Mycoplasma hominis deep wound infection after neuromuscular scoliosis surgery: the use of real-time polymerase chain reaction (PCR)

Mycoplasma hominis is a commensal of the genitourinary tract. It mostly causes infections to associated structures of this system; however, occasionally it is a pathogen in nongenitourinary tract infections. Since, M. hominis strains require special growth conditions and cannot be Gram stained, they may be missed or delay diagnosis. This report describes a deep wound infection caused by M. hominis after neuromuscular scoliosis surgery; M. hominis was recovered by real-time polymerase chain reaction (PCR). An awareness of the role of M. hominis as an extragenital pathogen in musculoskeletal infections, especially in neuromuscular scoliosis, being a high-risk group for postoperative wound infection, it is necessary to identify this pathogen. Real-time PCR for postoperative deep wound infection, in patients with a history of genitourinary infections, decreases the delay in diagnosis and treatment. In these cases rapid real-time PCR on deep cultures should be considered

Multidisciplinary outpatient care program for patients with chronic low back pain: design of a randomized controlled trial and cost-effectiveness study [ISRCTN28478651]

<p>Abstract</p> <p>Background</p> <p>Chronic low back pain (LBP) is a major public and occupational health problem, which is associated with very high costs. Although medical costs for chronic LBP are high, most costs are related to productivity losses due to sick leave. In general, the prognosis for return to work (RTW) is good but a minority of patients will be absent long-term from work. Research shows that work related problems are associated with an increase in seeking medical care and sick leave. Usual medical care of patients is however, not specifically aimed at RTW.</p> <p>The objective is to present the design of a randomized controlled trial, i.e. the BRIDGE-study, evaluating the effectiveness in improving RTW and cost-effectiveness of a multidisciplinary outpatient care program situated in both primary and outpatient care setting compared with usual clinical medical care for patients with chronic LBP.</p> <p>Methods/Design</p> <p>The design is a randomized controlled trial with an economic evaluation alongside. The study population consists of patients with chronic LBP who are completely or partially sick listed and visit an outpatient clinic of one of the participating hospitals in Amsterdam (the Netherlands). Two interventions will be compared. 1. a multidisciplinary outpatient care program consisting of a workplace intervention based on participatory ergonomics, and a graded activity program using cognitive behavioural principles. 2. usual care provided by the medical specialist, the occupational physician, the patient's general practitioner and allied health professionals. The primary outcome measure is sick leave duration until full RTW. Sick leave duration is measured monthly by self-report during one year. Data on sick leave during one-year follow-up are also requested form the employers. Secondary outcome measures are pain intensity, functional status, pain coping, patient satisfaction and quality of life. Outcome measures are assessed before randomization and 3, 6, and 12 months later. All statistical analysis will be performed according to the intension-to-treat principle.</p> <p>Discussion</p> <p>Usual care of primary and outpatient health services isn't directly aimed at RTW, therefor it is desirable to look for care which is aimed at RTW. Research shows that several occupational interventions in primary care are aimed at RTW. They have shown a significant reduction of sick leave for employee with LBP. If a comparable reduction of sick leave duration of patients with chronic LBP of who attend an outpatient clinic can be achieved, such reductions will be obviously substantial for the Netherlands and will have a considerable impact.</p> <p>Trial registration</p> <p>ISRCTN28478651</p

PLDLA mesh and 60/40 biphasic calcium phosphate in iliac crest regeneration in the goat

Although morbidity of the iliac crest after grafting has been reported to occur frequently, it is the most widely used donor site. A proper regeneration of the defect could decrease morbidity. The purpose of this study was to evaluate the efficacy of two types of reconstruction of standardized critical size defects of the iliac crest after 3, 6, and 12 months. Standardized critical defects in iliac crests were bilaterally reconstructed in 28 goats randomly with (1) no reconstruction (group A); (2) a bioresorbable polylactide mesh (group B); or (3) 60/40 biphasic calcium phosphate (BCP) granules placed within a bioresorbable mesh (group C). At follow up, the iliac crests were harvested for histologic, histomorphometric, and radiologic analyses. The defects treated with "mesh-BCP" (group C) showed a significantly (p = 0.03) larger area with diffuse bone formation, while only a small area of high density trabecular bone ingrowth was observed in the "no reconstruction" (group A) and "mesh group" (group B). However, no difference in the total volume of bone was observed; in group C, the bone was more diffusely spread over the defect. Substitution of the BCP granules by trabecular bone did not start before 6 months. At the 12 months time point, extensive resorption of BCP was found because of phagocytic activity of numerous multinucleated giant cells. We confirm the positive influence of BCP on bone formation but due to a slow rate of resorption of BCP, regeneration takes a relatively long period of tim

Four-Year Follow-Up of Poly-L-Lactic Acid Cages for Lumbar Interbody Fusion in Goats

