Martin Hansis

Fluorine-18 fluorodeoxyglucose PET in infectious bone diseases: results of histologically confirmed cases.

Abstract.The aim of this study was to evaluate the clinical use of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in acute and chronic osteomyelitis and inflammatory spondylitis. The study population comprised 21 patients suspected of having acute or chronic osteomyelitis or inflammatory spondylitis. Fifteen of these patients subsequently underwent surgery. FDG-PET results were correlated with histopathological findings. The remaining six patients, who underwent conservative therapy, were excluded from any further evaluation due to the lack of histopathological data. The histopathological findings revealed osteomyelitis or inflammatory spondylitis in all 15 patients: seven patients had acute osteomyelitis and eight patients had chronic osteomyelitis or inflammatory spondylitis. FDG-PET yielded 15 true-positive results. The tracer uptake correlated with the histopathological findings in each case. Bone scintigraphy performed in 11 patients yielded ten true-positive results and one false-negative result. Follow-up carried out on two patients revealed normal or clearly reduced tracer uptake, which correlated with a normalisation of clinical data. In early postoperative follow-up it was impossible to differentiate between postsurgical reactive changes and further infection using FDG-PET. It is concluded that acute and chronic osteomyelitis of the peripheral as well as the central skeleton can be detected using FDG-PET. Osteomyelitis can be differentiated from soft tissue infection surrounding the bone. Unlike computed tomography and magnetic resonance imaging, FDG-PET is not affected by metal implants used for fixing fractures. FDG-PET demonstrated promising initial results with respect to treatment monitoring. Nevertheless, in the early postoperative phase FDG-PET seems to be of limited value owing to unspecific tracer uptake.

Striated muscle microvascular response to silver implants: A comparative in vivo study with titanium and stainless steel.

Local microvascular perfusion is the primary line of defense of tissue against microorganisms and plays a considerable role in reparative processes. The impairment of the microcirculation by a biomaterial may therefore have profound consequences. Silver is known to have excellent antimicrobial activity and, although regional and systemic toxic effects have been described, silver is regularly discussed as an implant material in bone surgery. Because little is known about the influence of silver implants on the adjacent host tissue microvasculature, we studied in vivo nutritive perfusion and leukocytic response, and compared these results with those of the conventionally used materials titanium and stainless steel. Using the hamster dorsal skinfold chamber preparation and intravital microscopy, the implantation of a commercially pure silver sample led to a distinct and persistent activation of leukocytes combined with a marked disruption of the microvascular endothelial integrity, massive leukocyte extravasation, and considerable venular dilation. Whereas animals with stainless-steel implants showed a moderate increase in these parameters with a tendency to recuperate, titanium implants caused only a transient increase of leukocyte-endothelial cell interaction within the first 120 min and no significant change in macromolecular leakage, leukocyte extravasation and venular diameter. After 3 days, five of six preparations with silver samples showed severe inflammation and massive edema. Thus, the use of silver as an implant material should be critically judged despite its bactericidal properties. The implant material titanium seems to be well tolerated by the local vascular system and currently represents the golden standard.

Susceptibility to local infection in biological internal fixation

Abstract Resistance to local infection after fracture fixation with plate osteosynthesis may be influenced by the implantation technique. It is known that the extent of the surgical approach to the bone can compromise the local defence capacity. We have investigated susceptibility to infection after a local bacterial challenge in rabbit tibiae using either the open surgical approach for ‘biological’ internal fixation of standard 2.0 dynamic compression plates or the method of minimally invasive plate osteosynthesis (MIPO), a percutaneous, tunnelling insertion technique preserving the integrity of the overlying soft tissue. After the wounds had been closed, various concentrations of Staphylococcus aureus were injected in the direct vicinity of the implants. The infection rate for the open surgical technique was 38.5% and that for the MIPO technique, 25%. This difference is not statistically significant (P > 0.05) suggesting that resistance to local infection associated with the MIPO method is at least equivalent to the open approach for plate osteosynthesis.

Influence of the design for fixation implants on local infection: experimental study of dynamic compression plates versus point contact fixators in rabbits.

