Accuracy of pelvic bone segmentation for 3d printing: a study of segmentation accuracy based on anatomic landmarks to evaluate the influence of the observer.

BACKGROUND: 3D printing has a wide range of applications and has brought significant change to many medical fields. However, ensuring quality assurance (QA) is essential for patient safety and requires a QA program that encompasses the entire production process. This process begins with imaging and continues on with segmentation, which is the conversion of Digital Imaging and Communications in Medicine (DICOM) data into virtual 3D-models. Since segmentation is highly influenced by manual intervention the influence of the users background on segmentation accuracy should be thoroughly investigated. METHODS: Seventeen computed tomography (CT) scans of the pelvis with physiological bony structures were identified, anonymized, exported as DICOM data sets, and pelvic bones were segmented by four observers with different backgrounds. Landmarks were measured on DICOM images and in the segmentations. Intraclass correlation coefficients (ICCs) were calculated to assess inter-observer agreement, and the trueness of the segmentation results was analyzed by comparing the DICOM landmark measurements with the measurements of the segmentation results. The correlation between segmentation trueness and segmentation time was analyzed. RESULTS: The lower limits of the 95% confidence intervals of the ICCs for the seven landmarks analyzed ranged from 0.511 to 0.986. The distance between the iliac crests showed the highest agreement between observers, while the distance between the ischial tuberosities showed the lowest. The distance between the upper edge of the symphysis and the promontory showed the lowest deviation between DICOM measurements and segmentation measurements (mean deviations < 1 mm), while the intertuberous distance showed the highest deviation (mean deviations 14.5-18.2 mm). CONCLUSIONS: Investigators with diverse backgrounds in segmentation and varying experience with slice images achieved pelvic bone segmentations with landmark measurements of mostly high agreement in a setup with high realism. In contrast, high variability was observed in the segmentation of the coccyx. In general, interobserver agreement was high, but due to measurement inaccuracies, landmark-based approaches cannot conclusively show that segmentation accuracy is within a clinically tolerable range of 2 mm for the pelvis. If the segmentation is performed by a very inexperienced user, the result should be reviewed critically by the clinician in charge.

Comparison of mortality between open and closed pelvic bone fractures in Korea using 1:2 propensity score matching: a single-center retrospective study.

Purpose: Open pelvic bone fractures are relatively rare and are considered more severe than closed fractures. This study aimed to compare the clinical outcomes of open and closed severe pelvic bone fractures. Methods: Patients with severe pelvic bone fractures (pelvic Abbreviated Injury Scale score, ≥4) admitted at a single level I trauma center between 2016 and 2020 were retrospectively analyzed. Patients aged <16 years and those with incomplete medical records were excluded from the study. The patients were divided into open and closed fracture groups, and their demographics, treatment, and clinical outcomes were compared before and after 1:2 propensity score matching. Results: Of the 321 patients, 24 were in the open fracture group and 297 were in the closed fracture group. The open fracture group had more infections (37.5% vs. 5.7%, P<0.001) and longer stays in the intensive care unit (median 11 days, interquartile range [IQR] 6-30 days vs. median 5 days, IQR 2-13 days; P=0.005), but mortality did not show a statistically significant difference (20.8% vs. 15.5%, P=0.559) before matching. After 1:2 propensity score matching, the infection rate was significantly higher in the open fracture group (37.5% vs. 6.3%, P=0.002), whereas the length of intensive care unit stay (median 11 days, IQR 6-30 days vs. median 8 days, IQR 4-19 days; P=0.312) and mortality (20.8% vs. 27.1%, P=0.564) were not significantly different. Conclusions: The open pelvic fracture group had more infections than the closed pelvic fracture group, but mortality was not significantly different. Aggressive treatment of pelvic bone fractures is important regardless of the fracture type, and efforts to reduce infection are important in open pelvic bone fractures.

Shaping the skeleton: impact of GnRH analogue and sex hormone therapy on skeletal dimensions in transgender individuals.

