Cross-sectional area of lumbar spinal muscles and vertebral endplates: a secondary analysis of 91 computed tomography images of children aged 2-20.

Spinal muscle cross-sectional area has been highly associated with spinal pathology. Despite the medium-high prevalence of spinal pathology in children, there is very limited knowledge regarding muscle size and growth pattern in individuals younger than 20 years of age. The aim of this study is to analyze the change in size and symmetry of spinal muscles (erector spinae, multifidus, psoas and quadratus lumborum) in children 2-20 years of age. We studied reformatted images from 91 abdominal computed tomographic scans of children aged 2-20 years, from an existing imaging dataset. The cross-sectional area of the muscles was bilaterally measured parallel to the upper endplate of the lumbar vertebrae L3-L5 and at true horizontal for S1. The cross-sectional area of the upper vertebral endplate was measured at spinal levels L3-L5. Results were analyzed according to six groups based on children's age: 2-4 years (group 1), 5-7 years (group 2), 8-10 years (group 3), 11-13 years (group 4), 14-16 years (group 5) and 17-20 years (group 6). Vertebral endplate and spinal muscles cross-sectional area increased with age. Two patterns were observed: Endplate, psoas and quadratus lumborum increased up to our 6th oldest age group (17-20), and multifidus and erector spinae reached their largest size in the 5th age group (14-16). The epaxial muscles (erector spinae and multifidus) reached their maximal cross-sectional area before skeletal maturity (18-21 years of age). The hypaxial muscles (psoas and quadratus lumborum) continued to increase in size at least until spinal maturity. Contributing factors for the differences in developmental pattern between the epaxial and hypaxial muscles might include functional, embryological and innervation factors. In conclusion, this research is the first to describe the cross-sectional area of spinal muscles in children. Future longitudinal studies are needed for further understanding of muscle development during childhood and adolescence. LEVEL OF EVIDENCE: level 2b, Retrospective cohort study.

Development of Pelvic Incidence and Lumbar Lordosis in Children and Adolescents.

Pelvic incidence (PI) is a measure of the sagittal orientation of the sacrum relative to the acetabula and is not dependent on posture. In asymptomatic adults, PI correlates with lumbar lordosis. Lumbar lordosis is shown to increase with age following the onset of unassisted bipedal locomotion in children, but to what extent PI changes in relation to lumbar lordosis during skeletal maturation is unclear. The purpose of this study is to understand how PI, lumbar lordosis, and age are related in children and adolescents. PI, supine lumbar lordosis (SLL), and individual wedging angles of the lumbar vertebral bodies were measured on mid-sagittal reformatted images from 144 abdominal computed tomographic scans of individuals aged 2-20 years old, divided into three separate age categories representing pre-growth spurt (ages 2-9), growth spurt (10-15), and post-growth spurt (16-20). Our results showed that, while SLL significantly increased with age during development, PI did not. Despite the fact that PI hardly changed with age, the difference between PI and SLL decreased nonlinearly with age. SLL did not correlate with PI in the youngest age category, but positively correlated with PI in the middle and oldest age categories. The relationship between lumbar lordosis and PI, which is correlated in adults, was significant in our older age categories and not in our youngest age category. Our results indicate that PI in children and adolescents may have some predictive value for adult lumbar lordosis. Anat Rec, 302:2132-2139, 2019. © 2019 American Association for Anatomy.

Cervical lordosis: the effect of age and gender.

BACKGROUND CONTEXT: Cervical lordosis is of great importance to posture and function. Neck pain and disability is often associated with cervical lordosis malalignment. Surgical procedures involving cervical lordosis stabilization or restoration must take into account age and gender differences in cervical lordosis architecture to avoid further complications. PURPOSE: Therefore, the purpose of the present study was to evaluate differences in cervical lordosis between males and females from childhood to adulthood. STUDY DESIGN: This is a retrospective descriptive study. PATIENT SAMPLE: A total of 197 lateral cervical radiographs of patients aged 6-50 years were examined. These were divided into two age groups: the younger group (76 children aged 6-19; 48 boys and 28 girls) and the adult group (121 adults aged 20-50; 61 males and 60 females). The retrospective review of the radiographs was approved by the institutional review board. METHODS: On each radiograph, six lordosis angles were measured including total cervical lordosis (FM-C7), upper (FM-C3; C1-C3) and lower (C3-C7) cervical lordosis, C1-C7 lordosis, and the angle between foramen magnum and the atlas (FM-C1). Wedging angles of each vertebral body (C3-C7) and intervertebral discs (C2-C3 to C6-C7) were also measured. Vertebral body wedging and intervertebral disc wedging were defined as the sum of the individual body or disc wedging of C3 to C7, respectively. Each cervical radiograph was classified according to four postural categories: A-lordotic, B-straight, C-double curve, and D-kyphotic. RESULTS: The total cervical lordosis of males and females was similar. Males had smaller upper cervical lordosis (FM-C3) and higher lower cervical lordosis (C3-C7) than females. The sum of vertebral body wedging of males and females is kyphotic (anterior height smaller than posterior height). Males had more lordotic intervertebral discs than females. Half of the adults (51%) had lordotic cervical spine, 41% had straight spine, and less than 10% had double curve or kyphotic spine. Children had similar total cervical lordosis (FM-C7) to adults. The sum of vertebral body wedging for children was more kyphotic-by 7°-than that of adults, whereas the sum of intervertebral disc wedging in children was more lordotic-by11°-than that of adults. Seventy-one percent of the children had lordotic cervical spine, 23% had straight spine, and less than 6% had double curve spine. Gender differences are already apparent in children as girls had higher upper cervical lordosis (FM-C3; C1-C3) than boys do. CONCLUSIONS: Although the total cervical lordosis (FM-C7) did not change between age groups, and between males and females, the internal architecture of the cervical lordosis changed significantly. Practitioners before neck stabilization procedures or correction and restoration should therefore take into account the gender and age differences in cervical lordosis.

