High-intensity Zone Research Articles

MRI Findings of Disc Degeneration are More Prevalent in Adults with Low Back Pain than in Asymptomatic Controls: A Systematic Review and Meta-Analysis.

Imaging features of spine degeneration are common in symptomatic and asymptomatic individuals. We compared the prevalence of MR imaging features of lumbar spine degeneration in adults 50 years of age and younger with and without self-reported low back pain. We performed a meta-analysis of studies reporting the prevalence of degenerative lumbar spine MR imaging findings in asymptomatic and symptomatic adults 50 years of age or younger. Symptomatic individuals had axial low back pain with or without radicular symptoms. Two reviewers evaluated each article for the following outcomes: disc bulge, disc degeneration, disc extrusion, disc protrusion, annular fissures, Modic 1 changes, any Modic changes, central canal stenosis, spondylolisthesis, and spondylolysis. The meta-analysis was performed by using a random-effects model. An initial search yielded 280 unique studies. Fourteen (5.0%) met the inclusion criteria (3097 individuals; 1193, 38.6%, asymptomatic; 1904, 61.4%, symptomatic). Imaging findings with a higher prevalence in symptomatic individuals 50 years of age or younger included disc bulge (OR, 7.54; 95% CI, 1.28-44.56; P = .03), spondylolysis (OR, 5.06; 95% CI, 1.65-15.53; P < .01), disc extrusion (OR, 4.38; 95% CI, 1.98-9.68; P < .01), Modic 1 changes (OR, 4.01; 95% CI, 1.10-14.55; P = .04), disc protrusion (OR, 2.65; 95% CI, 1.52-4.62; P < .01), and disc degeneration (OR, 2.24; 95% CI, 1.21-4.15, P = .01). Imaging findings not associated with low back pain included any Modic change (OR, 1.62; 95% CI, 0.48-5.41, P = .43), central canal stenosis (OR, 20.58; 95% CI, 0.05-798.77; P = .32), high-intensity zone (OR = 2.10; 95% CI, 0.73-6.02; P = .17), annular fissures (OR = 1.79; 95% CI, 0.97-3.31; P = .06), and spondylolisthesis (OR = 1.59; 95% CI, 0.78-3.24; P = .20). Meta-analysis demonstrates that MR imaging evidence of disc bulge, degeneration, extrusion, protrusion, Modic 1 changes, and spondylolysis are more prevalent in adults 50 years of age or younger with back pain compared with asymptomatic individuals.

Risk factors for a recurrence of low back pain

Background contextThe clinical importance of lumbar pathology identified on magnetic resonance imaging (MRI) remains unclear. It is plausible that pathology seen on MRI is a risk factor for a recurrence of low back pain (LBP); however, to our knowledge, this has not been investigated by previous studies. PurposeThe aim was to investigate whether lumbar pathology, identifiable on MRI, increases the risk of a recurrence of LBP. Study designThis was a prospective inception cohort study with 1-year follow-up. Patient sampleSeventy-six people who had recovered from an episode of LBP within the previous 3 months were included. Outcome measuresThe primary outcome was time to recurrence of LBP, which was determined by contacting participants at 2-month intervals for 12 months. MethodsAll participants underwent a baseline assessment including MRI scan and completion of a questionnaire, which assessed a range of potential risk factors for recurrence. Magnetic resonance imaging scans were reported for the presence of a range of MRI findings. The primary analysis investigated the predictive value of two clinical features (age and number of previous episodes) and six MRI findings (disc degeneration, high intensity zone, Modic changes, disc herniation, facet joint arthrosis, and spondylolisthesis) in a multivariate Cox regression model. We decided a priori that dichotomous predictors with hazard ratios (HRs) of greater than 1.5 or less than 0.67 would be considered potentially clinically important and justify further investigation. ResultsOf the eight predictors entered into the primary multivariate model, three (disc degeneration, high intensity zone, and number of previous episodes) met our a priori threshold for potential importance. Participants with disc degeneration score greater than or equal to 3 (Pfirrmann scale) had a HR of 1.89 (95% confidence interval [CI] 0.42–8.53) compared with those without. Patients with high intensity zone had an HR of 1.84 (95% CI 0.94–3.59) compared with those without. For every additional previous episode, participants had an HR of 1.04 (95% CI 1.02–1.07). ConclusionsWe identified promising risk factors for a recurrence of LBP, which should be further investigated in larger trials. The findings suggest that pathology seen on MRI plays a potentially important role in recurrence of LBP.

