Orthopaedics in the pediatric office.
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Adolescent↗
Biomedical subjects
W P Bunnell
Publications and source records attributed to W P Bunnell.
Serotonergic response to spinal distraction trauma in experimental scoliosis.
The effects of distraction injury to the spinal cord on serotonin (5HT) content and metabolism in a rat model of scoliosis were studied. Previous studies in this laboratory (Salzman et al., 1987a) have identified the 5HT response as a major component of the posttraumatic progression of spinal injury after impact trauma in the rabbit. The present study was designed to determine the universality of this response by examining a different model of injury in a different species. The results demonstrate that distraction trauma in the rat, like impact injury in the rabbit, is associated with a rapid and robust increase in the local spinal cord content and metabolism of 5HT and a long-term depletion of 5HT below the site of injury. The roles of the blood platelet and the raphe-spinal tract in the acute response and the disruption of axoplasmic transport during the chronic phase of injury are discussed.
Animals↗
The somatosensory evoked potential predicts neurologic deficits and serotonergic pathochemistry after spinal distraction injury in experimental scoliosis.
The validity of the somatosensory evoked potential as an intraoperative spinal cord monitor was evaluated in an experimental model of scoliosis in the rat and a Harrington distraction model of injury. Under these conditions, it was found that any change in latency or amplitude of the major negative wave above a certain level was a significant predictor of an adverse neurologic outcome. Changes in latency of 4% or greater and changes in amplitude of 50% or greater were unequivocal indicators of spinal cord injury. Postmortem analyses of the spinal neurotransmitter serotonin revealed that apparent false-positive results of the SEP were, in fact, true-positive results.
Animals↗
Experimental scoliosis in the rat. I. Methodology, anatomic features and neurologic characterization.
The purpose of this study was to develop a simple and reproducible model of scoliosis in the rat without producing direct trauma to the spine, in order to both provide a system for the study of human scoliosis and to ultimately study the conditions under which distraction-induced trauma might occur. Right lateral curvatures were produced in three groups of rats (N = 36, 59, 25) at 18-21 days of age by suturing the inferior angle of the scapula to the ipsilateral bony pelvis. In the first group of animals, it was found that a minimum period of 6 weeks of tethering was required in order to produce permanent structural curvatures after release of the tethering sutures. In the second group of rats, a number of morphologic and histologic changes characteristic of human scoliosis were noted, including apical wedging, deviation of the apical spinous process, pelvic asymmetry, rib hump deformity, vertebral rotation, displacement of the nucleus pulposus, disorganized columnization of disc cartilage cells, and an increased number of Type I muscle fibers in paravertebral muscle on the convex side of the curve. Finally, in the third group of rats, a mild spasticity was seen in the ipsilateral hindlimb in approximately one-third of the animals with curvatures greater than 40 degrees. This spasticity was not associated with a change of latency or amplitude of the somatosensory-evoked potential (SSEP). Each curvature group displayed SSEP characteristics that were not statistically different from unoperated control animals. These results indicate the validity of this model system for the study of scoliosis, and, in particular, its usefulness for the study of operative-induced trauma.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Neuropathic spinal arthropathy in congenital insensitivity to pain.
Neuropathic arthropathy developed in the lumbar spine of a 28-year-old woman with congenital insensitivity to pain. Progressive spinal instability and destruction occurred at the L1-L2 interspace, with resultant kyphosis. Successful arthrodesis was obtained with staged posterior and anterior procedures.
Arthropathy, Neurogenic↗
Experimental scoliosis in the rat. II. Biomechanical analysis of the forces during Harrington distraction.
The purpose of this study was to characterize the forces resulting from Harrington distraction of the spine in an experimental model of scoliosis in the rat, in order to establish both the similarity of this model to human scoliosis and identify potential force parameters that may be useful for clinical decision-making. Harrington distraction was performed in 36 rats that had been made scoliotic 9-12 weeks earlier by the method described in the previous paper. Distractions were carried out in discrete and timed steps until separation of the vertebral laminae (mechanical failure) occurred at the upper hook site. Distractive forces were monitored continuously by a strain gauge mounted on the tension side of the upper arm of the outrigger. The resulting data were compared among the various curvature groups. The relationship between the length of distraction and the maximum force produced was similar for all animals regardless of curvature. This relationship was quadratic and was characterized by an inflection point where forces increased rapidly with each distraction. The amount of distraction necessary to reach both the inflection and failure points differed only for curves above 100 degrees. The amount of force required to reach failure was lower for curves above 75 degrees. Curves above 50 degrees had a lower percent correction at the inflection point. Bending and tensile forces were calculated by vector analysis. Axial load efficiencies were greater for curves above 50 degrees, as evidenced by increased bending forces in these animals. The viscoelasticity of the spine decreased after inflection in all animals.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Electrical stimulation in the treatment of idiopathic scoliosis.
