Nonparametric estimation of residual variance revisited

SUMMARY Several difference-based estimators of residual variance are compared for finite sample size. Since the introduction of a rather simple estimator by Gasser, Sroka & Jennen-Steinmetz (1986) other proposals have been made. Here the one given by Hall, Kay & Titterington (1990) is of particular interest. It minimizes the asymptotic variance. Unfortunately it has severe problems with finite sample bias, and the estimator of Gasser et al. (1986) proves still to be a good choice. A new estimator is introduced, compromising between bias and varianc

Prediction of Distant Metastasis in Head Neck Cancer Patients: Implications for Induction Chemotherapy and Pre-treatment Staging?

Background and Purpose: : Intensity modulated radiation therapy (IMRT) combined treatment approaches, surgical and radiodiagnostic advances, respectively, lead to improved local-regional control in head neck cancer (HNC). With increasing local-regional control, distant metastases (DM) become more meaningful. In some trials without concomitant chemotherapy, induction chemotherapy (IC) resulted in an absolute reduction of DM by ~10-15%. In order to define a more efficient selection of patients at risk for DM with respect to IC and M-staging, we analysed our patients treated by contemporary standards. Patients and Methods: : Between 1/2002 to 12/2007, 409 HNC patients were treated with IMRT; 303/409 (74%) underwent definitive, 106 (26%) postoperative IMRT. The mean/median follow-up was 23/20 months (3-72). 70% tolerated 4-7, 9% 1-3 cycles of simultaneous cisplatin. Treatment followed a prospectively designed protocol. In a previous study with 172 HNC IMRT patients, gross tumor volume (GTV) was found the strongest predictor for local-regional control. In the current study, this criterion has been prospectively tested for DM. Numbers needed to treat were calculated for IC. Results: : DM developed in 28/399 (7%) patients; 10 presented initially with DM (total 38/409). In 13/28 (46%), DM remained the only manifestation of disease. GTV was the strongest predictor for DM (p 70 cc; only 6 of them (6/73, 8%) developed isolated DM. Conclusion: : GTV was the most significant predictor for DM, that could guide selective pre-treatment M-staging. The subgroup with isolated DM in the high risk group, that could benefit from IC, is smal

Der Body Mass Index als Entscheidungsgrundlage für medizinisch indizierte Brustreduktionen

Summary: PURPOSE: Breast reduction is a highly emotional theme and bears conflicting interest groups: (1) women who are suffering from symptomatic macromastia and therefore would wish to have their breast reduction paid by the insurers, irrespective of the amount of resection weight, (2) the insurance companies, who are ready to cover only really medically indicated operations and due to a lack of objective parameters often apply the very strict, arbitrary criterium for a minimum resection weight of 500g per breast, and (3) the surgeons, who try to provide a fair, scientific basis for the differentiation between cosmetic and reconstructive indications for breast reductions for the sake of both the patients and the insurance parties. Concerned about such a generalizing rule, we undertook a retrospective review of our patients' charts with both cosmetic and reconstructive indications to judge the available, more-level minimum resection weight standards and see wether they were appropriate to use, or to provide an objective and measurable guideline for a scaled amount of breast reduction beyond the 500 g-resection-rule, adapted to the individual woman's body proportions. METHODS: 136 women could be included in the study. The resection weight was recorded and correlated to various parameters of the body proportions such as weight, height, the body mass index (BMI) and the body surface. The results were compared to the available minimum resection weight rules. RESULTS: The resection weight ranged from 55 to 1530g (mean, 450g ± 266g; median, 406g). Overweight was present in 36% of all patients, whereas obesity was present in 7.5 % of women. The mean BMI was 25.1 kg/m2. Of the twenty-four patients (18%), who were classified a priori as having a cosmetic indication, 4 (18%) had more than 500g breast tissue resected bilaterally. On the other hand, in 55% of reconstructive patients less than the predicted 500g of breast tissue had been resected. From all examined parameters the BMI had the highest correlation to the resected mean breast tissue (r = 0.64, p ≤ 0.001). DISCUSSION: Our retrospective review thus showed that with an arbitrary 500g breast resection-rule all women beyond the mean values for weight and height were clearly put at a disadvantage. Also not completely solving this problem are the already available, more objective guidelines for graded minimum resection weight recommendations which have relied on the body weight or the body surface area, parameters that both had a much lower correlation to the resected breast tissue in the patient group than the BMI. We therefore suggest using the BMI as the basis for a graded, more-level weight resection standard for reconstructive breast reductions. This algorithm is related solely to objectifying data and thus avoids biases from empirically derived data or hardly quantifiable breast (or obesity) related pain syndromes, and respects all the different body builds of wome

