Biomechanical investigation of different internal fixations in medial opening-wedge high tibial osteotomy

BACKGROUND: The medial opening-wedge osteotomy for treatment of varus gonarthritis has become very popular in recent years. Different implants for internal fixation after the osteotomy have been created. It is still unclear, which principle of internal fixation (angle stable or non-angle-stable plate with or without spacer) has the best biomechanical properties. The aim of this study was to determine the biomechanical properties of different fixation techniques in medial opening-wedge high tibial osteotomy in a porcine bone model. METHODS: A 10-mm high tibial opening-wedge osteotomy was performed and stabilized with plates of similar dimensions but different functional principle (conventional plate, angle stable plate with or without spacer). Biomechanical properties (stiffness, displacement within the osteotomy space and load at failure) were evaluated under axial load. RESULTS: Plates which contain a spacer had a significantly higher stiffness at a load at 1000 N (p < 0.05). This correlates with a significantly reduced deformation within the osteotomy space. The strength at failure was not different between the groups. The use of a spacer in a conventional plate produces fractures of the lateral tibial cortex. In angle stable plates and plates containing spacers, the failure was caused by fractures of the lateral tibia surface, the fibula or by displacement within the tibio-fibular joint. The failure was caused primarily by implant insufficiency in plates without spacers. CONCLUSIONS: In a model with comparable conditions, implants which contain a spacer have superior biomechanical properties. Angle stable plates may prevent fractures of the lateral cortex after opening-wedge osteotomy.     

Die valgisierende proximale öffnende Tibiaosteotomie mit Plattenfixateur

In varus malalignment of the lower extremity the mechanical leg axis runs through the medial compartment of the knee joint. Varusarthrosis is considered as prearthritic deformity and leads to pain in the overloaded joint compartment. The aim of operative treatment is a lateral transfer of the weight bearing axis. The high tibial open wedge valgisation osteotomy allows correction of varus malalignment and leads to unloading of the medial compartment. Stabilization of the osteotomy is performed with an angular locking plate fixator (TomoFix?). This procedure guarantees a high biomechanical stability without secondary loss of correction.     

Biomechanical evaluation of different types of lateral hinge fractures in medial opening wedge high tibial osteotomy

BackgroundLateral hinge fractures are common complications in the medial opening wedge high tibial osteotomy for treatment of knee osteoarthritis. The rehabilitation protocols are decided depending on the remaining stability following these fractures. This study aimed to evaluate the biomechanical properties of different types of lateral hinge fractures in medial opening wedge high tibial osteotomy.MethodsTwenty synthetic tibia models were used as test samples. A 10-mm bone wedge was removed from the medial side of the proximal tibias to create the bone defect. The samples were then divided into 4 groups: (1) intact lateral hinge; (2) Takeuchi type I fractures; (3) type II fractures; and (4) type III fractures. After fixation with a locking plate, the stability parameters including construct stiffness, wedge displacement, and construct strength were tested under compressive forces and compared among the 4 groups.FindingsNo statistical difference was found in the construct stiffness among the 4 groups (P = 0.78). The type III fractures had the largest wedge displacement compared with the other 3 groups. The failure loads on average were significantly reduced in the type III fractures compared with those with intact hinge (P < 0.01) and in type I fractures (P = 0.04). No statistical difference was observed between the type I fractures and the intact hinge in terms of wedge displacement or failure loads.InterpretationThe type III fractures were the most unstable and patients with these fractures should be managed cautiously. Delayed weightbearing and/or additional fixation should be considered.     

Biomechanical stability of high tibial opening wedge osteotomy: internal fixation versus external fixation

PURPOSE. The goal of our study was to evaluate stability of internal fixation with a plate compared to external fixation in an opening wedge high tibial osteotomy model. Significance. To our knowledge, this is the only study to compare internal plate to external fixation in an opening wedge osteotomy model. The design of this cadaver study limits its direct application to clinical practice. MATERIAL AND METHOD. In each of the six pairs of fresh-frozen human cadaver knees one specimen was randomly assigned to internal plate fixation while the other was stabilized with an external fixation. The osteosynthesis plate incorporated a 12.5mm block that distracted the medial tibial cortices. Each knee was loaded on a mechanical testing machine to 700 N for 10,000 cycles to simulate immediate full weight bearing in a walking individual. SUMMARY OF RESULTS. The internal plate osteosynthesis provided significantly greater stiffness and smaller loss of correction (1.60mm) than the external fixation (3.22 mm) under cyclic loading condition (P<0.05). For static loading, the mean value of stiffness resulting in failure for the internal plate and external fixation, were respectively, 938 N/mm and 459 N/mm. Load to failure also showed two times greater stiffness in the plate osteosynthesis group. No hardware failure was observed in either construct. DISCUSSION AND CONCLUSION. Plate fixation was superior to external fixation in maintaining correction. However, progressive adjustment of the distraction with the external fixator allows precise "fine-tuning" during the healing process that is not possible with internal fixation.     

