Assessment of anthropometric, systemic, and lifestyle factors influencing bone status in the legs of spinal cord injured individuals

Optimal Management of Osteoporosis in the Spinal Cord (Injury) Population

Spinal cord injury (SCI) leads to significant bone loss resulting in osteoporosis and an increased risk of fractures below the level of injury. It is imperative to screen for osteoporosis in all individuals with SCI starting immediately after the acute injury. Although data are limited, clinicians are encouraged to discuss preventative treatment in the acute SCI period and to treat osteoporosis when diagnosed.

Management of Femoral and Tibial Shaft Fractures in Patients With Chronic Spinal Cord Injury

OBJECTIVES

To compare outcomes and complications between nonoperative and operative management of femur and tibia fractures in patients with paraplegia or quadriplegia from chronic spinal cord injury (SCI).

METHODS

DESIGN

Retrospective cohort study.

SETTING

Three Level-1 Trauma centers.

PATIENT SELECTION CRITERIA

All adult patients with paraplegia or quadriplegia due to a chronic SCI with operative or nonoperative treatment of a femoral or tibial shaft fracture from January 1, 2009 through December 31, 2019 were included.

OUTCOME MEASURES AND COMPARISONS

Outcomes collected included range of motion, pain, return to baseline activity, extent of malunion, and treatment complications (infection, pressure ulcers, nonunion, deep vein thrombosis/pulmonary emobolus, stroke, amputation, death). Comparison between operative and nonoperative treatment were made for each outcome.

RESULTS

Fifty-nine patients with acute lower extremity fracture in the setting of chronic SCI fulfilled inclusion criteria with a median age of 46 years in the operative group and 47 years in the nonoperative group. Twelve patients (70.6%) in the nonoperative group were male with 32 (76.2%) male patients in the operative group. Forty-six patients (78%) presented as low energy trauma. Differences were seen between operative and nonoperative management for pressure ulcers (19% vs. 52.9%, P = 0.009) and mean Visual Analog Scale pain score at first follow-up (1.19 vs. 3.3, P = 0.03). No difference was seen for rates of infection, nonunion, deep vein thrombosis/pulmonary emobolus, stroke, amputation, death, return to baseline activity, and range of motion.

CONCLUSIONS

Tibial and femoral shaft fractures commonly resulted from low energy mechanisms in patients with chronic SCI. Operative treatment seemed to decrease morbidity in these patients via lowered rates of pressure ulcers and decreased pain compared with nonoperative management.

LEVEL OF EVIDENCE

Therapeutic, Level III. See Instructions for Authors for a complete description of levels of evidence.

Characteristics Associated with Bone Loss after Spinal Cord Injury: Implications for Hip Region Vulnerability

BACKGRUOUND

In individuals with spinal cord injury (SCI), bone loss progresses rapidly to the area below the level of injury, leading to an increased risk of fracture. However, there are limited data regarding SCI-relevant characteristics for bone loss and the degree of bone loss in individuals with SCI compared with that in non-SCI community-dwelling adults.

METHODS

Data from men with SCI who underwent dual-energy X-ray absorptiometry at the National Rehabilitation Center (2008 to 2020) between 12 and 36 months after injury were collected and analyzed. Community-dwelling men were matched 1:1 for age, height, and weight as the control group, using data from the Korea National Health and Nutrition Examination Survey (KNHANES, 2008 to 2011).

RESULTS

A comparison of the SCI and the matched control group revealed significantly lower hip region T-scores in the SCI group, whereas the lumbar spine T-score did not differ between groups. Among the 113 men with SCI, the paraplegia group exhibited significantly higher Z-scores of the hip region than the tetraplegia group. Participants with motor-incomplete SCI showed relatively preserved Z-scores of the hip region compared to those of the lumbar region. Moreover, in participants with SCI, the percentage of skeletal muscle displayed a moderate positive correlation with femoral neck Z-scores.

CONCLUSION

Men with SCI exhibited significantly lower bone mineral density of the hip region than community-dwelling men. Paraplegia rather than tetraplegia, and motor incompleteness rather than motor completeness were protective factors in the hip region. Caution for loss of skeletal muscle mass or increased adiposity is also required.

Bone Mineral Loss at the Distal Femur and Proximal Tibia Following Spinal Cord Injury in Men and Women

PURPOSE

Spinal cord injury (SCI) causes rapid bone loss and increases risk of fragility fractures in the lower extremities. The majority of individuals with SCI are men, and few studies have investigated sex as a biological variable in SCI-induced osteoporosis. This cross-sectional study aimed to quantify sex-specific differences in bone mineral following SCI.

METHODS

Quantitative computed tomography (QCT) scans of the distal femur and proximal tibia were obtained at baseline of one of four clinical trials enrolling people who sustained SCI 1 month to 50 years prior to recruitment. Bone volume (BV), bone mineral content (BMC), bone mineral density (BMD), and bending strength index (BSI) were quantified in the integral, trabecular, and cortical bone in the epiphysis, metaphysis and diaphysis. Scans from 106 men and 31 women were analyzed to measure sex-specific effects on bone loss over time post-SCI.

RESULTS

BMC and BSI declined exponentially as a function of time post-SCI and were best described by separate decay curves for men and women. Women had BV, BMC, and BSI at 58-77% that of men in the acute and plateau phases, with both sexes showing similar rates of loss as a function of time post-SCI. Trabecular BMD was best described as an exponential decay versus time post-SCI, with no sex-specific differences.

CONCLUSIONS

Due to consistently lower BV, BMC, and BSI, women may be more susceptible to fractures after SCI than men.

The impact of rehabilitation in bone loss management of patients with spinal cord injury: A systematic review

BACKGROUND

Spinal cord injury (SCI) is a disabling condition characterized by multilevel skeletal muscle impairment and rapid cortical and trabecular bone loss. Rehabilitation is a cornerstone of the long-term management of patients with SCI; however, the optimal rehabilitation strategy for improving bone health has not been fully characterized.

OBJECTIVE

To characterize the current evidence supporting different rehabilitation interventions improving bone health in patients with SCI.

METHODS

On November 17th, 2022, five databases (PubMed, Scopus, Web of Science, Cochrane, and PEDro) were systematically searched for randomized controlled trials (RCTs) assessing SCI patients undergoing rehabilitation interventions. The primary outcomes were bone macroscopical effects. Secondary outcomes were changes in bone metabolisms and functional outcomes.

RESULTS

Out of 499 records, 11 RCTs met the eligibility criteria and were included. Electrical stimulation combined with physical exercise was assessed by 5 studies, standing intervention was assessed by 3 studies, vibration was assessed by 1 study, ultrasound therapy was assessed by 1 study, and electroacupuncture combined with a pulsed magnetic field was assessed by 1 study. The rehabilitation intervention was administered combined with pharmacological treatment (3 studies) or alone (8 studies). Positive effects in terms of BMD were reported by 3 studies. The quality assessment revealed some concerns in 9 out of 11 studies, in accordance with the Cochrane Risk of Bias assessment - version 2.

