Comparison of clinical outcome between surgical treatment and particle beam therapy for pelvic bone sarcomas: A retrospective multicenter study in Japan.

BACKGROUND: Few studies have compared the clinical outcomes of patients with pelvic bone sarcomas treated surgically and those treated with particle beam therapy. This is a multicenter retrospective cohort study which compared the clinical outcomes of patients with pelvic bone sarcoma who underwent surgical treatment and particle beam therapy in Japan. METHODS: A total of 116 patients with pelvic bone sarcoma treated at 19 specialized sarcoma centers in Japan were included in this study. Fifty-seven patients underwent surgery (surgery group), and 59 patients underwent particle beam therapy (particle beam group; carbon-ion radiotherapy: 55 patients, proton: four patients). RESULTS: The median age at primary tumor diagnosis was 52 years in the surgery group and 66 years in the particle beam group (P < 0.001), and the median tumor size was 9 cm in the surgery group and 8 cm in the particle beam group (P = 0.091). Overall survival (OS), local control (LC), and metastasis-free survival (MFS) rates were evaluated using the Kaplan-Meier method and compared among 116 patients with bone sarcoma (surgery group, 57 patients; particle beam group, 59 patients). After propensity score matching, the 3-year OS, LC, and MFS rates were 82.9% (95% confidence interval [CI], 60.5-93.2%), 66.0% (95% CI, 43.3-81.3%), and 78.4% (95% CI, 55.5-90.5%), respectively, in the surgery group and 64.9% (95% CI, 41.7-80.8%), 86.4% (95% CI, 63.3-95.4%), and 62.6% (95% CI, 38.5-79.4%), respectively, in the particle beam group. In chordoma patients, only surgery was significantly correlated with worse LC in the univariate analysis. CONCLUSIONS: The groups had no significant differences in the OS, LC, and MFS rates. Among the patients with chordomas, the 3-year LC rate in the particle beam group was significantly higher than in the surgery group.

Dose-Volume Parameters of Spared Magnetic Resonance Imaging-Defined Active Bone Marrow Predict Hematologic Toxicity in Pelvic Malignancies Patients Undergoing Radiotherapy: A Cohort Study.

Background: The objective of this investigation is to evaluate the superiority of dose-volume parameters relying on magnetic resonance imaging (MRI)-defined active bone marrow (ABM) over those based on total bone marrow (TBM) contoured via CT in the prediction of hematologic toxicity (HT) occurrence among patients with pelvic malignancies undergoing radiotherapy. Methods: The clinical data of 116 patients with pelvic malignancies treated with pelvic radiotherapy were analyzed retrospectively. The ABM areas on T1-weighted MRI were contoured. The statistical significance between TBM and ABM dose-volume measures was assessed through the utilization of either Student's t-test or Wilcoxon signed rank test. Logistic and linear regression models were employed to analyze the correlation between dose-volume parameters (V5-V50) and HT occurrence in pelvic ABM and TBM. Receiver operating characteristic (ROC) curves were used to compare predictors of HT2+. Results: There were significant differences in dosimetric parameters between ABM and TBM. Logistic regression analysis showed that ABM V5, ABM V10, ABM V15, ABM V20, and TBM V5 were significantly associated with the occurrence of HT2+ in pelvic malignancies. Linear regression analysis showed that ABM V5, ABM V10, and ABM V15 were significantly associated with white blood cell (WBC), absolute neutrophil count (ANC), hemoglobin (Hb), and lymphocyte (Lym) nadir. ABM V5, ABM V10, ABM V15, and ABM V30 were predictive of HT2+. Conclusions: More accurate prediction of HT in patients receiving pelvic radiotherapy may be achieved by relying on dose-volume parameters of MRI-based ABM. Further prospective studies are needed to confirm this.

Towards an optimal design of a functionally graded porous uncemented acetabular component using genetic algorithm.

