Augmentation of anterior vertebral body screw fixation by an injectable, biodegradable calcium phosphate bone substitute.

STUDY DESIGN: A biomechanical study to evaluate the effects of a biodegradable calcium phosphate (Ca-P) bone substitute on the fixation strength and bending rigidity of vertebral body screws. OBJECTIVES: To determine if an injectable, biodegradable Ca-P bone substitute provides significant augmentation of anterior vertebral screw fixation in the osteoporotic spine. SUMMARY OF BACKGROUND DATA: Polymethylmethacrylate (PMMA) augmented screws have been used clinically; however, there is concern about thermal damage to the neural elements during polymerization of the PMMA as well as its negative effects on bone remodeling. Injectable, biodegradable Ca-P bone substitutes have shown enhanced fixation of pedicle screws. METHODS: Sixteen fresh cadaveric thoracolumbar vertebrae were randomly divided into two groups: control (no augmentation) (n = 8) and Ca-P bone substitute augmentation (n = 8) groups. Bone-screw fixation rigidity in bending was determined initially and after 10(5) cycles, followed by pullout testing of the screw to failure to determine pullout strength and stiffness. RESULTS: The bone-screw bending rigidity for the Ca-P bone substitute group was significantly greater than the control group, initially (58%) and after cyclic loading (125%). The pullout strength for Ca-P bone substitute group (1848 +/- 166 N) was significantly greater than the control group (665 +/- 92 N) (P < 0.01). Stiffness in pullout for the Ca-P bone substitute groups (399 +/- 69 N/mm) was significantly higher than the control group (210 +/- 51 N/mm) (P < 0.01). CONCLUSION: This study demonstrated that augmentation of anterior vertebral body screw fixation with a biodegradable Ca-P bone substitute is a potential alternative to the use of PMMA cement.     

Biomechanical evaluation of kyphoplasty with calcium sulfate cement in a cadaveric osteoporotic vertebral compression fracture model.

BACKGROUND CONTEXT: Vertebral compression fractures can cause deformity, pain, and disability. Kyphoplasty involves percutaneous insertion of an inflatable balloon tamp into a fractured vertebra followed by injection of polymethylmethacrylate (PMMA) bone cement. PMMA has several disadvantages such as potential thermal necrosis and monomer toxicity. Calcium sulfate cement (CSC) is nontoxic, osteoconductive, and bioabsorbable. PURPOSE: To evaluate the biomechanical performance of CSC for kyphoplasty in cadaveric osteoporotic vertebral bodies. STUDY DESIGN: Destructive biomechanical tests using fresh cadaveric thoracolumbar vertebral bodies. METHODS: Thirty-three vertebral bodies (T9 to L4) from osteoporotic cadaveric spines were disarticulated, stripped of soft tissue, and measured for height and volume. Each vertebral body was compressed at 0.5 mm/s using a hinged plating system on a materials testing machine to create an anterior wedge fracture and reduce the anterior height by 25%. Pretreatment strength and stiffness were measured. Two KyphX inflatable balloon tamps were used to reexpand each vertebral body. After randomization, three groups were created: Group A-no cement; Group B-PMMA; Group C-calcium sulfate cement. Groups B and C were filled with the corresponding cement to 25% of the vertebral body volume. All vertebral bodies were then recompressed by 25% of the post-kyphoplasty anterior height to obtain posttreatment strength and stiffness. RESULTS: Treatment with PMMA restored vertebral strength to 127% of the intact level (4168.2 N+/-2288.7) and stiffness to 70% of the intact level (810.0 N/mm+/-380.6). Treatment with CSC restored strength to 108% of the intact level (3429.6 N+/-2440.7) and stiffness to 46% of the intact level (597.7 N/mm+/-317.5). CSC and PMMA were not significantly different for strength restoration (p=.4). Significantly greater strength restoration was obtained with either PMMA or CSC, compared with the control group (p=.003 and .03, respectively). Stiffness restoration tended to be greater with PMMA than for CSC, but this difference was not statistically significant (p=.1). Both cements had significantly greater stiffness when compared with the control group (p=.001 and p=.04, respectively). CONCLUSIONS: Use of CSC for kyphoplasty yields similar vertebral body strength and stiffness as compared with PMMA. It may be a useful alternative bone cement for kyphoplasty. Further studies are required to assess the bioabsorption of CSCs after kyphoplasty in vivo.     

