腰椎棘突间记忆合金动态稳定装置理论验证

为了在腰椎退变性疾病保守治疗和融合手术中间地带寻找一种有效的预防与辅助相结合的微创治疗方式,通过对比目前常用的几种腰椎棘突间动态稳定系统的临床疗效观察和优缺点,以及对腰椎棘突间的生理结构、生物力学和相关数据的分析,在充分了解记忆合金材质的基础上,自行设计研究一种记忆合金材料的新型腰椎棘突间动态固定装置,既能重建腰椎的正常生物力学特性,满足人体脊柱的正常活动,又避免对原有结构的破坏,减少术后并发症的发生,同时也可以优化目前的治疗方法。通过研究,腰椎棘突间记忆合金动态稳定装置在理论上效果满意,可以解决现有技术的不足,优于目前的几种腰椎棘突间动态稳定系统。     

Compressive Properties and Energy Absorption Characteristics of Extruded Mg-Al-Ca-Mn Alloy at Various High Strain Rates

This paper is focused on the mechanical properties and the energy absorption characteristics of the extruded Mg-Al-Ca-Mn alloy in different compression directions under high strain rate compression. Compressive characterization of the alloy was conducted from the high strain rate (HSR) test by using a Split Hopkinson Pressure Bar (SHPB). Results show that the investigated alloy exhibits a strong strain rate sensitivity. With the rise of strain rate, the compressive strength is increased significantly, and the deformation ability also improves. When compressed along the extrusion direction, as the strain rate increases, the total absorbed energy E, the crush force efficiency (CFE), and the specific energy absorption SEA of Mg-Al-Ca-Mn alloy are all greatly improved as compared with those obtained along other compression directions.     

Osseointegration of porous titanium and tantalum implants in ovariectomized rabbits: A biomechanical study

BACKGROUNDToday, biological fixation of uncemented press-fit acetabular components plays an important role in total hip arthroplasty. Long-term stable fixation of these implants depends on the osseointegration of the acetabular cup bone tissue into the acetabular cup implant, and their ability to withstand functional loads.AIMTo compare the strength of bone-implant osseointegration of four types of porous metal implants in normal and osteoporotic bone in rabbits.METHODSThe study was performed in 50 female California rabbits divided into non-ovariectomized (non-OVX) and ovariectomized groups (OVX) at 6 mo of age. Rabbits were sacrificed 8 wk after the implantation of four biomaterials [TTM, CONCELOC, Zimmer Biomet''s Trabecular Metal (TANTALUM), and ATLANT] in a 5-mm diameter defect created in the left femur. A biomechanical evaluation of the femur was carried out by testing implant breakout force. The force was gradually increased until complete detachment of the implant from the bone occurred.RESULTSThe breakout force needed for implant detachment was significantly higher in the non-OVX group, compared with the OVX group for all implants (TANTALUM, 194.7 ± 6.1 N vs 181.3 ± 2.8 N; P = 0.005; CONCELOC, 190.8 ± 3.6 N vs 180.9 ± 6.6 N; P = 0.019; TTM, 186.3 ± 1.8 N vs 172.0 N ± 11.0 N; P = 0.043; and ATLANT, 104.9 ± 7.0 N vs 78.9 N ± 4.5 N; P = 0.001). In the OVX group, The breakout forces in TANTALUM, TTM, and CONCELOC did not differ significantly (P = 0.066). The breakout force for ATLANT in the OVX group was lower by a factor of 2.3 compared with TANTALUM and CONCELOC, and by 2.2 compared with TTM (P = 0.001). In the non-OVX group, the breakout force for ATLANT was significantly different from all other implants, with a reduction in fixation strength by a factor of 1.9 (P = 0.001).CONCLUSIONTANTALUM, TTM, and CONCELOC had equal bone-implant osseointegration in healthy and in osteoporotic bone. ATLANT had significantly decreased osseointegration (P = 0.001) in healthy and in osteoporotic bone.     

Influence of Fine Grains on the Bending Fatigue Behavior of Two Implant Titanium Alloys

By means of the ultrasonic surface impact (amplitude of 30 μm, strike number of 48,000 times/mm²), nanograins have been achieved in the surfaces of both Ti6Al4V(TC4) and Ti3Zr2Sn3Mo25Nb(TLM) titanium alloys, mainly because of the dislocation motion. Many mechanical properties are improved, such as hardness, residual stress, and roughness. The rotating–bending fatigue limits of TC4 and TLM subjected to ultrasonic impact are improved by 13.1% and 23.7%, separately. Because of the bending fatigue behavior, which is sensitive to the surface condition, cracks usually initiate from the surface defects under high stress amplitude. By means of an ultrasonic impact tip with the size of 8 mm, most of the inner cracks present at the zone with a depth range of 100~250 μm in the high life region. The inner crack core to TC4 usually appears as a deformed long and narrow α-phase, while the cracks in TLM specimens prefer to initiate at the triple grain boundary junctions. This zone crosses the grain refined layer and the deformed coarse grain layer. With the gradient change of elastic parameters, the model shows an increase of normal stress at this zone. Combined with the loss of plasticity and toughness, it is easy to understand these fatigue behaviors.     

