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Classification systems for groin hernias.

All groin hernia classifications are somewhat arbitrary and artificial. Currently, there is no consensus among either general surgeons or hernia specialists as to a preferred system. A survey by Zollinger in 1998 of hernia specialists in North American and Europe showed, that although the Nyhus, Gilbert, and Schumpelick-Arit systems were commonly used, the majority of these specialists still used the traditional classification for groin hernias. It is apparent that only the traditional classification of groin hernias has stood the test of time. As stated by Fitzgibbons, "the primary purpose of a classification system for any disease is to stratify for severity so that reasonable comparisons can be made between various treatment strategies." Given the multiplicity of operative techniques and approaches for the repair of groin hernias, it appears that no one classification system can satisfy all. With time, it is likely that we surgeons will settle upon a given operation for a specific type of inguinal hernia. For that given operation to be accepted as proven best, however, it is essential the competing operations be applied to simliar (classified) groups of groin hernia patients.

Hernia, Femoral↗

Inpatient disposition classification for the creation of hospital surge capacity: a multiphase study.

BACKGROUND: The ability to provide medical care during sudden increases in patient volume during a disaster or other high-consequence event is a serious concern for health-care systems. Identification of inpatients for safe early discharge (ie, reverse triage) could create additional hospital surge capacity. We sought to develop a disposition classification system that categorises inpatients according to suitability for immediate discharge on the basis of risk tolerance for a subsequent consequential medical event. METHODS: We did a warfare analysis laboratory exercise using evidence-based techniques, combined with a consensus process of 39 expert panellists. These panellists were asked to define the categories of a disposition classification system, assign risk tolerance of a consequential medical event to each category, identify critical interventions, and rank each (using a scale of 1-10) according to the likelihood of a resultant consequential medical event if a critical intervention is withdrawn or withheld because of discharge. FINDINGS: The panellists unanimously agreed on a five-category disposition classification system. The upper limit of risk tolerance for a consequential medical event in the lowest risk group if discharged early was less than 4%. The next categories had upper limits of risk tolerance of about 12% (IQR 8-15%), 33% (25-50%), 60% (45-80%) and 100% (95-100%), respectively. The expert panellists identified 28 critical interventions with a likelihood of association with a consequential medical event if withdrawn, ranging from 3 to 10 on the 10-point scale. INTERPRETATION: The disposition classification system allows conceptual classification of patients for suitable disposition, including those deemed safe for early discharge home during surges in demand. Clinical criteria allowing real-time categorisation of patients are awaited.

Bed Occupancy↗

Classification of urinary stones by cluster analysis of ionic composition data.

The cluster analysis technique is considered for classifying kidney stones based on data for nine chemical analysis parameters. A set of 214 stones is used, which has been previously classified using empirical classification rules into three stone types using the percentage concentrations of the urate, oxalate, and phosphate radicals. We investigate whether cluster analysis utilising data on all parameters leads to different classifications and explore the possibility of other effective classifiers. We also compare the performance of various clustering techniques, distance and similarity measures and data standardisation methods. Results indicate that inclusion of the additional six parameters does not improve the classification accuracy. Best matching with the empirical classification (6% error) is achieved using the average linkage (between groups) clustering method and the squared Eculidean distance measure without data standardisation. Excluding these three main radicals causes a 63% matching error. Cluster analysis results suggest that carbon ions alone provide a single classifier for the three stone types, giving a matching error of approximately 10% with the empirical classification.

Cluster Analysis↗

From diversity to unity. The classification of mental disorders in 21st-century China.