胸腰椎骨质疏松性骨折自固化磷酸钙骨水泥椎体成形的实验研究

目的探讨自固化磷酸钙骨水泥(calciumphosphatecement,CPC)注射椎体成形术后对胸腰椎骨质疏松性骨折椎体的力学影响。方法自愿捐赠的4具甲醛固定的老年尸体,取胸腰椎骨质疏松标本,平均年龄69岁,男、女各2具。每具标本随机取6个椎体,制备24个单椎体标本,建立前屈方向加载单椎体骨折模型。将CPC粉末与固化液以2.5g∶1ml调和制备CPC骨水泥,对骨折标本行CPC成形强化,每个椎体注射CPC约4ml。分别进行骨折前、成形后屈曲压缩力学检测。结果骨质疏松椎体标本骨折前最大载荷为1954±46N,位移长度为5.60±0.70mm,刚度为349±18N/mm;骨折间隙CPC填塞成形后最大载荷为2285±34N,位移为5.35±0.60mm,刚度为427±10N/mm,各指标骨折前和成形后比较差异均有统计学意义(P<0.05)。CPC加强成形后单椎体的承载能力强度较骨折前提高16.92%,刚度较骨折前提高22.31%。结论椎体内注射CPC能明显恢复骨质疏松骨折椎体的力学性能。     

Biomechanical efficacy of unipedicular versus bipedicular vertebroplasty for the management of osteoporotic compression fractures.

STUDY DESIGN: Cadaveric study on the biomechanics of osteoporotic vertebral bodies augmented and not augmented with polymethylmethacrylate cement. OBJECTIVES: To determine the strength and stiffness of osteoporotic vertebral bodies subjected to compression fractures and 1) not augmented, 2) augmented with unipedicular injection of cement, or 3) augmented with bipedicular injection of cement. SUMMARY OF BACKGROUND DATA: Percutaneous vertebroplasty is a relatively new method of managing osteoporotic compression fractures, but it lacks biomechanical confirmation. METHODS: Fresh vertebral bodies (L2-L5) were harvested from 10 osteoporotic spines (T scores range, -3.7 to -8.8) and compressed in a materials testing machine to determine intact strength and stiffness. They were then repaired using a transpedicular injection of cement (unipedicular or bipedicular), or they were unaugmented and recrushed. RESULTS: Results suggest that unipedicular and bipedicular cement injection restored vertebral body stiffness to intact values, whereas unaugmented vertebral bodies were significantly more compliant than either injected or intact vertebral bodies. Vertebral bodies injected with cement (both bipedicular and unipedicular) were significantly stronger than the intact vertebral bodies, whereas unaugmented vertebral bodies were significantly weaker. There was no significant difference in loss in vertebral body height between any of the augmentation groups. CONCLUSIONS: This study suggests that unipedicular and bipedicular injection of cement, as used during percutaneous vertebroplasty, increases acute strength and restores stiffness of vertebral bodies with compression fractures.     

Mechanical augmentation of the vertebral body by calcium phosphate cement injection

The effectiveness of transpedicular calcium phosphate cement (CPC) injection as a new treatment for osteoporotic compression fracture of vertebrae was evaluated by measuring the compressive strength and the mode of failure in vertebrae experimentally injected with CPC. Forty-five human cadaver vertebrae were divided into three groups: a control group; group A, in which CPC was injected into the upper half of the vertebral body; and group B, in which CPC was injected into the whole vertebra. The load-displacement curve characteristically had two peaks in group A, and decreased rapidly after failure in group B. The failure site was the cancellous bone immediately below the cranial endplate in the control group, cancellous bone immediately below the CPC injection area in group A, and in the CPC injection area in group B. Although mechanical strength was greatest in those vertebrae in which the entire cancellous bone was replaced with CPC, the compressive strength of the vertebrae was also increased by partial replacement of cancellous bone with CPC injection. In terms of mode of failure and mechanical gradient with adjacent vertebrae, there were several advantages for those vertebrae in which the cranial half of the cancellous bone was replaced with CPC. Received: May 29, 2000 / Accepted: September 20, 2000     

