The cross-sectional and longitudinal interconnectedness of physical, psychological and role functioning following physical trauma: A network analysis.

OBJECTIVE: Surviving physical trauma can have a large impact on one's daily life. Patients are at increased risk for poor physical health, psychological complaints, and problems in role functioning - which is often experienced simultaneously. The present study explores the interconnectedness of physical, psychological, and role functioning during the first two years post-injury, both cross-sectionally and longitudinally from a network perspective. METHODS: 3785 trauma patients (Mage = 64.2 years, SDage = 18.9 years, 50.5% female) completed questionnaires on physical, psychological, and role functioning across six measurement occasions during the first two years post-injury. The Injury Severity Score (ISS) was retrieved from the local trauma registry. Mixed graphical network models and cross-lagged network models were estimated to examine which items of recovery played a central role and were mostly related to other items in cross-sectional and longitudinal networks respectively. RESULTS: The cross-sectional networks showed especially strong interconnections between impairments of physical and role functioning and also within post-traumatic stress symptoms. The longitudinal networks extended these results by showing that pain, impaired mobility, limitations in self-care, anxiety/depressive symptoms, and several post-traumatic stress symptoms were strong predictors for impairments in functioning at later stages of recovery. CONCLUSION: Our findings showed that impairments in physical, psychological, and role functioning experienced by trauma patients are largely intertwined across the two years following injury. Monitoring physical impairments and psychological complaints early in recovery might help to more promptly provide the best fitting aftercare for trauma patients, which can improve recovery on the long-term.

A simplified, 2-question grading system for evaluating abstracts in orthopedic scientific meetings: a serial randomization study.

BACKGROUND AND PURPOSE: Efficient abstract scoring for congress presentation is important. Given the emergence of new study methodologies, a scoring system that accommodates all study designs is warranted. We aimed to assess the equivalence of a simplified, 2-question abstract grading system with a more complex currently used system in assessing abstracts submitted for orthopedic scientific meetings in a serial randomized study. METHODS: Dutch Orthopedic Association Scientific Committee (DOASC) members were randomized to grade abstracts using either the current grading system, which includes up to 7 scoring categories, or the new grading system, which consists of only 2 questions. Pearson correlation coefficient and mean abstract score with 95% confidence intervals (CI) were calculated. RESULTS: Analysis included the scoring of 195 abstracts by 12-14 DOASC members. The average score for an abstract using the current system was 60 points (CI 58-62), compared with 63 points (CI 62-64) using the new system. By using the new system, abstracts were scored higher by 3.3 points (CI 1.7-5.0). Pearson correlation was poor with coefficient 0.38 (P < 0.001). CONCLUSION: The simplified abstract grading system exhibited a poor correlation with the current scoring system, while the new system offers a more inclusive evaluation of varying study designs and is preferred by almost all DOASC members.

Translation and validation of the Dutch Spine Oncology Study Group Outcomes Questionnaire (SOSGOQ2.0) to evaluate health-related quality of life in patients with symptomatic spinal metastases.

BACKGROUND: The primary goal of palliative treatment of spinal metastases is to maintain or improve health-related quality of life (HRQOL). We translated and validated a Dutch version of The Spine Oncology Study Group Outcome Questionnaire (SOSGOQ2.0), a valid and reliable 20-item questionnaire to evaluate HRQOL in patients with spinal metastases. METHODS: After cross-cultural translation and adaptation, the questionnaire was pre-tested in fifteen patients referred for spine surgery and/or radiotherapy. This resulted in a final questionnaire that was sent to patients for assessment of internal consistency, construct (i.e., convergent and divergent) validity, discriminative power and test-retest reliability. RESULTS: Overall, 147 patients (mean age 65.6 years, SD = 10.4) completed the questionnaire after a median time of 45.4 months (IQR = 18.9-72.9) after spine surgery and/or radiotherapy. Internal consistency was good for the Physical function, Pain, and Mental health domains (α = 0.87, 0.86, 0.72), but not for Social function (α = 0.04). Good convergent validity was demonstrated except for Social function (rs = 0.37 95%CI = 0.21-0.51). Discriminative power between patients with ECOG performance scores of 0-1 and 2-4 was found on all domains and Neurological function items. Test-retest reliability was acceptable for Physical function, Pain and Mental health (ICC = 0.89 95%CI = 0.81-0.94, ICC = 0.88 95%CI = 0.78-0.93, ICC = 0.68 95%CI = 0.48-0.81), whereas ICC = 0.45 (95%CI = 0.17-0.66) for Social function was below threshold. After removing item 20 from the Social function domain, internal consistency improved, and convergent validity and test-retest reliability were good. CONCLUSION: The Dutch version of the SOSGOQ2.0 questionnaire is a reliable and valid tool to measure HRQOL in patients with spinal metastases. Item 20 was removed to retain psychometric properties.

