BACKGROUND:Clinical studies suggest that both bone quality and excessive crown-to-implant ratio are factors that affect the success rate of implant surgery,but there is no consensus on how large the crown-to-implant ratio under each bone quality will affect the prognosis of implant repair.OBJECTIVE:To analyze the stress and strain of bone tissue around implant restorations with different crown-to-implant ratios under different bone types after stress loading using three-dimensional finite element method.Combined with the Frost bone mechanics regulation system theory,the physiological limits of bone strain were observed for each bone type within a certain range of crown to implant ratios.METHODS:Cone beam CT data were selected from a patient to establish solid bone block models with four different bone types(class Ⅰ bone:cortical bone thickness 3 mm+dense cancellous bone,class Ⅱ bone:cortical bone thickness 2 mm+relatively dense cancellous bone,class Ⅲ bone:cortical bone thickness 1 mm+relatively low-density cancellous bone,class Ⅳ bone:cortical bone thickness 1 mm+low-density cancellous bone).Implant restorations with five different crown-to-implant ratios(1,1.5,2,2.5,and 3)were created on each bone block model,for a total of 20 models.Vertical and oblique forces were applied to the dental crown to observe the von Mises stress values,strains,and displacement of the cortical and cancellous bones,as well as the degree of implant displacement.RESULTS AND CONCLUSION:(1)In the class Ⅰ bone model,when the crown-to-implant ratio reached 3 under oblique loading,the cortical bone strain exceeded the physiological limit.In the class Ⅱ bone model,under oblique loading,when the crown-to-implant ratio reached 2.5,the cortical bone strain exceeded the physiological limit.In the class Ⅲ bone model,under oblique loading,cortical bone exceeded the physiological limit when the crown-to-implant ratio reached 2.5,while cancellous bone reached the critical physiological limit at 1.In the class Ⅳ bone model,under oblique loading,when the crown-to-implant ratio reached 1.5,2,2.5,and 3,the cortical bone strain exceeded the physiological limit.In the class Ⅳ bone model,all five crown-to-implant ratios of cancellous bone exceeded physiological limits.(2)Under vertical load,the cancellous bone strain exceeded the physiological limit when the crown-root ratio reached 1,2,2.5,and 3 in the class Ⅲ bone model,and when the cancellous bone strain of the five crown-root ratios in the class Ⅳ bone model exceeded the physiological limit.(3)Under oblique or vertical load,the implant displacement of the 20 groups of models did not exceed 100 μm.(4)From the perspective of biomechanics,when patients with insufficient bone height choose implant restoration,the crown-root ratio that class Ⅰ bone can tolerate is up to 2.5 times,the crown-root ratio that class Ⅱ bone can tolerate is up to 2 times,and the crown-root ratio that class Ⅲ and class Ⅳ bones can tolerate is up to 1 times due to excessive strain of cancellous bone;but the crown-root ratio that cortical bone in class Ⅲ bone can tolerate is up to 2 times.Whether class Ⅲ bone can tolerate implant restoration with a high crown-root ratio and whether cancellous bone can tolerate higher strains needs further study.