CONTEXT: Skeletal dimensions vary between sexes. Men typically have broader shoulders and women a wider pelvis. If gender affirming hormone therapy (GAHT) with or without prior puberty suppression (PS) alters these dimensions in transgender individuals remains unclear. OBJECTIVE: To investigate impact of PS and GAHT on skeletal dimensions. DESIGN: Retrospective cross-sectional study. SETTING: Gender identity clinic. PARTICIPANTS: Transgender individuals assigned male at birth (AMAB) and assigned female at birth (AFAB) who underwent dual-energy X-ray absorptiometry (DXA) scanning between ages 18 and 28 years were divided into four groups: Early PS (Tanner G/B2-3)+GAHT, Late PS (Tanner G/B4-5)+GAHT, GAHT only, and Untreated. MAIN OUTCOME MEASURES: Shoulder and pelvis dimensions measured by DXA scan were compared between groups, with adjustment for height. RESULTS: A total of 121 individuals AMAB and 122 AFAB were included. Only in individuals AMAB who underwent early PS had smaller shoulders compared to untreated individuals AMAB (-1.3 cm; 95%CI -2.1; -0.5). In individuals AMAB from both the early and late PS group, pelvic inlet, pubic symphysis width and interischial distance were greater compared to untreated individuals AMAB resulting in dimensions comparable to untreated individuals AFAB. Only in early PS AFAB pelvic inlet width was smaller compared to untreated individuals AFAB (-1.0 cm; 95%CI -1.5; -0.6), and comparable to untreated individuals AMAB. CONCLUSIONS: The study results suggest that skeletal dimensions are only altered by GAHT if endogenous puberty has not yet been completed at start of PS. These findings enhance our understanding of hormonal effects on the skeleton and may hold clinical relevance for body image as well as for forensic anthropology. Future research should evaluate clinical implications for surgical or obstetrical outcomes in transgender individuals.

Clinical outcomes of pelvic bone marrow sparing radiotherapy for cervical cancer: A systematic review and meta-analysis of randomised controlled trials.

Background: Concurrent chemoradiotherapy (CRT) is the standard treatment for locally advanced cervical cancer. We investigated how additional bone marrow sparing (BMS) affects the clinical outcomes. Methods: We queried MEDLINE, Embase, Web of Science Core Collection, Google Scholar, Sinomed, CNKI, and Wanfang databases for articles published in English or Chinese between 2010/01/01 and 2023/10/31. Full-text manuscripts of prospective, randomised trials on BMS in cervical cancer patients treated with definitive or postoperative CRT were included. Risk of bias (RoB) was assessed using Cochrane Collaboration's RoB tool. Random-effects models were used for the meta-analysis. Results: A total of 17 trials encompassing 1297 patients were included. The majority were single-centre trials (n = 1268) performed in China (n = 1128). Most trials used CT-based anatomical BMS (n = 1076). There was a comparable representation of trials in the definitive (n = 655) and postoperative (n = 582) settings, and the remaining trials included both.Twelve studies reported data on G ≥ 3 (n = 782) and G ≥ 2 (n = 754) haematologic adverse events. Both G ≥ 3 (OR 0.39; 95 % CI 0.28-0.55; p < 0.001) and G ≥ 2 (OR 0.29; 95 % CI 0.18-0.46; p < 0.001) toxicity were significantly lowered, favouring BMS. Seven studies (n = 635) reported data on chemotherapy interruptions, defined as receiving less than five cycles of cisplatin, which were significantly less frequent in patients treated with BMS (OR 0.44; 95 % CI 0.24-0.81; p = 0.016). There was no evidence of increased gastrointestinal or genitourinary toxicity.There were no signs of significant heterogeneity. Four studies were assessed as high RoB; sensitivity analyses excluding these provided comparable results for main outcomes. The main limitations include heterogeneity in BMS methodology between studies, low representation of populations most affected by cervical cancer, and insufficient data to assess survival outcomes. Conclusions: The addition of BMS to definitive CRT in cervical cancer patients decreases hematologic toxicity and the frequency of interruptions in concurrent chemotherapy. However, data are insufficient to verify the impact on survival and disease control.

