Incidence and clinical features of endometriosis in 2484 consecutive female patients undergoing appendectomy for suspected appendicitis-a retrospective analysis.

INTRODUCTION: Endometriosis is a common condition affecting 5 to 10% of women of childbearing age. The true incidence of endometriosis of the appendix is currently unknown. Since symptoms often overlap with those of acute appendicitis, endometriosis of the appendix presents a diagnostic challenge in the emergency department. This large retrospective study investigates the incidence and perioperative clinical, radiologic, and laboratory findings, as well as possible differences between patients with and without endometriosis. METHODS: Data from consecutive patients who underwent appendectomy for suspected appendicitis without a history of endometriosis were analyzed. Perioperative clinical, laboratory, perioperative, and histopathologic findings were compared between women with and without endometriosis. RESULTS: Between January 2008 and June 2023, 2484 consecutive patients without a history of endometriosis underwent urgent appendectomy for suspected appendicitis. Endometriosis was detected on histopathologic examination in 17 (0.7%) patients. Signs of appendicitis were found less frequently on ultrasound in the endometriosis group compared to the non-endometriosis group (23.4% vs. 61.5%; p = 0.002; OR = 0.193; 95% CI 0.063-0.593). There were no differences in physical examination findings, duration of symptoms, degree of inflammation, surgical outcomes, or complication rates. CONCLUSION: The incidence of endometriosis of the appendix in patients undergoing appendectomy for suspected appendicitis was higher than suggested by data from autopsy series and populations with biopsy-proven endometriosis. Patients with endometriosis of the appendix were less likely to have a positive ultrasound finding, but perioperative and histopathologic findings and severity of inflammation did not differ from patients without endometriosis, presenting diagnostic challenges for clinicians.

Terahertz electric-field-driven dynamical multiferroicity in SrTiO3.

The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the dynamical control and creation of novel ordered states of matter not accessible in thermodynamic equilibrium is receiving much attention1-6. The theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of magnetization due to time-dependent electric polarization in non-ferromagnetic materials7,8. In simple terms, the coherent rotating motion of the ions in a crystal induces a magnetic moment along the axis of rotation. Here we provide experimental evidence of room-temperature magnetization in the archetypal paraelectric perovskite SrTiO3 due to this mechanism. We resonantly drive the infrared-active soft phonon mode with an intense circularly polarized terahertz electric field and detect the time-resolved magneto-optical Kerr effect. A simple model, which includes two coupled nonlinear oscillators whose forces and couplings are derived with ab initio calculations using self-consistent phonon theory at a finite temperature9, reproduces qualitatively our experimental observations. A quantitatively correct magnitude was obtained for the effect by also considering the phonon analogue of the reciprocal of the Einstein-de Haas effect, which is also called the Barnett effect, in which the total angular momentum from the phonon order is transferred to the electronic one. Our findings show a new path for the control of magnetism, for example, for ultrafast magnetic switches, by coherently controlling the lattice vibrations with light.

Genetic association between the APOE ε4 allele, toxicant exposures and Gulf war illness diagnosis.

INTRODUCTION: Exposure to nerve agents, pyridostigmine bromide (PB), pesticides, and oil-well fires during the 1991 Gulf War (GW) are major contributors to the etiology of Gulf War Illness (GWI). Since the apolipoprotein E (APOE) ε4 allele is associated with the risk of cognitive decline with age, particularly in the presence of environmental exposures, and cognitive impairment is one of the most common symptoms experienced by veterans with GWI, we examined whether the ε4 allele was associated with GWI. METHODS: Using a case-control design, we obtained data on APOE genotypes, demographics, and self-reported GW exposures and symptoms that were deposited in the Boston Biorepository and Integrative Network (BBRAIN) for veterans diagnosed with GWI (n = 220) and healthy GW control veterans (n = 131). Diagnosis of GWI was performed using the Kansas and/or Center for Disease Control (CDC) criteria. RESULTS: Age- and sex-adjusted analyses showed a significantly higher odds ratio for meeting the GWI case criteria in the presence of the ε4 allele (Odds ratio [OR] = 1.84, 95% confidence interval [CI = 1.07-3.15], p ≤ 0.05) and with two copies of the ε4 allele (OR = 1.99, 95% CI [1.23-3.21], p ≤ 0.01). Combined exposure to pesticides and PB pills (OR = 4.10 [2.12-7.91], p ≤ 0.05) as well as chemical alarms and PB pills (OR = 3.30 [1.56-6.97] p ≤ 0.05) during the war were also associated with a higher odds ratio for meeting GWI case criteria. There was also an interaction between the ε4 allele and exposure to oil well fires (OR = 2.46, 95% CI [1.07-5.62], p ≤ 0.05) among those who met the GWI case criteria. CONCLUSION: These findings suggest that the presence of the ε4 allele was associated with meeting the GWI case criteria. Gulf War veterans who reported exposure to oil well fires and have an ε4 allele were more likely to meet GWI case criteria. Long-term surveillance of veterans with GWI, particularly those with oil well fire exposure, is required to better assess the future risk of cognitive decline among this vulnerable population.