可吸收棒或钛合金螺钉治疗MasonⅡ型桡骨头骨折的疗效

文题释义：可吸收棒、钛合金螺钉内固定：两者均属于MasonⅡ型桡骨头骨折螺钉内固定法，主要区别在于其制作材质不一样，前者是由聚乳酸制成的可吸收高分子聚合物，而后者为钛合金制成，需二次手术取出。桡骨头骨折Mason分类：Ⅰ型，为线状骨折，即无移位型骨折，骨折线可通过桡骨头边缘或呈劈裂状；Ⅱ型，为有移位的骨折，有分离的边缘骨折；Ⅲ型，为粉碎型骨折，移位或无移位或呈塌陷性骨折；Ⅳ型，为桡骨头骨折伴有肘关节脱位。 背景：目前切开复位内固定是治疗MasonⅡ型桡骨头骨折的有效方法，内固定的选择有螺钉、微型钢板、克氏针、可吸收棒或钉等，临床疗效报道不一致。 目的：对比可吸收棒或钛合金螺钉内固定治疗MasonⅡ型桡骨头骨折的临床疗效。方法：选择2016年1月至2017年2月四川省人民医院收治的桡骨头骨折患者25例，其中男16例，女9例，年龄38-61岁，均进行切开复位内固定治疗，其中13例的内固定材料为钛合金螺钉，另12例的内固定材料为可吸收棒。术后随访拍摄X射线片，确定骨折愈合时间。末次随访时，对比两组目测类比评分、肘关节活动度及肘关节功能Mayo评分与Broberg-Morrey 评分。该研究已通过四川省医学科学院·四川省人民医院伦理委员会的审批。结果与结论：①可吸收棒组、钛合金螺钉组的骨折愈合时间分别为(2.35±0.92)，(2.10±0.47)个月，组间比较差异无显著性意义(P > 0.05)；②末次随访时，两组间肘关节功能Mayo评分与Broberg-Morrey 评分比较差异均无显著性意义(P > 0.05)；③末次随访时，两组间肘关节屈曲、伸直、旋后、旋前角度比较差异均无显著性意义(P > 0.05)；④末次随访时，两组目测类比评分比较差异均无显著性意义(P > 0.05)；⑤结果表明，可吸收棒与钛合金螺钉治疗MasonⅡ型桡骨头骨折的临床疗效相似，但可吸收棒避免了二次手术取出内固定及应力性遮挡等情况。 ORCID: 0000-0003-4778-7050(杨晓) 中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程     