BACKGROUND:Clinical studies suggest that both bone quality and excessive crown-to-implant ratio are factors that affect the success rate of implant surgery,but there is no consensus on how large the crown-to-implant ratio under each bone quality will affect the prognosis of implant repair.OBJECTIVE:To analyze the stress and strain of bone tissue around implant restorations with different crown-to-implant ratios under different bone types after stress loading using three-dimensional finite element method.Combined with the Frost bone mechanics regulation system theory,the physiological limits of bone strain were observed for each bone type within a certain range of crown to implant ratios.METHODS:Cone beam CT data were selected from a patient to establish solid bone block models with four different bone types(class Ⅰ bone:cortical bone thickness 3 mm+dense cancellous bone,class Ⅱ bone:cortical bone thickness 2 mm+relatively dense cancellous bone,class Ⅲ bone:cortical bone thickness 1 mm+relatively low-density cancellous bone,class Ⅳ bone:cortical bone thickness 1 mm+low-density cancellous bone).Implant restorations with five different crown-to-implant ratios(1,1.5,2,2.5,and 3)were created on each bone block model,for a total of 20 models.Vertical and oblique forces were applied to the dental crown to observe the von Mises stress values,strains,and displacement of the cortical and cancellous bones,as well as the degree of implant displacement.RESULTS AND CONCLUSION:(1)In the class Ⅰ bone model,when the crown-to-implant ratio reached 3 under oblique loading,the cortical bone strain exceeded the physiological limit.In the class Ⅱ bone model,under oblique loading,when the crown-to-implant ratio reached 2.5,the cortical bone strain exceeded the physiological limit.In the class Ⅲ bone model,under oblique loading,cortical bone exceeded the physiological limit when the crown-to-implant ratio reached 2.5,while cancellous bone reached the critical physiological limit at 1.In the class Ⅳ bone model,under oblique loading,when the crown-to-implant ratio reached 1.5,2,2.5,and 3,the cortical bone strain exceeded the physiological limit.In the class Ⅳ bone model,all five crown-to-implant ratios of cancellous bone exceeded physiological limits.(2)Under vertical load,the cancellous bone strain exceeded the physiological limit when the crown-root ratio reached 1,2,2.5,and 3 in the class Ⅲ bone model,and when the cancellous bone strain of the five crown-root ratios in the class Ⅳ bone model exceeded the physiological limit.(3)Under oblique or vertical load,the implant displacement of the 20 groups of models did not exceed 100 μm.(4)From the perspective of biomechanics,when patients with insufficient bone height choose implant restoration,the crown-root ratio that class Ⅰ bone can tolerate is up to 2.5 times,the crown-root ratio that class Ⅱ bone can tolerate is up to 2 times,and the crown-root ratio that class Ⅲ and class Ⅳ bones can tolerate is up to 1 times due to excessive strain of cancellous bone;but the crown-root ratio that cortical bone in class Ⅲ bone can tolerate is up to 2 times.Whether class Ⅲ bone can tolerate implant restoration with a high crown-root ratio and whether cancellous bone can tolerate higher strains needs further study.

Objective To explore the role of dapansutrile(OLT1177)in radiation-induced intestinal injury and the mechanism.Methods C57BL/6J mice were locally irradiated in the abdomen with 60Co to induce a model of radiation-induced intestinal injury.OLT1177 was intraperitoneally injected at a dose of 100 mg/kg 2 hours before irradiation and 6 hours after irradiation before the drug was administered once a day.At 12 hours after irradiation,intestinal tissues were taken for terminal deoxynucleotidyl transferase mediated nick end labeling(TUNEL)staining to detect apoptosis in intestinal tissues.At 4 days after irradiation,mouse serum was collected to detect the levels of inflammatory factors in the serum.Hematoxylin-eosin(HE)stainingwas used for the evaluation of the damage to the intestinal villus structure.Immunohistochemical staining was adopted to detect the changes in crypt proliferation in intestinal tissues.Finally,proteins were isolated from intestinal tissues,and Western blotting was employed to evaluate the activation of nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome.Results After irradiation,the intestinal villi in mice were shortened.Meanwhile,there was a notable declinein the number of cells that were proliferating in the crypts,a surge in the number of apoptotic cells,and a significant spike in the overall inflammatory level.However,administration of OLT1177 inhibited the activation of the NLRP3 inflammasome,reduced apoptosis and pyroptosis,decreased the inflammatory level,and thus improved radiation-induced intestinal injury.Conclusion Administration of OLT1177 can significantly mitigate radiation-induced intestinal injury.

Objective:To explore the value of contrast enhanced ultrasonography(CEUS) combined with shear wave elastography (SWE) in the diagnosis of urethral stricture.Methods:One hundred and twenty patients with urethral stricture were recruited, and preoperative retrograde urography, common urethral ultrasound, and CEUS were used to measure the length of the stricture site, and SWE was used to detect the elasticity value of the stricture site and its nearby spongiosum. Intraoperative urethral stricture lesion site measurements were performed to confirm the actual lesion location and length during surgery and to compare them with the lengths measured in the preoperative examination;4 months after surgery, SWE was used to detect the stiffness of the surgical site and to assess the surgical efficacy and prognosis.Results:The stenosis length measured by CEUS and intraoperative measurement had no statistical difference: (4.41 ± 1.47) cm vs. (4.37 ± 1.36) cm, t = 0.22, P>0.05. The elastic value in urethra stenosis in SWE was higher than that in normal urethra: (33.1 ± 6.7) kPa vs. (23.3 ± 4.1) kPa, there was statistical difference ( t = 13.67, P<0.05). The elastic value of unobstructed urethra and that of normal urethra after reconstruction had no statistical difference ( t = 0.95, P>0.05). Conclusions:CEUS combined with SWE is a safe, accurate and effective method to evaluate urethral stricture. SWE can be used to measure postoperative outcomes and recurrence.

