Fluorochrome Bone Labeling in Sheep

As an efficacy model. thirty-four female Merino sheep underwent transpedicular lumbar interbody fusion with three different materials for augmentation of the spine. Fluorochrome analysis was used to evaluate differences in bone deposition and fusion processes between the three study groups. During the post-operative follow-up period ofeight weeks, the fluorescent dyes xylenol orange. calcein green, and doxyeycline yellow were given at two, four. and six weeks, respectively. All dyes were administered intravenously after sedation with xylazine. The objective of this paper is to provide a methodical description of preparation quality control, administration, efficacy, and observed adverse events from the use of these bone labels in sheep.Both xylenol orange and calcein green dyes provided satisfying results but doxycyeline yellow led to only weak fluorescence in the first ten animals. Consequently, higher dosing was introduced to obtain bright bands in the histological sections. Also, during administration of doxycyeline yellow, mild to severe adverse events occasionally occured: Eight of the first ten sheep suffered from respiratory distress, and in severe cases several stopped breathing, thus requiring immediate intervention. Minimizing the sedative dose and elongating the sedation/doxycycline administration interval were effective changes to the original procedure. We conclude that these adverse events may have been caused by too high a close of sedative, as well as a drug interaction between xylazine and doxycycline yellow

Recombinant human Bone Morphogenetic Protein-7 (rhBMP-7, rhOP-1) enables the Transpedicular Intercorporal Spondylodesis in the Sheep’s Spine