经皮椎体成形术自固化磷酸钙人工骨充填治疗骨质疏松性胸腰椎压缩性骨折

目的探讨应用经皮椎体成形术(PVP)自固化磷酸钙人工骨(CPC)充填治疗骨质疏松性胸腰椎压缩性骨折的临床疗效。方法自2004年1月起,对26例29个椎体骨质疏松性胸腰椎压缩骨折患者,采用术中手法复位、PVP自固化CPC充填治疗。结果26例患者经单侧或双侧椎弓根穿刺椎体成形术成功治愈。胸腰椎自固化CPC平均充填量为4.6mL。术中CPC渗漏者5例5个椎体。无一例出现严重并发症。经3～8个月(平均4.6个月)随访,术后所有患者疼痛消失。除3例椎体高度丢失15%外,其余椎体高度平均恢复达正常的80%。结论PVP自固化CPC充填治疗骨质疏松性胸腰椎压缩性骨折是一种安全、简单、有效的方法。     

不同充填材料应用于山羊经皮椎体成形术的组织学研究

目的:研究聚甲基丙烯酸甲酯(PMMA)、磷酸钙人工骨(CPC)和复合重组人骨形态发生蛋白-2的磷酸钙人工骨(rhBMP-2/CPC)在山羊骨质疏松症模型上行经皮椎体成形术(PVP)后的组织学表现。方法:6～8岁雌性山羊8只,均行双侧卵巢切除术,术后4个月建立骨质疏松症模型。在C形臂X线机监视下,随机选取8只山羊的L2-L6的两节椎体行PVP,分别充填PMMA、CPC和rhBMP-2/CPC,保证每只山羊的两节穿刺椎体的充填材料各不相同,术后4个月处死所有动物,取出椎体,组织学观察。结果:8只山羊16个椎体的PVP均成功,共出现4个椎体的渗漏。肉眼观察:PMMA与松质骨界限清晰,一个椎体取材时交界面出现破碎和脱落现象;而CPC和rhBMP-2/CPC与椎体内松质骨界限不清,互相融合生长。HE染色光镜观察:PMMA与骨小梁松散结合,界限明显,未见PMMA吸收和新生骨形成;CPC均匀分布于骨小梁和骨髓组织内,有CPC吸收现象,同时可见有新生软骨样团块形成,并有新生骨组织形成向其中心长入;rhBMP-2/CPC除了CPC的表现外,可见成骨活动活跃。结论:在组织学上,rhBMP-2/CPC和CPC均具有降解活性和骨传导活性,优于PMMA。rhBMP-2/CPC还具有诱导成骨活性,可能成为PVP中强化骨质疏松性椎体的首选充填材料。     

Biomechanical evaluation of kyphoplasty and vertebroplasty with calcium phosphate cement in a simulated osteoporotic compression fracture

 Kyphoplasty and vertebroplasty with polymethylmethacrylate (PMMA) have been used for the treatment of osteoporotic vertebral compression fractures. We performed kyphoplasty and vertebroplasty with α-tricalcium phosphate cement (CPC) and PMMA to compare the biomechanical properties. Thirty osteoporotic vertebrae were harvested from nine embalmed cadavers. We randomized the vertebrae into four treatment groups: (1) kyphoplasty with CPC; (2) kyphoplasty with PMMA; (3) vertebroplasty with CPC; and (4) vertebroplasty with PMMA. Prior to injecting the cement, all vertebrae were compressed to determine their initial strength and stiffness. They were then recompressed to determine their augmented strength and stiffness. Although the augmented strength was greater than the initial strength in all groups, there was no significant difference between the two bone cements for either kyphoplasty or vertebroplasty. The augmented stiffness was significantly less than the initial stiffness in the kyphoplasty groups, but the difference between the two cements did not reach significance. In the vertebroplasty groups, the augmented stiffness was not significantly different from the initial stiffness. There was no significant difference between the two bone cements for either procedure when cement volume and restoration of anterior height were assessed. We concluded that kyphoplasty and vertebroplasty with CPC were viable treatment alternatives to PMMA for osteoporotic vertebral compression fractures. Received: July 18, 2002 / Accepted: November 6, 2002 Offprint requests to: S. Tomita     

