经皮椎体后凸成形术对骨质疏松性椎体压缩骨折的相关并发症的预后评价

目的：评价经皮椎体后凸成形术（Percutaneous kyphoplasty,PKP）对骨质疏松性椎体压缩骨折（Osteoporotic vertebral body compression的ctures,OVCFs）的相关并发症的预后。方法：回顾性分析我院2009年5月-2011年4月收治的行PKP治疗的172例OVCFs患者,按照其并发症情况分为发生组（n=22）及未发生组（n=150）,分析并发症发生的原因及对预后的影响。结果：术后共有22例患者出现并发症,发生率12_8％。其中骨水泥渗漏15例（68．2％）,骨水泥椎弓根拖尾7例（31．8％）,未见切口感染、肺栓塞等其他并发症。两组患者麻醉情况、手术时间、术中出血量和骨水泥注入量无明显统计学差异;两组患者治疗后VAS评分、后凸Cobb角显著降低,椎体前缘高度及椎体中部高度显著增加（P〈0．05）,但组间对比均无明显统计学差异,其改善率亦未见明显统计学差异（P〉0．05）。结论：PKP治疗OVCFs可取得良好的疗效,但也会带来骨水泥渗漏、骨水泥椎弓根拖尾等并发症,虽对患者的疼痛及躯体功能等预后无明显不良影响,但部分患者可出现神经受损、肺栓塞等继发疾病,严重影响其生存质量,因此,在今后的治疗中,应严格规范各项诊疗操作,有效控制PKP并发症的发生,从而改善其生存质量。     

单球囊双侧扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折的效果分析

目的：探讨单球囊双侧扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折的临床疗效。方法：选取择期在我院接受单球囊双侧扩张椎体后凸成形术治疗骨质疏松性椎体压缩骨折的52例老年患者的临床资料,对患者的疼痛评分、椎体高度变化情况、术前和术后的后凸cobb角改善情况、术后复发情况等进行分析。结果：全部患者术后随访2-17个月,疼痛均得到缓解,术前VAS评分为8．6,术后VAS评分为2．5,差异具有统计学意义（P〈0．05）;平均椎体前缘高度恢复（56．5％±34％）,中部恢复（60．5％±35．4％）,后缘恢复（40．7％±32-3％）,矢状面排列改善明显（P〈0．05）;与术前相比,手术后患者侧位X片显示Cobb角平均改善10。（P〈0．05）。术后3例发生椎体前缘骨水泥渗漏,但未引起其他并发症;1例发生肋间神经痛,经保守治疗6个月后症状得到缓解。结论：单球囊zt-N扩张椎体后凸成形术治疗老年骨质疏松性椎体压缩骨折效果明显,值得临床推广。     

MIPPO技术联合LCP钢板内固定治疗胫腓骨远端骨折的临床疗效观察

目的:探讨MIPPO技术联合LCP钢板内固定治疗胫腓骨远端骨折的临床疗效.方法:2009年8月～2012年6月,应用MIPPO技术结合LCP钢板内固定治疗胫腓骨远端骨折29例,男18例,女9例,年龄23～52岁,平均37岁;进行随访调查,对患者的骨折愈合情况、功能恢复情况及并发症等进行评估.结果:27例患者获得随访,随访时间10～24个月.27例患者骨折全部愈合,平均骨性愈合时间3～7个月,无钢板螺钉松动或断裂,无内固定失败者.2例患者发生与关节活动方向一致轻度成角畸形愈合(＜10°);4例患者患侧踝关节活动度较对侧减少;1例患者发生晚期感染,经治疗后痊愈.按Baird-Jackson踝关节功能评分标准,优21例,良4例,中1例,差1例,优良率92.6％.结论:MIPPO技术联合LCP治疗胫腓骨远端骨折具有创伤小、固定牢靠、术后恢复快、并发症少等优点,值得临床进一步研究和推广.     

Computational simulation of the early stage of bone healing under different configurations of locking compression plates

Flexible fixation or the so-called ‘biological fixation’ has been shown to encourage the formation of fracture callus, leading to better healing outcomes. However, the nature of the relationship between the degree of mechanical stability provided by a flexible fixation and the optimal healing outcomes has not been fully understood. In this study, we have developed a validated quantitative model to predict how cells in fracture callus might respond to change in their mechanical microenvironment due to different configurations of locking compression plate (LCP) in clinical practice, particularly in the early stage of healing. The model predicts that increasing flexibility of the LCP by changing the bone–plate distance (BPD) or the plate working length (WL) could enhance interfragmentary strain in the presence of a relatively large gap size (>3 mm). Furthermore, conventional LCP normally results in asymmetric tissue development during early stage of callus formation, and the increase of BPD or WL is insufficient to alleviate this problem.     

Modelling Soft Tissue Using Biphasic Theory — A Word of Caution

In recent years the biphasic approach initiated by Mow and coworkers, has been very popular in modelling soft, hydrated, cartilage tissues as well as other soft tissues, such as the brain. This work points out that due to the inherent inability of biphasic models in their present form to account for stress-strain rate dependence resulting from the viscoelasticity of the solid phase, the applicability of these models is limited to the loading conditions producing large relative velocities of phases.     

Reasons why dynamic compression plates are inferior to locking plates in osteoporotic bone: a finite element explanation

While locking plate fixation is becoming increasingly popular for complex and osteoporotic fractures, for many indications compression plating remains the standard choice. This study compares the mechanical behaviour of the more recent locking compression plate (LCP) device, with the traditional dynamic compression plates (DCPs) in bone of varying quality using finite element modelling. The bone properties considered include orthotropy, inhomogeneity, cortical thinning and periosteal apposition associated with osteoporosis. The effect of preloads induced by compression plating was included in the models. Two different fracture scenarios were modelled: one with complete reduction and one with a fracture gap. The results show that the preload arising in DCPs results in large principal strains in the bone all around the perimeter of the screw hole, whereas for LCPs large principal strains occur primarily on the side of the screw proximal to the load. The strains within the bone produced by the two screw types are similar in healthy bone with a reduced fracture gap; however, the DCP produces much larger strains in osteoporotic bone. In the presence of a fracture gap, the DCP results in a considerably larger region with high tensile strains and a slightly smaller region with high compressive strains. These findings provide a biomechanical basis for the reported improved performance of locking plates in poorer bone quality.     

Vertebral deformities in interspecific diploid and triploid salmonid hybrids

Vertebral deformities in salmonid interspecific hybrids, some of which were triploidised, were assessed across three separate year classes during the freshwater life stage. Initially, eggs from a farmed Atlantic salmon Salmo salar were crossed with the sperm from a S. salar, arctic char Salvelinus alpinus or brown trout Salmo trutta. For S. salar × S. trutta, half the eggs were triploidised. In a second- and third-year class, the eggs from a farmed S. salar were crossed with the sperm from either a S. salar or a S. trutta, and half of each group was triploidised. In the two initial-year classes, all hybrids were larger than the S. salar controls, and triploid S. salar × S. trutta were larger than diploid counterparts. In the third-year class, the S. salar × S. trutta were smaller than the S. salar, in contrast to the initial 2 year classes, although the triploid hybrids were still larger than the diploids. In the third-year class, a high degree of spontaneous triploidy was also observed in the putative diploid groups (between 16 and 39%). Vertebral deformities were consistently higher in pressure-shocked triploids than diploids, irrespective of hybridisation, but there was no consistent effect of hybridisation among experiments. Although this study was not able to explain the contrasting results for vertebral deformities between year classes, triploid S. salar × S. trutta can demonstrate impressive freshwater growth that could be of interest for future farming programmes.