Significant Range Of Motion Reduction Research Articles

The study on the relationship between venous ulcer and ankle joint range of motion using ultrasound.

Chronic venous insufficiency (CVI) often leads to venous ulcers. The relationship between ankle joint range of motion (ROM) and venous ulcers remains under-investigated. This study aims to clarify this relationship using ultrasound imaging. We conducted a study on 20 patients with unilateral venous ulcers. Ankle ROM and popliteal vein blood flow were measured using a goniometer and ultrasound, respectively. The measurements were compared between the affected and unaffected limbs. A significant reduction in ROM and popliteal vein blood flow was observed in the limbs with venous ulcers compared to the unaffected limbs. The data suggest a correlation between reduced ankle mobility and the development of venous ulcers. The study underscores the importance of maintaining ankle mobility in patients with CVI to prevent venous ulcers. A multifactorial approach is essential for managing these conditions effectively.

Preliminary Results of a Prospective Clinical and Radiological Study with Roentgen Stereophotogrammetric Analysis (RSA) after Implantation of a Posterior Dynamic Stabilization Device in the Lumbar Spine

Introduction: Posterior dynamic stabilization (PDS) can be based on interspinous distraction devices (IDD). The goals of these implants are maintaining or restoring intervertebral range of motion (ROM) in a controlled fashion and avoiding a complete restriction of mobility. Clinical and radiological data with the Wallis® spacer as one type of IDD have been rarely reported. The goal of this study was to present clinical and radiological data including roentgen stereophotogrammetric analysis (RSA) after a short- to mid-term follow-up period.
 Patients and Methods: 10 patients were included in this prospective monocentric study and had PDS of the lumbar spine with an IDD (Wallis® spacer). Before and soon after operation and 3, 6, and 12 months later clinical and radiological evaluations were performed. Pain and disability were analyzed by use of visual analog scale for back and leg pain, Oswestry Disability Index, Roland-Morris Disability Questionnaire and Short-Form-36 Health Survey. The ROM of the operated levels and the total lumbar spine was determined by use of lateral functional x-ray images with calculation of the differences of the segmental and total lumbar spine angles in flexion and extension. Furthermore, RSA was used to measure the segmental ROM.
 Results: After a follow-up of 12 months, the results of the pain intensity and the disability and health related quality of life scores showed statistical significant improvement. The segmental angles of the operated levels demonstrated statistical significant reduction in ROM during the different follow-up examinations. The discrepancy of the conventionally determined segmental angles and the data measured by RSA were low with a mean of 1.77°. The mean total lumbar spine angles did not change statistically significantly during the postoperative controls.
 Conclusions: According to the radiological results of this study, the used implant leads to a posterior dynamic stabilization. The clinical findings are promising, but they are to be interpreted with caution because of the small number of patients and the lack of a control group.

Biomechanical evaluation of strategies for adjacent segment disease after lateral lumbar interbody fusion: is the extension of pedicle screws necessary?

BackgroundAdjacent segment disease (ASD) is a well-known complication after interbody fusion. Pedicle screw-rod revision possesses sufficient strength and rigidity. However, is a surgical segment with rigid fixation necessary for ASD reoperation? This study aimed to investigate the biomechanical effect of different instrumentation on lateral lumbar interbody fusion (LLIF) for ASD treatment.MethodsA validated L2~5 finite element (FE) model was modified for simulation. ASD was considered the level cranial to the upper-instrumented segment (L3/4). Bone graft fusion in LLIF with bilateral pedicle screw (BPS) fixation occurred at L4/5. The ASD segment for each group underwent a) LLIF + posterior extension of BPS, b) PLIF + posterior extension of BPS, c) LLIF + lateral screw, and d) stand-alone LLIF. The L3/4 range of motion (ROM), interbody cage stress and strain, screw-bone interface stress, cage-endplate interface stress, and L2/3 nucleus pulposus of intradiscal pressure (NP-IDP) analysis were calculated for comparisons among the four models.ResultsAll reconstructive models displayed decreased motion at L3/4. Under each loading condition, the difference was not significant between models a and b, which provided the maximum ROM reduction (73.8 to 97.7% and 68.3 to 98.4%, respectively). Model c also provided a significant ROM reduction (64.9 to 77.5%). Model d provided a minimal restriction of the ROM (18.3 to 90.1%), which exceeded that of model a by 13.1 times for flexion-extension, 10.3 times for lateral bending and 4.8 times for rotation. Model b generated greater cage stress than other models, particularly for flexion. The maximum displacement of the cage and the peak stress of the cage-endplate interface were found to be the highest in model d under all loading conditions. For the screw-bone interface, the stress was much greater with lateral instrumentation than with posterior instrumentation.ConclusionsStand-alone LLIF is likely to have limited stability, particularly for lateral bending and axial rotation. Posterior extension of BPS can provide reliable stability and excellent protective effects on instrumentation and endplates. However, LLIF with the use of an in situ screw may be an alternative for ASD reoperation.

