Associations of Lifelong Exercise Characteristics With Valvular Function and Aortic Diameters in Patients With a Bicuspid Aortic Valve.

BACKGROUND: The potential impact of exercise on valvular function and aortic diameters in patients with a bicuspid aortic valve remains unclear. Therefore, we assessed the association between lifelong exercise characteristics, valvular dysfunction, and aortic dilatation in patients with a bicuspid aortic valve. METHODS AND RESULTS: In this cross-sectional study, exercise volume (metabolic equivalent of task minutes per week), exercise intensity, and sport type were determined from the age of 12 years to participation using a validated questionnaire. Echocardiography was used to assess aortic stenosis or aortic regurgitation and to measure diameters at the sinuses of Valsalva and ascending aorta. Aortic dilatation was defined as a Z-score ≥2. Four hundred and seven patients (42±17 years, 60% men) were included, of which 133 were sedentary (<500 metabolic equivalent of task minutes per week), 94 active (500-1000 metabolic equivalent of task minutes per week), and 180 highly active (≥1000 metabolic equivalent of task minutes per week). Moderate-to-severe aortic stenosis or aortic regurgitation was present in 23.7% and 20.0%, respectively. Sinuses of Valsalva and ascending aorta diameters were 34.8±6.6 and 36.5±8.1 mm, whereas aortic dilatation was found in 21.6% and 53.4%, respectively. Exercise volume was not associated with valve dysfunction or aortic dilatation. Vigorous intensity and mixed sports were associated with a lower prevalence of aortic stenosis (adjusted odds ratios, 0.43 [0.20-0.94] and adjusted odds ratios, 0.47 [0.23-0.95]). Exercise intensity and sport type were not associated with aortic regurgitation and aortic dilatation. CONCLUSIONS: We found no deleterious associations between lifelong exercise characteristics, valvular dysfunction, and aortic dilatation in patients with a bicuspid aortic valve. Vigorous intensity and exercise in mixed sports were associated with a lower prevalence of moderate-to-severe aortic stenosis. These observations suggest that lifelong exercise does not appear to induce adverse cardiovascular effects in patients with a bicuspid aortic valve.

Personalised electronic health programme for recovery after major abdominal surgery: a multicentre, single-blind, randomised, placebo-controlled trial.

BACKGROUND: Despite the adoption of minimally invasive techniques, recovery after abdominal surgery takes a long time. Electronic health (eHealth) modalities can provide guidance to patients, facilitating early return to normal activities. We aimed to assess the impact of a personalised eHealth programme on patients' return to normal activities after major abdominal surgery. METHODS: This single-blind, randomised, placebo-controlled trial was done at 11 teaching hospitals in the Netherlands. Eligible participants were aged 18-75 years who underwent a laparoscopic or open colectomy or hysterectomy. An independent researcher randomly allocated participants (in a 1:1 ratio) to either the intervention or control group by use of computer-based randomisation lists, with stratification by sex, type of surgery, and hospital. Participants in the intervention group had access to a perioperative, personalised eHealth programme consisting of both standard face-to-face care and eHealth, that comprised interactive tools offering goal attainment and a personalised outcome measurement, which managed recovery expectations and provided postoperative guidance tailored to each patient. Patients were provided with an activity tracker and had access to a website and mobile app with an electronic consultation (eConsult) functionality. The control group received standard care and access to a placebo website containing recovery advice provided by the hospital. The primary outcome was the number of days between surgery and personalised return to normal activities, assessed with Kaplan-Meier curves. Intention-to-treat and per-protocol analyses were done with a Cox regression model. This trial is registered with the Netherlands National Trial Register (NTR5686). FINDINGS: Between Feb 11, 2016, and Aug 9, 2017, 355 participants were randomly assigned to the intervention (n=178) or control (n=177) groups. 342 participants were included in the intention-to-treat analysis. The median time until return to normal activities was 52 days (IQR 33-111) in the intervention group, and 65 days (39-152) in the control group (adjusted hazard ratio 1·30 [95% CI 1·03-1·64]; p=0·027). The frequency of postoperative complications did not differ between groups. INTERPRETATION: This eHealth programme, delivering personalised care based on goal attainment scaling, enabled patients to return to their normal activities 13 days earlier than those who received standard care. FUNDING: ZonMw.