BACKGROUND: New applications of bioabsorbable polymer implants demand for histologic evaluation because a host tissue response is elicited and late complications after polymer implantation have been reported. Furthermore, in load-bearing regions an accelerated polymer degradation and foreign body reaction may be observed. METHODS: Lumbar interbody fusion procedures were performed using poly-L-lactic acid (PLLA) and titanium cages in 43 goats. At 3, 6, 12, 24, 36, and 48 months after surgery, sequential histologic analysis of instrumented motion segments, lymph nodes, and nervous structures was performed. Blood samples were retrieved for laboratory analysis. RESULTS: No adverse local or distant histologic or systemic effects were observed during the absorption of the poly-L-lactic acid cages. Interbody fusion was maintained, and only a very mild inflammatory response was observed. In half the specimens complete absorption was observed, and in the remaining specimens an estimated 1-10% of the original PLLA was present at the 3-year follow-up. At the 4-year follow-up, five out of seven PLLA specimens showed no PLLA particles under polarized light microscopy. In the remaining two specimens an estimated 1% of the original PLLA could be observed. CONCLUSIONS: Poly-L-lactic acid cages are feasible for lumbar interbody fusion, and the biocompatibility under high load bearing conditions is excellent during the complete absorption of the PLLA interbody fusion cages

Adjacent segment degeneration: observations in a goat spinal fusion study

The adjacent discs of 13 goats, originally used in a lumbar spinal fusion model study, were analyzed for symptoms of intervertebral disc degeneration by means of magnetic resonance imaging (MRI), macroscopy, and histology. These goats were followed for 6 months and the results were compared with 6 control goats. To evaluate the development of adjacent segment disc degeneration in vivo in a goat lumbar spinal fusion model. There is ongoing debate on whether adjacent segment degeneration (ASD) develops through increased biomechanical load on discs adjacent to fusion sites, or by the natural process of pre-existing degenerative disease. Animal models offer an opportunity to separate these factors by evaluating the development of ASD in nondegenerated animal spines. In a spinal fusion model study 2 segments (L3-L4 and L1-L2) were fixated and followed for 3 months (n = 6) and 6 months (n = 7) in 13 skeletally mature goats. Two adjacent discs (T13-L1 and L4-L5), 1 interjacent disc (L2-L3) and a control disc (L5-L6) were analyzed by means of magnetic resonance imaging, macroscopy, and histology. These results were compared with the discs of 6, nonoperated "normal" goats. No differences were observed in the adjacent and interjacent intervertebral discs after both follow-up periods. However, severe degenerative changes were observed in the L5-L6 level, originally included as controls. Large animal fusion models offer an excellent opportunity to study ASD in vivo, as pre-existing degenerative disc disease is not present and biomechanical effects of the fusion can be studied more isolated. Our results suggest that adjacent disc degeneration does not develop in our spinal goat fusion model. There is, however, an increased risk of disc degeneration in the L5-L6 level through an unclear mechanis

Sterilization and strength of 70/30 polylactide cages: e-beam versus ethylene oxide

In vitro and in vivo studies on the degradation of 70/30 poly(L,DL-lactide) (PLDLLA) cages. To evaluate the effect of e-beam and ethylene oxide sterilization on degradation and strength. e-beam-sterilized PLDLLA cages were shown to maintain mechanical strength for at least 6 months during degradation studies in vitro. Yet failure of the cages was observed after only 3 months in vivo. We hypothesized that degradation characteristics and mechanical strength could be improved by sterilizing the cages through ethylene oxide (EtO) instead of e-beam. PLDLLA cages were sterilized either by e-beam or EtO, and degraded in phosphate-buffered saline. Each month, cages were compressed until failure. Inherent viscosity was determined as a measure of degradation. For the in vivo evaluation, e-beam- or EtO-sterilized cages were implanted at L3-L4 in a standardized goat model. After 3 or 6 months, retrieved segments were scanned by high-resolution magnetic resonance imaging. Also, inherent viscosity of the polymer was measured. e-beam sterilization strongly decreased inherent viscosity of PLDLLA compared with EtO sterilization, but initial strength was only affected marginally. After 6 months, the strength of the e-beam-sterilized cages dropped, while that of EtO-sterilized cages was maintained. Degradation in vivo was slightly faster than in vitro. In both groups, however, mechanical failure occurred at 3 months after implantation. Inherent viscosity decreases with degradation time, but strength only decreases when inherent viscosity is below a certain threshold. Above this threshold, mechanical strength is a property of the polymer and independent of inherent viscosity. e-beam sterilization strongly decreases inherent viscosity and thus advances mechanical degradation. EtO sterilization delays degradation but does not increase initial strength. Early failure of PLDLLA cages in the goat model thus is unrelated to sterilization method and requires further stud

