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PubMed2001

Sensory-motor control of the lower back: implications for rehabilitation.

Although low back pain (LBP) is a widespread and disabling health problem, there is a lack of evidence based medicine with respect to its treatment and rehabilitation. A major reason for this is the poor understanding of the underlying mechanisms of the LBP syndromes. In an attempt to fill this gap, the present review article provides an overview of the sensory-motor control aspects of trunk stabilization and postural control of the trunk, and how they may relate to the evolution of LBP. In particular, the anatomy and physiology of the sensory-motor control mechanisms of the trunk muscles that contribute to general and segmental stability of the lumbar spine will be elucidated. Furthermore, a brief overview of current theories of postural control will be provided with respect to spinal stabilization. Finally, a concept of the pathophysiological changes within the sensory-motor control mechanisms of the lumbar spine in the presence of muscle injury and pain will be presented. The impact of pain and muscle injury on the muscular support for the lumbar motion segment will be discussed along with the deficits in neuromuscular control in LBP patients with decreased segmental lumbar stability.

Abdominal Muscles↗
PubMed2005

A hypothesis of chronic back pain: ligament subfailure injuries lead to muscle control dysfunction.

Clinical reports and research studies have documented the behavior of chronic low back and neck pain patients. A few hypotheses have attempted to explain these varied clinical and research findings. A new hypothesis, based upon the concept that subfailure injuries of ligaments (spinal ligaments, disc annulus and facet capsules) may cause chronic back pain due to muscle control dysfunction, is presented. The hypothesis has the following sequential steps. Single trauma or cumulative microtrauma causes subfailure injuries of the ligaments and embedded mechanoreceptors. The injured mechanoreceptors generate corrupted transducer signals, which lead to corrupted muscle response pattern produced by the neuromuscular control unit. Muscle coordination and individual muscle force characteristics, i.e. onset, magnitude, and shut-off, are disrupted. This results in abnormal stresses and strains in the ligaments, mechanoreceptors and muscles, and excessive loading of the facet joints. Due to inherently poor healing of spinal ligaments, accelerated degeneration of disc and facet joints may occur. The abnormal conditions may persist, and, over time, may lead to chronic back pain via inflammation of neural tissues. The hypothesis explains many of the clinical observations and research findings about the back pain patients. The hypothesis may help in a better understanding of chronic low back and neck pain patients, and in improved clinical management.

Animals↗
PubMed1990

Functional organization within the medullary reticular formation of intact unanesthetized cat. II. Electromyographic activity evoked by microstimulation.

1. The present study has examined the detailed organization of the medullary reticular formation (MRF) as revealed by microstimulation (33-ms trains of 0.2-ms duration pulses at 330 Hz and 35 microA or less) in the intact, chronically implanted, unanesthetized cat. Stimulus-locked electromyographic (EMG) responses were recorded from flexors and extensors of each of the four limbs, as well as bilaterally from muscles of the neck and back, during stimulation of the same 592 loci that formed the basis of the preceding article. 2. The thresholds of the responses were different for each group of muscles, with, on the average, the neck muscles being activated at the lowest range of currents, 13.8-16.5 microA; forelimb muscles at 16.9-17.9 microA; back muscles at 25.4-25.7 microA; and hindlimb muscles at 21.1-25.7 microA. 3. Whereas stimulation within the MRF evoked movement of the head only to the stimulated side (preceding article), analysis of the EMG responses showed there was frequently bilateral activation of the neck muscles. Similarly, even though stimulation produced predominantly ipsilateral elbow flexion and contralateral elbow extension, most loci caused cocontraction of antagonistic muscles at these joints. Cocontraction was also frequently observed for the hindlimbs. Reciprocal activation of antagonistic muscles was less frequent but was observed in the ipsilateral forelimb as well as in both hindlimbs; it was never observed in the contralateral forelimb. 4. Although excitatory responses were observed from widespread regions for all of the muscles under study, those regions of the MRF that evoked the strongest responses in each muscle showed a large degree of segregation. Muscles of the ipsilateral forelimb were most strongly activated from the rostrodorsal MRF, whereas muscles of the contralateral forelimb were most strongly effected by stimulation caudoventrally. Muscles of the hindlimbs were more strongly activated from the rostral brain stem, although with some exceptions. Responses in axial muscles were evoked from widespread regions of the brain stem but were concentrated further caudally than were the limb muscles. 5. Excitatory responses were much more prevalent than inhibitory responses and were evoked from all regions of the MRF, including the most caudal and ventral areas. The shortest latency responses in each track were, on the average, as follows: 6.6-8.8 ms for the neck; 11.2-13.4 ms for the forelimbs; 13.8-14.2 ms for the back; and 15.9-17.2 ms for the hindlimbs. Inhibitory responses were also evoked from widely distributed regions, which were intermingled with those loci evoking excitatory responses.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1980