Effects of the ACTN3 R577X Genotype on the Muscular Strength and Range of Motion Before and After Eccentric Contractions of the Elbow Flexors.

The purpose of present study was to examine the association between ACTN3 R577X genotype and functional characteristics of elbow flexors before and after isokinetic eccentric contractions (ECCs). Fifty-two men (age: 20.8±3.8 years, height: 172.5±5.9 cm, body mass: 64.7±6.5 kg, BMI: 21.7±1.7) who had not participated in any regular resistance training for at least 1 year prior to this study were recruited. ECCs consisted of five sets of six maximal voluntary isokinetic (30°/s) ECCs of the elbow flexors with a range of motion (ROM) from 90° flexion to 0° (full extension). Measurements of maximal voluntary isometric contraction (MVC) torque, ROM, and muscle soreness were taken before, immediately after, and 1, 2, 3, and 5 days after ECCs. Genotyping results were analyzed for identifying ACTN3 R577X polymorphism (rs1815739) using TaqMan approach. The genotype frequencies of the ACTN3 R577X polymorphism were RR 26.9% (n=14), RX 50.0% (n=26), and XX 23.1% (n=12). There were no significant differences in MVC torque, ROM, and soreness between three genotype groups of ACTN3 R577X. However, MVC at baseline was greater in RR homozygotes than in X-allele carriers (combined XX and RX; p<0.05). ROM in RR homozygotes at baseline was lower than that of X-allele carriers. Although a significant decrease in ROM was observed in X-allele carriers until 3 days after ECCs, a significant ROM reduction in RR homozygotes was observed only immediately after ECCs. Our data indicated that ACTN3 RR genotype has higher MVC and lower flexibility than X-allele carriers at baseline, but the effect of ACTN3 R577X genotype on these two parameters is limited after ECCs.

Cement-augmented screws in a cervical two-level corpectomy with anterior titanium mesh cage reconstruction: a biomechanical study.

Biomechanical investigation. Cervical two-level corpectomies with anterior-only instrumentation are associated with a high rate of implant-related complications. These procedures, therefore, often require an additional dorsal instrumentation to prevent screw loosening. Cement augmentation of the anterior screws in two-level corpectomies might stabilize the construct, so that a second dorsal procedure could be avoided. To evaluate the screw anchorage in cervical anterior-only procedures, an ex vivo evaluation of the range of motion (ROM) in two-level corpectomies (C4 and C5), with and without cement augmentation of the anterior screws, was carried out in this study. Twelve human cervical cadaveric spines (C2-T1) were divided into two groups of six specimens each. Corpectomies were performed in C4 and C5, with grafting and anterior instrumentation with and without cement augmentation of the anterior screw-and-plate system (0.3-0.5mL cement/screw). Flexibility tests with pure moments (1.5Nm) were carried out before and after three cyclic loading periods of 5000 cycles with increasing eccentric forces (100, 200, and 300N). After corpectomy and instrumentation, the control group and the augmented group showed a significant reduction in ROM in comparison with the native states with average ROMs of 49% (±17%) and 24% (±10%), respectively (P=0.006). The ROM in the control group increased significantly in all motion directions in the course of cyclic loading and approached native values after the third cyclic loading period, with an overall ROM of 78% (±22%). In contrast, the augmented group maintained a significantly decreased ROM in all motion directions during cyclic loading, with a final ROM of 32% (±14%) after the third period of cyclic testing. Inter-group comparison demonstrated a significant difference between the two groups in the course of cyclic loading. The cement-augmented group outperformed the control group in all motion directions, with a significantly lower ROM after all three cyclic loading periods. A two-level corpectomy with cement-augmentation results in a significantly reduced ROM. In comparison with the conventional anterior screw-and-plate fixation, it represents a significantly stabilized two-level anterior construct. This might be a treatment option for patients with a two-level corpectomy associated with reduced bone mineral density, to avoid an additional dorsal instrumentation.

