Biomechanical Device Research Articles

Antibiotic-impregnated polymethylmethacrylate as an anterior biomechanical device for the treatment of cervical discitis and vertebral osteomyelitis: technical report of two cases

To evaluate the feasibility of this novel surgical approach for treatment of cervical discitis and vertebral osteomyelitis. This is a report of two patients who underwent anterior cervical decompression for discitis and vertebral osteomyelitis (DVO) with cervical spine reconstruction with polymethylmethacrylate impregnated with antibiotics (AI-PMMA). Both patients had successful procedures that were followed by 6 weeks of intravenous antibiotics. Stabilization and eradication of infection was achieved with clinical and radiographic stabilization seen in both. Follow-up is greater than 18 months and both patients remain off antibiotics. The described technique using AI-PMMA offers immediate structural stability and local delivery of high concentration of antibiotics. Use in two patients has demonstrated a cost effective, long-term biomechanically stable construct and infection control.

Sequential Compression Biomechanical Device Versus Primary Amputation in Patients With Critical Limb Ischemia

Patients with critical limb ischemia (CLI), who are unsuitable for intervention, face the consequence of primary amputation. Sequential compression biomechanical device (SCBD) therapy provides a limb salvage option for these patients. To assess the outcome of SCBD in patients with severe CLI who are unsuitable for revascularization. Primary end points were limb salvage and 30-day mortality. From 2005 to 2012, 189 patients with severe CLI were not suitable for revascularization. In all, 171 joined the SCBD program. We match controlled 75 primary amputations. All patients were Rutherford category 4 or higher. Sustained clinical improvement was 68% at 1 year. Mean toe pressure increased from 19.9 to 35.42 mm Hg, P < .0001. Mean popliteal flow increased from 35.44 to 55.91 cm/sec, P < .0001. The 30-day mortality was 0.6%. Limb salvage was 94% at 5 years. Freedom from major adverse clinical events was 62.5%. All-cause survival was 69%. Median cost of managing a primary amputation patient is €29,815 compared to €3,985 for SCBD. We treated 171 patients with artassist at a cost of €681,965. However, primary amputation for 75 patients cost €2,236,125. The SCBD therapy is a cost-effective and clinically effective solution in patients with CLI having no option of revascularization. It provides adequate limb salvage while providing relief of rest pain without any intervention.

The evolution of technology.

The historical development of technologies for catheter-based reperfusion of the acutely ischemic human brain is brief but eventful (Table). The first clinical patients were treated with local microcatheter delivery of intra-arterial fibrinolytics in the mid-1990s. The first mechanical recanalization technique, primary intra-arterial balloon angioplasty, was described a few years later. Over the subsequent decade and a half, successive waves of innovative mechanical thrombectomy devices were introduced. The rapid proliferation of technology reflects the inherent dynamic of biomechanical device development, characterized by rapid engineering innovation focused on a well-circumscribed target, in contrast to the slower, more deliberate arc of drug development, which requires extensive testing of each new molecular entity for unexpected off-target effects on diverse organs. The heterogeneity of target vascular lesions in cerebrovascular disease mandates a diversity of mechanical treatment options for deployment by interventionalists. In many patients, the intracranial occlusion is an embolus that has arisen from the heart or a proximal aortocervical arterial source and landed in a relatively normal recipient artery. Such target thrombi respond well to retrieval and aspiration strategies. In other patients, the occlusive lesion is comprised of an in situ intracranial atherosclerotic plaque with supervening thrombosis. These target lesions will not respond well to retrieval devices, which catch on the plaque, or to aspiration devices, which are effective only for the thrombus component. However, they do respond well to angioplasty and stenting, which accomplish controlled cracking and dissection of the underlying atherosclerotic lesions.1 There is a notable race, ethnic variation in the composition of intracranial occlusions.2 Among whites, emboli from the heart or extracranial arterial sources are common; among Asians and blacks, in situ intracranial atherosclerosis with supervening thrombosis is more frequent. As a result, the most effective and commonly used mechanical treatment strategies vary regionally across the globe. The endovascular …

A non-invasive biomechanical device and treatment for patients following total hip arthroplasty: results of a 6-month pilot investigation

