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PubMed1982

Trunk muscle strength and low back pain.

The strength of the trunk muscles was measured in a group of young males with low back insufficiency (n=7) and in an age matched (19-21 yrs) healthy control group (n=8). A recently designed new application of the isokinetic technique was used to record maximal torque produced by the trunk muscles during flexion, extension and lateral flexion. Trunk muscle strength was measured during isometric contractions in different trunk positions and during slow isokinetic contractions in the whole range of motion. No significant differences between the groups were observed for trunk extension, lateral flexion or flexion with the centre of rotation at L2-L3 level. However, in the initial part of isokinetic trunk flexion with the pivot point at the hip joint the strength values for the back patients were significantly lower than for the controls. The present results demonstrate the importance of a comprehensive approach to the assessment of trunk muscle strength, including different movement velocities, body positions and pivot points. Further studies are needed to evaluate the significance of the specific weakness observed in dynamic trunk flexion strength in the back patients.

Adult↗
PubMed2000

Postoperative changes in paraspinal muscle thickness after various lumbar back surgery procedures.

Damage to the paraspinal muscle after various lumbar back surgery procedures was evaluated by measuring the paraspinal muscle thickness preoperatively and postoperatively in 89 patients, 61 males and 28 females. There were 42 single interlaminar level procedures (SL group), 13 multiple interlaminar level procedures (ML group), and 34 posterolateral fusion procedures (PLF group). Changes in paraspinal muscle thickness were evaluated at more than 10 months after surgery, because muscle swelling continued as long as 10 months after surgery, and then reduced as the edema subsided. Postoperative serum creatine phosphokinase (CPK) level on postoperative day 2 was also measured. The decrease of paraspinal muscle thickness was significantly larger in the PLF group than in the SL group (-12.9% and -2.7%, respectively, p < 0.02). There was no significant correlation between postoperative serum CPK level and decrease of paraspinal muscle thickness. However, the postoperative elevation of serum CPK level was significantly higher in the PLF group than in the SL and ML groups (979 +/- 114 vs. 292 +/- 45 and 410 +/- 44 IU/l, respectively, p < 0.001). In conclusion, posterolateral fusion is the most invasive procedure of the paraspinal muscles in various lumbar back surgery procedures. Paraspinal muscle damage during lumbar back surgery may be one of the most important factors that causes atrophy of the muscles.

Adult↗
PubMed1993

Local denervation atrophy of paraspinal muscles in postoperative failed back syndrome.

Impairment and disability after back surgery is a common diagnostic and therapeutic problem. For the most part the reasons are unclear. Of 178 patients who had undergone laminectomies 2-5 years earlier, 14 patients with good recovery and 21 patients with poor recovery but no evidence of restenosis on computed tomography were selected by the Oswestry index. According to radiologic, neurophysiologic, and muscle biopsy evidence most patients (13 of 15 studied) suffering from the severe postoperative failed back syndrome had dorsal ramus lesions in one or more segments covered by the scar and local paraspinal muscle atrophy at the corresponding segments. Disturbed back muscle innervation and loss of muscular support leads to the disability and increased biomechanical strain and might be one important cause to the failed back syndrome. It may be possible to develop operating techniques that save back muscle innervation better than the usual ones.

Adult↗
PubMed1998

Murray L. Barr Award Lecture. Studies of the dynamics of skeletal muscle regeneration: the mouse came back!

