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PubMed2006

Assessment of neuromuscular and haemodynamic activity in individuals with and without chronic low back pain.

BACKGROUND: Biering-Sørenson (1984) found that individuals with less lumbar extensor muscle endurance had an increased occurrence of first episode low back pain. As a result, back endurance tests have been recommended for inclusion in health assessment protocols. However, different studies have reported markedly different values for endurance times, leading some researchers to believe that the back is receiving support from the biceps femoris and gluteus maximus. Therefore, this study was designed to examine the haemodynamic and neuromuscular activity of the erector spinae, biceps femoris, and gluteus maximus musculature during the Biering-Sørenson Muscular Endurance Test (BSME). METHODS: Seventeen healthy individuals and 46 individuals with chronic low back pain performed the Biering-Sørenson Muscular Endurance Test while surface electromyography was used to quantify neuromuscular activity. Disposable silver-silver-chloride electrodes were placed in a bipolar arrangement over the right or left biceps femoris, gluteus maximus, and the lumbosacral paraspinal muscles at the level of L3. Near Infrared Spectroscopy was used simultaneously to measure tissue oxygenation and blood volume changes of the erector spinae and biceps femoris. RESULTS: The healthy group displayed a significantly longer time to fatigue (Healthy: 168.5s, LBP: 111.1s; p < or = 0.05). Significant differences were shown in the median frequency slope of the erector spinae between the two groups at 90-100% of the time to fatigue while no significant differences were noted in the haemodynamic data for the two groups. CONCLUSION: Although the BSME has been recognized as a test for back endurance, individuals with chronic LBP appear to incorporate a strategy that may help support the back musculature by utilizing the biceps femoris and gluteus maximus to a greater degree than their healthy counterparts.

Journal Article↗
PubMed1999

Reactive muscle firing of anterior cruciate ligament-injured females during functional activities.

OBJECTIVE: The high incidence of noncontact anterior cruciate ligament (ACL) injuries in females has attracted research to investigate the capacity of muscles to reflexively protect the knee joint from capsuloligamentous injury. Numerous reflex pathways link mechanoreceptors in the ACL with contractile fibers in the quadriceps and hamstring muscles. Loads placed on the ACL modify reactive muscle activity through the feed-back process of neuromuscular control and are critical for dynamic muscular stabilization. Noncontact ACL injuries may be the result of aberrations in reactive muscle firing patterns. Therefore, compensatory muscle activation strategies must be employed if functional stability is to be restored after injury or surgical reconstruction. The purpose of our study was to compare the amplitude of reactive muscle activity in females with ACL-deficient (ACLD), ACL-reconstructed (ACLR), and control knees during functional activities. DESIGN AND SETTING: Female volunteer subjects were stratified into groups based on the status of their ACLs. Each subject performed 4 functional activities, bilaterally, during a single test session. SUBJECTS: Twenty-four female subjects participated in this study (ACLD = 6, ACLR = 12, control = 6). MEASUREMENTS: Integrated electromyographic (IEMG) data were collected with surface electrodes from the vastus medialis, vastus lateralis, medial hamstring, and lateral hamstring during downhill walking (15 degrees , 0.92 m/s), level running (2.08 m/s), and hopping and landing from a jump (20.3 cm). IEMG was normalized to the mean amplitude of 3 to 6 consecutive test repetitions. The mean area and peak IEMG of a 250-millisecond period after ground contact was used to represent reactive muscle activity. Side-to-side differences were determined using dependent t tests, and group differences were determined using a one-way analysis of variance. RESULTS: During running, the ACLD group demonstrated significantly greater area and peak IEMG activity in the medial hamstring in comparison with the ACLR group and greater peak activity in the lateral hamstring when compared with the control group. The ACLD group also demonstrated greater peak activity in the vastus medialis and a smaller area of IEMG activity in the lateral hamstring than the control group during running. During landing, the ACLD group demonstrated significantly less area of IEMG activity in the vastus lateralis when compared with the control group. No significant differences were identified between the ACLR and control groups, nor were side-to side differences revealed. CONCLUSIONS: Our results suggest that adaptations occur in the reactive muscle activity of ACLD females during functional activities. Strategies to minimize the anterior tibial translation in response to joint loading included increased hamstring activity and quadriceps inhibition. The reactive muscle activity exhibited in ACLD subjects is presumably an attempt to regain functional stability through the dynamic restraint mechanism. The absence of side-to-side differences suggests that these adaptations occur bilaterally after ACL injury.