BackgroundThe purpose of the study was to examine the effect of a foot-worn biomechanical device on the clinical measurements and gait patterns of patients with total hip arthroplasty (THA).MethodsNineteen patients, up to 3 months post-THA, were enrolled to the study. Patients underwent a computerized gait analysis to calculate spatiotemporal parameters and completed the Western Ontario and McMaster Universities osteoarthritis index and the SF-36 health survey. Patients then began therapy with a non-invasive foot-worn biomechanical device coupled with a treatment methodology (AposTherapy). Patients received exercise guidelines and used the device daily during their regular activities at their own environment. Follow-up examinations were conducted after 4, 12, and 26 weeks of therapy. Repeated measures ANOVA was used to evaluate changes over time. The clinical significance of the treatment effect was evaluated by computing the Cohen's effect sizes (ES statistic).ResultsAfter 26 weeks of therapy, a significant improvement was seen in gait velocity (50.3%), involved step length (22.9%), and involved single limb support (16.5%). Additionally, a significant reduction in pain (85.4%) and improvement in function (81.1%) and quality of life (52.1%) were noted.ConclusionsPatients following THA demonstrated a significant improvement in gait parameters and in self-assessment evaluations of pain, function, and quality of life. We recommend further RCTs to examine the effect of this therapy compared to other rehabilitation modalities following THA and compared to healthy matched controls.Trial registrationClinical trial registration number NCT01266382

A Non-invasive Foot-worn biomechanical device and treatment for patients with hip osteoarthritis

A Non-invasive Foot-worn biomechanical device and treatment for patients with hip osteoarthritis

The outcome of a novel biomechanical therapy for patients suffering from anterior knee pain

article i nfo Background: Thisstudywas devisedtoexamine theeffect of a novel biomechanicaltherapyforpatientssuffering from anterior knee pain (AKP). Methods: A retrospective analysis of 48 patients suffering from AKP was performed. Patients underwent a gait evaluation, using an electronic walkway mat, and completed the SF-36 health survey and the WOMAC questionnaire at baseline and after 3 and 6 months of therapy. A special biomechanical device was individually calibrated for each patient. AposTherapy is a functional, non-invasive rehabilitation ther- apy consisting of a biomechanical foot-worn device that is used during activities of daily living. Repeated measures analyses were performed to compare gait parameters and self-evaluation questionnaires between baseline, 3 months and 6 months. Results: Walking velocity significantly increased by 5.7 cm/s, cadence increased by 1.6 steps/minute, and stride lengthincreasedby3.4 cminrelationtopretreatmenttesting(pb0.001 for all). End-point evaluation revealed ad- ditional improvement of these parameters; however these did not significantlydifferfrom that of mid-treatment. Pain decreased by 36.6% and 49.2% following 13 and 26 weeks of treatment, respectively (Pb0.01) and function improved by 25.2% and 41.7% following 13 and 26 weeks of treatment, respectively (P=0.01). Conclusions: Based on the current study's results it may be concluded that this therapy might have a positive ef- fect for patients with AKP.

Long-Term Effects of AposTherapy in Patients with Osteoarthritis of the Knee: A Two-Year Followup

Several biomechanics treatments for knee osteoarthritis (OA) have emerged with the goal of reducing pain and improving function. Through this, researchers have hoped to achieve a transition from the pathological gait patterns to coordinated motor responses. The purpose of the study was to determine the long-term effects of a therapy using a biomechanical device in patients with knee OA. Patients with knee OA were enrolled to active and control groups. The biomechanical device used in therapy (AposTherapy) was individually calibrated to each patient in the active group. Patients in the control group received standard treatment. Outcomes were the Western Ontario and McMaster Osteoarthritis Index (WOMAC), Aggregated Locomotor Function (ALF), Short Form 36 (SF-36), and Knee Society Score assessments. The active and control groups were similar at the baseline (group difference in all scores P > 0.05). The active group showed a larger improvement over time between groups in all three WOMAC categories (F = 16.8, 21.7, and 18.1 for pain, stiffness, and function; all P < 0.001), SF-36 Physical Scale (F = 5.8; P = 0.02), Knee Society Knee Score (F = 4.3; P = 0.044 ), and Knee Society Function Score (F = 6.5; P = 0.014 ). At the two-year endpoint, the active group showed significantly better results (all P ≤ 0.001). The groups showed a difference of 4.9, 5.6, and 4.7 for the WOMAC pain, stiffness, and function scores, respectively, 10.8 s in ALF score, 30.5 in SF-36 Physical Scale, 16.9 in SF-36 Mental Scale, 17.8 in Knee Society Knee Score, and 25.2 in Knee Society Function Score. The biomechanical therapy examined was shown to significantly reduce pain and improve function and quality of life of patients with knee OA over the long term.