Generation of polyethylene wear debris and peri­prosthetic bone resorption have been identified as potential causes of acetabular component loosening in Total Hip Arthroplasty. This study was aimed at optimization of a functionally graded porous acetabular component to minimize peri­prosthetic bone resorption and polyethylene liner wear. Porosity levels (porosity values at acetabular rim, and dome) and functional gradation exponents (radial and polar) were considered as the design parameters. The relationship between porosity and elastic properties were obtained from numerical homogenization. The multi-objective optimization was carried out using a non-dominated sorting genetic algorithm integrated with finite element analysis of the hemipelvises subject to various loading conditions of common daily activities. The optimal functionally graded porous designs (OFGPs -1, -2, -3, -4, -5) exhibited less strain-shielding in cancellous bone compared to solid metal-backing. Maximum bone-implant interfacial micromotions (63-68 µm) for OFGPs were found to be close to that of solid metal-backing (66 µm), which might facilitate bone ingrowth. However, OFGPs exhibited an increase in volumetric wear (3-10 %) compared to solid metal-backing. The objective functions were found to be more sensitive to changes in polar gradation exponent than radial gradation exponent, based on the Sobol' method. Considering the common failure mechanisms, OFGP-1, having highly porous acetabular rim and less porous dome, appears to be a better alternative to the solid metal-backing.

Mechanobiochemical bone remodelling around an uncemented acetabular component: influence of bone orthotropy.

Mechanical loosening of an implant is often caused by bone resorption, owing to stress/strain shielding. Adaptive bone remodelling elucidates the response of bone tissue to alterations in mechanical and biochemical environments. This study aims to propose a novel framework of bone remodelling based on the combined effects of bone orthotropy and mechanobiochemical stimulus. The proposed remodelling framework was employed in the finite element model of an implanted hemipelvis to predict evolutionary changes in bone density and associated orthotropic bone material properties. In order to account for variations in load transfer during common daily activities, several musculoskeletal loading conditions of hip joint corresponding to sitting down/up, stairs ascend/descend and normal walking were considered. The bone remodelling predictions were compared with those of isotropic strain energy density (SED)-based, isotropic mechanobiochemical and orthotropic strain-based bone remodelling formulations. Although similar trends of bone resorption were predicted by orthotropic mechanobiochemical (MBC) and orthotropic strain-based models across implanted acetabulum, more volume (10-20%) of bone elements was subjected to bone resorption for the orthotropic MBC model. Higher bone resorption (75-85%) was predicted by the orthotropic strain-based and orthotropic MBC models compared to the isotropic MBC and SED-based models. Higher bone apposition (35-160%) across the implanted acetabulum was predicted by the isotropic MBC model, compared to the SED-based model. The remodelling predictions indicated that a reduction in estrogen level might lead to an increase in bone resorption. The study highlighted the importance of including mechanobiochemical stimulus and bone anisotropy to predict bone remodelling adequately.

Recurrent benign fibrous histiocytoma of the bone benefits from denosumab followed by malignant transformation: a case report.

Benign fibrous histiocytoma of the bone (BFHB) is a rare mesenchymal tumor, representing less than 1% of all benign bone tumors. This controversial entity is characterized by a mixture of fibroblasts arranged in a storiform pattern, varying amounts of osteoclast-type giant cells and foamy macrophages. Curettage or simple resection is usually curative. However, it was reported that up to 11% of the patients suffer from relapse. Here, we report a case of malignant transformation of BFHB after long-lasting disease stabilization under denosumab therapy.

Factors influencing magnetic resonance imaging changes associated with pelvic bone injury after high-intensity focused ultrasound ablation of uterine fibroids: a retrospective case-control study.

