BACKGROUND:Medial tibial stress syndrome is a common chronic lower limb injury among runners,potentially linked to the"muscle traction theory."However,this hypothesis has not been fully confirmed.OBJECTIVE:To investigate whether the contraction characteristics of the soleus,posterior tibialis,and flexor digitorum longus muscles during running are correlated with stress levels at the medial tibial border and influence the occurrence and development of medial tibial stress syndrome using musculoskeletal simulation systems and finite element analysis.METHODS:Motion capture data of six subjects running at different speeds were input into the Anybody Modeling System for inverse dynamic simulations during the stance phase at running speeds of 2.5,3.5,and 4.5 m/s.The calculated boundary conditions were combined with finite element models to examine the stress distribution on the medial tibia.Partial least squares regression was used to analyze the correlation between independent variables(muscle force and elastic potential energy)and the dependent variable(tibial stress).RESULTS AND CONCLUSION:(1)There were statistically significant differences in tibial stress levels across different speeds during the stance phase(1％-50％)(P=0.044,F=3.834,ηp2=0.040).(2)Among the three speeds,the average correlation between soleus muscle force and tibial stress was the highest(r=12.999),followed by the correlation between posterior tibialis muscle force and tibial stress(r=-10.735),flexor digitorum longus muscle force(r=-9.751),posterior tibialis elastic potential energy(r=8.012),soleus elastic potential energy(r=9.076),and flexor digitorum longus elastic potential energy(r=-4.782).(3)The results indicate that with increasing running speed,tibial stress levels rise.The contraction of the soleus muscle and the release of absorbed elastic potential energy during running have a significant impact on the development of medial tibial stress syndrome,whereas the roles of the posterior tibialis and flexor digitorum longus muscles have been overestimated.Overall,the study supports the hypothesis that the contraction of the soleus muscle plays a crucial role in the development of medial tibial stress syndrome,consistent with the"muscle traction"hypothesis.

BACKGROUND:Medial tibial stress syndrome is a common chronic lower limb injury among runners,potentially linked to the"muscle traction theory."However,this hypothesis has not been fully confirmed.OBJECTIVE:To investigate whether the contraction characteristics of the soleus,posterior tibialis,and flexor digitorum longus muscles during running are correlated with stress levels at the medial tibial border and influence the occurrence and development of medial tibial stress syndrome using musculoskeletal simulation systems and finite element analysis.METHODS:Motion capture data of six subjects running at different speeds were input into the Anybody Modeling System for inverse dynamic simulations during the stance phase at running speeds of 2.5,3.5,and 4.5 m/s.The calculated boundary conditions were combined with finite element models to examine the stress distribution on the medial tibia.Partial least squares regression was used to analyze the correlation between independent variables(muscle force and elastic potential energy)and the dependent variable(tibial stress).RESULTS AND CONCLUSION:(1)There were statistically significant differences in tibial stress levels across different speeds during the stance phase(1％-50％)(P=0.044,F=3.834,ηp2=0.040).(2)Among the three speeds,the average correlation between soleus muscle force and tibial stress was the highest(r=12.999),followed by the correlation between posterior tibialis muscle force and tibial stress(r=-10.735),flexor digitorum longus muscle force(r=-9.751),posterior tibialis elastic potential energy(r=8.012),soleus elastic potential energy(r=9.076),and flexor digitorum longus elastic potential energy(r=-4.782).(3)The results indicate that with increasing running speed,tibial stress levels rise.The contraction of the soleus muscle and the release of absorbed elastic potential energy during running have a significant impact on the development of medial tibial stress syndrome,whereas the roles of the posterior tibialis and flexor digitorum longus muscles have been overestimated.Overall,the study supports the hypothesis that the contraction of the soleus muscle plays a crucial role in the development of medial tibial stress syndrome,consistent with the"muscle traction"hypothesis.

