椎弓根外穿刺行单侧PVP或PKP术治疗上中位胸椎椎体骨折

目的:探讨椎弓根外穿刺行单侧PVP或PKP术治疗上中位胸椎骨质疏松性压缩骨折(OVCFs)的特点与疗效。方法:回顾性分析2004年11月～2010年3月我院收治的上、中胸椎OVCFs患者26例39个椎体,均采用椎弓根外穿刺行单侧PVP或PKP术,其中男8例,女18例;平均年龄71.3±1.3岁;原发性OVCFs 19例,继发OVCFs 7例。骨折时间平均3.5周,骨折椎体分布:T3 1个、T4 3个,T5 4个,T6 4个,T7 6个、T8 10个、T9 6个、T10 5个。1个节段17例,2个节段5例,3个节段4例。PVP 15例27个节段,PKP 11例12个节段。术中观察穿刺针针尖达到椎体中线的比率,术后1d及末次随访时测量骨折椎体前缘和椎体中间高度的恢复值、VAS评分的改善率、骨水泥向椎体外渗漏率以及患者的满意度。结果:39个椎体均经单侧胸椎椎弓根外途径穿刺完成PVP和PKP操作。均穿刺成功、骨水泥在椎体内左右对称分布。手术时间为25～35min/椎,无穿刺并发症。骨水泥平均注射量3.5ml/椎。骨水泥渗漏4例,渗漏率10.25%。平均随访时间14个月。VAS评分术前平均为9.8±0.3分,术后1d平均为5.7±0.4分,末次随访时为3.3±0.4分,术前与术后1d及末次随访时的VAS评分比较,疼痛均得到了明显改善(P<0.05);椎体前缘高度恢复值和椎体中间高度恢复值分别为为63.1±18.6%和68.5±25.3%,均较术前明显恢复(P<0.05)。患者对治疗的满意率达100%。结论:治疗上、中位胸椎骨质疏松性压缩性骨折,椎弓根外穿刺行单侧PVP和PKP术是一种安全、可行和有效的治疗方法。     

经皮椎体成形术与椎体后凸成形术治疗胸腰椎压缩性骨折的临床疗效比较

目的比较经皮椎体成形术与椎体后凸成形术治疗胸腰椎压缩性骨折的临床疗效。方法对98例胸腰椎压缩性骨折，根据手术方法不同分为椎体成形组和椎体后凸成形组。比较两组术前术后椎体前缘、中线、后缘高度变化，疼痛视觉模糊评分（VAS），手术时间，出血量等方面的差异。结果两组对椎体高度的恢复比较差异有统计学意义（P〈0．01），VAS、手术时间和出血量比较差异无统计学意义（P〉0．05）。结论经皮椎体成形术与椎体后凸成形术具有创伤小、手术时间短、出血量少等微创优点，而椎体后凸成形术具有较好的复位作用。     

Sandwich Vertebral Fracture in the Study of Adjacent-level Fracture After Vertebral Cement Augmentation

The literature is inconclusive on the development of adjacent-level vertebral fracture after initial cement augmentation. A preliminary hypotheses is that cement injection exaggerates force transmission to the adjacent vertebral bodies, thereby predisposing those levels to future fractures. A sandwich vertebra is an intact vertebral body located between 2 previously cemented vertebrae. The purpose of this study was to determine whether the risk of adjacent-level fracture increased due to load shift after a cement injection procedure. The authors retrospectively investigated the rate of adjacent-level fracture after sandwiching compared with conservative treatment and determined the potential causative factors of sandwich vertebral fracture. Age, sex, weight, height, body mass index, follow-up period, and location of sandwich level (T10-L2 or nonT10-L2 junction) were assessed. Surgical variables, including surgical procedure (vertebroplasty or balloon kyphoplasty), surgical approach (through uni- or bilateral pedicle), volume of cement injected into the painful vertebrae, cement leakage into the intervertebral disk, cumulative number of treated levels, and pre- and postoperative kyphotic angulation of the sandwich region, were also analyzed. Nine of 42 sandwiched levels developed fatigue fractures, whereas 11 of 71 patients treated with conservative therapy sustained new vertebral fractures adjacent to the treated levels. Only preoperative kyphotic angulation was the variable positively associated with sandwich vertebral fracture at follow-up (P=.021). Although subjected to double load shifts, the sandwich vertebra was not prone to structural failure. Thus, cement augmentation protocol does not increase the incidence of adjacent vertebral fracture.     

