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Biomedical subjects

R Hedlund

Publications and source records attributed to R Hedlund.

34 records · Page 2Linked to original sources
PubMed1994

Radiographic changes at the coronal plane in early scoliosis.

The development of structural skeletal changes was evaluated on 132 anteroposterior radiographs of spines from three scoliotic groups with a Cobb angle of up to 30 degrees and a reference control group. Significant wedging of the vertebral bodies and disks at the coronal plane was registered in-curves with a Cobb angle of 4 degrees or more. Asymmetry of the rib-vertebra angle was found in curves with a Cobb angle of 8 degrees or more and was most pronounced in the cranial part of the curves. The early simultaneous occurrence of vertebral and disk wedging suggests the involvement of an extraspinal factor rather than growth disturbance of the vertebral body or of the disk in the early pathomechanism of scoliosis.

Adolescent↗
PubMed1994

Sagittal configuration of the spine and growth of the posterior elements in early scoliosis.

The early changes of the sagittal alignment of the spine and the asymmetry between the posterior and anterior elements were determined on the basis of 134 lateral and 167 anteroposterior radiographs obtained from a control group and from patients with early scoliosis. The radiographs were allocated into four groups according to the degree of the Cobb angle. In thoracic curves with a Cobb angle of more than 8 degrees, the kyphosis and the vertebral sagittal wedge angle decreased in comparison with the control group. The sagittal-wedge angle of the disc did not change significantly with increasing Cobb angle. The pedicle height in relation to the vertebral height, considered to represent the growth of the posterior element in relation to the growth of the anterior element, was not significantly different in the scoliotic groups as compared with the control group. The results indicate that changes of the sagittal configuration of the spine occur early in idiopathic scoliosis and that they are associated with disturbed growth of the vertebral body but not of the posterior elements. These findings seem to reflect a simultaneous deformation in the coronal and sagittal planes rather than a single growth disturbance in any specific plane.

Adolescent↗
PubMed1993

Long-term results of Boston brace treatment on vertebral rotation in idiopathic scoliosis.

The long-term effect of Boston brace treatment was investigated by computed tomography measurements before treatment, after bracing, and at mean follow-up at 8.5 years in 25 patients with idiopathic scoliosis. At follow-up, the pretreatment Cobb angle, the vertebral rotation, the rib hump, and the translation of the apical vertebra were not significantly changed. The sagittal diameter of the thoracic cage was significantly decreased at follow-up. The current study demonstrates that the Boston brace does not improve, but prevents progression of vertebral rotation, translation, rib hump, and Cobb angle in idiopathic scoliosis. The reduced sagittal diameter is noteworthy and may be of importance for cosmesis and pulmonary function.

Adolescent↗
PubMed1993

Long-term results of Harrington instrumentation in idiopathic scoliosis.

The long-term effect of Harrington instrumentation was investigated using posteroanterior radiographs and computed tomographic measurements preoperatively, postoperatively, and at a mean follow-up at 10.8 years in 33 patients with idiopathic scoliosis. No patient was lost from long-term follow-up. At follow-up, the mean Cobb angle was improved by 23.7 (40%) compared with the preoperative findings. The rotation of the apical vertebra was increased significantly. The rib hump, the translation of the apical vertebra, and the sagittal diameter of the thoracic cage were unchanged. At follow-up, the mean thoracic kyphosis was 17.3, and lumbar lordosis was 22.0. This study demonstrated that the long-term effect of Harrington instrumentation was limited to an improved Cobb angle; no correction of the rotational or sagittal deformities were achieved.

Adolescent↗
PubMed1987

Trauma type, age, and gender as determinants of hip fracture.

We determined the trauma type of femoral neck and trochanteric fractures in men and women aged greater than or equal to 20 years in 19, 128 fractures reported to a computerized medical information register during 1972-1981. We found that the earlier known exponential increase of fracture incidence by age started in early adulthood rather than during middle age. An age-related increase was found for each type of injury as well, although the incidence of fractures resulting from severe trauma increased less than that of fractures associated with moderate trauma. The incidence of low-energy fractures in men as well as in women displayed a constant increase rate with age from young adulthood on, impugning the widely held belief that the menopause is a significant risk factor for fractures. The dominating risk factor for proximal femoral fracture in adults appears to be age, irrespective of the cause of injury, with a chronological decline in bone strength as the most likely cause of the exponential increase in the fracture incidence during adult life.

