Human muscle fiber fine structure: morphometric data on controls.

Muscle fiber fine structure was quantitatively analyzed in 70 longitudinally and 65 transversely sectioned fibers from 10 control subjects without weakness. The average mitochondrial fraction of the fiber volume is close to 4 percent and the mean size of a mitochondrion is about 0.1 mum2. The sarcotubular surface area per unit fiber volume is close to 1.5 mum2/mum3 in transverse sections and 0.65 times this value in longitudinal sections. Only one-third of all fibers contain lipid droplets in the sectioned plane, and for all fibers the droplets account for approximately 0.12 percent of the fiber volume. Variations with the age and sex of the subjects and with different muscles were analyzed and the feasibility of typing human muscle fibers at the ultrastructural level was evaluated.

Failure of inactivation of Duchenne dystrophy X-chromosome in one of female identical twins.

Duchenne muscular dystrophy manifested in one of girl twins. The twins were monozygous on the basis of red cell and HL antigens and skin graft compatibility. Karyotyping, including banding techniques, showed a normal number of chromosomes and a normal configuration of the X-chromosome in both twins. The twins were identical in appearance until symptoms of Duchenne dystrophy developed in one at age 4 years. The maternal uncle had classic Duchenne dystrophy; the mother and the nonmanifesting twin showed evidence of being heterozygous for Duchenne dystrophy. The phenotypic difference in monozygous twins is readily explained by lyonization of the X-chromosome after twinning has occurred. The findings substantiate the existence of Duchenne dystrophy manifesting in females with normal karyotypes.

Pathogenesis and prophylaxis of postlaminectomy deformity of the spine after multiple level laminectomy: difference between children and adults.

The pathogenesis of postlaminectomy spinal deformity and instability in children was evaluated by reviewing appropriate roentgenographic findings. First, we reviewed spine roentgenograms of patients below 40 years of age who underwent spinal fusion for deformity and instability of the spine developing after a multiple level laminectomy. Two types of deformity were recognized on the roentgenograms: increased mobility between the vertebral bodies and wedging deformity of the ventral aspect of the vertebral bodies. Second, we did a follow-up study of another group of patients who had undergone laminectomy. We found the same two types of deformity in children, but not in adult patients. The incidence of deformity was higher after laminectomies of the cervical or cervicothoracic region than after lumbar laminectomies. Our data suggest that postlaminectomy spinal deformity can develop in children without irradiation or facet injury. The deformity is due to a wedging change in the cartilaginous portion of the vertebral body and to the viscoelasticity of ligaments in children. When treatment of this complication becomes necessary, anterior fusion may be effective in arresting progression. Prophylactic measures against the development of deformity are discussed. Our hypothesis concerning the mechanism of development of this complication supports the rationale of osteoplastic laminar resection and reconstruction instead of laminectomy, particularly in the management of children.

Incidence of spinal column deformity after multilevel laminectomy in children and adults.

Fifty-eight patients, all less than 25 years of age, underwent multilevel laminectomy for conditions that in themselves do not usually cause spinal deformity. Spinal deformity developed in 46% (12 of 26) of the patients who were less than 15 years of age, but in only 6% (two of 32) of the patients aged 15 to 24 years. Spinal deformity developed in all (100%) patients who had cervical laminectomy, in 36% of those who had thoracic laminectomy, and in none (0%) of those who had lumbar laminectomy. There was no correlation between the occurrence of deformity and sex, number of laminae removed, neurological conditions after laminectomy, or length of time after surgery.

Radial growth plate injury in a female gymnast.

Radial growth plate injury is a cause of wrist pain in female gymnasts. The mechanism of injury and its relationship to dowel grips, now standard gymnastic equipment, are considered. An athlete's response to a treatment approach emphasizing moderation and protection is described.

Opening-wedge osteotomy for angular deformities of long bones in children.