CONCLUSION

Our data suggest that multicomponent interventions including rehabilitation might be considered a suitable option to improve bone health management in SCI patients. Further studies are mandatory to characterize the optimal combination of non-pharmacological interventions reducing bone loss and improving the risk of fractures in patients with SCI.

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.

The Outcomes of Robotic Rehabilitation Assisted Devices Following Spinal Cord Injury and the Prevention of Secondary Associated Complications

Spinal cord injuries (SCIs) have major consequences on the patient’s health and life. Voluntary muscle paralysis caused by spinal cord damage affects the patient’s independence. Following SCI, an irreversible motor and sensory deficit occurs (spasticity, muscle paralysis, atrophy, pain, gait disorders, pain). This pathology has implications on the whole organism: on the osteoarticular, muscular, cardiovascular, respiratory, gastrointestinal, genito-urinary, skin, metabolic disorders, and neuro-psychic systems. The rehabilitation process for a subject having SCIs can be considered complex, since the pathophysiological mechanism and biochemical modifications occurring at the level of spinal cord are not yet fully elucidated. This review aims at evaluating the impact of robotic-assisted rehabilitation in subjects who have suffered SCI, both in terms of regaining mobility as a major dysfunction in patients with SCI, but also in terms of improving overall fitness and cardiovascular function, respiratory function, as well as the gastrointestinal system, bone density and finally the psychosocial issues, based on multiple clinical trials, and pilot studies. The researched literature in the topic revealed that in order to increase the chances of neuro-motor recovery and to obtain satisfactory results, the combination of robotic therapy, a complex recovery treatment and specific medication is one of the best decisions. Furthermore, the use of these exoskeletons facilitates better/greater autonomy for patients, as well as optimal social integration.

S1 Guidelines on Bone Impairment in Spinal Cord Injury

During the acute and chronic phase of spinal cord injury (SCI) bone turnover and structure are affected. Bone mineral density of lower limbs is decreased up to 28%-50% below that of age-matched peers at 12-18 mo post injury. Coexisting secondary etiologies of osteoporosis may be present, and during ageing additional loss of bone occurs. All these compose a complex canvas of bone impairment after spinal cord injury and make the therapeutical approach challenging. The risk of fragility fractures is increased after the 2nd decade post SCI affecting the functionality and quality of life of individuals with SCI. Diagnostic flaws, lack of a ranking system to categorize the degree of bone impairment similar to the one of World Health Organization, and evidence-based clinical guidelines for management in SCI requires interdisciplinary cooperation and appropriate planning of future research and interventions. Spinal Cord Section of Hellenic Society of Physical Rehabilitation Medicine convened an expert panel working group on bone and spinal cord injury at the Pan-Hellenic Congress 2018 of PRM in Athens Greece, to establish an evidence-based position statement for bone loss in individuals with SCI of traumatic or non-traumatic etiology. This was reviewed by an International Task Force and used to create S1 Guidelines. This first version S1 guideline will work towards to provide help with prophylactic basic osteoporosis therapy diagnostic and therapeutic decisions in acute and chronic phase and rehabilitation countermeasures against osteoporosis related with spinal cord injury.

Heterogeneity in microstructural deterioration following spinal cord injury

BACKGROUND

Modelling and remodelling adapt bone morphology to accommodate strains commonly encountered during loading. If strains exceed a threshold threatening fracture, modelling-based bone formation increases bone volume reducing these strains. If unloading reduces strains below a threshold that inhibits resorption, increased remodelling-based bone resorption reduces bone volume restoring strains, but at the price of compromised bone volume and microstructure. As weight-bearing regions are adapted to greater strains, we hypothesized that microstructural deterioration will be more severe than at regions commonly adapted to low strains following spinal cord injury.

METHODS

We quantified distal tibial, fibula and radius volumetric bone mineral density (vBMD) using high-resolution peripheral quantitative computed tomography in 31 men, mean age 43.5 years (range 23.5-75.0), 12 with tetraplegia and 19 with paraplegia of 0.7 to 18.6 years duration, and 102 healthy age- and sex-matched controls. Differences in morphology relative to controls were expressed as standardized deviation (SD) scores (mean ± SD). Standardized between-region differences in vBMD were expressed as SDs (95% confidence intervals, CI).

RESULTS

Relative to controls, men with tetraplegia had deficits in total vBMD of -1.72 ± 1.38 SD at the distal tibia (p < 0.001) and - 0.68 ± 0.69 SD at distal fibula (p = 0.041), but not at the distal radius, despite paralysis. Deficits in men with paraplegia were -2.14 ± 1.50 SD (p < 0.001) at the distal tibia and -0.83 ± 0.98 SD (p = 0.005) at the distal fibula while distal radial total vBMD was 0.23 ± 1.02 (p = 0.371), not significantly increased, despite upper limb mobility. Comparing regions, in men with tetraplegia, distal tibial total vBMD was 1.04 SD (95%CI 0.07, 2.01) lower than at the distal fibula (p = 0.037) and 1.51 SD (95%CI 0.45, 2.57) lower than at the distal radius (p = 0.007); the latter two sites did not differ from each other. Results were similar in men with paraplegia, but total vBMD at the distal fibula was 1.06 SD (95%CI 0.35, 1.77) lower than at the distal radius (p = 0.004).

CONCLUSION

Microarchitectural deterioration following spinal cord injury is heterogeneous, perhaps partly because strain thresholds regulating the cellular activity of mechano-transduction are region specific.

Lower extremity fractures in patients with spinal cord injury characteristics, outcome and risk factors for non-unions

CONTEXT

Sublesional osteoporosis is an important sequel after spinal cord injury (SCI) resulting in a high incidence of fractures and impaired osseous healing due to altered bone metabolism. The following study aims to identify demographic characteristics and outcome of patients with SCI with lower extremity fractures.

DESIGN

Retrospective observational study.

SETTING

Level-I cross-regional trauma center.

PARTICIPANTS

All patients with SCI suffering from osteoporotic/pathologic fractures during an 11-year-period (01/2003-12/2013) at the Center for Spinal Cord Injuries (Trauma Center Murnau) were analyzed via a chart review.

OUTCOME MEASURES

Demographics, surgical and radiologic outcome as well as complication rate were assessed with a special emphasis on union rates and independent risk factors for non-unions.

RESULTS

We identified 132 patients (105 males) who fulfilled the inclusion criteria. Most of them were paraplegic (n=101) and showed motor complete syndromes (n=119). Supracondylar femur fractures were the most prevalent in this study (n=47). We observed a non-union rate of 15.9% (n=21). The development of pseudarthrosis was associated with the time interval since the initial SCI (P < 0.010), delayed in-patient submission (P < 0.038), fracture classification (P < 0.002) and the localization of the fracture (P < 0.0001). The overall complication rate was 16.7%. All dislocated subtrochanteric femur fractures (Garden III and IV) (n=10) developed a non-union, regardless of their management (conservative or surgical). The following independent predictors for non-unions were identified: fracture localization (P < 0.0002), fracture classification (P < 0.056), and fracture management (P < 0.036).

