The acceptor removal process is the most detrimental effect encountered in irradiated boron-doped silicon. This process is caused by a radiation-induced boron-containing donor (BCD) defect with bistable properties that are reflected in the electrical measurements performed in usual ambient laboratory conditions. In this work, the electronic properties of the BCD defect in its two different configurations (A and B) and the kinetics behind transformations are determined from the variations in the capacitance-voltage characteristics in the 243–308 K temperature range. The changes in the depletion voltage are consistent with the variations in the BCD defect concentration in the A configuration, as measured with the thermally stimulated current technique. The A→B transformation takes place in non-equilibrium conditions when free carriers in excess are injected into the device. B→A reverse transformation occurs when the non-equilibrium free carriers are removed. Energy barriers of 0.36 eV and 0.94 eV are determined for the A→B and B→A configurational transformations, respectively. The determined transformation rates indicate that the defect conversions are accompanied by electron capture for the A→B conversion and by electron emission for the B→A transformation. A configuration coordinate diagram of the BCD defect transformations is proposed. These sensors were designed to withstand an integrated luminosity of 300 fb−1 corresponding to a cumulated radiation level of 2 × 1015 neq/cm2  and ionizing doses of about 300 kGy. Common to n-type silicon sensors is the type inversion, a phenomenon occurring gradually with an increasing irradiation fluence . In all the TSC measurements, the samples were cooled to T0 = 10 K where filling of the BCD defects was achieved by a forward current injection of 350 µA. Then, the samples were reverse biased and heated with a constant rate of β = 11 K/min. The applied reverse bias (RV) during heating was large enough to ensure the full depletion of the samples over the entire TSC temperature scan. In such a case, the TSC signal generated by a density of tN homogeneously distributed electron traps is given by  value can be associated with the variations in effN determined from C-V characteristics at 293 K. The large difference between the magnitude of the TSC peaks in PAD and LGAD diodes is due to the charge multiplication effect in the gain layer of LGAD structures, which amplifies the electrons signal. Thus, the TSC signals associated with the emission of electrons is multiplicated, the amplification factor being above 10 for all the detected electron traps, which is in agreement with the gain measured by Lange et al. on similar LGAD samples [Considering that there is a 2 h delay between the 5.7 µA injection at 293 K and the recording of the first TSC spectrum, during which the BCD defect can partly switch back in the A configuration, the determined Δ[ samples . ABCD0/+ donor level has unstable behavior and can be associated with the variations in effN at an ambient temperature. Thus, during the small forward current injection at 293 K, the BCD switches from A to B configuration, losing its donor character and causing an increase in depV  ground state. Presuming that the increase in ΔeffN is caused entirely by the decrease in ABCD(0/+) concentration via first-order kinetics, the ΔeffN(t) = effN(t) − effN0 can be described by:The change from A to B configuration of the BCD defect can be well investigated following the effect on k for A to B defect conversion can be determined by performing similar experiments and evaluations at different temperatures. The results obtained in the 243 K–303 K temperature range are given in the Arrhenius plot depicted in A→BE = 0.363 eV is determined for the energy needed to convert the BCD defect from A to B configuration. The pre-exponential factor for this transformation (k0A→B) is in the order of 103 s−1 and it is much smaller than the value predicted for a free-carrier capture, an aspect that will be discussed in The temperature dependence of the transformation rates effN  diagram based on the energy barriers determined in our study. The CC diagram is depicted in A+BCD charge state has to first capture an electron and then to surmount the energy barrier A→BE = 0.363 eV  donor state was determined to be located at t,E0 = 0.286 eV from the conduction band of silicon. In non-equilibrium conditions, the defect can capture a free electron at ambient temperatures, overpassing the energy barrier of A→BE = 0.363 eV needed for changing into the neutral-charged B configuration (BBCD0). The defect remains in this BBCD0 state as long as electrons in excess exist in the sample. Removing the source of non-equilibrium carriers, the defect returns back in its donor configuration ABCD(0/+) by emitting an electron which surmounts the B→AE = 0.94 eV large barrier. Although the present study does not elucidate the microscopic atomic structure of the BCD defects, it reveals the physical mechanisms behind the conversions between two defect configurations and the consequences these transformations have on the electrical characteristics of the device. The experiments performed in this work allow us to reveal the kinetics behind the BCD defect configurational transformations and to determine the electronic properties of two structural configurations, A and B. Thus, in equilibrium conditions, the BCD defect is found in the A configuration. From TSC investigations, the corresponding zero-field energy level for the


These results suggest that 2% milled BRT can improve safety and palatability while maximizing the retention of flavor compounds and nutrients. The findings of this study contribute to an enhanced understanding of the dynamics of changes and preservation of aroma compounds and nutrients present during the processing of BRT.This study investigated the effects of rice preparation using different degrees of milling (DOM) from 0% to 13% on the nutritional composition, functional properties, major volatile compounds and safety of brown rice tea (BRT). We found that 2% DOM reduced 52.33% of acrylamide and 31.88% of fluorescent AGEs. When DOM was increased from 0% to 13%, the total phenolic content (TPC) of brown rice tea decreased by 48.12%, and the total flavonoid content (TFC) and condensed tannin content (CTC) also decreased significantly, with the smallest decrease at 2% DOM. In addition, the inhibitory activities of α-amylase, α-glucosidase and pancreatic lipase as well as the antioxidant activity also decreased gradually. Analysis by electronic nose and gas chromatography-mass spectrometry (GC-MS) showed that alkanes, furans, aldehydes, pyrazines and alcohols were the major volatiles in BRT, with 2% DOM having the greatest retention of aroma compounds. An orthogonal partial least squares discriminant analysis (OPLS-DA) and VIP score (VIP > 1 and  AmonFurthermore, different DOMs can significantly affect the volatile compounds of rice due to the different concentrations of volatile compounds produced during the milling process . PreviouTaking into account above factors, the security, physicochemical properties, phenolic compounds content and functional characteristics of BRT with different DOMs were investigated. Additionally, the effect of milling on BRT aroma compounds was analyzed by using a combination of electronic nose and GC–MS. Finally, the OPLS-DA model was used to gain insight into the correlation between the aroma volatility spectrum and the DOM. The conclusions will help to optimize the grinding conditions for BRT processing and provide a scientific basis for balancing the flavor quality and nutritional composition of BRT during the grinding process.2.2.1.Rice of the indica cultivar Juliangyou-60 was supplied by the Food Crops Institute, Hubei Academy of Agricultural Sciences . The brown rice was milled for 0 s, 1 s, 3 s, 6 s, 9 s and 12 s using the SXJMJ-858 rice milling machine . Six different DOMs of rice  were obtained by the ratio of the weight of milled rice bran to the weight of unmilled brown rice. DOM is calculated according to 2.2.The atmospheric pressure drying method was used to determine the moisture content. AACC method 08–01 and method 86–80 were used to determine the content of ash, protein, lipid, and dietary fiber (DF) . The con2.3.Acrylamide was analyzed in triplicate according to the method of Champrasert et al. , with slFluorescent AGEs were obtained using a method described by Wang et al. , with sl2.4.The extraction of bound and free polyphenols from BRT was made according to the method described by Li et al. . Based o2.5.2.5.1.The method for the DPPH assay was adapted from Fukui et al. . Brieflywhere, Ac = Absorbance of control at 517 nm, As = Absorbance of the sample at 517 nm.2.5.2.Zhang et al.  reported2.5.3.The method for the OH assay was adapted from Yongxu et al. . Brieflywhere, Ac = Absorbance of control at 624 nm, As = Absorbance of the sample at 624 nm.2.6.2.6.1.α-amylase inhibition assay was analyzed according to the method of Fatemeh et al.  of the volatile components was conducted according to Yi et al. . Briefly2.9.The sensory evaluation of rice tea was referenced from Hyun-Jin et al.  with sli2.10.All data are averages obtained after repeating the experiment three times. Statistical analysis and graphical production of the data were performed by SPSS 26.0, Origin 2021, SIMCA-P version 14.1; and others the software was completed.3.3.1.p < 0.05). With the DOM of BRT increasing, the L* value increased, the a* and b* value decreased. These changes resulted in a decrease in the browning index (BI) of the BRT samples, indicating that grinding minimizes the browning of the samples. Similar patterns have been described for baked brown rice and roasted chickpeas . A large proportion of the polyphenolic substances in the BRTs were in the free state, accounting for 67.2–84.76% of the TPC. 0% DOM had the greatest content of free and total phenols with 198.05 and 256.55 mg GAE/100 g. A 5% increase in DOM was observed, the TPC in BRT decreased slightly and then decreased substantially thereafter, in agreement with previous studies on the TPC of different bran fractions of black rice  were stronger than those of other samples , indicating that retention of whole rice bran significantly (p < 0.05) enhanced the α-amylase and α-glucosidase inhibitory activities  when DOM increased from 0 to 2%, and remained relatively stable thereafter. According to previous studies that brown rice is rich in ferulic acid, coumaric acid and apigenin, all of which have good inhibitory effects on the activities of alpha-amylase, alpha-glucosidase and pancreatic lipase  contained a total of 67 volatile compounds classified into 17 groups