Objective:To provide references for army application by exploring the effect of a new portable neck muscle trainer on neck muscle training for helicopter flying personnel.Methods:The helicopter flying personnel who stationed in Eastern Theater from January of 2021 to June of 2022, were selected as subjects, and assigned to observation group and control group according to the ratio of 1∶1 by random number table. The flying personnel in control group performed daily neck functional exercise by themselves, and the flying personnel in observation group used a new portable neck trainer for cervical flexion, extension and left and right lateral flexion exercise. The cervical lordosis angle, cross-sectional area and strength of neck muscles, and the neck and shoulder pain scores were compared between 2 groups and between the states before and after the training.Results:Sixty-eight helicopter flying personnel participated in the study, 34 in the observation group and 34 in the control group. By training the neck and shoulder pain scores of the flying personnel in the observation group were reduced by (0.8±0.2) points and (1.3±0.3) points respectively, with significant differences ( t=4.43, 18.55, both P<0.001), and the improvements were better than those of the control group ( t=15.65, 18.44, both P<0.001). The cervical spine lordosis improved by (3.2±1.3)° compared with the state before training in the observation group, and the muscle area of the cervical spine increased by (3.1±0.4) cm 2, which was better than that of the control group ( t=11.97, 23.32, both P<0.001). The muscle strength of anterior flexion, posterior extension and left and right lateral flexion of the cervical spine increased by 25.6%, 27.9%, 59.5% and 54.7%, respectively, which were better than those of the control group ( t=14.28, 12.02, 10.52, 14.44, all P<0.001). The maximum impulse of 10 s of forward flexion, posterior extension and left and right lateral flexion increased by 44.2%, 52.0%, 71.5% and 71.4%, respectively, which were better than that of the control group ( t=11.08, 12.94, 16.81, 10.42, all P<0.001). Conclusions:The portable cervical spine trainer can enhance the strength of neck muscles, improve cervical lordosis and relieve neck and shoulder pain, and is suggested to apply to the neck muscle exercises in field training or in the training during recuperation for flying personnel.

Objective:To provide references for army application by exploring the effect of a new portable neck muscle trainer on neck muscle training for helicopter flying personnel.Methods:The helicopter flying personnel who stationed in Eastern Theater from January of 2021 to June of 2022, were selected as subjects, and assigned to observation group and control group according to the ratio of 1∶1 by random number table. The flying personnel in control group performed daily neck functional exercise by themselves, and the flying personnel in observation group used a new portable neck trainer for cervical flexion, extension and left and right lateral flexion exercise. The cervical lordosis angle, cross-sectional area and strength of neck muscles, and the neck and shoulder pain scores were compared between 2 groups and between the states before and after the training.Results:Sixty-eight helicopter flying personnel participated in the study, 34 in the observation group and 34 in the control group. By training the neck and shoulder pain scores of the flying personnel in the observation group were reduced by (0.8±0.2) points and (1.3±0.3) points respectively, with significant differences ( t=4.43, 18.55, both P<0.001), and the improvements were better than those of the control group ( t=15.65, 18.44, both P<0.001). The cervical spine lordosis improved by (3.2±1.3)° compared with the state before training in the observation group, and the muscle area of the cervical spine increased by (3.1±0.4) cm 2, which was better than that of the control group ( t=11.97, 23.32, both P<0.001). The muscle strength of anterior flexion, posterior extension and left and right lateral flexion of the cervical spine increased by 25.6%, 27.9%, 59.5% and 54.7%, respectively, which were better than those of the control group ( t=14.28, 12.02, 10.52, 14.44, all P<0.001). The maximum impulse of 10 s of forward flexion, posterior extension and left and right lateral flexion increased by 44.2%, 52.0%, 71.5% and 71.4%, respectively, which were better than that of the control group ( t=11.08, 12.94, 16.81, 10.42, all P<0.001). Conclusions:The portable cervical spine trainer can enhance the strength of neck muscles, improve cervical lordosis and relieve neck and shoulder pain, and is suggested to apply to the neck muscle exercises in field training or in the training during recuperation for flying personnel.

