Objective To explore the effect of peripheral nerve electrical stimulation on axon regeneration after spinal cord injury (SCI) in rats. Methods Nighty-two healthy Sprague-Dawley rats were randomly divided into blank control group (n=12), control group (n=40) and experimental group (n=40). All groups were suffered NYU impaction to prepare T8 SCI models, the control group and the experimental group implanted stimulating electrode on the sciatica nerve. The experimental group received electric intervention in addition. They were evaluated with BBB score one day, one week, two weeks, four weeks and eight weeks after modeling; and with motor evoked potentials (MEP) one week, two weeks, four weeks and eight weeks after modeling. Morphological changes and the expression of neurofilament pro-tein (NF)-200 and glial fibers acid protein (GFAP) were observed by HE staining and immunohistochemistry one week, two weeks, four weeks and eight weeks after modeling. Results There was no significant difference in BBB scores among three groups (P>0.05) in all the time points except eight weeks (P<0.05). There was no significant difference in the amplitudes and latencies among three groups one week after modeling (P>0.05), however, there was significant difference two weeks, four weeks and eight weeks after modeling (P<0.05). All the groups showed syringomyelia and glial scar formation one week, two weeks, four weeks and eight weeks after modeling. There was no sig-nificant difference in NF-200 axon count among three groups one week after modeling (P>0.05), but was different two weeks, four weeks and eight weeks after modeling (P<0.05). There was no significant difference in GFAP area count among three groups in all the time points (P>0.05). Conclusion Implantable peripheral nerve electrical stimulation can improve conduction function and motor function in rats with SCI. And it may promote axonal regeneration of the injured segments.

Objective To summarize the experience of aortic root surgery in Stanford A aortic dissection operations.Methods From January 2005 to September 2010, the clinical data of 59 patients with Stanford A aortic dissection was analyzed. There were 43 men and 16 women , ranging in age from 21 to 74 years old, duration of disease varied from 16 hours to 27 days. Among the group, 31 complicated by aortic valve incompetence, 12 Marfan syndrome, 9 single lower limb blood supply dysfunction, 6 right coronary artery involvement. All cases received aortic root surgery under deep hypothermic circulatory arrest. Bentall procedure was performed in 31 patients, Wheat procedure in 15 patients and David procedure in 13 patients.Results The time of cardiopulmonary bypass in the group was 149 to 204 min with an average of ( 171 ± 19) min,and the cross clamp time was 81 to 122 min with an average of (104 ±13) min, and the arrest time was 30 to 47 min with an average of (39 ±7) min. There was 1 case of operative death, which was treated on an emergency basis. Postoperative complications occurred in 20 cases. 17 cases experienced temporary mental dysfunction, 2 cases were infected with MRS A, 1 of which died from MODS, 1 case of single lower limb blood supply dysfunction remained after the first operation and recovered by reoperation (bilateral femoral bypass operation) . All cases were reexamined before discharge, postoperative mean LVEF was (56. 3 ±3.4)% (ranged 51% -62%), aortic annular diameter varied from 22 mm to 27 mm, aortic sinus diameter range from 23 mm to 31mm. 51 patients were followed up, with a mean follow-up time of (24.9 ± 17.2) months (ranged 2-54 months). 54 patients of Stanford A aortic dissection survived well with normal lives and activities. Four non cardiac deaths, one was chronic renal failure, the others were brain hemorrhage. Conclusion Prognosis and operative security of Stanford A aortic dissection patients can be significantly improved by individualized aortic root surgery.

Objective:To investigate the influence of preoperative thyroid dysfunction on the 30-day postoperative mortality and complications in elderly patients with hip fracture.Methods:A retrospective analysis was conducted of the 349 elderly patients with hip fracture who had been admitted to Department of Orthopedic Trauma, Beijing Luhe Hospital Affiliated to Capital Medical University from January 2018 to December 2019. They were 108 males and 241 females, with an average age of 76.3 years (from 60 to 104 years). There were 190 femoral intertrochanteric fractures and 159 femoral neck fractures. By the preoperative level of thyroid function, the patients were divided into a normal function group of 290 cases and a dysfunction group of 59 cases. The 2 groups were compared in terms of hospital stay, mortality and incidence of complications within 30 days postoperation.Results:In this cohort, the rate of 30-day postoperative mortality was 3.4%(12/349) and the incidence of 30-day postoperative complications 14.6%(51/349). The 2 groups were comparable because there was no significant difference between them in the preoperative general data except for the preoperative comorbidity of coronary heart disease ( P>0.05). In the dysfunction group, the hospital stay averaged (10.2±6.9) d, the rate of 30-d postoperative mortality 1.7%(1/59) and the incidence of 30-day postoperative complications 16.9%(10/59), which were insignificantly different from those in the normal function group [(10.7±7.5) d, 3.8%(11/290) and 14.1%(41/290), respectively] ( P> 0.05). Conclusion:Since preoperative thyroid dysfunction does not affect the 30-day postoperative mortality and postoperative complications in the elderly patients with hip fracture but no definite thyroid disease, routine thyroid function screening is not recommended for them.