including 14 aldehydes, 13 pyrazines, 5 furans, 5 pyrroles, 5 alcohols, 6 alkanes, 3 ketones, 3 alkenes, 2 esters, 2 ethers, 1 phenol, 1 benzene, 1 amine and 3 thiophenes. The results in As shown in In the second group of volatiles, some of the aroma contributors of rice were ground off, like 2-ethyl-5-methylpyrazine, 3-ethyl-2,5-dimethylpyrazine, 3,5-diethyl-2-methylpyrazine, furfural, 5-methyl-2-furancarboxaldehyde, 1-(2-furanylmethyl)-1H-pyrrole, 1-octanol, (e)-2-nonenal, 6-methyl-2-heptanone, and styrene, resulting in a significant reduction in the aroma intensity of BRT. The reduction in the content of these aromas could be attributed to the removal of a large amount of non-enzymatic browning reaction substrates with the milling process . Therefo3.6.p < 0.05).We analyzed the changes of the grinding process on the volatile compounds of BRT by building an OPLS-DA model. OPLS-DA uses orthogonal signal correction to select signals that are strongly associated with the model classification, better separating samples between groups and making the explanatory power clearer and more credible . As show3.7.p < 0.05). With the DOM of BRT increasing, the overall acceptance of tea infusions decreased, the mouthfeel score of rice grains decreased. This is because 0% DOM BRT contains the most dietary fiber, resulting in greater hardness and poorer taste of rice grains -2-nonenal, -2,4-nonadienal and 2-ethoxy-ethanol. This study provides significant data to guide the appropriate processing and aroma quality of BRT.The original contributions presented in the study are included in the article/LZ: methodology, investigation, and writing. YS: investigation and funding acquisition. ZZ: investigation. SL: funding acquisition and writing – original draft. RX: writing – original draft. JW: investigation and visualization. JS: investigation. SC and TX: supervision and resources. FC: supervision, funding acquisition, and resources. XM: conceptualization, supervision, funding acquisition, and writing – review & editing. All authors contributed to the article and approved the submitted version.This work was supported by the project of Special Project for Science and Technology Innovation of Wuhan (2022020801020344). Science and Technology Plan Project of Hubei Province (2023BBB101). The support of the National Key Research and Development Program of China (2018YFD0301306-4-2), Outstanding young and middle-aged science and technology innovation team in Hubei Province (T2020012), the Science and Technology Plan Project in Agriculture and Rural Areas of Hubei Province in 2023 were also appreciated.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


To investigate the safety and accuracy of applying a new self-guided pedicle tap to assist pedicle screw placement.A new self-guided pedicle tap was developed based on the anatomical and biomechanical characteristics of the pedicle. Eight adult spine specimens, four males and four females, were selected and tapped on the left and right sides of each pair of T1-L5 segments using conventional taps (control group) and new self-guided pedicle taps , respectively, and pedicle screws were inserted. The screw placement time of the two groups were recorded and compared using a stopwatch. The safety and accuracy of screw placement were observed by CT scanning of the spine specimens and their imaging results were graded according to the Heary grading criteria.P > 0. 05). The Heary grading of pedicle screws showed 112 (82.35%) Heary grade I screws and 126 (92.65%) Heary grade I + II screws in the experimental group, while 96 (70.59%) Heary grade I screws and 112 (82.35%) Heary grade I + II screws in the control group.The difference between the two groups was statistically significant (P < 0.05).Screw placement time of the experimental group were (5. 73 ± 1. 18) min in thoracic vertebrae and (5. 09 ± 1. 31) min in lumbar vertebrae respectively. Screw placement time of the control group were respectively (6. 02 ± 1. 54) min in thoracic vertebrae and (5.51 ± 1.42) min in lumbar vertebrae. The difference between the two groups was not statistically significant (The new self-guided pedicle tap can safely and accurately place thoracic and lumbar pedicle screws with low-cost and convenient procedure,which indicates a good clinical application value. As a symbol of the rapid development of modern spine surgery, the pedicle screw internal fixation technique has been widely used in various spinal disorders, such as trauma, deformity, tumor, and degenerative diseases. In recent years, many scholars have begun to study the use of neurophysiological monitoring, computer navigation and 3D printed guides to achieve accurate placement of pedicle screws, however, which were not widely used in primary hospitals, because of the expensive equipments, prolonged operation time and training of professionals –3. At prP > 0.05) , four males and four females, excluding trauma, congenital developmental malformations, and scoliosis deformities, were provided by the Department of Anatomy and Research, Xuzhou Medical University. The posterior median incision was taken in the thoracolumbar spine, and the skin, subcutaneous tissue, and lumbar dorsal fascia were incised. The paravertebral muscles were peeled away to expose the vertebral plates, articular processes, and transverse processes. The same spine surgeon placed all pedicle screws in eight spine specimens from T1to L5 on the right and left side of the pedicle, and randomly selected one side of the pedicle to be tapped with a self-guided tap  and the other side to be tapped with a conventional tap (control group), in order to compare the indicators related to pedicle screw placement on both sides. The anatomical features including minimum diameter and length of the pedicle channel were observed by radiological measurement, and the difference between the two groups was not statistically significant Table .Table 1CThe self-guided tap was made of medical stainless steel and consists of a threaded end, elastic structure and handle end Fig. . The tipThe method of Fennell  was chosA stopwatch was used to record the time of each screw placement, starting from the removal of the cortical opening at the pedicle entry site and ending when the screw was completely screwed in. The thoracolumbar specimens were scanned with a CT machine  after screw placement. The pedicle screw placement was evaluated by Heary grading criteria: Grade I, entirely contained within pedicle; Grade II, violates lateral pedicle but screw tip entirely contained within the vertebral body (VB); Grade III, tip penetrates anterior or lateral VB; Grade IV, breaches medial or inferior pedicle; Grade V, violates pedicle or VB and endangers spinal cord, nerve root, or great vessels and requires immediate revision [s), and independent samples t-test was used for comparison between two groups. Qualitative data were compared using theχ2 analyses, and differences were considered statistically significant (P < 0. 05).SPSS software was used for statistical analysis, and quantitative data were expressed as mean ± standard deviation respectively in both groups.There were no statistically significant differences in screw placement time between the two groups in the thoracic and lumbar segments Table . No addiThe results of CT scans after pedicle screw placement were shown in Figs. The main difficulties of thoracic pedicle screw placement are as follows: (1) the transverse diameter of the thoracic pedicle is significantly narrow, especially in the upper and middle thoracic segments. The average width of the pedicles in the T4-T8 segments is smaller than 5 mm, so the screws could easily penetrate the pedicle cortex when improperly placed . Helm etDegenerative diseases of the lumbar spine tend to be more common than the thoracic spine because of the extra stress and mobility. Lumbar spinal stenosis, spondylolisthesis, and degenerative scoliosis often lead to vertebrae rotation, pedicle deformity, and hyperplasia of the facet joints, which could influence the lumbar pedicle screw placement. Therefore, the technique of pedicle screw placement remains an urgent challenge for spine surgery.The key to free-hand technique are the identification of the entry site and the direction of the screw, which determine the final screw placement. Therefore, enough surgical experience and correct subjective judgment of the screw placement are essential. During the screw placement, surgeons drill into the pedicle with a tap in the direction planned before surgery and adjust the direction according to the resistance from the pedicle. The force and direction are subjectively controlled by hands, and intraoperative postural variations or degeneration of the articular and transverse processes can both influence the screw entry site and screw placement direction. If there is a deviation in the direction or an incorrect entry site, the stainless-steel tap can easily penetrate the pedicle in the process of cannulation, leading to screw loosening, screw placement failure or nerve injury. Complications associated with thoracic pedicle screws by free-hand technique have been reported to be 5.1% to 31.0% . This shCagli et al.  reportedIt should be noted that the manipulation of new tap is different from the traditional tap in some aspects. For example, with the rigid traditional tap, surgeons could alter directions in tapping process either cranially or caudally or medially or laterally according to the intraoperative fluoroscopy. However, with the new tap this maneuver is not possible because of its elastic structure.Although the new tap has a certain self-guiding function, it is still necessary to complete the imaging examination and preoperative planning before operation and verify the screw channel before placement. This new tool and technique are not suitable for pedicle fractures or dysplasias. Severe osteoporosis, especially in the cortical bone, can also affect the accuracy of new tap. Moreover, this study was performed on formalin-fixed spinal specimens, the bone quality of which inevitably differ from normal vertebrae in clinical procedures. The samples in this study are relatively few,so further studies on more fresh frozen cadavers or clinical applications are necessary in the future.In summary, the new self-guided pedicle tap provides a new auxiliary method for the thoracolumbar pedicle screw placement with higher safety and accuracy compared to conventional taps. It is more convenient and economical compared with expensive methods with long learning curve such as computer navigation, 3D-printed navigation templates, or neurophysiological monitoring, promising a wide prospect of clinical application especially in primary hospitals.