Regeneration of skeletal muscle tissue includes sequential processes of muscle cell proliferation and commitment, cell fusion, muscle fiber differentiation, and communication between cells of various tissues of origin. Central to the process is the myosatellite cell, a quiescent precursor cell located between the mature muscle fiber and its sheath of external lamina. To form new fibers in a muscle damaged by disease or direct injury, satellite cells must be activated, proliferate, and subsequently] fuse into an elongated multinucleated cell. Current investigations in the field concern modulation of the effectiveness of skeletal muscle regeneration, the regeneration-specific role of myogenic regulatory gene expression distinct from expression during development, the impact of growth and scatter factors and their respective receptors in amplifying precursor numbers, and promoting fusion and maturation of new fibers and the ultimate clinical therapeutic applications of such information to alleviate disease. One approach to muscle regeneration integrates observations of muscle gene expression, proliferation, myoblast fusion, and fiber growth in vivo with parallel studies of cell cycling behaviour, endocrine perturbation, and potential biochemical markers of steps in the disease-repair process detected by magnetic resonance spectroscopy techniques. Experiments on muscles from limb, diaphragm, and heart of the mdx dystrophic mouse, made to parallel clinical trials on human Duchenne muscular dystrophy, help to elucidate mechanisms underlying the positive treatment effects of the glucocorticoid drug deflazacort. This review illustrates an effective combination of in vivo and in vitro experiments to integrate the distinctive complexities of post-natal myogenesis in regeneration of skeletal muscle tissue.

Animals↗
PubMed1988

[Studies on the tendinous compartments of the extensor muscles on the back of the human hand and their tendon sheaths. I].

In 47 dissected right and left hands of adults of both sexes, kept in a moist condition, significant practical-clinical investigations of the transitional zone between forearm and hand were undertaken. In particular it was sought to determine the characteristic sizes of the extensor retinaculum, the osteofibrous tunnels, the insertion tendons of the hand and finger extensor muscles, and their tendon sheaths. Together with the palmar carpal ligament, the 2 to 3 cm wide extensor retinaculum annularly surrounds the whole circumference of the carpus. It extends obliquely from radial-proximal to ulnar-distal and conducts the extensor tendons over the carpal articulations. According to recent studies, it is divided into a superficial and a deep fibrous layer. From the undermost surface, vertical and oblique septa run to the plane of the forearm and carpal bones. They separate the fibrous portion of the 6 tendinous compartments of the dorsum manus. In 8.5% of cases, an accessory and completely independent tunnel of the extensor pollicis brevis muscle exists in the material investigated, and in 2.2% of cases, there is an additional tunnel for the extensor carpi radialis muscle. Hence, one occasionally finds 8 separate osteofibrous gliding compartments for the extensor muscles in the dorsal hand region. The longest tunnel belongs, as a rule, to the extensor digiti minimi muscle, whilst the widest pertains to the extensor digitorum muscle. Within the tunnel and also proximal and distal to it, the extensor tendons are surrounded by synovial sheaths. Because of its wide encroachment on the dorsum of the hand, the insertion tendon of the extensor digiti minimi muscle possesses the longest tendon sheath, measuring 68.8 mm. The next longest sheath, that of the extensor pollicis longus muscle, which measures 56.2 mm, begins further proximal to the gap of the radiocarpal articulation. In 12.8% of cases, there are divided sheaths of the abductor pollicis longus and of the extensor pollicis brevis muscle. The tendon sheath of both extensor carpi radiales muscles is frequently divided into 2 compartments which, in 2/3 of cases, communicate. The compartment of the extensor carpi radialis brevis muscle, in 91.5% of cases, shares a window-like opening with the roof of the synovial vagina of the extensor pollicis longus muscle. The tendon sheath of the long extensor muscles of the fingers originates 5 mm proximal to the forearm border of the extensor retinaculum and has a communal recess. The IVth tendon sheath opens distally and splays out in a glove-like manner to some distal recesses.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

The effect of back belts on lumbar muscle fatigue.