Background: The application of high-intensity focused ultrasound (HIFU) in the treatment of uterine fibroids is becoming increasingly widespread, and postoperative collateral thermal damage to adjacent tissue has become a prominent subject of discussion. However, there is limited research related to bone injury. Therefore, the aim of this study was to investigate the potential factors influencing unintentional pelvic bone injury after HIFU ablation of uterine fibroids with magnetic resonance imaging (MRI). Methods: A total of 635 patients with fibroids treated with HIFU in the First Affiliated Hospital of Chongqing Medical University were enrolled. All patients underwent contrast-enhanced MRI (CE-MRI) pre- and post-HIFU. Based on the post-treatment MRI, the patients were divided into two groups: pelvic bone injury group and non-injury group, while the specific site of pelvic bone injury of each patient was recorded. The univariate and multivariate analyses were used to assess the correlations between the factors of fibroid features and treatment parameters and pelvic bone injury, and to further analyze the factors influencing the site of injury. Results: Signal changes in the pelvis were observed on CE-MRI in 51% (324/635) of patients after HIFU. Among them, 269 (42.4%) patients developed sacral injuries and 135 (21.3%) had pubic bone injuries. Multivariate analyses showed that patients with higher age [P=0.003; odds ratio (OR), 1.692; 95% confidence interval (CI): 1.191-2.404], large anterior side-to-skin distance of fibroid (P<0.001; OR, 2.297; 95% CI: 1.567-3.365), posterior wall fibroid (P=0.006; OR, 1.897; 95% CI: 1.204-2.989), hyperintensity on T2-weighted imaging (T2WI, P=0.003; OR, 2.125; 95% CI: 1.283-3.518), and large therapeutic dose (TD, P<0.001; OR, 3.007; 95% CI: 2.093-4.319) were at higher risk of postoperative pelvic bone injury. Further analysis of the factors influencing the site of the pelvic bone injury showed that some of the fibroid features and treatment parameters were associated with it. Moreover, some postoperative pain-related adverse events were associated with the pelvic bone injury. Conclusions: Post-HIFU treatment, patients may experience pelvic injuries to the sacrum, pubis, or a combination of both, and some of them experienced adverse events. Some fibroid features and treatment parameters are associated with the injury. Taking its influencing factors into full consideration preoperatively, slowing down treatment, and prolonging intraoperative cooling phase can help optimize treatment decisions for HIFU.

Pelvic insufficiency fractures and pelvic bone metastases after neoadjuvant (chemo)radiotherapy for rectal cancer.

BACKGROUND: Pelvic insufficiency fractures (PIFs) are a late complication of radiotherapy for pelvic malignancies. We evaluated the incidence, radiologic findings, clinical course, and outcome of PIFs in patients treated with neoadjuvant (chemo)radiotherapy ((C)RT) for rectal cancer. MATERIAL AND METHODS: Data of patients diagnosed with rectal cancer from a large teaching hospital treated from 2002 to 2012 were extracted from the Dutch Cancer Registry. All hospital records were reviewed for the diagnosis of PIFs or pelvic bone metastases. An expert radiologist reassessed all imaging procedures of the lower back, abdomen, and pelvis. RESULTS: A total of 513 rectal cancer patients were identified of whom 300 patients (58.5%) were treated with neoadjuvant (C)RT (long- vs. short-course radiotherapy: 91 patients [17.7%] vs. 209 [40.7%], respectively). Twelve PIFs were diagnosed initially according to hospital records and imaging reports of all 513 patients. These 12 patients were treated with neoadjuvant (C)RT. After reassessment of all pelvic imaging procedures done in this patient group (432 patients (84.2%)), 20 additional PIFs were detected in patients treated with neoadjuvant (C)RT, resulting in a 10.7% PIF rate in irradiated patients. One PIF was detected in the group of patients not treated with neoadjuvant (C)RT for rectal cancer. This patient had palliative radiotherapy for prostate cancer and is left out of the analysis. Median follow-up time of 32 PIF patients was 49 months. Median time between start of neoadjuvant (C)RT and diagnosis of PIF was 17 months (IQR 9-28). Overall median survival for patients with PIF was 63.5 months (IQR 44-120). CONCLUSION: PIFs are a relatively common late complication of neoadjuvant (C)RT for rectal cancer but are often missed or misdiagnosed as pelvic bone metastases. The differentiation of PIFs from pelvic bone metastases is important because of a different treatment and disease outcome.

Is a Washer a Mandatory Component in Young Trauma Patients with S1-S2 Iliosacral Screw Fixation of Posterior Pelvis Ring Injuries? A Biomechanical Study.