Foot Center of Pressure Trajectory Alteration by Biomechanical Manipulation of Shoe Design

Footwear-generated biomechanical manipulations have been shown to alter lower limb kinetics. It has been suggested that this is due to altered trajectory of the foot's center of pressure (COP), conveying a shift in location of the ground reaction force and modifying moments and forces acting on proximal body segments. However, past studies have focused on qualitative association between footwear design and the COP locus. Moreover, this association was calculated via indirect analysis. The purpose of the present study was to directly examine and quantify the correlation between measured footwear biomechanical manipulation and the location of the COP trajectory during gait. A novel biomechanical device allowing flexible positioning of 2 convex-shaped elements attached to its sole was utilized. A total of 20 healthy male adults underwent direct in-shoe pressure measurements while walking with the device set at 7 mediolateral configurations. COP data were collected during gait and analyzed with respect to different stance subphases. COP location significantly correlated with a shift of the elements medially or laterally. The linear model describing this correlation was found to be statistically significant. There was significant correlation between the plantar orientation of the shoe device configuration and the COP. Changes in COP trajectory may be valuable in patients suffering from multiple foot disorders elevating pressure on the foot. Accurate COP control could aid in the manipulation of the forces acting on the proximal joints during gait. In addition, these findings may have implications in the field of biomechanical apparatus design and practice.

A Non-Invasive Foot-Worn Biomechanical Device for Patients with Hip Osteoarthritis

Objective: The purpose of this study was to evaluate the effect of a biomechanical therapy on the pain, function, quality of life and spatio-temporal gait patterns of patients with hip osteoarthritis (OA). Design: 60 patients with hip OA were examined before and after twelve weeks of a personalized biomechanical therapy (AposTherapy). Patients were evaluated using the WOMAC questionnaire for pain and function and the SF-36 Health Survey for quality of life, and underwent a computerized gait test. Results: After twelve weeks of treatment, a significant improvement was found in the patients’ velocity, step length and cadence (P ≤ 0.001). WOMAC-pain, stiffness and function subscales were significantly improved compared to baseline (P ≤ 0.001). SF-36 physical score subscale improved significantly (P=0.007). Conclusions: Patients with bilateral hip OA treated with AposTherapy for twelve weeks showed statistically and clinically significant improvements in pain, function and gait patterns.

The outcome of a novel biomechanical therapy for patients suffering from anterior knee pain

BackgroundThis study was devised to examine the effect of a novel biomechanical therapy for patients suffering from anterior knee pain (AKP). MethodsA retrospective analysis of 48 patients suffering from AKP was performed. Patients underwent a gait evaluation, using an electronic walkway mat, and completed the SF-36 health survey and the WOMAC questionnaire at baseline and after 3 and 6months of therapy. A special biomechanical device was individually calibrated for each patient. AposTherapy is a functional, non-invasive rehabilitation therapy consisting of a biomechanical foot-worn device that is used during activities of daily living. Repeated measures analyses were performed to compare gait parameters and self-evaluation questionnaires between baseline, 3months and 6months. ResultsWalking velocity significantly increased by 5.7cm/s, cadence increased by 1.6 steps/minute, and stride length increased by 3.4cm in relation to pretreatment testing (p<0.001 for all). End-point evaluation revealed additional improvement of these parameters; however these did not significantly differ from that of mid-treatment. Pain decreased by 36.6% and 49.2% following 13 and 26 weeks of treatment, respectively (P<0.01) and function improved by 25.2% and 41.7% following 13 and 26 weeks of treatment, respectively (P=0.01). ConclusionsBased on the current study's results it may be concluded that this therapy might have a positive effect for patients with AKP.