STUDY DESIGN: An experiment was conducted to investigate the effect of wearing a weight lifting belt on the endurance and fatigue characteristics of the extensor muscles of the spine. OBJECTIVE: To evaluate the effectiveness of back belts in preserving the endurance characteristics of the spinal musculature. SUMMARY OF BACKGROUND DATA: Previous studies have investigated the use of back belts in increasing intra-abdominal pressure and thus increasing the stabilization of the spine. Other studies have looked at the association of low back disability and wearing back belts. No study has examined the relationship between wearing back belts and measures of spinal muscle fatigue and endurance. METHODS: Thirteen male industrial workers performed a lifting and lowering task from the floor to a 76.2 cm height at 4.3 min-1 2 days a week for 4 weeks. The load was psychophysically determined and averaged 28.1 kg for a total of 28.9 metric tons moved in 4 hours. Subjects lifted for 1, 2, 3, and 4 hours, respectively, for the first 4 days of the experiment. These were considered training days. During the last 4 days, subjects lifted for 4 hours per day; 2 days with a back belt, and 2 days without a back belt. Maximum isokinetic endurance of the extensors was measured for 50 repetitions (5 sets of 10 repetitions) at the end of 4 hours of lifting. Median frequencies of the electromyographic signal from six locations over the back extensors were measured for 30 seconds at 80% of maximum isometric voluntary contraction after 4 hours of lifting. RESULTS: There were no significant differences in maximum isokinetic endurance, or in the slope of median frequency, between lifting with a back belt and lifting without a back belt. Similarly, a modified Borg scale and a postexperiment survey question were unable to distinguish between wearing a back belt and not wearing a back belt. CONCLUSION: There were no significant differences in maximum isokinetic endurance and electromyographic spectral parameters of the back extensor muscles as a result of wearing a back belt during heavy lifting and lowering tasks.

Adult↗
PubMed1998

[Transfer of posterior tibial muscle to the back of the foot: an original procedure for fixing the transplant].

PURPOSE OF THE STUDY: The purpose of the study was to adjust a palliative transfer using the Tibialis Posterior (TP) tendon in case of foot dorsiflexion palsy. The surgical procedure emphasized some functional features, in an attempt to lessen parasitical motion of the foot in abduction or in adduction when patients bear the ankle joint in dorsiflexion, and to strengthen the transfer. MATERIAL AND METHODS: The surgical technique was carried out four times in patients, with a follow-up of six to eighteen months. One 20 cm long leg incision, on the antero-lateral part of tibia, up to the retinaculum of extensors tendons, allowed a section of Tibialis Anterior (TA) tendon as proximal as possible, and an aperture through the tibiofibular fascia in its lower third. One 15 cm long leg incision, along the postero-medial edge of the tibia, toward medial malleolus, allowed a release of the TP tendon after distal section. The tendon was rerouted across the former fascia aperture. One 6 cm foot medial incision face to navicular bone, where the TA tendon was thoroughly extracted and diverted, close to the sole side of the medial cuneiforme, and the two medial metatarsal bones. One 5 cm foot dorsal incision was performed, opposite to the 2d intermetatarsal space, where the diverted TA tendon end was recovered and pulled along a tunnel beneath the retinaculum of extensors. It was thus sutured, with a satisfactory tension to the TP tendon transferred across the tibiofibular fascia. Weight bearing in a short leg cast was allowed. RESULTS, DISCUSSION, CONCLUSION: In the four cases, the results fulfilled the goal, with a satisfactory evaluation of the efficacy of the transfer, even the TA tendon was once intentionally diverted through the 1st metatarsal space instead of the second one, without any damage for the vessels pedicle. Among the widespread use of TP tendon, we think that a more neutral position of the tendon should be adopted with a curse coming along the extension of the leg axis, to the 2d intermetatarsal space. The more distally the transfer may be bound, the much efficient it will be. Obviously, there is no change in a correct automatic use of the transfer in gait. Even though it requires more experience and much longer follow-up time, this technique ensure a reliable and comfortable attachment of the transferred tendon, by a tendon-to-tendon suture, and secure a better restored foot dorsiflexion.

Follow-Up Studies↗
PubMed1995

Isodynamic evaluation of trunk muscles and low-back pain among workers in a steel factory.