Psychiatric disease constructs represent social constructs and genuine states of distress that have biopsychosocial sources. As such, they have social uses peculiar to the social groups in which they are created and legitimized. This is as true in the United States as in the rest of the world. The DSM schema, for instance, is so organized that every possible mental condition is listed as a disease to legitimate remuneration to practitioners from private medical insurance and government programs. This particular social use may be irrelevant to other societies where health care is financed differently. The CCMD-3 system represents an attempt at global unification and preservation of features that are salient for local application. Compared with its previous editions, noticeable changes have been made to render it in tune with international usage. This remarkable speed of adaptation speaks to the global flows of information technology and China's openness under rapid economic reform. It also demonstrates that the middle-aged cohort of more pragmatic Chinese psychiatric leaders who headed the CCMD-3 task force are now less vulnerable to the domination of the most senior generation of Chinese psychiatrists. Having been trained in the Russian system of psychiatry and gone through the various periods of national shame that traumatized China, they used to be very cautious about adopting foreign technology in general. This is why much less harmonization with the ICD-10 occurred with the CCMD-2-R, when the responsible task force was, for better or worse, dominated by these senior psychiatrists. Nonetheless, as Stengel and Sartorius remarked, an international classification must not aim to oust or replace regional classifications that serve valuable functions in the local contexts. No single classificatory system, Kirmayer submits, will suffice for all purposes--the correct diagnostic scheme is the one that accomplishes its explicit pragmatic aim by addressing the relevant level of description. The particular additions (e.g., travelling psychosis, culture-related mental disorders), deletions (e.g., depressive neurosis, pathologic gambling, avoidant and borderline personality disorders), retentions (e.g., unipolar mania, neurosis, hysteria, homosexuality), and epistemologic variations (e.g., somatoform disorder, neurasthenia) of diagnostic categories reflect exactly this simultaneous need to globalize and to take account of the changing reality of illness in contemporary China. Stengel advised that "no psychiatric classification can help being partly etiological and partly symptomatological, because these are the criteria by which psychiatrists distinguish mental disorders from each other." To an extent, the CCMD-3 is a critique of certain nosologic assumptions of Western psychiatry, such as the feasibility of a neo-Kraepelinian taxonomy grounded exclusively in symptomatology across all diagnostic categories, and the validity of syndromic architectures based on a firm adherence to the mind-body dichotomy. From this angle of vision, local systems of classification such as the CCMD-3 may offer an opportunity for needed reflections by North American psychiatrists who have simply taken the DSM-IV schema for granted. Sartorius reckoned that a classification is a way of seeing the world at a point in time. A deep study of the CCMD-3 is thus an avenue for achieving an understanding of the contemporary Chinese mind and the social realities in China. The remarkable diversity of China at present, namely, a Communist Party dominated state socialist political structure but the most rapidly growing capitalist economy in the world, guarantees that Chinese people's social and moral experience of illness will continue to change. The study of such culture-specific categories as travelling psychosis, neurasthenia, qigong-induced mental disorder, and dysfunctional homosexuality sheds light on the larger sociomoral processes and destabilizing changes in subjectivity that are occurring in this most populous country in the world.

China↗

The myelodysplastic syndromes: towards a functional classification.

The French-American-British classification of myelodysplastic syndromes (MDS) has contributed greatly to better communication and conduct of clinical trials. However, the advent of novel cytogenetic, immunological and molecular techniques in recent years warrant some alterations to this purely morphological classification. This review aims at highlighting the advances which reflect more closely the unique biological and clinical features of various subtypes of MDS. We propose a comprehensive classification of MDS, to include the newly defined categories, as well as those not included in previous classifications, such as the therapy-induced and hereditary MDS. We hope that this classification will help in focusing attention on the biological features of MDS, the understanding of which will be crucial to combat this disease.

Adult↗

Evaluation of 239 cases of perinatal death using a fundamental classification system.

OBJECTIVE: To classify 239 cases of perinatal death in a newly introduced classification system for underlying causes of perinatal death. DESIGN: Prospective, descriptive. SETTING: Dutch healthcare region Delft-Westland-Oostland (DWO). MATERIALS AND METHODS: In 10 years (1983-1992), all cases of perinatal death with a birthweight above 500 g (n=239) were included into the study. We used a classification model based upon the underlying cause of death using simple principles of obstetrical and neonatal pathology. A team consisting of a gynaecologist, neonatologist and pathologist classified all cases of perinatal death into seven groups to determine the "most-probable" cause of death. RESULTS: Birth trauma was seen in two cases (0.8%). Infections were seen in 16 cases (6.8%). Acute/subacute placental pathology in 77 cases (32.2%) and chronic placental pathology in 50 cases (21%). Bloodtype antagonism was seen in two cases (0.8%). Lethal congenital malformations in 55 cases (23%). Complications of pre-viable delivery in 20 cases (8.4%). Unclassifiable were 17 cases (7%): two cases could not be classified despite thorough investigation (1%) and 15 cases were lost for follow-up (6%). CONCLUSIONS: Classification of perinatal death causes by using our fundamental classification system gives insight in the possible underlying causes of death. The results of such a classification can be used as guidelines for preventive measures in the future.