Sixty-two fully compliant patients (with 94 curves) met protocol criteria of 20 degree-39 degree curves, Risser iliac crest signs of 0, 1, or 2, and no prior treatment. Both clinical and roentgenographic examinations were performed before, during, and after treatment. The follow-up periods averaged 2.3 years, with a 3.2-year average follow-up period for patients who completed, rather than failed, Electro Spinal Orthosis (ESO) treatment. Seventy-one percent of the 20 degree-29 degree curves and 66% of the 30 degree-39 degree curves had progressed 5 degrees or more at follow-up evaluation. Fifty percent of the patients had a follow-up curve of at least 40 degrees or were treated by posterior spinal fusion and were considered treatment failures. The curve progression paralleled that found in natural history studies, and the rate of failure exceeded that found in orthotic treatment studies.
Adolescent↗
The natural history of idiopathic scoliosis.
A clear understanding of the natural history of idiopathic scoliosis is essential for developing effective treatment. The current information on its natural history indicates that a large number of patients have minor degrees of curvature (approximately 100 per 1000 individuals), although only about two per 1000 individuals warrant treatment because of curve progression. A large number of these curves do not increase even without treatment. Prognostic indicators such as growth, menarch, Risser sign, age at diagnosis, and sex are useful for predicting curve progression but are not always precise. Nonpredictive factors include family history, thoracic kyphosis, lumbar lordosis, lumbosacral transitional anomalies, and trunk balance. Future growth potential and curve severity remain the most reliable considerations in predicting the course of the disorder and in devising suitable approaches to treatment.
Adolescent↗
Scoliosis and pregnancy.
The effects of pregnancy on patients who have idiopathic scoliosis were investigated in terms of increased risk of progression of the curve. The charts, radiographs, and other pertinent data on 355 affected women who had reached skeletal maturity (Risser Grade 4) before 1975 were reviewed and analyzed. One hundred and seventy-five patients had had at least one pregnancy each (Group A) and 180 patients had never been pregnant (Group B). The groups were comparable with regard to the treatments that they had received. After skeletal maturity was reached, the curve progressed more than 5 degrees in 25 per cent and more than 10 degrees in 10 per cent of the patients in each group. The age of the patient at the time of the first pregnancy did not influence the risk of progression, and the stability of the curve before pregnancy did not decrease the risk of its progression during pregnancy. In patients who had had a spinal fusion, progression in the unfused portion of the spine was negligible in both Group A and Group B. The presence of a pseudarthrosis did not result in progression of the curve during pregnancy. The effects of scoliosis on pregnancy and delivery were evaluated in the 175 women in Group A. No specific problems that were directly related to the scoliosis were noted except for four patients, in whom delivery posed difficulties. The incidence of cesarean section was one-half of the national average, and no sections were directly related to the mother's scoliosis.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Influence of the Wilmington brace on spinal decompensation in adolescent idiopathic scoliosis.
The Wilmington brace is a custom-molded thoracolumbosacral orthosis for decompensated adolescent idiopathic curves. Using the roentgenographic measurement of Rudicel and Renshaw, 71 patients with pretreatment curves that were decompensated greater than 1.0 cm were investigated in detail. The average follow-up period was two years. There was no correlation between pretreatment Cobb angle and the magnitude of spinal decompensation. Pretreatment decompensation averaged 1.9 cm for 22 thoracic curves, 2.5 cm for 32 thoracolumbar-lumbar curves, and 2.4 cm for 17 double-structural curves. Overall, decompensation was improved in 50 patients (70%). Improvement in spinal decompensation averaged 1.4 cm for thoracic, 1.4 cm for thoracolumbar-lumbar, and 1.5 cm for double-structural curves, with decompensation in 27 patients (38%) measuring less than 1.0 cm at follow-up evaluation. An increase in spinal decompensation, averaging 1.2 cm, was found in 6% (one thoracic, two thoraco-lumbar-lumbar, and one double-structural curve). Spinal compensation is favorably influenced in the majority of patients treated with Wilmington brace for adolescent idiopathic scoliosis.