Optimal configuration of a dual locking plate for femoral allograft or recycled autograft bone fixation: A finite element and biomechanical analysis

BackgroundAllografts and recycled bone autograft are commonly used for biological reconstruction. The dual locking plates fixation method has been advocated for increasing allograft stability and preventing fixation failure; however, the biomechanical properties of the various configurations of dual locking plates have not been extensively studied.MethodsIn a finite element (FE) analysis, we developed 6 patterns of different dual locking plate configurations for fixation of the mid shaft of the femur. The maximum strains were recorded for each of the 6 models then axial, bending and torsion stiffness were calculated. The FE analysis was validated the results with mechanical testing (axial compression, bending, and torsional stiffness) on a cadaveric femur.FindingsThe highest axial compression (715.41 N/mm) and lateral bending (2981.24 N/mm) was found in Model 4 (with two 10-hole locking plates placed at the medial and lateral side), while the highest torsional stiffness (193.59 N·mm /mm) was found in Model 3 (with 8- and 10-hole locking plates placed at the posterior and lateral side). Excellent agreement was found between the finite element analysis and biomechanical testing (r² = 0.98).InterpretationThe dual locking plate configuration with medial and lateral, 10-hole locking plates provided the most rigid and strongest fixation of the femur; both in terms of axial compression and lateral bending stiffness.     

Tension band wire fixation for valgus osteotomies of the proximal femur: a biomechanical study of three configurations of fixation

BACKGROUND: A variety of techniques can be used to achieve stabilization of femoral valgus osteotomies in children, but what is lacking is a versatile fixation system that associates stability and versatility at different ages and for different degrees of deformity. METHODS: Mechanical tests of three configurations used to fix femoral valgus osteotomies, based on the tension band wire principle, were carried out. A 30 degrees wedge valgus osteotomy was performed at the subtrochanteric level in 60 swine femurs and fixed with three different systems. In Group 1, two Kirschner wires (K wire) were introduced from the tip of the greater trochanter to the medial cortex, crossing the osteotomy. A flexible steel wire was anchored to the K wires into holes in the lateral cortex and tightened to form a tension band. The same setup was used in Group 2, but two additional smooth K wires were inserted into the lateral surface of the greater trochanter and driven to the femoral head with the distal extremities bent and tied around the bone shaft. In Group 3, the fixation was similar to that in Group 2, but the ascending K wires were introduced below the osteotomy level, crossing the osteotomy. Mechanical tests in bending-compression and torsion were used to access the stability. FINDINGS: The torsional relative stiffness was 116% greater for Group 3 (0.27 Nm/degree) and no significant difference was found between Group 1 (0.10Nm/degree) and Group 2 (0.12 Nm/degree). The average torque was 103% higher for Group 3 (1.86 Nm). Stiffness in bending-compression was significantly higher in Group 3 (508 x 10(3) N/m) than in Group 1 (211 x 10(3) N/m) and Group 2 (219 x 10(3) N/m). INTERPRETATION: Fixation as used in Group 3 was significantly more stable, both in torsion and bending-compression tests, than the other two techniques.     

Open-wedge-Osteotomie: Konzept und erste Erfahrungen

Valgus high tibial osteotomy is an established treatment for medial osteoarthritis in the varus knee. The classic technique involves removal of a laterally based bone wedge from the tibia (closed wedge), fibula osteotomy and osteosynthesis of the tibia by a lateral exposure. This procedure has a certain risk potential regarding peroneal nerve injuries, instability of the osteotomy and secondary loss of correction. Opening wedge technique from medially avoids muscle detachment, dissection of the peroneal nerve, proximal fibula osteotomy and leg shortening. Only one osteotomy must be performed and the correction can be adapted intraoperatively. The posterior tibial slope can be adjusted as needed. A new specifically designed plate fixator inserted percutaneously allows stable fixation of the osteotomy. The use of bone grafts or bone substitutes can be avoided in most cases. 349 patients were treated with this technique. The mean opening of the osteotomies was 11,6 mm. Complications included 4 non-unions which required secondary bone grafting. However there were no implant failures nor any case of loss of correction. Hight tibial valgus osteotomy in opening wedge technique as shown above is a very safe and effective treatment method with minimal morbidity.     