Osteofacial compartment syndrome (OCS) is one of the serious complications in traumatic orthopedics. If not treated in time, OCS may result in irreversible damage to nerve and muscle,even amputation or death in serious condition. 5P presents to be the classic clinical diagnosis of OCS, but it is highly subjective and cannot timely and accurately judge the progression of the disease. Intracompartment pressure manometry is the main auxiliary method for the diagnosis of OCS. Although there are many manometry methods, there is still no authoritative pressure threshold as the diagnosis standard. Clinicians often aggressively perform fasciotomy to avoid serious complications, leading to unnecessary fasciotomy. The authors retrospectively reviewed the data of patients with OCS treated at Air Force Hospital of Eastern Theater of PLA from March 2010 to March 2020 and found that some patients with OCS had gradual alleviation of clinical symptoms after appropriate conservative treatments such as brace releasing, limb stabilization and swelling subsidence, with no need of fasciotomy. However, the symptoms of some patients progressively aggravated after the above-mentioned traditional treatments and timely fasciotomy was required. The authors graded the severity of OCS and proposed for the first time the OCS grading criteria according to quantitative clinical results and quantitative indicators such as ratio of mean blood flow velocity of bilateral arteries and pulse wave changes, aiming to take corresponding intervention measures for patients with different OCS classifications, carry out more precise treatment and avoid unnecessary fasciotomy.

Objective:To explore the protective effect and mechanism of improved St. Thomas solution on canine skeletal muscle ischemia-reperfusion injury (IRI).Methods:Between March 2021 and September 2021, in the experimental operating room at the Air Force Hospital of the PLA Eastern Theater Command, 16 Beagles were randomly divided into control group, IRI group, IRI+NS group, and improved St. Thomas group, 4 in each group. The canine skeletal muscle IRI model was established, and the canine vital signs were monitored by pre-perfusion with improved St. Thomas perfusate [potassium chloride (KCl), magnesium sulfate (MgSO 4), and NaHCO 3 (pH adjusted)]. The pathological damage of canine skeletal muscle was explored by hematoxylin eosin (HE) staining, electron microscope detection and tissue wet/dry weight ratio, and blood vessel density. Hypoxia performances were detected by labeling blood vessels and hypoxia-inducible factor-1α (HIF-1α). The IRI model of L6 rat myoblasts was established, and the components of St. Thomas perfusion solution were pre incubated to explore the effect on the inhibition of cell proliferation. And by detecting reduced nicotinamide adenine dinucleotide phosphate (NADPH), F2 isoprostane (F2-isoprostane), interleukin 1β(IL-1β), tumour necrosis factor alpha (TNF-α), myeloperoxide enzyme (MPO), glutathione peroxidase (GSH-Px), etc. to explore its protective mechanism. Statistical software SPSS 23.0 was used for statistical analysis, A P<0.05 was set as statistically significant. Results:In the improved St. Thomas group, the vital signs of the dogs were relatively stable, the amount of maintained dopamine was less, the histopathological structure of the gastrocnemius muscle tended to be intact, the swelling of tissue cells and mitochondria was significantly relieved, and the tissue wet/dry weight ratio was less than that in the IRI group ( P=0.046). Pre-incubated with therapeutic doses of MgSO 4 or NaHCO 3, the proliferation rate of L6 cells was higher than that of IRI group ( P<0.01, P=0.005), NADPH ( P=0.004, P=0.001), F2-isoprostane ( P<0.01, P=0.01), IL-1β ( P=0.02, P=0.015), TNF-α ( P<0.01, P<0.01), MPO ( P<0.01, P<0.01) were all lower than those in the IRI group, except GSH-Px that was higher than what in the IRI group ( P<0.01). Conclusion:Pre-perfusion of the improved St. Thomas solution can stabilise the vital signs of dogs in a short period of time. The solution can improve the state of skeletal muscle cells, improve tissue hypoxia, and reduce the damage of skeletal muscle tissue cells through anti-inflammatory and anti-oxidative stress.

