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1.  Postural responses to anterior and posterior perturbations applied to the upper trunk of standing human subjects 
Experimental Brain Research  2015;234:367-376.
This study concerned the effects of brisk perturbations applied to the shoulders of standing subjects to displace them either forwards or backwards, our aim being to characterise the responses to these disturbances. Subjects stood on a force platform, and acceleration was measured at the level of C7, the sacrum and both tibial tuberosities. Surface EMG was measured from soleus (SOL), tibialis anterior (TA), the hamstrings (HS), quadriceps (QUAD), rectus abdominis (RA) and lumbar paraspinal (PS) muscles. Trials were recorded for each of four conditions: subjects’ eyes open (reference) or closed and on a firm (reference) or compliant surface. Observations were also made of voluntary postural reactions to a tap over the deltoid. Anterior perturbations (mean C7 acceleration 251.7 mg) evoked activity within the dorsal muscles (SOL, HS, PS) with a similar latency to voluntary responses to shoulder tapping. Responses to posterior perturbations (mean C7 acceleration −240.4 mg) were more complex beginning, on average, at shorter latency than voluntary activity (median TA 78.0 ms). There was activation of TA, QUAD and SOL associated with initial forward acceleration of the lower legs. The EMG responses consisted of an initial phasic discharge followed by a more prolonged one. These responses differ from the pattern of automatic postural responses that follow displacements at the level of the ankles, and it is unlikely that proprioceptive afferents excited by ankle movement had a role in the initial responses. Vision and surface properties had only minor effects. Perturbations of the upper trunk evoke stereotyped compensatory postural responses for each direction of perturbation. For posterior perturbations, EMG onset occurs earlier than for voluntary responses.
Electronic supplementary material
The online version of this article (doi:10.1007/s00221-015-4442-2) contains supplementary material, which is available to authorized users.
PMCID: PMC4731437  PMID: 26487178
Posture; Postural reflexes; Stance
2.  Fracture or Vertebral Deformation? 
Vertebral fractures are the most common osteoporotic fractures, both in Europe and in the USA, affecting 25% of women over 50 years of age. Although often mild and asymptomatic, vertebral fractures have a considerable impact both on the quality of life and on the survival of those affected. In order to allow more precise identification of vertebral fractures, various methods have been proposed over the past 20 years, designed to furnish a more or less quantitative assessment of the spine. These methods can be divided into two groups: visual semi-quantitative (SQ) and morphometric quantitative. The SQ method, being based on the reading of radiographs has the advantage, compared to quantitative morphometry, of allowing differential diagnosis between vertebral deformations and vertebral fractures, and between the various causes, benign or malignant, of vertebral fractures, allowing, in uncertain cases, more complex examinations –CT or MRI – to be undertaken. Since vertebral fractures always manifest themselves as deformations of the vertebral body, but not all vertebral deformations are fractures, an “algorithm-based qualitative assessment” (ABQ) was recently developed in order to identify true vertebral fractures. The ABQ is based on two fundamental points: According to the ABQ, a vertebra is fractured only if there is central vertebral endplate depression.The ABQ introduces the concept of short vertebral height (SVH) to indicate vertebra that show reduced height, but no central depression. Cases of SVH are not fractures, but normal variants, growth-related abnormalities (Scheuermann’s disease), or arthrosic abnormalities.
Thus, all mid-thoracic cuneiform deformities without evident depression of the central endplate are considered SVHs by the ABQ method, but often as fractures by the SQ and morphometric methods. In a recent article, it was shown that SVH is not correlated with low BMD, whereas ABQ-defined deformities are closely associated with BMD in the osteoporotic range.
In clinical practice the assessment of vertebral fractures is commonly based on the radiologist’s reading of radiographs, the first essential step in the differential diagnosis of various causes of vertebral deformity.
Given the possibility, using dual-energy X-ray absorptiometry (DEXA), of obtaining images with good spatial resolution, it was recently suggested that the visual examination of these images might be used for the identification of vertebral fractures, a method called “vertebral fracture assessment (VFA)”. One advantage of this diagnostic approach is that it can be performed using low doses of radiation and be associated with the measurement of bone mineral density, thereby allowing, contemporaneously, both a qualitative and a quantitative evaluation of the spine, useful for the correct identification of vertebral fractures. According to the findings of recent studies, VFA shows a good level of agreement (96.3%) with semi-quantitative assessment of radiographs in the classification of vertebrae as normal or deformed. Furthermore, the VFA method has been shown to have excellent negative predictive value (98.0%) in distinguishing subjects with normal vertebrae from those with definite or possible vertebral deformities.
In 2005, the ISCD proposed the following diagnostic pathway for the identification of osteoporotic vertebral fractures in the presence of fracture risk factors: using the VFA method, perform an initial visual assessment of the spine on DEXA images;classify patients as normal if all the vertebrae are clearly visualised and found to be normal;classify patients as fractured in the presence of a moderate or severe fracture, identified using Genant’s SQ method;perform a radiographic examination if, on VFA, not all the vertebrae are visualised, orif one or more mild vertebral deformities are identified;on the radiograph, distinguish fractures from mild, non-fracture deformities;determine the type and severity of the fracture according to the SQ method;use morphometry to confirm the presence and severity of the fracture;over time, monitor the patient at risk of fragility fracture, using VFA as well as DEXA densitometry.
In conclusion, by associating VFA with definition – not only quantitative, but also qualitative – of fractures, it will be possible to identify a greater number of true mild, asymptomatic fractures, which constitute the evidence on which to base a drug treatment geared at preventing the occurrence of new fractures, which would be more severe and disabling. To achieve this, there is nevertheless a need for close collaboration between the clinician who requests the examination and the radiologist whose task it is to provide a report, both qualitative and morphometric, of the image of the spine.
PMCID: PMC3213848
3.  Percutaneous Vertebroplasty for Treatment of Painful Osteoporotic Vertebral Compression Fractures 
Executive Summary
Objective of Analysis
The objective of this analysis is to examine the safety and effectiveness of percutaneous vertebroplasty for treatment of osteoporotic vertebral compression fractures (VCFs) compared with conservative treatment.
Clinical Need and Target Population
Osteoporosis and associated fractures are important health issues in ageing populations. Vertebral compression fracture secondary to osteoporosis is a cause of morbidity in older adults. VCFs can affect both genders, but are more common among elderly females and can occur as a result of a fall or a minor trauma. The fracture may occur spontaneously during a simple activity such as picking up an object or rising up from a chair. Pain originating from the fracture site frequently increases with weight bearing. It is most severe during the first few weeks and decreases with rest and inactivity.
Traditional treatment of painful VCFs includes bed rest, analgesic use, back bracing and muscle relaxants. The comorbidities associated with VCFs include deep venous thrombosis, acceleration of osteopenea, loss of height, respiratory problems and emotional problems due to chronic pain.
Percutaneous vertebroplasty is a minimally invasive surgical procedure that has gained popularity as a new treatment option in the care for these patients. The technique of vertebroplasty was initially developed in France to treat osteolytic metastasis, myeloma, and hemangioma. The indications were further expanded to painful osteoporotic VCFs and subsequently to treatment of asymptomatic VCFs.
The mechanism of pain relief, which occurs within minutes to hours after vertebroplasty, is still not known. Pain pathways in the surrounding tissue appear to be altered in response to mechanical, chemical, vascular, and thermal stimuli after the injection of the cement. It has been suggested that mechanisms other than mechanical stabilization of the fracture, such as thermal injury to the nerve endings, results in immediate pain relief.
Percutaneous Vertebroplasty
Percutaneous vertebroplasty is performed with the patient in prone position and under local or general anesthesia. The procedure involves fluoroscopic imaging to guide the injection of bone cement into the fractured vertebral body to support the fractured bone. After injection of the cement, the patient is placed in supine position for about 1 hour while the cement hardens.
Cement leakage is the most frequent complication of vertebroplasty. The leakages may remain asymptomatic or cause symptoms of nerve irritation through compression of nerve roots. There are several reports of pulmonary cement embolism (PCE) following vertebroplasty. In some cases, the PCE may remain asymptomatic. Symptomatic PCE can be recognized by their clinical signs and symptoms such as chest pain, dyspnea, tachypnea, cyanosis, coughing, hemoptysis, dizziness, and sweating.
Research Methods
Literature Search
A literature search was performed on Feb 9, 2010 using OVID MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cumulative Index to Nursing & Allied Health Literature (CINAHL), the Cochrane Library, and the International Agency for Health Technology Assessment (INAHTA) for studies published from January 1, 2005 to February 9, 2010.
Studies were initially reviewed by titles and abstracts. For those studies meeting the eligibility criteria, full-text articles were obtained and reviewed. Reference lists were also examined for any additional relevant studies not identified through the search. Articles with an unknown eligibility were reviewed with a second clinical epidemiologist and then a group of epidemiologists until consensus was established. Data extraction was carried out by the author.
