In vitro biomechanical comparison of plate-rod combination and interlocking nail constructs in a canine tibial gap fracture model

INHALTSVERZEICHNIS Deckblatt \- Impressum persönlicher Dank Inhaltsverzeichnis 1 Einleitung 1 2 Literaturübersicht 11 3 Eigene Untersuchungen 37 4 Diskussion 69 5 Zusammenfassung 93 6 Summary 95 7 Klinisches Fallbeispiel 97 8 Literaturverzeichnis 103 9 Anhang 125 9.1 Abkürzungsverzeichnis 125 9.2 Begriffserklärungen 126 9.3 Formelverzeichnis 129 9.4 Bezugsquellenverzeichnis 131 9.5 Meßwerte 133 9.6 Abbildungs-, Grafiken- und Tabellenverzeichnis 140 DanksagungEine vier Jahre alte Golden-Retriever-Hündin (39,8 kg, sterilisiert) wurde wegen hochgradiger Lahmheit und einer Hautwunde am linken Hinterlauf vorgestellt. Kurz vorher war die Hündin von einem Auto angefahren worden. Nach stabilisierender Notfallbehandlung, Reinigung der Hautwunde (2 cm Durchmesser, geringgradig verschmutzt, auf Höhe der Tibia-Diaphyse) und Einleitung einer intravenösen Antibiose mit Cefazolin wurden Röntgenaufnahmen des Brustkorbes (ohne besondern Befund = o.b.B.), Abdomens (o.b.B.) sowie des linken Hinterlaufes angefertigt. Die Verletzung am Hinterlauf konnte als offene (Typ II) diaphysäre Trümmerfraktur der linken Tibia und Fibula klassifiziert werden (Abb.33). Es wurde beschlossen, die Fraktur mittels interner Fixierung zu versorgen, da die Hündin vom Besitzer als sehr aktiv und schwer ruhigstellbar charakterisiert wurde. Außerdem war der Verschmutzungsgrad der Fraktur nicht sehr groß und damit das Risiko einer Wundinfektion relativ gering. Ein medialer Zugang zur Tibia wurde durchgeführt und die Hautwunde und das Frakturgebiet ausgiebig gereinigt. Schmale, lose Knochenfragmente wurden aus der Wunde entfernt, weiter zerkleinert und in einem blutgetränkten Tupfer aufbewahrt. Die Versorgung der Fraktur geschah mit einem 11-06-140-02-2,7 mm Verriegelungsnagel. Wiederholte Spülungen mit steriler Kochsalzlösung wurden durchgeführt, die Knochenspäne in das Frakturgebiet wieder eingesetzt und die Wunde geschlossen. Bei Manipulation nach der Implantation des VN erwies sich die Frakturversorgung als stabil. Abbildung 34 zeigt die postoperativen Röntgenbilder. Obwohl keine anatomische Rekonstruktion möglich war, wird ersichtlich, daß eine gute Ausrichtung der Fraktur erreicht wurde und mit dem Verriegelungsnagel eine angemessene Wahl zur Frakturversorgung getroffen worden war. Alle Schrauben waren in korrekter Weise plaziert worden.The purpose of this study was to compare the biomechanical properties of an Interlocking Nail (ILN) and a Plate-Rod-Combination (PRC) in a canine comminuted fracture model. The hypotheses were that construct torsional and compressive compliances will be greater with ILN than with PRC and that construct bending compliance will be similar for both fixation devices. Twelve canine tibial pairs of similar size were used. Three groups were formed (n=4/group). The group size was determined in a pilot study. In each pair, one tibia was instrumented with a 160 mm x 6 mm ILN, using four 2.7 mm screws. The contralateral tibia was stabilized with a 4 mm Steinmann pin, combined with an 11-hole, 3.5 mm limited contact - dynamic compression plate. To mimic a comminuted fracture, a 10 mm mid-diaphyseal defect was created. Four paired specimens were cyclically loaded in torsion (±5 Nm), compression (167.58 N), or bending (3.5 Nm). Construct compliances were determined at the 10th cycle, then compared within and between constructs using two-factor ANOVA and Tukey's post-hoc tests (torsion, compression). Bending tests were compared using a paired student�s t-test. Finally, the samples were tested to failure. The load to failure was compared using a paired student�s t-test. The significance level was set at p<0.05 for all tests. The mode of failure was reported qualitatively. Compliance curves for the ILN constructs were consistently bilinear in both torsion and compression. In torsion, the initial compliance between the constructs was significantly greater than the secondary compliance (p<0.001). Importantly, the maximum mean torsional angle with ILN was close to 35°. Initial compliances were also greater in the ILN in comparison to the PRC constructs in compression (p<0.005). Conversely, in either torsion or compression, there were no significant differences in secondary compliances between ILN and PRC constructs. Finally, bending compliance curves did not show the bilinear appearance found in torsion or compression. Moreover, ILN and PRC construct compliances were not significantly different in bending. During failure testing, the ILN was more prone to deformation than the PRC. The results of this study demonstrate that in a comminuted fracture model the combination of a bone plate and an IM pin provides a significantly more rigid fixation method than an ILN in torsion. This finding may result from a mismatch between the screw and nail hole diameter as well as deformation of the screw threads and the nail hole under torsional loads. Clinically, by improving tibial fracture repair stability, plate-rod-combinations may reduce post-operative morbidity and promote faster return to limb function, compared to an interlocking nail