骨质疏松性椎体压缩骨折的微创治疗

骨质疏松性椎体压缩骨折常导致患者疼痛、活动受限，特别是随着老龄人群的增加，其发病率逐渐升高。传统采用保守治疗或者手术治疗效果不理想。近年采用椎体成形术(PVP)或后凸成形术(PKP)微创治疗骨质疏松性椎体压缩骨折，经皮穿刺椎体内注入骨水泥或先用球囊撑开压缩的椎体后再注入骨水泥进行椎体强化，可以达到稳定骨折、恢复椎体力学强度和缓解疼痛的目的=本文就有关这种微创治疗骨质疏松性椎体压缩骨折的最新进展加以综述。     

Vertebroplasty and Kyphoplasty in Spinal Trauma

Abstract Kyphoplasty and vertebroplasty have become recognized procedures for the treatment of vertebral fractures, especially in patients with osteoporosis. In most cases of osteoporotic spinal vertebral fracture in elderly patients, polymethylmethacrylate (PMMA) cement is used to fill the defect and stabilize the vertebral body. The techniques of vertebroplasty and kyphoplasty differ in the possibility of realignment and reconstruction of the vertebral body and spinal column. Long-term results in terms of integration of the cement and bioreactivity of the vertebral body are still lacking; so, these procedures are still no options in the treatment of younger patients. Vertebroplasty and kyphoplasty show different success in the management of fresh traumatic spine fractures. The acute traumatic vertebral fracture has to be classified sensitively, to find the right indication for cement augmentation. Mild acute compression fractures can be treated by vertebroplasty or kyphoplasty, severe compression and burst fractures by combination of internal fixation and kyphoplasty. The indications for use of biological or osteoinductive cement in spinal fracture management must still be regarded as restricted owing to the lack of basic biomechanical research data. Such cement should not be used except in clinical studies.     

椎体成形术与后凸成形术治疗老年陈旧性骨质疏松椎体压缩性骨折的相关问题探讨

目的:探讨椎体成形术(PVP)与后凸成形术(PKP)治疗老年陈旧性骨质疏松椎体压缩性骨折的疗效和安全性。方法:自2004年12月至2008年6月,采用PVP治疗28例(40椎)骨质疏松性椎体压缩性骨折,其中男11例(14椎),女17例(26椎);年龄70～91岁,平均72岁。骨折部位T5-L5。采用PKP治疗31例(43椎),男13例(18椎),女18例(25椎);年龄70～92岁,平均74岁;骨折部位T4-L5。术后采用疼痛视觉模拟评分(visualanaloguescale,VAS)、Oswestry功能评分、后凸Cobb角、椎体前中柱的平均高度及骨水泥的渗漏率等指标来评估两组疗效。结果:两组术后VAS评分和Oswestry功能评分都有明显下降,与术前相比有统计学差异(P0.01);两组间VAS评分和Oswestry功能评分降低值无统计学意义(P0.05)。两组后凸Cobb角及椎体前中柱的平均高度与术前比较差异无统计学意义(P0.05)。骨水泥渗漏率,PVP组3个椎体(7.5%),PKP组2个椎体(4.7%),但均无神经症状。两组比较差异无统计学意义(P0.05)。结论:PVP和PKP均能有效缓解老年陈旧性骨质疏松性椎体压缩性骨折所引起的疼痛,改善患者的脊柱功能,并且是一种安全有效的治疗方法。     

Evolution of bone mineral density after percutaneous kyphoplasty in fresh osteoporotic vertebral body fractures and adjacent vertebrae along with sagittal spine alignment

