MSCT扫描重建健侧胫骨在患侧内固定材料塑形中的意义

[目的]探索一种内固定材料塑形新方法。[方法]扫描并三维重建健侧胫骨，在健侧测量患侧拟行L形钢板固定的横、纵曲线形状及各长度参数，然后利用曲线描绘工具等比例绘出2曲线。最后以2曲线为基础对L形钢板塑形。[结果]准确测量出了2曲线的形状及各长度参数，并等比例绘出了健侧2曲线，最后成功对钢板进行了塑形。[结论]该方法完全能等比例绘出拟行内固定的曲线，并对钢板进行塑形，可显著提高内固定物与胫骨表面的贴附率，缩短手术时间，提高手术疗效。部分病例健侧骨质增生可能影响塑形精度，但通过健侧仍可将内置板材塑出基本形状，术中稍微修改即可。     

Ulnar variance and the shape of the lunate bone. A radiological investigation

The authors designed a study to test the hypothesis that the length of the ulna might affect the shape of the lunate bone because of long-term molding during life. This might then be useful to predict the presence or absence of a dynamic or static ulna plus by the shape of the lunate bone. In a prospective study, posterior-anterior wrist x-rays were taken in a standard fashion in 68 patients with a mean age of 34.5 years. Dominance, grip strength, ulnar variance and the shape of the lunate were recorded. Lunate shape, type 1, which is the least molded, was seen most frequently on both the left and right side and did not correlate with the dominant side. The most molded, type 3, was seen less frequently and almost exclusively on the nondominant side. No correlation was found between dynamic ulna plus and the type 3 lunate. Following statistical analysis, no correlation between ulnar variance and lunate shape was found, indicating that the shape of the lunate bone had no predictive value for predicting the presence or absence of a dynamic ulna plus variance. The hypothesis that the length of the ulna might influence the ultimate shape of the lunate could not be demonstrated.     

Beyond fusiform and saccular: a novel quantitative tortuosity index may help classify aneurysm shape and predict aneurysm rupture potential

While saccular abdominal aortic aneurysms (AAAs) are thought to be more prone to rupture than fusiform aneurysms, attempts to validate this observation have been limited by the inability to quantitatively define the three-dimensional shape of an aorta. A quantitative three-dimensional shape model may distinguish among shape classes and ultimately be useful in identifying aneurysms at risk for rupture. Three-dimensional luminal surface data of AAAs were generated from computed tomographic (CT) images of 15 patients with small aneurysms (< or =5.5 cm maximal transverse diameter). The centerline was used to construct a shape classification based upon the orthographic projection of the centerline about its central axis. The extent and direction of the individual deviations were quantified as areas on the plane of projection to create a shape classification. Hierarchical cluster analysis was used to verify distinct shape classes. A tortuosity index was calculated as a function of the centerline projection. AAA shape was calculated as a tortuosity index and classified into distinct classes of minimal or increased three-dimensional tortuosity. Thrombus could change the tortuosity index or shape classification of an aneurysm. In several patients with serial CT scans, the tortuosity index changed over time and was correlated with rupture; in three AAAs that ruptured the mean tortuosity increased 29% whereas the mean transverse diameter increased 3.3%. Expanding AAAs develop specific, quantifiable shapes that can be expressed as a quantitative tortuosity index that may be relevant to their natural history. The three-dimensional features of this shape model provide a novel and potentially clinically relevant adjunct to maximal transverse diameter. Larger studies are needed to correlate the tortuosity index with finite element models and the ability to predict aneurysm rupture.     

Assessment of pedicle screw pullout strength based on various screw designs and bone densities—an ex vivo biomechanical study

Background contextThe pedicle screw fixation system has been used for various spinal disorders. Many studies have been conducted on the fixation ability of the pedicle screw, but variable results have been reported based on bone qualities, pedicle screw properties, insertion techniques, and experimental methods.Study designAn experimental and biomechanical study.PurposeTo evaluate the geometric factors of screws affecting fixation ability after assessing pullout strength based on various pedicle screw designs and different bone densities.MethodsNine types of pedicle screws were prepared according to the outer diameter shape (cylindrical or conical), the inner diameter shape (cylindrical or conical), and thread shape (V shape, buttress shape, and square shape). The pedicle screws were inserted into standardized polyurethane foams of Grades 5, 15, and 20. The pullout strength of each pedicle screw was determined using an MTS 858 machine (Material Testing System Corp., Minneapolis, MN, USA), and the results were analyzed statistically.ResultsPullout strength based on the shape of thread was the highest in the V shape and lowest in the square shape for all foam grades (p<.05). The outer cylindrical and inner conical shape of pedicle screw showed the highest pullout strength in Grades 5 and 15 foam (p<.05). An outer cylindrical and inner conical shape with a V-shaped thread showed the highest pullout strength in all foam grades (p<.05).ConclusionsPedicle screw with an outer cylindrical and inner conical configuration with a V-shaped thread may have maximum pullout strength, regardless of bone density.     