Objective To evaluate the relationship of diurnal variation of antidiuretic hormone (ADH) with urinary output,serum osmolality and blood pressure in spinal cord injury (SCI) patients. MethodsThe study was prospective,random and contrastive. Twenty complete SCI patients (two females and 18 males,Complete SCI group) and ten healthy controls (two females and eight males,control group) were studied. Urinary output and osmolality in the day time (8:00-20:00) and at night (20:00-8:00) were recorded. Blood samples for the measurement of serum osmolality and ADH were drawn at 14:00 and 2:00. Results There was very significant difference in regard of urinary output between day time and night time in complete SCI Group and control Group ( P 0.05). However,ADH level increased in the healthy Group at night,with a very significant difference ( P

Objective To compare the short-term effects of myocapsular flap repair through minimal posterior approach in Hip arthroplasty with traditional posterior approach in hip arthroplasty in elderly femoral neck fractures. Methods From August 2007 to may 2009, a total of 126 femoral neck fracture patients were randomly divided into two groups, with 63 patients treated with myocapsular flap repair through minimal posterior approach (the modified group), and 63 patients treated with traditional posterior approach (the traditional group). Fifty-eight patients underwent the first-ever total hip replacement and 68 patients underwent artificial double-acting femoral head replacement. Eighty-four cases were inserted with cemented implants and 42 cases with uncemented. Data of incision length, operation time, blood loss volume, drainage amount, blood transfusion volumes were recorded separately. Postoperative complications related to the surgery and hip joint function were also documented. Function of hip joint was scored with Harris scale. All data were statistically analyzed. Results Five patients died within 1 year of surgery, and 4 patients dropped out. All the remained 117 patients were followed up for 12 - 24 months. There were no significant difference in age, type of fracture and artificial the incision length in the modified group was significantly shorter than that in the traditional group([ 10. 5 ± 2. 4 ]cm vs [ 17. 2 ± 3.6 ] cm, t = 3. 012, P = 0. 004). The average operating time was significantly shorter in the modified group compared to the traditional group (t = 2. 455, P = 0. 038). Blood loss, drainage amount, blood transfusion volumes in the modified group were less than those in the traditional group( t = 3.211,2. 986 and 3. 352 ,Ps ＜ 0. 01, respectively). Conclusion Myocapsular flap repair through minimal posterior approach in Hip arthroplasty is a reasonable, mini invasive technique for hip replacement in older with a less blood loss and shorter operating time.fractures

Objective To assess the feasibility of quantitative measurement of subcutaneous and supraclavicular adipose tissue with iterative decomposition of water and fat with echo asymmetry and least square estimation-iron quantification sequence (IDEAL-IQ).Methods Totally 87 normal young female volunteers (20-35 years old) were recruited and divided into body mass index (BMI)＜24 kg/m2 group (n=72) and BMI≥24 kg/m2 group (n=15).Fat fraction (FF) and T2* relaxation rate (R2*) of supraclavicular adipose tissue,chest wall adipose tissue,abdominal wall adipose tissue and liver were measured,respectively.The differences of FF and R2* value of chest wall,subcutaneous and supraclavicular adipose tissue were compared between two groups,and the correlation between FF,R2* value of supraclavicular adipose tissue and BMI was respectively analyzed.Results FF of supraclavicular adipose tissue ([80.99 ± 7.73]％) was lower than that of chest wall subcutaneous adipose tissue ([93.04 ± 1.55] ％,P＜0.001).R2* of supraclavicular adipose tissue ([65.52±23.59]Hz) was higher than that of chest wall subcutaneous adipose tissue ([38.82±7.11]Hz,P＜0.001).The differences of FF and R2* values of supraclavicular adipose tissue,chest wall,abdominal wall subcutaneous adipose tissue and liver were significant between BMI＜24 kg/m2 group and BMI≥24 kg/m2 group (all P＜0.05).There was positive correlation (r=0.601,P＜0.001) between FF of supraclavicular adipose tissue and BMI and negative correlation (r=-0.409,P =0.001) between R2* of supraclavicular adipose tissue and BMI.Conclusion IDEAL-IQ technique can quantitatively assess the difference between subcutaneous and supraclavicular adipose tissue in healthy young women.FF and R2 * value has significant difference between the above mentioned positions.