Biomechanical evaluation of a new bone cement for use in vertebroplasty

STUDY DESIGN: Comparative ex vivobiomechanical study. OBJECTIVES: To determine the strength and stiffness of osteoporotic vertebral bodies subjected to compression fractures and subsequently stabilized via bipedicular injection of one of two bone cements: one is a commercially available polymethylmethacrylate (Simplex P) and one is a proprietary glass-ceramic-reinforced BisGMA/BisEMA/TEGDMA matrix composite that is being developed for use in vertebroplasty (Orthocomp). SUMMARY OF BACKGROUND DATA: Osteoporotic compression fractures present diagnostic and therapeutic challenges for the clinician. Vertebroplasty, a new technique for treating such fractures, stabilizes vertebral bodies by injection of cement. Little is known, however, about the biomechanics of this treatment. METHODS: Five vertebral bodies (L1-L5) from each of four fresh spines were harvested from female cadavers (age, 80 +/- 5 years), screened for bone density using DEXA (t = -3.4 to -6.4), disarticulated, and compressed in a materials testing machine to determine initial strength and stiffness. The fractures then were repaired using a transpedicular injection of either Orthocomp or Simplex P and recrushed. RESULTS: For both cement treatments, vertebral body strength after injection of cement was significantly greater than initial strength values. Vertebral bodies augmented with Orthocomp recovered their initial stiffness; however, vertebral bodies augmented with Simplex P were significantly less stiff than they were in their initial condition. CONCLUSIONS: Augmentation with Orthocomp results in similar or greater mechanical properties compared with Simplex P, but these biomechanical results have yet to be substantiated in clinical studies.     

Biomechanical evaluation of vertebroplasty using calcium sulfate cement for thoracolumbar burst fractures

OBJECTIVE: To evaluate the biomechanical performance of vertebroplasty using calcium sulfate cement for thoracolumbar burst fractures. METHODS: Sixteen bovine thoracolumbar spines (T11-L1) were divided into 4 groups (A,B,C and D). After burst-fracture model was created, 12 vertebral bodies in Groups A, B and C were augmented with calcium sulfate cement (CSC), calcium phosphate cement (CPC) and polymethylmethacrylate (PMMA) bone cement, respectively. Each anterior vertebral body height was measured with a caliper at 4 time points: intact conditions (HInt), post-fracture (HFr), post-reduction (HRe) and post-vertebroplasty (HVP). The filling volume of 3 different bone cements was also measured. Each vertebral body was compressed at 0.5 mm/s using a hinged plating system on a materials testing machine to 50% of the post-vertebroplasty height to determine strength and stiffness. Difference was checked using t test or One-way ANOVA. RESULTS: The average strike energy was 66.2 J. Vertebroplasty with different cements could sustain vertebral height.The average filling volume of bone cement in 3 groups was 4.35 ml (CSC), 3.72 ml (CPC) and 3.95 ml (PMMA), respectively, and there was no statistically significant difference among them (P larger than 0.05). Vertebroplasty with PMMA completely restored strength (116%) and stiffness (105%). CSC or CPC partly recovered vertebral strength and stiffness. However, greater strength restoration was got with CSC (1659 N) as compared with CPC (1011N, P less than 0.01). Regarding stiffness, differences between CSC (140 N/mm+/-40 N/mm)and the other two bone cements (CPC:148 N/mm+/-33 N/mm, PMMA:236 N/mm+/-97 N/mm) were not significant (P larger than 0.05). CONCLUSIONS: For a burst-fracture of calf spine, use of CSC for vertebroplasty yields similar vertebral stiffness as compared with PMMA or CPC. Although augmentation with CSC partly obtains the normal strength, this treatment still can be applied in thoracolumbar burst fractures with other instrumental devices in light of its bioactivation.     

A rat osteoporotic spine model for the evaluation of bioresorbable bone cements.