Mirror形体设计软件在下颌骨整形中的应用

目的:探索Mirror形体设计软件在下颌骨整形的应用优势。方法:将95例面部轮廓整形的患者随机分为设计组和对照组两组,应用Mirror形体设计软件对设计组患者进行术前形态分析设计、模拟术后形态,并对比测量出改变数据,对照组患者直接进行手术而不使用Mirror形体设计软件,对比两组患者术后医患满意率的差别。结果:应用Mirror形体设计软件进行术前分析设计的设计组患者,其医患满意率大于未使用设计软件的对照组患者,差别有统计学意义。结论:通过应用Mirror形体设计软件能很好的对患者形态进行测量分析,并模拟出术后形态,达到医患理想要求,并通过改变数据来指导手术进行,本系统能够加强医患之间的交流,对容貌进行定量分析诊断,使整形手术更加精准完美。     

The effect of regional ischemia on mitral valve annular saddle shape

BACKGROUND: The mitral valve annulus has a distinctive saddle shape. Recent finite element analysis indicates this shape may contribute to normal valve function by increasing leaflet curvature and reducing leaflet stress. This study tests the hypothesis that acute ischemic mitral regurgitation (AIMR) is associated with loss of annular saddle shape. METHODS: Sonomicrometry array localization (SAL) measured the three-dimensional geometry of the mitral annulus in 6 sheep before and after 30 min of posterior ischemia that produced severe AIMR. Using this SAL data the annular height to commissural width ratio (AHCWR), a measure of annular saddle shape, was calculated throughout the cardiac cycle and reported as a percentage. RESULTS: The normal mitral annulus accentuated its saddle shape rapidly during isovolemic contraction: AHCWR increased from 11.6% +/- 1.1%-13.9% +/- 1.6% (p < 0.001). During ejection AHCWR remained relatively constant ranging from a minimum of 14.1% +/- 1.5% to a maximum of 14.9% +/- 1.3%. During ischemia AHCWR was found to be significantly smaller (p < 0.05) during isovolemic contraction, ejection, and isovolemic relaxation, but not during diastolic filling. Whereas ischemia did not affect AHCWR at end diastole (11.6% +/- 2.8%), the isovolemic accentuation of the saddle shape was lost. CONCLUSIONS: The normal mitral annulus accentuates its saddle shape during systole. This accentuation is eliminated during ischemia that causes AIMR. These data suggest an association between annular saddle shape and valve competency.     

Shape is only a weak predictor of deep knee flexion kinematics in healthy and osteoarthritic knees

Tibiofemoral shape influences knee kinematics but little is known about the effect of shape on deep knee flexion kinematics. The aim of this study was to examine the association between tibiofemoral joint shape and kinematics during deep kneeling in patients with and without osteoarthritis (OA). Sixty-one healthy participants and 58 patients with end-stage knee OA received a computed tomography (CT) of their knee. Participants completed full flexion kneeling while being imaged using single-plane fluoroscopy. Six-degree-of-freedom kinematics were measured by registering a three-dimensional (3D)-static CT onto 2D-dynamic fluoroscopic images. Statistical shape modeling and bivariate functional principal component analysis (bfPCA) were used to describe variability in knee shape and kinematics, respectively. Random-forest-regression models were created to test the ability of shape to predict kinematics controlling for body mass index, sex, and group. The first seven modes of the shape model up to three modes of the bfPCAs captured more than 90% of the variation. The ability of the random forest models to predict kinematics from shape was low, with no more than 50% of the variation being explained in any model. Furthermore, prediction errors were high, ranging between 24.2% and 29.4% of the data. Variations in the bony morphology of the tibiofemoral joint were weakly associated with the kinematics of deep knee flexion. The models only explained a small amount of variation in the data with high error rates indicating that additional predictors need to be identified. These results contribute to the clinical understanding of knee kinematics and potentially the expectations placed on high-flexion total knee replacement design.     

