The concept of minimally invasive lumbar disc surgery comprises reduced muscle injury. The aim of this study was to evaluate creatine phosphokinase (CPK) in serum and the cross-sectional area (CSA) of the multifidus muscle on magnetic resonance imaging as indicators of muscle injury. We present the results of a double-blind randomized trial on patients with lumbar disc herniation, in which tubular discectomy and conventional microdiscectomy were compared. In 216 patients, CPK was measured before surgery and at day 1 after surgery. In 140 patients, the CSA of the multifidus muscle was measured at the affected disc level before surgery and at 1 year after surgery. The ratios (i.e. post surgery/pre surgery) of CPK and CSA were used as outcome measures. The multifidus atrophy was classified into three grades ranging from 0 (normal) to 3 (severe atrophy), and the difference between post and pre surgery was used as an outcome. Patients’ low-back pain scores on the visual analogue scale (VAS) were documented before surgery and at various moments during follow-up. Tubular discectomy compared with conventional microdiscectomy resulted in a nonsignificant difference in CPK ratio, although the CSA ratio was significantly lower in tubular discectomy. At 1 year, there was no difference in atrophy grade between both groups nor in the percentage of patients showing an increased atrophy grade (14% tubular vs. 18% conventional). The postoperative low-back pain scores on the VAS improved in both groups, although the 1-year between-group mean difference of improvement was 3.5 mm (95% CI; 1.4–5.7 mm) in favour of conventional microdiscectomy. In conclusion, tubular discectomy compared with conventional microdiscectomy did not result in reduced muscle injury. Postoperative evaluation of CPK and the multifidus muscle showed similar results in both groups, although patients who underwent tubular discectomy reported more low-back pain during the first year after surgery.
Creatine phosphokinase; Muscle injury; Atrophy; Microdiscectomy; Herniated disc; Low-back pain
The aim of this study was to assess the cross-sectional area (CSA) of both paraspinal and psoas muscles in patients with unilateral back pain using MRI and to correlate it with outcome measures.
40 patients, all with informed consent, with a minimum of 3 months of unilateral back pain with or without sciatica and one-level disc disease on MRI of the lumbosacral spine were included. Patients were evaluated with self-report measures regarding pain (visual analogue score) and disability (Oswestry disability index). The CSA of multifidus, erector spinae, quadratus lumborum and psoas was measured at the disc level of pathology and the two adjacent disc levels, bilaterally. Comparison of CSAs of muscles between the affected vs symptomless side was carried out with Student's t-test and correlations were conducted with Spearman's test.
The maximum relative muscle atrophy (% decrease in CSA on symptomatic side) independent of the level was 13.1% for multifidus, 21.8% for erector spinae, 24.8% for quadratus lumborum and 17.1% for psoas. There was significant difference (p<0.05) between sides (symptomatic and asymptomatic) in CSA of multifidus, erector spinae, quadratus lumborum and psoas. However, no statistically significant correlation was found between the duration of symptoms (average 15.5 months), patient's pain (average VAS 5.3) or disability (average ODI 25.2) and the relative muscle atrophy.
In patients with long-standing unilateral back pain due to monosegmental degenerative disc disease, selective multifidus, erector spinae, quadratus lumborum and psoas atrophy develops on the symptomatic side. Radiologists and clinicians should evaluate spinal muscle atrophy of patients with persistent unilateral back pain.
To investigate the prognostic value of cross-sectional areas (CSA) of paraspinal (multifidus and erector spinae) and psoas muscles on magnetic resonance imaging (MRI) in chronicity of low back pain.
Thirty-eight subjects who visited our hospital for acute low back pain were enrolled. Review of their medical records and telephone interviews were done. Subjects were divided into two groups; chronic back pain group (CBP) and a group showing improvement within 6 months after onset of pain (IBP). The CSA of paraspinal and psoas muscles were obtained at the level of the lower margin of L3 and L5 vertebrae using MRI.
CSA of erector spinae muscle and the proportion of the area to lumbar muscles (paraspinal and psoas muscles) at L5 level in the CBP group were significantly smaller than that of the IBP group (p<0.05). The mean value of CSA of multifidus muscle at L5 level in the CBP group was smaller than that of the IBP group, but was not statistically significant (p>0.05). CSA of psoas muscle at L5 level and all values measured at L3 level were not significantly different between the groups (p>0.05).
CSA of erector spinae muscle at the lower lumbar level and the proportion of the area to the lumbar muscles at the L5 level can be considered to be prognostic factors of chronicity of low back pain.
Low back pain; Magnetic resonance imaging; Cross-sectional area; Muscles
Decreased activity of the lumbar stabilizer muscles has been identified in individuals with sway-back posture. Disuse can predispose these muscles to atrophy, which is characterized by a reduced cross-sectional area (CSA) and by fat infiltration. The aim of this study was to evaluate the amount of fat infiltration in the lumbar multifidus and lumbar erector spinae muscles as a sign of the muscle atrophy in individuals with sway-back posture, with and without low back pain.