Inclusion Criteria
Study design: Randomized controlled trials (RCTs) comparing vertebroplasty with a control group or other interventions
Study population: Adult patients with osteoporotic vertebral fractures
Study sample size: Studies included 20 or more patients
English language full-reports
Published between Jan 1 2005 and Feb 9, 2010
(eligible studies identified through the Auto Alert function of the search were also included)
Exclusion Criteria
Non-randomized studies
Studies on conditions other than VCF (e.g. patients with multiple myeloma or metastatic tumors)
Studies focused on surgical techniques
Studies lacking outcome measures
Results of Evidence-Based Analysis
A systematic search yielded 168 citations. The titles and the abstracts of the citations were reviewed and full text of the identified citations was retrieved for further consideration. Upon review of the full publications and applying the inclusion and exclusion criteria, 5 RCTs were identified. Of these, two compared vertebroplasty with sham procedure, two compared vertebroplasty with conservative treatment, and one compared vertebroplasty with balloon kyphoplasty.
Randomized Controlled Trials
Recently, the results of two blinded randomized placebo-controlled trials of percutaneous vertebroplasty were reported. These trials, providing the highest quality of evidence available to date, do not support the use of vertebroplasty in patients with painful osteoporotic vertebral compression fractures. Based on the results of these trials, vertebroplasty offer no additional benefit over usual care and is not risk free.
In these trials the treatment allocation was blinded to the patients and outcome assessors. The control group received a sham procedure simulating vertebroplasty to minimize the effect of expectations and to reduce the potential for bias in self-reporting of outcomes. Both trials applied stringent exclusion criteria so that the results are generalizable to the patient populations that are candidates for vertebroplasty. In both trials vertebroplasty procedures were performed by highly skilled interventionists. Multiple valid outcome measures including pain, physical, mental, and social function were employed to test the between group differences in outcomes.
Prior to these two trials, there were two open randomized trials in which vertebroplasty was compared with conservative medical treatment. In the first randomized trial, patients were allowed to cross over to the other arm and had to be stopped after two weeks due to the high numbers of patients crossing over. The other study did not allow cross over and recently published the results of 12 months follow-up.
The following is the summary of the results of these 4 trials:
Two blinded RCTs on vertebroplasty provide the highest level of evidence available to date. Results of these two trials are supported by findings of an open randomized trial with 12 months follow-up. Blinded RCTs showed:
No significant differences in pain scores of patients who received vertebroplasty and patients who received a sham procedure as measured at 3 days, 2 weeks and 1 month in one study and at 1 week, 1 month, 3 months, and 6 months in the other.
The observed differences in pain scores between the two groups were neither statistically significant nor clinically important at any time points.
The above findings were consistent with the findings of an open RCT in which patients were followed for 12 months. This study showed that improvement in pain was similar between the two groups at 3 months and were sustained to 12 months.
In the blinded RCTs, physical, mental, and social functioning were measured at the above time points using 4-5 of the following 7 instruments: RDQ, EQ-5D, SF-36 PCS, SF-36 MCS, AQoL, QUALEFFO, SOF-ADL
There were no significant differences in any of these measures between patients who received vertebroplasty and patients who received a sham procedure at any of the above time points (with a few exceptions in favour of control intervention).
These findings were also consistent with the findings of an open RCT which demonstrated no significant between group differences in scores of ED-5Q, SF-36 PCS, SF 36 MCS, DPQ, Barthel, and MMSE which measure physical, mental, and social functioning (with a few exceptions in favour of control intervention).
One small (n=34) open RCT with a two week follow-up detected a significantly higher improvement in pain scores at 1 day after the intervention in vertebroplasty group compared with conservative treatment group. However, at 2 weeks follow-up, this difference was smaller and was not statistically significant.
Conservative treatment was associated with fewer clinically important complications
Risk of new VCFs following vertebroplasty was higher than those in conservative treatment but it requires further investigation.
PMCID: PMC3377535  PMID: 23074396
4.  Difference in the Electromyographic Onset of the Deep and Superficial Multifidus during Shoulder Movement while Standing 
PLoS ONE  2015;10(4):e0122303.
Based on the current literature, it remains unclear whether electromyographic onset of the deep fibers of the multifidus (DM) is dependent on the direction of shoulder movement and the position of the center of foot pressure (CFP). In the present study, we re-examined the electromyographic onset of the DM during shoulder flexion and extension and investigated the influence of the CFP position before arm movement. Intramuscular and surface electrodes recorded the electromyographic onset of the DM, superficial fibers of the multifidus (SM), rectus abdominis, and anterior and posterior deltoid. Eleven healthy participants performed rapid, unilateral shoulder flexion and extension in response to audio stimuli at three CFP positions: quiet standing, extreme forward leaning, and extreme backward leaning. It was found that the electromyographic onset of the DM and SM relative to the deltoid was dependent on the direction of arm movement. Additionally, of all electromyographic onsets recorded, only that of the DM occurred earlier in the extreme forward leaning position than in the extreme backward leaning position during shoulder flexion. These results suggest that the electromyographic onset of DM was influenced by the biomechanical disturbance such as shoulder movement and CFP position.
PMCID: PMC4388474  PMID: 25850066
5.  Ethnic difference of clinical vertebral fracture risk 
Osteoporosis International  2011;23(3):879-885.
Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. This study observed that Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians, but the vertebral fracture rates were higher, resulting in a high vertebral-to-hip fracture ratio. As a result, estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate.
Vertebral fractures are the most common osteoporotic fractures. Data on the vertebral fracture risk in Asia remain sparse. The aim of this study was to report the incidence of clinical vertebral fractures among the Chinese and to compare the vertebral-to-hip fracture risk to other ethnic groups.
Four thousand, three hundred eighty-six community-dwelling Southern Chinese subjects (2,302 women and 1,810 men) aged 50 or above were recruited in the Hong Kong Osteoporosis Study since 1995. Baseline demographic characteristics and medical history were obtained. Subjects were followed annually for fracture outcomes with a structured questionnaire and verified by the computerized patient information system of the Hospital Authority of the Hong Kong Government. Only non-traumatic incident hip fractures and clinical vertebral fractures that received medical attention were included in the analysis. The incidence rates of clinical vertebral fractures and hip fractures were determined and compared to the published data of Swedish Caucasian and Japanese populations.
The mean age at baseline was 62 ± 8.2 years for women and 68 ± 10.3 years for men. The average duration of follow-up was 4.0 ± 2.8 (range, 1 to 14) years for a total of 14,733 person-years for the whole cohort. The incidence rate for vertebral fracture was 194/100,000 person-years in men and 508/100,000 person-years in women, respectively. For subjects above the age of 65, the clinical vertebral fracture and hip fracture rates were 299/100,000 and 332/100,000 person-years, respectively, in men, and 594/100,000 and 379/100,000 person-years, respectively, in women. Hong Kong Chinese and Japanese populations have a less dramatic increase in hip fracture rates associated with age than Caucasians. At the age of 65 or above, the hip fracture rates for Asian (Hong Kong Chinese and Japanese) men and women were less than half of that in Caucasians, but the vertebral fracture rate was higher in Asians, resulting in a high vertebral-to-hip fracture ratio.
The incidences of vertebral and hip fractures, as well as the vertebral-to-hip fracture ratios vary in Asians and Caucasians. Estimation of the absolute fracture risk for Asians may need to be readjusted for the higher clinical vertebral fracture rate.
PMCID: PMC3277693  PMID: 21461720
Asian; Chinese; Fracture incidence; Osteoporosis; Vertebral fracture
6.  Deltoid-split or Deltopectoral Approaches for the Treatment of Displaced Proximal Humeral Fractures? 
Proximal humeral fractures are mainly associated with osteoporosis and are becoming more common with the aging of our society. The best surgical approach for internal fixation of displaced proximal humeral fractures is still being debated.
In this prospective randomized study, we aimed to investigate whether the deltoid-split approach is superior to the deltopectoral approach with regard to (1) complication rate; (2) shoulder function (Constant score); and (3) pain (visual analog scale [VAS]) for internal fixation of displaced humeral fractures with a polyaxial locking plate.
We randomized 120 patients with proximal humeral fractures to receive one of these two approaches (60 patients for each approach). We prospectively documented demographic and perioperative data (sex, age, fracture type, hospital stay, operation time, and fluoroscopy time) as well as complications. Followup examinations were conducted at 6 weeks, 6 months, and 12 months postoperatively, including radiological and clinical evaluations (Constant score, activities of daily living, and pain [VAS]). Baseline and perioperative data were comparable for both approaches. The sample size was chosen to provide 80% power, but it reached only 68% as a result of the loss of followups to detect a 10-point difference on the Constant score, which we considered the minimum clinically important difference.
Complications or reoperations between the approaches were not different. Eight patients in the deltoid-split group (14%) needed surgical revisions compared with seven patients in the deltopectoral group (13%; p = 1.00). Deltoid-split and deltopectoral approaches showed similar Constant scores 12 months postoperatively (Deltoid-split 81; 95% confidence interval [CI], 74–87 versus deltopectoral 73; 95% CI, 64–81; p = 0.13), and there were no differences between the groups in terms of pain at 1 year (deltoid-split 1.8; 95% CI, 1.2–1.4 versus deltopectoral 2.5; 95% CI, 1.7–3.2; p = 0.14). No learning-curve effects were noted; fluoroscopy use during surgery and function and pain scores during followups were similar among the first 30 patients and the next 30 patients treated in each group.
