Standardization of Cardiopulmonary Roentgenograms in Infants and Children

Methods were devised to standardize cardiopulmonary radiographs of infants and children. With these techniques, films can be taken either at the end of inspiration and in systole, or at the end of inspiration alone. A statistical evaluation of these two methods demonstrated their superiority over the usual procedure. The use of these techniques is strongly recommended in patients of the pediatric age group.     

Occult posterolateral rotatory dislocation of the elbow with olecranon fracture in a child: a case report

ABSTRACT: INTRODUCTION: Acute posterolateral rotator elbow dislocation in a child is rare and can be easily misdiagnosed due to immaturity of the epiphysis. This is the first case of occult posterolateral rotator elbow dislocation in combination with an olecranon fracture. We report our experience with this case, which was not diagnosed correctly by plain radiographs. CASE PRESENTATION: An 11-year-old Asian boy suffered severe pain and swelling of his right elbow after his outstretched arm hit a car dashboard in a motor vehicle accident. Plain radiographs showed only a minimally displaced olecranon fracture and a tiny lateral epicondylar avulsion fracture. However, stress radiographs under general anesthesia revealed severe posterolateral rotatory instability. During surgery, we found that the cartilaginous lateral epicondylar apophysis was much larger than the epicondylar fragment on the radiographs. After the lateral epicondylar osteochondral fragment and lateral collateral ligament complex were fixed, the instability disappeared. CONCLUSION: Our experience with this case shows that it is important to check for instability with pediatric elbow fractures, because a tiny avulsion fracture was able to cause severe posterolateral rotatory instability in a child.     

Radiographic analysis of growth in pediatric microsurgical toe-to-hand transfers

Microsurgical toe-to-hand transfers may provide improved hand function in children with absent digits. To date, documentation of the growth potential of these transferred digits has not been performed. This study reviewed the authors' series of pediatric toe-to-hand transfers, with specific attention paid to measuring growth by radiographic analysis. From 1995 to 2000, 23 toe-to-hand transfers were performed in 18 children. Age at time of transfer ranged from 2.8 to 13 years. Indications included constriction band syndrome, transverse deficiency, longitudinal deficiency, traumatic amputation, and vascular malformation. The transfers were successful in 22 of 23 procedures (96 percent success rate). Radiographic analysis of growth was performed using three criteria: (1) appearance of open epiphyseal plates, (2) comparison with preoperative radiographs, and (3) comparison with radiographs of the contralateral control toe. Epiphyseal plates remained open on postoperative radiographs in 27 of 28 phalanges (96 percent) at a mean of 12 months' follow-up (range, 1 to 36 months). The preoperative foot radiographs were compared with serial radiographs of the transferred toe over time. In 10 toe transfers with follow-up greater than 6 months (mean, 21 months), nine patients had increased bony length in the transferred digit. In four patients, radiographs of the toe transfer were compared with radiographs of the corresponding toe on the opposite foot. With a mean follow-up of 29 months, all patients had equal length measurements of the toe transfer with the contralateral toe control. These data provide objective evidence that digital growth potential is preserved in toe-to-hand transfers. Furthermore, this bone growth is comparable with that of the corresponding toe on the contralateral foot. Therefore, microsurgical toe-to-hand transfers may provide children with extra digits that maintain growth and improve hand function.     

Prosthetic hip failure: retrospective radiograph image analysis of the acetabular cup

A method has been developed for quantifying movement and wear of the acetabular component (cup) of total hip replacements (THR) from routine postoperative and review radiographs. The method uses both interactive and automatic computer image analysis techniques. Dimensions of the prosthesis are used to scale the measurements and so overcom variation in radiographic alignment. The application of the method is illustrated by retrospective investigations of cup migration and wear using review radiographs taken over a follow-up of at least 12 years.     

Bronchiectasis in acute leukaemia.

Five children in remission from acute lymphoblastic leukaemia developed bronchiectasis when on chemotherapy. Persistent collapse or consolidation on chest radiographs was helpful in suggesting the diagnosis. Necropsy established the diagnosis in one child who died of massive haemoptysis when in complete remission, and bronchography confirmed the diagnosis in three. In a further child the diagnosis was based on clinical and chest X-ray findings alone. The surviving children were treated with prophylactic rotating antibiotics. Routine chest radiographs are recommended in children with acute lymphoblastic leukaemia, as bronchiectasis may otherwise be underdiagnosed.     