EINFÜHRUNG: Bisherige Methoden der Behandlung von Wirbelkörperfrakturen machten ein kombiniertes Vorgehen aus anteriorem und posteriorem Zugang zum frakturierten Wirbelkörper erforderlich, um zwei Dinge zu ermöglichen: die Stabilisierung der hinteren Säule durch einen Fixateur interne und die Aufrichtung und Abstützung des gesinterten Wirbels durch Cage-Interposition, Verplattung oder autologe trikortikale Spantransplantation vom Beckenkamm zur Erhöhung der axialen Belastbarkeit im frakturierten Wirbelsäulensegment. Ein bereits in den 80er Jahren entstandenes Konzept eines solitären dorsalen Vorgehens mit transpedikulärem Zugang zur Behandlung der ventralen Säule mittels autologer Spongiosa und dem Vorteil einer verminderten Morbidität durch den Wegfall des zusätzlichen ventralen Vorgehens scheiterte an der fehlenden axialen Belastungsstabilität. Wir testeten im Schafsmodell ein modifiziertes dorsales transpedikuläres Verfahren und untersuchten die Effizienz eines rhOP-1-Hydroxylapatit-Zement-Gemisches gegenüber transplantierter Spongiosa und Hydroxylapatit-Zement hinsichtlich seiner Eignung zur Abstützung der vorderen Säule. METHODIK: Es wurden 36 Schafe einer operativen Verblockung der Lendenwirbel 4-6 mittels Fixateur interne unterzogen und in drei Gruppen zu je 12 Tieren eingeteilt. In Gruppe 1 diente autologe Beckenkammspongiosa zur transpedikulären Auffüllung des pedikuloskopisch ausgeräumten Zwischenwirbelraumes L4/5, in Gruppe 2 wurde der Defekt durch Hydroxylapatit-Zement überbrückt und in Gruppe 3 durch Hydroxylapatit-Zement mit darin mikroverkapseltem rhOP-1. Die ersten beiden Tiere der ersten Gruppe mußten wegen einer primären postoperativen Paraplegie der hinteren Extremitäten getötet werden, so daß in dieser Gruppe noch zehn Tiere für die kommenden Untersuchungen verblieben. Nach 8 postoperativen Wochen wurden die Tiere getötet und die seit der Operation stattgefundenen Veränderungen im aufgefüllten Zwischenwirbelraum L4/5 röntgenologisch, makromorphometrisch und histologisch verglichen. ERGEBNISSE: In Gruppe 1 zeigte sich in einem von zehn Fällen eine einseitige knöcherne Durchbauung, in acht der zehn Fälle eine über das ursprüngliche Niveau der Wirbelkörperendplatten hinausreichende Knochenneubildung oder zumindest Spongiosaintegration, es traten keine Entzündungszeichen in dieser Gruppe auf. In Gruppe 2 wurden eine unilaterale und eine bilaterale Wirbelkörperfusion gefunden, die übrigen zehn Schafe wiesen eine deutliche Zementresorption und –fragmentierung mit steriler Entzündungsreaktion und Osteolysen in vier Fällen auf. Charakteristisch war eine horizontal verlaufende Bruchlinie im intervertebralen Anteil der Zementplombe, die in allen Präparaten zu finden, im Falle der Fusionen allerdings durch Knochenbrücken unterbrochen war. Gruppe 3 präsentierte in vier Fällen unilaterale und in sechs Fällen bilaterale Fusionen, selbst die beiden Präparate ohne Fusion zeichneten sich durch deutliche Knochenneubildung und fehlende Zementresorption oder –fragmentierung bei auch hier vorhandener horizontaler Plombenbruchlinie aus, es fanden sich keine osteolytisch-entzündlichen Veränderungen. DISKUSSION: Die rhOP-1-Hydroxylapatit-Zement-Gruppe erwies sich mit zehn erfolgreichen Fusionen ohne Entzündungsreaktionen somit als deutlich überlegen im Vergleich mit transplantierter Spongiosa (eine Fusion, kein Entzündungsfall) und Hydroxylapatit-Zement ohne rhOP-1 (zwei Fusionen, vier Entzündungsfälle). Die in Gruppe 2 und 3 beobachtete horizontale Bruchlinie in der Zementplombe rührte von einer frühen postoperativen Scherkraftbelastung auf den Zwischenwirbelraum L4/5 und konnte in der dritten Gruppe dank der osteoinduktiven Wirkung des rhOP-1 besser durchbaut werden als in der Hydroxylapatit-Zement-Gruppe ohne rhOP-1, in der die alleinige osteokonduktive Wirkung des Knochenzements eine rasche Wirbelkörperfusion nicht herbeiführen konnte. Stattdessen trat in einigen Fällen trotz primärer axialer Belastungsstabilität des Zementes wegen der fehlenden beschleunigten Biointegration des Hydroxylapatits eine deutliche Zementplombenfragmentierung mit nachfolgender steriler Entzündungsreaktion auf. ZUSAMMENFASSUNG: Es konnte also unter Vermeidung eines zusätzlichen ventralen Vorgehens mit einem transpedikulären dorsalen Verfahren mittels einer Kombination aus primär axial belastungsstabilem Hydroxylapatit-Zement und osteoinduktiv wirksamem rhOP-1 in zehn von zwölf Fällen und damit signifikant häufiger als mit den Vergleichsverfahren nach acht postoperativen Wochen eine Wirbelkörperfusion im Schafsmodell herbeigeführt werden.INTRODUCTION: Methods for the treatment of thoracolumbar burst fractures usually combine anterior with posterior approaches to the fractured vertebra to provide two features: stabilization of the posterior column by dorsal instrumentation with an internal fixator and long-term correction of the loss of height in the sagittal profile by cage interposition, anterior plating systems or autologous tricortical strut-graft from the iliac crest to increase axial load bearing capacities in the fractured vertebra. In the eighties, a concept was developed to treat the anterior column with autologous bone by a transpedicular approach. The great advantage of this method was the reduced morbidity with the avoidance of an additional anterior approach to the injured vertebra. Unfortunately, autograft could not provide sufficient stability for axial loading. We tested a modified dorsal transpedicular procedure in sheep and investigated the efficacy of a rhOP-1 enhanced hydroxyapatite cement versus transplanted autologous bone and hydroxyapatite cement as to providing sufficient stability for the anterior column. METHODS: 36 sheep underwent posterior lumbar instrumentation from L4 to L6, transpedicular removal of the intervertebral disc L4/5 and transpedicular augmentation with either autologous bone (group 1), hydroxyapatite cement (group 2) or rhOP-1 enhanced hydroxyapatite cement (group 3). In the first group, ten cases could be evaluated after the first two animals had to be sacrificed due to postoperative paraplegia of the dorsal limbs. Groups 2 and 3 consisted of 12 animals each. The sheep were sacrificed at eight weeks post-op, and the explanted spine segments L4-6 were examined radiologically, makromorphometrically and histologically. RESULTS: In the first group, unilateral osseous bridging over the intervertebral gap was seen in 1/10 cases, 8/10 cases showed new bone formation exceeding the genuine vertebral end plate or – at least – bony integration of the autograft. No inflammatory reactions were seen. The second group presented an unilateral and a bilateral vertebral fusion, 10/12 cases showed gross resorption and cement fragmentation with osteolysis and sterile inflammatory reactions in four cases. Characteristically, a horizontal fracture line could be observed in the intervertebral part of the cement, discontinuous only in the two fused cases because of bony bridging. In the third group, successful vertebral fusion could be found in 10/12 cases (4 unilateral, 6 bilateral), even the remaining two specimen witnessed high-level bone formation and a lack of cement resorption or fragmentation, but showed the horizontal fracture line, as well. No osteolytic or inflammatory reactions were found. DISCUSSION: The rh-OP-1 enhanced hydroxyapatite cement with 10/12 fusions and no inflammatory reactions was far superior to autograft (1/10 fusion, no inflammatory reactions) and hydroxyapatite alone (2/12 fusions, 4 cases of inflammatory reactions). The horizontal fracture line described in group 2 and 3 resulted from early postoperative sheer forces. Due to its osteoinductive effects, rhOP-1 accelerated biointegration of the cement, whereas the osteoconductive effects of the hydroxyapatite cement alone could not prevent from fragmentation, resorption of the cement and inflammatory reaction despite the cement’s primary stability for axial loading. CONCLUSION: Transpedicular lumbar interbody fusion (TLIF) with a composite of primarily stable axial load bearing hydroxyapatite cement and osteoinductive rhOP-1 showed successful fusion in 10/12 cases at eight weeks post-op in a sheep model and avoided the morbidity of an additional anterior approach to the injured vertebra along with the complications of harvesting iliac crest bone