The prevalence of degenerative or incidental findings in the lumbar spine of pediatric patients: a study using magnetic resonance imaging as a screening tool.

Several studies using magnetic resonance imaging (MRI) to evaluate the lumbar spine in adults have shown a large prevalence of degenerative changes in asymptomatic subjects; however, studies in pediatric patients are scarce. Those studies have suggested a lower rate of degenerative findings in adolescents than in adults, but the actual prevalence of MRI findings in the pediatric population has not yet been determined. We aimed to determine the prevalence of degenerative changes in the lumbar spine of pediatric patients using abdominal and pelvic MRI as the screening tool. We studied 103 patients (mean age 6.6 years) who were evaluated with abdominal and pelvic MRI for indications that were not spine related. The entire lumbo-sacral spine was evaluated to detect the presence of disc degeneration (DD), disc displacement, anular rupture with high-intensity zone (HIZ) and Modic changes. In our population, 10.7 % [4.9-16.5] had at least one disc classified as Pfirrmann 2, and no patients presented discs classified as Pfirrmann 3, 4 or 5; patients exhibiting discs classified as Pfirrmann 2 were significantly older than patients who had only Pfirrmann 1 discs. The prevalence of disc bulging was 1 % [0-2.9]. No patients presented disc herniation (including protrusion or extrusions); additionally, no patients exhibited HIZ or Modic changes. Incidental findings related to DD are very uncommon at this early age, in contrast to findings described in adults or later in adolescence.

Heart rate-based training intensity and its impact on injury incidence among elite-level professional soccer players.

Elite-level professional soccer players are suggested to have increased physical, technical, tactical, and psychological capabilities when compared with their subelite counterparts. Ensuring these players remain at the elite level generally involves training many different bodily systems to a high intensity or level within a short duration. This study aimed to examine whether an increase in training volume at high-intensity levels was related to injury incidence, or increased the odds of sustaining an injury. Training intensity was monitored through time spent in high-intensity (T-HI) and very high-intensity (T-VHI) zones of 85-<90% and ≥90% of maximal heart rate (HRmax), and all injuries were recorded over 2 consecutive seasons. Twenty-three, elite professional male soccer players (mean ± SD age, 25.6 ± 4.6 years; stature, 181.8 ± 6.8 cm; and body mass, 79.3 ± 8.1 kg) were studied throughout the 2-years span of the investigation. The results showed a mean total injury incidence of 18.8 (95% confidence interval [CI], 14.7-22.9) injuries per 1,000 hours of exposure. Significant correlations were found between training volume at T-HI and injury incidence (r = 0.57, p = 0.005). Further analysis revealed how players achieving more time in the T-VHI zone during training increased the odds of sustaining a match injury (odds ratio = 1.87; 95% CI, 1.12-3.12, p = 0.02) but did not increase the odds of sustaining a training injury. Reducing the number of competitive match injuries among elite-level professional players may be possible if greater focus is placed on the training intensity and volume over a period of time ensuring the potential reduction of fatigue or overuse injuries. In addition, it is important to understand the optimal training load at which adaptation occurs without raising the risk of injury.