Tools for high tibial wedge osteotomy

Surgical instruments are described which have been developed for use in high tibial wedge osteotomy. This operation is a treatment for degenerative arthritis of the knee in which one compartment of the joint is predominantly affected resulting in a deformity. Realignment of the bones alters the load distribution on the joint which can relieve pain. Tools have been designed to facilitate the removal of a wedge of bone cut at a precise angle calculated from load bearing radiographs. The tools are a marker pin guide and a saw guide; their use has resulted in accurate bone realignment confirmed by postoperative radiographs.     

PA-CRM: A continuous reassessment method for pediatric phase I oncology trials with concurrent adult trials

Pediatric phase I trials are usually carried out after the adult trial testing the same agent has started, but not completed yet. As the pediatric trial progresses, in light of the accrued interim data from the concurrent adult trial, the pediatric protocol often is amended to modify the original pediatric dose escalation design. In practice, this is done frequently in an ad hoc way, interrupting patient accrual and slowing down the trial. We developed a pediatric-continuous reassessment method (PA-CRM) to streamline this process, providing a more efficient and rigorous method to find the maximum tolerated dose for pediatric phase I oncology trials. We use a discounted joint likelihood of the adult and pediatric data, with a discount parameter controlling information borrowing between pediatric and adult trials. According to the interim adult and pediatric data, the discount parameter is adaptively updated using the Bayesian model averaging method. Numerical study shows that the PA-CRM improves the efficiency and accuracy of the pediatric trial and is robust to various model assumptions.     

Pediatric cataracts

Congenital and acquired pediatric cataracts are recognized by many as being among the visually devastating pathologies of children. They remain one of the leading causes of legal blindness for children in under developed countries world wide. Diagnosed in approximately 400–500 patients per year in the United States alone, their presence requires agressive management with concurrent amblyopia therapy. Although most pediatric opacities are idiopathic, systemic etiologies which include genetic inheritance (Fabry's disease, Lowe's syndrome, Conradi's syndrome) metabolic disturbances (Galactosemia, Hypocalcemia, hypoglycemia, retinitis pigmentosa), infectious diseases (maternal syphilis, varicella virus, herpes virus, cytomegalovirus), toxic substances and trauma must be investigated. We reviewed the literature for pertinent information on the differential diagnosis of congenital and acquired cataracts in the pediatric population. The modalities and techniques of the pediatric examination are presented along with a discussion of the maladies, most recent advances in surgical intervention, optical or contact lens correction and amblyopia therapy associated with pediatric cataracts.     

Antifungal Therapy in Pediatric Patients

Invasive fungal infections still play a major role in morbidity and mortality in pediatric patients, especially in children undergoing therapy for an underlying malignancy and in preterm infants. Relative to the adult population, pediatric age groups display important differences not only in host biology, predisposing conditions, epidemiology, and presentation of fungal infections, but also in the disposition and clearance of antifungal compounds. During the past decade, several new antifungal agents have been developed. Although not all of these agents are yet approved for children, the pediatric development of antifungal agents has moved forward in an exemplary manner, which is essential for the successful management of the individual patient. This article reviews the current data on pharmacokinetics, safety, and dosing of antifungal agents in pediatric patients.     

Medical Radiation to Children with Congenital Heart Disease

A retrospective analysis was made of the source of medical radiation received by 25 children who were investigated by cardiac catheterization techniques and followed in the Cardiac Outpatient Clinic of the Health Centre for Children, Vancouver General Hospital. The source of radiation was analyzed. The r dose per year received from plane films averaged 0.05 r, from cardiac fluoroscopy 6.7 r, and from catheterization and angiocardiography studies 1.58 r per year. In six of the 25 children, radiation doses to the thorax exceeded the LD₅₀ for adult humans. In these six patients 95.8% of the radiation received was during cardiac fluoroscopy. Routine fluoroscopy for the radiological re-evaluation of pediatric patients with congenital heart disease should be replaced by plain chest radiographs.     

Gonad protection in young orthopaedic patients.