Diagnostic accuracy of a dual-energy computed tomography-based post-processing method for imaging bone marrow edema following an acute ligamentous knee injury.

OBJECTIVE: This study evaluated the ability of a custom dual-energy CT (DECT) post-processing material decomposition method to image bone marrow edema after acute knee injury. Using an independent validation cohort, the DECT method was compared to gold-standard, fluid-sensitive MRI. By including both quantitative voxel-by-voxel validation outcomes and semi-quantitative radiologist scoring-based assessment of diagnostic accuracy, we aimed to provide insight into the relationship between quantitative metrics and the clinical utility of imaging methods. MATERIALS AND METHODS: Images from 35 participants with acute anterior cruciate ligament injuries were analyzed. DECT material composition was applied to identify bone marrow edema, and the DECT result was quantitatively compared to gold-standard, registered fluid-sensitive MRI on a per-voxel basis. In addition, two blinded readers rated edema presence in both DECT and fluid-sensitive MR images for evaluation of diagnostic accuracy. RESULTS: Semi-quantitative assessment indicated sensitivity of 0.67 and 0.74 for the two readers, respectively, at the tibia and 0.55 and 0.57 at the femur, and specificity of 0.87 and 0.89 for the two readers at the tibia and 0.58 and 0.89 at the femur. Quantitative assessment of edema segmentation accuracy demonstrated mean dice coefficients of 0.40 and 0.16 at the tibia and femur, respectively. CONCLUSION: The custom post-processing-based DECT method showed similar diagnostic accuracy to a previous study that assessed edema associated with ligamentous knee injury using a CT manufacturer-provided, built-in edema imaging application. Quantitative outcome measures were more stringent than semi-quantitative scoring methods, accounting for the low mean dice coefficient scores.

Independent changes in bone mineralized and marrow soft tissues following acute knee injury require dual-energy or high-resolution computed tomography for accurate assessment of bone mineral density and stiffness.

Musculoskeletal injuries often induce local accumulation of blood and/or fluid within the bone marrow, which is detected on medical imaging as edema-like marrow signal intensities (EMSI). In addition to its biological effects on post-injury recovery, the displacement of low-attenuating, largely adipocytic marrow by EMSI may introduce errors into quantitative computed tomography (QCT) measurements of bone mineral density (vBMD) and resulting bone stiffness estimates from image-based finite element (FE) analysis. We aimed to investigate the impact of post-injury changes in marrow soft tissue composition on CT-based bone measurements by applying CT imaging at multiple spatial resolutions. To do so, dual energy QCT (DECT) material decomposition was used to detect EMSI in the tibiae of nineteen participants with a recent anterior cruciate ligament tear. We then measured bone density and FE-based apparent modulus within the EMSI region and in a matched volume in the uninjured contralateral knee. Three measurement methods were applied: 1.) standard, QCT density calibration and density-based FEM; 2.) a DECT density calibration that provides density measurements adjusted for marrow soft tissues; and 3.) high-resolution peripheral QCT (HR-pQCT) density and microFE analyses. When measured using standard, single-energy QCT, vBMD and apparent modulus were elevated in the EMSI compared to the contralateral. After adjusting for marrow soft tissue composition using DECT, these measurements were no longer different between the two regions. By allowing for high-resolution, localized density analysis, HR-pQCT indicated that trabecular tissue mineral density was 9 mgHA/cm3 lower, while density of marrow soft tissues was 18 mgHA/cm3 higher, in the EMSI than the contralateral region, suggesting that EMSI have opposite effects on the measured density of trabecular bone and the underlying soft marrow. Thus, after an acute injury, altered composition of marrow soft tissues may artificially inflate overall measurements of bone density and apparent modulus obtained using standard QCT. This can be corrected by accounting for marrow soft tissue attenuation, either by using DECT-based density calibration or HR-pQCT microFE and measurements of local density of trabeculae.

Maternal bone adaptation to mechanical loading during pregnancy, lactation, and post-weaning recovery.