A body mass index related scale for reconstructive breast reduction

Breast reduction is a highly emotional topic, involving three conflicting interests: (a) women suffering from symptomatic macromastia, (b) health insurance companies, and (c) surgeons. Many insurance companies, including those in Austria, cover (if at all) only breast reductions with a minimum resection weight of 500g per breast, irrespective of the physical build of the woman involved. We retrospectively reviewed 136 patients' charts from both cosmetic and reconstructive breast reduction operations and compared the breast resection weight to various parameters of body proportions such as height, weight, body mass index (BMI), and body surface area to determine the parameter best correlated to the weight of breast tissue resected. From this we developed a graded scale for guiding future operations irrespective of a woman's body build. The resection weight ranged from 55 to 1530g (mean 450±266, median 406); mean BMI was 25.1. The arbitrary 500g breast resection rule discriminates against women of nonaverage weight or height: of 24 patients (18%) with a cosmetic indication 4 had more than 500g breast tissue resected bilaterally, while in 62 reconstructive patients (46%) less than the arbitrary 500g breast tissue was resected. The parameter best correlated to the mean weight of breast tissue resected (sum of both breasts) was BMI. We therefore suggest using the BMI as the basis for a graded weight resection guideline for reconstructive breast reductions. The BMI-based scale treats equally women of all types of body build. In women with a BMI greater than 30 (classified as adiposity) we recommend that breast reduction be postponed, and a general body weight reduction program be undertaken for the sake of a higher impact on general well-bein

Renal dimensions measured by ultrasonography in children: variations as a function of the imaging plane and patient position

The purpose of this study was to determine the effect of patient positioning on sonographic renal measurements and to test if the patient position alters the three-dimensional shape of the kidneys. The maximum longitudinal renal length and transverse renal width and depth were measured in the supine and prone position in 100 children (200 kidneys). Age ranged from 6 months to 16 years (mean age 5 years). The results were compared for statistically significant differences. The maximum measured longitudinal renal length was statistically significantly larger in the supine than in the prone position (supine position, left: 8.0cm; right: 7.7cm; prone position, left: 7.9cm, right: 7.6cm; P0.001) and renal volume (P>0.001) in the supine vs. prone positions. Our results show that position-induced reshaping of the kidneys is unlikely to be responsible for the discrepancy in maximum longitudinal renal measurements comparing supine with prone positions. Position-dependent changes in the degree of filling of the renal calyces and pelvis as well as errors in caliper distance measurements for the different scan depths (supine vs. prone) are more likely to be responsible for the encountered differences. Consequently, we recommend to add prone renal length measurements in addition to the supine measurements. In follow-up examinations, renal length measurements should only be compared that have been collected in the same patient positio

The Severity of Injury and the Extent of Hemorrhagic Shock Predict the Incidence of Infectious Complications in Trauma Patients

Abstract : Background: : Trauma patients are at high risk of developing systemic inflammatory response syndrome (SIRS) and infections. The aim of this study was to evaluate the influence of the severity of injury and the extent of hemorrhagic shock at admission on the incidence of SIRS, infection and septic complications. Methods: : A total of 972 patients who had an injury severity score (ISS) of ≥ 17, survived more than 72 h, and were admitted to a level I trauma center within 24 h after trauma were included in this retrospective analysis. SIRS, sepsis and infection rates were measured in patientswith different severities of injury as assessed by ISS, or with various degrees of hemorrhagic shock according to ATLS® guidelines, andwere compared using both uni- and multivariate analysis. Results: : Infection rates and septic complications increase significantly (p < 0.001) with higher ISS. Severe hemorrhagic shock on admission is associated with a higher rate of infection (72.8%) and septic complications (43.2%) compared to mild hemorrhagic shock (43.4%, p < 0.001 and 21.7%, p < 0.001, respectively). Conclusion: : The severity of injury and the severity of hemorrhagic shock are risk factors for infectious and septic complications. Early diagnostic and adequate therapeutic work up with planned early "second look" interventions in such high-risk patients may help to reduce these common posttraumatic complication

