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The reliability of clinical measurements is critical to medical research and clinical practice. Newly proposed methods are assessed in terms of their reliability, which includes their repeatability, intra- and interobserver reproducibility. In general, new methods that provide repeatable and reproducible results are compared with established methods used clinically. This paper describes common statistical methods for assessing reliability and agreement between methods, including the intraclass correlation coefficient, coefficient of variation, Bland-Altman plot, limits of agreement, percent agreement, and the kappa statistic. These methods are more appropriate for estimating reliability than hypothesis testing or simple correlation methods. However, some methods of reliability, especially unscaled ones, do not clearly define the acceptable level of error in real size and unit. The Bland-Altman plot is more useful for method comparison studies as it assesses the relationship between the differences and the magnitude of paired measurements, bias (as mean difference), and degree of agreement (as limits of agreement) between two methods or conditions (e.g., observers). Caution should be used when handling heteroscedasticity of difference between two measurements, employing the means of repeated measurements by method in methods comparison studies, and comparing reliability between different studies. Additionally, independence in the measuring processes, the combined use of different forms of estimating, clear descriptions of the calculations used to produce indices, and clinical acceptability should be emphasized when assessing reliability and method comparison studies.
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Arterovenous malformations(AVVMs) represent the most commonly encountered symptomatic vascular malformations in the field of vascular neurosurgery. Surgically accessible AVMs that present with hemorrhage should be removed to reduce the risk of subsequent hemorrhage. The advance of surgery is based on the size, location and pattern of venous drainage and these anatomic features influence the treatment risk. The author studied the above features for predictor of the surgical resection of AVMs.
Nineteen patients(8 male and 11 female patients) with intracranial AVMs were treated at the Ewha Womans Medical Center between March 1989 and Dec. 1996. The mean age, and sexual ratio, of the pts as will as symptoms, location, feeding arteries, pattern of venous drainage and size of the nidus were studied. AVMs were graded according to the Spetzler and martin grade system. Overall outcome and postoperative results in eighteen patients were evaluated according to Glasgow Outcome SCale(GOS).
The average age at the time of treatment was 30.8 years old(range 4-55 years old). The hemorrhage was the most common symptom, occurring in 15(80%) patients, and 2(10%) patients presented with headache, 195%) patient with seizure, 1(5%) patient with neurological deficit. The feeding arteries were as the followings ; middle cerebral artery 8(42%), anterior cerebral artery 2(10%), posterior cerebral artery 1(5%), The pattern of draining veins were described into superficial and deep ; superficial 9(47%), deep 10(53%), The size of the nidus were as the followings ; small(<3cm) 9(47.5%), medium(3-6cm) 9(47.5%), large(>6cm) 1(5%), The Spetzler-Martin's grade and the outcome according to the grade were as follows ; grade I;3(17%) resulted GOS-5 3 patients, grade II ;5(26%) did GOS-5 6 patients, grade III; 5(26%) did GOS-5 4 patients and GOS-4 1 patient, grade IV;4(21%) did GOS-5 3 patients and GOS-4 1 patient, grade V;1(5%0 did GOS-1 1 patient. Overall, there were no death in surgical treatment, patients, the morbidity value was 2(10%) patients, the remainder were completely cured.
The Spetzler-Martin grade I-IV AVMs were associated with low rates of surgical morbidity and mortality, Therefore, surgery is the best treatment in the these grades.
, Do Sang Cho, Sung Hak Kim, Dong-Been Park , Se Yong Choi, In Suk Yang The advances in surgical techniques and stabilizing devices have made the off-pump coronary artery bypass (OPCAB) popular, and good results have been published. We analyzed the early results of OPCAB performed in our hospital.
Between January 2004 and December 2004, 23 patients underwent OPCAB. There were 14males and 9 females with mean age of 62.6±10.3years. Preoperative diagnoses were unstable angina in 13(57%), acute myocardial infarction in 9(39%), and stable angina in 1(4%). Preoperative angiographic diagnoses were three-vessel disease in 12 (52%), two-vessel disease in 8(35%), one-vessel disease in 1(4%), and left main disease in 2(9%).
The mean number of grafts was 2.6±0.9 per patient. Vessels accessed were left anterior descending artery in 23, diagonal branch in 14, obtuse marginal branch in 9, right coronary artery in 12, and posterior descending artery in 1. Left internal mammary artery were used in 22 patients and bilateral internal mammary arteries were used in 1 patient. There was no operative mortality. Postoperative complications were cerebral vascular accident in 1, postoperative bleeding which required operative management in 2, arrhythmia including atrial fibrillation in 5, and minor operative wound problem in 1. Pre-discharge graft patency was evaluated in 11 patients. One internal mammary artery graft was occluded in 11 internal mammary artery graft evaluated. The patency rate was 91%. Seventeen saphenous vein grafts were patent in 19 saphenous vein grafts and the patency rate was 89%.
Our result of OPCAB is promising and OPCAB is suggested to be the ideal technique with less morbidity and mortality.
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