The maternal skeleton undergoes dramatic bone loss during pregnancy and lactation, and substantial bone recovery post-weaning. The structural adaptations of maternal bone during reproduction and lactation exert a better protection of the mechanical integrity at the critical load-bearing sites, suggesting the importance of physiological load-bearing in regulating reproduction-induced skeletal alterations. Although it is suggested that physical exercise during pregnancy and breastfeeding improves women's physical and psychological well-being, its effects on maternal bone health remain unclear. Therefore, the objective of this study was to investigate the maternal bone adaptations to external mechanical loading during pregnancy, lactation, and post-weaning recovery. By utilizing an in vivo dynamic tibial loading protocol in a rat model, we demonstrated improved maternal cortical bone structure in response to dynamic loading at tibial midshaft, regardless of reproductive status. Notably, despite the minimal loading responses detected in the trabecular bone in virgins, rat bone during lactation experienced enhanced mechano-responsiveness in both trabecular and cortical bone compartments when compared to rats at other reproductive stages or age-matched virgins. Furthermore, our study showed that the lactation-induced elevation in osteocyte peri-lacunar/canalicular remodeling (PLR) activities led to enlarged osteocyte lacunae. This may result in alterations in interstitial fluid flow-mediated mechanical stimulation on osteocytes and an elevation in solute transport through the lacunar-canalicular system (LCS) during high-frequency dynamic loading, thus enhancing mechano-responsiveness of maternal bone during lactation. Taken together, findings from this study provide important insights into the relationship between reproduction- and lactation-induced skeletal changes and external mechanical loading, emphasizing the importance of weight-bearing exercise on maternal bone health during reproduction and postpartum.

A quantitative assessment of dual energy computed tomography-based material decomposition for imaging bone marrow edema associated with acute knee injury.

PURPOSE: This study developed methods to quantify and improve the accuracy of dual-energy CT (DECT)-based bone marrow edema imaging using a clinical CT system. Objectives were: (a) to quantitatively compare DECT with gold-standard, fluid-sensitive MRI for imaging of edema-like marrow signal intensity (EMSI) and (b) to identify image analysis parameters that improve delineation of EMSI associated with acute knee injury on DECT images. METHODS: DECT images from ten participants with acute knee injury were decomposed into estimated fractions of bone, healthy marrow, and edema based on energy-dependent differences in tissue attenuation. Fluid-sensitive MR images were registered to DECT for quantitative, voxel-by-voxel comparison between the two modalities. An optimization scheme was developed to find attenuation coefficients for healthy marrow and edema that improved EMSI delineation, compared to MRI. DECT method accuracy was evaluated by measuring dice coefficients, mutual information, and normalized cross correlation between the DECT result and registered MRI. RESULTS: When applying the optimized three-material decomposition method, dice coefficients for EMSI identified through DECT vs MRI were 0.32 at the tibia and 0.13 at the femur. Optimization of attenuation coefficients improved dice coefficient, mutual information, and cross-correlation between DECT and gold-standard MRI by 48%-107% compared to three-material decomposition using non-optimized parameters, and improved mutual information and cross-correlation by 39%-58% compared to the manufacturer-provided two-material decomposition. CONCLUSIONS: This study quantitatively evaluated the performance of DECT in imaging knee injury-associated EMSI and identified a method to optimize DECT-based visualization of complex tissues (marrow and edema) whose attenuation parameters cannot be easily characterized. Further studies are needed to improve DECT-based EMSI imaging at the femur.

Peak trabecular bone microstructure predicts rate of estrogen-deficiency-induced bone loss in rats.

Postmenopausal osteoporosis affects a large number of women worldwide. Reduced estrogen levels during menopause lead to accelerated bone remodeling, resulting in low bone mass and increased fracture risk. Both peak bone mass and the rate of bone loss are important predictors of postmenopausal osteoporosis risk. However, whether peak bone mass and/or bone microstructure directly influence the rate of bone loss following menopause remains unclear. Our study aimed to establish the relationship between peak bone mass/microstructure and the rate of bone loss in response to estrogen deficiency following ovariectomy (OVX) surgery in rats of homogeneous background by tracking the skeletal changes using in vivo micro-computed tomography (µCT) and three-dimensional (3D) image registrations. Linear regression analyses demonstrated that the peak bone microstructure, but not peak bone mass, was highly predictive of the rate of OVX-induced bone loss. In particular, the baseline trabecular thickness was found to have the highest correlation with the degree of OVX-induced bone loss and trabecular stiffness reduction. Given the same bone mass, the rats with thicker baseline trabeculae had a lower rate of trabecular microstructure and stiffness deterioration after OVX. Moreover, further evaluation to track the changes within each individual trabecula via our novel individual trabecular dynamics (ITD) analysis suggested that a trabecular network with thicker trabeculae is less likely to disconnect or perforate in response to estrogen deficiency, resulting a lower degree of bone loss. Taken together, these findings indicate that the rate of estrogen-deficiency-induced bone loss could be predicted by peak bone microstructure, most notably the trabecular thickness. Given the same bone mass, a trabecular bone phenotype with thin trabeculae may be a risk factor toward accelerated postmenopausal bone loss.