The treatment of proximal humeral fractures with a polyaxial locking plate is reliable using both approaches. For a definitive recommendation for one of these approaches, further studies with appropriate sample size are necessary.
Level of Evidence
Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
PMCID: PMC3971224  PMID: 24326593
7.  Balloon Kyphoplasty 
Executive Summary
To review the evidence on the effectiveness and cost-effectiveness of balloon kyphoplasty for the treatment of vertebral compression fractures (VCFs).
Clinical Need
Vertebral compression fractures are one of the most common types of osteoporotic fractures. They can lead to chronic pain and spinal deformity. They are caused when the vertebral body (the thick block of bone at the front of each vertebra) is too weak to support the loads of activities of daily living. Spinal deformity due to a collapsed vertebral body can substantially affect the quality of life of elderly people, who are especially at risk for osteoporotic fractures due to decreasing bone mass with age. A population-based study across 12 European centres recently found that VCFs have a negative impact on health-related quality of life. Complications associated with VCFs are pulmonary dysfunction, eating disorders, loss of independence, and mental status change due to pain and the use of medications. Osteoporotic VCFs also are associated with a higher rate of death.
VCFs affect an estimated 25% of women over age 50 years and 40% of women over age 80 years. Only about 30% of these fractures are diagnosed in clinical practice. A Canadian multicentre osteoporosis study reported on the prevalence of vertebral deformity in Canada in people over 50 years of age. To define the limit of normality, they plotted a normal distribution, including mean and standard deviations (SDs) derived from a reference population without any deformity. They reported a prevalence rate of 23.5% in women and a rate of 21.5% in men, using 3 SDs from the mean as the limit of normality. When they used 4 SDs, the prevalence was 9.3% and 7.3%, respectively. They also found the prevalence of vertebral deformity increased with age. For people older than 80 years of age, the prevalence for women and men was 45% and 36%, respectively, using 3 SDs as the limit of normality.
About 85% of VCFs are due to primary osteoporosis. Secondary osteoporosis and neoplasms account for the remaining 15%. A VCF is operationally defined as a reduction in vertebral body height of at least 20% from the initial measurement. It is considered mild if the reduction in height is between 20% and 25%; moderate, if it is between 25% and 40%; and severs, if it is more than 40%. The most frequently fractured locations are the third-lower part of the thorax and the superior lumbar levels. The cervical vertebrae and the upper third of the thorax are rarely involved.
Traditionally, bed rest, medication, and bracing are used to treat painful VCFs. However, anti-inflammatory and narcotic medications are often poorly tolerated by the elderly and may harm the gastrointestinal tract. Bed rest and inactivity may accelerate bone loss, and bracing may restrict diaphragmatic movement. Furthermore, medical treatment does not treat the fracture in a way that ameliorates the pain and spinal deformity.
Over the past decade, the injection of bone cement through the skin into a fractured vertebral body has been used to treat VCFs. The goal of cement injection is to reduce pain by stabilizing the fracture. The secondary indication of these procedures is management of painful vertebral fractures caused by benign or malignant neoplasms (e.g., hemangioma, multiple myeloma, and metastatic cancer).
The Technology
Balloon kyphoplasty is a modified vertebroplasty technique. It is a minimally invasive procedure that aims to relieve pain, restore vertebral height, and correct kyphosis. During this procedure, an inflatable bone tamp is inserted into the collapsed vertebral body. Once inflated, the balloon elevates the end plates and thereby restores the height of the vertebral body. The balloon is deflated and removed, and the space is filled with bone cement. Creating a space in the vertebral body enables the application of more viscous cement and at a much lower pressure than is needed for vertebroplasty. This may result in less cement leakage and fewer complications. Balloons typically are inserted bilaterally, into each fractured vertebral body. Kyphoplasty usually is done under general anesthesia in about 1.5 hours. Patients typically are observed for only a few hours after the surgery, but some may require an overnight hospital stay.
Health Canada has licensed KyphX Xpander Inflatable Bone Tamp (Kyphon Inc., Sunnyvale, CA), for kyphoplasty in patients with VCFs. KyphX is the only commercially available device for percutaneous kyphoplasty. The KyphX kit uses a series of bone filler device tubes. Each bone filler device must be loaded manually with cement. The cement is injected into the cavity by pressing an inner stylet.
In the United States, the Food and Drug Administration cleared the KyphX Inflatable Bone Tamp for marketing in July 1998. CE (Conformité European) marketing was obtained in February 2000 for the reduction of fracture and/or creation of a void in cancellous bone.
Review Strategy
The aim of this literature review was to evaluate the safety and effectiveness of balloon kyphoplasty in the treatment of painful VCFs.
INAHTA, Cochrane CCTR (formerly Cochrane Controlled Trials Register), and DSR were searched for health technology assessment reports. In addition, MEDLINE, EMBASE, and MEDLINE In-Process & Other Non-Indexed Citations were searched from January 1, 2000 to September 21, 2004. The search was limited to English-language articles and human studies.
The positive end points selected for this assessment were as follows:
Reduction in pain scores
Reduction in vertebral height loss
Reduction in kyphotic (Cobb) angle
Improvement in quality of life scores
The search did not yield any health technology assessments on balloon kyphoplasty. The search yielded 152 citations, including those for review articles. No randomized controlled trials (RCTs) on balloon kyphoplasty were identified. All of the published studies were either prospective cohort studies or retrospective studies with no controls. Eleven studies (all case series) met the inclusion criteria. There was also a comparative study published in German that had been translated into English.
Summary of Findings
The results of the 1 comparative study (level 3a evidence) that was included in this review showed that, compared with conservative medical care, balloon kyphoplasty significantly improved patient outcomes.
Patients who had balloon kyphoplasty reported a significant reduction in pain that was maintained throughout follow-up (6 months), whereas pain scores did not change in the control group. Patients in the balloon kyphoplasty group did not need pain medication after 3 days. In the control group, about one-half of the patients needed more pain medication in the first 4 weeks after the procedure. After 6 weeks, 82% of the patients in the control group were still taking pain medication regularly.
Adjacent fractures were more frequent in the control group than in the balloon kyphoplasty group.
The case series reported on several important clinical outcomes.
Pain: Four studies on osteoporosis patients and 1 study on patients with multiple myeloma/primary cancers used the Visual Analogue Scale (VAS) to measure pain before and after balloon kyphoplasty. All of these studies reported that patients had significantly less pain after the procedure. This was maintained during follow-up. Two other studies on patients with osteoporosis also used the VAS to measure pain and found a significant improvement in pain scores; however, they did not provide follow-up data.
Vertebral body height: All 5 studies that assessed vertebral body height in patients with osteoporosis reported a significant improvement in vertebral body height after balloon kyphoplasty. One study had 1-year follow-up data for 26 patients. Vertebral body height was significantly better at 6 months and 1 year for both the anterior and midline measurements.
Two studies reported that vertebral body height was restored significantly after balloon kyphoplasty for patients with multiple myeloma or metastatic disease. In another study, the researchers reported complete height restoration in 9% of patients, a mean 56% height restoration in 60% of patients, and no appreciable height restoration in 31% of the patients who received balloon kyphoplasty.
Kyphosis correction: Four studies that assessed Cobb angle before and after balloon kyphoplasty in patients with osteoporosis found a significant reduction in degree of kyphosis after the procedure. In these studies, the differences between preoperative and postoperative Cobb angles were 3.4°, 7°, 8.8°, and 9.9°.
Only 1 study investigated kyphosis correction in patients with multiple myeloma or metastatic disease. The authors reported a significant improvement (5.2°) in local kyphosis.
Quality of life: Four studies used the Short Form 36 (SF-36) Health Survey Questionnaire to measure the quality of life in patients with osteoporosis after they had balloon kyphoplasty. A significant improvement in most of the domains of the SF-36 (bodily pain, social functioning, vitality, physical functioning, mental health, and role functioning) was observed in 2 studies. One study found that general health declined, although not significantly, and another found that role emotional declined.
Both studies that used the Oswestry Disability Index found that patients had a better quality of life after balloon kyphoplasty. In one study, this improvement was statistically significant. In another study, researchers found that quality of life after kyphoplasty improved significantly, as measured with the Roland-Morris Disability Questionnaire. Yet another study used a quality of life questionnaire and found that 62% of the patients that had balloon kyphoplasty had returned to normal activities, whereas 2 patients had reduced mobility.
To measure quality of life in patients with multiple myeloma or metastatic disease, one group of researchers used the SF-36 and found significantly better scores on bodily pain, physical functioning, vitality, and social functioning after kyphoplasty. However, the scores for general health, mental health, role physical, and role emotional had not improved. A study that used the Oswestry Disability Index reported that patients’ scores were better postoperatively and at 3 months follow-up.
These were the main findings on complications in patients with osteoporosis:
The bone cement leaked in 37 (6%) of 620 treated fractures.
There were no reports of neurological deficits.
There were no reports of pulmonary embolism due to cement leakage.
There were 6 cases of cardiovascular events in 362 patients:
3 (0.8%) patients had myocardial infarction.
3 (0.8%) patients had cardiac arrhythmias.
