Turning away from whiplash. An EMG study of head rotation in whiplash impact.

OBJECTIVE: To determine the response of the cervical muscles to whiplash-type perturbations through low-velocity frontal impacts when the head is rotated to the right and left. METHODS: Twenty healthy volunteers were subjected to increasing acceleration in low-velocity frontal impacts, randomly with head rotated either left or right. Bilateral EMG of the sternocleidomastoids, trapezii, and splenii capitis and acceleration of the sled, torso, and head were recorded. RESULTS: With either direction of head rotation at the time of impact, the muscle responses increased with increasing levels of acceleration (p < 0.01). The time to onset and peak electromyogram for all muscles progressively decreased with increasing levels of acceleration. With the head rotated to the left, the left trapezius generated 77% of its maximal voluntary contraction (MVC) EMG (more than double the response of other muscles). In comparison, the right trapezius generated only 33% of its MVC. The right sternocleidomastoid (25%) and left splenius muscles (32%), the ones responsible for head rotation to the left, were more active than their counterparts (the left sternocleidomastoid generated only 5% of its MVC EMG and the right splenius 9%). On the other hand, with the head rotated to the right, the right trapezius generated 71% of its MVC EMG, while the left trapezius generated only 30% of this value. Again, the left sternocleidomastoid (27% of its MVC EMG) and right splenius (28% of its MVC EMG), being responsible for head rotation to the right, were more active than their counterparts (the right sternocleidomastoid generated only 4% of its MVC EMG and the left splenius 13%). CONCLUSIONS: Frontal impacts tend to generate the most muscle activity in the ipsilateral trapezius muscle, increasing the risk of their injury.     

Cervical muscle response to whiplash-type right anterolateral impacts

Frontal impacts are a common cause of whiplash injury. Yet, volunteer studies of the cervical muscular response and head–neck kinematics to frontal impacts are uncommon, and specifically, the effect of an offset (anterolateral) frontal impact on the resultant muscle responses is unknown. The purpose of this study was to determine the response of the cervical muscles to increasing low-velocity frontal impacts offset by 45° to the right, and to compare the quantitative effects of expected and unexpected impact. Ten healthy volunteers were subjected to frontal impacts, offset by 45° to the subjects right, of 5.1-, 8.7-, 12-, and 13.7-m/s² peak acceleration at two levels of expectation: expected and unexpected. Bilateral electromyograms of the sternocleidomastoids, trapezii, and splenii capitis were recorded. Triaxial accelerometers recorded the acceleration of the chair, torso at the shoulder level, and head of the participant. At a peak acceleration of 13.7 m/s², with an unexpected impact, the contralateral trapezius (i.e., left trapezius in a right anterolateral impact) generated 83% of its maximal voluntary contraction electromyogram, whereas all other muscles generated 50% or less of this variable. Although it generated less EMG, the splenius capitis muscle also tended to show an asymmetric EMG response, with the left (contralateral) splenius capitis generating a higher percentage (46%) of its maximal voluntary contraction electromyogram than the ipsilateral (right) splenius capitis. In comparison, the sternocleidomastoid muscles behaved symmetrically and generated 25% or less of this variable under all impact conditions. Similarly, the times to onset and times to peak electromyogram for the contralateral (left) splenius capitis and (left) trapezius progressively decreased with increasing levels of acceleration (p<0.01). Subjects exhibited lower levels of their maximal voluntary contraction electromyogram when the impact was expected (p<0.01). The kinetic variables and the electromyographic variables regressed significantly on the acceleration (p<0.01). In response to right anterolateral impacts, muscle responses were greater with higher levels of acceleration, and more specifically, when a frontal impact is offset to the subjects right, it results in not only increased EMG generation in the contralateral trapezius, but the splenius capitis contralateral to the direction of impact also bears part of the force of the neck pertubation. Expecting or being aware of imminent impact plays a role in reducing muscle responses in low-velocity anterolateral impacts.     

