Non-pharmacological treatment and prevention of bone loss after spinal cord injury: a systematic review

A NEW POSTURAL MOTOR RESPONSE TO SPINAL CORD STIMULATION: POST-STIMULATION REBOUND EXTENSION

Spinal cord stimulation (SCS) has emerged as a therapeutic tool for improving motor function following spinal cord injury. While many studies focus on restoring locomotion, little attention is paid to enabling standing which is a prerequisite of walking. In this study, we fully characterize a new type of response to SCS, a long extension activated post-stimulation (LEAP). LEAP is primarily directed to ankle extensors and hence has great clinical potential to assist postural movements. To characterize this new response, we used the decerebrate cat model to avoid the suppressive effects of anesthesia, and combined EMG and force measurement in the hindlimb with intracellular recordings in the lumbar spinal cord. Stimulation was delivered as five-second trains via bipolar electrodes placed on the cord surface, and multiple combinations of stimulation locations (L4 to S2), amplitudes (50-600 uA), and frequencies (10-40 Hz) were tested. While the optimum stimulation location and frequency differed slightly among animals, the stimulation amplitude was key for controlling LEAP duration and amplitude. To study the mechanism of LEAP, we performed in vivo intracellular recordings of motoneurons. In 70% of motoneurons, LEAP increased at hyperpolarized membrane potentials indicating a synaptic origin. Furthermore, spinal interneurons exhibited changes in firing during LEAP, confirming the circuit origin of this behavior. Finally, to identify the type of afferents involved in generating LEAP, we used shorter stimulation pulses (more selective for proprioceptive afferents), as well as peripheral stimulation of the sural nerve (cutaneous afferents). The data indicates that LEAP primarily relies on proprioceptive afferents and has major differences from pain or withdrawal reflexes mediated by cutaneous afferents. Our study has thus identified and characterized a novel postural motor response to SCS which has the potential to expand the applications of SCS for patients with motor disorders.

Low-frequency pulsed electromagnetic fields alleviate the condylar cartilage degeneration and synovitis at the early stage of temporomandibular joint osteoarthritis

BACKGROUND

Temporomandibular joint osteoarthritis (TMJOA) is characterized by articular cartilage degeneration and progressive synovitis. How to effectively inhibit TMJOA in the early stage has been a hot topic in the biomedical field. As a non-invasive physiotherapy, pulsed electromagnetic field (PEMF) treatment has shown great potential in the treatment of osteoarthritis (OA) in extremity joints.

OBJECTIVE

This study aims to investigate the biological effect of PEMF intervention on TMJ cartilage degeneration and synovium inflammation at the early stage of TMJOA.

METHODS

PEMF (2.0 mT, 15 Hz, 2 h/day) treatment was given to rats in which TMJOA was induced by applying the unilateral anterior crossbite (UAC). Histological and immunohistochemical staining, TUNEL assay, real-time PCR and western blotting assay were performed to detect the changes of the morphology and the expression of pro-inflammatory and degradative factors in condylar cartilage and synovium.

RESULTS

Obvious condylar cartilage degeneration, characterized by decreased cartilage thickness, degraded cartilage extracellular matrix, increased expression of pro-inflammatory and degradative factors (TNF-α, IL-1β, MMP-13, ADAMTS-5, IL-6, MMP-3, MMP-9 and COL-X) and increased chondrocytes death, was observed in UAC group, accompanied by synovium hyperplasia and up-regulation of pro-inflammatory and degradative factors in synovium. PEMF intervention reversed the decreased cartilage thickness at 3 weeks and degraded cartilage extracellular matrix at 6 weeks. Moreover, the up-regulation of pro-inflammatory, degradative and hypertrophyic factors and chondrocytes death in condylar cartilage induced by UAC were inhibited to some extent. In addition, the synovium hyperplasia and the up-regulation of pro-inflammatory and degradative factors in synovium were inhibited at 3 weeks and 6 weeks.

CONCLUSIONS

Appropriate PEMF stimulation can reverse the loss of cartilage extracellular matrix, the chondrocytes death, the increased expression of pro-inflammatory and degradative factors in cartilage, the decreased cartilage thickness and synovium inflammation induced by UAC at the early stage of TMJOA to some extent. PEMF stimulation may be a promising method in clinical TMJOA treatment.

Whole-body vibration may not affect bone mineral density and bone turnover in persons with chronic spinal cord injury: A preliminary study

CONTEXT

Spinal-cord injury (SCI) induces bone loss and dramatically increases the risk of fracture.

OBJECTIVES

Determine the effects of whole-body vibration (WBV) on areal bone mineral density (aBMD), whole body composition and bone biological parameters in individuals with chronic-state SCI.

DESIGN

Randomized study.

SETTING

Centre Neurologique PROPARA.

PARTICIPANTS

Fourteen subjects were randomly assigned to a WBV or a control group.

INTERVENTIONS

WBV (20-45 min, 30-45 Hz, 0.5 g) was performed in verticalized persons twice weekly for 6 months.

OUTCOME MEASURES

aBMD was measured by DXA at baseline and 6 months and bone biological parameters at baseline, 1, 3 and 6 months.

RESULTS

No significant aBMD change was found in either the WBV or control group after 6 months of follow-up. Similarly, periostin, sclerostin and bone turnover markers remained relatively stable throughout follow-up and no difference in variation was observed within-group and between groups. Except for whole-body fat mass, which showed a significant decrease in the WBV group compared to controls, no difference in changes was observed, whatever the localization for fat and lean body mass.

CONCLUSIONS

During the chronic phase, aBMD and bone remodeling reach a new steady state. However, the DXA technique and the bone markers, including sclerostin and periostin, both of which reflect bone cell activity influenced by mechanical strain, showed that the bone tissue of individuals with SCI was insensitive to 6 months of WBV training at the study dose. Nevertheless, results of this preliminary study that was underpowered need to be confirmed and other modalities of WBV may be more effective in improving aBMD of this population.

TRIALS REGISTRATION

N°IDRCB:2011-A00224-37.

Effectiveness of FES-supported leg exercise for promotion of paralysed lower limb muscle and bone health-a systematic review

Leg exercises through standing, cycling and walking with/without FES may be used to preserve lower limb muscle and bone health in persons with physical disability due to SCI. This study sought to examine the effectiveness of leg exercises on bone mineral density and muscle cross-sectional area based on their clinical efficacy in persons with SCI. Several literature databases were searched for potential eligible studies from the earliest return date to January 2022. The primary outcome targeted was the change in muscle mass/volume and bone mineral density as measured by CT, MRI and similar devices. Relevant studies indicated that persons with SCI that undertook FES- and frame-supported leg exercise exhibited better improvement in muscle and bone health preservation in comparison to those who were confined to frame-assisted leg exercise only. However, this observation is only valid for exercise initiated early (i.e., within 3 months after injury) and for ≥30 min/day for ≥ thrice a week and for up to 24 months or as long as desired and/or tolerable. Consequently, apart from the positive psychological effects on the users, leg exercise may reduce fracture rate and its effectiveness may be improved if augmented with FES.

Rehabilitation interventions to modify endocrine-metabolic disease risk in individuals with chronic spinal cord injury living in the community (RIISC): A systematic search and review of prospective cohort and case-control studies

CONTEXT

Endocrine-metabolic disease (EMD) is associated with functional disability, social isolation, hospitalization and even death in individuals living with a chronic spinal cord injury (SCI). There is currently very low-quality evidence that rehabilitation interventions can reduce EMD risk during chronic SCI. Non-randomized trials and alternative study designs are excluded from traditional knowledge synthesis.

OBJECTIVE

To characterize evidence from level 3-4 studies evaluating rehabilitation interventions for their effectiveness to improve EMD risk in community-dwelling adults with chronic SCI.