Objective To quantify the lower limb muscle synergy characteristics of athletes during the abdominal take-off phase before and after exercise-induced fatigue(EIF)and reveal the impact of EIF on the lower limb muscle synergy characteristics of athletes during the abdominal take-off phase.Methods The surface electromyographic data of the lower limbs during the abdominal take-off phase of 10 second-level male athletes in track and field special classes before and after EIF intervention were compared.Muscle synergy structures were analyzed before and after EIF.The paired sample t-test was used to compare the differences in synergy parameters before and after EIF.Results Two synergistic elements were extracted before and after EIF,and alternate activation of the muscle synergy structures was observed.After EIF,the degree of activation of synergy element 2 decreased significantly from 53.21±7.90 to 43.44±10.23.However,there was no significant change in synergy element 1.After EIF,the contribution of the rectus femoris muscle of synergy element 1 significantly increased from 0.37±0.04 to 0.44±0.07,and the contribution of the semitendinosus muscle decreased significantly from 0.13±0.05 to 0.08±0.05.Conclusions During abdominal take-off,as fatigue increases,the activation degree of the synergistic elements of each lower limb muscle decreases,and the contribution of the rectus femoris muscle in the synergy element to absorb the ground reaction force increases.This indicates that the rectus femoris muscle is at risk of sprain,and prevention of rectus femoris muscle injury should be strengthened.

Objective:To analyze the biomechanical characteristics of the knee joint under different lateral cut angles and ground contact modes using the validated finite element model of the knee joint,which provided a theoretical basis for preventing lateral cut sports injuries in football players and formulating rehabilitation training pro-grams after injury. Method:Fifteen male football players(all of whom are national second-level athletes and above)were recruit-ed to perform cutting movements at the angles of 45°,90° and 135° in front and rear touchdown modes at a speed of 6m/s±10％.The kinematics and dynamics data of the knee joint were calculated by Visual 3D soft-ware,and the peak moment of ground reaction force in the six touchdown actions was numerically simulated based on the verified knee joint model. Result:①The cutting angle is positively correlated with the peak knee flexion angle(P＜0.05),indicating that as the cutting angle increases,while vertical ground reaction force decreases significantly with increase cutting angle(P＜0.05).②Significant differences in kinematics and dynamics exist between forefoot and rearfoot strik-ing(P＜0.05).In the forefoot striking mode,there are larger knee flexion angles,external rotation,and inter-nal rotation peak angles,along with higher upward ground reaction force.③At the moment of side cutting contact,the distribution of Von Mises stress in the meniscus and the contact stress in the femoral cartilage show characteristics related to the cutting angle and the mode of foot contact.In the 90° rearfoot striking mode,there is a noticeable concentration of stress on the external edge of the medial meniscus and the medi-al femoral cartilage,which may indicate an increased risk of knee joint injury under these conditions. Conclusion:Performing a 90° cut with a rearfoot striking pattern may lead to an imbalance in internal knee joint stress,particularly causing significant stress concentration on the external edge of the medial meniscus,indicating a higher risk of injury.

With the changes in the disease spectrum and the advancement of examination technology, the detection rate of multiple primary lung cancers (MPLC) is gradually increasing when multiple nodules and masses in the lung are examined clinically. MPLC has significant distinction with other types of lung diseases or lung cancers in the treatment and prognosis. In most cases, patients would be recommended to undergo the surgery as soon as possible which means that the accurate diagnosis should be made before surgery or during treatment. The newly developed molecular and genomic methods are more likely to better determine the relationship between multiple lesions. Artificial intelligence can be used as a related diagnostic aid to show more accurate and objective results in the diagnosis of multiple pulmonary nodules. This review summarizes the latest MPLC diagnostic research (including pathological analysis, imaging), analyzes surgical treatment methods, and looks forward to the future research direction of MPLC diagnosis and treatment, in order to provide reference for MPLC research.

Lung cancer, as one of the malignant tumors with the fastest increasing morbidity and mortality in the world, has a serious impact on people's health. With the continuous advancement of medical technology, more and more medical methods are applied to lung cancer screening, which has gradually increased the detection rate of early lung cancer. At present, the standard operation for the treatment of early non-small cell lung cancer (NSCLC) is still lobectomy and mediastinal lymph node dissection. There is a growing trend to use segmentectomy for the treatment of early stage lung cancer. Anatomical segmentectomy not only removes the lesions to the maximum extent, but also preserves the lung function to the greatest extent, and its advantages are also obvious. This article reviews the progress of anatomical segmentectomy in the treatment of early NSCLC.