OBJECTIVE--To determine whether gonad shields are correctly positioned on the pelvic radiographs of children with slipped capital femoral epiphysis. DESIGN--Retrospective study of radiographs taken of children treated by in situ pinning of slipped capital femoral epiphysis between 1 January 1983 and 31 December 1988. SETTING--Three teaching hospitals in north west England. PATIENTS--32 patients with complete set of radiographs. RESULTS--An average of 10.8 anteroposterior pelvic radiographs plus 8.9 lateral hip radiographs had been performed per patient. Gonad shields had been completely omitted in 137 (40%) anteroposterior pelvic radiographs performed on the 32 patients at the time of completion of the study. In 100 (29%) the gonad shields were adequately protecting the gonads, but in 109 (31%) the gonad shields were not protecting the gonads due to incorrect positioning of the shield. The incorrect positioning of the gonad shields was more commonly found in girls than boys (64 vs 45; p less than 0.012), presumably because of the difficulty in determining gonadal position in relation to surface landmarks. Absence of gonad shields was also more commonly seen in girls (82 v 55; p less than 0.005), but this is not easily explained. CONCLUSIONS--Gonad shields are not protecting the gonads in a large percentage of anteroposterior pelvic radiographs (71%) because they have been omitted or inadequately placed. This avoidable excess radiation exposure to the gonads, combined with the inability to shield the gonads in lateral hip radiographs and the large number of radiographs performed, results in the gonads receiving a higher dose of radiation than may otherwise be the case, and may increase the potential for disease in the future offspring of these patients.     

A computational technique to measure fracture callus in radiographs

Callus formation occurs in the presence of secondary bone healing and has relevance to the fracture's mechanical environment. An objective image processing algorithm was developed to standardize the quantitative measurement of periosteal callus area in plain radiographs of long bone fractures. Algorithm accuracy and sensitivity were evaluated using surrogate models. For algorithm validation, callus formation on clinical radiographs was measured manually by orthopaedic surgeons and compared to non-clinicians using the algorithm. The algorithm measured the projected area of surrogate calluses with less than 5% error. However, error will increase when analyzing very small areas of callus and when using radiographs with low image resolution (i.e. 100 pixels per inch). The callus size extracted by the algorithm correlated well to the callus size outlined by the surgeons (R²=0.94, p<0.001). Furthermore, compared to clinician results, the algorithm yielded results with five times less inter-observer variance. This computational technique provides a reliable and efficient method to quantify secondary bone healing response.     

Relationships between spinal landmarks and skin surface markers

This investigation determined relationships between coronal vertical alignment (CVA) and sagittal vertical alignment (SVA) variables calculated from radiographs and surface markers representing bony landmarks. Biplanar radiographs were taken on 28 subjects (standing) after 2 metallic surface markers were placed on the skin superficial to C7 and S2. The CVA-R and SVA-R were measured on the radiographs. Similar variables were calculated from the surface markers (CVA-P-R, SVA-P-R). Correlation between CVA-R and CVA-P-R was 0.894 (p<0.000), and between SVA-R and SVA-P-R was 0.946 (p<0.000). Results lead to three recommendations: (1) obtain surface marker data when radiographs are taken to establish relationships between the two sets of data, (2) take care in providing instructions to the subjects if measures are to be taken at different times, and (3) observe caution in interpreting results when simultaneous x-ray and surface marker data were not recorded.     

Quantitative quality assurance in a community hospital pediatric intensive care unit.

Unbiased, objective evaluations of quality of care are preferred over subjective evaluations. We observed 681 admissions to a pediatric intensive care unit of a community hospital from 1989 through 1990 for outcomes and physiologic profiles of the patients on the admission day using the Pediatric Risk of Mortality score to assess severity of illness. Mortality adjusted for severity of illness was compared with that predicted from a pediatric intensive care unit of a tertiary medical center: 32.6 deaths were predicted based on the physiologic profiles, and 23 occurred. The number of outcomes and their distribution according to mortality risk indicated close agreement between observed and predicted results. Thus, a quality-assurance technique developed in tertiary care centers can be used to indicate a comparable level of care in a community hospital.     

Comparing Reference Charts

Reference charts are valuable tools for clinicians in their daily work on pediatric clinics. Reference charts are often constructed by smoothing techniques, and in this paper we present a newly developed non-parametric test for comparing these charts. We illustrate the method by an example. The worked example compares cross-sectional data on height in children from two Danish studies from 1970 and 1990, respectively. The test compares the average height over the range of ages for the two groups.     