Clinical and Surgical Correlation with MRI Findings in Herniated Lumbar Disc: Towards Clinical and Surgical Application of the Current Classification Oriented Understanding of the Morphology of the Herniated Lumbar Disc

Background Data: Herniated lumbar discs requiring surgery are evaluated preoperatively by magnetic resonance imaging. This helps the surgeon to appreciate the size, direction and morphology of the herniated disc material and aids planningthe surgical procedure. The currently available MRI based classifications and terminology do correlate clinical, surgical and prognostic information. Purpose: Our study aims to find clinical and/or surgical correlation between the morphology of different disc herniations based on MRI findings with correlation to the clinical and surgical findings. Study Design: Retrospective analysis of 117 patients who had lumbar microdiscectomy for single level herniated lumbar discs.Patients and Methods: Preoperative MRI was thoroughly examined and the level, laterality, the presence of High Intensity Zone (HIZ) on T2 MRI and Modic changes were recorded. Furthermore, all disc levels were analyzed using theMichigan University Grading System (MSU), the Pfirmann grading for degree of disc degeneration. We subdivided the fragment according to its base diameter on sagittal MRI into: uniform, protruded, extruded and sequestrated. Noted was the fragment direction. The signal intensity of the herniated material in T2 weighted images was reported. We then correlated using statistical analysis each of the MSU Grade, Pfirmann Grade, fragment morphology, fragment signal and fragment migration with the preoperative duration of symptoms, self-reported Visual Analogue Score for leg pain (VAS), neurological deficit, sphincters dysfunction and straight leg raising, blood loss, incision length, bony work, the amount of disc material removed and the shape of the fragment, length of hospital stay, early postoperative sciatica, unintended durotomy, recurrent sciatica, redo surgery within the first year. Results: The mean age was 39.3 years, 70% were males, 47% were L4-5, and 47.9% were L5-S1. Unilateral left herniation was reported in 52.1%, right in 31.6%, central in 12%, and bilateral in 4.3%. Patients were classified as IIAB in 36, IIB in 28, III AB in 24, HIZ in 7. Caudal migration was reported in 28.2%, straight posterior in 64.1%, and cranial migration in 7.7%. The fragments were dark gray on T2WI in 66 (56.4%) patients. Fragment base was uniform in 53 (45.3%) patients. Most of our surgically treated disc prolapses were Pfirmann, Grade 3 and 4. There was no statistical significance between any of the preoperative clinical or the surgical or the postoperative parameters and Pfrimann grade, MSU grade, fragment base, fragment signal, sagittal extent(P>0.05). Except for a statistically significance between the disc size according to MSU classification and the severity of the preoperative leg pain (VAS) (P=0.01) and the preoperative SLR (P=0.005). There was also a statistically significant correlation between the operative time and the fragment base (P=0.006) Conclusion: Not all disc herniations are similar. On our first attempt to clinically and surgically correlate some of these classifications, we found few clinical and surgical correlations with herniated fragment morphology. A more surgically oriented classification scheme would be useful and applicable for surgeons to anticipate the degree of difficulty of surgery and the plan required for adequate nerve root decompression. (2015ESJ079)

Analysis and comparison of intensity in specific soccer training sessions

This study compared the exercise intensity of four specific soccer training sessions (friendly and training match, tactical and technical workouts). Ten professional soccer players (24.2 ± 3.7 years, 177.9 ± 7.3 cm, 63.2 ± 4.6 mLO2•kg-1•min-l) were recruited. A treadmill progressive interval test was performed to determine the players' VO2max, maximal heart rate (HRmax), HR-VO2 curve, and the heart rate corresponding to blood lactate concentrations of 2 and 4 mmol/L. The heart rate during the training sessions was used to estimate the exercise intensity and to classify them into intensity zones (low-intensity: &lt;2 mmol/L; moderate-intensity: between 2 and 4 mmol/L; high-intensity: &gt;4 mmol/L). Exercise intensities were different among training sessions (friendly match: 86.0 ± 5.1% HRmax; training match: 81.2 ± 4.1% HRmax; tactical workout: 70.4 ± 5.3% HRmax; technical workout: 62.1 ± 3.6% HRmax). The friendly match presented the highest percentage of time performed in the high-intensity zone.

Reliability and variability in the interpretation of lumbar high intensity zone.