CONCLUSIONS

Even though modern techniques allow surgical interventions in bones with reduced mineral density, non-unions remain a common complication in patients with SCI. Risk factors for non-unions of lower extremity fractures are identified.

Peripheral Quantitative Computed Tomography: Review of Evidence and Recommendations for Image Acquisition, Analysis, and Reporting, Among Individuals With Neurological Impairment

In 2015, the International Society for Clinical Densitometry (ISCD) position statement regarding peripheral quantitative computed tomography (pQCT) did not recommend routine use of pQCT, in clinical settings until consistency in image acquisition and analysis protocols are reached, normative studies conducted, and treatment thresholds identified. To date, the lack of consensus-derived recommendations regarding pQCT implementation remains a barrier to implementation of pQCT technology. Thus, based on description of available evidence and literature synthesis, this review recommends the most appropriate pQCT acquisition and analysis protocols for clinical care and research purposes, and recommends specific measures for diagnosis of osteoporosis, assigning fracture risk, and monitoring osteoporosis treatment effectiveness, among patients with neurological impairment. A systematic literature search of MEDLINE, EMBASE^©, CINAHL, and PubMed for available pQCT studies assessing bone health was carried out from inception to August 8th, 2017. The search was limited to individuals with neurological impairment (spinal cord injury, stroke, and multiple sclerosis) as these groups have rapid and severe regional declines in bone mass. Of 923 references, we identified 69 that met review inclusion criteria. The majority of studies (n = 60) used the Stratec XCT 2000/3000 pQCT scanners as reflected in our evaluation of acquisition and analysis protocols. Overall congruence with the ISCD Official Positions was poor. Only 11% (n = 6) studies met quality reporting criteria for image acquisition and 32% (n = 19) reported their data analysis in a format suitable for reproduction. Therefore, based on current literature synthesis, ISCD position statement standards and the authors' expertise, we propose acquisition and analysis protocols at the radius, tibia, and femur sites using Stratec XCT 2000/3000 pQCT scanners among patients with neurological impairment for clinical and research purposes in order to drive practice change, develop normative datasets and complete future meta-analysis to inform fracture risk and treatment efficacy evaluation.

Management of Lower Extremity Long-bone Fractures in Spinal Cord Injury Patients

The AO classification system, used as a guide for modern fracture care and fixation, follows a basic philosophy of care that emphasizes early mobility and return to function. Lower extremity long-bone fractures in patients with spinal cord injury often are pathologic injuries that present unique challenges, to which the AO principles may not be entirely applicable. Optimal treatment achieves healing without affecting the functional level of the patient. These injuries often result from low-energy mechanisms in nonambulatory patients with osteopenic bone and a thin, insensate soft-tissue envelope. The complication rate can be high, and the outcomes can be catastrophic without proper care. Satisfactory results can be obtained through various methods of immobilization. Less frequently, internal fixation is applied. In certain cases, after discussion with the patient, amputation may be suitable. Prevention strategies aim to minimize bone loss and muscle atrophy.

MRI measures of fat infiltration in the lower extremities following motor incomplete spinal cord injury: reliability and potential implications for muscle activation

Muscle fat infiltration (MFI) is an expected consequence of incomplete spinal cord injury (iSCI). The MFI magnitude may have clinical value in determining functional recovery. However, there is a lack of understanding of how MFI relates to the volitional muscle activity in people with motor incomplete spinal cord injury (iSCI). Five iSCI and 5 uninjured age-matched control subjects participated in the study. In this preliminary study, we established the reliability of MFI quantification of select lower extremity muscles across different raters. Secondly, we assessed the magnitude and distribution of MFI in the lower legs of iSCI and uninjured control participants. Thirdly, we explored the relationship between MFI in the plantar flexor muscles and the ability to volitionally activate these muscles. High levels of inter-rater reliability were observed. The iSCI group had significantly elevated and a vastly different MFI distribution in the lower leg muscles compared to healthy controls. MFI was negatively correlated with volitional activation in iSCI. Our preliminary results sanction the importance of lower extremity MFI quantification as a potential measure in determining the functional outcomes in iSCI, and the subsequent pathological sequelae.

Dynamic wheelchair seating positions impact cardiovascular function after spinal cord injury

BACKGROUND

Innovative wheelchairs allow individuals to change position easily for comfort and social situations. While these wheelchairs are beneficial in multiple ways, the effects of position changes on blood pressure might exacerbate hypotension and cerebral hypoperfusion, particularly in those with spinal cord injury (SCI) who can have injury to autonomic nerves that regulate cardiovascular control. Conversely, cardiovascular benefits may be obtained with lowered seating. Here we investigate the effect of moderate changes in wheelchair position on orthostatic cardiovascular and cerebrovascular reflex control.

METHODS

Nineteen individuals with SCI and ten neurologically-intact controls were tested in supine and seated positions (neutral, lowered, and elevated) in the Elevation™ wheelchair. Participants with SCI were stratified into two groups by the severity of injury to cardiovascular autonomic pathways. Beat-to-beat blood pressure, heart rate and middle cerebral artery blood flow velocity (MCAv) were recorded non-invasively.

RESULTS

Supine blood pressure and MCAv were reduced in individuals with lesions to autonomic pathways, and declined further with standard seating compared to those with preserved autonomic control. Movement to the elevated position triggered pronounced blood pressure and MCAv falls in those with autonomic lesions, with minimum values significantly reduced compared to the seated and lowered positions. The cumulative duration spent below supine blood pressure was greatest in this group. Lowered seating bolstered blood pressure in those with lesions to autonomic pathways.

CONCLUSIONS

Integrity of the autonomic nervous system is an important variable that affects cardiovascular responses to orthostatic stress and should be considered when individuals with SCI or autonomic dysfunction are selecting wheelchairs.

SPONSORSHIP

This work was supported in part by the Heart and Stroke Foundation of British Columbia and the Yukon (V.E.C).

Muscle Density and Bone Quality of the Distal Lower Extremity Among Individuals with Chronic Spinal Cord Injury

BACKGROUND

Understanding the related fates of muscle density and bone quality after chronic spinal cord injury (SCI) is an important initial step in determining endocrine-metabolic risk.

OBJECTIVE

To examine the associations between muscle density and indices of bone quality at the distal lower extremity of adults with chronic SCI.

