Microbial load in instruments used in surgeries classified as clean

Introduction / objectives The number of orthopedic surgery, especially surgery of total hip and knee, have been more frequent due to technological advances. This study aims to determine the microbial load in the instruments used in clean surgeries, quantifying and identifying the genus and species of microbial growth.Methods Orthopedic surgical instruments were immersed, after use, in sterile water, sonicated in ultrasonic washer and consecutively shaken. Then, the lavage was filtered through a 0.45micron membrane, the result was incubated in aerobic medium, anaerobic medium and medium for fungi and yeasts. Results In clean surgeries, results showed that 47% of used instruments had microbiological growth in the range of 1 to 100 CFU/instrument. The most prevalent organism was Staphylococcus coagulase negative (28%), followed by Bacillus subtilis (11%).This study refuted the hypothesis that clean surgeries happen in micro-organismsfree surgery field. Conclusion The microbiological findings reinforce the importance of antibiotic prophylaxis, practice already well established for this category of surgical procedure.

CRRT nel paziente ad alto rischio emorragico: ottimizzazione di un protocollo di anticoagulazione regionale con citrato

L’anticoagulazione regionale con citrato (RCA) è una valida opzione in pazienti ad alto rischio emorragico. Lo scopo del nostro studio è stato di valutare, in pazienti critici sottoposti a CRRT per insufficienza renale acuta post-cardiochirurgica, efficacia e sicurezza di un protocollo di RCA in CVVH con l’impiego di una soluzione di citrato a bassa concentrazione (12mmol/L). Metodi: L’RCA-CVVH è stata adottata come alternativa all’eparina o alla CRRT senza anticoagulante (no-AC). Criteri per lo switch verso l’RCA: coagulazione dei circuiti entro 24h o complicanze legate all’eparina. Per facilitare l’impostazione dei parametri CVVH, abbiamo sviluppato un modello matematico per stimare il carico metabolico di citrato e la perdita di calcio. Risultati: In 36 mesi, sono stati sottoposti a RCA-CVVH 30 pazienti. La durata dei circuiti con RCA (50.5 ± 35.8 h, mediana 41, 146 circuiti) è risultata significativamente maggiore (p<0.0001) rispetto all’eparina (29.2±22.7 h, mediana 22, 69 circuiti) o alla no-AC CRRT (24.7±20.6 h, mediana 20, 74 circuiti). Il numero di circuiti funzionanti a 24, 48, 72 h è risultato maggiore durante RCA (p<0.0001). I target di Ca++ sistemico e del circuito sono stati facilmente mantenuti (1.18±0.13 e 0.37±0.09 mmol/L). Durante l’RCA-CVVH nessun paziente ha avuto complicanze emorragiche e il fabbisogno trasfusionale si è ridotto rispetto alle altre modalità (0.29 vs 0.69 unità/die, p<0.05). Le piastrine (p=0.012) e l’AT-III (p=0.004) sono aumentate durante RCA riducendo la necessità di supplementazione. L’RCA è stata interrotta per accumulo di citrato in un solo paziente (calcemia totale/s-Ca++ >2.5). Conclusioni: L’RCA ha consentito di prolungare la durata dei circuiti riducendo il fabbisogno trasfusionale e la necessità di supplementazione di AT-III e piastrine. L’utilizzo di un modello matematico ha facilitato l’impostazione dei parametri CVVH. L’RCA appare meritevole di maggiore considerazione come metodica di anticoagulazione di prima scelta in pazienti ad alto rischio emorragico sottoposti a CRRT.

Spectroscopic study of Bioceramics for Endodontic and Orthopaedics

This thesis was aimed at investigating the physical-chemical properties and the behaviour in physiological environment of two classes of bioceramics: calcium silicate-based dental cements and alumina-based femoral heads for hip joint prostheses. The material characterization was performed using spectroscopic techniques such as that allow to obtain information on the molecular structure of the species and phases present in the analyzed samples. Raman, infrared and fluorescence spectroscopy was principally used. Calcium silicate cements, such as MTA (Mineral Trioxide Aggregate), are hydraulic materials that can set in presence of water: this characteristic makes them suitable for oral surgery and in particular as root-end filling materials. With the aim to improve the properties of commercial MTA cements, several MTA-based experimental formulations have been tested with regard to bioactivity (i.e. apatite forming ability) upon ageing in simulated body fluids. The formation of a bone-like apatite layer may support the integration in bone tissue and represents an essential requirement for osteoconduction and osteoinduction. The spectroscopic studies demonstrated that the experimental materials under study had a good bioactivity and were able to remineralize demineralized dentin. . Bioceramics thanks to their excellent mechanical properties and chemical resistance, are widely used as alternative to polymer (UHMWPE) and metal alloys (Cr-Co) for hip-joint prostesis. In order to investigate the in vivo wear mechanisms of three different generations of commercial bioceramics femoral heads (Biolox®, Biolox® forte, and Biolox® delta), fluorescence and Raman spectroscopy were used to investigate the surface properties and residual stresses of retrieved implants. Spectroscopic results suggested different wear mechanisms in the three sets of retrievals. Since Biolox® delta is a relatively recent material, the Raman results on its retrievals has been reported for the first time allowing to validate the in vitro ageing protocols proposed in the literature to simulate the effects of the in vivo wear.