Background and purpose: Cannulated screws are standard implants for percutaneous fixa-tion of posterior pelvis ring injuries. The choice of whether to use these screws in combination with a washer is still undecided. The aim of this study was to evaluate the biomechanical competence of S1-S2 sacroiliac (SI) screw fixation with and without using a washer across three different screw designs. Material and Methods: Twenty-four composite pelvises were used and an SI joint injury type APC III according to the Young and Burgess classification was simulated. Fixation of the posterior pelvis ring was performed using either partially threaded short screws, fully threaded short screws, or fully threaded long transsacral screws. Biomechanical testing was performed under progressively increasing cyclic loading until failure, with monitoring of the intersegmental and bone-implant movements via motion tracking. Results: The number of cycles to failure and the corresponding load at failure (N) were significantly higher for the fully threaded short screws with a washer (3972 ± 600/398.6 ± 30.0) versus its counterpart without a washer (2993 ± 527/349.7 ± 26.4), p = 0.026. In contrast, these two parameters did not reveal any significant differences when comparing fixations with and without a washer using either partially threaded short of fully threaded long transsacral screws, p ≥ 0.359. Conclusions: From a biomechanical perspective, a washer could be optional when using partially threaded short or fully threaded long transsacral S1-S2 screws for treatment of posterior pelvis ring injuries in young trauma patients. Yet, the omission of the washer in fully threaded short screws could lead to a significant diminished biomechanical stability.

Association Between Pelvic Bone Computed Tomography-Derived Body Composition and Patient Outcomes in Older Adults With Proximal Femur Fracture.

OBJECTIVE: To investigate the association between pelvic bone computed tomography (CT)-derived body composition and patient outcomes in older adult patients who underwent surgery for proximal femur fractures. MATERIALS AND METHODS: We retrospectively identified consecutive patients aged ≥ 65 years who underwent pelvic bone CT and subsequent surgery for proximal femur fractures between July 2018 and September 2021. Eight CT metrics were calculated from the cross-sectional area and attenuation of the subcutaneous fat and muscle, including the thigh subcutaneous fat (TSF) index, TSF attenuation, thigh muscle (TM) index, TM attenuation, gluteus maximus (GM) index, GM attenuation, gluteus medius and minimus (Gmm) index, and Gmm attenuation. The patients were dichotomized using the median value of each metric. Multivariable Cox regression and logistic regression models were used to determine the association between CT metrics with overall survival (OS) and postsurgical intensive care unit (ICU) admission, respectively. RESULTS: A total of 372 patients (median age, 80.5 years; interquartile range, 76.0-85.0 years; 285 females) were included. TSF attenuation above the median (adjusted hazard ratio [HR], 2.39; 95% confidence interval [CI], 1.41-4.05), GM index below the median (adjusted HR, 2.63; 95% CI, 1.33-5.26), and Gmm index below the median (adjusted HR, 2.33; 95% CI, 1.12-4.55) were independently associated with shorter OS. TSF index (adjusted odds ratio [OR], 6.67; 95% CI, 3.13-14.29), GM index (adjusted OR, 3.45; 95% CI, 1.49-7.69), GM attenuation (adjusted OR, 2.33; 95% CI, 1.02-5.56), Gmm index (adjusted OR, 2.70; 95% CI, 1.22-5.88), and Gmm attenuation (adjusted OR, 2.22; 95% CI, 1.01-5.00) below the median were independently associated with ICU admission. CONCLUSION: In older adult patients who underwent surgery for proximal femur fracture, low muscle indices of the GM and gluteus medius/minimus obtained from their cross-sectional areas on preoperative pelvic bone CT were significant prognostic markers for predicting high mortality and postsurgical ICU admission.

The effect of radiotherapy time and dose on acute hematologic toxicity during concurrent postoperative chemoradiotherapy for early high-risk cervical cancer.

