PET Imaging of Osteomyelitis. Feasibility of 18F-FDG, 68Ga-Chloride and 68Ga-DOTAVAP-P1 Tracers in Staphylococcal Bone Infections

Due to technical restrictions of the database system the title of the thesis does not show corretly on this page. Numbers in the title are in superscript. Please see the PDF-file for correct title. ---- Osteomyelitis is a progressive inflammatory disease of bone and bone marrow that results in bone destruction due to an infective microorganism, most frequently Staphylococcus aureus. Orthopaedic concern relates to the need for reconstructive and trauma-related surgical procedures in the fast grow¬ing population of fragile, aged patients, who have an increased susceptibility to surgical site infections. Depending on the type of osteomyelitis, infection may be acute or a slowly progressing, low-grade infection. Peri-implant infections lead to implant loosening. The emerging antibiotic resistance of com¬mon pathogens further complicates the situation. With current imaging methods, significant limitations exist in the diagnosing of osteomyelitis and implant-related infections. Positron emission tomography (PET) with a glucose analogue, 18F-fluoro¬deoxyglucose (18F-FDG), seems to facilitate a more accurate diagnosis of chronic osteomyelitis. The method is based on the increased glucose consumption of activated inflammatory cells. Unfortunately, 18F-FDG accumulates also in sterile inflammation regions and causes false-positive findings, for exam¬ple, due to post-operative healing processes. Therefore, there is a clinical need for new, more infection-specific tracers. In addition, it is still unknown why 18F-FDG PET imaging is less accurate in the detec¬tion of periprosthetic joint infections, most frequently due to Staphylococcus epidermidis. This doctoral thesis focused on testing novel PET tracers (68Ga-chloride and 68Ga-DOTAVAP-P1) for early detections of bone infections and evaluated the role of pathogen-related factors in the appli¬cations of 18F-FDG PET in the diagnostics of bone infections. For preclinical models of S. epidermidis and S. aureus bone/implant infections, the significance of the causative pathogen was studied with respect to 18F-FDG uptake. In a retrospective analysis of patients with confirmed bone infections, the significance of the presence or absence of positive bacterial cultures on 18F-FDG uptake was evalu¬ated. 18F-FDG and 68Ga-chloride resulted in a similar uptake in S. aureus osteomyelitic bones. However, 68Ga-chloride did not show uptake in healing bones, and therefore it may be a more-specific tracer in the early post-operative or post-traumatic phase. 68Ga-DOTAVAP-P1, a novel synthetic peptide bind¬ing to vascular adhesion protein 1 (VAP-1), was able to detect the phase of inflammation in healing bones, but the uptake of the tracer was elevated also in osteomyelitis. Low-grade peri-implant infec¬tions due to S. epidermidis were characterized by a low uptake of 18F-FDG, which reflects the virulence of the causative pathogen and the degree of leukocyte infiltration. In the clinical study, no relationship was found between the level of 18F-FDG uptake and the presence of positive or negative bacterial cul¬tures. Thus 18F-FDG PET may help to confirm metabolically active infection process in patients with culture-negative, histologically confirmed, low-grade osteomyelitis.Siirretty Doriast

Luun infektiot

Osteomyeliitti syntyy luun bakteeritartunnasta. Lapsilla bakteeri pääsee luuhun yleisimmin verivälitteisesti, iholta tai hengitysteitse. Aikuisväestössä diabeteksen tai ahtauttavan valtimotaudin yhteydessä krooniset alaraajahaavat mahdollistavat suoran luutartunnan. Osteomyeliittiä esiintyy myös avomurtumien tai elektiivisten tuki- ja liikuntaelinleikkausten jälkeen. Lämpöily ja raaja- tai selkäkipu ovat tyypillisiä akuutin purulentin osteomyeliitin oireita, mutta kroonisissa tapauksissa oireet ovat usein lievemmät. Magneettikuvaus on osteomyeliitin paras kuvantamismenetelmä. Krooniset tapaukset voidaan havaita jo natiiviröntgenkuvastakin. Akuuteissa tapauksissa suonensisäinen mikrobilääkehoito aloitetaan sairaalassa. Lasten komplisoitumattoman verivälitteisen osteomyeliitin mikrobilääkehoito kestää kolme viikkoa, aikuisten hoidossa suositaan usein pidempiä mikrobilääkekuureja. Osteomyeliitin ennuste riippuu potilaan perussairaudesta ja aiheuttavasta tekijästä.</p