Objective:To evaluate the metal artifacts reduction effect of multi-acquisition variable-resonance image combination (MAVRIC-SL) after total knee arthroplasty by comparing with two-dimensional fast spin-echo metal artifact reduction sequence (2D FSE MARS).Methods:A total of 78 patients (101 knees) who underwent total knee arthroplasty in Beijing Tsinghua Changgung Hospital from December 2018 to December 2020 were prospectively collected. All patients underwent 3.0 T MR examination within 2 weeks after surgery. The sequences included axial, sagittal, and coronal 2D FSE MARS and MAVRIC-SL. The ranges of prosthesis artifacts were measured, and the scores of the prosthesis clarity, anatomical structure clarity, and joint effusion diagnosis confidence were evaluated by Likert scale. Paired t test was used to compare the difference of artifact range between 2D FSE MARS and MAVRIC-SL. The Wilcoxon signed rank-sum test was used to compare image quality scores and joint effusion diagnosis confidence scores. Results:In 101 knees, the ranges of prosthesis artifacts in axial, sagittal, and coronal 2D FSE MARS were (63.3±8.5), (60.0±7.4) and (62.1±8.7) cm 2, while those of MAVRIC-SL were (49.5±5.8), (44.1±6.6) and (46.1±7.5) cm 2. The differences were statistically significant ( t=20.021, 21.834, 25.472, all P<0.001). The subjective scores of femoral prosthesis clarity, tibial prosthesis clarity, and anatomical structure clarity of MAVRIC-SL were significantly higher than those of 2D FSE MARS (all P<0.001). Confidence scores of 2D FSE MARS and MAVRIC-SL for diagnosing joint effusion were 2 (1, 3) and 3 (2, 3), respectively, and the difference was statistically significant ( Z=6.549, P<0.001). Conclusion:Compared with 2D FSE MARS, MAVRIC-SL can further reduce the metal artifacts in total knee arthroplasty and improve the diagnostic confidence of joint effusion.

Objective:To explore the feasibility of the AI intelligent reconstruction model based on knee joint magnetic resonance data developed by Nuctech Company Limited for evaluating knee cartilage injury.Methods:Thirty-three patients (a total of forty-one knees) who were hospitalized with severe knee osteoarthritis in Beijing Tsinghua Changgung Hospital from May 2021 to April 2022 were selected. All of them were planned to be performed total knee arthroplasty (TKA) for the treatment of knee osteoarthritis. Fifteen males with an average age of 71±5 years old and twenty six females with an average age of 71±9 years old were included in this study. There were 19 cases of left knee and 22 cases of right knee. Thin layer MRI examination on the patients' knee joints was performed before the surgery, and artificial intelligence model based on the thin layer MRI data of the knee joint was reconstructed. The cartilage part of the model was selected and corrected by Principal Component Analysis (PCA) in order to realize model straightening. The tibial plateau cartilage of knee joint which intercepted during operation was classified according to the International Cartilage Repair Society (ICRS). Finally the results were compared with the ICRS classification results of knee artificial intelligence reconstruction model and artificial recognition of knee joint MRI images.Results:Compared with the grade of cartilage injury intercepted during our operation which was according to the ICRS classification, the sensitivity of artificial intelligence reconstruction model for the diagnosis of cartilage injury with ICRS classification grade four was 93.1%. The specificity of artificial intelligence reconstruction model was 91.4%. The positive predictive value (PPV) of artificial intelligence reconstruction model was 92.2%. And the negative predictive value (NPV) of artificial intelligence reconstruction model was 80.3%. The area under ROC curve (AUC) was 0.92. The ICRS classification consistency between artificial intelligence model and physical inspection results was good with kappa value 0.81 ( P<0.001) . In the aspect of artificial recognition of cartilage injury grading in MRI images, the sensitivity of artificial recognition was 92.10% compared with the manual identification of cartilage injury classification in MRI images. The specificity of artificial recognition was 91.60%. The positive predictive value (PPV) of artificial recognition was 97.20% and the negative predictive value (NPV) of artificial recognition was 78.8%. The kappa value of the cartilage injury classification in MRI images consistency between artificial recognition and manual identification was 0.79 ( P<0.001). Conclusion:Based on the evaluation of cartilage injury by AI reconstruction model of knee joint, the sensitivity and specificity of the diagnosis of ICRS grade IV cartilage injury can be acceptable, but still needs to be improved.