Reproducibility and Radiation Effect of High-Resolution In Vivo Micro Computed Tomography Imaging of the Mouse Lumbar Vertebra and Long Bone.

A moderate radiation dose, in vivo µCT scanning protocol was developed and validated for long-term monitoring of multiple skeletal sites (femur, tibia, vertebra) in mice. A customized, 3D printed mouse holder was designed and utilized to minimize error associated with animal repositioning, resulting in good to excellent reproducibility in most cortical and trabecular bone microarchitecture and density parameters except for connectivity density. Repeated in vivo µCT scans of mice were performed at the right distal femur and the 4th lumbar vertebra every 3 weeks until euthanized at 9 weeks after the baseline scan. Comparing to the non-radiated counterparts, no radiation effect was found on trabecular bone volume fraction, osteoblast and osteoblast number/surface, or bone formation rate at any skeletal site. However, trabecular number, thickness, and separation, and structure model index were sensitive to ionizing radiation associated with the µCT scans, resulting in subtle but significant changes over multiple scans. Although the extent of radiation damage on most trabecular bone microarchitecture measures are comparable or far less than the age-related changes during the monitoring period, additional considerations need to be taken to minimize the confounding radiation factors when designing experiments using in vivo µCT imaging for long-term monitoring of mouse bone.

Associations Between Breastfeeding History and Early Postmenopausal Bone Loss.

This study aimed to evaluate associations of parity and breastfeeding history with postmenopausal bone loss. Early postmenopausal women from the Canadian Multicentre Osteoporosis Study were divided into three groups based on their reproductive histories: nulliparous (NP, n = 10), parous with < 6 months breastfeeding (P-NBF, n = 14), and parous with > 6 months breastfeeding (P-BF, n = 21). Women underwent dual X-ray absorptiometry and high-resolution peripheral quantitative computed tomography imaging at baseline and after 6 years to evaluate bone mineral density (BMD), bone microstructure, and finite element-estimated failure load. Average age at baseline was 57 years. Baseline density, microstructure, and failure load were not different among groups. In all women, total and cortical BMD decreased significantly at the tibia and radius. P-BF women only experienced a significant decline in tibial trabecular BMD, with a greater magnitude of change for P-BF than NP women (p = 0.002). Overall, results suggest that early postmenopausal bone health did not differ based on parity or breastfeeding history. Over the 6-year follow-up period, postmenopausal bone loss was evident in all women, with subtle differences in the rate of postmenopausal change among women with varying breastfeeding histories. Parous women who had breastfed for at least 6 months showed an elevated rate of trabecular BMD loss at the tibia. Meanwhile, correlation analyses suggest that longer durations of breastfeeding may be associated with reduced cortical bone loss at the radius. The lack of differences among groups in FE-derived failure load suggests that parity and breastfeeding history is unlikely to significantly affect postmenopausal risk of fracture.

Mechanical Regulation of the Maternal Skeleton during Reproduction and Lactation.