There was 1 (0.27%) case of pulmonary embolism due to deep venous thrombosis.
There were 20 (8.4%) cases of new fractures in 238 patients.
For patients with multiple myeloma or metastatic disease, these were the main findings:
The bone cement leaked in 12 (9.6%) of 125 procedures.
There were no reports of neurological deficits.
Economic Analysis
Balloon kyphoplasty requires anesthesia. Standard vertebroplasty requires sedation and an analgesic. Based on these considerations, the professional fees (Cdn) for each procedure is shown in Table 1.
Professional Fees for Standard Vertebroplasty and Balloon Kyphoplasty
Balloon kyphoplasty has a sizable device cost add-on of $3,578 (the device cost per case) that standard vertebroplasty does not have. Therefore, the up-front cost (i.e., physician’s fees and device costs) is $187 for standard vertebroplasty and $3,812 for balloon kyphoplasty. (All costs are in Canadian currency.)
There are also “downstream costs” of the procedures, based on the different adverse outcomes associated with each. This includes the risk of developing new fractures (21% for vertebroplasty vs. 8.4% for balloon kyphoplasty), neurological complications (3.9% for vertebroplasty vs. 0% for balloon kyphoplasty), pulmonary embolism (0.1% for vertebroplasty vs. 0% for balloon kyphoplasty), and cement leakage (26.5% for vertebroplasty vs. 6.0% for balloon kyphoplasty). Accounting for these risks, and the base costs to treat each of these complications, the expected downstream costs are estimated at less than $500 per case. Therefore, the expected total direct medical cost per patient is about $700 for standard vertebroplasty and $4,300 for balloon kyphoplasty.
Kyphon, the manufacturer of the inflatable bone tamps has stated that the predicted Canadian incidence of osteoporosis in 2005 is about 29,000. The predicted incidence of cancer-related vertebral fractures in 2005 is 6,731. Based on Ontario having about 38% of the Canadian population, the incidence in the province is likely to be about 11,000 for osteoporosis and 2,500 for cancer-related vertebral fractures. This means there could be as many as 13,500 procedures per year in Ontario; however, this is highly unlikely because most of the cancer-related fractures likely would be treated with medication. Given a $3,600 incremental direct medical cost associated with balloon kyphoplasty, the budget impact of adopting this technology could be as high as $48.6 million per year; however, based on data from the Provider Services Branch, about 120 standard vertebroplasties are done in Ontario annually. Given these current utilization patterns, the budget impact is likely to be in the range of $430,000 per year. This is because of the sizable device cost add-on of $3,578 (per case) for balloon kyphoplasty that standard vertebroplasty does not have.
Policy Considerations
Other treatments for osteoporotic VCFs are medical management and open surgery. In cases without neurological involvement, the medical treatment of osteoporotic VCFs comprises bed rest, orthotic management, and pain medication. However, these treatments are not free of side effects. Bed rest over time can result in more bone and muscle loss, and can speed the deterioration of the underlying condition. Medication can lead to altered mood or mental status. Surgery in these patients has been limited because of its inherent risks and invasiveness, and the poor quality of osteoporotic bones. However, it may be indicated in patients with neurological deficits.
Neither of these vertebral augmentation procedures eliminates the need for aggressive treatment of osteoporosis. Osteoporotic VCFs are often under-diagnosed and under-treated. A survey of physicians in Ontario (1) who treated elderly patients living in long-term care homes found that although these physicians were aware of the rates of osteoporosis in these patients, 45% did not routinely assess them for osteoporosis, and 26% did not routinely treat them for osteoporosis.
Management of the underlying condition that weakens the vertebral bodies should be part of the treatment plan. All patients with osteoporosis should be in a medical therapy program to treat the underlying condition, and the referring health care provider should monitor the clinical progress of the patient.
The main complication associated with vertebroplasty and balloon kyphoplasty is cement leakage (extravertebral or vascular). This may result in more patient morbidity, longer hospitalizations, the need for open surgery, and the use of pain medications, all of which have related costs. Extravertebral cement leakage can cause neurological complications, like spinal cord compression, nerve root compression, and radiculopathy. In some cases, surgery is required to remove the cement and release the nerve. The rate of cement leakage is much lower after balloon kyphoplasty than after vertebroplasty. Furthermore, the neurological complications seen with vertebroplasty have not seen in the studies of balloon kyphoplasty. Rarely, cement leakage into the venous system will cause a pulmonary embolism. Finally, compared with vertebroplasty, the rate of new fractures is lower after balloon kyphoplasty.
Diffusion – International, National, Provincial
In Canada, balloon kyphoplasty has not yet been funded in any of the provinces. The first balloon kyphoplasty performed in Canada was in July 2004 in Ontario.
In the United States, the technology is considered by some states as medically reasonable and necessary for the treatment of painful vertebral body compression fractures.
There is level 4 evidence that balloon kyphoplasty to treat pain associated with VCFs due to osteoporosis is as effective as vertebroplasty at relieving pain. Furthermore, the evidence suggests that it restores the height of the affected vertebra. It also results in lower fracture rates in other vertebrae compared with vertebroplasty, and in fewer neurological complications due to cement leakage compared with vertebroplasty. Balloon kyphoplasty is a reasonable alternative to vertebroplasty, although it must be reiterated that this conclusion is based on evidence from level 4 studies.
Balloon kyphoplasty should be restricted to facilities that have sufficient volumes to develop and maintain the expertise required to maximize good quality outcomes. Therefore, consideration should be given to limiting the number of facilities in the province that can do balloon kyphoplasty.
PMCID: PMC3387743  PMID: 23074451
8.  Open reduction of proximal humerus fractures in the adolescent population 
Proximal humerus fractures in the pediatric population are a relatively uncommon injury, with the majority of injuries treated in a closed fashion due to the tremendous remodeling potential of the proximal humerus in the skeletally immature. Yet, in adolescent patients, open treatment is, at times, necessary due to unsatisfactory alignment following a closed reduction, loss of previously achieved closed reduction, and limited remodeling when close to skeletal maturity. The purpose of our study was to examine the open reduction of adolescent proximal humerus fractures.
A retrospective review of the outcomes of proximal humerus fractures in the adolescent population which were consecutively treated at our institution with open reduction was performed.
Ten children met the inclusion criteria, with a mean age of 14.3 years (±1.3) and a mean weight of 60.7 kg (±14.9) at the time of injury. There were seven Salter-Harris 2 fractures and three Salter-Harris 1 fractures. The largest mean angulation was 55.0° (±33.9) and the largest mean displacement was 87.0 % (±22.8). Intra-operatively, impediments to closed reduction within the fracture site which were found included: periosteum (90.0 %), biceps tendon (90.0 %), deltoid muscle (70.0 %), and comminuted bone (10.0 %). K-wire fixation was most commonly used (70.0 %), followed by flexible nails (20.0 %) and cannulated screws (10.0 %) for fixation. All patients achieved radiographic union at a mean of 4.0 weeks (±0.7), had non-painful full shoulder range of motion and rotator cuff strength at final follow-up (mean 7.7 ± 4.6 months), and returned to pre-injury sporting activities.
The operative treatment of proximal humerus fracture, particularly in adolescents with severe displacement/angulation having failed closed methods of treatment, is increasingly considered to be an acceptable modality of treatment. In addition to the long head of the biceps, periosteum, deltoid muscle, and bone fragments in combination can prevent fracture reduction. Surgeon preference and skill should dictate implant choice, and the risk of physeal damage utilizing these implants in this age group is low.
PMCID: PMC3364342  PMID: 23730341
Proximal humerus; Pediatric; Adolescent; Open reduction; Operative
9.  Effects of Static Flexion-relaxation on Paraspinal Reflex Behavior 
Static trunk flexion working postures and disturbed trunk muscle reflexes are related to increased risk of low-back pain. Animal studies conclude that these factors may be related; passive tissue strain in spinal ligaments causes subsequent short-term changes in reflex. Although studies have documented changes in the myoelectric onset angle of flexion-relaxation following prolonged static flexion and cyclic flexion we could find no published evidence related to the human reflex response of the trunk extensor muscles following a period of static flexion-relaxation loading.
Eighteen subjects maintained static lumbar flexion for 15 min. Paraspinal muscle reflexes were elicited both before and after the flexion-relaxation protocol using pseudorandom stochastic force disturbances while recording EMG. Reflex gain was computed from the peak value of the impulse response function relating input force perturbation to EMG response using time-domain deconvolution analyses.
Reflexes showed a trend toward increased gain after the period of flexion-relaxation (P < 0.055) and were increased with trunk extension exertion (P < 0.021). Significant gender differences in reflex gain were observed (P < 0.01).
Occupational activities requiring extended periods of trunk flexion contribute to changes in reflex behavior of the paraspinal muscles. Results suggest potential mechanisms by which flexed posture work may contribute to low-back pain. Significant gender differences indicate risk analyses should consider personal factors when considering neuromuscular behavior.
PMCID: PMC1630677  PMID: 15567532
Low-back; Reflex; Flexion-relaxation
10.  Changes of Paraspinal Muscles in Postmenopausal Osteoporotic Spinal Compression Fractures: Magnetic Resonance Imaging Study 
Journal of Bone Metabolism  2013;20(2):75-81.