Materials and methods
Forty-five sedentary individuals between 16 and 40 years old participated in this study. The sample was divided into three groups: symptomatic sway-back (SSBG) (n = 15), asymptomatic sway-back (ASBG) (n = 15), and control (CG) (n = 15). The individuals were first subjected to photographic analysis to classify their postures and were then referred for a magnetic resonance imaging (MRI) examination of the lumbar spine. The total (TCSA) and functional (FCSA) cross-sectional areas of the lumbar erector spinae together with lumbar multifidus and isolated lumbar multifidus muscles were measured from L1 to S1. The amount of fat infiltration was estimated as the difference between the TCSA and the FCSA.
Greater fat deposition was observed in the lumbar erector spinae and lumbar multifidus muscles of the individuals in the sway-back posture groups than in the control group. Pain may have contributed to the difference in the amount of fat observed in the groups with the same postural deviation. Similarly, sway-back posture may have contributed to the tissue substitution relative to the control group independently of low back pain.
The results of this study indicate that individuals with sway-back posture may be susceptible to morphological changes in their lumbar erector spinae and lumbar multifidus muscles, both due to the presence of pain and as a consequence of their habitual posture.
Multifidus; Erector spinae; Magnetic resonance imaging; Posture; Sway-back
Increasing documentation on the size and appearance of muscles in the lumbar spine of low back pain (LBP) patients is available in the literature. However, a comparative study between unoperated chronic low back pain (CLBP) patients and matched (age, gender, physical activity, height and weight) healthy controls with regard to muscle cross-sectional area (CSA) and the amount of fat deposits at different levels has never been undertaken. Moreover, since a recent focus in the physiotherapy management of patients with LBP has been the specific training of the stabilizing muscles, there is a need for quantifying and qualifying the multifidus. A comparative study between unoperated CLBP patients and matched control subjects was conducted. Twenty-three healthy volunteers and 32 patients were studied. The muscle and fat CSAs were derived from standard computed tomography (CT) images at three different levels, using computerized image analysis techniques. The muscles studied were: the total paraspinal muscle mass, the isolated multifidus and the psoas. The results showed that only the CSA of the multifidus and only at the lowest level (lower end-plate of L4) was found to be statistically smaller in LBP patients. As regards amount of fat, in none of the three studied muscles was a significant difference found between the two groups. An aetiological relationship between atrophy of the multifidus and the occurrence of LBP can not be ruled out as a possible explanation. Alternatively, atrophy may be the consequence of LBP: after the onset of pain and possible long-loop inhibition of the multifidus a combination of reflex inhibition and substitution patterns of the trunk muscles may work together and could cause a selective atrophy of the multifidus. Since this muscle is considered important for lumbar segmental stability, the phenomenon of atrophy may be a reason for the high recurrence rate of LBP.
Key words Cross-sectional area; Fat deposits; Paravertebral muscles; Lumbar multifidus; Psoas
The purpose was to investigate the changes of the psoas major muscles (PM) cross-sectional area (CSA) and fat infiltration in the PM and to investigate the association between the morphology of the PM and expression of the degenerative changes of lumbar spine in patients with low back pain (LBP).
T2-weighted scans for measurements of the CSA and analysis of fat infiltration were performed on 42 patients and 49 controls using a 1.5 Tesla MR system. For a quantitative analysis of fat tissue infiltration a 4-grade visual scale was used.
Patients had bigger CSA of the PM than controls at the levels of L3/L4 and L4/L5 intervertebral disc (P < 0.05). Patients with apparent degenerative changes of the lumbar spine had smaller CSA of the PM compared to the patients without apparent changes at the levels of L3/L4 and L4/L5 (P < 0.05). At the levels of L4/L5 and L5/S1 patients with present Modic changes in the lumbar vertebral bodies showed smaller CSA of the PM compared to the patients without Modic changes (P < 0.05). However, CSA of the PM in the patients with degenerative changes of lumbar spine and Modic changes was still bigger than the one of the controls. At all analyzed levels correlation between CSAs of the PM and fat infiltration of the lumbar paraspinal muscles was negative.
Results suggest increased activity of the PM in LBP patients but PM also remains active regardless of the presence of degenerative and Modic changes of the lumbar spine.
Psoas major muscle; Low back pain; MRI; Disc degeneration; Modic changes
We set out to determine whether a minimally invasive approach for one-level instrumented posterior lumbar interbody fusion reduced undesirable changes in the multifidus muscle, compared to a conventional open approach. We also investigated associations between muscle injury during surgery (creatinine kinase levels), clinical outcome and changes in the multifidus at follow-up. We studied 59 patients treated by one team of surgeons at a single institution (minimally invasive approach in 28 and conventional open approach in 31, voluntarily chosen by patients). More than 1 year postoperatively, all the patients were followed up with the visual analogue scale (VAS) and Oswestry disability index (ODI), and 16 patients from each group were evaluated using MRI. This enabled the cross-sectional area (CSA) of lean multifidus muscle, and the T2 signal intensity ratio of multifidus to psoas muscle, to be compared at the operative and adjacent levels. The minimally invasive group had less postoperative back pain (P < 0.001) and lower postoperative ODI scores (P = 0.001). Multifidus atrophy was less in the minimally invasive group (P < 0.001), with mean reductions in CSA of 12.2% at the operative and 8.5% at the adjacent levels, compared to 36.8% and 29.3% in the conventional open group. The increase in the multifidus:psoas T2 signal intensity ratio was similarly less marked in the minimally invasive group where values increased by 10.6% at the operative and 8.3% at the adjacent levels, compared to 34.4 and 22.7% in the conventional open group (P < 0.001). These changes in multifidus CSA and T2 signal intensity ratio were significantly correlated with postoperative creatinine kinase levels, VAS scores and ODI scores (P < 0.01). The minimally invasive approach caused less change in multifidus, less postoperative back pain and functional disability than conventional open approach. Muscle damage during surgery was significantly correlated with long-term multifidus muscle atrophy and fatty infiltration. Furthermore these degenerative changes of multifidus were also significantly correlated with long-term clinical outcome.