PURPOSE OF REVIEW: This review summarizes recently published data on the effects of pregnancy and lactation on bone structure, mechanical properties, and mechano-responsiveness in an effort to elucidate how the balance between the structural and metabolic functions of the skeleton is achieved during these physiological processes. RECENT FINDINGS: While pregnancy and lactation induce significant changes in bone density and structure to provide calcium for fetal/infant growth, the maternal physiology also comprises several innate compensatory mechanisms that allow for the maintenance of skeletal mechanical integrity. Both clinical and animal studies suggest that pregnancy and lactation lead to adaptations in cortical bone structure to allow for rapid calcium release from the trabecular compartment while maintaining whole bone stiffness and strength. Moreover, extents of lactation-induced bone loss and weaning-induced recovery are highly dependent on a given bone's load-bearing function, resulting in better protection of the mechanical integrity at critical load-bearing sites. The recent discovery of lactation-induced osteocytic perilacunar/canalicular remodeling (PLR) indicates a new means for osteocytes to modulate mineral homeostasis and tissue-level mechanical properties of the maternal skeleton. Furthermore, lactation-induced PLR may also play an important role in maintaining the maternal skeleton's load-bearing capacity by altering osteocyte's microenvironment and modulating the transmission of anabolic mechanical signals to osteocytes. Both clinical and animal studies show that parity and lactation have no adverse, or a positive effect on bone strength later in life. The skeletal effects during pregnancy and lactation reflect an optimized balance between the mechanical and metabolic functions of the skeleton.

[Non-metastatic oesophageal cancer: diagnosis and treatment]. / Niet-gemetastaseerde slokdarmkanker.

The incidence of oesophageal cancer is on the rise, particularly due to an increase in the number of adenocarcinomas of the distal oesophagus. Adenomas and squamous cell carcinomas are the most common histological subtypes; each should be considered as a different entity. The diagnosis 'oesophageal cancer' is confirmed on the basis of histopathological investigation of biopsies, whereas tumour staging is conducted through transoesophageal endoscopic ultrasound and FDG-PET/CT diagnostics. There are various options to treat patients with oesophageal cancer, such as endoscopic resection, multimodal therapy or definitive chemoradiotherapy. Since 2012, neoadjuvant chemoradiotherapy followed by surgery is the standard treatment for oesophageal cancer, except with regard to patients with a T1 or M1 tumour. In the Netherlands, most surgical procedures are now minimally invasive procedures. Despite improved treatment options, mortality rates associated with oesophageal cancer remain high.

Electronic Health Program to Empower Patients in Returning to Normal Activities After General Surgical and Gynecological Procedures: Intervention Mapping as a Useful Method for Further Development.

BACKGROUND: Support for guiding and monitoring postoperative recovery and resumption of activities is usually not provided to patients after discharge from the hospital. Therefore, a perioperative electronic health (eHealth) intervention ("ikherstel" intervention or "I recover" intervention) was developed to empower gynecological patients during the perioperative period. This eHealth intervention requires a need for further development for patients who will undergo various types of general surgical and gynecological procedures. OBJECTIVE: This study aimed to further develop the "ikherstel" eHealth intervention using Intervention Mapping (IM) to fit a broader patient population. METHODS: The IM protocol was used to guide further development of the "ikherstel" intervention. First, patients' needs were identified using (1) the information of a process evaluation of the earlier performed "ikherstel" study, (2) a review of the literature, (3) a survey study, and (4) focus group discussions (FGDs) among stakeholders. Next, program outcomes and change objectives were defined. Third, behavior change theories and practical tools were selected for the intervention program. Finally, an implementation and evaluation plan was developed. RESULTS: The outcome for an eHealth intervention tool for patients recovering from abdominal general surgical and gynecological procedures was redefined as "achieving earlier recovery including return to normal activities and work." The Attitude-Social Influence-Self-Efficacy model was used as a theoretical framework to transform personal and external determinants into change objectives of personal behavior. The knowledge gathered by needs assessment and using the theoretical framework in the preparatory steps of the IM protocol resulted in additional tools. A mobile app, an activity tracker, and an electronic consultation (eConsult) will be incorporated in the further developed eHealth intervention. This intervention will be evaluated in a multicenter, single-blinded randomized controlled trial with 18 departments in 11 participating hospitals in the Netherlands. CONCLUSIONS: The intervention is extended to patients undergoing general surgical procedures and for malignant indications. New intervention tools such as a mobile app, an activity tracker, and an eConsult were developed. TRIAL REGISTRATION: Netherlands Trial Registry NTR5686; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=5686.

Electronic Health Program to Empower Patients in Returning to Normal Activities After Colorectal Surgical Procedures: Mixed-Methods Process Evaluation Alongside a Randomized Controlled Trial.