The iliac fixation (IF) through the S2 ala permits the minimization of implant prominence and tissue dissection. An alternative to this technique is the anatomic iliac screw fixation (AI), which considers the perpendicular axis to the narrowest width of the ileum and the width of the screw. The morphological accuracy of the iliac screw insertion of two low profile iliac fixation (IF) techniques is investigated in this study.Twenty-nine patients operated on via low profile IF technique were divided into two groups, those treated using 28 screws with the starting point at S2, and those treated with 30 AI entry point. Radiological parameters  and clinical outcomes (early and clinic complications) were evaluated by two blinded expert radiologists, and the results were compared in both groups with the real trajectory of the screws placed.Differences between ideal and real trajectories were observed in 6 of the 9 evaluated parameters in the S2AI group. In the AI group, these trajectories were similar, except for TSV-Angle, Max-length, Iliac-width, and distance to iliac-wing parameters. Moreover, compared with S2AI, AI provided better adaptation to the pelvic morphology in all parameters, except for sagittal plane angulation, skin distance, and iliac width.AI ensures the advantages of low profile pelvic fixation like S2AI, with a starting point in line with S1 pedicle anchors and low implant prominence, and moreover adapts better to the morphological features of the pelvis of each individual. Anatomy, bone quality, and biomechanical forces are some reasons why surgeons continue to explore and study options for fixation in spinal deformity patients. Pelvic fixation is often used to correct pelvic deformity and is in widespread practice to reduce implant failure in long lumbar fusions to the sacrum and increase successful arthrodesis in the region. A variety of spinopelvic fixation techniques exist and have been described in the literature. Iliac screws, the Galveston technique, S2 pedicle screws, alar screws, and S2 alar screws have been reported to be effective in achieving rigid lumbosacral fixation. Among them, iliac screw fixation, with screws placed into the iliac wing from the posterior superior iliac spine (PSIS), has demonstrated to be the most effective method of sacropelvic fixation . Long anThe purpose of this study was to assess the anatomic correlation between ideal and real trajectories of the screws, in a group of patients who underwent sacropelvic fixation with S2AI and with AI techniques, and to establish which one adapts better to the morphological features of any given pelvis.We retrospectively evaluated the radiographs of 29 patients who underwent spinal fusion with pelvic fixation between 2017 and 2019. The patients were divided into two groups: one group treated with 28 screws with the starting point at S2 (S2AI group), and the second one, treated with 30 screws with an entry point at AI (AI group).The ideal trajectory, considering the width of the screw through the narrowest width of the ilium, was obtained by 2 blinded expert radiologists using a three-dimensional CT program (Alma). The results were matched with the real trajectory achieved by the implanted screws in both groups. The length and width of the screws, as well as any complications, were also recorded.The present study was approved by the Clinical Research Ethics Committee of the Hospital.The S2AI and the AI techniques evolved out of the established lumbosacral and sacropelvic surgical techniques.In the S2AI technique, the starting point for the sacral alar-iliac screw is located in the sacrum at the level of the lateral sacral crest, between the S1 and S2 foramen, angled 40° laterally and 40° caudally. The ideal trajectory of a sacral alar-iliac screw passes immediately above the sciatic notch, so that the bottom threads of the screw would be in contact with the cortical bone forming the upper limit of the notch, providing optimal pull-out strength .AI technique was referred in 2009 as the “modified approach” of iliac bolt placement . In the Another advantage of the AI technique is that the screw is not placed through the SI joint into the ilium as is the case with the S2AI screw. From an entry point directly into the ilium, a gently advancing probe should allow the trajectory to remain between the internal and external tables of the ilium for the entire trajectory, preserving the SI joint.Dual-energy 128 × 2 multidetector CT scanner  was used to scan the lumbar spine with a layer thickness of 1.0 mm, dual voltage of 80 and 140 kV, current of 203 and 80 mAs, Caredose 40, and acquisition of 32 × 0.6 mm. The reconstruction was performed with a pitch of 0.6 mm and threshold of bone 50f. We reconstructed multiplanar images from axial scans at a distant workstation, Syngovia Siemens, with CT dual-energy work-flow.CT was rotated, until the screw holes on each side were observed in order to measure the different radiological parameters. To obtain the ideal trajectory on each patient , CT imagSag angle: in the sagittal plane, defined as the angulation in the caudal trajectory.Tsv angle: in the transverse plane, defined as the angulation in the lateral trajectory.Max-length: defined as the maximal distance in a trajectory from S2 ala to the AIIS.Sacral distance: defined as intrasacral trajectory length.Iliac width: in the transverse plane, defined as the narrowest iliac width measured between the inner cortices.S2 midline: defined as the distance of the starting point lateral from the middle line of S2.Skin distance: defined as the distance of the starting point lateral from the skin.Iliac wing: defined as the distance of the starting point lateral from the nearest iliac wing.Then the measurements were determined as follows :Sag anglDescriptive statistical analyses, including means, standard deviations, and percentages, were used to describe all parameters determined and to summarize radiographic results. The results were expressed as mean ± standard deviation. All statistical analyses were performed at the 0.05 level of global significance using two-sided tests. Testing for baseline differences between both groups was performed using Student’s test or Wilcoxon’s test for qualitative parameters and Chi- square test for qualitative parameters. Results were analyzed using IBM SPSS software version 21.0 .A total of 28 screws with the starting point at S2 and 30 screws with an entry point through the medial ilium cortical wall were analyzed from a total of 29 patients who underwent low profile pelvic fixation.2 , and the female/male ratio was 12/2; while in the AI group, they were 65.57 years , 31.67 kg/m2 , and 10/5. The distribution of etiology was as follows: degenerative, 28.6%; deformity, 64.3%; fracture, 7.1% in the S2 group; and degenerative, 64.3%; deformity, 35.7% in the AI group , 27.49 kg/mIn the AI group, the real trajectory described correlates statistically better with the ideal entry point described in most parameters, compared to the real and ideal trajectories for S2AI. While S2AI trajectories show differences in 6 out of the 9 evaluated parameters, real and ideal trajectories in AI were all similar, except for Tsv angle, Max-length, and iliac width (Table p = 0.832), skin distance (p = 0.497), and iliac width (p = 0.233), where no statistical differences were found between both techniques . There were no cases of medial cortical wall breakage or radiculopathy in S2AI group compared with 1 instance each found in the AI group .In terms of complications, there were no cases of vascular or neurologic complications, implant prominence, anchor migration, pseudarthrosis, or iliac pain. Ten cases of external cortical wall breakage were reported in S2AI group Fig. , whereasPelvic fixation has long been a challenging area in spinal surgery and multiple studies have shown a high rate of pseudarthrosis together with poor outcomes associated with fixation failure when screws in S1 promontory are implanted without supplemental fixation .Recommended techniques for achieving additional fixation are the addition of an anterior interbody fusion device and performing supplemental fixation as a part of a complete lumbosacral fixation. This lumbosacral fixation includes alar screws, transiliac rods, and iliac post bolts. Iliac post bolts have been shown in biomechanical studies to be superior to other supplemental fixation techniques .Traditional iliac post bolts may require an additional incision or a separated fascial incision, with dissection of the iliac crest and detachment of the muscles. It may also require the implantation of offset connectors. Furthermore, this technique may be not feasible in patients who previously underwent an iliac crest autograft harvest.Low profile approaches were designed to address these problems. The entry points are in the sacrum, or in the inner table of the iliac crest, avoiding the need of additional incisions, or soft tissue dissections. Besides, the instrumentation is in-line with S1 screws, and is deep enough to avoid skin complications.The S2AI has demonstrated a drastic reduction of complications compared with the traditional iliac screws in terms of infection