STUDY DESIGN: Prospective controlled cohort study of 27 adult osteoporotic patients who underwent kyphoplasty for fresh osteoporotic spinal fractures. OBJECTIVES: To define the evolution of vertebral bone mineral density (BMD) at kyphoplasty and adjacent levels along with sagittal spinal alignment to contribute to the etiology of adjacent vertebral fractures after augmentation. SUMMARY OF BACKGROUND DATA: Osteoporotic compression fractures can be effectively treated with methylmethacrylate vertebral augmentation. However, to the authors' knowledge the effect of vertebral augmentation on the vertebral endplate BMD of the augmented and adjacent nonaugmented levels has not as yet been described. METHODS: Twenty-seven consecutive selected patients (9 men, 18 women), with an average age of 72+/-9 years underwent 1, 2, or 3-level percutaneous kyphoplasty for painful fresh osteoporotic vertebral fractures at the thoracolumbar spine. All patients were radiologically examined with plain roentgenograms, computed tomography, and magnetic resonance imaging. Lateral dual energy x-ray absorptiometry in the augmented and on the adjacent vertebrae (1 level above and below kyphoplasty) was used to measure BMD preoperatively to the last postoperative observation in the subchondral bone of the vertebral endplates. Anthropometric data, sagittal global balance (plumbline), and segmental spine reconstruction (vertebral body height, Gardner kyphotic angle) were recorded and analyzed. The patients were followed for at least 2 years. RESULTS: Kyphoplasty was performed between T12 and L5. A total of 48 vertebral bodies were augmented. Thirteen patients received 1 level and the remaining 14 received 2 or 3-level kyphoplasty. No significant changes in the sagittal spinal balance were shown postoperatively. Gardner kyphotic angle and posterior vertebral body height improved postoperatively, however, insignificantly. Significant [analysis of variance (ANOVA), P=0.008] increase of anterior vertebral body height in the fractured vertebra was achieved postoperatively without subsequent loss of correction. BMD increased significantly in the lower endplate of the augmented vertebra (ANOVA, P=0.05). In 1-level augmentation, no BMD changes were shown at the adjacent vertebrae above and below kyphoplasty. On the contrary, in the multilevel augmentation, a statistically significant (ANOVA, P=0.05) decrease of the BMD was shown in the upper endplate of the adjacent level above kyphoplasty. During the 2-year follow-up, there were 5 (18%) new fractures at the T11-T12 area above the augmented vertebra. All of the fractures occurred in patients who received 2 and 3-level kyphoplasty. CONCLUSIONS: The observed 2-year evolution of vertebral endplate BMD, after kyphoplasty under stable global sagittal spinal balance, might contribute to the pathogenesis of new fractures in adjacent vertebra. However, other studies with control series and longer follow-up are necessary to show if these BMD changes are the result of vertebral augmentation or are merely natural history.     

A 3D finite element model of prophylactic vertebroplasty in the metastatic spine: Vertebral stability and stress distribution on adjacent vertebrae

Background and Objective: Patients with metastatically compromised vertebra can experience pathologic fracture with relevant neurological complications. Vertebroplasty is a low cost procedure and it can potentially prevent neurologic impairment if performed at an early stage. The aim of this study is to evaluate the effects of prophylactic vertebroplasty on stability of the metastatic spine and analyze load distribution at adjacent vertebrae.

Setting: A 3D finite element model of two spinal motion segments (L3-L5) was developed. A central core of elements was selected in L4 vertebral body and material properties of a lytic metastasis and successively PMMA were assigned. The model was settled in order to simulate a non-osteoporotic spine and an osteoporotic spine.

Outcome Measures: Vertebral stability was assessed by the measurement of vertebral bulge (VB) and vertebral height (VH) on L4. Load transfer on adjacent vertebrae was evaluated by observing the distribution of the von Mises stress on L3 and L5 endplates.

Results: The metastasis increased VB by 424% and VH by 626%, while prophylactic vertebroplasty decreased VB and VH by 99% and 95%, respectively, when compared to the normal/non-metastatic model. Prophylactic vertebroplasty increased the average von Mises stress of L3 lower endplate by 1.33% in the non-osteoporotic spine, while it increased to 16% in the osteoporotic model.

Conclusions: Prophylactic vertebroplasty could represent an interesting option to improve vertebral strength of metastatically compromised spine without excessively increasing the stresses on adjacent vertebrae in non-osteoporotic spine.     