Comparison of Conventional versus Modified Preperitoneal Pelvic Packing in Patients with Bleeding Pelvic Fractures: A Single-Center Retrospective Pilot Study.

Background: Bleeding pelvic fractures have high mortality rates, primarily due to severe hemorrhage. Treatment options include mechanical stabilization based on preperitoneal pelvic packing (PPP), resuscitative endovascular balloon occlusion of the aorta, and angioembolization (AE). The bilateral preperitoneal approach, which uses three pads on each side, is the conventional PPP method. We aimed to compare the bilateral preperitoneal approach with a modified approach, involving selectively packing only heavily bleeding areas, in terms of clinical outcomes and mortality risks. Methods: We included patients who underwent PPP and compared the outcomes between conventional (three sponges placed on each side) and modified PPP (selective packing of critical areas). The primary outcome was 30-day mortality; the secondary outcomes included 24 h mortality, pelvic complications, and transfusion requirements. Univariate and multivariate analyses were performed to determine risk factors for 30-day and 24 h mortality. Results: Among the 47 included patients, 19 and 28 underwent conventional and modified PPP, respectively. There were no significant between-group differences in the 24 h (26.3% vs. 42.9%, p = 0.247) and 30-day mortality rates (47.4% vs. 60.7%, p = 0.366). Using univariate and multivariate analyses, initial lactate levels and the decision to perform AE were found to be significant risk factors for mortality. However, the selected PPP method was not a risk factor for 30-day mortality (odds ratio [OR], 2.22; 95% confidence interval [CI], 0.27-18.26; p = 0.457) or 24 hr mortality (OR, 1.77; 95% CI, 0.24-13.19; p = 0.557). Conclusions: The modified PPP method may be considered in patients with bleeding pelvic fractures for effective bleeding control while minimizing potential complications associated with the conventional PPP.

Trends and current aspects of reconstructive surgery for gynecological cancers.

Gynecologic cancers can lead to gynecologic tract destruction with extension into both the gastrointestinal and urinary tracts. Recurrent disease can also affect the surrounding bony pelvis and pelvic musculature. As opposed to advanced ovarian cancer, where cytoreduction is the goal, in these scenarios, an oncologic approach to achieve negative margins is critical for benefit. Surgeries aimed at achieving a R0 resection in gynecologic oncology can have a significant impact on pelvic anatomy, and require reconstruction. Overall, it appears that these types of radical surgery are less frequently performed; however, when required, multidisciplinary teams at high-volume centers can potentially improve short-term morbidity. There are few data to examine the long-term, quality-of-life outcomes after reconstruction following oncologic resection in advanced and recurrent gynecologic cancers. In this review we outline considerations and approaches for reconstruction after surgery for gynecologic cancers. We also discuss areas of innovation, including minimally invasive surgery and the use of 3D surgical anatomy models for improved surgical planning.In the era of 'less is more', pelvic exenteration in gynecologic oncology is still indicated when there are no other curative-intent alternatives in persistent or recurrent gynecological malignancies confined to the pelvis or with otherwise unmanageable symptoms from fistula or radiation necrosis. Pelvic exenteration is one of the most destructive procedures performed on an elective basis, which inevitably carries a significant psychologic, sexual, physical, and emotional burden for the patient and caregivers. Such complex ultraradical surgery, which requires removal of the vagina, vulva, urinary tract, and/or gastrointestinal tract, subsequently needs creative and complex reconstructive procedures. The additional removal of sidewall or perineal structures, like pelvic floor muscles/vulva, or portions of the musculoskeletal pelvis, and the inclusion of intra-operative radiation further complicates reconstruction. This review paper will focus on the reconstruction aspects following pelvic exenteration, including options for urinary tract restoration, reconstruction of the vulva and vagina, as well as how to fill large empty spaces in the pelvis. While the predominant gastrointestinal outcome after exenteration in gynecologic oncology is an end colostomy, we also present some novel new options for gastrointestinal tract reconstruction at the end.