Minimally invasive; Lumbar spine; Multifidus muscle; Interbody fusion
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.
Cross-sectional area; Fractures compression; Paraspinal muscles; Postmenopause
To identify determinants of musculoskeletal deficits (muscle cross-sectional area [mCSA], trabecular volumetric bone mineral density [vBMD], and cortical bone strength [section modulus]) in patients with juvenile idiopathic arthritis (JIA) and to determine if cortical bone strength is appropriately adapted to muscle forces.
Peripheral quantitative computed tomography (pQCT) of the tibia was performed in 101 patients with JIA (79% female; 24 with oligoarticular JIA, 40 with polyarticular JIA, 18 with systemic JIA, and 19 with spondylarthritis [SpA]) and 830 healthy control subjects; all were ages 5–22 years. Outcomes of pQCT were expressed as sex- and race-specific Z scores. Multivariable linear regression models assessed mCSA and bone status in JIA patients compared with controls and identified factors associated with musculoskeletal deficits in JIA.
The median duration of JIA was 40 months; 29% of the JIA patients had active arthritis, and 28% had received glucocorticoid therapy during the previous year. Compared with the controls, the mCSA and section modulus Z scores were significantly lower in patients with polyarticular JIA and those with SpA. Trabecular vBMD Z scores were significantly lower in patients with polyarticular JIA, those with systemic JIA, and those with SpA. Significant predictors of musculoskeletal deficits included active arthritis in the previous 6 months (mCSA), temporomandibular joint disease (mCSA and section modulus), functional disability (mCSA and vBMD), short stature (vBMD), infliximab exposure (vBMD), and JIA duration (section modulus). The section modulus was significantly reduced relative to mCSA in patients with JIA after adjustment for age and limb length.
Marked deficits in vBMD and bone strength occur in JIA in association with severe and longstanding disease. Contrary to the findings of previous studies, bone deficits were greater than expected relative to the mCSA, which illustrates the importance of adjusting for age and bone length.
Cross-sectional studies in dialysis demonstrate muscle wasting associated with loss of function, increased morbidity and mortality. The relative drivers are poorly understood. There is a paucity of data regarding interval change in muscle in pre-dialysis and dialysis-dependant patients. This study aimed to examine muscle and fat mass change and elucidate associations with muscle wasting in advanced CKD.
134 patients were studied (60 HD, 28 PD, 46 CKD 4–5) and followed up for two years. Groups were similar in age, sex and diabetes prevalence. Soft tissue cross-sectional area (CSA) was measured annually on 3 occasions by a standardised multi-slice CT thigh. Potential determinants of muscle and fat CSA were assessed. Functional ability was assessed by sit-to-stand testing.
88 patients completed follow-up (40 HD, 16 PD, 32 CKD). There was a significant difference in percentage change in muscle CSA (MCSA) over year 1, dependant on treatment modality (χ2 = 6.46; p = 0.039). Muscle loss was most pronounced in pre-dialysis patients. Muscle loss during year 1 was partially reversed in year 2 in 39%. Incident dialysis patients significantly lost MCSA during the year which they commenced dialysis, but not the subsequent year. Baseline MCSA, change in MCSA during year 1 and dialysis modality predicted year 2 change in MCSA (adjusted R2 = 0.77, p<0.001). There was no correlation between muscle or fat CSA change and any other factors. MCSA correlated with functional testing, although MCSA change correlated poorly with change in functional ability.
These data demonstrate marked variability in MCSA over 2 years. Loss of MCSA in both pre-dialysis and established dialysis patients is reversible. Factors previously cross-sectionally shown to correlate with MCSA did not correlate with wasting progression. The higher rate of muscle loss in undialysed CKD patients, and its reversal after dialysis commencement, suggests that conventional indicators may not result in optimal timing of dialysis initiation.
Objectives—To determine the effect of different training schedules on the cross sectional area (CSA) of the lumbar multifidus muscle in patients with chronic low back pain.
Methods—Each of 59 nine patients was randomly assigned to one of three programmes: 10 weeks of stabilisation training (group 1; n = 19); 10 weeks of stabilisation training combined with dynamic resistance training (group 2; n = 20); 10 weeks of stabilisation training combined with dynamic-static resistance training (group 3; n = 20). Before and after 10 weeks of training, multifidus CSAs were measured from standard computed tomography images at three different levels (upper end plate of L3 and L4, and lower end plate of L4).