rates or unplanned revision surgeries .Based on our experience, we found more technical difficulties performing a S2AI technique than implementing an AI technique. Moreover, pelvic differences among sexes and regions, as previously described [Different anatomical analyses have demonstrated that the screw path from the PSIS towards AIIS provides the longest and thickest iliac plate anchor site .In addition, AI adapts better to the morphological features of the patients and S2AI, as reported in the literature, has a high incidence of implant failure, probably caused by stresses on the interface screw head and screw shaft, so AI can be an effective alternative for sacropelvic fixation .Our analysis illustrated that AI correlates better with the ideal trajectory Fig. . In factFrom our data, we can understand that AI and S2AI screws have the same advantages in terms of avoiding implant prominence. Both techniques get the same skin distance, which is bigger than the one expected in an ideal trajectory.The insertion maneuvers may be performed with fluoroscopy or computer-assisted navigation. The radiology has already been described , and it The purpose of the present study is to investigate the morphologic accuracy of iliac screw insertion using two different profile techniques. S2AI has demonstrated feasibility, efficiency, and clinical safety. It is probably the best option in those cases with a previous iliac crest harvesting due to its anchoring in the anterior position of the ilium. However, AI has the advantages of the S2AI, and moreover fits better with the ideal trajectory of an iliac screw, although more studies are required in order to verify if pseudarthrosis and clinical or biomechanical results could change. The diverse morphology found in any patient made us recommend a preoperative CT study for each case in order to decide the best choice.The anatomic entry point has the advantages of low profile pelvic fixation, with a starting point in line with S1 pedicle anchors and low implant prominence, but, moreover, it adapts better to the morphological features of the pelvis of each individual and reduces the risk of external wall breakage.


ConstantinL. A.; Phys. Rev. B2019, 99, 085117] allowing one to construct the correlation energy functionals byinterpolation of the high and low-density limits for the given semilocalapproximation. The current study extends the ACSC method to the meta-generalizedgradient approximations (meta-GGA) level of theory, providing somenew insights in this context. As an example, we construct the correlationenergy functional on the basis of the high- and low-density limitsof the Tao–Perdew–Staroverov–Scuseria (TPSS)functional. Arose in this way, the TPSS-ACSC functional is one-electronself-interaction free and accurate for the strictly correlated andquasi-two-dimensional regimes. Based on simple examples, we show theadvantages and disadvantages of ACSC semilocal functionals and providesome new guidelines for future developments in this context.The incorporation of a strong-interaction regime withinthe approximatesemilocal exchange–correlation functionals still remains avery challenging task for density functional theory. One of the promisingattempts in this direction is the recently proposed adiabatic connectionsemilocal correlation (ACSC) approach [ The accuracyof the ground-state properties of electronic systems depends on theXC functional approximation .The nonempirical XC functionals are developed by satisfying many quantummechanical exact constraints7 such as density scaling rules of XC functionals dueto coordinate transformations,10 second (and fourth) order gradient expansion of exchange and correlationenergies,17 low density, and high density limit of the correlation energy functional,20 asymptotic behavior of the XC energy density or potential,28 quasi-two-dimensional (quasi-2D) behavior of the XC energy,32 and exact properties of the XC hole.35The electronic structure calculationsof quantum chemistry, solid-statephysics, and material sciences become enormously simple since theadvent of the Kohn–Sham (KS)36 classification of nonempirical XC approximations are developedbasedon the use of various ingredients, from the simple spin densitiesand their gradients, until the occupied and unoccupied KS orbitalsand energies.43 The first rung of the ladder is the local density approximations(LDA).1 Next rungs are represented by semilocal(SL) functionals, such as generalized gradient approximations (GGA)45 and meta-GGA.51 Higher rungs are known as 3.5 rung XC functionals,58 hybrids and hyper-GGAs,75 double hybrids,81 and adiabatic connection (AC) random-phase approximation (RPA) likemethods and DFT version of the coupled-cluster theory.91Different rungs of Jacob’s ladder98 used in various sophisticated XC functionals,110 is based on the coupling-constant (or interaction strength) integralformula97V̂ee is the Coulomb operator, U[n]is the Hartree energy, Ψα[n] is the antisymmetric wave function that yields the density n(r) and minimizes the expectation value ⟨T̂ + αV̂ee⟩, with T̂ being the kinetic energyoperator, and α is the coupling constant. rs → 0 limit,where rs is the local Seitz radius), wherethe perturbative approach is valid. Thus, the well-known second-orderGörling–Levy perturbation theory (GL2)111 can be applied in the weak-interactionlimit, and Wα[n] can be expanded as43W0 = Ex and W0′[n] =2EcGL2[n]. On the other hand, the strong-interactionlimit (or low-density or rs → ∞limit) of Wα[n]is given as113W∞[n] and W∞′[n] have a highlynonlocal density dependence, captured by the strictly correlated electrons(SCE) limit,116 and their exact evaluation in general casesis a nontrivial problem.Specifically, we recall that the AC formalism,120 where the DFA formula is built by interpolating between the weak-and strong-interaction regimes. The α → ∞ limitis approximated by semilocal gradient expansions (GEA) derived withinthe point-charge-plus-continuum (PC) model.112 Based on this form, the ISI has been tested for various applications.121 Also, several modificationsof the ISI have been suggested123 as well as the PC model itself such as the hPC124 or modified PC (mPC),110 whichwas found to be more robust for the quasi-two-dimensional (quasi-2D)density regime.In particular, one of the successfulattempts at practical usabilityof the AC DFAs came through the interaction strength interpolation(ISI) method by Seidl and co-workers110 showing the alternative path of construction of semilocal correlationenergy functionals. The ACSC formula interpolates the high- and low-densitylimits for the given semilocal DFA directly, in contrary to the standardpath where the interpolation is done at the local LDA level and thencorrected by gradient or meta-GGA corrections.46 We recall that in ref 44 high-density formula and mPC model showing similaror improved accuracy over its PBE precursor proving in the same timethe evidence for the robustness of ACSC construction.Recently based on the ISI formula, the adiabaticconnection semilocalcorrelation (ACSC) method was introduced,Motivatedby the progress in this direction, this paper extendsthe ACSC method at the meta-GGA level and provides new insights intothis context.46 DFA. Following that, we applyACSC correlation energy functionals to some model systems (Hooke’satom and H2 molecule) and real calculations  to show some advantages and currentlimitations of ACSC functional construction. Lastly, we conclude bydiscussing the possible advances of the present construction.In the following, we briefly recall some aspectsrelated to ACSCfunctional construction and investigate a few available approximationsfor the high- and low-density regimes. Based on that, we propose anextension of the ACSC method to the meta-GGA level using the high-and low-density limits of the Tao–Perdew–Staroverov–Scuseria(TPSS)120 withw0, w0′, and w∞, w∞′ denotethe approximation for energy densities for high- (or weak-interaction)and low-density (or strong-interaction) limits, respectively. Consideringthe accuracy of (i)wc,α(r) integrand in Wα[n] contains a spurious term proportional to α–1 in its strong-interaction limit (α → ∞),112 which has been corrected in refs (122The interpolation formula is usedto define the  in refs  and (115(ii)110 hPC,124 or the ones derivedfrom semilocal DFA via the procedure described in ref or much less time-consuming variants such as mPC,d in ref  Note tha(iii)125 However, evaluation of the GL2correlation energy density on the numerical grid would likely be computationallyquite expensive. Hence, in ref  and GL2 limit., in ref , the nonFollowing ref , the ACSw0(r) and w0′(r) approximations are constructed as110 where τ(r) = ∑j=1occ|∇ϕj(r)|2/2 is the KS noninteracting kinetic energy density, with ϕj(r) being the one-particle jth occupied KS orbital. We underline that the Laplacianof the density (∇2n) contains informationthat is is already encapsulated in τ,126 such that many meta-GGA XC functionals do not consider ∇2n as an ingredient.In this work, we extend the ACSC DFA by consideringall input quantities at the semilocal (SL), meta-GGA level. For instance,the (i)127 thus, they can beeasily applied in the present construction. The