Objective:To evaluate the effects of simultaneous integrated boost intensity-modulated radical radiotherapy (SIB-IMRT) on the long-term prognosis of patients with cervical and upper thoracic esophageal cancer.Methods:From January 2011 to December 2014, a retrospective analysis was performed in 172 patients with cervical and upper thoracic esophageal cancer who were eligible for IMRT. First, the prognosis of all the patients was evaluated using single factor and multivariate analyses. According to the different irradiation method of the patients, the patients were divided into two groups, one of which received conventional IMRT (C-IMRT) and the other of which received SIB-IMRT. Propensity score matching (PSM) analysis was applied to match the two groups of patients and to determine the treatment efficacy of patients after PSM, prognostic factors, failure modes, and side effects. SPSS19.0 statistical software was used to conduct statistical analysis.Results:The median overall survival (OS) and progression-free survival (PFS) times of all the patients were 30 months and 20 months, respectively. The fact whether the surrounding tissues and organs of esophageal lesions were invaded, clinical node staging (cN staging), chemotherapy, and GTV-maximum transverse diameter were observed to be independent influencing factors of OS and PFS in all the patients ( P<0.001, P=0.013, 0.005, 0.002; P<0.001, P=0.017, 0.034, 0.002). In addition, the independent influencing factors of PFS showed short-term efficacy ( P=0.036). After PSM, there were 54 patients in each of the two groups. The result of multivariate analysis showed that the fact whether the surrounding tissues and organs of esophageal lesions were invaded, cN staging, cTNM staging, prescribed dose, GTV-maximum transverse diameter, and irradiation method were independent factors affecting the OS ( P<0.001, P=0.008, 0.014, 0.021, 0.010, 0.008). Similarly, the fact whether the surrounding tissues and organs of esophageal lesions were invaded, cN staging, and GTV-maximum transverse diameter were observed to be independent factors that affect the PFS of patients ( P<0.001, P=0.044, 0.013). The difference in the total failure rate (70.4% vs. 50.0%) and the local regional recurrence rate (61.1% vs. 31.5%) between the C-IMRT and SIB-IMRT groups after treatment was significant ( χ2=4.68, 9.53, P=0.031, 0.002). The incidence of radiation pneumonitis of grade ≥ 1 in the C-IMRT group was significantly higher than that of the SIB-IMRT group ( χ2=6.16, P=0.046), whereas the leukocyte suppression of grade ≥ 2 in the C-IMRT group was significantly lower than that in the SIB-IMRT group ( χ2=12.77, P=0.005). Conclusions:As shown by the result of this study, compared with C-IMRT, SIB-IMRT can improve the OS of patients with cervical and upper thoracic esophageal cancer to a certain extent. Whether SIB-IMRT can improve the PFS of patients requires further research.

Objective:To analyze the cause of varicocele (VC) recurrence and investigate the efficacy of sub-inguinal microsurgical varicocelectomy (MV) for recurrent VC.Methods:All of 16 inpatients diagnosed as recurrent VC, in the Department of Andrology of the Affiliated Hospital of Qingdao University from 2015 April to 2019 April, were performed sub-inguinal MV. The age of the inpatients was 18-36 years old, median 27 years old.5 cases were originally performed retroperitoneal high ligation of spermatic vein and other 11 cases were originally performed laparoscopic varicocelectomy. During the review one to three years after the previous operation, all of 16 patients were diagnosed as VC recurrence. The complains of these patients during the review included male subfertility (10 cases) and scrotal pain (12 cases), in which 6 cases’ complains were male subfertility with scrotal pain. After admission, 13 patients were classified as Grade Ⅲ (left in 8 cases, bilateral in 5 cases) and 3 patients as Grade Ⅱ (all left). The median of their visual analogue scale (VAS) was 2.5. Color doppler flow imaging (CDFI) grading showed: Grade Ⅲ in 12 cases (left in 7 cases, bilateral in 5 cases), Grade Ⅱ in 4 cases (all left). Particularly, 12 of them were Graded as Ⅲ simultaneously accompanying with Nut-cracker Phenomenon (NCP). Preoperative tests showed that the average serum testosterone was (16.2±4.9)nmol/ml, the average sperm concentration was (11.8±3.9)×10 6/ml and the progressive motility rate (PR) was (24.4±4.2)%. All of the patients were performed sub-inguinal MV using general anesthesia and supine position. The spermatic cords were clearly exposed and padded up by inserting gauze strips under them. During the operation, the field was magnified 4-6 times with the microscope. Then all of the dilated external and internal spermatic veins were ligated, at the same time the internal spermatic artery and lymph vessels were well preserved. During these operations, 11 patients underwent left-side MV, while other 5 did bilateral MVs. During these MVs, we found twisted and dilated external and internal spermatic veins in all cases and well preserved the internal spermatic arteries and lymph vessels. The number of ligated left and right external spermatic veins were(2.1±0.6) and (1.4±0.5)respectively and the number of ligated left and right internal spermatic veins were (10.1±1.1) and (6.6±0.5) respectively. We also found out(1.3±0.5) internal spermatic arteries and (3.0±1.0)lymph-vessels on left side. On right side, there were (1.4±0.5) internal spermatic arteries and (2.6±0.5) lymph-vessels respectively. At last, we summarily analyzed the pre-operative and post-operative VAS, serum testosterone, CDFI and semen analysis data. Results:All of the 16 sub-inguinal MVs were successfully performed. All patients were reviewed comprehensively 6 months after MV. The reviewed results showed that the post-operative VAS was significantly reduced ( Z=-2.994, P<0.05), palpable scrotal vessels disappeared and Valsalva tests were negative. No obvious reflux of internal spermatic veins were detected by CDFI. Interestingly, the sperm concentration and motility were both significantly improved 6 months after MV ( P<0.05), while there was not remarkable increase of the serum testosterone after MV ( P>0.05). During the follow up, no testicular atrophy, hydrocele and other complications were found. Up to submission, five of the ten patients who presented for male subfertility have impregnated their wives. Conclusions:The most possible cause of VC recurrence could be the omission of the external and internal spermatic veins, particularly in the grade Ⅲ VC patients or VC accompanied with NCP. The sub-inguinal MV, which can discover more twisted spermatic veins and at the same time preserve the spermatic artery and lymph-vessels, shows better clinical efficacy than other procedures.