The lateral fold mammaplasty

The mammaplasty is characterized by the non-reliability of the shape achieved at the end of the operation: sometimes a conic shape is expected and a relatively flat breast is obtained. The mammaplasty is also characterized by the lateral slipping of the shape with time, cause of the sad aspect of the breast. The purpose of the lateral fold mammaplasty is to facilitate the creation of the desired shape and to stabilize the evolution of this shape with time. The standard mammaplasty technique can determine the sub-mammary fold; the medial contour with its specific shape is already determined. Those inferior and medial folds are stables. But the lateral contour is usually not defined and very rarely stable with time. This procedure creates a well-defined and stable lateral fold, which is the convex junction between the anterior axillary line and the sub-mammary fold. This new fold is designed by attachment with five sutures of the axillary sub-dermal tissues to the lateral border of the pectoralis major muscle and just beneath, to the 5th costal arch. A medial tension is applied to the axillary flap before suturing to improve the axillary region. Consequently, the breast shape is more predictable and more stable because the lateral, inferior and medial folds are definitely determined. The realization is simple with no specific complication. It could be an additional procedure to any mammaplasty technique.     

Quantified aneurysm shape and rupture risk

OBJECT: The authors investigated whether quantified shape or size indices could better discriminate between ruptured and unruptured aneurysms. METHODS: Several custom algorithms were created to quantifiy the size and shape indices of intracranial aneurysms by using three-dimensional computerized tomography angiography models of the brain vasculature. Data from 27 patients with ruptured or unruptured aneurysms were evaluated in a blinded fashion to determine whether aneurysm size or shape better discriminated between the ruptured and unruptured groups. Five size and eight shape indices were calculated for each aneurysm. Two-tailed independent Student t-tests (significance p < 0.05) were used to determine statistically significant differences between ruptured and unruptured aneurysm groups for all 13 indices. Receiver-operating characteristic-area under curve analyses were performed for all indices to quantify the predictability of each index and to identify optimal threshold values. None of the five size indices were significantly different between the ruptured and unruptured aneurysms. Five of the eight shape indices were significantly different between the two lesion groups, and two other shape indices showed a trend toward discriminating between ruptured and unruptured aneurysms, although these differences did not reach statistical significance. CONCLUSIONS: Quantified shape is more effective than size in discriminating between ruptured and unruptured aneurysms. Further investigation will determine whether quantified aneurysm shape will prove to be a reliable predictor of aneurysm rupture.     

镍钛形状记忆合金生物相容性的概况

镍钛(NiTi)形状记忆合金具有独特的形状记忆、超弹性、耐蚀性等理化性能,但是作为长期植入物,有学者对富含Ni原子的NiTi合金的生物安全性提出疑问。结合近年来的研究进展,本文旨在对NiTi合金的耐蚀性、Ni溶出、生物相容性及多孔NiTi的生物相容性进行综述。     

A comparative study of shape representation in macaque visual areas v2 and v4

We compared aspects of shape representation in extrastriate visual areas V2 and V4, which are both implicated in shape processing and belong to different hierarchical levels. We recorded responses of cells in awake, fixating monkeys to matched sets of contour and grating stimuli of low or intermediate complexity. These included simple stimuli (bars and sinusoids) and more complex stimuli (angles, intersections, arcs, and non-Cartesian gratings), all scaled to receptive field size. The responses of cells within each area were substantially modulated by each shape characteristic tested, with substantial overlap between areas by many response measures. Our analyses revealed many clear and reliable differences between areas in terms of the effectiveness of, and response modulation by, various shape characteristics. Grating stimuli were on average more effective than contour stimuli in V2 and V4, but the difference was more pronounced in V4. As a population, V4 showed greater response modulation by some shape characteristics (including simple shape characteristics) and V2 showed greater response modulation by many others (including complex shape characteristics). Recordings from area V1 demonstrated complex shape selectivity in some cells and relatively modest population differences in comparison with V2. Altogether, the representation of 2-dimensional shape characteristics revealed by this analysis varies substantially among the 3 areas. But surprisingly, the differences revealed by our analyses, individually or collectively, do not parallel the stepwise organization of the anatomical hierarchy. Commonalities of visual shape representation across hierarchical levels may reflect the replication of neural circuits used in generating complex shape representations at multiple spatial scales.     