Evaluation and prediction of back pain during military field service.

Questions regarding back pain in different body positions and earlier sick-listing due to back disorders have been answered by 5093 men aged 23--47 (average age 37) who were about to do military field service. Fifty-three % reported that they had had back pain at some time and 14% stated that they had been sick-listed for more than one month in all due to back troubles. A subsample was subjected to a standardized physical examination of the back, average examination time 9 min, and the frequency and location of pain, stiffness of other impairments are given. Subjects who experienced back pain during the field service and whose military post was physically heavier than their civilian occupation had on an average lower isometric strength in abdominal muscles as well as in back muscles than other subjects. The physical examination of the lumbar spine was more efficient in separating subjects who experienced back pain during military field service, than information on earlier sick-listing due to back troubles and heaviness of the military post as compared to civilian occupation.

Abdominal Muscles↗
PubMed1996

Muscular response to sudden load. A tool to evaluate fatigue and rehabilitation.

STUDY DESIGN: Subjects were exposed to fatiguing and restorative interventions to assess their response to sudden loads. OBJECTIVES: To investigate the erector spinae and rectus abdominis response characteristics to "sudden load" and the effect of fatigue and rehabilitation. SUMMARY OF BACKGROUND DATA: Unexpected loads which people often experience, can lead to high forces in the spine and may be a cause of low back injury. METHODS: Muscle responses to sudden load were mediated by fatigue, walking, expectation, method of load application, exposure to vibration, and cognitive-behavioral rehabilitation in patients with chronic low back pain. A novel technique, perfected in this work, called wavelet analysis, was used to analyze these data. RESULTS: Reaction time was affected by fatigue and expectation. Vibration exposure significantly increased the muscle response time. Walking was able to ameliorate that effect. Back muscles responded differently, depending on whether loads were applied to the back through the hands or through the trunk. Electromyographic reaction time and magnitude decreased in patients after a 2-week rehabilitation program. CONCLUSIONS: Sudden loads can exacerbate fatigue effects. Walking after driving reduces the risk to the back caused by handling unpredictable loads. Vibration exposure guidelines should be more conservative. Patients have longer response times than healthy subjects, but patients can improve their response to sudden loads via rehabilitation. Patients exhibit a flexion-extension oscillation at 5 Hz in response to a sudden load, suggesting that the 5-Hz, seated, natural frequency observed during whole-body vibration may result from neurophysiologic control limits.

Adult↗
PubMed1998

[Posterior thoracic reconstruction with latissimus dorsi flap after partial amputation of the latissimus dorsi muscle for sarcoma of the back. Report of four cases].

Malignant fibrous histiocytomas (MFH) arising from the subcutaneous tissues of the posterior thoracic wall require wide, but usually non-transfixing, resection to ensure adequate resection margins, the only way to reduce the local recurrent rate. Due to its size and position, the Latissimus dorsi muscle usually requires partial amputation. However, its vascular anatomy allows it to be used as a musculocutaneous flap of the residual muscle to fill the defects created. Four clinical cases are reported. This technique reduces the complication rate and simplifies the postoperative course.

Adult↗
PubMed1985

Identical distribution of fluorescently labeled brain and muscle actins in living cardiac fibroblasts and myocytes.