The aim of this study was to evaluate the reliability of high intensity zone (HIZ) and to assess discrepancy in the interpretation, as well as investigate the effects of parameters of HIZ on interobserver variation. Four spine surgeons made independent observations on lumbar magnetic resonance imaging (MRI) from 207 consecutive patients from 3 institutions. The κ statistic was used to characterize inter- and intraobserver reliability for visual assessments of HIZ. The corresponding MRI was provided to 2 additional spine surgeons for quantitative measurements. The parameters of HIZ, including signal intensity (SI) and area ratio (HIZ%), were used to assess the interobserver variation of HIZ. The overall interobserver agreement for visual assessments was substantial (κ=0.62 at L4-5 and 0.61 at L5-S1), and intraobserver agreement was excellent (κ=0.84 at L4-5 and 0.86 at L5-S1). Of 93 observed HIZ, 17 instances (18.3%) were agreed upon by all visual observers. The SI with full agreement was significantly brighter than all the others (p<0.01). The HIZ% with 2 agreements was significantly smaller than those with 4 agreements (p=0.04) and 3 agreements (p=0.03). Although fewer observers with consensus were associated with smaller HIZ%, the difference was not significant (p>0.05). The reliability in the interpretation of HIZ was sufficient for spine surgeons with differing levels of experience. This study highlighted that signal intensity was the primary cause of variability in visual observation.

Patient selection and efficacy of intradiscal electrothermal therapy with respect to dallas discogram score

Intervertebral disc degeneration can cause severe low back pain. Intradiscal electrothermal therapy (IDET) is a minimally invasive treatment option for patients with symptomatic internal disc disruption unresponsive to conservative medical care. We aimed to evaluate 12-month pain and functional outcomes and predictors of clinical success in patients with discogenic back pain treated with IDET with respect to the Dallas Discogram Scale (DDS). This was a retrospective analysis of patients undergoing IDET for low back pain from 2009 through 2014 at Baskent University, Department of Neurosurgery. A total number of 120 consecutive patients data were collected retrospectively. The degree of disc degeneration was graded using the DDS during discography, and the presence of a high intensity zone (HIZ) on magnetic resonance (MR) imaging was noted. The primary outcome measure was assessment of back pain severity based on the Visual Analogue Scale (VAS); function was assessed by the Oswestry Disability Index (ODI). Follow-up examinations for ODI and VAS scores were assessed at 1, 6, and 12 months post-treatment. Outcomes were discussed with respect to morphological changes in intervertebral discs on discogram. There was an average 57.39% and 47.16% improvement in VAS and ODI scores, respectively, between pretreatment and 12 months follow-up (p < 0.0001 for both comparisons). Predictors of 12-month clinical success was depended on DDS (p < 0.0001), a HIZ on MR imaging (p < 0.0001). Durable clinical improvements can be realized after IDET in select surgical candidates with mild disc degeneration and HIZ, discography, and low-grade DDS, with more effective treatment results.

Effect of Posterior Dynamic Instrumentation on High-Intensity Zone in Lumbar Degenerative Disc Disease.

To investigate high-intensity zone (HIZ) changes after lumbar posterior dynamic instrumentation. Our study included 53 patients: 27 patients in group 1, 26 patients in group 2. All patients had one or two levels of degenerative disc disease with an HIZ confirmed by magnetic resonance imaging (MRI). Group 1 underwent one- or two-level dynamic lumbar posterior instrumentation. Group 2 was treated conservatively with an exercise program. Patients were evaluated using MRI, a numerical visual analog pain scale (VAS), and the Oswestry Disability Index (ODI) at baseline, at 1 year after surgery, and at final follow-up evaluation. The mean duration of follow-up was 49.3 months in group 1 and 47.19 months in group 2. The baseline VAS and ODI scores were similar for both groups. The mean VAS score of group 1 was significantly improved at 1 year after surgery and at final follow-up. The mean ODI value was lower in group 1 than in group 2 at 1 year and at final follow-up. Pfirrmann grades in group 1 significantly differed at 1 year and at final follow-up but did not change in group 2. The number of HIZs significantly decreased in from baseline to 1 year and from baseline to final follow-up in group 1 but did not differ in group 2. Dynamic lumbar stabilization systems are promising. Observations such as Pfirrmann grade improvements and disappearance of HIZs are concordant with improvements in VAS and ODI scores demonstrate that dynamic stabilization systems may provide an environment for regeneration.