To investigate the changes of cross sectional area (CSA) in paraspinal muscles upon magnetic resonance imaging (MRI) and bone mineral density (BMD) in postmenopausal osteoporotic spinal compression fractures.
We reviewed 81 postmenopausal women with osteoporosis, who had underwent MRI examination. The patients were divided into 51 patients who had osteoporotic spinal compression fractures (group I), and 30 patients who without fractures (group II). Group I were subdivided into IA and IB, based on whether they were younger (IA) of older (IB) than 70 years of age. We additionally measured body mass index and BMD. The CSA of multifidus, erector spinae, paraspinal muscles, psoas major (PT), and intervertebral (IV) discs were measured. The degree of fatty atrophy was estimated using three grades.
The BMD and T-score of group I were significantly lower than those of group II. The CSA of erector spinae, paraspinal muscles, and PT in the group I was significantly smaller than that of group II. The CSA of paraspinal muscles in group IB were significantly smaller than those of group IA. The CSA of erector spinae, mutifidus, and PT in group IB were smaller than those of group IA, but the difference was not statistically significant. Group 1 exhibited greater fat infiltration in the paraspinal muscle than group II.
Postmenopausal osteoporotic spinal compression fracture is associated with profound changes of the lumbar paraspinal muscle, reduction of CSA, increased CSA of IV disc, and increased intramuscular fat infiltration.
PMCID: PMC3910309  PMID: 24524061
Cross-sectional area; Fractures compression; Paraspinal muscles; Postmenopause
11.  Changes in Shoulder External Rotator Muscle Activity during Shoulder External Rotation in Various Arm Positions in the Sagittal Plane 
[Purpose] The aim of this study was to investigate changes in electromyographic (EMG) activity of the infraspinatus and posterior deltoid muscles during shoulder external rotation under different shoulder flexion angles. [Subjects] Thirteen participants were included in this study. [Methods] The participants performed isometric shoulder external rotation at 45°, 90°, and 135° of shoulder flexion. A surface EMG system recorded the EMG activity of the infraspinatus and posterior deltoid muscles during shoulder external rotation. The changes in the muscle activity of infraspinatus and posterior deltoid and ratio of infraspinatus to posterior deltoid muscle activity were analyzed using one-way repeated-measures analysis of variance with Bonferroni’s correction. [Results] The posterior deltoid activity was significantly decreased, while the ratio of the infraspinatus to posterior deltoid activity was significantly increased at 45° of shoulder flexion compared with 90° and 135° of shoulder flexion (p < 0.05). There were no significant differences in the EMG activity of the infraspinatus among the three conditions (p > 0.05). [Conclusion] These findings indicate that shoulder external rotation at 45° of shoulder flexion effectively reduced the contribution of the posterior deltoid activation to shoulder external rotation.
PMCID: PMC3927026  PMID: 24567693
Infraspinatus; Posterior deltoid; Shoulder external rotation
12.  Assessment of the paraspinal muscles of subjects presenting an idiopathic scoliosis: an EMG pilot study 
It is known that the back muscles of scoliotic subjects present abnormalities in their fiber type composition. Some researchers have hypothesized that abnormal fiber composition can lead to paraspinal muscle dysfunction such as poor neuromuscular efficiency and muscle fatigue. EMG parameters were used to evaluate these impairments. The purpose of the present study was to examine the clinical potential of different EMG parameters such as amplitude (RMS) and median frequency (MF) of the power spectrum in order to assess the back muscles of patients presenting idiopathic scoliosis in terms of their neuromuscular efficiency and their muscular fatigue.
L5/S1 moments during isometric efforts in extension were measured in six subjects with idiopathic scoliosis and ten healthy controls. The subjects performed three 7 s ramp contractions ranging from 0 to 100% maximum voluntary contraction (MVC) and one 30 s sustained contraction at 75% MVC. Surface EMG activity was recorded bilaterally from the paraspinal muscles at L5, L3, L1 and T10. The slope of the EMG RMS/force (neuromuscular efficiency) and MF/force (muscle composition) relationships were computed during the ramp contractions while the slope of the EMG RMS/time and MF/time relationships (muscle fatigue) were computed during the sustained contraction. Comparisons were performed between the two groups and between the left and right sides for the EMG parameters.
No significant group or side differences between the slopes of the different measures used were found at the level of the apex (around T10) of the major curve of the spine. However, a significant side difference was seen at a lower level (L3, p = 0.01) for the MF/time parameter.
The EMG parameters used in this study could not discriminate between the back muscles of scoliotic subjects and those of control subject regarding fiber type composition, neuromuscular efficiency and muscle fatigue at the level of the apex. The results of this pilot study indicate that compensatory strategies are potentially seen at lower level of the spine with these EMG parameters.
PMCID: PMC1079862  PMID: 15760468
EMG; scoliosis; neuromuscular efficiency; muscle fatigue
13.  Prevalence of fractures in women with rheumatoid arthritis and/or systemic lupus erythematosus on chronic glucocorticoid therapy 
Glucocorticoid (GC) therapy is associated with an increased risk of fractures. The main objective of this study was to determine the prevalence of undiagnosed vertebral fractures in women chronically using GC therapy for autoimmune disorders. We also determined the prevalence of non-vertebral fractures, and investigated whether factors such as quality-of-life and future fracture risk are associated with vertebral/non-vertebral fractures.
This was a multicenter cross-sectional study conducted in Spain. All women had rheumatoid arthritis (RA) and/or systemic lupus erythematosus (SLE). Radiological morphometric vertebral fractures were evaluated centrally (Genant semiquantitative method), whereas non-vertebral fractures were not assessed by radiography. Before radiography, patients were asked whether they had vertebral/non-vertebral fractures, hereafter referred to as ‘self-reported’ fractures. Assessment tools included the Disease Activity Score (DAS28), the SF-36 questionnaire, and FRAX®.
Complete data were obtained for 576 outpatients with RA and/or SLE (83.3 % had RA); mean [SD] age 59.6 [15] years. Of all patients, 6.4 % had self-reported vertebral fractures, whereas 18.9 % had morphometric vertebral fractures (RA: 7.1 % self-reported vs. 20.0 % morphometric; SLE: 3.2 % self-reported vs. 13.7 % morphometric). Non-vertebral fractures were self-reported by 9.8 % of RA and 5.3 % of SLE patients. Low physical functioning was associated with morphometric vertebral fractures (mean [SD] SF-36 score 18.8 [6.0] when present vs. 20.1 [5.9] when absent; p = 0.028) and self-reported non-vertebral fractures (16.7 [5.2] when present vs. 20.1 [5.9] when absent; p < 0.001). Mean [SD] DAS28 was higher (p = 0.013) when any self-reported fractures were present (4.0 [1.3]) than absent (3.6 [1.3]). Based on FRAX® analysis, patients with vs. without morphometric vertebral fractures had higher 10-year probabilities of major osteoporotic fractures (mean [SD] 17.9 [12.9]% vs. 9.9 [9.6]%; p < 0.001) and hip fractures (11.0 [11.7]% vs. 4.6 [8.1]%; p < 0.001).
Morphometric vertebral fractures were detected in 18.9 % of patients, i.e. 3-times more frequently than verbally reported by patients. Patients with vs. without fractures had worse quality-of-life and increased fracture risk. Accordingly, it is of utmost importance that women chronically using GCs are assessed for fractures, including morphometric vertebral fractures.
PMCID: PMC4608160  PMID: 26472426
Prevalence; Fracture; Rheumatoid arthritis; Systemic lupus erythematosus; Glucocorticoid
14.  The prevalence of vertebral fracture amongst patients presenting with non-vertebral fractures 
Osteoporosis International  2006;18(2):185-192.
Despite vertebral fracture being a significant risk factor for further fracture, vertebral fractures are often unrecognised. A study was therefore conducted to determine the proportion of patients presenting with a non-vertebral fracture who also have an unrecognised vertebral fracture.
Prospective study of patients presenting with a non-vertebral fracture in South Glasgow who underwent DXA evaluation with vertebral morphometry (MXA) from DV5/6 to LV4/5. Vertebral deformities (consistent with fracture) were identified by direct visualisation using the Genant semi-quantitative grading scale.