Effectiveness, safety and quality-of-life effects of guselkumab and ustekinumab in patients with psoriasis: Week 104 results from the non-interventional, prospective, German multicentre PERSIST study.

BACKGROUND: PERSIST was a prospective, non-interventional, real-world study of guselkumab and ustekinumab in adult patients with moderate-to-severe plaque psoriasis in Germany. OBJECTIVES: To examine effectiveness, safety and quality-of-life (QoL) outcomes to Week (W) 104 of treatment with guselkumab and ustekinumab in patients with moderate-to-severe plaque psoriasis. METHODS: Patients (≥18 years of age) received guselkumab or ustekinumab as per routine clinical practice. Outcomes to W104 were examined separately in guselkumab and ustekinumab recipients. An ad hoc exploratory analysis of outcomes with guselkumab versus ustekinumab was also performed following propensity score matching. RESULTS: Overall, 302 and 313 patients received guselkumab and ustekinumab, respectively. Patients in both cohorts experienced improvements in disease activity and QoL that were maintained to W104, with 64.7% and 63.6% of guselkumab- and 54.6% and 64.4% of ustekinumab-treated patients achieving a Psoriasis Area and Severity Index (PASI) 90 response and a Dermatology Life Quality Index (DLQI) 0/1 score, respectively. Propensity score matching yielded well-balanced baseline characteristics except for prior biologic use, which was higher in guselkumab versus ustekinumab recipients (51.7% vs. 32.0%). Achievement of PASI ≤1 at W104 was more common in guselkumab versus ustekinumab recipients (58.7% vs. 49.7%). The W104 PASI90 response rate was 65.6% with guselkumab and 56.0% with ustekinumab; corresponding rates for PASI100 were 44.3% and 28.5%. In guselkumab recipients, response rates were higher in biologic-naïve versus biologic-experienced patients (PASI90, 77.1% vs. 53.4%; PASI100, 55.0% vs. 33.0%). A high level of response for QoL outcomes was observed for both treatments. CONCLUSIONS: Ustekinumab and guselkumab led to improvements in physician-assessed and patient-reported outcomes that were sustained for up to 2 years, with no new safety signals identified. Following propensity score matching, greater improvements in PASI outcomes were observed with guselkumab versus ustekinumab. Improvements with guselkumab were highest in biologic-naïve patients, highlighting the value of early treatment.

Rehybridization dynamics into the pericyclic minimum of an electrocyclic reaction imaged in real-time.

Electrocyclic reactions are characterized by the concerted formation and cleavage of both σ and π bonds through a cyclic structure. This structure is known as a pericyclic transition state for thermal reactions and a pericyclic minimum in the excited state for photochemical reactions. However, the structure of the pericyclic geometry has yet to be observed experimentally. We use a combination of ultrafast electron diffraction and excited state wavepacket simulations to image structural dynamics through the pericyclic minimum of a photochemical electrocyclic ring-opening reaction in the molecule α-terpinene. The structural motion into the pericyclic minimum is dominated by rehybridization of two carbon atoms, which is required for the transformation from two to three conjugated π bonds. The σ bond dissociation largely happens after internal conversion from the pericyclic minimum to the electronic ground state. These findings may be transferrable to electrocyclic reactions in general.

Horse-related injury patterns: a single center report.