Bacterial Infections↗

Histological classification of gastric cancer from initial to advanced stages.

An ideal classification of malignant tumors should imply not only the histogenesis of the tumor and adequate reproducibility of its specific characteristics by other investigators, but also an exact definition of the stages of tumor development to facilitate prognostic prediction. The present paper proposes a classification of gastric carcinoma with emphasis on the initial stages of malignant transformation. The classification is based on the analysis of early invasive gastric cancer observed in biopsy material from the Institute of Pathology of Münster University. Since 1974, all cases of severe dysplasia or early gastric cancer were selected from a total of 200,000 gastric biopsies and more than 1500 gastric resections, and subjected to special work-up. In analogy to Clark's classification of malignant melanoma (Clark et al., 1969) the proposed classification defines consecutive stages of development in gastric carcinoma with special regard on the maximum depth of invasion and vertical thickness of the tumor, together with its histologic type and the predominant direction of tumor spread.

Adenocarcinoma↗

Linell classification of breast cancer morphology compared to histologic grading, S-phase fraction and DNA-ploidy.

One hundred and fifty-eight histologically verified mammary carcinomas with known mammographic doubling time (DT) were studied with special emphasis on a morphologic classification proposed by Linell et al. [8, 12, 14, 15]. The hypothesis that Linell classification of ductal carcinomas into comedo, tubuloductal and tubular carcinomas is easy to perform with small inter-observer variations, was not fully confirmed. The Linell classification was found to correlate well with conventional WHO malignancy grading, S-phase fraction and DNA-ploidy. The Linell classification also correlated to surgical stage, lymph node status and DT, but not at all to tumour size. Using distant disease-free survival as an endpoint, the Linell classification gave prognostic information comparable to conventional histologic grading, seeming to be a simple, cheap and reliable method well worth trying on a larger scale.

Adenocarcinoma↗

Head-and-neck stages I and II extranodal non-Hodgkin's lymphomas: real classification and selection for treatment modality.

PURPOSE: We re-evaluated histopathological specimens of head and neck early-stage extranodal non-Hodgkin's lymphoma (NHL) using the revised European and American lymphoma (REAL) classification, and also investigated the relationship between the clinical characteristics and histopathological classification in an attempt to evaluate the usefulness of this new classification system in selecting treatment modalities. MATERIALS AND METHODS: Between 1979 and 1995, 117 patients with histologically confirmed stages I and II NHL of head-and-neck extranodal regions were treated. Of these patients, 110 specimens were available for re-evaluation. Sixty-four patients had Stage I, and 46 had Stage II diseases. All but 3 had received radiation therapy, and 59 patients were also treated with intensive combination chemotherapy. RESULTS: There were 32 extranodal marginal-zone B-cell lymphomas, 57 diffuse large B-cell lymphomas, 11 peripheral T/NK-cell lymphomas, and 10 others. The 5- and 10-year cause-specific survival rates for all patients were 72% and 62%, respectively. Patients with extranodal marginal-zone B-cell lymphoma or other low-grade B-cell lymphomas demonstrated higher survival rates than patients with other lymphomas. Patients with peripheral T/NK lymphomas showed the lowest survival rate. CONCLUSION: The REAL classification accurately indicated the prognosis of patients with NHL. These results suggest that appropriate treatment modalities can be selected using this classification.

Adolescent↗

Treatment results of radiotherapy for malignant lymphoma of the orbit and histopathologic review according to the WHO classification.