Number and cost of claims linked to minor cervical trauma in Europe: results from the comparative study by CEA,AREDOC and CEREDOC

Comparative epidemiological study of minor cervical spine trauma (frequently referred to as whiplash injury) based on data from the Comité Européen des Assurances (CEA) gathered in ten European countries. To determine the incidence and expenditure (e.g., for assessment, treatment or claims) for minor cervical spine injury in the participating countries. Controversy still surrounds the basis on which symptoms following minor cervical spine trauma may develop. In particular, there is considerable disagreement with regard to a possible contribution of psychosocial factors in determining outcome. The role of compensation is also a source of constant debate. The method followed here is the comparison of the data from different areas of interest (e.g., incidence of minor cervical spine trauma, percentage of minor cervical spine trauma in relationship to the incidence of bodily trauma, costs for assessment or claims) from ten European countries. Considerable differences exist regarding the incidence of minor cervical spine trauma and related costs in participating countries. France and Finland have the lowest and Great Britain the highest incidence of minor cervical spine trauma. The number of claims following minor cervical spine trauma in Switzerland is around the European average; however, Switzerland has the highest expenditure per claim at an average cost of €35,000.00 compared to the European average of €9,000.00. Furthermore, the mandatory accident insurance statistics in Switzerland show very large differences between German-speaking and French- or Italian-speaking parts of the country. In the latter the costs for minor cervical spine trauma expanded more than doubled in the period from 1990 to 2002, whereas in the German-speaking part they rose by a factor of five. All the countries participating in the study have a high standard of medical care. The differences in claims frequency and costs must therefore reflect a social phenomenon based on the different cultural attitudes and medical approach to the problem including diagnosis. In Switzerland, therefore, new ways must be found to try to resolve the problem. The claims treatment model known as “Case Management” represents a new approach in which accelerated social and professional reintegration of the injured party is attempted. The CEA study emphasizes the fundamental role of medicine in that it postulates a clear division between the role of the attending physician and the medical expert. It also draws attention to the need to train medical professionals in the insurance business to the extent that they can interact adequately with insurance professionals. The results of this study indicate that the usefulness of the criterion of so-called typical clinical symptoms, which is at present applied by the courts to determine natural causality and has long been under debate, is inappropriate and should be replaced by objective assessment (e.g. accident and biomechanical analysis). In addition, the legal concept of adequate causality should be interpreted in the same way in both third party liability and social security law, which is currently not the case.     

颈部肌力和软组织刚度测试的研究进展

颈部肌肉的生物力学评价对颈椎病的诊疗有着重要意义,颈部肌力和软组织刚度测试是颈部肌肉生物力学测试的两个方面。等长肌力测试操作相对简单、成本较低,能对3级以下的肌力进行评价,而等速肌力测试可评定关节活动在任意位置上的肌力情况。利用载荷-位移曲线评价局部软组织刚度时不能区分不同组织间的刚度差别,而弹性成像技术不仅能够利用图像显示不同组织的弹性差异,还可以对皮下组织和肌肉的弹性模量分别进行量化分析,但很难通过分析颈部整体的刚度来观察颈椎柔韧性的不同。总之,多种测试方法的联合运用不仅有助于颈部肌肉的生物力学评价,而且有助于有效的颈部肌肉的生物力学数学模型的建立。另外,等速肌力测试和弹性成像技术更好地应用到颈部肌肉的生物力学测试上还有待进一步验证和优化。     