Data were available for 337 patients presenting with low trauma non-vertebral fracture; 261 were female. Of all patients, 10.4% were aged 50–64 years, 53.2% were aged 65–74 years and 36.2% were aged 75 years or over. According to WHO definitions, 35.0% of patients had normal lumbar spine BMD (T-score −1 or above), 37.4% were osteopenic (T-score −1.1 to −2.4) and 27.6% osteoporotic (T-score −2.5 or lower). Humerus (n=103, 31%), radius–ulna (n=90, 27%) and hand/foot (n=53, 16%) were the most common fractures. For 72% of patients (n=241) the presenting fracture was the first low trauma fracture to come to clinical attention. The overall prevalence of vertebral deformity established by MXA was 25% (n=83); 45% (n=37) of patients with vertebral deformity had deformities of more than one vertebra. Of the patients with vertebral deformity and readable scans for grading, 72.5% (58/80) had deformities of grade 2 or 3. Patients presenting with hip fracture, or spine T-score ≤−2.5, or low BMI, or with more than one prior non-vertebral fracture were all significantly more likely to have evidence of a prevalent vertebral deformity (p<0.05). However, 19.8% of patients with an osteopenic T-score had a vertebral deformity (48% of which were multiple), and 16.1% of patients with a normal T-score had a vertebral deformity (26.3% of which were multiple). Following non-vertebral fracture, some guidelines suggest that anti-resorptive therapy should be reserved for patients with DXA-proven osteoporosis. However, patients who have one or more prior vertebral fractures (prevalent at the time of their non-vertebral fracture) would also become candidates for anti-resorptive therapy—which would have not been the case had their vertebral fracture status not been known. Overall in this study, 8.9% of patients are likely to have had a change in management by virtue of their underlying vertebral deformity status. In other words, 11 patients who present with a non-vertebral fracture would need to undergo vertebral morphometry in order to identify one patient who ought to be managed differently.
Our results support the recommendation to perform vertebral morphometry in patients who are referred for DXA after experiencing a non-vertebral fracture. Treatment decisions will then better reflect any given patient’s future absolute fracture risk. The 'Number Needed to Screen' if vertebral morphometry is used in this way would be seven to identify one patient with vertebral deformity, and 14 to identify one patient with two or more vertebral deformities. Although carrying out MXA will increase radiation exposure for the patient, this increased exposure is significantly less than would be obtained if X-rays of the dorso-lumbar spine were obtained.
PMCID: PMC1766477  PMID: 17109062
Low trauma fracture; Number needed to screen; Osteoporosis; Vertebral fracture; Vertebral morphometry
15.  Investigation of Fatigability during Repetitive Robot-Mediated Arm Training in People with Multiple Sclerosis 
PLoS ONE  2015;10(7):e0133729.
People with multiple sclerosis (MS) are encouraged to engage in exercise programs but an increased experience of fatigue may impede sustained participation in training sessions. A high number of movements is, however, needed for obtaining optimal improvements after rehabilitation.
This cross-sectional study investigated whether people with MS show abnormal fatigability during a robot-mediated upper limb movement trial. Sixteen people with MS and sixteen healthy controls performed five times three minutes of repetitive shoulder anteflexion movements. Movement performance, maximal strength, subjective upper limb fatigue and surface electromyography (median frequency and root mean square of the amplitude of the electromyography (EMG) signal of the anterior deltoid) were recorded during or in-between these exercises. After fifteen minutes of rest, one extra movement bout was performed to investigate how rest influences performance.
A fifteen minutes upper limb movement protocol increased the perceived upper limb fatigue and induced muscle fatigue, given a decline in maximal anteflexion strength and changes of both the amplitude and the median frequency of EMG the anterior deltoid. In contrast, performance during the 3 minutes of anteflexion movements did not decline. There was no relation between changes in subjective fatigue and the changes in the amplitude and the median frequency of the anterior deltoid muscle, however, there was a correlation between the changes in subjective fatigue and changes in strength in people with MS. People with MS with upper limb weakness report more fatigue due to the repetitive movements, than people with MS with normal upper limb strength, who are comparable to healthy controls. The weak group could, however, keep up performance during the 15 minutes of repetitive movements.
Discussion and Conclusion
Albeit a protocol of repetitive shoulder anteflexion movements did not elicit a performance decline, fatigue feelings clearly increased in both healthy controls and people with MS, with the largest increase in people with MS with upper limb weakness. Objective fatigability was present in both groups with a decline in the muscle strength and increase of muscle fatigue, shown by changes in the EMG parameters. However, although weak people with multiple sclerosis experienced more fatigue, the objective signs of fatigability were less obvious in weak people with MS, perhaps because this subgroup has central limiting factors, which influence performance from the start of the movements.
PMCID: PMC4516328  PMID: 26213990
16.  Control strategies to re-establish glenohumeral stability after shoulder injury 
Muscles are important “sensors of the joint instability”. The aim of this study was to identify the neuro-motor control strategies adopted by patients with anterior shoulder instability during overhead shoulder elevation in two planes.
The onset, time of peak activation, and peak magnitude of seven shoulder muscles (posterior deltoid, bilateral upper trapezius, biceps brachii, infraspinatus, supraspinatus and teres major) were identified using electromyography as 19 pre-operative patients with anterior shoulder instability (mean 27.95 years, SD = 7.796) and 25 age-matched asymptomatic control subjects (mean 23.07 years, SD = 2.952) elevated their arm above 90 degrees in the sagittal and coronal planes.
Temporal characteristics of time of muscle onsets were significantly different between groups expect for teres major in the coronal plane (t = 1.1220, p = 0.2646) Patients recruited the rotator cuff muscles earlier and delayed the onset of ipsilateral upper trapezius compared with subjects (p<0.001) that control subjects. Furthermore, significant alliances existed between the onsets of infraspinatus and supraspinatus (sagittal: r = 0.720; coronal: r = 0.756 at p<0.001) and ipsilateral upper trapezius and infraspinatus (sagittal: r = -0.760, coronal: r = -0.818 at p<0.001). The peak activation of all seven muscles occurred in the mid-range of elevation among patients with anterior shoulder instability whereas subjects spread peak activation of all 7 muscles throughout range. Peak magnitude of patients’ infraspinatus muscle was six times higher (sagittal: t = -8.6428, coronal: t = -54.1578 at p<0.001) but magnitude of their supraspinatus was lower (sagittal: t = 36.2507, coronal: t = 35.9350 at p<0.001) that subjects.
Patients with anterior shoulder instability adopted a “stability before mobility” neuro-motor control strategy to initiate elevation and a “stability at all cost” strategy to ensure concavity compression in the mid-to-150 degrees of elevation in both sagittal and coronal planes.
PMCID: PMC3898258  PMID: 24314049
Electromyography; Anterior shoulder instability; Elevation; Neuro-motor control
17.  Posturo-kinetic organisation during the early phase of voluntary upper limb movement. 1. Normal subjects. 
The nature and organisation of anticipatory postural adjustments (APA) associated with the early phase of a voluntary upper limb movement were studied. Upper limb elevations, performed at maximal velocity, were studied according to three conditions: bilateral flexions (BF) and unilateral flexions without and with an additional inertia (respectively OUF and IUF). Activities of the anterior part of the deltoid (DA) and of main muscles of the lower limbs, pelvis, trunk and scapular girdle were recorded by surface electromyography. Miniature-accelerometers enabled the recording of the tangential acceleration of the arm at wrist level (Aw) and the antero-posterior accelerations of various body links. Systematic investigations allow a precise description of the segmental phenomena which precede the onset of the voluntary movement. Before the activation of the anterior deltoid, a sequence of EMG modifications occurred in muscles of lower limbs, pelvis and trunk. The onset of Aw was preceded by anticipatory local accelerations of all the body links. Anticipatory EMG activities and local accelerations were organised according to patterns which were specific to the forthcoming voluntary movement. By comparing anticipatory EMG activities with anticipatory local accelerations, the nature of anticipatory postural movements can be determined. They appear to counteract the disturbing effects of the forthcoming voluntary movement. Because of their reproducibility and specificity, the anticipatory postural movements can be considered as preprogrammed. Postural adjustments and voluntary movement appear to be parts of the same motor program. Anticipatory postural movements should result from muscular functional synergies selected from a pre-evaluation of the perturbative aspects of the forthcoming movement.
PMCID: PMC1033201  PMID: 3204405
18.  An Electromyographic Evaluation of Subdividing Active-Assistive Shoulder Elevation Exercises 
Sports Health  2010;2(5):424-432.
Active-assistive range of motion exercises to gain shoulder elevation have been subdivided into gravity-minimized and upright-assisted exercises, yet no study has evaluated differences in muscular demands.
Compared with gravity-minimized exercises, upright-assisted exercises will generate larger electromyographic (EMG) activity. Compared with all active-assistive exercises, upright active forward elevation will generate more EMG activity.
Study design:
Controlled laboratory study.
Fifteen healthy individuals participated in this study. The supraspinatus, infraspinatus, and anterior deltoid were evaluated. The independent variables were 11 exercises performed in random order. The dependent variable was the maximum EMG amplitude of each muscle that was normalized to a maximal voluntary isometric contraction (MVIC).
Each muscle demonstrated significant differences between exercises (P < .001), with upright active forward elevation producing the greatest EMG for all muscles (95% confidence interval [CI], 12% to 50% MVIC). The orders of exercise varied by muscle, but the 5 gravity-minimized exercises always generated the lowest EMG activity. The upright-assisted exercises (95% CI, 23% to 42% MVIC) for the anterior deltoid generated more EMG activity than did the gravity-minimized exercises (95% CI, 9% to 21% MVIC) (P < .05). The infraspinatus and supraspinatus demonstrated increasing trends in EMG activity from gravity minimized to upright assisted (P > .05).
The results suggest a clear distinction between gravity-minimized exercises and upright-assisted exercises for the anterior deltoid but not for the supraspinatus and infraspinatus. Between the 2 types of assisted exercises, the results also suggest a clear distinction in terms of active elevation of the arm for the supraspinatus and anterior deltoid but not for the infraspinatus.