Biomechanical testing of circumferential instrumentation after cervical multilevel corpectomy.

Biomechanical investigation. This study describes ex vivo evaluation of the range of motion (ROM) to characterize the stability and need for additional dorsal fixation after cervical single-level, two-level or multilevel corpectomy (CE) to elucidate biomechanical differences between anterior-only and supplemental dorsal instrumentation. Twelve human cervical cadaveric spines were loaded in a spine tester with pure moments of 1.5 Nm in lateral bending (LB), flexion/extension (FE), and axial rotation (AR), followed by two cyclic loading periods for three-level corpectomies. After each cyclic loading session, flexibility tests were performed for anterior-only instrumentation (group_1, six specimens) and circumferential instrumentation (group_2, six specimens). The flexibility tests for all circumferential instrumentations showed a significant decrease in ROM in comparison with the intact state and anterior-only instrumentations. In comparison with the intact state, supplemental dorsal instrumentation after three-level CE reduced the ROM to 12% (±10%), 9% (±12%), and 22% (±18%) in LB, FE, and AR, respectively. The anterior-only construct outperformed the intact state only in FE, with a significant ROM reduction to 57% (±35 %), 60% (±27%), and 62% (±35%) for one-, two- and three-level CE, respectively. The supplemental dorsal instrumentation provided significantly more stability than the anterior-only instrumentation regardless of the number of levels resected and the direction of motion. After cyclic loading, the absolute differences in stability between the two instrumentations remained significant while both instrumentations showed a comparable increase of ROM after cyclic loading. The large difference in the absolute ROM of anterior-only compared to circumferential instrumentations supports a dorsal support in case of three-level approaches.

Impact of firefighter gear on lower body range of motion

Purpose – The purpose of this paper is to investigate the incremental impact of firefighter’s personal protective equipment (PPE) on lower body range of motion (ROM) while walking to suggest areas of design improvement for enhanced mobility and safety. Design/methodology/approach – Eight male and four female firefighters participated in the study. Lower body ROM was assessed while they walked in four different configurations of PPE, including turnout ensemble, a self-contained breathing apparatus (SCBA) and boots. The impact of each added PPE item, and gender differences were statistically analyzed. Findings – Wearing firefighter turnout ensemble and SCBA reduced ROM in the lower body in the sagittal and transverse planes. A significant reduction in ROM for anterior-posterior movement at the ankle and the ball of the foot was found while wearing rubber boots with turnout ensemble and SCBA. This puts firefighters at higher risk of experiencing foot injuries and physical strains. A significant increase in medial-lateral movement of the foot while wearing rubber boots may increase risk of ankle sprains. A greater reduction in ROM at the ankle and the ball of the foot for female firefighters may imply greater risk for women compared to men, while wearing boots. Practical implications – Reducing the inflexibility and bulkiness of boots is critical to improve firefighter’s lower body mobility and safety. Originality/value – This study implemented 3-D motion capture technology to analyze how wearing firefighting gear impacted lower body motion. It provides quantitative evidence to recommend ergonomic boot re-design.

A novel lateral lumbar integrated plate-spacer interbody implant: in vitro biomechanical analysis

Background contextLateral spacers (LSs) are the standard of care for a lateral lumbar interbody fusion. However, various types of fixation, such as bilateral pedicle screws (BPSs), unilateral pedicle screws (UPSs), bilateral facet screws (BFSs), and lateral plates (LPs) have been reported to increase the stability of LSs. The biomechanics of a novel lateral interbody implant, which is an interbody spacer with an integrated plate and two bone screws (lateral integrated plate-spacer [IPS-L]), has not been investigated yet. PurposeTo compare the biomechanical stability of IPS-L and LS with and without supplemental instrumentation. Study designHuman lumbar cadaveric study evaluating the biomechanical stability of an IPS-L. MethodsEach of the six (L2–L5) spines was sequentially tested in intact; IPS-L; IPS-L+UPS; IPS-L+BPS; IPS-L+BFS; LS+BFS; LS+UPS; LS+BPS; LS; and LS+LP, using a load-control protocol in which a ±8 Nm moment was applied, for three cycles each, in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). Data results were obtained from the third cycle. ResultsThe IPS-L construct significantly reduced the range of motion (ROM) by 75% in FE, 70% in LB, and 57% in AR, compared with intact. Lateral integrated plate-spacer demonstrated similar biomechanical stability as LS+LP, and higher stability than the LS-alone construct, but the difference was not statistically significant. ConclusionsThe IPS-L evaluated in the present study demonstrated equivalent biomechanical stability compared with standard lateral interbody fusion constructs. The addition of BPSs to the IPS-L showed significant reduction in ROM in FE, and the addition of BFSs showed significant reduction in ROM in FE and AR, compared with the integrated plate-spacer alone construct. The IPS-L with supplemental fixation may be a viable option for lateral interbody fusion. Long-term clinical studies are further required to confirm these results.