OBJECTIVES Comparison of infection resistance after local bacterial challenge associated with two different designs for fixation implants: the conventional dynamic compression plate (DCP) and the point contact fixator (PC-Fix). DESIGN Randomized, prospective study in experimental animals. Grouped sequential experimental procedure. Observation time was twenty-eight days, with twenty animals per group. SETTING Following surgery, animals were kept without restrictions in individual hutches. ANIMALS Forty White New Zealand rabbits. Thirty-eight animals, nineteen per group, were included in the final evaluation. INTERVENTION Under sterile conditions, specially manufactured titanium DCP or PC-Fix of identical dimensions were fixed to rabbit tibiae. After wound closure, different concentrations of Staphylococcus aureus, between 2 x 10(4) and 2 x 10(8) colony-forming units (CFU), were inoculated percutaneously at the implant site. MAIN OUTCOME MEASUREMENTS Implants, underlying bone, and surrounding soft tissues were removed under sterile conditions and quantitatively evaluated for bacterial growth. Infection was defined as positive bacterial growth at the bone-implant interface. RESULTS The overall infection rate was 45 percent. The infection dose of 50 percent (ID50) was 7.08 x 10(5) CFU for the DCP group and 8.51 x 10(6) CFU for the PC-Fix group. The infection rate was 63 percent (twelve of nineteen animals) for the DCP group and 26 percent (five of nineteen animals) for the PC-Fix group. This difference was statistically significant (p = 0.022). CONCLUSIONS After local bacterial challenge, we found a statistically significant difference in the infection rates depending on the implant design. The higher infection resistance associated with the PC-Fix design seems to be related to the reduced contact area at the bone-implant interface.

Compression plating of tibial fractures following primary external fixation

During the time period from May 1990 to December 1992, a total of 75 tibia fractures were treated in the Department of Traumatology at the University of Bonn. Thirtyeight patients with 40 tibial fractures were managed according to a regimen including primary stabilization, usually using external fixation, soft tissue reconstruction and delayed open reduction and internal fixation using an AO compression plate. The majority of the patients had been involved in motor vehicle accidents, leading to multiple injuries in 24 instances. An open fracture was seen 18 times. The 20% complication rate is comparable to the reports following intramedullary stabilization. Only one infection, following a grade 2 open fracture, was seen after the definitive stabilization. Bony union was achieved after 15.7 weeks. In light of the complications associated with intramedullary nailing, such as fat or air embolism, heterotopic ossification and non- or malunions, use of the tibial plate does not offer just logistic advantages, but is a viable alternative for delayed stabilization of tibial fractures.No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.

Radiological signs of osteitis around extramedullary metal implants A radiographic-microbiological correlative analysis in rabbit tibiae after local inoculation of Staphylococcus aureus

Abstract Radiographic changes in the early stages of osteomyelitis may be subtle and, especially after plate osteosynthesis, frequently missed. A previously described experimental model of local bacterial infection was used in an attempt to determine the reliability of specific changes on conventional radiographs for the diagnosis of osteitis after metal-plate implantation and subsequent inoculation of Staphylococcus aureus in rabbit tibiae. Roentgenograms of the treated limbs were evaluated, and seven radiographic parameters, to which numerical scores were assigned, were determined for each bone. Our results substantiate the conclusion that a radiographically verified periosteal reaction is a constant and early skeletal feature of acute osteomyelitis and has the strongest association to the microbiological results (P < 0.05), emphasising its high predictive value. Plate implantation does not notably impede the diagnosis of osteomyelitis. An association between the amount of inoculated bacteria and the extent of radiographic changes could be found. The results of this present study closely resemble those described in man and suggest that this model may be useful for future experimental investigations in determining a score judging the severity of osseous involvement in local bacterial infection after plate osteosynthesis.