Results—The CSA of the multifidus muscle was significantly increased at all levels after training in group 3. In contrast, no significant differences were found in groups 1 and 2.
Conclusions—General stabilisation exercises and dynamic intensive lumbar resistance training have no significant effect on the CSA of the lumbar multifidus muscle in patients with chronic low back pain. The static holding component between the concentric and eccentric phase was found to be critical in inducing muscle hypertrophy during the first 10 weeks. Treatment consisting of stabilisation training combined with an intensive lumbar dynamic-static strengthening programme seems to be the most appropriate method of restoring the size of the multifidus muscle.
Key Words: back pain; multifidus muscle; stabilisation; dynamic; dynamic-static; hypertrophy
Despite recognized evidence for the importance of the multifidus muscle in stabilizing the lumbar spine, identifying subjects at risk for injury and subsequent loss of intrinsic spinal stabilization remains difficult. Previous research has failed to associate multifidus muscle size and height, weight, or body mass index (BMI). The purpose of this study was to begin to establish normative data for the multifidus muscle cross-sectional area (CSA) at the L5 level and to identify factors associated with size. Twenty-five participants (17 female), with a mean age of 32.5 (SD 11.6) years without history of LBP were considered for inclusion. Participants' height and weight were recorded and BMI calculated. Ultrasound imaging was used to obtain a CSA in cm2 of the subjects' multifidus muscles at the L5 level bilaterally; testing was done by two trained testers. Prior to testing, intra- and inter-tester reliability were determined. Percent body fat was determined using a three-site skinfold caliper measurement, also using two trained testers. Mean BMI was 24.18 and mean body fat (%) was 22.88 for all participants. As expected, age and BMI were moderately correlated. Left and right multifidus muscle CSA were highly correlated (r = 0.92, p < 0.001). The mixed model ANOVA indicated a significant main effect for gender as males exhibited larger CSA than females. Participants without history of low back pain present with symmetrical multifidus muscle CSA at the L5 level. Clear gender differences in CSA show that males tend to have larger multifidus muscles at the L5 level, indicating a need to establish gender-specific norms for clinicians examining the L5 multifidus muscle.
Lumbar Spine; Multifidus; Sonography
Main problem: Previous studies have demonstrated that sciatica patients have poorer postural control than healthy controls and that postural control remains unchanged 3 months after lumbar discectomy in sciatica patients. The aims of the current study were to investigate whether static balance control recovers in pain-free discectomy patients long-term after lumbar discectomy. Next is to determine whether static balance responses of asymptomatic and symptomatic lumbar discectomy patients differed from each other and from healthy controls. In addition, the influence of the extent of disc resection (unilateral/bilateral removal) and the side of operation on static balance control were investigated. Methods: Fifteen pain-free lumbar discectomy patients, 23 lumbar discectomy patients with residual pain and 72 controls performed unilateral stance tasks with eyes open and eyes closed on a force plate were taken up for the investigation. Three repetitions of a 10 s unilateral stance test were performed on each leg. Postural sway was determined. Patients were divided into three age groups. Results: In the eyes open condition, there was no significant difference between postural sway of pain-free lumbar discectomy patients and controls (P=0.68), whereas balance of patients with pain was significantly worse than in controls (P=0.003). In the eyes closed condition, the sway in both groups of lumbar discectomy patients was significantly worse than in controls (pain-free P=0.009/painful P<0.001). No significant differences were found in postural sway between patients with unilateral and bilateral disc resection. In unilateral stance on the leg of the operated side, centre of gravity sway was not significantly different in the eyes open condition compared to the eyes closed condition, whereas in stance on the leg of the non-operated side, postural sway was significantly lower in the eyes open condition compared to the eyes closed condition. In both conditions, postural sway in the age group of 50–65 years was significantly higher than in the age groups of 30–39 years (eyes open P=0.005; eyes closed P<0.001) and 40–49 years (eyes open P=0.002; eyes closed P=0.006). There was no significant difference between the age group of 30–39 years and the age group of 40–49 years (P=0.51). Conclusion: As for long-term following lumbar discectomy, there is no complete recovery of postural control. Patients seem to develop visual compensation mechanisms for underlying sensory–motor deficits, which are, however, sufficient in case of pain relief only. Further study is needed to determine the cause of the balance disturbances in lumbar discectomy patients.
Postural control; Unilateral stance; Lumbar discectomy; Visual compensation
To quantitatively evaluate the asymmetry of the multifidus and psoas muscles in unilateral sciatica caused by lumbar disc herniation using magnetic resonance imaging (MRI).
Seventy-six patients who underwent open microdiscectomy for unilateral L5 radiculopathy caused by disc herniation at the L4-5 level were enrolled, of which 39 patients (51.3%) had a symptom duration of 1 month or less (group A), and 37 (48.7%) had a symptom duration of 3 months or more (group B). The cross-sectional areas (CSAs) of the multifidus and psoas muscles were measured at the mid-portion of the L4-5 disc level on axial MRI, and compared between the diseased and normal sides in each group.