METHODS

Systematic searches of MEDLINE PubMed, EMBASE Ovid, CINAHL, Cochrane Database of Systematic Reviews, and PsychInfo were completed. All longitudinal trials, prospective cohort, case-control studies, and case series evaluating the effectiveness of rehabilitation/therapeutic interventions to modify/associate with EMD outcomes in adults with chronic SCI were eligible. Two authors independently selected studies and abstracted data. Mean changes from baseline were reported for EMD outcomes. The Downs and Black Checklist was used to rate evidence quality.

RESULTS

Of 489 articles identified, 44 articles (N = 842) were eligible for inclusion. Individual studies reported statistically significant effects of electrical stimulation-assisted training on lower-extremity bone outcomes, and the combined effects of exercise and dietary interventions to improve body composition and cardiometabolic biomarkers (lipid profiles, glucose regulation). In contrast, there were also reports of no clinically important changes in EMD outcomes, suggesting lower quality evidence (study bias, inconsistent findings).

CONCLUSION

Longitudinal multicentre pragmatic studies involving longer-term exercise and dietary intervention and follow-up periods are needed to fully understand the impact of these rehabilitation approaches to mitigate EMD risk. Our broad evaluation of prospective cohort and case-control studies provides new perspectives on alternative study designs, a multi-impairment paradigm approach of studying EMD outcomes, and knowledge gaps related to SCI rehabilitation.

Low frequency pulsed electromagnetic fields exposure alleviate the abnormal subchondral bone remodeling at the early stage of temporomandibular joint osteoarthritis

BACKGROUND

Temporomandibular joint osteoarthritis (TMJOA) is characterized by abnormal subchondral bone remodeling and cartilage degeneration. As a non-invasive biophysical technology, pulsed electromagnetic field (PEMF) treatment has been proven to be efficient in promoting osteogenesis. However, the potential bone protective effect and mechanism of PEMF on abnormal subchondral bone remodeling in TMJOA are unknown.

METHODS

Unilateral anterior crossbite (UAC) was used to create TMJOA model in rats, and 17β-estradiol (E₂) were injected daily to mimic patients with high-physiological levels of estrogen. Mouse osteoblast-like MC3T3-E1 cells treated with recombinant murine IL-1β was used to establish inflammatory environment in vitro. The treatment group were subjected to PEMF (2.0mT, 15 Hz, 2 h/d). Micro-CT scanning, histological staining, real-time PCR and western blotting assays were preformed to observe the changes in the subchondral bone.

RESULTS

Abnormal resorption of subchondral bone induced by UAC, characterized by decreased bone mineral density, increased osteoclast activity and expression of osteoclast-related factors (RANKL) and down-regulated expression of osteogenesis-related factors (OPG, ALP, Runx2 and OCN) at the early stage, could be reversed by PEMF exposure, which was similar to the effect of estrogen. In addition, PEMF exposure and E₂ supplement may have a synergistic effect to some extent. Moreover, PEMF exposure could promote the ALP activity and osteogenic mineralization ability of MC3T3-E1 cells. PEMF promoted the expression of factors related to Wnt/β-Catenin signal pathway both in vivo and in vitro.

CONCLUSIONS

Appropriate PEMF exposure have a protective effect on subchondral bone in TMJOA at early stage, in which canonical Wnt/β-Catenin pathway may be involved. PEMF may be a promising biophysical approach for early intervention of TMJOA in clinic.

Sporting activity does not fully prevent bone demineralization at the impaired hip in athletes with amputation

There is lack of information about bone mineralization at the lumbar spine and bilateral hips of athletes with unilateral lower limb amputation. The present study assessed for the first time the areal bone mineral density at the lumbar spine and at the hip of the able and impaired leg by means of Dual-Energy X-Ray Absorptiometry using a large sample (N = 40) of male athletes. Results showed that bone demineralization in athletes with unilateral lower limb amputation is found at the impaired hip but not at the lumbar spine and may therefore be site-specific. The extent of hip demineralization was influenced by the level of amputation, with about 80% of athletes with above knee amputation and 10% of athletes with below knee amputation showing areal bone mineral density below the expected range for age. Nevertheless, a reduced percentage of fat mass and a lower fat-to-lean mass ratio in the residual impaired leg as well as a greater amount of weekly training was positively associated with bone mineralization at the impaired hip (partial correlation coefficients = 0.377–0.525, p = 0.040–0.003). Results showed that participation in adapted sport has a positive effect on bone health in athletes with unilateral lower limb amputation but is not sufficient to maintain adequate levels of bone mineralization at the impaired hip in athletes with above-knee amputation. Accordingly, physical conditioners should consider implementing sporting programs, according to the severity of the impairment, aimed at improving bone mineralization at the impaired hip and improve body composition in the residual impaired leg.

Inflammaging and bone loss in a rat model of spinal cord injury

Spinal cord injury (SCI) results in significant loss of sublesional bone, adding to the comorbidity of SCI with an increased risk of fracture and post-fracture complications. Unfortunately, the effect of SCI on skeletal health is also likely to rise as the average age of SCI has increased and there are well-known negative effects of age on bone. To date, however, the impact of age and age-associated inflammation (inflammaging) on skeletal health after SCI remains largely unknown. To address this, we compared bone parameters in young (3 month) and middle-aged (9 month) male and female rats with a moderate thoracic contusion injury, to age and sex matched sham-operated controls. Skeletal parameters, locomotor function and serum cytokine levels were assessed at both subchronic (30 days) and chronic (180 days) time points post injury. We hypothesized that SCI would lead to a dramatic loss of bone immediately after injury in all SCI-groups, with inflammaging leading to greater loss in middle-aged SCI rats. We also predicted that while younger rats may re-establish bone properties in more chronic phases of SCI, middle-aged rats would not. Supporting these hypothesis, trabecular bone volume was significantly lower in male and young female SCI rats early after injury. Contrary to our hypothesis, however, there was greater loss of trabecular bone volume, relative to age-matched shams, in young compared to middle-aged SCI rats with no effects of SCI on trabecular bone volume in middle-aged female rats. Moreover, despite recovery of weight-supported locomotor activity, bone loss persisted into the chronic phase of injury for the young rats. Bone formation rates were lower in young male SCI rats, regardless of the time since injury, while both young and middle-aged female SCI rats had lower bone formation in the subchronic but not chronic phase of SCI. In middle-aged rats, SCI-induced higher osteoclast surfaces, which also persisted into the chronic phase of SCI in middle-aged females. Neither age nor SCI-induced increases in inflammation seemed to be associated with bone loss. In fact, SCI had more dramatic and persistent effects on bone in male rats, while aging and SCI elevated serum cytokines only in female rats. Overall, this study demonstrates SCI-induced loss of bone and altered bone turnover in male and female rats that persists into the chronic phase post-injury. The sex and age dependent variations in bone turnover and serum cytokines, however, underscore the need to further explore both mechanisms and potential therapeutics in multiple demographics.

Bone and non-contractile soft tissue changes following open kinetic chain resistance training and testosterone treatment in spinal cord injury: an exploratory study

Twenty men with spinal cord injury (SCI) were randomized into two 16-week intervention groups receiving testosterone treatment (TT) or TT combined with resistance training (TT + RT). TT + RT appears to hold the potential to reverse or slow down bone loss following SCI if provided over a longer period.

INTRODUCTION

Persons with SCI experience bone loss below the level of injury. The combined effects of resistance training and TT on bone quality following SCI remain unknown.

METHODS

Men with SCI were randomized into 16-week treatments receiving TT or TT + RT. Magnetic resonance imaging (MRI) of the right lower extremity before participation and post-intervention was used to visualize the proximal, middle, and distal femoral shaft, the quadriceps tendon, and the intermuscular fascia of the quadriceps. For the TT + RT group, MRI microarchitecture techniques were utilized to elucidate trabecular changes around the knee. Individual mixed models were used to estimate effect sizes.