Accidental Falls↗
PubMed1987

Age- and sex-specific incidence of femoral neck and trochanteric fractures. An analysis based on 20,538 fractures in Stockholm County, Sweden, 1972-1981.

The risk of fracturing the proximal femur is high for individuals with metabolic bone disease or with low bone mass associated with advanced age. Incidences of 20,538 trochanteric and femoral neck fractures in adult Swedish men and women, from a computerized medical information register for all hospitals in Stockholm County, were analyzed for age- and sex-dependence. The rate of increase in the occurrence of fracture was nearly constant for both sexes, exponentially increasing with age for men over 20 years old and for women over 30 years old. The incidence of trochanteric and femoral neck fracture for men doubled every 7.8 and 7.0 years, respectively. The doubling rate of fracture incidence for premenopausal women, aged 30 to 49 years, did not significantly differ from that for postmenopausal women, aged 50 to 69 years. These findings suggest that age-associated factors common to both sexes provide the main risk for fracturing the proximal femur. Menopause does not pose a major risk.

Adult↗
PubMed1986

Hip fracture incidence in Stockholm 1972-1981.

We studied the incidence of cervical and trochanteric hip fractures in Stockholm, Sweden from 1972 through 1981. The material, selected from a computerized medical information register, consisted of 11 812 cervical fractures and 8094 trochanteric fractures. The incidence did not change in the age group 50-74 years. In males 75 years of age and older, the incidence of both fracture types caused by moderate trauma increased annually by 5-6 per cent. In females 75 years and older, the incidence of trochanteric fractures caused by moderate trauma increased annually by 6 per cent, whereas the incidence of cervical fractures increased only marginally.

Accidents, Home↗
PubMed1986

Epidemiology of diaphyseal femoral fracture.

The incidence of diaphyseal femoral fracture in adults, aged 20 years and older, was determined in Stockholm County using hospital admission rates. The validity of the data was investigated by a study of the medical records of a sample of 277 cases and also by determining the incidence in a subpopulation of 139 cases using an alternative method. The incidence decreased from age 20 to middle age after which it increased into old age. The age-related increase was more pronounced in women and in fractures caused by moderate trauma. From 1972 to 1981, the incidence of diaphyseal femoral fracture caused by moderate trauma increased annually by 10 per cent in women aged 75 years and older.

Adult↗
PubMed1985

Influence of the blood-brain pH gradient on brain phenobarbital uptake during status epilepticus.

Brain uptake and blood concentrations of phenobarbital were determined in rats during pentylenetetrazol-induced status epilepticus and compared to nonconvulsing controls. Brain phenobarbital concentrations and the brain-to-blood phenobarbital ratio were increased 2-fold in freely convulsing animals as compared to controls. The degree of systemic acidosis during motor convulsions was greater than the degree of brain acidosis. Because phenobarbital is a weak acid, this pH gradient favors movement of phenobarbital into the brain during status epilepticus. Motor paralysis prevented the development of systemic acidosis and the brain-blood partition of phenobarbital was similar to that of nonconvulsing controls. Blood phenobarbital concentrations were slightly higher in animals paralyzed during status as compared to controls, presumably due to hemodynamic effects of convulsions. These studies, as well as our previous studies with lidocaine, support the idea that the brain-blood pH gradient is an important determinant of drug uptake by the brain during seizures.

Animals↗
PubMedDate not supplied

The incidence of femoral shaft fractures in children and adolescents.

We report the incidence of fractures by sex and age based on 851 femoral shaft fractures from specific types of trauma. The maximum incidence occurred between 2 and 3 years of age, and the total incidence was 2.6 times higher in boys than in girls. In 438 cases the fractures were caused by falls and in 413 cases by traffic accidents. Fractures reported to be caused by falls were most common in children 2 and 3 years of age. Because child abuse has been shown to be involved in the majority of such fractures in early infancy, the data demonstrate the possible magnitude of this problem. Traffic accidents were most common in the oldest age groups, reaching 3.7 cases/10,000 population/year in boys 16 and 17 years of age. Although all fractures were more common during the periods of the fastest skeletal growth, the difference in incidence between different causes indicated that environmental factors are more important than endogenous factors for the risk of fracture.

Accidents, Traffic↗