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PubMed1993

Comparison of survival curves of gastric cancer patients after surgery according to the UICC stage classification and the General Rules for Gastric Cancer Study by the Japanese Research Society for gastric cancer.

OBJECTIVE: This study compared the UICC classification with the General Rules for Gastric Cancer Study (GRGCS) of the Japanese Research Society by analyzing recent results of gastric cancer surgery in Japan. SUMMARY BACKGROUND DATA: The present UICC stage classification for gastric cancer was published in 1987 and the Japanese GRGCS were published in 1985. Both are based on the results of surveys conducted in the early 1970s. METHODS: The survival curves of 926 patients, who underwent gastric cancer surgery between 1982 and 1985 at Kyoto University Hospital and its 31 associated hospitals, were analyzed according to the UICC classification and the GRGCS using SAS computer software. RESULTS: There was no difference in survival rate between UICC stages IA and IB. GRGCS stage III was found to include UICC stages II, IIIA, and IIIB, and GRGCS stage IV included UICC stages IIIA, IIIB, and IV, with significantly different survival rates. In contrast, each UICC stage included different GRGCS stages with no significant differences in survival rates. The survival rate of stage IV patients of both classifications who underwent gastrectomy was significantly higher than that of stage IV patients receiving bypass or exploratory surgeries. CONCLUSIONS: The UICC classification is better than the GRGCS for classifying gastric cancer in Japan. However, UICC stage I does not need to be subdivided into stages IA and IB, and stage IV should be further subdivided into stages IVA and IVB according to the surgery performed: IVA, gastrectomy, and IVB, bypass or exploratory surgery.

Humans↗
PubMed1996

Further considerations on the Revised European-American Lymphoma classification.

The proposal from the International Lymphoma Study Group (ILSG) of a new classification for lymphoid neoplasm, known as the Revised European-American Lymphoma (REAL) classification, has been received by clinicians and pathologists with mixed reactions. Numerous letters, editorials, and abstracts have been published in the past year praising and criticizing this proposal. The feasibility as well as the clinical validity of the ILSG proposal has been tested in retrospective studies based on large multicenter trials, and a large multi-institutional effort to prove or disprove the validity of the REAL classification was undertaken by the International Non Hodgkin's Lymphoma Classification Project. All these studies seems to confirm the usefulness of the REAL classification. Besides the overall evaluation of the ILSG proposal, the clinical validity of the newly defined entities (eg, mantle cell lymphoma, marginal zone cell lymphoma) has been shown by these and other retrospective studies. However, the main objection of clinicians remains the lack of grouping of lymphoma entities according to their clinical behavior, which we as pathologists believe to be the clinician's task.

Humans↗
PubMed2001

Classification of osteonecrosis of the femoral head. Reliability, reproducibility, and prognostic value.

The purpose of the current investigation was to determine interobserver and intraobserver reliability of the classification system of Steinberg et al for osteonecrosis of the femoral head. Sixty-five anteroposterior and lateral radiographs of hips were selected randomly from a pool of patients with confirmed osteonecrosis of the femoral head. Six fellowship-trained observers viewed the radiographs (Reading 1). The observers used six main stages of the classification excluding A, B, and C subgroups. The same observers viewed the radiographs 4 months later in reverse order (Reading 2). Reading 1 was used to calculate interobserver kappa values. Reading 2 was used to calculate intraobserver kappa values. Stage-specific kappa values for interobserver variation between all viewers were as follows: Stage I, k = 0.64; Stage II, k = 0.51; Stage III, k = 0.21; Stage IV, k = 0.49; Stage V, k = 0.36; and Stage VI, k = 0.80. Stage-specific kappa values for intraobserver variation between all viewers were as follows: Stage I, k = 0.74; Stage II, k = 0.60; Stage III, k = 0.46; Stage IV, k = 0.59; Stage V, k = 0.27; and Stage VI, k = 0.78. An average of 10 of 21 (48%) of these errors involved Stage III. An average of 6.3 of 21 (30%) intraobserver errors involved Stage V. The presence of the crescent sign in Stage III and joint space narrowing in Stage V markedly diminished the overall reliability of any four- to six-stage classification system. Based on the authors' experience and analysis of the current classifications of osteonecrosis of the femoral head, an easy and reproducible Pittsburgh classification system is proposed.

Female↗
PubMed1993

Histopathologic classification of cervical carcinomas and recognition of mucin-secreting squamous carcinomas.