quantitative comparisonof the accuracy of these SL-GL2 models with reference second-orderGL2 correlation energy data is reported in ref have already been derived;d in ref  in Table(ii)The meta-GGA SL-GL2,such as TPSS-GL2DFA, is one-electron self-interaction free, giving exactly zero forthe hydrogen atom, which is not the case for PBE-GL2.There are alsotwo prime motivations behind the extension of ACSCfunctionals to the meta-GGA level:w∞(r) and w∞′(r).In the next section, we address the choice of w0(r) and w0′(r) (where the energy density wα(r) is defined by Wα = ∫dr wα(r)) in the form of TPSSexchange (w0(r) = n(r)ϵxTPSS) and TPSS-GL259 (w0′(r) = 2n(r)ϵcTPSS-GL2), respectively. In the case of w∞(r) and w∞′(r), the choice isnot so simple due to various variants available in the literature.As was noted before, the form of w∞(r) and w∞′(r) implies the incorporationof important physics in the ACSC formula, i.e., the quasi-2D regimevia the mPC110 model or very accurate performancefor weak and strong-interaction regime via the hPC model developedrecently.124 However, both mPC and hPCare simple GGA-level approximations of SCE formulas, which are notone-electron self-interaction free.124 Therefore,the utilization of these GGA models might impact the performance ofACSC meta-GGA DFA. To overcome this limitation, one can develop themeta-GGA model for the TPSS strong-interaction129 regime as was done in appendix D in ref (ExcDFA = ExDFA + EcDFA), the corresponding coupling-constant integrand WαDFA can be derived from the following formulaTo constructACSC meta-GGA DFA, we fix the D in ref . Thus, fW∞TPSS (W∞′TPSS (w∞(r) and w∞′(r), respectively.The latter quantities incorporate all physically meaningful features,i.e., canceling one-electron self-interaction and proper behaviorfor the quasi-2D regime (shown later), which was also the case forthe mPC model.110 Based on the above consideration,we construct the TPSS-ACSC correlation functional using w0, w0′ and w∞, w∞′ energy densities.Thus, for the low-density limit ofthe TPSS functional, we obtain the W∞TPSS 17 and W∞(W∞′TPSS 18 express →0 (w0′ → −∞),  model) behaving inthis limit as110w0′ → 0, it givesEcTPSS-ACSC = 0 whenever EcTPSS-GL2 = 0. The TPSS-GL2 correlation energy density vanish whenever τ= τW, and ζ = 1, where τW isthe von Weizsäcker kinetic energy density.131 Thus, for one-electron systems, where EcTPSS-GL2 =0, the TPSS-ACSC correlation energy is exact, showing that the functionalis one-electron self-correlation free.The final TPSS-ACSCformula diverges to −∞ when 132  correlation136 energy densities. One can note that theACSC formula is accurate in the low-density limit (rs ≥ 20), while in the high-density limit (rs → 0), it diverges as ∼rs–1/2, thus faster than the exact behavior (∼ln(rs)). Nevertheless, in the high-density limit, the exchangeenergy dominates over the correlation, such that this failure of theACSC correlation should be compensated by the proper choice of theexchange functional part. This can be considered a drawback of ACSCconstruction because it might lead to some issues with a lack of compatibilitybetween standard semilocal exchange functionals and the ACSC correlationfunctionals . We will address thisissue in the following.At this point, analysisof the behavior of the TPSS-ACSC correlationenergy is required. In W∞TPSS = ∫dr w∞TPSS(r) and W∞TPSS = ∫dr w∞TPSS(r) expressions, whichare reported in 115 PC, mPC, hPC, and PBE  formulas fromref  SCE values  being almost 3 times better than the one obtained for a very accuratehPC model. This is partially because the former correctly removesthe one-electron self-interaction in W∞TPSS, whichis taken into account in all GGA W∞ approximations. Nonetheless, even without hydrogen atom contribution(reported in parentheses), the mean absolute relative error (MARE)of TPSS W∞ presents the best performancefor this model (MARE = 0.44%), closely followed by hPC (MARE = 0.48%)that are twice better than the original PC variant.We first test the accuracy of fromref . In the W∞′ the overall performanceof theTPSS model is worse than the one observed for hPC, being in line withthe results reported for PC. This can be due to the fact that W∞′TPSS in the slowly varying density limit does not recovercorrectly the gradient expansion of the PC model. The problem liesin the H2 function  quasi-2D electron gas of fixed 2Delectron density (rs2D = 4) as a function of the quantum-well thickness L as was also done in ref  = λn and the system approaches the 2D limitwhen λ → ∞. In this limit, the XC energy is finiteand negative, i.e., limλ→∞Exc[nλz] > −∞. We reportthisin W∞ and W∞′ give correct behavior for a whole range of quantum-well thickness L.Further, we perform the comparison of e in ref . The quaW∞ and W∞′ reproduce reference SCE data with quitea good accuracy and also some other important features, e.g., goodperformance in the quasi-2D regime, removing one-electron self-interaction.This possibly indicates that the description of all nonlocal featuresof the SCE model can be done only by the utilization of nonlocal ingredientssuch as τ. This is the first important finding of the presentstudy.A brief summary of all important features of strong-interactionmodels is given in 143 For molecules, we have performedthe HF calculations in the ACESII144 programusing the uncontracted cc-pVTZ142 basissets and geometries taken from refs 143 For mn in ref  the utilcTPSS, ϵcTPSS-GL2, and ϵcTPSS-ACSC for the Ar atom. Whenever s is small, ϵcTPSS-GL2 startsto depart from ϵcTPSS, diverging when s = 0. However, ϵcTPSS-ACSC is well-behaved everywhere.As noted before, both considered correlation functionalsare one-electronself-interaction free, which is visible in the case of the H atom.In most cases, TPSS-ACSC performs in line with its TPSS counterpart,indicating that the correlation effects are well represented in theACSC energy expression. To visualize the correlation densities, in As to the molecules, we note that TPSS-ACSC performsvery wellfor the majority of systems, being slightly better than the TPSS functional.This again confirms the robustness of the correlation functional construction.147 using EXXreference orbitals. We recall that for small values of confinementstrength ω, the system is strongly correlated, whereas for largevalues of ω, we enter a weak-interaction regime. Thus, the modelprovides an excellent tool for testing the functional performancein these two regimes. We underline that in all following calculations,all TPSS-like correlation functionals have been combined with theTPSS exchange energy functional in order to obtain XC energies.In W∞ and W∞′ inthe form given by For medium and large values of ω, the TPSSand TPSS-ACSCfunctionals perform very similarly, giving in the weak interactingregion a very small relative error (RE) similar to those of exactGL2 and ISI XC functionals. In a strong-interaction regime, in turn,the TPSS-ACSC improves over its TPSS precursor. We note that in thelatter regime, the TPSS-ACSC functional should recover, in principle,the ISI functional data due to the inclusion in both energy expressionsthe 2 molecule, in a restrictedformalism,149 which is one of the mainDFT challenges.151 This is reported in 2 molecule is largely stretched. As pointed outpreviously, the functional-driven error dominates most of the semilocalDFAs. Thus, the utilization of HF densities still gives a valid pictureof the performance of semilocal DFAs for the whole range of distancesof H2.Now we turn attention to anothertwo-electron example where wemay encounter a strong-interaction limit, namely, the potential energysurface for the dissociation of the HR/R0 > 3.Asymptotically,the TPSS-ACSC energy goes almost to the same value as the ISI method,with W∞ and W∞′. This is a very interesting finding,possibly suggesting the dominant role of the strong-interaction limit(EGL2 → −∞),leading in the asymptotic limit to ExcISI → W∞ + 2W∞′(1 – 1/q ln(1 + q)) with q = (Ex – W∞)/W∞′.124 In the latter,in turn, the asymptotic limit is governed rather by the mutual errorcancellation effect in the TPSS-ACSC energy expression. This is dueto the fact that TPSS-GL2 energy expressions do not diverge for large R/R0, meaning that at the asymptoticregion, 154 within the SL-GL2 formula.One can note that, in general, the TPSS-ACSC functionalperformsvery similarly to TPSS, especially near equilibrium distance. Morevisible differences between these two DFAs can be seen for largerdistances on limit10 for la156 atomization energies of six small size molecules, obtained usingSCF orbitals and densities. One can note that the TPSS-ACSC functional,in general, gives results that are twice worse than for the TPSS counterpart, which yields an MAE of 7.6 kcal/mol.The same trend for the AE6 benchmark occurs when we feed the TPSS-ACSCand TPSS total energy expressions with HF orbitals. This indicatesthe following things:145 This is most possibly related to the ACSC model itself, which wasnot designed to be accurate in the high-density limit where most ofthe chemical application takes place.The major part of the error for the TPSS-ACSC functionalis related to functional-driven error.Because both TPSS and TPSS-ACSC utilize the