RESULTS

Twenty participants completed the pilot trial. A small effect for yellow marrow in the distal femur was indicated as increases following TT and decreases following TT + RT were observed. Another small effect was observed as the TT + RT group displayed greater increases in intermuscular fascia length than the TT arm. Distal femur trabecular changes for the TT + RT group were generally small in effect (decreased trabecular thickness variability, spacing, and spacing variability; increased network area). Medium effects were generally observed in the proximal tibia (increased plate width, trabecular thickness, and network area; decreased trabecular spacing and spacing variability).

CONCLUSIONS

This pilot suggests longer TT + RT interventions may be a viable rehabilitation technique to combat bone loss following SCI.

CLINICAL TRIAL REGISTRATION

Registered with clinicaltrials.gov : NCT01652040 (07/27/2012).

Pulsed Electromagnetic Fields Ameliorate Skeletal Deterioration in Bone Mass, Microarchitecture, and Strength by Enhancing Canonical Wnt Signaling-Mediated Bone Formation in Rats with Spinal Cord Injury

Spinal cord injury (SCI) leads to extensive bone loss and high incidence of low-energy fractures. Pulsed electromagnetic fields (PEMF) treatment, as a non-invasive biophysical technique, has proven to be efficient in promoting osteogenesis. The potential osteoprotective effect and mechanism of PEMF on SCI-related bone deterioration, however, remain unknown. The spinal cord of rats was transected at vertebral level T12 to induce SCI. Thirty rats were assigned to the control, SCI, and SCI+PEMF groups (n = 10). One week after surgery, the SCI+PEMF rats were subjected to PEMF (2.0 mT, 15 Hz, 2 h/day) for eight weeks. Micro-computed tomography results showed that PEMF significantly ameliorated trabecular and cortical bone microarchitecture deterioration induced by SCI. Three-point bending and nanoindentation assays revealed that PEMF significantly improved bone mechanical properties in SCI rats. Serum biomarker and bone histomorphometric analyses demonstrated that PEMF enhanced bone formation, as evidenced by significant increase in serum osteocalcin and P1NP, mineral apposition rate, and osteoblast number on bone surface. The PEMF had no impact, however, on serum bone-resorbing cytokines (TRACP 5b and CTX-1) or osteoclast number on bone surface. The PEMF also attenuated SCI-induced negative changes in osteocyte morphology and osteocyte survival. Moreover, PEMF significantly increased skeletal expression of canonical Wnt ligands (Wnt1 and Wnt10b) and stimulated their downstream p-GSK3β and β-catenin expression in SCI rats. This study demonstrates that PEMF can mitigate the detrimental consequence of SCI on bone quantity/quality, which might be associated with canonical Wnt signaling-mediated bone formation, and reveals that PEMF may be a promising biophysical approach for resisting osteopenia/osteoporosis after SCI in clinics.

A Primary Care Provider's Guide to Bone Health in Spinal Cord-Related Paralysis

Individuals with spinal cord injury/disorder (SCI/D) are at high risk for developing secondary osteoporosis. Bone loss after neurologic injury is multifactorial and is dependent on the time from and extent of neurologic injury. Most bone loss occurs in the first year after complete motor paralysis, and fractures occur most commonly in the distal femur and proximal tibia (paraplegic fracture). The 2019 International Society for Clinical Densitometry Position Statement in SCI establishes that dual-energy X-ray absorptiometry (DXA) can be used to both diagnose osteoporosis and predict lower extremity fracture risk in individuals with SCI/D. Pharmacologic treatments used in primary osteoporosis have mixed results when used for SCI/D-related osteoporosis. Ambulation, standing, and electrical stimulation may be helpful at increasing bone mineral density (BMD) in individuals with SCI/D but do not necessarily correlate with fracture risk reduction. Clinicians caring for individuals with spinal cord-related paralysis must maintain a high index of suspicion for fragility fractures and consider referral for surgical evaluation and management.

Translational Insights into Extremely Low Frequency Pulsed Electromagnetic Fields (ELF-PEMFs) for Bone Regeneration after Trauma and Orthopedic Surgery

The finding that alterations in electrical potential play an important role in the mechanical stimulation of the bone provoked hype that noninvasive extremely low frequency pulsed electromagnetic fields (ELF-PEMF) can be used to support healing of bone and osteochondral defects. This resulted in the development of many ELF-PEMF devices for clinical use. Due to the resulting diversity of the ELF-PEMF characteristics regarding treatment regimen, and reported results, exposure to ELF-PEMFs is generally not among the guidelines to treat bone and osteochondral defects. Notwithstanding, here we show that there is strong evidence for ELF-PEMF treatment. We give a short, confined overview of in vitro studies investigating effects of ELF-PEMF treatment on bone cells, highlighting likely mechanisms. Subsequently, we summarize prospective and blinded studies, investigating the effect of ELF-PEMF treatment on acute bone fractures and bone fracture non-unions, osteotomies, spinal fusion, osteoporosis, and osteoarthritis. Although these studies favor the use of ELF-PEMF treatment, they likewise demonstrate the need for more defined and better controlled/monitored treatment modalities. However, to establish indication-oriented treatment regimen, profound knowledge of the underlying mechanisms in the sense of cellular pathways/events triggered is required, highlighting the need for more systematic studies to unravel optimal treatment conditions.

Prevention and management of osteoporosis and osteoporotic fractures in persons with a spinal cord injury or disorder: A systematic scoping review

Objectives: The primary objective was to review the literature regarding methodologies to assess fracture risk, to prevent and treat osteoporosis and to manage osteoporotic fractures in SCI/D.Study Design: Scoping review.Settings/Participants: Human adult subjects with a SCI/D.Outcome measures: Strategies to identify persons with SCI/D at risk for osteoporotic fractures, nonpharmacological and pharmacological therapies for osteoporosis and management of appendicular fractures.Results: 226 articles were included in the scoping review. Risk of osteoporotic fractures in SCI is predicted by a combination of DXA-defined low BMD plus clinical and demographic characteristics. Screening for secondary causes of osteoporosis, in particular hyperparathyroidism, hyperthyroidism, vitamin D insufficiency and hypogonadism, should be considered. Current antiresorptive therapies for treatment of osteoporosis have limited efficacy. Use of surgery to treat fractures has increased and outcomes are good and comparable to conservative treatment in most cases. A common adverse event following fracture was delayed healing.Conclusions: Most of the research in this area is limited by small sample sizes, weak study designs, and significant variation in populations studied. Future research needs to address cohort definition and study design issues.

Novel instrumented frame for standing exercising of users with complete spinal cord injuries

This paper describes a Functional Electrical Stimulation (FES) standing system for rehabilitation of bone mineral density (BMD) in people with Spinal Cord Injury (SCI). BMD recovery offers an increased quality of life for people with SCI by reducing their risk of fractures. The standing system developed comprises an instrumented frame equipped with force plates and load cells, a motion capture system, and a purpose built 16-channel FES unit. This system can simultaneously record and process a wide range of biomechanical data to produce muscle stimulation which enables users with SCI to safely stand and exercise. An exergame provides visual feedback to the user to assist with upper-body posture control during exercising. To validate the system an alternate weight-shift exercise was used; 3 participants with complete SCI exercised in the system for 1 hour twice-weekly for 6 months. We observed ground reaction forces over 70% of the full body-weight distributed to the supporting leg at each exercising cycle. Exercise performance improved for each participant by an increase of 13.88 percentage points of body-weight in the loading of the supporting leg during the six-month period. Importantly, the observed ground reaction forces are of higher magnitude than other studies which reported positive effects on BMD. This novel instrumentation aims to investigate weight bearing standing therapies aimed at determining the biomechanics of lower limb joint force actions and postural kinematics.