METHODS

A secondary data analysis was conducted in 70 adults with chronic SCI (C2-T12; American Spinal Injury Association Impairment Scale [AIS] A-D; ≥2 years post injury). Muscle density and cross-sectional area (CSA) and bone quality indices (trabecular bone mineral density [TbBMD] at the distal tibia [4% site] and cortical thickness [CtTh], cortical area [CtAr], cortical BMD [CtBMD], and polar moment of inertia [PMI] at the tibial shaft [66% site]) were measured using peripheral quantitative computed tomography. Calf lower extremity motor score (cLEMS) was used as a clinical measure of muscle function. Multivariable linear regression analyses were performed to determine the strength of the muscle-bone associations after adjusting for confounding variables (sex, impairment severity [AIS A/B vs AIS C/D], duration of injury, and wheelchair use).

RESULTS

Muscle density was positively associated with TbBMD (b = 0.85 [0.04, 1.66]), CtTh (b = 0.02 [0.001, 0.034]), and CtBMD (b = 1.70 [0.71, 2.69]) (P < .05). Muscle CSA was most strongly associated with CtAr (b = 2.50 [0.12, 4.88]) and PMI (b = 731.8 [161.7, 1301.9]) (P < .05), whereas cLEMS was most strongly associated with TbBMD (b = 7.69 [4.63, 10.76]) (P < .001).

CONCLUSIONS

Muscle density and function were most strongly associated with TbBMD at the distal tibia in adults with chronic SCI, whereas muscle size was most strongly associated with bone size and geometry at the tibial shaft.

Treatment with curcumin alleviates sublesional bone loss following spinal cord injury in rats

This work aimed to investigate the therapeutic effect of curcumin on sublesional bone loss induced by spinal cord injury (SCI) in rats. SCI model in this work was generated in rats by surgical transaction of the cord at the T10-12 level. After the surgery, animals were treated with curcumin (110 mg/kg body mass/day, via oral gavages) for 2 weeks. Treatment of SCI rats with curcumin prevented the reduction of bone mass in tibiae and femurs, preserved bone microstructure including trabecular bone volume fraction, trabecular number, and trabecular thickness in proximal tibiae, and preserved mechanical properties of femoral midshaft. Treatment of SCI rats with curcumin increased osteoblast surface and reduced osteoclast surface in proximal tibiae. Treatment of SCI rats with curcumin increased osteocalcin mRNA expression and reduced mRNA levels of tartrate-resistant acid phosphatase and mRNA ratio of receptor activator of NF-κB ligand/osteoprotegerin in distal femurs. Treatment of SCI rats with curcumin reduced serum and femoral levels of thiobarbituric acid reactive substances. Treatment of SCI rats with curcumin had no significant effect on serum 25(OH)D, but enhanced mRNA and protein expression of vitamin D receptor (VDR) in distal femurs. Treatment of SCI rats with curcumin enhanced mRNA levels of Wnt3a, Lrp5, and ctnnb1 and upregulated protein expression of β-catenin in distal femurs. In conclusions, treatment with curcumin abated oxidative stress, activated VDR, and enhanced Wnt/β-catenin pathway, which might explain its beneficial effect against sublesional bone loss following SCI in rats, at least in part.

Adults with spastic cerebral palsy have lower bone mass than those with dyskinetic cerebral palsy

Adults with cerebral palsy (CP) are known to have low bone mass with an increased risk of fragility fracture. CP is classified into two major types: spastic (pyramidal) and dyskinetic (extrapyramidal). Spastic CP is the most common and is characterized by muscle hypertonicity and impaired neuromuscular control. By contrast, dyskinetic CP is characterized by mixed muscle tone with involuntary movements. The aim of this study was to elucidate the relationship between bone metabolism and subtype of CP. Fifty-eight adults with CP (aged 18 to 49years, mean age 33.2years; 32 men, 26 women) were included in this cross-sectional analysis. Lumbar spine and femoral bone mineral density (BMD) Z-scores were measured. Bone markers, including C-telopeptide of type I collagen (CTx) and osteocalcin (OCN), were also analyzed. Among these participants, 30 had spastic CP and 28 had dyskinetic CP. The Z-scores of lumbar spine BMD did not differ between the two types. However, the Z-scores of femur trochanteric BMD were significantly lower in participants with spastic CP than in those with dyskinetic CP (-1.6±1.2 vs. -0.9±1.1, p<0.05). Seventy-four percent of participants with either type of CP had abnormally elevated CTx, while about 90% of participants showed normal OCN levels. When participants were subclassified into nonambulatory and ambulatory groups, the nonambulatory group had significantly lower BMD in the femur, including the trochanteric and total regions, whether they were spastic or dyskinetic (p<0.05). Because the type of CP affects bone mass, nonambulatory spastic CP participants showed the lowest total hip region BMD among the four groups. These results reveal that reduced weight bearing and immobility related to CP cause a negative bone balance because of increased bone resorption, which leads to a lower bone mass. In addition, hypertonicity of the affected limbs in participants with spastic CP resulted in lower bone mass than in those with dyskinetic CP. Type of CP and degree of ambulatory function in adults with CP should be regarded as important factors affecting bone metabolism.

Impact on bone and muscle area after spinal cord injury

Spinal cord injury (SCI) causes inactivation and consequent unloading of affected skeletal muscle and bone. This cross-sectional study investigated correlations of muscle and bone in spinal cord-injured subjects compared with able-bodied subjects. Thirty-one complete SCI paraplegics were divided according to the neurological level of injury (NLoI) into group A (n=16, above thoracic 7 NLoI, age: 33±16 years, duration of paralysis (DoP): 6±6 years) and group B (n=15, thoracic 8-12, age: 39±14 years, DoP: 5.6±6 years), compared with 33 controls (group C). All were examined with peripheral quantitative computed tomography at 66% of tibia length (bone and muscle area, bone/muscle area ratio). In able-bodied subjects, muscle area was correlated with bone area (P<0.001, r=0.88). Groups A and B differed significantly from the control group in terms of bone and muscle area (P<0.001). In paraplegics, less muscle per unit of bone area (bone/muscle area ratio) was found compared with controls (P<0.001). Bone area was negatively correlated with the DoP in the total paraplegic group (r=-0.66, P<0.001) and groups A and B (r=-0.77, P=0.001 vs r=-0.52, P=0.12, respectively). Muscle area and bone/muscle ratio area correlations in paraplegic groups with DoP were weak. Paraplegic subjects who performed standing and therapeutic walking had significantly higher bone area (P=0.02 and P=0.013, respectively). The relationship between bone and muscle was consistent in able-bodied subjects and it was predictably altered in those with SCI, a clinical disease affecting bone and muscle.