颈前路减压零切迹椎间融合器与传统钛板固定融合术后相邻节段退变的比较

目的 :比较颈前路减压零切迹椎间融合器(Zero-P)与传统钛板内固定融合术治疗单/双节段脊髓型颈椎病对术后相邻节段退变的影响。方法:回顾性分析2015年1月～2018年3月采用颈前路减压Zero-P与传统钛板内固定融合术治疗的113例脊髓型颈椎病患者的资料,其中Zero-P组(A组)65例,传统钛板组(B组)48例,A组再分为单节段组(n=44)和双节段组(n=21),B组再分为单节段组(n=28)和双节段组(n=20),4组患者年龄、性别构成比、手术节段均无统计学差异(P0.05)。比较两种术式的手术时间、术中出血量,以及4组的术前、末次随访时的日本骨科协会(Japanese Orthopaedie Association,JOA)评分、疼痛视觉模拟评分(visual analog scale,VAS),末次随访时评估患者术后是否出现吞咽困难,并在颈椎侧位X线片上测量术前、术后即刻、末次随访时相邻节段椎间隙高度,评估术前、末次随访时的相邻椎体骨化情况,在颈椎MRI上应用椎间盘Pfirrmann分级评估术前、末次随访时的相邻节段椎间盘退变情况。结果:单节段A组随访时间为18.0±7.9个月,单节段B组为15.8±8.8个月,双节段A组为14.8±6.4个月,双节段B组为15.8±8.2个月,4组间无统计学差异(P0.05)。A组手术时间较B组明显缩短(P0.05),术中出血量两组无明显差异(P0.05)。4组患者末次随访时的JOA评分、VAS评分较术前均有明显改善(P0.05),同节段A、B组间比较JOA评分改善率无明显差异(P0.05),术前、末次随访时同节段A、B组间比较VAS评分无明显差异(P0.05)。双节段B组末次随访时上、下相邻椎间隙高度较术前、术后均有明显下降(P0.05),其余3组末次随访时上、下相邻椎间隙高度较术前、术后均无明显差异(P0.05)。末次随访时,双节段B组上、下相邻椎间隙高度显著低于双节段A组(P0.05),单节段A、B组末次随访时上、下相邻椎间隙高度无明显差异(P0.05)。末次随访时,相邻椎体骨化发生率单节段B组(32.14%)与单节段A组(6.82%)比较、双节段B组(40%)与双节段A组(9.52%)比较更高(P0.05)。根据Pfirrmann分级,双节段B组(30%)比双节段A组(4.76%)更容易发生相邻节段椎间盘退变(P0.05),单节段A、B组末次随访时相邻节段椎间盘退变无明显差异(P0.05);B组中双节段(30%)比单节段(7.14%)更容易发生相邻节段椎间盘退变(P0.05),A组中单、双节段末次随访时相邻节段椎间盘退变无明显差异(P0.05)。B组的术后吞咽困难发生率均比A组高(P0.05)。结论:颈前路单/双节段减压内固定融合手术治疗脊髓型颈椎病中,使用Zero-P与传统钛板内固定融合相比,临床疗效无明显差异,但Zero-P可减少术后相邻节段退变,且在双节段比较中优势更明显。     

Easy anchoring and smaller skin incision procedure for neuronavigation-based frameless stereoelectroencephalography

Epilepsy surgery uses both depth electrodes (DEs) and subdural electrodes (SE). DEs have mainly been developed and used in Europe. As we are able to use the DEs safely due to the current advanced level of technology, use of DEs has been increasing rapidly over the last decade. Unlike placement of SEs, which simply requires craniotomy, DE placement generally requires stereotactic techniques such as frame-based stereotactic or robotic arm-based methods. However, such methods are not always available at every epilepsy center. We therefore invented guide pipes for accurate DE placement. With this guide pipe and neuronavigation-based (NB) DE placement system, we are able to place DEs accurately. However, the disadvantages of our original procedure were a relatively large skin incision and the difficulty in anchoring DEs. The purpose of this technical note is to introduce a method to perform NB DE placement with a smaller skin incision and simple anchoring procedure. As we could make the skin incision smaller and achieved easier anchoring of DEs using a titanium plate, we hope this procedure will help facilities to perform DE placement with neuronavigation systems.     

Succession of oral bacterial colonizers on dental implant materials: An in vitro biofilm model

ObjectivesOral bacterial adhesion on dental implant materials has been extensively studied using in vitro systems but has yielded results restricted to in vitro growth patterns due to limitations in species selection, sustained fastidious anaerobe growth, and mixed culture longevity. The aim of this study was to develop an oral bacterial biofilm model consisting of colonizers representative of the oral microbiome exhibiting temporal shifts characteristic of plaque development and maturation in vivo.MethodsStreptococcus oralis, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Veillonella parvula, Fusobacterium nucleatum, and Porphyromonas gingivalis were grown in monoculture prior to combination in mixed culture. Commercially pure titanium (cpTi) and yttria-stabilized zirconia (ZrO₂) disks with polished, acid-etched, or sandblasted surfaces were prepared to evaluate oral bacterial adhesion. After 6 h, 1, 3, 7, 14 and 21 days, genomic DNA from planktonic and adherent bacteria was isolated. Quantitative polymerase chain reaction (qPCR) was used to enumerate the amount and proportion of each species.ResultsEarly-colonizing S. oralis and A. actinomycetemcomitans, dominated after 6 h prior to secondary colonization by F. nucleatum and V. parvula in planktonic (1 day) and sessile (3 days) form. A. naeslundii maintained relatively low but stable bacterial counts throughout testing. After 14 days, late-colonizing P. gingivalis became established in mixed culture and persisted, becoming the dominant species after 21 days. The composition of adherent bacteria across all substrates was statistically similar at all timepoints with notable exceptions including lower S. oralis bacterial counts on polished cpTi (3 days).SignificanceWithin the present model’s limitations, multispecies oral bacterial attachment is similar on surface-treated cpTi and ZrO₂.