Journal Article↗
PubMed1995

Pocket-size, portable surface EMG device in the differentiation of low back pain patients.

The relevance of surface EMG of the paraspinal muscles measured by a portable, pocket-size device with a special amplifier was evaluated in different low back pain groups. Patients with only local low back pain had significantly higher EMG activities than those with unilateral radiating pain without verified disc herniation, those with verified disc herniation, and controls, but there were no differences between the latter three groups. Pain clearly modified paravertebral muscle activity, as the patients experiencing pain during the recording showed significantly higher EMG activities than those with no pain. It is concluded that surface EMG is a valid tool for indirectly assessing pain in low back pain patients but not for classification into different diagnostic groups.

Adolescent↗
PubMedDate not supplied

A clinical and pharmacologic review of skeletal muscle relaxants for musculoskeletal conditions.

Muscle strains and other musculoskeletal disorders (MSDs) are a leading cause of work absenteeism. Muscle pain, spasm, swelling, and inflammation are symptomatic of strains. The precise relationship between musculoskeletal pain and spasm is not well understood. The dictum that pain induces spasm, which causes more pain, is not substantiated by critical analysis. The painful muscle may not show EMG activity, and when there is, the timing and intensity often do not correlate with the pain. Clinical and physiologic studies show that pain tends to inhibit rather than facilitate reflex contractile activity. The decision to treat and choice of therapy are largely dictated by the duration, severity of symptoms, and degree of dysfunction. Trigger point injections are sometimes used with excellent results in the treatment of muscle spasm in myofacial pain and low-back pain. NSAIDs are used with much greater frequency than oral skeletal muscle relaxants (SMRs) or opioids in the treatment of acute MSDs. Unfortunately, remarkably little sound science guides the choice of drug for the treatment of acute, uncomplicated MSDs, and the evaluation of efficacy of one agent over another is complicated by numerous factors. Only a limited number of high-quality, randomized, controlled trials (RCTs) provide evidence of the effectiveness of NSAIDs or SMRs in the treatment of acute, uncomplicated MSDs. The quality of design, execution, and reporting of trials for the treatment of MSDs needs to be improved. The combination of an SMR and an NSAID or COX-2 inhibitor or the combination of SMR and tramadol/acetaminophen is superior to single agents alone.

Acute Disease↗
PubMedDate not supplied

Severe lumbar back pain following epidural injection of local anesthetic for epidural anesthesia. Case report and literature review.

BACKGROUND AND OBJECTIVES: An epidural anesthetic was planned for a 75-year-old man scheduled for elective femoral-popliteal bypass grafting. METHODS: Severe and persistent back pain and posterior thigh muscle spasm abruptly began 10 minutes after epidural injection of mepivacaine. RESULTS: Signs of impending or evolving neurologic injury completely resolved shortly thereafter. CONCLUSIONS: The worst case scenarios, epidural hematoma and unintentional epidural injection of an irritant, are discussed along with other differential diagnoses. The literature is reviewed to gain insight into this unusual clinical presentation.

Aged↗
PubMed1996

Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of transversus abdominis.