The mean symptom duration was 0.6±0.4 months and 5.4±2.7 months for groups A and B, respectively (p<0.001). There were no differences in the demographics between the 2 groups. There was a significant difference in the CSA of the multifidus muscle between the diseased and normal sides (p<0.01) in group B. In contrast, no significant multifidus muscle asymmetry was found in group A. The CSA of the psoas muscle was not affected by disc herniation in either group.
The CSA of the multifidus muscle was reduced by lumbar disc herniation when symptom duration was 3 months or more.
Multifidus; Psoas; Cross-sectional area; Lumbar disc herniation
The purpose of this study was to investigate the use of magnetic resonance (MR) imaging and image processing software to determine the functional cross-sectional area (FCSA) (the area of muscle isolated from fat) of the lumbar paraspinal muscles. The measurement of the morphology of the lumbar paraspinal muscles has become the focus of several recent investigations into the aetiology of low back pain. However, the reliability and validity of determining the FCSA of the lumbar paraspinal muscles using MR imaging are yet to be reported. T2 axial MR scans at the L1-S1 spinal levels of six subjects were obtained using identical MR systems and scanning parameters. Lean paraspinal muscle, vertebral body bone and intermuscular fat were manually segmented using image analysis software to assign a grey scale range to the MR signal intensity emitted by each tissue type. The resultant grey scale range for muscle was used to determine FCSA measurements for each of the paraspinal muscles, psoas, quadratus lumborum, erector spinae and lumbar multifidus on each scan slice. As various biological, instrument and measurement factors can affect MR signal intensity, a sensitivity analysis was conducted to determine the error associated in calculating FCSA for paraspinal muscle using a discrete grey scale range. Cross-sectional area and FCSA measurements were repeated three times and reliability indices for the FCSA measurements were obtained, showing excellent reliability, intra class correlation coefficient (mean=0.97, range 0.90–0.99) and %SEM (mean=2.6%, range 0.7–4.8%). In addition, the error associated with miscalculation of the grey scale range for the MR signal intensity of muscle was calculated and found to be low with an error of 20 grey scale units at the upper end of the muscle’s grey scale range resulting in a very small error in the measured muscle FCSA. The method presented in this paper has a variety of practical applications in areas such as evidence-based rehabilitation, biomechanical modelling and the determination of segmental inertial parameters.
Lumbar spine; Magnetic resonance imaging; Cross sectional area; Low back pain; Muscle morphology
To evaluate the relationship between the cross sectional area (CSA) and isokinetic strength of the back muscles in patients with chronic low back pain.
Data of twenty-eight middle-aged patients with chronic back pain were analyzed retrospectively. CSAs of both paraspinal muscles and the disc at the L4-L5 level were measured in MRI axial images and the relative CSAs (rCSA: CSA ratio of muscle and disc) were calculated. The degree of paraspinal muscle atrophy was rated qualitatively. Isokinetic strengths (peak torque, peak torque per body weight) of back flexor and extensor were measured with the isokinetic testing machine. Multiple regression analysis with backward elimination was used to evaluate relations between isokinetic strength and various factors, such as CSA or rCSA and clinical characteristics in all patients. The same analysis was repeated in the female patients.
In analysis with CSA and clinical characteristics, body mass index (BMI) and CSA were significant influencing factors in the peak torque of the back flexor muscles. CSA was a significant influencing factor in the peak torque of total back muscles. In analysis with rCSA and clinical characteristics, BMI was significant in influencing the peak torque of the back flexors. In female patients, rCSA was a significant influencing factor in the peak torque per body weight of the back flexors, and age and BMI were influencing factors in the peak torque of back flexors and total back muscles.
In middle-aged patients with chronic low back pain, CSA and rCSA were influencing factors in the strength of total back muscles and back flexors. Also, gender and BMI were influencing factors.
Low back pain; Muscle strength; Muscle strength dynamometer; Magnetic resonance imaging
Back extension exercises are often used in the rehabilitation of low back pain. However, at present it is not clear how the posterior muscles are recruited during different types of extension exercises. Therefore, the present study will evaluate the myoelectric activity of thoracic, lumbar and hip extensor muscles during different extension exercises in healthy persons. Based on these physiological observations we will make recommendations regarding the use of extensions exercises in clinical practice.
Fourteen healthy subjects performed four standardized extension exercises (dynamic trunk extension, dynamic-static trunk extension, dynamic leg extension, dynamic-static leg extension) in randomized order at an intensity of 60% of 1-RM (one repetition maximum). Surface EMG signals of Latissimus dorsi (LD), Longissimus thoracis pars thoracic (LTT) and lumborum (LTL), Iliocostalis lumborum pars thoracic (ILT) and lumborum (ILL), lumbar Multifidus (LM) and Gluteus Maximus (GM) were measured during the various exercises. Subsequently, EMG root mean square values were calculated and compared between trunk and leg extension exercises, as well as between a dynamic and dynamic-static performance using mixed model analysis. During the dynamic exercises a 2 second concentric contraction was followed by a 2 second eccentric contraction, whereas in the dynamic-static performance, a 5 second isometric interval was added in between the concentric and eccentric contraction phase.