A cross-sectional study was conducted to explore the relationship between dynamic parameters of trunk muscle strength and the occurrence of low-back pain (LBP). Isodynamic strength measurements were performed among 31 male maintenance workers with spells of low-back pain in the past 12 months and 28 maintenance workers without a history of low-back pain. In general, workers with low-back pain showed a lower trunk muscle performance than the workers without low-back pain. Only the measures of torque during lateral movement differed significantly between both groups. Regression analysis revealed the importance of the nature of low-back pain for trunk muscle strength. Most parameters of trunk muscle strength were significantly decreased among workers with chronic low-back pain of a rather severe nature, showing reductions from 18% to 50%. None of the work-related risk factors for low-back pain contributed significantly to the prediction of trunk strength measures. The study suggests that isodynamic evaluation of trunk muscle strength may assist in determining objective measures for the severity of low-back pain rather than in evaluating a subject's capability of successfully coping with a specific work load.

Adult↗
PubMed1994

Some endurance measures in persons with chronic low back pain.

Muscle fatigue and lack of endurance are complaints of persons with chronic low back pain, but there are no standard ways to assess endurance in this population. The purposes of this study were to examine three measures of endurance; to determine relationships of these measures to each other; and to describe effects of gender, obesity, smoking, and self-reported fitness on the clinical measures. The measures of endurance selected were not dependent on maximal voluntary muscular contractions. They were the Sorensen test, median frequency decline of selected muscles, and a submaximal bicycle ergometer test. Thirty-five consenting individuals who were referred for treatment answered questions about their daily exercise prior to being tested. Repeatability of the Sorensen test holding time and of the slope measure of decline in the median frequencies was acceptable for subjects who reported a higher activity level. The decline of the median frequency in the biceps femoris muscles correlated with holding time of the Sorensen test. Smoking, gender, or obesity level did not affect test results on any of the endurance measures. Subjects who reportedly were more active achieved significantly higher scores on the Sorensen test. The importance of controlling for self-perception of activity in physical testing is discussed.

Adult↗
PubMed2004

Chronic low back pain-associated paraspinal muscle dysfunction is not the result of a constitutionally determined "adverse" fiber-type composition.

STUDY DESIGN: Investigative case control study. OBJECTIVES: To determine whether excessive paraspinal muscle fatigue in chronic low back pain results from a paucity of muscle type I fiber content. SUMMARY OF BACKGROUND DATA: Paraspinal muscle function is vital for spinal protection. Prospective studies suggest that excessive paraspinal muscle fatigability may increase risk of first-time low back pain. As contractile performance of the paraspinal muscles is governed by their constitutionally determined fiber composition, the question arises whether a constitutionally determined "adverse" composition could predispose to low back pain through impaired spinal protection. METHODS: Thirty-five male patients with chronic low back pain were compared with 32 male control patients of similar age and anthropometry. During Sorensen and 60% of maximum voluntary isometric contraction fatigue tests, median frequency declines in the paraspinal muscle surface electromyograph signal were monitored and correlated with muscle histomorphometry. RESULTS: Patients were weaker than controls during maximum voluntary isometric contractions (84.47 [28.44]vs. 98.74 [18.11] kg, respectively; P = 0.02) and more fatigable during their Sorensen tests (endurance time 105.29 [28.53]vs. 137.50 [40.38] sec, respectively; P < 0.01). There were no between-group differences in median frequency declines during the Sorensen (-0.37 [0.16]vs. -0.36 [0.12]%.sec) or 60% maximum voluntary isometric contraction (-0.42 [0.31]vs. -0.51 [0.29]%.sec) tests, for patients and controls, respectively. There were no between-group differences in the percent number of paraspinal muscle type I fibers (64 [11]vs. 64 [9]%) or the percent area occupied by type I fibers (67 [11]vs. 69 [9]%), for patients and controls, respectively. Type I and II muscle fiber narrow diameters were similar for both groups. CONCLUSION: In the patients with chronic low back pain tested, their associated paraspinal muscle dysfunction was not the result of a constitutionally determined "adverse" fiber type composition.

Adult↗