Recupero della funzione renale in pazienti con acute kidney injury (AKI) sottoposti a terapia sostitutiva renale

L’insufficienza renale acuta(AKI) grave che richiede terapia sostitutiva, è una complicanza frequente nelle unità di terapia intensiva(UTI) e rappresenta un fattore di rischio indipendente di mortalità. Scopo dello studio é stato valutare prospetticamente, in pazienti “critici” sottoposti a terapie sostitutive renali continue(CRRT) per IRA post cardiochirurgia, la prevalenza ed il significato prognostico del recupero della funzione renale(RFR). Pazienti e Metodi:Pazienti(pz) con AKI dopo intervento di cardiochirurgia elettivo o in emergenza con disfunzione di due o più organi trattati con CRRT. Risultati:Dal 1996 al 2011, 266 pz (M 195,F 71, età 65.5±11.3aa) sono stati trattati con CRRT. Tipo di intervento: CABG(27.6%), dissecazione aortica(33%), sostituzione valvolare(21.1%), CABG+sostituzione valvolare(12.6%), altro(5.7%). Parametri all’inizio del trattamento: BUN 86.1±39.4, creatininemia(Cr) 3.96±1.86mg/dL, PAM 72.4±13.6mmHg, APACHE II score 30.7±6.1, SOFAscore 13.7±3. RIFLE: Risk (11%), Injury (31.4%), Failure (57.6%). AKI oligurica (72.2%), ventilazione meccanica (93.2%), inotropi (84.5%). La sopravvivenza a 30 gg ed alla dimissione è stata del 54.2% e del 37.1%. La sopravvivenza per stratificazione APACHE II: <24=85.1 e 66%, 25-29=63.5 e 48.1%, 30-34=51.8 e 31.8%, >34=31.6 e 17.7%. RFR ha consentito l’interruzione della CRRT nel 87.8% (86/98) dei survivors (Cr 1.4±0.6mg/dL) e nel 14.5% (24/166) dei nonsurvivors (Cr 2.2±0.9mg/dL) con un recupero totale del 41.4%. RFR è stato osservato nel 59.5% (44/74) dei pz non oligurici e nel 34.4% dei pz oligurici (66/192). La distribuzione dei pz sulla base dei tempi di RFR è stata:<8=38.2%, 8-14=20.9%, 15-21=11.8%, 22-28=10.9%, >28=18.2%. All’analisi multivariata, l’oliguria, l’età e il CV-SOFA a 7gg dall’inizio della CRRT si sono dimostrati fattori prognostici sfavorevoli su RFR(>21gg). RFR si associa ad una sopravvivenza elevata(78.2%). Conclusioni:RFR significativamente piu frequente nei pz non oligurici si associa ad una sopravvivenza alla dimissione piu elevata. La distribuzione dei pz in rapporto ad APACHE II e SOFAscore dimostra che la sopravvivenza e RFR sono strettamente legati alla gravità della patologia.

A New Test Rig for In-Vitro Evaluation of the Knee Joint Behaviour

The evaluation of the knee joint behavior is fundamental in many applications, such as joint modeling, prosthesis and orthosis design. In-vitro tests are important in order to analyse knee behavior when simulating various loading conditions and studying physiology of the joint. A new test rig for in-vitro evaluation of the knee joint behavior is presented in this paper. It represents the evolution of a previously proposed rig, designed to overcome its principal limitations and to improve its performances. The design procedure and the adopted solution in order to satisfy the specifications are presented here. Thanks to its 6-6 Gough-Stewart parallel manipulator loading system, the rig replicates general loading conditions, like daily actions or clinical tests, on the specimen in a wide range of flexion angles. The restraining actions of knee muscles can be simulated when active actions are simulated. The joint motion in response to the applied loads, guided by passive articular structures and muscles, is permitted by the characteristics of the loading system which is force controlled. The new test rig guarantees visibility so that motion can be measured by an optoelectronic system. Furthermore, the control system of the new test rig allows the estimation of the contribution of the principal leg muscles in guaranteeing the equilibrium of the joint by the system for muscle simulation. Accuracy in positioning is guaranteed by the designed tibia and femur fixation systems,which allow unmounting and remounting the specimen in the same pose. The test rig presented in this paper permits the analysis of the behavior of the knee joint and comparative analysis on the same specimen before and after surgery, in a way to assess the goodness of prostheses or surgical treatments.

