Muscle imbalance in hallux valgus: an electromyographic study

OBJECTIVE: Hallux valgus is a very common foot deformity in modern societies. Muscle imbalance in abductor and adductor muscles was cited as a major factor in the production of hallux valgus. Our aim in this study was to evaluate the role of certain muscles in this deformity. DESIGN: Twenty hallux valgus patients and 20 healthy volunteers participated in the study. After thorough physical, neurologic, and radiographic investigations, we performed an electromyographic study to observe the relationship of hallux valgus deformity with the muscles coordinating first metatarsophalangeal joint movements. Voluntary extension, flexion, abduction, and adduction at the hallux with maximum resistance were performed. Firing rates and amplitudes of motor unit potentials of four muscles: musculus abductor hallucis, musculus adductor hallucis, musculus extensor hallucis longus, and musculus flexor hallucis brevis were recorded. Statistical analysis, including Spearman's correlation analysis and Mann-Whitney U tests were performed with SPSS 8.0 for Windows. RESULTS: We observed that in the hallux valgus group, abduction activity of musculus abductor hallucis was markedly decreased when compared with adduction of musculus adductor hallucis. Motor unit potential amplitude of abductor activity recorded from musculus abductor hallucis was slightly more than half of the activity in flexion. CONCLUSION: Muscle imbalance in abductor and adductor muscles is apparent in hallux valgus deformity, and this imbalance may be the reason or the result of joint deformity.     

Idiopathic scoliosis in identical (monozygotic) twins

The exact nature of the primary predisposing cause of idiopathic scoliosis is unknown. Hereditary and/or environmental factors may be responsible. Two sets of identical twins presenting in adolescence with concordant scoliotic curves were studied and lend support for a hereditary predisposition favoring a multifactorial inheritance.     

Motor innervation of the flexor pollicis brevis: an electromyographic study.

Percutaneous stimulation of the ulnar and median nerves at the wrist, with simultaneous recording of action potentials on a standard electromyograph oscilloscope, was performed to observe the motor innervation of the flexor pollicis brevis muscle. Both the deep and the superficial heads of the muscle were studied in twenty-three subjects. Results showed that the most common pattern of innervation was exclusive ulnar nerve supply in both heads, with 52.4 percent of the subjects showing this pattern. Dual supply by both median and ulnar nerves occurred next in frequency with 19.0 percent showing this pattern in both heads of the muscle. Exclusive median nerve supply was observed in only 9.5 percent of the total cases studied. The remaining 19 percent showed varying patterns, with each head of the muscle supplied differently. If no differentiation between deep and superficial heads is made, this 19 percent may be considered as dual innervation of the muscle. In this case, it may be concluded that 38 percent of the muscles studied showed some type of dual innervation.     

Case study involving suctioning of an electromyographic endotracheal tube

The electromyographic endotracheal tube (EMG-ETT) is a relatively new tool used to measure integrity of the vocal cord structures during surgery. We describe a case in which an EMG-ETT was inserted for the operative period but not replaced with an ETT during the immediate postoperative period. Intensive care unit nurses had difficulty suctioning the EMG-ETT. The patient was not provided the pulmonary toilet necessary until the EMG-ETT was removed and replaced with a regular ETT. The purpose of this article is to make anesthesia providers aware that when mechanical ventilation is required during the postoperative period, the EMG-ETT should be removed and replaced with a regular ETT to facilitate pulmonary toilet.     

Neck flexor muscle fatigue in adolescents with headache: an electromyographic study.

BACKGROUND: Muscular disorders of the neck region may be of importance for the etiology of tension-type headache. However, in adolescents, there are no data on the association between neck muscle fatigue and headache. AIM: To study differences in fatigue characteristics of the neck flexor muscles in adolescents with and without headache. METHODS: A population-based sample of 17-year-old adolescents with migraine-type headache (N=30), tension-type headache (N=29) and healthy controls without headache (N=30) was examined. Surface EMG data were recorded from the sternocleidomastoid (SCM) muscles bilaterally during an isometric neck flexor endurance test. The spectral median frequency (MF) change during the total endurance time (TMF) and the initial time of 30s (IMF) was calculated. The intensity of discomfort in the neck area was assessed with the visual analogue scale (VAS). RESULTS: The rate of decline in TMF of both SCM muscles was significantly increased in the tension-type headache group compared with controls (right SCM, P=0.030, OR 2.0, 95% 1.2-3.7; left SCM, P=0.009, OR 2.5, 95% 1.4-4.9), while no significant differences were found between controls and subjects with migraine. The rate of decline in IMF, the total endurance time (P=0.050), and VAS did not differ significantly among the study groups. CONCLUSIONS: This preliminary finding shows that increased neck flexor muscle fatigue in adolescents seems to be associated with tension-type headache.     