In general, the muscles of the posterior chain were recruited on a higher level during trunk extension (mean ± SD, 56.6 ± 30.8%MVC) compared to leg extension (47.4 ± 30.3%MVC) (p ≤ 0.001). No significant differences were found in mean muscle activity between dynamic and dynamic-static performances (p = 0.053). The thoracic muscles (LTT and ILT) were recruited more during trunk extension (64.9 ± 27.1%MVC) than during leg extension (54.2 ± 22.1%MVC) (p = 0.045) without significant differences in activity between both muscles (p = 0.138). There was no significant differences in thoracic muscle usage between the dynamic or dynamic-static performance of the extension exercises (p = 0.574).
Lumbar muscle activity (LTT, ILL, LM) was higher during trunk extension (70.6 ± 22.2%MVC) compared to leg extension (61.7 ± 27.0%MVC) (p = 0.047). No differences in myoelectric activity between the lumbar muscles could be demonstrated during the extension exercises (p = 0.574). During each exercise the LD (19.2 ± 13.9%MVC) and GM (28.2 ± 14.6%MVC) were recruited significantly less than the thoracic and lumbar muscles.
The recruitment of the posterior muscle chain during different types of extension exercises was influenced by the moving body part, but not by the type of contraction. All muscle groups were activated at a higher degree during trunk extension compared to leg extension. Based on the recruitment level of the different muscles, all exercises can be used to improve the endurance capacity of thoracic muscles, however for improvement of lumbar muscle endurance leg extension exercises seem to be more appropriate. To train the endurance capacity of the LD and GM extension exercises are not appropriate.
Trunk extensor muscles; Multifidus; Posterior muscle chain; Extension exercise; Electromyography; Spine
We have conducted a unique prospective randomized study to compare the effect of FK506 and cyclosporine (CsA) as the principal immunosuppressive agents after pulmonary transplantation. Between October 1991 and March 1993, 74 lung transplants (35 single lung transplants [SLT], 39 bilateral lung transplant [BLT]) were performed on 74 recipients who were randomly assigned to receive either FK or CsA. Thirty-eight recipients (19 SLT, 19 BLT) received FK and 36 recipients (16 SLT, 20 BLT) received CsA. Recipients receiving FK or CsA were similar in age, gender, preoperative New York Heart Association functional class, and underlying disease. Acute rejection (ACR) was assessed by clinical, radiographic, and histologic criteria. ACR was treated with methylprednisolone, 1 g i.v./day, for three days or rabbit antithymocyte globulin if steroid-resistant.
During the first 30 days after transplant, one patient in the FK group died of cerebral edema, while two recipients treated with CsA died of bacterial pneumonia (1) and cardiac arrest (1) (P=NS). Although one-year survival was similar between the groups, the number of recipients free from ACR in the FK group was significantly higher as compared with the CsA group (P<0.05). Bacterial and viral pneumonias were the major causes of late graft failure in both groups. The mean number of episodes of ACR/100 patient days was significantly fewer in the FK group (1.2) as compared with the CsA group (2.0) (P<0.05). While only one recipient (1/36=3%) in the group treated with CsA remained free from ACR within 120 days of transplantation, 13% (5/38) of the group treated with FK remained free from ACR during this interval (P<0.05). The prevalence of bacterial infection in the CsA group was 1.5 episodes/100 patient days and 0.6 episodes/100 patient days in the FK group. The prevalence of cytomegaloviral and fungal infection was similar in both groups.
Although the presence of bacterial, fungal, and viral infections was similar in the two groups, ACR occurred less frequently in the FK-treated group as compared with the CsA-treated group in the early postoperative period (<90 days). Early graft survival at 30 days was similar in the two groups, but intermediate graft survival at 6 months was better in the FK group as compared with the CsA group.
The purpose of this study was to compare the effects of lumbar stabilization exercises using balls to the effects of general lumbar stabilization exercises with respect to changes in the cross section of the multifidus (MF), weight bearing, pain, and functional disorders in patients with non-specific chronic low back pain. Twelve patients participated in either a 8 week (3 days per week) stabilization exercise program using balls and control group (n = 12). The computer tomography (CT) was used to analyze MF cross-sectional areas (CSA) and Tetrax balancing scale was used to analyze left and right weight bearing differences. Both groups had significant changes in the CSA of the MF by segment after training (p < 0.05) and the experimental group showed greater increases at the L4 (F = 9.854, p = 0.005) and L5 (F = 39. 266, p = 0.000). Both groups showed significant decreases in weight bearing, from 9.25% to 5.83% in the experimental group and from 9.33% to 4.25% in the control group (p < 0.05), but did not differ significantly between the two groups. These results suggests that stabilization exercises using ball can increases in the CSA of the MF segments, improvement in weight bearing, pain relief, and recovery from functional disorders, and the increases in the CSA of the MF of the L4 and L5 segments for patients with low back pain.
