Influencing factors on the length of stay in lumbar spine surgery: analysis of the German spine registry

INTRODUCTION Spinal disc herniation, lumbar spinal stenosis and spondylolisthesis are known to be leading causes of lumbar back pain. The cost of low back pain management and related operations are continuously increasing in the healthcare sector. There are many studies regarding complications after spine surgery but little is known about the factors predicting the length of stay in hospital. The purpose of this study was to identify these factors in lumbar spine surgery in order to adapt the postoperative treatment. MATERIAL AND METHODS The current study was carried out as a post hoc analysis on the basis of the German spine registry. Patients who underwent lumbar spine surgery by posterior surgical access and with posterior fusion and/or rigid stabilization, whereby procedures with dynamic stabilization were excluded. Patient characteristics were tested for association with length of stay (LOS) using bivariate and multivariate analyses. RESULTS A total of 356 patients met the inclusion criteria. The average age of all patients was 64.6 years and the mean LOS was 11.9 ± 6.0 days with a range of 2-44 days. Independent factors that were influencing LOS were increased age at the time of surgery, higher body mass index, male gender, blood transfusion of 1-2 erythrocyte concentrates and the presence of surgical complications. CONCLUSION Identification of predictive factors for prolonged LOS may allow for estimation of patient hospitalization time and for optimization of postoperative care. In individual cases this may result of a reduction in the LOS.

On The Breakdown Properties of some Multivariate M-Functionals

For probability distributions on ℝq, a detailed study of the breakdown properties of some multivariate M-functionals related to Tyler's [Ann. Statist. 15 (1987) 234] ‘distribution-free’ M-functional of scatter is given. These include a symmetrized version of Tyler's M-functional of scatter, and the multivariate t M-functionals of location and scatter. It is shown that for ‘smooth’ distributions, the (contamination) breakdown point of Tyler's M-functional of scatter and of its symmetrized version are 1/q and inline image, respectively. For the multivariate t M-functional which arises from the maximum likelihood estimate for the parameters of an elliptical t distribution on ν ≥ 1 degrees of freedom the breakdown point at smooth distributions is 1/(q + ν). Breakdown points are also obtained for general distributions, including empirical distributions. Finally, the sources of breakdown are investigated. It turns out that breakdown can only be caused by contaminating distributions that are concentrated near low-dimensional subspaces.

New Algorithms for M-Estimation of Multivariate Scatter and Location

We present new algorithms for M-estimators of multivariate scatter and location and for symmetrized M-estimators of multivariate scatter. The new algorithms are considerably faster than currently used fixed-point and related algorithms. The main idea is to utilize a second order Taylor expansion of the target functional and to devise a partial Newton-Raphson procedure. In connection with symmetrized M-estimators we work with incomplete U-statistics to accelerate our procedures initially.

Influence of prosthesis type and retention mechanism on complications with fixed implant-supported prostheses: a systematic review applying multivariate analyses

PURPOSE To identify the influence of fixed prosthesis type on biologic and technical complication rates in the context of screw versus cement retention. Furthermore, a multivariate analysis was conducted to determine which factors, when considered together, influence the complication and failure rates of fixed implant-supported prostheses. MATERIALS AND METHODS Electronic searches of MEDLINE (PubMed), EMBASE, and the Cochrane Library were conducted. Selected inclusion and exclusion criteria were used to limit the search. Data were analyzed statistically with simple and multivariate random-effects Poisson regressions. RESULTS Seventy-three articles qualified for inclusion in the study. Screw-retained prostheses showed a tendency toward and significantly more technical complications than cemented prostheses with single crowns and fixed partial prostheses, respectively. Resin chipping and ceramic veneer chipping had high mean event rates, at 10.04 and 8.95 per 100 years, respectively, for full-arch screwed prostheses. For "all fixed prostheses" (prosthesis type not reported or not known), significantly fewer biologic and technical complications were seen with screw retention. Multivariate analysis revealed a significantly greater incidence of technical complications with cemented prostheses. Full-arch prostheses, cantilevered prostheses, and "all fixed prostheses" had significantly higher complication rates than single crowns. A significantly greater incidence of technical and biologic complications was seen with cemented prostheses. CONCLUSION Screw-retained fixed partial prostheses demonstrated a significantly higher rate of technical complications and screw-retained full-arch prostheses demonstrated a notably high rate of veneer chipping. When "all fixed prostheses" were considered, significantly higher rates of technical and biologic complications were seen for cement-retained prostheses. Multivariate Poisson regression analysis failed to show a significant difference between screw- and cement-retained prostheses with respect to the incidence of failure but demonstrated a higher rate of technical and biologic complications for cement-retained prostheses. The incidence of technical complications was more dependent upon prosthesis and retention type than prosthesis or abutment material.

Die Schnell-Copirkunst der Gewerbs-Risse und Zeichnungen : nach den neuesten ... Methoden ...Zum Selbstunterricht ... in Sonntags- und Gewerbsschulen

von Fr. A. W. Netto, königl. Lehrer

Neueste exegetische Methoden

Siegmund Jampel

Vergleichende Versuche über die Wirkung verschiedener Mittel und Methoden zur Bekämpfung der Feldmausplage

Von Dr. Korff