same semilocalTPSS exchange, the much larger error observed in the latter mightsuggest the lack of compatibility between exchange and correlationfunctionals (there is no error cancellation effect). The correlationenergies themselves are quite accurate as shown in Let us focus on self-consistentresults (@SCF) obtained withinthe generalized KS (gKS) scheme. As an example, we report in 46 by calibrationof the second-order gradient expansion parameter (μ = 0.235).We note that in general, this parameter might vary based on the natureof the localized (such as atoms) or delocalized systems (solids).At this point, using μ = 0.40, we have observed a significantreduction of MAE for AE6 obtained at @SCF densities to 6.63 kcal/mol.To test this possibility, we have performed ad hocmodificationof the TPSS exchange functionalFinally, the performance of the constructed functionals is alsobenchmarked for other molecular test cases such as atomization energies,barrier heights and weeks, and covalent interactions. These resultsare reported in In this work, we have constructed a semilocalmeta-GGA correlation energy functional, based on the ACSC method proposedin ref . The cor2 molecule) and real-life calculations (atomization energies)showing some advantages and disadvantages of ACSC construction. Fromthis broad perspective, we can conclude that, although the ACSC methodholds promise for proper description of a strong-interaction regime,it is still in its infancy, which implies that there is still muchspace for improvement. The most important conclusions of this studyare as follows:W∞TPSS and W∞′TPSS) reproduces quite well reference SCE data. Moreover, both possesssome other important features, e.g., good performance in the quasi-2Dregime and removing one-electron self-interaction. Thus, both formulascould be effectively applied in the construction of ACSC and ISI-likeformulas.The strong-interaction limit obtained from the semilocalTPSS functional formula (2 molecule cases), e.g., via proper incorporation of thelocal gap model.154Although our numerical testssuggest that the strong-interactionlimit of semilocal TPSS-ACSC correlation is well represented, thesemilocal GL2 part may need some amendment . As was shown the ad hoc modification of TPSSexchange gives some hints in that direction.The new correlation TPSS-ACSC functional is nonempirical, one-electronself-interaction free accurate for small atoms and molecules. We providea careful assessment of the TPSS-ACSC functional base on some modelsystems (the uniform electron gas, Hooke’s atom, stretchedHSome of these new developments in the ACSC context willbe addressedin a future study.


Percutaneous iliosacral (IS) screw fixation and trans-iliac trans-sacral (TITS) screw fixation are clinically effective treatments of posterior pelvic sacroiliac fractures. In order to accurately assess the sacrum position relative to the pelvis, pelvic incidence (PI) is a commonly utilized radiographic parameter in sagittal view. This study aimed to investigate and compare the surgical outcomes and radiographic parameters of IS or TITS screw fixations for the treatment of posterior sacroiliac complex fractures with different PI values.The data on patients with posterior pelvic sacroiliac fractures who underwent percutaneous IS or TITS screw fixations, or both, at a single level I trauma center between January 2017 and June 2020 were reviewed. We documented the patient characteristics and fracture types, reviewed surgical records, and measured the radiographic parameters via plain films and multi-planar computed tomography (mpCT) images. Radiographic variations in PI, sacral slope, pelvic tilt, sacral dysmorphism, pelvic ring reduction quality, screw deviation angles, screw malposition grading, and iatrogenic complications were documented and analyzed.p = 0.027 and 0.003 in the IS and TITS screw groups, respectively). Patients with larger PI values were at a significantly increased risk of screw malposition in the TITS screw group (p = 0.049), with no association in the IS screw group. Logistic regression confirmed that a larger PI value was a significant risk factor for screw malposition in the TITS screw group (p = 0.010). The post-operative outcomes improved from poor/fair (at 6 months) to good/average (at 12 months) based on the Postel Merle d'Aubigné and Majeed scores, with no significant differences between subgroups.A total of 85 patients were included, and 65 IS and 70 TITS screws were accounted for. Patients were divided into two groups according to screw fixation method and further divided into four sub-groups based on baseline PI values. The PI cutoff values were 49.85° and 48.05° in the IS and TITS screw groups, respectively, according to receiver operating characteristic analysis and Youden's J statistic. Smaller PI values were significantly correlated with sacral dysmorphism (Both percutaneous IS and TITS screw fixations are safe and effective treatments for posterior pelvic sacroiliac fractures. Due to the higher risk of screw malposition in patients with larger PI values, it is crucial to identify potential patients at risk when performing TITS screw fixation surgery.Level III. Pelvic fractures constitute about 3–8% of all skeletal injuries and are often caused by high-energy trauma, such as car collisions, falls from height, or crush injuries –3. The pPercutaneous reduction and fixation with iliosacral (IS) screws was first introduced by Vidal et al. in 1973, followed by the trans-iliac trans-sacral (TITS) screw technique of Gardner and Routt in 2011 , 7. BothAnatomically, the position of the sacrum with respect to the pelvis varies with the individual, and so does the shape and surface area of the sacroiliac joint. Pelvic incidence (PI), first introduced by Legaye et al. , is an iThe authors anecdotally experienced difficulties with the insertion of IS and TITS screws in patients with large PI values and recognized that the relative positions of the sacrum and pelvis might have an influence on screw insertion. Therefore, this study aimed to investigate and compare the surgical outcomes and radiographic parameters of IS or TITS screw fixations for the treatment of posterior sacroiliac complex fractures with different PI values. To the best of our knowledge, no previous studies have explored the clinical significance of PI values in the treatment of posterior pelvic sacroiliac fractures with IS and TITS screws.We performed a single-center, retrospective cohort study at a level I trauma center with the approval of the relevant institutional review board. A retrospective chart review was conducted and documented by consecutively reviewing the data of patients with pelvic sacroiliac complex fractures. The inclusion criteria of the study were: (1) patients with pelvic sacroiliac complex fractures with or without an anterior pelvic ring fracture or acetabular fracture; (2) patients who underwent percutaneous IS or TITS screw fixation or both; (3) patients who completed all the comprehensive pre- and post-operative imaging, including radiographs of the anterior–posterior (AP) view and inlet and outlet projections as well as multi-planar computed tomography (mpCT) of the pelvis; and (4) patients who had completed at least 1 year of post-operative follow-up. Patients were excluded from the study if (1) the pelvic sacroiliac complex fracture was associated with pathological conditions such as malignancy; (2) patients lacked the required imaging data; and (3) patients were under 16 years of age. A total of 85 patients were collected and included in this study between January 2017 and June 2020. The data encompassed comprehensive records of each patient’s demographic characteristics, comorbidities, pre- and post-operative radiographic parameters, as well as complications.Plain films of AP, inlet, and outlet projections and mpCT of the pelvis were acquired for preoperative evaluation at the emergency department or after admission. Image assessment and radiographic parameter measurement were conducted via the Picture Archiving and Communication System . Radiographic evaluation was performed using the established method in an unbiased fashion by two independent certified surgeons of our orthopedic department who did not participate in the surgeries.Pelvic sacroiliac complex fractures were further classified using the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) classification, Tiles classification, and Young-Burgess classification , 13. SagTo access and quantify the extent of screw malposition, a grading system proposed by Smith et al.  was usedSurgical planning was conducted with a comprehensive review of the preoperative plain films and mpCT images. Based on the preoperative planning, the surgical position was decided upon based on the fracture pattern, surgical approach, and concomitant injury. The supine position was used if patient had an anterior pelvic ring fracture or the presence of a concurrent intra-abdominal injury. The prone position was chosen in cases with severe spinopelvic dissociation or a vertical displacement fracture of the sacral body and without an anterior pelvic ring fracture. The patient was laid on a radiolucent table  