颈前路椎间盘切除植骨融合内固定术治疗颈椎管狭窄患者颈椎挥鞭样损伤的疗效评价

【摘要】 目的: 探讨颈前路椎间盘切除植骨融合内固定术治疗因颈椎间盘突出致颈椎管狭窄患者遭受颈椎挥鞭样损伤的临床疗效。方法：回顾性分析2010年1月~2018年12月在我院行颈前路颈椎间盘切除植骨融合内固定术的50例颈椎挥鞭样损伤患者的临床资料,其中男32例,女18例,年龄35~75岁（53.6±13.6岁）。根据术前颈椎MRI T2加权相中矢状位上目标节段纤维性椎管最小矢状径分为狭窄组（最小矢状径≤13mm,32例）和非狭窄组（最小矢状径＞13mm,18例）,两组间年龄及性别无统计学差异。狭窄组随访25.6±7.4个月,非狭窄组27.4±8.3个月,两组随访时间差异无统计学意义。记录两组患者术前及术后1个月、1年及末次随访时ASIA评分的总分、感觉评分、运动评分,计算术后1个月、1年及末次随访时的日本骨科协会（Japanese Orthopedic Association,JOA）评分改善率和末次随访时的手术改善率,记录相关并发症的发生情况。结果：ASIA评分总分,每组术后各时间点与术前比较均有显著性增加（P＜0.05）;术前和术后1个月时两组间差异均无统计学意义,但术后1年及末次随访时差异均有统计学意义（P＜0.05）。ASIA上肢运动评分,每组术后各时间点与术前比较均有显著性增加（P＜0.05）,术前及术后各时间点两组间比较差异均有统计学意义（P＜0.05）。ASIA下肢运动评分,每组术后各时间点与术前比较均有显著性增加（P＜0.05）,术前及术后各时间点两组间比较差异无统计学意义（P＞0.05）。ASIA感觉评分,每组术后各时间点与术前比较均有显著性增加（P＜0.05）;术前两组间差异无统计学意义（P＞0.05）,术后各时间点两组间比较差异有统计学意义（P＜0.05）。每组患者术后各时间点JOA评分与术前相比均明显改善（P＜0.05）。术后1个月狭窄组与非狭窄组JOA评分改善率分别为37.3%和55.9%,术后1年分别为61.3%和73.6%,末次随访分别为77.3%和91.1%,上述各时间点两组间比较差异有统计学意义（P＜0.05）。末次随访时,狭窄组手术改善率为88%（28/32）,非狭窄组为（94%）（17/18）,差异有统计学意义（P＜0.05）。两组术后各出现4例颈部轴性疼痛;狭窄组13例、非狭窄组11例术后出现吞咽疼痛或吞咽异物感,行对症治疗后改善;狭窄组出现1例椎前血肿和2例C5神经根麻痹,经神经营养、消肿等对症治疗后好转。随访期间,两组患者均未发生内固定松动或摔倒等意外突发事件。结论:颈前路椎间盘切除植骨融合内固定术治疗颈椎挥鞭样损伤患者能够获得满意的疗效,但外伤前合并有颈椎间盘突出致颈椎管狭窄的患者术后短期疗效相对较差。     

Surgical anatomy of the cervical sympathetic trunk during anterolateral approach to cervical spine

The sympathetic trunk is sometimes damaged during the anterior and anterolateral approach to the cervical spine, resulting in Horner’s syndrome. No quantitative regional anatomy in fresh human cadavers describing the course and location of the cervical sympathetic trunk (CST) and its relation to the longus colli muscle (LCM) is available in the literature. The aims of this study are to clearly delineate the surgical anatomy and the anatomical variations of CST with respect to the structures around it and to develop a safer surgical method that will diminish the potential risk of CST injury. In this study, 30 cadavers from the Department of Forensic Medicine were dissected to observe the surgical anatomy of the CST. The cadavers used in this study were fresh cadavers chosen at 12–24 h postmortem. The levels of superior and intermediate ganglions of cervical sympathetic chain were determined. The distance of the sympathetic trunk from the medial border of LCM at C6, the diameter of the CST at C6 and the length and width of the superior and intermediate (middle) cervical ganglion were measured. Cervical sympathetic chain is located posteromedial to carotid sheath and just anterior to the longus muscles. It extends longitudinally from the longus capitis to the longus colli over the muscles and under the prevertebral fascia. The average distance between the CST and medial border of the LCM at C6 is 11.6 ± 1.6 mm. The average diameter of the CST at C6 is 3.3 ± 0.6 mm. Superior ganglion of CSC in all dissections was located at the level of C4 vertebra. The length and width of the superior cervical ganglion were 12.5 ± 1.5 and 5.3 ± 0.6 mm, respectively. The location of the intermediate (middle) ganglion of CST showed some variations. The length and width of the middle cervical ganglion were 10.5 ± 1.3 and 6.3 ± 0.6 mm, respectively. The CST’s are at high risk when the LC muscle is cut transversely, or when dissection of the prevertebral fascia is performed. Awareness of the CST’s regional anatomy may help the surgeon to identify and preserve it during anterior cervical surgeries.     