骨填充网袋椎体成形术与经皮球囊后凸成形术治疗骨质疏松性椎体压缩性骨折

目的:探讨骨填充网袋椎体成形术治疗骨质疏松性椎体骨折的临床疗效。方法:对2015年12月至2017年6月符合纳入与排除标准的127例(145椎)骨质疏松性胸腰椎体骨折患者的临床资料进行回顾性分析,通过临床表现、X线、CT、MRI明确责任椎体,其中95例(110椎)采用经皮椎体后凸成形术治疗(PKP组),男34例(42椎),女61例(68椎),年龄(73.92±7.14)岁,胸椎47节(T_8-T_(12)),腰椎63节(L_1-L_5);另外的32例(35椎)采用骨填充网袋椎体成形术治疗(网袋组),男11例(12椎),女21例(23椎),年龄(71.56±7.89)岁,胸椎16节(T_9-T_(12)),腰椎19节(L_1-L_5)。观察患者术后3 d疼痛改善、椎体高度恢复、功能改善情况,并通过X线片观察骨水泥弥散及渗漏情况。结果:所有患者顺利完成手术,术中未出现并发症。骨填充网袋椎体成形术治疗的32例患者手术时间为(31.75±4.99)min,术后3 d的VAS评分,椎体前缘、中部高度,腰部ODI评分分别为(2.38±0.94)分、(19.54±2.36)mm、(18.16±2.65)mm和(25.19±5.49)分,各项目与术前比较明显改善(P0.01),与PKP组比较差异无统计学意义(P0.05)。术后3 d的X线片显示两组患者的骨水泥均呈斑片状、团块状或少量弥散状分布,网袋组的渗漏率为2.86%(1/35),PKP组的渗漏率为16.36%(18/110),多为"拖尾征",两组比较差异有统计学意义(P0.05)。结论:骨填充网袋椎体成形术治疗骨质疏松性椎体骨折具有类似经皮椎体后凸成形术的疗效,能够缓解疼痛,恢复部分椎体高度,并且明显减少渗漏率,是一种简单、快速、有效的治疗方法。     

Preliminary biomechanical evaluation of prophylactic vertebral reinforcement adjacent to vertebroplasty under cyclic loading

Background ContextPercutaneous vertebroplasty has become a favored treatment option for reducing pain in osteoporotic patients with vertebral compression fractures (VCFs). Short-term results are promising, although longer-term complications may arise from accelerated failure of the adjacent vertebral body.PurposeTo provide a preliminary biomechanical assessment of prophylactic vertebral reinforcement adjacent to vertebroplasty using a three-vertebra cadaveric segment under dynamic loads that represent increasing activity demands. In addition, the effects of reducing the elastic modulus of the cement used in the intact vertebrae were also assessed.Study Design/SettingThree-vertebra cadaveric segments were used to evaluate vertebroplasty with adjacent vertebral reinforcement as an intervention for VCFs.MethodsNine human three-vertebra segments (T12–L2) were prepared and a compression fracture was generated in the superior vertebrae. Vertebroplasty was performed on the fractured T12 vertebra. Subsequently, the adjacent intact L1 vertebra was prophylactically augmented with cement of differing elastic moduli (100–12.5% modulus of the base cement value). After subfailure quasi-static compression tests before and after augmentation, these specimens were subjected to an incrementally increasing dynamic load profile in proportion to patient body weight (BW) to assess the fatigue properties of the construct. Quantitative computed tomography assessments were conducted at several stages in the experimental process to evaluate the vertebral condition and quantify the gross dimensions of the segment.ResultsNo significant difference in construct stiffness was found pre– or postaugmentation (t=1.4, p=.19). Displacement plots recorded during dynamic loading showed little evidence of fracture under normal physiological loads or moderate activity (1–2.5× BW). A third of the specimens continued to endure increasing load demands and were confirmed to have no fracture after testing. In six specimens, however, greater loads induced 11 fractures: 7 in the augmented vertebra (2×T12, 5×L5) and 4 in the adjacent L2 vertebra. A strong correlation was observed between the subsidence in the segmental unit and the incidence of fracture after testing (r_Spearman's=?0.88, p=.002). Altering the modulus of cement in the intact vertebra had no effect on level of segmental compromise.ConclusionsThese preliminary findings suggest that under normal physiological loads associated with moderate physical activity, prophylactic augmentation adjacent to vertebroplasty showed little evidence of inducing fractures, although loads representing more strenuous activities may generate adjacent and peri-augmentation compromise. Reducing the elastic modulus of the cement in the adjacent intact vertebrae appeared to have no significant effect on the incidence or location of the induced fracture or the overall height loss of the vertebral segment.     