A Useful Radiologic Method for Preoperative Joint-line Determination in Revision Total Knee Arthroplasty

Intraoperative joint-line determination during revision TKA is difficult and no method exists to plan the position preoperatively. Two questions need to be answered: to which extent does the joint line differ from its anatomic position after revision TKA if it has only been determined intraoperatively, and can the joint line be calculated preoperatively based on the transepicondylar width. Of 22 consecutive patients with complete preoperative (before and after primary TKA) and postoperative (after revision TKA) radiograph documentation, the joint-line position was measured on plane radiographs using the medial epicondyle as a reference. On another set of 45 consecutive patients with no knee disorders other than meniscal lesions, the transepicondylar axis width (TEAW) and the perpendicular distance from the medial and lateral epicondyles to the joint line were measured twice by two independent observers on plane AP radiographs of the knee. Significant joint-line alterations were observed after primary and revision TKA, implicating that a method for preoperative planning is needed. Because a linear correlation between the TEAW and the perpendicular distance from the epicondyles to the joint-line tangent was found, the ratio is useful to calculate the true joint-line position from the TEAW before revision TKA. Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidenc

Long-term neuromuscular sequelae of critical illness

In this observational study, we analyzed the long-term neuromuscular deficits of survivors of critical illness. Intensive care unit-acquired muscular weakness (ICU-AW) is a very common complication of critical illness. Critical illness polyneuropathy (CIP) and critical illness myopathy (CIM) are two main contributors to ICU-AW. ICU-AW is associated with an increased mortality and leads to rehabilitation problems. However, the long-term outcome of ICU-AW and factors influencing it are not well known. We analyzed the medical records of 490 survivors of critical illness, aged 18-75years and located in the area of the study center. Intensive care unit (ICU) survivors with comorbidities that might influence neuromuscular follow-up examinations, muscle strength, or results of nerve conduction studies, such as renal or hepatic insufficiency, diabetes mellitus, or vitamin deficiency were excluded. A total of 51 patients were finally included in the study. Six to 24months after discharge from the ICU, we measured the Medical Research Council (MRC) sum score, the Overall Disability Sum score (ODSS), and also performed nerve conduction studies and EMG. For all ICU survivors, the median MRC sum score was 60 (range 47-60) and the median ODSS score was 0 (range 0-8). CIP was diagnosed in 21 patients (41%). No patient was diagnosed with CIM. Patients with diagnosis of CIP showed a higher median ODSS scores 1 (range 0-8) versus 0 (range 0-5); p<0.001 and lower median MRC sum scores 56 (range 47-60) versus 60 (range 58-60); p<0.001. The three main outcome variables MRC sum score, ODSS score and diagnosis of CIP were not related to age, gender, or diagnosis of sepsis. The MRC sum score (r=−0.33; p=0.02) and the ODSS score (r=0.31; p=0.029) were correlated with the APACHE score. There was a trend for an increased APACHE score in patients with diagnosis of CIP 19 (range 6-33) versus 16.5 (range 6-28); p=0.065. Patients with the diagnosis of CIP had more days of ICU treatment 11days (range 2-74) versus 4days (range 1-61); p=0.015, and had more days of ventilator support 8days (range 1-59) versus 2days (range 1-46); p=0.006. The MRC sum score and the ODSS score were correlated with the days of ICU treatment and with the days of ventilator support. The neuromuscular long-term consequences of critical illness were not severe in our study population. As patients with concomitant diseases and old patients were excluded from this study the result of an overall favorable prognosis of ICU-acquired weakness may not be true for other patient's case-mix. Risk factors for the development of long-term critical illness neuropathy are duration of ICU treatment, duration of ventilator support, and a high APACHE score, but not diagnosis of sepsis. Although ICU-AW can be serious complication of ICU treatment, this should not influence therapeutic decisions, given its favorable long-term prognosis, at least in relatively young patients with no concomitant disease