Biomechanical evaluation of a metal-on-metal cervical intervertebral disc prosthesis

Background contextIn vitro nondestructive flexibility testing of the CerviCore total disc replacement (TDR) was performed. It was hypothesized that TDR would not significantly alter biomechanics relative to intact, whereas rigid fixation would cause significant changes. PurposeTo assess the ability of a cervical metal-on-metal saddle-shaped TDR to replicate normal biomechanics in vitro. Study designHuman cadaveric flexibility experiment. MethodsNine human cadaveric C3–T1 specimens were tested intact, after TDR and after anterior plating. Flexion, extension, lateral bending, and axial rotation were induced by pure moments; flexion-extension was then repeated using a simplified muscle force model with 70-N follower load. Optical markers measured three-dimensional intervertebral motion, and eight points of laminar surface strain were recorded near the left and right C5–C6 facet joints. Biomechanical parameters studied included range of motion (ROM), lax zone (LZ), angular coupling pattern, sagittal instantaneous axis of rotation (IAR), and facet loads normal to the facet joint plane. Mean values of parameters were compared statistically using repeated measures analysis of variance and Holm-Sidak tests. ResultsTotal disc replacement caused significant reduction in ROM during extension (p=.004) and significant reduction in LZ during lateral bending (p=.01). However, plating significantly reduced both ROM and LZ during flexion, extension, and lateral bending (p<.006). Sagittal IAR shifted relative to intact by 3.6 mm after TDR (p>.05) and 6.5 mm after plating (p>.05). Coupled axial rotation/degree lateral bending was 99% of intact after TDR but 76% of intact after plating (p=.15). Coupled lateral bending/degree axial rotation was 95% of intact after TDR but 85% of intact after plating (p=.43). Neither construct altered facet loads from intact. ConclusionsWith regard to ROM, LZ, IAR, and coupling, deviations from intact biomechanics were less substantial after TDR than after plating. Facet load alterations were minimal with either construct. Our results show that this particular TDR permits ROM and maintains some measures of kinematics in a cadaver model.

Relation between radiological assessment and biomechanical stability of lumbar interbody fusion in a large animal model

To relate the progress of vertebral segmental stability after interbody fusion surgery with radiological assessment of spinal fusion. Twenty goats received double-level interbody fusion and were followed for a period of 3, 6 and 12 months. After killing, interbody fusion was assessed radiographically by two independent observers. Subsequently, the lumbar spines were subjected to four-point bending and rotational deformation, assessed with an optoelectronic 3D movement registration system. In addition, four caprine lumbar spines were analysed in both the native situation and after the insertion of a cage device, as to mimic the direct post-surgical situation. The range of motion (ROM) in flexion/extension, lateral bending and axial rotation was analysed ex vivo using a multi-segment testing system. Significant reduction in ROM in the operated segments was already achieved with moderate bone ingrowth in flexion/extension (71 % reduction in ROM) and with only limited bone ingrowth in lateral bending (71 % reduction in ROM) compared to the post-surgical situation. The presence of a sentinel sign always resulted in a stable vertebral segment in both flexion/extension and lateral bending. For axial rotation, the ROM was already limited in both native and cage inserted situations, resulting in non-significant differences for all radiographic scores. In vivo vertebral segment stability, defined as a significant reduction in ROM, is achieved in an early stage of spinal fusion, well before a radiological bony fusion between the vertebrae can be observed. Therefore, plain radiography underestimates vertebral segment stability.