Quantitative Volumetric Measurements of Bone Grafting Sites Within the Lower Extremity on Computed Tomography Scans.

The anterior iliac crest is one of the most used options; however, pain and other complications have been reported. Other options for bone harvest in the lower extremity, such as the proximal tibia and calcaneus, can be useful sites for bone grafting. Computed tomography angiography images of the lower extremity were analyzed using 3-D Slicer™ medical imaging software, creating an advanced 3-dimensional model. Bone volume (cm3) and bone mineral density (Hounsfield units) were measured from the cancellous bone in the anterior iliac crest, posterior iliac crest, proximal tibia, and the calcaneus. Fifteen studies were included. The total volume measured it was of 61.88 ± 14.15 cm3, 19.35 ± 4.16 cm3, 32.48 ± 7.49 cm3, 26.40 ± 7.18 cm3, for the proximal tibia, anterior and posterior iliac crest, and calcaneus, respectively. Regarding Hounsfield units, the densities were 116 ± 58.77, 232.4 ± 68.65, 214.4 ± 74.45, 170.5 ± 52.32, for proximal tibia, anterior and posterior iliac crest, and calcaneus. The intraclass correlation coefficients were in average >0.94. In conclusion, the proximal tibia has more cancellous bone than the anterior and posterior iliac crest. The calcaneus has more cancellous bone than the anterior iliac crest. Bone mineral density was highest in the anterior iliac crest and in proximal tibia was the lowest value.

External iliac artery thrombosis as a result of acetabular fixation through the ilioinguinal approach: a case report.

Introduction and importance: Acetabular fractures mostly occur in young people who are involved in high-energy trauma and they are treated by orthopedic trauma surgeons. Patients with acetabular fractures are at high risk for different kinds of complications. We report a case of postoperative thrombosis of the external iliac artery following fixation surgery performed by an ilioinguinal approach while receiving thromboprophylaxis during admission to the hospital. Case presentation: A 57-year-old healthy woman presented with a left both-column acetabular fracture and underwent acetabular fixation through the ilioinguinal approach. The patient was receiving antithrombotic prophylaxis medications in the course of treatment. Clinical discussion: During her convalescence, while at the hospital, she was diagnosed with left external iliac artery thrombosis, needing surgical thrombectomy. These severe and rare complications will lead to uncertainty about a commonly used ilioinguinal approach. Postoperative arterial thrombosis may be rare in patients undergoing acetabular fixation surgery but searching for signs and symptoms of this condition is always necessary. Conclusion: It is possible to prevent severe complications by performing a routine measurement of the distal arterial pressure after similar surgeries.

Does primary tumor resection improve survival for patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at diagnosis ?

BACKGROUND: Recent studies demonstrated that primary tumor resection (PTR) improves survival of patients with metastatic bone sarcomas. However, it remains quite unclear regarding the role of PTR in the treatment of sarcomas of pelvic bones with synchronous metastasis at diagnosis. METHODS: Using the Surveillance, Epidemiology, and End Results Program, we enrolled a total of 385 patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at initial diagnosis, including 139 patients with osteosarcoma, 176 with Ewing sarcoma, and 70 with chondrosarcoma. Association between PTR and disease-specific survival (DSS) were investigated using the univariable and multivariable Cox regression models. Hazard ratio (HR) and 95% confidence interval (CI) were reported. Representative institutional PTR strategies and clinical outcomes for patients with metastatic pelvic sarcomas from our cancer center were displayed. RESULTS: The usage rate of PTR was 28.1% (39/139) in osteosarcoma, 13.6% (24/176) in Ewing sarcoma, and 41.4% (29/70) in chondrosarcoma with synchronous metastatic lesions. PTR was not associated with an improved DSS for metastatic pelvic osteosarcoma (HR = 0.686, 95% CI = 0.430 ~ 1.094, P = 0.113) and Ewing sarcoma (HR = 0.580, 95% CI = 0.291 ~ 1.154, P = 0.121). The use of PTR was associated with an improved DSS for metastatic pelvic chondrosarcoma (HR = 0.464, 95% CI = 0.225 ~ 0.954, P = 0.037). CONCLUSION: Primary lesion resection may provide a survival benefit for metastatic chondrosarcoma, but not for osteosarcoma and Ewing sarcoma of pelvic bones, sacrum, and coccyx. This population-based study recommends an active surgical intervention for metastatic chondrosarcoma while non-surgical treatment for metastatic osteosarcoma and Ewing sarcoma of the pelvis in terms of survival improvement.

