BACKGROUND:Facet joint osteoarthritis is acknowledged as a significant contributor to lower back pain in the geriatric population.The advent of an innovative spinal facet joint fusion device presents a therapeutic option for intervening during the initial stages of facet joint osteoarthritis,and significantly reduces the incidence of a series of complications caused by poor early conservative treatment and late surgical treatment.However,its effect on the biomechanics of the lumbar spine is unknown.OBJECTIVE:To investigate the biomechanical disparities between the novel lumbar zygapophyseal joint fusion device and traditional fusion devices.METHODS:A comprehensive three-dimensional finite element model of the L3-S1 lumbar spine was established and validated.Based on this intact model,three groups of surgical models were constructed:a bilateral pedicle screw fixation model,a bilateral novel facet joint fusion fixation model,and a bilateral facet screw fixation model,with the surgical segment designated as L4-5.Under a load of 500 N,a torque of 7.5 Nm was applied to all lumbar models to calculate the range of motion,displacement values,and intervertebral disc stress values at the L4-5 segment;stress values at the L3-4 and L5-S1 segments were also measured.RESULTS AND CONCLUSION:(1)Compared with the intact model,the range of motion at the L4-5 segment was reduced in all surgical models.(2)The novel device exhibited the smallest range of motion at the L4-5 segment under left and right rotational conditions;the greatest range of motion at the L4-5 segment under extension conditions;and a greater range of motion under other conditions than the bilateral pedicle screw fixation model.(3)The novel device demonstrated the smallest displacement values at the L4-5 segment under left and right rotational conditions;under other conditions,the displacement values at the L4-5 segment were greater than those in the bilateral pedicle screw fixation model.(4)In terms of stress distribution at the L4-5 segment,the novel device consistently exhibited the smallest values across all conditions.(5)For the L3-4 segment,the novel device showed the greatest stress values under extension and left and right rotational conditions,while under other conditions,the values were lower than those in the bilateral pedicle screw fixation model.(6)Compared with pedicle screw fixation,the novel device produced smaller stress values at the L5-S1 segment.(7)This study indicates that,compared with pedicle screw fixation,the novel device impacts the biomechanics of the lumbar spine by fusing the facet joints.It provides stability while preserving the range of motion at the surgical segment and reduces stress on the intervertebral discs of the surgical and adjacent segments,thereby potentially delaying disc degeneration.This suggests that the novel device can achieve biomechanical effects similar to those of pedicle screw fixation in theory.

Contralateral radiculopathy, a postoperative complication after transforaminal lumbar interbody fusion, refers to postoperative numbness, pain and other neurological symptoms of the lower limb on the side opposite to the symptomatic or the surgical decompression side. Its main causes include excessive restoration of lordosis, intervertebral space tilt caused by improper cage position, poor screw position, new protrusion of nucleus pulposus or bone graft, and hematoma. At present, attention to this complication is gradually increasing. This review summarizes its risk factors from the recent related reports of the condition and puts forward preventive measures in order to promote the preventive awareness of this complication.

BACKGROUND:Facet joint osteoarthritis is acknowledged as a significant contributor to lower back pain in the geriatric population.The advent of an innovative spinal facet joint fusion device presents a therapeutic option for intervening during the initial stages of facet joint osteoarthritis,and significantly reduces the incidence of a series of complications caused by poor early conservative treatment and late surgical treatment.However,its effect on the biomechanics of the lumbar spine is unknown.OBJECTIVE:To investigate the biomechanical disparities between the novel lumbar zygapophyseal joint fusion device and traditional fusion devices.METHODS:A comprehensive three-dimensional finite element model of the L3-S1 lumbar spine was established and validated.Based on this intact model,three groups of surgical models were constructed:a bilateral pedicle screw fixation model,a bilateral novel facet joint fusion fixation model,and a bilateral facet screw fixation model,with the surgical segment designated as L4-5.Under a load of 500 N,a torque of 7.5 Nm was applied to all lumbar models to calculate the range of motion,displacement values,and intervertebral disc stress values at the L4-5 segment;stress values at the L3-4 and L5-S1 segments were also measured.RESULTS AND CONCLUSION:(1)Compared with the intact model,the range of motion at the L4-5 segment was reduced in all surgical models.(2)The novel device exhibited the smallest range of motion at the L4-5 segment under left and right rotational conditions;the greatest range of motion at the L4-5 segment under extension conditions;and a greater range of motion under other conditions than the bilateral pedicle screw fixation model.(3)The novel device demonstrated the smallest displacement values at the L4-5 segment under left and right rotational conditions;under other conditions,the displacement values at the L4-5 segment were greater than those in the bilateral pedicle screw fixation model.(4)In terms of stress distribution at the L4-5 segment,the novel device consistently exhibited the smallest values across all conditions.(5)For the L3-4 segment,the novel device showed the greatest stress values under extension and left and right rotational conditions,while under other conditions,the values were lower than those in the bilateral pedicle screw fixation model.(6)Compared with pedicle screw fixation,the novel device produced smaller stress values at the L5-S1 segment.(7)This study indicates that,compared with pedicle screw fixation,the novel device impacts the biomechanics of the lumbar spine by fusing the facet joints.It provides stability while preserving the range of motion at the surgical segment and reduces stress on the intervertebral discs of the surgical and adjacent segments,thereby potentially delaying disc degeneration.This suggests that the novel device can achieve biomechanical effects similar to those of pedicle screw fixation in theory.