BACKGROUND: For ages, humankind and horses have been closely related to occupational and recreational activities. The dangers of engaging with horses have been previously reported. Among sporting activities, horse riding is well-known for its risks. Despite multiple recommendations to wear protective gear, horse-related activities still comprise the risk of severe injuries. This study aimed to examine: (1) if specific mechanisms are correlated to particular injury patterns and (2) if injury types are related to patient demographics. METHODS: From one level I trauma center, between July 2019 and July 2022 (3 years) all emergency reports and discharge letters were retrospectively reviewed by full-text search regarding horse-related injuries. Patient demographics, body mass index, trauma mechanism, injury types, and initiated treatment were extracted from medical records and analyzed. RESULTS: During the study period, 95 patients with 99 horse-related injuries were included. The overwhelming majority of the patients was female (93.7%). Age averaged 35.3 years (range 6 to 71). BMI was 23.6 kg/m2. Inpatient treatment was required in 60.6%. Length of hospital stay averaged 10 days. Surgical treatment was performed in 55 patients (55.6%). Open reduction and internal fixation was the most common procedure (74.5%). Trauma mechanism was fall from a horse followed by being hit by a horse (60.6% and 23.2%, respectively). Injured upper extremities counted up for 52.5% followed by spinal and pelvic injuries (23.2%). Spinal and pelvic injuries were related to fall from a horse (p < 0.001). Injuries to the lower extremities were predominantly caused by a kick of the horse when the rider was unmounted (p = 0.001) and negatively related to a fall from a horse (p = 0.002). Ten patients got their fingers tangled while holding the reins and suffered from injuries to the upper extremity (p < 0.001). Three of them required an amputation (30%). CONCLUSION: Despite the fact that patients are young and healthy, horse related injuries must not be underestimated. In our study, almost two-thirds of the patients required inpatient treatment and 50% underwent surgery. We could show that patient age was related to injury severity according to the Abbreviated Injury Scale (AIS). Spinal and pelvic injuries were significantly related to a fall from a horse with a significantly greater trauma impact according to the AIS. Therefore, these severe entities need to be ruled out in such events. Accidents caused by holding the reins, may result in serious injuries to the hand with 30% requiring an amputation. Doctors need to be aware of possible horse-related injury patterns to reduce morbidity.

Preoperative joint line convergence angle correction is a key factor in optimising accuracy in varus knee correction osteotomy.

PURPOSE: This study aimed to identify and prevent preoperative factors that can be influenced in preoperative planning to reduce postoperative malcorrections. METHODS: The method used in this study was a retrospective two-centre analysis of 78 pre and postoperative fully weight-bearing radiographs of patients who underwent valgus osteotomy correction due to symptomatic medial compartment osteoarthritis. A computer software (TraumaCad®) was used to aim for an intersection point of the mechanical tibiofemoral axis (mTFA) with the tibia plateau at 55-60% (medial = 0%, lateral = 100%). Postoperative divergence ± 5% of this point was defined as over- and undercorrection. Preoperative joint geometry factors were correlated with postoperative malcorrection. Planning was conducted using the established method described by Miniaci (Group A) and with additional correction of the joint line convergence angle (JLCA) using the formula JLCA-2/2 (Group B). Additionally, in a small clinical case series, planning was conducted with JLCA correction. Statistical analysis was performed using (multiple) linear regression analysis and analysis of variance (ANOVA) with p < 0.05 considered significant. RESULTS: In 78 analysed cases, postoperative malcorrection was detected in 37.2% (5.1% undercorrection, 32.1% overcorrection). Linear regression analysis revealed preoperative body mass index (BMI, p = 0.04), JLCA (p = 0.0001), and osteotomy level divergence (p = 0.0005) as factors correlated with overcorrection. In a multiple regression analysis, JLCA and osteotomy level divergence remained significant factors. Preoperative JLCA correction reduced the planned osteotomy gap (A 9.7 ± 2.8 mm vs B 8.3 ± 2.4 mm; p > 0.05) and postoperative medial proximal tibial angle (MPTA: A 94.3 ± 2.1° vs B 92.3 ± 1.5°; p < .05) in patients with preoperative JLCA ≥ 4°. The results were validated using a virtual postoperative correction of cases with overcorrection. A case series (n = 8) with a preoperative JLCA > 4 revealed a postoperative accuracy using the JLCA correction of 3.4 ± 1.9%. CONCLUSION: Preoperative JLCA ≥ 4° and tibial osteotomy level divergence were identified as risk factors for postoperative overcorrection. Preoperative JLCA correction using the formula JLCA-2/2 is proposed to better control ideal postoperative correction and reduce MPTA. The intraoperatively realised osteotomy level should be precisely in accordance with preoperative planning. LEVEL OF EVIDENCE: III, cross-sectional study.

Noise-resilient edge modes on a chain of superconducting qubits.

Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model, which exhibits nonlocal Majorana edge modes (MEMs) with [Formula: see text] parity symmetry. We find that any multiqubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.