下颈椎屈伸运动对椎间孔面积影响的实验研究

目的：定量描述下颈椎屈伸运动时椎间孔面积变化。方法：对５具正常成人男性新鲜颈椎标本行动态Ｘ线４５°斜位摄片，图象分析计算椎间孔面积。结果：屈曲时颈椎间孔面积增大，伸展时缩小。其中Ｃ３～４，Ｃ４～５变化最大。Ｃ３～４节段椎间孔面积与椎间角度呈直线关系，也可拟合为Ｌｏｇｉｓｔｉｃ曲线。结论：屈曲时椎间孔面积增大对颈椎病变神经根刺激症状的诊断和治疗具有相应临床意义     

The clinical presentation of chronic whiplash and the relationship to findings of MRI fatty infiltrates in the cervical extensor musculature: a preliminary investigation

The objective was to determine whether any measurable changes in sensory responses, kinesthetic sense, cervical motion, and psychological features were related to established fatty infiltration values in the cervical extensor musculature in subjects with persistent whiplash. It is unknown if fatty infiltrate is related to any signs or symptoms. Data on motor function, Quantitative Sensory Testing, psychological and general well-being, and pain and disability were collected from 79 female subjects with chronic whiplash. Total fat values were created for all subjects by averaging the muscle fat indices by muscle, level, and side from our MRI dataset of all the cervical extensor muscles. Results of this study indicate the presence of altered physical, kinesthetic, sensory, and psychological features in this cohort of patients with chronic whiplash. Combined factors of sensory, physical, kinesthetic, and psychological features all contributed to a small extent in explaining the varying levels of fatty infiltrate, with cold pain thresholds having the most influence (r ² = 0.28; P = 0.02). Identifying and relating quantifiable muscular alterations to clinical measures in the chronic state, underpin some clinical hypotheses for possible pathophysiological processes in this group with a chronic and recalcitrant whiplash disorder. Future research investigations aimed at accurate identification, sub-classification, prediction, and management of patients with acute and chronic whiplash is warranted and underway.     

家兔颈椎两侧肌肉平衡失调对椎动脉血流的影响

目的 探讨颈椎两侧肌肉平衡失调对椎动脉血流的影响。方法 通过外载荷力的作用，制作家兔椎动脉型颈椎病的动物模型，测定颈椎两侧肌肉张力，并记录各组动物椎动脉血流量的变化。结果 模型组受牵拉侧斜方肌、提肩胛肌、横突间肌等肌肉的肌张力明显高于对侧及正常组，模型组受牵拉侧椎动脉血流量明显低于对侧及正常组。结论 颈椎两侧肌肉平衡状态失调可使受牵拉侧颈部肌肉痉挛，椎动脉血流量明显下降，成功建立了椎动脉颈椎病模型。     

Neurophysiological and biomechanical characterization of goat cervical facet joint capsules.

Cervical facet joints have been implicated as a major source of pain after whiplash injury. We sought to identify facet joint capsule receptors in the cervical spine and quantify their responses to capsular deformation. The response of mechanosensitive afferents in C5-C6 facet joint capsules to craniocaudal stretch (0.5 mm/s) was examined in anaesthetized adult goats. Capsular afferents were characterized into Group III and IV based on their conduction velocity. Two-dimensional strains across the capsules during stretch were obtained by a stereoimaging technique and finite element modeling. 17 (53%) Group III and 14 (56%) Group IV afferents were identified with low strain thresholds of 0.107+/-0.033 and 0.100+/-0.046. A subpopulation of low-strain-threshold afferents had discharge rate saturation at the strains of 0.388+/-0.121 (n=9, Group III) and 0.341+/-0.159 (n=9, Group IV). Two (8%) Group IV units responded only to high strains (0.460+/-0.170). 15 (47%) Group III and 9 (36%) Group IV units could not be excited even by noxious capsular stretch. Simple linear regressions were conducted with capsular load and principal strain as independent variables and neural response of low-strain-threshold afferents as the dependent variable. Correlation coefficients (R2) were 0.73+/-0.11 with load, and 0.82+/-0.12 with principal strain. The stiffness of the C5-C6 capsules was 16.8+/-11.4 N/mm. Our results indicate that sensory receptors in cervical facet joint capsules are not only capable of signaling a graded physiological mechanical stimulus, but may also elicit pain sensation under excessive deformation.     