BACKGROUND: Long-term recovery takes longer than expected despite improved surgical techniques and Enhanced Recovery After Surgery programs. An electronic health (eHealth) care program ("ikherstel") was developed to partially substitute perioperative care for patients undergoing colorectal surgical procedures. Successfully tested eHealth programs are not always implemented in usual care, and it is, therefore, important to evaluate the process to optimize future implementation. OBJECTIVE: The aim of this study was to evaluate whether the eHealth intervention was executed as planned. METHODS: A mixed-methods process evaluation was carried out alongside a multicenter randomized controlled trial (RCT). This evaluation was performed using the Linnan and Steckler framework for the quantitative part of this study, measuring the components reach, dose delivered, dose received, fidelity, and participants' attitudes. Total implementation scores were calculated using the averaging approach, in which the sum of all data points is divided by the number of data points and the total adherence to the protocol is measured. For the qualitative part, the Unified Theory of Acceptance and Use of Technology framework was used. The quantitative data were based on participants' questionnaires, a logistic database, a weblog, and participants' medical files and were obtained by performing semistructured interviews with participants of the RCT. RESULTS: A total of 151 participants of 340 eligible patients were included in the RCT, of which 73 participants were allocated to the intervention group. On the basis of the quantitative process data, total implementation scores for the website, mobile app, electronic consult, and activity tracker were 64%, 63%, 44%, and 67%, respectively. Participants in the qualitative part experienced the program as supportive and provided guidance on their recovery process after colorectal surgery. Most frequently mentioned barriers were the limited interaction with and feedback from health care professionals and the lack of tailoring of the convalescence plan in case of a different course of recovery. CONCLUSIONS: The intervention needs more interaction with and feedback from health care professionals and needs more tailored guidance in case of different recovery or treatment courses. To ensure a successful implementation of the program in daily practice, some adjustments are required to optimize the program in a blended care form. TRIAL REGISTRATION: Netherlands Trial Registry NTR5686; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC= 5686 (Archieved by WebCite at http://www.webcitation.org/75LrJaHrr).

Definitive Chemoradiotherapy Versus Trimodality Therapy for Resectable Oesophageal Carcinoma: Meta-analyses and Systematic Review of Literature.

BACKGROUND: Standard therapy for loco-regionally advanced, resectable oesophageal carcinoma is trimodality therapy (TMT) consisting of neoadjuvant chemoradiotherapy and oesophagectomy. Evidence of survival advantage of TMT over organ-preserving definitive chemoradiotherapy (dCRT) is inconclusive. The aim of this study is to compare survival between TMT and dCRT. METHODS: A systematic review and meta-analyses were conducted. Randomised controlled trials and observational studies on resectable, curatively treated, oesophageal carcinoma patients above 18 years were included. Three online databases were searched for studies comparing TMT with dCRT. Primary outcomes were 1-, 2-, 3- and 5-year overall survival rates. Risk of bias was assessed using the Cochrane risk of bias tools for RCTs and cohort studies. Quality of evidence was evaluated according to Grading of Recommendation Assessment, Development and Evaluation. RESULTS: Thirty-two studies described in 35 articles were included in this systematic review, and 33 were included in the meta-analyses. Two-, three- and five-year overall survival was significantly lower in dCRT compared to TMT, with relative risks (RRs) of 0.69 (95% CI 0.57-0.83), 0.76 (95% CI 0.63-0.92) and 0.57 (95% CI 0.47-0.71), respectively. When only analysing studies with equal patient groups at baseline, no significant differences for 2-, 3- and 5-year overall survival were found with RRs of 0.83 (95% CI 0.62-1.10), 0.81 (95% CI 0.57-1.14) and 0.63 (95% CI 0.36-1.12). CONCLUSION: These meta-analyses do not show clear survival advantage for TMT over dCRT. Only a non-significant trend towards better survival was seen, assuming comparable patient groups at baseline. Non-operative management of oesophageal carcinoma patients might be part of a personalised and tailored treatment approach in future. However, to date hard evidence proving its non-inferiority compared to operative management is lacking.

Prognostic factors for return to work and work disability among colorectal cancer survivors; A systematic review.