BACKGROUND CONTEXT: As the aging population increases, the rising prevalence of osteoporosis-related spine fractures will have a dramatic impact on health care. At present, mainstay treatment relies on systemic medications intended to prevent diminishing bone mineral density (BMD) and bone mass. However, an adjunctive treatment strategy is to target specific areas of the skeletal system that are prone to clinically significant osteoporotic fractures. We term this strategy the "local treatment of osteoporosis" or osteoplasty. Potential use of osteoplasty involves the percutaneous injection of bioresorbable and bioactive bone cements into bones at risk of sustaining osteoporotic fractures. Calcium sulfate (CaSO(4)) is among the candidate bioresorbable bone cements with the material attributes desirable for potential application with osteoplasty, yet previous studies on the osteoconductive properties of CaSO(4) have been limited to animal models exhibiting normal bone biology and architecture. However, osteoporotic bone physiology may potentially interfere with the material properties of common osteoconductive biomaterials, such as that of CaSO(4). To further test this hypothesis, a suitable animal model is needed to evaluate the in vivo behavior of potential biomaterials in osteoporotic bone. PURPOSE: The purpose of this study is to evaluate the caudal (proximal tail) rat vertebral body as an appropriate system for the in vivo evaluation of bone cement performance in the osteoporotic spine. STUDY DESIGN: (1) Micro-computed tomography radiomorphometry study and (2) biomechanical vertebral compression analysis. METHODS: Female Sprague Dawley rats were ovarectomized (OVX) at age 8 weeks and subsequently maintained on a low-calcium diet for 3 months. Normal nonovarectomized female rats (NL) of similar age and size were maintained on regular rodent feed. Micro-CT analysis was performed on both the lumbar and caudal vertebrae (levels 5-7) of both groups. The following bone radiomorphometric parameters were determined: bone mineral density (BMD), average cortical thickness (ACT), average trabecular thickness (TbTh), and average trabecular spacing (TbSp). Strength and stiffness of both NL and OVX vertebral bodies were assessed under axial compression at 0.1 mm/s, whereas displacement (mm) and force (N) were measured at 10 Hz until completion to failure. After the implantation of an injectable form of CaSO(4) bone cement into caudal vertebrae, radiomorphometric analysis of cement volume, based on its unique CT absorption profile, was performed over the 8-week time period, as well as the subsequent bone response of both NL and OVX caudal vertebrae to CaSO4. RESULTS: OVX caudal vertebrae showed an 18% decrease in BMD, a 28% decrease in diaphyseal ACT, a 55% decrease in TbTh, and a 2.4-fold increase in TbSp compared with NL (p<.05). Additionally, lumbar vertebrae exhibited a 21% decrease in BMD, a 24% decrease in anterior body ACT, a 48% decrease in TbTh, and a 4.7-fold increase in TbSp (p<.05). Failure testing of OVX caudal vertebral bodies revealed a 29% decrease in strength and a 60% decrease in stiffness compared with NL (p<.01). After implantation into OVX caudal vertebrae, CaSO(4) cement exhibited a 50% decrease in initial cement volume at 2 weeks and complete resorption by 4 weeks, whereas CaSO(4) injected into NL vertebrae exhibited a 79% decrease in initial cement volume at 4 weeks, trace amounts at 6 weeks, and complete resorption by 8 weeks. At 8 weeks, NL vertebrae implanted with CaSO(4) cement exhibited increased cortical bone thickness compared with NL sham vertebrae. This CaSO(4) cement-mediated bone augmentation was altered in osteoporotic vertebrae that exhibited porous irregular cortical bone not noted in cement-treated NL vertebrae or OVX sham vertebrae. CONCLUSIONS: Future investigation of potential biomaterials intended for the local treatment of osteoporosis will require their study within an appropriate osteoporosis animal model. The OVX rat caudal spine exhibits pathologic bone changes consistent with the osteoporosis phenotype, including decreased BMD, diminished trabecular network density, cortical thinning, and decreased mechanical strength. These derangements in bone microarchitecture and physiology may contribute toward the accelerated cement resorption and altered bone response to CaSO4 observed in this study. Important advantages of the OVX rat caudal spine are the rapid and minimally invasive surgical exposure of the vertebral body and the ease of cement injection. We propose that the OVX rat caudal spine represents a valuable and cost-effective tool in the armamentarium of investigators evaluating biomaterials designed for implantation into the osteoporotic spine.     

经皮椎体后凸成形术中分步推注骨水泥治疗椎体后壁破损的骨质疏松性椎体骨折

目的 探讨经皮椎体后凸成形术（PKP）治疗椎体后壁破损的骨质疏松性椎体骨折中减少骨水泥渗漏的方法.方法 对27例老年骨质疏松性骨折患者在PKP术中采用分步推注骨水泥的方法治疗椎体后壁破损36椎,观察患者手术前后疼痛视觉模拟评分（VAS）变化、椎体高度恢复情况及骨水泥渗漏情况.结果 27例均获得随访,时间12~48（27.3±6.2）个月.术后3 d及末次随访时患者VAS、椎体高度均较术前明显改善（P〈0.05）,末次随访时与术后3 d比较差异无统计学意义（P〉0.05）.术后5个椎体（13.8%）发生骨水泥渗漏,其中椎旁渗漏2个,椎间盘渗漏2个,椎管内渗漏1个.无肺栓塞发生,未出现脊髓和神经根损伤.结论 PKP治疗椎体后壁破损老年骨质疏松性椎体压缩性骨折中,采用分步推注骨水泥的方法可有效减少骨水泥渗漏.     

Restoring geometric and loading alignment of the thoracic spine with a vertebral compression fracture: effects of balloon (bone tamp) inflation and spinal extension.