Arvoperusteiset korvausmallit terveydenhuollossa - esimerkkinä polven tekonivelleikkaus

Polven tekonivelleikkausten kysynnän kasvun on ennakoitu kuormittavan terveydenhuoltojärjestelmää. Keskittyminen arvoon eli terveydenhuollon palvelujen tuottaman hyödyn ja näiden tuotantokustannusten suhteeseen on tärkeää. Arvoperusteisilla korvausmalleilla pyritään johdonmukaistamaan maksajien ja palveluntarjoajien toimintaa, kannustamaan hoidon koordinointiin, palkitsemaan tiettyjen kriteerien saavuttamista ja hillitsemään heikosti arvoa tuottavien hoitojen käyttöä. Episodikohtaisilla bundled payment -korvausmalleilla sairauden hoitoon kuuluvista palveluista maksetaan niputettu yhteismaksu. Näillä malleilla voidaan korvata suoriteperusteinen korvausmalli, jolla on todettu olevan yhteys ­terveydenhuollon kustannusten kasvuun.</p

Are patient-related pre-operative factors influencing return to work after total knee arthroplasty

Background: Osteoarthritis is one of the leading causes of disability in working-age patients. The total number of working-age patients undergoing total-knee arthroplasty (TKA) is continuously increasing. The purpose of this study was to identify predictive factors related to general health, health risk behaviors and socioeconomic status influencing the rate of return to work after a TKA. Methods: Overall there were 151,901 patients included in the Finnish Public Sector (FPS) study. The response rate varied between 65 and 73% during the study period. We used Cox proportional hazard models to examine patient-related predictive factors that may influence the rate of return to work after TKA in a cohort of patients (n = 452; n = 362 female; mean age 56.4 years). Predictive factors were measured on average 3.6 years before the operation. Results: Of the patients, 87% returned to work within one year after TKA at a mean of 116 calendar days. In multivariate analysis, patients at sick-leave 30 days of sick-leave. Compared with patients in manual work, those in higher or lower level non-manual work showed a 2.6-fold (1.95-3.52) and 1.5-fold (1.15-1.92) increased probability of returning to work. Age, sex, health risk behaviors, obesity, physical comorbidities, common mental disorders, and other studied health-related factors were not associated with the rate of return to work. Conclusions: Non-manual job, good self-rated general health and preoperative sick leavePeer reviewe

Return to work after primary total hip arthroplasty : a nationwide cohort study

Background and purpose While the number of working-age patients undergoing total hip arthroplasty (THA) is increasing, the effect of the surgery on patients' return to work (RTW) is not thoroughly studied. We aimed to identify risk factors of RTW after THA among factors related to demographic variables, general health, health risk behaviors, and socioeconomic status.Patients and methods We studied 408 employees from the Finnish Public Sector (FPS) cohort (mean age 54 years, 73% women) who underwent THA. Information on demographic and socioeconomic variables, preceding health, and health-risk behaviors was derived from linkage to national health registers and FPS surveys before the operation. The likelihood of return to work was examined using Cox proportional hazard modeling.Results 94% of the patients returned to work after THA on average after 3 months (10 days to 1 year) of sickness absence. The observed risk factors of successful return to work were: having <30 sick leave days during the last year (HR 1.8; 95% CI 1.4-2.3); higher occupational position (HR 2.2; CI 1.6-2.9); and BMI <30 (HR 1.4; CI 1.1-1.7). Age, sex, preceding health status, and health-risk behaviors were not correlated with RTW after the surgery.Interpretation Most employees return to work after total hip arthroplasty. Obese manual workers with prolonged sick leave before the total hip replacement were at increased risk of not returning to work after the surgery.Peer reviewe

Kirurginen savu toimenpiteissä - henkilöstön riskit ja suojaus

• Monia sähkökirurgisia instrumentteja käytettäessä syntyy kirurgista savua. • Henkilöstö voi altistua kumulatiivisesti savun haitallisille komponenteille. • Tavallinen kirurginen hengityssuojain antaa yli 90-prosenttisen suojan. Lisäksi tulisi käyttää asianmukaisella suodattimella varustettua paikallista savunpoistolaitteistoa. • Savulle altistumisen ei ole osoitettu lisäävän sairastavuutta tai syöpäriskiä.</p