No added value of 2-year radiographic follow-up of fusion surgery for adolescent idiopathic scoliosis.

PURPOSE: For fusion surgery in adolescent idiopathic scoliosis (AIS) consensus exists that a 2-year radiographic follow-up assessment is needed. This standard lacks empirical evidence. The purpose of this study was to investigate the radiographic follow-up after corrective surgery in AIS, from pre-until 2 years postoperative. METHODS: In this historical cohort study, 63 patients surgically treated for AIS, age ≤ 25 years, with 2-year radiographic follow-up, were enrolled. The primary outcome measure was the major Cobb angle. Secondary outcomes were coronal and sagittal spino-pelvic parameters, including proximal junction kyphosis (PJK) and distal adding-on. Change over time was analyzed using a repeated measures ANOVA. RESULTS: The major curve Cobb angle showed a statistically significant change for pre- to 1 year postoperative, but not for 1- to 2-year follow-up. Seven out of 63 patients did show a change exceeding the error of measurement (5°) from 1- to 2-year follow-up (range -8° to +7°), of whom 2 patients showed curve progression and 5 showed improvement. PJK or distal adding-on was not observed. CONCLUSIONS: No statistically significant changes in major curve Cobb angle were found during postsurgical follow-up, or in adjacent non-fused segments. The findings of this study are not supportive for routine radiographs 2 years after fusion surgery in AIS patients.

Gene delivery of bone morphogenetic protein-2 plasmid DNA promotes bone formation in a large animal model.

In the field of bone regeneration, BMP-2 is considered one of the most important growth factors because of its strong osteogenic activity, and is therefore extensively used in clinical practice. However, the short half-life of BMP-2 protein necessitates the use of supraphysiological doses, leading to severe side-effects. This study investigated the efficiency of bone formation at ectopic and orthotopic sites as a result of a low-cost, prolonged presence of BMP-2 in a large animal model. Constructs consisting of alginate hydrogel and BMP-2 cDNA, together acting as a non-viral gene-activated matrix, were combined with goat multipotent stromal cells (gMSCs) and implanted in spinal cassettes or, together with ceramic granules, intramuscularly in goats, both for 16 weeks. Bone formation occurred in all cell-seeded ectopic constructs, but the constructs containing both gMSCs and BMP-2 plasmid DNA showed higher collagen I and bone levels, indicating an osteogenic effect of the BMP-2 plasmid DNA. This was not seen in unseeded constructs, even though transfected, BMP-2-producing cells were detected in all constructs containing plasmid DNA. Orthotopic constructs showed mainly bone formation in the unseeded groups. Besides bone, calcified alginate was present in these groups, acting as a surface for new bone formation. In conclusion, transfection of seeded or resident cells from this DNA delivery system led to stable expression of BMP-2 during 16 weeks, and promoted osteogenic differentiation and subsequent bone formation in cell-seeded constructs at an ectopic location and in cell-free constructs at an orthotopic location in a large animal model.

A differential effect of bone morphogenetic protein-2 and vascular endothelial growth factor release timing on osteogenesis at ectopic and orthotopic sites in a large-animal model.

