Cumulative exposure to medical radiation for children requiring surgery for congenital heart disease

OBJECTIVE

To describe cumulative radiation exposure in a large single-center cohort of children with congenital heart disease (CHD) and identify risk factors for greater exposure.

STUDY DESIGN

A detailed medical radiation exposure history was collected retrospectively for patients aged <18 years who underwent surgery for CHD between January 1, 2001, and July 22, 2009. Cumulative per patient exposure was quantified as the effective dose in millisieverts (mSv) and annualized (mSv/year).

RESULTS

A total of 4132 patients were subjected to 134,715 radiation examinations at a median follow-up of 4.3 years (range, 0-8.6 years). Exposure clustered around the time of surgery. The median exposure was 14 radiologic tests (the majority of which were plain film radiographs) at an effective dose of 0.96 mSv (the majority of which was from cardiac catheterization), although this distribution had a very wide range. Almost three-quarters (73.7%) were exposed to <3 mSv/year, and 5.3% were exposed to >20 mSv/year. Neonates, children with genetic syndromes, and children requiring surgery for cardiomyopathy, pulmonary valve, single ventricle, or tricuspid valve diseases were more likely to have higher exposure levels, and those requiring surgery for aortic arch anomalies or atrioventricular septal defects were more likely to have lower levels.

CONCLUSION

Children with CHD requiring surgery are exposed to numerous medical forms of ionizing radiation. Although the majority of patients receive <3 mSv/year, there are identifiable risk factors for higher exposure levels. This may have important health implications as these patients age.

Variability in the interpretation of chest radiographs for the diagnosis of pneumonia in children

BACKGROUND

Although chest radiography is commonly used to establish the diagnosis of pneumonia in children, the reliability of radiographic findings among radiologists is not well described.

OBJECTIVE

We sought to evaluate the inter-rater and intra-rater reliability of radiographic features commonly described by radiologists in childhood pneumonia.

METHODS

Prospective case-based study. One hundred and ten radiographs of children evaluated in a pediatric emergency department for suspicion of pneumonia were interpreted by six radiologists at two academic children's hospitals. Radiologists were blinded to the clinical history. Reliability of standardized radiographic features was evaluated using the kappa statistic.

RESULTS

The radiographic finding of an alveolar infiltrate demonstrated substantial reliability among radiologists (κ = 0.69). The presence of 'any infiltrate' and pleural effusion demonstrated moderate reliability (κ = 0.47 and k=0.45, respectively). Other radiographic features were less reliable: air bronchograms (κ = 0.32), hilar adenopathy (κ = 0.21), and interstitial infiltrate (κ = 0.14). Similarly, the finding of alveolar infiltrate demonstrated substantial intra-rater reliability upon review of ten duplicate radiographs, whereas interstitial infiltrate was less reliable.

CONCLUSION

The radiographic finding of an alveolar infiltrate is very reliable among pediatric radiologists, whereas the finding of an interstitial infiltrate is less reliable.

Correlates of HIV-1 viral suppression in a cohort of HIV-positive drug users receiving antiretroviral therapy in Hanoi, Vietnam

Injection drug users bear the burden of HIV in Vietnam and are a focus of national treatment programmes. To date, determinants of successful therapy in this population are unknown. Substance use and clinical correlates of viral suppression were studied in 100 HIV-1-infected drug users receiving antiretroviral therapy (ART) for at least six months in Hanoi, Vietnam. The mean age of the cohort was 29.9 + 4.9 years; all were men. A majority of patients (73%) achieved viral suppression (HIV-RNA <1000 copies/mL). Correlates of viral suppression include self-reported > or = 95% adherence (P < 0.01) and current use of trimethoprim/sulphamethoxazole (P < 0.01); current or ever diagnosed with tuberculosis was associated with viral non-suppression (P = 0.006). Tobacco use was prevalent (84%), and surprisingly 48% of patients reported active drug use; neither was associated with viral non-suppression. This is the first study to document successful ART treatment in a population of Vietnamese drug users; rates of viral suppression are comparable to other international populations. The 28% of patients without HIV-1 suppression highlight the need for adherence promotion, risk reduction programmes, and population-based surveillance strategies for assessing the emergence of HIV drug resistance in settings where access to viral load and drug resistance testing is limited.

Alcohol use among HIV-infected persons in care: results of a multi-site survey

OBJECTIVE

We sought to determine the prevalence of any alcohol use and hazardous alcohol consumption among HIV-infected individuals engaged in care and to identify factors associated with hazardous alcohol use.