Objective:To explore the value of contrast enhanced ultrasonography(CEUS) combined with shear wave elastography (SWE) in the diagnosis of urethral stricture.Methods:One hundred and twenty patients with urethral stricture were recruited, and preoperative retrograde urography, common urethral ultrasound, and CEUS were used to measure the length of the stricture site, and SWE was used to detect the elasticity value of the stricture site and its nearby spongiosum. Intraoperative urethral stricture lesion site measurements were performed to confirm the actual lesion location and length during surgery and to compare them with the lengths measured in the preoperative examination;4 months after surgery, SWE was used to detect the stiffness of the surgical site and to assess the surgical efficacy and prognosis.Results:The stenosis length measured by CEUS and intraoperative measurement had no statistical difference: (4.41 ± 1.47) cm vs. (4.37 ± 1.36) cm, t = 0.22, P>0.05. The elastic value in urethra stenosis in SWE was higher than that in normal urethra: (33.1 ± 6.7) kPa vs. (23.3 ± 4.1) kPa, there was statistical difference ( t = 13.67, P<0.05). The elastic value of unobstructed urethra and that of normal urethra after reconstruction had no statistical difference ( t = 0.95, P>0.05). Conclusions:CEUS combined with SWE is a safe, accurate and effective method to evaluate urethral stricture. SWE can be used to measure postoperative outcomes and recurrence.

Objective:To explore the effect of free transplantation of composite tissue flap from the anterior lateral aspect of the femur in repairing head skin defects with artificial dural exposure infection.Methods:A retrospective study was conducted on 13 patients admitted to the First Affiliated Hospital of Air Force Military Medical University from April 2018 to August 2020 with craniotomy complications, including craniotomy skin and soft tissue defects combined with artificial dural exposure and infection. After preoperative anti infection treatment, the neurosurgery department participated in debridement and removed the artificial dura mater as much as possible during the operation. A composite tissue flap carrying the fascia lata was designed for the anterior lateral aspect of the thigh, and the flap artery and vein were anastomosed with the superficial temporal artery and superficial temporal vein/middle temporal vein respectively. The defect of the dura mater was repaired with the fascia lata with blood supply. The flap was used to seal the wound, and the donor site was directly sutured or transplanted with autologous medium thick skin graft. The postoperative blood supply and survival of the flap, the presence of cerebrospinal fluid leakage, and the healing of the donor site were observed; The observation of dural integrity and postoperative effects of skull reconstruction using cranial magnetic resonance imaging was followed up.Results:Among the 13 patients in this group, 11 patients had their artificial dura mater completely removed, while 2 patients were not completely removed due to severe adhesion. Among them, 1 patient had a residual area of 0.8 cm×1 cm, and the other had 3 residual areas, with a maximum area of 0.5 cm×0.7 cm; All transplanted skin flaps survived, with 12 cases achieving primary healing and 1 case of partial wound rupture after suture removal, which healed after conservative dressing change; All patients had no cerebrospinal fluid leakage; There was one case of partial necrosis of the graft in the donor site, which healed after supplementing the graft; Thirteen patients underwent cranial magnetic resonance imaging at 3-6 months postoperatively, all of which showed intact dura mater; Among them, 8 patients have completed skull reconstruction surgery, and all of them have healed well after reconstruction, with a good appearance of the surgical area.Conclusions:For wounds with head skin defects and exposed artificial dura mater infection, free transplantation of the anterior lateral composite tissue flap carrying the fascia lata can effectively cover the wound and repair the dura mater defect, achieve good function and appearance, and create favorable conditions for later skull reconstruction.