Stability of the metastatic spine pre and post vertebroplasty

OBJECTIVE: Vertebrae with lytic metastases have an elevated risk of burst fracture and resultant neurologic compromise. Prophylactic vertebroplasty has the potential to reduce pain and the risk of burst fracture in the metastatic spine. The purpose of this study was to quantify the ability of vertebroplasty to stabilize metastatically involved vertebrae against the risk of burst fracture initiation with a standardized model of vertebral metastases. METHODS: Metastases were simulated in eight fresh-frozen cadaveric thoracolumbar spinal motion segments by removing a central core of trabecular bone and filling the defect with tumor tissue. Specimens were tested under a physiologic level of axial compression, intact, with a simulated tumor and post-vertebroplasty, and ultimately tested to failure. Axial load induced canal narrowing (CN) was used as a measure of the risk of burst fracture initiation. Following testing, vertebrae were axially sectioned to visualize cement fill. RESULTS: Vertebrae with simulated metastases exhibited significantly higher CN than intact specimens (227%+/-109%; P<0.05). Post vertebroplasty, three vertebrae exhibited reduced CN compared with the simulated tumor configuration, whereas the other five had increased CN. Specimens with reduced CN were found to have cement posterior to the tumor, whereas specimens with an increase in CN had cement anterior and lateral to the tumor only. Percutaneous vertebroplasty is effective in decreasing CN if tumor is surrounded posteriorly with cement. However, injecting cement into the posterior third of the vertebral body is risky due to potential extravasation into the canal. CONCLUSION: Future work aimed at improving cement fill is necessary for safe and consistent stabilization of the metastatic spine with vertebroplasty.     

Minimally invasive treatment of osteoporotic vertebral body compression fractures.

BACKGROUND CONTEXT: Seven hundred thousand osteoporotic compression fractures occur yearly. Approximately 260,000 lead to severe pain, and 150,000 require hospital admissions. Associated with the fractures are increased loss of pulmonary function (90% decreased forced vital capacity per fracture level) and an increase in gastrointestinal complications (early satiety, and therefore malnutrition) and increased mortality (greater than that associated with osteoporotic hip fractures). New treatments available for these painful disorders include kyphoplasty and vertebroplasty. The injections of polymethylmethacrylate into the vertebrae (vertebroplasty technique) decrease pain and improve function. Kyphoplasty (percutaneous placement of a balloon tamp to improve height and create a void, and then the filling of this void with cement) improves function, decreases pain and helps realign the spine. PURPOSE: To compare kyphoplasty and vertebroplasty, and assess their various merits, treatment indications, and outcomes. STUDY DESIGN/SETTING: Literature review with presentation of early results of a national, clinical study. METHODS: Literature review for overview. Retrospective chart/patient review for clinical data presented on kyphoplasty. RESULTS: Ninety-five percent of individuals treated for painful osteoporotic compression fractures have significant improvement in symptoms and function after kyphoplasty or vertebroplasty. Kyphoplasty improves vertebral body height and kyphotic alignment by 50%, if performed within 3 months of the onset of the fracture collapse. CONCLUSIONS: Vertebroplasty and kyphoplasty both have roles in the treatment of painful osteoporotic compression fractures. Only kyphoplasty helps improve height and kyphosis, which should help prevent pulmonary and gastrointestinal complications.     

Preliminary results with modified techniques of balloon kyphoplasty for vertebra plana, traumatic fractures and neoplasms

Percutaneous vertebroplasty and balloon kyphoplasty are less invasive treatment options than open surgery for patients with vertebral compression fractures. With balloon kyphoplasty, the injection of bone cement is preceded by inflation and removal of bone tamps (balloons) inside the fractured vertebral body. This allows for the creation of a void, where viscous cement is delivered resulting in a lower risk for cement leakage than with vertebroplasty. Another advantage of the balloon inflation is the potential to correct the deformity and restore sagittal alignment. The percutaneous techniques normally require intact pedicles and intact posterior elements. We found that modifying the technique made it suitable for the management of vertebra plana, traumatic fractures, and neoplasms. Our study documents the different modified techniques and the clinical results obtained within the first 21 patients.     