Self-Assisted Standing Enabled by Non-Invasive Spinal Stimulation after Spinal Cord Injury

Neuromodulation of spinal networks can improve motor control after spinal cord injury (SCI). The objectives of this study were to (1) determine whether individuals with chronic paralysis can stand with the aid of non-invasive electrical spinal stimulation with their knees and hips extended without trainer assistance, and (2) investigate whether postural control can be further improved following repeated sessions of stand training. Using a double-blind, balanced, within-subject cross-over, and sham-controlled study design, 15 individuals with SCI of various severity received transcutaneous electrical spinal stimulation to regain self-assisted standing. The primary outcomes included qualitative comparison of need of external assistance for knee and hip extension provided by trainers during standing without and in the presence of stimulation in the same participants, as well as quantitative measures, such as the level of knee assistance and amount of time spent standing without trainer assistance. None of the participants could stand unassisted without stimulation or in the presence of sham stimulation. With stimulation all participants could maintain upright standing with minimum and some (n = 7) without external assistance applied to the knees or hips, using their hands for upper body balance as needed. Quality of balance control was practice-dependent, and improved with subsequent training. During self-initiated body-weight displacements in standing enabled by spinal stimulation, high levels of leg muscle activity emerged, and depended on the amount of muscle loading. Our findings indicate that the lumbosacral spinal networks can be modulated transcutaneously using electrical spinal stimulation to facilitate self-assisted standing after chronic motor and sensory complete paralysis.

Bone changes in the lower limbs from participation in an FES rowing exercise program implemented within two years after traumatic spinal cord injury

Objective: To determine the effect of a functional electrical stimulation (FES) rowing program on bone mineral density (BMD) when implemented within two years after SCI.Design: Prospective.Setting: Health Care Facility.Participants: Convenience sample; four adults with recent (<2 years) traumatic, motor complete SCI (C7-T12 AIS A-B).Intervention: A 90-session FES rowing exercise program; participants attended 30-minute FES training sessions approximately three times each week for the duration of their participation.Outcome Measures: BMD in the distal femur and tibia were measured using peripheral Quantitative Computed Tomography (pQCT) at enrollment (T₀) and after 30 (T₁), 60 (T₂), and 90 (T₃) sessions. Bone stimulus was calculated for each rower at each time point using the average number of weekly loading cycles, peak foot reaction force, and bone mineral content from the previous time point. A regression analysis was used to determine the relationship between calculated bone stimulus and change in femoral trabecular BMD between time points.Results: Trabecular BMD in the femur and tibia decreased for all participants in T_0-1, but the rate of loss slowed or reversed between T_1-2, with little-to-no bone loss for most participants during T_2-3. The calculated bone stimulus was significantly correlated with change in femoral trabecular BMD (P = 0.016; R²= 0.458).Conclusion: Consistent participation in an FES rowing program provides sufficient forces and loading cycles to reduce or reverse expected bone loss at the distal femur and tibia, at least temporarily, in some individuals within two years after SCI.Trial Registration: NCT02008149.

Spinal Cord Injury: How Could Acupuncture Help?

Spinal cord injury (SCI) is one of the most common causes of death and disability worldwide, and it can result in both permanent disability and serial complications in patients. Research shows that patients with SCI complications are often interested in acupuncture for symptomatic relief. Therefore, the issue of physicians advising their patients regarding the use of acupuncture to alleviate SCI complications becomes pertinent. We review and summarize two types of relevant publications: (1) literature concerning acupuncture for SCI and its complications and (2) underlying mechanisms of acupuncture therapy for SCI. Clinical trials and reviews have suggested that acupuncture effectively manages a range of post-SCI complications, including motor and sensory dysfunction, pain, neurogenic bowel and bladder, pressure ulcers, spasticity, and osteoporosis. The effect of acupuncture on post-SCI orthostatic hypotension and sexual dysfunction remains unclear. Decreased oxidative stress, inhibition of inflammation and neuronal apoptosis, regulation of the expression and activity of endogenous biological mediators, and increased regenerative stem cell production are the possible mechanisms of acupuncture therapy for SCI. Although many limitations have been reported in previous studies, given the evidence for the efficacy of acupuncture, we recommend that physicians should support the use of acupuncture therapy for SCI complications.

Overground vs. treadmill-based robotic gait training to improve seated balance in people with motor-complete spinal cord injury: a case report

Background

Robotic overground gait training devices, such as the Ekso, require users to actively participate in triggering steps through weight-shifting movements. It remains unknown how much the trunk muscles are activated during these movements, and if it is possible to transfer training effects to seated balance control. This study was conducted to compare the activity of postural control muscles of the trunk during overground (Ekso) vs. treadmill-based (Lokomat) robotic gait training, and evaluate changes in seated balance control in people with high-thoracic motor-complete spinal cord injury (SCI).

Methods

Three individuals with motor-complete SCI from C7-T4, assumed to have no voluntary motor function below the chest, underwent robotic gait training. The participants were randomly assigned to Ekso-Lokomat-Ekso or Lokomat-Ekso-Lokomat for 10 sessions within each intervention phase for a total of 30 sessions. We evaluated static and dynamic balance control through analysis of center of pressure (COP) movements after each intervention phase. Surface electromyography was used to compare activity of the abdominal and erector spinae muscles during Ekso and Lokomat walking.

Results

We observed improved postural stability after training with Ekso compared to Lokomat during static balance tasks, indicated by reduced COP root mean square distance and ellipse area. In addition, Ekso training increased total distance of COP movements during a dynamic balance task. The trunk muscles showed increased activation during Ekso overground walking compared to Lokomat walking.

Conclusions

Our findings suggest that the Ekso actively recruits trunk muscles through postural control mechanisms, which may lead to improved balance during sitting. Developing effective training strategies to reactivate the trunk muscles is important to facilitate independence during seated balance activity in people with SCI.

Bone loss at the distal femur and proximal tibia in persons with spinal cord injury: imaging approaches, risk of fracture, and potential treatment options

Persons with spinal cord injury (SCI) undergo immediate unloading of the skeleton and, as a result, have severe bone loss below the level of lesion associated with increased risk of long-bone fractures. The pattern of bone loss in individuals with SCI differs from other forms of secondary osteoporosis because the skeleton above the level of lesion remains unaffected, while marked bone loss occurs in the regions of neurological impairment. Striking demineralization of the trabecular epiphyses of the distal femur (supracondylar) and proximal tibia occurs, with the knee region being highly vulnerable to fracture because many accidents occur while sitting in a wheelchair, making the knee region the first point of contact to any applied force. To quantify bone mineral density (BMD) at the knee, dual energy x-ray absorptiometry (DXA) and/or computed tomography (CT) bone densitometry are routinely employed in the clinical and research settings. A detailed review of imaging methods to acquire and quantify BMD at the distal femur and proximal tibia has not been performed to date but, if available, would serve as a reference for clinicians and researchers. This article will discuss the risk of fracture at the knee in persons with SCI, imaging methods to acquire and quantify BMD at the distal femur and proximal tibia, and treatment options available for prophylaxis against or reversal of osteoporosis in individuals with SCI.

Healthcare utilization and associated barriers experienced by wheelchair users: A pilot study

BACKGROUND

More than twenty-five years after passage of the ADA, little remains known about the experiences of wheelchair users when attempting to access health care and how accessibility may influence health care utilization.

OBJECTIVE/HYPOTHESIS

To describe health care utilization among wheelchair users and characterize barriers encountered when attempting to obtain access to health care.