THE RELATIONSHIP BETWEEN FRACTURES IN PEDIATRIC POLYTRAUMA PATIENTS: EVALUATION OF CLINICAL OUTCOMES.

Objective: To evaluate children and adolescents with polytrauma and fractures of the pelvis and proximal and diaphyseal femur and correlate the impact of these conditions and clinical outcomes. Methods: Retrospective study carried out in a public hospital in Taboão da Serra (SP), with pediatric patients with polytrauma from January 2012 to December 2021. In total, 44 patients were evaluated, 70.44% boys and 29.55% girls, aged from 12 to 17 years. Results: Diaphyseal fracture of the femur affected 70.44% of the patients, mainly caused by a fall from a height (56.81%). Linear external fixation was the most used treatment (45.45%). All patients were discharged from hospital. Conclusion: We found essential sociodemographic information: 84.11% of patients did not have associated injuries; 88.63% were hospitalized from 3 to 11 days; 90.91% did not need to be admitted to an ICU, 77.27% did not need reoperation, and 22.73% underwent another surgery; 45.45% used the external fixator to stabilize injuries; 11.36% converted the external fixator to the intramedullary nail; 9.09% needed an intramedullary nail remover; 2.27% converted to a plate (bilateral) and 2.27% to a rigid nail; 2.27% had loss of reduction and revision with rod; 2.27% underwent corrective osteotomy; 2.27% had clinical hospitalization; 2.27% had osteonecrosis of the femoral head and screws removed; 2.27% removed the plate. No deaths were recorded. Level of Evidence II, Retrospective Study.

Objetivo: Avaliar crianças e adolescentes politraumatizados com fraturas da pelve, proximal e diafisária do fêmur e correlacionar o impacto dessas condições e desfechos clínicos. Métodos: Estudo retrospectivo realizado em hospital público de Taboão da Serra (SP), com pacientes pediátricos politraumatizados entre janeiro de 2012 e dezembro de 2021. Avaliaram-se 44 pacientes, 70,44% meninos e 29,55% meninas, de 12 a 17 anos. Resultados: A fratura diafisária fechada do fêmur acometeu 70,44%, sendo causada principalmente por queda de altura (56,81%). A fixação externa linear foi o tratamento mais utilizado (45,45%). Todos os pacientes receberam alta hospitalar. Conclusão: Identificaram-se importantes informações sociodemográficas: 84,11% dos pacientes não apresentaram lesões associadas; 88,63% ficaram internados de 3 a 11 dias; 90,91% não necessitaram de internação em unidade de terapia intensiva (UTI), 77,27% não precisaram ser reoperados; 22,73% realizaram nova cirurgia; 45,45% utilizaram fixador externo para estabilização de lesões;11,36% converteram o fixador externo para a haste intramedular; 9,09% precisaram remover as hastes intramedulares; 2,27% converteram para placa (bilateral) e 2,27% para haste rígida; 2,27% tiveram perda de redução e revisão com haste; 2,27% realizaram osteotomia corretiva; 2,27% tiveram internação clínica; 2,27% tiveram osteonecrose da cabeça femoral e parafusos removidos; e 2,27% retiraram a placa. Não foram observados óbitos. Nível de Evidência II, Estudo Retrospectivo.

Investigating the correlation between hip abductor muscle strength and width in anteroposterior pelvic radiographs in hip revision candidates following previous total hip arthroplasty: a cross-sectional study.