Perioperative metabolic changes in patients undergoing cardiac surgery

Perioperative metabolic changes in cardiac surgical patients are not only induced by tissue injury and extracorporeal circulation per se: the systemic inflammatory response to surgical trauma and extracorporeal circulation, perioperative hypothermia, cardiovascular and neuroendocrine responses, and drugs and blood products used to maintain cardiovascular function and anesthesia contribute to varying degrees. The pathophysiologic changes include increased oxygen consumption and energy expenditure; increased secretion of adrenocorticotrophic hormone, cortisol, epinephrine, norepinephrine, insulin, and growth hormone; and decreased total tri-iodothyronine levels. Easily measurable metabolic consequences of these changes include hyperglycemia, hyperlactatemia, increased aspartate, glutamate and free fatty acid concentrations, hypokalemia, increased production of inflammatory cytokines, and increased consumption of complement and adhesion molecules. Nutritional risk before elective cardiac surgery-defined as preoperative unintended pathologic weight loss/low amount of food intake in the preceding week or low body mass index-is related to adverse postoperative outcome. Improvements in surgical techniques, anesthesia, and perioperative management have been designed to minimize the stressful stimulus to catabolism, thereby slowing the wasting process to the point where much less nutrition is required to meet metabolic requirements. Early nutrition in cardiac surgery is safe and well tolerated.

Risk factors for early dislocation after total hip arthroplasty: a matched case-control study

To evaluate risk factors for early dislocation after primary total hip arthroplasty (THA).

Material properties of common suture materials in orthopaedic surgery

Suture materials in orthopaedic surgery are used for closure of wounds, repair of fascia, muscles, tendons, ligaments, joint capsules, and cerclage or tension band of certain fractures. The purpose of this study was to compare the biomechanical properties of eleven commonly used sutures in orthopaedic surgery. Three types of braided non-absorbable and one type of braided absorbable suture material with different calibers (n=77) underwent biomechanical testing for maximum load to failure, strain, and stiffness. All samples were tied by one surgeon with a single SMC (Seoul Medical Center) knot and three square knots. The maximum load to failure and strain were highest for #5 FiberWire and lowest for #0 Ethibond Excel (p<0.001). The stiffness was highest for #5 FiberWire and lowest for #2-0 Vicryl (p<0.001). In all samples, the failure of the suture material occurred at the knot There was no slippage of the knot in any of the samples tested. This data will assist the orthopaedic surgeon in selection and application of appropriate suture materials and calibers to specific tasks.

Automated detection of fiducial screws from CT/DVT volume data for image-guided ENT surgery

This paper presents an automated solution for precise detection of fiducial screws from three-dimensional (3D) Computerized Tomography (CT)/Digital Volume Tomography (DVT) data for image-guided ENT surgery. Unlike previously published solutions, we regard the detection of the fiducial screws from the CT/DVT volume data as a pose estimation problem. We thus developed a model-based solution. Starting from a user-supplied initialization, our solution detects the fiducial screws by iteratively matching a computer aided design (CAD) model of the fiducial screw to features extracted from the CT/DVT data. We validated our solution on one conventional CT dataset and on five DVT volume datasets, resulting in a total detection of 24 fiducial screws. Our experimental results indicate that the proposed solution achieves much higher reproducibility and precision than the manual detection. Further comparison shows that the proposed solution produces better results on the DVT dataset than on the conventional CT dataset.

All cause and disease specific mortality in patients with knee or hip osteoarthritis: population based cohort study

Objective To examine all cause and disease specific mortality in patients with osteoarthritis of the knee or hip. Design Population based cohort study. Setting General practices in the southwest of England. Participants 1163 patients aged 35 years or over with symptoms and radiological confirmation of osteoarthritis of the knee or hip. Main outcome measures Age and sex standardised mortality ratios and multivariable hazard ratios of death after a median of 14 years’ follow-up. Results Patients with osteoarthritis had excess all cause mortality compared with the general population (standardised mortality ratio 1.55, 95% confidence interval 1.41 to 1.70). Excess mortality was observed for all disease specific causes of death but was particularly pronounced for cardiovascular (standardised mortality ratio 1.71, 1.49 to 1.98) and dementia associated mortality (1.99, 1.22 to 3.25). Mortality increased with increasing age (P for trend <0.001), male sex (adjusted hazard ratio 1.59, 1.30 to 1.96), self reported history of diabetes (1.95, 1.31 to 2.90), cancer (2.28, 1.50 to 3.47), cardiovascular disease (1.38, 1.12 to 1.71), and walking disability (1.48, 1.17 to 1.86). However, little evidence existed for increased mortality associated with previous joint replacement, obesity, depression, chronic inflammatory disease, eye disease, or presence of pain at baseline. The more severe the walking disability, the higher was the risk of death (P for trend <0.001). Conclusion Patients with osteoarthritis are at higher risk of death compared with the general population. History of diabetes, cancer, or cardiovascular disease and the presence of walking disability are major risk factors. Management of patients with osteoarthritis and walking disability should focus on effective treatment of cardiovascular risk factors and comorbidities, as well as on increasing physical activity.

Hypotension during fluid-restricted abdominal surgery: effects of norepinephrine treatment on regional and microcirculatory blood flow in the intestinal tract

Vasopressors, such as norepinephrine, are frequently used to treat perioperative hypotension. Increasing perfusion pressure with norepinephrine may increase blood flow in regions at risk. However, the resulting vasoconstriction could deteriorate microcirculatory blood flow in the intestinal tract and kidneys. This animal study was designed to investigate the effects of treating perioperative hypotension with norepinephrine during laparotomy with low fluid volume replacement.