Key PointsCompared with the stabilization exercise using a ball and general stabilization exercise increased the CSA of the MF, weight bearing, pain, and functional ability in patients with low back pain.We verified that increases in the CSA of the MF of the L4 and L5 segments and functional ability during the stabilization exercise using a ball.The stabilization exercise using a ball was shown to be an effective exercise method for patients with low back pain in a rehabilitation program by increasing functional ability and the CSA of the MF.
Stabilization exercise; ball; multifidus; cross-sectional area; low back pain
Recent studies suggest a link between brown adipose tissue (BAT) and bone. The purpose of our study was to investigate the effects of BAT on femoral bone structure.
Materials and Methods
We studied 105 patients (19 m, 86 f, mean age 45.5±16.1 y) who underwent F18-FDG positron emission tomography/computed tomography (PET/CT) for benign etiologies (n=20) or follow-up of successfully treated malignancies (n=85); mean time between PET/CT and last form of treatment was 14.8±18.0 months. BAT volume by PET/CT; femoral bone structure by CT (total femoral cross-sectional area (CSA), cortical CSA); thigh muscle CSA and thigh subcutaneous fat CSA by CT were assessed.
There were positive correlations between BAT volume and total femoral CSA and cortical CSA, independent of age, BMI and history of malignancy (P<0.05). BAT volume correlated positively with thigh muscle CSA and thigh fat CSA (p<0.05). When total femoral CSA was entered as a dependent variable and BAT volume, age and BMI as independent variables in a forward stepwise regression model, BAT volume was the only predictor of total femoral CSA. When femoral cortical CSA was entered as a dependent variable and BAT volume, age and BMI as independent variables, BAT volume was the only predictor of femoral cortical CSA.
BAT volume is a positive predictor of femoral bone structure and correlates positively with thigh muscle and subcutaneous fat, possibly mediated by muscle. These results provide further evidence of a positive effect of BAT on bone.
brown adipose tissue (BAT); bone; structure; muscle; fat
OBJECTIVE—To investigate the therapeutic benefit of cyclosporin A (CSA) switching to hydroxychloroquine (HCQ) in patients with rheumatoid arthritis (RA).
METHODS—Thirty four patients with RA who displayed residual inflammation and disability despite partial responses to prior maximal tolerated doses of methotrexate, were included. All were treated with a staged approach using CSA for 24 weeks to induce clinical improvement, followed by HCQ for 16 weeks to maintain the improvement. Seven ACR core set measures were evaluated every four to eight weeks.
RESULTS—During a 40 week open trial, 27/34 patients completed the study. CSA treatment significantly reduced the tender joints score, swollen joints score, visual analogue pain scale, patient's or doctor's global assessment, patient's self assessed disability, and C reactive protein. Compared with the time of entry into the trial, patients who switched from CSA to HCQ still possessed significantly lower levels of most variables, determined at 28, 32, and 40 weeks. According to the ACR 20% improvement definition, 15/27 (56%) patients had improved at 24 weeks after CSA treatment, and 14/27 (52%) remained improved at 16 weeks after the change to HCQ. Frequent side effects, such as hypertrichosis, gastrointestinal trouble, and hypertension, were noted during CSA treatment, but most of these disappeared after switching to HCQ. The mean levels of blood pressure and serum creatinine were significantly increased during CSA treatment, but returned to normal after changing to HCQ.
CONCLUSIONS—The data suggest that CSA switching to HCQ treatment may be an effective strategy for patients with RA partially responding to methotrexate, particularly those with toxicity due to CSA.
The purpose of this study was to determine the difference in cuff pressure which occludes arterial blood flow for two different types of cuffs which are commonly used in blood flow restriction (BFR) research. Another purpose of the study was to determine what factors (i.e., leg size, blood pressure, and limb composition) should be accounted for when prescribing the restriction cuff pressure for this technique. One hundred and sixteen (53 males, 63 females) subjects visited the laboratory for one session of testing. Mid-thigh muscle (mCSA) and fat (fCSA) cross-sectional area of the right thigh were assessed using peripheral quantitative computed tomography. Following the mid-thigh scan, measurements of leg circumference, ankle brachial index, and brachial blood pressure were obtained. Finally, in a randomized order, arterial occlusion pressure was determined using both narrow and wide restriction cuffs applied to the most proximal portion of each leg. Significant differences were observed between cuff type and arterial occlusion (narrow: 235 (42) mmHg vs. wide: 144 (17) mmHg; p = 0.001, Cohen’s D = 2.52). Thigh circumference or mCSA/fCSA with ankle blood pressure, and diastolic blood pressure, explained the most variance in the cuff pressure required to occlude arterial flow. Wide BFR cuffs restrict arterial blood flow at a lower pressure than narrow BFR cuffs, suggesting that future studies account for the width of the cuff used. In addition, we have outlined models which indicate that restrictive cuff pressures should be largely based on thigh circumference and not on pressures previously used in the literature.
Kaatsu; Hypertrophy; Strength; Vascular occlusion training
Trunk muscles, such as the transversus abdominis (TrA) and multifidus, play a key role in lumbopelvic stability, which is important in athletic performance. Asymmetry or imbalance in these and other trunk muscles could result from the specific requirements of the game of Australian rules football.