Surgery is currently the most appropriate treatment for early-stage non-small cell lung cancer (NSCLC). Increasing unilateral or bilateral multiple primary lung cancer being found, segmentectomy has attracted wide attention for its unique advantages in the treatment for such tumors. Ground glass opacity dominant early-stage NSCLC is associated with a good prognosis and can be cured by segmentectomy, however, the treatment of solid-dominant NSCLC remains controversial owing to the invasive nature. With the in-depth study on the lymph node metastasis pathway, radiological characteristics and molecular biology of NSCLC, a large part of solid nodules with certain characteristics can also be cured by segmentectomy. This paper reviews the research status and progress about the indication of segmentectomy.
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Objective: To investigate the clinical significance of plasma amino-terminal pro-brain natriuretic peptide(NT-proBNP) in children with bacterial meningitis. Methods: From April 2013 to March 2017, 32 children with bacterial meningitis in PICU of the Second People′s Hospital of Liaocheng Affiliated to Taishan Medical College were selected.The patients were evaluated the severity of the disease by Glasgow coma scale(GCS). Thirty-five cases who admitted to the hospital in the same period were selected as the control group, excluding congenital heart disease, chronic cardiac dysfunction, cardiomyopathy, myocarditis, heart failure, chronic renal insufficiency.The blood samples were collected from the hospital in 24h, and the levels of the plasma NT-proBNP, procalcitonin(PCT), C-reactive protein(CRP) and Na ions were determined. Results: Compared with the control group, the levels of the plasma NT-proBNP was significantly increased[(7 123.97±6 901.60)ng/L vs.(39.29±19.41)ng/L, t=5.839, P<0.01], the level of PCT was significantly increased[(25.14±2.35)ng/dL vs.(0.63±0.15ng/dL, t=10.820, P<0.01], the level of CRP was significantly increased[(97.89±4.63mg/dL vs.(5.23±1.22mg/dL, t=21.130, P<0.01], and the GCS was significantly decreased(t=18.132, P<0.01) in children with bacterial meningitis group.The plasma NT-proBNP level of children with GCS<8points[(13 328.08±7 938.85)ng/L]was significantly higher than that in children with GCS 8~14points[(3 401.50±1 526.75)ng/L](t=5.816, P<0.01) and GCS≥15points[(39.74±18.64)ng/L](t=5.816, P<0.01). There was a significant positive correlation between the level of plasma NT-proBNP and PCT(r=0.969, P<0.01), also a significant positive correlation between the level of plasma NT-proBNP and CRP(r=0.961, P<0.01), while a significant negative correlation between the level of plasma NT-proBNP and sodium ions(r=0.886, P<0.01) in children with bacterial meningitis by Pearson correlation test. Conclusion Detection of the plasma NT-proBNP has significant clinical significance for early diagnosis and assessment of the severity of the illness of children with bacterial meningitis.