Anatomic changes in the macroscopic morphology and microarchitecture of denervated long bone tissue after spinal cord injury in rats

To study the effects of mechanical loading on bones after SCI, we assessed macro- and microscopic anatomy in rats submitted to passive standing (PS) and electrical stimulation (ES). The study design was based on two main groups of juvenile male Wistar rats with SCI: one was followed for 33 days with therapies starting at day 3 and the other was followed for 63 days with therapies starting at day 33. Both groups were composed of four subgroups (n = 10/group): (1) Sham, (2) SCI, (3) SCI + PS, and (4) SCI + ES. Rehabilitation protocol consisted of a 20-minute session, 3x/wk for 30 days. The animals were sequentially weighed and euthanized. The femur and tibia were assessed macroscopically and microscopically by scanning electronic microscopy (SEM). The SCI rats gained less weight than Sham-operated animals. Significant reduction of bone mass and periosteal radii was observed in the SCI rats, whereas PS and ES efficiently improved the macroscopic parameters. The SEM images showed less and thin trabecular bone in SCI rats. PS and ES efficiently ameliorated the bone microarchitecture deterioration by thickening and increasing the trabeculae. Based on the detrimental changes in bone tissue following SCI, the mechanical loading through weight bearing and muscle contraction may decrease the bone loss and restore the macro- and microanatomy.

Active-resisted stance modulates regional bone mineral density in humans with spinal cord injury

OBJECTIVE

In people with spinal cord injury (SCI), active-resisted stance using electrical stimulation of the quadriceps delivered a therapeutic stress to the femur (∼150% of body weight) and attenuated bone mineral density (BMD) decline. In standard densitometry protocols, BMD is averaged over the entire bone cross-section. An asymmetric adaptation to mechanical load may be masked by non-responding regions. The purpose of this study was to test a novel method to assess regional BMD of the femur in individuals with SCI. We hypothesize that there will be regional bone-sparing changes as a result of active-resisted stance.

DESIGN

Mixed cross-sectional and longitudinal.

SETTING

Research laboratory.

PARTICIPANTS

Twelve individuals with SCI and twelve non-SCI controls.

INTERVENTION

Individuals with SCI experienced active-resisted stance or passive stance for up to 3 years.

OUTCOME MEASURES

Peripheral quantitative computed tomography images from were partitioned so that femur anatomic quadrants could be separately analyzed.

RESULTS

Over 1.5 years, the slope of BMD decline over time was slower at all quadrants for the active-resisted stance limbs. At >2 years of training, BMD was significantly higher for the active-resisted stance group than for the passive stance group (P = 0.007). BMD was preferentially spared in the posterior quadrants of the femur with active-resisted stance.

CONCLUSIONS

A regional measurement technique revealed asymmetric femur BMD changes between passive stance and active-resisted stance. Future studies are now underway to better understand other regional changes in BMD after SCI.

High dose compressive loads attenuate bone mineral loss in humans with spinal cord injury

People with spinal cord injury (SCI) lose bone and muscle integrity after their injury. Early doses of stress, applied through electrically induced muscle contractions, preserved bone density at high-risk sites. Appropriately prescribed stress early after the injury may be an important consideration to prevent bone loss after SCI.

INTRODUCTION

Skeletal muscle force can deliver high compressive loads to bones of people with spinal cord injury (SCI). The effective osteogenic dose of load for the distal femur, a chief site of fracture, is unknown. The purpose of this study is to compare three doses of bone compressive loads at the distal femur in individuals with complete SCI who receive a novel stand training intervention.

METHODS

Seven participants performed unilateral quadriceps stimulation in supported stance [150% body weight (BW) compressive load-"High Dose" while opposite leg received 40% BW-"Low Dose"]. Five participants stood passively without applying quadriceps electrical stimulation to either leg (40% BW load-"Low Dose"). Fifteen participants performed no standing (0% BW load-"Untrained") and 14 individuals without SCI provided normative data. Participants underwent bone mineral density (BMD) assessment between one and six times over a 3-year training protocol.

RESULTS

BMD for the High Dose group significantly exceeded BMD for both the Low Dose and the Untrained groups (p < 0.05). No significant difference existed between the Low Dose and Untrained groups (p > 0.05), indicating that BMD for participants performing passive stance did not differ from individuals who performed no standing. High-resolution CT imaging of one High Dose participant revealed 86% higher BMD and 67% higher trabecular width in the High Dose limb.

CONCLUSION

Over 3 years of training, 150% BW compressive load in upright stance significantly attenuated BMD decline when compared to passive standing or to no standing. High-resolution CT indicated that trabecular architecture was preserved by the 150% BW dose of load.

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 adults disabled through acquired neurological conditions: a review

This article is a review of the changes in bone mineral density (BMD), which occur in a number of acquired neurological conditions resulting in disability. For each of spinal cord injury, stroke, multiple sclerosis, Parkinson's disease, and traumatic brain injury, the following aspects are discussed, where information is available: prevalence of low BMD according to World Health Organization diagnostic categories and recommended diagnostic method, prevalence based on other diagnostic tools, comparison of BMD with a control population, rate of decline of BMD following onset of the neurological condition, factors influencing decline; mechanism of bone loss, and fracture rates. The common risk factors of immobilization and vitamin D deficiency would appear to cross all disability groups, with the most rapid phase of bone loss occurring in the acute and subacute phases of each condition.

Bone and muscle loss after spinal cord injury: organ interactions

Spinal cord injury (SCI) results in paralysis and marked loss of skeletal muscle and bone below the level of injury. Modest muscle activity prevents atrophy, whereas much larger--and as yet poorly defined--bone loading seems necessary to prevent bone loss. Once established, bone loss may be irreversible. SCI is associated with reductions in growth hormone, IGF-1, and testosterone, deficiencies likely to exacerbate further loss of muscle and bone. Reduced muscle mass and inactivity are assumed to be contributors to the high prevalence of insulin resistance and diabetes in this population. Alterations in muscle gene expression after SCI share common features with other muscle loss states, but even so, show distinct profiles, possibly reflecting influences of neuromuscular activity due to spasticity. Changes in bone cells and markers after SCI have similarities with other conditions of unloading, although after SCI these changes are much more dramatic, perhaps reflecting the much greater magnitude of unloading. Adiposity and marrow fat are increased after SCI with intriguing, though poorly understood, implications for the function of skeletal muscle and bone cells.

Longitudinal changes in femur bone mineral density after spinal cord injury: effects of slice placement and peel method

SUMMARY

Surveillance of femur metaphysis bone mineral density (BMD) decline after spinal cord injury (SCI) may be subject to slice placement error of 2.5%. Adaptations to anti-osteoporosis measures should exceed this potential source of error. Image analysis parameters likewise affect BMD output and should be selected strategically in longitudinal studies.

INTRODUCTION

Understanding the longitudinal changes in bone mineral density (BMD) after spinal cord injury (SCI) is important when assessing new interventions. We determined the longitudinal effect of SCI on BMD of the femur metaphysis. To facilitate interpretation of longitudinal outcomes, we (1) determined the BMD difference associated with erroneous peripheral quantitative computed tomography (pQCT) slice placement, and (2) determined the effect of operator-selected pQCT peel algorithms on BMD.