Adolescent↗
Effects of halothane on intraoperative scalp-recorded somatosensory evoked potentials to posterior tibial nerve stimulation in man.
Somatosensory evoked potentials (SEPs) were monitored in 116 patients receiving halothane anesthesia during spinal fusion surgery. Whereas it has been generally assumed that the use of halogenated inhalational anesthetics should be avoided with SEP monitoring because of their purported deleterious effects on scalp-recorded sensory responses, we found that reproducible SEPs were obtained throughout the surgical procedure in 91% of the cases we monitored while using halothane at concentrations of 0.25-2.0%. In those cases in which halothane was delivered continuously at 0.5%, reproducible evoked responses were recorded in 96% (75 of 78) of the patients. Our data demonstrated 3 major effects of halothane on the SEP: (a) a small but significant decrease in the average amplitude of the first two components (N25 and P30), (b) a significant increase in the average latency of the late positive component (P53) of the wave form, and (c) occasional obliteration of components N25, N40, P53, and N71, but never of P30. These effects did not, in most cases, interfere with our ability to obtain clinically useful recordings. Our results suggest that in many instances the use of halothane anesthesia can be combined successfully with the recording of intraoperative SEPs.
Electric Stimulation↗
Spinal deformity.
Spinal deformity is a relatively common disorder, particularly in teenage girls. Early detection is possible by a simple, quick visual inspection that should be a standard part of the routine examination of all preteen and teenage patients. Follow-up observation will reveal those curvatures that are progressive and permit orthotic treatment to prevent further increase in the deformity. Spinal fusion offers correction and stabilization of more severe degrees of scoliosis.
Adolescent↗
The natural history of idiopathic scoliosis before skeletal maturity.
A retrospective review of 326 female patients with untreated idiopathic scoliosis was performed to determine what factors might be useful in predicting the risk of curve progression. Components such as family history, height-weight ratio, lumbosacral transitional anomalies, kyphosis, lordosis, and trunk balance were not found to be significant. Predictive indicators included gender, curve patterns, and severity and growth potential.
Adolescent↗
Orthopaedic aspects of the VATER association.
The cases of twenty-eight patients with the VATER association, which consists of various combinations of vertebral anomalies, anal atresia, tracheoesophageal fistula with esophageal atresia, radial dysplasia, and renal anomalies, were reviewed. Associated anomalies included deformities of the ribs and lower limbs, a two-artery umbilical cord, a congenital heart defect, and auricular deformities. Three children died in the first two years of life. Of the remaining twenty-five patients, twelve have required a total of seventeen orthopaedic procedures for the treatment of congenital scoliosis or deformity of the upper or lower extremities.
Abnormalities, Multiple↗
Treatment of idiopathic scoliosis with the Wilmington brace. Results in patients with a twenty to thirty-nine-degree curve.
The results in seventy-nine adolescent patients (ninety-five curves) who had idiopathic scoliosis treated with the Wilmington brace are reported. The average follow-up was two years and six months (range, one to nine years). Before treatment, all of the patients had a curve that measured 20 to 39 degrees and a Risser sign of zero or 1. Although the magnitude of the curve was generally reduced by about 50 per cent with the initial application of the brace, a gradual loss of this initial improvement was observed both during active treatment and after the patient was weaned from the brace. Although twenty-seven (28 per cent) of the curves had progressed more than 5 degrees at follow-up, Lonstein and Carlson reported that the projected probability of progression of untreated 20 to 29-degree curves is 68 per cent. Thirty-six per cent of the thoracic curves, 16 per cent of the thoracolumbar and lumbar curves, and 28 per cent of the double major curves had progression of more than 5 degrees. However, only 11 per cent of the patients had a curve that progressed sufficiently to warrant fusion. Our findings indicate that the Wilmington brace favorably alters the natural history of 20 to 39-degree idiopathic curves.
Adolescent↗
Nonoperative treatment of spinal deformity: the case for observation.
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Adolescent↗
Chest roentgenograms and scoliosis.
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Female↗