The Factors Associated With the Successful Outcomes of Percutaneous Disc Decompression in Patients With Lumbar Herniated Nucleus Pulposus.

ObjectiveTo determine clinical and radiological factors that predict the successful outcome of percutaneous disc decompression (PDD) in patients with lumbar herniated nucleus pulposus (HNP).MethodsWe retrospectively reviewed the clinical and radiological features of patients who underwent lumbar PDD from April 2009 to March 2013. Sixty-nine patients with lumbar HNP were studied. Clinical outcome was assessed by the visual analogue scale (VAS) and the Oswestry Disability Index (ODI). Multivariate logistic regression analysis was performed to assess relationship among clinical and radiological factors and the successful outcome of the PDD.ResultsThe VAS and the ODI decreased significantly at 1 year follow-up (p<0.01). One year after PDD, the reduction of the VAS (ΔVAS) was significantly greater in the patients with pain for <6 months (p=0.03) and subarticular HNP (p=0.015). The reduction of the ODI (ΔODI) was significantly greater in the patients with high intensity zone (p=0.04). Multivariate logistic regression analysis revealed the following 5 factors that were associated with the successful outcome after PDD: pain duration for <6 months (odds ratio [OR]=14.036; p=0.006), positive straight leg raising test (OR=8.425, p=0.014), the extruded HNP (OR=0.106, p=0.04), the sequestrated HNP (OR=0.037, p=0.026), and the subarticular HNP (OR=10.876, p=0.012).ConclusionPDD provided significant improvement of pain and disability of patients. The results of the analysis indicated that the duration of pain <6 months, positive straight leg raising test, the subarticular HNP, and the protruded HNP were predicting factors associated with the successful response of PDD in patients with lumbar HNP.

Intra-Annular Granulation Tissue Syndrome: Clinico-Histological Study of High Intensity Zones and the Role of Percutaneous Endoscopic Lumbar Annuloplasty as Therapy with Two Years Follow-up

Intra-Annular Granulation Tissue Syndrome: Clinico-Histological Study of High Intensity Zones and the Role of Percutaneous Endoscopic Lumbar Annuloplasty as Therapy with Two Years Follow-up

Regression between MR findings of lumbar elements and chronic low back pain

Objective To investigate the relationship between the MR findings of lumbar elements and chronic low back pain(CLBP). Methods The patients underwent lumbar MRI examinations and sent for a questionnaires of low back pain (LBP). Among them, 139 patients whose questionnaires illustrated with CLBP were enrolled. The enrolled patients included 68 patients with nerve roots compression and 71 patients without. Meanwhile, 198 hospital staffs underwent lumbar MRI examinations and were sentfor a LBP questionnaire.Among them, 62 patients without LBP and nerve roots compression were enrolled. Categorical regression was used to analyze the relationship between MR findings and CLBP. The MR findings included nerve roots compression, average disk degeneration scores(ADD), high-intensity zones (HIZ), Schmorlnodes, Modic Ⅰ change, average facet joints degeneration scores(AZZ), facet joint effusion, high T2 signal in interspinous ligament and subcutaneousparaspinal muscles edema. The regression model was used to analyze the MR imaging and CLBP. Results The regression model was statistically significant (F=9.478,P<0.01). All predictors yielded an adjusted value was 0.446. Among all predictors, nerve roots compression, ADD, AZZ, subcutaneous or paraspinal muscles edema were statistically associated with the VAS degree (P<0.05). The sum of the importance of the four predictors above was 0.983. The quantification of predicted VAS degree increased as ADD level increased. The quantification of predicted VAS degree increased to the top at the 2 AZZ level and then decreased. Nerve roots compression and Subcutaneous or paraspinal muscles edema yielded higher quantification of predicted VAS degree level. Conclusion ADD, AZZ, subcutaneousparaspinal muscles edema were probably associated with CLBP degree after adjusting for nerve roots compression. Key words: Low back pain; Magnetic resonance imaging; Visual analogue scale