We have investigated whether living muscle and nonmuscle cells can discriminate between microinjected muscle and nonmuscle actins. Muscle actin purified from rabbit back and leg muscles and labeled with fluorescein isothiocyanate, and nonmuscle actin purified from lamb brain and labeled with lissamine rhodamine B sulfonyl chloride, were co-injected into chick embryonic cardiac myocytes and fibroblasts. When fluorescence images of the two actins were compared using filter sets selective for either fluorescein isothiocyanate or lissamine rhodamine B sulfonyl chloride, essentially identical patterns of distribution were detected in both muscle and nonmuscle cells. In particular, we found no structure that, at this level of resolution, shows preferential binding of muscle or nonmuscle actin. In fibroblasts, both actins are associated primarily with stress fibers and ruffles. In myocytes, both actins are localized in sarcomeres. In addition, the distribution of structures containing microinjected actins is similar to that of structure containing endogenous F-actin, as revealed by staining with fluorescent phalloidin or phallacidin. Our results suggest that, at least under these experimental conditions, actin-binding sites in muscle and nonmuscle cells do not discriminate among different forms of actins.

Actins↗
PubMedDate not supplied

[Reconstruction-restorative surgeries of mastitis sequelae].

Experience of performance of reconstruction-restorational operations in 14 patients with consequences of postnatal mastitis (PM) was analyzed. In 2 observations the silicon endoprosthesis were applied, in 11--the musculocutaneous flap using broadest muscle of the back (BMB) and straight abdominal muscle, in 3--combination of both, BMB and endoprosthesis. Immediate and late results are good. Reconstruction of mammary gland using, constitutes the operation of choice because of near location of donor site, satisfactory blood supply and plasticity needed.

Adult↗
PubMed2006

Spinal muscle evaluation in healthy individuals and low-back-pain patients: a literature review.

This article reviews available techniques for spinal muscle investigation, as well as data on spinal muscles in healthy individuals and in patients with low back pain. In patients with chronic low back pain, medical imaging studies show paraspinal muscle wasting with reductions in cross-sectional surface area and fiber density. In healthy individuals, the paraspinal muscles contain a high proportion of slow-twitch fibers (Type I), reflecting their role in maintaining posture. The proportion of Type I fibers is higher in females, leading to better adaptation to aerobic exertion compared to males. Abnormalities seen in paraspinal muscles from patients with chronic low back pain include marked Type II fiber atrophy, conversion of Type I to Type II fibers, and an increased number of nonspecific abnormalities. Limited data are available from magnetic resonance spectroscopy used to investigate muscle metabolism and from near infrared spectroscopy used to measure oxygen uptake by the paraspinal muscles. Surface electromyography in patients with chronic low back pain shows increased paraspinal muscle fatigability, often with abolition of the flexion-relaxation phenomenon.

Electromyography↗
PubMed2004

Needleless in vivo gene transfer into muscles by jet injection in combination with electroporation.

Previously, we have established an in vivo electroporation method for gene transfer into muscle by injection of DNA with a needle followed by electric pulse delivery using needle-type electrodes and proved that this method is effective for the systemic delivery of cytokines. To perform the needleless gene delivery, we combined jet injection of DNA with electroporation using plate-type electrodes. For delivery of beta-galactosidase- and enhanced green fluorescent protein (EGFP)-expressing plasmids into muscles, there was no significant difference between the previous needle-mediated method and the newly developed jet-injection method. When pCAGGS-IL-5 was introduced into tibialis anterior, quadricipital and back sural muscles by this new method, the serum IL-5 levels reached 3.4 +/- 0.9, 5.7 +/- 1.7 and 8.4 +/- 2.7 ng/ml at day 5, respectively. Although the peak values of IL-5 achieved by the jet-injection method in these muscles were lower than that of the highest value achieved by needle-mediated gene delivery into anterior tibial muscle, this new method could deliver plasmid into relatively large muscles with better efficiency than the needle-mediated method. Thus the jet-injection method provides a useful means of gene delivery into large muscles, which is essential for future use in human gene therapy.