Recently, cervical mucin-secreting squamous carcinomas have been reported to be more common in younger women than in older women, leading some to conclude that any histologic classification of cervical carcinoma should include a specific category of this tumor type. One hundred and ninety-six invasive cervical carcinomas were classified using two histologic classification systems--the World Health Organization (WHO) and a system that recognized mucin-secreting squamous carcinomas (Fox). Analyses were performed to determine whether there was an association between age and glandular tumor types in either system. In the WHO System, 72% were classified as squamous carcinoma, 22% adenocarcinoma, and 6% adenosquamous. In the Fox System, 54% were squamous carcinoma, 22% adenocarcinoma, 4% adenosquamous, and 20% squamous carcinoma with mucin secretion. Specimen type did not significantly affect the classification of a carcinoma. No association was established between age and a diagnosis of adeno- and adenosquamous carcinomas in the WHO System, or age and adeno-, adenosquamous, and mucin-secreting squamous carcinomas in the Fox System. We conclude that use of the WHO Classification System does not obscure significant epidemiologic trends that are evident in a classification system that identifies mucin-secreting squamous carcinomas.

Adenocarcinoma↗
PubMedDate not supplied

Olecranon fractures in children: Part 1: a clinical review; Part 2: a new classification and management algorithm.

Part 1: A Clinical Review: Fractures of the olecranon in children are uncommon, and the outcome has historically been reported as good. Management varies from simple immobilization to include various methods of internal fixation. Recently a new technique of fracture fixation has been used in an attempt to improve the management of this fracture. This article reviews olecranon fractures seen at two children's hospitals over a 10-year period. The purpose of the study was to review and classify various fracture patterns, different fixation techniques, and to assess medium-term outcomes after this uncommon injury. Part 2: A New Classification and Management Algorithm: A new classification system and management algorithm for fractures of the olecranon in children is presented. This was developed after a 10-year review of olecranon fractures and their management at two children's hospitals (Part 1). Minimally displaced or undisplaced fractures account for 80% of all olecranon fractures, and these are managed with immobilization, rarely requiring hospital admission. Of those fractures admitted to hospital, oblique metaphyseal fractures are most commonly seen and are satisfactorily treated with tension-band techniques, but a wide variety of fracture patterns are less common and may require different management. Previous classifications of this uncommon fracture have not addressed all of the significant features to categorize the fracture accurately or to imply a management pathway. This new anatomically based classification system facilitates accurate classification for research purposes, and its principles are applied in the clinical-management algorithm presented here.

Adolescent↗
PubMedDate not supplied

The effect of pediatric orthopaedic experience on interobserver and intraobserver reliability of the herring lateral pillar classification of Perthes disease.

An analysis was done of the effect of surgeons' pediatric orthopaedic experience on the classification of Perthes disease according to the lateral pillar classification described by Herring. Five observers with varied pediatric orthopaedic experience reviewed anteroposterior (AP) pelvis radiographs of 33 patients in the fragmentation phase of Perthes disease and classified each case on three separate occasions at least 24 hours apart. Frog-leg lateral-view radiographs taken at the same time were also classified using the same criteria based on the femoral head anterior column. Kappa statistics showed good agreement for intra- and interobserver reliability of classification for both AP and frog lateral radiographs. There were no statistically significant variations among the reviewers. Twenty-four percent of the cases had a classification one grade worse on the lateral radiograph compared to the AP view. The lateral pillar classification provides a reproducible radiographic technique for Perthes disease characterization independent of pediatric orthopaedic experience.

Adolescent↗
PubMed1993

Comparison of classification of the severity of hypertension by blood pressure level and by World Health Organization criteria in the prediction of concurrent cardiac abnormalities and subsequent complications in essential hypertension.

OBJECTIVE: To determine whether classification of the severity of hypertension according to the World Health Organization (WHO) system, which utilizes additional clinical and laboratory findings, is superior to classification by blood pressure level alone in predicting prognostically important cardiac structural abnormalities and the risk of subsequent complications in asymptomatic subjects. DESIGN: Two-hundred and twenty adults with uncomplicated essential hypertension underwent baseline clinical evaluation and echocardiography; 88% were subsequently followed for a mean of 11.6 years. SETTING: University hospital. RESULTS: Left ventricular mass index and relative wall thickness were slightly greater in patients in the highest diastolic or systolic blood pressure stratum than in WHO stage II hypertensives, but these results were statistically non-significant. High peripheral resistance index was best identified by diastolic blood pressure level. Receiver operating characteristic curve analysis showed that all three methods had similar test performance in predicting abnormal left ventricular mass index, left ventricular geometry, relative wall thickness and peripheral resistance. During follow-up the proportion of patients who had a clinical event or died increased with increasing severity stratum in all three clinical classification systems, but the trends were statistically non-significant. Risk stratification by echocardiographic left ventricular mass index was most successful in identifying patients at very high and very low risk of subsequent morbid events and all-cause mortality. CONCLUSION: Classification of hypertension severity by blood pressure level has similar, although limited, effectiveness at a lower cost than the WHO criteria in identifying patients with adverse cardiac changes and an impaired long-term prognosis. Echocardiographic measurement of left ventricular mass index was more successful than other classifications in predicting subsequent morbid events.

