CT detection of basal ganglion lesions in neurofibromatosis type 1: correlation with MRI

Summary Prospective study of CT and MRI in 41 consecutive children with suspected type 1 neurofibromatosis revealed basal ganglion lesions on T2-weighted spin echo images in 22 cases (54%) and on CT in only 7 of those (32%). T2-weighted spin-echo MRI also revealed multiple signal changes in the supra- and infratentorial white matter and brain stem that went completely unnoticed on CT.     

Forces and moments on the human leg in the frontal plane during static bipedal stance.

An experimental apparatus was assembled that permitted measurement of the vertical and lateral ground reaction forces as the hip is abducted, resulting in foot separations ranging from 0.25 to 71 cm, with the knee in 0 degree flexion. Twelve healthy volunteers (8 men and 4 women) were tested. The hip joint was located by means of center of rotation measurements on each subject's legs, and the location of the knee joint was determined using anatomical measurements. It was observed that the mediolateral force was nonzero and directed toward the body midline, even when the subject's feet were placed together. With the feet placed at shoulder width, the population mean mediolateral force was 3% of body weight. It was determined that simplifying assumptions based upon either "zero lateral force," or "zero hip moment," produced errors, when compared with our measured values, over various ranges of foot separation, with the zero hip moment assumption providing accuracy over a broader range. The inclination of the tibial plateau, with respect to the long axis of the tibia, that would produce minimal mediolateral shear at the knee is presented. Research and clinical applications of our results and techniques are discussed.     

Agenesis of the vermis with fusion of the cerebellar hemispheres,septo-optic dysplasia and associated anomalies

Summary Agenesis of the cerebellar vermis with fusion of the dentate nuclei and cerebellar hemispheres (rhombencephalosynapsis) is a rare cerebral malformation. We report the case of a 7-h-old girl whose mother had taken the drug phencyclidine during the first 6 weeks of pregnancy. Absence of the septum pellucidum, hypoplasia of the commissural system, optic nerves, chiasm and tracts, moderate hydrocephalus, and agenesis of the posterior lobe of the pituitary were also found. Extracranial congenital anomalies involved the cardiovascular, respiratory, urinary, and musculoskeletal systems. Death was secondary to severe respiratory distress and bradycardia. The literature concerning this rare form of cerebellar malformation is reviewed.     

Clinical impact of intestinal neuronal malformations: a prospective study in 141 patients

A prospective study of 141 consecutive patients with intestinal neuronal malformations is presented. The single malformation of the autonomic nervous system that always required surgical intervention was aganglionosis. Giant ganglia, reduced parasympathetic tone, immature ganglia, and hypogenetic or heterotopic nerve cells were seen in all forms of malformations. However, the incidence in specific malformations was variable. Multiple giant ganglia were identified in all patients with intestinal neuronal dysplasia (IND) type B, but also in various other malformations. Heterotopic nerve cells in the myenteric plexus were seen in the proximal segment of 15 of 74 patients (20.3%) with aganglionosis and 5 of 9 patients (55.6%) with hypoganglionosis. A significant impact on symptoms was found for IND type B: 34 (45.9%) of 74 children with aganglionosis had associated IND type B, and these children more frequently developed ileus (P < 0.001) and more often needed a second resection (P < 0.05) compared to those with isolated aganglionosis. This indicates an additive effect of both malformations, and therefore, in these patients an extended resection should be carried out.Twelve of 67 patients (17.9%) without aganglionosis needed resection for untreatable constipation. This included 7 of 9 children with hypoganglionosis, both patients with heterotopia of the myenteric plexus, 1 of 20 with isolated IND type B, and 2 of 12 with reduced parasympathetic tone. None of the patients with immaturity, heterotopia of the submucous plexus, or mild dysganglionosis required surgery. Six children (8.9%) without aganglionosis underwent sphincteromyotomy and 2 with IND type B had a temporary colostomy. At follow-up (mean 2.4 ± 1.4 years), the outcome in patients with resected aganglionosis was better than in patients who had resections for other malformations; 49 (69%) of 71 patients with aganglionosis were asymptomatic compared to 4 (33.3%) of 12 with other malformations (P < 0.05). It is concluded that some intestinal malformations have a relevant clinical impact. However, the severity of symptoms in the individual patient may not be explained by specific histochemical findings from a limited number of mucosal biopsies. The pathognomonic histochemical criteria of isolated IND typeB — immaturity, reduced parasympathetic tone, heterotopia of the submucous plexus, and mild dysganglionosis —rarely require surgical therapy and should be treated conservatively.     

The Histology of the Lung in Neonates with Tricuspid Valve Disease and Gross Cardiomegaly Due to Severe Regurgitation

Lung autopsies from four neonates with Ebstein's anomaly or tricuspid valve dysplasia and gross cardiomegaly were examined. The mean cardiothoracic ratio was 92 ± 0.5%. The degrees of pulmonary hypoplasia and pulmonary artery muscularization were assessed and were compared with those in lungs from four controls and four patients with diaphragmatic hernias. Lung and body weight ratios and radial alveolar counts, which reflect pulmonary hypoplasia and immaturity, were significantly decreased only in patients with diaphragmatic hernia. The thickness of the medial muscle layer in small pulmonary arteries was greater in patients with diaphragmatic hernia; however, in patients with tricuspid valve disease, it was relatively small. Abnormal vascular muscle extension was seen only in patients with diaphragmatic hernia. In the cases of tricuspid valve disease, although cardiomegaly and lung compression were severe, lung hypoplasia and immaturity were not, and neither abnormal medial thickening nor extension were found. Our results suggest that, at least in full-term infants with tricuspid valve disease, surgical relief of lung compression may improve respiratory function, even if the cardiomegaly is severe.     