METHODS

During 2003, 951 patients were interviewed at 14 HIV primary care sites in the USA. Hazardous drinking was defined as >14 drinks/week or >or=5 drinks/occasion for men and >7 drinks/week or >or=4 drinks/occasion for women. Moderate alcohol use was consumption at less than hazardous levels. We used logistic regression to identify factors associated with any alcohol use and hazardous alcohol use.

RESULTS

Forty per cent of the sample reported any alcohol use in the 4 weeks prior to the interview; 11% reported hazardous use. In multivariate regression, male sex [adjusted odds ratio (AOR) 1.52 (95% confidence interval, CI, 1.07-2.16)], a college education (compared to<high school) [AOR 1.87 (1.10-3.18)] and illicit drug use [AOR 2.69 (1.82-3.95)] were associated positively with any alcohol use, while CD4 nadir >or=500 cells/microL [AOR 2.65 (1.23-5.69)] and illicit drug use [AOR 2.67 (1.48-4.82)] were associated with increased odds of hazardous alcohol use (compared to moderate and none).

CONCLUSIONS

Alcohol use is prevalent among HIV-infected individuals and is associated with a variety of socioeconomic and demographic characteristics. Screening for alcohol use should be routine practice in HIV primary care settings.

A prospective observational study of IVC filters in pediatric patients

BACKGROUND

The use of inferior vena cava (IVC) filters to prevent pulmonary embolism (PE) has increased with the advent of retrievable filters (Crowther: Am J Med 120: S13-S17, 2007). Both permanent and retrievable filters have been used in the pediatric population, though reports describing such patients and their outcomes are limited.

PROCEDURE

Our center has established a longitudinal prospective cohort study of consecutive patients with acute venous thromboembolism (VTE) at our pediatric tertiary care institution. Data collection in this study includes medical history, risk factors, radiologic and laboratory studies, therapy, and follow-up.

RESULTS

Two hundred ten patients were enrolled into this cohort from January 2003 to January 2007. IVC filters were percutaneously placed into 11 patients, ranging in age from 6.8 to 23.4 years. The primary reason for filter placement was a VTE and a contraindication to anticoagulation. Nine patients had retrievable filters placed and two received permanent filters. Seven of the nine retrievable filters were removed 21-97 days (median 37 days) after placement. In the remaining two patients, thrombus prevented removal in one, and the filter was electively retained in the other. One patient with a permanent filter died from malignancy. The three patients who are alive and well with IVC filters have had them for 25-60 months. No patient with an IVC filter developed a subsequent PE.

CONCLUSIONS

Approximately 5% of patients in this pediatric thrombosis cohort received an IVC filter. The placement and removal of these devices is technically feasible in children.

The impact of illicit drug use and substance abuse treatment on adherence to HAART

High levels of adherence to highly active antiretroviral therapy (HAART) are essential for virologic suppression and longer survival in patients with HIV. We examined the effects of substance abuse treatment, current versus former substance use, and hazardous/binge drinking on adherence to HAART. During 2003, 659 HIV patients on HAART in primary care were interviewed. Adherence was defined as > or =95% adherence to all antiretroviral medications. Current substance users used illicit drugs and/or hazardous/binge drinking within the past six months, while former users had not used substances for at least six months. Logistic regression analyses of adherence to HAART included demographic, clinical and substance abuse variables. Sixty-seven percent of the sample reported 95% adherence or greater. However, current users (60%) were significantly less likely to be adherent than former (68%) or never users (77%). In multivariate analysis, former users in substance abuse treatment were as adherent to HAART as never users (Adjusted Odds Ratio (AOR)=0.82; p>0.5). In contrast, former users who had not received recent substance abuse treatment were significantly less adherent than never users (AOR=0.61; p=0.05). Current substance users were significantly less adherent than never users, regardless of substance abuse treatment (p<0.01). Substance abuse treatment interacts with current versus former drug use status to affect adherence to HAART. Substance abuse treatment may improve HAART adherence for former substance users.

Peri-infarct ischemia determined by cardiovascular magnetic resonance evaluation of myocardial viability and stress perfusion predicts future cardiovascular events in patients with severe ischemic cardiomyopathy

BACKGROUND

We assessed whether cardiovascular magnetic resonance imaging (CMR) of peri-infarct ischemia provides prognostic information in severe ischemic cardiomyopathy (ICM) patients referred for revascularization.