METHODS

pQCT images were obtained from the femur metaphysis (12% of length from distal end) of adult subjects with and without SCI. Slice placement errors were simulated at 3 mm intervals and were processed in two ways (threshold-based vs. concentric peel).

RESULTS

BMD demonstrated a rapid decline over 2 years post-injury. BMD differences attributable to operator-selected peel methods were large (17.3% for subjects with SCI).

CONCLUSIONS

Femur metaphysis BMD declines after SCI in a manner similar to other anatomic sites. Concentric (percentage-based) peel methods may be most appropriate when special sensitivity is required to detect BMD adaptations. Threshold-based methods may be more appropriate when asymmetric adaptations are observed.

Role of peripheral quantitative computed tomography in identifying disuse osteoporosis in paraplegia

OBJECTIVE

Disuse osteoporosis is a major long-term health consequence of spinal cord injury (SCI) that still needs to be addressed. Its management in SCI should begin with accurate diagnosis, followed by targeted treatments in the most vulnerable subgroups. We present data quantifying disuse osteoporosis in a cross-section of the Scottish paraplegic population to identify subgroups with lowest bone mineral density (BMD).

MATERIALS AND METHODS

Forty-seven people with chronic SCI at levels T2-L2 were scanned using peripheral quantitative computed tomography at four tibial sites and two femoral sites, at the Queen Elizabeth National Spinal Injuries Unit, Glasgow (UK). At the distal epiphyses, trabecular BMD (BMDtrab), total BMD, total bone cross-sectional area (CSA) and bone mineral content (BMC) were determined. In the diaphyses, cortical BMD, total bone CSA, cortical CSA and BMC were calculated. Bone, muscle and fat CSAs were estimated in the lower leg and thigh.

RESULTS

BMDtrab decreased exponentially with time since injury at different rates in the tibia and femur. At most sites, female paraplegics had significantly lower BMC, total bone CSA and muscle CSA than male paraplegics. Subjects with lumbar SCI tended to have lower bone values and smaller muscle CSAs than in thoracic SCI.

CONCLUSION

At the distal epiphyses of the tibia and femur, there is generally a rapid and extensive reduction in BMDtrab after SCI. Female subjects, and those with lumbar SCI, tend to have lower bone values than males or those with thoracic SCI, respectively.

Dual energy x-ray absorptiometry of the distal femur may be more reliable than the proximal tibia in spinal cord injury

OBJECTIVE

To evaluate the precision of dual energy x-ray absorptiometry scanning at 2 skeletal sites at the knee (proximal femur and distal tibia) in people with SCI.

DESIGN

Cross-sectional.

SETTING

Veterans Affairs Medical Center.

PARTICIPANTS

Subjects (N=20) with chronic SCI.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Precision as determined by root mean square coefficient of variation (RMS-CV) and root mean square standard deviation (RMS-SD).

RESULTS

At the distal femur the root RMS-CV was 3.01% and the RMS-SD was 0.025g/cm2. At the proximal tibia the RMS-CV was 5.91% and the RMS-SD was 0.030g/cm2.

CONCLUSIONS

Precision at the distal femur is greater than at the proximal tibia and we recommend it as the preferred site for the longitudinal assessment of bone mineral density at the knee in chronic SCI.

Osteoporotic fractures and hospitalization risk in chronic spinal cord injury

Osteoporosis is a well acknowledged complication of spinal cord injury. We report that motor complete spinal cord injury and post-injury alcohol consumption are risk factors for hospitalization for fracture treatment. The clinical assessment did not include osteoporosis diagnosis and treatment considerations, indicating a need for improved clinical protocols.

INTRODUCTION

Treatment of osteoporotic long bone fractures often results in lengthy hospitalizations for individuals with spinal cord injury. Clinical features and factors that contribute to hospitalization risk have not previously been described.

METHODS

Three hundred and fifteen veterans > or = 1 year after spinal cord injury completed a health questionnaire and underwent clinical exam at study entry. Multivariate Cox regression accounting for repeated events was used to assess longitudinal predictors of fracture-related hospitalizations in Veterans Affairs Medical Centers 1996-2003.

RESULTS

One thousand four hundred and eighty-seven hospital admissions occurred among 315 participants, and 39 hospitalizations (2.6%) were for fracture treatment. Median length of stay was 35 days. Fracture-related complications occurred in 53%. Independent risk factors for admission were motor complete versus motor incomplete spinal cord injury (hazard ratio = 3.73, 95% CI = 1.46-10.50). There was a significant linear trend in risk with greater alcohol consumption after injury. Record review indicated that evaluation for osteoporosis was not obtained during these admissions.

CONCLUSIONS

Assessed prospectively, hospitalization in Veterans Affairs Medical Centers for low-impact fractures is more common in motor complete spinal cord injury and is associated with greater alcohol use after injury. Osteoporosis diagnosis and treatment considerations were not part of a clinical assessment, indicating the need for improved protocols that might prevent low-impact fractures and related admissions.

VA-based survey of osteoporosis management in spinal cord injury

OBJECTIVE

Although osteoporosis is common following spinal cord injury (SCI), no guidelines exist for its treatment, diagnosis, or prevention. The authors hypothesized that wide variations in diagnosis and treatment practices result from the absence of guidelines. This study sought to characterize the diagnosis and management practices within the VA health care system for osteoporosis following SCI.

DESIGN

Online survey regarding osteoporosis management in SCI composed of 27 questions designed to gather information on responder demographics, osteoporosis diagnostics, and treatment options.

SETTING

VA health care system.

PARTICIPANTS

VHA National SCI Staff Physicians and VHA National SCI Nurses (total n = 450) were sent an email with an invitation to participate.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Practice patterns were assessed, including factors associated with ordering a clinical workup and prescribing osteoporosis treatment.

RESULTS

The response rate was 28%. Ninety-two prescribing practitioners (physicians, nurse practitioners, and physician assistants) were included in the analysis. Of these respondents, 50 (54%) prescribe medications for SCI-induced bone loss; 39 (42%) prescribe bisphosphonates and 46 (50%) prescribe vitamin D. There were 54 (59%) respondents who routinely order diagnostic tests, including dual energy x-ray absorptiometry scans in 50 (54%). Variations in practice were not explained by age, gender, or years practicing SCI medicine. Many respondents (23%) reported barriers to osteoporosis testing including lack of scanning protocols, cost, wheelchair inaccessibility of scanning facilities, and lack of effective treatment guidelines once osteoporosis is diagnosed.

CONCLUSIONS

Despite an absence of screening and treatment guidelines, more than half of all respondents are actively diagnosing and treating osteoporosis with bisphosphonates within the VA health care setting. These data suggest that evidence-based practice guidelines are necessary to reduce practice variations and improve clinical care for this population.