Clinical Relevance:
Muscle activation levels increase as support is removed, but subdivision of active-assistive range of motion to protect the supraspinatus and infraspinatus may not be necessary.
PMCID: PMC3445058  PMID: 23015971
physical therapy; rehabilitation; rotator cuff; therapeutic exercise
19.  Surface electromyography-verified muscular damage associated with the open dorsal approach to the lumbar spine 
European Spine Journal  2001;10(5):414-420.
The dorsal approach is increasingly preferred in the surgical treatment of vertebral fractures. However, the access and the implant's position cause muscle loss, which can lead to instability and a reduced capacity for rehabilitation. Morphological factors (bones, intervertebral discs) are typically blamed for chronic pain syndromes in the literature, while less importance is attached to functional factors (muscles). The objective of this study was therefore to investigate the isolated influence of dorsal spinal instrumentation on the back muscles by means of electromyography (EMG). A total of 32 patients with conditions after dorsal spondylodesis following the fracture of a vertebral body and 32 subjects with healthy backs were enrolled in this study. The EMG signal was recorded in three different muscle groups during isometric extension exercise. The evaluation was performed by comparing the mean rectified amplitudes of the three muscle groups in the patients and controls. The patients had significantly lower amplitudes in the multifidus muscle (MF) and significantly higher amplitudes in the iliocostal muscle (IL). Patients with severe pain were found to have lower electric muscle potentials in all investigated muscle groups than patients with mild pain. The muscle damage which was established in the multifidus muscle is compensated by increased activity in the iliocostal muscle. On the basis of anatomical considerations, the damage pattern can be identified as having been caused by surgery. It is extremely unlikely that trauma is the cause.
PMCID: PMC3611527  PMID: 11718196
Lumbar Spine Surgery Muscle Surface EMG Vertebral fracture
20.  Motor Outputs From the Primate Reticular Formation to Shoulder Muscles as Revealed by Stimulus-Triggered Averaging 
Journal of neurophysiology  2004;92(1):83-95.
The motor output of the medial pontomedullary reticular formation (mPMRF) was investigated using stimulus-triggered averaging (StimulusTA) of EMG responses from proximal arm and shoulder muscles in awake, behaving monkeys (M. fascicularis). Muscles studied on the side ipsilateral (i) to stimulation were biceps (iBic), triceps (iTri), anterior deltoid (iADlt), posterior deltoid (iPDlt), and latissimus dorsi (iLat). The upper and middle trapezius were studied on the ipsilateral and con-tralateral (c) side (iUTr, cUTr, iMTr, cMTr). Of 133 sites tested, 97 (73%) produced a poststimulus effect (PStE) in one or more muscles; on average, 38% of the sampled muscles responded per effective site. For responses that were observed in the arm and shoulder, poststimulus facilitation (PStF) was prevalent for the flexors, iBic (8 responses, 100% PStF) and iADlt (13 responses, 77% PStF), and poststimulus suppression (PStS) was prevalent for the extensors, iTri (22 responses, 96% PStS) and iLat (16 responses, 81% PStS). For trapezius muscles, PStS of upper trapezius (iUTr, 49 responses, 73% PStS) and PStF of middle trapezius (iMTr, 22 responses, 64% PStF) were prevalent ipsilaterally, and PStS of middle trapezius (cMTr, 6 responses, 67% PStS) and PStF of upper trapezius (cUTr, 46 responses, 83% PStS) were prevalent contralaterally. Onset latencies were significantly earlier for PStF (7.0 ± 2.2 ms) than for PStS (8.6 ± 2.0 ms). At several sites, extremely strong PStF was evoked in iUTr, even though PStS was most common for this muscle. The anatomical antagonists iBic/iTri were affected reciprocally when both responded. The bilateral muscle pair iUTr/cUTr demonstrated various combinations of effects, but cUTr PStF with iUTr PStS was prevalent. Overall, the results are consistent with data from the cat and show that outputs from the mPMRF can facilitate or suppress activity in muscles involved in reaching; responses that would contribute to flexion of the ipsilateral arm were prevalent.
PMCID: PMC2740726  PMID: 15014106
21.  Effect of Selective Muscle Training Using Visual EMG Biofeedback on Infraspinatus and Posterior Deltoid 
Journal of Human Kinetics  2014;44:83-90.
We investigated the effects of visual electromyography (EMG) biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The visual EMG biofeedback applied the pre-established threshold to prevent excessive posterior deltoid muscle contraction. A paired t-test was used to determine the significance of the measurements between without vs. with visual EMG biofeedback. Posterior deltoid activity significantly decreased while infraspinatus activity and the infraspinatus/posterior activity ratio significantly increased during side-lying shoulder external rotation exercise with visual EMG biofeedback. This suggests that using visual EMG biofeedback during shoulder external rotation exercise is a clinically effective training method for reducing posterior deltoid activity and increasing infraspinatus activity.
PMCID: PMC4327383  PMID: 25713668
EMG biofeedback; Infraspinatus; Posterior deltoid; Shoulder external rotation
22.  Restoration of Neuromuscular Control During The Pitch After Operative Treatment Of Slap Tears 
Orthopaedic Journal of Sports Medicine  2014;2(2 Suppl):2325967114S00034.
Superior labral anterior-posterior (SLAP) tears are a common cause of shoulder pain and dysfunction in overhead throwers. Treatment outcomes remain unpredictable with a large percentage of atheletes unable to return to sport. Persistent pain from the LHB (long head biceps) has been postulated as etiology of failure following repair. Previous authors have hypothesized that maximal stress is placed upon the biceps anchor during the cocking phase and that SLAP tears likely occur during this phase. We hypothesized that operative treatment of SLAP tears with repair or tenodesis would result in persistent alterations in neuromuscular control of the biceps during the overhand pitch post-operatively.
We evaluated the activity of the biceps muscle in the overhand pitching motion and correlate this activity with throwing phase in healthy collegiate and semi-professional pitchers, collegiate pitchers status-post SLAP repair, and collegiate pitchers status-post biceps tenodesis. Patients were at least one year post-operative and had returned to pitching with a painless shoulder. Subjects pitched from a regulation-sized mound while surface electrodes collected electromyographic (sEMG) signals at 1500 Hz from the long- and short-heads of the biceps (LHBM and SHBM respectively), the deltoid, the infraspinatus, and the latissimus dorsi. Motion analysis data was captured at 120 Hz with a 14-camera three-dimensional markerless motion analysis system. At least five pitches were performed by each subject. sEMG data was then normalized to maximal manual muscle testing and then divided into previously described pitching phases (wind-up, stride, cocking, acceleration, deceleration, follow-through).
Eighteen pitchers participated: 7 normals, 6 status-post SLAP repair, and 5 status-post tenodesis. While no significant differences were observed in mean LHBM, SHBM, deltoid, infraspinatus, or latissimus activity between normals, pitchers status-post SLAP repair, and pitchers status-post tenodesis during each phase, loss of the normal activation contours was seen for both pitchers status-post SLAP repair and those status-post tenodesis, suggesting continued reflex inhibition. As confirmation, significantly less overactivity (>100% activity) was seen in post-operative deltoids than normal deltoids (p=0.025).
Simultaneous EMG and motion analysis of pitchers status-post operative treatment of SLAP tears suggests that while tenodesis and repair may restore physiologic muscular activation amplitude, persistent changes in activation contours persist for both tenodesis and repair. Both treatments may have biomechanical and neuromuscular consequences, even in pitchers with a full painless return to play. Further study is needed to determine potential differences between patients with persistent pain following surgery, as well as differing treatment modalities (tenotomy, tenodesis, repair).
PMCID: PMC4597500
23.  A Biomechanical Assessment of Ergometer Task Specificity in Elite Flatwater Kayakers 
The current study compared EMG, stroke force and 2D kinematics during on-ergometer and on-water kayaking. Male elite flatwater kayakers (n = 10) performed matched exercise protocols consisting of 3 min bouts at heart and stroke rates equivalent to 85% of VO2peak (assessed by prior graded incremental test). EMG data were recorded from Anterior Deltoid (AD), Triceps Brachii (TB), Latissimus Dorsi (LD) and Vastus Lateralis (VL) via wireless telemetry. Video data recorded at 50 Hz with audio triggers pre- and post-exercise facilitated synchronisation of EMG and kinematic variables. Force data were recorded via strain gauge arrays on paddle and ergometer shafts. EMG data were root mean squared (20ms window), temporally and amplitude normalised, and averaged over 10 consecutive cycles. In addition, overall muscle activity was quantified via iEMG and discrete stroke force and kinematic variables computed. Significantly greater TB and LD mean iEMG activity were recorded on-water (239 ± 15 vs. 179 ± 10 μV. s, p < 0.01 and 158 ± 12 vs. 137 ± 14 μV.s, p < 0.05, respectively), while significantly greater AD activity was recorded on-ergometer (494 ± 66 vs. 340 ± 35 μV.s, p < 0.01). Time to vertical shaft position occurred significantly earlier on-ergometer (p < 0.05). Analysis of stroke force data and EMG revealed that increased AD activity was concurrent with increased external forces applied to the paddle shaft at discrete phases of the on-ergometer stroke cycle. These external forces were associated with the ergometer loading mechanism and were not observed on- water. The current results contradict a previous published hypothesis on shoulder muscle recruitment during on-water kayaking.