Biomechanical Analysis of Sacral Screw Strain and Range of Motion in Long Posterior Spinal Fixation Constructs

A cadaveric biomechanical experiment was conducted to assess the range of motion (ROM) and screw strain at S1 in a long instrumented spinal fusion construct to compare the effects of various surgical strategies for L5-S1 stabilization. To directly quantify and compare S1 screw strains and lumbosacral ROM for 4 different L2-S1 posterior segmental instrumented fusion constructs: an L2-S1 pedicle screw (PS) construct alone and PS with each of 3 different augmentations, anterior lumbar intebody fusion (ALIF), anterior axial interbody threaded rod (AxiaLITR), or iliac screws. Iliac screws and anterior interbody devices are commonly used as augmentation to reduce the incidence of S1 screw loosening in long fusion constructs. Alternatives, such as AxiaLITR, may provide similar biomechanical advantages without many of the same long-term limitations and morbidities. Pure moment flexibility testing was performed in 6 cadaveric lumbosacral spines. Specimens were tested with 4 instrumentation constructs: (1) PS L2-S1, (2) PS with ALIF, (3) PS with AxiaLITR, and (4) PS with iliac screws. Bilateral S1 PS were instrumented with strain gauges, directly measuring screw loading while simultaneously measuring L5-S1 ROM with a noncontact camera system. Average S1 screw strains were the greatest with the PS group and were reduced by 38% with the ALIF group, 75% with the AxiaLITR group, and 78% with the iliac screw group in flexion-extension (P < 0.05). Similar trends were observed in torsion (P < 0.05). Strains in lateral bending were smaller in magnitude and were similar among all 4 constructs. The AxiaLITR and iliac screw groups demonstrated a similar ROM and significant reduction in ROM at L5-S1 compared with both the PS and ALIF groups (P ≤ 0.02 and P < 0.03). The results of this study indicated that iliac screws and AxiaLITR provide similar stability at L5-S1, while significantly reducing the strain on the S1 screws.

Total Condylar Unipolar Expandable Prosthesis for Proximal Tibia Malignant Bone Tumors in Early Childhood

Wide resection and reconstruction of tumors of the proximal tibia in the pediatric population are challenging procedures. The use of hinged, expandable prostheses may cause early closure of the distal femoral growth plate, which may increase the risk of limb discrepancy already present in this population. Between 1991 and 2001, 2 girls and 1 boy, aged 6, 6, and 4 years, respectively, were diagnosed with osteosarcoma of the proximal tibia and treated with wide resection and reconstruction with a condylar unipolar expandable tibial prosthesis. A press-fitted technique was used for component insertion. All patients received neoadjuvant and adjuvant chemotherapy. Radiographic and functional follow-up took place at least once a year for a minimum of 4 years. Adequate pain control, limb-length equality, and acceptable function were obtained in all patients. One patient presented with significant range of motion reduction (0°- 30°) in the affected knee. Limb lengthening was performed as needed to maintain balanced limb length. All patients had a good Musculoskeletal Tumor Society category score. No complications occurred in terms of component loosening or infection. One patient died shortly after 4-year follow-up because of doxorubicin-induced leukemia. Currently used hinged, expandable prostheses can jeopardize the unaffected distal femoral growth plate. This article describes a technique of reconstruction that spares the distal femoral growth plate. Adequate limb length can be expected with acceptable functional outcome. However, it is imperative to keep in perspective the expectations of the physician, the physician's team, the patient, and the patient's family.

Videoradiographic analysis of the range of motion in unilateral experimental knee joint arthritis in rats

IntroductionThe translational and predictive value of animal models highly depends on the validity of respective readout parameters. In arthritis research, there has been a shift from sole threshold testing for pain-related behavior, as well as from swelling and histology assessment for inflammation, toward an analysis of joint function as indicated, for instance, by an increasing number of studies on gait abnormalities. Clinically, the range of motion (ROM) of the affected joint plays a major role in diagnosis and the assessment of treatment benefits. This parameter, however, is only insufficiently detected by currently used analytic systems in animals.MethodsHere we used high-resolution videoradiographic analysis to assess ROM in experimental knee joint arthritis in rats. This parameter is described during the 21-day course of antigen-induced arthritis in rats. Furthermore, the therapeutic effects of antinociceptive (morphine) and anti-inflammatory (dexamethasone) treatment on ROM are documented. To obtain additional information on the implications of ROM in animal models, correlations were performed to measure pain-related behavior and inflammation.ResultsThe study animals showed a significant reduction in ROM of the inflamed knee joint in the acute phase of arthritis. This was accompanied by an increase in knee joint movement on the contralateral side, indicating a compensational mechanism. Both morphine and dexamethasone treatment increased and thus normalized ROM. Changes in ROM were further stage-dependently correlated with weight bearing and joint swelling, that is, with both pain-related behavior and signs of inflammation.ConclusionsThe dynamic ROM observed in freely moving rats in our model of knee joint arthritis might serve as a parameter for global disease activity and might thus represent a promising readout parameter for preclinical assessment regarding the overall efficacy not only of antiarthritic but also of antinociceptive compounds.