Kirurginen savu toimenpiteissä - henkilöstön riskit ja suojaus

Vertaisarvioitu• Monia sähkökirurgisia instrumentteja käytettäessä syntyy kirurgista savua. • Henkilöstö voi altistua kumulatiivisesti savun haitallisille komponenteille. • Tavallinen kirurginen hengityssuojain antaa yli 90-prosenttisen suojan. Lisäksi tulisi käyttää asianmukaisella suodattimella varustettua paikallista savunpoistolaitteistoa. • Savulle altistumisen ei ole osoitettu lisäävän sairastavuutta tai syöpäriskiä.Peer reviewe

Return to work after lumbar disc herniation surgery : an occupational cohort study

Background and purpose - Lumbar disc herniation is a common surgically treated condition in the working-age population. We assessed health-related risk factors for return to work (RTW) after excision of lumbar disc herniation. Previous studies on the subject have had partly contradictory findings. Patients and methods - RTW of 389 (n = 111 male, n = 278 female; mean age 46 years, SD 8.9) employees who underwent excision of lumbar disc herniation was assessed based on the Finnish Public Sector Study (FPS). Baseline information on occupation, preceding health, and health-risk behaviors was derived from linkage to national health registers and FPS surveys before the operation. The likelihood of RTW was analyzed using Cox proportional hazard univariable and multivariable modelling. Results - 95% of the patients had returned to work at 12 months after surgery, after on average 78 days of sickness absence. Faster RTW in the univariable Cox model was associated with a small number of sick leave days (< 30 days) before operation (HR 1.3, 95% CI 1.1-1.6); high occupational position (HR 1.6, CI 1.2-2.1); and age under 40 years (HR 1.5, CI 1.1-1.9). RTW was not associated with sex or the health-related risk factors obesity, physical inactivity, smoking, heavy alcohol consumption, poor self-rated health, psychological distress, comorbid conditions, or purchases of pain or antidepressant medications in either the univariable or multivariable model. Interpretation - Almost all employees returned to work after excision of lumbar disc herniation. Older age, manual job, and prolonged sick leave before the excision of lumbar disc herniation were risk factors for delayed return to work after the surgery.Peer reviewe

Return to work following anterior cruciate ligament reconstruction

BACKGROUND AND PURPOSE: Amongst people of working age, the return to work (RTW) after anterior cruciate ligament (ACL) reconstruction is an important marker of success of surgery. We determined when patients are able to return to work after ACL reconstruction and identified factors that are associated with the timing of RTW. PATIENTS AND METHODS: We used logistic regression analyses to examine patient-related factors that may be associated with the length of RTW (above vs. below the median 59 days) after arthroscopic ACLR in a large cohort of patients working in the public sector in Finland (n = 803; n = 334 male, n = 469 female; mean age 41 years [SD 8.6]). RESULTS: The mean length of RTW was 65 days (SD 41). Higher odds ratios (OR) were observed for age groups 40-49 and ≥ 50 years compared with ≤ 30 years old (OR 2.0, 95% confidence interval 1.3-3.1 and 2.0, 1.2-3.4, respectively); for lower level non-manual and manual work compared with higher level non-manual work (3.0, 2.0-4.3 and 4.9, 3.4-7.0, respectively); and for those who had been on sick leave > 30 days in the preceding year (2.0, 1.4-2.9). Sex, comorbid conditions, preceding antidepressant treatment and concomitant procedures were not associated with the length of RTW. INTERPRETATION: Factors associated with prolonged sick leave beyond the median time of 59 days are higher age, lower occupational status, and preoperative sick leaves

Return to work following anterior cruciate ligament reconstruction

Background and purpose - Amongst people of working age, the return to work (RTW) after anterior cruciate ligament (ACL) reconstruction is an important marker of success of surgery. We determined when patients are able to return to work after ACL reconstruction and identified factors that are associated with the timing of RTW. Patients and methods - We used logistic regression analyses to examine patient-related factors that may be associated with the length of RTW (above vs. below the median 59 days) after arthroscopic ACLR in a large cohort of patients working in the public sector in Finland (n = 803; n = 334 male, n = 469 female; mean age 41 years [SD 8.6]). Results - The mean length of RTW was 65 days (SD 41). Higher odds ratios (OR) were observed for age groups 40-49 and >= 50 years compared with 30 days in the preceding year (2.0, 1.4-2.9). Sex, comorbid conditions, preceding antidepressant treatment and concomitant procedures were not associated with the length of RTW. Interpretation - Factors associated with prolonged sick leave beyond the median time of 59 days are higher age, lower occupational status, and preoperative sick leaves.Peer reviewe