BACKGROUND CONTEXT: In patients with osteoporosis, changes in spinal alignment after a vertebral compression fracture (VCF) are believed to increase the risk of fracture of the adjacent vertebrae. The alterations in spinal biomechanics as a result of osteoporotic VCF and the effects of deformity correction on the loads in the adjacent vertebral bodies are not fully understood. PURPOSE: To measure 1) the effect of thoracic VCFs on kyphosis (geometric alignment) and the shift of the physiologic compressive load path (loading alignment), 2) the effect of fracture reduction by balloon (bone tamp) inflation in restoring normal geometric and loading alignment and 3) the effect of spinal extension alone on fracture reduction and restoration of normal geometric and loading alignment. STUDY DESIGN/SETTING: A biomechanical study using six fresh human thoracic specimens, each consisting of three adjacent vertebrae with all soft tissues and bony structures intact. METHODS: In order to reliably create fracture, cancellous bone in the middle vertebral body was disrupted by inflation of bone tamps. After removal of the bone tamps, the specimen was compressed using bilateral loading cables until a fracture was observed with anterior vertebral body height loss of >/=25%. Fracture reduction was performed under a compressive preload of 250 N first under the application of extension moments, and then using inflatable bone tamps. The vertebral body heights, kyphotic deformity of the fractured vertebra and adjacent segments and location of compressive load (cable) path in the fractured and adjacent vertebral bodies were measured on video-fluoroscopic images. RESULTS: The VCF caused anterior wall height loss of 37+/-15%, middle-height loss of 34+/-16%, segmental kyphosis increase of 14+/-7.0 degrees and vertebral kyphosis increase of 13+/-5.5 degrees (p<.05). The compressive load path shifted anteriorly by about 20% of anteroposterior end plate width in the fractured and adjacent vertebrae (p=.008). Bone tamp inflation restored the anterior wall height to 91+/-8.9%, middle-height to 91+/-14% and segmental kyphosis to within 5.6+/-5.9 degrees of prefracture values. The compressive load path returned posteriorly relative to the postfracture location in all three vertebrae (p=.004): the load path remained anterior to the prefracture location by about 9% to 11% of the anteroposterior end plate width. With application of extension moment (6.3+/-2.2 Nm) until segmental kyphosis and compressive load path were fully restored, anterior vertebral body heights were improved to 85+/-8.6% of prefracture values. However, the middle vertebral body height was not restored and vertebral kyphotic deformity remained significantly larger than the prefracture values (p<.05). CONCLUSIONS: The anterior shift of the compressive load path in vertebral bodies adjacent to VCF can induce additional flexion moments on these vertebrae. This eccentric loading may contribute to the increased risk of new fractures in osteoporotic vertebrae adjacent to an uncorrected VCF deformity. Bone tamp inflation under a physiologic preload significantly reduced the VCF deformity (anterior and middle vertebral body heights, segmental and vertebral kyphosis) and returned the compressive load path posteriorly, approaching the prefracture alignment. Application of extension moments also was effective in restoring the prefracture geometric and loading alignment of adjacent segments, but the middle height of the fractured vertebra and vertebral kyphotic deformity were not restored with spinal extension alone.     

椎体后凸成形术中灌注不同凝固状态骨水泥对骨质疏松性椎体压缩性骨折绵羊椎体生物力学的影响

目的 探讨椎体后凸成形术中灌注不同凝固状态骨水泥对骨质疏松性椎体压缩性骨折(OVCF)绵羊椎体强度和刚度的影响.方法 选取成年绵羊8只,获得L1～5椎体40个,随机分为4组,每组10个.采用3％稀盐酸浸泡和双侧椎弓根微泵灌注法制作骨质疏松椎体模型,再将骨质疏松椎体置于衡翼生物力学机上并压缩其高度的1/4制作压缩骨折椎体模型.制备骨水泥灌注通道后,用球囊经双侧椎弓根复位骨折椎体,在C形臂X线机透视下,对照组(A组)不灌注骨水泥,其余各组分别在聚甲基丙烯酸甲酯(PMMA)骨水泥粉液混合后2 min(骨水泥稀薄期,B组)、4 min(骨水泥黏稠期,C组)、6 min(骨水泥凝固期,D组)灌注骨水泥.室温放置24 h待骨水泥凝固.分别于术前和术后测量各组椎体的强度和刚度.结果 术前4组椎体强度和刚度组间比较,差异均无统计学意义(P>0.05).A组术后椎体强度低于术前,B、C、D组术后椎体强度均高于术前,差异有统计学意义(P<0.05).4组术后椎体刚度均低于术前,差异有统计学意义(P<0.05).B、C、D组术后椎体强度和刚度均高于A组,差异有统计学意义(P<0.05);B、C组术后椎体强度和刚度均高于D组,差异有统计学意义(P<0.05);B组和C组术后椎体强度和刚度差异无统计学意义(P>0.05).结论 OVCF绵羊采用椎体后凸成形术治疗,注入稀薄期和黏稠期骨水泥的椎体强度和刚度均高于注入凝固期骨水泥的椎体.注入不同凝固状态骨水泥均可增强椎体强度,但椎体刚度均恢复不到未骨折时期状态.     