METHODS

Twenty-one patients with severe ICM were recruited prospectively for combined stress adenosine perfusion, late gadolinium enhancement, and rest perfusion studies. The patients were followed for in-hospital and post-discharge cardiovascular events.

RESULTS

During 12+/- 9.8 months follow-up, 67% of the patients with peri-infarct ischemia and 13% of the patients without peri-infarct ischemia had cardiovascular events (p = 0.03). CONCLUSION. In severe ICM patients, the presence of peri-infarct ischemia was associated with a higher incidence of cardiovascular events.

Complications of non-endoscopic percutaneous laser disc decompression and nucleotomy with the neodymium: YAG laser 1064 nm

In this review, we discuss how nonendoscopic percutaneous laser disc decompression (PLDD) and nucleotomy, using the YAG laser 1064, now has reinforced itself as a minimally invasive procedure in discogenic, vertebral pain syndromes, created by bulging, protrusions, and contained and uncontained extrusions in all areas of the spine. The rate of complication is an important criterion of the application of this new method. 3377 patients were treated with this method in the period of November 11, 1989 to April 30, 2002. While 356 patients' cervical spine was operated on, a further 38 patients had their thoracic spine operated on. Six weeks later, a prospective, consecutive control followed with an uninterrupted recording. Subsequently, all complications that occurred in this time frame were recorded. A comparison was carried out between the complication rate as covered by the literature of other intradiscal percutaneous methods and open disc surgery. Using the Nd-YAG laser 1064 nm, PLDD is generally evaluated with a complication rate of 0.5%. In the cervical spine area, the complication rate was 1.0%. No significant complications followed the thoracic intervention. In comparison to figures suggested by the relevant literature regarding possible complications with other procedures, this particular procedure is relative risk-free. In conjunction with the satisfying results regarding pain and paralysis removal, the extraordinarily low complication density of Nd-YAG PLDD culminates in the recommendation that the procedure should be applied to patients who are between unsuccessful conservative therapy and other operative methods.

HIV Lipodystrophy Case Definition using Artificial Neural Network Modelling

Objective

A case definition of HIV lipodystrophy has recently been developed from a combination of clinical, metabolic and imaging/body composition variables using logistic regression methods. We aimed to evaluate whether artificial neural networks could improve the diagnostic accuracy.

Methods

The database of the case-control Lipodystrophy Case Definition Study was split into 504 subjects (265 with and 239 without lipodystrophy) used for training and 284 independent subjects (152 with and 132 without lipodystrophy) used for validation. Back-propagation neural networks with one or two middle layers were trained and validated. Results were compared against logistic regression models using the same information.

Results

Neural networks using clinical variables only (41 items) achieved consistently superior performance than logistic regression in terms of specificity, overall accuracy and area under the ROC curve. Their average sensitivity and specificity were 72.4 and 71.2%, as compared with 73.0 and 62.9% for logistic regression, respectively (area under the ROC curve, 0.784 vs 0.748). The discriminating performance of the neural networks was largely unaffected when built excluding 13 parameters that patients may not have readily available. The average sensitivity and specificity of the neural networks remained the same when metabolic variables were also considered (total 60 items) without a clear advantage against logistic regression (overall accuracy 71.8%). The performance of networks considering also body composition variables was similar to that of logistic regression (overall accuracy 78.5% for both).

Conclusions

Neural networks may offer a means to improve the discriminating performance for HIV lipodystrophy, when only clinical data are available and a rapid approximate diagnostic decision is needed. In this context, information on metabolic parameters is apparently not helpful in improving the diagnosis of HIV lipodystrophy, unless imaging and body composition studies are also obtained.

A biophysical explanation for Nd:YAG percutaneous laser disc decompression success

OBJECTIVE

To use pre- and postoperative CT density measurements to demonstrate changes achieved by Nd:YAG laser (1,064 nm) in protruded or extruded discs.

BACKGROUND DATA

Nonendoscopic percutaneous laser disc decompression and nucleotomy (PLDN) with the Nd:YAG laser is an established minimal invasive treatment of discogenic pain syndromes in patients with bulging, protruded, or extruded intravertebral discs. Extremely high success rates involving improvement in the flow of cerebrospinal fluid in the dural sac and enhanced venous flow by MRI myelography are 80% lumbar, 86.5% cervical, and 98% thoracic spine. However, verification of reduced intradisc and intraspinal pressure by imaging procedures is difficult.