To determine whether seasonal variations in the sizes of key trunk muscles associated with lumbopelvic stability occur in Australian Football League players.
Patients or Other Participants:
The number of players eligible to participate at each of the 4 time points was 36 at the start of preseason 1 (T1), 31 at end of season 1 (T2), 43 at the end of preseason 2 (T3), and 41 at the start of preseason 3 (T4). The group with data at all 4 time points (n = 20) was used in the analyses and was shown to be representative of the total sample.
Magnetic resonance imaging was used to determine the cross-sectional areas (CSAs) of the multifidus (vertebral levels L2 to L5) and lumbar erector spinae (LES) muscles (L3), as well as the thickness of the TrA and internal oblique (IO) muscles at L3.
Main Outcome Measure(s):
Cross-sectional areas of the multifidus and LES muscles and thickness of the TrA and IO muscles.
By the end of the playing season, results showed 11.1% atrophy for multifidus CSA at L3 and 21% atrophy for TrA thickness at rest. In comparison, the CSA of the LES muscles increased by 3.6%, and the thickness of the IO muscle increased by 11.8% compared with the start of the preseason.
The results indicated an imbalance of the key muscles associated with lumbopelvic stability.
Australian Football League; magnetic resonance imaging; multifidus muscle; transversus abdominis muscle
Using high-resolution ultrasonography (US) to measure the median nerve cross-sectional areas (CSAs) such as in the “inching test” conducted in nerve conduction studies is a valuable tool to assess carpal tunnel syndrome (CTS). However, using this US measurement method to assess the median nerve CSA in diabetic patients with CTS has rarely been reported. Therefore, we used this US measurement method in this study to measure median nerve CSAs and to compare the CSAs of idiopathic, diabetic and diabetic polyneuropathy (DPN) patients with CTS.
124 hands belonging to 89 participants were included and assigned into four groups: control (32), idiopathic (38), diabetic (38) and DPN (16) CTS. In the latter two groups, only patients with mild and moderately severe CTS were included. The median nerve CSAs were measured at 8 points marked as i4, i3, i2, i1, w, o1, o2, and o3 in the inching test. The measured CSAs in each group of participants were compared.
Compared with the CSAs of the control group, enlarged CSAs were found in the idiopathic, diabetic and DPN CTS groups. The CSAs were larger at i4, i3 and i2 in the diabetic CTS group compared to the idiopathic CTS group. The CSAs measured at the i1 and w levels of the DPN CTS group were smaller than those of the diabetic CTS group. In the diabetic CTS group, the cut-off values of CSAs measured at the inlet, wrist crease, and outlet were 15.3 mm2, 13.4 mm2 and 10.0 mm2, respectively, and 14.0 mm2, 12.5 mm2 and 10.5 mm2, respectively, in the DPN CTS group.
Compared with the median nerve CSAs of the control and idiopathic CTS groups, the median nerve CSAs of the diabetic patients with CTS were significantly enlarged. However, compared with the diabetic CTS group, the CSAs were significantly smaller in the DPN CTS group. This US 8-point measurement method can be of value as an important complementary tool for CTS studies and diagnosis among diabetic patients.
Cyclosprin A (CsA) has been widely used clinically to treat the patients who have undergone organ transplantation or acquired autoimmune disease. The purpose of this study is to determine the effects of three different doses of CsA (1.5, 7.5, 15 mg/kg body weight) on the skeletal biomechanical proprieties at different anatomic sites in rats.
Fifty-six male 3-month-old Wistar rats were divided into five groups. Eight rats were randomly chosen as the basal group, while the others were randomly distributed into four groups of 12 animals each. One group was used as controls and received daily subcutaneous injection of 1 ml of saline solution; another three experimental groups were injected subcutaneously with CsA in a daily dose of 1.5, 7.5, and 15 mg/kg body weight respectively for 60 days. The bone biomechanical proprieties, the bone mineral density, as well as the trabecular bone architecture were measured at different anatomic sites, i.e. the lumbar vertebra, the middle femur shaft, and the proximal femur.
CsA therapy at 7.5 and 1.5 mg/kg can significantly reduce the ultimate force, the ultimate stress and the energy absorption per unit of bone volume of the lumbar vertebra, with no effect on the middle femur. CsA therapy at 7.5 mg/kg can significantly reduce the ultimate force, the ultimate stress and the Young's modulus of the femoral neck, but not CsA at 1.5 mg/kg. Furthermore, CsA therapy at 7.5 and 1.5 mg/kg can significantly reduce the bone mineral density of the lumber vertebra and the proximal femur, but have no effect on the middle femur. CsA therapy at 7.5 and 1.5 mg/kg can also significantly reduce the bone volume fraction of the proximal tibia and the lumber vertebra, but has no effect on the cortical thickness of the middle femoral shaft. In the 15 mg/kg CsA group only one rat survived, and the kidney and liver histology of the survived rat showed extensive tissue necrosis.
Long-term use of CsA can weaken the biomechanical properties and thus increase the fracture rate of the lumbar vertebra and the proximal femur. However, CsA therapy has less effect on the middle femur shaft. The effects of CsA on skeleton are site-specific.