How many different types of femora are there in primary hip osteoarthritis? An active shape modeling study

We assessed the variation in proximal femoral canal shape and its association with geometric and demographic parameters in primary hip OA. In a retrospective cohort study, the joint geometry of the proximal femur was evaluated on radiographs and corresponding CT scans of 345 consecutive patients with end‐stage hip OA. Active shape modeling (ASM) was performed to assess the variation in endosteal shape of the proximal femur. To identify natural groupings of patients, hierarchical cluster analysis of the shape modes was used. ASM identified 10 independent shape modes accounting for >96% of the variation in proximal femoral canal shape within the dataset. Cluster analysis revealed 10 specific shape clusters. Significant differences in geometric and demographic parameters between the clusters were observed. ASM and subsequent cluster analysis have the potential to identify specific morphological patterns of the proximal femur despite the variability in proximal femoral anatomy. The study identified patterns of proximal femoral canal shape in hip OA that allow a comprehensive classification of variation in shape and its association with joint geometry. Our data may improve future stem designs that will optimize stem fit and simultaneously allow individual restoration of hip biomechanics. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:413–422, 2014.     

膀胱全切原位W形回肠代膀胱术120例临床分析

目的 探讨膀胱全切原位W形回肠代膀胱术优缺点。方法120例男性膀胱癌患者,其中浸润性膀胱移行细胞癌99例,移行细胞癌伴部分鳞化8例,移行细胞癌伴腺癌及鳞癌3例,腺癌6例,鳞癌4例,均行膀胱全切原位W形回肠代膀胱术。膀胱全切采用顺行、逆行相结合的方法。截取末段回肠,排列成W形,褥式缝合制作储尿袋。输尿管以乳头法包埋术种植。结果手术时间,前50例为210-300mim,平均270min;后70例为110-205min,平均143min。术后9l例获得随访,随访2—88个月,平均30个月,85例白天可控制排尿,其中71例夜间可控制排尿。9例术后发生输尿管扩张,7例合并轻度肾积水,2例合并中度肾积水,2例肾功能轻度异常。45例行膀胱造影仅1例发生右侧输尿管返流。术后3个月复查出现低血钾者6例,余85例血电解质均在正常范围。20例患者行尿动力检查,尿流曲线呈持续型12例,间歇型8例;膀胱尿道造影显示尿流持续型代膀胱颈口呈漏斗形,排尿时开放良好,而尿流间歇形代膀胱颈口不呈漏斗形或排尿时颈口开放欠佳。结论膀胱全切原位W形回肠代膀胱术手术时间短,操作简单,出血少,并发症少,原位W形回肠代膀胱有较好的储尿和排尿功能,电解质紊乱发生率低。     

Alignment of trans-tibial prostheses based on roll-over shape principles

The authors examined the roll-over shape alignment hypothesis, which states that prosthetic feet are aligned by matching their roll-over shapes with an "ideal" shape. The "ideal" shape was considered to be the roll-over shape of the able-bodied foot-ankle system. An alignment algorithm and computational alignment system were developed to set trans-tibial alignments based on this hypothesis. Three prosthetic feet with considerably different roll-over shapes were either aligned using the alignment system or not aligned (i.e. used previous foot's alignment), and then were aligned by a team of prosthetists. No significant differences were found between roll-over shapes aligned by the computational alignment system and those based on standard clinical techniques (p = 0.944). Significant differences were found between the "no alignment" shapes and the prosthetist alignment shapes (p = 0.006), and between the "no alignment" shapes and the computational alignment system shapes (p = 0.024). The results of the experiment support the hypothesis that the goal of alignment is to match the prosthetic foot's roll-over shape, as closely as possible, with an "ideal" shape. The hypothesis is also supported by its ability to explain the results of previous studies. Using an "ideal" roll-over shape or surface as a goal for prosthetic alignment could lead to a priori alignment, eliminating the need for alignment hardware in some cases. Being able to build the alignment into a prosthesis without special hardware could be beneficial in low-income countries and in the fabrication of lightweight prostheses for the elderly.     