A novel classification system of lumbar disc degeneration

The Pfirrmann and modified Pfirrmann grading systems are currently used to classify lumbar disc degeneration. These systems, however, do not incorporate variables that have been associated with lumbar disc degeneration, including Modic changes, a high intensity zone, and a significant reduction in disc height. A system that incorporates these variables that is easy to apply may be useful for research and clinical purposes. A grading system was developed that incorporates disc structure and brightness, presence or absence of Modic changes, presence or absence of a high intensity zone, and reduction in disc height (disc height less than 5mm). MRI of 300 lumbar discs in 60 patients were analyzed twice by two neurosurgeons. Intra and inter-observer reliabilities were assessed by calculating Cohen’s κ values. There were 156 grade zero (“normal”), 50 grade one, 57 grade two, 26 grade three, 10 grade four, and one grade five (“worst”) discs. Inter-observer reliability was substantial (κ=0.66 to 0.77) for disc brightness/structure, Modic changes, and disc height. Inter-observer reliability was moderate (κ=0.41) for high intensity zone. Intra-observer reliability was moderate to excellent (κ=0.53 to 0.94) in all categories. Agreement on the total grade between reviewers occurred 71% of the time and a difference of one grade occurred in an additional 25% of cases. Lumbar disc degeneration can be graded reliably by this novel system. The advantage of this system is that it incorporates disc brightness/structure, Modic changes, high intensity zone, and a rigid definition of loss of disc height. This system might be useful in research studies evaluating disc degeneration. Further studies are required to demonstrate possible clinical utility in predicting outcomes after spinal treatments such as fusion.

A quantitative study of intervertebral disc morphologic changes following plasma-mediated percutaneous discectomy.

To quantitatively evaluate interval magnetic resonance imaging (MRI) changes in disc morphology following plasma-mediated percutaneous discectomy. A retrospective comparison of pretreatment and posttreatment MRIs at a single university spine clinic. From a group of 60 consecutively treated patients, 15 met the study inclusion and exclusion criteria. All had either failed treatment or had other clinical reasons for a posttreatment MRI. Two independent physicians electronically measured disc protrusion size and disc height at the treatment discs and adjacent discs on pre- and posttreatment MRI scans. Additionally, images were compared for gross anatomic changes including disc degeneration by Pfirrman classification, new disc herniations, high intensity zone (HIZ), vertebral endplate changes, post-contrast enhancement, and changes in segmental alignment. Pearson r correlation was used to determine interobserver reliability between the two physicians' MRI measurements. Paired t-tests were calculated for comparisons of pre- and posttreatment MRI measurements, and an ANOVA was performed for comparison of pre- to posttreatment changes in disc height measurements at treatment levels relative to adjacent levels. Correlation was high for measurement of disc height change (r = 0.89; P < 0.0001) and good for anteroposterior protrusion size change (r = 0.51; P = 0.0512). Disc height at treated discs demonstrated a small but statistically significant mean interval reduction of 0.48 mm (P = 0.0018). This remained significant when compared with the adjacent control discs (P < 0.0001). Pretreatment mean disc protrusion size (4.74 mm; range 3.75-6.55 mm) did not differ significantly (P = 0.1145) from posttreatment protrusion size (4.42 mm; range 2.55-7.95 mm). Gross anatomic changes at treatment levels included reduced disc protrusion size (N = 6), enlarged protrusion (N = 3), resolution of HIZ (N = 3), and improvement in endplate signal changes (N = 1). Also, 11/15 posttreatment MRIs included post-contrast images that showed epidural fibrosis (N = 1), rim enhancement (N = 2), and enhancement of the posterior annulus (N = 4). Based on MRI examinations, subtle anatomic changes may occur following plasma-mediated percutaneous discectomy. Further study is required to determine the clinical relevance of these changes.