Mild angular deformities associated with a mild limb-length discrepancy of long bones in children can be treated effectively with opening-wedge osteotomy with insertion of a specially prepared autogenous tricortical iliac-crest bone graft and with minimum or no internal fixation. Thirty-one osteotomies in twenty-six children satisfactorily corrected the deformities so that the angulation and length of the bone were comparable with the values on the normal, contralateral side. Physeal arrest or ipsilateral excision of a physeal bar was performed either concomitantly or at a separate operation in twenty-one of the twenty-six patients, to aid in the treatment of the limb-length discrepancy. Opening-wedge osteotomy is applicable for correction when the angular deformity is 25 degrees or less and the limb-length discrepancy is, or will be, twenty-five millimeters or less at maturity.

Salter-Harris Type-IV injuries of the distal tibial epiphyseal growth plate, with emphasis on those involving the medial malleolus.

Salter-Harris Type-IV fractures of the epiphysis extend through the articular cartilage, epiphysis, physis, and metaphysis and have a high rate of complications secondary to premature partial closure of the physis. In this study we attempted to determine which Type-IV fractures of the distal end of the tibia result in premature partial closure, how the various treatment modalities affect the risk of premature physeal closure, and how the complication itself might be best managed. Thirty-two Type-IV fractures of the distal end of the tibia were seen at the Mayo Clinic during a five-year period. Eighteen injuries involved the medial malleolus, thirteen were so-called triplane fractures, and one was a fracture of the lateral part of the plafond. In the eighteen ankles with a fracture that involved the medial malleolus, extension of the fracture into the metaphysis could often be appreciated only on oblique roentgenograms. The patients' ages at the time of fracture ranged from one year and one month to fifteen years and six months old. In nine of the eighteen tibiae with a fracture of the medial malleolus premature partial closure of the distal physis developed, resulting in angular deformity or limb-length discrepancy sufficient to require operative treatment (epiphyseodesis, corrective osteotomy, or excision of a physeal bar). A physeal bar was best detected by tomograms made in two planes and by scanograms. Bar formation may be treated by excision of the bar, arrest of the whole physis, osteotomy, or combinations of these procedures. Of the thirteen patients with a triplane fracture and the one with a Type-IV fracture of the lateral part of the plafond, all fourteen were near maturity at the time of injury, and no growth-arrest problems developed.

Fractures of the proximal tibial epiphysis.

Fractures of the proximal tibial epiphysis are rare. A series of twenty-eight fractures classified according to the Salter-Harris method showed that nine were Type II and eight, Type IV. Lawn-mower injuries, a previously unreported mode of injury for this fracture, caused five of the eight Type-IV fractures and were associated with the worst prognosis by far. Two Type-V fractures in the proximal tibial epiphysis, previously unreported, are described.

Pathological fractures through non-ossifying fibromas. Review of the Mayo Clinic experience.

Twenty-three cases of a pathological fracture through a lesion verified histologically as non-ossifying fibroma were seen over a forty-nine-year period. The average age of the patients at the time of fracture was twelve years. All fractures except one were located in the lower extremity, most frequently in the distal end of the tibia (ten). The percentage of bone occupied by the fibroma in the transverse plane exceeded 50 per cent on both the anteroposterior and the lateral radiographs in every patient. The vertical length was always the maximum dimension and in all non-fibular lesions exceeded thirty-three millimeters. Treatment consisted of cast immobilization with biopsy at a later date, simple curettage, curettage and autogenous bone-grafting, or segmental resection of fibular lesions.

Reduction of radiation exposure during radiography for scoliosis.

To reduce the radiation exposure received by young scoliosis patients during treatment, six changes in technique were instituted: (1) a posteroanterior projection, (2) specially designed leaded acrylic filters, (3) a high-speed screen-film system, (4) a specially designed cassette-holder and grid, (5) a breast-shield, and (6) additional filtration in the x-ray tube the thyroid, breast, and abdominal areas were made on an Alderson phantom. They revealed an eightfold reduction in abdominal exposure for both the posteroanterior and the lateral radiographys. There was a twentyfold reduction in exposure to the thyroid for the posteroanterior radiography from 100 to less than five milliroentgens and for the lateral radiograph there was a 100-fold reduction from 618 to six milliroentgens. For the breasts there was a sixty-ninefold reduction from 344 to less than five milliroentgens for the posteroanterior radiography and a fifty-fivefold reduction from 277 to less than five milliroentgens for the lateral radiograph. These reductions in exposure were obtained without significant loss in the quality of the radiographs and in most instances with an improvement in the over-all quality of the radiograph due to the more uniform exposure.

