Objective:To establish and assess the precision of pre-surgical condyle position planning using mandibular movement trajectory data for orthognathic surgery.Methods:Skull data from large-field cone beam computed tomography(CBCT)and dental oral scan data were imported into IVSPlan 1.0.25 software for 3D reconstruction and fusion,creating 3D models of the maxilla and mandible.Trajectory da-ta of mandibular movement were collected using a mandibular motion recorder,and the data were inte-grated with the jaw models within the software.Subsequently,three-dimensional trajectories of the con-dyle were obtained through matrix transformations,rendering them visually accessible.A senior oral and maxillofacial surgeon with experience in both diagnosis and treatment of temporomandibular joint disease and orthognathic surgery selected the appropriate condyle position using the condyle movement trajectory interface.During surgical design,the mobile mandibular proximal segment was positioned accordingly.Routine orthognathic surgical planning was completed by determining the location of the mandibular distal segment,which was based on occlusal relationships with maxilla and facial aesthetics.A virtual mandible model was created by integrating data from the proximal and distal segment bone.Subsequently,a solid model was generated through rapid prototyping.The titanium plate was pre-shaped on the mandibular model,and the screw hole positions were determined to design a condylar positioning guide device.In accordance with the surgical plan,orthognathic surgery was performed,involving mandibular bilateral sagittal split ramus osteotomy(SSRO).The distal segment of the mandible was correctly aligned inter-maxillary,while the proximal bone segment was positioned using the condylar positioning guide device and the pre-shaped titanium plate.The accuracy of this procedure was assessed in a study involving 10 patients with skeletal class Ⅱ malocclusion.Preoperative condyle location planning and intraoperative po-sitioning were executed using the aforementioned techniques.CBCT data were collected both before the surgery and 2 weeks after the procedure,and the root mean square(RMS)distance between the preope-rative design position and the actual postoperative condyle position was analyzed.Results:The RMS of the condyle surface distance measured was(1.59±0.36)mm(95％CI:1.35-1.70 mm).This value was found to be significantly less than 2 mm threshold recommended by the expert consensus(P＜0.05).Conclusion:The mandibular trajectory may play a guiding role in determining the position of the mandibular proximal segment including the condyle in the orthognathic surgery.Through the use of a con-dylar positioning guide device and pre-shaped titanium plates,the condyle positioning can be personalized and customized with clinically acceptable accuracy.

Brain aging is closely related to cognitive decline,neurodegenerative diseases,and vascular dementia.Hydrogen sulfide(H2S)can delay brain aging by regulating protein homeostasis,anti-oxidative stress,inhibiting inflammation,reducing brain cell apoptosis and improving microcirculation.

Objective:To compare the effect of F7.5 ureteroscope and other types of ureteroscope (F8.5, F9.0, F9.2, F9.6) in the control of intrapelvic pressure during operation.Methods:F7.5 super thin flexible ureteroscope and other 4 kinds of disposable flexible ureteroscopes (F8.5, F9.0, F9.2, F9.6) were combined with 3 kinds of ureteral guidance sheaths to form 15 endoscope-sheath combinations. The real outer diameter of each flexible ureteroscope was measured and the effective ratio of endoscope-sheath diameter was calculated. The real outer diameter of each soft mirror was measured and the effective sheath ratio was calculated. The irrigation during lithotripsy was simulated in a 3D printed kidney model, the irrigation pressure of 50-500 cmH 2O was set, and the stable intrapelvic pressure and flow rate were measured. The line chart was drawn and the relationship between intrapelvic pressure and irrigation pressure was analyzed by linear regression. The intrapelvic pressure between different endoscope-sheath combinations and different endoscope groups were compared respectively. Results:The ratio of endoscope-sheath diameter for all combinations ranges from 0.62 to 0.92, with 0.75, 0.68 and 0.62 for the F7.5 flexible ureteroscopes and F10/12, F11/13 and F12/14 sheath combinations respectively. Intrapelvic pressure and flow rate showed an approximately linear relationship with irrigation pressure in all groups. The F7.5 flexible scope with the F10/12, F11/13 and F12/14 sheaths all provided intrapelvic pressures below 40 cmH 2O. The F12/14 sheath-F7.5 scope combination produced the lowest intrapelvic pressure of 1.47 cmH 2O at 50 cmH 2O irrigation pressure and the highest flow rate of 74.24 ml/min at 500 cmH 2O irrigation pressure. When combined with the F10/12 sheath, only the F7.5 flexible scope was able to maintain a safe intrapelvic pressure of only 25.90 cmH 2O throughout. Analysis of the variability of intrapelvic pressure using the combination of instruments as the grouping variable suggested a significant overall difference( P<0.05). Analysis of the variability between groups using the different flexible scope as the grouping variable showed that the F7.5 scope group had significantly lower intrapelvic pressure compared to the other four groups( P<0.05). Conclusions:The F7.5 super thin flexible scope has the best intrapelvic pressure control of the five flexible scopes due to the significantly reduced ratio of endoscope-sheath diameter for the instrument combination and the ability to fit a thinner guide sheath while maintaining safe pelvic pressure.