Adult↗
PubMed1997

Interobserver variation in the AO/OTA fracture classification system for pilon fractures: is there a problem?

OBJECTIVES: To evaluate the interobserver variation for the AO/OTA fracture classification system: region forty-three-pilon fractures. METHODS: One senior attending, two fellows (one trauma, one foot and ankle), one junior orthopaedic resident, and one experienced research coordinator independently classified eighty-four sets of radiographs. The evaluator was blinded as to treatment and functional outcome. The radiographs initially used to manage the patients were evaluated; no special radiographs or standardized radiographic techniques were used. The kappa statistic, Williams index, and SAV statistic were calculated. RESULTS: Using the SAV statistic to quantify rater agreement beyond that expected by chance alone, the average chance-adjusted agreement among the raters was 0.57 for fracture type, 0.43 for group, and 0.41 for subgroup. This is equivalent to moderate agreement (0.41 to 0.60). The kappa statistic was used to determine whether there was difficulty with any specific category of the AO type classification among raters for selecting fracture type (A, B, C). Kappa values were 0.49 for type A, 0.58 for type B, 0.57 for type C, all of which were considered adequate. CONCLUSION: These data are similar to others reported for interobserver agreement with the AO/OTA fracture classification and other classification systems. The issue of individual judgement in taking a continuous variable (fracture pattern) and compartmentalizing it into a dichotomous variable (fracture classification system) is highlighted by these data. Determination of fracture types alone (type A, B, or C) would seem to be sufficient for clinical research where fracture severity should be reported as a variable.

Ankle Injuries↗
PubMed1995

Afghan war wounded: application of the Red Cross wound classification.

OBJECTIVE: This study was designed to illustrate the application of the Red Cross classification system as a guide to treatment and to demonstrate its ease of use, especially in situations where the treating surgeons may have little experience with or knowledge of ballistic details. DESIGN: The wounds of 123 victims of fighting in Afghanistan are described and categorized according to the Red Cross classification system. MATERIALS AND METHODS: Recent factional fighting in Afghanistan resulted in 123 casualties being admitted to an International Committee of the Red Cross (ICRC) hospital in Quetta, Pakistan, close to the Afghan border. These casualties suffered more than 1300 wounds in total; the two most severe wounds in each casualty were categorized according to the Red Cross classification, described here. This wound classification is quick and easy to apply; it focuses the surgeon's attention on the wound, without requiring any familiarity with terminal ballistics. MEASUREMENTS AND MAIN RESULTS: The majority of wounds, caused by antipersonnel fragments (68.3% of casualties), affected only the soft tissues. Bullet wounds were fewer (22.8% of casualties), but tended to be more severe, often involving a fracture, vascular damage, or injury to a vital structure. CONCLUSIONS: The Red Cross classification permits identification of wound patterns and provides a data base for review of clinical practice and outcome. It is hoped that further data gathered in this manner from ICRC hospitals and others receiving war wounded will add to the understanding of the clinical practice and problems in war surgery.

Adolescent↗
PubMed2004

A new classification system for congenital laryngeal cysts.