STUDY DESIGN: The contribution of transversus abdominis to spinal stabilization was evaluated indirectly in people with and without low back pain using an experimental model identifying the coordination of trunk muscles in response to a disturbances to the spine produced by arm movement. OBJECTIVES: To evaluate the temporal sequence of trunk muscle activity associated with arm movement, and to determine if dysfunction of this parameter was present in patients with low back pain. SUMMARY OF BACKGROUND DATA: Few studies have evaluated the motor control of trunk muscles or the potential for dysfunction of this system in patients with low back pain. Evaluation of the response of trunk muscles to limb movement provides a suitable model to evaluate this system. Recent evidence indicates that this evaluation should include transversus abdominis. METHODS: While standing, 15 patients with low back pain and 15 matched control subjects performed rapid shoulder flexion, abduction, and extension in response to a visual stimulus. Electromyographic activity of the abdominal muscles, lumbar multifidus, and the surface electrodes. RESULTS: Movement in each direction resulted in contraction of trunk muscles before or shortly after the deltoid in control subjects. The transversus abdominis was invariably the first muscle active and was not influenced by movement direction, supporting the hypothesized role of this muscle in spinal stiffness generation. Contraction of transversus abdominis was significantly delayed in patients with low back pain with all movements. Isolated differences were noted in the other muscles. CONCLUSIONS: The delayed onset of contraction of transversus abdominis indicates a deficit of motor control and is hypothesized to result in inefficient muscular stabilization of the spine.

Adult↗
PubMed2002

M-mode ultrasound: a reliable measure of transversus abdominis thickness?

OBJECTIVE: The purpose of this study was to establish a reliable method for measuring transversus abdominis thickness in asymptomatic human subjects in supine lying, standing and walking. DESIGN AND METHODS: This was a single operator reliability study using ultrasound imaging to measure 22 subjects on three separate occasions. A purpose built high-density foam reinforced belt was used to house and position the transducer over the mid-point of the transversus abdominis. Each subject was imaged in supine, standing, and treadmill walking at 3 kph. Intraclass correlation coefficients and standard error of measurement analysis were used to measure the data. RESULTS: The correlation coefficient data analysis resulted in intraclass correlation coefficients of 0.94 (standard error of measurement 0.35) in supine lying, 0.88 (0.66) in standing and 0.88 (0.56) in walking. CONCLUSION: The method described is a reliable tool for measuring changes in thickness of transversus abdominis in supine lying, standing and walking. RELEVANCE: This procedure has the potential to detect dysfunctional changes in abdominal muscle activity for patients with low back pain in a functional setting.

Abdominal Muscles↗
PubMed1984

Influence of globus pallidus on arm movements in monkeys. I. Effects of kainic acid-induced lesions.

The role of basal ganglia output via the globus pallidus (GP) was examined in monkeys trained to make rapid arm-reaching movements to a visual target in a reaction-time task. When neurons in the globus pallidus were destroyed by injection of kainic acid (KA) during task execution, contralateral arm movement times (MT) were increased significantly, with little or no change in reaction times (RT). The slowed movements were associated with a generalized depression in the amplitude and rate of rise of electromyographic (EMG) activity in all the contralateral muscles studied at the wrist, elbow, shoulder, and back, but there was no change in the sequential activation of these muscles. The most profound and persistent increases in movement time occurred when neurons were destroyed in the ventrolateral and caudal aspects of the internal as well as external pallidal segment. These results suggest a role for globus pallidus output in scaling the magnitude and/or buildup of EMG activity without affecting the initiation or the sequential organization of the programmed motor output.

Animals↗
PubMed1978

Reconditioning aging muscles.

Weakness or stiffness of key posture muscles can cause much of the disability seen in elderly patients. Too much tension and too little exercise greatly increase the natural loss of muscular fitness with age. A systematic program of exercise, stressing relaxation and stretching of tight muscles and strenghthening of weak muscles, can improve physical fitness. The program must be tailored to the patient, starting with relaxation and gentle limbering exercises and proceeding ultimately to vigorous muscle-stretching exercises. Muscle aches and pain from tension and muscle imbalance are to be expected. Relaxation relieves tension pain, and strengthening weak muscles and stretching tight muscles will correct muscle imbalance. To prevent acute muscle spasm, the patient should avoid excessive exertion and increase exercise intensity gradually.