Contralateral radiculopathy, a postoperative complication after transforaminal lumbar interbody fusion, refers to postoperative numbness, pain and other neurological symptoms of the lower limb on the side opposite to the symptomatic or the surgical decompression side. Its main causes include excessive restoration of lordosis, intervertebral space tilt caused by improper cage position, poor screw position, new protrusion of nucleus pulposus or bone graft, and hematoma. At present, attention to this complication is gradually increasing. This review summarizes its risk factors from the recent related reports of the condition and puts forward preventive measures in order to promote the preventive awareness of this complication.

Objective:To construct a prediction model for prognosis of severe pneumonia patients combined with sepsis.Methods:Clinical data of 318 severe pneumonia patients combined with sepsis admitted at Taizhou People’s Hospital affiliated to Nanjing Medical University from March 2019 to March 2022 were retrospectively analyzed. Patients were randomized into a modeling set ( n=233) and a validation set ( n=85) with a 3∶1 ratio. In the modeling set there were 180 survival cases and 53 fatal cases according to the clinical outcomes within 30 days of admission. Multivariate Cox regression analysis was used to evaluate the independent prognostic factors for patients in the modeling set. A nomogram prediction model was constructed by R based on these prognostic factors and further verified using the data of the validation set with receiver operating curve (ROC), decision curve analysis (DCA), and calibrated with calibration curve analyses. Results:Multivariate Cox regression analysis suggested that septic shock ( HR=2.32, 95% CI 1.37-3.89, P=0.013) and neutrophil/lymphocyte ratio (NLR) ( HR=2.52, 95% CI 1.23-5.61, P=0.017) were independent risk factors for mortality in severe pneumonia patients combined with sepsis within 30 days of admission, while albumin/fibrinogen ratio (AFR) ( HR=0.64, 95% CI 0.41-0.83, P=0.011) and prognostic nutritional index (PNI) ( HR=0.68, 95% CI 0.57-0.83, P=0.009) were independent protective factors. The area under ROC curve (AUC) of the nomogram model based on these four indicators in the modeling and validation sets were 0.875 and 0.880, respectively. The DCA curve analysis indicated that the clinical benefit of this model was better than "All" or "None" curves in both the modeling and verification sets.The calibrate curve analysis indicated that the actual and corrected curves fitted well and were close to the ideal curve. Conclusion:The constructed nomogram model based on septic shock, AFR, NLR and PNI has a well prognostic value in severe pneumonia patients combined with sepsis.

Objective To establish the model of goat intervertebral disc degeneration （IDD） induced by controllable axial compressive stress and evaluate its imaging and pathological characteristics. Methods Twenty goats were randomly divided into 4 groups (control group, 4-week pressure group, 8-week pressure group, 12-week pressure group, n=5, 40 N pressure). Disc height index (DHI) was used to evaluate the change of intervertebral disc height by X-ray, Pfirrmann classification method was used to observe the degree of intervertebral disc degeneration by magnetic resonance imaging (MRI), and histopathological observation and evaluation for intervertebral disc were conducted by HE staining and immunohistochemistry. Results DHI in control group showed no significant changes with the extension of pressure time, while DHI in the experimental group gradually decreased. There was no significant change in Pfirrmann classification in control group. In experimental group, with the extension of time, the higher the degeneration aggravated with the Pfirrmann classification increasing. In experimental group, HE staining showed that the disc nucleus pulposus decreased in volume and nucleus pulposus cells, which were gradually replaced by fibrous tissues. Immunohistochemical staining showed that type I collagen in the nucleus pulposus gradually increased, type Ⅱ collagen gradually decreased, and intervertebral disc degeneration occurred. Conclusions A certain axial compressive stress can lead to degeneration of goat lumbar intervertebral disc, and the degree of degeneration is gradually increased with the extension of time.

