 undisplaced) fulfilled the inclusion criteria. Patients were predominantly female (87%) with a pooled mean age of 64.9 years. All patients with displaced extra-articular distal radius fractures underwent closed reduction with subsequent cast immobilization. Undisplaced fractures were simply treated with cast immobilization. The primary outcomes were early (1 week) and late (6 weeks) instability of the fracture. Instability was defined as: (1) dorsal tilt >15°, (2) volar tilt >20°, (3) ulnar variance >4 mm, (4) radial inclination <10°.Results Degree of radial shortening and volar tilt were predictive of early instability (p<0.05), with dorsal comminution also approaching statistical significance (p=0.06). Radial inclination, age, radial shortening, and volar tilt were predictive of late failure (p<0.05). An unexpected result showed that one-third of undisplaced fractures went on to fail, most of which occurred in those patients over the age of 65 years.Conclusion An awareness of independent predictors of instability in extra-articular distal radius fractures is helpful in anticipating the final alignment outcome.     

Mechanical behavior and stability of the internal membrane of the InCor ventricular assist device

Abstract: This paper describes and analyzes the mechanical behavior of the internal membrane of the InCor VAD (Heart Institute [InCor], University of São Paulo, Brazil), applying the knowledge and tools of structural engineering analysis. This membrane plays an important role in the operation of the ventricular assist device (VAD) because it separates the blood chamber from the pneumatic one, transmitting the pneumatic load to the blood, thus making the desired blood flow possible. The loading repeats itself every time the VAD beats. Therefore the performance, reliability, and durability of the membrane are critical for the performance of the VAD. The mathematical model is based on the large deflection theory of thin shells and on the finite element method. The snap‐through instability phenomenon, which is responsible for transmission of the pneumatic load to the blood, was observed in the membrane both when modeled mathematically and experimentally. Principal stresses and strain distributions were obtained with this model at certain load levels along the pre‐ and postbuckling paths.     

Hunting for robust gene signature from cancer profiling data: Sources of variability,different interpretations,and recent methodological developments

Gene microarray is a powerful platform to investigate the expression patterns of thousands of genes simultaneously. One central objective of such analysis is to select sets of genes (i.e., gene signatures) which correlate with clinical characteristics, such as disease subtype diagnosis, response to drug treatment and prognosis. However, previous studies have found that mRNA signatures are highly unstable and strongly depend on the selection of patient samples. Based on five large microRNA profiling datasets, we empirically found that microRNA signatures are also generally unstable. Therefore, concerns arise regarding the reproducibility and clinical applicability of these derived gene signatures. Here, we first provide a brief review on the sources of variability and different interpretations of multiple distinct gene signatures. We then focus on those recent methodological progresses aimed at developing more stable gene signatures.     

Coracoid transfer in Bristow–Latarjet procedure: does it modify the biceps muscle?

The aim of this study is to evaluate the size and morphologic patterns of the biceps muscle after coracoid transfer performed during the Bristow–Latarjet procedure to treat anterior shoulder instability. We analyzed retrospectively 26 patients, who underwent a Bristow–Latarjet procedure, and 23 volunteers (control group) with no shoulder disease. A US machine (ATL 5000 HDI, probe 4.2 MHz) was used to determine the biceps section area (BA) and biceps echogenicity (BE). The dominant and non-dominant limbs in both groups were compared. The coracoid transfer performed in the Bristow–Latarjet procedure to treat recurrent anterior shoulder instability does not modify the size and morphology of the biceps muscle.