METHODS

An internet-based survey of wheelchair users was conducted. Measures included demographics, condition, socioeconomic status, health care utilization and receipt of preventive services within the past year, physical barriers encountered at outpatient facilities, and satisfaction with care.

RESULTS

Four hundred thirty-two wheelchair users responded to the survey. Nearly all respondents (97.2%) had a primary care appointment within the past year and most reported 3-5 visits to both primary and specialty care providers. Most encountered physical barriers when accessing care (73.8% primary, 68.5% specialty). Participants received most preventive interventions at rates similar to national averages with the exception of Pap tests. Most participants remained clothed for their primary care evaluation (76.1%), and were examined seated in their wheelchair (69.7%). More than half of participants (54.1%) felt they received incomplete care, and 57% believed their physician had no more than a moderate understanding of their disability-specific medical concerns.

CONCLUSIONS

Wheelchair users face persistent barriers to care, may receive less than thorough physical evaluations, receive fewer screenings for cervical cancer, and largely believe they receive incomplete care.

Precision of dual-energy X-ray absorptiometry of the knee and heel: methodology and implications for research to reduce bone mineral loss after spinal cord injury

STUDY DESIGN

Methodological validation of dual-energy x-ray absorptiometry (DXA)-based measures of leg bone mineral density (BMD) based on the guidelines of the International Society for Clinical Densitometry.

OBJECTIVES

The primary objective of this study was to determine the precision of BMD estimates at the knee and heel using the manufacturer provided DXA acquisition algorithm. The secondary objective was to determine the smallest change in DXA-based measurement of BMD that should be surpassed (least significant change (LSC)) before suggesting that a biological change has occurred in the distal femur, proximal tibia and calcaneus.

SETTING

Academic Research Centre, Canada.

METHODS

Ten people with motor-complete SCI of at least 2 years duration and 10 people from the general population volunteered to have four DXA-based measurements taken of their femur, tibia and calcaneus. BMDs for seven regions of interest (RIs) were calculated, as were short-term precision (root-mean-square (RMS) standard deviation (g cm^-2), RMS-coefficient of variation (RMS-CV, %)) and LSC.

RESULTS

Overall, RMS-CV values were similar between SCI (3.63-10.20%, mean=5.3%) and able-bodied (1.85-5.73%, mean=4%) cohorts, despite lower absolute BMD values at each RIs in those with SCI (35%, heel to 54%, knee; P<0.0001). Precision was highest at the calcaneus and lowest at the femur. Except at the femur, RMS-CV values were under 6%.

CONCLUSIONS

For DXA-based estimates of BMD at the distal femur, proximal tibia and calcaneus, these precision values suggest that LSC values >10% are needed to detect differences between treated and untreated groups in studies aimed at reducing bone mineral loss after SCI.

Investigating the status of using lower extremity orthoses recommended to patients with spinal cord injury

STUDY DESIGN

Retrospective descriptive study.

OBJECTIVES

The present study aimed to investigate the rate of using orthosis among spinal cord injury (SCI) patients for whom orthosis was recommended for standing and walking, the relationship between the clinical and demographic characteristics of SCI and the use of orthosis and the reasons for not using orthosis.

SETTING

Ankara Physical Medicine and Rehabilitation Training and Research Hospital, Turkey.

METHODS

The study included 62 SCI patients for whom orthosis was recommended for standing and ambulation. The patients were classified into two groups as individuals using and not using the recommended orthosis every day in order to evaluate the effect of age, gender, residence, duration of disease/recommended duration of orthosis, recommended orthosis, lesion level-degree, lower extremity tonus-range of motion and ambulation level on the frequency of orthosis use.

RESULTS

The orthosis most commonly recommended was hip-knee-ankle-foot orthosis with waist or pelvic belt (45.2%). Of the patients, 25.8% have never used the orthosis. The most common reason for not using the recommended orthosis was the failure to facilitate the daily life activities of the patient (30%), the difficulties in putting them on and taking them off (20%), the belief that it is unnecessary (15%) and the pressure (15%). In addition, the assessed clinical and demographic features were detected as not important risk factors for not using orthosis.

CONCLUSION

At least one out of four patients with SCI do not use the recommended lower extremity orthosis. Selecting eligible patients, patient training and follow-up are important for increased frequency of orthosis usage.

Pulsed electromagnetic field therapy effectiveness in low back pain: A systematic review of randomized controlled trials

Background

Low back pain is a worldwide prevalent musculoskeletal condition in the general population. In this sense, the pulsed electromagnetic fields (PEMF) therapy has shown significant clinical benefits in several musculoskeletal conditions.

Objective

To assess the effectiveness of the PEMF therapy in reducing pain and clinical symptomatology in patients with low back pathological conditions.

Methods

It was performed a comprehensive database search using Pubmed, Scopus, Cochrane Library and PEDro databases to assess the effectiveness of the PEMF therapy in reducing pain and clinical symptomatology in patients with low back pathological conditions. The search was performed from January 2005 to August 2015 and conducted by two independent investigators, which scrutinize the reference list of most relevant studies. The methodological quality was assessed by the PEDro scale and the level of evidence was set according Oxford Center for Evidence-Based Medicine scale.

Results

Six studies were eligible inclusion on the qualitative analysis and five into the quantitative analysis, scoring an overall 6.8 points according the PEDro scale. The studies showed heterogeneity concerning the intervention protocols. Nevertheless, the effect sizes' indicated a clear tendency to reduction of the pain intensity favoring the PEMF groups, reaching a minimal clinically important difference.

Conclusion

PEMF therapy seems to be able to relieve the pain intensity and improve functionality in individuals with low back pain conditions. Further research is needed regarding PEMF effects on the different conditions of low back pain, with standardized protocols, larger samples and adjustment for low back pain confounders in order to achieve stronger conclusions.

Risk factors for osteoporotic fractures in persons with spinal cord injuries and disorders

Clinical risk factors for fracture were explored among Veterans with a spinal cord injury. At the end of 11 years of follow-up, the absolute risk of fracture was approximately 20 %. Among the clinical and SCI-related factors explored, a prior history of fracture was strongly associated with incident fracture.

INTRODUCTION

Few studies to date have comprehensively addressed clinical risk factors for fracture in persons with spinal cord injury (SCI). The purpose of this study was to identify risk factors for incident osteoporotic fractures in persons with a SCI that can be easily determined at the point of care.

METHODS

The Veteran's Affairs Spinal Cord Dysfunction Registry, a national database of persons with a SCI, was used to examine clinical and SCI-related risk factors for fracture. Incident fractures were identified in a cohort of persons with chronic SCI, defined as SCI present for at least 2 years. Cox regression models were used to estimate the risk of incident fractures.

RESULTS

There were 22,516 persons with chronic SCI included in the cohort with 3365 incident fractures. The mean observational follow-up time for the overall sample was 6.2 years (median 6.0, IQR 2.9-11.0). The mean observational follow-up time for the fracture group was 3.9 years (median 3.3, IQR 1.4-6.1) and 6.7 years (median 6.7, IQR 3.1-11.0) for the nonfracture group. By the end of the study, which included predominantly older Veterans with a SCI observed for a relatively short period of time, the absolute (i.e., cumulative hazard) for incident fractures was 0.17 (95%CI 0.14-0.21). In multivariable analysis, factors associated with an increased risk of fracture included White race, traumatic etiology of SCI, paraplegia, complete extent of SCI, longer duration of SCI, use of anticonvulsants and opioids, prevalent fractures, and higher Charlson Comorbidity Indices. Women aged 50 and older were also at higher risk of sustaining an incident fracture at any time during the 11-year follow-up period.