Objective: This study aims to analyze the characteristics and factors that influence acute hematological toxicity (HT) during concurrent chemoradiotherapy (CCRT) for cervical cancer, as well as to provide reference data for clinical practice. Methods: Patients with FIGO IB1-IIA2 cervical cancer who underwent CCRT from May 2018 to August 2020 were included in this study retrospectively. All patients had received external beam radiation therapy and platinum-based concurrent chemotherapy. HT was assessed according to CTCAE 5.0. The pelvic bone marrow was redrawn on the original CT images and divided into four parts: the whole pelvic bone marrow (WP-BM), iliac bone marrow (IL-BM), lower pelvic bone marrow (LP-BM), and lumbosacral bone marrow (LS-BM). The radiation dose and volume of each part of the pelvic bone marrow were recalculated in a new plan created using the original planning parameters. The corresponding dose-volume histogram (DVH) was generated to obtain the bone marrow volumes receiving 10Gy, 20Gy, 30Gy, 40Gy, 45Gy, and 50Gy. Results: In 112 patients, the incidences of grade 2 or higher leukopenia, anemia, thrombocytopenia, and neutropenia were 49.1%, 2.7%, 1.8%, and 20.5%, respectively. Leukopenia was linked to LS-V20 (r = -0.310; P = 0.006) and radiotherapy treatment lengths (days) (r = -0.416; P = 0.013). Anemia was associated with WP-V30, WP-V40, WP-V45, WP-V50, IL-V20, IL-V40, ILV45, IL-V50, LP-V30, LP-V40, LP-V45, and LP-V50 (P <0.05). Thrombocytopenia (r = -0.304, P = 0.007) and neutropenia (r = -0.368, P = 0.009) was associated only with the length of radiotherapy treatment (day). Multiple regression analysis showed that only anemia was negatively correlated with WP-V30, IL-V40, and LP-V40 (P <0.05). Conclusions: Acute HT during CCRT in early-stage high-risk cervical cancer may be related to the duration of radiotherapy and the volume of different radiotherapy doses received at different parts in the pelvic bone marrow.

Design of a functionally graded porous uncemented acetabular component: Influence of polar gradation.

The functionally graded porous metal-backed (FGPMB) acetabular component has the potential to minimize strain-shielding induced bone resorption, caused by stiffness mismatch of implant and host bone. This study is aimed at a novel design of FGPMB acetabular component, which is based on numerical investigations of the mechanical behavior of acetabular components with regard to common failure scenarios, considering various daily activities and implant-bone interface conditions. Both radial and polar functional gradations were implemented, and the effects of the polar gradation exponent on the failure criteria were evaluated. The relationships between porosity and orthotropic mechanical properties of a tetrahedron-based unit cell were obtained using a numerical homogenization method. Strain-shielding in cancellous bone was relatively lesser for the FGPMB than solid metal-backing. Few nodes around the rim were susceptible to implant-bone interfacial debonding, irrespective of the polar gradation exponent. Although the most favorable bone remodeling predictions were obtained for a polar gradation exponent of 0.1, a sudden change in the porosity was observed near the rim of FGPMB. Bone remodeling patterns were similar for polar gradation exponent of 5.0 and solid metal-backing. Moreover, the volumetric wear was maximum and minimum for polar gradation exponents of 0.1 and 5, respectively. Furthermore, the micromotions of different polar gradation exponents were within a range (20-40 µm) that might facilitate bone ingrowth. Considering common failure mechanisms, the FGPMB having polar gradation exponents in the range of 0.1-0.5 appeared to be a viable alternative to the solid acetabular component, within which a gradation exponent of 0.25 seemed the most appropriate design parameter.

A semiautomatic segmentation method framework for pelvic bone tumors based on CT-MR multimodal images.

The pelvic structure is complex and the tumor is poorly defined from the surrounding tissues. Finding the exact tumor resection margin based on the surgeon's clinical experience alone is a time-consuming and difficult task, which is a major factor leading to surgical failure. An accurate method for segmenting pelvic bone tumors is needed. In this paper, a semiautomatic segmentation method for pelvic bone tumors based on CT-MR multimodal images is presented. The method combines multiple medical prior knowledge and image segmentation algorithms. Finally, the segmentation results are visualized in three dimensions. We tested the proposed method on a collection of 10 cases (97 tumor MR images in total). The segmentation results were compared with the manual annotation of the physicians. On average, our method has an accuracy of 0.9358, a recall of 0.9278, an IOU value of 0.8697, a Dice value of 0.9280, and an AUC value of 0.9632. The average error of the 3D model was within the allowable range of the surgery. The proposed algorithm can accurately segment bone tumors in pelvic MR images regardless of tumor location, size, and other factors. It provides the possibility to assist pelvic bone tumor preservation surgery.

A radiomics approach for predicting acute hematologic toxicity in patients with cervical or endometrial cancer undergoing external-beam radiotherapy.