Metacarpophalangeal pattern profile analysis in clinical genetics: an applied anthropometric method

The hand is a complex anatomical structure with the component bones susceptible to a combination of environmental and genetic factors that may affect the bone length and width. The alterations may involve a single bone or specific group of bones. The metacarpophalangeal pattern profile (MCPP) developed by Poznanski, Garn, and others (Poznanski et al. Birth Defects VIII (5): 125-131, 1972) is a graphic representation of the relative lengthening and shortening of the 19 tubular bones of the hand useful for diagnosis, comparison of dissimilar patients, and gene carrier detection. The profile hand bone measurements are derived from posteroanterior hand radiographs and are standardized for age and sex. Specific profiles have been developed for several syndromes. Therefore, MCPP analysis has developed from a method of describing changes in the hand to a technique useful in assigning a diagnosis to a specific syndrome and evaluation of skeletal development. The current status of MCPP analysis in clinical genetics, particularly with the Prader-Labhart-Willi and Sotos syndromes, is discussed.     

Computational simulations of flow dynamics and blood damage through a bileaflet mechanical heart valve scaled to pediatric size and flow

Despite pressing needs, there are currently no FDA approved prosthetic valves available for use in the pediatric population. This study is performed for predictive assessment of blood damage in bileaflet mechanical heart valves (BMHVs) with pediatric sizing and flow conditions. A model of an adult-sized 23 mm St. Jude Medical (SJM) Regent^™ valve is selected for use in simulations, which is scaled in size for a 5-year old child and 6-month old infant. A previously validated lattice-Boltzmann method (LBM) is used to simulate pulsatile flow with thousands of suspended platelets for cases of adult, child, and infant BMHV flows. Adult BMHV flows demonstrate more disorganized small-scale flow features, but pediatric flows are associated with higher fluid shear stresses. Platelet damage in the pediatric cases is higher than in adult flow, highlighting thrombus complication dangers of pediatric BMHV flows. This does not necessarily suggest clinically important differences in thromboembolic potential. Highly damaged platelets in pediatric flows are primarily found far downstream of the valve, as there is less flow recirculation in pediatric flows. In addition, damage levels are well below expected thresholds for platelet activation. The extent of differences here documented between the pediatric and adult cases is of concern, demanding particular attention when pediatric valves are designed and manufactured. However, the differences between the pediatric and adult cases are not such that development of pediatric sized valves is untenable. This study may push for eventual approval of prosthetic valves resized for the pediatric population. Further studies will be necessary to determine the validity and potential thrombotic and clinical implications of these findings.     

Finite element model development of a child pelvis with optimization-based material identification

A finite element (FE) model of a 10-years-old child pelvis was developed and validated against experimental data from lateral impacts of pediatric pelves. The pelvic bone geometry was reconstructed from a set of computed tomography images, and a hexahedral mesh was generated using a new octree-based hexahedral meshing technique. Lateral impacts to the greater trochanter and iliac wing of the seated pelvis were simulated. Sensitivity analysis was conducted to identify material parameters that substantially affected the model response. An optimization-based material identification method was developed to obtain the most favorable material property set by minimizing differences in biomechanical responses between experimental and simulation results. This study represents a pilot effort in the development and validation of age-dependent musculoskeletal FE models for children, which may ultimately serve to evaluate injury mechanisms and means of protection for the pediatric population.     

Digital automated RSA compared to manually operated RSA

The accuracy of digital Roentgen stereophotogrammetric analysis (RSA) was compared to the accuracy of a manually operated RSA system. For this purpose, we used radiographs of a phantom and radiographs of patients. The radiographs of the patients consisted of double examinations of 12 patients that had a tibial osteotomy and of double examinations of 12 patients that received a total hip prosthesis. First, the radiographs were measured manually with an accurate measurement table. Subsequently, the images were digitized by a film scanner at 150 DPI and 300 DPI resolutions and analyzed with the RSA-CMS software. In the phantom experiment, the manually operated system produced significantly better results than the digital system, although the maximum difference between the median values of the manually operated system and the digital system was as low as 0.013 mm for translations and 0.033° for rotations. In the radiographs of the patients, the manually operated system and the digital system produced equally accurate results: no significant differences in translations and rotations were found. We conclude that digital RSA is an accurate, fast, and user friendly alternative for manually operated RSA. Currently, digital RSA systems are being used in a growing number of clinical RSA-studies.