VA-based survey of osteoporosis management in spinal cord injury

OBJECTIVE

Although osteoporosis is common following spinal cord injury (SCI), no guidelines exist for its treatment, diagnosis, or prevention. The authors hypothesized that wide variations in diagnosis and treatment practices result from the absence of guidelines. This study sought to characterize the diagnosis and management practices within the VA health care system for osteoporosis following SCI.

DESIGN

Online survey regarding osteoporosis management in SCI composed of 27 questions designed to gather information on responder demographics, osteoporosis diagnostics, and treatment options.

SETTING

VA health care system.

PARTICIPANTS

VHA National SCI Staff Physicians and VHA National SCI Nurses (total n = 450) were sent an email with an invitation to participate.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Practice patterns were assessed, including factors associated with ordering a clinical workup and prescribing osteoporosis treatment.

RESULTS

The response rate was 28%. Ninety-two prescribing practitioners (physicians, nurse practitioners, and physician assistants) were included in the analysis. Of these respondents, 50 (54%) prescribe medications for SCI-induced bone loss; 39 (42%) prescribe bisphosphonates and 46 (50%) prescribe vitamin D. There were 54 (59%) respondents who routinely order diagnostic tests, including dual energy x-ray absorptiometry scans in 50 (54%). Variations in practice were not explained by age, gender, or years practicing SCI medicine. Many respondents (23%) reported barriers to osteoporosis testing including lack of scanning protocols, cost, wheelchair inaccessibility of scanning facilities, and lack of effective treatment guidelines once osteoporosis is diagnosed.

CONCLUSIONS

Despite an absence of screening and treatment guidelines, more than half of all respondents are actively diagnosing and treating osteoporosis with bisphosphonates within the VA health care setting. These data suggest that evidence-based practice guidelines are necessary to reduce practice variations and improve clinical care for this population.

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

OBJECTIVE

Review the literature on non-pharmacological prevention and treatment of osteoporosis after spinal cord injury (SCI).

METHODS

PubMed, EMBASE and the Cochrane Controlled Trials Register were searched. All identified papers were read by title, abstract and full-length article when relevant. Hand search of the articles' sources identified additional papers. For included studies, the level of evidence was determined.

RESULTS

No studies conclusively showed an effective intervention. However, there are few randomized controlled trials (RCTs), and those that exist assess interventions and outcome measures that could be improved. Five studies on weight-bearing early post-injury are conflicting, but standing or walking may help retain bone mineral. In the chronic phase, there was no effect of weight bearing (12 studies). One study found that an early commencement of sports after SCI improved bone mineral, and the longer the period of athletic career, the higher the (leg) bone mineral. Early after SCI, there may be some effects of electrical stimulation (ES) (five studies). Chronic-phase ES studies vary (14 studies, including mixed periods after injury), but improvement is seen with longer period of training, or higher frequency or stimulus intensity. Improvements correspond to trabecular bone in the distal femur or proximal tibia. Impact vibration and pulsed electromagnetic fields may have some positive effects, whereas pulsed ultrasound does not. Six studies on the influence of spasticity show inconsistent results.

CONCLUSIONS

Bone mineral should be measured around the knee; the length and intensity of the treatment should be sufficiently long and high, respectively, and should commence early after SCI. If bone mineral is to remain, the stimulation has to be possibly continued for long term. In addition, RCTs are necessary.

Barriers to providing dual energy x-ray absorptiometry services to individuals with spinal cord injury

To assess barriers to bone mineral density testing in individuals with chronic spinal cord injury, a cross-sectional study of 20 individuals with spinal cord injury was conducted with assessment of physical and logistical barriers to dual energy x-ray absorptiometry scanning. We identified several barriers, including scanner design and configuration in the scanning room that limited accessibility, increased typical scanning time, and made additional staff necessary. For dual energy x-ray absorptiometry to become a routine component of ongoing care in spinal cord injury medicine, we recommend the following changes: (1) install ceiling-mounted hydraulic lifts and grab bars to facilitate transfers in the scanning room; (2) increase staffing during scans; (3) increase time allotment for scans; (4) install the scanner in an adequately-sized room; and (5) partner with administrators and staff to raise awareness of access issues faced by individuals with spinal cord injury.

Spinal cord injury causes rapid osteoclastic resorption and growth plate abnormalities in growing rats (SCI-induced bone loss in growing rats)

Spinal cord injury causes severe bone loss. We report osteoclast resorption with severe trabecular and cortical bone loss, decreased bone mineral apposition, and growth plate abnormalities in a rodent model of contusion spinal cord injury. These findings will help elucidate the mechanisms of osteoporosis following neurological trauma.

INTRODUCTION

Limited understanding of the mechanism(s) that underlie spinal cord injury (SCI)-induced bone loss has led to few treatment options. As SCI-induced osteoporosis carries significant morbidity and can worsen already profound disability, there is an urgency to advance knowledge regarding this pathophysiology.

METHODS

A clinically relevant contusion model of experimental spinal cord injury was used to generate severe lower thoracic SCI by weight-drop (10 g x 50 mm) in adolescent male Sprague-Dawley rats. Body weight and gender-matched naïve (no surgery) rats served as controls. Bone microarchitecture was determined by micro-computed tomographic imaging. Mature osteoclasts were identified by TRAP staining and bone apposition rate was determined by dynamic histomorphometry.

RESULTS

At 10 days post-injury we detected a marked 48% decrease in trabecular bone and a 35% decrease in cortical bone at the distal femoral metaphysis by micro-CT. A 330% increase in the number of mature osteoclasts was detected at the growth plate in the injured animals that corresponded with cellular disorganization at the chondro-osseous junction. Appositional growth studies demonstrated decreased new bone formation with a mineralization defect indicative of osteoblast dysfunction.

CONCLUSIONS

Contusion SCI results in a rapid bone loss that is the result of increased bone resorption and decreased bone formation.

Evaluation of Spastic Muscle in Stroke Survivors Using Magnetic Resonance Imaging and Resistance to Passive Motion

OBJECTIVE

To assess the feasibility of using magnetic resonance imaging (MRI) and resistance to passive movement to evaluate spastic muscle.

DESIGN

T2-weighted MRI scans of the upper arm were obtained at rest and after the performance of upper-arm exercise. In addition, resistance to passive movement was measured subjectively (Modified Ashworth Scale [MAS]) and objectively by an isokinetic device while the arm was moved at varying speeds (stretch reflex torque).

SETTING

Research laboratory.

PARTICIPANTS

Six hemiplegic stroke survivors (single group) with spasticity in the elbow flexors and extensors.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Strength, stretch reflex torque, MAS, MRI-derived muscle cross-sectional area (CSA), and transverse relaxation time (T2).