Volumetric analysis of thoracic and lumbar vertebral bodies

Background contextDuring the last decade, vertebral augmentation techniques with cement (kyphoplasty and vertebroplasty) have revealed that 75% to 100% of individuals with osteoporotic vertebral compression fractures have good to moderate pain relief postoperatively, as well as adequate restoration of the vertebral body height. The volume of cement injected into a vertebra varied in different reports. To our knowledge, there are no studies that report on the physiological distribution of thoracic and lumbar vertebrae body volumes.PurposeThe purpose of this study was to quantitatively evaluate thoracic and lumbar vertebral body volumes.Study design/settingForty computed tomography (CT) scans of the thoracic and lumbar spines were used to measure a volume of each vertebral body.MethodsForty CT scans with standard 2.5-mm bone window cuts of the thoracic and lumbar vertebrae (20 men and 20 women) were analyzed to measure the volumetric capacity of vertebral bodies using a BrainLAB Software (iPlan RT image 4.0) program. The software was tested for validity and reliability in two pilot studies. Mean and standard deviations for each vertebral body volume were calculated and recorded. The vertebral body working distance and the so-called “safe zone” were also measured to determine a size of a balloon to be used in kyphoplasty.ResultsVertebral body volume increased gradually from T1 to L4 with the exception of L5, which measured to be smaller than L4. The mean thoracic vertebrae volume was 15.0 cm³ (ranged in the absolute values from 5.2 to 39.5 cm³), and the mean lumbar vertebrae volume was 35 cm³ (ranged in the absolute values from 19.7 to 61.5 cm³). Men had larger volume vertebral bodies only in the lumbar spine compared with women. The average vertebral body working distances from T1 to T4 was 23.4±2.7 mm, from T5 to T9 was 30.3±3.6 mm, and from T10 to L5 was 35.5±3.9 mm.ConclusionsKnowing the physiological variability of vertebral body volumes may help prevent complications as a result of underaugmentation or overaugmentation with excessive amount of cement during kyphoplasty or vertebroplasty in osteoporotic compression fractures. We recommend using 10 mm balloons from T1 to T4, 15 mm balloons from T5 to T9, and 20 mm balloons from T10 to L5 for kyphoplasty.     

Load shift of the intervertebral disc after a vertebroplasty: a finite-element study

Infiltrating osteoporotic cancellous bone with bone cement (vertebroplasty) is a novel surgical procedure to stabilize and prevent osteoporotic vertebral fractures. Short-term clinical and biomechanical results are encouraging; however, so far no reports on long-term results have been published. Our clinical observations suggest that vertebroplasty may induce subsequent fractures in the vertebrae adjacent to the ones augmented. At this point, there is only a limited understanding of what causes these fractures. We have previously hypothesized that adjacent fractures may result from a shift in stiffness and load following rigid augmentation. The purpose of this study is to determine the load shift in a lumbar motion segment following vertebroplasty. A finite-element (FE) model of a lumbar motion segment (L4-L5) was used to quantify and compare the pre- and post-augmentation stiffness and loading (load shift) of the intervertebral (IV) disc adjacent to the augmented vertebra in response to quasi-static compression. The results showed that the rigid cement augmentation underneath the endplates acted as an upright pillar that severely reduced the inward bulge of the endplates of the augmented vertebra. The bulge of the augmented endplate was reduced to 7% of its value before the augmentation, resulting in a stiffening of the IV joint by approximately 17%, and of the whole motion segment by approximately 11%. The IV pressure accordingly increased by approximately 19%, and the inward bulge of the endplate adjacent to the one augmented (L4 inferior) increased considerably, by approximately 17%. This increase of up to 17% in the inward bulge of the endplate adjacent to the one augmented may be the cause of the adjacent fractures.     

Refractures in cemented vertebrae after percutaneous vertebroplasty: a retrospective analysis

Percutaneous vertebroplasty is an efficient procedure to treat pain due to osteoporotic vertebral compression fractures. However, refracture of cemented vertebrae occurs occasionally after vertebroplasty. It is unclear whether such fractures are procedure-related or part of the natural course of osteoporosis. The effect of potentially important covariates on refracture risk in cemented vertebrae has not been evaluated previously. We retrospectively analyzed the incidence and possible causative mechanism of refracture in patients who had received only one vertebroplasty for a single level of vertebral compression fracture. We assessed the following covariates: age, sex, body weight, height, lumbar spine bone mineral density, treated vertebral level, pre-existing untreated vertebral compression fracture, and gas-containing vertebrae before treatment. Surgical variables, including surgical approach, cement injected, and anterior vertebral height restoration, were also analyzed. Anti-osteoporotic treatment after surgery was recorded. Multiple logistic regression analysis was used to determine the relative risk of refractures of cemented vertebrae. Over all, 98 patients were evaluated with a mean follow-up of 26.9 ± 12.4 months (range, 7–55 months). We identified 62 refractures and the mean loss of anterior vertebral height was 13.3% (range 3.2–40.3%). The greater the anterior vertebral height obtained from vertebroplasty, the greater the risk of refracture occurring (P < 0.01). Gas-containing vertebrae were also prone to refracture after the procedure (P = 0.01). Anti-osteoporotic treatment was of borderline significance between refractured and non-refractured vertebrae (P = 0.07). Only restoration of anterior vertebral height was positively associated with refracture during the follow-ups (P < 0.01). In conclusion, refractures of cemented vertebrae after vertebroplasty occurred in 63% of osteoporotic patients. Significant anterior vertebral height restoration increases the risk of subsequent fracture in cemented vertebrae.     