Objective:To analyze the current adoption of palliative care by patients with unresectable metastatic colorectal cancer (mCRC) in China.Methods:From 1 March 2023 to 30 June 2023, a questionnaire survey was conducted by random sampling. An exclusive research platform for the Blue Book on Clinical Diagnosis and Treatment of Metastatic Colorectal Cancer. An online questionnaire was sent to medical oncologists (including chief physicians, associate chief physicians, attending physicians and residents) in general hospitals and oncology hospitals in four major regions of East, Central, South and Northeast China. The questionnaire contained 28 questions requesting basic information about doctors, the number of patients with mCRC, the status of treatment from first to fourth line and beyond, points concerning treatment of pain in patients with mCRC, and expectations for the future. A medical team was responsible for the quality control of data collected, whereas statisticians performed the data cleaning and sorting and statistical analysis.Results:A total of 300 clinical questionnaires were collected, including 217 (72%) from doctors in general hospitals and 83 (28%) from doctors in oncology hospitals. Senior physicians (including associate chief physicians and chief physicians) accounted for 65% of the respondents, attending physicians 30%, and residents 5%. Within 3 months (average for each month), 46.4±26.6% patients were diagnosed with recurrent or unresectable mCRC by each physician, 51.6±26.8% of the patients being in cancer hospitals and 44.4±26.3% in general hospitals. One hundred percent of patients receiving first-line treatment received palliative care, as did 80.3% of those receiving second-line treatment, 58.2% of those receiving third-line treatment, and 35.1% of those receiving ≥fourth-line treatment. The primary factor governing selection of first-line treatment was guideline recommendations, whereas comorbidities and the patients' physical status dictated second line to fourth line treatment. Standard first-line treatment was administered to 93.8% of eligible patients, standard second-line treatment to 94.3%; and standard third-line treatment to 73.5%. First-line therapy included targeted therapy in 63.6% of patients and immunotherapy in 2.8%; second-line therapy included targeted therapy in 63.0% of patients and immunotherapy in 2.0%; third-line therapy included targeted therapy in 59.2% of patients and immunotherapy in 2.2%; and fourth-line therapy included targeted therapy in 48.7% of patients and immunotherapy in 3.1%. First-line treatment lasted an average of 9.6 months, second-line treatment 6.7 months, third-line treatment 4.9 months, and fourth-line treatment 3.7 months. More than 70% of the patients maintained a good quality of life after receiving first and second-line treatment and more than 60% of them had ECOG performance scores of 0–1. After receiving third- and fourth-line treatment, 50%–60% of patients maintained a good quality of life and 40%–50% of them maintained ECOG performance scores of 0–1. The survey also revealed that the main deficiencies in treatment were limited effectiveness of third-line treatment, insufficient availability and opportunity for clinical research, popularity of new drugs or new drug combination strategies, and limited channels for participation in multidisciplinary diagnosis and treatment. Clinicians reported looking forward to participating in more clinical research on new drugs, hearing about the experience of experts in the field, and discovery of new targets and new drugs that increased the options for posterior line treatment of colorectal cancer.Conclusions:This report objectively summarizes the current situation, treatment difficulties, and expectations of frontline physicians concerning management of mCRC, thus providing a basis for decision-making and future direction for the diagnosis and research on treatment of mCRC.

Objective:To analyze the current adoption of palliative care by patients with unresectable metastatic colorectal cancer (mCRC) in China.Methods:From 1 March 2023 to 30 June 2023, a questionnaire survey was conducted by random sampling. An exclusive research platform for the Blue Book on Clinical Diagnosis and Treatment of Metastatic Colorectal Cancer. An online questionnaire was sent to medical oncologists (including chief physicians, associate chief physicians, attending physicians and residents) in general hospitals and oncology hospitals in four major regions of East, Central, South and Northeast China. The questionnaire contained 28 questions requesting basic information about doctors, the number of patients with mCRC, the status of treatment from first to fourth line and beyond, points concerning treatment of pain in patients with mCRC, and expectations for the future. A medical team was responsible for the quality control of data collected, whereas statisticians performed the data cleaning and sorting and statistical analysis.Results:A total of 300 clinical questionnaires were collected, including 217 (72%) from doctors in general hospitals and 83 (28%) from doctors in oncology hospitals. Senior physicians (including associate chief physicians and chief physicians) accounted for 65% of the respondents, attending physicians 30%, and residents 5%. Within 3 months (average for each month), 46.4±26.6% patients were diagnosed with recurrent or unresectable mCRC by each physician, 51.6±26.8% of the patients being in cancer hospitals and 44.4±26.3% in general hospitals. One hundred percent of patients receiving first-line treatment received palliative care, as did 80.3% of those receiving second-line treatment, 58.2% of those receiving third-line treatment, and 35.1% of those receiving ≥fourth-line treatment. The primary factor governing selection of first-line treatment was guideline recommendations, whereas comorbidities and the patients' physical status dictated second line to fourth line treatment. Standard first-line treatment was administered to 93.8% of eligible patients, standard second-line treatment to 94.3%; and standard third-line treatment to 73.5%. First-line therapy included targeted therapy in 63.6% of patients and immunotherapy in 2.8%; second-line therapy included targeted therapy in 63.0% of patients and immunotherapy in 2.0%; third-line therapy included targeted therapy in 59.2% of patients and immunotherapy in 2.2%; and fourth-line therapy included targeted therapy in 48.7% of patients and immunotherapy in 3.1%. First-line treatment lasted an average of 9.6 months, second-line treatment 6.7 months, third-line treatment 4.9 months, and fourth-line treatment 3.7 months. More than 70% of the patients maintained a good quality of life after receiving first and second-line treatment and more than 60% of them had ECOG performance scores of 0–1. After receiving third- and fourth-line treatment, 50%–60% of patients maintained a good quality of life and 40%–50% of them maintained ECOG performance scores of 0–1. The survey also revealed that the main deficiencies in treatment were limited effectiveness of third-line treatment, insufficient availability and opportunity for clinical research, popularity of new drugs or new drug combination strategies, and limited channels for participation in multidisciplinary diagnosis and treatment. Clinicians reported looking forward to participating in more clinical research on new drugs, hearing about the experience of experts in the field, and discovery of new targets and new drugs that increased the options for posterior line treatment of colorectal cancer.Conclusions:This report objectively summarizes the current situation, treatment difficulties, and expectations of frontline physicians concerning management of mCRC, thus providing a basis for decision-making and future direction for the diagnosis and research on treatment of mCRC.