健康教育光盘在支具治疗青少年特发性脊柱侧弯的应用研究

目的探讨应用健康教育光盘在支具治疗青少年特发性脊柱侧弯中的应用效果。方法将制作健康教育光盘前后来我科进行支具治疗的脊柱侧弯患者分成两组：实验组44例,对照组48例。实验组给予观看健康教育光盘及文字资料,并辅以口头讲解及实践指导。对照组给予阅读文字资料及口头宣教。结果实验组患者的疾病相关知识知晓率、功能锻炼的正确掌握率及依从性均高于对照组（P〈0．05）。实验组44例患者中,有42例患者脊柱畸形外观及cobb’s角均有改善,总有效率为95．5％。结论应用健康教育光盘对支具治疗青少年特发性脊柱侧弯患者及家长进行健康教育,能明显提高健康教育效果和质量,从而提高佩戴支具的疗效。     

Shoulder muscle recruitment patterns during commonly used rotator cuff exercises: an electromyographic study

BACKGROUND AND PURPOSE: Graduated rotation exercises performed with the arm by the side are commonly used to improve rotator cuff (RC) muscle function. The aim of this study was to compare the pattern of recruitment of the RC muscles with that of other shoulder muscles that rotate the shoulder joint during these exercises. SUBJECTS: The nondominant shoulders of 15 subjects who were healthy were tested. METHODS: Activity in the infraspinatus, supraspinatus, subscapularis, latissimus dorsi, pectoralis major, and posterior deltoid muscles was recorded. Low-, medium-, and high-intensity rotation exercises were performed with a pulley system. RESULTS: As the intensity of both internal and external rotation exercises increased, activity increased in a systematic manner in all muscles capable of producing rotation torque during concentric and eccentric contractions. DISCUSSION AND CONCLUSION: The results indicate that, in people who are healthy, the motor strategy used to deal with increasing rotation resistance with the arm in a pendant position is to gradually increase activity in all shoulder rotation torque-generating muscles.     

Identifying lumbosacral radiculopathies: an optimal electromyographic screen

OBJECTIVE: The objective of this study was to determine prospectively the optimal electromyographic screening examination of the lower limb that ensures identification of those lumbosacral radiculopathies that can be electrodiagnostically confirmed, yet minimizes the number of muscles studied. DESIGN: A prospective multicenter study was conducted from May 1996 to September 1997. Patients with suspected lumbosacral radiculopathy referred to participating electrodiagnostic laboratories were recruited and examined by needle electromyography using a standard set of muscles. Patients with electrodiagnostically confirmed lumbosacral radiculopathies were selected for analysis. Various muscle screens were tested against this group of patients with radiculopathies to determine the frequency with which each screen identified the patient with radiculopathy. RESULTS: There were 102 patients identified. When paraspinal muscles were one of the screening muscles, four-muscle screens identified 88-97% of the radiculopathies, five-muscle screens identified 94-98%, and six-muscle screens 98-100%. When paraspinal muscles were not part of the screen, identification rates were lower for all screens, and eight distal muscles were necessary to identify about 90% of the radiculopathies. CONCLUSIONS: Six-muscle screens with paraspinal muscles yielded consistently high identification rates. Studying additional muscles produced no improvements in identification.     

Idiopathic pulmonary fibrosis: an update

Idiopathic pulmonary fibrosis (IPF) is a chronic lung condition of uncertain aetiology that should be considered in the differential diagnosis of patients who experience breathlessness, cough and reduced exercise tolerance. IPF is characterized histologically by the presence of usual interstitial pneumonia, and often has typical radiological appearances. Long-term successful management options are limited and frequently unsuccessful; as the disease progresses, palliation of symptoms becomes the mainstay of treatment. In a minority of patients, lung transplantation provides the only hope of long-term survival. The median survival of patients with IPF is approximately 3 years, which in turn emphasizes the need for further investigation into its pathogenesis and potential disease-modifying pharmacological therapies.     