Incidental Findings on Magnetic Resonance Imaging of the Spine in the Asymptomatic Pediatric Population: A Systematic Review

Study Design Systematic review. Clinical Question What is the prevalence of incidental magnetic resonance imaging (MRI) findings of the spine in asymptomatic pediatric patients? Methods Electronic databases and reference lists of key articles were searched up to December 15, 2013, to identify studies reporting the incidence or prevalence of incidental findings on MRI in asymptomatic pediatric patients. Athletes or children with a known history of trauma, infection, or congenital abnormalities were excluded. Results Seven publications, one prospective cohort, and six cross-sectional studies met the inclusion criteria. The most commonly reported findings on MRI were disc-related and included degenerative disc disease (seven studies, prevalence 19.6%), disc herniation/protrusion (four studies, 2.9%), disc height/narrowed disc space (two studies, 33.7%), and endplate changes (two studies, 5.3%). Other disc-related findings, reported by one study each, included bulging disc, abnormal nucleus shape, annular tear, high intensity zone, and nerve root compression, with prevalences ranging from 4.5 to 51.6%. Spondylolisthesis and spondylolysis were reported by one study each with a prevalence of 2.3 and 0%, respectively. Other findings reported included tumors and infections (one study, 0% for both) and Scheuermann-type changes (one study, 7.7%). Conclusions The prevalence of positive MRI findings in the asymptomatic pediatric population is higher than previously assumed, particularly in regard to disc morphology, highlighting the importance of correlating the history and physical examination to the MRI findings to avoid misdiagnosis or over-treatment in the pediatric population.

Effect of number of touches and exercise duration on the kinematic profile and heart rate response during small-sided games in soccer.

This study aimed to examine the effect of exercise duration and the number of touches allowed during possession on time-motion characteristics and the physiological responses of soccer players in 6 vs. 6 small-sided games (SSGs) lasting 12 minutes. The analysis divided each game into two 6-min periods and we compared two formats: free play (SSGFP) vs. a maximum of two touches per individual possession (SSG2T). Participants were 12 semi-professional players (age: 22.7±4.3 years; body height: 177.5±4.9 cm; body mass: 74.9±6.3 kg) and the following variables were measured by means of heart rate monitors and GPS devices: mean heart rate (HRmean), time spent in each exercise intensity zone, total distance covered, total distance covered in different speed zones, number of accelerations at different intensities, maximum speed reached, player load, and the work-to-rest ratio. The results showed that in SSGFP there was a decrease in the intensity of physical parameters during the second 6-min period (6–12 min), whereas this decrease was not observed when a maximum of two touches per individual possession was allowed. During the second period (6–12 min) of SSG2T there was an increase in HRmean and in the time spent in high exercise intensity zones, but these differences were not observed in SSGFP. The value of these findings for soccer coaches is that they illustrate how different technical, tactical or conditioning objectives could be addressed by altering the length and format of the SSG used in training.

Surgical results and prognostic factors of anterior cervical corpectomy and fusion for ossification of the posterior longitudinal ligament.