NONLINEAR DYNAMICS AND THE SYNTHESIS OF ZEBRA FINCH SONG

Behavior emerges as the interaction between a nervous system, a peripheral biomechanical device and the environment. In birdsong production, this observation is particularly important: songbirds are an adequate animal model to unveil how brain structures reconfigure themselves during learning of a complex behavior as song. Therefore, it is important to understand which features of behavior are controlled by independent tuning of neurophysiological parameters, and which are constrained by the biomechanics of the peripheral vocal organ. In this work, we show that many of the acoustic features in the Zebra finch song are in fact conditioned by the biomechanics involved.

BIOMECHANICAL ACCESS METHOD FOR ANALYZING ISOMETRICITY IN RECONSTRUCTING THE MEDIAL PATELLOFEMORAL LIGAMENT

Objective: To present a biomechanical device for evaluating medial patellofemoral ligament (MPFL) reconstruction and its isometricity. Methods: An accessible biomechanical method that allowed application of physiological and non-physiological forces to the knee using a mechanical arm and application of weights and counterweights was developed, so as to enable many different evaluations and have a very accurate measurement system for distances between different structures, for analysis on experiments. This article describes the assembly of this system, and suggests some practical applications. Six cadaver knees were studied. The knees were prepared in a testing machine developed at the Biomechanics Laboratory of IOT–HCFMUSP, which allowed dynamic evaluation of patellar behavior, with quantification of patellar lateralization between 0° and 120°. The differences between the distances found with and without load applied to the patella were grouped according to the graft fixation angle (0°, 30°, 60° or 90°) and knee position (intact, damaged or reconstructed). Results: There was a tendency for smaller lateral displacement to occur at fixation angles greater than 30 degrees of flexion, especially between the angles of 45° and 60° degrees of flexion, after the reconstruction. For the other angles, there was no statistical significance. Conclusion: The method developed is a useful tool for studies on the patellofemoral joint and the MPFL, and has a very accurate measurement system for distances between different structures. It can be used in institutions with fewer resources available.

A unique foot-worn device for patients with degenerative meniscal tear

PurposeThe purpose of the current study was to assess the effects of a new foot-worn device on the gait, physical function and pain in patients suffering from knee osteoarthritis (OA) who had a low-impact injury to the medial meniscus causing a degenerative meniscal tear.MethodsA retrospective analysis of 34 patients with knee OA and a degenerative medial meniscal tear was performed. Patients underwent a gait evaluation, using an electronic walkway mat, and completed the SF-36 health survey and the WOMAC questionnaire at baseline and after 3 and 12 months of therapy. AposTherapy is a functional, biomechanical, non-invasive rehabilitation therapy consisting of a foot-worn device that is individually calibrated to each patient and is used during activities of daily living. Repeated-measures analyses were performed to compare gait parameters and self-evaluation questionnaires between baseline, and 3 and 12 months.ResultsSignificant improvements were found in gait velocity, step length and single-limb support of the involved knee following 12 weeks of therapy (all p < 0.01), alongside an improvement in limb symmetry. These results were maintained at the 12-month follow-up examination. Significant improvements were also found in all three domains of the WOMAC index (pain, stiffness and physical function) and in the SF-36 Physical Health Scale and the SF-36 Mental Health Scale (all p < 0.01).ConclusionsPatients with knee OA and a degenerative medial meniscal tear using a biomechanical foot-worn device for a year showed improvement in gait, physical function and pain. Based on the findings of this study, it can be postulated that this biomechanical device might have a positive effect on this population.Level of evidenceTherapeutic study, Level IV.