The changes in strength of hip abductor muscles after total hip arthroplasty may depend on its anatomical parameters. In the present study the correlation between the strength of the hip abductor muscles before hip revision surgery and the diameter of the abductor muscles in the pelvic anterior posterior X-ray was investigated. Methods: This cross-sectional study included the patients underwent hip arthroplasty and were candidates for revision surgery. The diameter of the hip abductor muscles on the affected and unaffected sides were calculated based on plain radiography. Patients were also clinically examined and their abductor muscle strength on both sides were determined based on Medical Research Council Manual Muscle Testing scale. Results: A total of 51 patients were included in the study and after exiting 20 patients; finally 31 patients' data were analyzed. Based on results there was a significant correlation between the ratios of muscle strength and muscle diameter in affected side to unaffected side (r=0.517, P=0.003). As indicated in Table 3, such significant association was revealed in men (r=0.719, P=0.001), but not in women (r=-0.092, P=0.754). Also, this relationship was found to be significant in patients older than 60 years (r=0.529, P=0.011), not in the younger. Conclusion: In patients undergoing total hip arthroplasty revision surgery, there is a strong association between the ratio of strength and diameter of the abductor muscles in the affected side to the unaffected side especially in men and older ages.

Early experience with resuscitative endovascular balloon occlusion of the aorta for unstable pelvic fractures in the Republic of Korea: a multi-institutional study.

PURPOSE: Recently, trauma centers in the Republic of Korea introduced resuscitative endovascular balloon occlusion of the aorta (REBOA) for application in severe pelvic fracture cases. This study aimed to determine the efficacy of REBOA and its associated factors in enhancing survival. METHODS: Data from patients with severe pelvic injuries at two regional trauma centers from 2016 to 2020 were retrospectively reviewed. Patients were dichotomized into REBOA and no-REBOA groups, and patient characteristics and clinical outcomes were compared using 1:1 propensity score matching. Additional survival-based analysis was performed in the REBOA group. RESULTS: REBOA was performed in 42 of the 174 patients with pelvic fractures. As patients in the REBOA group had more severe injuries than did patients in the no-REBOA group, 1:1 propensity score matching was performed to adjust for severity. After matching, 24 patients were included in each group and mortality was not significantly different (REBOA 62.5% vs. no-REBOA 41.7%, P = 0.149). Kaplan-Meier analysis revealed no significant differences in mortality between the two matched groups (log-rank test, P = 0.408). Among the 42 patients treated with REBOA, 14 survived. Shorter REBOA duration (63 [40-93] vs. 166 [67-193] min, P = 0.015) and higher systolic blood pressure before REBOA (65 [58-76] vs. 54 [49-69] mmHg, P = 0.035) were associated with better survival. CONCLUSIONS: The effectiveness of REBOA has not been definitively established; however, it was not associated with increased mortality in this study. Additional studies are required to better understand how REBOA can be effectively used for treatment.

Comparison of Anterior Iliac Crest Versus Proximal Tibia Autologous Bone Graft Harvesting: A Systematic Review and Meta-Analysis.

Anterior iliac crest (AIC) is the preferred option for bone grafting; however, pain and complications are reported. Proximal tibia (PT) is a sourceful site for bone grafting with lower complications. MEDLINE, EMBASE, and Scopus were searched to identify studies comparing AIC and PT autograft procedure. The main outcome was pain and complication rate. As well as cadaveric and cell-based studies were analyzed for quantity and quality of AIC and PT autograft. A meta-analysis was performed using the generic inverse variance method with random or fixed effects model depending on heterogeneity between studies. Heterogeneity was tested with the I2 statistic index. Fifteen studies were included in the meta-analysis. Six studies and 248 patients were included for clinical outcomes. A significant pain reduction favoring PT at 24 hours was detected after meta-analysis and corresponding sensitivity analysis. The estimated effect size ranged from -2.31 to -2.93 cm, with confidence intervals aligned to the left indicating a robust steady decrease in pain across studies. This effect was not observed after 1 month. A total of 18 complications were reported, 13 in the AIC group and 5 in the PT group. Four cadaveric studies were included, 3 favored PT on the quantity of bone graft harvested. Five cell-based studies were included, only one study favored AIC for quality of bone graft. Our study concludes that PT bone harvest is a reliable option for bone grafting regarding morbidity, complications, volume graft obtained, and cellular and molecular properties. However, the current evidence is still insufficient to draw definitive conclusions, especially in terms of bone healing. PROSPERO Register: CRD42020198150.