CONCLUSIONS

There are multiple clinical and SCI-related risk factors which can be used to predict fracture in persons with a SCI. Clinicians should be particularly concerned about incident fracture risk in persons with a SCI who have had a previous fracture.

Restoration of Upper Limb Function in an Individual with Cervical Spondylotic Myelopathy using Functional Electrical Stimulation Therapy: A Case Study

Non-traumatic spinal cord pathology is responsible for 25–52% of all spinal cord lesions. Studies have revealed that spinal stenosis accounts for 16–21% of spinal cord injury (SCI) admissions. Impaired grips as well as slow unskilled hand and finger movements are the most common complaints in patients with spinal cord disorders, such as myelopathy secondary to cervical spondylosis. In the past, our team carried out couple of successful clinical trials, including two randomized control trials, showing that functional electrical stimulation therapy (FEST) can restore voluntary reaching and/or grasping function, in people with stroke and traumatic SCI. Motivated by this success, we decided to examine changes in the upper limb function following FEST in a patient who suffered loss of hand function due to myelopathy secondary to cervical spondylosis. The participant was a 61-year-old male who had C3–C7 posterior laminectomy and instrumented fusion for cervical myelopathy. The participant presented with progressive right hand weakness that resulted in his inability to voluntarily open and close the hand and to manipulate objects unilaterally with his right hand. The participant was enrolled in the study ~22 months following initial surgical intervention. Participant was assessed using Toronto Rehabilitation Institute’s Hand Function Test (TRI-HFT), Action Research Arm Test (ARAT), Functional Independence Measure (FIM), and Spinal Cord Independence Measure (SCIM). The pre–post differences in scores on all measures clearly demonstrated improvement in voluntary hand function following 15 1-h FEST sessions. The changes observed were meaningful and have resulted in substantial improvement in performance of activities of daily living. These results provide preliminary evidence that FEST has a potential to improve upper limb function in patients with non-traumatic SCI, such as myelopathy secondary to cervical spondylosis.

Bone Imaging and Fracture Risk after Spinal Cord Injury

Spinal cord injury (SCI) is characterized by marked bone loss and an increased risk of fracture with high complication rate. Recent research based on advanced imaging analysis, including quantitative computed tomography (QCT) and patient-specific finite element (FE) modeling, has provided new and important insights into the magnitude and temporal pattern of bone loss, as well as the associated changes to bone structure and strength, following SCI. This work has illustrated the importance of early therapeutic treatment to prevent bone loss after SCI and may someday serve as the basis for a clinical fracture risk assessment tool for the SCI population. This review provides an update on the epidemiology of fracture after SCI and discusses new findings and significant developments related to bone loss and fracture risk assessment in the SCI population based on QCT analysis and patient-specific FE modeling.

Long-bone fractures in persons with spinal cord injury

STUDY DESIGN

Retrospective data analysis.

OBJECTIVES

To document fracture characteristics, management and related complications in individuals with traumatic spinal cord injury (SCI).

SETTING

Rehabilitation centre for SCI individuals.

METHOD

Patients' records were reviewed. Patients with traumatic SCI and extremity fractures that had occurred after SCI were included. Patient characteristics, fractured bone, fracture localisation, severity and management (operative/conservative), and fracture-related complications were extracted.

RESULTS

A total of 156 long-bone fractures in 107 SCI patients (34 women and 73 men) were identified. The majority of patients were paraplegics (77.6%) and classified as American Spinal Injury Association Impairment Scale A (86.0%). Only the lower extremities were affected, whereby the femur (60.9% of all fractures) was fractured more frequently than the lower leg (39.1%). A total of 70 patients (65.4%) had one fracture, whereas 37 patients (34.6%) had two or more fractures. Simple or extraarticular fractures were most common (75.0%). Overall, 130 (83.3%) fractures were managed operatively. Approximately half of the femur fractures (48.2%) were treated with locking compression plates. In the lower leg, fractures were mainly managed with external fixation (48.8%). Conservative fracture management was applied in 16.7% of the cases and consisted of braces or a well-padded soft cast. Fracture-associated complications were present in 13.5% of the cases but did not differ significantly between operative (13.1%) and conservative (15.4%) fracture management.

CONCLUSION

SCI was associated with simple or extraarticular fractures of the distal femur and the lower leg. Fractures were mainly managed operatively with a low complication rate.

Chronic complications of spinal cord injury

Spinal cord injury (SCI) is a serious medical condition that causes functional, psychological and socioeconomic disorder. Therefore, patients with SCI experience significant impairments in various aspects of their life. The goals of rehabilitation and other treatment approaches in SCI are to improve functional level, decrease secondary morbidity and enhance health-related quality of life. Acute and long-term secondary medical complications are common in patients with SCI. However, chronic complications especially further negatively impact on patients’ functional independence and quality of life. Therefore, prevention, early diagnosis and treatment of chronic secondary complications in patients with SCI is critical for limiting these complications, improving survival, community participation and health-related quality of life. The management of secondary chronic complications of SCI is also important for SCI specialists, families and caregivers as well as patients. In this paper, we review data about common secondary long-term complications after SCI, including respiratory complications, cardiovascular complications, urinary and bowel complications, spasticity, pain syndromes, pressure ulcers, osteoporosis and bone fractures. The purpose of this review is to provide an overview of risk factors, signs, symptoms, prevention and treatment approaches for secondary long-term complications in patients with SCI.

Whole-Body Electromyostimulation to Fight Osteopenia in Elderly Females: The Randomized Controlled Training and Electrostimulation Trial (TEST-III)

Whole-body electromyostimulation (WB-EMS) has been shown to be effective in increasing muscle strength and mass in elderly women. Because of the interaction of muscles and bones, these adaptions might be related to changes in bone parameters. 76 community-living osteopenic women 70 years and older were randomly assigned to either a WB-EMS group (n = 38) or a control group (CG: n = 38). The WB-EMS group performed 3 sessions every 14 days for one year while the CG performed gymnastics containing identical exercises without EMS. Primary study endpoints were bone mineral density (BMD) at lumbar spine (LS) and total hip (thip) as assessed by DXA. After 54 weeks of intervention, borderline nonsignificant intergroup differences were determined for LS-BMD (WB-EMS: 0.6 ± 2.5% versus CG -0.7 ± 2.5%, P = .051) but not for thip-BMD (WB-EMS: -1.1 ± 1.9% versus CG: -0.8 ± 2.3%, P = .771). With respect to secondary endpoints, there was a gain in lean body mass (LBM) of 1.5% (P = .006) and an increase in grip strength of 8.4% (P = .000) in the WB-EMS group compared to CG. WB-EMS effects on bone are less pronounced than previously reported effects on muscle mass. However, for subjects unable or unwilling to perform intense exercise programs, WB-EMS may be an option for maintaining BMD at the LS.

Osteoporosis in individuals with spinal cord injury

The pathophysiology, clinical considerations, and relevant experimental findings with regard to osteoporosis in individuals with spinal cord injury (SCI) will be discussed. The bone loss that occurs acutely after more neurologically motor complete SCI is unique for its sublesional skeletal distribution and rate, at certain skeletal sites approaching 1% of bone mineral density per week, and its resistance to currently available treatments. The areas of high bone loss include the distal femur, proximal tibia, and more distal boney sites. Evidence from a study performed in monozygotic twins discordant for SCI indicates that sublesional bone loss in the twin with SCI increases for several decades, strongly suggesting that the heightened net bone loss after SCI may persist for an extended period of time. The increased frequency of fragility fracture after paralysis will be discussed, and a few risk factors for such fractures after SCI will be examined. Because vitamin D deficiency, regardless of disability, is a relevant consideration for bone health, as well as an easily reversible condition, the increased prevalence of and treatment target values for vitamin D in this deficiency state in the SCI population will be reviewed. Pharmacological and mechanical approaches to preserving bone integrity in persons with acute and chronic SCI will be reviewed, with emphasis placed on efficacy and practicality. Emerging osteoanabolic agents that improve functioning of WNT/β-catenin signaling after paralysis will be introduced as therapeutic interventions that may hold promise.