Synovial chondromatosis originating from the synovium of the anterior cruciate ligament: a case report

A 40 year old welder who underwent opening-wedge high tibial osteotomy for correction of alignment in a varus knee developed persistent pain with loss of knee extension. The posterior tibial slope increased from 9 degrees to 20 degrees after the osteotomy and caused the anteromedial knee pain and limited extension. The patient then underwent a revision osteotomy using a closing wedge technique to correct tibial slope. The osteotomy was performed, first from the medial cortex in the lateral direction, and second in the anteroposterior direction to remove the tibial bone in wedge shape and obtain full extension of the knee. The posterior tibial slope decreased to 8 degrees after the revision osteotomy and the patients returned to pain-free daily life. We reviewed this unique technique for correction of sagittal malalignment using a closing-wedge osteotomy for revision after opening-wedge osteotomy.     

Tibiavalgisationsosteotomie: Lateral zuklappend vs. medial aufklappend

High tibial osteotomy is an effective method to treat medial osteoarthritis of the knee. A proper indication is therefore most important for successful surgery. However, others than the final outcome for the patient operated on should not guide the choice of technique used. All surgical techniques need high precision to realize the planned correction and to avoid complications. We have seen that both techniques used in our hospital provide a good and effective way to perform a high tibial osteotomy. Especially in regards to frontal plane alignment we see a high stability with an overcorrection in closed wedge osteotomy and a loss of correction in open wedge osteotomy of less than 1°. However, we have seen a significant change in posterior tibial slope in open wedge osteotomies in the technique described by Puddu which could affect the knee kinematics dramatically (other open wedge techniques might avoid this however). The closing wedge osteotomy using the technique as described by Müller showed only minor changes of the sagittal plane of the tibia. Therefore if utilizing a closed wedge osteotomy we recommend this technique.     

Role of the fibula in the stability of diaphyseal tibial fractures fixed by intramedullary nailing

BackgroundFor tibial fractures, the decision to fix a concomitant fibular fracture is undertaken on a case-by-case basis. To aid in this clinical decision-making process, we investigated whether loss of integrity of the fibula significantly destabilises midshaft tibial fractures, whether fixation of the fibula restores stability to the tibia, and whether removal of the fibula and interosseous membrane for expediency in biomechanical testing significantly influences tibial interfragmentary mechanics.MethodsTibia/fibula pairs were harvested from six cadaveric donors with the interosseous membrane intact. A tibial osteotomy fracture was fixed by reamed intramedullary (IM) nailing. Axial, torsion, bending, and shear tests were completed for four models of fibular involvement: intact fibula, osteotomy fracture, fibular plating, and resected fibula and interosseous membrane.FindingsOverall construct stiffness decreased slightly with fibular osteotomy compared to intact bone, but this change was not statistically significant. Under low loads, the influence of the fibula on construct stability was only statistically significant in torsion (large effect size). Fibular plating stiffened the construct slightly, but this change was not statistically significant compared to the fibular osteotomy case. Complete resection of the fibula and interosseous membrane significantly decreased construct torsional stiffness only (large effect size).InterpretationThese results suggest that fixation of the fibula may not contribute significantly to the stability of diaphyseal tibial fractures and should not be undertaken unless otherwise clinically indicated. For testing purposes, load-sharing through the interosseous membrane contributes significantly to overall construct mechanics, especially in torsion, and we recommend preservation of these structures when possible.     