Objective:To explore the efficacy of distracting external fixator for tibiofibular fractures combined with osteofascial compartment syndrome.Methods:A retrospective case-control study was conducted to analyze the clinical data of 62 patients with tibiofibular fractures combined with osteofascial compartment syndrome admitted to Air Force Hospital from Eastern Theater of PLA from March 2009 to March 2019, including 47 males and 15 females, aged 20-78 years［（47.1±13.4）years］. There were 30 patients with tibia shaft fractures, 17 with tibia plateau fractures and 15 with tibia distal fractures. The fractures were classified as type 4A in 18 patients, type 4B in 24 and type 4C in 20 according to AO/OT classification. Distracting external fixation was performed for 30 patients（Group A）and calcaneal tuberosity traction for 32 patients（Group B）. Levels of alanine aminotransferase（ALT）, urea nitrogen（BUN）, creatine kinase（CK）and lactate dehydrogenase（LDH）of the injured limb were compared between the two groups during traction. Additionally, the fasciotomy rate, time of damage control treatment（observation interval from trauma to stage II definitive surgery）, time of stage II definitive surgery, internal fixation modalities of stage II definitive surgery, rate of needle tract infection and rate of non-planned secondary surgery were compared between the two groups. The limb function was assessed using Johner-Wruhs scoring system at the last follow-up.Results:All patients were followed up for 12-22 months［（15.1±2.7）months］. Level of CK in Group A was 315.6（140.0, 531.5）U/L, significantly lower than that in Group B［465.5（277.0, 1240.5）U/L］（ P<0.05）. The two groups revealed no statistical differences in levels of BUN, CK and LDH（ P>0.05）. The fasciotomy rate in Group A［40%（12/30）］was higher than that in Group B［34%（11/32）］, but the difference was statistically insignificant（ P>0.05）. The time of stage II definitive surgery in Group A was（68.5±17.1）minutes, significantly lower than that in Group B［（89.0±15.1）minutes］（ P<0.05）. The rate of non-planned secondary surgery in Group A［3%（1/30）］was lower than that in Group B［25%（8/32）］（ P<0.05）. There were no statistically significant differences in time of damage control treatment, internal fixation modalities of stage II definitive surgery and rate of needle infection between the two groups（ P>0.05）. According to Johner-Wruhs scoring system, the function in Group A were excellent in 17 patients, good in 5, fair in 2 and poor in 6 at the last follow-up, with the excellent rate of 73%. However, the difference was not statistically significant when compared to Group B: excellent in 13 patients, good in 3, fair in 7 and poor in 9, with the excellent rate of 50%（ P>0.05）. Conclusion:Compared with calcaneal tuberosity traction, the distracting external fixation of tibiofibular fractures combined with osteofascial compartment syndrome can attenuate soft tissue damage during the traction and shorten the time of stage II definitive surgery by maintaining intraoperative fracture reduction.