OBJECTIVES: A new classification system for congenital laryngeal cysts based on the extent of the cyst and on the embryologic tissue of origin is proposed. STUDY DESIGN: Retrospective chart review. METHODS: The charts of 20 patients with either congenital or acquired laryngeal cysts that were treated surgically between 1987 and 2002 at the Hospital for Sick Children, Toronto were retrospectively reviewed. Clinical presentation, radiologic findings, surgical management, histopathology, and outcome were recorded. A new classification system is proposed to better appreciate the origin of these cysts and to guide in their successful surgical management. RESULTS: Fourteen of the supraglottic and subglottic simple mucous retention cysts posed no diagnostic or therapeutic challenge and were treated successfully by a single endoscopic excision or marsupialization. The remaining six patients with congenital cysts in the study were deemed more complex, and all required open surgical procedures for cure. On the basis of the analysis of the data of these patients, a new classification of congenital laryngeal cysts is proposed. Type I cysts are confined to the larynx, the cyst wall composed of endodermal elements only, and can be managed endoscopically. Type II cysts extend beyond the confines of the larynx and require an external approach. The Type II cysts are further subclassified histologically on the basis of the embryologic tissue of origin: IIa, composed of endoderm only and IIb, containing endodermal and mesodermal elements (epithelium and cartilage) in the wall of the cyst. CONCLUSIONS: A new classification system for congenital laryngeal cysts is proposed on the basis of the extent of the cyst and the embryologic tissue of origin. This classification can help guide the surgeon with initial management and help us better understand the origin of these cysts.

Cysts↗
PubMed1998

A classification tree analysis of selection for discretionary treatment.

OBJECTIVES: To study treatment bias in observational outcomes research, the authors present a nonlinear classification tree model of clinical and psychosocial factors influencing selection for interventional management (lower extremity bypass surgery or angioplasty) for patients with intermittent claudication. METHODS: The study sample includes 532 patients with mild to moderate lower extremity vascular disease, without prior peripheral revascularization procedures or symptoms of disease progression. All patients were enrolled in a prospective outcomes study at the time of an initial referral visit for claudication to one of the 16 Chicago-area vascular surgery offices or clinics in 1993-95. The influence of baseline sociodemographic, clinical, and patient self-reported health status data on subsequent treatment is analyzed. Study variables were derived from lower extremity blood flow records and patient questionnaires. Follow-up home health visits were used to ascertain the frequency of lower extremity revascularization procedures within 6 months of study enrollment. Hierarchically optimal classification tree analysis (CTA) was used to obtain a nonlinear model of treatment selection. The model retains attributes with the highest sensitivity at each node based on cutpoints that maximize classification accuracy. Experimentwise Type I error is ensured at P < 0.05 by the Bonferroni method and jackknife validity analysis is used to assess model stability. RESULTS: Seventy-one of 532 patients (13.3%) underwent interventional procedures within 6 months. Ten patient attributes were used in the CTA model, which had an overall classification accuracy of 89.5% (67.6% sensitive and 92.9% specific), achieving 57.7% of the theoretical possible improvement in classification accuracy beyond chance. Eleven model prediction endpoints reflected a 33-fold difference in odds of undergoing lower extremity revascularization. CONCLUSIONS: Initial ankle-brachial index (100%), leg symptom status over the previous six months (89%), self-reported community walking distance (74%) and prior willingness to undergo a lower extremity hospital procedure (39%) were used to classify most patients in the sample. These attributes are critical control variables for a valid observational study of treatment effectiveness.

Angioplasty↗
PubMed1998

Comparison of professional judgment versus an algorithm for nutrition status classification.

OBJECTIVES: The classification of a patient's nutrition status is important for identifying patients who require nutrition care, for designing effective nutrition interventions, and for measuring severity of illness. The objective of this study was to evaluate the reliability and validity of two variants of the Department of Veterans Affairs' nutrition status classification: professional judgment versus an algorithm. METHODS: The study consisted of two phases, both of which included providing a sample of approximately 60 registered dietitians and 60 clinical dietetic technicians with data on 16 (phase I) and 20 (phase II) patients, to which they assigned nutrition statuses using both professional judgment and the algorithm. Improvements in instructions and training were implemented between the two phases. Interrater reliability of the responses was calculated, and content validity was measured by comparing the staff's responses with those of an expert panel. RESULTS: Reliability improved significantly between phases for both professional judgment and the algorithm. Greater reliability and validity were observed with use of the algorithm, by both dietitians and technicians, during both phases. CONCLUSION: Classification of a patient's nutrition status is important in the delivery of cost-effective health care. The Department of Veterans Affairs' nutrition status classification is a good one for assessing nutrition status quickly and reliably, especially when an algorithm is used. The results underscore the advantages of a classification system based on an algorithm when the system is designed to be used by many different staff across multiple facilities.

Adult↗
PubMed2002

An aetiological classification for developmental synostoses at the elbow.