A new non-invasive biomechanical therapy for knee osteoarthritis improves clinical symptoms and gait patterns

BACKGROUND The management of knee osteoarthritis (OA) focuses on reducing the levels of pain and disability. Recently, a novel biomechanical device and treatment methodology (AposTherapy) was shown to reduce the knee adduction moment while simultaneously challenging the neuromuscular control system through perturbation. AIM The purpose of the study was to investigate the changes in gait patterns and clinical measurements following treatment with a novel biomechanical device on patients with knee OA. METHODS A total of 745 patients with bilateral knee OA were analyzed. Patients completed a gait test, Western Ontario and McMaster Osteoarthritis Index (WOMAC) questionnaire and SF-36 Health Survey at baseline and after 12 weeks. The biomechanical device was individually calibrated to each patient. Shifting the center of pressure, through changes in the location of the biomechanical elements causes realignment and reduction in the knee adduction moment. Furthermore the configuration of the biomechanical element allows training under controlled perturbation. RESULTS A significant decrease was found in WOMAC pain (28.6%) and WOMAC function (25.2%) following three months of therapy (p<0.001). A significant increase was found in the patients' physical quality of life (17.8%) and mental quality of life (11.0%) (p<0.001). Gait velocity, cadence step length, stance phase and single limb support phase improved significantly following three months of therapy (7.6%, 4%, 3.7% and 1.6%, respectively). CONCLUSIONS Our results suggest an overall improvement in the gait patterns, level of pain, function and quality of life of patients with knee OA following three months of AposTherapy.

Reduction in knee adduction moment via non-invasive biomechanical training: A longitudinal gait analysis study

Biomechanical non-invasive interventions have been previously reported to reduce pain and facilitate superior levels of function in patients with medial knee osteoarthritis [OA]. One such treatment is the AposTherapy, a customized program utilizing a foot-worn biomechanical device allowing center of pressure modification and continuous perturbation during gait. The influence of this intervention on objective gait metrics has yet to be determined. The aim of the current study was to prospectively examine changes in kinetic and kinematic parameters in patients enrolled in this treatment program. Twenty-five females with symptomatic bilateral medial compartment knee OA were enrolled in the customized daily treatment program. All patients underwent barefoot gait analysis testing and completed subjective questionnaires prior to treatment initiation and on two follow-up visits. Significantly reduced knee adduction moment (KAM) magnitude was noted during barefoot walking after three and nine months of treatment. On average, the knee adduction impulse and the 1st and 2nd KAM peaks were reduced by 13%, 8.4%, and 12.7%, respectively. Furthermore, moment reduction was accompanied by elevated walking velocity, significant pain reduction, and increased functional activity. In addition to symptomatic improvement, our results suggest that this treatment program can alter kinetic gait parameters in this population. We speculate that these adaptations account for the symptomatic and functional improvement reported for this intervention.

378 Revitalizing a Vital Sign: Measurement of Respiratory Rate With a Thoracic Belt Improves Detection of Tachypnea at Primary Triage

Prior studies demonstrate that busy emergency department (ED) nursing (RN) assessment of respiratory rate (RR) at triage is inaccurate. Although electronic methods have been evaluated, none have provided an improved measurement of RR. A newly developed biomechanical device, (coined BioHarness® [BH], Zephyr Technology, Inc.), employs a thoracic pressure sensor to detect respirations and has potential utility in ED triage. We conducted a pilot study to assess the sensitivity of BH versus RN, relative to gold standard (GS) measurement through direct observation of respirations, for identifying tachypnea (defined as RR > 20 breaths per minute [BPM]).

Monitoring micrometer-scale collagen organization in rat-tail tendon upon mechanical strain using second harmonic microscopy

We continuously monitored the microstructure of a rat-tail tendon during stretch/relaxation cycles. To that purpose, we implemented a new biomechanical device that combined SHG imaging and mechanical testing modalities. This multi-scale experimental device enabled simultaneous visualization of the collagen crimp morphology at the micrometer scale and measurement of macroscopic strain–stress response. We gradually increased the ultimate strain of the cycles and showed that preconditioning mostly occurs in the first stretching. This is accompanied by an increase of the crimp period in the SHG image. Our results indicate that preconditioning is due to a sliding of microstructures at the scale of a few fibrils and smaller, that changes the resting length of the fascicle. This sliding can reverse on long time scales. These results provide a proof of concept that continuous SHG imaging performed simultaneously with mechanical assay allows analysis of the relationship between macroscopic response and microscopic structure of tissues.