Lordoplasty: report on early results with a new technique for the treatment of vertebral compression fractures to restore the lordosis

Cement augmentation using PMMA cement is known as an efficient treatment for osteoporotic vertebral compression fractures with a rapid release of pain in most patients and prevention of an ongoing kyphotic deformity of the vertebrae treated. However, after a vertebroplasty there is no chance to restore vertebral height. Using the technique of kyphoplasty a certain restoration of vertebral body height can be achieved. But there is a limitation of recovery due to loss of correction when deflating the kyphoplastic ballon and before injecting the cement. In addition, the instruments used are quite expensive. Lordoplasty is another technique to restore kyphosis by indirect fracture reduction as it is used with an internal fixateur. The fractured and the adjacent vertebrae are instrumented with bone cannulas bipediculary and the adjacent vertebrae are augmentated with cement. After curing of the cement the fractured vertebra is reduced by applying a lordotic moment via the cannulas. While maintaining the pretension the fractured vertebra is reinforced. We performed a prospective trial of 26 patients with a lordoplastic procedure. There was a pain relief of about 87% and a significant decrease in VAS value from 7.3 to 1.9. Due to lordoplasty there was a significant and permanent correction in vertebral and segmental kyphotic angle about 15.2° and 10.0°, respectively and also a significant restoration in anterior and mid vertebral height. Lordoplasty is a minimal invasive technique to restore vertebral body height. An immediate relief of pain is achieved in most patients. The procedure is safe and cost effective.     

Biomechanics of vertebral compression fractures and clinical application

Local biomechanical factors in the etiology of vertebral compression fractures are reviewed. The vertebral body is particularly vulnerable to compression fracture when its bone mineral density (BMD) falls with age. However, the risk of fracture, and the type of fracture produced, does not depend simply on BMD. Equally important is the state of degeneration of the adjacent intervertebral discs, which largely determines how compressive forces are distributed over the vertebral body. Disc height also influences load-sharing between the vertebral body and neural arch, and hence by Wolff’s Law can influence regional variations in trabecular density within the vertebral body. Vertebral deformity is not entirely attributable to trauma: it can result from the gradual accumulation of fatigue damage, and can progress by a quasi-continuous process of “creep”. Cement injection techniques such as vertebroplasty and kyphoplasty are valuable in the treatment of these fractures. Both techniques can stiffen a fractured vertebral body, and kyphoplasty may contribute towards restoring its height. The presence of cement can limit endplate deformation, and thereby partially reverse the adverse changes in load-sharing which follow vertebral fracture. Cement also reduces time-dependent “creep” deformation of damaged vertebrae.     

椎弓根内固定结合椎体成形术治疗胸腰椎体转移瘤临床研究

[目的]观察椎弓根内固定术结合直视下椎体成形术治疗胸腰椎体转移性肿瘤的临床疗效.[方法]对30例胸腰椎转移性肿瘤的患者采用后路椎弓根内固定术结合直视下骨水泥椎体成形术,共治疗32个椎体,患者均有顽固性腰痛及下肢神经症状,部分患者行椎管减压.随访观察临床疗效.[结果]本组32个椎体全部穿刺成功,骨水泥渗漏3例,均未出现神经症状,患者术后1周,3、6、12个月各时间点VAS评分疼痛缓解率＞80％,活动能力和生活质量评分明显改善,随访12个月期间生存患者有24例,胸腰椎疼痛未见明显加重,病椎高度未见明显压缩,1例肺癌患者术后10个月出现肿瘤复发,其余患者手术椎体未出现新的病理性骨折及神经症状加重.[结论]椎弓根内固定结合椎体成形术治疗胸腰椎转移性恶性肿瘤能明显改善患者生存质量,预防病理性骨折进一步塌陷,疗效满意,是综合治疗胸腰椎肿瘤的重要治疗方法之一.