Objective:To explore the factors affecting the prognosis of severe pediatric acute respiratory distress syndrome (ARDS) after receiving extracorporeal membrane oxygenation (ECMO) support.Methods:It was a multicenter prospective observational study. A total of 95 children with severe ARDS who were treated with ECMO salvage therapy from January 2018 to December 2022 in 9 pediatric ECMO centers in China were enrolled in the study. The general data, disease severity, organ function, comprehensive treatment and prognosis were recorded, and they were divided into survival group and death group according to the outcome at discharge. T test, chi-square test, multivariate Logistic regression and mixed linear model were used to analyze the relationship among baseline before ECMO treatment, some important indicators (pediatric critical scores, platelet count, albumin, fibrinogen, etc) during ECMO treatment and prognosis. Results:Among the 95 children with severe ARDS who received ECMO, 55 (58%) were males and 40 (42%) were females, aged 36.9 (0.5, 72.0) months. Twelve children (13%) were immunodeficient. Sixty-eight (72%) children were treated with venous artery (VA) mode and 27 (28%) with venous vein (VV) mode. The discharge survival rates of overall, VA, and VV mode children were 51% (48/95), 47% (32/68), and 59% (16/27), respectively. The number of immunodeficient children in the death group was higher, and there were lower pediatric critical scores, platelet count, albumin, fibrinogen and arterial oxygen partial pressure/fraction of inspired oxygen (PaO 2/FiO 2), higher ventilator driving pressure (ΔP), oxygenaion index (OI), and longer ARDS duration before ECMO (all P<0.05). There were no statistically significant differences in other indicators, including age, gender, weight, and ECMO mode among different prognostic groups (all P>0.05). High ΔP, high OI, low P/F, and low albumin were high-risk factors affecting prognosis(all P<0.05). After further grouping, it was found that ΔP≥25 cmH 2O (1 cmH 2O=0.098 kPa), P/F≤67 mmHg (1 mmHg=0.133 kPa) and OI≥35 were the thresholds for predicting poor prognosis ( P<0.05). From 24 h after ECMO, there were significant differences in ΔP, P/F and OI between the dead group and the survival group (all P<0.05), and the differences gradually increased with the ECMO process. The platelet level was significant from 7 days after ECMO ( P<0.05) and gradually expanded. Blood lactate levels showed a significant difference between the 2 groups on before and after ECMO ( P<0.05) and gradually increased from 24 h after ECMO. Conclusions:The risk factors affecting the prognosis of severe ARDS in ECMO include high ΔP, high OI, low P/F and low albumin purification therapy before ECMO. The gradual decrease of ΔP, OI and increase of P/F from 24 h of ECMO predicted a good prognosis, while the gradual increase of lactate after ECMO application showed a poor prognosis.

Objective To investigate the clinical application value of predicting the severity of acute pancreatitis(AP)based on MRI-T2WI radiomics nomogram.Methods A total of 375 patients with AP were analyzed retrospectively,who were divided into 281 cases in the training group and 94 cases in the validation group according to the ratio of 3∶1.Based on MRI-T2WI image,man-ual segmentation was performed for the pancreatic parenchyma.The radiomics feature were selected by feature extraction and dimen-sionality reduction,the support vector machine(SVM)classifier were used to construct the radiomics model.Logistic regression analysis was used to screen out independent risk factors,and an radiomics nomogram model was constructed in combined with the Radiomics score(Radscore),and the predictive performances of the models were evaluated.Results Receiver operating characteristic(ROC)curve analysis showed that the predictive efficacy of radiomics nomogram model[training group,area under the curve(AUC)=0.893;val-idation group,AUC=0.889]was higher than that of clinical model(training group,AUC=0.799;validation group,AUC=0.809)and radiomics model(training group,AUC=0.814;validation group,AUC=0.823).Conclusion The radiomics nomogram based on MRI-T2WI radiomics features and independent risk factors has high clinical application value for the prediction of AP severity.