Pulmonary embolism in menopausal hormone therapy: a population-based register study.

OBJECTIVE: Oral but not transdermal menopausal hormone therapy (MHT) increases the risk of venous thromboembolism. There is no evidence regarding the risk of the serious complication pulmonary embolism (PE). The aim was to investigate the risk of PE in women using MHT depending on administration route, type of progestin and treatment duration. METHOD: The population-based case-control study covered 1,771,253 women aged 40-69 years, during 2006-2015. Diagnoses of PE (n = 13,974) and drug dispensations were received from national validated registers. RESULTS: Current MHT users had a higher risk of PE than non-users (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.05-1.26). First ever users had the highest risk (OR 2.07, 95% CI 1.23-3.50). Transdermal administration was not associated with increased risk of PE. The OR was slightly but non-significantly higher with estrogen combined with medroxyprogesterone acetate than with norethisterone acetate. DISCUSSION: The risk of PE was significantly increased in users of oral but not transdermal MHT, with the highest risk in first ever users of oral estrogen combined with medroxyprogesterone acetate. The risk was considerably lower in women with recurrent treatment, probably because of the healthy user effect. CONCLUSION: PE was most common close to initiation of oral treatment. Transdermal MHT did not increase the risk of PE.

Real-world evidence from the non-interventional, prospective, German multicentre PERSIST study of patients with psoriasis after 1 year of treatment with guselkumab.

BACKGROUND: PERSIST was a prospective, non-interventional, long-term, German multicentre study of patients with moderate-to-severe psoriasis receiving guselkumab, an approved monoclonal antibody that binds to the p19 subunit of interleukin (IL)-23, in a real-world setting. OBJECTIVES: Evaluation of the efficacy and safety of guselkumab, and its effect on health-related quality of life (HRQoL), in patients with moderate-to-severe psoriasis who have received 52 weeks of treatment. METHODS: Patients (≥18 years old) were prescribed guselkumab as per routine clinical practice. End points assessed include Psoriasis Area and Severity Index (PASI), Physician's Global Assessment (PGA), target Nail Psoriasis Severity Index (NAPSI), and the Dermatology Life Quality Index (DLQI). RESULTS: Overall, 303 patients were enrolled and treated with guselkumab. Mean disease duration was 21.0 years, and 77.2% and 51.2% of patients had received ≥1 prior conventional systemic or ≥1 prior biologic therapy, respectively. Mean PASI score decreased from 16.4 at baseline to 3.0 by Week (W) 28, and further decreased to 2.4 by W52, while the proportion of patients achieving an absolute PASI score of ≤1 increased from 1.3% at baseline, to 50.8% at W28 and to 58.4% by W52. PASI90 and PASI100 responses also showed marked improvements between W28 and W52, regardless of biologic treatment history. Clearance of psoriatic skin was observed in difficult-to-treat areas, with the percentage of patients achieving a PGA score ≤1 increasing between W28 and W52. Guselkumab improved HRQoL; mean DLQI score decreased from 13.7 at baseline to 2.8 by W28, and further decreased to 2.4 by W52. At W52, 64.6% of patients achieved a DLQI score ≤1. The cumulative probability of drug survival was 92.4% at W52. CONCLUSIONS: Guselkumab is efficacious and well tolerated regardless of previous biologic therapies, comorbidities or psoriasis manifestation in difficult-to-treat areas. No new safety signals were observed.

Observation of photo-induced plasmon-phonon coupling in PbTe via ultrafast x-ray scattering.

We report the observation of photo-induced plasmon-phonon coupled modes in the group IV-VI semiconductor PbTe using ultrafast x-ray diffuse scattering at the Linac Coherent Light Source. We measure the near-zone-center excited-state dispersion of the heavily screened longitudinal optical (LO) phonon branch as extracted from differential changes in x-ray diffuse scattering intensity following above bandgap photoexcitation. We suggest that upon photoexcitation, the LO phonon-plasmon coupled (LOPC) modes themselves become coupled to longitudinal acoustic modes that drive electron band shifts via acoustic deformation potentials and possibly to low-energy single-particle excitations within the plasma and that these couplings give rise to displacement-correlations that oscillate in time with a period given effectively by the heavily screened LOPC frequency.

Brine residues and organics in the Urvara basin on Ceres.