Objective:To summarize the clinical characteristics of children with rheumatic disease combined with endocrine disorder.Methods:A retrospective analysis was performed on the clinical data, including sex, age, clinical presentation, laboratory tests, treatment and outcome, of 13 patients with rheumatic diseases combined with endocrine disorder, who were admitted to our department in Children′s Hospital, Capital Institute of Pediatrics from January 2014 to December 2020.Results:Among the 13 cases, 3 were males and 10 were females, without family history. Their age was (10±4) years. And the average course of disease was 4.1 months. Eight of them were diagnosed with systemic lupus erythematosus (JSLE), 2 with juvenile idiopathic arthritis (JIA), 1 with childhood vasculitis, 1 with juvenile-onset systemic sclerosis (JSSc) and 1 had juvenile dermatomyositis (JDM). Regarding the initial presentation, 10 cases had symptoms of rheumatic disease, 2 had polydipsia and polyuria, and 1 had goiter. All the 13 patients had multiple system involvement. Regarding endocrine disorder, 10 had thyroiditis or subclinical thyroiditis, 4 had diabetes mellitus and one had both thyroid and pancreas involvement. Thyroid stimulating hormone in 10 patient with thyroid involvment was 19.6 (5.2-34.0) mU/L, and their total thyroxine was 75.3 (45.2-105.4) nmol/L. Besides, thyroid peroxidase antibody or thyroglobulin antibody was positive in 7 cases. The blood glucose of 4 children with pancreatic injury was 25.0 (17.0-33.0) mmol/L, and C-peptide was 0.4 (0.3-0.5) mg/L. Glutamate dehydrogenase antibody, protein tyrosine phosphatase antibody and zinc transporter 8 antibody were positive in two cases. After treatement with immunosuppressant or immunoglobulin combined with glucocorticoid or nonsteroidal antiinflammatory drugs for rheumatic symptoms, and levothyroxine or insulin for endocrine diseases, they were all followed up for more than 6 months and maintained clinical stability.Conclusions:Rheumatic diseases in children can be complicated with endocrine disorders, and the involved organs are usually thyroid and pancreas. In children with rheumatic disease, thyroid injury usually has subtle onset, whereas pancreas injury develops rapidly, even life-threatening. Insulin should be used persistently under the instruction of endocrinologist.

Objective To evaluate the diagnostic role of 18 F-fluorodeoxyglucose (FDG) PET/ CT in female patients with ascites of unknown origin by analyzing the characteristics of PET/ CT images. Meth?ods From April 2011 to December 2016, 117 female (average age: 58 years) with ascites of unknown ori-gin who underwent 18 F-FDG PET/ CT or whose ascites were found by PET/ CT were retrospectively analyzed. The causes of ascites, level of ascites metabolism in PET/ CT, diagnostic efficacy of PET/ CT for localizing primary tumor and metastasis were analyzed. Two-sample t test was used to analyze the data. Results The most common cause of female ascites was ovarian cancer, accounting for 35.0％(41/ 117). The mean stand-ardized uptake value (SUVmean ) of malignant ascites was higher than that of benign ascites (1.41±0.40 vs 0. 94±0.47; t= 3.92, P<0.05). The total detection rate of 18 F-FDG PET/ CT for primary or metastatic tumor in malignant ascites was 89.4％(93/ 104), and 75.6％(31/ 41) for malignant ascites originating from ovari-an cancer. For patients with ovarian cancer, 18 F-FDG PET/ CT clearly localized the primary tumors in 24. 4％(10/ 41) patients and metastasis in 51.2％(21/ 41) patients. Conclusions Ovarian cancer is the most common cause of female ascites. 18 F-FDG PET/ CT has a high diagnostic value for qualitative and etio-logical diagnosis for ascites of unknown origin in females.