PURPOSE: This study is purposed to establish a predictive model for acute severe hematologic toxicity (HT) during radiotherapy in patients with cervical or endometrial cancer and investigate whether the integration of clinical features and computed tomography (CT) radiomics features of the pelvic bone marrow (BM) could define a more precise model. METHODS: A total of 207 patients with cervical or endometrial cancer from three cohorts were retrospectively included in this study. Forty-one clinical variables and 2226 pelvic BM radiomic features that were extracted from planning CT scans were included in the model construction. Following feature selection, model training was performed on the clinical and radiomics features via machine learning, respectively. The radiomics score, which was the output of the final radiomics model, was integrated with the variables that were selected by the clinical model to construct a combined model. The performance of the models was evaluated using the area under the receiver operating characteristic curve (AUC). RESULTS: The best-performing prediction model comprised two clinical features (FIGO stage and cycles of postoperative chemotherapy) and radiomics score and achieved an AUC of 0.88 (95% CI, 0.81-0.93) in the training set, 0.80 (95% CI, 0.62-0.92) in the internal-test set and 0.85 (95% CI, 0.71-0.94) in the external-test dataset. CONCLUSION: The proposed model which incorporates radiomics signature and clinical factors outperforms the models based on clinical or radiomics features alone in terms of the AUC. The value of the pelvic BM radiomics in chemoradiotherapy-induced HT is worthy of further investigation.

Clinical study of acute toxicity of pelvic bone marrow-sparing intensity-modulated radiotherapy for cervical cancer.

OBJECTIVES: To compare the dose volume of the target area and the toxicity of pelvic bone marrow-sparing intensity-modulated radiotherapy (PBMS-IMRT) with routine IMRT in patients undergoing radiochemotherapy for cervical cancer. MATERIAL AND METHODS: Forty patients with indications for adjuvant radiochemotherapy after cervical cancer surgery were selected and randomly divided into IMRT (n = 20) and PBMS-IMRT (n = 20) groups to observe and record the toxicity and its severity in the blood, gastrointestinal tract, and genitourinary system. RESULTS: There was no significant difference in the target area conformity index (CI) or homogeneity index (HI) between the two groups (p > 0.05). The pelvic bone V10-V50 in the PBMS-IMRT group were lower than those in the IMRT group (p < 0.05), and there was lower hematological toxicity (p < 0.05) and fewer delays or interruptions in chemotherapy and/or radiotherapy (p < 0.05) in the PBMS-IMRT group. The toxicity to the gastrointestinal and genitourinary systems in the two groups was not significantly different (p > 0.05). CONCLUSIONS: PBMS-IMRT significantly reduced the dose volume of the pelvic bone marrow, thereby reducing the incidence of bone marrow suppression. However, it had no significant impact on the gastrointestinal or genitourinary systems.

Quantification and visualization of anterior pelvis bone density to optimize screw fixation: A novel technique.

Plate fixation of anterior pelvic ring fractures is often a vital component when surgically treating unstable pelvis fractures. Certain plate and screw configurations can have premature implant loosening, potentially in part due to insufficient pullout strength in lower density bone. This study sought to define densities about the anterior pelvic ring using a novel computer-based technique. Thirty-three patients who received a computed tomography (CT) of the abdomen/pelvis for reasons other than pelvis fracture in a 1-month time period were included. Three statistically distinct density regions of the anterior pelvis were identified based on the three-dimensional (3D) density map. The densest regions included both the anterior and posterior aspects of the superior pubic ramus, along with the region of bone along the inferior cotyloid fossa. The intermediate density region included the caudal and medial pubic body. The least dense region included the anterior aspect of the inferior pubic ramus (IPR), the posterior pubic body, and the posterior/inferior IPR. This study presents specific quantification of anterior pelvis bone density based on a novel technique using opportunistic CT scans. Clinical Significance: Anterior surgical fixation of unstable pelvic ring injuries may benefit from targeting areas of higher density as described in this novel technique.

Numerical Evaluations of an Uncemented Acetabular Component in Total Hip Arthroplasty: Effects of Loading and Interface Conditions.