Possible way to reduce fracture rates in patients with traumatic spinal cord injury?

Lower extremity fractures in men with spinal cord injury (SCI) are a major problem. The use of thiazide diuretics, a simple and safe intervention, may be effective in reducing the risk of fracture in patients with traumatic SCI. Furthermore, thiazide diuretics have an added benefit of reducing kidney stone formation.

Effects of electromyostimulation on muscle and bone in men with acute traumatic spinal cord injury: A randomized clinical trial

OBJECTIVE

To study the effect of 14 weeks of electromyostimulation (EMS) training (47 minutes/day, 5 days/week) on both muscle and bone loss prevention in persons with recent, complete spinal cord injury (SCI).

DESIGN

Prospective, experimental, controlled, single-blind randomized trial with external blind evaluation by third parties.

METHODS

Eight men with recent SCI (8 weeks from injury; ASIA Impairment Scale (AIS) "A") were randomized into the intervention or the control groups. Cross-sectional area of the quadriceps femoris (QF) muscle was quantified using magnetic resonance imaging. Bone mineral density changes were assessed with a dual-energy X-ray absorptiometry. Several bone biomarkers (i.e. total testosterone, cortisol, growth hormone, insulin-growth factor I, osteocalcin, serum type I collagen C-telopeptide), lipid, and lipoprotein profiles were quantified. A standard oral glucose tolerance test was performed before and after the 14-week training. All analyses were conducted at the beginning and after the intervention.

RESULTS

The intervention group showed a significant increase in QF muscle size when compared with the control group. Bone losses were similar in both groups. Basal levels of bone biomarkers did not change over time. Changes in lipid and lipoprotein were similar in both groups. Glucose and insulin peaks moved forward after the training in the intervention group.

CONCLUSIONS

This study indicates that skeletal muscle of patients with complete SCI retains the ability to grow in response to a longitudinal EMS training, while bone does not respond to similar external stimulus. Increases in muscle mass might have induced improvements in whole body insulin-induced glucose uptake.

Mortality after lower extremity fractures in men with spinal cord injury

In the United States, there are over 200,000 men with spinal cord injuries (SCIs) who are at risk for lower limb fractures. The risk of mortality after fractures in SCI is unknown. This was a population-based, cohort study of all male veterans (mean age 54.1; range, 20.3-100.5 years) with a traumatic SCI of at least 2 years' duration enrolled in the Veterans Affairs (VA) Spinal Cord Dysfunction Registry from FY2002 to FY2010 to determine the association between lower extremity fractures and mortality. Mortality for up to 5 years was determined. The lower extremity fracture rate was 2.14 per 100 patient-years at risk for at least one fracture. In unadjusted models and in models adjusted for demographic, SCI-related factors, healthcare use, and comorbidities, there was a significant association between incident lower extremity fracture and increased mortality (hazard ratio [HR], 1.38; 95% confidence interval [CI], 1.17-1.63; HR, 1.36; 95% CI, 1.15-1.61, respectively). In complete SCI, the hazard of death after lower extremity fracture was also increased (unadjusted model: HR, 1.46; 95% CI, 1.13-1.89; adjusted model: HR, 1.32; 95% CI, 1.02-1.71). In fully-adjusted models, the association of incident lower extremity fracture with increased mortality was substantially greater in older men (age ≥50 years) for the entire cohort (HR, 3.42; 95% CI, 2.75-4.25) and for those with complete SCI (HR, 3.13; 95% CI, 2.19-4.45), compared to younger men (age <50 years) (entire cohort: HR, 1.42; 95% CI, 0.94-2.14; complete SCI: HR, 1.71; 95% CI, 0.98-3.01). Every additional point in the Charlson comorbidity index was associated with a 10% increase in the hazard of death in models involving the entire cohort (HR, 1.11; 95% CI, 1.09-1.13) and also in models limited to men with complete SCI (HR, 1.10; 95% CI, 1.06-1.15). These data support the concept that both the fracture itself and underlying comorbidities are drivers of death in men with SCI.

Effectiveness of bisphosphonate analogues and functional electrical stimulation on attenuating post-injury osteoporosis in spinal cord injury patients- a systematic review and meta-analysis

BACKGROUND

Various pharmacologic and non-pharmacologic approaches have been applied to reduce sublesional bone loss after spinal cord injury (SCI), and the results are inconsistent across the studies. The objective of this meta-analysis was to investigate whether the two most-studied interventions, bisphosphonate analogues and functional electrical stimulation (FES), could effectively decrease bone mineral density (BMD) attenuation and/or restore lost BMD in the SCI population.

METHODS

Randomized controlled trials, quasi-experimental studies, and prospective follow-up studies employing bisphosphonates or FES to treat post-SCI osteoporosis were identified in PubMed and Scopus. The primary outcome was the percentage of BMD change from baseline measured by dual-energy X-ray absorptiometry (DEXA) or computed tomography (CT). Data were extracted from four points: the 3rd, 6th, 12th, and 18th month after intervention.

RESULTS

A total of 19 studies were included in the analysis and involved 364 patients and 14 healthy individuals. Acute SCI participants treated with bisphosphonate therapy demonstrated a trend toward less bone loss than participants who received placebos or usual care. A significant difference in BMD decline was noted between both groups at the 3rd and 12th month post-medication. The subgroup analysis failed to show the superiority of intravenous bisphosphonate over oral administration. Regarding FES training, chronic SCI patients had 5.96% (95% CI, 2.08% to 9.84%), 7.21% (95%CI, 1.79% to 12.62%), and 9.56% (95% CI, 2.86% to 16.26%) increases in BMD at the 3rd, 6th, and 12th months post-treatment, respectively. The studies employing FES ≥ 5 days per week were likely to have better effectiveness than studies using FES ≤ 3 days per week.

CONCLUSIONS

Our meta-analysis indicated bisphosphonate administration early following SCI effectively attenuated sublesional bone loss. FES intervention for chronic SCI patients could significantly increase sublesional BMD near the site of maximal mechanical loading.

Mechanotransduction in bone: Intervening in health and disease

Mechanotransduction has been proven to be one of the most significant variables in bone remodeling and its alterations have been shown to result in a variety of bone diseases. Osteoporosis, Paget’s disease, orthopedic disorders, osteopetrosis as well as hyperparathyroidism and hyperthyroidism all comprise conditions which have been linked with deregulated bone remodeling. Although the significance of mechanotransduction for bone health and disease is unquestionable, the mechanisms behind this important process have not been fully understood. This review will discuss the molecules that have been found to be implicated in mechanotransduction, as well as the mechanisms underlying bone health and disease, emphasizing on what is already known as well as new molecules potentially taking part in conveying mechanical signals from the cell surface towards the nucleus under physiological or pathologic conditions. It will also focus on the model systems currently used in mechanotransduction studies, like osteoblast-like cells as well as three-dimensional constructs and their applications among others. It will also examine the role of mechanostimulatory techniques in preventing and treating bone degenerative diseases and consider their applications in osteoporosis, craniofacial development, skeletal deregulations, fracture treatment, neurologic injuries following stroke or spinal cord injury, dentistry, hearing problems and bone implant integration in the near future.

Ambulation and spinal cord injury

Walking is possible for many patients with a spinal cord injury. Avenues enabling walking include braces, robotics and FES. Among the benefits are improved musculoskeletal and mental health, however unrealistic expectations may lead to negative changes in quality of life. Use rigorous assessment standards to gauge the improvement of walking during the rehabilitation process, but also yearly. Continued walking after discharge may be limited by challenges, such as lack of accessibility in and outside the home, and complications, such as shoulder pain or injuries from falls. It is critical to determine the risks and benefits of walking for each patient.