Evolution of Spinopelvic Alignment in Hominins.

Spinopelvic alignment refers to the interaction between pelvic orientation, spinal curvatures, and the line of gravity. In a healthy modern human, this alignment is characterized by reciprocal curves/orientation of the sacrum, lumbar lordosis, thoracic kyphosis, and cervical lordosis. In an economic sagittal posture, these curvatures keep the line of gravity close to the center of the acetabulum. The purpose of this study is to explore the spinopelvic alignment in extinct hominins. We examined spinopelvic alignment of a single representative from each of the following hominin groups: Australopithecus, Homo erectus (H. erectus), H. neanderthalensis, and early H. sapiens. Pelvic incidence, lumbar lordosis, thoracic kyphosis, and cervical lordosis for each representative was estimated and compared with that of modern humans. Three basic spinopelvic alignments were found: (1) the sinusoidal alignment with moderate to high spinal curvatures and pelvic incidence found in H. erectus and H. sapiens; (2) the straight alignment with small spinal curvatures and small pelvic incidence found in Neandertal lineage hominins; (3) the compound alignment found in Australopithecus, with moderate pelvic incidence and lumbar lordosis, and nearly straight cervical spine. Our results indicate that balanced upright posture can be achieved in different alignments. Each hominin group solved the requirements of erect posture in a slightly different way. Moreover, we propose the term "cranio-spino-pelvic balance" to substitute "spino-pelvic balance." From an evolutionary perspective, not only changes in the pelvis have conditioned the evolution of the spinal curvatures but also changes in the equilibrium of the head likely also affected this balance. Anat Rec, 300:900-911, 2017. © 2017 Wiley Periodicals, Inc.

Electromyographic activity of voluntarily activated trunk flexor and extensor muscles in post-stroke hemiparetic subjects.

OBJECTIVE: To study the EMG activity of selected trunk muscles during self-initiated voluntary flexion and extension of the trunk in post-stroke hemiparetic subjects, and to compare measurement results to corresponding findings in control subjects. METHODS: Using a sample of 50 patients and 30 control subjects, bilateral EMG activity of the rectus abdominis (RA) and external oblique (EO) muscles was studied during direct trunk flexion, and activity of the lumbar erector spinae (ES) and latissimus dorsi (LD) was studied during straight trunk extension. Variables of timing, magnitude, and temporal synchronization between muscle activity on the paretic and non-paretic sides of the body in the patient group were compared with the same measurements taken from the left and right sides of the body in the control group. RESULTS: Activity of the RA and LD muscles on the affected side of the body was reduced and delayed relative to the unaffected side in the patients and relative to the control subjects. Some deterioration was also observed in the function of the EO muscle, whereas the lumbar ES displayed normal activity on both sides of the body. Trunk velocity during both flexion and extension was slower in the patients than in the controls. CONCLUSIONS: Despite the existence of ipsilateral as well as contralateral higher inputs to axial and to a lesser extent also to more lateral trunk muscles, the function of the superficial abdominal muscles and of the LD muscle is adversely affected by a contralateral stroke. Conversely, the lumbar ES, which can be categorized as local trunk extensors, seem to normally fulfill their anti-gravitational task on both sides of the body.

Motor imagery group practice for gait rehabilitation in individuals with post-stroke hemiparesis: a pilot study.