Synostoses at the elbow joint are rare. The literature divides them into three groups based on the nature of bony ankylosis; the commonest are humeroradial synostoses. Approximately 150 cases have been reported. There are 29 reported cases of humeroradioulnar synostosis and five of humeroulnar synostosis. An anatomical classification was previously described for humeroradial synostoses. Due to significant phenotypic variability we believe a classification based solely on anatomical characteristics will in some cases be misleading. No classification exists for humeroradioulnar and humeroulnar synostosis. By re-examining the literature we have produced a combined classification for all elbow synostoses which more accurately predicts causes. Congenital elbow synostoses often cause little functional disability. Treatment by soft tissue release and osteotomy has been attempted, but although range of movement is initially, improved re-ossification is the norm. Investigation is more complicated and may be helped by classification which identifies syndrome association, risk of organ anomaly, and inheritance pattern.

Child↗
PubMed1998

Reliability of a Crohn's disease clinical classification scheme based on disease behavior.

Classification of Crohn's disease (CD) by disease behavior--either inflammatory (INF), fibrostenotic (FS), or fistulizing/perforating (FP)--has been proposed as a means of assisting management decisions and predicting outcomes for subgroup analysis in clinical trials and for making phenotype/genotype associations in molecular genetic studies. Accurate and reproducible classification of CD patient subgroups is of paramount importance in such studies but to be useful, the classification scheme must have good interrater agreement. We sought to assess the interrater agreement associated with the disease-behavior classification scheme of CD. Twelve patients with CD were randomly selected from a database of 964 patients with CD undergoing medical or surgical treatment or both. Clinical details of the 12 cases, along with their radiographs and surgical and pathological reports, were presented to a panel of 20 experts who were asked to classify each case based on the patient's overall disease course (scenario A) and as if the patient were being entered into a clinical trial on that day (scenario B). Calculations of strength of interrater agreement were made and were expressed as the kappa statistic (kappa), with kappa < 0.2 = poor strength of agreement; kappa 0.21 - 0.4 = fair; kappa 0.41 - 0.6 = moderate; kappa 0.61 - 0.8 = good; and kappa 0.81 - 1.0 = very good. Five panel participants did not complete the study, and three clinical vignettes were excluded because of incomplete scoring, leaving a total of 15 panel experts assessing nine cases. Overall interrater agreement was only fair with kappa = 0.353 for scenario A and kappa = 0.291 for scenario B. Interrater agreement was less when only the most straightforward case in each disease category was evaluated. Classification of CD by pattern of disease behavior yields only fair interrater agreement. This raises concerns regarding its applicability, particularly in ongoing studies of genotype/phenotype associations. Further refinement of disease subtypes and clear operational definitions are required.

Adult↗
PubMed2000

The Ljubljana classification: a practical strategy for the diagnosis of laryngeal precancerous lesions.

There is no internationally accepted classification of epithelial hyperplastic laryngeal lesions (EHLL). The majority of current classifications follow criteria similar to those commonly used for cervical epithelial lesions. However, the different etiology of laryngeal cancer and its particular clinical and histologic features necessitate a grading system more appropriate to this region. The Ljubljana classification of EHLL was devised in 1971 to cater to this requirement. Detailed criteria for histologic grading in this classification were formulated by a working group on EHLL of the European Society of Pathology in 1999. The system recognizes four grades: simple and abnormal hyperplasia are benign categories; atypical hyperplasia ("risky" epithelium) is potentially malignant, and carcinoma in situ actually malignant. The main features by which the proposed grading system differs from other classifications are: 1. the distinction between benign and potentially malignant lesions; 2. the positive separation of carcinoma in situ from atypical hyperplasia; 3. the lack of prognostic significance for any surface keratin layer. The eventual outcome of EHLL patients so graded justifies the proposal for separating the lesions into a benign group, showing malignant transformation in only 0.9% of cases, from a potentially malignant group showing malignant transformation in 11% of cases. For diagnostically difficult cases, supplementary techniques such as those using morphometry, immunohistochemical and molecular biology are advised to improve the accuracy of diagnosis and predictions of their biological behavior.

Carcinoma in Situ↗
PubMed2005

A new operative classification of idiopathic scoliosis: a peking union medical college method.