Obesity effect on male active joint range of motion

Despite the prevalence of obesity, how obesity affects human physical capabilities is not well documented. As an effort toward addressing this, the current study investigated the obesity effect on joint range of motion (RoM) based on data collected from 20 obese and 20 non-obese males. In total, 30 inter-segmental motions occurring at the shoulder, elbow, knee and ankle joints and lumbar and cervical spine areas were examined. The obesity effect was found to be non-uniform across the joint motions. Obesity significantly reduced RoM for nine of the 30 motions: shoulder extensions and adductions, lumbar spine extension and lateral flexions and knee flexions. The largest significant RoM reduction was 38.9% for the left shoulder adduction. The smallest was 11.1% for the right knee flexion. The obesity-associated RoM reductions appear to be mainly due to the mechanical interposition and obstruction of inter-segmental motions caused by excess fat in the obese body. Statement of Relevance: Currently, obesity is prevalent worldwide and its prevalence is expected to increase continually in the near future. This study empirically characterised the obesity effects on joint RoM to provide better understanding of the physical capabilities of the obese. The study findings will facilitate designing man–artefact systems that accommodate obese individuals.

Interbody device endplate engagement effects on motion segment biomechanics

Background Context Stand-alone nonbiologic interbody fusion devices for the lumbar spine have been used for interbody fusion since the early 1990s. However, most devices lack the stability found in clinically successful circumferential fusion constructs. Stability results from cage geometry and device/vertebral endplate interface integrity. To date, there has not been a published comparative biomechanical study specifically evaluating the effects of endplate engagement of interbody devices. Purpose Lumbar motion segments implanted with three different interbody devices were tested biomechanically to compare the effects of endplate engagement on motion segment rigidity. The degree of additional effect of supplemental posterior and anterior fixation was also investigated. Study Design/Setting A cadaveric study of interbody fusion devices with varying degrees of endplate interdigitation. Outcome Measures Implanted motion segment range of motion (ROM), neutral zone (NZ), stiffness, and disc height. Methods Eighteen human L23 and L45 motion segments were distributed into three interbody groups (n=6 each) receiving a polymeric (polyetheretherketone) interbody spacer with small ridges; a modular interbody device with endplate spikes (InFix, Abbott Spine, Austin, TX, USA); or dual tapered threaded interbody cages (LT [Lordotic tapered] cage; Medtronic, Memphis, TN, USA). Specimens were tested intact using a 7.5-Nm flexion-extension, lateral bending, and axial torsion flexibility protocol. Testing was repeated after implantation of the interbody device, anterior plate fixation, and posterior interpedicular fixation. Radiographic measurements determined changes in disc height and intervertebral lordosis. ROM and NZ were calculated and compared using analysis of variance. Results The interbody cages with endplate spikes or threads provided a statistically greater increase in disc height versus the polymer spacer (p=.01). Relative to intact, all stand-alone devices significantly reduced ROM in lateral bending by a mean 37% to 61% (p≤.001). The cages with endplate spikes or threads reduced ROM by ∼50% and NZ by ∼60% in flexion-extension (p≤.02). Only the cage with endplate spikes provided a statistically significant reduction in axial torsion ROM compared with the intact state (50% decrease, p<.001). Posterior fixation provided a significant reduction in ROM in all directions versus the interbody device alone (p<.001). Anterior plating decreased ROM over interbody device alone in flexion-extension and torsion but did not have additional effect on lateral bending ROM. Conclusion The cages with endplate spikes or threads provide substantial motion segment rigidity compared with intact in bending modes. Only the cages with endplate spikes were more rigid than intact in torsion. All devices experienced increased rigidity with anterior plating and even greater rigidity with posterior fixation. It appears that the endplate engagement with spikes may be beneficial in limiting torsion, which is generally difficult with other “stand-alone” devices tested in the current and prior reports.