Animals↗
PubMed2004

EMG recovery and ratings after back extensor fatigue in patients with lumbar disc herniation and healthy subjects.

This prospective study aimed to examine whether patients with lumbar disc herniation, before and after surgery, showed impaired recovery from fatigue measured with EMG and subjective ratings as compared to healthy subjects. Forty-three patients due for, and after, lumbar disc surgery and 60 healthy subjects were fatigued using a modified Sørensen's test. Recovery of back extensor muscles was assessed using electromyography and the Borg scale ratings at 1, 2, 3, and 5 minutes of recovery, and was further analyzed using an exponential time-dependence model. The patients completed four questionnaires: the Oswestry, the Roland-Morris, a self-efficacy scale and the SF-36. The exponential time-dependence model was successful for 14 of the 43 patients and 57 of the 60 healthy subjects. The patients for whom the model succeeded had significantly better scores on the questionnaires than those for whom the model was unsuccessful. Specific items related to standing and lifting were identified. The patients' recovery was impaired compared to the healthy subjects, as determined by use of the exponential time-dependence model. The combination of fatigue and recovery measures was reflected in the questionnaire scores and is therefore important for evaluating patients with lumbar disc herniation.

Adult↗
PubMed1999

Low back strengthening for the prevention and treatment of low back pain.

PURPOSE: Chronic low back pain (CLBP) remains one of the most difficult and costly medical problems in the industrialized world. A review of nineteenth and early twentieth century spine rehabilitation shows that back disorders were commonly treated with aggressive and specific progressive resistance exercise (PRE). Despite a lack of scientific evidence to support their efficacy, therapeutic approaches to back rehabilitation over the past 30 yr have focused primarily upon passive care for symptom relief. Recent spine rehabilitation programs have returned to active reconditioning PRE centered around low back strengthening to restore normal musculoskeletal function. Research has shown that lumbar extension exercise using PRE significantly increases strength and decreases pain in CLBP patients. It appears that isolated lumbar extension exercise with the pelvis stabilized using specialized equipment elicits the most favorable improvements in low back strength, muscle cross-sectional area, and vertebral bone mineral density (BMD). These improvements occur with a low training volume of 1 set of 8 to 15 repetitions performed to volitional fatigue one time per week. CLBP patients participating in isolated lumbar extension PRE programs demonstrate significant reductions in pain and symptoms associated with improved muscle strength, endurance, and joint mobility. Improvements occur independent of diagnosis, are long-lasting, and appear to result in less re-utilization of the health care system than other more passive treatments. Low back strengthening shows promise for the reduction of industrial back injuries and associated costs.

Back Injuries↗
PubMed1976

Spinal muscle in scoliosis. Comparison of normal and scoliotic rabbits.

Spinal muscle biopsies from 7 rabbits with experimentally-produced scoliosis and from 4 normal control rabbits, were examined histologically and histochemically. One scoliotic rabbit showed selective Type 2 fibre atrophy in its muscles, but in general there was no difference between the normal and the scoliotic rabbits. The percentage area of muscle occupied by Type 1 and Type 2 fibres was determined using a computer controlled microscope. There was no asymmetry in the muscles of either the normal or the scoliotic rabbits on the two sides of the spine. These results suggest that the abnormalities and asymmetry of fibre type proportions reported in human scoliotic muscles are not a consequence of the scoliosis. Within the limits of the study, it is suggested that the abnormalities reported in the muscles of human scoliotic patients are at least an important factor in the causation of "idiopathic" scoliosis.

Animals↗
PubMed1991

[The choice of the extent of the surgical intervention in patients with soft-tissue tumors of the trunk].

Data on 145 cases of soft-tissue tumor of the trunk were analysed. Tumor was located on the chest or back in 81 patients and deep in the anterior abdominal wall--in 64. When intramuscular sarcoma is removed, a 2-3-cm margin should be left around the palpable mass. Five-year survival in the entire group of patients with tumors of the chest and back was 59.4% +/- 2.4. Five out of ten cases with tumor of the abdominal wall survived over 5 years.

Abdominal Muscles↗