In bone tissue engineering, growth factors are widely used. Bone morphogenetic proteins (BMPs) and vascular endothelial growth factor (VEGF) are the most well-known regulators of osteogenesis and angiogenesis. We investigated whether the timing of dual release of VEGF and BMP-2 influences the amount of bone formation in a large-animal model. Poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) were loaded with BMP-2 or VEGF to create sustained-release profiles, and rapidly degrading gelatin was loaded with either growth factor for fast-release profiles. To study in vivo osteogenicity, the two delivery vehicles were combined with biphasic calcium phosphate (BCP) scaffolds and implanted in 10 Beagle dogs for 9 weeks, at both ectopic (paraspinal muscles) and orthotopic sites (critical-size ulnar defect). The 9 ectopic groups contained combined or single BMP/VEGF dosage, in sustained- or fast-release profiles. In the ulnae of 8 dogs, fast VEGF and sustained BMP-2 were applied to one leg, and the other received the opposite release profiles. The two remaining dogs received bilateral control scaffolds. Bone growth dynamics was analyzed by fluorochrome injection at weeks 3, 5, and 7. Postoperative and posteuthanization X-rays of the ulnar implants were taken. After 9 weeks of implantation, bone quantity and bone growth dynamics were studied by histology, histomorphometry, and fluorescence microscopy. The release of the growth factors resulted in both enhanced orthotopic and ectopic bone formation. Bone formation started before 3 weeks and continued beyond 7 weeks. The ectopic BMP-2 fast groups showed significantly more bone compared to sustained release, independent of the VEGF profile. The ulna implants revealed no significant differences in the amount of bone formed. This study shows that timing of BMP-2 release largely determines speed and amount of ectopic bone formation independent of VEGF release. Furthermore, at the orthotopic site, no significant effect on bone formation was found from a timed release of growth factors, implicating that timed-release effects are location dependent.

Luciferase labeling for multipotent stromal cell tracking in spinal fusion versus ectopic bone tissue engineering in mice and rats.

Tissue engineering of bone, by combining multipotent stromal cells (MSCs) with osteoconductive scaffolds, has not yet yielded any clinically useful applications so far. The fate and contribution of the seeded cells are not sufficiently clarified, especially at clinically relevant locations. Therefore, we investigated cell proliferation around the spine and at ectopic sites using noninvasive in vivo bioluminescence imaging (BLI) in relation to new bone formation. Goat MSCs were lentivirally transduced to express luciferase. After showing both correlation between MSC viability and BLI signal as well as survival and osteogenic capacity of these cells ectopically in mice, they were seeded on ceramic scaffolds and implanted in immunodeficient rats at two levels in the spine for spinal fusion as well as subcutaneously. Nontransduced MSCs were used as a control group. All rats were monitored at day 1 and after that weekly until termination at week 7. In mice a BLI signal was observed during the whole observation period, indicating survival of the seeded MSCs, which was accompanied by osteogenic differentiation in vivo. However, these same MSCs showed a different response in the rat model, where the BLI signal was present until day 14, both in the spine and ectopically, indicating that MSCs were able to survive at least 2 weeks of implantation. Only when the signal was still present after the total implantation period ectopically, which only occurred in one rat, new bone was formed extensively and the implanted MSCs were responsible for this bone formation. Ectopically, neither a reduced proliferative group (irradiated) nor a group in which the cells were devitalized by liquid nitrogen and the produced extracellular matrix remained (matrix group) resulted in bone formation. This suggests that the release of soluble factors or the presence of an extracellular matrix is not enough to induce bone formation. For the spinal location, the question remains whether the implanted MSCs contribute to the bone regeneration or that the principal mechanism of MSC activity is through the release of soluble mediators.

Use of fluorochrome labels in in vivo bone tissue engineering research.

The use of fluorochromes in bone research is a widely accepted technique that dates back to the 1950s. Several pioneers, such as Harold Frost, have thoroughly investigated the potential of fluorochrome use for the study on bone formation and bone remodeling dynamics. Since the development of bone tissue engineering, a renewed interest in the benefits of fluorochrome use was perceived. Fluorochrome use in animal models makes it possible to determine the onset time and location of osteogenesis, which are the fundamental parameters in bone tissue engineering studies. There is, however, a lack of standardized procedures for using this technique. In addition, many types of fluorochromes exist and one could be confused upon selecting the appropriate type, the appropriate concentration, the route of administration, and methods of visualization. All these variables can potentially affect the outcome during fluorescence microscopy. This work aims at providing the bone tissue engineering researcher with an overview of the history, working mechanism, and the potential pitfalls in the use of fluorochromes in animal studies. Experiments using some of the more frequently used fluorochromes are explained and illustrated.