椎体成形术填充剂最优化分布模式三维有限元分析

目的:通过建立骨质疏松三维有限元模型,模拟液体流动进入椎体,研究不同状态骨水泥灌注量及分布条件下经皮椎体成形术术后伤椎刚度恢复及相邻椎体应力分析.方法:选取男性健康志愿者一名,从T11到L2之间使用CT扫描,采用Mimics 15.0以及ABAQUS6.11等软件提取CT图像,建立骨质疏松性骨折椎体模型,将模拟流动物理...     

经皮椎体成形术中骨水泥注射量与疗效和并发症的相关性研究

目的 探讨经皮椎体成形术(PVP)在治疗骨质疏松性椎体压缩骨折中骨水泥注射量与疗效的关系,以及骨水泥渗漏的预防.方法 2002年1月至2007年2月,应用PVP治疗骨质疏松性椎体压缩骨折121例,共163个椎体,其中胸椎101个,腰椎62个.患者在C型臂X线机临测或者CT定位下行PVP治疗.将骨水泥的注射量与椎体病变体积的比例分为4级:1级充填比例<25%,2级填允比例25%～50%,3级填充比例51%～75%,4级填充比例>75%,术后行X线片及CT检查并分析骨水泥在椎体的分布,评价骨水泥的渗漏、疼痛缓解情况及脊柱的稳定性.疼痛缓解采用WHO标准进行评估.结果 121例患者骨水泥注射量平均为(4.2±0.8)mL.骨水泥填允比例具体分布为1级64个,2级72个,3级27个椎体,胸椎注射1～2 mL 18个,腰椎注射2～3 mL 11个椎体.1、2、3级椎体骨水泥渗漏率分别为18.8%、29.2%和48.1%.121例患者术后获6～24个月(平均9.8个月)随访,患者背部疼痛均有不同程度缓解或者消失.填充比例为1级、2级、3级各组之间的疼痛缓解差异无统计学意义(χ2=0.059,P>0.05).填允比例为2、3级患者椎体前、中、后缘高度及Cobb角在于术前后差异有统计学意义(P<0.05),而1级患者差异无统计学意义(P>0.05).结论 PVP在治疗骨质疏松性椎体压缩骨折中,骨水泥的注入量与临床效果之间无必然联系,从治疗的安全性考虑,手术时应适当限量注射骨水泥(胸椎1～2 mL,腰椎2～3 mL),且应使骨水泥分布均匀.     

经皮椎体成形术中骨水泥注射量与疗效和并发症的相关性研究

目的 探讨经皮椎体成形术(PVP)在治疗骨质疏松性椎体压缩骨折中骨水泥注射量与疗效的关系,以及骨水泥渗漏的预防.方法 2002年1月至2007年2月,应用PVP治疗骨质疏松性椎体压缩骨折121例,共163个椎体,其中胸椎101个,腰椎62个.患者在C型臂X线机临测或者CT定位下行PVP治疗.将骨水泥的注射量与椎体病变体积的比例分为4级:1级充填比例<25%,2级填允比例25%～50%,3级填充比例51%～75%,4级填充比例>75%,术后行X线片及CT检查并分析骨水泥在椎体的分布,评价骨水泥的渗漏、疼痛缓解情况及脊柱的稳定性.疼痛缓解采用WHO标准进行评估.结果 121例患者骨水泥注射量平均为(4.2±0.8)mL.骨水泥填允比例具体分布为1级64个,2级72个,3级27个椎体,胸椎注射1～2 mL 18个,腰椎注射2～3 mL 11个椎体.1、2、3级椎体骨水泥渗漏率分别为18.8%、29.2%和48.1%.121例患者术后获6～24个月(平均9.8个月)随访,患者背部疼痛均有不同程度缓解或者消失.填充比例为1级、2级、3级各组之间的疼痛缓解差异无统计学意义(χ2=0.059,P>0.05).填允比例为2、3级患者椎体前、中、后缘高度及Cobb角在于术前后差异有统计学意义(P<0.05),而1级患者差异无统计学意义(P>0.05).结论 PVP在治疗骨质疏松性椎体压缩骨折中,骨水泥的注入量与临床效果之间无必然联系,从治疗的安全性考虑,手术时应适当限量注射骨水泥(胸椎1～2 mL,腰椎2～3 mL),且应使骨水泥分布均匀.     