Management of deformities of the forearm in multiple hereditary osteochondromas.

A patient with multiple hereditary osteochondromas may have any of several severe deformities of the forearm, the most common of which are ulnar deviation of the wrist associated with relative shortening of the ulna, bowing of either or both of the bones of the forearm, shortening of the forearm, and late dislocation of the radial head. The natural history of these deformities is progression, with variable weakness, functional impairment, and cosmetic deformity of the extremity. We describe the results, after a follow-up of at least two years, in eighteen patients who underwent major surgical procedures: excision of the osteochondromas (ten patients), ulnar lengthening with excision of the osteochondromas (three patients), and ulnar lengthening with radial hemiepiphyseal stapling (seven forearms of five patients). Early excision of the osteochondromas alone did not slow the progression of the deformity. Ulnar lengthening did, on occasion, correct the ulnar drift at the wrist, but the relative shortening of the ulna recurred. Distal radial hemiepiphyseal stapling should accompany ulnar lengthening if radiocarpal angulation or subluxation of the lunate occurs with ulnar shortening. Deformities of the forearm should be treated early and aggressively to prevent disability.

The association of scoliosis and congenital heart defects.

The effects of cardiac surgery on patients with congenital heart defects and the subsequent development of scoliosis were studied. A group of 998 patients with congenital heart defects who were less than sixteen years old were operated on at the Mayo Clinic during the ten-year period 1950 through 1959. Standing roentgenograms of the spine were made of 377 of the patients ten years or more after surgery. The ages of the patients at follow-up ranged from ten years and seven months to thirty-five years and three months, with a mean age of twenty-one years and four months. The average length of follow-up was fourteen years and eleven months. Of the 377 patients, thirty-two (8.5 per cent) had curves greater than 20 degrees. The female:male ratio of patients with congenital heart defects was 1:1, whereas of those who developed scoliosis it was 5:3. There was no correlation between scoliosis and the following: patient's sex, cardiac abnormality, size or side of the heart, side of the aortic arch, presence of cyanosis, age at surgery, number and type of surgical incisions, number and side of ribs removed, or number and type of surgical procedures.

Acquired spondylolysis and spondylolisthesis in the young child.

The cause of spondylolysis and spondylolisthesis remains unknown. There is increasing evidence that the defect in the pars interarticularis is due to fatigue fracture rather than being of congenital origin. We describe the youngest patient on record with spondylolysis and spondylolisthesis in whom roentgenograms that showed no abnormality had previously been taken. This case supports the hypothesis that spondylolysis and spondylolisthesis are acquired and not congenital, even when discovered in a very young child.

Spinal column deformity and instability after lumbar or thoracolumbar laminectomy for intraspinal tumors in children and young adults.

STUDY DESIGN: A retrospective study about the occurrence of spinal column deformity or instability after multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors in children and young adults. OBJECTIVES: To analyze the long-term clinical and radiographic outcome of these patients, and to specify factors that affect the occurrence of postlaminectomy spinal column deformity and instability. SUMMARY OF BACKGROUND DATA: Spinal column deformity is not uncommon after multilevel cervical or thoracic laminectomies for removal of intraspinal tumors in children. Its incidence in the lumbar and thoracolumbar spine reportedly is low. METHODS: Thirty-six consecutive patients (23 male, 13 female) underwent multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors from 1966 to 1989. Twelve patients were aged 17 years or younger ("children and adolescents"; mean age, 11 years), and 24 were aged 18-30 years ("young adults"; mean age, 24 years). All patients had preoperative, immediate postoperative, and follow-up clinical and radiographic examinations. RESULTS: At a mean follow-up period of 14 years (range, 4-28 years), six patients (16.6%) had spinal deformity (lordosis or thoracolumbar kyphosis associated with scoliosis), and four (11%) had spondylolisthesis. Spinal column deformity occurred in 33% of children and adolescents and in 8% of young adults. Spondylolisthesis occurred in 16.6% of children and adolescents and in 8% of young adults. Three patients had fusion for spinal column deformity. Pain was present in eight patients, and other neurologic signs and symptoms were found in 18. There was an increased incidence of postoperative spinal deformity in patients who had more than two laminae removed (P < 0.01) or a facetectomy performed at the time of the initial operation (P < 0.05). There was no association between the occurrence of the deformity and sex, neurologic condition after laminectomy, or length of follow-up period. CONCLUSIONS: Spinal deformity or instability after multilevel lumbar or thoracolumbar total laminectomy is not uncommon in children and adolescents. Limiting laminae removal and facet destruction may decrease this incidence. Fusion may be required to correct post-laminectomy deformity and to stabilize the spine.