Reaction time and movement time in patients with carpal tunnel syndrome: an electromyographic study

OBJECTIVE: To measure the motor performance of the flexor pollicis brevis, first dorsal interosseus, and flexor pollicis longus muscles using the parameters electromyographic muscle reaction time and movement time in patients with carpal tunnel syndrome during key turning function. METHOD: A total of 37 female patients with right hand pain were divided into two groups: 21 with an electrophysiologically confirmed diagnosis of carpal tunnel syndrome (Group I), and 16 with normal electrophysiological findings (Group II). The reaction time and movement time values obtained by surface electromyography of the right flexor pollicis brevis, first dorsal interosseus, and flexor pollicis longus muscles were compared between groups. RESULTS: Of the 21 patients in Group I, 15 had mild, four moderate, and two severe median nerve lesions. No significant difference between groups was found in the electromyographic reaction time and movement time values of the right flexor pollicis brevis, first dorsal interosseus, and flexor pollicis longus muscles during key turning (P>0.05). There was also no significant difference in electromyographic reaction time and movement time between six patients with severe or moderate carpal tunnel syndrome and 15 patients with mild carpal tunnel syndrome in Group I (P>0.05). Sixteen patients in Group II did not have carpal tunnel syndrome. CONCLUSION:The results indicate that patients with and without carpal tunnel syndrome have similar values of reaction time and movement time of the flexor pollicis brevis, first dorsal interosseus, and flexor pollicis longus muscles during the pinch grasp function of the hand. RELEVANCE: Muscle reaction time and movement time, and hence the motor performance in electrophysiologically confirmed carpal tunnel syndrome patients appear to have similar parameters in patients with hand pain whose diagnosis were not confirmed with electrophysiologically.     

Idiopathic scoliosis: correction of lateral and rotational deformities using the Cotrel-Dubousset spinal instrumentation system

The Cotrel-Dubousset instrumentation (CDI) system developed between 1982 and 1984 is now being used extensively for the posterior correction of idiopathic scoliosis. In this study we compared the lateral and rotational correction obtained with CDI to that obtained with Harrington rod instrumentation and Drummond wiring. We matched 14 patients who had had CDI by age and sex with 14 patients who had had either Harrington rod instrumentation (n = 5) or Drummond wiring (n = 9). Average lateral curve correction was significantly better with CDI than with the combination of the other systems (71.9% and 56.4%, respectively; P less than .01). Average rotational correction was studied using the methods of Mehta, and Nash and Moe; all patients having CDI showed a median rotational improvement of 30 degrees; 57% of the comparison group had minimal improvement (P less than .01). These results suggest that CDI may offer a significant alternative to the Harrington and Drummond spinal instrumentation systems in the surgical management of adolescent idiopathic scoliosis.     

Idiopathic scoliosis. Gas exchange and the age dependence of arterial blood gases.

The aims were to examine the gas exchange and arterial blood gas abnormalities among patients with scoliosis, and the correlation of these abnormalities with age and severity of deformity. Means among 51 patients were as follows: age 25.4 +/- 17.5 yr, angle of scoliosis 80.2 +/- 29.9 (SD), vital capacity 1.94 +/- 0.91 (SD) (i.e. 60.6 +/- 19.2% of predicted), PaO2 85.8 +/- 12.0 (SD), PaCO2 42.4 +/- 8.0, physiological dead space to tidal volume ratio 0.438 +/- 0.074 (SD), and alveolar-arterial oxygen difference breathing air 14.9 +/- 8.9 (SD). Statistically significant correlations were as follows: the PaCO2 and physiological dead space to tidal volume ratio increased with age, and the PaO2 and alveolar ventilation decreased with age. The PaO2, alveolar ventilation, and tidal volume were inversely related to the angle of scoliosis and directly related to the vital capacity, precent predicted vital capacity, and the compliance of the respiratory system. The physiological dead space to tidal volume ratio and the alveolar-arterial oxygen difference were inversely related to the vital capacity, percent predicted vital capacity, and the compliance of the respiratory system. PaCO2 was directly related to the elastance of the respiratory system. We conclude that ventilation-blood flow maldistribution as a result of deformity of the rib cage was the primary abnormality in gas exchange, and that with age there was progressive deterioration in gas exchange. The age-dependent increase in PaCO2 and decrease in alveolar ventilation were due to the increasing physiological dead space to tidal volume ratio and failure of a compensatory increase in ventilation.