under general anesthesia. One or two folded blankets were put underneath the buttock to lift the patient off the table. The elevated height was adjusted depending on the pelvic deformity and patient’s physique. Reduction was carried out using either the open or closed method. Typically, closed reduction was attempted as the initial approach. However, if there was poor fracture reduction quality with closed reduction or there were additional fractures to be addressed, open reduction was performed. An intraoperative single-arm fluoroscopic intensifier  was used to visualize and diagnose pelvic discontinuity with serial pelvis projections, including AP, inlet/outlet, Judet, and sacral lateral views to ensure accurate screw position and reduction quality.IS screws were inserted in the first sacral segment when possible, and TSIS screws were placed in the second sacral segment, rather than the first segment, when encountering sacral dysmorphism with a narrow corridor of the first sacral segment. To minimize technical errors, pre-drilling with a 2.0-mm K-wire was performed before inserting the 7.0-mm cannulated screw . Oblique IS screws should be placed such that they are obliquely aligned posteriorly to anteriorly and inferiorly to superiorly while simultaneously crossing the sacroiliac joint as perpendicularly as possible. TITS screws were placed such that they crossed through the bilateral sacral ala and parallel to the ground when the patient was in the true supine position without radiolucent table tilting.Clinical outcomes were evaluated by an independent medical professional, and the assessments were conducted at 6 and 12 months post-operatively. The Postel Merle d'Aubigné and Majeed scores were utilized to assess the clinical outcomes. The Postel Merle d'Aubigné score assesses hip function and outcomes, focusing on pain, mobility, and walking ability; each of its components is rated on a scale of 0 to 6, with a total score of 18 classified as excellent, a score of 17 as very good, a score of 15–16 as good, a score of 13–14 as average, a score of 9–12 as poor, and a score  of < 9 as bad . The Majt test was conducted for continuous data. Possible risk factors were analyzed by logistic regression. P < 0.05 (5%) was set as the cutoff value and considered statistically significant. The receiver operating characteristic (ROC) curve and Youden's J statistic were used to calculate the optimal PI cutoff value.SPSS 25.0  was used for data processing and analysis. Categorical variables were compared using the chi-square test and Fisher’s exact test. The independent-samples In our study, a total of 85 patients with 135 screws were enrolled and extracted from our pelvic ring fracture database for analysis between January 2017 and June 2020. Patients were divided into two groups based on the percutaneous screw fixation technique: an IS screw group (65 screws) and a TITS screw group (70 screws). Then, we further divided them into four sub-groups based on the PI index value. To assess the PI values and the corresponding numbers of malpositioned screws, the cutoff PI values were set according to ROC analysis and Youden's J statistic to 49.85° in the IS screw group and 48.05° in the TITS screw group. Tables n = 74), followed by fall (n = 23) and crush injuries (n = 22). Given the various types of pelvic fracture, the most common fracture pattern was AO/OTA classification B , Tile classification B , and Young–Burgess classification APC II (n = 25) and LC 1 (n = 25) in the IS and TITS screw groups, respectively. To minimize soft tissue damage, closed reduction with percutaneous screw fixation was the primary surgical approach. Considering that the majority of the high-energy fracture patients might also have suffered a concurrent anterior pelvic ring fracture, acetabular fracture, and/or other traumatic injuries, our surgical approach favored performing the procedure with patients in the supine position. However, in situations where patients had mild concurrent injuries and more complex posterior pelvic sacroiliac fractures, the prone position was adopted for better access during surgery. Ultimately, the decision regarding the surgical position was based on the surgeon's experience and preference. In our institute, instead of multiple-staged operations for patients, simultaneous fixations were performed in a single-stage surgery for both anterior and posterior pelvic ring fractures when the patient’s condition permitted. All patients underwent the surgery successfully without major iatrogenic complications, such as neurovascular, intra-abdominal, or genitourinary organ injuries.In both the IS and TITS screw groups, the patient’s demographic characteristics were comparable, with no significant differences despite the small and large PI values. In all groups, the primary injury mechanism was motor vehicle accident . The IS screws were usually inserted at the level of S1 (96.92%), and the TITS screws at the level of S2 (74.29%). The screw malposition rates were 3.07% and 22.86% in the IS and TITS screw groups, respectively. In addition, patients with larger PI values were at significantly increased risk of screw malposition in the TITS screw group (p = 0.049), but such an association was not found for the IS screw group. The ADIO measurements of the IS and TITS screw groups showed no significant difference between patients with different PI values in both the axial and coronal views.The radiographic parameters were measured pre- and postoperatively and documented as listed in Tables p = 0.010. Interestingly, even with radiographic findings of screw malposition, no correlation with poor clinical outcomes or complications was found; even with a grade 3 perforation, no patient required revision surgery for screw adjustment. Among all the patients with grade 3 screw perforation, postoperative neurologic function could not be determined in one patient with a brain injury, and we decided to apply the utmost caution by removing the malpositioned screw in a concurrent debridement surgery for wound dehiscence to prevent potential undiagnosed neurological conditions.The results of the logistic regression analysis are listed in Table At 6 and 12 months post-operatively, the assessment using the Postel Merle d'Aubigné and Majeed scores revealed acceptable results for all four groups Tables  and 4. APelvic sacroiliac complex fractures are mostly caused by high-energy trauma, mostly in motor vehicle accidents. The percutaneous surgical approach is a popular method for restoring the pelvic anatomy and securing rigid fixation. Both IS and TITS screw fixation are excellent percutaneous fixation methods for surgical stabilization. However, due to the complexity of the sacroiliac structure, accurate screw placement with minimal soft-tissue dissection is highly technically demanding. Our study showed that a percutaneous approach provided rigid internal fixation with good reduction quality and clinical outcomes. However, there was a potential high risk for screw malposition while inserting the TITS screws. In addition, patients with larger PI values were found to be at significantly higher risk for TITS screw malposition.Accurate screw placement remains of paramount importance, as it is related to pelvic construct stability and optimal outcomes. The screw malposition rate varies over a wide range (0–58.8%) in the published literature –27. Our p = 0.133). Interestingly, in the TITS screw group, the screw malposition rate was significantly lower in patients with smaller PI values (13.51%) when compared to those with larger PI values . This result can be explained by the difficult positioning of an intraoperative fluoroscope to obtain clear visualization of pelvic inlet and outlet projections in said patients. In general, in order to acquire good-quality images of inlet and outlet projections, the central ray projects at an angle 45° cephalic and 45° caudal to best demonstrate the pelvic ring configuration, and the projection angle might require minor adjustment to account for anatomical variations among individuals in order to optimize surgical outcomes. Ricci et al. found that, to achieve the intraoperative visualization of special bone corridors, an average caudal tilt of 21° of inlet angle was needed to profile the S1 anterior body; meanwhile, the average cephalad tilt outlet angle was 63° perpendicular to the S1 vertebral body and 57° for the S2 level [After analyzing the associated radiographic parameters, we found that the values of PI had a significant influence on the screw malposition rate in TITS screw fixation patients. In the IS screw fixation group, a 0% screw perforation rate was observed in patients with smaller PI values, compared to 8.33% in patients with larger PI values , with logistic regression analysis also confirming that larger PI values were a significant risk factor in the TITS group (p = 0.010). We found that, even with an oblique osseous pathway of the sacral isthmus when inserting the IS screw, the surgeon was able to modify the screw trajectory while determining the safety zone and to make it slightly deviate from being perpendicular to the sacroiliac joint. This resulted in fewer