BACKGROUND: Stroke is the leading cause of adult disability, with walking impairment being a devastating indicator of chronic post-stroke hemiparesis. Limited resources exist for individual treatments; therefore, the delivery of safe group exercise therapy is highly desired. OBJECTIVE: To examine whether the application of group-based motor imagery practice to community-dwelling individuals with chronic hemiparesis improves gait. METHODS: Sixteen individuals with chronic hemiparesis from two community centers participated in the study, with eight from each center. Four participants in each center received five weeks of the experimental intervention, consisting of group-based motor imagery exercises of gait tasks, followed by five weeks of control treatment of motor imagery exercises for the affected upper extremity. Four other subjects in each center received the same treatments in reverse order. Pre- and post intervention measurements included clinical and biomechanical gait parameters. RESULTS: Comparisons within (pre- vs. post) and between treatments (experimental vs. control) indicated no significant change in any gait variable. Nevertheless, the verbal reports of most participants alluded to satisfaction with the experimental intervention and to an increase in self-confidence. CONCLUSIONS: Despite the lack of evidence for the effectiveness of group-based motor imagery practice in improving gait among individuals with chronic hemiparesis, the contrast between the measured outcomes and the positive verbal reports merits further inquiry.

Development of the lumbar lordotic curvature in children from age 2 to 20 years.

STUDY DESIGN: Cross-sectional retrospective study. OBJECTIVE: The purpose of this study was to provide data for the normal values of the lumbar lordotic curvature and segmental angles throughout childhood and to explore the relative contribution of the vertebral bodies and intervertebral discs to the developing lordosis during childhood. SUMMARY OF BACKGROUND DATA: Although early detection of spinal abnormalities such as hyper lordosis or scoliosis is important for preventative intervention, published data regarding normal lordosis development is sparse. The lumbar lordotic curvature is formed by the wedging of the lumbar vertebral bodies and of the intervertebral discs, but there are no data to indicate how these 2 components changes during childhood development. METHODS: Spinal angle parameters were measured on midsagittal reformatted images from 210 abdominal computed tomographic scans of children aged 2 to 20 years. Four different angles were measured: the lordosis angle, the body wedge angle (B), the total segmental angle (S), and the intervertebral disc angle (D). Measurements B, S, and D were taken for each of the 5 lumbar segments. Measurements B and D were used to calculate ΣB, the sum of the lumbar L1-L5 body angles; and ΣD, the sum of the lumbar L1-L5 intervertebral disc angles. Computed tomographic scans were divided into 6 groups according to patients' ages. RESULTS.: The lordosis angle increased from 30° ± 6° in the 2- to 4-year-old group to 44° ± 9° in the 17- to 20-year-old group. The ΣB slightly decreased (less lordotic wedging) with age, whereas the ΣD increased significantly with age. CONCLUSION: Our results indicate that the lordosis angle continues to develop at least until 14 to 16 years of age and that this increase is the result of the increased lordotic wedging of the intervertebral discs. LEVEL OF EVIDENCE: N/A.

Anticipatory postural adjustment in selected trunk muscles in post stroke hemiparetic patients.

OBJECTIVES: To study electromyographic characteristics of anticipatory postural adjustment in axial and lateral, posterior and anterior trunk muscles during the performance of upper-and lower-limb flexion tasks, in subjects with hemiparesis after stroke and to determine the relationship between anticipatory activity and subjects' motor and functional status. DESIGN: A nonrandomized control study. SETTING: Geriatric rehabilitation center in Israel. PARTICIPANTS: Fifty poststroke hemiparetic patients and 30 healthy control subjects. INTERVENTION: Electromyographic activity of the lumbar erector spinae and of the latissimus dorsi muscles was recorded bilaterally during flexion of either arm and from the 2 rectus abdominis and obliquus externus muscles during flexion of either hip. MAIN OUTCOME MEASURES: Muscles' onset latency, cross-correlation values between the temporal activation profile of corresponding pairs and between ipsilateral muscular pairs, symmetry in activation magnitude of corresponding muscles, and relation between electromyographic activity and motor and functional performance RESULTS: Onset latencies of trunk muscles were partially delayed in the patients with longest hindrance displayed by the erector spinae ipsilateral to the flexing arm (P<.04). Temporal synchronization between pertinent muscular pairs was lower in the patients than in the healthy subjects, with significant group differences (P<.05 or lower) in the correlations between ipsilateral pairs of trunk muscles. Activation of the corresponding lateral trunk muscles in the patients was significantly less symmetrical than in the controls (P<.03 or lower) because of reduced activity on the paretic body side, especially on flexing of the paretic limbs. Conversely, in the controls as well as on the nonparetic side of the patients, limb flexion was associated with increased activity in the ipsilateral lateral trunk muscle. The erector spinae muscle in both groups and on both sides was more active on the contralateral side than on the ipsilateral side to the flexing arm. The reduced activity level in trunk muscles on the paretic body side was associated with deficiencies in motor and functional abilities. CONCLUSIONS: Major impairments in the activity of trunk muscles in hemiparetic subjects were manifested in the reduced activity level of the lateral trunk muscles, in delayed onset, and in reduced synchronization between activation of pertinent muscular pairs. These problems were associated with motor and functional deficits and warrant specific consideration during physical rehabilitation of post stroke hemiparetic patients.