Effect of whole-body vibration on lower-limb EMG activity in subjects with and without spinal cord injury

Objective

Traumatic spinal cord injury (SCI) results in substantial reductions in lower extremity muscle mass and bone mineral density below the level of the lesion. Whole-body vibration (WBV) has been proposed as a means of counteracting or treating musculoskeletal degradation after chronic motor complete SCI. To ascertain how WBV might be used to augment muscle and bone mass, we investigated whether WBV could evoke lower extremity electromyography (EMG) activity in able-bodied individuals and individuals with SCI, and which vibration parameters produced the largest magnitude of effect.

Methods

Ten male subjects participated in the study, six able-bodied and four with chronic SCI. Two different manufacturers'' vibration platforms (WAVE^® and Juvent™) were evaluated. The effects of vibration amplitude (0.2, 0.6 or 1.2 mm), vibration frequency (25, 35, or 45 Hz), and subject posture (knee angle of 140°, 160°, or 180°) on lower extremity EMG activation were determined (not all combinations of parameters were possible on both platforms). A novel signal processing technique was proposed to estimate the power of the EMG waveform while minimizing interference and artifacts from the plate vibration.

Results

WBV can elicit EMG activity among subjects with chronic SCI, if appropriate vibration parameters are employed. The amplitude of vibration had the greatest influence on EMG activation, while the frequency of vibration had lesser but statistically significant impact on the measured lower extremity EMG activity.

Conclusion

These findings suggest that WBV with appropriate parameters may constitute a promising intervention to treat musculoskeletal degradation after chronic SCI.     

Evidence for cervical muscle morphometric changes on magnetic resonance images after whiplash: A systematic review and meta-analysis

IntroductionMorphometric changes to cervical musculature in whiplash associated disorder have been reported in several studies with varying results. However, the evidence is not clear because only a limited number of cohorts have been studied and one cohort has been reported in multiple publications. The aim of this study was to assess the evidence for cervical muscle morphometric changes on magnetic resonance (MR) images after whiplash using a systematic review with meta-analysis.Materials and methodsPubMed, MEDLINE and Cochrane Library were searched without language restriction using combinations of the MeSH terms “muscles”, “whiplash injuries”, and “magnetic resonance imaging”. Studies of acute and chronic whiplash were included if they compared whiplash and control cervical spine muscle morphometry measurements from MR images. The search identified 380 studies. After screening, eight studies describing five cohorts (one acute, three chronic, one both acute and chronic) met the inclusion criteria. Participant characteristics and outcome measures were extracted using a standard extraction format. Quality of eligible studies was assessed using the Newcastle-Ottawa Scale. Muscle cross-sectional area (CSA) and fat infiltrate (MFI) for acute and chronic whiplash cohorts were compared using mean difference and 95% confidence intervals. Meta-analysis models were created when data from more than two eligible cohorts was available, using inverse-variance random-effects models (RevMan5 version 5.3.5).ResultsQuality assessment was uniformly good but only two studies blinded the assessor. Analysis of the acute cohorts revealed no consensus with respect to CSA. MFI was not measured in the acute cohorts. Analysis of the chronic cohorts revealed CSA is probably increased in some muscles after whiplash but there is insufficient evidence to confirm whether MFI is also increased. Because the available data were limited, meta-analyses of only multifidus were performed. In chronic whiplash multifidus CSA was significantly increased at C5 (Z = 3.51, p < 0.01) and C6 (Z = 2.66, p < 0.01); and MFI was significantly increased at C7 only (Z = 2.52, p < 0.01) but the heterogeneity was unacceptably high (I² = 83%).ConclusionsThe strength of the evidence for cervical muscle morphometric changes on MR images after whiplash is inconsistent for CSA and MFI. Future study designs should be standardised with quantification of three-dimensional muscle morphometry.     

颈髓损伤晚期损伤程度及损伤后瘫痪时间对肺功能的影响

目的:探讨颈髓损伤晚期患者损伤程度及损伤后瘫痪时间对肺功能的影响。方法:对40例颈髓损伤晚期患者进行ASIA运动评分,并测定最大肺活量(VCM AX)、时间肺活量(FVC)、第一秒最大呼气量(FEV1)、呼气高峰流量(PEF)及损伤后瘫痪时间,观察各项肺功能指标变化。结果:40例颈髓损伤晚期患者肺功能皆下降,ASIA运动评分与VCM AX、FVC、FEV1、PEF成正相关;完全性损伤组与不完全性损伤组间VCM AX、FVC、FEV1、PEF有显著性差异(P<0.05);本组完全性损伤组或不完全性损伤组中,C3~5与C6~8节段损伤患者的VCM AX、FVC、FEV1、PEF均无显著性差异;损伤后瘫痪时间与VCM AX无相关性,而与FVC、FEV1、PEF呈正相关。结论:颈髓损伤晚期患者肺功能均下降,肺功能改变与脊髓损伤程度及损伤后瘫痪时间有关。     