A statistical gap-filling method to interpolate global monthly surface ocean carbon dioxide data

We have developed a statistical gap-filling method adapted to the specific coverage and prop-erties of observed fugacity of surface ocean CO2(fCO2). We have used this method to interpolate the Sur-face Ocean CO2Atlas (SOCAT) v2 database on a 2.5832.58 global grid (south of 708N) for 1985–2011 atmonthly resolution. The method combines a spatial interpolation based on a ‘‘radius of influence’’ to deter-mine nearby similar fCO2values with temporal harmonic and cubic spline curve-fitting, and also fits long-term trends and seasonal cycles. Interannual variability is established using deviations of observations fromthe fitted trends and seasonal cycles. An uncertainty is computed for all interpolated values based on thespatial and temporal range of the interpolation. Tests of the method using model data show that it performsas well as or better than previous regional interpolation methods, but in addition it provides a near-globaland interannual coverage

Transcellular blood-brain barrier disruption in malaria-induced reversible brain edema.

Brain swelling occurs in cerebral malaria (CM) and may either reverse or result in fatal outcome. It is currently unknown how brain swelling in CM reverses, as brain swelling at the acute stage is difficult to study in humans and animal models with reliable induction of reversible edema are not known. In this study, we show that reversible brain swelling in experimental murine CM can be induced reliably after single vaccination with radiation-attenuated sporozoites as proven by in vivo high-field magnetic resonance imaging. Our results provide evidence that brain swelling results from transcellular blood-brain barrier disruption (BBBD), as revealed by electron microscopy. This mechanism enables reversal of brain swelling but does not prevent persistent focal brain damage, evidenced by microhemorrhages, in areas of most severe BBBD. In adult CM patients magnetic resonance imaging demonstrate microhemorrhages in more than one third of patients with reversible edema, emphasizing similarities of the experimental model and human disease. Our data suggest that targeting transcellular BBBD may represent a promising adjunct therapeutic approach to reduce edema and may improve neurological outcome

Disputatio Inauguralis Iuridica Ad Clementinam Saepe Contingit. De Verborum Significatione Delineationem Processus Summarii Exhibens

Quam ... In Illustri Academia Ernestina Praeside Dn. Hermanno Zollio, ICto ... Publice Eruditorum disquisitioni submittit Gerhardus Fridericus Pfeil/ Petrihaga-Mindensis ... Ad Diem 6. Martii 1696.Vorlageform des Erscheinungsvermerks: Rinthelii, Typis Hermanni Augustini Enax, Academ. Typogr. MDCXCVI