Using finite element (FE) models of intact and implanted hemipelvises, the study aimed to investigate the influences of musculoskeletal loading and implant-bone interface conditions on preclinical analysis of an uncemented acetabular component after total hip arthroplasty (THA). A new musculoskeletal loading dataset, corresponding to daily activities of sitting up-down, stairs up-down and normal walking, for a pelvic bone was generated based on previously validated Gait2392 model. Three implant-bone interface conditions, fully bonded and debonded having two rim press-fits (1 mm and 2 mm), were analyzed. High tensile (2000-2415 µÏµ) and compressive strains (900-1035 µÏµ) were predicted for 2 mm press-fit, which might evoke microdamage in pelvic cortex. Strain shielding in periprosthetic cancellous bone was higher for bonded condition during sitting up activity, compared to other combinations of interface and loading conditions. Only the nodes around acetabular rim (less than 6%) were susceptible to interfacial debonding. Although maximum micromotion increased with increase in press-fit, postoperatively for all load cases, these were within a favorable range (52-143 µm) for bone ingrowth. Micromotions reduced (39-105 µm) with bone remodeling, indicating lesser chances of implant migration. Bone apposition was predominant around acetabular rim, compared to dome, for all interface conditions. Periprosthetic bone resorption of 10-20% and bone apposition of 10-15% were predicted for bonded condition. Whereas for press-fit (1 mm and 2 mm), predominant bone apposition of 200-300% was observed. This study highlights the importance of variations in loading and interface conditions on in silico evaluations of an uncemented acetabular component.

Interaction between Pelvic Bone Mineral Density and Sex Steroid Hormone on the Risk of Urinary Incontinence from National Health and Nutrition Examination Survey 2013-2014.

INTRODUCTION: The correlation between sex hormone levels and pelvic bone mineral density in people with urinary incontinence (UI) has not been evaluated. This study explored the association between sex hormones, pelvic bone mineral density, and UI, and analyzed the association between pelvic bone mineral density-combined sex hormones and UI in women. METHOD: The data of the National Health and Nutrition Examination Survey (NHANES) 2013-2014 were used in this cross-sectional study. Women aged 20 years and older with complete sex steroid hormone and pelvic bone mineral density data were included. Outcomes were stress UI (SUI), urgency UI (UUI), and mixed UI (MUI). Sex steroid hormone included testosterone, estradiol, and sex hormone binding globulin (SHBG). Multivariate logistic regression analyses with the odds ratios (ORs) and 95% confidence intervals (CIs) were used. RESULTS: Of 2,442 women, 579 had SUI, 202 had UUI, and 344 had MUI. The estimated multiplicative interactions were significantly between testosterone and pelvic bone mineral density, between SHBG and pelvic bone mineral density on UI (p = 0.002, p = 0.003), MUI (p = 0.036, p < 0.001), and SUI (p = 0.008, p = 0.044), respectively. High pelvic bone mineral density was associated with UI (p = 0.022) and MUI (p = 0.028) in the age <45-year-old subgroup. Multiplicative interactions were between testosterone and pelvic bone mineral density on all types of UI in the age <45-year-old subgroup, on SUI in women who did not have vaginal deliveries, and on UI in women who had more than one-time vaginal delivery. CONCLUSION: Our study found negatively multiplicative interactions between testosterone, SHBG, and pelvic bone mineral density on UI, MUI, and SUI. Similar results were found in women aged <45 years old and in women who had more than one-time vaginal delivery. Clinicians may consider testosterone or SHBG supplementation and pelvic density enhancement in women with SUI, MUI, and low endogenous testosterone levels.

Relationship between the pelvic bone marrow dose-volume parameters and acute hematologic toxicity in neoadjuvant pelvic intensity-modulated radiotherapy for local advance rectal cancer / 中华放射医学与防护杂志