Time-course response in serum markers of bone turnover to a single-bout of electrical stimulation in patients with recent spinal cord injury

The objective of the present repeat-measures study was to determine whether plasma serum levels of testosterone, cortisol, osteocalcin or type I collagen C-telopeptide (CT) are acutely affected following an electro-myostimulation (EMS) bout, and their relation to bone mineral density and muscle mass. Ten men with recent (8 weeks) thoracic spinal cord injury (SCI) (ASIA A) and 10 age-matched able-bodied (AB) men performed one EMS bout on the quadriceps femoris muscle. Blood samples were drawn at basal condition, immediately after EMS, and 15 min, 30 min, 24 h and 48 h post-EMS. Muscle cross-sectional area was measured by magnetic resonance imaging. Bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry. In the SCI group, a significant decrease in testosterone, cortisol and CT together with a significant increase in testosterone/cortisol ratio and osteocalcin/CT ratio was observed after EMS. For the AB subjects, only testosterone and CT decreased significantly following EMS. Muscle size was only related to testosterone/cortisol ratio in the SCI sample (R = 0.659, p < 0.05), whereas BMD did not show any relation to any biomarker. Acute EMS in recent spinal cord injured men seems to induce positive effects on bone turnover biomarkers, and anabolic and catabolic hormones.

Imaging-Based Methods for Non-invasive Assessment of Bone Properties Influenced by Mechanical Loading

PURPOSE

To describe the most common in vivo imaging-based research tools used to assess bone properties that are influenced by mechanical loading associated with exercise, habitual physical activity, or disease states. Bone is a complex metabolically active tissue that adapts to changes in mechanical loading by altering the amount and spatial organization of mineral.

METHOD

Using a narrative review design, the authors provide an overview of bone biology and biomechanics to emphasize the importance of bone size scale, porosity, and degree of mineralization when interpreting measures acquired using quantitative ultrasound (QUS), dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI), and finite element analysis (FEA). For each imaging modality, basic imaging principles, typical outcome measures associated with changes in mechanical loading, and salient features for physiotherapists are described.

MAIN RESULTS

While each imaging modality has strengths and limitations, currently CT-based methods are best suited for determining the effects of mechanical loading on bone properties-particularly in the peripheral skeleton.

CONCLUSIONS

Regardless of the imaging technology used, the physiotherapist must carefully consider the assumptions of the imaging-based method, the clinical context, the nature of the change in mechanical loading, and the expected time course for change in bone properties.

Purpose: To describe the most common in vivo imaging-based research tools used to assess bone properties that are influenced by mechanical loading associated with exercise, habitual physical activity, or disease states. Bone is a complex metabolically active tissue that adapts to changes in mechanical loading by altering the amount and spatial organization of mineral. Method: Using a narrative review design, the authors provide an overview of bone biology and biomechanics to emphasize the importance of bone size scale, porosity, and degree of mineralization when interpreting measures acquired using quantitative ultrasound (QUS), dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI), and finite element analysis (FEA). For each imaging modality, basic imaging principles, typical outcome measures associated with changes in mechanical loading, and salient features for physiotherapists are described. Main Results: While each imaging modality has strengths and limitations, currently CT-based methods are best suited for determining the effects of mechanical loading on bone properties—particularly in the peripheral skeleton. Conclusions: Regardless of the imaging technology used, the physiotherapist must carefully consider the assumptions of the imaging-based method, the clinical context, the nature of the change in mechanical loading, and the expected time course for change in bone properties.

Bone loss following spinal cord injury in a rat model

The current study was undertaken to follow the time course of bone loss in the proximal tibia of rats over several weeks following thoracic contusion spinal cord injury (SCI) of varying severity. It was hypothesized that bone loss would be more pronounced in the more severely injured animals, and that hindlimb weight bearing would help prevent bone loss. Twenty-six female Sprague-Dawley rats (200-225 g, 6-7 weeks old) received standard thoracic (T9) injuries at energies of 6.25, 12.5, 25, or 50 g-cm. The rats were scored weekly for hindlimb function during locomotion. At 0, 2 or 3, and 8 weeks, high-resolution micro-CT images of each right tibia were obtained. Mechanical indentation testing was done to measure the compressive strength of the cancellous bone structure. The 6.25 g-cm group showed near normal locomotion, the 12.5 and 25 g-cm groups showed the ability to frequently or occasionally generate weight-supported plantar steps, respectively, and the 50 g-cm group showed only movement without weight-supported plantar stepping. The 6.25, 12.5 and 25 g-cm groups remained at the same level of bone volume fraction (cancBV/TV=0.24±0.07), while the 50 g-cm group experienced severe bone loss (67%), resulting in significantly lower (p<0.05) bone volume fraction (cancBV/TV=0.11±0.05) at 8 weeks. Proximal tibia cancellous bone strength was reduced by approximately 50% in these severely injured rats. Instead of a linear proportionality between injury severity and bone loss, there appears to be a distinct functional threshold, marked by occasional weight-supported stepping, above which bone loss does not occur.

Bone mineral density in spinal cord injury: an evaluation of the distal femur

Osteoporosis (OP) in spinal cord injury (SCI) patients is a secondary process in which numerous factors are involved. Diagnosing OP and the threshold for fractures in this population, based on bone mineral density (BMD) measured by double energy X-ray absorptiometry (DXA), is still a challenge. The aim of this study was to evaluate bone mineral loss by DXA, its relationship with body composition and fracture incidence, in complete paraplegics patients, compared with aged-matched controls; we include a nonstandard bone site, the distal femur, and describe the technical and practical aspects of this procedure. Twenty-five SCI patients were included in the study and 17 subjects as control group. No prior or recent fractures were observed in X-ray analysis. The BMD of all femoral sites was significantly lower in patients than in controls (femoral neck, total femur, and distal femur); no difference was observed between BMD of the lumbar spine of patients and controls. We found inverse relationship between time of SCI and bone mineral mass only for distal femur BMD. We conclude that the distal femur is a more sensitive bone site for assessing bone loss by DXA, in SCI patients, than the proximal femoral sites.

Changes in the structural and material properties of the tibia in patients with spinal cord injury

STUDY DESIGN

A cross-sectional study.

OBJECTIVES

To measure the change of structural and material properties at different sites of the tibia in spinal cord-injured patients using peripheral quantitative computerised tomography (pQCT).

SETTING

Orthopaedic research centre (UK).

METHODS

Thirty-one subjects were measured--eight with acute spinal cord injury (SCI), nine with chronic SCI and fourteen able-bodied controls. pQCT scans were performed at 2% (proximal), 34% (diaphyseal) and 96% (distal) along the tibia from the tibial plateau. Structural measures of bone were calculated, and volumetric bone mineral density (vBMD) was also measured at all three levels. Muscle cross-sectional area was measured at the diaphyseal level.

RESULTS

Structurally, there were changes in the cortical bone; in the diaphysis, the shape of the cross-section changed to offer less resistance to AP bending, and the cross-sectional area of the cortical shell decreased both proximally and distally. There were corresponding changes in vBMD in the anterior aspect of the cortical diaphysis, as well as proximal and distal trabecular bone. Changes in muscle occurred more rapidly than changes in bone.

CONCLUSION

There were clear changes of both structure and material at all three levels of the tibia in chronic SCI patients. These changes were consistent with specific adaptations to reduced local mechanical loading conditions. To assess fracture risk in SCI and also to monitor the effect of therapeutic interventions, the structure of the bone should be considered in addition to trabecular bone mineral density.