Aged↗
PubMed1989

[Training of patients with urinary incontinence].

The different types of urinary incontinence are defined and the possible educational treatment modalities are described. Stress incontinence may be treated by pelvic floor exercise and bio-feed-back. The object is training in muscle awareness with the purpose of teaching the patients to squeeze without activating the abdominal muscles. Significant improvement can be obtained in 22-63% of the patients. Urge incontinence can be treated by bladder drill and bio-feed-back. Voluntary control over the detrusor reflex is re-educated and the patients are instructed to adhere to a fixed voiding schedule every three hours. In women, 80% may be improved. In reflex incontinence, prophylactic bladder emptying may be initiated by stimulation of specific trigger points. Overflow incontinence may be reduced by optimal voiding technique and clean intermittent self-catheterization. Postmicturition dribble can be relieved by manual emptying of the urethra. No treatment is known for giggle incontinence. In nocturnal enuresis, conditioning treatment is recommended. Immediate waking is essential. Environmental incontinence is treated by securing easy access to voiding facilities and by training in toileting skills. Half of the patients are curable.

Female↗
PubMed2006

[Rhabdomyolysis accompanying low back pain following prolonged urological surgery in the exaggerated lithotomy position: a case report].

A 69-year-old man (163 cm, 72 kg) with hypertension and lumbar spondylosis deformans was diagnosed as having prostate cancer and subsequently underwent perineal prostatectomy under sevoflurane anesthesia combined with epidural anesthesia using mepivacaine in the exaggerated lithotomy position. Supplemental intravenous fentanyl was also given. The patient's systolic blood pressure ranged between 80 and 120 mmHg throughout the 255-minute procedure. On emergence from the anesthesia, the patient was free from pain and epidural infusion with 0.2% ropivacaine, fentanyl 2 microg x ml(-1) and droperidol 12.5 microg x ml(-1) at a rate of 5 ml x hr(-1) was started. Shortly thereafter, the patient began to complain of severe low back pain, which required intramuscular pentazocine injection as a rescue analgesic for 5 days postoperatively. On the 6th postoperative day, creatine kinase, which had apparently passed its peak, was 4,795 IU x l(-1). MRI on the 8th day demonstrated the presence of hemorrhage in the bilateral erector spinae muscles. On day 16, CT scan also confirmed partial necrotizing changes in the bilateral gluteal and erector spinae muscles. We believe that the low back pain was due to rhabdomyolysis secondary to ischemia of the lumbar and pelvic muscles resulting from lengthy compression during surgery. The recognition and early diagnosis of rhabdomyolysis following prolonged time in the exaggerated lithotomy position are the key to prevent potentially fatal sequelae.

Aged↗
PubMed1988

Postural modifications of VDU operators wearing bifocal spectacles.

This paper describes the postural changes experienced by presbyopic operators of VDU workstations while wearing a pair of bifocal spectacles. All operators reported in this paper had suffered neck and back aches, in addition to generalised problems of asthenopia, while using the VDU workstation. The ages of the operators ranged between 47 and 58 years. The operators' head movements, in looking from the keyboard to the screen, were two to three times greater when bifocal spectacles were worn compared with specially prescribed single-vision occupational spectacles. There were also greater movements in the flexion of the wrist and elbow while using bifocal spectacles and looking from the keyboard to the screen. There was no relationship between the amount of head movement and the position of the bifocal reading segment with respect to the operators' pupil. It was concluded that the symptoms reported by these presbyopic operators were due to static loading of the muscles in the neck and back, induced by the use of bifocal spectacles.

Journal Article↗
PubMed1996

Evaluating the child with back pain.