Sequential compression biomechanical device in patients with critical limb ischemia and nonreconstructible peripheral vascular disease

Critical limb ischemia (CLI) patients who are unsuitable for intervention face the dire prospect of primary amputation. Sequential compression biomechanical device (SCBD) therapy provides a limb salvage option for these patients. This study assessed the outcome of SCBD in severe CLI patients who otherwise would face an amputation. Primary end points were limb salvage and 30-day mortality. Secondary end points were hemodynamic outcomes (increase in popliteal artery flow and toe pressure), ulcer healing, quality-adjusted time without symptoms of disease or toxicity of treatment (Q-TwiST), and cost-effectiveness. From 2004 to 2009, we assessed 4538 patients with peripheral vascular disease (PVD). Of these, 707 had CLI, 518 underwent intervention, and 189 were not suitable for any intervention. A total of 171 patients joined the SCBD program for 3 months. All patients were Rutherford category ≥4. Median follow-up was 13 months. Mean toe pressure increased from 39.9 to 55.42 mm Hg, with a mean difference in toe pressure of 15.49 mm Hg (P = .0001). Mean popliteal flow increased from 35.44 to 55.91 cm/s, with mean difference in popliteal flow of 20.47 cm/s (P < .0001). Mortality at 30 days was 0.6%. Median amputation-free survival was 18 months. Limb salvage at 3.5 years was 94%. Freedom from major adverse clinical events (MACE) at 4.5 years was 62.5%. We treated 171 patients with SCBD at a cost of €681,948, with an estimated median per-patient cost of treatment with SCBD of €3988. SCBD therapy is a cost-effective and clinically efficacious solution in CLI patients with no option of revascularization. It provides adequate limb salvage and ameliorated amputation-free survival while providing relief of rest pain without any intervention.

Effect of center of pressure modulation on knee adduction moment in medial compartment knee osteoarthritis

The knee adduction moment (KAM) provides a major contribution to the elevated load in the medial compartment of the knee. An abnormally high KAM has been linked with the progression of knee osteoarthritis (OA). Footwear-generated biomechanical manipulations reduce the magnitude of this moment by conveying a more laterally shifted trajectory of the foot's center of pressure (COP), reducing the distance between the ground reaction force and the center of the knee joint, thus lowering the magnitude of the torque. We sought to examine the outcome of a COP shift in a cohort of female patients suffering from medial knee OA. Twenty-two female patients suffering from medial compartment knee OA underwent successive gait analysis testing and direct pedobarographic examination of the COP trajectory with a foot-worn biomechanical device allowing controlled manipulation of the COP. Modulation of the COP coronal trajectory from medial to lateral offset resulted in a significant reduction of the KAM. This trend was demonstrated in subjects with mild-to-moderate OA and in patients suffering from severe stages of the disease. Our results indicate that controlled manipulation of knee coronal kinetics in individuals suffering from medial knee OA can be facilitated by customized COP modification.

The effect of manipulation of the center of pressure of the foot during gait on the activation patterns of the lower limb musculature

Background Therapeutic devices that manipulate the center of pressure (COP) of the foot can induce kinetic and kinematic changes in gait. Appropriate changes in joint moments and muscle activation during gait have been proven to be beneficial for patients with neuromuscular and orthopedic disorders. The purpose of this study was to investigate the effect of different COP positions during gait on the activity of the lower limb musculature of healthy subjects. Methods A novel foot-worn biomechanical device that allows controlled manipulation of the COP during gait was used. Twelve healthy males underwent EMG analyses of the key muscles of the leg while wearing the device. The trials were carried out at six COP positions relative to neutral configuration: anterior, posterior, medial, lateral, dorsi flexion and plantar flexion. Results The EMG activity of the lateral gastrocnemius varied significantly with COP during terminal stance ( p = 0.023) and preswing ( p = 0.020), the tibialis anterior during load response ( p = 0.019) and midstance ( p = 0.004), the biceps femoris during terminal stance ( p = 0.009) and the vastus lateralis during initial contact ( p = 0.010). Conclusion There are significant changes in the muscle activity of the lower limb in response to manipulation of the COP of the foot during gait.