BackgroundMechanism of ossification of the posterior longitudinal ligament (OPLL) has not been elucidated clearly. Surgical decompression is usually necessary for the patients with neurological symptoms. Anterior decompression and resection of OPLL seems to be a radical surgical option, because the spinal cord is compressed from the anterior direction.MethodsAmong 229 patients who underwent ACF for OPLL between January 2001 and December 2007 in our hospital, a total of 133 patients responded to the invitation and made return visits, with a follow-up rate of 58.1%. For these patients, clinical data were collected from medical and operative records. Neurological status were evaluated by using the Japanese Orthopedic Association (JOA) scoring system. Radiological evaluations including C2-7 lordotic angle, sagittal vertical axis (SVA), occupying rate of OPLL, double-layer sign and high-intensity zone were obtained from all the patients. Complications and causes of revision surgery were also investigated. Correlations between the long-term surgical outcome and various prognostic factors were statistically analyzed.FindingsEighty-four males and forty-nine females completed the follow-up, with a mean age at operation of 56.8 years. The overall average JOA score significantly increased, with a mean recovery rate of 64.1%±14.2%. The mean C2-7 lordotic angle and SVA were also significantly improved, and fusion rate was satisfactory. The incidence of complications was consistent to the previous reports and most of them were controllable by suitable treatments. Multiple regression analysis showed that number of corpectmies and preoperative JOA score were important predictors of surgical outcome.ConclusionsACF is a reliable and effective method for treating OPLL patients in terms of neurological recovery, maintenance of radiological parameters, fusion rate and complications. Number of corpectomies and preoperative JOA score are important predictors for the clinical outcome when this procedure is used.

Finite Element Analysis of Anti-Seismic Performance of Flange Connection in Circular-Pipe Tower Structures

For tower structures located in high-intensity seismic zone, despite the importance of anti-seismic performance in flange connection, far less attention has been given to it. Based on finite element analysis results carried by ANSYS software, under pressure and moment, influence of stiffener height and axial compression stress ratio of steel pipe on the anti-seismic performance of flange connection was studied. The main results shows that lower axial compression stress ratio of steel pipe or higher stiffener height would improve the anti-seismic performance of flange connection. And closer flange connection from the end restraint would lead to better anti-seismic performance.

Magnetic resonance imaging study of disc low back pain

To study the diagnostic value of disc low back pain (DLBP) with lumbar disc high-intensity zone on magnetic resonance imaging (MRI) . The 21 patients of pare examination with MRI and CT discography (CTD) must have chronic low back pain without radicular pain and with no disc herniation on the CT or MRI. We have worked out the standard of CTD group and positive disc. The sensitivity, specificity and positive predictive value that the positive disc was diagnosed with MRI was used for statistical analysis in SPSS 15.0. MRI showed 28 abnormal signal discs in 21 patients, including the high-intensity zone of posterior annulus in 12 discs and later- posterior annulus in 3 discs and discs degeneration in other 13 discs. The results of pare examination with MRI and CTD to 28 abnormal signal discs and 5 normal signal discs was (1)MRI showed the high-intensity zone of poster annulus in 12 discs and later- poster annulus in 2 discs and discs degeneration in 5 discs, while CTD showed 19 discs for group 2 with all positive discs. The shape of high-intensity zone showed on MRI was showed no difference with the shape of contrast agent collected under periphery disc on CTD. (2) MRI showed another high-intensity zone of later- poster annulus in 3 discs, while CTD showed one disc for group 5 with positive. (3) MRI showed the discs degeneration, while CTD showed 7 discs for group 3 with negative discs. (4) MRI showed 1 disc degeneration and 5 normal discs, while CTD showed 6 discs for group 1 with negative discs. (5)The sensitivity of diagnosis positive discs was 75%, the specificity and positive predictive value was respectively 100% with MRI. The high-intensity zone of poster/later- poster annulus on MRI was typical sign of disc disruption and the important clinical role for diagnosing disc low back pain.

Discogenic lower back pain: Current concepts

AbstractThe literature reports that 39% of chronic lower back pain may be attributed to intervertebral disc derangement. However, definitive diagnosis of discogenic lower back pain (DLBP) remains challenging. Clinical examination may be normal and the correlative utility of magnetic resonance imaging findings such as the high intensity zone is controversial. Researchers have identified a complex interplay of degenerative, immunohistological, and biomechanical overload factors as causative. Due to difficulties in diagnosis through physical examination and imaging alone, provocative discography is still the gold standard for surgical planning, by measuring intradiscal pressure, finding extradiscal dye extravasation, and by reproducing concordant pain against controls. This remains so, despite the known sequelae of latent acceleration of disc degeneration following the procedure. Lumbar interbody fusion (LIF), in its various forms, is the traditional surgical management for intractable pain from DLBP. Howeve...