内外侧锁定钢板固定胫骨远端骨折的比较

背景：随着胫骨远端骨折发生率的增加,锁定钢板内固定已成为首选的内固定治疗方法。目的：研究分析胫骨远端骨折内固定的生物力学性能,同时比较内侧锁定钢板与外侧锁定钢板内固定治疗胫骨远端骨折的差异。方法：应用文献检索的方法获取胫骨远端骨折内固定生物力学的相关研究文献,对符合研究标准的文献进行深入的数据分析,文章选取胫骨远端骨折时踝关节的应力分布机制以及锁定钢板与髓内钉内固定的生物力学性能进行比较,同时比较上海交通大学医学院附属新华医院崇明分院骨科2009年1月至2012年1月收治的60例胫骨远端骨折患者应用内侧锁定钢板内固定和外锁定钢板内固定治疗的效果。结果与结论：胫骨远端骨折,足处于跖屈位时,易引起胫骨后踝骨折;中立位时,易引起Y型骨折;背屈位时,易引起胫骨前缘压缩。锁定钢板在抗扭转外力上比髓内钉效果要好,且腓骨的完整对于2种固定的效果均有一定的帮助。当腓骨不能够有效固定的时候,锁定钢板固定的稳定性比髓内钉固定的稳定性更好。且内侧锁定钢板固定与外侧锁定钢板固定时的骨折愈合时间并无明显差异,但是外侧锁定钢板固定的并发症发生率更低,踝关节功能恢复更好。     

Biomechanical comparison of two different periarticular plating systems for stabilization of complex distal humerus fractures

BACKGROUND: Complex intra-articular distal humerus fractures are relatively uncommon injuries but are fraught with poor outcomes such as malunion, elbow stiffness and deformity. Various types of internal fixation screw-plate constructs have been developed to improve fixation. Specifically, a 90 degrees offset periarticular system lowers the profile on the lateral epicondyle, yet it is unclear how this design compares to other plate constructs. This study compared the mechanical stiffness and plate surface strains between two types of constructs for stabilization of complex distal humerus fractures. METHODS: Identical bi-columnar segmental intra-articular fractures were created in ten epoxy composite left humeri. Models were randomly assigned to two groups (n=5/group) with either parallel plates or perpendicular plates. Rosette strain gages were placed at the most distal possible space on the lateral plate for both constructs. Models were mechanically tested with estimates of physiologic loads in flexion, extension, varus, valgus axial compression and axial torsion. Data for mechanical stiffness, transverse plate strain and longitudinal plate strain were compared with a one-way ANOVA (P<0.05). FINDINGS: There was no statistical difference in stiffness in any direction. The longitudinal strain for the 90 degrees construct was significantly lower in axial compression. The 180 degrees system demonstrated significantly lower transverse strains during axial torsion. INTERPRETATION: Both systems demonstrated similar mechanical stiffness theoretically providing similar fracture stabilization. Plate strain differences may affect fragment position, but it is unclear how much plate loading occurs in vivo. Surgeon experience and preference may dictate the choice of a plate construct for this fracture configuration.     

Adding a protective screw improves hinge's axial and torsional stability in High Tibial Osteotomy

BackgroundsDespite the use of a locking plate a 30% incidence of lateral hinge fracture after Open-Wedge High Tibial Ostetomy was described in the literature.A finite element model was used to analyze if the presence of a hinge-securing screw in the osteotomy area, using Patient Specific Cutting Guides with a locking plate, decreases the stresses within the lateral hinge during compression and torsion.MethodsA 3D model of a tibial sawbone was used to simulate an opening wedge of 10°. To apply loads on the tibial plateau, two supports were modelled on each tibial plateau to simulate the femoral condyles forces. A two second model with a hinge-stabilizing was defined with two different screws (diameter 2 mm and 4 mm). Two cases of static charges were considered 1) compression test (2500 N) 2) Torsion test (along the tibial mechanical axis).FindingsDuring compression simulation, 17% of the total surface of lateral hinge was stressed between 41-50Mpa without hinge-securing screw while the amount of surface under stress between 41 and 50 MPa dropped significantly under screw stabilization (1% for the 2 mm and 3% for the 4 mm).During torsion stress simulation a decrease of the value of the maximal stress in the lateral hinge was also observed with the addition of a hinge-securing screw (37 MPa without screw, 27Mpa with a 2 mm screw and 25 Mpa with a 4 mm screw).InterpretationPositioning a screw intersecting the cutting plane at the theoretical lateral hinge location associated with a locking plate reduces lateral hinge stress in both compression and torsion. Those findings need to be confirmed by further specimens' mechanical testing.     