经皮椎体成形术中骨水泥注射量与疗效和并发症的相关性研究

目的 探讨经皮椎体成形术(PVP)在治疗骨质疏松性椎体压缩骨折中骨水泥注射量与疗效的关系,以及骨水泥渗漏的预防.方法 2002年1月至2007年2月,应用PVP治疗骨质疏松性椎体压缩骨折121例,共163个椎体,其中胸椎101个,腰椎62个.患者在C型臂X线机临测或者CT定位下行PVP治疗.将骨水泥的注射量与椎体病变体积的比例分为4级:1级充填比例<25%,2级填允比例25%～50%,3级填充比例51%～75%,4级填充比例>75%,术后行X线片及CT检查并分析骨水泥在椎体的分布,评价骨水泥的渗漏、疼痛缓解情况及脊柱的稳定性.疼痛缓解采用WHO标准进行评估.结果 121例患者骨水泥注射量平均为(4.2±0.8)mL.骨水泥填允比例具体分布为1级64个,2级72个,3级27个椎体,胸椎注射1～2 mL 18个,腰椎注射2～3 mL 11个椎体.1、2、3级椎体骨水泥渗漏率分别为18.8%、29.2%和48.1%.121例患者术后获6～24个月(平均9.8个月)随访,患者背部疼痛均有不同程度缓解或者消失.填充比例为1级、2级、3级各组之间的疼痛缓解差异无统计学意义(χ2=0.059,P>0.05).填允比例为2、3级患者椎体前、中、后缘高度及Cobb角在于术前后差异有统计学意义(P<0.05),而1级患者差异无统计学意义(P>0.05).结论 PVP在治疗骨质疏松性椎体压缩骨折中,骨水泥的注入量与临床效果之间无必然联系,从治疗的安全性考虑,手术时应适当限量注射骨水泥(胸椎1～2 mL,腰椎2～3 mL),且应使骨水泥分布均匀.     

经皮椎体成形术中骨水泥注射量与疗效和并发症的相关性研究

目的 探讨经皮椎体成形术(PVP)在治疗骨质疏松性椎体压缩骨折中骨水泥注射量与疗效的关系,以及骨水泥渗漏的预防.方法 2002年1月至2007年2月,应用PVP治疗骨质疏松性椎体压缩骨折121例,共163个椎体,其中胸椎101个,腰椎62个.患者在C型臂X线机临测或者CT定位下行PVP治疗.将骨水泥的注射量与椎体病变体积的比例分为4级:1级充填比例<25%,2级填允比例25%～50%,3级填充比例51%～75%,4级填充比例>75%,术后行X线片及CT检查并分析骨水泥在椎体的分布,评价骨水泥的渗漏、疼痛缓解情况及脊柱的稳定性.疼痛缓解采用WHO标准进行评估.结果 121例患者骨水泥注射量平均为(4.2±0.8)mL.骨水泥填允比例具体分布为1级64个,2级72个,3级27个椎体,胸椎注射1～2 mL 18个,腰椎注射2～3 mL 11个椎体.1、2、3级椎体骨水泥渗漏率分别为18.8%、29.2%和48.1%.121例患者术后获6～24个月(平均9.8个月)随访,患者背部疼痛均有不同程度缓解或者消失.填充比例为1级、2级、3级各组之间的疼痛缓解差异无统计学意义(χ2=0.059,P>0.05).填允比例为2、3级患者椎体前、中、后缘高度及Cobb角在于术前后差异有统计学意义(P<0.05),而1级患者差异无统计学意义(P>0.05).结论 PVP在治疗骨质疏松性椎体压缩骨折中,骨水泥的注入量与临床效果之间无必然联系,从治疗的安全性考虑,手术时应适当限量注射骨水泥(胸椎1～2 mL,腰椎2～3 mL),且应使骨水泥分布均匀.