Objective:To analyze the correlation between the volume of irradiated pelvic bone marrow and acute hematologic toxicity (HT), in order to provide clinical data to reduce the risk of acute HT and optimize the radiotherapy plan.Methods:From October 2017 to May 2019, 41 LARC patients who received neoadjuvant concurrent chemoradiotherapy (CCRT) were retrospectively reviewed in our center. All patients were treated with 5-field intensity-modulated radiotherapy (IMRT), and the prescription dose delivered to PTV was 45-50.4 Gy in 25-28 fractions. Capecitabine or 5-fluorouracil (5-FU) wasadministered daily 5 days a week during radiotherapy. Different HTswere recorded according to National Cancer Institute Common Toxicity Criteria Version 5.0 (NCI-CTC.V5.0) based on laboratory tests. The volume of PBM or each site (coxal, sacrum, femoral) receiving more than x Gy refers to as TVx, CVx, SVx, and FVx, respectively. Logistic regression was performed to evaluate the association between the volume of irradiated pelvic bone marrow and different HT. Generalized additive model (GAM) and piecewise regression were used to further analyze the possible nonlinear relationship and threshold effect between them. Results:Multivariate logistic regression analysis showed that low-dose of irradiated total pelvic bone marrow volume ( TV5) and coxal bone marrow volume ( CV5, CV10) were significantly correlated with Grade ≥2 leukopenia( P<0.05). There was a significant negative correlation between the sacrum bone marrow volume ( SV5, SV10) and Grade ≥2 leukopenia ( P<0.05). A thresholdeffect has been observed between CV10 and Grade ≥2 leukopenia by Generalized additive model (GAM) and piecewise linear regression. The threshold between CV10 and Grade ≥2 leukopenia was 575 ml, OR (95% CI) was 1.85 (1.08, 3.16). Conclusions:In neoadjuvant IMRT of rectal cancer, CV is a better predictor of acute HT induced by CCRT than TV. The irradiated volume of CV associated with acute HT was mainly low-dose levels ( CV5, CV10). The thresholds of our study ( CV10= 575 ml) could be a good reference for the optimization of the radiotherapy plan.

Internal Hemipelvectomy for primary bone sarcomas using intraoperative patient specific instruments- the next step in limb salvage concept.

BACKGROUND: During pelvic Sarcoma resections, Surgeons often struggle to obtain negative margins while minimizing collateral damage and maintaining limb function. These complications are usually due to the complex anatomy of the pelvis. Here we present an accurate 3D surgical approach, including pre-operative printing of models and intraoperative patient-specific instruments (PSIs) for optimizing pelvic sarcoma resections. METHODS: This single-center retrospective study (N = 11) presents surgical, functional, and oncological outcomes of patients (average age 14.6 +/- 7.6 years, 4 males) who underwent pelvic sarcoma resections using a 3D surgical approach between 2016 and 2021. All patients were followed up for at least 24 months (mean = 38.9 +/- 30.1 months). RESULTS: Our results show promising surgical, oncological, and functional outcomes. Using a 3D approach, 90.9% had negative margins, and 63.6% did not require reconstruction surgery. The average estimated blood loss was 895.45 ± 540.12 cc, and the average surgery time was 3:38 ± 0.05 hours. Our results revealed no long-term complications. Three patients suffered from short-term complications of superficial wound infections. At 24 month follow up 72.7% of patients displayed no evidence of disease. The average Musculoskeletal Tumor Society (MSTS) score at 12 months was 22.81. CONCLUSION: 3D technology enables improved accuracy in tumor resections, allowing for less invasive procedures and tailored reconstruction surgeries, potentially leading to better outcomes in function and morbidity. We believe that this approach will enhance treatments and ease prognosis for patients diagnosed with pelvic sarcoma and will become the standard of care in the future.

Digital chain for pelvic tumor resection with 3D-printed surgical cutting guides.

Surgical cutting guides are 3D-printed customized tools that help surgeons during complex surgeries. However, there does not seem to be any set methodology for designing these patient-specific instruments. Recent publications using pelvic surgical guides showed various designs with no clearly classified or standardized features. We, thus, developed a systematic digital chain for processing multimodal medical images (CT and MRI), designing customized surgical cutting guides, and manufacturing them using additive manufacturing. The aim of this study is to describe the steps in the conception of surgical cutting guides used in complex oncological bone tumor pelvic resection. We also analyzed the duration of the surgical cutting guide process and tested its ergonomics and usability with orthopedic surgeons using Sawbones models on simulated tumors. The original digital chain made possible a repeatable design of customized tools in short times. Preliminary testing on synthetic bones showed satisfactory results in terms of design usability. The four artificial tumors (Enneking I, Enneking II, Enneking III, and Enneking I+IV) were successfully resected from the Sawbones model using this digital chain with satisfactory ergonomic outcomes. This work validates a new digital chain conception and production of surgical cutting guides. Further works with quantitative margin assessments on anatomical subjects are needed to better assess the design implications of patient-specific surgical cutting guide instruments in pelvic tumor resections.