METHODS

Twenty-one patients, four women and 17 men, with an average age of 43.67 (range, 24-59) were selected. The patients showed lumbar radicular pain syndromes with monosegmental disc protrusion or extrusion, and monoradicular clinical symptoms. Measurements were performed preoperatively and on postoperative day 1.

RESULTS

The preoperative density measurements averaged 83.43, in agreement with the Houndsfield units (HU) described in the literature. Postoperatively, the reduction down to 66.33 HU had a statistical significance of p = 0.001 verified in the t test. Standardizing the measurements prior to laser irradiation to 100% produced an average 20% postoperative density reduction.

CONCLUSION

PLDN with the Nd:YAG laser (1,064 nm) markedly reduces the postoperative density in protrusion and extrusion of intravertebral discs. The excellent therapeutic results achieved with this method in discogenic pain syndromes can be verified by imaging procedures.

The role of human papillomavirus deoxyribonucleic acid assay and repeated cervical cytologic examination in the detection of cervical intraepithelial neoplasia among human immunodeficiency virus-infected women. Cervical Disease Study Group of the American Foundation for AIDS Research Community Based Clinical Trials Network

OBJECTIVES

We sought to measure the characteristics of a quantitative human papillomavirus deoxyribonucleic acid assay and repeated cervical cytologic examination in screening for cervical intraepithelial neoplasia among human immunodeficiency virus-infected women.

STUDY DESIGN

Human immunodeficiency virus-infected women with screening CD4+ lymphocyte counts of < or = 500 cells/mm3 (n = 103) were examined by quantitative human papillomavirus deoxyribonucleic acid assay and serial cervical cytologic examination and by colposcopy with biopsy and endocervical curettage during the course of 1 year.

RESULTS

Quantitative measures of total human papillomavirus deoxyribonucleic acid and high-risk human papillomavirus deoxyribonucleic acid were strongly associated with any cervical intraepithelial neoplasia (P = .005) and high-grade cervical intraepithelial neoplasia (P = .0006), but they improved the sensitivity and negative predictive value of baseline screening only slightly when combined with cervical cytologic examination. Incident cervical intraepithelial neoplasia occurred frequently (20%) during 1 year of follow-up and was more common among human papillomavirus-infected women. Repeated cytologic examination identified 60% of women with new cervical intraepithelial neoplasia.

CONCLUSION

Human immunodeficiency virus-infected women with at least mild immunosuppression have a high incidence of cervical intraepithelial neoplasia, which warrants close follow-up. Those with high baseline human papillomavirus deoxyribonucleic acid levels may be at the highest risk for incident cervical intraepithelial neoplasia.

Evaluation of simplified protease inhibitor dosing regimens for the treatment of HIV infection

Complicated dosing regimens can unfavorably affect patient adherence and drug efficacy. In an effort to increase adherence while maximizing the benefits of the protease inhibitor (PI) component of HAART, the efficacy and safety of less frequent PI dosing regimens have recently been under scrutiny. Limiting the number of drugs required in antiretroviral therapy regimens may also minimize toxicity and drug-drug interactions. This article reviews the current movement toward twice-daily regimens and examines the efficacy and safety data available on twice-daily dosing of amprenavir, indinavir, nelfinavir, saquinavir soft-gel capsules, and ritonavir. Future trends in dosing are also discussed.

Technical aspects of the percutaneous cervical and lumbar laser-disc-decompression and -nucleotomy

To achieve optimal results during percutaneous cervical and lumbar laser-disc-decompression, technical aspects have to be taken into consideration for this minimally invasive operation. The selection of the laser system is thus most significant. A Neodym-YAG-Laser is applied with a wavelength of 1064 nm which, compared to vaporization, has the prerequisites for shrinking from the experimental viewpoint. Selection of parameters for the application of energy depends on size and position of the cervical and lumbar discs. A needle with a mandrin having an outer cross section of up to 2 mm is used to puncture the disc. An ultrasharp needle tip is important. The approach depends on the section of the vertebral column involved. The insertion of the needle in the cervical discs is from the right side ventral and dorsolateral in thoracic and lumbar regions. In difficult cases of spondylophytes the insertion is helped by the so-called punctual laserosteotomy through the spondylophytes, which does not require any additional equipment at the operating table. The C-bow is sufficient for X-ray equipment and has to be adjusted according to the disc position. This minimal invasive procedure shows a technical failure rate of only 1.5/1000 in 2535 percutaneous laser disc decompressions and nucleotomies. There are two malfunctions of the laser machine and one of the X-ray technique. The PLDN using Nd-YAG 1064 nm is a technically perfect method with a very high standard of safety.