Influence of endothelial progenitor cells and platelet gel on tissue-engineered bone ectopically in goats.

For the development of functional large bone tissue constructs, optimal oxygen and nutrients supply of seeded multipotent stromal cells (MSCs) is likely dependent on vascularization. The introduction of endothelial progenitor cells (EPCs) to MSC cultures might enhance vascularization and therefore increase bone formation. In this study we cocultured MSCs and EPCs and investigated performance and bone formation both in vitro and in vivo. The EPCs used were characterized by uptake of acetylated low-density lipoproteins, binding of isolectin B4 and expression of platelet endothelial cell adhesion molecule. EPC/MSC in vitro coculture showed that both cell types exerted a positive effect on proliferation of the other. For the in vivo studies, we applied platelet-leukocyte gel (PLG), containing several growth factors, as a means to further induce vascularization and thereby enhance bone formation. Cocultures and monocultures were combined with either PLG or plasma, seeded on ceramic scaffolds, and implanted intramuscularly in nine goats. After 16 weeks of implantation, it turned out that seeding MSCs and EPCs both resulted in significant more bone lining the scaffold than the unseeded controls, and MSCs and cocultures with highest MSC/EPC ratio were most competent. Cocultures did not show a higher bone content than the monoculture of MSCs. Fluorochrome incorporation results showed that the presence of seeded cells, either MSCs or EPCs, in the constructs accelerated bone formation. Finally, the addition of PLG instead of plasma did have a positive influence on the quantity of incorporated bone.

Orthotopic location has limited benefit from allogeneic or autologous multipotent stromal cells seeded on ceramic scaffolds.

Improvement of tissue-engineered grafts is still a challenge in the field of regenerative medicine. Using multipotent stromal cells (MSCs), which have immunosuppressive qualities in an allogeneic situation, off-the-shelf implants can be created. This study compared allogeneic and autologous MSCs at an orthotopic (L1 transverse process model) and ectopic (intramuscular) implantation location in 2-year-old goats. Further, the possible additional effect of platelet-leukocyte gel (PLG) as a source of growth factors on bone formation was investigated. For the orthotopic implantation, cassettes were implanted in nine goats bilaterally on the lumbar transverse processes, either with PLG-seeded or with plasma-seeded constructs. To assess the onset of bone formation, fluorochromes were administered at weeks 3, 5, and 9. Their incorporation in newly formed bone indicated that seeded cells enhanced bone formation in the first weeks. Nevertheless, after 16 weeks no beneficial effects of cells were found in the cassettes in contrast to the ectopic location. No effect of PLG on bone formation was shown at either location. Finally, we show no significant difference in bone formation between autologous and allogeneic MSCs, an important finding when considering the use of allogeneic cells as an off-the-shelf component in tissue-engineered bone in goats.

Comparing various off-the-shelf methods for bone tissue engineering in a large-animal ectopic implantation model: bone marrow, allogeneic bone marrow stromal cells, and platelet gel.

Construction of bone grafts for regenerative medicine would highly benefit from off-the-shelf components, such as allogeneic bone marrow stromal cells (BMSCs) and blood-derived growth factors from platelet concentrate. Although allogeneic BMSCs are considered immunosuppressive, their use in transplantation studies is still cautioned. In this study, we used off-the-shelf goat allogeneic BMSCs, per-operatively aspirated bone marrow (BM) and platelet gel (PLG). Ten goats received six different hybrid constructs consisting of biphasic calcium phosphate scaffolds seeded with PLG or plasma that were mixed with BM, allogeneic BMSCs or left without cells. All constructs were implanted in the paraspinal muscles for 9 weeks. Fluorochromes were administered at 2, 3, and 5 weeks to assess onset of bone formation. Analysis revealed that the scaffolds without cells yielded small amounts of bone. Allogeneic BMSCs had a positive effect on the amount and early onset of bone formation. Fresh BM did not enhance ectopic bone formation. The PLG, which contained higher levels of transforming growth factor beta than plasma, did not result in more bone either. Fluorochrome incorporation results indicate that the presence of seeded cells in the constructs accelerates bone formation. This study shows a potential role of allogeneic BMSCs in bone tissue-engineering research.