STUDY DESIGN: A retrospective radiographic study on the type of surgically treated idiopathic scoliosis, with a prospective study on the reliability of the type-related fusion guide. OBJECTIVES: To identify and classify surgically treated idiopathic scoliosis, and define its related fusion levels by a new classification system. SUMMARY OF BACKGROUND DATA: Some classification methods for idiopathic scoliosis have been suggested. However, poor intraobserver reproducibility and interobserver reliability were experienced in these studies, and were not appropriate for guiding surgical planning. METHODS: A total of 427 surgically treated idiopathic scoliosis cases were reviewed. Preoperative and postoperative standing anteroposterior, lateral, and preoperative supine side-bending radiograph were analyzed using the Scoliosis Research Society definition of scoliosis and curve apex. The resulting classification was tested for intraobserver reliability and interobserver reliability, and by 6 surgeons. Apical frequencies were determined for each type, and prospective surgical testing of the new type and its related fusion guide was performed. RESULTS: Three major types and 13 subtypes were identified, of which the Peking Union Medical College type I accounted for 56.62%, type II 42.16%, and type III 1.22%. The interobserver reliability testing was 85% (kappa coefficient 0.832), while intraobserver reproducibility was 91% (kappa coefficient 0.898). Each type had its corresponding fusion levels. A prospective study of 152 cases was performed according to the classification. All of these cases were followed over 18 months, and no postoperative decompensation was noted. CONCLUSION: The Peking Union Medical College classification of idiopathic scoliosis is one system to combine each type with its corresponding fusion level, and it had much higher interobserver reliability and intraobserver reproducibility than the King system. Further prospectivestudies would help to clarify and expand this system.

Adolescent↗
PubMed2005

The Modic classification: inter- and intraobserver error in clinical practice.

STUDY DESIGN: A reliability study of the Modic classification. OBJECTIVE: To determine the reliability and reproducibility of the Modic classification for lumbar vertebral marrow changes. SUMMARY OF BACKGROUND DATA: In 1988, Modic et al described two degenerative stages of vertebral marrow and endplate morphology. These were type 1 (inflammatory phase) and type 2 (a fatty phase). Later in 1988, he added a third variety: type 3 where there was marked sclerosis adjacent to the endplates. No formal reliability or reproducibility studies had been performed on this Modic classification. METHODS: This study involved five independent observers of differing spinal experience using the Modic classification to grade 50 sagittal T1- and T2-weighted magnetic resonance imaging scans. The observers repeated the assessment at 3 weeks. Intra- and interobserver reliabilities were assessed using kappa statistics. RESULTS: There were 7 type 1, 40 type 2, 1 type 3, and 2 normal levels. The individual intraobserver agreement was substantial or excellent with kappa values ranging from 0.71 to 1. The overall interobserver agreement was excellent with a kappa value of 0.85. There was complete agreement in 78% of the levels, a difference of one type in 14% and a difference of two or more in 8% of levels. The level of experience of the observer did not correlate with a better score. CONCLUSIONS: We have shown that the classification is both reliable and reproducible. It is simple and easy to apply for observers of varying clinical experience. We therefore recommend its use in clinical research and practice.

Adult↗
PubMed2006

Computer-assisted algorithms improve reliability of King classification and Cobb angle measurement of scoliosis.

STUDY DESIGN: Interobserver and intraobserver reliability study of improved method to evaluate radiographs of patients with scoliosis. OBJECTIVE: To determine the reliability of a computer-assisted measurement protocol for evaluating Cobb angle and King et al classification. SUMMARY OF BACKGROUND DATA: Evaluation of scoliosis radiographs is inherently unreliable because of technical and human judgmental errors. Objective, computer-assisted evaluation tools may improve reliability. METHODS: Posteroanterior preoperative radiographic images of 27 patients with adolescent idiopathic scoliosis were each displayed on a computer screen. They were marked 3 times in random sequence by each of 5 evaluators (observers) who marked 70 standardized points on the vertebrae and sacrum in each radiograph. A computer program (Spine 2002;27:2801-5) that identified curves, calculated Cobb angles, and generated the King et al classification automatically analyzed coordinates of these points. The interobserver and intraobserver variability of the Cobb angle and King et al classification evaluations were quantified and compared with values obtained by unassisted observers. RESULTS: Average Cobb angle intraobserver standard deviation was 2.0 degrees for both the thoracic and lumbar curves (range 0.1 to 8.3 degrees for different curves). Interobserver reliability was 2.5 degrees for thoracic curves and 2.6 degrees for lumbar curves. Among the 5 observers, there was an inverse relationship between repeatability and time spent marking images, and no correlation with image quality or curve magnitude. Kappa values for the variability of the King et al classification averaged 0.85 (intraobserver). CONCLUSIONS: Variability of Cobb measurements compares favorably with previously published series. The classification was more reliable than achieved by unassisted observers evaluating the same radiographs. The same principles may be applicable to other radiographic measurement and evaluation procedures.

Algorithms↗