Risiko der posttraumatischen Osteitis bei Osteosynthesen

ZusammenfassungDie posttraumatische Osteitis nach Osteosynthesen ist nicht nur ein Risiko für die betroffenen Patienten, sondern auch für die Träger der Behandlungskosten und nicht zuletzt die behandelnden Ärzte. Nach der aktuellen pathophysiologischen Modellvorstellung sind der traumatische Gewebeschaden an Knochen und Weichteilen, das Ausmaß und die Art der bakteriellen Kontamination und die Anwesenheit von Implantaten als die führenden Risikofaktoren anzusehen. Das Risiko einer Infektion nach Frakturbehandlung durch Osteosynthese wird in der Literatur mit sehr unterschiedlich definierten und folglich mit erheblich variierenden Infektraten quantifiziert. Zeitnahe prospektive multizentrische Untersuchungen mit genügend hohen Fallzahlen gehen von Werten bis 5% bei geschlossenen Frakturen aus, die bei offenen Frakturen in Abhängigkeit vom Begleittrauma auf ein Vielfaches ansteigen können. Es ist zu erwarten, dass das Osteitisrisiko nach Osteosynthese letztlich nur durch die konsequente Durchführung risikoadaptierter, mehrzeitiger und multimodaler chirurgischer Therapiestrategien weiter gesenkt werden kann.AbstractPosttraumatic osteitis following fracture treatment with fixation devices can be regarded as a risk not only for the individual patient but also for the insurance company concerned and finally for the treating surgeon. According to the current pathophysiological model, the traumatic damage to the bone and soft tissues, the extent and type of bacterial contamination and the presence of foreign body implants have to be regarded as the leading risk factors. In the literature the risk of infection following fracture treatment with fixation devices is quantified with the aid of very variously defined infection rates, which therefore vary substantially. Recent prospective multicenter investigations with sufficiently large numbers of cases point to infection rates of up to 5% following closed fractures, while the rates for compound fractures can be several times as high, depending essentially on the accompanying trauma. It is to be expected that the risk of osteitis following osteosynthesis will ultimately be further reduced only through strict application of risk-adapted, sequential and differentiated therapeutic surgical stategies.

Erläuterungen zu den Empfehlungen der Kommission für Krankenhaushygiene und Infektionsprävention zur Surveillance von postoperativen Wundinfektionen in Einrichtungen für das ambulante Operieren

ZusammenfassungSeit Anfang 2001 fordert das Infektionsschutzgesetz nicht nur die Surveillance von nosokomialen Infektionen in mindestens einem Risikobereich des Krankenhauses wie Intensivstation oder operativen Abteilungen. Es fordert ebenfalls die Surveillance von postoperativen Wundinfektionen in Einrichtungen für das ambulante Operieren. Allerdings reicht es nicht aus, die Fälle von postoperativen Wundinfektionen zu registrieren und Wundinfektionsraten zu berechnen, es bedeutet auch, dass die Daten sorgfältig interpretiert werden, um daraus geeignete Schlussfolgerungen für die Prävention in der Zukunft zu ziehen. Die Orientierung an existierenden Referenzdaten ist notwendig, aber der Vergleich mit Infektionsraten aus Krankenhäusern ist wegen der unterschiedlichen Operationsarten, der divergierenden Patientenzusammensetzung, der OP-Bedingungen und der anderen postoperativen Nachverfolgung der Patienten ungeeignet. Weil der NNIS-Risiko-Index für die Anwendung in Einrichtungen für das ambulante Operieren ungeeignet ist, wird die Berechnung von rohen Wundinfektionsraten empfohlen. Zur Orientierung an Referenzdaten können zunächst für die sowohl im Krankenhaus als auch in Einrichtungen für das ambulante Operieren durchgeführten OP-Arten zunächst die Wundinfektionsraten der Risikokategorie 0 aus dem Krankenhaus-Infektions-Surveillance-System (KISS) bestimmt werden; künftig könnte dann die Orientierung an den Daten einer noch aufzubauenden Referenzdatenbank für postoperative Wundinfektionen in Einrichtungen für das ambulante Operieren erfolgen. Der Artikel beschreibt die Hintergründe für die Festlegungen der Empfehlungen zur Surveillance von postoperativen Wundinfektionen in Einrichtungen für das ambulante Operieren.AbstractSince the beginning of 2001, the German Protection Infection Act requires the ongoing surveillance of nosocomial infections in at least one hospital department with a high risk oft these infections, such as intensive care units or surgical departments. In addition, it also requires the surveillance of surgical site infections in surgical outpatient settings. However, surveillance consists not only in registering cases of nosocomial infection and calculating infection rates, it also means interpreting infection data carefully in order to be able to draw appropriate conclusions for reducing surgical site infections in the future. A comparison with already available reference data is necessary, although comparison with data from hospitals may turn out to be misleading due to the different types of operations, patient mixture, surgical conditions and the subsequent follow-up conditions. As the NNIS risk index is of no practical use in outpatient settings, calculation of the crude SSI rates is recommended, comparing them with hospital surveillance data of patients in risk group 0 of KISS (Krankenhaus-Infektions-Surveillance-System), at least for those operations which are performed not only in hospitals but also in an outpatient situation. In the long run, the establishment of a surveillance system for surgical site infections in outpatient settings will be necessary in order to generate reference data for outpatient surgery patients. This article describes the background of the recommendations of the commission for hospital hygiene at the Robert Koch-Institut for the surveillance of surgical site infections in an outpatient setting.