Demineralized bone matrix versus autogenous bone graft for thoracolumbar anterior single-level interbody fusion

Purpose: In thoracolumbar fracture treatment, autogenous iliac crest bone grafting (ICBG) is the standard procedure to achieve anterior single-level fusion. To avoid associated problems of graft harvesting, intervertebral cages are an alternative, but cannot provide biological fusion. Therefore, investigations on fusion-enhancing adjuncts to cages are performed to find biomaterials with biological features comparable to bone grafts. This study was initiated to compare the results of demineralized bone matrix (DBM putty) plus cage vs. ICBG in anterior fusion procedures for thoracolumbar fractures.Methods: Thirty patients underwent posterior bisegmental instrumentation and anterior stabilization by (I) titanium cage with DBM putty (n=15), or (II) autogenous ICBG (n=15).Results: After nine months, biological fusion occurred in 80% and 57% (p≈0.24), respectively. Extent of clinical recovery was 82.5%±17.3% vs. 80.4%±12.9% (p≈0.90). Loss of kyphosis correction amounted to -1.4°±2.1° vs. -1.6°±4.1° (p≈0.91).Conclusions: Fracture treatment with DBM plus titanium cage showed promising 9-months-results in this pilot study on 30 individuals

Resource Consumption and Remuneration Aspects in Navigated Screw Fixation Procedures with or without Additional Sacroplasty for Fragility Fractures of the Sacrum—A Prospective Clinical Study

Surgical treatment for sacral fragility fractures using navigation-assisted screw fixation (NSF) is a modern, technically demanding procedure. Additional sacroplasty (ASP) has been shown to provide only insignificant clinical benefits for patients. This investigation highlights procedural economic aspects and evaluates results with regard to resource scarcity in order to be able to decide, whether ASP has a justification in NSF procedures beyond clinical aspects. From February 2011 to May 2017, all individuals with sacral fragility fractures surgically treated using 3D-fluoroscopy for NSF (n = 26) or NSF + ASP (n = 26) were enrolled. Outcome parameters were operative time, 3D-/2D-radiation dose, 2D-fluoroscopy time, material costs and reimbursement. In the two groups, a total of 52 individuals with 124 fragility fracture sites in sacral vertebrae I and II were surgically treated with similar numbers of screws inserted (p ≈ 0.679) requiring similar 3D- (p ≈ 0.546) and 2D-fluoroscopy radiation doses (p ≈ 0.236). In procedures with ASP, average 2D-fluoroscopy time (46.6 s vs. 32.7 s, p ≈ 0.004), and mean surgical duration (119 min vs. 96 min, p ≈ 0.011) were significantly longer. Mean implant costs (EUR 668.68 vs. EUR 204.34, p < 0.001), and reimbursement (EUR 8416.01 vs. EUR 6584.49, p ≈ 0.006) were significantly higher. Although comparison of costs and reimbursements indicated a positive financial balance, profitability was not confirmed, because financial expense for extended operative time prevented an economic advantage of procedures with ASP in this investigation. A formula was developed based on presented study data to allow similar economical decisions in other health care systems or institutions with differing resource costs

Planning for Self-Employment at the Beginning of a Market Economy : Evidence from Individual Data of East German Workers

SIGLEAvailable from Bibliothek des Instituts fuer Weltwirtschaft, ZBW, Duesternbrook Weg 120, D-24105 Kiel W 636 (92.01) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman

Handbook of Food Analysis Instruments

This monograph published by Taylor&Francis Publishing House contains versatile instrumentation that is applied in food analysis. More than 40 authors, experts from different fields, took part in writing comprehensive chapters related to various aspects of microscopic, chromatographic, UV VIS, electrochemical, Fluorescence, Electrophoresis, AFM and IR techniques applied in food analysis. In the beginning of this book, authors provide comprehensive statistic relevant to analytical chemistry. Also, extraction and preparation methods in food analysis are extensively explained. The readers can get an insight in several free chapters of this Monograph (issued on line in 2016) available for free in 2021