Objective:To explore the effects of laser irradiation parameters (irradiation frequency and single duration) on tear secretion, lens and retina.Methods:Thirty-six healthy guinea pigs were randomly divided into 6 groups with random number table method according to different frequency and single exposure duration of laser to the eye, namely, high frequency short time (HFST) group, high frequency long time (HFLT) group, medium frequency short time (MFST) group, medium frequency long time (MFLT) group, low frequency short time (LFST) group and low frequency long time (LFLT) group, 6 for each group.The right eyes were irradiated with 500 lx laser as experimental eyes, and the left eyes of the guinea pigs served as the control eyes.The high, medium and low irradiation frequencies were defined as 15 times, 10 times and 5 times, respectively, and the short and long period was defined as 30 seconds and 60 seconds each time, respectively.The right eyes were irradiated based on the grouping at a 10-minute interval.The tear secretion was detected by SchirmerⅠtest; lens opacity was assessed under the slit-lamp microscope; fundus photography was performed to evaluate the general morphology of retina; retinal function was evaluated by electroretinogram (ERG) record and the thickness of retinal outer nuclear layer was measured by histopathology examination.This study protocol was approved by the Medical Ethics Committee of Air Force Military Medical University (No.20181203), and the use and care of the experimental animals complied with the ARVO statement.Results:The tear secretion was 8.00(7.37, 9.00), 8.75(8.25, 9.00), 8.50(7.75, 9.50), 9.00(8.50, 9.50), 8.00(7.37, 8.75) and 8.25(7.75, 8.75) mm/5 min in the HFST group, HFLT group, MFST group, MFLT group, LFST group and LFLT group, respectively, without significant difference among the groups(χ 2=5.502, P=0.240); after laser irradiation, there were no statistically significant differences in tear secretion between the control eyes and laser-irradiated eyes in all the groups (all at P>0.05). The lenses were clear and the fundus was normal through the experimental duration in all the groups.The amplitude of ERG a-wave was significantly reduced in the HFST group in comparison with the LFST group (P<0.05), and there was no significant difference in the b-wave amplitude among the six groups (F=1.358, P=0.268). The ERG a-, b-wave amplitudes were not significantly different between the control eyes and laser-irradiated eyes in various groups (both at P>0.05). There was no significant difference in the thickness of the outer nuclear layer of retina among the HFST group, HFLT group, MFST group, MFLT group, LFST group and LFLT group (F=0.952, P=0.463). Conclusions:The 500 lx laser irradiation is safe to ocular surface and lens, but there are some injuries to retinal function, and the injury degree is related to laser irradiation frequency.

B ecause of the exist of com plex m atrix, the confirm ing indicators of qualitative results for toxic substances in biological sam ples by chrom atography-m ass spectrom etry are different from that in non-biological sam ples. E ven in biological sam ples, the confirm ing indicators are different in various ap-plication areas. T his paper review s the sim ilarities and differences of confirm ing indicators for the ana-lyte in biological sam ples by chrom atography-m ass spectrom etry in the field of forensic toxicological analysis and other application areas. T hese confirm ing indicators include retention tim e (R T ), relative re-tention tim e (R R T ), signal to noise (S/N ), characteristic ions, relative abundance of characteristic ions, parent ion-daughter ion pair and abundance ratio of ion pair, etc.

Objective To investigate the clinical effect of low-molecular-weight heparin (LMWH) in the treatment of liver cirrhosis and portal vein thrombosis and the value of early application of LMWH in the prevention of portal vein thrombosis after splenectomy.Methods The databases of PubMed,Google Scholar,CNKI,Wanfang Data,and VIP were searched,and manual searching and internet searching were used to retrieve grey literature.The articles which met the inclusion criteria were included,and a systematic review and metaanalysis was performed.Results A total of 12 randomized controlled trials were included,with 1397 patients enrolled,among whom 723 were enrolled in the LMWH group and 674 were enrolled in the control group.A meta-analysis was performed for the trials above,and the results showed that the patients with early application of LMWH had a lower rate of thrombosis compared with those in the control group (OR =0.37,95％ CI 0.28-0.48,P ＜ 0.001).The results of three randomized trials with the application of LMWH in the treatment of portal vein embolism showed that the patients treated with LMWH had a higher rate of recanalization of thrombus than those in the control group (OR =5.08,95％ CI 1.74-14.84,P＜ 0.001).Conclusion Early application of LMWH can reduce the rate of portal vein thrombosis after splenectomy,and LMWH for the treatment of portal vein embolism can increase the rate of recanalization of thrombus.

A distributed simulation method of electric field based on the atrial defibrillation of the heart modeling and finite element solution is proposed in this study. In order to solve the problem that ordinary clinical trials could not measure the actual distribution of the defibrillation electric field in the heart accurately, this method provides a research tool for electrical defibrillation. A complete atrial anatomical structure in the heart model is used in the research, the finite element method is proceeded to solve; Three parameters: defibrillation threshold voltage, the high field strength rate and the defibrillation threshold energy are set to evaluate the effect of defibrillation. The heart electric field distributions of transvenous atrial defibrillation with different electrode locations or sizes are simulated. The simulation results and the reported results match fairly well, which initially verify the feasibility of this method.
Atrial Fibrillation ; therapy ; Computer Simulation ; Electric Countershock ; instrumentation ; methods ; Electrodes