Initial experience, feasibility, and technical development with an electromagnetic navigation assistance in percutaneous pelvic bone cementoplasty: retrospective analysis.

OBJECTIVES: To assess the feasibility and technical outcomes of pelvic bone cementoplasty using an electromagnetic navigation system (EMNS) in standard practice. MATERIALS AND METHODS: Monocentric retrospective study of all consecutive patients treated with cementoplasty or reinforced cementoplasty of the pelvic bone with EMNS-assisted procedures. The endpoints were periprocedural adverse events, needle repositioning rates, procedure duration, and radiation exposure. RESULTS: A detailed description of the technical steps is provided. Thirty-three patients (68 years ± 10) were treated between February 2016 and February 2020. Needle repositioning was required for 1/33 patients (3%). The main minor technical adverse event was soft tissue PMMA cement leaks. No major adverse event was noted. The median number of CT acquisitions throughout the procedures was 4 (range: 2 to 8). Radiation exposure and mean procedure duration are provided. CONCLUSION: Electromagnetic navigation system-assisted percutaneous interventions for the pelvic bone are feasible and lead to low rates of minor technical adverse events and needle repositioning. Procedure duration and radiation exposure were low. KEY POINTS: • Initial experience for 33 patients treated with an electromagnetic navigation assistance for pelvic cementoplasty shows feasibility and safety. • The use of an electromagnetic navigation system does not expose to high procedure duration or radiation exposure. • The system is efficient in assisting the radiologist for extra-axial planes in challenging approaches.

The lateral stress radiograph: an effective alternative to examination under anesthesia for identifying occult instability in minimally displaced lateral compression pelvic ring injuries.

PURPOSE: The purpose of this study was to review the practice of utilizing lateral stress radiographs (LSRs) to identify occult instability (≥ 10 mm of dynamic displacement on LSRs) of minimally displaced lateral compression type 1 (LC1) pelvic ring injuries and to evaluate for associations between instability and patient demographics, injury characteristics, and hospital course. METHODS: A retrospective review of a prospective registry from 2018 to 2022 identified 151 patients with LC1 injuries. LSRs were obtained in 86.8% (131/151) of patients. Three (2.2%) patients were excluded for malrotation of LSRs, leaving 128 patients for analysis. RESULTS: The median maximum dynamic displacement on LSRs was 12.2 mm (IQR: 5.9 to 17.3). Occult instability was present in 62.5% (80/128) of patients and was associated with older age (Median difference 11.0 years, 95% CI 3.0 to 20.0), Nakatani type 1 rami fractures (73.7% vs. 47.9%, p = 0.001), and rami fracture comminution (Proportional difference 58.7%, 95% CI 42.8 to 71.3%), but not gender, high-energy mechanism, bilateral rami fractures, Denis classification, sacral fracture completeness, or sacral comminution. Patients with occult instability took longer to ambulate 15 feet and clear physical therapy (PT), were more likely to be unable to clear PT by hospital day 3 or by time of discharge, had longer hospital stays, and were more likely to require rehabilitation facilities. CONCLUSION: LSRs were obtained in a majority of patients. Occult instability was frequently present and associated with older age, comminuted distal pubic rami fractures, longer hospital stays, longer times to mobilize and clear PT, and an increased need for rehabilitation facilities.

Digital pair-matching of iliac bones: pilot study on a three-dimensional approach with models acquired through stereophotogrammetry.