RESULTS

The affected sides exhibited spasticity (as assessed through MAS), with the extensors displaying a range of 0 to 3, and the flexors between 1 and 1+. The affected muscle groups were significantly weaker than the unaffected muscle groups (extensors: 61% less, flexors: 65% less; P< or =.05). The affected CSA of the triceps was 25% smaller than that of the unaffected side (P=.01), but the biceps muscle group was similar (5% less on the affected side, P> or =.05). There was a tendency (P=.07; effect size, .48) for the resting T2 to be higher in affected versus unaffected biceps, but triceps values were similar (P> or =.05). Both muscle groups showed an increase in T2 after exercise ( approximately 30%, P< or =.05); however, the affected sides did not show an increase (P> or =.05). For both muscle groups, the affected side had a greater stretch reflex torque, with the range of torque values being greater than the range of MAS scores.

CONCLUSIONS

MRI and quantitative resistance to passive movement may be useful in the evaluation of spasticity. This is clinically relevant for the development and evaluation of antispasticity treatments.

Peripheral quantitative computed tomography: measurement sensitivity in persons with and without spinal cord injury

OBJECTIVES

To determine (1) the error attributable to external tibia-length measurements by using peripheral quantitative computed tomography (pQCT) and (2) the effect these errors have on scan location and tibia trabecular bone mineral density (BMD) after spinal cord injury (SCI).

DESIGN

Blinded comparison and criterion standard in matched cohorts.

SETTING

Primary care university hospital.

PARTICIPANTS

Eight able-bodied subjects underwent tibia length measurement. A separate cohort of 7 men with SCI and 7 able-bodied age-matched male controls underwent pQCT analysis.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The projected worst-case tibia-length-measurement error translated into a pQCT slice placement error of +/-3 mm. We collected pQCT slices at the distal 4% tibia site, 3 mm proximal and 3 mm distal to that site, and then quantified BMD error attributable to slice placement.

RESULTS

Absolute BMD error was greater for able-bodied than for SCI subjects (5.87 mg/cm(3) vs 4.5 mg/cm(3)). However, the percentage error in BMD was larger for SCI than able-bodied subjects (4.56% vs 2.23%).

CONCLUSIONS

During cross-sectional studies of various populations, BMD differences up to 5% may be attributable to variation in limb-length-measurement error.

Relationship between self- and clinically rated spasticity in spinal cord injury

OBJECTIVES

To assess the relation between self- and clinically rated spasticity in spinal cord injury (SCI) and to determine the extent to which symptoms like pain are included in the patients' self-rating of spasticity.

DESIGN

Part 1: an observational, prospective, cross-sectional study and part 2: an observational, prospective, longitudinal study.

SETTING

Swiss paraplegic center.

PARTICIPANTS

Forty-seven (part 1) and 8 (part 2) persons with spastic SCI (American Spinal Injury Association grade A or B).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Clinical rating of movement-provoked spasticity using the Ashworth Scale; self-rating of general and present spasticity by the subject on a 4-point spasm severity scale and by using a visual analog scale (VAS); and questionnaires asking for antispasticity medication, impact of spasticity on daily life, body segment affected by spasticity, and symptoms associated with its occurrence.

RESULTS

There was a poor correlation (rho=.36) between clinically rated (Ashworth Scale) spasticity and self-rated general spasticity and a modest correlation (rho=.70) between Ashworth Scale and self-rated present spasticity in the cross-sectional study in 47 subjects. Questionnaires showed that symptoms like pain and other sensations were associated by the patients with spasticity. There was a significant, but weak, correlation between VAS and Ashworth Scale in the longitudinal study in 3 of the 8 subjects and nonsignificant correlations in the remaining 5 subjects.

CONCLUSIONS

A single clinical assessment of spasticity is a poor indication of a patient's general spasticity. Clinical measures of muscle tone-related spasticity should be complemented by self-rating that distinguishes muscle tone-related spasticity from spasticity affecting the sensory nervous system.

Osteoporosis after spinal cord injury

Osteoporosis is a known consequence of spinal cord injury (SCI) and occurs in almost every SCI patient. It manifests itself as an increase in the incidence of lower extremity fractures. The pattern of bone loss seen in SCI patients is different from that usually encountered with endocrine disorders and disuse osteoporosis. In general, there is no demineralization in supralesional areas following SCI. Several factors appear to have a major influence on bone mass in SCI individuals, such as the degree of the injury, muscle spasticity, age, sex and duration after injury. At the lumbar spine, bone demineralization remains relatively low compared to that of the long bones in the sublesional area. A new steady state level between bone resorption and formation is reestablished about 2 years after SCI. SCI may not only cause bone loss, but also alter bone structure and microstructure. Trabecular bone is more affected than cortical bone in the SCI population. Numerous clinical series have reported a high incidence ranging from 1 to 34% of lower extremity fractures in SCI patients. The pathogenesis of osteoporosis after SCI remains complex and perplexing. Disuse may play an important role in the pathogenesis of osteoporosis, but neural factors also appear to be important. SCI also leads to impaired calcium and phosphate metabolism and the parathyroid hormone (PTH)-vitamin D axis. Pharmacologic intervention for osteoporosis after SCI includes calcium, phosphate, vitamin D, calcitonin and biphosphonates. However, the concomitant prescription of bone-active drugs for the prevention and treatment of osteoporosis remains low, despite the availability of effective therapies. Functional stimulated exercises may contribute to the prevention of bone loss to some extent. In addition, many unanswered questions remain about the pathogenesis of osteoporosis and its clinical management.

Fracture threshold in the femur and tibia of people with spinal cord injury as determined by peripheral quantitative computed tomography

OBJECTIVE

To determine bone traits of the femur and tibia with peripheral quantitative computed tomography (pQCT) that best distinguish between spinal cord injury (SCI) subjects with and without fractures.

DESIGN

Cross-sectional study.

SETTING

In- and outpatient paraplegic center in Switzerland.

PARTICIPANTS

Ninety-nine motor complete SCI subjects (duration of paralysis, 2 mo-49 y), 21 of whom had sustained fractures of the femur or tibia.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Subjects with SCI were questioned about the occurrence, location, and approximate date of fractures to their lower extremities. Trabecular and cortical bone mineral density (BMD), as well as bone geometric properties of distal epiphyses and midshafts of the femur and tibia, were measured by pQCT.

RESULTS

Trabecular BMD of the femur and tibia distal epiphyses was found to distinguish best subjects with fractures from those without. Fractures occurred in subjects with trabecular BMD of less than 114 mg/cm 3 and less than 72 mg/cm 3 for the femoral and tibial distal epiphysis, respectively (corresponding to 46% and 29% of mean values of an able-bodied reference group). Approximately 50% of the subjects with chronic SCI (defined as time postinjury >5 y for femur data and >7 y for tibia data) had trabecular BMD values above the fracture threshold in the femur and about one third above the fracture threshold in the tibia.

CONCLUSIONS

By using pQCT, it may be possible to identify subjects with SCI who are at risk of sustaining fractures of the femur and tibia through minor trauma.