PURPOSE: To analyze the results of radiotherapy (RT) for malignant lymphoma of the orbit and to evaluate them compared with the World Health Organization (WHO) classification published in 2001. METHODS AND MATERIALS: The data from 29 patients with malignant lymphoma of the orbit treated with RT at Gunma University Hospital between 1978 and 2001 were retrospectively analyzed. Pathologic slides from 23 cases were available and were reviewed by a hematopathologist according to the WHO classification. The original and reviewed diagnoses, patient characteristics, treatment results, and complications were analyzed. In principle, patients with low-grade or indolent lymphoma were treated with RT alone, using 30 Gy as the tumor dose. Survival data were calculated using the Kaplan-Meier method. RESULTS: One case that proved to be a pseudotumor was excluded from evaluation. Of the 28 cases, 25 were Stage IAE, 1 was Stage IIAE, and 2 were Stage IVAE. The median follow-up was 71 months. According to the original classification and the Working Formulation, the 5- and 10-year overall survival rate of patients with low-grade lymphoma was 94% and 73%, respectively. The corresponding rates for those with intermediate-grade lymphoma were 67% and 67% (p = 0.15). In contrast, the WHO classification showed a significant difference in the survival curves. The 5- and 10-year overall survival rate of patients with mucosa-associated lymphoid tissue (MALT) lymphoma was 100% and 88%, respectively; for diffuse large B-cell patients, the rates were both 0% (p < 0.001). In patients with MALT lymphoma, one local and four distant relapses developed; two of them >10 years after initial treatment. All of the relapsed MALT lymphomas were controlled by salvage therapy. CONCLUSION: Excellent local control and survival can be achieved for patients with orbital MALT lymphoma using RT alone. A precise histopathologic diagnosis using the WHO classification and long-term follow-up for >10 years is recommended.

Adult↗

How accurate are the European Union's classifications of chemical substances.

The European Commission has decided on harmonized classifications for a large number of individual chemicals according to its own directive for classification and labeling of dangerous substances. We have compared the harmonized classifications for acute oral toxicity to the acute oral toxicity data available in the RTECS database. Of the 992 substances eligible for this comparison, 15% were assigned a too low danger class and 8% a too high danger class according to the RTECS data. Due to insufficient transparency-scientific documentations of the classification decisions are not available-the causes of this discrepancy can only be hypothesized. We propose that the scientific motivations of future classifications be published and that the apparent over- and underclassifications in the present system be either explained or rectified, according to what are the facts in the matter.

Animals↗

Evaluation of breast microcalcifications according to Breast Imaging Reporting and Data System criteria and Le Gal's classification.

INTRODUCTION/OBJECTIVE: Our aim was to evaluate the positive predictive value (PPV) of the analysis of breast microcalcifications according to Breast Imaging Reporting and Data System (BI-RADS) and Le Gal's classification in identification of malignancy, and to assess the interobserver agreement using these criteria. METHODS AND MATERIAL: Eighty-two patients with breast microcalcifications on their screening mammograms underwent surgical excision after a needle localization at our institution between July 1993 and June 2000. The mammograms were examined by two experienced mammographers retrospectively and independently. Each observer noted the morphology, distribution, associated findings, final assessment categories of microcalcifications according to BI-RADS criteria and the morphologic type of microcalcifications according to Le Gal's classification. The PPVs for each radiologist and the interobserver agreement were determined by using these data and histologic findings. RESULTS: Histopathologic results yielded malignancy in 25 (30%) cases. The evaluation of microcalcifications according to BI-RADS criteria revealed PPVs of 17% and 25% for category 4 lesions, and 68% and 44% for category 5 lesions. In the assessment of microcalcifications according to Le Gal's classification, the PPV of type 4 lesions was 45% (for both observers), whereas the PPVs of type 5 lesions were 70% and 50%. The interobserver agreement was fair in evaluation of morphology of microcalcifications (kappa:0.31), distribution of microcalcifications (kappa:0.29), final assessment categories (kappa:0.27), and moderate in evaluation of associated findings (kappa:0.48) by using BI-RADS lexicon. It was higher for the assessment of milk of calcium and round microcalcifications than other typically benign microcalcifications, and for fine linear or fine linear branching microcalifications than other probably malignant calcifications. There was a fair interobserver agreement (kappa:0.30) in the description of the morphologic type of microcalcifications according to Le Gal's classification. DISCUSSIONS AND CONCLUSION: In our study, both BI-RADS lexicon and Le Gal's classification did not succeed expectedly in reducing the ambiguity in assessment of breast microcalcifications. Further studies and perhaps development of new methods are required to improve accuracy and standardization in mammographic interpretation.