Ceres is a partially differentiated dwarf planet, as confirmed by NASA's Dawn mission. The Urvara basin (diameter ~170 km) is its third-largest impact feature, enabling insights into the cerean crust. Urvara's geology and mineralogy suggest a potential brine layer at the crust-mantle transition. Here we report new findings that help in understanding the structure and composition of the cerean crust. These results were derived by using the highest-resolution Framing Camera images acquired by Dawn at Ceres. Unexpectedly, we found meter-scale concentrated exposures of bright material (salts) along the crater's upper central ridge, which originate from an enormous depth, possibly from a deep-seated brine or salt reservoir. An extended resurfacing modified the southern floor ~100 Myr after crater formation (~250 Myr), long after the dissipation of the impact-generated heat. In this resurfaced area, one floor scarp shows a granular flow pattern of bright material, showing spectra consistent with the presence of organic material, the first such finding on Ceres beyond the vast Ernutet area. Our results strengthen the hypothesis that Ceres is and has been a geologically active world even in recent epochs, with salts and organic-rich material playing a major role in its evolution.

Understanding why consumers in China switch between wild, farmed and synthetic bear bile products.

An important rationale for legally-farmed and synthetic wildlife products are that they reduce illegal wild-sourced trade by supplying markets with sustainable alternatives. For this to work, more established illegal-product consumers must switch to legal alternatives than new legal-product consumers drawn to illegal wild products. Despite widespread debate on the magnitude and direction of switching, studies among actual consumers are lacking. We used an anonymous online survey of 1421 Traditional Chinese Medicine consumers in China to investigate switching between legal farmed, synthetic, and illegal wild bear bile. We examined past consumption behaviour, and applied a discrete choice experiment framed within worsening hypothetical disease scenarios, using latent class models to investigate groups with shared preferences. Bear bile consumers (86% respondents) were wealthier, more likely to have family who consumed bile, and less knowledgeable about bile treatments than non-consumers. Consumer preferences were heterogenous but most consumers preferred switching between bile types as disease worsened. We identified five distinct latent classes within our sample: 'law-abiding consumers' (34% respondents), who prefer legal products and were unlikely to switch; two 'all-natural consumer' groups (53%), who dislike synthetics but may switch between farmed and wild products; and two 'non-consumer' groups (12%) who prefer not to buy bile. People with past experience of bile consumption had different preferences than those without. Willingness to switch to wild products was related to believing they were legal, although the likelihood of switching was mediated by preferences for cheaper products sold in legal, familiar places. We show that consumers of wild bile may switch, given the availability of a range of legal alternatives, while legal-product consumers may switch to illegal products if the barriers to doing so are small. Understanding preferences that promote or impede switching should be a key consideration when attempting to predict consumer behaviour in complex wildlife markets. This article is protected by copyright. All rights reserved.

Wildlife consumer characteristics and preferences determine their likelihood and direction of switching between legal and illegal products.

KDM6A mutations promote acute cytoplasmic DNA release, DNA damage response and mitosis defects.

BACKGROUND: KDM6A, encoding a histone demethylase, is one of the top ten mutated epigenetic cancer genes. The effect of mutations on its structure and function are however poorly characterized. METHODS: Database search identified nonsense and missense mutations in the N-terminal TPR motifs and the C-terminal, catalytic JmjC domain, but also in the intrinsically disordered region connecting both these two well-structured domains. KDM6A variants with cancer-derived mutations were generated using site directed mutagenesis and fused to eGFP serving as an all-in-one affinity and fluorescence tag to study demethylase activity by an ELISA-based assay in vitro, apoptosis by FACS, complex assembly by Co-immunoprecipitation and localization by microscopy in urothelial cells and apoptosis by FACS. RESULTS: Independent of the mutation and demethylase activity, all KDM6A variants were detectable in the nucleus. Truncated KDM6A variants displayed changes in complex assemblies affecting (1) known interactions with the COMPASS complex component RBBP5 and (2) KDM6A-DNA associated assemblies with the nuclear protein Nucleophosmin. Some KDM6A variants induced a severe cellular phenotype characterized by multiple acute effects on nuclear integrity, namely, release of nuclear DNA into the cytoplasm, increased level of DNA damage indicators RAD51 and p-γH2A.X, and mitosis defects. These damaging effects were correlated with increased cell death. CONCLUSION: These observations reveal novel effects of pathogenic variants pointing at new specific functions of KDM6A variants. The underlying mechanisms and affected pathways have to be investigated in future research to understand how tumor cells cope with and benefit from KDM6A truncations.

[Acute pancreatitis : Typical findings in computed tomography and magnetic resonance imaging]. / Akute Pankreatitis : Typische Befunde in Computer- und Magnetresonanztomographie.