自制微创股骨近端接骨板与普通动力髋螺钉治疗稳定型股骨转子间骨折的生物力学对比

背景:研制一种新型植入物用于固定稳定型股骨转子间骨折。目的:比较自制微创股骨近端系列接骨板与动力髋螺钉固定稳定型股骨转子间骨折后的生物力学性能。方法:采集干燥股骨标本,模拟AO分型A1.3型稳定型股骨转子间骨折模型,分别采用自制微创股骨近端系列接骨板和动力髋螺钉内固定,然后在股骨近端内外侧皮质布置6枚电阻片,检测固定后的抗压、抗弯、抗剪和抗扭能力。结果与结论:股骨转子间骨折采用自制微创股骨近端系列接骨板固定后,股骨内、外侧强度比动力髋螺钉组固定强度高13%,内侧强度高16%,扭转强度高18%,扭转刚度高31%,差异有显著性意义(P<0.05)。可见自制微创股骨近端系列接骨板整体生物力学性能优于常规用动力髋螺钉,前者能十分有效对抗股骨抗拉、抗压、抗旋和内翻能力。     

Effect of tibial re-alignment surgery on single leg standing balance in patients with knee osteoarthritis

Background

Standing balance is impaired in individuals with knee osteoarthritis and is associated with disease severity. The effects of surgical interventions on standing balance have received little attention. The purpose of the present study was to examine measures of balance during tests of single-limb standing before and after medial opening wedge high tibial osteotomy – a lower limb re-alignment procedure for those with varus alignment and knee osteoarthritis.

Methods

Standing balance was assessed in 49 individuals prior to and 12 months following medial opening wedge high tibial osteotomy. Participants performed three trials of single-limb balance lasting 10 s each while standing on a force platform. Anteroposterior and mediolateral coordinates of the centre of pressure were obtained from the force platform and used to calculate the total centre of pressure path length as well as the range and variability (standard deviation) of the anteroposterior and mediolateral coordinates.

Findings

Though all centre of pressure measures were lower following high tibial osteotomy, none reached statistical significance (P > 0.05) and effect sizes were small (d < 0.34). The largest mean improvement was 7.6% (95% confidence interval: −0.7–15.8%).

Interpretation

Results indicate that standing balance in individuals with knee osteoarthritis is not significantly different following high tibial osteotomy surgery. Standing balance in this patient population is a complex process not entirely dictated by disease symptoms or structural factors such as alignment.     

双板固定股骨远端粉碎性骨折的生物力学研究

INTRODUCTIONComminutedfractureofdistalfemurbelongstoseverehigh-energyinjuries.Therapeuticeffectisnotsatisfying犤1-3犦.Inthisstudy,bonefractureplatemadefromhigh-densitypolytheneplatewasusedtofixthefractureontheoneside,andlateralsteelplateontheotherside.MATERIALSANDMETHODSMaterials10specimenoffemurfromfreshadultcorpuswereprovidedbyTheDepartmentofHumanAnatomy.Softtissue,andtheupper1/3offemurwereremoved.Internalfixationinstruments8-wellsteelplateoftitaniumalloy(16cm×2.2cm×0.25cm),…     

The effect of wedge and tibial slope angles on knee contact pressure and kinematics following medial opening-wedge high tibial osteotomy

BackgroundHigh tibial osteotomy is a surgical procedure to treat medial compartment osteoarthritis in varus knees. The reported success rates of the procedure are inconsistent, which may be due to sagittal plane alignment of the osteotomy. The objective of this study was to determine the effect of changing tibial slope, for a range of tibial wedge angles in high tibial osteotomy, on knee joint contact pressure location and kinematics during continuous loaded flexion/extension.MethodsSeven cadaveric knee specimens were cycled through flexion and extension in an Oxford knee-loading rig. The osteotomy on each specimen was adjusted to seven clinically relevant wedge and slope combinations. We used pressure sensors to determine the position of the centre of pressure in each compartment of the tibial plateau and infrared motion capture markers to determine tibiofemoral and patellofemoral kinematics.FindingsIn early knee flexion, a 5° increase in tibial slope shifted the centre of pressure in the medial compartment anteriorly by 4.5 mm (P ≤ 0.001), (from the neutral slope/wedge position). Increasing the tibial slope also resulted in the tibia translating anteriorly (P ≤ 0.001).InterpretationChanges to the tibial slope during high tibial osteotomy for all tested wedge angles shifted the centre of pressure in both the medial and lateral compartments substantially and altered knee kinematics. Tibial slope should be controlled during high tibial osteotomy to prevent unwanted changes in tibial plateau contact loads.     