Leg aches.

In the investigation of children with leg aches, it is essential to identify those with demonstrable underlying organic diseases. Growing pains is a poorly named, nebulous entity that can be diagnosed only by exclusion. The greatest diagnostic error is to make a diagnosis of growing pains while overlooking some serious underlying condition.

The use of computerised tomography in dislocation of the hip and femoral neck anteversion in children.

Computerised tomography is useful in the diagnosis of abnormalities of the hip in children, particularly in assessing the size and shape of the acetabulum, the position and congruity of the femoral head relative to the acetabulum, and the degree of femoral anteversion or retroversion. It is most useful when limited hip movement and previous operations preclude adequate clinical examination and assessment by routine radiographic techniques. It is not recommended for routine use in screening congenital dislocation of the hip or in diagnosis or follow-up of Perthes' disease or slipped capital femoral epiphysis.

Hematogenous pyogenic osteomyelitis in children.

Early diagnosis of acute hematogenous osteomyelitis is difficult. The diagnosis can be positively established only by isolation of the organism from bone or by histologic confirmation. The diagnosis should always be suspected when clinical signs are suggestive. In these cases aspirated material should be obtained for culture and the patient should be treated with antibiotics and observed closely. If the clinical response is good and no bone destruction occurs, surgical intervention may not be necessary. If the clinical response is not satisfactory or if bone destruction occurs, surgical treatment should be carried out to drain the area and to identify the etiologic organism. When osteomyelitis is associated with joint involvement, the prognosis is poor, and our data show no obvious improvement even with long-term antibiotic therapy. The key is prevention by early recognition and treatment. If culture fails to isolate a pathogenic organism, the prognosis appears to be good. Overall, in recent years the prognosis of hematogenous osteomyelitis has continued to improve, probably as a result of early detection and better antibiotic therapy.

Hematogenous osteomyelitis in children.

Acute hematogenous osteomyelitis is the formation of pus within bone. Bone destruction and spread of the infection to contiguous areas may be rapid and significantly alter the prognosis and potential for complications. Bacteriologic isolation of the infecting organism is essential to determine the appropriate antibiotic to be used. Mechanical removal of pus is necessary for optimal antibiotic function. Surgical decompression should be performed if aspiration reveals pus or if roentgenograms show evidence of bone destruction.

Fungal osteomyelitis in children.

Fungal osteomyelitis is rare in children. Eumycetoma osteomyelitis occurs by direct external inoculation. Suspicion should be aroused when there are intermittent or persistent draining sinuses, even if bacterial cultures are positive. Treatment must be aggressive and should include radical local debridement. The quest for effective systemic chemotherapy should continue. Persistent drainage, ascending infection, and a functionless extremity are reasons for considering amputation.

Disk-space infection in children.

Disk-space infection and vertebral osteomyelitis are two separate entities. Disk-space infection is an isolated soft tissue infection usually caused by coagulase-positive S. aureus. There is reactive osteolytic and osteoblastic activity in the two adjacent vertebral end-plates. Treatment by immobilization alone usually produces a satisfactory outcome. A satisfactory outcome can be accomplished by bed rest or use of a corset or cast. Infrequently, needle biopsy or open biopsy may be necessary for the diagnosis and treatment of resistant disease; this usually is needed in an older child. Surgery and antibiotics are indicated in patients with persistent symptoms, persistent elevation of the sedimentation rate, and failure of the radiologic changes to improve. The findings and recommendations concerning children should not be applied to adults.