宫颈环扎术治疗宫颈机能不全致习惯性流产52例临床分析

目的探讨宫颈环扎术治疗宫颈机能不全致习惯性流产的疗效。方法对确诊为宫颈机能不全致习惯性流产患者再次妊娠,孕12～18周时,采用宫颈环扎术,术前术后给予防感染及防宫缩安胎处理。结果 52例行宫颈环扎术的孕妇,妊娠达37～38周者9例,占17.3%;38～40周者38例,占73%;大于40周者5例9.7%。均获得活婴。结论宫颈环扎术能够有效防治宫颈机能不全导致的习惯性流产。     

后路颈椎术后重建肌肉骨性止点对颈半棘肌形态及功能的影响

脊髓型颈椎病病因多为脊髓受压而导致的一系列神经功能障碍.后路颈椎椎管扩大椎板成形术是治疗脊髓型颈椎病的重要术式[1],该术式术后颈椎后凸畸形发生率较低,更好地保留了颈椎活动度,能获得较为确切的神经功能改善.近年来,部分后路颈椎手术术后患者发生颈椎不稳、颈椎屈伸功能受限或明显的轴性症状等并发症[2].上述症状与颈部肌肉萎...     

Intrinsic muscle contribution to the metacarpophalangeal joint flexion moment of the middle, ring, and small fingers

PURPOSE: To analyze the relative contribution of the intrinsic muscles to the flexion moment potential of the metacarpophalangeal (MCP) joints of the middle, ring, and small fingers and to calculate the moment potential loss occurring with deep motor branch, low, or high ulnar nerve palsy or low median nerve palsy. METHODS: Eleven fresh cadaver hands were used. A small wire sutured to each tendon was connected to an excursion transducer containing a constant-tension spring. The tendon excursion and the MCP joint rotation were measured simultaneously during 10 to 16 cycles of passive flexion/extension cyclic motion. The moment arm was calculated from the tendon excursion-joint rotation curve as the derivative of the curve. The flexion moment potential was calculated by multiplying the moment arm with the known tension fractions of the muscles. RESULTS: When the MCP joint was at 0 degrees of flexion the relative moment potential contributions of the intrinsic muscles to MCP joint flexion were 8%, 13%, and 28% in the middle, ring, and small fingers, respectively. Moment potential losses were 7%, 13%, and 6% in the middle, ring, and small fingers, respectively, in deep motor branch ulnar nerve palsy. In low ulnar nerve palsy the losses were 7%, 13%, and 28%, respectively. In high ulnar nerve palsy they were 7%, 64%, and 82%, respectively. Low median nerve palsy, however, resulted in a moment potential loss at the middle finger MCP joint of less than 2%. CONCLUSIONS: The relative contribution of the intrinsic muscles to the total flexion moment at the MCP joint was different for each finger. The small finger had a large intrinsic contribution, primarily because of the larger moment arms of the hypothenar muscles.     

Effect of age on cervical spine injury in pediatric population: a National Trauma Data Bank review

Background

The objective of this study was to characterize the incidence, risk factors, and patterns of cervical spine injury (CSI) in different pediatric developmental ages.

Methods

A retrospective review of the National Trauma Data Bank was conducted for the period of January 2002 through December 2006 to identify pediatric patients admitted following blunt trauma. Patients were stratified into 4 developmental age groups: infants/toddlers (age 0-3 years), preschool/young children (age 4-9 years), preadolescents (age 10-13 years), and adolescents (age 14-17 years). Patients with a CSI were identified by the International Classification of Diseases, Ninth Revision codes. Demographics, clinical injury data, level of CSI, and outcomes were abstracted and analyzed.