CLINICAL PROBLEM: Imaging plays a major role to differentiate interstitial edematous from necrotic pancreatitis and to describe relevant local complications for proper patient management and decision-making in acute pancreatitis. STANDARD RADIOLOGICAL PROCEDURES: The revised Atlanta classification 2012 of acute pancreatitis divides patients into mild, moderately severe and severe groups. Computed tomography (CT) and magnetic resonance imaging (MRI) are well established for diagnosis and follow-up of acute pancreatitis and its complications METHODOLOGICAL INNOVATIONS AND ASSESSMENT: Based on the revised Atlanta classification, CT and MRI allow for adequate categorization of interstitial edematous and necrotic pancreatitis. Imaging and standardized reporting nomenclature enable confident differentiation of early and late complications in acute pancreatitis. RECOMMENDATIONS: The aim of this review article is to present an image-rich overview of different morphologic characteristics of acute pancreatitis and associated local complications by CT or MRI using case examples.

Topological Magnetic Materials of the (MnSb2Te4)·(Sb2Te3)n van der Waals Compounds Family.

Using density functional theory, we propose the (MnSb2Te4)·(Sb2Te3)n family of stoichiometric van der Waals compounds that harbor multiple topologically nontrivial magnetic phases. In the ground state, the first three members of the family (n = 0, 1, 2) are 3D antiferromagnetic topological insulators, while for n ≥ 3 a special phase is formed, in which a nontrivial topological order coexists with a partial magnetic disorder in the system of the decoupled 2D ferromagnets, whose magnetizations point randomly along the third direction. Furthermore, due to a weak interlayer exchange coupling, these materials can be field-driven into the FM Weyl semimetal (n = 0) or FM axion insulator states (n ≥ 1). Finally, in two dimensions, we reveal these systems to show intrinsic quantum anomalous Hall and AFM axion insulator states, as well as quantum Hall state, achieved under external magnetic field. Our results demonstrate that MnSb2Te4 is not topologically trivial as was previously believed that opens possibilities of realization of a wealth of topologically nontrivial states in the (MnSb2Te4)·(Sb2Te3)n family.

Asymmetry in the propagation of vortex domain wall artificial skyrmion composite system.

We studied the propagation of an artificial skyrmion coupled to the vortex domain wall (VDW). We discovered the following effect: depending on the propagation's direction, the dynamics of the coupled skyrmion VDW can be faster than the isolated VDW's velocity. The reason for such behavior is the structural distortion that occurs in the coupled system. We interpret the numerical results in terms of the modified Thiele's equation. In particular, increasing the Thiele's equation counteractive coefficient leads to the perfect fitting with the micromagnetic simulation results.

Navigated iliac screw placement may reduce radiation and OR time in lumbopelvic fixation of unstable complex sacral fractures.

PURPOSE: Instability of the posterior pelvic ring may be stabilized by lumbopelvic fixation. The optimal osseous corridor for iliac screw placement from the posterior superior iliac spine to the anterior inferior iliac spine requires multiple ap- and lateral-views with additional obturator-outlet and -inlet views. The purpose of this study was to determine if navigated iliac screw placement for lumbopelvic fixation influences surgical time, fluoroscopy time, radiation exposure, and complication rates. METHODS: Bilateral lumbopelvic fixation was performed in 63 patients. Implants were inserted as previously described by Schildhauer. A passive optoelectronic navigation system with surface matching on L4 was utilized for navigated iliac screw placement. To compare groups, demographics were assessed. Operative time, fluoroscopic time, and radiation were delineated. RESULTS: Conventional fluoroscopic imaging for lumbopelvic fixation was performed in 32 patients and 31 patients underwent the procedure with navigated iliac screw placement. No differences were found between the groups regarding demographics, comorbidities, or additional surgical procedures. Utilization of navigation led to fluoroscopy time reduction of more than 50% (3.2 vs. 8.6 min.; p < 0.001) resulting in reduced radiation (2004.5 vs. 5130.8 Gy*cm2; p < 0.001). Operative time was reduced in the navigation group (176.7 vs. 227.4 min; p = 0.002) despite the necessity of additional surface referencing. CONCLUSION: For iliac screws, identifying the correct entry point and angle of implantation requires detailed anatomic knowledge and multiple radiographic views. In our study, additional navigation reduced operative time and fluoroscopy time resulting in a significant reduction of radiation exposure for patients and OR personnel.