Zukünftige Präventions- und Kontrollstrategien in der Krankenhaushygiene

definiert ist [1], wird fur den Begriff Krankenhaushygiene keine Definition gegeben. Unter Krankenhausinfektion (nosokomiale Infektion) wird jede durch Mikroorganismen hervorgerufene Infektion verstanden, die im kausalen Zusammenhang mit einem Krankenhausaufenthalt steht, unabhangig davon, ob Krankheitssymptome bestehen oder nicht. Eine epidemische Krankenhausinfektion (Ausbruch) liegt dann vor, wenn Infektionen mit einheitlichem Erregertyp, mit zeitlichem, ortlichem und kausalem Zusammenhang zu einem Krankenhausaufenthalt nicht nur vereinzelt auftreten. Im Entwurf fur ein Infektionsschutzgesetz (Stand: Marz 1999) sind beide Termini im Sinne einer Legaldefinition jetzt so beschrieben:

Manubriosternale Luxation durch indirektes Stauchungstrauma : Fallbericht und Literaturübersicht

ZusammenfassungEine manubriosternale Luxation insbesondere durch ein indirektes Stauchungstrauma stellt eine ausgesprochene Rarität dar. Es werden 2 Typen der manubriosternalen Luxation voneinander unterschieden. Bei einer Typ-I-Luxation luxiert das Corpus sterni nach dorsal, bei einer Typ-II-Luxation liegt das Corpus sterni in Relation zum Manubrium sterni ventral. Zu einer manubriosternalen Luxation kann es durch ein direktes oder indirektes Trauma kommen. Bei direkten Traumata handelt es sich meist um Anpralltraumata im Rahmen von Verkehrsunfällen. Es kann sowohl eine Typ-I-Luxation als auch eine Typ-II-Luxation resultieren. Ein indirektes Trauma führt aufgrund eines Flexion-Kompression-Mechanismus im Bereich der Wirbelsäule zu einer Typ-II-Luxation.Prädisponierend für eine manubriosternale Luxation durch ein indirektes Stauchungstrauma ist eine rheumatische Arthritis bzw. eine ausgeprägte Kyphose. Die konservative Therapie nach Reposition durch redressierende Tape- bzw. Pflasterverbände, symptomatische Schmerztherapie, Eisanwendungen und mehrwöchiges Sportverbot geht insbesondere bei ungenügender Patientencompliance mit einer nicht unerheblichen Rate an Subluxationen bzw. Reluxationen einher. Dies kann zu chronischen Schmerzen, periartikulären Verkalkungen mit Ankylosierung und fortschreitender Deformität führen. Ein optimales, standardisiertes Operationsverfahren konnte aufgrund der geringen Fallzahlen bisher nicht etabliert werden. Wir konnten ein sehr gutes postoperatives Langzeitergebnis nach Verwendung von zwei 8-Loch-Drittelrohrplatten zur Fixation des Repositionsergebnisses nach manubriosternaler Luxation durch ein indirektes Stauchungstrauma erzielen.AbstractManubriosternal dislocation caused by indirect flexion-compression trauma is an extremely rare condition. Two forms of manubriosternal luxation are distinguished: in type I the sternum is dislocated posterior and in type II anterior to the manubrium. Direct or indirect trauma may cause manubriosternal dislocation. Mode of injury in direct trauma is mostly a head-on collition in a motor accident resulting either in type I or type II luxation. The unusual origin of manubriosternal dislocation by indirect trauma is put down to flexion-compression injuries of the thoracic spine and results in a type II dislocation. Predisposition to manubriosternal dislocation by indirect trauma consists in rheumatoid arthritis or extreme forms of kyphosis. Outcome of many patients treated conservatively after initial reposition with adhesive tape, symptomatic pain therapy, cryotherapy and prohibition of any physical training over several weeks is subluxation or complete luxation of the manubriosternal joint. This condition may lead to chronic pain, periarticular calcification with ankylosis and progredient deformation. Lacking a controlled study for treatment of manubriosternal dislocation a standard therapeutic regime could not be established yet. In the literature only a few case-reports of patients undergoing operative therapy are published. We report a type II dislocation of the manubriosternal joint caused by indirect flexion-compression trauma. We achieved a very good long-term result using a 8-hole 1/3 tubular plate for fixation of the manubriosternal joint after reposition.