patients with screw malposition.The PI was defined as the angle between the line perpendicular to the sacral endplate at its midpoint and the line connecting this point to the center of the femoral heads , 29. In p = 0.027 and 0.003, respectively). When sacral dysmorphism is present, an oblique and angulated trajectory makes screw placement difficult and demanding, even for experienced surgeons. However, no correlation was found between sacral dysmorphism and screw malposition rate in our study. This lack of correlation can be explained by the frequent insertion of IS screws at the level of the first sacral segment S1 (96.92%) in our study, while TITS screws were often placed at the level of the second sacral segment, S2 (74.29%). In the preoperative planning of IS screw placement, it was easier to modify the screw trajectory angle at the upper sacral segment in patients with sacral dysmorphism. Moreover, the second sacral segment was less influenced by the sacral dysmorphism, which should be considered when aiming for safe TITS screw placement.Sacral dysmorphism is a common anatomical variant, which was first characterized as collinearity, mammillary processes, noncircular and misshapen anterior first sacral neuroforamina, and residual S1/S2 disc space by Routt et al. on plain radiographs . In addiConsidering the close proximity of several neurovascular structures, the potential risk of neurovascular bundle damage due to screw malposition is a major concern in IS and TITS screw osteosynthesis procedures. Published studies have reported neurovascular complication rates ranging from 0% to 3.2% , 26, 33.Whether to perform reduction with precise and quick percutaneous screw placement with the patient in the supine or prone position is still under debate. Initially, IS and TITS screw fixation procedures were performed with the patient in the prone position, but in 1992 Routt et al. introduced the use of the supine position when performing the surgery . The proOur work had some limitations. First, the study design was a single-center, retrospective study with two groups, which were then divided into four sub-groups with small and unequal sample sizes, and this may have compromised the generalizability of our results. Second, all the procedures were performed by a single surgeon. With an improvement in surgical performance over time, a decrease in the screw malposition rate could be expected, which could affect surgical outcomes. Despite these inherent limitations, our work has important implications for surgeons performing TITS screw fixation in patients with large PI values, as preoperative surgical planning is paramount when attempting to reduce screw malposition and potential neurovascular complications Fig .Fig. 2A Percutaneous IS and TITS screw fixations are safe, effective, and minimally invasive procedures to treat posterior pelvic sacroiliac fracture. These techniques have become increasingly popular. Our study demonstrates that, for TITS screw fixation, larger PI values are a risk factor for screw malposition, highlighting their potential role in ensuring good surgical outcomes.


Two-dimensional (2D) ice I is atomic-level ice that is composed of two interlocked atomic layers saturated with hydrogen bonds. It has recently been experimentally observed, but its properties have yet to be clarified. Accordingly, we theoretically studied the hydrophobic properties of 2D ice I. On the contrary, a simulation of a hydrogen fluoride molecule on a 2D ice surface manifested that it destroyed the 2D ice structure and connected new hydrogen bonds with water molecules. Investigations of the interfacial effect between 2D and three-dimensional (3D) ice films indicated that the network structure of 2D ice was not destroyed by a 3D ice surface, as the former was saturated with hydrogen bonds. However, the surface of 3D ice reorganized to form as many hydrogen bonds as possible. Thus, the 2D ice film was hydrophobic and inhibited the growth of 3D ice. This shows that if 2D ice can be produced on an industrial scale, it can be used as an anti-3D-icing agent under low temperatures. Water ice is a ubiquitous substance. More than 19 three-dimensional 3D) ice phases have been observed under extreme temperature and pressure conditions at a laboratory scale . In addiD ice phaAs an atomic-level material, 2D ice is likely to be of significance in the fields of material science, atmospheric science, and biology, among others ,16,17,18+ ions on the graphene surface. The Li+ ions were placed on the surface with different distances. It was found that the system was stable at the position of 1.84 Å [The DFT was introduced by Professor Walter Kohn, which uses electron density instead of wave function to describe multi-electron systems ,20. Manyf 1.84 Å . Nakada f 1.84 Å . Boukhvaf 1.84 Å .In this work, using DFT methods, we simulated the adsorption properties and interface effects between 2D ice and water monomer and 3D ice. The results indicate that 2D ice is hydrophobic and inhibits the growth of 3D ice. Thus, if 2D ice can be produced on an industrial scale, it would be a useful anti-icing agent and a valuable lubricant.To demonstrate the hydrophobicity of 2D ice, we simulated the adsorption behavior of a water molecule on the 2D ice (001) surface to determine whether this monomer could break the 2D ice structure and construct new hydrogen bonds with the 2D ice film. As the length of a hydrogen bond is approximately 1.8 Å, the monomer was placed at approximately 1.9–2.5 Å above the 2D ice surface. We constructed three kinds of configurations by adjusting the monomer orientations, namely two horizontal configurations a,b and oAfter optimization, the total energies of the three systems depicted in Two comparative models of HF and H2O monomers in parallel with one O-H bond of H2O at the 2D ice surface were optimized. The distance of the fluorine and hydrogen atoms was set as 1.927 Å. After geometry optimization, the HF molecule clearly broke the film structure and reformed two hydrogen bonds with two water molecules at the 2D ice surface b. On theSubsequently, we studied the interfacial effect between 3D and 2D ice. To integrate the two types of films into one periodic cell, hydrogen-ordered ice Ic was used as the 3D ice because its lattice constant is well matched with that of 2D ice. The 3D ice film was superimposed onto the 2D ice a, and thThe results of the simulation of the interfacial effect between two 3D ice films are shown in The DFT code CASTEP was used to identify the geometries of water adsorption on 2D ice. The CASTEP program was originally developed in the Theory of Condensed Matter Group at Cambridge University, UK. It is a quantum mechanical code for electronic structure calculation based on the DFT method. Its advantage is that it can determine the ground state electronic structure of a system by solving the Schrödinger equation without using any experimental  data and only five basic constants , such as the band structure, optical properties, and mechanical properties. The basic method of using the CASTEP code to calculate the electronic structure is as follows: A set of Kohn–Sham equations of a single electron is calculated by using the plane wave approximation method. The energy and wave function of the single electron orbit are obtained, and the ground state energy of the electron system is calculated. Using the periodic boundary conditions and the Bloch theorem, the wave function is expanded into the plane wave basis set. The real potential energy inside the core is modeled by norm-conserving and Ultrasoft pseudopotential. The CASTEP code can be used to simulate a variety of materials, including crystalline solids, surfaces, molecules, liquids, and amorphous materials . For the exchange correlation energy between electrons, DFT uses electron density instead of wave function as the basic variable, but this does not seem to solve the problem of calculating the complexity of the exchange correlation between electrons . When KoGiven the large fluctuations in the electron densities, we used the GGA method for geometry optimization. According to our work on 3D ice phases, the revised PBE functional is the optimal exchange–correlation functional for phonon calculation ,33,34,35With reference to the work of Jiang , we consIn the interfacial effect simulations, to match the coordinates of 2D ice, we selected ice Ic as the 3D ice sample. The lattice constants of ice Ic were set as follows: Owing to the challenges in experimentally observing atomic-level 2D ice films , researcAn analysis of the interfacial effect between a 2D ice film and 3D ice showed that the surface of the 3D ice reorganized to form more hydrogen bonds when it was placed close to the 2D ice film. In contrast, two 3D ice films placed in parallel at a large distance from each other were easily connected by hydrogen bonds. These results suggest that 2D ice inhibits the growth of 3D ice. Therefore, 2D ice is a promising anti-icing material. In addition, a multilayer framework of 2D ice may exhibit excellent lubricating properties, similar to those of graphite. Experimental observations are expected to be made in the future.