Objective To quantitatively judge the degree of tibial bone healing using the finite element wall thickness analysis method, so as to provide an intuitive diagnostic basis for clinical judgment of tibial union and delayed bone healing. Methods After three-dimensional (3D) modeling for the affected and healthy limb side of 48 patients, the maximum wall thickness (MWT) was calculated, and the ratio (B value) was used as a quantitative index of bone healing. When both BMWT2 and BMWT1 were greater than 0.9, bone healing could be judged. When BMWT2 was between 0.9 and 0.7, bone union was judged to be poor, and there was no significant increase in this value after regular reexamination. When BMWT3 was above 0.9 while both BMWT1 and BMWT2 were smaller than 0.7, it could be judged as internal fixation failure, which should be replaced during the second operation. The clinical diagnosis was revised twice, and the final clinical healing results were observed. Results Clinical diagnosis analysis and finite element wall thickness analysis were carried out in 48 patients during each review period, and 21 cases of delayed bone healing and 27 cases of bone nonunion were judged clinically. Among them, 2 cases were judged to be ineffective, and bone grafting intervention was adopted to replace the internal fixation, 12 cases were judged to be still effective, and all cases were finally healed by surgical intervention of bone grafting alone. By Bowker test, P=0.094 was obtained, indicating that the wall thickness analysis method was consistent with the clinical diagnosis. Conclusions The wall thickness analysis method can be used to quantitatively analyze the degree of bone healing at fracture end and realize the rapid calculation of bone healing degree. The case results in this study show that the finite element wall thickness analysis method is superior to the simple clinical diagnosis method, and has better differential diagnostic significance for early diagnosis of poor bone healing.

Objective:To examine the effects of bilobalide on ischemia reperfusion injury (IRI) of skeletal muscle cells in rats.Methods:IRI of skeletal muscle cells in L6 rats was stimulated by culturing skeletal muscle cells in a hypoxia incubator for 4 hours, which were further cultured in a conventional incubator for 4 hours. The induced rat myoblasts were randomly divided into control group, ischemia reperfusion group and bilobalide group. Rat myoblasts in control group were cultured in the conventional incubator, and cells in ischemia reperfusion group were cultured in hypoxia incubator and conventional incubator alternatively to simulate IRI of skeletal muscle cells. After 4 hours of incubation in hypoxic incubator, L6 rat myoblasts in bilobalide group were replaced with medium containing 20 μmol/L bilobalide, and then put into conventional incubator for further culture. CCK-8 assay was used to test cell viability 48 hours later. Related test kits were used to examine the levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD), xanthine oxidase (XOD), malondialdehyde (MDA) and intracellular calcium.Results:Compared with ischemia reperfusion group [(62.2±6.8)%], the viability of myoblasts was increased in bilobalide group [(86.5±5.6)%] ( P<0.05). Compared with ischemia reperfusion group [(265.3±35.2)U/mg], the level of LDH in myoblasts was decreased in bilobalide group [(125.4±16.9)U/mg] ( P<0.05). Compared with ischemia reperfusion group [(68.6±10.7)U/mg], the level of SOD in myoblasts was increased in bilobalide group [(98.5±8.4)U/mg] ( P<0.05). Compared with ischemia reperfusion group [(224.7±65.8)U/mg], the level of XOD in myoblasts was decreased in bilobalide group [(105.9±58.9)U/mg] ( P<0.05). Compared with ischemia reperfusion group [(198.2±35.7)U/mg], the level of MDA in myoblasts was decreased in bilobalide group [(100.4±25.3)U/mg] ( P<0.05). Compared with ischemia reperfusion group (2.5±0.3), the intracellular Ca 2+ concentration in cell supernatant was decreased in bilobalide group (1.6±0.3) ( P<0.05). But all the indexes tested above did not return to the level in control group ( P<0.05). Conclusion:Bilobalide can protect skeletal muscle cells from IRI by inhibiting oxidative stress reaction and calcium overload.