Objective To analyze the imaging characteristics of 18 F-fluorodeoxyglucose ( FDG) PET/ CT in patients with multiple myeloma (MM). Methods Sixty-eight patients (41 males, 27 females, age (61.5±17.2) years) with pathologically proven MM were retrospectively reviewed between January 2011 and August 2016. Imaging characteristics of 18 F-FDG PET/ CT in patients were analyzed. Maximum stand-ardized uptake value (SUVmax ), score of the bone involvement (bones of whole body were classified into 10 groups, and when 1 group was involved, the score was 1), the number of bone lesions and soft tissue swell-ing around bone lesions were investigated. Results A total of 1310 lesions were detected in 68 MM pa-tients. The SUVmax varied widely and mild metabolic activity (2.5≤SUVmax<5.0) was observed in the high-est proportion of MM patients (49.8％, 652/ 1310). The SUVmax of MM patients was 6.63±3.02. The score of bone involvement was 4.49±3.01. The number of bone lesions was 10.50(3.00, 33.00), and soft tissue swelling around bone lesions was observed in 22 patients. Conclusions There are special imaging charac-teristics of 18 F-FDG PET/ CT in MM patients, such as multiple osteolytic lesions with mild to moderate met-abolic activity, clear boundary and extensive bone involvement, and lesions usually limit to the skeletal sys-tem. The characteristics are of certain value in the diagnosis and differential diagnosis of MM.

Objective To explore the value of SUV in patients with ascites of unknown cause.Methods A total of 55 patients (24 males,31 females,average age 54.8 years,age range:23-82 years) with ascites of unknown cause who underwent 18F-FDG PET/CT scan were retrospectively enrolled in this study.SUVmax and SUVmean of ascites and liver were measured and their ratios (T/NT) were calculated and compared by two-sample t test.All patients were followed up and had final diagnoses.Sensitivity,specifici ty,accuracy,positive predictive value and negative predictive value were calculated respectively.The diagnostic efficiency was compared among 18F-FDG PET/CT tumor localization alone,ascites radioactivity and ascites cytology examination by x2 test or Fisher exact test.Results Besides the high metabolized primary lesions and/or metastasis,the liver and spleen swamped by ascites with high radioactivity were visualized on MIP images.The SUVmax and SUVmean of malignant ascites were 1.78±0.65 and 1.37±0.38 respectively,which were higher than those of benign ascites (1.11±0.36 and 0.72±0.22; t=4.13,6.82,both P＜0.05).T/NT of malignant ascites was higher than that of benign ascites (SUVmax:0.64±0.20 vs 0.48±0.12,t =3.27,SUVmeax:0.68±0.17 vs 0.38±0.10,t =7.21 ; both P＜0.05).The diagnostic sensitivity,specificity and accuracy of SUV in ascites were 75.0％ (27/36),94.7％ (18/19) and 81.8％ (45/55),respectively.The sensitivity and accuracy of SUV were higher than those of cytological examination (44.4％ (16/36) and 63.6％ (35/55) ; x2 =6.98,4.58,both P＜0.05).The specificity of SUV was higher than that of tumor localization by 18F-FDG PET/CT (63.2％,12/19; x2 =5.70,P＜0.05).Conclusion Significantly higher SUVmax and SUV in malignant ascites than benign ascites were noted,which might play an adjuvant role in patients with ascites of unknown cause.