Key pointsWhen exercising at fixed heart and stroke rates, biomechanical differences exist between onergometer and on-water kayaking.Ergometer kayaking results in significantly greater Anterior Deltoid activity but significantly lower Triceps Brachii and Latissimus Dorsi activity, compared with on-water kayaking.The altered muscle recruitment patterns observed on-ergometer are most likely a result of additional forces associated with the ergometer loading mechanism, acting upon the paddle shaft.
PMCID: PMC3737857  PMID: 24149118
Kayaking; ergometry; electromyography; stroke force; stroke kinematics
24.  Risk of Injurious Fall and Hip Fracture up to 26 y before the Diagnosis of Parkinson Disease: Nested Case–Control Studies in a Nationwide Cohort 
PLoS Medicine  2016;13(2):e1001954.
Low muscle strength has been found in late adolescence in individuals diagnosed with Parkinson disease (PD) 30 y later. This study investigated whether this lower muscle strength also may translate into increased risks of falling and fracture before the diagnosis of PD.
Methods and Findings
Among all Swedish citizens aged ≥50 y in 2005, two nested case–control cohorts were compiled. In cohort I, individuals diagnosed with PD during 1988–2012 (n = 24,412) were matched with up to ten controls (n = 243,363), and the risk of fall-related injuries before diagnosis of PD was evaluated. In cohort II, individuals with an injurious fall in need of emergency care during 1988–2012 (n = 622,333) were matched with one control (n = 622,333), and the risk of PD after the injurious fall was evaluated. In cohort I, 18.0% of cases and 11.5% of controls had at least one injurious fall (p < 0.001) prior to PD diagnosis in the case. Assessed by conditional logistic regression analysis adjusted for comorbid diagnoses and education level, PD was associated with increased risks of injurious fall up to 10 y before diagnosis (odds ratio [OR] 1.19, 95% CI 1.08–1.31; 7 to <10 y before diagnosis) and hip fracture ≥15 y before diagnosis (OR 1.36, 95% CI 1.10–1.69; 15–26 y before diagnosis). In cohort II, 0.7% of individuals with an injurious fall and 0.5% of controls were diagnosed with PD during follow-up (p < 0.001). The risk of PD was increased for up to 10 y after an injurious fall (OR 1.18, 95% CI 1.02–1.37; 7 to <10 y after diagnosis). An important limitation is that the diagnoses were obtained from registers and could not be clinically confirmed for the study.
The increased risks of falling and hip fracture prior to the diagnosis of PD may suggest the presence of clinically relevant neurodegenerative impairment many years before the diagnosis of this disease.
In two nested case-control studies using data from a nationwide cohort, Peter Nordström and colleagues assess the risk of injurious fall and hip fracture up to 26 years before the diagnosis of Parkinson's disease.
Editors' Summary
Parkinson disease (PD) is a common, progressive neurological disease. The disease is caused by the gradual loss of the nerve cells that usually produce dopamine, a neurotransmitter that regulates the body’s movements (motor functions). The symptoms of PD, which develop slowly, include tremor (involuntary trembling of the hands, legs, arm, jaw, and face), slow movement, impaired balance and coordination, and rigidity (muscle stiffness). As these symptoms worsen, affected individuals may have trouble walking, speaking, and swallowing, and they may fall frequently, fracturing bones. No drugs are available to halt the loss of dopamine-producing nerve cells, but medications that replace or mimic the lost dopamine can reduce the severity of these motor symptoms. PD does not directly kill people, and many people with PD have a normal or near-normal life expectancy. However, PD puts a great strain on the body, which makes affected individuals vulnerable to life-threatening infection such as pneumonia.
Why Was This Study Done?
The motor symptoms of PD do not usually develop until people are around 60 years old. However, nonspecific “prodromal” signs (for example, changes in smell perception) can occur many years earlier. Indeed, a recent study reported low muscle strength in late adolescence in patients diagnosed with PD decades later. Could reduced muscular strength be a marker of neuromuscular dysfunction (problems with the nerves that control movement), and could this dysfunction translate into an increased risk of falls and fractures years before PD diagnosis? Here, researchers investigate these questions by undertaking a nested case—control study in a nationwide cohort. A nested case—control study identifies all the individuals in a group (here, everyone living in Sweden who was 50 years old or older at the end of 2005) who have a specific condition (here, PD), identifies several matched individuals (people who are similar to the cases in terms of age, gender, and certain other characteristics) in the same cohort who do not have the condition, and asks whether the cases and controls differ in terms of a specific characteristic (here, falls and fall-related injuries up to 26 years before the diagnosis of PD).
What Did the Researchers Do and Find?
The researchers identified 24,412 Swedish citizens who were diagnosed with PD between 1988 and 2012 by examining the Swedish National Patient Register and matched each case with up to ten controls to form a nested case—control cohort. During an average study period of 20 years prior to a PD diagnosis, 18.0% of cases and 11.5% of controls had at least one fall that caused an injury requiring emergency care. After adjusting for other factors that might affect an individual’s risk of a fall, PD was associated with an increased risk of injurious falls up to ten years before diagnosis (an odds ratio [OR] of 1.19; an OR represents the chance that an outcome will occur given a particular exposure compared to the chance of the outcome occurring in the absence of that exposure) and with an increased risk of hip fracture more than 15 years before diagnosis (OR 1.36; hip fractures are particularly common among people with PD). The strength of these associations was increased closer to PD diagnosis. Finally, in a second nested case—control cohort in which individuals with a record of injurious falls were matched with individuals with no history of falls, the risk of PD was higher among individuals with an injurious fall than among those without during the first ten years after the first recorded fall.
What Do These Findings Mean?
The use of diagnoses obtained from registers that could not be clinically confirmed may limit the accuracy of these findings. Moreover, these findings cannot prove that there is a shared causal link between injurious falls and PD (although the time-dependent changes in the strength of the associations and the results from the second nested case—control cohort strongly suggest a direct link between injurious falls and subsequent PD). However, the finding that the risk of injurious falls—particularly the risk of falls resulting in hip fracture—is increased decades prior to the diagnosis of PD suggests that clinically relevant but subtle neurodegenerative impairment could be present many years before the clinical onset of PD. These findings, which identify potential markers of PD more than a decade before diagnosis, need to be confirmed in other settings but provide new insights into the earliest, hitherto unrecognized, stages of PD.
Additional Information
This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at
The US National Institute of Neurological Disorders and Stroke provides detailed information about Parkinson disease (in English and Spanish), including links to US organizations that help people with Parkinson disease
The UK National Health Service Choices website provide information on all aspects of Parkinson disease (including personal stories)
The UK not-for-profit organization Parkinson’s UK and the US not-for-profit organization National Parkinson Foundation also provide detailed information about Parkinson disease and personal stories
The UK not-for-profit organization provides stories about all aspects of living with Parkinson disease
MedlinePlus has links to further resources about Parkinson disease (in English and Spanish)
Wikipedia has a page on nested case—control studies (note that Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
PMCID: PMC4737490  PMID: 26836965
25.  Neuromuscular Fatigue During 200 M Breaststroke 
The aims of this study were: i) to analyze activation patterns of four upper limb muscles (duration of the active and non-active phase) in each lap of 200m breaststroke, ii) quantify neuromuscular fatigue, with kinematics and physiologic assessment. Surface electromyogram was collected for the biceps brachii, deltoid anterior, pectoralis major and triceps brachii of nine male swimmers performing a maximal 200m breaststroke trial. Swimming speed, SL, SR, SI decreased from the 1st to the 3rd lap. SR increased on the 4th lap (35.91 ± 2.99 stroke·min-1). Peak blood lactate was 13.02 ± 1.72 mmol·l-1 three minutes after the maximal trial. The EMG average rectified value (ARV) increased at the end of the race for all selected muscles, but the deltoid anterior and pectoralis major in the 1st lap and for biceps brachii, deltoid anterior and triceps brachii in the 4th lap. The mean frequency of the power spectral density (MNF) decreased at the 4th lap for all muscles. These findings suggest the occurrence of fatigue at the beginning of the 2nd lap in the 200m breaststroke trial, characterized by changes in kinematic parameters and selective changes in upper limb muscle action. There was a trend towards a non-linear fatigue state.
Key PointsFatigue in the upper limbs occurs in different way as it described by 100m swimming events.Neuromuscular fatigue was estimated by analyzing the physiological changes (high blood lactate concentrations), biomechanical changes in the swimming stroke characteristics (decreased in swimming velocity), and by the changes in the EMG amplitude and frequency parameters at the end of the swimming bout.The amplitude signal of EMG provided by the ARV demonstrated an increase at the end with the respect to the beginning for all muscles under study, excepted for the muscle deltoid anterior.The mean frequency (MNF) in our study decrease at the end of the swimming in the 4th lap relative to the 1st lap for all muscles under observation, along the 200m breaststroke.
PMCID: PMC3918558  PMID: 24570625
Swimming; Kinematics; EMG; Mean frequency

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