Results

A total of 240,647 patients met the inclusion criteria. Of these, 1.3% (n = 3,035) sustained a CSI. The incidence of CSI in the stratified age groups was 0.4% in infants/toddlers, 0.4% in preschool/young children, 0.8% in preadolescents, and 2.6% in adolescents. The level of CSI (upper [C1-C4] vs lower [C5-C7]) according to the age groups was as follows: infants and toddlers, 70% vs 25%; preschool/young children, 74% vs 17%; preadolescents, 52% vs 37%; and adolescents, 40% vs 45%, respectively. The adjusted risk for CSI increased 2-fold in preadolescents and 5-fold in adolescents.

Conclusion

The incidence of pediatric CSI increases in a stepwise fashion after 9 years of age. We noted an increase in lower CSI and a decrease in upper CSI after the age of 9 years. The incidence of upper CSI compared with lower CSI was higher in preadolescents (52% vs 37%) and almost equal in adolescents (40% vs 45%).     

Trunk muscle cocontraction: the effects of moment direction and moment magnitude.

This study investigated the cocontraction of eight trunk muscles during the application of asymmetric loads to the torso. External moments of 10, 20, 30, 40, and 50 Nm were applied to the torso via a harness system. The direction of the applied moment was varied by 30 degrees increments to the subjects' right side between the sagittally symmetric orientations front and rear. Electromyographic (EMG) data from the left and right latissimus dorsi, erector spinae, external oblique, and rectus abdominus were collected from 10 subjects. The normalized EMG data were tested using multivariate and univariate analyses of variance procedures. These analyses showed significant interactions between the moment magnitude and the moment direction for seven of the eight muscles. Most of the interactions could be characterized as due to changes in muscle recruitment with changes in the direction of the external moment. Analysis of the relative activation levels, which were computed for each combination of moment magnitude and direction, indicated large changes in muscle recruitment due to asymmetry, but only small adjustments in the relative activation levels due to increased moment magnitude.     

颈交感神经网切除对肢体痉挛骨骼肌肌电图、酶及肌纤维结构的影响

目的　探讨交感神经切除后 ,痉挛肌肉内肌电图、酶及肌纤维结构的改变。方法　将2 0只Wistar大白鼠作成痉挛性模型 ,分成两组 ,随机选择 1组行颈总动脉周交感神经网剥脱切除及颈上节交感神经切除术 ,另 1组作为对照 ,于术后第 8天用Dantec肌电图仪观察肱三头肌F波幅度。术后第 2 0天切取两组大鼠部分肱三头肌组织 ,采用 (Ellman)爱尔蒙法测定肌组织内乙酰胆碱酯酶活性 ,在IBAS图像分析仪上观察两组肌组织内快收缩肌纤维与慢收缩肌纤维的改变情况。结果　交感神经切除后 ,F波幅度及乙酰胆碱酯酶活性明显下降 ,分别从 (0 .3 778± 0 .160 0 )mm降至 (0 .15 5 2± 0 .0 80 0 )mm (P <0 .0 1) ;(3 .3 7± 1.0 1)U / g降至(0 .84± 0 .65 )U / g(P <0 .0 1) ,快肌纤维明显减少 ,从 (2 75 72 7.3 1± 982 40 .2 3 )U/m2 降至 (8814 8.2 2± 3 5 111.18)U /m2 (P <0 .0 1) ,慢肌纤维显著增加 ,由 (4 2 710 .78± 2 885 8.3 7)U/m2 增至 (179184.73± 870 44 .5 9)U/m2(P <0 .0 1)。结论　交感神经切除后痉挛肌肉兴奋性下降     

颈椎不稳在椎动脉型颈椎病发病中的意义

椎动脉型颈椎病是中老年颈椎病患者中最常见的类型,长期以来医学界对其发病机制认识不统一,因此导致此病命名各异,如颈性眩晕,Barre—Lieou综合征,椎一基底动脉缺血综合征,颈交感神经综合征等。门诊经常见到眩晕的患者经多科室诊治仍不能确诊,即使诊为椎动脉型颈椎病,也给予扩血管药物、中药、制动、理疗、牵引等保守治疗,使得症状反复发作,给患者带来极大痛苦和精神压力。将其他型颈椎病合并有头痛、眩晕,旋颈试验阳性,有猝倒病史的患者进行手术治疗,疗效满意,现将结果报告如下。