Objective The finite element method was used to analyze the effect of height of bone graft on adjacent segment stress after anterior cervical decompression and fusion.Methods One healthy adult male was included in this study.A detailed,geometrically accurate three-dimensional cervical spine model had been successfully developed from computed tomography (CT) scanning of a healthy adult male.A pure moment of 1.0 N· m was applied in different directions on the upper endplate of C3 to simulate flexion,extension,left-right lateral bending,and left-right axial rotation.We did biomechanical experiment with goat cervical specimens in terms of the moment-rotation responses.The finite element (FE) model was compared and validated with the experimental data.The relevant data in the literature was also applied for comparison and validation.To construct the post-surgery model,we turned the property of disk annulus and disk nucleus into that of the cancellous bone at C4-5.The internal fixation systems were also implanted.We changed the height of bone graft in C4-5 to be 90％,150％,175％ and 200％ of the height between C4-5 pre-surgery.The finite element models were built to simulate the post-surgery scenarios with different bone graft height,respectively.A stress analysis was conducted on the bone graft and adjacent disks.Results Under different height of bone graft,the maximum yon Mises stress on C3-4 showed when the height of bone graft was 200％.The values were 0.99 MPa,0.85 MPa,0.91 MPa and 0.89 MPa in different loading condition.The values at 150％ of the height between C4-5 pre-surgery were only 81％,73％,80％ and 87％ of the values at 200％.For C5-6,the maximum yon Mises stress were 0.77 MPa,0.83 MPa,0.91 MPa and 0.81 MPa,observed at the height of bone graft was 175％ except extension.The values at 150％ of the height between C4-5 pre-surgery were only 76％,93％,86％ and 78％ of the biggest values.With regard to C4-5,the biggest yon Mises stress was 1.25 MPa,1.77 MPa,1.75 MPa and 1.81 MPa.It was observed when the height of bone graft was 200％ of the height between C4-5 pre-surgery.The values were smallest under height of 150％ of the height between C4-5 pre-surgery.The smallest values were 63％,63％,75％ and 52％ of the biggest values.The higher the bone graft was,the bigger the maximum von Mises stress on bone graft.In a word,it seems that the smallest stress was observed when the bone graft height was 150％.Concltusion The height of bone graft makes an important difference on the stress of adjacent segment after anterior cervical decompression and fusion.150％ of the height between C4-5 presurgery was proper bone graft height.In this case,the stress on the adjacent segments intervertebral disc is smaller.The probability of adjacent segments degeneration is smaller.

Objective:To evaluate the efficacy and safety of traditional Chinese medicine (TCM) in the treatment of post stroke cognitive impairment (PSCI). Method:Seven databases, including CNKI, WanFang, VIP, CBM, PubMed, The Cochrane library and ClinicalTrials.gov, were electronically searched for relevant randomized controlled trials (RCTs) of TCM in the treatment of PSCI. The Cochrane risk of bias assessment tool was used to evaluate the methodological quality of the included studies, descriptive analysis was carried out on the included studies, and the Meta quantitative analysis was carried out with RevMan 5.3 software. Result:A total of 16 RCTs were included with 1 296 participants, and they were assigned to the intervention group (n=649) and the control group (n=647). The results showed that TCM combined with western medicine group and TCM group were better than western medicine group in improving the scores of Montreal Cognitive Assessment (MoCA), Mini-mental State Examination (MMSE), Barthel Index (BI), Activity of Daily Living (ADL), Chinese stroke scale (CSS) and National Institutes of Health stroke scale (NIHSS) of PSCI patients, and no serious adverse events were observed. Conclusion:TCM has potential advantages in improving the cognitive function of patients with PSCI, and it also has certain efficacy in improving the daily living ability and neurological impairment symptoms, and no serious adverse events have been observed. Due to the low quality of methodology included in the studies, in order to provide reliable basis for clinical decision-making, high-quality of RCTs are still needed to study the efficacy and safety of TCM for PSCI.