Effect of Dexamethasone Therapy on the Neonatal Ductus Arteriosus

Patent ductus arteriosus (PDA) is believed to be a contributing factor in the etiopathogenesis of bronchopulmonary dysplasia (BPD). We studied the effects of early dexamethasone therapy on persistent ductal patency and the role of PDA in the etiopathogenesis of BPD during the course of a randomized double-blind trial of dexamethasone to prevent BPD. Infants, who weighed between 700 and 999 g, had severe RDS, and had been given surfactant, were randomized to receive a 12-day course of dexamethasone (n= 13) or placebo (n= 17) starting within the first 12 hours of postnatal life. The diagnosis of PDA was made clinically and was confirmed by cardiac ultrasound. The incidence of clinically significant ductus in infants who weighed less than 1000 g was 23% in the dexamethasone-treated group, as compared with 59% in infants who were given placebo. This difference was marginally significant, p= 0.05, odds ratio 0.21, 95% confidence interval 0.04–1.05. None of the infants in the dexamethasone group had recurrence of PDA after indomethacin therapy as compared with three infants in the placebo group. Dexamethasone significantly reduced the number of days infants required ventilator and supplemental oxygen as compared with infants who received placebo. Dexamethasone, as compared with placebo, also reduced the incidence of BPD, p= 0.025, odds ratio 0.08, 95% confidence interval 0.01–0.58. Dexamethasone may reduce the incidence of PDA in premature infants who weigh less than 1000 g at birth and thereby reduce the incidence of BPD.     

Do the hamstrings and adductors contribute to excessive internal rotation of the hip in persons with cerebral palsy?

Children with cerebral palsy frequently walk with excessive internal rotation of the hip. Spastic medial hamstrings or adductors are presumed to contribute to the excessive internal rotation in some patients; however, the capacity of these muscles to produce internal rotation during walking in individuals with cerebral palsy has not been adequately investigated. The purpose of this study was to determine the hip rotation moment arms of the medial hamstrings and adductors in persons who walk with a crouched, internally-rotated gait. Highly accurate computer models of three subjects with cerebral palsy were created from magnetic resonance images. These subject-specific models were used in conjunction with joint kinematics obtained from gait analysis to calculate the rotational moment arms of the muscles at body positions corresponding to each subject’s internally-rotated gait. Analysis of the models revealed that the medial hamstrings, adductor brevis, and gracilis had negligible or external rotation moment arms throughout the gait cycle in all three subjects. The adductor longus had an internal rotation moment arm in two of the subjects, but the moment arm was small (<4 mm) in each case. These findings indicate that neither the medial hamstrings nor the adductor brevis, adductor longus, or gracilis are likely to be important contributors to excessive internal rotation of the hip. This suggests that these muscles should not be lengthened to treat excessive internal rotation of the hip and that other factors are more likely to cause internally-rotated gait in these patients.     

A comparison of Rasch with Likert scoring to discriminate between patients' evaluations of total hip replacement surgery

The purpose of this study was to examine whether there are advantages in terms of outcome assessment of using Rasch methods of scoring the 12-item Oxford Hip Score (OHS) questionnaire over conventionally Likert scores. As part of a prospective cohort study of total hip replacements in five former regions of England the OHS was sent to patients pre-operatively, at 3 months and 1 year post-operatively. Post-operative data was collected on over 5000 cases. Based on the level of satisfaction with surgery, patients were divided into satisfied and dissatisfied. Analyses were performed to test the relative precision (RP) of Rasch scoring vs. conventionally Likert scores in discriminating the groups experiencing different level of satisfaction. Considerable gains in precision were achieved with Rasch scoring methods when groups were compared 3 and 12 months post-operatively. The results from the current study suggest that in some situations there may be substantial gains in measuring health related outcomes using Rasch-based scoring methods.     

生化检查对人工髋关节感染的诊断价值

目的评价翻修术前生化检查对人工髋关节感染的诊断价值。方法对145例人工髋关节翻修患者进行回顾性分析,分别以血沉(ESR)和C-反应蛋白(CRP)作为诊断标准对人工髋关节感染进行诊断,并与“金标准”的诊断结果进行比较分析。结果血沉和CRP诊断人工髋关节感染的灵敏度分别为57.89%、68.42%,特异度分别为85.71%、88.89%,阳性预测值分别为37.93%、48.15%,阴性预测值分别为93.10%、94.92%,准确度分别为20.00、18.62,Youden指数分别为0.44、0.57。结论血沉和CRP作为人工髋关节翻修术前的常规检查,对人工髋关节感染的诊断具有筛选价值;两者结合起互补作用,可以增加诊断的准确性。