新型儿童股骨颈螺钉设计中的生物力学因素

背景：由于骺板在股骨的生长发育过程中有重要的作用,内固定的设计要求尽量避免对骺板的损伤,因此对儿童股骨骺板的定位显得尤其重要。 目的：探讨新型儿童股骨颈螺钉固定儿童股骨颈骨折的生物力学性能。 方法：由南华大学解剖室提供的6具儿童尸体上取下股骨12根,X射线排除骨病后,分别采用3枚新型儿童股骨颈螺钉固定;3枚2.0 mm克氏针固定。分别进行生物力学实验,测试其轴向压缩、扭转刚度。 结果与结论：轴向压缩刚度及最大3 N·m 的扭转力矩下扭转刚度,儿童股骨颈螺钉分别为（190.74±20.88） N/mm、（0.18±0.045） N·m/（°）,克氏针为（138.95±15.19） N/mm、（0.120±0.036） N·m/（°）,两者比较差异均有显著性意义（P〈0.05）;显示儿童股骨颈螺钉的抗压能力和抗扭能力上明显强于克氏针。实验说明儿童股骨颈螺钉是一种符合儿童股骨近端解剖学特点,能够满足儿童股骨颈骨折需要的新型内固定器械,具有良好的生物力学性能。     

3D打印个体化截骨导板辅助胫骨高位截骨术治疗内翻型膝骨关节炎精准性的临床疗效

目的:观察3D打印个体化截骨导板(patient-specific instrumentation, PSI)辅助胫骨高位截骨术(high tibial osteotomy, HTO)治疗内翻型膝骨关节炎的精准性。方法:2018年5月至2020年12月采用3D打印PSI辅助内侧开放胫骨高位截骨术治疗15例膝内翻畸形合并骨性关节炎患者,通过术前CT三维重建模拟规划截骨手术时的胫骨近端内侧角(medial proximal tibial angle, MPTA)、下肢负重线比率(weight bearing line, WBL)落点、撑开高度、胫骨后倾角(posterior tibial slope, PTS)、关节线交角(joint line convergence angle, JLCA),并与截骨术后实际测量值进行比较。结果:术前规划与术后测量的MPTA、WBL落点、撑开高度、PTS及JLCA之间差异均无统计学意义,一致性良好。所有患者伤口均Ⅰ期愈合,无并发症。结论:3D打印PSI辅助胫骨高位截骨术能够增加下肢力线矫正的精准性,降低PTS、JLCA等变化的风险,提高疗效。     

经皮穿刺斜入路置入单枚膨胀式腰椎间融合器的生物力学试验

背景:各种椎间融合器(cage)已相继被用于腰椎椎间融合,其力学性能良好,临床效果满意.常规的后路融合要平行置入双枚cage,但有学者提出可以斜向置入单枚cage的方法.目的:实验设计方案特点在于将膨胀式cage和斜向置入单枚cage的方法相结合,通过人体外的生物力学试验,以得到一种在临床上能满足治疗要求而创伤更小的方法.设计、时间及地点:随机抽样对照实验,于2005-05/2008-05在上海生物力学工程研究所完成.材料:可膨胀式椎间融合器采用仿制的以色列Disc-O-Tech公司生产的B-Twin Cage.小牛新鲜腰椎标本自购自备.方法:用18具小牛腰椎运动功能单位进行生物力学试验,分为3组,对照组、单枚斜向组及双枚平行组各6个.先测试对照组完整标本力学性能而后分组置入进行力学试验.采用WE-10A液压万能试验机,对标本进行轴向中心压缩、前屈、后伸、左右侧屈以及扭转刚度试验.主要观察指标:各组标本的轴向刚度及扭转刚度结果.结果:双枚cage置入组比单枚cage置入组的轴向刚度高,但只有轴向中心压缩和后伸运动方向的差异有显著性意义,扭转刚度单枚cage置入组较双枚cage置入组高(P＜0.15.结论:经皮穿刺斜入路放置单枚膨胀式椎间融合器进行椎间骨融合从理论上是可行的;置入膨胀式融合器的腰椎功能单元的生物力学稳定性能增强,其楔形形状有一定作用;与经侧后路斜向置入单枚cage相比,经后路平行置入双枚cage的轴向稳定性高,但扭转稳定性低.