Breast Neoplasms↗

Development, test reliability and validation of a classification for revision hip arthroplasty.

The objective of the study was to develop a valid and reliable classification system for failed hip arthroplasties. The study uses research principals derived from multi-attribute utility theory and consensus group techniques. The development of the severity measure was done in two phases. Phase I of the study included: (a) questionnaire development, (b) submission of the questionnaire to the respondents, (c) data synthesis of the responses and item reduction, and (d) classification development and inter-observer reliability testing. Phase II included: (a) resubmission of the instrument to the respondents for suggestions/feedback, (b) instrument revision by the co-investigators based on the respondents' second feedback, and (c) inter-observer reliability testing and intraoperative validity testing of the instrument. The questionnaires sought to capture expert opinion as to what clinical determinants obtained preoperatively (during patient interview, physical exam and review of plain radiographs - AP pelvis and hip lateral) that would in their clinical experience reveal intraoperative severity. There was an 80% (16/20) response rate from the outside experts invited to participate in the study. Based on item reduction and test retest analysis, a five-grade radiographic classification for the acetabulum as well as the femur was developed. This system was then reviewed by 13 of the initial outside experts (16, 80%) who participated in the first round. Inter-rater reliability testing of the final format of the classification revealed a weighted kappa statistic value of 0.88 between the two-blinded raters (inter-rater reliability) and 0.87 between the blinded raters and the reference standard (intraoperative validity). We conclude that the study developed a reliable and valid radiographic classification system for failed hip arthroplasty.

Arthroplasty, Replacement, Hip↗

A comparison of the reliability and validity of bone stock loss classification systems used for revision hip surgery.

Three femoral (Paprosky, American Academy of Orthopaedic Surgeons [AAOS], and Endo-Klinik) and 2 acetabular (Paprosky, AAOS) bone stock loss classification systems were evaluated for reliability. Four observers (2 consultants, 2 registrars) graded the bone loss in 25 patients using preoperative radiographs. Grading was repeated after a minimum of 2 weeks. Interobserver and intraobserver reliability was investigated. The kappa statistic was used to assess levels of agreement. Intraobserver agreement ranged from poor to good. Interobserver agreement ranged from fair to moderate. The validity of the Paprosky classification system was evaluated, comparing preoperative bone stock loss assessment with intraoperative findings. Agreement levels of moderate (femoral classification system) to good (acetabular classification system) were achieved. Bone stock loss classification systems are shown to be inconsistent and unreliable.

Arthroplasty, Replacement, Hip↗

Improved learning algorithms for mixture of experts in multiclass classification.

Mixture of experts (ME) is a modular neural network architecture for supervised learning. A double-loop Expectation-Maximization (EM) algorithm has been introduced to the ME architecture for adjusting the parameters and the iteratively reweighted least squares (IRLS) algorithm is used to perform maximization in the inner loop [Jordan, M.I., Jacobs, R.A. (1994). Hierarchical mixture of experts and the EM algorithm, Neural Computation, 6(2), 181-214]. However, it is reported in literature that the IRLS algorithm is of instability and the ME architecture trained by the EM algorithm, where IRLS algorithm is used in the inner loop, often produces the poor performance in multiclass classification. In this paper, the reason of this instability is explored. We find out that due to an implicitly imposed incorrect assumption on parameter independence in multiclass classification, an incomplete Hessian matrix is used in that IRLS algorithm. Based on this finding, we apply the Newton-Raphson method to the inner loop of the EM algorithm in the case of multiclass classification, where the exact Hessian matrix is adopted. To tackle the expensive computation of the Hessian matrix and its inverse, we propose an approximation to the Newton-Raphson algorithm based on a so-called generalized Bernoulli density. The Newton-Raphson algorithm and its approximation have been applied to synthetic data, benchmark, and real-world multiclass classification tasks. For comparison, the IRLS algorithm and a quasi-Newton algorithm called BFGS have also been applied to the same tasks. Simulation results have shown that the use of the proposed learning algorithms avoids the instability problem and makes the ME architecture produce good performance in multiclass classification. In particular, our approximation algorithm leads to fast learning. In addition, the limitation of our approximation algorithm is also empirically investigated in this paper.