Molecular changes in the degenerated goat intervertebral disc

Study Design. Caprine lumbar intervertebral discs (IVD) were collected from previous studies and categorized as normal, mildly, or severely degenerated. The biochemical composition and the RNA profiles present in both the nucleus pulposus (NP) and the anulus fibrosus (AF) were analyzed. Objective. To determine the molecular changes occurring in a disc degeneration model, evaluating the mechanism through which the degeneration develops in this model. Summary of Background Data. Recently we described an IVD degeneration model in the goat by injecting chondroitinase ABC. This results in mild progressive disc degeneration. Methods. One hundred nine caprine IVDs were assigned to 3 classes: no degeneration, mild, or severe degeneration. Collagen content, collagen cross-links (hydroxylysyl pyridinoline) and the ratio between the glycosaminoglycans (GAGs) and hydroxyprolines (Hyp) (GAG/Hyp ratio) in the NP and AF samples were studied. Furthermore, the gene expression of collagen type I, type II, and aggrecan as well as a desintegrin and metalloproteinase with thrombospondin motifs (ADAMTIS)-2, ADAMTS-14, and matrix metalloproteinases-13 were studied. Results. Collagen content was increased in severely degenerated NPs and decreased in severely degenerated AFs. Collagen cross-links were decreased in the severely degenerated NPs indicating de novo deposition of immature, reducible cross-linked collagens. The GAG/Hyp ratio found in none-degenerate goat discs was comparable to human ratios and decreased in degenerated discs, similar as in humans. The ADAMTS genes were increasingly detectable in the degenerated discs. The matrix metalloproteinases-13 gene increased significantly in degenerated discs. The expression of collagen type I increased in degenerated discs while aggrecan decreased. Conclusion. Changes in the GAG/Hyp ratio of chemically induced degeneration in goat IVD resemble the changes seen in humans. Gene expression profiles match the pattern of degeneration, suggesting that the injection of chondroitinase ABC might mimic the onset of human disc degeneratio

Comparable Efficacies of the Antimicrobial Peptide Human Lactoferrin 1-11 and Gentamicin in a Chronic Methicillin-Resistant Staphylococcus aureus Osteomyelitis Model

The therapeutic efficacy of an antimicrobial peptide, human lactoferrin 1-11 (hLF1-11), was investigated in a model of chronic methicillin-resistant Staphylococcus aureus (MRSA) (gentamicin susceptible) osteomyelitis in rabbits. We incorporated 50 mg hLF1-11/g or 50 mg gentamicin/g cement powder into a calcium phosphate bone cement (Ca-P) and injected it into the debrided tibial cavity, creating a local drug delivery system. The efficacy of hLF1-11 and gentamicin was compared to that of a sham-treated control (plain bone cement) (n = 6) and no treatment (infected only) (n = 5). The results were evaluated by microbiology, radiology, and histology. MRSA was recovered from all tibias in both control groups (n = 11). On the other hand, hLF1-11 and gentamicin significantly reduced the bacterial load. Furthermore, no growth of bacteria was detected in five out of eight and six out of eight specimens of the hLF1-11- and gentamicin-treated groups, respectively. These results were confirmed by a significant reduction of the histological disease severity score by hLF1-11 and gentamicin compared to both control groups. The hLF1-11-treated group also had a significantly lower radiological score compared to the gentamicin-treated group. This study demonstrates the efficacy of hLF1-11 incorporated into Ca-P bone cement as a possible therapeutic strategy for the treatment of osteomyelitis, showing efficacy comparable to that of gentamicin. Therefore, the results of this study warrant further preclinical investigations into the possibilities of using hLF1-11 for the treatment of osteomyelitis

Effect of long-term preservation on the mechanical properties of cortical bone in goats

Bones used in mechanical studies are frequently harvested from human cadavers that have been embalmed in a buffered formaldehyde solution. It has been reported that formaldehyde fixation or freezing hardly affects the mechanical properties of bone after a storage period of several weeks. However, human cadaver bones are usually stored for longer periods of time before use. We therefore investigated the effects of long-term embalming or freezing on the mechanical properties of cortical bone. After 5 different storage periods (ranging from 0 to 12 months), goat femora and humeri were used to evaluate the effect of embalming and freezing on torsion, and on bending stiffness and strength. The effect on hardness and bone mineral density (BMD) was also evaluated. Even after 1 year, no statistically significant differences could be found in stiffness, strength, and energy absorption when we compared embalmed or frozen bones to a fresh reference group. In addition, although we found no significant change in BMD, there appears to be a tendency to increasing hardness. We found that there was no effect on the mechanical properties of bone after storage periods of 1 year. We conclude that embalmed or frozen bones can safely be used for mechanical testing, at least for storage periods of up to one yea