Objective:To explore the feasibility and effectiveness of four-dimensional analysis of wall thickness for judgment of femoral bone healing.Methods:The clinical data were retrospectively analyzed of the 29 patients who had been diagnosed with femoral bone malunion or bone nonunion at Department of Orthopaedics, Air Force Hospital of Eastern Military Theater of PLA from June 2014 to June 2019. They were 24 males and 5 females with an average age of 41.8 years (from 5 to 54 years). There were 25 cases of delayed union and 4 cases of nonunion (including 2 ones of hypertrophic nonunion and 2 ones of at-rophic nonunion). Mimics software 2.0 and the four-dimensional analysis of wall thickness were used to simulate and analyze the fracture bone healing of the patients at different time points. In comparison with the CT data of the contralateral healthy limb, the fracture bone healing was judged to assist the diagnosis of femoral union, delayed union and nonunion on the basis of the changing trends with time. The original clinical diagnoses were thus revised and the eventual clinical healing outcomes were observed.Results:All the patients were followed up for 1 to 4 years (mean, 14.9 months). Of them, bone union was clinically diagnosed in 13 (44.8%), delayed bone union in 12 (41.4%) and bone nonunion in 4 (13.8%). According to the judgment by four-dimensional analysis of wall thickness, the clinical diagnoses were modified as follows: 9 cases (31.0%) had bone union, 18 cases (62.1%) delayed bone union, and 2 cases (6.9%) bone nonunion. There were statistically significant differences between the 2 methods ( χ2=15.399, P=0.031). Conclusions:The four-dimensional analysis of wall thickness can be used to analyze quantitatively the femoral bone healing, providing a relatively objective basis for clinical diagnosis of bone nonunion and delayed bone union.

Objective To review the research progress of epidemiology , risk factors and prevention of low back pain in military pilots at home and abroad. Literature resource and selection The articles ,monographs and case reports related to low back pain (LBP) of military pilots published at home and abroad were searched and analyzed. Literature quotation Fifty-six references were cited. Literature synthesis LBP was one of the most prevalent symptoms in military pilots.By reviewing the domestic and foreign published literatures ,we founded that fighter ,helicopter and transporter pilots experienced LBP with different occurrence rates.Pilot′s LBP would affect the manipulation ,decrease mission completion quality and combat capability ,and influence flight safety. The imagining analysis showed that pilot′s LBP had varying degree of correlation with lumber disc herniation (LDH ) ,mainly at L4-5and L5-S1.LDH was a main reason of pilots′ medical grounding. Literature review revealed that age ,obesity ,positive acceleration exposure (+ Gz) ,vibration and flying hours were the main risk factors of LBP.The restrain of the influences of risk factors and active protection were the effective methods to reduce the occurrence of LBP.Such measures as applying stricter selection criteria and lumber support device ,and strengthening the lumber muscle exercise could prevent and relief LBP effectively. Conclusions LBP is the disease that caused by the combination of pilot′s own and external factors.It is helpful to enhance pilot′s performance ,reduce flight accident and improve combat capacity by correctly understanding the occurrence mechanism and risk factors of LBP and taking active protections.

Objective To review the research progress of epidemiology , risk factors and prevention of low back pain in military pilots at home and abroad. Literature resource and selection The articles ,monographs and case reports related to low back pain (LBP) of military pilots published at home and abroad were searched and analyzed. Literature quotation Fifty-six references were cited. Literature synthesis LBP was one of the most prevalent symptoms in military pilots.By reviewing the domestic and foreign published literatures ,we founded that fighter ,helicopter and transporter pilots experienced LBP with different occurrence rates.Pilot′s LBP would affect the manipulation ,decrease mission completion quality and combat capability ,and influence flight safety. The imagining analysis showed that pilot′s LBP had varying degree of correlation with lumber disc herniation (LDH ) ,mainly at L4-5and L5-S1.LDH was a main reason of pilots′ medical grounding. Literature review revealed that age ,obesity ,positive acceleration exposure (+ Gz) ,vibration and flying hours were the main risk factors of LBP.The restrain of the influences of risk factors and active protection were the effective methods to reduce the occurrence of LBP.Such measures as applying stricter selection criteria and lumber support device ,and strengthening the lumber muscle exercise could prevent and relief LBP effectively. Conclusions LBP is the disease that caused by the combination of pilot′s own and external factors.It is helpful to enhance pilot′s performance ,reduce flight accident and improve combat capacity by correctly understanding the occurrence mechanism and risk factors of LBP and taking active protections.