[Results of total endoprosthetic treatment of dysplasia coxarthrosis with additional autologous acetabuloplasty of the roof of the acetabulum]

With reference to the different operative treatments of dysplasia coxarthroses with a total hip endoprosthesis, 43 operations on the hip joint performed from 1975 to 1979 with a filling up to the acetabular roof defect with an autogenous bone graft had a clinical and roentgenological follow-up. The results were evaluated by means of a standardised procedure, and it was demonstrated with the help of clear successes that also anatomopathologically complicated cases can be provided with a suitable total endoprosthesis.

[Anchoring experiments on human cadaver vertebrae using various types of screws]

The firmness of the bone structure of vertebrae of human cadavers was investigated by turning screws of four different types into vertebrae T6 to L5 and subjecting them to axial tension up to the point of extraction. It was found that the cancellous bone screws (rather than the Zielke screw) had the best anchoring characteristics in bone tissue. The shearing fracture stress of the vertebral bone tissue was found to be approx. 1.80 N/mm2; the relation between the extraction forces and the individual vertebrae was also examined. In addition, the extraction forces were determined for screws inserted into vertebrae T6 to L4, as performed in Zielke's ventral spondylodesis procedure, as well as the lower tolerance limit for each vertebra in this segment of the vertebral column.

[Rate of maturation of osteons]

This paper examines the dynamics of Havers'ian remodelling and the concept of maturation rate of poly-chrome fluorescence-labeling osteons by means measurements of bone formation. It was used cortical bone of rabbit and merino sheep on various experimental conditions (Normal bone growth in the diaphysis of large bone and cortical bone of iliac crest, secondary fracture healing in tibia osteosyntheses with external fixation and oligotrophic pseudoarthrosis in rabbit. Gap healing of fractures in tibia osteosyntheses with external fixation and compression in the sheep). The diameters of labels were measured and the mathematical function of maturation rate of osteons was made out. The results were compared on the different experiment conditions. Statistical analyses have shown that the results of mathematical function and the values of their constants are not significantly different. These results seem to suggest that the rate of formation of the osteon is optimal on the various conditions and it is not use stimulating the osteoblastic activity with stimulation-therapy. The described model shows important informations of bone remodeling and adds new facts to the understanding of formal genesis of bone growth and fracture healing.

The pericapsular osteotomy of the os ilium in the treatment of flat acetabula

The operative correction of the pathological flat acetabulum in congenital dislocation of the hip, myelodysplasia and cerebral palsy can be performed with pelvic osteotomies and acetabuloplasties. In the light of our own experiences gained with different methods we prefer the pericapsular osteotomy of the ilium according to Pemberton since 1971. After the evaluation of the results the advantages of the method compared with other procedures are presented in the light of the improvements of correction and the rate of complication.

[Transoropharyngeal approach to C 1 and C 2]

In rare cases of diseases or traumatic lesions of C1 and C2 it is possible to prefer the short way with the transoropharyngeal approach. The operative procedure is described. Specialities are explained in three cases. A metallic osteosynthesis in case of odontoid fracture is seldom indicated.

[Feasibility and limitations of reconstructive interventions in rheumatoid arthritis and Bekhterew's disease]

Among the reconstructive interventions in rheumatoid arthritis preponderate the arthroplasties, among them again the resection arthroplasties in contrast to the alloarthroplasties. The resection arthroplasties are most frequently performed on the forefoot and on the hand joint and the cubital joint. The artificial joint substitute is possible nearly on every joint. As to the hip joint the problems are already satisfactorily solved, not yet, however, on the knee joint. In Bechterew's disease the indication to the alloarthroplasty is to be rendered depending less on pain than on function. In severe kyphoses the columnotomy is to be taken into consideration.

Electrical stimulation of the callus formation by means of bipolar rectangular pulse sequences

The clinical application of the electrical stimulation, lasting several weeks, for the callus formation is reported in 11 patients. Bipolar rectangular pulse sequences were used for the stimulation at a frequency of 1 Hz and a current intensity of +/-20mu amp. The electrical stimulation was successfully employed after distraction osteotomies with a KDA-apparatus in shortening of the leg provoked by different causes or in the treatment of pseudarthroses. The realignment of the newly formed callus and the osseous consolidation are stimulated and speeded up by the bipolar rectangular pulse sequences as it is also shown in the light of the roentgenograms of a case.