Three-dimensional (3D) pair-matching has brought about an innovative approach for the analysis of commingled skeletal remains, and it has been tested on bone models acquired through CT and laser scans. Here, 3D models of 40 innominate bones (20 left and 20 right) of 20 documented male individuals from a cemeterial skeletal collection were acquired through a stereophotogrammetric device (VECTRA M3, Canfield Scientific, Inc.). The ventral iliac surface was chosen as the anatomical region of interest (ROI) for the analysis. Each left ROI was mirrored and superimposed on the matching right ROI (contralateral element from the same individual) and mismatching ROIs (contralateral elements from different individuals). The point-to-point distance between models was calculated through the Vectra Analysis Module (VAM) software and the root mean square (RMS) point-to-point distance value was used to evaluate the sorting performance of the method, in terms of sensitivity and specificity rates. Differences in RMS between matches and mismatches were investigated through a Student's t test (p < 0.05). The state of preservation of the remains was assessed following an index of anatomical completeness and differences in RMS distances of true matches according to different anatomical completeness were assessed through the Mann-Whitney test (p < 0.05). RMS point-to-point distances of matches and mismatches were significantly different (p < 0.01), being the matches lower than mismatches. The RMS threshold of 2.9 mm identified all the true pairs; the test was 100% sensitive and 51% specific. The RMS of matches with a better state of preservation are significantly lower than the less preserved matches (p < 0.05). In general, a low RMS distance value may indicate a true match, being it to be further verified. The 3D approach for sorting innominate bones provides a valid screening test that could complete subjective and osteometric methods with numerical evidence of the match. Preliminary data suggest a possible relation between RMS distance values and taphonomic condition, which would benefit from further research.

Hematopoietic Stem Cell Identification Postirradiation.

Radiation exposure is particularly damaging to cells of the hematopoietic system, inducing pancytopenia and bone marrow failure. The study of these processes, as well as the development of treatments to prevent hematopoietic damage or enhance recovery after radiation exposure, often require analysis of bone marrow cells early after irradiation. While flow cytometry methods are well characterized for identification and analysis of bone marrow populations in the nonirradiated setting, multiple complications arise when dealing with irradiated tissues. Among these complications is a radiation-induced loss of c-Kit, a central marker for conventional gating of primitive hematopoietic populations in mice. These include hematopoietic stem cells (HSCs), which are central to blood reconstitution and life-long bone marrow function, and are important targets of analysis in these studies. This chapter outlines techniques for HSC identification and analysis from mouse bone marrow postirradiation.

Spontaneous recanalization of complete urethral injury treated by suprapubic cystostomy alone after severe pelvic bone fracture in a young male patient in Korea: a case report.

Injury to the genitourinary tract is rare, with an incidence of less than 1%. Younger men (mean age, approximately 30 years) are predominantly affected. We introduce an unusual case of a 25-year-old male patient with complete urethral injury combined with a severe open pelvic bone fracture. During the emergency surgery, the primary realignment of the posterior urethra could not be performed due to a large defect. With suprapubic cystostomy alone, follow-up voiding cystourethrography showed spontaneous recanalization of the transected urethra after four months. Suprapubic cystostomy is an efficient treatment option when primary realignment is not possible.

A method of bedside urethrography before catheterization in pelvic trauma in Korea: a case report.

We introduce a convenient method of urethrography before catheterization for patients with pelvic trauma that can be used in a resuscitation area. A 10-mL syringe without a needle was used. X-ray contrast medium (Iohexol, 300 mg I/mL) was administered through the urethral orifice using a 10-mL syringe without needle and a simple pelvic anteroposterior film was taken (70 kilovolt [peak], 50 mAs). A 36-year-old soldier with a saddle injury from a gun barrel was taken to a trauma center. He had a pelvic fracture and complained of hematuria. Bedside urethrography above described was performed. The anterior urethra showed nonspecific findings, but dye leaked from the posterior urethra. Bedside Foley catheter insertion was attempted, but the catheter could not be advanced past the membranous urethra. Thereafter, suprapubic catheterization was performed. On the day of the injury, iliac artery embolization was carried out. The dislocated sacroiliac joint was also treated using open reduction and internal fixation. On hospital day 7, guidewire Foley insertion was performed. This bedside urethrography technique is simple and useful for pelvic fractures in which urethral injury is suspected.