Journal Article↗

Classification systems for upper-limb musculoskeletal disorders in workers: a review of the literature.

OBJECTIVE: The purpose of this study was to provide a review of the available classification systems and to describe the similarities and differences in the structure of these systems. METHODS: Classification systems of upper limb musculoskeletal disorders (MSDs) were located via electronic database searches and researchers' files. The classification systems were compared on the disorders they described and on the criteria presented for each disorder. RESULTS: Twenty-seven classification systems were found after title, abstract, or full article review of 1671 articles. The systems differed in the disorders they included, the labels used to identify the disorders, and the criteria used to describe the disorders. CONCLUSION: Twenty-seven classification systems were found that described disorders of the muscle, tendon, or nerve that may be caused or aggravated by work. No two systems were the same.

Humans↗

Revision of the International Classification of Impairments, Disabilities, and Handicaps: developmental issues.

Variability in approaches to define and classify disability has constituted persistent problems in documenting the epidemiology of disability and providing appropriate services. The major institutions of health care, mental health, and welfare often have separate systems of classification and terminology related to defining eligibility for programs and funding for services. In 1980, the International Classification of Impairments, Disabilities and Handicaps-ICIDH was published by the World Health Organization as a companion document of the International Classification of Disease to document the consequences of illness or injury. Current problems concerning the classification of childhood disability in health, education, and related services have resulted in growing interest in the revision of the ICIDH as a classification tool. The strengths and limitations of the ICIDH are examined in general, as well as with specific reference to its ability to document the nature and epidemiology of childhood disability. This paper (1) describes the ICIDH taxonomy and representative contributions; (2) reviews issues and concerns contributing to its revision; (3) summarizes changes in the revised ICIDH2 draft document, and (4) identifies issues of particular relevance to children and public health applications.

Activities of Daily Living↗

The international classification of the epilepsies and epileptic syndromes. An algorithm for its use in clinical practice.

An algorithm has been structured as a guided reading of the international league against epilepsy (ILAE) syndromic classification to be used in clinical practice by less experienced physicians in newly diagnosed patients. The algorithm followed the original structure of the classification, which identifies major syndromic groups, subgroups, and specific syndromes. Validation required two raters, a resident and a board-certified neurologist, to apply the algorithm with different techniques (direct or recorded interview, medical record consultation) to 19 children and 18 adults with epilepsy with information available at the time of diagnosis. The two raters' diagnoses were compared with those of the caring physicians, and cases where disagreement arose were discussed in conference to achieve consensus. The kappa statistic was used as a measure of inter-rater agreement. Caring physicians and both raters agreed in 51% of cases. Substantial agreement (kappa = 0.75) was obtained between the resident and the neurologist on major diagnostic groups and subgroups, mostly in adults. Agreement with the caring physician was slightly more satisfactory for the resident (kappa=0.67) than for the neurologist (kappa = 0.60). Agreement was better with direct or indirect interview than with record consultation, and improved further after discussion. Agreement was obtained after discussion in 32% of cases, in some of which the caring physician agreed on the resident's diagnosis. Agreement was less satisfactory for specific syndromes. On this basis, an algorithm of the ILAE classification is a fairly reliable instrument only for making a broad syndromic classification of epilepsy at the time of diagnosis. The limits of the algorithm tend mostly to reflect the intrinsic limitations of the classification itself.

Adolescent↗