The most common causes of serious low back pain in children include spondylolysis, Scheuermann disease and musculoligamentous injury. Questions should be asked about the mechanism of onset and exacerbating factors, and the frequency, duration and severity of the pain. The examination should check gait and alignment, flexibility, strength and reflexes, and localize and evaluate the pain. Warning signs of serious problems include constant pain in a child younger than 11 years of age that lasts for several weeks or occurs spontaneously at night, repeatedly interferes with school, play or sports, or is associated with marked stiffness and limitation of motion, fever or neurologic abnormalities. Pain at the lumbosacral junction may suggest spondylolysis or spondylolisthesis. Scheuermann disease is diagnosed by the observance of wedging, irregularity or growth disturbance of three successive vertebrae. Musculoligamentous pain may result from injury to or overuse of muscles or joints of the back. Rare causes include discitis, tuberculosis, bone or spinal cord tumor, pyelonephritis and retroperitoneal infection.

Algorithms↗
PubMed2002

Maximal subtotal extirpation of the horizontal rectus extraocular muscles for the treatment of nystagmus with no null point. A report of four successful human cases.

PURPOSE: To evaluate the visual and restoration of normal appearance results of maximal excision of the horizontal rectus muscles in nystagmus patients. SETTING: Menelik II Hospital, Addis Ababa, Ethiopia and the Sinskey Eye Institute, Santa Monica, California. METHODS: The medial and lateral rectus muscles were extirpated as far back as possible with an enucleation snare in four patients with horizontal nystagmus. A complete eye examination was performed pre- and postoperatively. Using a camcorder, ocular movements were recorded before surgery, and at postop; days 1 and 40, and months 1, 3 and 10. RESULTS: All four patients had a marked reduction in both abnormal and normal horizontal eye movement, and improvement in objective visual acuity. Postoperative residual intermittent fine horizontal movement was recorded in the left eye in a 6 year old and in both eyes of a 41 year old patient. A residual rotary component was recorded in a 15 year-old patient. The 6 and 9 year-old patients each developed a moderate exotropia. The 15 and 41 year-old patients maintained binocular fusion with some residual ability to converge. Vision increased subjectively in all cases. CONCLUSION: Subtotal myectomy of the horizontal muscles in horizontal nystagmus with no null point was very effective in improving and/or eliminating horizontal eye movement. Restoration of normal or near normal appearance and improvement in visual acuity occurred in all cases. None of the patients complained of their loss of horizontal gaze and eye movement. More complete myectomy of the muscles should produce total elimination of both normal and abnormal horizontal eye movement including nystagmus.

Adolescent↗
PubMed1996

Isokinetic performance capacity of trunk muscles. Part II: Coefficient of variation in isokinetic measurement in maximal effort and in submaximal effort.

It has been claimed that with the aid of isokinetic trunk strength measuring devices it is possible to distinguish true muscular weakness from submaximal effort in the test. This proposition is based on the presumption that in the isokinetic trunk strength test identical performances can only be reproduced by maximal effort. The purpose of this study was to investigate whether it is possible to distinguish maximal effort from submaximal with the aid of the coefficient of variation (CV) in an isokinetic trunk muscle strength test. The study group included 35 (21 male and 14 female) subjects of whom 12 were healthy, 10 had a mild low-back pain and 13 had a more severe chronic low-back pain. The subjects performed five consecutive bendings both with maximal (100%) and submaximal (50%) efforts at a speed of 90 degrees/second. In maximal effort only healthy subjects reached an average level of CV close to 10% both in extension and in flexion. In the chronic low-back pain group the average CV was close to 20%. The difference in CV was statistically significant (p < 0.05-0.02) between the healthy and the chronic low-back pain subjects. In the submaximal effort all health groups had a CV of approximately 20% or more and no significant differences were found. The group of slightly variable measurements (CV = 11-20%) was remarkably large in both the maximal and submaximal effort. The results suggest that an effort with a CV of 11-20% cannot be classified as definitely submaximal or maximal. When the CV is less than 10% the effort can be fairly certainly classified as maximal.

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