Decision Making in the Treatment of Tuberous and Tubular Breasts: Volume Adjustment as a Crucial Stage in the Surgical Strategy

Tuberous and tubular breasts, two distinct deformities based on the same anatomic anomaly, are characterized by several morphologic alterations with a wide spectrum of expression. The classifications reported in the literature are based primarily on deformity of shape, but other parameters such as breast volume and symmetry often are underrated. This study aimed to define tuberous and tubular breasts and their management accurately on the basis of multiple anatomic alterations involving breast volume and symmetry as well as shape. The records of 30 patients affected by tubular and tuberous breast were reviewed. Surgical strategy included correction of breast shape through areola and gland alterations, correction of volume asymmetry through parenchyma resection, and volume augmentation through permanent expandable breast implant insertion. All the patients were treated bilaterally. Evaluation using a visual analogic scale confirmed high patient satisfaction with a mean value of 92.6% in the assessment of shape, volume, and symmetry. Correct diagnosis, careful preoperative evaluation, and a comprehensive surgical strategy can achieve, in one surgical procedure, good and long-lasting outcomes in terms of breast shape and volume symmetry.     

双梭形切口在腺性唇炎美容手术中的应用

目的：探讨腺性唇炎的美容手术治疗方法。方法：在病变的上下唇分别采用非贯通双梭形切口，行病变组织切除。观察术后的唇红，唇珠、唇形的变化。结果：12例患者术后唇红丰满，唇珠明显，唇形自然。优良率100％。结论：双梭形切口是治疗腺性唇炎理想的手术方法。     

Simultaneous Scatterer Shape Estimation and Partial Aperture Far-Field Pattern Denoising

We study the inverse problem of recovering the scatterer shape from the far-field pattern(FFP) in the presence of noise. Furthermore, only a discrete partial aperture is usually known. This problem is ill-posed and is frequently addressed using regularization. Instead, we propose to use a direct approach denoising the FFP using a filtering technique. The effectiveness of the technique is studied on a scatterer with the shape of the ellipse with a tower. The forward scattering problem is solved using the finite element method (FEM). The numerical FFP is additionally corrupted by Gaussian noise. The shape parameters are found based on a least-square error estimator. Ifũ_∞ is a perturbation of the FFP then we attempt to find Γ, the scatterer shape, which minimizes ‖ u_∞−ũ_∞‖ using the conjugate gradient method for the denoised FFP.     

Flexor tendon repair using shape memory alloy suture: a biomechanical evaluation

The purpose of the current study was to test in vitro a new shape memory alloy suture for flexor tendon repair. Forty fresh-frozen human anatomic flexor superficialis and profundus tendons were divided and repaired via the cruciate four-strand technique using one of two suture materials (the shape memory alloy suture and the 4-0 Ethibond suture). The forces required to cause a 1, 2, and 3 mm gap, ultimate load to failure, and repair stiffness were compared. Twenty specimens of each suture material also were tensile tested for load to failure, tensile strength, and elongation at failure. The shape memory alloy suture had a significantly higher mean resistance force to 1, 2, and 3 mm gap formation than the 4-0 Ethibond suture (47 N versus 31 N, 51 N versus 36 N, and 57 N versus 41 N, respectively). The shape memory alloy suture repair was 40% stronger than the 4-0 Ethibond suture (61.9 +/- 8.8 N versus 44.3 +/- 10.6 N). Repair with the shape memory alloy suture was significantly stiffer than repair with the 4-0 Ethibond suture (8.1 +/- 1.0 N/mm versus 6.1 +/- 0.9 N/mm). The load to failure and tensile strength of the shape memory alloy suture were significantly higher than that of the 4-0 Ethibond suture. The values of elongation for the two materials were not significantly different. The results of the current study suggest that the shape memory alloy suture may be superior to the 4-0 Ethibond suture in resisting gap formation in the range of forces generated in the early rehabilitation protocol and may be the future material of choice for tendon repairs.     

耳屏软骨在鼻尖和鼻小柱整形中的应用

目的:探讨鼻尖和鼻小柱整形中双侧耳屏软骨的应用。方法:切取双侧耳屏软骨,将一侧软骨沿长轴从中央不全层切开,翻转重叠形成Y形支撑杆,将另一块耳屏软骨盖在Y形杆上方,行成伞状软骨冒。飞鸟形切口切开鼻翼及鼻小柱,根据情况在鼻小柱下方可设计成V-Y切口。植入已做好的伞状软骨架,如鼻梁较低可同时植入假体隆鼻。结果:27例患者鼻尖均得到抬高,鼻小柱均有不同程度的延长。耳屏切口隐蔽,外形无明显改变,满意率达100%。结论:采用双侧耳屏软骨鼻尖成形,具有形象逼真,效果好,取材简单等特点,是鼻尖整形较好的软骨供体。