BACKGROUND: Colorectal cancer is diagnosed progressively in employed patients due to screening programs and increasing retirement age. The objective of this study was to identify prognostic factors for return to work and work disability in patients with colorectal cancer. METHODS: The research protocol was published at PROSPERO with registration number CRD42017049757. A systematic review of cohort and case-control studies in colorectal cancer patients above 18 years, who were employed when diagnosed, and who had a surgical resection with curative intent were included. The primary outcome was return to work or work disability. Potentially prognostic factors were included in the analysis if they were measured in at least three studies. Risk of bias was assessed according to the QUality In Prognosis Studies tool. A qualitative synthesis analysis was performed due to heterogeneity between studies. Quality of evidence was evaluated according to Grading of Recommendation Assessment, Development and Evaluation. RESULTS: Eight studies were included with a follow-up period of 26 up to 520 weeks. (Neo)adjuvant therapy, higher age, and more comorbidities had a significant negative influence on return to work. A previous period of unemployment, extensive surgical resection and postoperative complications significantly increased the risk of work disability. The quality of evidence for these prognostic factors was considered very low to moderate. CONCLUSION: Health care professionals need to be aware of these prognostic factors to select patients eligible for timely intensified rehabilitation in order to optimize the return to work process and prevent work disability.

Effects of reproduction on sexual dimorphisms in rat bone mechanics.

Osteoporosis most commonly affects postmenopausal women. Although men are also affected, women over 65 are 6 times more likely to develop osteoporosis than men of the same age. This is largely due to accelerated bone remodeling after menopause; however, the peak bone mass attained during young adulthood also plays an important role in osteoporosis risk. Multiple studies have demonstrated sexual dimorphisms in peak bone mass, and additionally, the female skeleton is significantly altered during pregnancy/lactation. Although clinical studies suggest that a reproductive history does not increase the risk of developing postmenopausal osteoporosis, reproduction has been shown to induce long-lasting alterations in maternal bone structure and mechanics, and the effects of pregnancy and lactation on maternal peak bone quality are not well understood. This study compared the structural and mechanical properties of male, virgin female, and post-reproductive female rat bone at multiple skeletal sites and at three different ages. We found that virgin females had a larger quantity of trabecular bone with greater trabecular number and more plate-like morphology, and, relative to their body weight, had a greater cortical bone size and greater bone strength than males. Post-reproductive females had altered trabecular microarchitecture relative to virgins, which was highly similar to that of male rats, and showed similar cortical bone size and bone mechanics to virgin females. This suggests that, to compensate for future reproductive bone losses, females may start off with more trabecular bone than is mechanically necessary, which may explain the paradox that reproduction induces long-lasting changes in maternal bone without increasing postmenopausal fracture risk.

Reproduction Differentially Affects Trabecular Bone Depending on Its Mechanical Versus Metabolic Role.

During pregnancy and lactation, the maternal skeleton provides calcium for fetal/infant growth, resulting in substantial bone loss, which partially recovers after weaning. However, the amount of bone that is lost and the extent of post-weaning recovery are highly variable among different skeletal sites, and, despite persistent alterations in bone structure at some locations, reproductive history does not increase postmenopausal fracture risk. To explain this phenomenon, we hypothesized that the degree of reproductive bone loss/recovery at trabecular sites may vary depending on the extent to which the trabecular compartment is involved in the bone's load-bearing function. Using a rat model, we quantified the proportion of the load carried by the trabeculae, as well as the extent of reproductive bone loss and recovery, at two distinct skeletal sites: the tibia and lumbar vertebra. Both sites underwent significant bone loss during pregnancy and lactation, which was partially recovered post-weaning. However, the extent of the deterioration and the resumption of trabecular load-bearing capacity after weaning varied substantially. Tibial trabecular bone, which bore a low proportion of the total applied load, underwent dramatic and irreversible microstructural deterioration during reproduction. Meanwhile, vertebral trabecular bone bore a greater fraction of the load, underwent minimal deterioration in microarchitecture, and resumed its full load-bearing capacity after weaning. Because pregnancy and lactation are physiological processes, the distinctive responses to these natural events among different skeletal sites may help to elucidate the extent of the trabecular bone's structural versus metabolic functions.